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The QEventLoop class manages the event queue. More...
#include <qeventloop.h>
Inherits QObject.
It receives events from the window system and other sources. It then sends them to QApplication for prcoessing and delivery.
QEventLoop allows the application programmer to have more control over event delivery. Programs that perform long operations can call either processOneEvent() or processEvents() with various ProcessEvent values OR'ed together to control which events should be delivered.
QEventLoop also allows the integration of an external event loop with the Qt event loop. The Motif Extension included with Qt includes a reimplementation of QEventLoop for merging Qt and Motif events together.
See also Main Window and Related Classes and Event Classes.
This enum controls the types of events processed by the processEvents() functions.
See also processEvents().
See also ProcessEvents.
This signal is emitted before the event loop calls a function that could block.
See also awake().
Activates all pending socket notifiers and returns the number of socket notifiers that were activated.
Activates all Qt timers and returns the number of timers that were activated.
QEventLoop subclasses that do their own timer handling need to call this after the time returned by timeToWait() has elapsed.
This signal is emitted after the event loop returns from a function that could block.
See also wakeUp() and aboutToBlock().
This function enters the main event loop (recursively). Do not call it unless you really know what you are doing.
It is necessary to call this function to start event handling. The main event loop receives events from the window system and dispatches these to the application widgets.
Generally speaking, no user interaction can take place before calling exec(). As a special case, modal widgets like QMessageBox can be used before calling exec(), because modal widgets call exec() to start a local event loop.
To make your application perform idle processing, i.e. executing a special function whenever there are no pending events, use a QTimer with 0 timeout. More advanced idle processing schemes can be achieved using processEvents().
See also QApplication::quit(), exit(), and processEvents().
Tells the event loop to exit with a return code.
After this function has been called, the event loop returns from the call to exec(). The exec() function returns retcode.
By convention, a retcode of 0 means success, and any non-zero value indicates an error.
Note that unlike the C library function of the same name, this function does return to the caller -- it is event processing that stops.
See also QApplication::quit() and exec().
This function exits from a recursive call to the main event loop. Do not call it unless you really know what you are doing.
Returns TRUE if there is an event waiting, otherwise it returns FALSE.
Returns the current loop level.
This function is especially useful if you have a long running operation and want to show its progress without allowing user input, i.e. by using the ExcludeUserInput flag.
NOTE: Specifying the WaitForMore flag makes no sense, and will be ignored.
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Processes pending events that match flags. If no events matching flags are available, this function will wait for the next event if the WaitForMore flag is set in flags, otherwise it returns immediately.
Returns TRUE if an event was processed; otherwise returns FALSE.
See also ProcessEvents.
Registers notifier with the event loop. Subclasses need to reimplement this method to tie a socket notifier into another event loop. Reimplementations MUST call the base implementation.
Marks notifier as pending. The socket notifier will be activated the next time activateSocketNotifiers() is called.
Returns the number of milliseconds that Qt needs to handle its timers or -1 if there are no timers running.
QEventLoop subclasses that do their own timer handling need to use this to make sure that Qt's timers continue to work.
Unregisters notifier from the event loop. Subclasses need to reimplement this method to tie a socket notifier into another event loop. Reimplementations MUST call the base implementation.
Note: This function is thread-safe when Qt is built withthread support.
Wakes up the event loop.
See also awake().
This file is part of the Qt toolkit. Copyright © 1995-2002 Trolltech. All Rights Reserved.
Copyright © 2002 Trolltech | Trademarks | Qt version 3.1.0
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