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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QThread Class Reference</h1>
<p>The QThread class provides platform-independent threads.
<a href="#details">More...</a>
<p><tt>#include <<a href="qthread-h.html">qthread.h</a>></tt>
<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="#QThread"><b>QThread</b></a> ()</div></li>
<li><div class=fn>virtual <a href="#~QThread"><b>~QThread</b></a> ()</div></li>
<li><div class=fn>bool <a href="#wait"><b>wait</b></a> ( unsigned long time = ULONG_MAX )</div></li>
<li><div class=fn>void <a href="#start"><b>start</b></a> ()</div></li>
<li><div class=fn>bool <a href="#finished"><b>finished</b></a> () const</div></li>
<li><div class=fn>bool <a href="#running"><b>running</b></a> () const</div></li>
</ul>
<h2>Static Public Members</h2>
<ul>
<li><div class=fn>Qt::HANDLE <a href="#currentThread"><b>currentThread</b></a> ()</div></li>
<li><div class=fn>void <a href="#postEvent"><b>postEvent</b></a> ( QObject * receiver, QEvent * event )</div></li>
<li><div class=fn>void <a href="#exit"><b>exit</b></a> ()</div></li>
</ul>
<h2>Protected Members</h2>
<ul>
<li><div class=fn>virtual void <a href="#run"><b>run</b></a> () = 0</div></li>
</ul>
<h2>Static Protected Members</h2>
<ul>
<li><div class=fn>void <a href="#sleep"><b>sleep</b></a> ( unsigned long secs )</div></li>
<li><div class=fn>void <a href="#msleep"><b>msleep</b></a> ( unsigned long msecs )</div></li>
<li><div class=fn>void <a href="#usleep"><b>usleep</b></a> ( unsigned long usecs )</div></li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The QThread class provides platform-independent threads.
<p>
<p> A QThread represents a separate thread of control within the program;
it shares data with all the 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(),
QThreads begin executing in <a href="#run">run</a>(). You inherit run()
to include your code. For example:
<p> <pre>
class MyThread : public QThread {
public:
virtual void run();
};
void MyThread::<a href="#run">run</a>()
{
for( int count = 0; count < 20; count++ ) {
<a href="#sleep">sleep</a>( 1 );
<a href="qapplication.html#qDebug">qDebug</a>( "Ping!" );
}
}
int main()
{
MyThread a;
MyThread b;
a.<a href="#start">start</a>();
b.<a href="#start">start</a>();
a.<a href="#wait">wait</a>();
b.<a href="#wait">wait</a>();
}
</pre>
<p> This will start two threads, each of which writes Ping! 20 times
to the screen and exits. The <a href="#wait">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> <p>See also <a href="threads.html">Thread Support in Qt</a>, <a href="environment.html">Environment Classes</a> and <a href="thread.html">Threading</a>.
<hr><h2>Member Function Documentation</h2>
<h3 class=fn><a name="QThread"></a>QThread::QThread ()
</h3>
Constructs a new thread. The thread does not actually begin executing
until <a href="#start">start</a>() is called.
<h3 class=fn><a name="~QThread"></a>QThread::~QThread ()<tt> [virtual]</tt>
</h3>
QThread destructor. Note that deleting a QThread object will not stop
the execution of the thread it represents. Deleting a running QThread
(ie. <a href="#finished">finished</a>() returns FALSE) will probably result in a program crash.
You can <a href="#wait">wait</a>() on the thread to make sure that the thread has finished.
<h3 class=fn>Qt::HANDLE <a name="currentThread"></a>QThread::currentThread ()<tt> [static]</tt>
</h3>
This returns the thread handle of the currently executing thread. The
handle returned by this function is used for internal reasons and
should <em>not</em> be used in any application code.
On Windows, the returned value is a pseudo handle for the current thread,
and it cannot be used for numerical comparison.
<h3 class=fn>void <a name="exit"></a>QThread::exit ()<tt> [static]</tt>
</h3>
Ends the execution of the calling thread and wakes up any threads waiting
for its termination.
<h3 class=fn>bool <a name="finished"></a>QThread::finished () const
</h3>
Returns TRUE is the thread is finished; otherwise returns FALSE.
<h3 class=fn>void <a name="msleep"></a>QThread::msleep ( unsigned long msecs )<tt> [static protected]</tt>
</h3>
System independent sleep. This causes the current thread to sleep for
<em>msecs</em> milliseconds
<h3 class=fn>void <a name="postEvent"></a>QThread::postEvent ( <a href="qobject.html">QObject</a> * receiver, <a href="qevent.html">QEvent</a> * event )<tt> [static]</tt>
</h3>
Provides a way of posting an event from a thread which is not the
event thread to an object. The <em>event</em> is put into a queue, then the
event thread is woken which then sends the event to the <em>receiver</em> 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
<a href="#postEvent">QThread::postEvent</a>().
<p> Since QThread::postEvent() posts events into the event queue of <a href="qapplication.html">QApplication</a>,
you must create a QApplication object before calling QThread::postEvent().
<p> The event must be allocated on the heap since the post event queue
will take ownership of the event and delete it once it has been posted.
<p> <p>See also <a href="qapplication.html#postEvent">QApplication::postEvent</a>().
<h3 class=fn>void <a name="run"></a>QThread::run ()<tt> [pure virtual protected]</tt>
</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.
<p> <p>See also <a href="#wait">wait</a>().
<h3 class=fn>bool <a name="running"></a>QThread::running () const
</h3>
Returns TRUE if the thread is running; otherwise returns FALSE.
<h3 class=fn>void <a name="sleep"></a>QThread::sleep ( unsigned long secs )<tt> [static protected]</tt>
</h3>
System independent sleep. This causes the current thread to sleep for
<em>secs</em> seconds.
<h3 class=fn>void <a name="start"></a>QThread::start ()
</h3>
This begins actual execution of the thread by calling <a href="#run">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="usleep"></a>QThread::usleep ( unsigned long usecs )<tt> [static protected]</tt>
</h3>
System independent sleep. This causes the current thread to sleep for
<em>usecs</em> microseconds
<h3 class=fn>bool <a name="wait"></a>QThread::wait ( unsigned long time = ULONG_MAX )
</h3>
This provides similar functionality to POSIX pthread_join. A thread
calling this will block until either of these conditions is met:
<ul>
<li> The thread associated with this QThread object has finished
execution (i.e. when it returns from <a href="#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> <em>time</em> milliseconds has elapsed. If <em>time</em> is ULONG_MAX (the
default), then the wait will never timeout (the thread must return
from <a href="#run">run</a>()). This function will return FALSE if the wait timed
out.
</ul>
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