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<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html><head><title>QThread Class Reference</title><style>h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm }
a:link { color: #004faf; text-decoration: none }
a:visited { color: #672967; text-decoration: none }
td.postheader { font-family: sans-serif }
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body { background: #ffffff; color: black; }
</style></head><body><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr /><td align="left" valign="top" width="32"><img align="left" border="0" height="32" src="images/rb-logo.png" width="32" /></td><td width="1">  </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a> · <a href="classes.html"><font color="#004faf">All Classes</font></a> · <a href="modules.html"><font color="#004faf">Modules</font></a></td></table><h1 align="center">QThread Class Reference<br /><sup><sup>[<a href="qtcore.html">QtCore</a> module]</sup></sup></h1><p>The QThread class provides a platform-independent way to manage
threads. <a href="#details">More...</a></p>
<p>Inherits <a href="qobject.html">QObject</a>.</p><h3>Types</h3><ul><li><div class="fn" />enum <b><a href="qthread.html#Priority-enum">Priority</a></b> { IdlePriority, LowestPriority, LowPriority, NormalPriority, ..., InheritPriority }</li></ul><h3>Methods</h3><ul><li><div class="fn" /><b><a href="qthread.html#QThread">__init__</a></b> (<i>self</i>, QObject <i>parent</i> = None)</li><li><div class="fn" />int <b><a href="qthread.html#exec">exec_</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qthread.html#exit">exit</a></b> (<i>self</i>, int <i>returnCode</i> = 0)</li><li><div class="fn" />bool <b><a href="qthread.html#isFinished">isFinished</a></b> (<i>self</i>)</li><li><div class="fn" />bool <b><a href="qthread.html#isRunning">isRunning</a></b> (<i>self</i>)</li><li><div class="fn" />Priority <b><a href="qthread.html#priority">priority</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qthread.html#quit">quit</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qthread.html#run">run</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qthread.html#setPriority">setPriority</a></b> (<i>self</i>, Priority <i>priority</i>)</li><li><div class="fn" /><b><a href="qthread.html#setStackSize">setStackSize</a></b> (<i>self</i>, int <i>stackSize</i>)</li><li><div class="fn" />int <b><a href="qthread.html#stackSize">stackSize</a></b> (<i>self</i>)</li><li><div class="fn" /><b><a href="qthread.html#start">start</a></b> (<i>self</i>, Priority <i>priority</i> = QThread.InheritPriority)</li><li><div class="fn" /><b><a href="qthread.html#terminate">terminate</a></b> (<i>self</i>)</li><li><div class="fn" />bool <b><a href="qthread.html#wait">wait</a></b> (<i>self</i>, int <i>msecs</i> = ULONG_MAX)</li></ul><h3>Static Methods</h3><ul><li><div class="fn" />QThread <b><a href="qthread.html#currentThread">currentThread</a></b> ()</li><li><div class="fn" />int <b><a href="qthread.html#currentThreadId">currentThreadId</a></b> ()</li><li><div class="fn" />int <b><a href="qthread.html#idealThreadCount">idealThreadCount</a></b> ()</li><li><div class="fn" /><b><a href="qthread.html#msleep">msleep</a></b> (int)</li><li><div class="fn" /><b><a href="qthread.html#setTerminationEnabled">setTerminationEnabled</a></b> (bool <i>enabled</i> = True)</li><li><div class="fn" /><b><a href="qthread.html#sleep">sleep</a></b> (int)</li><li><div class="fn" /><b><a href="qthread.html#usleep">usleep</a></b> (int)</li><li><div class="fn" /><b><a href="qthread.html#yieldCurrentThread">yieldCurrentThread</a></b> ()</li></ul><h3>Qt Signals</h3><ul><li><div class="fn" />void <b><a href="qthread.html#finished">finished</a></b> ()</li><li><div class="fn" />void <b><a href="qthread.html#started">started</a></b> ()</li><li><div class="fn" />void <b><a href="qthread.html#terminated">terminated</a></b> ()</li></ul><a name="details" /><hr /><h2>Detailed Description</h2><p>The QThread class provides a platform-independent way to manage
threads.</p>
<p>A QThread object manages one thread of control within the
program. QThreads begin executing in <a href="qthread.html#run">run</a>(). By default, <a href="qthread.html#run">run</a>() starts the event loop by calling
<a href="qthread.html#exec">exec_</a>() and runs a Qt event loop
inside the thread.</p>
<p>You can use worker objects by moving them to the thread using
<a href="qobject.html#moveToThread">QObject.moveToThread</a>().</p>
<pre class="cpp">
<span class="keyword">class</span> Worker : <span class="keyword">public</span> <span class="type"><a href="qobject.html">QObject</a></span>
{
Q_OBJECT
<span class="type">QThread</span> workerThread;
<span class="keyword">public</span> <span class="keyword">slots</span>:
<span class="type">void</span> doWork(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>parameter) {
<span class="comment">// ...</span>
<span class="keyword">emit</span> resultReady(result);
}
<span class="keyword">signals</span>:
<span class="type">void</span> resultReady(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>result);
};
<span class="keyword">class</span> Controller : <span class="keyword">public</span> <span class="type"><a href="qobject.html">QObject</a></span>
{
Q_OBJECT
<span class="type">QThread</span> workerThread;
<span class="keyword">public</span>:
Controller() {
Worker <span class="operator">*</span>worker <span class="operator">=</span> <span class="keyword">new</span> Worker;
worker<span class="operator">-</span><span class="operator">></span>moveToThread(<span class="operator">&</span>workerThread);
connect(workerThread<span class="operator">,</span> SIGNAL(finished())<span class="operator">,</span> worker<span class="operator">,</span> SLOT(deleteLater()));
connect(<span class="keyword">this</span><span class="operator">,</span> SIGNAL(operate(<span class="type"><a href="qstring.html">QString</a></span>))<span class="operator">,</span> worker<span class="operator">,</span> SLOT(doWork(<span class="type"><a href="qstring.html">QString</a></span>)));
connect(worker<span class="operator">,</span> SIGNAL(resultReady(<span class="type"><a href="qstring.html">QString</a></span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(handleResults(<span class="type"><a href="qstring.html">QString</a></span>)));
workerThread<span class="operator">.</span>start();
}
<span class="operator">~</span>Controller() {
workerThread<span class="operator">.</span>quit();
workerThread<span class="operator">.</span>wait();
}
<span class="keyword">public</span> <span class="keyword">slots</span>:
<span class="type">void</span> handleResults(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>);
<span class="keyword">signals</span>:
<span class="type">void</span> operate(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>);
};
</pre>
<p>The code inside the Worker's slot would then execute in a
separate thread. However, you are free to connect the Worker's
slots to any signal, from any object, in any thread. It is safe to
connect signals and slots across different threads, thanks to a
mechanism called <a href="qt.html#ConnectionType-enum">queued
connections</a>.</p>
<p>Another way to make code run in a separate thread, is to
subclass QThread and reimplement <a href="qthread.html#run">run</a>(). For example:</p>
<pre class="cpp">
<span class="keyword">class</span> WorkerThread : <span class="keyword">public</span> <span class="type">QThread</span>
{
Q_OBJECT
<span class="type">void</span> run() {
<span class="type"><a href="qstring.html">QString</a></span> result;
<span class="comment">/* expensive or blocking operation */</span>
<span class="keyword">emit</span> resultReady(result);
}
<span class="keyword">signals</span>:
<span class="type">void</span> resultReady(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>s);
};
<span class="type">void</span> MyObject<span class="operator">.</span>startWorkInAThread()
{
WorkerThread <span class="operator">*</span>workerThread <span class="operator">=</span> <span class="keyword">new</span> WorkerThread(<span class="keyword">this</span>);
connect(workerThread<span class="operator">,</span> SIGNAL(resultReady(<span class="type"><a href="qstring.html">QString</a></span>))<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(handleResults(<span class="type"><a href="qstring.html">QString</a></span>)));
connect(workerThread<span class="operator">,</span> SIGNAL(finished())<span class="operator">,</span> workerThread<span class="operator">,</span> SLOT(deleteLater()));
workerThread<span class="operator">-</span><span class="operator">></span>start();
}
</pre>
<p>In that example, the thread will exit after the run function has
returned. There will not be any event loop running in the thread
unless you call <a href="qthread.html#exec">exec_</a>().</p>
<p>It is important to remember that a QThread instance <a href="qobject.html#thread-affinity">lives in</a> the old thread that
instantiated it, not in the new thread that calls <a href="qthread.html#run">run</a>(). This means that all of QThread's
queued slots will execute in the old thread. Thus, a developer who
wishes to invoke slots in the new thread must use the worker-object
approach; new slots should not be implemented directly into a
subclassed QThread.</p>
<p>When subclassing QThread, keep in mind that the constructor
executes in the old thread while <a href="qthread.html#run">run</a>() executes in the new thread. If a
member variable is accessed from both functions, then the variable
is accessed from two different threads. Check that it is safe to do
so.</p>
<p><b>Note:</b> Care must be taken when interacting with objects
across different threads. See <a href="threads-synchronizing.html">Synchronizing Threads</a> for
details.</p>
<a id="managing-threads" name="managing-threads" />
<h3>Managing threads</h3>
<p>QThread will notifiy you via a signal when the thread is
<a href="qthread.html#started">started</a>(), <a href="qthread.html#finished">finished</a>(), and <a href="qthread.html#terminated">terminated</a>(), or you can use <a href="qthread.html#isFinished">isFinished</a>() and <a href="qthread.html#isRunning">isRunning</a>() to query the state of the
thread.</p>
<p>You can stop the thread by calling <a href="qthread.html#exit">exit</a>() or <a href="qthread.html#quit">quit</a>(). In extreme cases, you may want to
forcibly <a href="qthread.html#terminate">terminate</a>() an
executing thread. However, doing so is dangerous and discouraged.
Please read the documentation for <a href="qthread.html#terminate">terminate</a>() and <a href="qthread.html#setTerminationEnabled">setTerminationEnabled</a>()
for detailed information.</p>
<p>From Qt 4.8 onwards, it is possible to deallocate objects that
live in a thread that has just ended, by connecting the <a href="qthread.html#finished">finished</a>() signal to <a href="qobject.html#deleteLater">QObject.deleteLater</a>().</p>
<p>Use <a href="qthread.html#wait">wait</a>() to block the calling
thread, until the other thread has finished execution (or until a
specified time has passed).</p>
<p>The static functions <a href="qthread.html#currentThreadId">currentThreadId</a>() and <a href="qthread.html#currentThread">currentThread</a>() return identifiers
for the currently executing thread. The former returns a platform
specific ID for the thread; the latter returns a QThread
pointer.</p>
<p>To choose the name that your thread will be given (as identified
by the command <tt>ps -L</tt> on Linux, for example), you can call
<a href="qobject.html#objectName-prop">setObjectName()</a> before
starting the thread. If you don't call <a href="qobject.html#objectName-prop">setObjectName()</a>, the name given
to your thread will be the class name of the runtime type of your
thread object (for example, <tt>"RenderThread"</tt> in the case of
the <a href="threads-mandelbrot.html">Mandelbrot Example</a>, as
that is the name of the QThread subclass). Note that this is
currently not available with release builds on Windows.</p>
<p>QThread also provides static, platform independent sleep
functions: <a href="qthread.html#sleep">sleep</a>(), <a href="qthread.html#msleep">msleep</a>(), and <a href="qthread.html#usleep">usleep</a>() allow full second, millisecond,
and microsecond resolution respectively.</p>
<p><b>Note:</b> <a href="qthread.html#wait">wait</a>() and the
<a href="qthread.html#sleep">sleep</a>() functions should be
unnecessary in general, since Qt is an event-driven framework.
Instead of <a href="qthread.html#wait">wait</a>(), consider
listening for the <a href="qthread.html#finished">finished</a>()
signal. Instead of the <a href="qthread.html#sleep">sleep</a>()
functions, consider using <a href="qtimer.html">QTimer</a>.</p>
<p>{Mandelbrot Example}, {Semaphores Example}, {Wait Conditions
Example}</p>
<hr /><h2>Type Documentation</h2><h3 class="fn"><a name="Priority-enum" />QThread.Priority</h3><p>This enum type indicates how the operating system should
schedule newly created threads.</p>
<table class="valuelist">
<tr class="odd" valign="top">
<th class="tblConst">Constant</th>
<th class="tblval">Value</th>
<th class="tbldscr">Description</th>
</tr>
<tr>
<td class="topAlign"><tt>QThread.IdlePriority</tt></td>
<td class="topAlign"><tt>0</tt></td>
<td class="topAlign">scheduled only when no other threads are
running.</td>
</tr>
<tr>
<td class="topAlign"><tt>QThread.LowestPriority</tt></td>
<td class="topAlign"><tt>1</tt></td>
<td class="topAlign">scheduled less often than LowPriority.</td>
</tr>
<tr>
<td class="topAlign"><tt>QThread.LowPriority</tt></td>
<td class="topAlign"><tt>2</tt></td>
<td class="topAlign">scheduled less often than NormalPriority.</td>
</tr>
<tr>
<td class="topAlign"><tt>QThread.NormalPriority</tt></td>
<td class="topAlign"><tt>3</tt></td>
<td class="topAlign">the default priority of the operating
system.</td>
</tr>
<tr>
<td class="topAlign"><tt>QThread.HighPriority</tt></td>
<td class="topAlign"><tt>4</tt></td>
<td class="topAlign">scheduled more often than NormalPriority.</td>
</tr>
<tr>
<td class="topAlign"><tt>QThread.HighestPriority</tt></td>
<td class="topAlign"><tt>5</tt></td>
<td class="topAlign">scheduled more often than HighPriority.</td>
</tr>
<tr>
<td class="topAlign"><tt>QThread.TimeCriticalPriority</tt></td>
<td class="topAlign"><tt>6</tt></td>
<td class="topAlign">scheduled as often as possible.</td>
</tr>
<tr>
<td class="topAlign"><tt>QThread.InheritPriority</tt></td>
<td class="topAlign"><tt>7</tt></td>
<td class="topAlign">use the same priority as the creating thread.
This is the default.</td>
</tr>
</table>
<hr /><h2>Method Documentation</h2><h3 class="fn"><a name="QThread" />QThread.__init__ (<i>self</i>, <a href="qobject.html">QObject</a> <i>parent</i> = None)</h3><p>The <i>parent</i> argument, if not None, causes <i>self</i> to be owned by Qt instead of PyQt.</p><p>Constructs a new <a href="qthread.html">QThread</a> to manage a
new thread. The <i>parent</i> takes ownership of the <a href="qthread.html">QThread</a>. The thread does not begin executing
until <a href="qthread.html#start">start</a>() is called.</p>
<p><b>See also</b> <a href="qthread.html#start">start</a>().</p>
<h3 class="fn"><a name="currentThread" /><a href="qthread.html">QThread</a> QThread.currentThread ()</h3><p>Returns a pointer to a <a href="qthread.html">QThread</a> which
manages the currently executing thread.</p>
<h3 class="fn"><a name="currentThreadId" />int QThread.currentThreadId ()</h3><p>Returns the thread handle of the currently executing thread.</p>
<p><b>Warning:</b> The handle returned by this function is used for
internal purposes and should not be used in any application
code.</p>
<p><b>Warning:</b> On Windows, the returned value is a
pseudo-handle for the current thread. It can't be used for
numerical comparison. i.e., this function returns the DWORD
(Windows-Thread ID) returned by the Win32 function
getCurrentThreadId(), not the HANDLE (Windows-Thread HANDLE)
returned by the Win32 function getCurrentThread().</p>
<h3 class="fn"><a name="exec" />int QThread.exec_ (<i>self</i>)</h3><p>Enters the event loop and waits until <a href="qthread.html#exit">exit</a>() is called, returning the value that
was passed to <a href="qthread.html#exit">exit</a>(). The value
returned is 0 if <a href="qthread.html#exit">exit</a>() is called
via <a href="qthread.html#quit">quit</a>().</p>
<p>This function is meant to be called from within <a href="qthread.html#run">run</a>(). It is necessary to call this function
to start event handling.</p>
<p><b>See also</b> <a href="qthread.html#quit">quit</a>() and
<a href="qthread.html#exit">exit</a>().</p>
<h3 class="fn"><a name="exit" />QThread.exit (<i>self</i>, int <i>returnCode</i> = 0)</h3><p>Tells the thread's event loop to exit with a return code.</p>
<p>After calling this function, the thread leaves the event loop
and returns from the call to <a href="qeventloop.html#exec">QEventLoop.exec</a>(). The <a href="qeventloop.html#exec">QEventLoop.exec</a>() function returns
<i>returnCode</i>.</p>
<p>By convention, a <i>returnCode</i> of 0 means success, any
non-zero value indicates an error.</p>
<p>Note that unlike the C library function of the same name, this
function <i>does</i> return to the caller -- it is event processing
that stops.</p>
<p>No QEventLoops will be started anymore in this thread until
<a href="qthread.html#exec">QThread.exec</a>() has been called
again. If the eventloop in <a href="qthread.html#exec">QThread.exec</a>() is not running then the
next call to <a href="qthread.html#exec">QThread.exec</a>() will
also return immediately.</p>
<p><b>See also</b> <a href="qthread.html#quit">quit</a>() and
<a href="qeventloop.html">QEventLoop</a>.</p>
<h3 class="fn"><a name="idealThreadCount" />int QThread.idealThreadCount ()</h3><p>Returns the ideal number of threads that can be run on the
system. This is done querying the number of processor cores, both
real and logical, in the system. This function returns -1 if the
number of processor cores could not be detected.</p>
<h3 class="fn"><a name="isFinished" />bool QThread.isFinished (<i>self</i>)</h3><p>Returns true if the thread is finished; otherwise returns
false.</p>
<p><b>See also</b> <a href="qthread.html#isRunning">isRunning</a>().</p>
<h3 class="fn"><a name="isRunning" />bool QThread.isRunning (<i>self</i>)</h3><p>Returns true if the thread is running; otherwise returns
false.</p>
<p><b>See also</b> <a href="qthread.html#isFinished">isFinished</a>().</p>
<h3 class="fn"><a name="msleep" />QThread.msleep (int)</h3><p>Forces the current thread to sleep for <i>msecs</i>
milliseconds.</p>
<p><b>See also</b> <a href="qthread.html#sleep">sleep</a>() and
<a href="qthread.html#usleep">usleep</a>().</p>
<h3 class="fn"><a name="priority" /><a href="qthread.html#Priority-enum">Priority</a> QThread.priority (<i>self</i>)</h3><p>Returns the priority for a running thread. If the thread is not
running, this function returns <tt>InheritPriority</tt>.</p>
<p>This function was introduced in Qt 4.1.</p>
<p><b>See also</b> <a href="qthread.html#Priority-enum">Priority</a>, <a href="qthread.html#setPriority">setPriority</a>(), and <a href="qthread.html#start">start</a>().</p>
<h3 class="fn"><a name="quit" />QThread.quit (<i>self</i>)</h3><p>This method is also a Qt slot with the C++ signature <tt>void quit()</tt>.</p><p>Tells the thread's event loop to exit with return code 0
(success). Equivalent to calling QThread.exit(0).</p>
<p>This function does nothing if the thread does not have an event
loop.</p>
<p><b>See also</b> <a href="qthread.html#exit">exit</a>() and
<a href="qeventloop.html">QEventLoop</a>.</p>
<h3 class="fn"><a name="run" />QThread.run (<i>self</i>)</h3><p>The starting point for the thread. After calling <a href="qthread.html#start">start</a>(), the newly created thread calls
this function. The default implementation simply calls <a href="qthread.html#exec">exec_</a>().</p>
<p>You can reimplement this function to facilitate advanced thread
management. Returning from this method will end the execution of
the thread.</p>
<p><b>See also</b> <a href="qthread.html#start">start</a>() and
<a href="qthread.html#wait">wait</a>().</p>
<h3 class="fn"><a name="setPriority" />QThread.setPriority (<i>self</i>, <a href="qthread.html#Priority-enum">Priority</a> <i>priority</i>)</h3><p>This function sets the <i>priority</i> for a running thread. If
the thread is not running, this function does nothing and returns
immediately. Use <a href="qthread.html#start">start</a>() to start
a thread with a specific priority.</p>
<p>The <i>priority</i> argument can be any value in the
<tt>QThread.Priority</tt> enum except for
<tt>InheritPriorty</tt>.</p>
<p>The effect of the <i>priority</i> parameter is dependent on the
operating system's scheduling policy. In particular, the
<i>priority</i> will be ignored on systems that do not support
thread priorities (such as on Linux, see
http://linux.die.net/man/2/sched_setscheduler for more
details).</p>
<p>This function was introduced in Qt 4.1.</p>
<p><b>See also</b> <a href="qthread.html#Priority-enum">Priority</a>, <a href="qthread.html#priority">priority</a>(), and <a href="qthread.html#start">start</a>().</p>
<h3 class="fn"><a name="setStackSize" />QThread.setStackSize (<i>self</i>, int <i>stackSize</i>)</h3><p>Sets the maximum stack size for the thread to <i>stackSize</i>.
If <i>stackSize</i> is greater than zero, the maximum stack size is
set to <i>stackSize</i> bytes, otherwise the maximum stack size is
automatically determined by the operating system.</p>
<p><b>Warning:</b> Most operating systems place minimum and maximum
limits on thread stack sizes. The thread will fail to start if the
stack size is outside these limits.</p>
<p><b>See also</b> <a href="qthread.html#stackSize">stackSize</a>().</p>
<h3 class="fn"><a name="setTerminationEnabled" />QThread.setTerminationEnabled (bool <i>enabled</i> = True)</h3><p>Enables or disables termination of the current thread based on
the <i>enabled</i> parameter. The thread must have been started by
<a href="qthread.html">QThread</a>.</p>
<p>When <i>enabled</i> is false, termination is disabled. Future
calls to <a href="qthread.html#terminate">QThread.terminate</a>()
will return immediately without effect. Instead, the termination is
deferred until termination is enabled.</p>
<p>When <i>enabled</i> is true, termination is enabled. Future
calls to <a href="qthread.html#terminate">QThread.terminate</a>()
will terminate the thread normally. If termination has been
deferred (i.e. <a href="qthread.html#terminate">QThread.terminate</a>() was called with
termination disabled), this function will terminate the calling
thread <i>immediately</i>. Note that this function will not return
in this case.</p>
<p><b>See also</b> <a href="qthread.html#terminate">terminate</a>().</p>
<h3 class="fn"><a name="sleep" />QThread.sleep (int)</h3><p>Forces the current thread to sleep for <i>secs</i> seconds.</p>
<p><b>See also</b> <a href="qthread.html#msleep">msleep</a>() and
<a href="qthread.html#usleep">usleep</a>().</p>
<h3 class="fn"><a name="stackSize" />int QThread.stackSize (<i>self</i>)</h3><p>Returns the maximum stack size for the thread (if set with
<a href="qthread.html#setStackSize">setStackSize</a>()); otherwise
returns zero.</p>
<p><b>See also</b> <a href="qthread.html#setStackSize">setStackSize</a>().</p>
<h3 class="fn"><a name="start" />QThread.start (<i>self</i>, <a href="qthread.html#Priority-enum">Priority</a> <i>priority</i> = QThread.InheritPriority)</h3><p>This method is also a Qt slot with the C++ signature <tt>void start(QThread::Priority = QThread.InheritPriority)</tt>.</p><p>Begins execution of the thread by calling <a href="qthread.html#run">run</a>(). The operating system will schedule
the thread according to the <i>priority</i> parameter. If the
thread is already running, this function does nothing.</p>
<p>The effect of the <i>priority</i> parameter is dependent on the
operating system's scheduling policy. In particular, the
<i>priority</i> will be ignored on systems that do not support
thread priorities (such as on Linux, see
http://linux.die.net/man/2/sched_setscheduler for more
details).</p>
<p><b>See also</b> <a href="qthread.html#run">run</a>() and
<a href="qthread.html#terminate">terminate</a>().</p>
<h3 class="fn"><a name="terminate" />QThread.terminate (<i>self</i>)</h3><p>This method is also a Qt slot with the C++ signature <tt>void terminate()</tt>.</p><p>Terminates the execution of the thread. The thread may or may
not be terminated immediately, depending on the operating system's
scheduling policies. Listen for the <a href="qthread.html#terminated">terminated</a>() signal, or use <a href="qthread.html#wait">QThread.wait</a>() after terminate(), to be
sure.</p>
<p>When the thread is terminated, all threads waiting for the
thread to finish will be woken up.</p>
<p><b>Warning:</b> This function is dangerous and its use is
discouraged. The thread can be terminated at any point in its code
path. Threads can be terminated while modifying data. There is no
chance for the thread to clean up after itself, unlock any held
mutexes, etc. In short, use this function only if absolutely
necessary.</p>
<p>Termination can be explicitly enabled or disabled by calling
<a href="qthread.html#setTerminationEnabled">QThread.setTerminationEnabled</a>().
Calling this function while termination is disabled results in the
termination being deferred, until termination is re-enabled. See
the documentation of <a href="qthread.html#setTerminationEnabled">QThread.setTerminationEnabled</a>()
for more information.</p>
<p><b>See also</b> <a href="qthread.html#setTerminationEnabled">setTerminationEnabled</a>().</p>
<h3 class="fn"><a name="usleep" />QThread.usleep (int)</h3><p>Forces the current thread to sleep for <i>usecs</i>
microseconds.</p>
<p><b>See also</b> <a href="qthread.html#sleep">sleep</a>() and
<a href="qthread.html#msleep">msleep</a>().</p>
<h3 class="fn"><a name="wait" />bool QThread.wait (<i>self</i>, int <i>msecs</i> = ULONG_MAX)</h3><p>Blocks the thread until either of these conditions is met:</p>
<ul>
<li>The thread associated with this <a href="qthread.html">QThread</a> object has finished execution (i.e. when
it returns from <a href="qthread.html#run">run</a>()). This
function will return true if the thread has finished. It also
returns true if the thread has not been started yet.</li>
<li><i>time</i> milliseconds has elapsed. If <i>time</i> is
ULONG_MAX (the default), then the wait will never timeout (the
thread must return from <a href="qthread.html#run">run</a>()). This
function will return false if the wait timed out.</li>
</ul>
<p>This provides similar functionality to the POSIX
<tt>pthread_join()</tt> function.</p>
<p><b>See also</b> <a href="qthread.html#sleep">sleep</a>() and
<a href="qthread.html#terminate">terminate</a>().</p>
<h3 class="fn"><a name="yieldCurrentThread" />QThread.yieldCurrentThread ()</h3><p>Yields execution of the current thread to another runnable
thread, if any. Note that the operating system decides to which
thread to switch.</p>
<hr /><h2>Qt Signal Documentation</h2><h3 class="fn"><a name="finished" />void finished ()</h3><p>This is the default overload of this signal.</p><p>This signal is emitted when the thread has finished
executing.</p>
<p><b>See also</b> <a href="qthread.html#started">started</a>() and
<a href="qthread.html#terminated">terminated</a>().</p>
<h3 class="fn"><a name="started" />void started ()</h3><p>This is the default overload of this signal.</p><p>This signal is emitted when the thread starts executing.</p>
<p><b>See also</b> <a href="qthread.html#finished">finished</a>()
and <a href="qthread.html#terminated">terminated</a>().</p>
<h3 class="fn"><a name="terminated" />void terminated ()</h3><p>This is the default overload of this signal.</p><p>This signal is emitted when the thread is terminated.</p>
<p><b>See also</b> <a href="qthread.html#started">started</a>() and
<a href="qthread.html#finished">finished</a>().</p>
<address><hr /><div align="center"><table border="0" cellspacing="0" width="100%"><tr class="address"><td align="left" width="25%">PyQt 4.11.2 for X11</td><td align="center" width="50%">Copyright © <a href="http://www.riverbankcomputing.com">Riverbank Computing Ltd</a> and <a href="http://qt.digia.com">Digia</a> 2014</td><td align="right" width="25%">Qt 4.8.6</td></tr></table></div></address></body></html>
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