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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<h1 align=center>QThread Class Reference</h1><br clear="all">
<p>
The QThread class provides platform-independent threads
<a href="#details">More...</a>
<p>
<code>#include <<a href="qthread-h.html">qthread.h</a>></code>
<p>
Inherits <a href="qt.html">Qt</a>.
<p><a href="qthread-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li><div class="fn"><a href="#7aabff"><b>QThread</b></a>()</div>
<li><div class="fn">virtual<a href="#54ba48"><b>~QThread</b></a>()</div>
<li><div class="fn">bool<a href="#5dec86"><b>wait</b></a>(unsignedlongtime=ULONG_MAX)</div>
<li><div class="fn">void<a href="#536ef2"><b>start</b></a>()</div>
<li><div class="fn">bool<a href="#be34d4"><b>finished</b></a>()const</div>
<li><div class="fn">bool<a href="#a0d1da"><b>running</b></a>()const</div>
</ul>
<h2>Static Public Members</h2>
<ul>
<li><div class="fn">HANDLE<a href="#ab0cf1"><b>currentThread</b></a>()</div>
<li><div class="fn">void<a href="#f0670e"><b>postEvent</b></a>(QObject*, QEvent*)</div>
<li><div class="fn">void<a href="#5782c2"><b>exit</b></a>()</div>
</ul>
<h2>Protected Members</h2>
<ul>
<li><div class="fn">virtualvoid<a href="#f1c9f8"><b>run</b></a>()</div>
</ul>
<h2>Static Protected Members</h2>
<ul>
<li><div class="fn">void<a href="#bd7b82"><b>sleep</b></a>(unsignedlong)</div>
<li><div class="fn">void<a href="#c0539e"><b>msleep</b></a>(unsignedlong)</div>
<li><div class="fn">void<a href="#5eabb5"><b>usleep</b></a>(unsignedlong)</div>
</ul>
<hr><h2><a name="details"></a>Detailed Description</h2>
The QThread class provides platform-independent threads
<p>
A QThread represents a separate thread of control within the program;
it shares all data with other threads within the process but
executes independently in the way that a separate program does on
a multitasking operating system. Instead of starting in main(),
however, QThreads begin executing in <a href="#f1c9f8">run</a>(), which you inherit
to provide your code. For instance:
<p><pre> class MyThread : public QThread {
public:
virtual void run();
};
void MyThread::run()
{
for(int count=0;count<20;count++) {
<a href="#bd7b82">sleep</a>(1);
<a href="qapplication.html#72e78c">qDebug</a>("Ping!");
}
}
int main()
{
MyThread a;
MyThread b;
a.<a href="#536ef2">start</a>();
b.<a href="#536ef2">start</a>();
a.<a href="#5dec86">wait</a>();
b.<a href="#5dec86">wait</a>();
}
</pre>
<p>This will start two threads, each of which writes Ping! 20 times
to the screen and exits. The <a href="#5dec86">wait</a>() calls at the end of main() are
necessary because exiting main() ends the program, unceremoniously
killing all other threads. Each MyThread stops executing when it
reaches the end of MyThread::run(), just as an application does when
it leaves main().
<p>See also the paragraph on <a href="threads.html">Thread Support in Qt</a>
<hr><h2>Member Function Documentation</h2>
<h3 class="fn"><a name="7aabff"></a>QThread::QThread()</h3>
<p>Constructs a new thread. The thread does not actually begin executing
until <a href="#536ef2">start</a>() is called.
<h3 class="fn"><a name="54ba48"></a>QThread::~QThread() <code>[virtual]</code></h3>
<p>QThread destructor. Note that deleting a QThread object will not stop
the execution of the thread it represents, and that deleting a QThread
object while the thread is running is unsafe.
<h3 class="fn">HANDLE<a name="ab0cf1"></a>QThread::currentThread() <code>[static]</code></h3>
<p>This returns the thread handle of the currently executing thread. The
handle returned by this function is used for internal reasons and
should not be used in any application code.
On Windows, the returned value is a pseudo handle for the current thread,
and it can not be used for numerical comparison.
<h3 class="fn">void<a name="5782c2"></a>QThread::exit() <code>[static]</code></h3>
<p>Ends execution of the calling thread and wakes up any threads waiting
for its termination.
<h3 class="fn">bool<a name="be34d4"></a>QThread::finished()const</h3>
<p>Returns TRUE is the thread is finished.
<h3 class="fn">void<a name="c0539e"></a>QThread::msleep(unsignedlongmsecs) <code>[staticprotected]</code></h3>
<p>System independent sleep. This causes the current thread to sleep for
<em>msecs</em> milliseconds.
<h3 class="fn">void<a name="f0670e"></a>QThread::postEvent(<a href="qobject.html">QObject</a>*receiver, <a href="qevent.html">QEvent</a>*event) <code>[static]</code></h3>
<p>Provides a way of posting an event from a thread which is not the
event thread to an object. The event is put into a queue, then the
event thread is woken which then sends the event to the object.
It is important to note that the event handler for the event, when called,
will be called from the event thread and not from the thread calling
QThread::postEvent().
<p>Same as with <a href="qapplication.html#96d77e">QApplication::postEvent()</a>, <em>event</em> must be allocated on the
heap, as it is deleted when the event has been posted.
<h3 class="fn">void<a name="f1c9f8"></a>QThread::run() <code>[virtualprotected]</code></h3>
<p>This method is pure virtual, and it must be implemented in derived classes
in order to do useful work. Returning from this method will end execution
of the thread.
<h3 class="fn">bool<a name="a0d1da"></a>QThread::running()const</h3>
<p>Returns TRUE if the thread is running.
<h3 class="fn">void<a name="bd7b82"></a>QThread::sleep(unsignedlongsecs) <code>[staticprotected]</code></h3>
<p>System independent sleep. This causes the current thread to sleep for
<em>secs</em> seconds.
<h3 class="fn">void<a name="536ef2"></a>QThread::start()</h3>
<p>This begins actual execution of the thread by calling <a href="#f1c9f8">run</a>(),
which should be reimplemented in a QThread subclass to contain your code.
If you try to start a thread that is already running, this call will
wait until the thread has finished, and then restart the thread.
<h3 class="fn">void<a name="5eabb5"></a>QThread::usleep(unsignedlongusecs) <code>[staticprotected]</code></h3>
<p>System independent sleep. This causes the current thread to sleep for
<em>usecs</em> microseconds.
<h3 class="fn">bool<a name="5dec86"></a>QThread::wait(unsignedlongtime=ULONG_MAX)</h3>
<p>This allows similar functionality to POSIX pthread_join. A thread
calling this will block until one of 2 conditions is met:
<ul>
<li> The thread associated with this QThread object has finished
execution (i.e. when it returns from <a href="#f1c9f8">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> <em>time</em> milliseconds has elapsed. If <em>time</em> is ULONG_MAX (default
argument), then the wait will never timeout (the thread must
return from run() ). This function will return FALSE
if the wait timed out.
</ul>
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