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The QThread class provides platform-independent threads. More...
All the functions in this class are thread-safe when Qt is built with thread support.
#include <qthread.h>
Inherits Qt.
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 run(). You inherit run() to include your code. For example:
class MyThread : public QThread { public: virtual void run(); }; void MyThread::run() { for( int count = 0; count < 20; count++ ) { sleep( 1 ); qDebug( "Ping!" ); } } int main() { MyThread a; MyThread b; a.start(); b.start(); a.wait(); b.wait(); }
This will start two threads, each of which writes Ping! 20 times to the screen and exits. The wait() 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().
See also Thread Support in Qt, Environment Classes, and Threading.
If stackSize is greater than zero, the maximum stack size is set to stackSize bytes, otherwise the maximum stack size is automatically determined by the operating system.
Warning: 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.
Note that deleting a QThread object will not stop the execution of the thread it represents. Deleting a running QThread (i.e. finished() returns FALSE) will probably result in a program crash. You can wait() on a thread to make sure that it has finished.
Warning: The handle returned by this function is used for internal purposes and should not 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.
Use QApplication::postEvent() instead.
This method is pure virtual, and must be implemented in derived classes in order to do useful work. Returning from this method will end the execution of the thread.
See also wait().
When the thread is terminated, all threads waiting for the the thread to finish will be woken up.
Warning: This function is dangerous, and its use is discouraged. The thread can be terminate at any point in its code path. Threads can be terminated while modifying data. There is no chance for the thread to cleanup after itself, unlock any held mutexes, etc. In short, use this function only if absolutely necessary.
This file is part of the Qt toolkit. Copyright © 1995-2003 Trolltech. All Rights Reserved.
Copyright © 2003 Trolltech | Trademarks | Qt version 3.1.2
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