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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="thread.synchronization"></a><a class="link" href="synchronization.html" title="Synchronization">Synchronization</a>
</h2></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts">Mutex Concepts</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks">Lock Types</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.lock_functions">Lock functions</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types">Mutex Types</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref">Condition Variables</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.once">One-time Initialization</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.barriers">Barriers</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures">Futures</a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.mutex_concepts"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts" title="Mutex Concepts">Mutex Concepts</a>
</h3></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.lockable"><code class="computeroutput"><span class="identifier">Lockable</span></code> Concept</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> Concept</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable"><code class="computeroutput"><span class="identifier">SharedLockable</span></code> Concept</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable"><code class="computeroutput"><span class="identifier">UpgradeLockable</span></code> Concept</a></span></dt>
</dl></div>
<p>
A mutex object facilitates protection against data races and allows thread-safe
synchronization of data between threads. A thread obtains ownership of a
mutex object by calling one of the lock functions and relinquishes ownership
by calling the corresponding unlock function. Mutexes may be either recursive
or non-recursive, and may grant simultaneous ownership to one or many threads.
<span class="bold"><strong>Boost.Thread</strong></span> supplies recursive and non-recursive
mutexes with exclusive ownership semantics, along with a shared ownership
(multiple-reader / single-writer) mutex.
</p>
<p>
<span class="bold"><strong>Boost.Thread</strong></span> supports four basic concepts
for lockable objects: <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a>, <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code></a>, <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable" title="SharedLockable Concept"><code class="computeroutput"><span class="identifier">SharedLockable</span></code></a> and <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable" title="UpgradeLockable Concept"><code class="computeroutput"><span class="identifier">UpgradeLockable</span></code></a>. Each mutex type
implements one or more of these concepts, as do the various lock types.
</p>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_concepts.lockable"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> Concept</a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">()</span></code></a></span></dt>
</dl></div>
<p>
The <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a> models exclusive
ownership. A type that implements the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a> shall provide
the following member functions:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span></code></a>
</li>
</ul></div>
<p>
Lock ownership acquired through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
must be released through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.lockable.lock"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
The current thread blocks until ownership can be obtained for the
current thread.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread owns <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.lockable.try_lock"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Attempt to obtain ownership for the current thread without blocking.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if ownership
was obtained for the current thread, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
If the call returns <code class="computeroutput"><span class="keyword">true</span></code>,
the current thread owns the <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.lockable.unlock"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread owns <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Releases ownership by the current thread.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread no longer owns <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_concepts.timed_lockable"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> Concept</a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock_duration"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">DurationType</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">DurationType</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">)</span></code></a></span></dt>
</dl></div>
<p>
The <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a> refines
the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a> to add support
for timeouts when trying to acquire the lock.
</p>
<p>
A type that implements the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a> shall meet
the requirements of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a>. In addition,
the following member functions must be provided:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">);</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock_duration" title="template<typename DurationType> bool timed_lock(DurationType const& rel_time)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">DurationType</span><span class="special">></span> <span class="keyword">bool</span>
<span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">DurationType</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">);</span></code></a>
</li>
</ul></div>
<p>
Lock ownership acquired through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>
must be released through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.timed_lockable.timed_lock"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Attempt to obtain ownership for the current thread. Blocks until
ownership can be obtained, or the specified time is reached. If
the specified time has already passed, behaves as <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if ownership
was obtained for the current thread, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
If the call returns <code class="computeroutput"><span class="keyword">true</span></code>,
the current thread owns <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.timed_lockable.timed_lock_duration"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock_duration" title="template<typename DurationType> bool timed_lock(DurationType const& rel_time)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">DurationType</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">DurationType</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
As-if <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">get_system_time</span><span class="special">()+</span><span class="identifier">rel_time</span><span class="special">)</span></code></a>.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_concepts.shared_lockable"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable" title="SharedLockable Concept"><code class="computeroutput"><span class="identifier">SharedLockable</span></code> Concept</a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.lock_shared"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock_shared</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">try_lock_shared</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_lock_shared</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.unlock_shared"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_shared</span><span class="special">()</span></code></a></span></dt>
</dl></div>
<p>
The <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable" title="SharedLockable Concept"><code class="computeroutput"><span class="identifier">SharedLockable</span></code> concept</a> is a refinement
of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a> that allows
for <span class="emphasis"><em>shared ownership</em></span> as well as <span class="emphasis"><em>exclusive
ownership</em></span>. This is the standard multiple-reader / single-write
model: at most one thread can have exclusive ownership, and if any thread
does have exclusive ownership, no other threads can have shared or exclusive
ownership. Alternatively, many threads may have shared ownership.
</p>
<p>
For a type to implement the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable" title="SharedLockable Concept"><code class="computeroutput"><span class="identifier">SharedLockable</span></code> concept</a>, as well
as meeting the requirements of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a>, it must
also provide the following member functions:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.lock_shared" title="void lock_shared()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock_shared</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared" title="bool try_lock_shared()"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">try_lock_shared</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.unlock_shared" title="void unlock_shared()"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">unlock_shared</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared" title="bool timed_lock_shared(boost::system_time const& abs_time)"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_lock_shared</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">);</span></code></a>
</li>
</ul></div>
<p>
Lock ownership acquired through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.lock_shared" title="void lock_shared()"><code class="computeroutput"><span class="identifier">lock_shared</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared" title="bool try_lock_shared()"><code class="computeroutput"><span class="identifier">try_lock_shared</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared" title="bool timed_lock_shared(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock_shared</span><span class="special">()</span></code></a>
must be released through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.unlock_shared" title="void unlock_shared()"><code class="computeroutput"><span class="identifier">unlock_shared</span><span class="special">()</span></code></a>.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.shared_lockable.lock_shared"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.lock_shared" title="void lock_shared()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock_shared</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
The current thread blocks until shared ownership can be obtained
for the current thread.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread has shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared" title="bool try_lock_shared()"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">try_lock_shared</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Attempt to obtain shared ownership for the current thread without
blocking.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if shared ownership
was obtained for the current thread, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
If the call returns <code class="computeroutput"><span class="keyword">true</span></code>,
the current thread has shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared" title="bool timed_lock_shared(boost::system_time const& abs_time)"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_lock_shared</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Attempt to obtain shared ownership for the current thread. Blocks
until shared ownership can be obtained, or the specified time is
reached. If the specified time has already passed, behaves as
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared" title="bool try_lock_shared()"><code class="computeroutput"><span class="identifier">try_lock_shared</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if shared ownership
was acquired for the current thread, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
If the call returns <code class="computeroutput"><span class="keyword">true</span></code>,
the current thread has shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.shared_lockable.unlock_shared"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.unlock_shared" title="void unlock_shared()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_shared</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread has shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Releases shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> by the current thread.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread no longer has shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_concepts.upgrade_lockable"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable" title="UpgradeLockable Concept"><code class="computeroutput"><span class="identifier">UpgradeLockable</span></code> Concept</a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.lock_upgrade"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock_upgrade</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock_shared"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock_shared</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_and_lock_upgrade"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_and_lock_upgrade</span><span class="special">()</span></code></a></span></dt>
</dl></div>
<p>
The <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable" title="UpgradeLockable Concept"><code class="computeroutput"><span class="identifier">UpgradeLockable</span></code> concept</a> is a refinement
of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable" title="SharedLockable Concept"><code class="computeroutput"><span class="identifier">SharedLockable</span></code> concept</a> that allows
for <span class="emphasis"><em>upgradable ownership</em></span> as well as <span class="emphasis"><em>shared
ownership</em></span> and <span class="emphasis"><em>exclusive ownership</em></span>. This
is an extension to the multiple-reader / single-write model provided by
the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable" title="SharedLockable Concept"><code class="computeroutput"><span class="identifier">SharedLockable</span></code> concept</a>: a single
thread may have <span class="emphasis"><em>upgradable ownership</em></span> at the same time
as others have <span class="emphasis"><em>shared ownership</em></span>. The thread with
<span class="emphasis"><em>upgradable ownership</em></span> may at any time attempt to upgrade
that ownership to <span class="emphasis"><em>exclusive ownership</em></span>. If no other
threads have shared ownership, the upgrade is completed immediately, and
the thread now has <span class="emphasis"><em>exclusive ownership</em></span>, which must
be relinquished by a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>,
just as if it had been acquired by a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>.
</p>
<p>
If a thread with <span class="emphasis"><em>upgradable ownership</em></span> tries to upgrade
whilst other threads have <span class="emphasis"><em>shared ownership</em></span>, the attempt
will fail and the thread will block until <span class="emphasis"><em>exclusive ownership</em></span>
can be acquired.
</p>
<p>
Ownership can also be <span class="emphasis"><em>downgraded</em></span> as well as <span class="emphasis"><em>upgraded</em></span>:
exclusive ownership of an implementation of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable" title="UpgradeLockable Concept"><code class="computeroutput"><span class="identifier">UpgradeLockable</span></code> concept</a> can be
downgraded to upgradable ownership or shared ownership, and upgradable
ownership can be downgraded to plain shared ownership.
</p>
<p>
For a type to implement the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable" title="UpgradeLockable Concept"><code class="computeroutput"><span class="identifier">UpgradeLockable</span></code> concept</a>, as well
as meeting the requirements of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable" title="SharedLockable Concept"><code class="computeroutput"><span class="identifier">SharedLockable</span></code> concept</a>, it must
also provide the following member functions:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.lock_upgrade" title="void lock_upgrade()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock_upgrade</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade" title="void unlock_upgrade()"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">unlock_upgrade</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock" title="void unlock_upgrade_and_lock()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_and_lock_upgrade" title="void unlock_and_lock_upgrade()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_and_lock_upgrade</span><span class="special">();</span></code></a>
</li>
<li class="listitem">
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock_shared" title="void unlock_upgrade_and_lock_shared()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock_shared</span><span class="special">();</span></code></a>
</li>
</ul></div>
<p>
Lock ownership acquired through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.lock_upgrade" title="void lock_upgrade()"><code class="computeroutput"><span class="identifier">lock_upgrade</span><span class="special">()</span></code></a>
must be released through a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade" title="void unlock_upgrade()"><code class="computeroutput"><span class="identifier">unlock_upgrade</span><span class="special">()</span></code></a>.
If the ownership type is changed through a call to one of the <code class="computeroutput"><span class="identifier">unlock_xxx_and_lock_yyy</span><span class="special">()</span></code>
functions, ownership must be released through a call to the unlock function
corresponding to the new level of ownership.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.upgrade_lockable.lock_upgrade"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.lock_upgrade" title="void lock_upgrade()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">lock_upgrade</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
The current thread blocks until upgrade ownership can be obtained
for the current thread.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread has upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade" title="void unlock_upgrade()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread has upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Releases upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> by the current thread.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread no longer has upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock" title="void unlock_upgrade_and_lock()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread has upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically releases upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> by the current thread and acquires
exclusive ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>. If any other threads have
shared ownership, blocks until exclusive ownership can be acquired.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread has exclusive ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock_shared"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade_and_lock_shared" title="void unlock_upgrade_and_lock_shared()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock_shared</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread has upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically releases upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> by the current thread and acquires
shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> without blocking.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread has shared ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_concepts.upgrade_lockable.unlock_and_lock_upgrade"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_and_lock_upgrade" title="void unlock_and_lock_upgrade()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">unlock_and_lock_upgrade</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread has exclusive ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically releases exclusive ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> by the current thread and acquires
upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> without blocking.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
The current thread has upgrade ownership of <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing
</p></dd>
</dl>
</div>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.locks"></a><a class="link" href="synchronization.html#thread.synchronization.locks" title="Lock Types">Lock Types</a>
</h3></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.lock_tags">Lock option
tags</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.lock_guard">Class template
<code class="computeroutput"><span class="identifier">lock_guard</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock">Class template
<code class="computeroutput"><span class="identifier">unique_lock</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock">Class template
<code class="computeroutput"><span class="identifier">shared_lock</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.upgrade_lock">Class template
<code class="computeroutput"><span class="identifier">upgrade_lock</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.upgrade_to_unique_lock">Class
template <code class="computeroutput"><span class="identifier">upgrade_to_unique_lock</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.scoped_try_lock">Mutex-specific
class <code class="computeroutput"><span class="identifier">scoped_try_lock</span></code></a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.locks.lock_tags"></a><a class="link" href="synchronization.html#thread.synchronization.locks.lock_tags" title="Lock option tags">Lock option
tags</a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">locks</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">struct</span> <span class="identifier">defer_lock_t</span> <span class="special">{};</span>
<span class="keyword">struct</span> <span class="identifier">try_to_lock_t</span> <span class="special">{};</span>
<span class="keyword">struct</span> <span class="identifier">adopt_lock_t</span> <span class="special">{};</span>
<span class="keyword">const</span> <span class="identifier">defer_lock_t</span> <span class="identifier">defer_lock</span><span class="special">;</span>
<span class="keyword">const</span> <span class="identifier">try_to_lock_t</span> <span class="identifier">try_to_lock</span><span class="special">;</span>
<span class="keyword">const</span> <span class="identifier">adopt_lock_t</span> <span class="identifier">adopt_lock</span><span class="special">;</span>
</pre>
<p>
These tags are used in scoped locks constructors to specify a specific
behavior.
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
<code class="computeroutput"><span class="identifier">defer_lock_t</span></code>: is used
to construct the scoped lock without locking it.
</li>
<li class="listitem">
<code class="computeroutput"><span class="identifier">try_to_lock_t</span></code>: is used
to construct the scoped lock trying to lock it.
</li>
<li class="listitem">
<code class="computeroutput"><span class="identifier">adopt_lock_t</span></code>: is used
to construct the scoped lock without locking it but adopting ownership.
</li>
</ul></div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.locks.lock_guard"></a><a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard" title="Class template lock_guard">Class template
<code class="computeroutput"><span class="identifier">lock_guard</span></code></a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.lock_guard.constructor"><code class="computeroutput"><span class="identifier">lock_guard</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.lock_guard.constructor_adopt"><code class="computeroutput"><span class="identifier">lock_guard</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.lock_guard.destructor"><code class="computeroutput"><span class="special">~</span><span class="identifier">lock_guard</span><span class="special">()</span></code></a></span></dt>
</dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">locks</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">lock_guard</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="keyword">explicit</span> <span class="identifier">lock_guard</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">);</span>
<span class="identifier">lock_guard</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">);</span>
<span class="special">~</span><span class="identifier">lock_guard</span><span class="special">();</span>
<span class="special">};</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard" title="Class template lock_guard"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lock_guard</span></code></a>
is very simple: on construction it acquires ownership of the implementation
of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a> supplied as the
constructor parameter. On destruction, the ownership is released. This
provides simple RAII-style locking of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object, to facilitate
exception-safe locking and unlocking. In addition, the <a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard.constructor_adopt" title="lock_guard(Lockable & m,boost::adopt_lock_t)"><code class="computeroutput"><span class="identifier">lock_guard</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">)</span></code>
constructor</a> allows the <a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard" title="Class template lock_guard"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lock_guard</span></code></a> object to take ownership
of a lock already held by the current thread.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.lock_guard.constructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard.constructor" title="lock_guard(Lockable & m)"><code class="computeroutput"><span class="identifier">lock_guard</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exception thrown by the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code></a>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.lock_guard.constructor_adopt"></a><a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard.constructor_adopt" title="lock_guard(Lockable & m,boost::adopt_lock_t)"><code class="computeroutput"><span class="identifier">lock_guard</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread owns a lock on <code class="computeroutput"><span class="identifier">m</span></code>
equivalent to one obtained by a call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Takes ownership of the lock state of <code class="computeroutput"><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.lock_guard.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard.destructor" title="~lock_guard()"><code class="computeroutput"><span class="special">~</span><span class="identifier">lock_guard</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">unlock</span><span class="special">()</span></code></a>
on the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object passed
to the constructor.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.locks.unique_lock"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock">Class template
<code class="computeroutput"><span class="identifier">unique_lock</span></code></a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.defaultconstructor"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.constructor"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_adopt"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_defer"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">defer_lock_t</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_try"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">try_to_lock_t</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_abs_time"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.destructor"><code class="computeroutput"><span class="special">~</span><span class="identifier">unique_lock</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.mutex"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">mutex</span><span class="special">()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.bool_conversion"><code class="computeroutput"><span class="keyword">operator</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="keyword">bool</span><span class="special">-</span><span class="identifier">type</span><span class="special">()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.operator_not"><code class="computeroutput"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.unique_lock.release"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">release</span><span class="special">()</span></code></a></span></dt>
</dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">locks</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">unique_lock</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">unique_lock</span><span class="special">();</span>
<span class="keyword">explicit</span> <span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">);</span>
<span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">adopt_lock_t</span><span class="special">);</span>
<span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">defer_lock_t</span><span class="special">);</span>
<span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">try_to_lock_t</span><span class="special">);</span>
<span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">target_time</span><span class="special">);</span>
<span class="special">~</span><span class="identifier">unique_lock</span><span class="special">();</span>
<span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">operator</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">>();</span>
<span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">move</span><span class="special">();</span>
<span class="identifier">unique_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">unique_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">unique_lock</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">TimeDuration</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">TimeDuration</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">relative_time</span><span class="special">);</span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(::</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">absolute_time</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">operator</span> <span class="emphasis"><em>unspecified-bool-type</em></span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">mutex</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">release</span><span class="special">();</span>
<span class="special">};</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a> is more complex than
<a class="link" href="synchronization.html#thread.synchronization.locks.lock_guard" title="Class template lock_guard"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">lock_guard</span></code></a>:
not only does it provide for RAII-style locking, it also allows for deferring
acquiring the lock until the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
member function is called explicitly, or trying to acquire the lock in
a non-blocking fashion, or with a timeout. Consequently, <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
is only called in the destructor if the lock object has locked the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object, or otherwise
adopted a lock on the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object.
</p>
<p>
Specializations of <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a> model the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a> if the supplied
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> type itself models <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a> (e.g. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">timed_mutex</span><span class="special">></span></code>),
or the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a> otherwise (e.g.
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">></span></code>).
</p>
<p>
An instance of <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a> is said to <span class="emphasis"><em>own</em></span>
the lock state of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> <code class="computeroutput"><span class="identifier">m</span></code>
if <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns a pointer to <code class="computeroutput"><span class="identifier">m</span></code>
and <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. If an object
that <span class="emphasis"><em>owns</em></span> the lock state of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object is destroyed,
then the destructor will invoke <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()-></span><span class="identifier">unlock</span><span class="special">()</span></code></a>.
</p>
<p>
The member functions of <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a> are not thread-safe.
In particular, <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a> is intended to model
the ownership of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object by a particular
thread, and the member functions that release ownership of the lock state
(including the destructor) must be called by the same thread that acquired
ownership of the lock state.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.defaultconstructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.defaultconstructor" title="unique_lock()"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Creates a lock object with no associated mutex.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="identifier">NULL</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.constructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.constructor" title="unique_lock(Lockable & m)"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exception thrown by the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code></a>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.constructor_adopt"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_adopt" title="unique_lock(Lockable & m,boost::adopt_lock_t)"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread owns an exclusive lock on <code class="computeroutput"><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Takes ownership of the lock state of <code class="computeroutput"><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.constructor_defer"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_defer" title="unique_lock(Lockable & m,boost::defer_lock_t)"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">defer_lock_t</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.constructor_try"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_try" title="unique_lock(Lockable & m,boost::try_to_lock_t)"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">try_to_lock_t</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">try_lock</span><span class="special">()</span></code></a>,
and takes ownership of the lock state if the call returns <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
If the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
returned <code class="computeroutput"><span class="keyword">true</span></code>, then
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>, otherwise
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.constructor_abs_time"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.constructor_abs_time" title="unique_lock(Lockable & m,boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">unique_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">abs_time</span><span class="special">)</span></code></a>,
and takes ownership of the lock state if the call returns <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
If the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>
returned <code class="computeroutput"><span class="keyword">true</span></code>, then
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>, otherwise
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">abs_time</span><span class="special">)</span></code></a>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.destructor" title="~unique_lock()"><code class="computeroutput"><span class="special">~</span><span class="identifier">unique_lock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Invokes <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a><code class="computeroutput"><span class="special">-></span></code> <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
if <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.owns_lock"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if the <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
owns the lock on the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.mutex"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">mutex</span><span class="special">()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
A pointer to the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
or <code class="computeroutput"><span class="identifier">NULL</span></code> if there
is no such object.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.bool_conversion"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.bool_conversion" title="operator unspecified-bool-type() const"><code class="computeroutput"><span class="keyword">operator</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="keyword">bool</span><span class="special">-</span><span class="identifier">type</span><span class="special">()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
If <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
would return <code class="computeroutput"><span class="keyword">true</span></code>,
a value that evaluates to <code class="computeroutput"><span class="keyword">true</span></code>
in boolean contexts, otherwise a value that evaluates to <code class="computeroutput"><span class="keyword">false</span></code> in boolean contexts.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.operator_not"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.operator_not" title="bool operator!() const"><code class="computeroutput"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="special">!</span></code> <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.unique_lock.release"></a><a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.release" title="Lockable* release()"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">release</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
The association between <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> and the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object is removed,
without affecting the lock state of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object. If <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
would have returned <code class="computeroutput"><span class="keyword">true</span></code>,
it is the responsibility of the calling code to ensure that the
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> is correctly
unlocked.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
A pointer to the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
at the point of the call, or <code class="computeroutput"><span class="identifier">NULL</span></code>
if there is no such object.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is no longer associated with any <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="identifier">NULL</span></code> and
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.locks.shared_lock"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock" title="Class template shared_lock">Class template
<code class="computeroutput"><span class="identifier">shared_lock</span></code></a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.defaultconstructor"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.constructor"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_adopt"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_defer"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">defer_lock_t</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_try"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">try_to_lock_t</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_abs_time"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.destructor"><code class="computeroutput"><span class="special">~</span><span class="identifier">shared_lock</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.mutex"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">mutex</span><span class="special">()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.bool_conversion"><code class="computeroutput"><span class="keyword">operator</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="keyword">bool</span><span class="special">-</span><span class="identifier">type</span><span class="special">()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.operator_not"><code class="computeroutput"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.locks.shared_lock.release"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">release</span><span class="special">()</span></code></a></span></dt>
</dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">locks</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">shared_lock</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">shared_lock</span><span class="special">();</span>
<span class="keyword">explicit</span> <span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">adopt_lock_t</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">defer_lock_t</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">try_to_lock_t</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">target_time</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">shared_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="special">~</span><span class="identifier">shared_lock</span><span class="special">();</span>
<span class="keyword">operator</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">shared_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">>();</span>
<span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">shared_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">move</span><span class="special">();</span>
<span class="identifier">shared_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">shared_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">shared_lock</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">target_time</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">operator</span> <span class="emphasis"><em>unspecified-bool-type</em></span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
Like <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a>, <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock" title="Class template shared_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_lock</span></code></a> models the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a>, but rather than
acquiring unique ownership of the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object, locking an instance
of <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock" title="Class template shared_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_lock</span></code></a> acquires shared ownership.
</p>
<p>
Like <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a>, not only does it
provide for RAII-style locking, it also allows for deferring acquiring
the lock until the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
member function is called explicitly, or trying to acquire the lock in
a non-blocking fashion, or with a timeout. Consequently, <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
is only called in the destructor if the lock object has locked the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object, or otherwise
adopted a lock on the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object.
</p>
<p>
An instance of <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock" title="Class template shared_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_lock</span></code></a> is said to <span class="emphasis"><em>own</em></span>
the lock state of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> <code class="computeroutput"><span class="identifier">m</span></code>
if <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns a pointer to <code class="computeroutput"><span class="identifier">m</span></code>
and <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. If an object
that <span class="emphasis"><em>owns</em></span> the lock state of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object is destroyed,
then the destructor will invoke <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.unlock_shared" title="void unlock_shared()"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()-></span><span class="identifier">unlock_shared</span><span class="special">()</span></code></a>.
</p>
<p>
The member functions of <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock" title="Class template shared_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_lock</span></code></a> are not thread-safe.
In particular, <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock" title="Class template shared_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_lock</span></code></a> is intended to model
the shared ownership of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object by a particular
thread, and the member functions that release ownership of the lock state
(including the destructor) must be called by the same thread that acquired
ownership of the lock state.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.defaultconstructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.defaultconstructor" title="shared_lock()"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Creates a lock object with no associated mutex.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="identifier">NULL</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.constructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.constructor" title="shared_lock(Lockable & m)"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.lock_shared" title="void lock_shared()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock_shared</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exception thrown by the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.lock_shared" title="void lock_shared()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock_shared</span><span class="special">()</span></code></a>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.constructor_adopt"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_adopt" title="shared_lock(Lockable & m,boost::adopt_lock_t)"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">adopt_lock_t</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
The current thread owns an exclusive lock on <code class="computeroutput"><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Takes ownership of the lock state of <code class="computeroutput"><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.constructor_defer"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_defer" title="shared_lock(Lockable & m,boost::defer_lock_t)"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">defer_lock_t</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.constructor_try"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_try" title="shared_lock(Lockable & m,boost::try_to_lock_t)"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">try_to_lock_t</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared" title="bool try_lock_shared()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">try_lock_shared</span><span class="special">()</span></code></a>,
and takes ownership of the lock state if the call returns <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
If the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared" title="bool try_lock_shared()"><code class="computeroutput"><span class="identifier">try_lock_shared</span><span class="special">()</span></code></a>
returned <code class="computeroutput"><span class="keyword">true</span></code>, then
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>, otherwise
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.constructor_abs_time"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.constructor_abs_time" title="shared_lock(Lockable & m,boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">shared_lock</span><span class="special">(</span><span class="identifier">Lockable</span> <span class="special">&</span>
<span class="identifier">m</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Stores a reference to <code class="computeroutput"><span class="identifier">m</span></code>.
Invokes <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared" title="bool timed_lock_shared(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">abs_time</span><span class="special">)</span></code></a>,
and takes ownership of the lock state if the call returns <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="special">&</span><span class="identifier">m</span></code>.
If the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared" title="bool timed_lock_shared(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock_shared</span><span class="special">()</span></code></a>
returned <code class="computeroutput"><span class="keyword">true</span></code>, then
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>, otherwise
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by the call to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared" title="bool timed_lock_shared(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">abs_time</span><span class="special">)</span></code></a>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.destructor" title="~shared_lock()"><code class="computeroutput"><span class="special">~</span><span class="identifier">shared_lock</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Invokes <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a><code class="computeroutput"><span class="special">-></span></code> <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.unlock_shared" title="void unlock_shared()"><code class="computeroutput"><span class="identifier">unlock_shared</span><span class="special">()</span></code></a>
if <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.owns_lock"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if the <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
owns the lock on the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.mutex"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">mutex</span><span class="special">()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
A pointer to the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
or <code class="computeroutput"><span class="identifier">NULL</span></code> if there
is no such object.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.bool_conversion"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.bool_conversion" title="operator unspecified-bool-type() const"><code class="computeroutput"><span class="keyword">operator</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="keyword">bool</span><span class="special">-</span><span class="identifier">type</span><span class="special">()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
If <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
would return <code class="computeroutput"><span class="keyword">true</span></code>,
a value that evaluates to <code class="computeroutput"><span class="keyword">true</span></code>
in boolean contexts, otherwise a value that evaluates to <code class="computeroutput"><span class="keyword">false</span></code> in boolean contexts.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.operator_not"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.operator_not" title="bool operator!() const"><code class="computeroutput"><span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="special">!</span></code> <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.locks.shared_lock.release"></a><a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.release" title="Lockable* release()"><code class="computeroutput"><span class="identifier">Lockable</span><span class="special">*</span> <span class="identifier">release</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
The association between <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> and the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object is removed,
without affecting the lock state of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object. If <a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
would have returned <code class="computeroutput"><span class="keyword">true</span></code>,
it is the responsibility of the calling code to ensure that the
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> is correctly
unlocked.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
A pointer to the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
at the point of the call, or <code class="computeroutput"><span class="identifier">NULL</span></code>
if there is no such object.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is no longer associated with any <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object. <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="identifier">NULL</span></code> and
<a class="link" href="synchronization.html#thread.synchronization.locks.shared_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code>.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.locks.upgrade_lock"></a><a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock">Class template
<code class="computeroutput"><span class="identifier">upgrade_lock</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">locks</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">upgrade_lock</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="keyword">explicit</span> <span class="identifier">upgrade_lock</span><span class="special">(</span><span class="identifier">Lockable</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">);</span>
<span class="identifier">upgrade_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">upgrade_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="special">~</span><span class="identifier">upgrade_lock</span><span class="special">();</span>
<span class="keyword">operator</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">>();</span>
<span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">move</span><span class="special">();</span>
<span class="identifier">upgrade_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">upgrade_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">upgrade_lock</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">operator</span> <span class="emphasis"><em>unspecified-bool-type</em></span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
Like <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a>, <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_lock</span></code></a> models the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a>, but rather than
acquiring unique ownership of the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object, locking an instance
of <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_lock</span></code></a> acquires upgrade
ownership.
</p>
<p>
Like <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span></code></a>, not only does it
provide for RAII-style locking, it also allows for deferring acquiring
the lock until the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
member function is called explicitly, or trying to acquire the lock in
a non-blocking fashion, or with a timeout. Consequently, <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
is only called in the destructor if the lock object has locked the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object, or otherwise
adopted a lock on the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object.
</p>
<p>
An instance of <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_lock</span></code></a> is said to <span class="emphasis"><em>own</em></span>
the lock state of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> <code class="computeroutput"><span class="identifier">m</span></code>
if <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.mutex" title="Lockable* mutex() const"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code></a>
returns a pointer to <code class="computeroutput"><span class="identifier">m</span></code>
and <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock.owns_lock" title="bool owns_lock() const"><code class="computeroutput"><span class="identifier">owns_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. If an object
that <span class="emphasis"><em>owns</em></span> the lock state of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object is destroyed,
then the destructor will invoke <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable.unlock_upgrade" title="void unlock_upgrade()"><code class="computeroutput"><span class="identifier">mutex</span><span class="special">()-></span><span class="identifier">unlock_upgrade</span><span class="special">()</span></code></a>.
</p>
<p>
The member functions of <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_lock</span></code></a> are not thread-safe.
In particular, <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_lock</span></code></a> is intended to model
the upgrade ownership of a <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object by a particular
thread, and the member functions that release ownership of the lock state
(including the destructor) must be called by the same thread that acquired
ownership of the lock state.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.locks.upgrade_to_unique_lock"></a><a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_to_unique_lock" title="Class template upgrade_to_unique_lock">Class
template <code class="computeroutput"><span class="identifier">upgrade_to_unique_lock</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">locks</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Lockable</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">upgrade_to_unique_lock</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="keyword">explicit</span> <span class="identifier">upgrade_to_unique_lock</span><span class="special">(</span><span class="identifier">upgrade_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">>&</span> <span class="identifier">m_</span><span class="special">);</span>
<span class="special">~</span><span class="identifier">upgrade_to_unique_lock</span><span class="special">();</span>
<span class="identifier">upgrade_to_unique_lock</span><span class="special">(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_to_unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">upgrade_to_unique_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">detail</span><span class="special">::</span><span class="identifier">thread_move_t</span><span class="special"><</span><span class="identifier">upgrade_to_unique_lock</span><span class="special"><</span><span class="identifier">Lockable</span><span class="special">></span> <span class="special">></span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">upgrade_to_unique_lock</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">operator</span> <span class="emphasis"><em>unspecified-bool-type</em></span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_to_unique_lock" title="Class template upgrade_to_unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_to_unique_lock</span></code></a> allows
for a temporary upgrade of an <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_lock</span></code></a> to exclusive ownership.
When constructed with a reference to an instance of <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_lock" title="Class template upgrade_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_lock</span></code></a>, if that instance
has upgrade ownership on some <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> object, that ownership
is upgraded to exclusive ownership. When the <a class="link" href="synchronization.html#thread.synchronization.locks.upgrade_to_unique_lock" title="Class template upgrade_to_unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">upgrade_to_unique_lock</span></code></a> instance
is destroyed, the ownership of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> is downgraded back to
<span class="emphasis"><em>upgrade ownership</em></span>.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.locks.scoped_try_lock"></a><a class="link" href="synchronization.html#thread.synchronization.locks.scoped_try_lock" title="Mutex-specific class scoped_try_lock">Mutex-specific
class <code class="computeroutput"><span class="identifier">scoped_try_lock</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="keyword">class</span> <span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span>
<span class="special">{</span>
<span class="keyword">private</span><span class="special">:</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">(</span><span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special"><</span><span class="identifier">MutexType</span><span class="special">>&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special"><</span><span class="identifier">MutexType</span><span class="special">>&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">();</span>
<span class="keyword">explicit</span> <span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">(</span><span class="identifier">MutexType</span><span class="special">&</span> <span class="identifier">m</span><span class="special">);</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">(</span><span class="identifier">MutexType</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">adopt_lock_t</span><span class="special">);</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">(</span><span class="identifier">MutexType</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">defer_lock_t</span><span class="special">);</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">(</span><span class="identifier">MutexType</span><span class="special">&</span> <span class="identifier">m_</span><span class="special">,</span><span class="identifier">try_to_lock_t</span><span class="special">);</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">(</span><span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special"><</span><span class="identifier">MutexType</span><span class="special">>&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special"><</span><span class="identifier">MutexType</span><span class="special">>&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">MutexType</span><span class="special">::</span><span class="identifier">scoped_try_lock</span><span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">owns_lock</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="identifier">MutexType</span><span class="special">*</span> <span class="identifier">mutex</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="identifier">MutexType</span><span class="special">*</span> <span class="identifier">release</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">!()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="emphasis"><em>unspecified-bool-type</em></span> <span class="identifier">bool_type</span><span class="special">;</span>
<span class="keyword">operator</span> <span class="identifier">bool_type</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
The member typedef <code class="computeroutput"><span class="identifier">scoped_try_lock</span></code>
is provided for each distinct <code class="computeroutput"><span class="identifier">MutexType</span></code>
as a typedef to a class with the preceding definition. The semantics of
each constructor and member function are identical to those of <a class="link" href="synchronization.html#thread.synchronization.locks.unique_lock" title="Class template unique_lock"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">MutexType</span><span class="special">></span></code></a>
for the same <code class="computeroutput"><span class="identifier">MutexType</span></code>,
except that the constructor that takes a single reference to a mutex will
call <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">try_lock</span><span class="special">()</span></code></a> rather than <code class="computeroutput"><span class="identifier">m</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code>.
</p>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.lock_functions"></a><a class="link" href="synchronization.html#thread.synchronization.lock_functions" title="Lock functions">Lock functions</a>
</h3></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.lock_functions.lock_multiple">Non-member
function <code class="computeroutput"><span class="identifier">lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">,...)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.lock_functions.lock_range">Non-member
function <code class="computeroutput"><span class="identifier">lock</span><span class="special">(</span><span class="identifier">begin</span><span class="special">,</span><span class="identifier">end</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.lock_functions.try_lock_multiple">Non-member
function <code class="computeroutput"><span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">,...)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.lock_functions.try_lock_range">Non-member
function <code class="computeroutput"><span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">begin</span><span class="special">,</span><span class="identifier">end</span><span class="special">)</span></code></a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.lock_functions.lock_multiple"></a><a class="link" href="synchronization.html#thread.synchronization.lock_functions.lock_multiple" title="Non-member function lock(Lockable1,Lockable2,...)">Non-member
function <code class="computeroutput"><span class="identifier">lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">,...)</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable3</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">,</span><span class="identifier">Lockable3</span><span class="special">&</span> <span class="identifier">l3</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable4</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">,</span><span class="identifier">Lockable3</span><span class="special">&</span> <span class="identifier">l3</span><span class="special">,</span><span class="identifier">Lockable4</span><span class="special">&</span> <span class="identifier">l4</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable4</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable5</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">,</span><span class="identifier">Lockable3</span><span class="special">&</span> <span class="identifier">l3</span><span class="special">,</span><span class="identifier">Lockable4</span><span class="special">&</span> <span class="identifier">l4</span><span class="special">,</span><span class="identifier">Lockable5</span><span class="special">&</span> <span class="identifier">l5</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Locks the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects supplied
as arguments in an unspecified and indeterminate order in a way that
avoids deadlock. It is safe to call this function concurrently from
multiple threads with the same mutexes (or other lockable objects)
in different orders without risk of deadlock. If any of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
operations on the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects throws
an exception any locks acquired by the function will be released
before the function exits.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by calling <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
on the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
All the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects are locked
by the calling thread.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.lock_functions.lock_range"></a><a class="link" href="synchronization.html#thread.synchronization.lock_functions.lock_range" title="Non-member function lock(begin,end)">Non-member
function <code class="computeroutput"><span class="identifier">lock</span><span class="special">(</span><span class="identifier">begin</span><span class="special">,</span><span class="identifier">end</span><span class="special">)</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">ForwardIterator</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">(</span><span class="identifier">ForwardIterator</span> <span class="identifier">begin</span><span class="special">,</span><span class="identifier">ForwardIterator</span> <span class="identifier">end</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Preconditions:</span></dt>
<dd><p>
The <code class="computeroutput"><span class="identifier">value_type</span></code> of
<code class="computeroutput"><span class="identifier">ForwardIterator</span></code> must
implement the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a>
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Locks all the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects in the
supplied range in an unspecified and indeterminate order in a way
that avoids deadlock. It is safe to call this function concurrently
from multiple threads with the same mutexes (or other lockable objects)
in different orders without risk of deadlock. If any of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
operations on the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects in the
supplied range throws an exception any locks acquired by the function
will be released before the function exits.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by calling <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
on the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
All the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects in the
supplied range are locked by the calling thread.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.lock_functions.try_lock_multiple"></a><a class="link" href="synchronization.html#thread.synchronization.lock_functions.try_lock_multiple" title="Non-member function try_lock(Lockable1,Lockable2,...)">Non-member
function <code class="computeroutput"><span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">,...)</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">></span>
<span class="keyword">int</span> <span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable3</span><span class="special">></span>
<span class="keyword">int</span> <span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">,</span><span class="identifier">Lockable3</span><span class="special">&</span> <span class="identifier">l3</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable4</span><span class="special">></span>
<span class="keyword">int</span> <span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">,</span><span class="identifier">Lockable3</span><span class="special">&</span> <span class="identifier">l3</span><span class="special">,</span><span class="identifier">Lockable4</span><span class="special">&</span> <span class="identifier">l4</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Lockable1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable4</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">Lockable5</span><span class="special">></span>
<span class="keyword">int</span> <span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">Lockable1</span><span class="special">&</span> <span class="identifier">l1</span><span class="special">,</span><span class="identifier">Lockable2</span><span class="special">&</span> <span class="identifier">l2</span><span class="special">,</span><span class="identifier">Lockable3</span><span class="special">&</span> <span class="identifier">l3</span><span class="special">,</span><span class="identifier">Lockable4</span><span class="special">&</span> <span class="identifier">l4</span><span class="special">,</span><span class="identifier">Lockable5</span><span class="special">&</span> <span class="identifier">l5</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd>
<p>
Calls <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
on each of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects supplied
as arguments. If any of the calls to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code> then all
locks acquired are released and the zero-based index of the failed
lock is returned.
</p>
<p>
If any of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
operations on the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects throws
an exception any locks acquired by the function will be released
before the function exits.
</p>
</dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="special">-</span><span class="number">1</span></code>
if all the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects are now
locked by the calling thread, the zero-based index of the object
which could not be locked otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by calling <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
on the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
If the function returns <code class="computeroutput"><span class="special">-</span><span class="number">1</span></code>, all the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects are locked
by the calling thread. Otherwise any locks acquired by this function
will have been released.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.lock_functions.try_lock_range"></a><a class="link" href="synchronization.html#thread.synchronization.lock_functions.try_lock_range" title="Non-member function try_lock(begin,end)">Non-member
function <code class="computeroutput"><span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">begin</span><span class="special">,</span><span class="identifier">end</span><span class="special">)</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">ForwardIterator</span><span class="special">></span>
<span class="identifier">ForwardIterator</span> <span class="identifier">try_lock</span><span class="special">(</span><span class="identifier">ForwardIterator</span> <span class="identifier">begin</span><span class="special">,</span><span class="identifier">ForwardIterator</span> <span class="identifier">end</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Preconditions:</span></dt>
<dd><p>
The <code class="computeroutput"><span class="identifier">value_type</span></code> of
<code class="computeroutput"><span class="identifier">ForwardIterator</span></code> must
implement the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a>
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd>
<p>
Calls <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
on each of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects in the
supplied range. If any of the calls to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">false</span></code> then all
locks acquired are released and an iterator referencing the failed
lock is returned.
</p>
<p>
If any of the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
operations on the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects throws
an exception any locks acquired by the function will be released
before the function exits.
</p>
</dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">end</span></code> if all the supplied
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects are now
locked by the calling thread, an iterator referencing the object
which could not be locked otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by calling <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
on the supplied <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
If the function returns <code class="computeroutput"><span class="identifier">end</span></code>
then all the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code></a> objects in the
supplied range are locked by the calling thread, otherwise all locks
acquired by the function have been released.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.mutex_types"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types" title="Mutex Types">Mutex Types</a>
</h3></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.mutex">Class <code class="computeroutput"><span class="identifier">mutex</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.try_mutex">Typedef
<code class="computeroutput"><span class="identifier">try_mutex</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.timed_mutex">Class
<code class="computeroutput"><span class="identifier">timed_mutex</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex">Class
<code class="computeroutput"><span class="identifier">recursive_mutex</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.recursive_try_mutex">Typedef
<code class="computeroutput"><span class="identifier">recursive_try_mutex</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.recursive_timed_mutex">Class
<code class="computeroutput"><span class="identifier">recursive_timed_mutex</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.shared_mutex">Class
<code class="computeroutput"><span class="identifier">shared_mutex</span></code></a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_types.mutex"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.mutex" title="Class mutex">Class <code class="computeroutput"><span class="identifier">mutex</span></code></a>
</h4></div></div></div>
<div class="toc"><dl><dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.mutex.nativehandle">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a></span></dt></dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">mutex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">mutex</span><span class="special">:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">noncopyable</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">mutex</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">mutex</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
<span class="keyword">typedef</span> <span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">mutex</span><span class="special">></span> <span class="identifier">scoped_lock</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">scoped_try_lock</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.mutex_types.mutex" title="Class mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span></code></a> implements the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a> to provide an
exclusive-ownership mutex. At most one thread can own the lock on a given
instance of <a class="link" href="synchronization.html#thread.synchronization.mutex_types.mutex" title="Class mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span></code></a> at any time. Multiple concurrent
calls to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
and <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
shall be permitted.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_types.mutex.nativehandle"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.mutex.nativehandle" title="Member function native_handle()">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Returns an instance of <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
that can be used with platform-specific APIs to manipulate the
underlying implementation. If no such instance exists, <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code>
and <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
are not present.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_types.try_mutex"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.try_mutex" title="Typedef try_mutex">Typedef
<code class="computeroutput"><span class="identifier">try_mutex</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">mutex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">typedef</span> <span class="identifier">mutex</span> <span class="identifier">try_mutex</span><span class="special">;</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.mutex_types.try_mutex" title="Typedef try_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">try_mutex</span></code></a> is a <code class="computeroutput"><span class="keyword">typedef</span></code>
to <a class="link" href="synchronization.html#thread.synchronization.mutex_types.mutex" title="Class mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span></code></a>, provided for backwards
compatibility with previous releases of boost.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_types.timed_mutex"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.timed_mutex" title="Class timed_mutex">Class
<code class="computeroutput"><span class="identifier">timed_mutex</span></code></a>
</h4></div></div></div>
<div class="toc"><dl><dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.timed_mutex.nativehandle">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a></span></dt></dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">mutex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">timed_mutex</span><span class="special">:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">noncopyable</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">timed_mutex</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">timed_mutex</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">system_time</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">abs_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">TimeDuration</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">TimeDuration</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">relative_time</span><span class="special">);</span>
<span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
<span class="keyword">typedef</span> <span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">timed_mutex</span><span class="special">></span> <span class="identifier">scoped_timed_lock</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">scoped_try_lock</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">scoped_timed_lock</span> <span class="identifier">scoped_lock</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.mutex_types.timed_mutex" title="Class timed_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">timed_mutex</span></code></a> implements the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a> to provide
an exclusive-ownership mutex. At most one thread can own the lock on a
given instance of <a class="link" href="synchronization.html#thread.synchronization.mutex_types.timed_mutex" title="Class timed_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">timed_mutex</span></code></a> at any time. Multiple
concurrent calls to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock_duration" title="template<typename DurationType> bool timed_lock(DurationType const& rel_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>
and <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
shall be permitted.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_types.timed_mutex.nativehandle"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.timed_mutex.nativehandle" title="Member function native_handle()">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Returns an instance of <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
that can be used with platform-specific APIs to manipulate the
underlying implementation. If no such instance exists, <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code>
and <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
are not present.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_types.recursive_mutex"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex" title="Class recursive_mutex">Class
<code class="computeroutput"><span class="identifier">recursive_mutex</span></code></a>
</h4></div></div></div>
<div class="toc"><dl><dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex.nativehandle">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a></span></dt></dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">recursive_mutex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">recursive_mutex</span><span class="special">:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">noncopyable</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">recursive_mutex</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">recursive_mutex</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
<span class="keyword">typedef</span> <span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">recursive_mutex</span><span class="special">></span> <span class="identifier">scoped_lock</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">scoped_try_lock</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex" title="Class recursive_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_mutex</span></code></a> implements the
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable" title="Lockable Concept"><code class="computeroutput"><span class="identifier">Lockable</span></code> concept</a> to provide an
exclusive-ownership recursive mutex. At most one thread can own the lock
on a given instance of <a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex" title="Class recursive_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_mutex</span></code></a> at any time. Multiple
concurrent calls to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
and <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
shall be permitted. A thread that already has exclusive ownership of a
given <a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex" title="Class recursive_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_mutex</span></code></a> instance can call
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
to acquire an additional level of ownership of the mutex. <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
must be called once for each level of ownership acquired by a single thread
before ownership can be acquired by another thread.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_types.recursive_mutex.nativehandle"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex.nativehandle" title="Member function native_handle()">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Returns an instance of <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
that can be used with platform-specific APIs to manipulate the
underlying implementation. If no such instance exists, <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code>
and <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
are not present.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_types.recursive_try_mutex"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_try_mutex" title="Typedef recursive_try_mutex">Typedef
<code class="computeroutput"><span class="identifier">recursive_try_mutex</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">recursive_mutex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">typedef</span> <span class="identifier">recursive_mutex</span> <span class="identifier">recursive_try_mutex</span><span class="special">;</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_try_mutex" title="Typedef recursive_try_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_try_mutex</span></code></a> is a <code class="computeroutput"><span class="keyword">typedef</span></code> to <a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_mutex" title="Class recursive_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_mutex</span></code></a>, provided for
backwards compatibility with previous releases of boost.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_types.recursive_timed_mutex"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_timed_mutex" title="Class recursive_timed_mutex">Class
<code class="computeroutput"><span class="identifier">recursive_timed_mutex</span></code></a>
</h4></div></div></div>
<div class="toc"><dl><dt><span class="section"><a href="synchronization.html#thread.synchronization.mutex_types.recursive_timed_mutex.nativehandle">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a></span></dt></dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">recursive_mutex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">recursive_timed_mutex</span><span class="special">:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">noncopyable</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">recursive_timed_mutex</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">recursive_timed_mutex</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">system_time</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">abs_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">TimeDuration</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">TimeDuration</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">relative_time</span><span class="special">);</span>
<span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
<span class="keyword">typedef</span> <span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">recursive_timed_mutex</span><span class="special">></span> <span class="identifier">scoped_lock</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">unspecified</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">scoped_try_lock</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">scoped_lock</span> <span class="identifier">scoped_timed_lock</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<p>
<a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_timed_mutex" title="Class recursive_timed_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_timed_mutex</span></code></a> implements
the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable" title="TimedLockable Concept"><code class="computeroutput"><span class="identifier">TimedLockable</span></code> concept</a> to provide
an exclusive-ownership recursive mutex. At most one thread can own the
lock on a given instance of <a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_timed_mutex" title="Class recursive_timed_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_timed_mutex</span></code></a> at any time.
Multiple concurrent calls to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock_duration" title="template<typename DurationType> bool timed_lock(DurationType const& rel_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>
and <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
shall be permitted. A thread that already has exclusive ownership of a
given <a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_timed_mutex" title="Class recursive_timed_mutex"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">recursive_timed_mutex</span></code></a> instance
can call <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock_duration" title="template<typename DurationType> bool timed_lock(DurationType const& rel_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>
to acquire an additional level of ownership of the mutex. <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.unlock" title="void unlock()"><code class="computeroutput"><span class="identifier">unlock</span><span class="special">()</span></code></a>
must be called once for each level of ownership acquired by a single thread
before ownership can be acquired by another thread.
</p>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.mutex_types.recursive_timed_mutex.nativehandle"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.recursive_timed_mutex.nativehandle" title="Member function native_handle()">Member
function <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code></a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">native_handle_type</span><span class="special">;</span>
<span class="identifier">native_handle_type</span> <span class="identifier">native_handle</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Returns an instance of <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
that can be used with platform-specific APIs to manipulate the
underlying implementation. If no such instance exists, <code class="computeroutput"><span class="identifier">native_handle</span><span class="special">()</span></code>
and <code class="computeroutput"><span class="identifier">native_handle_type</span></code>
are not present.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.mutex_types.shared_mutex"></a><a class="link" href="synchronization.html#thread.synchronization.mutex_types.shared_mutex" title="Class shared_mutex">Class
<code class="computeroutput"><span class="identifier">shared_mutex</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">shared_mutex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">shared_mutex</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">shared_mutex</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">shared_mutex</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">lock_shared</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock_shared</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">timed_lock_shared</span><span class="special">(</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">unlock_shared</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">try_lock</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">timed_lock</span><span class="special">(</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">unlock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">lock_upgrade</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock_upgrade</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock_and_lock_upgrade</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock_and_lock_shared</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unlock_upgrade_and_lock_shared</span><span class="special">();</span>
<span class="special">};</span>
</pre>
<p>
The class <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_mutex</span></code> provides an implementation
of a multiple-reader / single-writer mutex. It implements the <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.upgrade_lockable" title="UpgradeLockable Concept"><code class="computeroutput"><span class="identifier">UpgradeLockable</span></code> concept</a>.
</p>
<p>
Multiple concurrent calls to <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.lock" title="void lock()"><code class="computeroutput"><span class="identifier">lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.lockable.try_lock" title="bool try_lock()"><code class="computeroutput"><span class="identifier">try_lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.timed_lockable.timed_lock" title="bool timed_lock(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.lock_shared" title="void lock_shared()"><code class="computeroutput"><span class="identifier">lock_shared</span><span class="special">()</span></code></a>,
<a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.try_lock_shared" title="bool try_lock_shared()"><code class="computeroutput"><span class="identifier">try_lock_shared</span><span class="special">()</span></code></a>
and <a class="link" href="synchronization.html#thread.synchronization.mutex_concepts.shared_lockable.timed_lock_shared" title="bool timed_lock_shared(boost::system_time const& abs_time)"><code class="computeroutput"><span class="identifier">timed_lock_shared</span><span class="special">()</span></code></a>
shall be permitted.
</p>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.condvar_ref"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref" title="Condition Variables">Condition Variables</a>
</h3></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable">Class
<code class="computeroutput"><span class="identifier">condition_variable</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any">Class
<code class="computeroutput"><span class="identifier">condition_variable_any</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition">Typedef
<code class="computeroutput"><span class="identifier">condition</span></code></a></span></dt>
</dl></div>
<h5>
<a name="thread.synchronization.condvar_ref.h0"></a>
<span><a name="thread.synchronization.condvar_ref.synopsis"></a></span><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.synopsis">Synopsis</a>
</h5>
<p>
The classes <code class="computeroutput"><span class="identifier">condition_variable</span></code>
and <code class="computeroutput"><span class="identifier">condition_variable_any</span></code>
provide a mechanism for one thread to wait for notification from another
thread that a particular condition has become true. The general usage pattern
is that one thread locks a mutex and then calls <code class="computeroutput"><span class="identifier">wait</span></code>
on an instance of <code class="computeroutput"><span class="identifier">condition_variable</span></code>
or <code class="computeroutput"><span class="identifier">condition_variable_any</span></code>.
When the thread is woken from the wait, then it checks to see if the appropriate
condition is now true, and continues if so. If the condition is not true,
then the thread then calls <code class="computeroutput"><span class="identifier">wait</span></code>
again to resume waiting. In the simplest case, this condition is just a boolean
variable:
</p>
<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">condition_variable</span> <span class="identifier">cond</span><span class="special">;</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span> <span class="identifier">mut</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">data_ready</span><span class="special">;</span>
<span class="keyword">void</span> <span class="identifier">process_data</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">wait_for_data_to_process</span><span class="special">()</span>
<span class="special">{</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">></span> <span class="identifier">lock</span><span class="special">(</span><span class="identifier">mut</span><span class="special">);</span>
<span class="keyword">while</span><span class="special">(!</span><span class="identifier">data_ready</span><span class="special">)</span>
<span class="special">{</span>
<span class="identifier">cond</span><span class="special">.</span><span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock</span><span class="special">);</span>
<span class="special">}</span>
<span class="identifier">process_data</span><span class="special">();</span>
<span class="special">}</span>
</pre>
<p>
Notice that the <code class="computeroutput"><span class="identifier">lock</span></code> is passed
to <code class="computeroutput"><span class="identifier">wait</span></code>: <code class="computeroutput"><span class="identifier">wait</span></code>
will atomically add the thread to the set of threads waiting on the condition
variable, and unlock the mutex. When the thread is woken, the mutex will
be locked again before the call to <code class="computeroutput"><span class="identifier">wait</span></code>
returns. This allows other threads to acquire the mutex in order to update
the shared data, and ensures that the data associated with the condition
is correctly synchronized.
</p>
<p>
In the mean time, another thread sets the condition to <code class="computeroutput"><span class="keyword">true</span></code>,
and then calls either <code class="computeroutput"><span class="identifier">notify_one</span></code>
or <code class="computeroutput"><span class="identifier">notify_all</span></code> on the condition
variable to wake one waiting thread or all the waiting threads respectively.
</p>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">retrieve_data</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">prepare_data</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">prepare_data_for_processing</span><span class="special">()</span>
<span class="special">{</span>
<span class="identifier">retrieve_data</span><span class="special">();</span>
<span class="identifier">prepare_data</span><span class="special">();</span>
<span class="special">{</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">lock_guard</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">></span> <span class="identifier">lock</span><span class="special">(</span><span class="identifier">mut</span><span class="special">);</span>
<span class="identifier">data_ready</span><span class="special">=</span><span class="keyword">true</span><span class="special">;</span>
<span class="special">}</span>
<span class="identifier">cond</span><span class="special">.</span><span class="identifier">notify_one</span><span class="special">();</span>
<span class="special">}</span>
</pre>
<p>
Note that the same mutex is locked before the shared data is updated, but
that the mutex does not have to be locked across the call to <code class="computeroutput"><span class="identifier">notify_one</span></code>.
</p>
<p>
This example uses an object of type <code class="computeroutput"><span class="identifier">condition_variable</span></code>,
but would work just as well with an object of type <code class="computeroutput"><span class="identifier">condition_variable_any</span></code>:
<code class="computeroutput"><span class="identifier">condition_variable_any</span></code> is
more general, and will work with any kind of lock or mutex, whereas <code class="computeroutput"><span class="identifier">condition_variable</span></code> requires that the lock
passed to <code class="computeroutput"><span class="identifier">wait</span></code> is an instance
of <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">></span></code>.
This enables <code class="computeroutput"><span class="identifier">condition_variable</span></code>
to make optimizations in some cases, based on the knowledge of the mutex
type; <code class="computeroutput"><span class="identifier">condition_variable_any</span></code>
typically has a more complex implementation than <code class="computeroutput"><span class="identifier">condition_variable</span></code>.
</p>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable" title="Class condition_variable">Class
<code class="computeroutput"><span class="identifier">condition_variable</span></code></a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.constructor"><code class="computeroutput"><span class="identifier">condition_variable</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.destructor"><code class="computeroutput"><span class="special">~</span><span class="identifier">condition_variable</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.notify_one"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_one</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.notify_all"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_all</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.wait"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.wait_predicate"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span> <span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span>
<span class="identifier">lock</span><span class="special">,</span>
<span class="identifier">predicate_type</span> <span class="identifier">pred</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.timed_wait"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.timed_wait_rel"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span>
<span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.timed_wait_predicate"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span>
<span class="identifier">lock</span><span class="special">,</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">,</span> <span class="identifier">predicate_type</span>
<span class="identifier">pred</span><span class="special">)</span></code></a></span></dt>
</dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">condition_variable</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">namespace</span> <span class="identifier">boost</span>
<span class="special">{</span>
<span class="keyword">class</span> <span class="identifier">condition_variable</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">condition_variable</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">condition_variable</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">notify_one</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">notify_all</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="comment">// backwards compatibility</span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">xtime</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">xtime</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="special">};</span>
<span class="special">}</span>
</pre>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.constructor"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.constructor" title="condition_variable()"><code class="computeroutput"><span class="identifier">condition_variable</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs an object of class <code class="computeroutput"><span class="identifier">condition_variable</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.destructor" title="~condition_variable()"><code class="computeroutput"><span class="special">~</span><span class="identifier">condition_variable</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
All threads waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> have been notified by a call
to <code class="computeroutput"><span class="identifier">notify_one</span></code> or
<code class="computeroutput"><span class="identifier">notify_all</span></code> (though
the respective calls to <code class="computeroutput"><span class="identifier">wait</span></code>
or <code class="computeroutput"><span class="identifier">timed_wait</span></code> need
not have returned).
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Destroys the object.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.notify_one"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.notify_one" title="void notify_one()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_one</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If any threads are currently <span class="emphasis"><em>blocked</em></span> waiting
on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
in a call to <code class="computeroutput"><span class="identifier">wait</span></code>
or <code class="computeroutput"><span class="identifier">timed_wait</span></code>,
unblocks one of those threads.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.notify_all"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.notify_all" title="void notify_all()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_all</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If any threads are currently <span class="emphasis"><em>blocked</em></span> waiting
on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
in a call to <code class="computeroutput"><span class="identifier">wait</span></code>
or <code class="computeroutput"><span class="identifier">timed_wait</span></code>,
unblocks all of those threads.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.wait"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.wait" title="void wait(boost::unique_lock<boost::mutex>& lock)"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread, and either no other thread is currently
waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
or the execution of the <code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code> member function on the <code class="computeroutput"><span class="identifier">lock</span></code> objects supplied in the
calls to <code class="computeroutput"><span class="identifier">wait</span></code> or
<code class="computeroutput"><span class="identifier">timed_wait</span></code> in all
the threads currently waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> would return the same value
as <code class="computeroutput"><span class="identifier">lock</span><span class="special">-></span><span class="identifier">mutex</span><span class="special">()</span></code>
for this call to <code class="computeroutput"><span class="identifier">wait</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically call <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">unlock</span><span class="special">()</span></code> and blocks the current thread.
The thread will unblock when notified by a call to <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_one</span><span class="special">()</span></code>
or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_all</span><span class="special">()</span></code>,
or spuriously. When the thread is unblocked (for whatever reason),
the lock is reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> before the call to <code class="computeroutput"><span class="identifier">wait</span></code> returns. The lock is also
reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> if the function exits with an
exception.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the wait
was interrupted by a call to <a class="link" href="thread_management.html#thread.thread_management.thread.interrupt" title="Member function interrupt()"><code class="computeroutput"><span class="identifier">interrupt</span><span class="special">()</span></code></a>
on the <a class="link" href="thread_management.html#thread.thread_management.thread" title="Class thread"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span></code></a> object associated
with the current thread of execution.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.wait_predicate"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.wait_predicate" title="template<typename predicate_type> void wait(boost::unique_lock<boost::mutex>& lock, predicate_type pred)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span> <span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span>
<span class="identifier">lock</span><span class="special">,</span>
<span class="identifier">predicate_type</span> <span class="identifier">pred</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd>
<p>
As-if
</p>
<pre class="programlisting"><span class="keyword">while</span><span class="special">(!</span><span class="identifier">pred</span><span class="special">())</span>
<span class="special">{</span>
<span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock</span><span class="special">);</span>
<span class="special">}</span>
</pre>
<p>
</p>
</dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.timed_wait"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.timed_wait" title="bool timed_wait(boost::unique_lock<boost::mutex>& lock,boost::system_time const& abs_time)"><code class="computeroutput"><span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread, and either no other thread is currently
waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
or the execution of the <code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code> member function on the <code class="computeroutput"><span class="identifier">lock</span></code> objects supplied in the
calls to <code class="computeroutput"><span class="identifier">wait</span></code> or
<code class="computeroutput"><span class="identifier">timed_wait</span></code> in all
the threads currently waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> would return the same value
as <code class="computeroutput"><span class="identifier">lock</span><span class="special">-></span><span class="identifier">mutex</span><span class="special">()</span></code>
for this call to <code class="computeroutput"><span class="identifier">wait</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically call <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">unlock</span><span class="special">()</span></code> and blocks the current thread.
The thread will unblock when notified by a call to <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_one</span><span class="special">()</span></code>
or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_all</span><span class="special">()</span></code>,
when the time as reported by <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">get_system_time</span><span class="special">()</span></code> would be equal to or later than
the specified <code class="computeroutput"><span class="identifier">abs_time</span></code>,
or spuriously. When the thread is unblocked (for whatever reason),
the lock is reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> before the call to <code class="computeroutput"><span class="identifier">wait</span></code> returns. The lock is also
reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> if the function exits with an
exception.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">false</span></code> if the call
is returning because the time specified by <code class="computeroutput"><span class="identifier">abs_time</span></code>
was reached, <code class="computeroutput"><span class="keyword">true</span></code>
otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the wait
was interrupted by a call to <a class="link" href="thread_management.html#thread.thread_management.thread.interrupt" title="Member function interrupt()"><code class="computeroutput"><span class="identifier">interrupt</span><span class="special">()</span></code></a>
on the <a class="link" href="thread_management.html#thread.thread_management.thread" title="Class thread"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span></code></a> object associated
with the current thread of execution.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.timed_wait_rel"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.timed_wait_rel" title="template<typename duration_type> bool timed_wait(boost::unique_lock<boost::mutex>& lock,duration_type const& rel_time)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span>
<span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread, and either no other thread is currently
waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
or the execution of the <code class="computeroutput"><span class="identifier">mutex</span><span class="special">()</span></code> member function on the <code class="computeroutput"><span class="identifier">lock</span></code> objects supplied in the
calls to <code class="computeroutput"><span class="identifier">wait</span></code> or
<code class="computeroutput"><span class="identifier">timed_wait</span></code> in all
the threads currently waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> would return the same value
as <code class="computeroutput"><span class="identifier">lock</span><span class="special">-></span><span class="identifier">mutex</span><span class="special">()</span></code>
for this call to <code class="computeroutput"><span class="identifier">wait</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically call <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">unlock</span><span class="special">()</span></code> and blocks the current thread.
The thread will unblock when notified by a call to <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_one</span><span class="special">()</span></code>
or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_all</span><span class="special">()</span></code>,
after the period of time indicated by the <code class="computeroutput"><span class="identifier">rel_time</span></code>
argument has elapsed, or spuriously. When the thread is unblocked
(for whatever reason), the lock is reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code>
before the call to <code class="computeroutput"><span class="identifier">wait</span></code>
returns. The lock is also reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code>
if the function exits with an exception.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">false</span></code> if the call
is returning because the time period specified by <code class="computeroutput"><span class="identifier">rel_time</span></code> has elapsed, <code class="computeroutput"><span class="keyword">true</span></code> otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the wait
was interrupted by a call to <a class="link" href="thread_management.html#thread.thread_management.thread.interrupt" title="Member function interrupt()"><code class="computeroutput"><span class="identifier">interrupt</span><span class="special">()</span></code></a>
on the <a class="link" href="thread_management.html#thread.thread_management.thread" title="Class thread"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span></code></a> object associated
with the current thread of execution.
</p></dd>
</dl>
</div>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>
The duration overload of timed_wait is difficult to use correctly.
The overload taking a predicate should be preferred in most cases.
</p></td></tr>
</table></div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable.timed_wait_predicate"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable.timed_wait_predicate" title="template<typename predicate_type> bool timed_wait(boost::unique_lock<boost::mutex>& lock, boost::system_time const& abs_time, predicate_type pred)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_lock</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mutex</span><span class="special">>&</span>
<span class="identifier">lock</span><span class="special">,</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">,</span> <span class="identifier">predicate_type</span>
<span class="identifier">pred</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd>
<p>
As-if
</p>
<pre class="programlisting"><span class="keyword">while</span><span class="special">(!</span><span class="identifier">pred</span><span class="special">())</span>
<span class="special">{</span>
<span class="keyword">if</span><span class="special">(!</span><span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock</span><span class="special">,</span><span class="identifier">abs_time</span><span class="special">))</span>
<span class="special">{</span>
<span class="keyword">return</span> <span class="identifier">pred</span><span class="special">();</span>
<span class="special">}</span>
<span class="special">}</span>
<span class="keyword">return</span> <span class="keyword">true</span><span class="special">;</span>
</pre>
<p>
</p>
</dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any" title="Class condition_variable_any">Class
<code class="computeroutput"><span class="identifier">condition_variable_any</span></code></a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.constructor"><code class="computeroutput"><span class="identifier">condition_variable_any</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.destructor"><code class="computeroutput"><span class="special">~</span><span class="identifier">condition_variable_any</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.notify_one"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_one</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.notify_all"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_all</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.wait"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">></span> <span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span>
<span class="identifier">lock</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.wait_predicate"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span> <span class="identifier">predicate_type</span>
<span class="identifier">pred</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.timed_wait"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span>
<span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.timed_wait_rel"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">rel_time</span><span class="special">)</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.timed_wait_predicate"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">,</span>
<span class="identifier">predicate_type</span> <span class="identifier">pred</span><span class="special">)</span></code></a></span></dt>
</dl></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">condition_variable</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">namespace</span> <span class="identifier">boost</span>
<span class="special">{</span>
<span class="keyword">class</span> <span class="identifier">condition_variable_any</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">condition_variable_any</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">condition_variable_any</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">notify_one</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">notify_all</span><span class="special">();</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="comment">// backwards compatibility</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">>&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">xtime</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">xtime</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">,</span><span class="identifier">predicate_type</span> <span class="identifier">predicate</span><span class="special">);</span>
<span class="special">};</span>
<span class="special">}</span>
</pre>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.constructor"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.constructor" title="condition_variable_any()"><code class="computeroutput"><span class="identifier">condition_variable_any</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs an object of class <code class="computeroutput"><span class="identifier">condition_variable_any</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.destructor" title="~condition_variable_any()"><code class="computeroutput"><span class="special">~</span><span class="identifier">condition_variable_any</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
All threads waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> have been notified by a call
to <code class="computeroutput"><span class="identifier">notify_one</span></code> or
<code class="computeroutput"><span class="identifier">notify_all</span></code> (though
the respective calls to <code class="computeroutput"><span class="identifier">wait</span></code>
or <code class="computeroutput"><span class="identifier">timed_wait</span></code> need
not have returned).
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Destroys the object.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.notify_one"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.notify_one" title="void notify_one()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_one</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If any threads are currently <span class="emphasis"><em>blocked</em></span> waiting
on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
in a call to <code class="computeroutput"><span class="identifier">wait</span></code>
or <code class="computeroutput"><span class="identifier">timed_wait</span></code>,
unblocks one of those threads.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.notify_all"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.notify_all" title="void notify_all()"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">notify_all</span><span class="special">()</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If any threads are currently <span class="emphasis"><em>blocked</em></span> waiting
on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
in a call to <code class="computeroutput"><span class="identifier">wait</span></code>
or <code class="computeroutput"><span class="identifier">timed_wait</span></code>,
unblocks all of those threads.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.wait"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.wait" title="template<typename lock_type> void wait(lock_type& lock)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">></span> <span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span>
<span class="identifier">lock</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically call <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">unlock</span><span class="special">()</span></code> and blocks the current thread.
The thread will unblock when notified by a call to <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_one</span><span class="special">()</span></code>
or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_all</span><span class="special">()</span></code>,
or spuriously. When the thread is unblocked (for whatever reason),
the lock is reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> before the call to <code class="computeroutput"><span class="identifier">wait</span></code> returns. The lock is also
reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> if the function exits with an
exception.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the wait
was interrupted by a call to <a class="link" href="thread_management.html#thread.thread_management.thread.interrupt" title="Member function interrupt()"><code class="computeroutput"><span class="identifier">interrupt</span><span class="special">()</span></code></a>
on the <a class="link" href="thread_management.html#thread.thread_management.thread" title="Class thread"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span></code></a> object associated
with the current thread of execution.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.wait_predicate"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.wait_predicate" title="template<typename lock_type,typename predicate_type> void wait(lock_type& lock, predicate_type pred)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span> <span class="identifier">predicate_type</span>
<span class="identifier">pred</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd>
<p>
As-if
</p>
<pre class="programlisting"><span class="keyword">while</span><span class="special">(!</span><span class="identifier">pred</span><span class="special">())</span>
<span class="special">{</span>
<span class="identifier">wait</span><span class="special">(</span><span class="identifier">lock</span><span class="special">);</span>
<span class="special">}</span>
</pre>
<p>
</p>
</dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.timed_wait"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.timed_wait" title="template<typename lock_type> bool timed_wait(lock_type& lock,boost::system_time const& abs_time)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">></span> <span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span>
<span class="identifier">lock</span><span class="special">,</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically call <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">unlock</span><span class="special">()</span></code> and blocks the current thread.
The thread will unblock when notified by a call to <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_one</span><span class="special">()</span></code>
or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_all</span><span class="special">()</span></code>,
when the time as reported by <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">get_system_time</span><span class="special">()</span></code> would be equal to or later than
the specified <code class="computeroutput"><span class="identifier">abs_time</span></code>,
or spuriously. When the thread is unblocked (for whatever reason),
the lock is reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> before the call to <code class="computeroutput"><span class="identifier">wait</span></code> returns. The lock is also
reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code> if the function exits with an
exception.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">false</span></code> if the call
is returning because the time specified by <code class="computeroutput"><span class="identifier">abs_time</span></code>
was reached, <code class="computeroutput"><span class="keyword">true</span></code>
otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the wait
was interrupted by a call to <a class="link" href="thread_management.html#thread.thread_management.thread.interrupt" title="Member function interrupt()"><code class="computeroutput"><span class="identifier">interrupt</span><span class="special">()</span></code></a>
on the <a class="link" href="thread_management.html#thread.thread_management.thread" title="Class thread"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span></code></a> object associated
with the current thread of execution.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.timed_wait_rel"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.timed_wait_rel" title="template<typename lock_type,typename duration_type> bool timed_wait(lock_type& lock,duration_type const& rel_time)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">duration_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span><span class="identifier">duration_type</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">rel_time</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Atomically call <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">unlock</span><span class="special">()</span></code> and blocks the current thread.
The thread will unblock when notified by a call to <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_one</span><span class="special">()</span></code>
or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">notify_all</span><span class="special">()</span></code>,
after the period of time indicated by the <code class="computeroutput"><span class="identifier">rel_time</span></code>
argument has elapsed, or spuriously. When the thread is unblocked
(for whatever reason), the lock is reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code>
before the call to <code class="computeroutput"><span class="identifier">wait</span></code>
returns. The lock is also reacquired by invoking <code class="computeroutput"><span class="identifier">lock</span><span class="special">.</span><span class="identifier">lock</span><span class="special">()</span></code>
if the function exits with an exception.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">false</span></code> if the call
is returning because the time period specified by <code class="computeroutput"><span class="identifier">rel_time</span></code> has elapsed, <code class="computeroutput"><span class="keyword">true</span></code> otherwise.
</p></dd>
<dt><span class="term">Postcondition:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">lock</span></code> is locked
by the current thread.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the wait
was interrupted by a call to <a class="link" href="thread_management.html#thread.thread_management.thread.interrupt" title="Member function interrupt()"><code class="computeroutput"><span class="identifier">interrupt</span><span class="special">()</span></code></a>
on the <a class="link" href="thread_management.html#thread.thread_management.thread" title="Class thread"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span></code></a> object associated
with the current thread of execution.
</p></dd>
</dl>
</div>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>
The duration overload of timed_wait is difficult to use correctly.
The overload taking a predicate should be preferred in most cases.
</p></td></tr>
</table></div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.condvar_ref.condition_variable_any.timed_wait_predicate"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition_variable_any.timed_wait_predicate" title="template<typename lock_type,typename predicate_type> bool timed_wait(lock_type& lock, boost::system_time const& abs_time, predicate_type pred)"><code class="computeroutput"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">lock_type</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">predicate_type</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock_type</span><span class="special">&</span> <span class="identifier">lock</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span>
<span class="keyword">const</span><span class="special">&</span>
<span class="identifier">abs_time</span><span class="special">,</span>
<span class="identifier">predicate_type</span> <span class="identifier">pred</span><span class="special">)</span></code></a>
</h5></div></div></div>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd>
<p>
As-if
</p>
<pre class="programlisting"><span class="keyword">while</span><span class="special">(!</span><span class="identifier">pred</span><span class="special">())</span>
<span class="special">{</span>
<span class="keyword">if</span><span class="special">(!</span><span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">lock</span><span class="special">,</span><span class="identifier">abs_time</span><span class="special">))</span>
<span class="special">{</span>
<span class="keyword">return</span> <span class="identifier">pred</span><span class="special">();</span>
<span class="special">}</span>
<span class="special">}</span>
<span class="keyword">return</span> <span class="keyword">true</span><span class="special">;</span>
</pre>
<p>
</p>
</dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.condvar_ref.condition"></a><a class="link" href="synchronization.html#thread.synchronization.condvar_ref.condition" title="Typedef condition">Typedef
<code class="computeroutput"><span class="identifier">condition</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">condition</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">typedef</span> <span class="identifier">condition_variable_any</span> <span class="identifier">condition</span><span class="special">;</span>
</pre>
<p>
The typedef <code class="computeroutput"><span class="identifier">condition</span></code> is
provided for backwards compatibility with previous boost releases.
</p>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.once"></a><a class="link" href="synchronization.html#thread.synchronization.once" title="One-time Initialization">One-time Initialization</a>
</h3></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.once.once_flag">Typedef <code class="computeroutput"><span class="identifier">once_flag</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.once.call_once">Non-member function
<code class="computeroutput"><span class="identifier">call_once</span></code></a></span></dt>
</dl></div>
<p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">call_once</span></code> provides a mechanism for ensuring
that an initialization routine is run exactly once without data races or
deadlocks.
</p>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.once.once_flag"></a><a class="link" href="synchronization.html#thread.synchronization.once.once_flag" title="Typedef once_flag">Typedef <code class="computeroutput"><span class="identifier">once_flag</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">once</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">typedef</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">type</span> <span class="identifier">once_flag</span><span class="special">;</span>
<span class="preprocessor">#define</span> <span class="identifier">BOOST_ONCE_INIT</span> <span class="identifier">platform</span><span class="special">-</span><span class="identifier">specific</span><span class="special">-</span><span class="identifier">initializer</span>
</pre>
<p>
Objects of type <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">once_flag</span></code> shall be initialized with
<code class="computeroutput"><span class="identifier">BOOST_ONCE_INIT</span></code>:
</p>
<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">once_flag</span> <span class="identifier">f</span><span class="special">=</span><span class="identifier">BOOST_ONCE_INIT</span><span class="special">;</span>
</pre>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.once.call_once"></a><a class="link" href="synchronization.html#thread.synchronization.once.call_once" title="Non-member function call_once">Non-member function
<code class="computeroutput"><span class="identifier">call_once</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">once</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Callable</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">call_once</span><span class="special">(</span><span class="identifier">once_flag</span><span class="special">&</span> <span class="identifier">flag</span><span class="special">,</span><span class="identifier">Callable</span> <span class="identifier">func</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Requires:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">Callable</span></code> is <code class="computeroutput"><span class="identifier">CopyConstructible</span></code>. Copying <code class="computeroutput"><span class="identifier">func</span></code> shall have no side effects,
and the effect of calling the copy shall be equivalent to calling
the original.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Calls to <code class="computeroutput"><span class="identifier">call_once</span></code>
on the same <code class="computeroutput"><span class="identifier">once_flag</span></code>
object are serialized. If there has been no prior effective <code class="computeroutput"><span class="identifier">call_once</span></code> on the same <code class="computeroutput"><span class="identifier">once_flag</span></code> object, the argument
<code class="computeroutput"><span class="identifier">func</span></code> (or a copy thereof)
is called as-if by invoking <code class="computeroutput"><span class="identifier">func</span><span class="special">()</span></code>, and the invocation of <code class="computeroutput"><span class="identifier">call_once</span></code> is effective if and only
if <code class="computeroutput"><span class="identifier">func</span><span class="special">()</span></code>
returns without exception. If an exception is thrown, the exception
is propagated to the caller. If there has been a prior effective
<code class="computeroutput"><span class="identifier">call_once</span></code> on the
same <code class="computeroutput"><span class="identifier">once_flag</span></code> object,
the <code class="computeroutput"><span class="identifier">call_once</span></code> returns
without invoking <code class="computeroutput"><span class="identifier">func</span></code>.
</p></dd>
<dt><span class="term">Synchronization:</span></dt>
<dd><p>
The completion of an effective <code class="computeroutput"><span class="identifier">call_once</span></code>
invocation on a <code class="computeroutput"><span class="identifier">once_flag</span></code>
object, synchronizes with all subsequent <code class="computeroutput"><span class="identifier">call_once</span></code>
invocations on the same <code class="computeroutput"><span class="identifier">once_flag</span></code>
object.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">thread_resource_error</span></code>
when the effects cannot be achieved. or any exception propagated
from <code class="computeroutput"><span class="identifier">func</span></code>.
</p></dd>
<dt><span class="term">Note:</span></dt>
<dd><p>
The function passed to <code class="computeroutput"><span class="identifier">call_once</span></code>
must not also call <code class="computeroutput"><span class="identifier">call_once</span></code>
passing the same <code class="computeroutput"><span class="identifier">once_flag</span></code>
object. This may cause deadlock, or invoking the passed function
a second time. The alternative is to allow the second call to return
immediately, but that assumes the code knows it has been called recursively,
and can proceed even though the call to <code class="computeroutput"><span class="identifier">call_once</span></code>
didn't actually call the function, in which case it could also avoid
calling <code class="computeroutput"><span class="identifier">call_once</span></code>
recursively.
</p></dd>
</dl>
</div>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">call_once</span><span class="special">(</span><span class="keyword">void</span> <span class="special">(*</span><span class="identifier">func</span><span class="special">)(),</span><span class="identifier">once_flag</span><span class="special">&</span> <span class="identifier">flag</span><span class="special">);</span>
</pre>
<p>
This second overload is provided for backwards compatibility. The effects
of <code class="computeroutput"><span class="identifier">call_once</span><span class="special">(</span><span class="identifier">func</span><span class="special">,</span><span class="identifier">flag</span><span class="special">)</span></code>
shall be the same as those of <code class="computeroutput"><span class="identifier">call_once</span><span class="special">(</span><span class="identifier">flag</span><span class="special">,</span><span class="identifier">func</span><span class="special">)</span></code>.
</p>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.barriers"></a><a class="link" href="synchronization.html#thread.synchronization.barriers" title="Barriers">Barriers</a>
</h3></div></div></div>
<div class="toc"><dl><dt><span class="section"><a href="synchronization.html#thread.synchronization.barriers.barrier">Class <code class="computeroutput"><span class="identifier">barrier</span></code></a></span></dt></dl></div>
<p>
A barrier is a simple concept. Also known as a <span class="emphasis"><em>rendezvous</em></span>,
it is a synchronization point between multiple threads. The barrier is configured
for a particular number of threads (<code class="computeroutput"><span class="identifier">n</span></code>),
and as threads reach the barrier they must wait until all <code class="computeroutput"><span class="identifier">n</span></code>
threads have arrived. Once the <code class="computeroutput"><span class="identifier">n</span></code>-th
thread has reached the barrier, all the waiting threads can proceed, and
the barrier is reset.
</p>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.barriers.barrier"></a><a class="link" href="synchronization.html#thread.synchronization.barriers.barrier" title="Class barrier">Class <code class="computeroutput"><span class="identifier">barrier</span></code></a>
</h4></div></div></div>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">barrier</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">barrier</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="identifier">barrier</span><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">count</span><span class="special">);</span>
<span class="special">~</span><span class="identifier">barrier</span><span class="special">();</span>
<span class="keyword">bool</span> <span class="identifier">wait</span><span class="special">();</span>
<span class="special">};</span>
</pre>
<p>
Instances of <a class="link" href="synchronization.html#thread.synchronization.barriers.barrier" title="Class barrier"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">barrier</span></code></a> are not copyable or movable.
</p>
<h6>
<a name="thread.synchronization.barriers.barrier.h0"></a>
<span><a name="thread.synchronization.barriers.barrier.constructor"></a></span><a class="link" href="synchronization.html#thread.synchronization.barriers.barrier.constructor">Constructor</a>
</h6>
<pre class="programlisting"><span class="identifier">barrier</span><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">count</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Construct a barrier for <code class="computeroutput"><span class="identifier">count</span></code>
threads.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
<h6>
<a name="thread.synchronization.barriers.barrier.h1"></a>
<span><a name="thread.synchronization.barriers.barrier.destructor"></a></span><a class="link" href="synchronization.html#thread.synchronization.barriers.barrier.destructor">Destructor</a>
</h6>
<pre class="programlisting"><span class="special">~</span><span class="identifier">barrier</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Precondition:</span></dt>
<dd><p>
No threads are waiting on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Destroys <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
<h6>
<a name="thread.synchronization.barriers.barrier.h2"></a>
<span><a name="thread.synchronization.barriers.barrier.member_function__code__phrase_role__identifier__wait__phrase___code_"></a></span><a class="link" href="synchronization.html#thread.synchronization.barriers.barrier.member_function__code__phrase_role__identifier__wait__phrase___code_">Member
function <code class="computeroutput"><span class="identifier">wait</span></code></a>
</h6>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">wait</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Block until <code class="computeroutput"><span class="identifier">count</span></code>
threads have called <code class="computeroutput"><span class="identifier">wait</span></code>
on <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
When the <code class="computeroutput"><span class="identifier">count</span></code>-th
thread calls <code class="computeroutput"><span class="identifier">wait</span></code>,
all waiting threads are unblocked, and the barrier is reset.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> for exactly one
thread from each batch of waiting threads, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_resource_error</span></code> if an error
occurs.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="thread.synchronization.futures"></a><a class="link" href="synchronization.html#thread.synchronization.futures" title="Futures">Futures</a>
</h3></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.overview">Overview</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.creating">Creating asynchronous
values</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.lazy_futures">Wait Callbacks
and Lazy Futures</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference">Futures Reference</a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.futures.overview"></a><a class="link" href="synchronization.html#thread.synchronization.futures.overview" title="Overview">Overview</a>
</h4></div></div></div>
<p>
The futures library provides a means of handling synchronous future values,
whether those values are generated by another thread, or on a single thread
in response to external stimuli, or on-demand.
</p>
<p>
This is done through the provision of four class templates: <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a> which are used to
retrieve the asynchronous results, and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a> which are used to
generate the asynchronous results.
</p>
<p>
An instance of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> holds the one and
only reference to a result. Ownership can be transferred between instances
using the move constructor or move-assignment operator, but at most one
instance holds a reference to a given asynchronous result. When the result
is ready, it is returned from <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get" title="Member function get()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">get</span><span class="special">()</span></code></a>
by rvalue-reference to allow the result to be moved or copied as appropriate
for the type.
</p>
<p>
On the other hand, many instances of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a> may reference the
same result. Instances can be freely copied and assigned, and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get" title="Member function get()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">get</span><span class="special">()</span></code></a>
returns a <code class="computeroutput"><span class="keyword">const</span></code> reference
so that multiple calls to <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get" title="Member function get()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">get</span><span class="special">()</span></code></a>
are safe. You can move an instance of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> into an instance
of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a>, thus transferring
ownership of the associated asynchronous result, but not vice-versa.
</p>
<p>
You can wait for futures either individually or with one of the <a class="link" href="synchronization.html#thread.synchronization.futures.reference.wait_for_any" title="Non-member function wait_for_any()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">wait_for_any</span><span class="special">()</span></code></a>
and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.wait_for_all" title="Non-member function wait_for_all()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">wait_for_all</span><span class="special">()</span></code></a>
functions.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.futures.creating"></a><a class="link" href="synchronization.html#thread.synchronization.futures.creating" title="Creating asynchronous values">Creating asynchronous
values</a>
</h4></div></div></div>
<p>
You can set the value in a future with either a <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> or a <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a>. A <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a> is a callable object
that wraps a function or callable object. When the packaged task is invoked,
it invokes the contained function in turn, and populates a future with
the return value. This is an answer to the perennial question: "how
do I return a value from a thread?": package the function you wish
to run as a <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a> and pass the packaged
task to the thread constructor. The future retrieved from the packaged
task can then be used to obtain the return value. If the function throws
an exception, that is stored in the future in place of the return value.
</p>
<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">calculate_the_answer_to_life_the_universe_and_everything</span><span class="special">()</span>
<span class="special">{</span>
<span class="keyword">return</span> <span class="number">42</span><span class="special">;</span>
<span class="special">}</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">pt</span><span class="special">(</span><span class="identifier">calculate_the_answer_to_life_the_universe_and_everything</span><span class="special">);</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">fi</span><span class="special">=</span><span class="identifier">pt</span><span class="special">.</span><span class="identifier">get_future</span><span class="special">();</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span> <span class="identifier">task</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">move</span><span class="special">(</span><span class="identifier">pt</span><span class="special">));</span> <span class="comment">// launch task on a thread</span>
<span class="identifier">fi</span><span class="special">.</span><span class="identifier">wait</span><span class="special">();</span> <span class="comment">// wait for it to finish</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">is_ready</span><span class="special">());</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">has_value</span><span class="special">());</span>
<span class="identifier">assert</span><span class="special">(!</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">has_exception</span><span class="special">());</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">get_state</span><span class="special">()==</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span><span class="special">);</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">get</span><span class="special">()==</span><span class="number">42</span><span class="special">);</span>
</pre>
<p>
A <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> is a bit more low level:
it just provides explicit functions to store a value or an exception in
the associated future. A promise can therefore be used where the value
may come from more than one possible source, or where a single operation
may produce multiple values.
</p>
<pre class="programlisting"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">pi</span><span class="special">;</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">fi</span><span class="special">;</span>
<span class="identifier">fi</span><span class="special">=</span><span class="identifier">pi</span><span class="special">.</span><span class="identifier">get_future</span><span class="special">();</span>
<span class="identifier">pi</span><span class="special">.</span><span class="identifier">set_value</span><span class="special">(</span><span class="number">42</span><span class="special">);</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">is_ready</span><span class="special">());</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">has_value</span><span class="special">());</span>
<span class="identifier">assert</span><span class="special">(!</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">has_exception</span><span class="special">());</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">get_state</span><span class="special">()==</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span><span class="special">);</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">fi</span><span class="special">.</span><span class="identifier">get</span><span class="special">()==</span><span class="number">42</span><span class="special">);</span>
</pre>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.futures.lazy_futures"></a><a class="link" href="synchronization.html#thread.synchronization.futures.lazy_futures" title="Wait Callbacks and Lazy Futures">Wait Callbacks
and Lazy Futures</a>
</h4></div></div></div>
<p>
Both <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a> support <span class="emphasis"><em>wait
callbacks</em></span> that are invoked when a thread blocks in a call to
<code class="computeroutput"><span class="identifier">wait</span><span class="special">()</span></code>
or <code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code>
on a future that is waiting for the result from the <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a>, in the thread that
is doing the waiting. These can be set using the <code class="computeroutput"><span class="identifier">set_wait_callback</span><span class="special">()</span></code> member function on the <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a> in question.
</p>
<p>
This allows <span class="emphasis"><em>lazy futures</em></span> where the result is not actually
computed until it is needed by some thread. In the example below, the call
to <code class="computeroutput"><span class="identifier">f</span><span class="special">.</span><span class="identifier">get</span><span class="special">()</span></code>
invokes the callback <code class="computeroutput"><span class="identifier">invoke_lazy_task</span></code>,
which runs the task to set the value. If you remove the call to <code class="computeroutput"><span class="identifier">f</span><span class="special">.</span><span class="identifier">get</span><span class="special">()</span></code>, the task is not ever run.
</p>
<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">calculate_the_answer_to_life_the_universe_and_everything</span><span class="special">()</span>
<span class="special">{</span>
<span class="keyword">return</span> <span class="number">42</span><span class="special">;</span>
<span class="special">}</span>
<span class="keyword">void</span> <span class="identifier">invoke_lazy_task</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span><span class="special"><</span><span class="keyword">int</span><span class="special">>&</span> <span class="identifier">task</span><span class="special">)</span>
<span class="special">{</span>
<span class="keyword">try</span>
<span class="special">{</span>
<span class="identifier">task</span><span class="special">();</span>
<span class="special">}</span>
<span class="keyword">catch</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">task_already_started</span><span class="special">&)</span>
<span class="special">{}</span>
<span class="special">}</span>
<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
<span class="special">{</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">task</span><span class="special">(</span><span class="identifier">calculate_the_answer_to_life_the_universe_and_everything</span><span class="special">);</span>
<span class="identifier">task</span><span class="special">.</span><span class="identifier">set_wait_callback</span><span class="special">(</span><span class="identifier">invoke_lazy_task</span><span class="special">);</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">f</span><span class="special">(</span><span class="identifier">task</span><span class="special">.</span><span class="identifier">get_future</span><span class="special">());</span>
<span class="identifier">assert</span><span class="special">(</span><span class="identifier">f</span><span class="special">.</span><span class="identifier">get</span><span class="special">()==</span><span class="number">42</span><span class="special">);</span>
<span class="special">}</span>
</pre>
</div>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="thread.synchronization.futures.reference"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference" title="Futures Reference">Futures Reference</a>
</h4></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference.future_state"><code class="computeroutput"><span class="identifier">state</span></code> enum</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference.unique_future"><code class="computeroutput"><span class="identifier">unique_future</span></code> class template</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference.shared_future"><code class="computeroutput"><span class="identifier">shared_future</span></code> class template</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference.promise"><code class="computeroutput"><span class="identifier">promise</span></code> class template</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference.packaged_task"><code class="computeroutput"><span class="identifier">packaged_task</span></code> class template</a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference.wait_for_any">Non-member
function <code class="computeroutput"><span class="identifier">wait_for_any</span><span class="special">()</span></code></a></span></dt>
<dt><span class="section"><a href="synchronization.html#thread.synchronization.futures.reference.wait_for_all">Non-member
function <code class="computeroutput"><span class="identifier">wait_for_all</span><span class="special">()</span></code></a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.futures.reference.future_state"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">state</span></code> enum</a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">future_state</span>
<span class="special">{</span>
<span class="keyword">enum</span> <span class="identifier">state</span> <span class="special">{</span><span class="identifier">uninitialized</span><span class="special">,</span> <span class="identifier">waiting</span><span class="special">,</span> <span class="identifier">ready</span><span class="special">};</span>
<span class="special">}</span>
</pre>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.futures.reference.unique_future"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">unique_future</span></code> class template</a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">R</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">unique_future</span>
<span class="special">{</span>
<span class="identifier">unique_future</span><span class="special">(</span><span class="identifier">unique_future</span> <span class="special">&</span> <span class="identifier">rhs</span><span class="special">);//</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span>
<span class="identifier">unique_future</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">unique_future</span><span class="special">&</span> <span class="identifier">rhs</span><span class="special">);//</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="keyword">typedef</span> <span class="identifier">future_state</span><span class="special">::</span><span class="identifier">state</span> <span class="identifier">state</span><span class="special">;</span>
<span class="identifier">unique_future</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">unique_future</span><span class="special">();</span>
<span class="comment">// move support</span>
<span class="identifier">unique_future</span><span class="special">(</span><span class="identifier">unique_future</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">unique_future</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">unique_future</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">unique_future</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="comment">// retrieving the value</span>
<span class="identifier">R</span><span class="special">&&</span> <span class="identifier">get</span><span class="special">();</span>
<span class="comment">// functions to check state</span>
<span class="identifier">state</span> <span class="identifier">get_state</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">is_ready</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">has_exception</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">has_value</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="comment">// waiting for the result to be ready</span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Duration</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">Duration</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">timed_wait_until</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.default_constructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.default_constructor" title="Default Constructor">Default
Constructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">unique_future</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs an uninitialized future.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span></code></a> returns <code class="computeroutput"><span class="keyword">false</span></code>. <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">uninitialized</span></code></a>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.destructor" title="Destructor">Destructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="special">~</span><span class="identifier">unique_future</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Destroys <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.move_constructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.move_constructor" title="Move Constructor">Move
Constructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">unique_future</span><span class="special">(</span><span class="identifier">unique_future</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs a new future, and transfers ownership of the asynchronous
result associated with <code class="computeroutput"><span class="identifier">other</span></code>
to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns the value of <code class="computeroutput"><span class="identifier">other</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code> prior to the call. <code class="computeroutput"><span class="identifier">other</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">uninitialized</span></code></a>. If <code class="computeroutput"><span class="identifier">other</span></code> was associated with an
asynchronous result, that result is now associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
<code class="computeroutput"><span class="identifier">other</span></code> is not
associated with any asynchronous result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
If the compiler does not support rvalue-references, this is implemented
using the boost.thread move emulation.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.move_assignment"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.move_assignment" title="Move Assignment Operator">Move
Assignment Operator</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">unique_future</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">unique_future</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Transfers ownership of the asynchronous result associated with
<code class="computeroutput"><span class="identifier">other</span></code> to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns the value of <code class="computeroutput"><span class="identifier">other</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code> prior to the call. <code class="computeroutput"><span class="identifier">other</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">uninitialized</span></code></a>. If <code class="computeroutput"><span class="identifier">other</span></code> was associated with an
asynchronous result, that result is now associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
<code class="computeroutput"><span class="identifier">other</span></code> is not
associated with any asynchronous result. If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> was associated with an asynchronous
result prior to the call, that result no longer has an associated
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> instance.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
If the compiler does not support rvalue-references, this is implemented
using the boost.thread move emulation.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.swap"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.swap" title="Member function swap()">Member
function <code class="computeroutput"><span class="identifier">swap</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">unique_future</span> <span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Swaps ownership of the asynchronous results associated with
<code class="computeroutput"><span class="identifier">other</span></code> and <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns the value of <code class="computeroutput"><span class="identifier">other</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code> prior to the call. <code class="computeroutput"><span class="identifier">other</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code>
returns the value of <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code> prior to the call. If <code class="computeroutput"><span class="identifier">other</span></code> was associated with an
asynchronous result, that result is now associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
otherwise <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
has no associated result. If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> was associated with an asynchronous
result, that result is now associated with <code class="computeroutput"><span class="identifier">other</span></code>,
otherwise <code class="computeroutput"><span class="identifier">other</span></code>
has no associated result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.get"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get" title="Member function get()">Member
function <code class="computeroutput"><span class="identifier">get</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">R</span><span class="special">&&</span> <span class="identifier">get</span><span class="special">();</span>
<span class="identifier">R</span><span class="special">&</span> <span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">&>::</span><span class="identifier">get</span><span class="special">();</span>
<span class="keyword">void</span> <span class="identifier">unique_future</span><span class="special"><</span><span class="keyword">void</span><span class="special">>::</span><span class="identifier">get</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready as-if by a call to <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.wait" title="Member function wait()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">wait</span><span class="special">()</span></code></a>,
and retrieves the result (whether that is a value or an exception).
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
If the result type <code class="computeroutput"><span class="identifier">R</span></code>
is a reference, returns the stored reference. If <code class="computeroutput"><span class="identifier">R</span></code> is <code class="computeroutput"><span class="keyword">void</span></code>,
there is no return value. Otherwise, returns an rvalue-reference
to the value stored in the asynchronous result.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted. Any exception
stored in the asynchronous result in place of a value.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">get</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.wait"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.wait" title="Member function wait()">Member
function <code class="computeroutput"><span class="identifier">wait</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">wait</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready. If the result is not ready on entry, and the result
has a <span class="emphasis"><em>wait callback</em></span> set, that callback is
invoked prior to waiting.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted. Any exception
thrown by the <span class="emphasis"><em>wait callback</em></span> if such a callback
is called.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a>.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">wait</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.timed_wait_duration"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.timed_wait_duration" title="Member function timed_wait()">Member
function <code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Duration</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">Duration</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">wait_duration</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready, or the time specified by <code class="computeroutput"><span class="identifier">wait_duration</span></code>
has elapsed. If the result is not ready on entry, and the result
has a <span class="emphasis"><em>wait callback</em></span> set, that callback is
invoked prior to waiting.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, and that result is
ready before the specified time has elapsed, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted. Any exception
thrown by the <span class="emphasis"><em>wait callback</em></span> if such a callback
is called.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
If this call returned <code class="computeroutput"><span class="keyword">true</span></code>,
then <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code> and
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a>.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>. <code class="computeroutput"><span class="identifier">Duration</span></code> must be a type that
meets the Boost.DateTime time duration requirements.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.timed_wait_absolute"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.timed_wait_absolute" title="Member function timed_wait()">Member
function <code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">wait_timeout</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready, or the time point specified by <code class="computeroutput"><span class="identifier">wait_timeout</span></code>
has passed. If the result is not ready on entry, and the result
has a <span class="emphasis"><em>wait callback</em></span> set, that callback is
invoked prior to waiting.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, and that result is
ready before the specified time has passed, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted. Any exception
thrown by the <span class="emphasis"><em>wait callback</em></span> if such a callback
is called.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
If this call returned <code class="computeroutput"><span class="keyword">true</span></code>,
then <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code> and
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a>.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.is_ready"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.is_ready" title="Member function is_ready()">Member
function <code class="computeroutput"><span class="identifier">is_ready</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">is_ready</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Checks to see if the asynchronous result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is set.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, and that result is
ready for retrieval, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.has_value"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.has_value" title="Member function has_value()">Member
function <code class="computeroutput"><span class="identifier">has_value</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">has_value</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Checks to see if the asynchronous result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is set with a value rather than an exception.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, that result is ready
for retrieval, and the result is a stored value, <code class="computeroutput"><span class="keyword">false</span></code> otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.has_exception"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.has_exception" title="Member function has_exception()">Member
function <code class="computeroutput"><span class="identifier">has_exception</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">has_exception</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Checks to see if the asynchronous result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is set with an exception rather than a value.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, that result is ready
for retrieval, and the result is a stored exception, <code class="computeroutput"><span class="keyword">false</span></code> otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.unique_future.get_state"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.get_state" title="Member function get_state()">Member
function <code class="computeroutput"><span class="identifier">get_state</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">state</span> <span class="identifier">get_state</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Determine the state of the asynchronous result associated with
<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
if any.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">uninitialized</span></code></a> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a> if the asynchronous
result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is ready for retrieval,
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">waiting</span></code></a> otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.futures.reference.shared_future"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">shared_future</span></code> class template</a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">R</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">shared_future</span>
<span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="keyword">typedef</span> <span class="identifier">future_state</span><span class="special">::</span><span class="identifier">state</span> <span class="identifier">state</span><span class="special">;</span>
<span class="identifier">shared_future</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">shared_future</span><span class="special">();</span>
<span class="comment">// copy support</span>
<span class="identifier">shared_future</span><span class="special">(</span><span class="identifier">shared_future</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_future</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">shared_future</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="comment">// move support</span>
<span class="identifier">shared_future</span><span class="special">(</span><span class="identifier">shared_future</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_future</span><span class="special">(</span><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_future</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">shared_future</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">shared_future</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">shared_future</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="comment">// retrieving the value</span>
<span class="identifier">R</span> <span class="identifier">get</span><span class="special">();</span>
<span class="comment">// functions to check state, and wait for ready</span>
<span class="identifier">state</span> <span class="identifier">get_state</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">is_ready</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">has_exception</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">has_value</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="comment">// waiting for the result to be ready</span>
<span class="keyword">void</span> <span class="identifier">wait</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Duration</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">Duration</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">rel_time</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <span class="identifier">timed_wait_until</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">abs_time</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.default_constructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.default_constructor" title="Default Constructor">Default
Constructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">shared_future</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs an uninitialized future.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span></code></a> returns <code class="computeroutput"><span class="keyword">false</span></code>. <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">uninitialized</span></code></a>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.get"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get" title="Member function get()">Member
function <code class="computeroutput"><span class="identifier">get</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">const</span> <span class="identifier">R</span><span class="special">&</span> <span class="identifier">get</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready as-if by a call to <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.wait" title="Member function wait()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">wait</span><span class="special">()</span></code></a>,
and returns a <code class="computeroutput"><span class="keyword">const</span></code>
reference to the result.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
If the result type <code class="computeroutput"><span class="identifier">R</span></code>
is a reference, returns the stored reference. If <code class="computeroutput"><span class="identifier">R</span></code> is <code class="computeroutput"><span class="keyword">void</span></code>,
there is no return value. Otherwise, returns a <code class="computeroutput"><span class="keyword">const</span></code> reference to the value stored
in the asynchronous result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">get</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.wait"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.wait" title="Member function wait()">Member
function <code class="computeroutput"><span class="identifier">wait</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">wait</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready. If the result is not ready on entry, and the result
has a <span class="emphasis"><em>wait callback</em></span> set, that callback is
invoked prior to waiting.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted. Any exception
thrown by the <span class="emphasis"><em>wait callback</em></span> if such a callback
is called.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code>. <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a>.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">wait</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.timed_wait_duration"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.timed_wait_duration" title="Member function timed_wait()">Member
function <code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Duration</span><span class="special">></span>
<span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">Duration</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">wait_duration</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready, or the time specified by <code class="computeroutput"><span class="identifier">wait_duration</span></code>
has elapsed. If the result is not ready on entry, and the result
has a <span class="emphasis"><em>wait callback</em></span> set, that callback is
invoked prior to waiting.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, and that result is
ready before the specified time has elapsed, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted. Any exception
thrown by the <span class="emphasis"><em>wait callback</em></span> if such a callback
is called.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
If this call returned <code class="computeroutput"><span class="keyword">true</span></code>,
then <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code> and
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a>.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>. <code class="computeroutput"><span class="identifier">Duration</span></code> must be a type that
meets the Boost.DateTime time duration requirements.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.timed_wait_absolute"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.timed_wait_absolute" title="Member function timed_wait()">Member
function <code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">timed_wait</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system_time</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">wait_timeout</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, waits until the result
is ready, or the time point specified by <code class="computeroutput"><span class="identifier">wait_timeout</span></code>
has passed. If the result is not ready on entry, and the result
has a <span class="emphasis"><em>wait callback</em></span> set, that callback is
invoked prior to waiting.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, and that result is
ready before the specified time has passed, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_uninitialized</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is not ready at the point
of the call, and the current thread is interrupted. Any exception
thrown by the <span class="emphasis"><em>wait callback</em></span> if such a callback
is called.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
If this call returned <code class="computeroutput"><span class="keyword">true</span></code>,
then <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.is_ready" title="Member function is_ready()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">is_ready</span><span class="special">()</span></code></a>
returns <code class="computeroutput"><span class="keyword">true</span></code> and
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get_state" title="Member function get_state()"><code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">get_state</span><span class="special">()</span></code></a>
returns <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a>.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">timed_wait</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.is_ready"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.is_ready" title="Member function is_ready()">Member
function <code class="computeroutput"><span class="identifier">is_ready</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">is_ready</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Checks to see if the asynchronous result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is set.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, and that result is
ready for retrieval, <code class="computeroutput"><span class="keyword">false</span></code>
otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.has_value"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.has_value" title="Member function has_value()">Member
function <code class="computeroutput"><span class="identifier">has_value</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">has_value</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Checks to see if the asynchronous result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is set with a value rather than an exception.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, that result is ready
for retrieval, and the result is a stored value, <code class="computeroutput"><span class="keyword">false</span></code> otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.has_exception"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.has_exception" title="Member function has_exception()">Member
function <code class="computeroutput"><span class="identifier">has_exception</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">has_exception</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Checks to see if the asynchronous result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is set with an exception rather than a value.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<code class="computeroutput"><span class="keyword">true</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is associated with an asynchronous result, that result is ready
for retrieval, and the result is a stored exception, <code class="computeroutput"><span class="keyword">false</span></code> otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.shared_future.get_state"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.get_state" title="Member function get_state()">Member
function <code class="computeroutput"><span class="identifier">get_state</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">state</span> <span class="identifier">get_state</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Determine the state of the asynchronous result associated with
<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
if any.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">uninitialized</span></code></a> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
is not associated with an asynchronous result. <a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">ready</span></code></a> if the asynchronous
result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is ready for retrieval,
<a class="link" href="synchronization.html#thread.synchronization.futures.reference.future_state" title="state enum"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_state</span><span class="special">::</span><span class="identifier">waiting</span></code></a> otherwise.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.futures.reference.promise"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">promise</span></code> class template</a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">R</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">promise</span>
<span class="special">{</span>
<span class="identifier">promise</span><span class="special">(</span><span class="identifier">promise</span> <span class="special">&</span> <span class="identifier">rhs</span><span class="special">);//</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span>
<span class="identifier">promise</span> <span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">promise</span> <span class="special">&</span> <span class="identifier">rhs</span><span class="special">);//</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="comment">// template <class Allocator> explicit promise(Allocator a);</span>
<span class="identifier">promise</span><span class="special">();</span>
<span class="special">~</span><span class="identifier">promise</span><span class="special">();</span>
<span class="comment">// Move support</span>
<span class="identifier">promise</span><span class="special">(</span><span class="identifier">promise</span> <span class="special">&&</span> <span class="identifier">rhs</span><span class="special">);</span>
<span class="identifier">promise</span> <span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">promise</span><span class="special">&&</span> <span class="identifier">rhs</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">promise</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="comment">// Result retrieval</span>
<span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="identifier">get_future</span><span class="special">();</span>
<span class="comment">// Set the value</span>
<span class="keyword">void</span> <span class="identifier">set_value</span><span class="special">(</span><span class="identifier">R</span><span class="special">&</span> <span class="identifier">r</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">set_value</span><span class="special">(</span><span class="identifier">R</span><span class="special">&&</span> <span class="identifier">r</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">set_exception</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">exception_ptr</span> <span class="identifier">e</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">set_wait_callback</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">);</span>
<span class="special">};</span>
</pre>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.default_constructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.default_constructor" title="Default Constructor">Default
Constructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">promise</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs a new <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> with no associated
result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.move_constructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.move_constructor" title="Move Constructor">Move
Constructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">promise</span><span class="special">(</span><span class="identifier">promise</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs a new <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a>, and transfers
ownership of the result associated with <code class="computeroutput"><span class="identifier">other</span></code>
to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
leaving <code class="computeroutput"><span class="identifier">other</span></code>
with no associated result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
If the compiler does not support rvalue-references, this is implemented
using the boost.thread move emulation.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.move_assignment"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.move_assignment" title="Move Assignment Operator">Move
Assignment Operator</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">promise</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">promise</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Transfers ownership of the result associated with <code class="computeroutput"><span class="identifier">other</span></code> to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>, leaving <code class="computeroutput"><span class="identifier">other</span></code>
with no associated result. If there was already a result associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
and that result was not <span class="emphasis"><em>ready</em></span>, sets any
futures associated with that result to <span class="emphasis"><em>ready</em></span>
with a <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">broken_promise</span></code>
exception as the result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
If the compiler does not support rvalue-references, this is implemented
using the boost.thread move emulation.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.destructor" title="Destructor">Destructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="special">~</span><span class="identifier">promise</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Destroys <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
If there was a result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>, and that result is not
<span class="emphasis"><em>ready</em></span>, sets any futures associated with
that task to <span class="emphasis"><em>ready</em></span> with a <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">broken_promise</span></code> exception as
the result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.get_future"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.get_future" title="Member Function get_future()">Member
Function <code class="computeroutput"><span class="identifier">get_future</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="identifier">get_future</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
was not associated with a result, allocate storage for a new
asynchronous result and associate it with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>. Returns a <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> associated
with the result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_already_retrieved</span></code> if
the future associated with the task has already been retrieved.
<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">bad_alloc</span></code> if any memory necessary
could not be allocated.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.set_value"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.set_value" title="Member Function set_value()">Member
Function <code class="computeroutput"><span class="identifier">set_value</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">set_value</span><span class="special">(</span><span class="identifier">R</span><span class="special">&&</span> <span class="identifier">r</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">set_value</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span><span class="special">&</span> <span class="identifier">r</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">promise</span><span class="special"><</span><span class="identifier">R</span><span class="special">&>::</span><span class="identifier">set_value</span><span class="special">(</span><span class="identifier">R</span><span class="special">&</span> <span class="identifier">r</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">promise</span><span class="special"><</span><span class="keyword">void</span><span class="special">>::</span><span class="identifier">set_value</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
was not associated with a result, allocate storage for a new
asynchronous result and associate it with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>. Store the value <code class="computeroutput"><span class="identifier">r</span></code> in the asynchronous result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>. Any threads blocked waiting
for the asynchronous result are woken.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
All futures waiting on the asynchronous result are <span class="emphasis"><em>ready</em></span>
and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.has_value" title="Member function has_value()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">has_value</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.has_value" title="Member function has_value()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">has_value</span><span class="special">()</span></code></a>
for those futures shall return <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise_already_satisfied</span></code> if
the result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is already <span class="emphasis"><em>ready</em></span>.
<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">bad_alloc</span></code> if the memory required
for storage of the result cannot be allocated. Any exception
thrown by the copy or move-constructor of <code class="computeroutput"><span class="identifier">R</span></code>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.set_exception"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.set_exception" title="Member Function set_exception()">Member
Function <code class="computeroutput"><span class="identifier">set_exception</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">set_exception</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">exception_ptr</span> <span class="identifier">e</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
If <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
was not associated with a result, allocate storage for a new
asynchronous result and associate it with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>. Store the exception <code class="computeroutput"><span class="identifier">e</span></code> in the asynchronous result
associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>. Any threads blocked waiting
for the asynchronous result are woken.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
All futures waiting on the asynchronous result are <span class="emphasis"><em>ready</em></span>
and <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future.has_exception" title="Member function has_exception()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">has_exception</span><span class="special">()</span></code></a>
or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future.has_exception" title="Member function has_exception()"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">>::</span><span class="identifier">has_exception</span><span class="special">()</span></code></a>
for those futures shall return <code class="computeroutput"><span class="keyword">true</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise_already_satisfied</span></code> if
the result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> is already <span class="emphasis"><em>ready</em></span>.
<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">bad_alloc</span></code> if the memory required
for storage of the result cannot be allocated.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.promise.set_wait_callback"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise.set_wait_callback" title="Member Function set_wait_callback()">Member
Function <code class="computeroutput"><span class="identifier">set_wait_callback</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">set_wait_callback</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Preconditions:</span></dt>
<dd><p>
The expression <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="identifier">t</span><span class="special">)</span></code> where <code class="computeroutput"><span class="identifier">t</span></code>
is a lvalue of type <a class="link" href="synchronization.html#thread.synchronization.futures.reference.promise" title="promise class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">promise</span></code></a> shall be well-formed.
Invoking a copy of <code class="computeroutput"><span class="identifier">f</span></code>
shall have the same effect as invoking <code class="computeroutput"><span class="identifier">f</span></code>
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Store a copy of <code class="computeroutput"><span class="identifier">f</span></code>
with the asynchronous result associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> as a <span class="emphasis"><em>wait callback</em></span>.
This will replace any existing wait callback store alongside
that result. If a thread subsequently calls one of the wait functions
on a <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a> associated
with this result, and the result is not <span class="emphasis"><em>ready</em></span>,
<code class="computeroutput"><span class="identifier">f</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span></code>
shall be invoked.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">bad_alloc</span></code> if memory cannot
be allocated for the required storage.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.futures.reference.packaged_task"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">packaged_task</span></code> class template</a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">R</span><span class="special">></span>
<span class="keyword">class</span> <span class="identifier">packaged_task</span>
<span class="special">{</span>
<span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">packaged_task</span><span class="special">&);//</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span>
<span class="identifier">packaged_task</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">packaged_task</span><span class="special">&);//</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="comment">// construction and destruction</span>
<span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">></span>
<span class="keyword">explicit</span> <span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">F</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">f</span><span class="special">);</span>
<span class="keyword">explicit</span> <span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">R</span><span class="special">(*</span><span class="identifier">f</span><span class="special">)());</span>
<span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">></span>
<span class="keyword">explicit</span> <span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">F</span><span class="special">&&</span> <span class="identifier">f</span><span class="special">);</span>
<span class="comment">// template <class F, class Allocator></span>
<span class="comment">// explicit packaged_task(F const& f, Allocator a);</span>
<span class="comment">// template <class F, class Allocator></span>
<span class="comment">// explicit packaged_task(F&& f, Allocator a);</span>
<span class="special">~</span><span class="identifier">packaged_task</span><span class="special">()</span>
<span class="special">{}</span>
<span class="comment">// move support</span>
<span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">packaged_task</span><span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="identifier">packaged_task</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">packaged_task</span><span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">packaged_task</span><span class="special">&</span> <span class="identifier">other</span><span class="special">);</span>
<span class="comment">// result retrieval</span>
<span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="identifier">get_future</span><span class="special">();</span>
<span class="comment">// execution</span>
<span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()();</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">set_wait_callback</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">);</span>
<span class="special">};</span>
</pre>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.packaged_task.task_constructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task.task_constructor" title="Task Constructor">Task
Constructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F</span><span class="special">></span>
<span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">F</span> <span class="keyword">const</span> <span class="special">&</span><span class="identifier">f</span><span class="special">);</span>
<span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">R</span><span class="special">(*</span><span class="identifier">f</span><span class="special">)());</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F</span><span class="special">></span>
<span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">F</span><span class="special">&&</span><span class="identifier">f</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Preconditions:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">f</span><span class="special">()</span></code>
is a valid expression with a return type convertible to <code class="computeroutput"><span class="identifier">R</span></code>. Invoking a copy of <code class="computeroutput"><span class="identifier">f</span></code> shall behave the same as
invoking <code class="computeroutput"><span class="identifier">f</span></code>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs a new <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a> with a
copy of <code class="computeroutput"><span class="identifier">f</span></code> stored
as the associated task.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by the copy (or move) constructor of <code class="computeroutput"><span class="identifier">f</span></code>. <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">bad_alloc</span></code>
if memory for the internal data structures could not be allocated.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.packaged_task.move_constructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task.move_constructor" title="Move Constructor">Move
Constructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">packaged_task</span><span class="special">(</span><span class="identifier">packaged_task</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Constructs a new <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a>, and transfers
ownership of the task associated with <code class="computeroutput"><span class="identifier">other</span></code>
to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
leaving <code class="computeroutput"><span class="identifier">other</span></code>
with no associated task.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
If the compiler does not support rvalue-references, this is implemented
using the boost.thread move emulation.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.packaged_task.move_assignment"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task.move_assignment" title="Move Assignment Operator">Move
Assignment Operator</a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">packaged_task</span><span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span><span class="identifier">packaged_task</span> <span class="special">&&</span> <span class="identifier">other</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Transfers ownership of the task associated with <code class="computeroutput"><span class="identifier">other</span></code> to <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>, leaving <code class="computeroutput"><span class="identifier">other</span></code>
with no associated task. If there was already a task associated
with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>,
and that task has not been invoked, sets any futures associated
with that task to <span class="emphasis"><em>ready</em></span> with a <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">broken_promise</span></code> exception as
the result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
If the compiler does not support rvalue-references, this is implemented
using the boost.thread move emulation.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.packaged_task.destructor"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task.destructor" title="Destructor">Destructor</a>
</h6></div></div></div>
<pre class="programlisting"><span class="special">~</span><span class="identifier">packaged_task</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Destroys <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
If there was a task associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>, and that task has not been
invoked, sets any futures associated with that task to <span class="emphasis"><em>ready</em></span>
with a <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">broken_promise</span></code>
exception as the result.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Nothing.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.packaged_task.get_future"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task.get_future" title="Member Function get_future()">Member
Function <code class="computeroutput"><span class="identifier">get_future</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="identifier">unique_future</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="identifier">get_future</span><span class="special">();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Returns a <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> associated
with the result of the task associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">task_moved</span></code> if ownership of
the task associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> has been moved to another
instance of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a>. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">future_already_retrieved</span></code> if
the future associated with the task has already been retrieved.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.packaged_task.call_operator"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task.call_operator" title="Member Function operator()()">Member
Function <code class="computeroutput"><span class="keyword">operator</span><span class="special">()()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()();</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Invoke the task associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> and store the result in the
corresponding future. If the task returns normally, the return
value is stored as the asynchronous result, otherwise the exception
thrown is stored. Any threads blocked waiting for the asynchronous
result associated with this task are woken.
</p></dd>
<dt><span class="term">Postconditions:</span></dt>
<dd><p>
All futures waiting on the asynchronous result are <span class="emphasis"><em>ready</em></span>
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">task_moved</span></code> if ownership of
the task associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> has been moved to another
instance of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a>. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">task_already_started</span></code> if the
task has already been invoked.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h6 class="title">
<a name="thread.synchronization.futures.reference.packaged_task.set_wait_callback"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task.set_wait_callback" title="Member Function set_wait_callback()">Member
Function <code class="computeroutput"><span class="identifier">set_wait_callback</span><span class="special">()</span></code></a>
</h6></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">set_wait_callback</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Preconditions:</span></dt>
<dd><p>
The expression <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="identifier">t</span><span class="special">)</span></code> where <code class="computeroutput"><span class="identifier">t</span></code>
is a lvalue of type <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a> shall
be well-formed. Invoking a copy of <code class="computeroutput"><span class="identifier">f</span></code>
shall have the same effect as invoking <code class="computeroutput"><span class="identifier">f</span></code>
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Store a copy of <code class="computeroutput"><span class="identifier">f</span></code>
with the task associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> as a <span class="emphasis"><em>wait callback</em></span>.
This will replace any existing wait callback store alongside
that task. If a thread subsequently calls one of the wait functions
on a <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a> associated
with this task, and the result of the task is not <span class="emphasis"><em>ready</em></span>,
<code class="computeroutput"><span class="identifier">f</span><span class="special">(*</span><span class="keyword">this</span><span class="special">)</span></code>
shall be invoked.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">task_moved</span></code> if ownership of
the task associated with <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> has been moved to another
instance of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.packaged_task" title="packaged_task class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">packaged_task</span></code></a>.
</p></dd>
</dl>
</div>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.futures.reference.wait_for_any"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.wait_for_any" title="Non-member function wait_for_any()">Non-member
function <code class="computeroutput"><span class="identifier">wait_for_any</span><span class="special">()</span></code></a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">></span>
<span class="identifier">Iterator</span> <span class="identifier">wait_for_any</span><span class="special">(</span><span class="identifier">Iterator</span> <span class="identifier">begin</span><span class="special">,</span><span class="identifier">Iterator</span> <span class="identifier">end</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">></span>
<span class="keyword">unsigned</span> <span class="identifier">wait_for_any</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F3</span><span class="special">></span>
<span class="keyword">unsigned</span> <span class="identifier">wait_for_any</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">,</span><span class="identifier">F3</span><span class="special">&</span> <span class="identifier">f3</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F4</span><span class="special">></span>
<span class="keyword">unsigned</span> <span class="identifier">wait_for_any</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">,</span><span class="identifier">F3</span><span class="special">&</span> <span class="identifier">f3</span><span class="special">,</span><span class="identifier">F4</span><span class="special">&</span> <span class="identifier">f4</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F4</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F5</span><span class="special">></span>
<span class="keyword">unsigned</span> <span class="identifier">wait_for_any</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">,</span><span class="identifier">F3</span><span class="special">&</span> <span class="identifier">f3</span><span class="special">,</span><span class="identifier">F4</span><span class="special">&</span> <span class="identifier">f4</span><span class="special">,</span><span class="identifier">F5</span><span class="special">&</span> <span class="identifier">f5</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Preconditions:</span></dt>
<dd><p>
The types <code class="computeroutput"><span class="identifier">Fn</span></code> shall
be specializations of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a>, and <code class="computeroutput"><span class="identifier">Iterator</span></code> shall be a forward iterator
with a <code class="computeroutput"><span class="identifier">value_type</span></code>
which is a specialization of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Waits until at least one of the specified futures is <span class="emphasis"><em>ready</em></span>.
</p></dd>
<dt><span class="term">Returns:</span></dt>
<dd><p>
The range-based overload returns an <code class="computeroutput"><span class="identifier">Iterator</span></code>
identifying the first future in the range that was detected as
<span class="emphasis"><em>ready</em></span>. The remaining overloads return the
zero-based index of the first future that was detected as <span class="emphasis"><em>ready</em></span>
(first parameter => 0, second parameter => 1, etc.).
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_interrupted</span></code> if the current
thread is interrupted. Any exception thrown by the <span class="emphasis"><em>wait
callback</em></span> associated with any of the futures being waited
for. <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">bad_alloc</span></code> if memory could not
be allocated for the internal wait structures.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">wait_for_any</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="thread.synchronization.futures.reference.wait_for_all"></a><a class="link" href="synchronization.html#thread.synchronization.futures.reference.wait_for_all" title="Non-member function wait_for_all()">Non-member
function <code class="computeroutput"><span class="identifier">wait_for_all</span><span class="special">()</span></code></a>
</h5></div></div></div>
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Iterator</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait_for_all</span><span class="special">(</span><span class="identifier">Iterator</span> <span class="identifier">begin</span><span class="special">,</span><span class="identifier">Iterator</span> <span class="identifier">end</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait_for_all</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F3</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait_for_all</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">,</span><span class="identifier">F3</span><span class="special">&</span> <span class="identifier">f3</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F4</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait_for_all</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">,</span><span class="identifier">F3</span><span class="special">&</span> <span class="identifier">f3</span><span class="special">,</span><span class="identifier">F4</span><span class="special">&</span> <span class="identifier">f4</span><span class="special">);</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F3</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F4</span><span class="special">,</span><span class="keyword">typename</span> <span class="identifier">F5</span><span class="special">></span>
<span class="keyword">void</span> <span class="identifier">wait_for_all</span><span class="special">(</span><span class="identifier">F1</span><span class="special">&</span> <span class="identifier">f1</span><span class="special">,</span><span class="identifier">F2</span><span class="special">&</span> <span class="identifier">f2</span><span class="special">,</span><span class="identifier">F3</span><span class="special">&</span> <span class="identifier">f3</span><span class="special">,</span><span class="identifier">F4</span><span class="special">&</span> <span class="identifier">f4</span><span class="special">,</span><span class="identifier">F5</span><span class="special">&</span> <span class="identifier">f5</span><span class="special">);</span>
</pre>
<div class="variablelist">
<p class="title"><b></b></p>
<dl>
<dt><span class="term">Preconditions:</span></dt>
<dd><p>
The types <code class="computeroutput"><span class="identifier">Fn</span></code> shall
be specializations of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a>, and <code class="computeroutput"><span class="identifier">Iterator</span></code> shall be a forward iterator
with a <code class="computeroutput"><span class="identifier">value_type</span></code>
which is a specialization of <a class="link" href="synchronization.html#thread.synchronization.futures.reference.unique_future" title="unique_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">unique_future</span></code></a> or <a class="link" href="synchronization.html#thread.synchronization.futures.reference.shared_future" title="shared_future class template"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">shared_future</span></code></a>.
</p></dd>
<dt><span class="term">Effects:</span></dt>
<dd><p>
Waits until all of the specified futures are <span class="emphasis"><em>ready</em></span>.
</p></dd>
<dt><span class="term">Throws:</span></dt>
<dd><p>
Any exceptions thrown by a call to <code class="computeroutput"><span class="identifier">wait</span><span class="special">()</span></code> on the specified futures.
</p></dd>
<dt><span class="term">Notes:</span></dt>
<dd><p>
<code class="computeroutput"><span class="identifier">wait_for_all</span><span class="special">()</span></code>
is an <span class="emphasis"><em>interruption point</em></span>.
</p></dd>
</dl>
</div>
</div>
</div>
</div>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2007 -8 Anthony Williams<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
</p>
</div></td>
</tr></table>
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