From bd0f3345a938b35ce6a12f6150373b0955b8dd12 Mon Sep 17 00:00:00 2001 From: Timothy Pearson Date: Sun, 10 Jul 2011 15:24:15 -0500 Subject: Add Qt3 development HEAD version --- doc/html/qeventloop.html | 280 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 280 insertions(+) create mode 100644 doc/html/qeventloop.html (limited to 'doc/html/qeventloop.html') diff --git a/doc/html/qeventloop.html b/doc/html/qeventloop.html new file mode 100644 index 0000000..596c05a --- /dev/null +++ b/doc/html/qeventloop.html @@ -0,0 +1,280 @@ + + + + + +QEventLoop Class + + + + + + + +
+ +Home + | +All Classes + | +Main Classes + | +Annotated + | +Grouped Classes + | +Functions +

QEventLoop Class Reference

+ +

The QEventLoop class manages the event queue. +More... +

#include <qeventloop.h> +

Inherits QObject. +

Inherited by QMotif. +

List of all member functions. +

Public Members

+ +

Signals

+ +

Detailed Description

+ + +The QEventLoop class manages the event queue. +

+ +

It receives events from the window system and other sources. It +then sends them to QApplication for processing 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. +

To use your own instance of QEventLoop or QEventLoop subclass create +it before you create the QApplication object. +

See also Main Window and Related Classes and Event Classes. + +

Member Type Documentation

+

QEventLoop::ProcessEvents

+

This enum controls the types of events processed by the +processEvents() functions. +

See also processEvents(). + +

QEventLoop::ProcessEventsFlags

+A typedef to allow various ProcessEvents values to be OR'ed together. +

See also ProcessEvents. + +

Member Function Documentation

+

QEventLoop::QEventLoop ( QObject * parent = 0, const char * name = 0 ) +

+Creates a QEventLoop object, this object becomes the global event loop object. +There can only be one event loop object. The QEventLoop is usually constructed +by calling QApplication::eventLoop(). To create your own event loop object create +it before you instantiate the QApplication object. +

The parent and name arguments are passed on to the QObject constructor. + +

QEventLoop::~QEventLoop () +

+Destructs the QEventLoop object. + +

void QEventLoop::aboutToBlock () [signal] +

+

This signal is emitted before the event loop calls a function that +could block. +

See also awake(). + +

int QEventLoop::activateSocketNotifiers () +

+

Activates all pending socket notifiers and returns the number of +socket notifiers that were activated. + +

int QEventLoop::activateTimers () +

+

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. +

Note: This function is only useful on systems where select() is +used to block the eventloop. On Windows, this function always +returns 0. On MacOS X, this function always returns 0 when the +GUI is enabled. On MacOS X, this function returns the documented +value when the GUI is disabled. + +

void QEventLoop::awake () [signal] +

+

This signal is emitted after the event loop returns from a +function that could block. +

See also wakeUp() and aboutToBlock(). + +

int QEventLoop::enterLoop () [virtual] +

+

This function enters the main event loop (recursively). Do not call +it unless you really know what you are doing. + +

int QEventLoop::exec () [virtual] +

+Enters the main event loop and waits until exit() is called, and +returns the value that was set to exit(). +

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(). + +

void QEventLoop::exit ( int retcode = 0 ) [virtual] +

+

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(). + +

void QEventLoop::exitLoop () [virtual] +

+

This function exits from a recursive call to the main event loop. +Do not call it unless you really know what you are doing. + +

bool QEventLoop::hasPendingEvents () const [virtual] +

+

Returns TRUE if there is an event waiting, otherwise it returns FALSE. + +

int QEventLoop::loopLevel () const [virtual] +

+

Returns the current loop level. + +

void QEventLoop::processEvents ( ProcessEventsFlags flags, int maxTime ) +

+Process pending events that match flags for a maximum of maxTime milliseconds, or until there are no more events to +process, which ever is shorter. +

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: This function will not process events continuously; it +returns after all available events are processed. +

NOTE: Specifying the WaitForMore flag makes no sense and will +be ignored. + +

bool QEventLoop::processEvents ( ProcessEventsFlags flags ) [virtual] +

+ +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +

Processes pending events that match flags until there are no +more events to process. +

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. +

If the WaitForMore flag is set in flags, the behavior of +this function is as follows: +

+

If the WaitForMore flag is not set in flags, and no +events are available, this function will return immediately. +

NOTE: This function will not process events continuously; it +returns after all available events are processed. +

This function returns TRUE if an event was processed; otherwise it +returns FALSE. +

See also ProcessEvents and hasPendingEvents(). + +

void QEventLoop::registerSocketNotifier ( QSocketNotifier * notifier ) [virtual] +

+

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. + +

void QEventLoop::setSocketNotifierPending ( QSocketNotifier * notifier ) +

+

Marks notifier as pending. The socket notifier will be +activated the next time activateSocketNotifiers() is called. + +

int QEventLoop::timeToWait () const +

+

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. +

Note: This function is only useful on systems where select() is +used to block the eventloop. On Windows, this function always +returns -1. On MacOS X, this function always returns -1 when the +GUI is enabled. On MacOS X, this function returns the documented +value when the GUI is disabled. + +

void QEventLoop::unregisterSocketNotifier ( QSocketNotifier * notifier ) [virtual] +

+

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. + +

void QEventLoop::wakeUp () [virtual] +

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 © 1995-2007 +Trolltech. All Rights Reserved.

+ +
Copyright © 2007 +TrolltechTrademarks +
Qt 3.3.8
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