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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">
<title>Qt Toolkit - QApplication Class</title><style type="text/css"><!--
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<a href="classes.html"><b>Classes</b></a>
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- <a href="hierarchy.html">Tree</a>
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<h1 align=center>QApplication Class Reference</h1><br clear="all">
<p>
The QApplication class manages the GUI application's control flow and main settings.
<a href="#details">More...</a>
<p>
<code>#include <<a href="qapplication-h.html">qapplication.h</a>></code>
<p>
Inherits <a href="qobject.html">QObject</a>.
<p>Inherited by <a href="qxtapplication.html">QXtApplication</a>.
<p><a href="qapplication-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li><div class="fn"><a href="#b8d5f2"><b>QApplication</b></a>(int&argc, char**argv)</div>
<li><div class="fn"><a href="#7bcefc"><b>QApplication</b></a>(int&argc, char**argv, boolGUIenabled)</div>
<li><div class="fn">enum<b>Type</b>{Tty, GuiClient, GuiServer}</div>
<li><div class="fn"><a href="#813297"><b>QApplication</b></a>(int&argc, char**argv, Type)</div>
<li><div class="fn">virtual<a href="#8cdd4f"><b>~QApplication</b></a>()</div>
<li><div class="fn">int<a href="#7bb8c9"><b>argc</b></a>()const</div>
<li><div class="fn">char**<a href="#c35457"><b>argv</b></a>()const</div>
<li><div class="fn">Type<b>type</b>()const</div>
<li><div class="fn">enum<b>ColorSpec</b>{NormalColor=0, CustomColor=1, ManyColor=2}</div>
<li><div class="fn">QWidget*<a href="#85380c"><b>mainWidget</b></a>()const</div>
<li><div class="fn">virtualvoid<a href="#7ad759"><b>setMainWidget</b></a>(QWidget*)</div>
<li><div class="fn">virtualvoid<a href="#11f8c4"><b>polish</b></a>(QWidget*)</div>
<li><div class="fn">QWidget*<a href="#df8f4c"><b>focusWidget</b></a>()const</div>
<li><div class="fn">QWidget*<a href="#aee839"><b>activeWindow</b></a>()const</div>
<li><div class="fn">int<a href="#84c7bf"><b>exec</b></a>()</div>
<li><div class="fn">void<a href="#30e70c"><b>processEvents</b></a>()</div>
<li><div class="fn">void<a href="#003456"><b>processEvents</b></a>(intmaxtime)</div>
<li><div class="fn">void<a href="#9f5779"><b>processOneEvent</b></a>()</div>
<li><div class="fn">int<a href="#c738a9"><b>enter_loop</b></a>()</div>
<li><div class="fn">void<a href="#90190e"><b>exit_loop</b></a>()</div>
<li><div class="fn">int<a href="#0454c7"><b>loopLevel</b></a>()const</div>
<li><div class="fn">virtualbool<a href="#80dc5b"><b>notify</b></a>(QObject*, QEvent*)</div>
<li><div class="fn">void<a href="#69de52"><b>setDefaultCodec</b></a>(QTextCodec*)</div>
<li><div class="fn">QTextCodec*<a href="#efe442"><b>defaultCodec</b></a>()const</div>
<li><div class="fn">void<a href="#e8df5e"><b>installTranslator</b></a>(QTranslator*)</div>
<li><div class="fn">void<a href="#8e6099"><b>removeTranslator</b></a>(QTranslator*)</div>
<li><div class="fn">QStringtranslate(constchar*, constchar*)const<em>(obsolete)</em></div>
<li><div class="fn">QString<a href="#35f6de"><b>translate</b></a>(constchar*, constchar*, constchar*)const</div>
<li><div class="fn">bool<a href="#aa8893"><b>isSessionRestored</b></a>()const</div>
<li><div class="fn">QString<a href="#a6fd61"><b>sessionId</b></a>()const</div>
<li><div class="fn">virtualvoid<a href="#6163c1"><b>commitData</b></a>(QSessionManager&sm)</div>
<li><div class="fn">virtualvoid<a href="#437e1b"><b>saveState</b></a>(QSessionManager&sm)</div>
<li><div class="fn">void<a href="#294481"><b>wakeUpGuiThread</b></a>()</div>
<li><div class="fn">void<a href="#e7d891"><b>lock</b></a>()</div>
<li><div class="fn">void<a href="#cc10ca"><b>unlock</b></a>(boolwakeUpGui=TRUE)</div>
<li><div class="fn">bool<a href="#8b7475"><b>locked</b></a>()</div>
</ul>
<h2>Public Slots</h2>
<ul>
<li><div class="fn">void<a href="#1af5b8"><b>quit</b></a>()</div>
<li><div class="fn">void<a href="#d8c05a"><b>closeAllWindows</b></a>()</div>
</ul>
<h2>Signals</h2>
<ul>
<li><div class="fn">void<a href="#4b242c"><b>lastWindowClosed</b></a>()</div>
<li><div class="fn">void<a href="#2ac1f2"><b>aboutToQuit</b></a>()</div>
<li><div class="fn">void<a href="#611442"><b>guiThreadAwake</b></a>()</div>
</ul>
<h2>Static Public Members</h2>
<ul>
<li><div class="fn">QStyle&<a href="#1bada8"><b>style</b></a>()</div>
<li><div class="fn">void<a href="#e52522"><b>setStyle</b></a>(QStyle*)</div>
<li><div class="fn">int<a href="#fdf8ca"><b>colorSpec</b></a>()</div>
<li><div class="fn">void<a href="#1ee2d1"><b>setColorSpec</b></a>(int)</div>
<li><div class="fn">QCursor*<a href="#d3b3f8"><b>overrideCursor</b></a>()</div>
<li><div class="fn">void<a href="#07e1f1"><b>setOverrideCursor</b></a>(constQCursor&, boolreplace=FALSE)</div>
<li><div class="fn">void<a href="#655095"><b>restoreOverrideCursor</b></a>()</div>
<li><div class="fn">bool<a href="#6029da"><b>hasGlobalMouseTracking</b></a>()</div>
<li><div class="fn">void<a href="#978595"><b>setGlobalMouseTracking</b></a>(boolenable)</div>
<li><div class="fn">QPalette<a href="#3e6f87"><b>palette</b></a>(constQWidget*=0)</div>
<li><div class="fn">void<a href="#63c60d"><b>setPalette</b></a>(constQPalette&, boolinformWidgets=FALSE, constchar*className=0)</div>
<li><div class="fn">QFont<a href="#f31495"><b>font</b></a>(constQWidget*=0)</div>
<li><div class="fn">void<a href="#3d926a"><b>setFont</b></a>(constQFont&, boolinformWidgets=FALSE, constchar*className=0)</div>
<li><div class="fn">QFontMetrics<a href="#9a9177"><b>fontMetrics</b></a>()</div>
<li><div class="fn">QWidgetList*<a href="#504f8c"><b>allWidgets</b></a>()</div>
<li><div class="fn">QWidgetList*<a href="#7b4eb5"><b>topLevelWidgets</b></a>()</div>
<li><div class="fn">QWidget*<a href="#d8ed8c"><b>desktop</b></a>()</div>
<li><div class="fn">QWidget*<a href="#329044"><b>activePopupWidget</b></a>()</div>
<li><div class="fn">QWidget*<a href="#375d04"><b>activeModalWidget</b></a>()</div>
<li><div class="fn">QClipboard*<a href="#1c95b5"><b>clipboard</b></a>()</div>
<li><div class="fn">QWidget*<a href="#48ddf6"><b>widgetAt</b></a>(intx, inty, boolchild=FALSE)</div>
<li><div class="fn">QWidget*<a href="#bf71e7"><b>widgetAt</b></a>(constQPoint&, boolchild=FALSE)</div>
<li><div class="fn">void<a href="#7328f6"><b>exit</b></a>(intretcode=0)</div>
<li><div class="fn">bool<a href="#333290"><b>sendEvent</b></a>(QObject*receiver, QEvent*event)</div>
<li><div class="fn">void<a href="#96d77e"><b>postEvent</b></a>(QObject*receiver, QEvent*event)</div>
<li><div class="fn">void<a href="#74f9e5"><b>sendPostedEvents</b></a>(QObject*receiver, intevent_type)</div>
<li><div class="fn">void<a href="#505bef"><b>sendPostedEvents</b></a>()</div>
<li><div class="fn">void<a href="#eb96e5"><b>removePostedEvents</b></a>(QObject*receiver)</div>
<li><div class="fn">bool<a href="#a61363"><b>startingUp</b></a>()</div>
<li><div class="fn">bool<a href="#568523"><b>closingDown</b></a>()</div>
<li><div class="fn">void<a href="#0965b7"><b>flushX</b></a>()</div>
<li><div class="fn">void<a href="#9cd282"><b>syncX</b></a>()</div>
<li><div class="fn">void<a href="#1f7ef4"><b>beep</b></a>()</div>
<li><div class="fn">voidsetWinStyleHighlightColor(constQColor&)<em>(obsolete)</em></div>
<li><div class="fn">constQColor&winStyleHighlightColor()<em>(obsolete)</em></div>
<li><div class="fn">void<a href="#7c5fe9"><b>setDesktopSettingsAware</b></a>(bool)</div>
<li><div class="fn">bool<a href="#76d935"><b>desktopSettingsAware</b></a>()</div>
<li><div class="fn">void<a href="#483f12"><b>setCursorFlashTime</b></a>(int)</div>
<li><div class="fn">int<a href="#325137"><b>cursorFlashTime</b></a>()</div>
<li><div class="fn">void<a href="#315795"><b>setDoubleClickInterval</b></a>(int)</div>
<li><div class="fn">int<a href="#af6c44"><b>doubleClickInterval</b></a>()</div>
<li><div class="fn">void<a href="#ea8301"><b>setWheelScrollLines</b></a>(int)</div>
<li><div class="fn">int<a href="#ebd93c"><b>wheelScrollLines</b></a>()</div>
<li><div class="fn">void<a href="#1b73fb"><b>setGlobalStrut</b></a>(constQSize&)</div>
<li><div class="fn">QSize<a href="#fcf1bf"><b>globalStrut</b></a>()</div>
<li><div class="fn">void<a href="#8f0390"><b>setStartDragTime</b></a>(intms)</div>
<li><div class="fn">int<a href="#66bdb0"><b>startDragTime</b></a>()</div>
<li><div class="fn">void<a href="#414075"><b>setStartDragDistance</b></a>(intl)</div>
<li><div class="fn">int<a href="#5a44a9"><b>startDragDistance</b></a>()</div>
<li><div class="fn">bool<a href="#6d0b7b"><b>isEffectEnabled</b></a>(Qt::UIEffect)</div>
<li><div class="fn">void<a href="#f40e3e"><b>setEffectEnabled</b></a>(Qt::UIEffect, boolenable=TRUE)</div>
</ul>
<h2>Related Functions</h2>
(Note that these are not member functions.)
<ul>
<li>void <a href="qapplication.html#0e1d68"><b>qFatal</b></a> (const char * msg, ...)
<li>void <a href="qapplication.html#290ef4"><b>qWarning</b></a> (const char * msg, ...)
<li>const char * <a href="qapplication.html#59b07d"><b>qVersion</b></a> ()
<li>void <a href="qapplication.html#6382b3"><b>qAddPostRoutine</b></a> (Q_CleanUpFunction p)
<li>void <a href="qapplication.html#6c7a8c"><b>ASSERT</b></a> (bool test)
<li>void <a href="qapplication.html#72e78c"><b>qDebug</b></a> (const char * msg, ...)
<li>bool <a href="qapplication.html#7e6130"><b>qSysInfo</b></a> (int * wordSize, bool * bigEndian)
<li>void <a href="qapplication.html#7ed4c6"><b>CHECK_PTR</b></a> (void * p)
<li>msg_handler <a href="qapplication.html#a8a31b"><b>qInstallMsgHandler</b></a> (msg_handler h)
</ul>
<hr><h2><a name="details"></a>Detailed Description</h2>
The QApplication class manages the GUI application's control flow and main settings.
<p>
It contains the main event loop, where all events from the window
system and other sources are processed and dispatched. It also
handles the application initialization and finalization, and
provides session management. Finally, it handles most system-wide
and application-wide settings.
<p>For any GUI application that uses Qt, there is precisely one
QApplication object, no matter whether the application has 0, 1, 2
or even more windows at the moment.
<p>This object (you can access is using the global variable <code>qApp)</code>
does a great many things, most importantly: <ul>
<li> It initializes the application to the user's desktop settings
like <a href="#3e6f87">palette</a>(), <a href="#f31495">font</a>() or the <a href="#af6c44">doubleClickInterval</a>(). It keeps track
of these properties in case the user changes the desktop globally
in some kind of control panel.
<li> It performs event handling, meaning that it receives events
from the underlying window system and sends them to the destination
widgets. By using <a href="#333290">sendEvent</a>() and <a href="#96d77e">postEvent</a>() you can send your own
events to widgets.
<li> It parses common command line arguments and sets its internal
state accordingly. See the constructor documentation below for more
details about this.
<li> It defines the application's look and feel, which is
encapsulated in a <a href="qstyle.html">QStyle</a> object. This can be changed during runtime
with <a href="#e52522">setStyle</a>().
<li> It specifies how the application is to allocate colors.
See <a href="#1ee2d1">setColorSpec</a>() for details.
<li> It specifies the default text encoding (see <a href="#69de52">setDefaultCodec</a>() )
and provides localization of strings that are visible to the user via
<a href="#35f6de">translate</a>().
<li> It provides some magic objects like the <a href="#d8ed8c">desktop</a>() and the
<a href="#1c95b5">clipboard</a>().
<li> It knows about the application's windows, and lets you ask
which widget is at a certain position using <a href="#48ddf6">widgetAt</a>(), lets you
<a href="#d8c05a">closeAllWindows</a>(), gives you a list of <a href="#7b4eb5">topLevelWidgets</a>(), etc.
<li> It manages the application's mouse cursor handling,
see <a href="#07e1f1">setOverrideCursor</a>() and <a href="#978595">setGlobalMouseTracking</a>().
<li> On the X window system, it provides functions to flush and sync
the communication stream, see <a href="#0965b7">flushX</a>() and <a href="#9cd282">syncX</a>().
<li> It provides support to implement sophisticated <a href="session.html">session management</a>. This makes it possible
for applications to terminate gracefully when the user logs out, to
cancel a shutdown process if termination isn't possible and even to
preserve the entire application state for a future session. See
<a href="#aa8893">isSessionRestored</a>(), <a href="#a6fd61">sessionId</a>() and <a href="#6163c1">commitData</a>() and <a href="#437e1b">saveState</a>()
for details.
<p></ul>
<p>The <a href="simple-application.html">Application walk-through
example</a> contains a typical complete main() that does the usual
things with QApplication.
<p>Since the QApplication object does so much initialization, it is
absolutely necessary to create it before any other objects related
to the user interface are created.
<p>Since it also deals with common command line arguments, it is
usually a good idea to create it <em>before</em> any interpretation or
modification of <code>argv</code> is done in the application itself. (Note
also that for X11, <a href="#7ad759">setMainWidget</a>() may change the main widget
according to the <code>-geometry</code> option. To preserve this
functionality, you must set your defaults before setMainWidget() and
any overrides after.)
<p><strong>Groups of functions:</strong>
<ul>
<li> System settings:
<a href="#76d935">desktopSettingsAware</a>(),
<a href="#7c5fe9">setDesktopSettingsAware</a>(),
<a href="#325137">cursorFlashTime</a>(),
<a href="#483f12">setCursorFlashTime</a>(),
doubleClickInterval(),
<a href="#315795">setDoubleClickInterval</a>(),
<a href="#ebd93c">wheelScrollLines</a>(),
<a href="#ea8301">setWheelScrollLines</a>(),
palette(),
<a href="#63c60d">setPalette</a>(),
font(),
<a href="#3d926a">setFont</a>(),
<a href="#9a9177">fontMetrics</a>().
<li> Event handling:
<a href="#84c7bf">exec</a>(),
<a href="#003456">processEvents</a>(),
<a href="#9f5779">processOneEvent</a>(),
<a href="#c738a9">enter_loop</a>(),
<a href="#90190e">exit_loop</a>(),
<a href="#7328f6">exit</a>(),
<a href="#1af5b8">quit</a>().
sendEvent(),
postEvent(),
<a href="#505bef">sendPostedEvents</a>(),
<a href="#eb96e5">removePostedEvents</a>(),
<a href="#80dc5b">notify</a>(),
<a href="#76e5c1">x11EventFilter</a>(),
<a href="#f6dcaf">x11ProcessEvent</a>(),
winEventFilter().
<li> GUI Styles:
<a href="#1bada8">style</a>(),
setStyle(),
<a href="#11f8c4">polish</a>().
<li> Color usage:
<a href="#fdf8ca">colorSpec</a>(),
setColorSpec().
<li> Text handling:
setDefaultCodec(),
<a href="#e8df5e">installTranslator</a>(),
<a href="#8e6099">removeTranslator</a>()
translate().
<li> Certain widgets:
<a href="#85380c">mainWidget</a>(),
setMainWidget(),
<a href="#504f8c">allWidgets</a>(),
topLevelWidgets(),
desktop(),
<a href="#329044">activePopupWidget</a>(),
<a href="#375d04">activeModalWidget</a>(),
clipboard(),
<a href="#df8f4c">focusWidget</a>(),
<a href="#aee839">activeWindow</a>(),
widgetAt().
<li> Advanced cursor handling:
<a href="#6029da">hasGlobalMouseTracking</a>(),
setGlobalMouseTracking(),
<a href="#d3b3f8">overrideCursor</a>(),
setOverrideCursor(),
<a href="#655095">restoreOverrideCursor</a>().
<li> X Window System synchronization:
flushX(),
syncX().
<li> Session management:
isSessionRestored(),
sessionId(),
commitData(),
saveState()
<li> Misc:
closeAllWindows(),
<a href="#a61363">startingUp</a>(),
<a href="#568523">closingDown</a>(),
</ul>
<p><strong>Non-GUI programs</strong><br> While Qt is not optimized or
designed for writing non-GUI programs, it's possible to use <a
href="tools.html">some of its classes</a> without creating a
QApplication. This can be useful if you wish to share code between
a non-GUI server and a GUI client.
<p>Examples:
<a href="showimg-main-cpp.html#QApplication">showimg/main.cpp</a>
<a href="action-main-cpp.html#QApplication">action/main.cpp</a>
<a href="rangecontrols-main-cpp.html#QApplication">rangecontrols/main.cpp</a>
<a href="iconview-main-cpp.html#QApplication">iconview/main.cpp</a>
<a href="validator-main-cpp.html#QApplication">validator/main.cpp</a>
<a href="themes-main-cpp.html#QApplication">themes/main.cpp</a>
<a href="listviews-main-cpp.html#QApplication">listviews/main.cpp</a>
<a href="aclock-main-cpp.html#QApplication">aclock/main.cpp</a>
<a href="checklists-main-cpp.html#QApplication">checklists/main.cpp</a>
<a href="drawlines-connect-cpp.html#QApplication">drawlines/connect.cpp</a>
<a href="dclock-main-cpp.html#QApplication">dclock/main.cpp</a>
<a href="wizard-main-cpp.html#QApplication">wizard/main.cpp</a>
<a href="xform-xform-cpp.html#QApplication">xform/xform.cpp</a>
<a href="application-main-cpp.html#QApplication">application/main.cpp</a>
<a href="cursor-cursor-cpp.html#QApplication">cursor/cursor.cpp</a>
<a href="layout-layout-cpp.html#QApplication">layout/layout.cpp</a>
<a href="helpviewer-main-cpp.html#QApplication">helpviewer/main.cpp</a>
<a href="buttongroups-main-cpp.html#QApplication">buttongroups/main.cpp</a>
<a href="life-main-cpp.html#QApplication">life/main.cpp</a>
<a href="i18n-main-cpp.html#QApplication">i18n/main.cpp</a>
<a href="drawdemo-drawdemo-cpp.html#QApplication">drawdemo/drawdemo.cpp</a>
<a href="lineedits-main-cpp.html#QApplication">lineedits/main.cpp</a>
<a href="popup-popup-cpp.html#QApplication">popup/popup.cpp</a>
<a href="fileiconview-main-cpp.html#QApplication">fileiconview/main.cpp</a>
<a href="listbox-main-cpp.html#QApplication">listbox/main.cpp</a>
<a href="menu-menu-cpp.html#QApplication">menu/menu.cpp</a>
<a href="progress-progress-cpp.html#QApplication">progress/progress.cpp</a>
<a href="scribble-main-cpp.html#QApplication">scribble/main.cpp</a>
<a href="qmag-qmag-cpp.html#QApplication">qmag/qmag.cpp</a>
<a href="tabdialog-main-cpp.html#QApplication">tabdialog/main.cpp</a>
<a href="splitter-splitter-cpp.html#QApplication">splitter/splitter.cpp</a>
<a href="progressbar-main-cpp.html#QApplication">progressbar/main.cpp</a>
<a href="tooltip-main-cpp.html#QApplication">tooltip/main.cpp</a>
<a href="richtext-main-cpp.html#QApplication">richtext/main.cpp</a>
<a href="qwerty-main-cpp.html#QApplication">qwerty/main.cpp</a>
<a href="forever-forever-cpp.html#QApplication">forever/forever.cpp</a>
<a href="rot13-rot13-cpp.html#QApplication">rot13/rot13.cpp</a>
<a href="xml-tagreader-with-features-tagreader-cpp.html#QApplication">xml/tagreader-with-features/tagreader.cpp</a>
<a href="desktop-desktop-cpp.html#QApplication">desktop/desktop.cpp</a>
<a href="scrollview-scrollview-cpp.html#QApplication">scrollview/scrollview.cpp</a>
<a href="qfd-qfd-cpp.html#QApplication">qfd/qfd.cpp</a>
<a href="addressbook-main-cpp.html#QApplication">addressbook/main.cpp</a>
<a href="movies-main-cpp.html#QApplication">movies/main.cpp</a>
<a href="picture-picture-cpp.html#QApplication">picture/picture.cpp</a>
<a href="hello-main-cpp.html#QApplication">hello/main.cpp</a>
<a href="listboxcombo-main-cpp.html#QApplication">listboxcombo/main.cpp</a>
<a href="biff-main-cpp.html#QApplication">biff/main.cpp</a>
<a href="tictac-main-cpp.html#QApplication">tictac/main.cpp</a>
<a href="customlayout-main-cpp.html#QApplication">customlayout/main.cpp</a>
<a href="mdi-main-cpp.html#QApplication">mdi/main.cpp</a>
<a href="dirview-main-cpp.html#QApplication">dirview/main.cpp</a>
<hr><h2>Member Function Documentation</h2>
<h3 class="fn"><a name="b8d5f2"></a>QApplication::QApplication(int&argc, char**argv)</h3>
<p>Initializes the window system and constructs an application object
with the command line arguments <em>argc</em> and <em>argv.</em>
<p>The global <code>qApp</code> pointer refers to this application object. Only
one application object should be created.
<p>This application object must be constructed before any <a href="qpaintdevice.html">paint devices</a> (includes widgets, pixmaps, bitmaps
etc.)
<p>Notice that <em>argc</em> and <em>argv</em> might be changed. Qt removes command
line arguments that it recognizes. The original <em>argc</em> and <em>argv</em>
are can be accessed later by <code>qApp-><a href="#7bb8c9">argc</a>()</code> and <code>qApp-><a href="#c35457">argv</a>().</code>
The documentation for argv() contains a detailed description of how
to process command line arguments.
<p>Qt debugging options (not available if Qt was compiled with the
NO_DEBUG flag defined):
<ul>
<li> <code>-nograb,</code> tells Qt to never grab the mouse or the keyboard.
<li> <code>-dograb</code> (only under X11), running under a debugger can cause
an implicit -nograb, use -dograb to override.
<li> <code>-sync</code> (only under X11), switches to synchronous mode for
debugging.
</ul>
<p>See <a href="debug.html">Debugging Techniques</a> for a more
detailed explanation.
<p>All Qt programs automatically support the following command line options:
<ul>
<li> <code>-style=</code> <em>style,</em> sets the application GUI style. Possible values
are <code>motif, windows,</code> and <code>platinum.</code>
<li> <code>-session=</code> <em>session,</em> restores the application from an earlier
<a href="session.html">session</a>.
</ul>
<p>The X11 version of Qt also supports some traditional X11
command line options:
<ul>
<li> <code>-display</code> <em>display,</em> sets the X display (default is $DISPLAY).
<li> <code>-geometry</code> <em>geometry,</em> sets the client geometry of the
<a href="#7ad759">main widget</a>.
<li> <code>-fn</code> or <code>-font</code> <em>font,</em> defines the application font.
<li> <code>-bg</code> or <code>-background</code> <em>color,</em> sets the default background color
and an application palette (light and dark shades are calculated).
<li> <code>-fg</code> or <code>-foreground</code> <em>color,</em> sets the default foreground color.
<li> <code>-btn</code> or <code>-button</code> <em>color,</em> sets the default button color.
<li> <code>-name</code> <em>name,</em> sets the application name.
<li> <code>-title</code> <em>title,</em> sets the application title (caption).
<li> <code>-visual TrueColor,</code> forces the application to use a TrueColor visual
on an 8-bit display.
<li> <code>-ncols</code> <em>count,</em> limits the number of colors allocated in the
color cube on a 8-bit display, if the application is using the
<code>QApplication::ManyColor</code> color specification. If <em>count</em> is
216 then a 6x6x6 color cube is used (ie. 6 levels of red, 6 of green,
and 6 of blue); for other values, a cube
approximately proportional to a 2x3x1 cube is used.
<li> <code>-cmap,</code> causes the application to install a private color map
on an 8-bit display.
</ul>
<p>See also <a href="#7bb8c9">argc</a>() and <a href="#c35457">argv</a>().
<h3 class="fn"><a name="813297"></a>QApplication::QApplication(int&argc, char**argv, Typetype)</h3>
<p>For Qt/Embedded, passing <em>QApplication::GuiServer</em> for <em>type</em>
make this application the server (equivalent to running with the
-qws option).
<h3 class="fn"><a name="7bcefc"></a>QApplication::QApplication(int&argc, char**argv, boolGUIenabled)</h3>
<p>Constructs an application object with the command line arguments <em>argc</em> and <em>argv.</em> If <em>GUIenabled</em> is TRUE, a normal application is
constructed, otherwise a non-GUI application is created.
<p>Set <em>GUIenabled</em> to FALSE for programs without a graphical user
interface that should be able to run without a window system.
<p>On X11, the window system is initialized if <em>GUIenabled</em> is TRUE.
If <em>GUIenabled</em> is FALSE, the application does not connect to the
X-server.
<p>On Windows, currently the window system is always initialized,
regardless of the value of GUIenabled. This may change in future
versions of Qt.
<p>The following example shows how to create an application that
uses a graphical interface when available.
<pre> int main( int argc, char **argv )
{
<a href="qapplication.html">QApplication</a> app(argc, argv, useGUI);
if ( useGUI ) {
//start GUI version
...
} else {
//start non-GUI version
...
}
return app.<a href="#84c7bf">exec</a>();
}
</pre>
<h3 class="fn"><a name="8cdd4f"></a>QApplication::~QApplication() <code>[virtual]</code></h3>
<p>Cleans up any window system resources that were allocated by this
application. Sets the global variable <code>qApp</code> to null.
<h3 class="fn">void<a name="2ac1f2"></a>QApplication::aboutToQuit() <code>[signal]</code></h3>
<p>This signal is emitted when the application is about to quit the
main event loop. This may happen either after a call to <a href="#1af5b8">quit</a>() from
inside the application or when the users shuts down the entire
desktop session.
<p>The signal is particularly useful if your application has to do some
last-second cleanups. Note that no user interaction is possible at
this state.
<p>See also <a href="#1af5b8">quit</a>().
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="375d04"></a>QApplication::activeModalWidget() <code>[static]</code></h3>
<p>Returns the active modal widget.
<p>A modal widget is a special top level widget which is a subclass of
<a href="qdialog.html">QDialog</a> that specifies the modal parameter of the constructor to
TRUE. A modal widget must be finished before the user can continue
with other parts of the program.
<p>The modal widgets are organized in a stack. This function returns
the active modal widget on top of the stack.
<p>See also <a href="#329044">activePopupWidget</a>() and <a href="#7b4eb5">topLevelWidgets</a>().
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="329044"></a>QApplication::activePopupWidget() <code>[static]</code></h3>
<p>Returns the active popup widget.
<p>A popup widget is a special top level widget that sets the <code>WType_Popup</code> widget flag, e.g. the <a href="qpopupmenu.html">QPopupMenu</a> widget. When the
application opens a popup widget, all events are sent to the popup.
Normal widgets and modal widgets cannot be accessed before the popup
widget is closed.
<p>Only other popup widgets may be opened when a popup widget is shown.
The popup widgets are organized in a stack. This function returns
the active popup widget on top of the stack.
<p>See also <a href="#375d04">activeModalWidget</a>() and <a href="#7b4eb5">topLevelWidgets</a>().
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="aee839"></a>QApplication::activeWindow()const</h3>
<p>Returns the application top-level window that has the keyboard input
focus, or null if no application window has the focus. Note that
there might be an activeWindow even if there is no <a href="#df8f4c">focusWidget</a>(),
for example if no widget in that window accepts key events.
<p>See also <a href="qwidget.html#25775a">QWidget::setFocus</a>(), <a href="qwidget.html#26f85d">QWidget::hasFocus</a>() and <a href="#df8f4c">focusWidget</a>().
<h3 class="fn">QWidgetList*<a name="504f8c"></a>QApplication::allWidgets() <code>[static]</code></h3>
<p>Returns a list of all the widgets in the application.
<p>The list is created using new and must be deleted by the caller.
<p>The list is empty (<a href="qlist.html#10b215">QList::isEmpty</a>()) if there are no widgets.
<p>Note that some of the widgets may be hidden.
<p>Example:
<pre> //
// Updates all widgets.
//
QWidgetList *list = QApplication::allWidgets();
QWidgetListIt it( *list ); // iterate over the widgets
<a href="qwidget.html">QWidget</a> * w;
while ( (w=it.current()) != 0 ) { // for each widget...
++it;
w-><a href="qwidget.html#a66a88">update</a>();
}
delete list; // delete the list, not the widgets
</pre>
<p>The QWidgetList class is defined in the qwidgetlist.h header file.<p><b>Warning:</b> Delete the list away as soon you have finished using it.
The widgets in the list may be deleted by someone else at any time.
<p>See also <a href="#7b4eb5">topLevelWidgets</a>(), <a href="qwidget.html#4d2aa7">QWidget::isVisible</a>() and <a href="qlist.html#10b215">QList::isEmpty</a>(),.
<h3 class="fn">int<a name="7bb8c9"></a>QApplication::argc()const</h3>
<p>Returns the number of command line arguments.
<p>The documentation for <a href="#c35457">argv</a>() contains a detailed description of how to
process command line arguments.
<p>See also <a href="#c35457">argv</a>() and <a href="#7bcefc">QApplication::QApplication</a>().
<h3 class="fn">char**<a name="c35457"></a>QApplication::argv()const</h3>
<p>Returns the command line argument vector.
<p><code>argv()[0]</code> is the program name, <code>argv()[1]</code> is the first argument and
<code>argv()[<a href="#7bb8c9">argc</a>()-1]</code> is the last argument.
<p>A QApplication object is constructed by passing <em>argc</em> and <em>argv</em>
from the <code>main()</code> function. Some of the arguments may be recognized
as Qt options removed from the argument vector. For example, the X11
version of Qt knows about <code>-display, -font</code> and a few more
options.
<p>Example:
<pre> // showargs.cpp - displays program arguments in a list box
#include <qapplication.h>
#include <qlistbox.h>
int main( int argc, char **argv )
{
<a href="qapplication.html">QApplication</a> a( argc, argv );
<a href="qlistbox.html">QListBox</a> b;
a.<a href="#7ad759">setMainWidget</a>( &b );
for ( int i=0; i<a.<a href="#7bb8c9">argc</a>(); i++ ) // a.<a href="#7bb8c9">argc</a>() == argc
b.<a href="qlistbox.html#04a671">insertItem</a>( a.<a href="#c35457">argv</a>()[i] ); // a.<a href="#c35457">argv</a>()[i] == argv[i]
b.<a href="qscrollview.html#45ec27">show</a>();
return a.<a href="#84c7bf">exec</a>();
}
</pre>
<p>If you run <tt>showargs -display unix:0 -font 9x15bold hello
world</tt> under X11, the list box contains the three strings
"showargs", "hello" and "world".
<p>See also <a href="#7bb8c9">argc</a>() and <a href="#7bcefc">QApplication::QApplication</a>().
<h3 class="fn">void<a name="1f7ef4"></a>QApplication::beep() <code>[static]</code></h3>
<p>Sounds the bell, using the default volume and sound.
<h3 class="fn"><a href="qclipboard.html">QClipboard</a>*<a name="1c95b5"></a>QApplication::clipboard() <code>[static]</code></h3>
<p>Returns a pointer to the application global clipboard.
<h3 class="fn">void<a name="d8c05a"></a>QApplication::closeAllWindows() <code>[slot]</code></h3>
<p>A convenience function that closes all toplevel windows.
<p>The function is particularly useful for applications with many
toplevel windows. It could for example be connected to a "Quit"
entry in the file menu as shown in the following code example:
<p><pre> // the "Quit" menu entry should try to close all windows
<a href="qpopupmenu.html">QPopupMenu</a>* file = new <a href="qpopupmenu.html">QPopupMenu</a>( this );
file-><a href="qmenudata.html#0076cb">insertItem</a>( tr("&Quit"), qApp, SLOT(closeAllWindows()), CTRL+Key_Q );
// when the last window was closed, the application should quit
connect( qApp, SIGNAL( lastWindowClosed() ), qApp, SLOT( quit() ) );
</pre>
<p>The windows are closed in random order, until one window does not
accept the close event.
<p>See also <a href="qwidget.html#3d9c87">QWidget::close</a>(), <a href="qwidget.html#c04094">QWidget::closeEvent</a>(), <a href="#4b242c">lastWindowClosed</a>(), <a href="#1af5b8">quit</a>(), <a href="#7b4eb5">topLevelWidgets</a>() and <a href="qwidget.html#17338a">QWidget::isTopLevel</a>().
<h3 class="fn">bool<a name="568523"></a>QApplication::closingDown() <code>[static]</code></h3>
<p>Returns TRUE if the application objects are being destroyed.
<p>See also <a href="#a61363">startingUp</a>().
<h3 class="fn">int<a name="fdf8ca"></a>QApplication::colorSpec() <code>[static]</code></h3>
<p>Returns the color specification.
<p>See also <a href="#1ee2d1">QApplication::setColorSpec</a>().
<h3 class="fn">void<a name="6163c1"></a>QApplication::commitData(<a href="qsessionmanager.html">QSessionManager</a>&sm) <code>[virtual]</code></h3>
<p>This function deals with session management. It is invoked when the
<a href="qsessionmanager.html">QSessionManager</a> wants the application to commit all its data.
<p>Usually this means saving of all open files, after getting
permission from the user. Furthermore you may want to provide the
user a way to cancel the shutdown.
<p>Note that you should not exit the application within this function.
Instead, the session manager may or may not do this afterwards,
depending on the context.
<p><strong>Important</strong><br> Within this function, no user
interaction is possible, <em>unless</em> you ask the session manager <em>sm</em>
for explicit permission. See <a href="qsessionmanager.html#25f903">QSessionManager::allowsInteraction</a>()
and <a href="qsessionmanager.html#8110b0">QSessionManager::allowsErrorInteraction</a>() for details and
example usage.
<p>The default implementation requests interaction and sends a close
event to all visible toplevel widgets. If at least one event was
rejected, the shutdown is cancelled.
<p>See also <a href="#aa8893">isSessionRestored</a>(), <a href="#a6fd61">sessionId</a>() and <a href="#437e1b">saveState</a>().
<h3 class="fn">int<a name="325137"></a>QApplication::cursorFlashTime() <code>[static]</code></h3>
<p>Returns the text cursor's flash time in milliseconds. The flash time
is the time required to display, invert and restore the caret
display.
<p>The default value on X11 is 1000 milliseconds. On Windows, the
control panel value is used.
<p>Widgets should not cache this value since it may vary any time the
user changes the global desktop settings.
<p>See also <a href="#483f12">setCursorFlashTime</a>().
<h3 class="fn"><a href="qtextcodec.html">QTextCodec</a>*<a name="efe442"></a>QApplication::defaultCodec()const</h3>
<p>Returns the default codec (see <a href="#69de52">setDefaultCodec</a>()).
Returns 0 by default (no codec).
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="d8ed8c"></a>QApplication::desktop() <code>[static]</code></h3>
<p>Returns the desktop widget (also called the root window).
<p>The desktop widget is useful for obtaining the size of the screen.
It may also be possible to draw on the desktop. We recommend against
assuming that it's possible to draw on the desktop, as it works on
some machines and not on others.
<p><pre> <a href="qwidget.html">QWidget</a> *d = QApplication::desktop();
int w=d-><a href="qwidget.html#2edab1">width</a>(); // returns screen width
int h=d-><a href="qwidget.html#e3c588">height</a>(); // returns screen height
</pre>
<p>Examples:
<a href="helpviewer-main-cpp.html#QApplication::desktop">helpviewer/main.cpp</a>
<a href="scribble-main-cpp.html#QApplication::desktop">scribble/main.cpp</a>
<a href="qmag-qmag-cpp.html#QApplication::desktop">qmag/qmag.cpp</a>
<h3 class="fn">bool<a name="76d935"></a>QApplication::desktopSettingsAware() <code>[static]</code></h3>
<p>Returns the value set by <a href="#7c5fe9">setDesktopSettingsAware</a>(), by default TRUE.
<p>See also <a href="#7c5fe9">setDesktopSettingsAware</a>().
<h3 class="fn">int<a name="af6c44"></a>QApplication::doubleClickInterval() <code>[static]</code></h3>
<p>Returns the maximum duration for a double click.
<p>The default value on X11 is 400 milliseconds. On Windows, the control
panel value is used.
<p>See also <a href="#315795">setDoubleClickInterval</a>().
<h3 class="fn">int<a name="c738a9"></a>QApplication::enter_loop()</h3>
<p>This function enters the main event loop (recursively). Do not call
it unless you really know what you are doing.
<p>See also <a href="#90190e">exit_loop</a>() and <a href="#0454c7">loopLevel</a>().
<h3 class="fn">int<a name="84c7bf"></a>QApplication::exec()</h3>
<p>Enters the main event loop and waits until <a href="#7328f6">exit</a>() is called or the
main widget is destroyed, and Returns the value that was set via to
exit() (which is 0 if exit() is called via <a href="#1af5b8">quit</a>()).
<p>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.
<p>Generally speaking, no user interaction can take place before
calling exec(). As a special case, modal widgets like <a href="qmessagebox.html">QMessageBox</a>
can be used before calling exec(), because modal widgets call exec()
to start a local event loop.
<p>To make your application perform idle processing, i.e. executing a
special function whenever there are no pending events, use a <a href="qtimer.html">QTimer</a>
with 0 timeout. More advanced idle processing schemes can be
achieved by using <a href="#003456">processEvents</a>() and <a href="#9f5779">processOneEvent</a>().
<p>See also <a href="#1af5b8">quit</a>(), <a href="#7328f6">exit</a>(), <a href="#003456">processEvents</a>() and <a href="#7ad759">setMainWidget</a>().
<p>Examples:
<a href="showimg-main-cpp.html#exec">showimg/main.cpp</a>
<a href="action-main-cpp.html#exec">action/main.cpp</a>
<a href="rangecontrols-main-cpp.html#exec">rangecontrols/main.cpp</a>
<a href="iconview-main-cpp.html#exec">iconview/main.cpp</a>
<a href="validator-main-cpp.html#exec">validator/main.cpp</a>
<a href="themes-main-cpp.html#exec">themes/main.cpp</a>
<a href="listviews-main-cpp.html#exec">listviews/main.cpp</a>
<a href="aclock-main-cpp.html#exec">aclock/main.cpp</a>
<a href="checklists-main-cpp.html#exec">checklists/main.cpp</a>
<a href="drawlines-connect-cpp.html#exec">drawlines/connect.cpp</a>
<a href="dclock-main-cpp.html#exec">dclock/main.cpp</a>
<a href="mainlyQt-editor-cpp.html#exec">mainlyQt/editor.cpp</a>
<a href="xform-xform-cpp.html#exec">xform/xform.cpp</a>
<a href="application-main-cpp.html#exec">application/main.cpp</a>
<a href="cursor-cursor-cpp.html#exec">cursor/cursor.cpp</a>
<a href="layout-layout-cpp.html#exec">layout/layout.cpp</a>
<a href="helpviewer-main-cpp.html#exec">helpviewer/main.cpp</a>
<a href="buttongroups-main-cpp.html#exec">buttongroups/main.cpp</a>
<a href="life-main-cpp.html#exec">life/main.cpp</a>
<a href="i18n-main-cpp.html#exec">i18n/main.cpp</a>
<a href="drawdemo-drawdemo-cpp.html#exec">drawdemo/drawdemo.cpp</a>
<a href="lineedits-main-cpp.html#exec">lineedits/main.cpp</a>
<a href="popup-popup-cpp.html#exec">popup/popup.cpp</a>
<a href="fileiconview-main-cpp.html#exec">fileiconview/main.cpp</a>
<a href="listbox-main-cpp.html#exec">listbox/main.cpp</a>
<a href="menu-menu-cpp.html#exec">menu/menu.cpp</a>
<a href="progress-progress-cpp.html#exec">progress/progress.cpp</a>
<a href="scribble-main-cpp.html#exec">scribble/main.cpp</a>
<a href="qmag-qmag-cpp.html#exec">qmag/qmag.cpp</a>
<a href="tabdialog-main-cpp.html#exec">tabdialog/main.cpp</a>
<a href="splitter-splitter-cpp.html#exec">splitter/splitter.cpp</a>
<a href="progressbar-main-cpp.html#exec">progressbar/main.cpp</a>
<a href="tooltip-main-cpp.html#exec">tooltip/main.cpp</a>
<a href="richtext-main-cpp.html#exec">richtext/main.cpp</a>
<a href="qwerty-main-cpp.html#exec">qwerty/main.cpp</a>
<a href="forever-forever-cpp.html#exec">forever/forever.cpp</a>
<a href="rot13-rot13-cpp.html#exec">rot13/rot13.cpp</a>
<a href="xml-tagreader-with-features-tagreader-cpp.html#exec">xml/tagreader-with-features/tagreader.cpp</a>
<a href="scrollview-scrollview-cpp.html#exec">scrollview/scrollview.cpp</a>
<a href="qfd-qfd-cpp.html#exec">qfd/qfd.cpp</a>
<a href="addressbook-main-cpp.html#exec">addressbook/main.cpp</a>
<a href="movies-main-cpp.html#exec">movies/main.cpp</a>
<a href="picture-picture-cpp.html#exec">picture/picture.cpp</a>
<a href="hello-main-cpp.html#exec">hello/main.cpp</a>
<a href="listboxcombo-main-cpp.html#exec">listboxcombo/main.cpp</a>
<a href="biff-main-cpp.html#exec">biff/main.cpp</a>
<a href="tictac-main-cpp.html#exec">tictac/main.cpp</a>
<a href="customlayout-main-cpp.html#exec">customlayout/main.cpp</a>
<a href="mdi-main-cpp.html#exec">mdi/main.cpp</a>
<a href="dirview-main-cpp.html#exec">dirview/main.cpp</a>
<h3 class="fn">void<a name="7328f6"></a>QApplication::exit(intretcode=0) <code>[static]</code></h3>
<p>Tells the application to exit with a return code.
<p>After this function has been called, the application leaves the main
event loop and returns from the call to <a href="#84c7bf">exec</a>(). The exec() function
returns <em>retcode.</em>
<p>By convention, <em>retcode</em> 0 means success, any non-zero value
indicates an error.
<p>Note that unlike the C library function of the same name, this
function <em>does</em> returns to the caller - it is event processing that
stops.
<p>See also <a href="#1af5b8">quit</a>() and <a href="#84c7bf">exec</a>().
<p>Examples:
<a href="picture-picture-cpp.html#QApplication::exit">picture/picture.cpp</a>
<h3 class="fn">void<a name="90190e"></a>QApplication::exit_loop()</h3>
<p>This function leaves from a recursive call to the main event loop.
Do not call it unless you are an expert.
<p>See also <a href="#c738a9">enter_loop</a>() and <a href="#0454c7">loopLevel</a>().
<h3 class="fn">void<a name="0965b7"></a>QApplication::flushX() <code>[static]</code></h3>
<p>Flushes the X event queue in the X11 implementation. This normally
returns almost immediately. Does nothing on other platforms.
<p>See also <a href="#9cd282">syncX</a>().
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="df8f4c"></a>QApplication::focusWidget()const</h3>
<p>Returns the application widget that has the keyboard input focus, or
null if no widget in this application has the focus.
<p>See also <a href="qwidget.html#25775a">QWidget::setFocus</a>(), <a href="qwidget.html#26f85d">QWidget::hasFocus</a>() and <a href="#aee839">activeWindow</a>().
<h3 class="fn"><a href="qfont.html">QFont</a><a name="f31495"></a>QApplication::font(const<a href="qwidget.html">QWidget</a>*w=0) <code>[static]</code></h3>
<p>Returns the default font for a widget. Basically this function uses
<a href="qobject.html#fa7716">w->className()</a> to get a font for it.
<p>If <em>w</em> is 0 the default application font is returned.
<p>See also <a href="#3d926a">setFont</a>(), <a href="#9a9177">fontMetrics</a>() and <a href="qwidget.html#167922">QWidget::font</a>().
<h3 class="fn"><a href="qfontmetrics.html">QFontMetrics</a><a name="9a9177"></a>QApplication::fontMetrics() <code>[static]</code></h3>
<p>Returns display (screen) font metrics for the application font.
<p>See also <a href="#f31495">font</a>(), <a href="#3d926a">setFont</a>(), <a href="qwidget.html#386569">QWidget::fontMetrics</a>() and <a href="qpainter.html#73b2e5">QPainter::fontMetrics</a>().
<h3 class="fn"><a href="qsize.html">QSize</a><a name="fcf1bf"></a>QApplication::globalStrut() <code>[static]</code></h3>
<p>Returns the global strut of the application.
<p>See also <a href="#1b73fb">setGlobalStrut</a>().
<h3 class="fn">void<a name="611442"></a>QApplication::guiThreadAwake() <code>[signal]</code></h3>
<p>This signal is emitted when the GUI threads is about to process a cycle
of the event loop.
<p>See also <a href="#294481">wakeUpGuiThread</a>().
<h3 class="fn">bool<a name="6029da"></a>QApplication::hasGlobalMouseTracking() <code>[static]</code></h3>
<p>Returns TRUE if global mouse tracking is enabled, otherwise FALSE.
<p>See also <a href="#978595">setGlobalMouseTracking</a>().
<h3 class="fn">void<a name="e8df5e"></a>QApplication::installTranslator(<a href="qtranslator.html">QTranslator</a>*mf)</h3>
<p>Adds <em>mf</em> to the list of message files to be used for
localization. Message files are searched starting with the most
recently added file.
<p>See also <a href="#8e6099">removeTranslator</a>(), <a href="#35f6de">translate</a>() and <a href="qobject.html#2418a9">QObject::tr</a>().
<h3 class="fn">bool<a name="6d0b7b"></a>QApplication::isEffectEnabled(Qt::UIEffecteffect) <code>[static]</code></h3>
<p>Returns TRUE if <em>effect</em> is enabled, otherwise FALSE.
<p>By default, Qt will try to use the desktop settings, and
<a href="#7c5fe9">setDesktopSettingsAware</a>() must be called to prevent this.
<p>sa\ <a href="#f40e3e">setEffectEnabled</a>(), Qt::UIEffect.
<h3 class="fn">bool<a name="aa8893"></a>QApplication::isSessionRestored()const</h3>
<p>Returns whether the application has been restored from an earlier
session.
<p>See also <a href="#a6fd61">sessionId</a>(), <a href="#6163c1">commitData</a>() and <a href="#437e1b">saveState</a>().
<h3 class="fn">void<a name="4b242c"></a>QApplication::lastWindowClosed() <code>[signal]</code></h3>
<p>This signal is emitted when the user has closed the last remaining
top level window.
<p>The signal is very useful when your application has many top level
widgets but no main widget. You can then connect it to the <a href="#1af5b8">quit</a>()
slot.
<p>For convenience, transient toplevel widgets such as popup menus and
dialogs are omitted.
<p>See also <a href="#85380c">mainWidget</a>(), <a href="#7b4eb5">topLevelWidgets</a>(), <a href="qwidget.html#17338a">QWidget::isTopLevel</a>() and <a href="qwidget.html#3d9c87">QWidget::close</a>().
<h3 class="fn">void<a name="e7d891"></a>QApplication::lock()</h3>
<p>Lock the Qt library mutex. If another thread has already locked the
mutex, the calling thread will block until the other thread has
unlocked the mutex.
<p>See also <a href="#cc10ca">unlock</a>() and <a href="#8b7475">locked</a>().
<h3 class="fn">bool<a name="8b7475"></a>QApplication::locked()</h3>
<p>Returns TRUE if the Qt library mutex is locked by a different thread,
otherwise returns FALSE.
<p><em>NOTE:</em> Due to differing implementations of recursive mutexes on various
platforms, calling this function from the same thread that previous locked
the mutex will return undefined results.
<p>See also <a href="#e7d891">lock</a>() and <a href="#cc10ca">unlock</a>().
<h3 class="fn">int<a name="0454c7"></a>QApplication::loopLevel()const</h3>
<p>Returns the current loop level
<p>See also <a href="#c738a9">enter_loop</a>() and <a href="#90190e">exit_loop</a>().
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="85380c"></a>QApplication::mainWidget()const</h3>
<p>Returns the main application widget, or a null pointer if there is
not a defined main widget.
<p>See also <a href="#7ad759">setMainWidget</a>().
<h3 class="fn">bool<a name="80dc5b"></a>QApplication::notify(<a href="qobject.html">QObject</a>*receiver, <a href="qevent.html">QEvent</a>*event) <code>[virtual]</code></h3>
<p>Sends <em>event</em> to <em>receiver:</em> <code>receiver-><a href="qobject.html#c67adb">event</a>( event )</code>
Returns the value that is returned from the receiver's event handler.
<p>Reimplementing this virtual function is one of five ways to process
an event: <ol> <li> Reimplementing this function. Very powerful,
you get <em>complete</em> control, but of course only one subclass can be
qApp.
<li> Installing an event filter on qApp. Such an event filter gets
to process all events for all widgets, so it's just as powerful as
reimplementing notify(), and in this way it's possible to have more
than one application-global event filter. Global event filter get
to see even mouse events for <a href="qwidget.html#f9af61">disabled
widgets,</a> and if <a href="#978595">global mouse
tracking</a> is enabled, mouse move events for all widgets.
<li> Reimplementing <a href="qobject.html#c67adb">QObject::event</a>() (as <a href="qwidget.html">QWidget</a> does). If you do
this you get tab key-presses, and you get to see the events before
any widget-specific event filters.
<li> Installing an event filter on the object. Such an even filter
gets all the events except Tab and Shift-Tab key presses.
<li> Finally, reimplementing paintEvent(), mousePressEvent() and so
on. This is the normal, easiest and least powerful way. </ol>
<p>See also <a href="qobject.html#c67adb">QObject::event</a>() and <a href="qobject.html#185219">installEventFilter</a>().
<h3 class="fn"><a href="qcursor.html">QCursor</a>*<a name="d3b3f8"></a>QApplication::overrideCursor() <code>[static]</code></h3>
<p>Returns the active application override cursor.
<p>This function returns 0 if no application cursor has been defined
(i.e. the internal cursor stack is empty).
<p>See also <a href="#07e1f1">setOverrideCursor</a>() and <a href="#655095">restoreOverrideCursor</a>().
<h3 class="fn"><a href="qpalette.html">QPalette</a><a name="3e6f87"></a>QApplication::palette(const<a href="qwidget.html">QWidget</a>*w=0) <code>[static]</code></h3>
<p>Returns a pointer to the default application palette. There is
always an application palette, i.e. the returned pointer is
guaranteed to be non-null.
<p>If a widget is passed as argument, the default palette for the
widget's class is returned. This may or may not be the application
palett. In most cases there isn't be a special palette for certain
types of widgets, but one notable exception is the popup menu under
Windows, if the user has defined a special background color for
menus in the display settings.
<p>See also <a href="#63c60d">setPalette</a>() and <a href="qwidget.html#370880">QWidget::palette</a>().
<h3 class="fn">void<a name="11f8c4"></a>QApplication::polish(<a href="qwidget.html">QWidget</a>*w) <code>[virtual]</code></h3>
<p>Polishing of widgets.
<p>Usually widgets call this automatically when they are polished. It
may be used to do some style-based central customization of widgets.
<p>Note that you are not limited to public functions of <a href="qwidget.html">QWidget</a>.
Instead, based on meta information like <a href="qobject.html#fa7716">QObject::className</a>() you are
able to customize any kind of widgets.
<p>See also <a href="qstyle.html#07b10b">QStyle::polish</a>(), <a href="qwidget.html#c14a09">QWidget::polish</a>(), <a href="#63c60d">setPalette</a>() and <a href="#3d926a">setFont</a>().
<h3 class="fn">void<a name="96d77e"></a>QApplication::postEvent(<a href="qobject.html">QObject</a>*receiver, <a href="qevent.html">QEvent</a>*event) <code>[static]</code></h3>
<p>Stores the event in a queue and returns immediately.
<p>The event must be allocated on the heap, as it is deleted when the event
has been posted.
<p>When control returns to the main event loop, all events that are
stored in the queue will be sent using the <a href="#80dc5b">notify</a>() function.
<p>See also <a href="#333290">sendEvent</a>().
<h3 class="fn">void<a name="30e70c"></a>QApplication::processEvents()</h3>
<p>Processes pending events, for 3 seconds or until there are no more
events to process, whichever is shorter.
<p>You can call this function occasionally when your program is busy
doing a long operation (e.g. copying a file).
<p>See also <a href="#9f5779">processOneEvent</a>(), <a href="#84c7bf">exec</a>() and <a href="qtimer.html">QTimer</a>.
<h3 class="fn">void<a name="003456"></a>QApplication::processEvents(intmaxtime)</h3>
<p>Processes pending events for <em>maxtime</em> milliseconds or until there
are no more events to process, whichever is shorter.
<p>You can call this function occasionally when you program is busy doing a
long operation (e.g. copying a file).
<p>See also <a href="#9f5779">processOneEvent</a>(), <a href="#84c7bf">exec</a>() and <a href="qtimer.html">QTimer</a>.
<h3 class="fn">void<a name="9f5779"></a>QApplication::processOneEvent()</h3>
<p>Waits for an event to occur, processes it, then returns.
<p>This function is useful for adapting Qt to situations where the
event processing must be grafted into existing program loops. Using
this function in new applications may be an indication of design
problems.
<p>See also <a href="#003456">processEvents</a>(), <a href="#84c7bf">exec</a>() and <a href="qtimer.html">QTimer</a>.
<h3 class="fn">void<a name="1af5b8"></a>QApplication::quit() <code>[slot]</code></h3>
<p>Tells the application to exit with return code 0 (success).
Equivalent to calling <a href="#7328f6">QApplication::exit</a>( 0 ).
<p>This function is a slot, so you may connect any signal to activate
quit().
<p>Example:
<pre> <a href="qpushbutton.html">QPushButton</a> *quitButton = new <a href="qpushbutton.html">QPushButton</a>( "Quit" );
connect( quitButton, SIGNAL(clicked()), qApp, SLOT(quit()) );
</pre>
<p>See also <a href="#7328f6">exit</a>() and <a href="#2ac1f2">aboutToQuit</a>().
<h3 class="fn">void<a name="eb96e5"></a>QApplication::removePostedEvents(<a href="qobject.html">QObject</a>*receiver) <code>[static]</code></h3>
<p>Removes all events posted using <a href="#96d77e">postEvent</a>() for <em>receiver.</em>
<p>The events are <em>not</em> dispatched, simply removed from the queue. You
should never need to call this function. If you do call it, be aware
that killing events may cause <em>receiver</em> to break one or more
invariants.
<h3 class="fn">void<a name="8e6099"></a>QApplication::removeTranslator(<a href="qtranslator.html">QTranslator</a>*mf)</h3>
<p>Removes <em>mf</em> from the list of message files used by this
application. Does not, of course, delete mf.
<p>See also <a href="#e8df5e">installTranslator</a>(), <a href="#35f6de">translate</a>() and <a href="qobject.html#2418a9">QObject::tr</a>().
<h3 class="fn">void<a name="655095"></a>QApplication::restoreOverrideCursor() <code>[static]</code></h3>
<p>Undoes the last <a href="#07e1f1">setOverrideCursor</a>().
<p>If setOverrideCursor() has been called twice, calling
restoreOverrideCursor() will activate the first cursor set. Calling
this function a second time restores the original widgets cursors.
<p>See also <a href="#07e1f1">setOverrideCursor</a>() and <a href="#d3b3f8">overrideCursor</a>().
<h3 class="fn">void<a name="437e1b"></a>QApplication::saveState(<a href="qsessionmanager.html">QSessionManager</a>&sm) <code>[virtual]</code></h3>
<p>This function deals with session management. It is invoked when the
<a href="qsessionmanager.html">session manager</a> wants the application
to preserve its state for a future session.
<p>For a text editor this would mean creating a temporary file that
includes the current contents of the edit buffers, the location of
the cursor and other aspects of the current editing session.
<p>Note that you should never exit the application within this
function. Instead, the session manager may or may not do this
afterwards, depending on the context. Futhermore, most session
managers will very likely request a saved state immediately after
the application has been started. This permits the session manager
to learn about the application's restart policy.
<p><strong>Important</strong><br> Within this function, no user
interaction is possible, <em>unless</em> you ask the session manager <em>sm</em>
for explicit permission. See <a href="qsessionmanager.html#25f903">QSessionManager::allowsInteraction</a>()
and <a href="qsessionmanager.html#8110b0">QSessionManager::allowsErrorInteraction</a>() for details.
<p>See also <a href="#aa8893">isSessionRestored</a>(), <a href="#a6fd61">sessionId</a>() and <a href="#6163c1">commitData</a>().
<h3 class="fn">bool<a name="333290"></a>QApplication::sendEvent(<a href="qobject.html">QObject</a>*receiver, <a href="qevent.html">QEvent</a>*event) <code>[static]</code></h3>
<p>Sends an event directly to a receiver, using the <a href="#80dc5b">notify</a>() function.
Returns the value that was returned from the event handler.
<p>See also <a href="#96d77e">postEvent</a>() and <a href="#80dc5b">notify</a>().
<p>Examples:
<a href="popup-popup-cpp.html#QApplication::sendEvent">popup/popup.cpp</a>
<h3 class="fn">void<a name="505bef"></a>QApplication::sendPostedEvents() <code>[static]</code></h3>
<p>Dispatches all posted events.
<h3 class="fn">void<a name="74f9e5"></a>QApplication::sendPostedEvents(<a href="qobject.html">QObject</a>*receiver, intevent_type) <code>[static]</code></h3>
<p>Immediately dispatches all events which have been previously enqueued
with <a href="#96d77e">QApplication::postEvent</a>() and which are for the object <em>receiver</em>
and have the <em>event_type.</em>
<p>Some event compression may occur. Note that events from the window
system are <em>not</em> dispatched by this function.
<h3 class="fn"><a href="qstring.html">QString</a><a name="a6fd61"></a>QApplication::sessionId()const</h3>
<p>Returns the identifier of the current session.
<p>If the application has been restored from an earlier session, this
identifier is the same as it was in that previous session.
<p>The session identifier is guaranteed to be unique for both different
applications and different instances of the same application.
<p>See also <a href="#aa8893">isSessionRestored</a>(), <a href="#6163c1">commitData</a>() and <a href="#437e1b">saveState</a>().
<h3 class="fn">void<a name="1ee2d1"></a>QApplication::setColorSpec(intspec) <code>[static]</code></h3>
<p>Sets the color specification for the application to <em>spec.</em>
<p>The color specification controls how your application allocates colors
when run on a display with a limited amount of colors, i.e. 8 bit / 256
color displays.
<p>The color specification must be set before you create the QApplication
object.
<p>The choices are:
<ul>
<li> <code>QApplication::NormalColor.</code>
This is the default color allocation strategy. Use this choice if
your application uses buttons, menus, texts and pixmaps with few
colors. With this choice, the application uses system global
colors. This works fine for most applications under X11, but on
Windows machines it may cause dithering of non-standard colors.
<li> <code>QApplication::CustomColor.</code>
Use this choice if your application needs a small number of custom
colors. On X11, this choice is the same as NormalColor. On Windows, Qt
creates a Windows palette, and allocates colors in it on demand.
<li> <code>QApplication::ManyColor.</code>
Use this choice if your application is very color hungry
(e.g. it wants thousands of colors).
Under X11 the effect is: <ul>
<li> For 256-color displays which have at best a 256 color true color
visual, the default visual is used, and colors are allocated
from a color cube.
The color cube is the 6x6x6 (216 color) "Web palette", but the
number of colors can be changed by the <em>-ncols</em> option.
The user can force the application to use the true color visual by
the <a href="#7bcefc">-visual</a>
option.
<li> For 256-color displays which have a true color visual with more
than 256 colors, use that visual. Silicon Graphics X
servers have this feature, for example. They provide an 8
bit visual by default but can deliver true color when
asked.
</ul>
On Windows, Qt creates a Windows palette, and fills it with a color cube.
</ul>
<p>Be aware that the CustomColor and ManyColor choices may lead to colormap
flashing: The foreground application gets (most) of the available
colors, while the background windows will look less good.
<p>Example:
<pre> int main( int argc, char **argv )
{
<a href="#1ee2d1">QApplication::setColorSpec</a>( QApplication::ManyColor );
<a href="qapplication.html">QApplication</a> a( argc, argv );
...
}
</pre>
<p><a href="qcolor.html">QColor</a> provides more functionality for controlling color allocation and
freeing up certain colors. See <a href="qcolor.html#f6b5c7">QColor::enterAllocContext</a>() for more
information.
<p>To see what mode you end up with, you can call <a href="qcolor.html#e9525c">QColor::numBitPlanes</a>()
once the QApplication object exists. A value greater than 8 (typically
16, 24 or 32) means true color.
<p>The color cube used by Qt are all those colors with red, green, and blue
components of either 0x00, 0x33, 0x66, 0x99, 0xCC, or 0xFF.
<p>See also <a href="#fdf8ca">colorSpec</a>(), <a href="qcolor.html#e9525c">QColor::numBitPlanes</a>() and <a href="qcolor.html#f6b5c7">QColor::enterAllocContext</a>().
<p>Examples:
<a href="showimg-main-cpp.html#QApplication::setColorSpec">showimg/main.cpp</a>
<a href="themes-main-cpp.html#QApplication::setColorSpec">themes/main.cpp</a>
<a href="tetrix-tetrix-cpp.html#QApplication::setColorSpec">tetrix/tetrix.cpp</a>
<a href="helpviewer-main-cpp.html#QApplication::setColorSpec">helpviewer/main.cpp</a>
<h3 class="fn">void<a name="483f12"></a>QApplication::setCursorFlashTime(intmsecs) <code>[static]</code></h3>
<p>Sets the text cursor's flash time to <em>msecs</em> milliseconds. The
flash time is the time required to display, invert and restore the
caret display: A full flash cycle. Usually, the text cursor is
displayed for <em>msecs/2</em> milliseconds, then hidden for <em>msecs/2</em>
milliseconds, but this may vary.
<p>Note that on Microsoft Windows, calling this function sets the
cursor flash time for all windows.
<p>See also <a href="#325137">cursorFlashTime</a>().
<h3 class="fn">void<a name="69de52"></a>QApplication::setDefaultCodec(<a href="qtextcodec.html">QTextCodec</a>*codec)</h3>
<p>If the literal quoted text in the program is not in the Latin1
encoding, this function can be used to set the appropriate encoding.
For example, software developed by Korean programmers might use
eucKR for all the text in the program, in which case main() would
be:
<p><pre> main(int argc, char** argv)
{
<a href="qapplication.html">QApplication</a> app(argc, argv);
... install any additional codecs ...
app.<a href="#69de52">setDefaultCodec</a>( <a href="qtextcodec.html#c96cb7">QTextCodec::codecForName</a>("eucKR") );
...
}
</pre>
<p>Note that this is <em>not</em> the way to select the encoding that the <em>user</em> has chosen. For example, to convert an application containing
literal English strings to Korean, all that is needed is for the
English strings to be passed through <a href="qobject.html#2418a9">tr</a>() and for translation files
to be loaded. For details of internationalization, see the <a href="i18n.html">Qt Internationalization documentation</a>.
<p>Note also that some Qt built-in classes call tr() with various
strings. These strings are in English, so for a full translation, a
codec would be required for these strings.
<h3 class="fn">void<a name="7c5fe9"></a>QApplication::setDesktopSettingsAware(boolon) <code>[static]</code></h3>
<p>By default, Qt will try to get the current standard colors, fonts
etc. from the underlying window system's desktop settings (resources),
and use them for all relevant widgets. This behavior can be switched off
by calling this function with <em>on</em> set to FALSE.
<p>This static function must be called before creating the QApplication
object, like this:
<p><pre> int main( int argc, char** argv ) {
<a href="#7c5fe9">QApplication::setDesktopSettingsAware</a>( FALSE ); // I know better than the user
<a href="qapplication.html">QApplication</a> myApp( argc, argv ); // gimme default fonts & colors
...
}
</pre>
<p>See also <a href="#76d935">desktopSettingsAware</a>().
<h3 class="fn">void<a name="315795"></a>QApplication::setDoubleClickInterval(intms) <code>[static]</code></h3>
<p>Sets the time limit that distinguishes a double click from two
consecutive mouse clicks to <em>ms</em> milliseconds.
<p>Note that on Microsoft Windows, calling this function sets the
double click interval for all windows.
<p>See also <a href="#af6c44">doubleClickInterval</a>().
<h3 class="fn">void<a name="f40e3e"></a>QApplication::setEffectEnabled(Qt::UIEffecteffect, boolenable=TRUE) <code>[static]</code></h3>
<p>Enables the UI effect <em>effect</em> if <em>enable</em> is TRUE, otherwise
the effect will not be used.
<p>See also <a href="#6d0b7b">isEffectEnabled</a>(), Qt::UIEffect and <a href="#7c5fe9">setDesktopSettingsAware</a>().
<h3 class="fn">void<a name="3d926a"></a>QApplication::setFont(const<a href="qfont.html">QFont</a>&font, boolinformWidgets=FALSE, constchar*className=0) <code>[static]</code></h3>
<p>Changes the default application font to <em>font.</em> If <em>informWidgets</em> is TRUE, then existing widgets are informed about the
change and thus may adjust themselves to the new application
setting. Otherwise the change only affects newly created widgets. If
<em>className</em> is passed, the change applies only to classes that
inherit <em>className</em> (as reported by <a href="qobject.html#beb5d8">QObject::inherits</a>()).
<p>On application start-up, the default font depends on the window
system. It can vary both with window system version and with
locale. This function lets you override it. Note that overriding
it may be a bad idea, for example some locales need extra-big fonts
to support their special characters.
<p>See also <a href="#f31495">font</a>(), <a href="#9a9177">fontMetrics</a>() and <a href="qwidget.html#090d60">QWidget::setFont</a>().
<p>Examples:
<a href="showimg-main-cpp.html#QApplication::setFont">showimg/main.cpp</a>
<a href="desktop-desktop-cpp.html#setFont">desktop/desktop.cpp</a>
<a href="qfd-qfd-cpp.html#QApplication::setFont">qfd/qfd.cpp</a>
<h3 class="fn">void<a name="978595"></a>QApplication::setGlobalMouseTracking(boolenable) <code>[static]</code></h3>
<p>Enables global mouse tracking if <em>enable</em> is TRUE or disables it
if <em>enable</em> is FALSE.
<p>Enabling global mouse tracking makes it possible for widget event
filters or application event filters to get all mouse move events, even
when no button is depressed. This is useful for special GUI elements,
e.g. tool tips.
<p>Global mouse tracking does not affect widgets and their
mouseMoveEvent(). For a widget to get mouse move events when no button
is depressed, it must do <a href="qwidget.html#36406c">QWidget::setMouseTracking</a>(TRUE).
<p>This function uses an internal counter. Each
setGlobalMouseTracking(TRUE) must have a corresponding
setGlobalMouseTracking(FALSE):
<pre> // at this point global mouse tracking is off
<a href="#978595">QApplication::setGlobalMouseTracking</a>( TRUE );
<a href="#978595">QApplication::setGlobalMouseTracking</a>( TRUE );
<a href="#978595">QApplication::setGlobalMouseTracking</a>( FALSE );
// at this point it's still on
<a href="#978595">QApplication::setGlobalMouseTracking</a>( FALSE );
// but now it's off
</pre>
<p>See also <a href="#6029da">hasGlobalMouseTracking</a>() and <a href="qwidget.html#2831c6">QWidget::hasMouseTracking</a>().
<h3 class="fn">void<a name="1b73fb"></a>QApplication::setGlobalStrut(const<a href="qsize.html">QSize</a>&strut) <code>[static]</code></h3>
<p>Sets the application strut to <em>strut.</em> No GUI-element that
can be interacted with should be smaller than the provided
size. This should be considered when reimplementing items
that may be used on touch-screens or with similar IO-devices.
<p>Example:
<pre> <a href="qsize.html">QSize</a>& WidgetClass::sizeHint() const
{
return QSize( 80, 25 ).expandedTo( <a href="#fcf1bf">QApplication::globalStrut</a>() );
}
</pre>
<p>See also golbalStrut().
<h3 class="fn">void<a name="7ad759"></a>QApplication::setMainWidget(<a href="qwidget.html">QWidget</a>*mainWidget) <code>[virtual]</code></h3>
<p>Sets the main widget of the application.
<p>The main widget is like any other, in most respects except that if
it is deleted, the application exits.
<p>You need not have a main widget; connecting <a href="#4b242c">lastWindowClosed</a>() to <a href="#1af5b8">quit</a>() is
another alternative.
<p>For X11, this function also resizes and moves the main widget
according to the <em>-geometry</em> command-line option, so you should set
the default geometry (using <a href="qwidget.html#9ede68">QWidget::setGeometry())</a> before
calling setMainWidget().
<p>See also <a href="#85380c">mainWidget</a>(), <a href="#84c7bf">exec</a>() and <a href="#1af5b8">quit</a>().
<p>Examples:
<a href="rangecontrols-main-cpp.html#setMainWidget">rangecontrols/main.cpp</a>
<a href="iconview-main-cpp.html#setMainWidget">iconview/main.cpp</a>
<a href="validator-main-cpp.html#setMainWidget">validator/main.cpp</a>
<a href="themes-main-cpp.html#setMainWidget">themes/main.cpp</a>
<a href="listviews-main-cpp.html#setMainWidget">listviews/main.cpp</a>
<a href="aclock-main-cpp.html#setMainWidget">aclock/main.cpp</a>
<a href="checklists-main-cpp.html#setMainWidget">checklists/main.cpp</a>
<a href="drawlines-connect-cpp.html#setMainWidget">drawlines/connect.cpp</a>
<a href="dclock-main-cpp.html#setMainWidget">dclock/main.cpp</a>
<a href="mainlyQt-editor-cpp.html#setMainWidget">mainlyQt/editor.cpp</a>
<a href="xform-xform-cpp.html#setMainWidget">xform/xform.cpp</a>
<a href="cursor-cursor-cpp.html#setMainWidget">cursor/cursor.cpp</a>
<a href="layout-layout-cpp.html#setMainWidget">layout/layout.cpp</a>
<a href="buttongroups-main-cpp.html#setMainWidget">buttongroups/main.cpp</a>
<a href="life-main-cpp.html#setMainWidget">life/main.cpp</a>
<a href="i18n-main-cpp.html#setMainWidget">i18n/main.cpp</a>
<a href="drawdemo-drawdemo-cpp.html#setMainWidget">drawdemo/drawdemo.cpp</a>
<a href="lineedits-main-cpp.html#setMainWidget">lineedits/main.cpp</a>
<a href="popup-popup-cpp.html#setMainWidget">popup/popup.cpp</a>
<a href="fileiconview-main-cpp.html#setMainWidget">fileiconview/main.cpp</a>
<a href="listbox-main-cpp.html#setMainWidget">listbox/main.cpp</a>
<a href="menu-menu-cpp.html#setMainWidget">menu/menu.cpp</a>
<a href="progress-progress-cpp.html#setMainWidget">progress/progress.cpp</a>
<a href="scribble-main-cpp.html#setMainWidget">scribble/main.cpp</a>
<a href="qmag-qmag-cpp.html#setMainWidget">qmag/qmag.cpp</a>
<a href="tabdialog-main-cpp.html#setMainWidget">tabdialog/main.cpp</a>
<a href="splitter-splitter-cpp.html#setMainWidget">splitter/splitter.cpp</a>
<a href="progressbar-main-cpp.html#setMainWidget">progressbar/main.cpp</a>
<a href="tooltip-main-cpp.html#setMainWidget">tooltip/main.cpp</a>
<a href="richtext-main-cpp.html#setMainWidget">richtext/main.cpp</a>
<a href="forever-forever-cpp.html#setMainWidget">forever/forever.cpp</a>
<a href="rot13-rot13-cpp.html#setMainWidget">rot13/rot13.cpp</a>
<a href="xml-tagreader-with-features-tagreader-cpp.html#setMainWidget">xml/tagreader-with-features/tagreader.cpp</a>
<a href="qfd-qfd-cpp.html#setMainWidget">qfd/qfd.cpp</a>
<a href="addressbook-main-cpp.html#setMainWidget">addressbook/main.cpp</a>
<a href="picture-picture-cpp.html#setMainWidget">picture/picture.cpp</a>
<a href="hello-main-cpp.html#setMainWidget">hello/main.cpp</a>
<a href="listboxcombo-main-cpp.html#setMainWidget">listboxcombo/main.cpp</a>
<a href="biff-main-cpp.html#setMainWidget">biff/main.cpp</a>
<a href="tictac-main-cpp.html#setMainWidget">tictac/main.cpp</a>
<a href="customlayout-main-cpp.html#setMainWidget">customlayout/main.cpp</a>
<a href="dirview-main-cpp.html#setMainWidget">dirview/main.cpp</a>
<h3 class="fn">void<a name="07e1f1"></a>QApplication::setOverrideCursor(const<a href="qcursor.html">QCursor</a>&cursor, boolreplace=FALSE) <code>[static]</code></h3>
<p>Sets the application override cursor to <em>cursor.</em>
<p>Application override cursors are intended for showing the user that
the application is in a special state, for example during an
operation that might take some time.
<p>This cursor will be displayed in all the widgets of the application
until <a href="#655095">restoreOverrideCursor</a>() or another setOverrideCursor() is
called.
<p>Application cursors are stored on an internal stack.
setOverrideCursor() pushes the cursor onto the stack, and
restoreOverrideCursor() pops the active cursor off the stack. Every
setOverrideCursor() must eventually be followed by a corresponding
restoreOverrideCursor(), otherwise the stack will never be emptied.
<p>If <em>replace</em> is TRUE, the new cursor will replace the last override
cursor (the stack keeps its depth). If <em>replace</em> is FALSE, the new
stack is pushed onto the top of the stack.
<p>Example:
<pre> <a href="#07e1f1">QApplication::setOverrideCursor</a>( Qt::waitCursor );
calculateHugeMandelbrot(); // lunch time...
<a href="#655095">QApplication::restoreOverrideCursor</a>();
</pre>
<p>See also <a href="#d3b3f8">overrideCursor</a>(), <a href="#655095">restoreOverrideCursor</a>() and <a href="qwidget.html#9b6e22">QWidget::setCursor</a>().
<h3 class="fn">void<a name="63c60d"></a>QApplication::setPalette(const<a href="qpalette.html">QPalette</a>&palette, boolinformWidgets=FALSE, constchar*className=0) <code>[static]</code></h3>
<p>Changes the default application palette to <em>palette.</em> If <em>informWidgets</em> is TRUE, then existing widgets are informed about the
change and thus may adjust themselves to the new application
setting. Otherwise the change only affects newly created widgets. If
<em>className</em> is passed, the change applies only to classes that
inherit <em>className</em> (as reported by <a href="qobject.html#beb5d8">QObject::inherits</a>()).
<p>The palette may be changed according to the current GUI style in
<a href="qstyle.html#07b10b">QStyle::polish</a>().
<p>See also <a href="qwidget.html#d7e4b9">QWidget::setPalette</a>(), <a href="#3e6f87">palette</a>() and <a href="qstyle.html#07b10b">QStyle::polish</a>().
<h3 class="fn">void<a name="414075"></a>QApplication::setStartDragDistance(intl) <code>[static]</code></h3>
<p>Sets the distance after which a drag should start.
<p>See also <a href="#5a44a9">startDragDistance</a>().
<h3 class="fn">void<a name="8f0390"></a>QApplication::setStartDragTime(intms) <code>[static]</code></h3>
<p>Sets the time after which a drag should start.
<p>See also <a href="#66bdb0">startDragTime</a>().
<h3 class="fn">void<a name="e52522"></a>QApplication::setStyle(<a href="qstyle.html">QStyle</a>*style) <code>[static]</code></h3>
<p>Sets the application GUI style to <em>style.</em> Ownership of the style
object is transferred to QApplication, so QApplication will delete
the style object on application exit or when a new style is set.
<p>Example usage:
<pre> <a href="#e52522">QApplication::setStyle</a>( new QWindowStyle );
</pre>
<p>When switching application styles, the color palette is set back to
the initial colors or the system defaults. This is necessary since
certain styles have to adapt the color palette to be fully
style-guide compliant.
<p>See also <a href="#1bada8">style</a>(), <a href="qstyle.html">QStyle</a>, <a href="#63c60d">setPalette</a>() and <a href="#76d935">desktopSettingsAware</a>().
<h3 class="fn">void<a name="ea8301"></a>QApplication::setWheelScrollLines(int<a href="n.html">n</a>) <code>[static]</code></h3>
<p>Sets the number of lines to scroll when the mouse wheel is
rotated.
<p>If this number exceeds the number of visible lines in a certain
widget, the widget should interpret the scroll operation as a single
page up / page down operation instead.
<p>See also <a href="#ebd93c">wheelScrollLines</a>().
<h3 class="fn">void<a name="89739f"></a>QApplication::setWinStyleHighlightColor(const<a href="qcolor.html">QColor</a>&c) <code>[static]</code></h3>
<p><b>This function is obsolete.</b> It is provided to keep old source working, and will probably be removed in a future version of Qt. We strongly advise against using it in new code.<p>
<p>Sets the color used to mark selections in windows style for all widgets
in the application. Will repaint all widgets if the color is changed.
<p>The default color is <code>darkBlue.</code>
<p>See also <a href="#b2c2ef">winStyleHighlightColor</a>().
<h3 class="fn">int<a name="5a44a9"></a>QApplication::startDragDistance() <code>[static]</code></h3>
<p>If you support drag'<a href="n.html">n</a>'drop in you application and a drag should
start after a mouse click and after moving the mouse a certain
distance, you should use the value which this method returns as the
distance. So if the mouse position of the click is stored in <code>startPos</code> and the current position (e.g. in the mouse move event) is
<code>currPos,</code> you can find out if a drag should be started with a code
like this:
<p><pre> if ( ( startPos - currPos ).manhattanLength() > <a href="#5a44a9">QApplication::startDragDistance</a>() )
startTheDrag();
</pre>
<p>Qt internally uses this value too, e.g. in the <a href="qfiledialog.html">QFileDialog</a>.
<p>The default value is set to 4 pixels.
<p>See also <a href="#414075">setStartDragDistance</a>(), <a href="#66bdb0">startDragTime</a>() and <a href="qpoint.html#2fcb0e">QPoint::manhattanLength</a>().
<h3 class="fn">int<a name="66bdb0"></a>QApplication::startDragTime() <code>[static]</code></h3>
<p>If you support drag'<a href="n.html">n</a>'drop in you application and a drag should
start after a mouse click and after a certain time elapsed, you
should use the value which this method returns as delay (in ms).
<p>Qt internally uses also this delay e.g. in <a href="qmultilineedit.html">QMultiLineEdit</a> for
starting a drag.
<p>The default value is set to 500 ms.
<p>See also <a href="#8f0390">setStartDragTime</a>() and <a href="#5a44a9">startDragDistance</a>().
<h3 class="fn">bool<a name="a61363"></a>QApplication::startingUp() <code>[static]</code></h3>
<p>Returns TRUE if an application object has not been created yet.
<p>See also <a href="#568523">closingDown</a>().
<h3 class="fn"><a href="qstyle.html">QStyle</a>&<a name="1bada8"></a>QApplication::style() <code>[static]</code></h3>
<p>Returns the style object of the application.
<p>See also <a href="#e52522">setStyle</a>() and <a href="qstyle.html">QStyle</a>.
<h3 class="fn">void<a name="9cd282"></a>QApplication::syncX() <code>[static]</code></h3>
<p>Synchronizes with the X server in the X11 implementation. This
normally takes some time. Does nothing on other platforms.
<p>See also <a href="#0965b7">flushX</a>().
<h3 class="fn">QWidgetList*<a name="7b4eb5"></a>QApplication::topLevelWidgets() <code>[static]</code></h3>
<p>Returns a list of the top level widgets in the application.
<p>The list is created using <code>new</code> and must be deleted by the caller.
<p>The list is empty (<a href="qlist.html#10b215">QList::isEmpty</a>()) if there are no top level
widgets.
<p>Note that some of the top level widgets may be hidden, for example
the tooltip if no tooltip is currently shown.
<p>Example:
<pre> //
// Shows all hidden top level widgets.
//
QWidgetList *list = QApplication::topLevelWidgets();
QWidgetListIt it( *list ); // iterate over the widgets
<a href="qwidget.html">QWidget</a> * w;
while ( (w=it.current()) != 0 ) { // for each top level widget...
++it;
if ( !w-><a href="qwidget.html#4d2aa7">isVisible</a>() )
w-><a href="qwidget.html#200ee5">show</a>();
}
delete list; // delete the list, not the widgets
</pre>
<p><b>Warning:</b> Delete the list away as soon you have finished using it.
The widgets in the list may be deleted by someone else at any time.
<p>See also <a href="#504f8c">allWidgets</a>(), <a href="qwidget.html#17338a">QWidget::isTopLevel</a>(), <a href="qwidget.html#4d2aa7">QWidget::isVisible</a>() and <a href="qlist.html#10b215">QList::isEmpty</a>().
<h3 class="fn"><a href="qstring.html">QString</a><a name="35f6de"></a>QApplication::translate(constchar*scope, constchar*key, constchar*comment)const</h3>
<p>Returns the translation text for <em>key,</em> by querying the installed
messages files. The message file that was installed last is asked
first.
<p><a href="qobject.html#2418a9">QObject::tr</a>() offers a more convenient way to use this functionality.
<p><em>context</em> is typically a class name (e.g. <code>MyDialog)</code> and <em>key</em> is
either English text or a short marker text, if the output text will
be very long (as for help texts).
<p><em>comment</em> is a disambiguating comment, for when the same text is
used in different roles within one context.
<p>See the <a href="qtranslator.html">QTranslator</a> documentation for more information about keys,
contexts and comments.
<p>If none of the message files contain a translation for <em>key</em> in <em>scope,</em> this function returns <em>key.</em>
<p>This function is not virtual, but you can add alternative translation
techniques by installing subclasses of QTranslator.
<p>See also <a href="qobject.html#2418a9">QObject::tr</a>(), <a href="#e8df5e">installTranslator</a>(), <a href="#8e6099">removeTranslator</a>() and <a href="qtranslator.html">QTranslator</a>.
<h3 class="fn"><a href="qstring.html">QString</a><a name="41adba"></a>QApplication::translate(constchar*context, constchar*key)const</h3>
<p><b>This function is obsolete.</b> It is provided to keep old source working, and will probably be removed in a future version of Qt. We strongly advise against using it in new code.<p>This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
<p>This version of the function uses "" as comment.
<h3 class="fn">void<a name="cc10ca"></a>QApplication::unlock(boolwakeUpGui=TRUE)</h3>
<p>Unlock the Qt library mutex. if <em>wakeUpGui</em> is TRUE (default argument),
then the GUI thread will be woken with <a href="#294481">QApplication::wakeUpGuiThread</a>().
<p>See also <a href="#e7d891">lock</a>() and <a href="#8b7475">locked</a>().
<h3 class="fn">void<a name="294481"></a>QApplication::wakeUpGuiThread()</h3>
<p>Wakes up the GUI thread.
<p>See also <a href="#611442">guiThreadAwake</a>().
<h3 class="fn">int<a name="ebd93c"></a>QApplication::wheelScrollLines() <code>[static]</code></h3>
<p>Returns the number of lines to scroll when the mouse wheel is rotated.
<p>See also <a href="#ea8301">setWheelScrollLines</a>().
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="48ddf6"></a>QApplication::widgetAt(intx, inty, boolchild=FALSE) <code>[static]</code></h3>
<p>Returns a pointer to the widget at global screen position <em>(x,y),</em> or a
null pointer if there is no Qt widget there.
<p>If <em>child</em> is FALSE and there is a child widget at position <em>(x,y),</em> the top-level widget containing it is returned. If <em>child</em>
is TRUE the child widget at position <em>(x,y)</em> is returned.
<p>This function is normally rather slow.
<p>See also <a href="qcursor.html#5bce2b">QCursor::pos</a>(), <a href="qwidget.html#5bdd5f">QWidget::grabMouse</a>() and <a href="qwidget.html#6830ee">QWidget::grabKeyboard</a>().
<h3 class="fn"><a href="qwidget.html">QWidget</a>*<a name="bf71e7"></a>QApplication::widgetAt(const<a href="qpoint.html">QPoint</a>&pos, boolchild=FALSE) <code>[static]</code></h3>
<p>This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
<h3 class="fn">const<a href="qcolor.html">QColor</a>&<a name="b2c2ef"></a>QApplication::winStyleHighlightColor() <code>[static]</code></h3>
<p><b>This function is obsolete.</b> It is provided to keep old source working, and will probably be removed in a future version of Qt. We strongly advise against using it in new code.<p>
<p>Returns the color used to mark selections in windows style.
<p>See also <a href="#89739f">setWinStyleHighlightColor</a>().
<hr><h2>Related Functions</h2>
<h3>void <a name="0e1d68"></a>qFatal (const char * msg, ...)</h3>
<p>Prints a fatal error message and exits, or calls the message handler (if it
has been installed).
<p>This function takes a format string and a list of arguments, similar to
the C printf() function.
<p>Example:
<pre> int divide( int a, int b )
{
if ( b == 0 ) // program error
<a href="qapplication.html#0e1d68">qFatal</a>( "divide: cannot divide by zero" );
return a/b;
}
</pre>
<p>Under X11, the text is printed to stderr. Under Windows, the text is
sent to the debugger.<p><b>Warning:</b> The internal buffer is limited to 8196 bytes (including the
0-terminator).
<p>See also <a href="qapplication.html#72e78c">qDebug</a>(), <a href="qapplication.html#290ef4">qWarning</a>(), <a href="qapplication.html#a8a31b">qInstallMsgHandler</a>() and <a href="debug.html">Debugging</a>
<h3>void <a name="290ef4"></a>qWarning (const char * msg, ...)</h3>
<p>Prints a warning message, or calls the message handler (if it has been
installed).
<p>This function takes a format string and a list of arguments, similar to
the C printf() function.
<p>Example:
<pre> void f( int c )
{
if ( c > 200 )
<a href="qapplication.html#290ef4">qWarning</a>( "f: bad argument, c == %d", c );
}
</pre>
<p>Under X11, the text is printed to stderr. Under Windows, the text is
sent to the debugger.<p><b>Warning:</b> The internal buffer is limited to 8196 bytes (including the
0-terminator).
<p>See also <a href="qapplication.html#72e78c">qDebug</a>(), <a href="qapplication.html#0e1d68">qFatal</a>(), <a href="qapplication.html#a8a31b">qInstallMsgHandler</a>() and <a href="debug.html">Debugging</a>
<p>Examples:
<a href="life-main-cpp.html#qWarning">life/main.cpp</a>
<a href="progress-progress-cpp.html#qWarning">progress/progress.cpp</a>
<a href="tictac-main-cpp.html#qWarning">tictac/main.cpp</a>
<h3>const char * <a name="59b07d"></a>qVersion ()</h3>
<p>Returns the Qt version number for the library, typically "1.30"
or "2.1.0".
<h3>void <a name="6382b3"></a>qAddPostRoutine (Q_CleanUpFunction p)</h3>
<p>Adds a global routine that will be called from the QApplication
destructor. This function is normally used to add cleanup routines
for program-wide functionality.
<p>The function given by <em>p</em> should take no arguments and return
nothing, like this:
<pre> static int *global_ptr = 0;
static void cleanup_ptr()
{
delete [] global_ptr;
global_ptr = 0;
}
void init_ptr()
{
global_ptr = new int[100]; // allocate data
<a href="qapplication.html#6382b3">qAddPostRoutine</a>( cleanup_ptr ); // delete later
}
</pre>
<p>Note that for an application- or module-wide cleanup,
qAddPostRoutine() is often not suitable. People have a tendency to
make such modules dynamically loaded, and then unload those modules
long before the QApplication destructor is called, for example.
<p>For modules and libraries, using a reference-counted initialization
manager or Qt' parent-child delete mechanism may be better. Here is
an example of a private class which uses the parent-child mechanism
to call a cleanup function at the right time:
<p><pre> class MyPrivateInitStuff: public QObject {
private:
MyPrivateInitStuff( <a href="qobject.html">QObject</a> * parent ): <a href="qobject.html">QObject</a>( parent) {
// initialization goes here
}
MyPrivateInitStuff * p;
public:
static MyPrivateInitStuff * initStuff( <a href="qobject.html">QObject</a> * parent ) {
if ( !p )
p = new MyPrivateInitStuff( parent );
return p;
}
~MyPrivateInitStuff() {
// cleanup (the "post routine") goes here
}
}
</pre>
<p>By selecting the right parent widget/object, this can often be made
to clean up the module's data at the exact right moment.
<h3>void <a name="6c7a8c"></a>ASSERT (bool test)</h3>
<p>Prints a warning message containing the source code file name and line number
if <em>test</em> is FALSE.
<p>This is really a macro defined in <a href="qglobal-h.html">qglobal.h</a>.
<p>ASSERT is useful for testing required conditions in your program.
<p>Example:
<pre> //
// File: div.cpp
//
#include <qglobal.h>
int divide( int a, int b )
{
ASSERT( b != 0 ); // this is line 9
return a/b;
}
</pre>
<p>If <code>b</code> is zero, the ASSERT statement will output the following message
using the <a href="qapplication.html#290ef4">qWarning</a>() function:
<pre> ASSERT: "b == 0" in div.cpp (9)
</pre>
<p>See also <a href="qapplication.html#290ef4">qWarning</a>() and <a href="debug.html">Debugging</a>
<h3>void <a name="72e78c"></a>qDebug (const char * msg, ...)</h3>
<p>Prints a debug message, or calls the message handler (if it has been
installed).
<p>This function takes a format string and a list of arguments, similar to
the C printf() function.
<p>Example:
<pre> <a href="qapplication.html#72e78c">qDebug</a>( "my window handle = %x", myWidget->id() );
</pre>
<p>Under X11, the text is printed to stderr. Under Windows, the text is
sent to the debugger.<p><b>Warning:</b> The internal buffer is limited to 8196 bytes (including the
0-terminator).
<p>See also <a href="qapplication.html#290ef4">qWarning</a>(), <a href="qapplication.html#0e1d68">qFatal</a>(), <a href="qapplication.html#a8a31b">qInstallMsgHandler</a>() and <a href="debug.html">Debugging</a>
<h3>bool <a name="7e6130"></a>qSysInfo (int * wordSize, bool * bigEndian)</h3>
<p>Obtains information about the system.
<p>The system's word size in bits (typically 32) is returned in <em>*wordSize.</em>
The <em>*bigEndian</em> is set to TRUE if this is a big-endian machine,
or to FALSE if this is a little-endian machine.
<p>This function calls <a href="qapplication.html#0e1d68">qFatal</a>() with a message if the computer is truly weird
(i.e. different endianness for 16 bit and 32 bit integers).
<h3>void <a name="7ed4c6"></a>CHECK_PTR (void * p)</h3>
<p>If <em>p</em> is null, a fatal messages says that the program ran out of memory
and exits. If <em>p</em> is not null, nothing happens.
<p>This is really a macro defined in <a href="qglobal-h.html">qglobal.h</a>.
<p>Example:
<pre> int *a;
CHECK_PTR( a = new int[80] ); // never do this!
// do this instead:
a = new int[80];
CHECK_PTR( a ); // this is fine
</pre>
<p>See also <a href="qapplication.html#0e1d68">qFatal</a>() and <a href="debug.html">Debugging</a>
<h3>msg_handler <a name="a8a31b"></a>qInstallMsgHandler (msg_handler h)</h3>
<p>Installs a Qt message handler. Returns a pointer to the message handler
previously defined.
<p>The message handler is a function that prints out debug messages,
warnings and fatal error messages. The Qt library (debug version)
contains hundreds of warning messages that are printed when internal
errors (usually invalid function arguments) occur. If you implement
your own message handler, you get total control of these messages.
<p>The default message handler prints the message to the standard output
under X11 or to the debugger under Windows. If it is a fatal message,
the application aborts immediately.
<p>Only one message handler can be defined, since this is usually done on
an application-wide basis to control debug output.
<p>To restore the message handler, call <code>qInstallMsgHandler(0).</code>
<p>Example:
<pre> #include <qapplication.h>
#include <stdio.h>
#include <stdlib.h>
void myMessageOutput( QtMsgType type, const char *msg )
{
switch ( type ) {
case QtDebugMsg:
fprintf( stderr, "Debug: %s\n", msg );
break;
case QtWarningMsg:
fprintf( stderr, "Warning: %s\n", msg );
break;
case QtFatalMsg:
fprintf( stderr, "Fatal: %s\n", msg );
abort(); // dump core on purpose
}
}
int main( int argc, char **argv )
{
<a href="qapplication.html#a8a31b">qInstallMsgHandler</a>( myMessageOutput );
<a href="qapplication.html">QApplication</a> a( argc, argv );
...
return a.<a href="qapplication.html#84c7bf">exec</a>();
}
</pre>
<p>See also <a href="qapplication.html#72e78c">qDebug</a>(), <a href="qapplication.html#290ef4">qWarning</a>(), <a href="qapplication.html#0e1d68">qFatal</a>() and <a href="debug.html">Debugging</a>
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