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32<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QApplication Class Reference</h1>
33
34<p>The QApplication class manages the GUI application's control
35flow and main settings.
36<a href="#details">More...</a>
37<p><tt>#include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;</tt>
38<p>Inherits <a href="qobject.html">QObject</a>.
39<p><a href="qapplication-members.html">List of all member functions.</a>
40<h2>Public Members</h2>
41<ul>
42<li class=fn><a href="#QApplication"><b>QApplication</b></a> ( int&nbsp;&amp;&nbsp;argc, char&nbsp;**&nbsp;argv )</li>
43<li class=fn><a href="#QApplication-2"><b>QApplication</b></a> ( int&nbsp;&amp;&nbsp;argc, char&nbsp;**&nbsp;argv, bool&nbsp;GUIenabled )</li>
44<li class=fn>enum <a href="#Type-enum"><b>Type</b></a> { Tty, GuiClient, GuiServer }</li>
45<li class=fn><a href="#QApplication-3"><b>QApplication</b></a> ( int&nbsp;&amp;&nbsp;argc, char&nbsp;**&nbsp;argv, Type&nbsp;type )</li>
46<li class=fn><a href="#QApplication-4"><b>QApplication</b></a> ( Display&nbsp;*&nbsp;dpy, HANDLE&nbsp;visual = 0, HANDLE&nbsp;colormap = 0 )</li>
47<li class=fn><a href="#QApplication-5"><b>QApplication</b></a> ( Display&nbsp;*&nbsp;dpy, int&nbsp;argc, char&nbsp;**&nbsp;argv, HANDLE&nbsp;visual = 0, HANDLE&nbsp;colormap = 0 )</li>
48<li class=fn>virtual <a href="#~QApplication"><b>~QApplication</b></a> ()</li>
49<li class=fn>int <a href="#argc"><b>argc</b></a> () const</li>
50<li class=fn>char ** <a href="#argv"><b>argv</b></a> () const</li>
51<li class=fn>Type <a href="#type"><b>type</b></a> () const</li>
52<li class=fn>enum <a href="#ColorSpec-enum"><b>ColorSpec</b></a> { NormalColor = 0, CustomColor = 1, ManyColor = 2 }</li>
53<li class=fn>QWidget * <a href="#mainWidget"><b>mainWidget</b></a> () const</li>
54<li class=fn>virtual void <a href="#setMainWidget"><b>setMainWidget</b></a> ( QWidget&nbsp;*&nbsp;mainWidget )</li>
55<li class=fn>virtual void <a href="#polish"><b>polish</b></a> ( QWidget&nbsp;*&nbsp;w )</li>
56<li class=fn>QWidget * <a href="#focusWidget"><b>focusWidget</b></a> () const</li>
57<li class=fn>QWidget * <a href="#activeWindow"><b>activeWindow</b></a> () const</li>
58<li class=fn>int <a href="#exec"><b>exec</b></a> ()</li>
59<li class=fn>void <a href="#processEvents"><b>processEvents</b></a> ()</li>
60<li class=fn>void <a href="#processEvents-2"><b>processEvents</b></a> ( int&nbsp;maxtime )</li>
61<li class=fn>void processOneEvent () &nbsp;<em>(obsolete)</em></li>
62<li class=fn>bool <a href="#hasPendingEvents"><b>hasPendingEvents</b></a> ()</li>
63<li class=fn>int enter_loop () &nbsp;<em>(obsolete)</em></li>
64<li class=fn>void exit_loop () &nbsp;<em>(obsolete)</em></li>
65<li class=fn>int loopLevel () const &nbsp;<em>(obsolete)</em></li>
66<li class=fn>virtual bool <a href="#notify"><b>notify</b></a> ( QObject&nbsp;*&nbsp;receiver, QEvent&nbsp;*&nbsp;e )</li>
67<li class=fn>void setDefaultCodec ( QTextCodec&nbsp;*&nbsp;codec ) &nbsp;<em>(obsolete)</em></li>
68<li class=fn>QTextCodec * defaultCodec () const &nbsp;<em>(obsolete)</em></li>
69<li class=fn>void <a href="#installTranslator"><b>installTranslator</b></a> ( QTranslator&nbsp;*&nbsp;mf )</li>
70<li class=fn>void <a href="#removeTranslator"><b>removeTranslator</b></a> ( QTranslator&nbsp;*&nbsp;mf )</li>
71<li class=fn>enum <a href="#Encoding-enum"><b>Encoding</b></a> { DefaultCodec, UnicodeUTF8 }</li>
72<li class=fn>QString <a href="#translate"><b>translate</b></a> ( const&nbsp;char&nbsp;*&nbsp;context, const&nbsp;char&nbsp;*&nbsp;sourceText, const&nbsp;char&nbsp;*&nbsp;comment = 0, Encoding&nbsp;encoding = DefaultCodec ) const</li>
73<li class=fn>QString <a href="#applicationDirPath"><b>applicationDirPath</b></a> ()</li>
74<li class=fn>QString <a href="#applicationFilePath"><b>applicationFilePath</b></a> ()</li>
75<li class=fn>virtual bool <a href="#macEventFilter"><b>macEventFilter</b></a> ( EventHandlerCallRef, EventRef )</li>
76<li class=fn>virtual bool <a href="#winEventFilter"><b>winEventFilter</b></a> ( MSG * )</li>
77<li class=fn>virtual bool <a href="#x11EventFilter"><b>x11EventFilter</b></a> ( XEvent * )</li>
78<li class=fn>int <a href="#x11ProcessEvent"><b>x11ProcessEvent</b></a> ( XEvent&nbsp;*&nbsp;event )</li>
79<li class=fn>virtual bool <a href="#qwsEventFilter"><b>qwsEventFilter</b></a> ( QWSEvent * )</li>
80<li class=fn>void <a href="#qwsSetCustomColors"><b>qwsSetCustomColors</b></a> ( QRgb&nbsp;*&nbsp;colorTable, int&nbsp;start, int&nbsp;numColors )</li>
81<li class=fn>void <a href="#winFocus"><b>winFocus</b></a> ( QWidget&nbsp;*&nbsp;widget, bool&nbsp;gotFocus )</li>
82<li class=fn>bool <a href="#isSessionRestored"><b>isSessionRestored</b></a> () const</li>
83<li class=fn>QString <a href="#sessionId"><b>sessionId</b></a> () const</li>
84<li class=fn>QString <a href="#sessionKey"><b>sessionKey</b></a> () const</li>
85<li class=fn>virtual void <a href="#commitData"><b>commitData</b></a> ( QSessionManager&nbsp;&amp;&nbsp;sm )</li>
86<li class=fn>virtual void <a href="#saveState"><b>saveState</b></a> ( QSessionManager&nbsp;&amp;&nbsp;sm )</li>
87<li class=fn>void <a href="#wakeUpGuiThread"><b>wakeUpGuiThread</b></a> ()</li>
88<li class=fn>void <a href="#lock"><b>lock</b></a> ()</li>
89<li class=fn>void <a href="#unlock"><b>unlock</b></a> ( bool&nbsp;wakeUpGui = TRUE )</li>
90<li class=fn>bool <a href="#locked"><b>locked</b></a> ()</li>
91<li class=fn>bool <a href="#tryLock"><b>tryLock</b></a> ()</li>
92</ul>
93<h2>Public Slots</h2>
94<ul>
95<li class=fn>void <a href="#quit"><b>quit</b></a> ()</li>
96<li class=fn>void <a href="#closeAllWindows"><b>closeAllWindows</b></a> ()</li>
97<li class=fn>void <a href="#aboutQt"><b>aboutQt</b></a> ()</li>
98</ul>
99<h2>Signals</h2>
100<ul>
101<li class=fn>void <a href="#lastWindowClosed"><b>lastWindowClosed</b></a> ()</li>
102<li class=fn>void <a href="#aboutToQuit"><b>aboutToQuit</b></a> ()</li>
103<li class=fn>void <a href="#guiThreadAwake"><b>guiThreadAwake</b></a> ()</li>
104</ul>
105<h2>Static Public Members</h2>
106<ul>
107<li class=fn>QStyle &amp; <a href="#style"><b>style</b></a> ()</li>
108<li class=fn>void <a href="#setStyle"><b>setStyle</b></a> ( QStyle&nbsp;*&nbsp;style )</li>
109<li class=fn>QStyle * <a href="#setStyle-2"><b>setStyle</b></a> ( const&nbsp;QString&nbsp;&amp;&nbsp;style )</li>
110<li class=fn>int <a href="#colorSpec"><b>colorSpec</b></a> ()</li>
111<li class=fn>void <a href="#setColorSpec"><b>setColorSpec</b></a> ( int&nbsp;spec )</li>
112<li class=fn>QCursor * <a href="#overrideCursor"><b>overrideCursor</b></a> ()</li>
113<li class=fn>void <a href="#setOverrideCursor"><b>setOverrideCursor</b></a> ( const&nbsp;QCursor&nbsp;&amp;&nbsp;cursor, bool&nbsp;replace = FALSE )</li>
114<li class=fn>void <a href="#restoreOverrideCursor"><b>restoreOverrideCursor</b></a> ()</li>
115<li class=fn>bool <a href="#hasGlobalMouseTracking"><b>hasGlobalMouseTracking</b></a> ()</li>
116<li class=fn>void <a href="#setGlobalMouseTracking"><b>setGlobalMouseTracking</b></a> ( bool&nbsp;enable )</li>
117<li class=fn>QPalette <a href="#palette"><b>palette</b></a> ( const&nbsp;QWidget&nbsp;*&nbsp;w = 0 )</li>
118<li class=fn>void <a href="#setPalette"><b>setPalette</b></a> ( const&nbsp;QPalette&nbsp;&amp;&nbsp;palette, bool&nbsp;informWidgets = FALSE, const&nbsp;char&nbsp;*&nbsp;className = 0 )</li>
119<li class=fn>QFont <a href="#font"><b>font</b></a> ( const&nbsp;QWidget&nbsp;*&nbsp;w = 0 )</li>
120<li class=fn>void <a href="#setFont"><b>setFont</b></a> ( const&nbsp;QFont&nbsp;&amp;&nbsp;font, bool&nbsp;informWidgets = FALSE, const&nbsp;char&nbsp;*&nbsp;className = 0 )</li>
121<li class=fn>QFontMetrics <a href="#fontMetrics"><b>fontMetrics</b></a> ()</li>
122<li class=fn>QWidgetList * <a href="#allWidgets"><b>allWidgets</b></a> ()</li>
123<li class=fn>QWidgetList * <a href="#topLevelWidgets"><b>topLevelWidgets</b></a> ()</li>
124<li class=fn>QDesktopWidget * <a href="#desktop"><b>desktop</b></a> ()</li>
125<li class=fn>QWidget * <a href="#activePopupWidget"><b>activePopupWidget</b></a> ()</li>
126<li class=fn>QWidget * <a href="#activeModalWidget"><b>activeModalWidget</b></a> ()</li>
127<li class=fn>QClipboard * <a href="#clipboard"><b>clipboard</b></a> ()</li>
128<li class=fn>QWidget * <a href="#widgetAt"><b>widgetAt</b></a> ( int&nbsp;x, int&nbsp;y, bool&nbsp;child = FALSE )</li>
129<li class=fn>QWidget * <a href="#widgetAt-2"><b>widgetAt</b></a> ( const&nbsp;QPoint&nbsp;&amp;&nbsp;pos, bool&nbsp;child = FALSE )</li>
130<li class=fn>QEventLoop * <a href="#eventLoop"><b>eventLoop</b></a> ()</li>
131<li class=fn>void <a href="#exit"><b>exit</b></a> ( int&nbsp;retcode = 0 )</li>
132<li class=fn>bool <a href="#sendEvent"><b>sendEvent</b></a> ( QObject&nbsp;*&nbsp;receiver, QEvent&nbsp;*&nbsp;event )</li>
133<li class=fn>void <a href="#postEvent"><b>postEvent</b></a> ( QObject&nbsp;*&nbsp;receiver, QEvent&nbsp;*&nbsp;event )</li>
134<li class=fn>void <a href="#sendPostedEvents"><b>sendPostedEvents</b></a> ( QObject&nbsp;*&nbsp;receiver, int&nbsp;event_type )</li>
135<li class=fn>void <a href="#sendPostedEvents-2"><b>sendPostedEvents</b></a> ()</li>
136<li class=fn>void <a href="#removePostedEvents"><b>removePostedEvents</b></a> ( QObject&nbsp;*&nbsp;receiver )</li>
137<li class=fn>bool <a href="#startingUp"><b>startingUp</b></a> ()</li>
138<li class=fn>bool <a href="#closingDown"><b>closingDown</b></a> ()</li>
139<li class=fn>void <a href="#flushX"><b>flushX</b></a> ()</li>
140<li class=fn>void <a href="#flush"><b>flush</b></a> ()</li>
141<li class=fn>void <a href="#syncX"><b>syncX</b></a> ()</li>
142<li class=fn>void <a href="#beep"><b>beep</b></a> ()</li>
143<li class=fn>void setWinStyleHighlightColor ( const&nbsp;QColor&nbsp;&amp;&nbsp;c ) &nbsp;<em>(obsolete)</em></li>
144<li class=fn>const QColor &amp; winStyleHighlightColor () &nbsp;<em>(obsolete)</em></li>
145<li class=fn>void <a href="#setDesktopSettingsAware"><b>setDesktopSettingsAware</b></a> ( bool&nbsp;on )</li>
146<li class=fn>bool <a href="#desktopSettingsAware"><b>desktopSettingsAware</b></a> ()</li>
147<li class=fn>void <a href="#setCursorFlashTime"><b>setCursorFlashTime</b></a> ( int&nbsp;msecs )</li>
148<li class=fn>int <a href="#cursorFlashTime"><b>cursorFlashTime</b></a> ()</li>
149<li class=fn>void <a href="#setDoubleClickInterval"><b>setDoubleClickInterval</b></a> ( int&nbsp;ms )</li>
150<li class=fn>int <a href="#doubleClickInterval"><b>doubleClickInterval</b></a> ()</li>
151<li class=fn>void <a href="#setWheelScrollLines"><b>setWheelScrollLines</b></a> ( int&nbsp;n )</li>
152<li class=fn>int <a href="#wheelScrollLines"><b>wheelScrollLines</b></a> ()</li>
153<li class=fn>void <a href="#setGlobalStrut"><b>setGlobalStrut</b></a> ( const&nbsp;QSize&nbsp;&amp;&nbsp;strut )</li>
154<li class=fn>QSize <a href="#globalStrut"><b>globalStrut</b></a> ()</li>
155<li class=fn>void <a href="#setLibraryPaths"><b>setLibraryPaths</b></a> ( const&nbsp;QStringList&nbsp;&amp;&nbsp;paths )</li>
156<li class=fn>QStringList <a href="#libraryPaths"><b>libraryPaths</b></a> ()</li>
157<li class=fn>void <a href="#addLibraryPath"><b>addLibraryPath</b></a> ( const&nbsp;QString&nbsp;&amp;&nbsp;path )</li>
158<li class=fn>void <a href="#removeLibraryPath"><b>removeLibraryPath</b></a> ( const&nbsp;QString&nbsp;&amp;&nbsp;path )</li>
159<li class=fn>void <a href="#setStartDragTime"><b>setStartDragTime</b></a> ( int&nbsp;ms )</li>
160<li class=fn>int <a href="#startDragTime"><b>startDragTime</b></a> ()</li>
161<li class=fn>void <a href="#setStartDragDistance"><b>setStartDragDistance</b></a> ( int&nbsp;l )</li>
162<li class=fn>int <a href="#startDragDistance"><b>startDragDistance</b></a> ()</li>
163<li class=fn>void <a href="#setReverseLayout"><b>setReverseLayout</b></a> ( bool&nbsp;b )</li>
164<li class=fn>bool <a href="#reverseLayout"><b>reverseLayout</b></a> ()</li>
165<li class=fn>int <a href="#horizontalAlignment"><b>horizontalAlignment</b></a> ( int&nbsp;align )</li>
166<li class=fn>bool <a href="#isEffectEnabled"><b>isEffectEnabled</b></a> ( Qt::UIEffect&nbsp;effect )</li>
167<li class=fn>void <a href="#setEffectEnabled"><b>setEffectEnabled</b></a> ( Qt::UIEffect&nbsp;effect, bool&nbsp;enable = TRUE )</li>
168<li class=fn>QWSDecoration &amp; <a href="#qwsDecoration"><b>qwsDecoration</b></a> ()</li>
169<li class=fn>void <a href="#qwsSetDecoration"><b>qwsSetDecoration</b></a> ( QWSDecoration&nbsp;*&nbsp;d )</li>
170</ul>
171<h2>Related Functions</h2>
172<ul>
173<li class=fn>void <a href="#qAddPostRoutine"><b>qAddPostRoutine</b></a> ( QtCleanUpFunction&nbsp;p )</li>
174<li class=fn>const char * <a href="#qVersion"><b>qVersion</b></a> ()</li>
175<li class=fn>bool <a href="#qSysInfo"><b>qSysInfo</b></a> ( int&nbsp;*&nbsp;wordSize, bool&nbsp;*&nbsp;bigEndian )</li>
176<li class=fn>void <a href="#qDebug"><b>qDebug</b></a> ( const&nbsp;char&nbsp;*&nbsp;msg, ... )</li>
177<li class=fn>void <a href="#qWarning"><b>qWarning</b></a> ( const&nbsp;char&nbsp;*&nbsp;msg, ... )</li>
178<li class=fn>void <a href="#qFatal"><b>qFatal</b></a> ( const&nbsp;char&nbsp;*&nbsp;msg, ... )</li>
179<li class=fn>void <a href="#qSystemWarning"><b>qSystemWarning</b></a> ( const&nbsp;char&nbsp;*&nbsp;msg, int&nbsp;code )</li>
180<li class=fn>void <a href="#Q_ASSERT"><b>Q_ASSERT</b></a> ( bool&nbsp;test )</li>
181<li class=fn>void <a href="#Q_CHECK_PTR"><b>Q_CHECK_PTR</b></a> ( void&nbsp;*&nbsp;p )</li>
182<li class=fn>QtMsgHandler <a href="#qInstallMsgHandler"><b>qInstallMsgHandler</b></a> ( QtMsgHandler&nbsp;h )</li>
183</ul>
184<hr><a name="details"></a><h2>Detailed Description</h2>
185
186
187The QApplication class manages the GUI application's control
188flow and main settings.
189<p>
190
191<p> It contains the main event loop, where all events from the window
192system and other sources are processed and dispatched. It also
193handles the application's initialization and finalization, and
194provides session management. It also handles most system-wide and
195application-wide settings.
196<p> For any GUI application that uses Qt, there is precisely one
197QApplication object, no matter whether the application has 0, 1, 2
198or more windows at any time.
199<p> The QApplication object is accessible through the global pointer <tt>qApp</tt>. Its main areas of responsibility are:
200<ul>
201<p> <li> It initializes the application with the user's desktop settings
202such as <a href="#palette">palette</a>(), <a href="#font">font</a>() and <a href="#doubleClickInterval">doubleClickInterval</a>(). It keeps track
203of these properties in case the user changes the desktop globally, for
204example through some kind of control panel.
205<p> <li> It performs event handling, meaning that it receives events
206from the underlying window system and dispatches them to the relevant
207widgets. By using <a href="#sendEvent">sendEvent</a>() and <a href="#postEvent">postEvent</a>() you can send your own
208events to widgets.
209<p> <li> It parses common command line arguments and sets its internal
210state accordingly. See the <a href="#QApplication">constructor documentation</a> below for more details about this.
211<p> <li> It defines the application's look and feel, which is
212encapsulated in a <a href="qstyle.html">QStyle</a> object. This can be changed at runtime
213with <a href="#setStyle">setStyle</a>().
214<p> <li> It specifies how the application is to allocate colors.
215See <a href="#setColorSpec">setColorSpec</a>() for details.
216<p> <li> It provides <a href="i18n.html#localization">localization</a> of strings that are visible to the user
217via <a href="#translate">translate</a>().
218<p> <li> It provides some magical objects like the <a href="#desktop">desktop</a>() and the
219<a href="#clipboard">clipboard</a>().
220<p> <li> It knows about the application's windows. You can ask which
221widget is at a certain position using <a href="#widgetAt">widgetAt</a>(), get a list of
222<a href="#topLevelWidgets">topLevelWidgets</a>() and <a href="#closeAllWindows">closeAllWindows</a>(), etc.
223<p> <li> It manages the application's mouse cursor handling,
224see <a href="#setOverrideCursor">setOverrideCursor</a>() and <a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>().
225<p> <li> On the X window system, it provides functions to flush and sync
226the communication stream, see <a href="#flushX">flushX</a>() and <a href="#syncX">syncX</a>().
227<p> <li> It provides support for sophisticated <a href="session.html">session management</a>. This makes it possible
228for applications to terminate gracefully when the user logs out, to
229cancel a shutdown process if termination isn't possible and even to
230preserve the entire application's state for a future session. See
231<a href="#isSessionRestored">isSessionRestored</a>(), <a href="#sessionId">sessionId</a>() and <a href="#commitData">commitData</a>() and <a href="#saveState">saveState</a>()
232for details.
233<p> </ul>
234<p> The <a href="simple-application.html">Application walk-through
235example</a> contains a typical complete main() that does the usual
236things with QApplication.
237<p> Since the QApplication object does so much initialization, it
238<b>must</b> be created before any other objects related to the user
239interface are created.
240<p> Since it also deals with common command line arguments, it is
241usually a good idea to create it <em>before</em> any interpretation or
242modification of <tt>argv</tt> is done in the application itself. (Note
243also that for X11, <a href="#setMainWidget">setMainWidget</a>() may change the main widget
244according to the <tt>-geometry</tt> option. To preserve this
245functionality, you must set your defaults before setMainWidget() and
246any overrides after.)
247<p> <center><table cellpadding="4" cellspacing="2" border="0">
248<tr bgcolor="#a2c511"> <th valign="top" colspan="2" rowspan="1"> Groups of functions
249<tr bgcolor="#f0f0f0">
250<td valign="top">System settings
251<td valign="top">
252<a href="#desktopSettingsAware">desktopSettingsAware</a>(),
253<a href="#setDesktopSettingsAware">setDesktopSettingsAware</a>(),
254<a href="#cursorFlashTime">cursorFlashTime</a>(),
255<a href="#setCursorFlashTime">setCursorFlashTime</a>(),
256<a href="#doubleClickInterval">doubleClickInterval</a>(),
257<a href="#setDoubleClickInterval">setDoubleClickInterval</a>(),
258<a href="#wheelScrollLines">wheelScrollLines</a>(),
259<a href="#setWheelScrollLines">setWheelScrollLines</a>(),
260<a href="#palette">palette</a>(),
261<a href="#setPalette">setPalette</a>(),
262<a href="#font">font</a>(),
263<a href="#setFont">setFont</a>(),
264<a href="#fontMetrics">fontMetrics</a>().
265<tr bgcolor="#d0d0d0">
266<td valign="top">Event handling
267<td valign="top">
268<a href="#exec">exec</a>(),
269<a href="#processEvents">processEvents</a>(),
270<a href="#enter_loop">enter_loop</a>(),
271<a href="#exit_loop">exit_loop</a>(),
272<a href="#exit">exit</a>(),
273<a href="#quit">quit</a>().
274<a href="#sendEvent">sendEvent</a>(),
275<a href="#postEvent">postEvent</a>(),
276<a href="#sendPostedEvents">sendPostedEvents</a>(),
277<a href="#removePostedEvents">removePostedEvents</a>(),
278<a href="#hasPendingEvents">hasPendingEvents</a>(),
279<a href="#notify">notify</a>(),
280<a href="#macEventFilter">macEventFilter</a>(),
281<a href="#qwsEventFilter">qwsEventFilter</a>(),
282<a href="#x11EventFilter">x11EventFilter</a>(),
283<a href="#x11ProcessEvent">x11ProcessEvent</a>(),
284<a href="#winEventFilter">winEventFilter</a>().
285<tr bgcolor="#f0f0f0">
286<td valign="top">GUI Styles
287<td valign="top">
288<a href="#style">style</a>(),
289<a href="#setStyle">setStyle</a>(),
290<a href="#polish">polish</a>().
291<tr bgcolor="#d0d0d0">
292<td valign="top">Color usage
293<td valign="top">
294<a href="#colorSpec">colorSpec</a>(),
295<a href="#setColorSpec">setColorSpec</a>(),
296<a href="#qwsSetCustomColors">qwsSetCustomColors</a>().
297<tr bgcolor="#f0f0f0">
298<td valign="top">Text handling
299<td valign="top">
300<a href="#installTranslator">installTranslator</a>(),
301<a href="#removeTranslator">removeTranslator</a>()
302<a href="#translate">translate</a>().
303<tr bgcolor="#d0d0d0">
304<td valign="top">Widgets
305<td valign="top">
306<a href="#mainWidget">mainWidget</a>(),
307<a href="#setMainWidget">setMainWidget</a>(),
308<a href="#allWidgets">allWidgets</a>(),
309<a href="#topLevelWidgets">topLevelWidgets</a>(),
310<a href="#desktop">desktop</a>(),
311<a href="#activePopupWidget">activePopupWidget</a>(),
312<a href="#activeModalWidget">activeModalWidget</a>(),
313<a href="#clipboard">clipboard</a>(),
314<a href="#focusWidget">focusWidget</a>(),
315<a href="#winFocus">winFocus</a>(),
316<a href="#activeWindow">activeWindow</a>(),
317<a href="#widgetAt">widgetAt</a>().
318<tr bgcolor="#f0f0f0">
319<td valign="top">Advanced cursor handling
320<td valign="top">
321<a href="#hasGlobalMouseTracking">hasGlobalMouseTracking</a>(),
322<a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>(),
323<a href="#overrideCursor">overrideCursor</a>(),
324<a href="#setOverrideCursor">setOverrideCursor</a>(),
325<a href="#restoreOverrideCursor">restoreOverrideCursor</a>().
326<tr bgcolor="#d0d0d0">
327<td valign="top">X Window System synchronization
328<td valign="top">
329<a href="#flushX">flushX</a>(),
330<a href="#syncX">syncX</a>().
331<tr bgcolor="#f0f0f0">
332<td valign="top">Session management
333<td valign="top">
334<a href="#isSessionRestored">isSessionRestored</a>(),
335<a href="#sessionId">sessionId</a>(),
336<a href="#commitData">commitData</a>(),
337<a href="#saveState">saveState</a>().
338<tr bgcolor="#d0d0d0">
339<td valign="top">Threading
340<td valign="top">
341<a href="#lock">lock</a>(), <a href="#unlock">unlock</a>(), <a href="#locked">locked</a>(), <a href="#tryLock">tryLock</a>(),
342<a href="#wakeUpGuiThread">wakeUpGuiThread</a>()
343<tr bgcolor="#f0f0f0">
344<td valign="top">Miscellaneous
345<td valign="top">
346<a href="#closeAllWindows">closeAllWindows</a>(),
347<a href="#startingUp">startingUp</a>(),
348<a href="#closingDown">closingDown</a>(),
349<a href="#type">type</a>().
350</table></center>
351<p> <em>Non-GUI programs:</em> While Qt is not optimized or
352designed for writing non-GUI programs, it's possible to use
353<a href="tools.html">some of its classes</a> without creating a
354QApplication. This can be useful if you wish to share code between
355a non-GUI server and a GUI client.
356
357
358
359<p>See also <a href="application.html">Main Window and Related Classes</a>.
360
361<hr><h2>Member Type Documentation</h2>
362<h3 class=fn><a name="ColorSpec-enum"></a>QApplication::ColorSpec</h3>
363
364<ul>
365<li><tt>QApplication::NormalColor</tt> - the default color allocation policy
366<li><tt>QApplication::CustomColor</tt> - the same as NormalColor for X11; allocates colors
367to a palette on demand under Windows
368<li><tt>QApplication::ManyColor</tt> - the right choice for applications that use thousands of
369colors
370</ul><p> See <a href="#setColorSpec">setColorSpec</a>() for full details.
371
372<h3 class=fn><a name="Encoding-enum"></a>QApplication::Encoding</h3>
373<p> This enum type defines the 8-bit encoding of character string
374arguments to <a href="#translate">translate</a>():
375<ul>
376<li><tt>QApplication::DefaultCodec</tt> - the encoding specified by
377<a href="qtextcodec.html#codecForTr">QTextCodec::codecForTr</a>() (Latin-1 if none has been set)
378<li><tt>QApplication::UnicodeUTF8</tt> - UTF-8
379</ul><p> <p>See also <a href="qobject.html#tr">QObject::tr</a>(), <a href="qobject.html#trUtf8">QObject::trUtf8</a>(), and <a href="qstring.html#fromUtf8">QString::fromUtf8</a>().
380
381<h3 class=fn><a name="Type-enum"></a>QApplication::Type</h3>
382
383<ul>
384<li><tt>QApplication::Tty</tt> - a console application
385<li><tt>QApplication::GuiClient</tt> - a GUI client application
386<li><tt>QApplication::GuiServer</tt> - a GUI server application
387</ul>
388<hr><h2>Member Function Documentation</h2>
389<h3 class=fn><a name="QApplication"></a>QApplication::QApplication ( int&nbsp;&amp;&nbsp;argc, char&nbsp;**&nbsp;argv )
390</h3>
391Initializes the window system and constructs an application object
392with <em>argc</em> command line arguments in <em>argv</em>.
393<p> The global <tt>qApp</tt> pointer refers to this application object. Only
394one application object should be created.
395<p> This application object must be constructed before any <a href="qpaintdevice.html">paint devices</a> (including widgets, pixmaps, bitmaps
396etc.).
397<p> Note that <em>argc</em> and <em>argv</em> might be changed. Qt removes command
398line arguments that it recognizes. The modified <em>argc</em> and <em>argv</em>
399can also be accessed later with <tt>qApp-&gt;argc()</tt> and <tt>qApp-&gt;argv()</tt>.
400The documentation for <a href="#argv">argv</a>() contains a detailed description of how
401to process command line arguments.
402<p> Qt debugging options (not available if Qt was compiled with the
403QT_NO_DEBUG flag defined):
404<ul>
405<li> -nograb, tells Qt that it must never grab the mouse or the keyboard.
406<li> -dograb (only under X11), running under a debugger can cause
407an implicit -nograb, use -dograb to override.
408<li> -sync (only under X11), switches to synchronous mode for
409debugging.
410</ul>
411<p> See <a href="debug.html">Debugging Techniques</a> for a more
412detailed explanation.
413<p> All Qt programs automatically support the following command line options:
414<ul>
415<li> -reverse causes text to be formatted for right-to-left languages
416rather than in the usual left-to-right direction.
417<li> -style= <em>style</em>, sets the application GUI style. Possible values
418are <tt>motif</tt>, <tt>windows</tt>, and <tt>platinum</tt>. If you compiled Qt
419with additional styles or have additional styles as plugins these
420will be available to the <tt>-style</tt> command line option.
421<li> -style <em>style</em>, is the same as listed above.
422<li> -session= <em>session</em>, restores the application from an earlier
423<a href="session.html">session</a>.
424<li> -session <em>session</em>, is the same as listed above.
425<li> -widgetcount, prints debug message at the end about number of widgets left
426undestroyed and maximum number of widgets existed at the same time
427</ul>
428<p> The X11 version of Qt also supports some traditional X11
429command line options:
430<ul>
431<li> -display <em>display</em>, sets the X display (default is $DISPLAY).
432<li> -geometry <em>geometry</em>, sets the client geometry of the
433<a href="#setMainWidget">main widget</a>.
434<li> -fn or <tt>-font</tt> <em>font</em>, defines the application font. The
435font should be specified using an X logical font description.
436<li> -bg or <tt>-background</tt> <em>color</em>, sets the default background color
437and an application palette (light and dark shades are calculated).
438<li> -fg or <tt>-foreground</tt> <em>color</em>, sets the default foreground color.
439<li> -btn or <tt>-button</tt> <em>color</em>, sets the default button color.
440<li> -name <em>name</em>, sets the application name.
441<li> -title <em>title</em>, sets the application title (caption).
442<li> -visual <tt>TrueColor</tt>, forces the application to use a TrueColor visual
443on an 8-bit display.
444<li> -ncols <em>count</em>, limits the number of colors allocated in the
445color cube on an 8-bit display, if the application is using the
446<a href="#ColorSpec-enum">QApplication::ManyColor</a> color specification. If <em>count</em> is
447216 then a 6x6x6 color cube is used (i.e. 6 levels of red, 6 of green,
448and 6 of blue); for other values, a cube
449approximately proportional to a 2x3x1 cube is used.
450<li> -cmap, causes the application to install a private color map
451on an 8-bit display.
452</ul>
453<p> <p>See also <a href="#argc">argc</a>() and <a href="#argv">argv</a>().
454
455<h3 class=fn><a name="QApplication-2"></a>QApplication::QApplication ( int&nbsp;&amp;&nbsp;argc, char&nbsp;**&nbsp;argv, bool&nbsp;GUIenabled )
456</h3>
457Constructs an application object with <em>argc</em> command line arguments
458in <em>argv</em>. If <em>GUIenabled</em> is TRUE, a GUI application is
459constructed, otherwise a non-GUI (console) application is created.
460<p> Set <em>GUIenabled</em> to FALSE for programs without a graphical user
461interface that should be able to run without a window system.
462<p> On X11, the window system is initialized if <em>GUIenabled</em> is TRUE.
463If <em>GUIenabled</em> is FALSE, the application does not connect to the
464X-server.
465On Windows and Macintosh, currently the window system is always
466initialized, regardless of the value of GUIenabled. This may change in
467future versions of Qt.
468<p> The following example shows how to create an application that
469uses a graphical interface when available.
470<pre>
471 int main( int argc, char **argv )
472 {
473#ifdef Q_WS_X11
474 bool useGUI = getenv( "DISPLAY" ) != 0;
475#else
476 bool useGUI = TRUE;
477#endif
478 QApplication app(argc, argv, useGUI);
479
480 if ( useGUI ) {
481 //start GUI version
482 ...
483 } else {
484 //start non-GUI version
485 ...
486 }
487 return app.<a href="#exec">exec</a>();
488 }
489</pre>
490
491
492<h3 class=fn><a name="QApplication-3"></a>QApplication::QApplication ( int&nbsp;&amp;&nbsp;argc, char&nbsp;**&nbsp;argv, <a href="qapplication.html#Type-enum">Type</a>&nbsp;type )
493</h3>
494Constructs an application object with <em>argc</em> command line arguments
495in <em>argv</em>.
496<p> For Qt/Embedded, passing <a href="#Type-enum">QApplication::GuiServer</a> for <em>type</em>
497makes this application the server (equivalent to running with the
498-qws option).
499
500<h3 class=fn><a name="QApplication-4"></a>QApplication::QApplication ( Display&nbsp;*&nbsp;dpy, HANDLE&nbsp;visual = 0, HANDLE&nbsp;colormap = 0 )
501</h3>
502Create an application, given an already open display <em>dpy</em>. If <em>visual</em> and <em>colormap</em> are non-zero, the application will use those as
503the default Visual and Colormap contexts.
504<p> <b>Warning:</b> Qt only supports TrueColor visuals at depths higher than 8
505bits-per-pixel.
506<p> This is available only on X11.
507
508<h3 class=fn><a name="QApplication-5"></a>QApplication::QApplication ( Display&nbsp;*&nbsp;dpy, int&nbsp;argc, char&nbsp;**&nbsp;argv, HANDLE&nbsp;visual = 0, HANDLE&nbsp;colormap = 0 )
509</h3>
510Create an application, given an already open display <em>dpy</em> and using
511<em>argc</em> command line arguments in <em>argv</em>. If <em>visual</em> and <em>colormap</em> are non-zero, the application will use those as
512the default Visual and Colormap contexts.
513<p> <b>Warning:</b> Qt only supports TrueColor visuals at depths higher than 8
514bits-per-pixel.
515<p> This is available only on X11.
516<p>
517<h3 class=fn><a name="~QApplication"></a>QApplication::~QApplication ()<tt> [virtual]</tt>
518</h3>
519Cleans up any window system resources that were allocated by this
520application. Sets the global variable <tt>qApp</tt> to 0.
521
522<h3 class=fn>void <a name="aboutQt"></a>QApplication::aboutQt ()<tt> [slot]</tt>
523</h3>
524Displays a simple message box about Qt. The message includes the
525version number of Qt being used by the application.
526<p> This is useful for inclusion in the Help menu of an application.
527See the examples/menu/menu.cpp example.
528<p> This function is a convenience slot for <a href="qmessagebox.html#aboutQt">QMessageBox::aboutQt</a>().
529
530<h3 class=fn>void <a name="aboutToQuit"></a>QApplication::aboutToQuit ()<tt> [signal]</tt>
531</h3>
532
533<p> This signal is emitted when the application is about to quit the
534main event loop, e.g. when the event loop level drops to zero.
535This may happen either after a call to <a href="#quit">quit</a>() from inside the
536application or when the users shuts down the entire desktop session.
537<p> The signal is particularly useful if your application has to do some
538last-second cleanup. Note that no user interaction is possible in
539this state.
540<p> <p>See also <a href="#quit">quit</a>().
541
542<h3 class=fn><a href="qwidget.html">QWidget</a>&nbsp;* <a name="activeModalWidget"></a>QApplication::activeModalWidget ()<tt> [static]</tt>
543</h3>
544Returns the active modal widget.
545<p> A modal widget is a special top level widget which is a subclass of
546<a href="qdialog.html">QDialog</a> that specifies the modal parameter of the constructor as
547TRUE. A modal widget must be closed before the user can continue
548with other parts of the program.
549<p> Modal widgets are organized in a stack. This function returns
550the active modal widget at the top of the stack.
551<p> <p>See also <a href="#activePopupWidget">activePopupWidget</a>() and <a href="#topLevelWidgets">topLevelWidgets</a>().
552
553<h3 class=fn><a href="qwidget.html">QWidget</a>&nbsp;* <a name="activePopupWidget"></a>QApplication::activePopupWidget ()<tt> [static]</tt>
554</h3>
555Returns the active popup widget.
556<p> A popup widget is a special top level widget that sets the <a href="qt.html#WidgetFlags-enum">WType_Popup</a> widget flag, e.g. the <a href="qpopupmenu.html">QPopupMenu</a> widget. When the
557application opens a popup widget, all events are sent to the popup.
558Normal widgets and modal widgets cannot be accessed before the popup
559widget is closed.
560<p> Only other popup widgets may be opened when a popup widget is shown.
561The popup widgets are organized in a stack. This function returns
562the active popup widget at the top of the stack.
563<p> <p>See also <a href="#activeModalWidget">activeModalWidget</a>() and <a href="#topLevelWidgets">topLevelWidgets</a>().
564
565<h3 class=fn><a href="qwidget.html">QWidget</a>&nbsp;* <a name="activeWindow"></a>QApplication::activeWindow () const
566</h3>
567
568<p> Returns the application top-level window that has the keyboard input
569focus, or 0 if no application window has the focus. Note that
570there might be an <a href="#activeWindow">activeWindow</a>() even if there is no <a href="#focusWidget">focusWidget</a>(),
571for example if no widget in that window accepts key events.
572<p> <p>See also <a href="qwidget.html#setFocus">QWidget::setFocus</a>(), <a href="qwidget.html#focus-prop">QWidget::focus</a>, and <a href="#focusWidget">focusWidget</a>().
573
574<p>Example: <a href="mail-example.html#x704">network/mail/smtp.cpp</a>.
575<h3 class=fn>void <a name="addLibraryPath"></a>QApplication::addLibraryPath ( const&nbsp;<a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;path )<tt> [static]</tt>
576</h3>
577Append <em>path</em> to the end of the library path list. If <em>path</em> is
578empty or already in the path list, the path list is not changed.
579<p> The default path list consists of a single entry, the installation
580directory for plugins. The default installation directory for plugins
581is <tt>INSTALL/plugins</tt>, where <tt>INSTALL</tt> is the directory where Qt was
582installed.
583<p> <p>See also <a href="#removeLibraryPath">removeLibraryPath</a>(), <a href="#libraryPaths">libraryPaths</a>(), and <a href="#setLibraryPaths">setLibraryPaths</a>().
584
585<h3 class=fn>QWidgetList * <a name="allWidgets"></a>QApplication::allWidgets ()<tt> [static]</tt>
586</h3>
587Returns a list of all the widgets in the application.
588<p> The list is created using <tt>new</tt> and must be deleted by the caller.
589<p> The list is empty (<a href="qptrlist.html#isEmpty">QPtrList::isEmpty</a>()) if there are no widgets.
590<p> Note that some of the widgets may be hidden.
591<p> Example that updates all widgets:
592<pre>
593 QWidgetList *list = QApplication::<a href="#allWidgets">allWidgets</a>();
594 QWidgetListIt it( *list ); // iterate over the widgets
595 <a href="qwidget.html">QWidget</a> * w;
596 while ( (w=it.current()) != 0 ) { // for each widget...
597 ++it;
598 w-&gt;<a href="qwidget.html#update">update</a>();
599 }
600 delete list; // delete the list, not the widgets
601 </pre>
602
603<p> The QWidgetList class is defined in the <tt>qwidgetlist.h</tt> header
604file.
605<p> <b>Warning:</b> Delete the list as soon as you have finished using it.
606The widgets in the list may be deleted by someone else at any time.
607<p> <p>See also <a href="#topLevelWidgets">topLevelWidgets</a>(), <a href="qwidget.html#visible-prop">QWidget::visible</a>, and <a href="qptrlist.html#isEmpty">QPtrList::isEmpty</a>().
608
609<h3 class=fn><a href="qstring.html">QString</a> <a name="applicationDirPath"></a>QApplication::applicationDirPath ()
610</h3>
611Returns the directory that contains the application executable.
612<p> For example, if you have installed Qt in the <tt>C:&#92;Trolltech&#92;Qt</tt>
613directory, and you run the <tt>demo</tt> example, this function will
614return "C:/Trolltech/Qt/examples/demo".
615<p> On Mac OS X this will point to the directory actually containing the
616executable, which may be inside of an application bundle (if the
617application is bundled).
618<p> <b>Warning:</b> On Unix, this function assumes that argv[0] contains the file
619name of the executable (which it normally does). It also assumes that
620the current directory hasn't been changed by the application.
621<p> <p>See also <a href="#applicationFilePath">applicationFilePath</a>().
622
623<h3 class=fn><a href="qstring.html">QString</a> <a name="applicationFilePath"></a>QApplication::applicationFilePath ()
624</h3>
625Returns the file path of the application executable.
626<p> For example, if you have installed Qt in the <tt>C:&#92;Trolltech&#92;Qt</tt>
627directory, and you run the <tt>demo</tt> example, this function will
628return "C:/Trolltech/Qt/examples/demo/demo.exe".
629<p> <b>Warning:</b> On Unix, this function assumes that argv[0] contains the file
630name of the executable (which it normally does). It also assumes that
631the current directory hasn't been changed by the application.
632<p> <p>See also <a href="#applicationDirPath">applicationDirPath</a>().
633
634<h3 class=fn>int <a name="argc"></a>QApplication::argc () const
635</h3>
636
637<p> Returns the number of command line arguments.
638<p> The documentation for <a href="#argv">argv</a>() describes how to process command line
639arguments.
640<p> <p>See also <a href="#argv">argv</a>() and <a href="#QApplication">QApplication::QApplication</a>().
641
642<p>Examples: <a href="tutorial2-04.html#x2557">chart/main.cpp</a> and <a href="scribble-example.html#x906">scribble/scribble.cpp</a>.
643<h3 class=fn>char ** <a name="argv"></a>QApplication::argv () const
644</h3>
645
646<p> Returns the command line argument vector.
647<p> <tt>argv()[0]</tt> is the program name, <tt>argv()[1]</tt> is the first
648argument and <tt>argv()[argc()-1]</tt> is the last argument.
649<p> A QApplication object is constructed by passing <em>argc</em> and <em>argv</em> from the <tt>main()</tt> function. Some of the arguments may be
650recognized as Qt options and removed from the argument vector. For
651example, the X11 version of Qt knows about <tt>-display</tt>, <tt>-font</tt>
652and a few more options.
653<p> Example:
654<pre>
655 // showargs.cpp - displays program arguments in a list box
656
657 #include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;
658 #include &lt;<a href="qlistbox-h.html">qlistbox.h</a>&gt;
659
660 int main( int argc, char **argv )
661 {
662 QApplication a( argc, argv );
663 <a href="qlistbox.html">QListBox</a> b;
664 a.<a href="#setMainWidget">setMainWidget</a>( &amp;b );
665 for ( int i = 0; i &lt; a.<a href="#argc">argc</a>(); i++ ) // a.<a href="#argc">argc</a>() == argc
666 b.<a href="qlistbox.html#insertItem">insertItem</a>( a.<a href="#argv">argv</a>()[i] ); // a.<a href="#argv">argv</a>()[i] == argv[i]
667 b.<a href="qwidget.html#show">show</a>();
668 return a.<a href="#exec">exec</a>();
669 }
670 </pre>
671
672<p> If you run <tt>showargs -display unix:0 -font 9x15bold hello world</tt>
673under X11, the list box contains the three strings "showargs",
674"hello" and "world".
675<p> Qt provides a global pointer, <tt>qApp</tt>, that points to the
676QApplication object, and through which you can access <a href="#argc">argc</a>() and
677<a href="#argv">argv</a>() in functions other than main().
678<p> <p>See also <a href="#argc">argc</a>() and <a href="#QApplication">QApplication::QApplication</a>().
679
680<p>Examples: <a href="tutorial2-04.html#x2558">chart/main.cpp</a> and <a href="scribble-example.html#x907">scribble/scribble.cpp</a>.
681<h3 class=fn>void <a name="beep"></a>QApplication::beep ()<tt> [static]</tt>
682</h3>
683Sounds the bell, using the default volume and sound.
684
685<h3 class=fn><a href="qclipboard.html">QClipboard</a>&nbsp;* <a name="clipboard"></a>QApplication::clipboard ()<tt> [static]</tt>
686</h3>
687Returns a pointer to the application global clipboard.
688
689<p>Examples: <a href="regexptester-example.html#x2468">regexptester/regexptester.cpp</a> and <a href="showimg-example.html#x1308">showimg/showimg.cpp</a>.
690<h3 class=fn>void <a name="closeAllWindows"></a>QApplication::closeAllWindows ()<tt> [slot]</tt>
691</h3>
692Closes all top-level windows.
693<p> This function is particularly useful for applications with many
694top-level windows. It could, for example, be connected to a "Quit"
695entry in the file menu as shown in the following code example:
696<p> <pre>
697 // the "Quit" menu entry should try to close all windows
698 <a href="qpopupmenu.html">QPopupMenu</a>* file = new <a href="qpopupmenu.html">QPopupMenu</a>( this );
699 file-&gt;<a href="qmenudata.html#insertItem">insertItem</a>( "&amp;Quit", qApp, SLOT(<a href="#closeAllWindows">closeAllWindows</a>()), CTRL+Key_Q );
700
701 // when the last window is closed, the application should quit
702 <a href="qobject.html#connect">connect</a>( qApp, SIGNAL( <a href="#lastWindowClosed">lastWindowClosed</a>() ), qApp, SLOT( <a href="#quit">quit</a>() ) );
703 </pre>
704
705<p> The windows are closed in random order, until one window does not
706accept the close event.
707<p> <p>See also <a href="qwidget.html#close">QWidget::close</a>(), <a href="qwidget.html#closeEvent">QWidget::closeEvent</a>(), <a href="#lastWindowClosed">lastWindowClosed</a>(), <a href="#quit">quit</a>(), <a href="#topLevelWidgets">topLevelWidgets</a>(), and <a href="qwidget.html#isTopLevel-prop">QWidget::isTopLevel</a>.
708
709<p>
710<p>Examples: <a href="qaction-application-example.html#x1127">action/application.cpp</a>, <a href="simple-application-example.html#x1544">application/application.cpp</a>, <a href="helpviewer-example.html#x980">helpviewer/helpwindow.cpp</a>, <a href="mdi-example.html#x2020">mdi/application.cpp</a>, and <a href="qwerty-example.html#x358">qwerty/qwerty.cpp</a>.
711<h3 class=fn>bool <a name="closingDown"></a>QApplication::closingDown ()<tt> [static]</tt>
712</h3>
713Returns TRUE if the application objects are being destroyed;
714otherwise returns FALSE.
715<p> <p>See also <a href="#startingUp">startingUp</a>().
716
717<h3 class=fn>int <a name="colorSpec"></a>QApplication::colorSpec ()<tt> [static]</tt>
718</h3>
719Returns the color specification.
720<p>See also <a href="#setColorSpec">QApplication::setColorSpec</a>().
721
722<p>Example: <a href="showimg-example.html#x1309">showimg/showimg.cpp</a>.
723<h3 class=fn>void <a name="commitData"></a>QApplication::commitData ( <a href="qsessionmanager.html">QSessionManager</a>&nbsp;&amp;&nbsp;sm )<tt> [virtual]</tt>
724</h3>
725
726<p> This function deals with <a href="session.html">session
727 management</a>. It is invoked when the <a href="qsessionmanager.html">QSessionManager</a> wants the
728application to commit all its data.
729<p> Usually this means saving all open files, after getting
730permission from the user. Furthermore you may want to provide a means
731by which the user can cancel the shutdown.
732<p> Note that you should not exit the application within this function.
733Instead, the session manager may or may not do this afterwards,
734depending on the context.
735<p> <b>Warning:</b> Within this function, no user interaction is possible, <em>unless</em> you ask the session manager <em>sm</em> for explicit permission.
736See <a href="qsessionmanager.html#allowsInteraction">QSessionManager::allowsInteraction</a>() and
737<a href="qsessionmanager.html#allowsErrorInteraction">QSessionManager::allowsErrorInteraction</a>() for details and example
738usage.
739<p> The default implementation requests interaction and sends a close
740event to all visible top level widgets. If any event was
741rejected, the shutdown is canceled.
742<p> <p>See also <a href="#isSessionRestored">isSessionRestored</a>(), <a href="#sessionId">sessionId</a>(), <a href="#saveState">saveState</a>(), and <a href="session.html">the Session Management overview</a>.
743
744<h3 class=fn>int <a name="cursorFlashTime"></a>QApplication::cursorFlashTime ()<tt> [static]</tt>
745</h3>
746Returns the text cursor's flash (blink) time in milliseconds. The
747flash time is the time required to display, invert and restore the
748caret display.
749<p> The default value on X11 is 1000 milliseconds. On Windows, the
750control panel value is used.
751<p> Widgets should not cache this value since it may be changed at any
752time by the user changing the global desktop settings.
753<p> <p>See also <a href="#setCursorFlashTime">setCursorFlashTime</a>().
754
755<h3 class=fn><a href="qtextcodec.html">QTextCodec</a>&nbsp;* <a name="defaultCodec"></a>QApplication::defaultCodec () const
756</h3> <b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
757<p> Returns <a href="qtextcodec.html#codecForTr">QTextCodec::codecForTr</a>().
758
759<h3 class=fn><a href="qdesktopwidget.html">QDesktopWidget</a>&nbsp;* <a name="desktop"></a>QApplication::desktop ()<tt> [static]</tt>
760</h3>
761Returns the desktop widget (also called the root window).
762<p> The desktop widget is useful for obtaining the size of the screen.
763It may also be possible to draw on the desktop. We recommend against
764assuming that it's possible to draw on the desktop, since this does
765not work on all operating systems.
766<p> <pre>
767 <a href="qdesktopwidget.html">QDesktopWidget</a> *d = QApplication::<a href="#desktop">desktop</a>();
768 int w = d-&gt;<a href="qwidget.html#width">width</a>(); // returns desktop width
769 int h = d-&gt;<a href="qwidget.html#height">height</a>(); // returns desktop height
770 </pre>
771
772
773<p>Examples: <a href="canvas-example.html#x2958">canvas/main.cpp</a>, <a href="desktop-example.html#x1721">desktop/desktop.cpp</a>, <a href="helpviewer-example.html#x1037">helpviewer/main.cpp</a>, <a href="i18n-example.html#x1928">i18n/main.cpp</a>, <a href="qmag-example.html#x1765">qmag/qmag.cpp</a>, <a href="qwerty-example.html#x414">qwerty/main.cpp</a>, and <a href="scribble-example.html#x954">scribble/main.cpp</a>.
774<h3 class=fn>bool <a name="desktopSettingsAware"></a>QApplication::desktopSettingsAware ()<tt> [static]</tt>
775</h3>
776Returns the value set by <a href="#setDesktopSettingsAware">setDesktopSettingsAware</a>(); by default TRUE.
777<p> <p>See also <a href="#setDesktopSettingsAware">setDesktopSettingsAware</a>().
778
779<h3 class=fn>int <a name="doubleClickInterval"></a>QApplication::doubleClickInterval ()<tt> [static]</tt>
780</h3>
781Returns the maximum duration for a double click.
782<p> The default value on X11 is 400 milliseconds. On Windows, the
783control panel value is used.
784<p> <p>See also <a href="#setDoubleClickInterval">setDoubleClickInterval</a>().
785
786<h3 class=fn>int <a name="enter_loop"></a>QApplication::enter_loop ()
787</h3>
788<b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
789<p> This function enters the main event loop (recursively). Do not call
790it unless you really know what you are doing.
791<p> Use <a href="#eventLoop">QApplication::eventLoop</a>()->enterLoop() instead.
792<p>
793<h3 class=fn><a href="qeventloop.html">QEventLoop</a>&nbsp;* <a name="eventLoop"></a>QApplication::eventLoop ()<tt> [static]</tt>
794</h3>
795Returns the application event loop. This function will return
796zero if called during and after destroying QApplication.
797<p> To create your own instance of <a href="qeventloop.html">QEventLoop</a> or QEventLoop subclass create
798it before you create the QApplication object.
799<p> <p>See also <a href="qeventloop.html">QEventLoop</a>.
800
801<p>Example: <a href="distributor-example.html#x2651">distributor/distributor.ui.h</a>.
802<h3 class=fn>int <a name="exec"></a>QApplication::exec ()
803</h3>
804Enters the main event loop and waits until <a href="#exit">exit</a>() is called or the
805main widget is destroyed, and returns the value that was set to
806exit() (which is 0 if exit() is called via <a href="#quit">quit</a>()).
807<p> It is necessary to call this function to start event handling. The
808main event loop receives events from the window system and
809dispatches these to the application widgets.
810<p> Generally speaking, no user interaction can take place before
811calling <a href="#exec">exec</a>(). As a special case, modal widgets like <a href="qmessagebox.html">QMessageBox</a>
812can be used before calling exec(), because modal widgets call
813exec() to start a local event loop.
814<p> To make your application perform idle processing, i.e. executing a
815special function whenever there are no pending events, use a
816<a href="qtimer.html">QTimer</a> with 0 timeout. More advanced idle processing schemes can
817be achieved using <a href="#processEvents">processEvents</a>().
818<p> <p>See also <a href="#quit">quit</a>(), <a href="#exit">exit</a>(), <a href="#processEvents">processEvents</a>(), and <a href="#setMainWidget">setMainWidget</a>().
819
820<p>Examples: <a href="helpsystem-example.html#x2700">helpsystem/main.cpp</a>, <a href="qdialog.html#x2132">life/main.cpp</a>, <a href="archivesearch-example.html#x486">network/archivesearch/main.cpp</a>, <a href="ftpclient-example.html#x777">network/ftpclient/main.cpp</a>, <a href="qaxserver-example-opengl.html#x2731">opengl/main.cpp</a>, <a href="tutorial1-01.html#x2283">t1/main.cpp</a>, and <a href="tutorial1-04.html#x2303">t4/main.cpp</a>.
821<h3 class=fn>void <a name="exit"></a>QApplication::exit ( int&nbsp;retcode = 0 )<tt> [static]</tt>
822</h3>
823Tells the application to exit with a return code.
824<p> After this function has been called, the application leaves the main
825event loop and returns from the call to <a href="#exec">exec</a>(). The exec() function
826returns <em>retcode</em>.
827<p> By convention, a <em>retcode</em> of 0 means success, and any non-zero
828value indicates an error.
829<p> Note that unlike the C library function of the same name, this
830function <em>does</em> return to the caller -- it is event processing that
831stops.
832<p> <p>See also <a href="#quit">quit</a>() and <a href="#exec">exec</a>().
833
834<p>Examples: <a href="canvas-chart-example.html#x2875">chart/chartform.cpp</a>, <a href="extension-dialog-example.html#x2865">extension/mainform.ui.h</a>, and <a href="picture-example.html#x106">picture/picture.cpp</a>.
835<h3 class=fn>void <a name="exit_loop"></a>QApplication::exit_loop ()
836</h3>
837<b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
838<p> This function exits from a recursive call to the main event loop.
839Do not call it unless you are an expert.
840<p> Use <a href="#eventLoop">QApplication::eventLoop</a>()->exitLoop() instead.
841<p>
842<h3 class=fn>void <a name="flush"></a>QApplication::flush ()<tt> [static]</tt>
843</h3>
844Flushes the window system specific event queues.
845<p> If you are doing graphical changes inside a loop that does not
846return to the event loop on asynchronous window systems like X11
847or double buffered window systems like MacOS X, and you want to
848visualize these changes immediately (e.g. Splash Screens), call
849this function.
850<p> <p>See also <a href="#flushX">flushX</a>(), <a href="#sendPostedEvents">sendPostedEvents</a>(), and <a href="qpainter.html#flush">QPainter::flush</a>().
851
852<h3 class=fn>void <a name="flushX"></a>QApplication::flushX ()<tt> [static]</tt>
853</h3>
854Flushes the X event queue in the X11 implementation. This normally
855returns almost immediately. Does nothing on other platforms.
856<p> <p>See also <a href="#syncX">syncX</a>().
857
858<p>Example: <a href="xform-example.html#x1217">xform/xform.cpp</a>.
859<h3 class=fn><a href="qwidget.html">QWidget</a>&nbsp;* <a name="focusWidget"></a>QApplication::focusWidget () const
860</h3>
861
862<p> Returns the application widget that has the keyboard input focus, or
8630 if no widget in this application has the focus.
864<p> <p>See also <a href="qwidget.html#setFocus">QWidget::setFocus</a>(), <a href="qwidget.html#focus-prop">QWidget::focus</a>, and <a href="#activeWindow">activeWindow</a>().
865
866<h3 class=fn><a href="qfont.html">QFont</a> <a name="font"></a>QApplication::font ( const&nbsp;<a href="qwidget.html">QWidget</a>&nbsp;*&nbsp;w = 0 )<tt> [static]</tt>
867</h3>
868Returns the default font for the widget <em>w</em>, or the default
869application font if <em>w</em> is 0.
870<p> <p>See also <a href="#setFont">setFont</a>(), <a href="#fontMetrics">fontMetrics</a>(), and <a href="qwidget.html#font-prop">QWidget::font</a>.
871
872<p>Examples: <a href="qfd-example.html#x1979">qfd/fontdisplayer.cpp</a>, <a href="themes-example.html#x264">themes/metal.cpp</a>, and <a href="themes-example.html#x321">themes/themes.cpp</a>.
873<h3 class=fn><a href="qfontmetrics.html">QFontMetrics</a> <a name="fontMetrics"></a>QApplication::fontMetrics ()<tt> [static]</tt>
874</h3>
875Returns display (screen) font metrics for the application font.
876<p> <p>See also <a href="#font">font</a>(), <a href="#setFont">setFont</a>(), <a href="qwidget.html#fontMetrics">QWidget::fontMetrics</a>(), and <a href="qpainter.html#fontMetrics">QPainter::fontMetrics</a>().
877
878<h3 class=fn><a href="qsize.html">QSize</a> <a name="globalStrut"></a>QApplication::globalStrut ()<tt> [static]</tt>
879</h3>
880
881<p> Returns the application's global strut.
882<p> The strut is a size object whose dimensions are the minimum that any
883GUI element that the user can interact with should have. For example
884no button should be resized to be smaller than the global strut size.
885<p> <p>See also <a href="#setGlobalStrut">setGlobalStrut</a>().
886
887<h3 class=fn>void <a name="guiThreadAwake"></a>QApplication::guiThreadAwake ()<tt> [signal]</tt>
888</h3>
889
890<p> This signal is emitted after the event loop returns from a function
891that could block.
892<p> <p>See also <a href="#wakeUpGuiThread">wakeUpGuiThread</a>().
893
894<h3 class=fn>bool <a name="hasGlobalMouseTracking"></a>QApplication::hasGlobalMouseTracking ()<tt> [static]</tt>
895</h3>
896
897<p> Returns TRUE if global mouse tracking is enabled; otherwise
898returns FALSE.
899<p> <p>See also <a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>().
900
901<h3 class=fn>bool <a name="hasPendingEvents"></a>QApplication::hasPendingEvents ()
902</h3>
903This function returns TRUE if there are pending events; otherwise
904returns FALSE. Pending events can be either from the window system
905or posted events using <a href="#postEvent">QApplication::postEvent</a>().
906
907<h3 class=fn>int <a name="horizontalAlignment"></a>QApplication::horizontalAlignment ( int&nbsp;align )<tt> [static]</tt>
908</h3>
909
910<p> Strips out vertical alignment flags and transforms an
911alignment <em>align</em> of AlignAuto into AlignLeft or
912AlignRight according to the language used. The other horizontal
913alignment flags are left untouched.
914
915<h3 class=fn>void <a name="installTranslator"></a>QApplication::installTranslator ( <a href="qtranslator.html">QTranslator</a>&nbsp;*&nbsp;mf )
916</h3>
917Adds the message file <em>mf</em> to the list of message files to be used
918for translations.
919<p> Multiple message files can be installed. Translations are searched
920for in the last installed message file, then the one from last, and
921so on, back to the first installed message file. The search stops as
922soon as a matching translation is found.
923<p> <p>See also <a href="#removeTranslator">removeTranslator</a>(), <a href="#translate">translate</a>(), and <a href="qtranslator.html#load">QTranslator::load</a>().
924
925<p>Example: <a href="i18n-example.html#x1930">i18n/main.cpp</a>.
926<h3 class=fn>bool <a name="isEffectEnabled"></a>QApplication::isEffectEnabled ( <a href="qt.html#UIEffect-enum">Qt::UIEffect</a>&nbsp;effect )<tt> [static]</tt>
927</h3>
928Returns TRUE if <em>effect</em> is enabled; otherwise returns FALSE.
929<p> By default, Qt will try to use the desktop settings. Call
930<a href="#setDesktopSettingsAware">setDesktopSettingsAware</a>(FALSE) to prevent this.
931<p> Note: All effects are disabled on screens running at less than
93216-bit color depth.
933<p> <p>See also <a href="#setEffectEnabled">setEffectEnabled</a>() and <a href="qt.html#UIEffect-enum">Qt::UIEffect</a>.
934
935<h3 class=fn>bool <a name="isSessionRestored"></a>QApplication::isSessionRestored () const
936</h3>
937
938<p> Returns TRUE if the application has been restored from an earlier
939<a href="session.html">session</a>; otherwise returns FALSE.
940<p> <p>See also <a href="#sessionId">sessionId</a>(), <a href="#commitData">commitData</a>(), and <a href="#saveState">saveState</a>().
941
942<h3 class=fn>void <a name="lastWindowClosed"></a>QApplication::lastWindowClosed ()<tt> [signal]</tt>
943</h3>
944
945<p> This signal is emitted when the user has closed the last
946top level window.
947<p> The signal is very useful when your application has many top level
948widgets but no main widget. You can then connect it to the <a href="#quit">quit</a>()
949slot.
950<p> For convenience, this signal is <em>not</em> emitted for transient top level
951widgets such as popup menus and dialogs.
952<p> <p>See also <a href="#mainWidget">mainWidget</a>(), <a href="#topLevelWidgets">topLevelWidgets</a>(), <a href="qwidget.html#isTopLevel-prop">QWidget::isTopLevel</a>, and <a href="qwidget.html#close">QWidget::close</a>().
953
954<p>Examples: <a href="addressbook-example.html#x608">addressbook/main.cpp</a>, <a href="extension-dialog-example.html#x2867">extension/main.cpp</a>, <a href="helpviewer-example.html#x1039">helpviewer/main.cpp</a>, <a href="mdi-example.html#x2096">mdi/main.cpp</a>, <a href="archivesearch-example.html#x487">network/archivesearch/main.cpp</a>, <a href="qwerty-example.html#x416">qwerty/main.cpp</a>, and <a href="regexptester-example.html#x2509">regexptester/main.cpp</a>.
955<h3 class=fn><a href="qstringlist.html">QStringList</a> <a name="libraryPaths"></a>QApplication::libraryPaths ()<tt> [static]</tt>
956</h3>
957Returns a list of paths that the application will search when
958dynamically loading libraries.
959The installation directory for plugins is the only entry if no
960paths have been set. The default installation directory for plugins
961is <tt>INSTALL/plugins</tt>, where <tt>INSTALL</tt> is the directory where Qt was
962installed. The directory of the application executable (NOT the
963working directory) is also added to the plugin paths.
964<p> If you want to iterate over the list, you should iterate over a
965copy, e.g.
966<pre>
967 <a href="qstringlist.html">QStringList</a> list = app.libraryPaths();
968 QStringList::Iterator it = list.<a href="qvaluelist.html#begin">begin</a>();
969 while( it != list.<a href="qvaluelist.html#end">end</a>() ) {
970 myProcessing( *it );
971 ++it;
972 }
973 </pre>
974
975<p> See the <a href="plugins-howto.html">plugins documentation</a> for a
976description of how the library paths are used.
977<p> <p>See also <a href="#setLibraryPaths">setLibraryPaths</a>(), <a href="#addLibraryPath">addLibraryPath</a>(), <a href="#removeLibraryPath">removeLibraryPath</a>(), and <a href="qlibrary.html">QLibrary</a>.
978
979<h3 class=fn>void <a name="lock"></a>QApplication::lock ()
980</h3>
981<p> Lock the Qt Library Mutex. If another thread has already locked the
982mutex, the calling thread will block until the other thread has
983unlocked the mutex.
984<p> <p>See also <a href="#unlock">unlock</a>(), <a href="#locked">locked</a>(), and <a href="threads.html">Thread Support in Qt</a>.
985
986<h3 class=fn>bool <a name="locked"></a>QApplication::locked ()
987</h3>
988<p> Returns TRUE if the Qt Library Mutex is locked by a different thread;
989otherwise returns FALSE.
990<p> <b>Warning:</b> Due to different implementations of recursive mutexes on
991the supported platforms, calling this function from the same thread
992that previously locked the mutex will give undefined results.
993<p> <p>See also <a href="#lock">lock</a>(), <a href="#unlock">unlock</a>(), and <a href="threads.html">Thread Support in Qt</a>.
994
995<h3 class=fn>int <a name="loopLevel"></a>QApplication::loopLevel () const
996</h3>
997<b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
998<p> Returns the current loop level.
999<p> Use <a href="#eventLoop">QApplication::eventLoop</a>()->loopLevel() instead.
1000<p>
1001<h3 class=fn>bool <a name="macEventFilter"></a>QApplication::macEventFilter ( EventHandlerCallRef, EventRef )<tt> [virtual]</tt>
1002</h3>
1003This virtual function is only implemented under Macintosh.
1004<p> If you create an application that inherits QApplication and
1005reimplement this function, you get direct access to all Carbon Events
1006that are received from the MacOS.
1007<p> Return TRUE if you want to stop the event from being processed.
1008Return FALSE for normal event dispatching.
1009
1010<h3 class=fn><a href="qwidget.html">QWidget</a>&nbsp;* <a name="mainWidget"></a>QApplication::mainWidget () const
1011</h3>
1012
1013<p> Returns the main application widget, or 0 if there is no main
1014widget.
1015<p> <p>See also <a href="#setMainWidget">setMainWidget</a>().
1016
1017<h3 class=fn>bool <a name="notify"></a>QApplication::notify ( <a href="qobject.html">QObject</a>&nbsp;*&nbsp;receiver, <a href="qevent.html">QEvent</a>&nbsp;*&nbsp;e )<tt> [virtual]</tt>
1018</h3>
1019Sends event <em>e</em> to <em>receiver</em>: <em>receiver</em>->event(<em>e</em>).
1020Returns the value that is returned from the receiver's event handler.
1021<p> For certain types of events (e.g. mouse and key events),
1022the event will be propagated to the receiver's parent and so on up to
1023the top-level object if the receiver is not interested in the event
1024(i.e., it returns FALSE).
1025<p> There are five different ways that events can be processed;
1026reimplementing this virtual function is just one of them. All five
1027approaches are listed below:
1028<ol type=1>
1029<li> Reimplementing this function. This is very powerful, providing
1030complete control; but only one subclass can be qApp.
1031<p> <li> Installing an event filter on qApp. Such an event filter is able
1032to process all events for all widgets, so it's just as powerful as
1033reimplementing <a href="#notify">notify</a>(); furthermore, it's possible to have more
1034than one application-global event filter. Global event filters even
1035see mouse events for <a href="qwidget.html#isEnabled">disabled
1036 widgets,</a> and if <a href="#setGlobalMouseTracking">global mouse
1037 tracking</a> is enabled, as well as mouse move events for all
1038widgets.
1039<p> <li> Reimplementing <a href="qobject.html#event">QObject::event</a>() (as <a href="qwidget.html">QWidget</a> does). If you do
1040this you get Tab key presses, and you get to see the events before
1041any widget-specific event filters.
1042<p> <li> Installing an event filter on the object. Such an event filter
1043gets all the events except Tab and Shift-Tab key presses.
1044<p> <li> Reimplementing paintEvent(), mousePressEvent() and so
1045on. This is the commonest, easiest and least powerful way.
1046</ol>
1047<p> <p>See also <a href="qobject.html#event">QObject::event</a>() and <a href="qobject.html#installEventFilter">installEventFilter</a>().
1048
1049<h3 class=fn><a href="qcursor.html">QCursor</a>&nbsp;* <a name="overrideCursor"></a>QApplication::overrideCursor ()<tt> [static]</tt>
1050</h3>
1051
1052<p> Returns the active application override cursor.
1053<p> This function returns 0 if no application cursor has been defined
1054(i.e. the internal cursor stack is empty).
1055<p> <p>See also <a href="#setOverrideCursor">setOverrideCursor</a>() and <a href="#restoreOverrideCursor">restoreOverrideCursor</a>().
1056
1057<h3 class=fn><a href="qpalette.html">QPalette</a> <a name="palette"></a>QApplication::palette ( const&nbsp;<a href="qwidget.html">QWidget</a>&nbsp;*&nbsp;w = 0 )<tt> [static]</tt>
1058</h3>
1059Returns the application palette.
1060<p> If a widget is passed in <em>w</em>, the default palette for the
1061widget's class is returned. This may or may not be the application
1062palette. In most cases there isn't a special palette for certain
1063types of widgets, but one notable exception is the popup menu under
1064Windows, if the user has defined a special background color for
1065menus in the display settings.
1066<p> <p>See also <a href="#setPalette">setPalette</a>() and <a href="qwidget.html#palette-prop">QWidget::palette</a>.
1067
1068<p>Examples: <a href="desktop-example.html#x1723">desktop/desktop.cpp</a>, <a href="themes-example.html#x265">themes/metal.cpp</a>, and <a href="themes-example.html#x186">themes/wood.cpp</a>.
1069<h3 class=fn>void <a name="polish"></a>QApplication::polish ( <a href="qwidget.html">QWidget</a>&nbsp;*&nbsp;w )<tt> [virtual]</tt>
1070</h3>
1071Initialization of the appearance of the widget <em>w</em> <em>before</em> it is first
1072shown.
1073<p> Usually widgets call this automatically when they are polished. It
1074may be used to do some style-based central customization of widgets.
1075<p> Note that you are not limited to the public functions of <a href="qwidget.html">QWidget</a>.
1076Instead, based on meta information like <a href="qobject.html#className">QObject::className</a>() you are
1077able to customize any kind of widget.
1078<p> <p>See also <a href="qstyle.html#polish">QStyle::polish</a>(), <a href="qwidget.html#polish">QWidget::polish</a>(), <a href="#setPalette">setPalette</a>(), and <a href="#setFont">setFont</a>().
1079
1080<h3 class=fn>void <a name="postEvent"></a>QApplication::postEvent ( <a href="qobject.html">QObject</a>&nbsp;*&nbsp;receiver, <a href="qevent.html">QEvent</a>&nbsp;*&nbsp;event )<tt> [static]</tt>
1081</h3><p><b>Note:</b> This function is <a href="threads.html#threadsafe">thread-safe</a> when Qt is built withthread support.</p>
1082
1083Adds the event <em>event</em> with the object <em>receiver</em> as the receiver of the
1084event, to an event queue and returns immediately.
1085<p> The event must be allocated on the heap since the post event queue
1086will take ownership of the event and delete it once it has been posted.
1087<p> When control returns to the main event loop, all events that are
1088stored in the queue will be sent using the <a href="#notify">notify</a>() function.
1089<p>
1090<p> <p>See also <a href="#sendEvent">sendEvent</a>() and <a href="#notify">notify</a>().
1091
1092<h3 class=fn>void <a name="processEvents"></a>QApplication::processEvents ()
1093</h3>
1094Processes pending events, for 3 seconds or until there are no more
1095events to process, whichever is shorter.
1096<p> You can call this function occasionally when your program is busy
1097performing a long operation (e.g. copying a file).
1098<p> <p>See also <a href="#exec">exec</a>(), <a href="qtimer.html">QTimer</a>, and <a href="qeventloop.html#processEvents">QEventLoop::processEvents</a>().
1099
1100<p>Examples: <a href="fileiconview-example.html#x808">fileiconview/qfileiconview.cpp</a> and <a href="ftpclient-example.html#x778">network/ftpclient/main.cpp</a>.
1101<h3 class=fn>void <a name="processEvents-2"></a>QApplication::processEvents ( int&nbsp;maxtime )
1102</h3>
1103This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
1104<p> Processes pending events for <em>maxtime</em> milliseconds or until
1105there are no more events to process, whichever is shorter.
1106<p> You can call this function occasionally when you program is busy
1107doing a long operation (e.g. copying a file).
1108<p> <p>See also <a href="#exec">exec</a>(), <a href="qtimer.html">QTimer</a>, and <a href="qeventloop.html#processEvents">QEventLoop::processEvents</a>().
1109
1110<h3 class=fn>void <a name="processOneEvent"></a>QApplication::processOneEvent ()
1111</h3> <b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
1112<p> Waits for an event to occur, processes it, then returns.
1113<p> This function is useful for adapting Qt to situations where the
1114event processing must be grafted onto existing program loops.
1115<p> Using this function in new applications may be an indication of design
1116problems.
1117<p> <p>See also <a href="#processEvents">processEvents</a>(), <a href="#exec">exec</a>(), and <a href="qtimer.html">QTimer</a>.
1118
1119<h3 class=fn>void <a name="quit"></a>QApplication::quit ()<tt> [slot]</tt>
1120</h3>
1121Tells the application to exit with return code 0 (success).
1122Equivalent to calling <a href="#exit">QApplication::exit</a>( 0 ).
1123<p> It's common to connect the <a href="#lastWindowClosed">lastWindowClosed</a>() signal to <a href="#quit">quit</a>(), and
1124you also often connect e.g. <a href="qbutton.html#clicked">QButton::clicked</a>() or signals in
1125<a href="qaction.html">QAction</a>, <a href="qpopupmenu.html">QPopupMenu</a> or <a href="qmenubar.html">QMenuBar</a> to it.
1126<p> Example:
1127<pre>
1128 <a href="qpushbutton.html">QPushButton</a> *quitButton = new <a href="qpushbutton.html">QPushButton</a>( "Quit" );
1129 <a href="qobject.html#connect">connect</a>( quitButton, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), qApp, SLOT(<a href="#quit">quit</a>()) );
1130 </pre>
1131
1132<p> <p>See also <a href="#exit">exit</a>(), <a href="#aboutToQuit">aboutToQuit</a>(), <a href="#lastWindowClosed">lastWindowClosed</a>(), and <a href="qaction.html">QAction</a>.
1133
1134<p>Examples: <a href="addressbook-example.html#x609">addressbook/main.cpp</a>, <a href="mdi-example.html#x2097">mdi/main.cpp</a>, <a href="archivesearch-example.html#x488">network/archivesearch/main.cpp</a>, <a href="regexptester-example.html#x2510">regexptester/main.cpp</a>, <a href="tutorial1-02.html#x2288">t2/main.cpp</a>, <a href="tutorial1-04.html#x2304">t4/main.cpp</a>, and <a href="tutorial1-06.html#x2321">t6/main.cpp</a>.
1135<h3 class=fn><a href="qwsdecoration.html">QWSDecoration</a>&nbsp;&amp; <a name="qwsDecoration"></a>QApplication::qwsDecoration ()<tt> [static]</tt>
1136</h3>
1137Return the <a href="qwsdecoration.html">QWSDecoration</a> used for decorating windows.
1138<p> This method is non-portable. It is available <em>only</em> in Qt/Embedded.
1139<p> <p>See also <a href="qwsdecoration.html">QWSDecoration</a>.
1140
1141<h3 class=fn>bool <a name="qwsEventFilter"></a>QApplication::qwsEventFilter ( QWSEvent * )<tt> [virtual]</tt>
1142</h3>
1143This virtual function is only implemented under Qt/Embedded.
1144<p> If you create an application that inherits QApplication and
1145reimplement this function, you get direct access to all QWS (Q
1146Window System) events that the are received from the QWS master
1147process.
1148<p> Return TRUE if you want to stop the event from being processed.
1149Return FALSE for normal event dispatching.
1150
1151<h3 class=fn>void <a name="qwsSetCustomColors"></a>QApplication::qwsSetCustomColors ( QRgb&nbsp;*&nbsp;colorTable, int&nbsp;start, int&nbsp;numColors )
1152</h3>
1153Set Qt/Embedded custom color table.
1154<p> Qt/Embedded on 8-bpp displays allocates a standard 216 color cube.
1155The remaining 40 colors may be used by setting a custom color
1156table in the QWS master process before any clients connect.
1157<p> <em>colorTable</em> is an array of up to 40 custom colors. <em>start</em> is
1158the starting index (0-39) and <em>numColors</em> is the number of colors
1159to be set (1-40).
1160<p> This method is non-portable. It is available <em>only</em> in
1161Qt/Embedded.
1162
1163<h3 class=fn>void <a name="qwsSetDecoration"></a>QApplication::qwsSetDecoration ( <a href="qwsdecoration.html">QWSDecoration</a>&nbsp;*&nbsp;d )<tt> [static]</tt>
1164</h3>
1165Set the <a href="qwsdecoration.html">QWSDecoration</a> derived class to use for decorating the
1166Qt/Embedded windows to <em>d</em>.
1167<p> This method is non-portable. It is available <em>only</em> in
1168Qt/Embedded.
1169<p> <p>See also <a href="qwsdecoration.html">QWSDecoration</a>.
1170
1171<h3 class=fn>void <a name="removeLibraryPath"></a>QApplication::removeLibraryPath ( const&nbsp;<a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;path )<tt> [static]</tt>
1172</h3>
1173Removes <em>path</em> from the library path list. If <em>path</em> is empty or not
1174in the path list, the list is not changed.
1175<p> <p>See also <a href="#addLibraryPath">addLibraryPath</a>(), <a href="#libraryPaths">libraryPaths</a>(), and <a href="#setLibraryPaths">setLibraryPaths</a>().
1176
1177<h3 class=fn>void <a name="removePostedEvents"></a>QApplication::removePostedEvents ( <a href="qobject.html">QObject</a>&nbsp;*&nbsp;receiver )<tt> [static]</tt>
1178</h3><p><b>Note:</b> This function is <a href="threads.html#threadsafe">thread-safe</a> when Qt is built withthread support.</p>
1179
1180Removes all events posted using <a href="#postEvent">postEvent</a>() for <em>receiver</em>.
1181<p> The events are <em>not</em> dispatched, instead they are removed from the
1182queue. You should never need to call this function. If you do call it,
1183be aware that killing events may cause <em>receiver</em> to break one or
1184more invariants.
1185<p>
1186
1187<h3 class=fn>void <a name="removeTranslator"></a>QApplication::removeTranslator ( <a href="qtranslator.html">QTranslator</a>&nbsp;*&nbsp;mf )
1188</h3>
1189Removes the message file <em>mf</em> from the list of message files used by
1190this application. (It does not delete the message file from the file
1191system.)
1192<p> <p>See also <a href="#installTranslator">installTranslator</a>(), <a href="#translate">translate</a>(), and <a href="qobject.html#tr">QObject::tr</a>().
1193
1194<p>Example: <a href="i18n-example.html#x1932">i18n/main.cpp</a>.
1195<h3 class=fn>void <a name="restoreOverrideCursor"></a>QApplication::restoreOverrideCursor ()<tt> [static]</tt>
1196</h3>
1197Undoes the last <a href="#setOverrideCursor">setOverrideCursor</a>().
1198<p> If setOverrideCursor() has been called twice, calling
1199<a href="#restoreOverrideCursor">restoreOverrideCursor</a>() will activate the first cursor set.
1200Calling this function a second time restores the original widgets'
1201cursors.
1202<p> <p>See also <a href="#setOverrideCursor">setOverrideCursor</a>() and <a href="#overrideCursor">overrideCursor</a>().
1203
1204<p>Examples: <a href="distributor-example.html#x2652">distributor/distributor.ui.h</a>, <a href="archivesearch-example.html#x473">network/archivesearch/archivedialog.ui.h</a>, <a href="ftpclient-example.html#x737">network/ftpclient/ftpmainwindow.ui.h</a>, and <a href="showimg-example.html#x1311">showimg/showimg.cpp</a>.
1205<h3 class=fn>bool <a name="reverseLayout"></a>QApplication::reverseLayout ()<tt> [static]</tt>
1206</h3>
1207Returns TRUE if all dialogs and widgets will be laid out in a
1208mirrored (right to left) fashion. Returns FALSE if dialogs and
1209widgets will be laid out left to right.
1210<p> <p>See also <a href="#setReverseLayout">setReverseLayout</a>().
1211
1212<h3 class=fn>void <a name="saveState"></a>QApplication::saveState ( <a href="qsessionmanager.html">QSessionManager</a>&nbsp;&amp;&nbsp;sm )<tt> [virtual]</tt>
1213</h3>
1214
1215<p> This function deals with <a href="session.html">session
1216 management</a>. It is invoked when the
1217<a href="qsessionmanager.html">session manager</a> wants the application
1218to preserve its state for a future session.
1219<p> For example, a text editor would create a temporary file that
1220includes the current contents of its edit buffers, the location of
1221the cursor and other aspects of the current editing session.
1222<p> Note that you should never exit the application within this
1223function. Instead, the session manager may or may not do this
1224afterwards, depending on the context. Futhermore, most session
1225managers will very likely request a saved state immediately after
1226the application has been started. This permits the session manager
1227to learn about the application's restart policy.
1228<p> <b>Warning:</b> Within this function, no user interaction is possible, <em>unless</em> you ask the session manager <em>sm</em> for explicit permission.
1229See <a href="qsessionmanager.html#allowsInteraction">QSessionManager::allowsInteraction</a>() and
1230<a href="qsessionmanager.html#allowsErrorInteraction">QSessionManager::allowsErrorInteraction</a>() for details.
1231<p> <p>See also <a href="#isSessionRestored">isSessionRestored</a>(), <a href="#sessionId">sessionId</a>(), <a href="#commitData">commitData</a>(), and <a href="session.html">the Session Management overview</a>.
1232
1233<h3 class=fn>bool <a name="sendEvent"></a>QApplication::sendEvent ( <a href="qobject.html">QObject</a>&nbsp;*&nbsp;receiver, <a href="qevent.html">QEvent</a>&nbsp;*&nbsp;event )<tt> [static]</tt>
1234</h3>
1235
1236<p> Sends event <em>event</em> directly to receiver <em>receiver</em>, using the
1237<a href="#notify">notify</a>() function. Returns the value that was returned from the event
1238handler.
1239<p> The event is <em>not</em> deleted when the event has been sent. The normal
1240approach is to create the event on the stack, e.g.
1241<pre>
1242 <a href="qmouseevent.html">QMouseEvent</a> me( QEvent::MouseButtonPress, pos, 0, 0 );
1243 QApplication::<a href="#sendEvent">sendEvent</a>( mainWindow, &amp;me );
1244 </pre>
1245
1246If you create the event on the heap you must delete it.
1247<p> <p>See also <a href="#postEvent">postEvent</a>() and <a href="#notify">notify</a>().
1248
1249<p>Example: <a href="popup-example.html#x1602">popup/popup.cpp</a>.
1250<h3 class=fn>void <a name="sendPostedEvents"></a>QApplication::sendPostedEvents ( <a href="qobject.html">QObject</a>&nbsp;*&nbsp;receiver, int&nbsp;event_type )<tt> [static]</tt>
1251</h3>
1252Immediately dispatches all events which have been previously queued
1253with <a href="#postEvent">QApplication::postEvent</a>() and which are for the object <em>receiver</em>
1254and have the event type <em>event_type</em>.
1255<p> Note that events from the window system are <em>not</em> dispatched by this
1256function, but by <a href="#processEvents">processEvents</a>().
1257<p> If <em>receiver</em> is null, the events of <em>event_type</em> are sent for all
1258objects. If <em>event_type</em> is 0, all the events are sent for <em>receiver</em>.
1259
1260<h3 class=fn>void <a name="sendPostedEvents-2"></a>QApplication::sendPostedEvents ()<tt> [static]</tt>
1261</h3> This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
1262<p> Dispatches all posted events, i.e. empties the event queue.
1263
1264<h3 class=fn><a href="qstring.html">QString</a> <a name="sessionId"></a>QApplication::sessionId () const
1265</h3>
1266
1267<p> Returns the current <a href="session.html">session's</a> identifier.
1268<p> If the application has been restored from an earlier session, this
1269identifier is the same as it was in that previous session.
1270<p> The session identifier is guaranteed to be unique both for different
1271applications and for different instances of the same application.
1272<p> <p>See also <a href="#isSessionRestored">isSessionRestored</a>(), <a href="#sessionKey">sessionKey</a>(), <a href="#commitData">commitData</a>(), and <a href="#saveState">saveState</a>().
1273
1274<h3 class=fn><a href="qstring.html">QString</a> <a name="sessionKey"></a>QApplication::sessionKey () const
1275</h3>
1276
1277<p> Returns the session key in the current <a href="session.html">session</a>.
1278<p> If the application has been restored from an earlier session, this
1279key is the same as it was when the previous session ended.
1280<p> The session key changes with every call of <a href="#commitData">commitData</a>() or
1281<a href="#saveState">saveState</a>().
1282<p> <p>See also <a href="#isSessionRestored">isSessionRestored</a>(), <a href="#sessionId">sessionId</a>(), <a href="#commitData">commitData</a>(), and <a href="#saveState">saveState</a>().
1283
1284<h3 class=fn>void <a name="setColorSpec"></a>QApplication::setColorSpec ( int&nbsp;spec )<tt> [static]</tt>
1285</h3>
1286Sets the color specification for the application to <em>spec</em>.
1287<p> The color specification controls how the application allocates colors
1288when run on a display with a limited amount of colors, e.g. 8 bit / 256
1289color displays.
1290<p> The color specification must be set before you create the QApplication
1291object.
1292<p> The options are:
1293<ul>
1294<li> QApplication::NormalColor.
1295This is the default color allocation strategy. Use this option if
1296your application uses buttons, menus, texts and pixmaps with few
1297colors. With this option, the application uses system global
1298colors. This works fine for most applications under X11, but on
1299Windows machines it may cause dithering of non-standard colors.
1300<li> QApplication::CustomColor.
1301Use this option if your application needs a small number of custom
1302colors. On X11, this option is the same as NormalColor. On Windows, Qt
1303creates a Windows palette, and allocates colors to it on demand.
1304<li> QApplication::ManyColor.
1305Use this option if your application is very color hungry
1306(e.g. it requires thousands of colors).
1307Under X11 the effect is:
1308<ul>
1309<li> For 256-color displays which have at best a 256 color true color
1310visual, the default visual is used, and colors are allocated
1311from a color cube. The color cube is the 6x6x6 (216 color) "Web
1312palette"<sup>*</sup>, but the number of colors can be changed
1313by the <em>-ncols</em> option. The user can force the application to
1314use the true color visual with the <a href="#QApplication">-visual</a> option.
1315<li> For 256-color displays which have a true color visual with more
1316than 256 colors, use that visual. Silicon Graphics X servers
1317have this feature, for example. They provide an 8 bit visual
1318by default but can deliver true color when asked.
1319</ul>
1320On Windows, Qt creates a Windows palette, and fills it with a color cube.
1321</ul>
1322<p> Be aware that the CustomColor and ManyColor choices may lead to colormap
1323flashing: The foreground application gets (most) of the available
1324colors, while the background windows will look less attractive.
1325<p> Example:
1326<pre>
1327 int main( int argc, char **argv )
1328 {
1329 QApplication::<a href="#setColorSpec">setColorSpec</a>( QApplication::<a href="#ColorSpec-enum">ManyColor</a> );
1330 QApplication a( argc, argv );
1331 ...
1332 }
1333 </pre>
1334
1335<p> <a href="qcolor.html">QColor</a> provides more functionality for controlling color allocation and
1336freeing up certain colors. See <a href="qcolor.html#enterAllocContext">QColor::enterAllocContext</a>() for more
1337information.
1338<p> To check what mode you end up with, call <a href="qcolor.html#numBitPlanes">QColor::numBitPlanes</a>() once
1339the QApplication object exists. A value greater than 8 (typically
134016, 24 or 32) means true color.
1341<p> <sup>*</sup> The color cube used by Qt has 216 colors whose red,
1342green, and blue components always have one of the following values:
13430x00, 0x33, 0x66, 0x99, 0xCC, or 0xFF.
1344<p> <p>See also <a href="#colorSpec">colorSpec</a>(), <a href="qcolor.html#numBitPlanes">QColor::numBitPlanes</a>(), and <a href="qcolor.html#enterAllocContext">QColor::enterAllocContext</a>().
1345
1346<p>Examples: <a href="helpviewer-example.html#x1041">helpviewer/main.cpp</a>, <a href="qaxserver-example-opengl.html#x2732">opengl/main.cpp</a>, <a href="showimg-example.html#x1361">showimg/main.cpp</a>, <a href="tutorial1-09.html#x2347">t9/main.cpp</a>, <a href="qaxserver-example-tetrax.html#x2716">tetrax/tetrax.cpp</a>, <a href="tetrix-example.html#x354">tetrix/tetrix.cpp</a>, and <a href="themes-example.html#x348">themes/main.cpp</a>.
1347<h3 class=fn>void <a name="setCursorFlashTime"></a>QApplication::setCursorFlashTime ( int&nbsp;msecs )<tt> [static]</tt>
1348</h3>
1349Sets the text cursor's flash (blink) time to <em>msecs</em>
1350milliseconds. The flash time is the time required to display,
1351invert and restore the caret display. Usually the text cursor is
1352displayed for <em>msecs/2</em> milliseconds, then hidden for <em>msecs/2</em>
1353milliseconds, but this may vary.
1354<p> Note that on Microsoft Windows, calling this function sets the
1355cursor flash time for all windows.
1356<p> <p>See also <a href="#cursorFlashTime">cursorFlashTime</a>().
1357
1358<h3 class=fn>void <a name="setDefaultCodec"></a>QApplication::setDefaultCodec ( <a href="qtextcodec.html">QTextCodec</a>&nbsp;*&nbsp;codec )
1359</h3> <b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
1360<p> This is the same as <a href="qtextcodec.html#setCodecForTr">QTextCodec::setCodecForTr</a>().
1361
1362<h3 class=fn>void <a name="setDesktopSettingsAware"></a>QApplication::setDesktopSettingsAware ( bool&nbsp;on )<tt> [static]</tt>
1363</h3>
1364By default, Qt will try to use the current standard colors, fonts
1365etc., from the underlying window system's desktop settings,
1366and use them for all relevant widgets. This behavior can be switched off
1367by calling this function with <em>on</em> set to FALSE.
1368<p> This static function must be called before creating the QApplication
1369object, like this:
1370<p> <pre>
1371 int main( int argc, char** argv ) {
1372 QApplication::<a href="#setDesktopSettingsAware">setDesktopSettingsAware</a>( FALSE ); // I know better than the user
1373 QApplication myApp( argc, argv ); // Use default fonts &amp; colors
1374 ...
1375 }
1376 </pre>
1377
1378<p> <p>See also <a href="#desktopSettingsAware">desktopSettingsAware</a>().
1379
1380<h3 class=fn>void <a name="setDoubleClickInterval"></a>QApplication::setDoubleClickInterval ( int&nbsp;ms )<tt> [static]</tt>
1381</h3>
1382Sets the time limit that distinguishes a double click from two
1383consecutive mouse clicks to <em>ms</em> milliseconds.
1384<p> Note that on Microsoft Windows, calling this function sets the
1385double click interval for all windows.
1386<p> <p>See also <a href="#doubleClickInterval">doubleClickInterval</a>().
1387
1388<h3 class=fn>void <a name="setEffectEnabled"></a>QApplication::setEffectEnabled ( <a href="qt.html#UIEffect-enum">Qt::UIEffect</a>&nbsp;effect, bool&nbsp;enable = TRUE )<tt> [static]</tt>
1389</h3>
1390Enables the UI effect <em>effect</em> if <em>enable</em> is TRUE, otherwise
1391the effect will not be used.
1392<p> Note: All effects are disabled on screens running at less than
139316-bit color depth.
1394<p> <p>See also <a href="#isEffectEnabled">isEffectEnabled</a>(), <a href="qt.html#UIEffect-enum">Qt::UIEffect</a>, and <a href="#setDesktopSettingsAware">setDesktopSettingsAware</a>().
1395
1396<h3 class=fn>void <a name="setFont"></a>QApplication::setFont ( const&nbsp;<a href="qfont.html">QFont</a>&nbsp;&amp;&nbsp;font, bool&nbsp;informWidgets = FALSE, const&nbsp;char&nbsp;*&nbsp;className = 0 )<tt> [static]</tt>
1397</h3> Changes the default application font to <em>font</em>. If <em>informWidgets</em> is TRUE, then existing widgets are informed about the
1398change and may adjust themselves to the new application
1399setting. If <em>informWidgets</em> is FALSE, the change only affects newly
1400created widgets. If <em>className</em> is passed, the change applies only
1401to classes that inherit <em>className</em> (as reported by
1402<a href="qobject.html#inherits">QObject::inherits</a>()).
1403<p> On application start-up, the default font depends on the window
1404system. It can vary depending on both the window system version and
1405the locale. This function lets you override the default font; but
1406overriding may be a bad idea because, for example, some locales need
1407extra-large fonts to support their special characters.
1408<p> <p>See also <a href="#font">font</a>(), <a href="#fontMetrics">fontMetrics</a>(), and <a href="qwidget.html#font-prop">QWidget::font</a>.
1409
1410<p>Examples: <a href="desktop-example.html#x1724">desktop/desktop.cpp</a>, <a href="themes-example.html#x266">themes/metal.cpp</a>, and <a href="themes-example.html#x323">themes/themes.cpp</a>.
1411<h3 class=fn>void <a name="setGlobalMouseTracking"></a>QApplication::setGlobalMouseTracking ( bool&nbsp;enable )<tt> [static]</tt>
1412</h3>
1413Enables global mouse tracking if <em>enable</em> is TRUE, or disables it
1414if <em>enable</em> is FALSE.
1415<p> Enabling global mouse tracking makes it possible for widget event
1416filters or application event filters to get all mouse move events,
1417even when no button is depressed. This is useful for special GUI
1418elements, e.g. tooltips.
1419<p> Global mouse tracking does not affect widgets and their
1420mouseMoveEvent(). For a widget to get mouse move events when no
1421button is depressed, it must do <a href="qwidget.html#setMouseTracking">QWidget::setMouseTracking</a>(TRUE).
1422<p> This function uses an internal counter. Each
1423<a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>(TRUE) must have a corresponding
1424setGlobalMouseTracking(FALSE):
1425<pre>
1426 // at this point global mouse tracking is off
1427 QApplication::<a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>( TRUE );
1428 QApplication::<a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>( TRUE );
1429 QApplication::<a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>( FALSE );
1430 // at this point it's still on
1431 QApplication::<a href="#setGlobalMouseTracking">setGlobalMouseTracking</a>( FALSE );
1432 // but now it's off
1433 </pre>
1434
1435<p> <p>See also <a href="#hasGlobalMouseTracking">hasGlobalMouseTracking</a>() and <a href="qwidget.html#mouseTracking-prop">QWidget::mouseTracking</a>.
1436
1437<h3 class=fn>void <a name="setGlobalStrut"></a>QApplication::setGlobalStrut ( const&nbsp;<a href="qsize.html">QSize</a>&nbsp;&amp;&nbsp;strut )<tt> [static]</tt>
1438</h3>
1439Sets the application's global strut to <em>strut</em>.
1440<p> The strut is a size object whose dimensions are the minimum that any
1441GUI element that the user can interact with should have. For example
1442no button should be resized to be smaller than the global strut size.
1443<p> The strut size should be considered when reimplementing GUI controls
1444that may be used on touch-screens or similar IO-devices.
1445<p> Example:
1446<pre>
1447 QSize&amp; WidgetClass::sizeHint() const
1448 {
1449 return QSize( 80, 25 ).expandedTo( QApplication::<a href="#globalStrut">globalStrut</a>() );
1450 }
1451 </pre>
1452
1453<p> <p>See also <a href="#globalStrut">globalStrut</a>().
1454
1455<h3 class=fn>void <a name="setLibraryPaths"></a>QApplication::setLibraryPaths ( const&nbsp;<a href="qstringlist.html">QStringList</a>&nbsp;&amp;&nbsp;paths )<tt> [static]</tt>
1456</h3>
1457Sets the list of directories to search when loading libraries to <em>paths</em>.
1458All existing paths will be deleted and the path list will consist of the
1459paths given in <em>paths</em>.
1460<p> <p>See also <a href="#libraryPaths">libraryPaths</a>(), <a href="#addLibraryPath">addLibraryPath</a>(), <a href="#removeLibraryPath">removeLibraryPath</a>(), and <a href="qlibrary.html">QLibrary</a>.
1461
1462<h3 class=fn>void <a name="setMainWidget"></a>QApplication::setMainWidget ( <a href="qwidget.html">QWidget</a>&nbsp;*&nbsp;mainWidget )<tt> [virtual]</tt>
1463</h3>
1464Sets the application's main widget to <em>mainWidget</em>.
1465<p> In most respects the main widget is like any other widget, except
1466that if it is closed, the application exits. Note that
1467QApplication does <em>not</em> take ownership of the <em>mainWidget</em>, so
1468if you create your main widget on the heap you must delete it
1469yourself.
1470<p> You need not have a main widget; connecting <a href="#lastWindowClosed">lastWindowClosed</a>() to
1471<a href="#quit">quit</a>() is an alternative.
1472<p> For X11, this function also resizes and moves the main widget
1473according to the <em>-geometry</em> command-line option, so you should
1474set the default geometry (using <a href="qwidget.html#setGeometry">QWidget::setGeometry</a>()) before
1475calling <a href="#setMainWidget">setMainWidget</a>().
1476<p> <p>See also <a href="#mainWidget">mainWidget</a>(), <a href="#exec">exec</a>(), and <a href="#quit">quit</a>().
1477
1478<p>Examples: <a href="tutorial2-04.html#x2560">chart/main.cpp</a>, <a href="helpsystem-example.html#x2701">helpsystem/main.cpp</a>, <a href="qdialog.html#x2133">life/main.cpp</a>, <a href="ftpclient-example.html#x779">network/ftpclient/main.cpp</a>, <a href="qaxserver-example-opengl.html#x2733">opengl/main.cpp</a>, <a href="tutorial1-01.html#x2284">t1/main.cpp</a>, and <a href="tutorial1-04.html#x2305">t4/main.cpp</a>.
1479<h3 class=fn>void <a name="setOverrideCursor"></a>QApplication::setOverrideCursor ( const&nbsp;<a href="qcursor.html">QCursor</a>&nbsp;&amp;&nbsp;cursor, bool&nbsp;replace = FALSE )<tt> [static]</tt>
1480</h3>
1481Sets the application override cursor to <em>cursor</em>.
1482<p> Application override cursors are intended for showing the user
1483that the application is in a special state, for example during an
1484operation that might take some time.
1485<p> This cursor will be displayed in all the application's widgets
1486until <a href="#restoreOverrideCursor">restoreOverrideCursor</a>() or another <a href="#setOverrideCursor">setOverrideCursor</a>() is
1487called.
1488<p> Application cursors are stored on an internal stack.
1489setOverrideCursor() pushes the cursor onto the stack, and
1490restoreOverrideCursor() pops the active cursor off the stack.
1491Every setOverrideCursor() must eventually be followed by a
1492corresponding restoreOverrideCursor(), otherwise the stack will
1493never be emptied.
1494<p> If <em>replace</em> is TRUE, the new cursor will replace the last
1495override cursor (the stack keeps its depth). If <em>replace</em> is
1496FALSE, the new stack is pushed onto the top of the stack.
1497<p> Example:
1498<pre>
1499 QApplication::<a href="#setOverrideCursor">setOverrideCursor</a>( QCursor(Qt::<a href="qt.html#CursorShape-enum">WaitCursor</a>) );
1500 calculateHugeMandelbrot(); // lunch time...
1501 QApplication::<a href="#restoreOverrideCursor">restoreOverrideCursor</a>();
1502 </pre>
1503
1504<p> <p>See also <a href="#overrideCursor">overrideCursor</a>(), <a href="#restoreOverrideCursor">restoreOverrideCursor</a>(), and <a href="qwidget.html#cursor-prop">QWidget::cursor</a>.
1505
1506<p>Examples: <a href="distributor-example.html#x2653">distributor/distributor.ui.h</a>, <a href="archivesearch-example.html#x474">network/archivesearch/archivedialog.ui.h</a>, <a href="ftpclient-example.html#x738">network/ftpclient/ftpmainwindow.ui.h</a>, and <a href="showimg-example.html#x1312">showimg/showimg.cpp</a>.
1507<h3 class=fn>void <a name="setPalette"></a>QApplication::setPalette ( const&nbsp;<a href="qpalette.html">QPalette</a>&nbsp;&amp;&nbsp;palette, bool&nbsp;informWidgets = FALSE, const&nbsp;char&nbsp;*&nbsp;className = 0 )<tt> [static]</tt>
1508</h3>
1509Changes the default application palette to <em>palette</em>. If <em>informWidgets</em> is TRUE, then existing widgets are informed about the
1510change and may adjust themselves to the new application
1511setting. If <em>informWidgets</em> is FALSE, the change only affects newly
1512created widgets.
1513<p> If <em>className</em> is passed, the change applies only to widgets that
1514inherit <em>className</em> (as reported by <a href="qobject.html#inherits">QObject::inherits</a>()). If
1515<em>className</em> is left 0, the change affects all widgets, thus overriding
1516any previously set class specific palettes.
1517<p> The palette may be changed according to the current GUI style in
1518<a href="qstyle.html#polish">QStyle::polish</a>().
1519<p> <p>See also <a href="qwidget.html#palette-prop">QWidget::palette</a>, <a href="#palette">palette</a>(), and <a href="qstyle.html#polish">QStyle::polish</a>().
1520
1521<p>Examples: <a href="i18n-example.html#x1934">i18n/main.cpp</a>, <a href="themes-example.html#x267">themes/metal.cpp</a>, <a href="themes-example.html#x324">themes/themes.cpp</a>, and <a href="themes-example.html#x187">themes/wood.cpp</a>.
1522<h3 class=fn>void <a name="setReverseLayout"></a>QApplication::setReverseLayout ( bool&nbsp;b )<tt> [static]</tt>
1523</h3>
1524If <em>b</em> is TRUE, all dialogs and widgets will be laid out in a
1525mirrored fashion, as required by right to left languages such as
1526Arabic and Hebrew. If <em>b</em> is FALSE, dialogs and widgets are laid
1527out left to right.
1528<p> Changing this flag in runtime does not cause a relayout of already
1529instantiated widgets.
1530<p> <p>See also <a href="#reverseLayout">reverseLayout</a>().
1531
1532<h3 class=fn>void <a name="setStartDragDistance"></a>QApplication::setStartDragDistance ( int&nbsp;l )<tt> [static]</tt>
1533</h3>
1534Sets the distance after which a drag should start to <em>l</em> pixels.
1535<p> <p>See also <a href="#startDragDistance">startDragDistance</a>().
1536
1537<h3 class=fn>void <a name="setStartDragTime"></a>QApplication::setStartDragTime ( int&nbsp;ms )<tt> [static]</tt>
1538</h3>
1539Sets the time after which a drag should start to <em>ms</em> ms.
1540<p> <p>See also <a href="#startDragTime">startDragTime</a>().
1541
1542<h3 class=fn>void <a name="setStyle"></a>QApplication::setStyle ( <a href="qstyle.html">QStyle</a>&nbsp;*&nbsp;style )<tt> [static]</tt>
1543</h3>
1544Sets the application's GUI style to <em>style</em>. Ownership of the style
1545object is transferred to QApplication, so QApplication will delete
1546the style object on application exit or when a new style is set.
1547<p> Example usage:
1548<pre>
1549 QApplication::<a href="#setStyle">setStyle</a>( new <a href="qwindowsstyle.html">QWindowsStyle</a> );
1550 </pre>
1551
1552<p> When switching application styles, the color palette is set back to
1553the initial colors or the system defaults. This is necessary since
1554certain styles have to adapt the color palette to be fully
1555style-guide compliant.
1556<p> <p>See also <a href="#style">style</a>(), <a href="qstyle.html">QStyle</a>, <a href="#setPalette">setPalette</a>(), and <a href="#desktopSettingsAware">desktopSettingsAware</a>().
1557
1558<p>Example: <a href="themes-example.html#x325">themes/themes.cpp</a>.
1559<h3 class=fn><a href="qstyle.html">QStyle</a>&nbsp;* <a name="setStyle-2"></a>QApplication::setStyle ( const&nbsp;<a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;style )<tt> [static]</tt>
1560</h3>
1561This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
1562<p> Requests a <a href="qstyle.html">QStyle</a> object for <em>style</em> from the <a href="qstylefactory.html">QStyleFactory</a>.
1563<p> The string must be one of the <a href="qstylefactory.html#keys">QStyleFactory::keys</a>(), typically one
1564of "windows", "motif", "cde", "motifplus", "platinum", "sgi" and
1565"compact". Depending on the platform, "windowsxp", "aqua" or
1566"macintosh" may be available.
1567<p> A later call to the QApplication constructor will override the
1568requested style when a "-style" option is passed in as a commandline
1569parameter.
1570<p> Returns 0 if an unknown <em>style</em> is passed, otherwise the QStyle object
1571returned is set as the application's GUI style.
1572
1573<h3 class=fn>void <a name="setWheelScrollLines"></a>QApplication::setWheelScrollLines ( int&nbsp;n )<tt> [static]</tt>
1574</h3>
1575Sets the number of lines to scroll when the mouse wheel is rotated
1576to <em>n</em>.
1577<p> If this number exceeds the number of visible lines in a certain
1578widget, the widget should interpret the scroll operation as a
1579single page up / page down operation instead.
1580<p> <p>See also <a href="#wheelScrollLines">wheelScrollLines</a>().
1581
1582<h3 class=fn>void <a name="setWinStyleHighlightColor"></a>QApplication::setWinStyleHighlightColor ( const&nbsp;<a href="qcolor.html">QColor</a>&nbsp;&amp;&nbsp;c )<tt> [static]</tt>
1583</h3>
1584
1585<b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
1586<p> Sets the color used to mark selections in windows style for all widgets
1587in the application. Will repaint all widgets if the color is changed.
1588<p> The default color is <tt>darkBlue</tt>.
1589<p>See also <a href="#winStyleHighlightColor">winStyleHighlightColor</a>().
1590
1591<h3 class=fn>int <a name="startDragDistance"></a>QApplication::startDragDistance ()<tt> [static]</tt>
1592</h3>
1593If you support drag and drop in you application and a drag should
1594start after a mouse click and after moving the mouse a certain
1595distance, you should use the value which this method returns as the
1596distance.
1597<p> For example, if the mouse position of the click is stored in <tt>startPos</tt> and the current position (e.g. in the mouse move event) is
1598<tt>currPos</tt>, you can find out if a drag should be started with code
1599like this:
1600<pre>
1601 if ( ( startPos - currPos ).manhattanLength() &gt;
1602 QApplication::<a href="#startDragDistance">startDragDistance</a>() )
1603 startTheDrag();
1604 </pre>
1605
1606<p> Qt uses this value internally, e.g. in <a href="qfiledialog.html">QFileDialog</a>.
1607<p> The default value is 4 pixels.
1608<p> <p>See also <a href="#setStartDragDistance">setStartDragDistance</a>(), <a href="#startDragTime">startDragTime</a>(), and <a href="qpoint.html#manhattanLength">QPoint::manhattanLength</a>().
1609
1610<h3 class=fn>int <a name="startDragTime"></a>QApplication::startDragTime ()<tt> [static]</tt>
1611</h3>
1612If you support drag and drop in you application and a drag should
1613start after a mouse click and after a certain time elapsed, you
1614should use the value which this method returns as the delay (in ms).
1615<p> Qt also uses this delay internally, e.g. in <a href="qtextedit.html">QTextEdit</a> and <a href="qlineedit.html">QLineEdit</a>,
1616for starting a drag.
1617<p> The default value is 500 ms.
1618<p> <p>See also <a href="#setStartDragTime">setStartDragTime</a>() and <a href="#startDragDistance">startDragDistance</a>().
1619
1620<h3 class=fn>bool <a name="startingUp"></a>QApplication::startingUp ()<tt> [static]</tt>
1621</h3>
1622Returns TRUE if an application object has not been created yet;
1623otherwise returns FALSE.
1624<p> <p>See also <a href="#closingDown">closingDown</a>().
1625
1626<h3 class=fn><a href="qstyle.html">QStyle</a>&nbsp;&amp; <a name="style"></a>QApplication::style ()<tt> [static]</tt>
1627</h3>
1628Returns the application's style object.
1629<p> <p>See also <a href="#setStyle">setStyle</a>() and <a href="qstyle.html">QStyle</a>.
1630
1631<h3 class=fn>void <a name="syncX"></a>QApplication::syncX ()<tt> [static]</tt>
1632</h3>
1633Synchronizes with the X server in the X11 implementation. This
1634normally takes some time. Does nothing on other platforms.
1635<p> <p>See also <a href="#flushX">flushX</a>().
1636
1637<h3 class=fn>QWidgetList * <a name="topLevelWidgets"></a>QApplication::topLevelWidgets ()<tt> [static]</tt>
1638</h3>
1639Returns a list of the top level widgets in the application.
1640<p> The list is created using <tt>new</tt> and must be deleted by the caller.
1641<p> The list is empty (<a href="qptrlist.html#isEmpty">QPtrList::isEmpty</a>()) if there are no top level
1642widgets.
1643<p> Note that some of the top level widgets may be hidden, for example
1644the tooltip if no tooltip is currently shown.
1645<p> Example:
1646<pre>
1647 // Show all hidden top level widgets.
1648 QWidgetList *list = QApplication::<a href="#topLevelWidgets">topLevelWidgets</a>();
1649 QWidgetListIt it( *list ); // iterate over the widgets
1650 <a href="qwidget.html">QWidget</a> * w;
1651 while ( (w=it.current()) != 0 ) { // for each top level widget...
1652 ++it;
1653 if ( !w-&gt;<a href="qwidget.html#isVisible">isVisible</a>() )
1654 w-&gt;<a href="qwidget.html#show">show</a>();
1655 }
1656 delete list; // delete the list, not the widgets
1657 </pre>
1658
1659<p> <b>Warning:</b> Delete the list as soon you have finished using it.
1660The widgets in the list may be deleted by someone else at any time.
1661<p> <p>See also <a href="#allWidgets">allWidgets</a>(), <a href="qwidget.html#isTopLevel-prop">QWidget::isTopLevel</a>, <a href="qwidget.html#visible-prop">QWidget::visible</a>, and <a href="qptrlist.html#isEmpty">QPtrList::isEmpty</a>().
1662
1663<h3 class=fn><a href="qstring.html">QString</a> <a name="translate"></a>QApplication::translate ( const&nbsp;char&nbsp;*&nbsp;context, const&nbsp;char&nbsp;*&nbsp;sourceText, const&nbsp;char&nbsp;*&nbsp;comment = 0, <a href="qapplication.html#Encoding-enum">Encoding</a>&nbsp;encoding = DefaultCodec ) const
1664</h3><p><b>Note:</b> This function is <a href="threads.html#reentrant">reentrant</a> when Qt is built with thread support.</p>
1665
1666Returns the translation text for <em>sourceText</em>, by querying the
1667installed messages files. The message files are searched from the most
1668recently installed message file back to the first installed message
1669file.
1670<p> <a href="qobject.html#tr">QObject::tr</a>() and <a href="qobject.html#trUtf8">QObject::trUtf8</a>() provide this functionality more
1671conveniently.
1672<p> <em>context</em> is typically a class name (e.g., "MyDialog") and
1673<em>sourceText</em> is either English text or a short identifying text, if
1674the output text will be very long (as for help texts).
1675<p> <em>comment</em> is a disambiguating comment, for when the same <em>sourceText</em> is used in different roles within the same context. By
1676default, it is null. <em>encoding</em> indicates the 8-bit encoding of
1677character stings
1678<p> See the <a href="qtranslator.html">QTranslator</a> documentation for more information about
1679contexts and comments.
1680<p> If none of the message files contain a translation for <em>sourceText</em> in <em>context</em>, this function returns a <a href="qstring.html">QString</a>
1681equivalent of <em>sourceText</em>. The encoding of <em>sourceText</em> is
1682specified by <em>encoding</em>; it defaults to <a href="#Encoding-enum">DefaultCodec</a>.
1683<p> This function is not virtual. You can use alternative translation
1684techniques by subclassing <a href="qtranslator.html">QTranslator</a>.
1685<p> <b>Warning:</b> This method is reentrant only if all translators are
1686installed <em>before</em> calling this method. Installing or removing
1687translators while performing translations is not supported. Doing
1688so will most likely result in crashes or other undesirable behavior.
1689<p> <p>See also <a href="qobject.html#tr">QObject::tr</a>(), <a href="#installTranslator">installTranslator</a>(), and <a href="#defaultCodec">defaultCodec</a>().
1690
1691<h3 class=fn>bool <a name="tryLock"></a>QApplication::tryLock ()
1692</h3>
1693<p> Attempts to lock the Qt Library Mutex, and returns immediately. If
1694the lock was obtained, this function returns TRUE. If another thread
1695has locked the mutex, this function returns FALSE, instead of
1696waiting for the lock to become available.
1697<p> The mutex must be unlocked with <a href="#unlock">unlock</a>() before another thread can
1698successfully lock it.
1699<p> <p>See also <a href="#lock">lock</a>(), <a href="#unlock">unlock</a>(), and <a href="threads.html">Thread Support in Qt</a>.
1700
1701<h3 class=fn><a href="qapplication.html#Type-enum">Type</a> <a name="type"></a>QApplication::type () const
1702</h3>
1703Returns the type of application, Tty, GuiClient or GuiServer.
1704
1705<h3 class=fn>void <a name="unlock"></a>QApplication::unlock ( bool&nbsp;wakeUpGui = TRUE )
1706</h3>
1707<p> Unlock the Qt Library Mutex. If <em>wakeUpGui</em> is TRUE (the default),
1708then the GUI thread will be woken with <a href="#wakeUpGuiThread">QApplication::wakeUpGuiThread</a>().
1709<p> <p>See also <a href="#lock">lock</a>(), <a href="#locked">locked</a>(), and <a href="threads.html">Thread Support in Qt</a>.
1710
1711<h3 class=fn>void <a name="wakeUpGuiThread"></a>QApplication::wakeUpGuiThread ()
1712</h3>
1713<p> Wakes up the GUI thread.
1714<p> <p>See also <a href="#guiThreadAwake">guiThreadAwake</a>() and <a href="threads.html">Thread Support in Qt</a>.
1715
1716<h3 class=fn>int <a name="wheelScrollLines"></a>QApplication::wheelScrollLines ()<tt> [static]</tt>
1717</h3>
1718Returns the number of lines to scroll when the mouse wheel is
1719rotated.
1720<p> <p>See also <a href="#setWheelScrollLines">setWheelScrollLines</a>().
1721
1722<h3 class=fn><a href="qwidget.html">QWidget</a>&nbsp;* <a name="widgetAt"></a>QApplication::widgetAt ( int&nbsp;x, int&nbsp;y, bool&nbsp;child = FALSE )<tt> [static]</tt>
1723</h3>
1724Returns a pointer to the widget at global screen position <em>(x, y)</em>, or 0 if there is no Qt widget there.
1725<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>
1726is TRUE the child widget at position <em>(x, y)</em> is returned.
1727<p> This function is normally rather slow.
1728<p> <p>See also <a href="qcursor.html#pos">QCursor::pos</a>(), <a href="qwidget.html#grabMouse">QWidget::grabMouse</a>(), and <a href="qwidget.html#grabKeyboard">QWidget::grabKeyboard</a>().
1729
1730<h3 class=fn><a href="qwidget.html">QWidget</a>&nbsp;* <a name="widgetAt-2"></a>QApplication::widgetAt ( const&nbsp;<a href="qpoint.html">QPoint</a>&nbsp;&amp;&nbsp;pos, bool&nbsp;child = FALSE )<tt> [static]</tt>
1731</h3>
1732This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
1733<p> Returns a pointer to the widget at global screen position <em>pos</em>,
1734or 0 if there is no Qt widget there.
1735<p> If <em>child</em> is FALSE and there is a child widget at position <em>pos</em>, the top-level widget containing it is returned. If <em>child</em>
1736is TRUE the child widget at position <em>pos</em> is returned.
1737
1738<h3 class=fn>bool <a name="winEventFilter"></a>QApplication::winEventFilter ( MSG * )<tt> [virtual]</tt>
1739</h3>
1740This virtual function is only implemented under Windows.
1741<p> The message procedure calls this function for every message
1742received. Reimplement this function if you want to process window
1743messages that are not processed by Qt. If you don't want
1744the event to be processed by Qt, then return TRUE; otherwise
1745return FALSE.
1746
1747<h3 class=fn>void <a name="winFocus"></a>QApplication::winFocus ( <a href="qwidget.html">QWidget</a>&nbsp;*&nbsp;widget, bool&nbsp;gotFocus )
1748</h3>
1749This function is available only on Windows.
1750<p> If <em>gotFocus</em> is TRUE, <em>widget</em> will become the active window.
1751Otherwise the active window is reset to NULL.
1752
1753<h3 class=fn>const&nbsp;<a href="qcolor.html">QColor</a>&nbsp;&amp; <a name="winStyleHighlightColor"></a>QApplication::winStyleHighlightColor ()<tt> [static]</tt>
1754</h3>
1755
1756<b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
1757<p> Returns the color used to mark selections in windows style.
1758<p> <p>See also <a href="#setWinStyleHighlightColor">setWinStyleHighlightColor</a>().
1759
1760<h3 class=fn>bool <a name="x11EventFilter"></a>QApplication::x11EventFilter ( XEvent * )<tt> [virtual]</tt>
1761</h3>
1762This virtual function is only implemented under X11.
1763<p> If you create an application that inherits QApplication and
1764reimplement this function, you get direct access to all X events
1765that the are received from the X server.
1766<p> Return TRUE if you want to stop the event from being processed.
1767Return FALSE for normal event dispatching.
1768<p> <p>See also <a href="#x11ProcessEvent">x11ProcessEvent</a>().
1769
1770<h3 class=fn>int <a name="x11ProcessEvent"></a>QApplication::x11ProcessEvent ( XEvent&nbsp;*&nbsp;event )
1771</h3>
1772This function does the core processing of individual X
1773<em>event</em>s, normally by dispatching Qt events to the right
1774destination.
1775<p> It returns 1 if the event was consumed by special handling, 0 if
1776the <em>event</em> was consumed by normal handling, and -1 if the <em>event</em> was for an unrecognized widget.
1777<p> <p>See also <a href="#x11EventFilter">x11EventFilter</a>().
1778
1779<hr><h2>Related Functions</h2>
1780<h3 class=fn>void <a name="Q_ASSERT"></a>Q_ASSERT ( bool&nbsp;test )
1781</h3>
1782
1783<p>
1784<p> Prints a warning message containing the source code file name and
1785line number if <em>test</em> is FALSE.
1786<p> This is really a macro defined in <a href="qglobal-h.html">qglobal.h</a>.
1787<p> Q_ASSERT is useful for testing pre- and post-conditions.
1788<p> Example:
1789<pre>
1790 //
1791 // File: div.cpp
1792 //
1793
1794 #include &lt;<a href="qglobal-h.html">qglobal.h</a>&gt;
1795
1796 int divide( int a, int b )
1797 {
1798 <a href="#Q_ASSERT">Q_ASSERT</a>( b != 0 ); // this is line 9
1799 return a/b;
1800 }
1801 </pre>
1802
1803<p> If <tt>b</tt> is zero, the Q_ASSERT statement will output the following
1804message using the <a href="#qWarning">qWarning</a>() function:
1805<pre>
1806 ASSERT: "b != 0" in div.cpp (9)
1807 </pre>
1808
1809<p> <p>See also <a href="#qWarning">qWarning</a>() and <a href="debug.html">Debugging</a>.
1810
1811<h3 class=fn>void <a name="Q_CHECK_PTR"></a>Q_CHECK_PTR ( void&nbsp;*&nbsp;p )
1812</h3>
1813
1814<p>
1815<p> If <em>p</em> is 0, prints a warning message containing the source code file
1816name and line number, saying that the program ran out of memory.
1817<p> This is really a macro defined in <a href="qglobal-h.html">qglobal.h</a>.
1818<p> Example:
1819<pre>
1820 int *a;
1821
1822 <a href="#Q_CHECK_PTR">Q_CHECK_PTR</a>( a = new int[80] ); // WRONG!
1823
1824 a = new (nothrow) int[80]; // Right
1825 <a href="#Q_CHECK_PTR">Q_CHECK_PTR</a>( a );
1826 </pre>
1827
1828<p> <p>See also <a href="#qWarning">qWarning</a>() and <a href="debug.html">Debugging</a>.
1829
1830<h3 class=fn>void <a name="qAddPostRoutine"></a>qAddPostRoutine ( QtCleanUpFunction&nbsp;p )
1831</h3>
1832
1833<p> Adds a global routine that will be called from the QApplication
1834destructor. This function is normally used to add cleanup routines
1835for program-wide functionality.
1836<p> The function given by <em>p</em> should take no arguments and return
1837nothing, like this:
1838<pre>
1839 static int *global_ptr = 0;
1840
1841 static void cleanup_ptr()
1842 {
1843 delete [] global_ptr;
1844 global_ptr = 0;
1845 }
1846
1847 void init_ptr()
1848 {
1849 global_ptr = new int[100]; // allocate data
1850 <a href="#qAddPostRoutine">qAddPostRoutine</a>( cleanup_ptr ); // delete later
1851 }
1852 </pre>
1853
1854<p> Note that for an application- or module-wide cleanup,
1855<a href="#qAddPostRoutine">qAddPostRoutine</a>() is often not suitable. People have a tendency to
1856make such modules dynamically loaded, and then unload those modules
1857long before the QApplication destructor is called, for example.
1858<p> For modules and libraries, using a reference-counted initialization
1859manager or Qt' parent-child delete mechanism may be better. Here is
1860an example of a private class which uses the parent-child mechanism
1861to call a cleanup function at the right time:
1862<p> <pre>
1863 class MyPrivateInitStuff: public <a href="qobject.html">QObject</a> {
1864 private:
1865 MyPrivateInitStuff( <a href="qobject.html">QObject</a> * parent ): <a href="qobject.html">QObject</a>( parent) {
1866 // initialization goes here
1867 }
1868 MyPrivateInitStuff * p;
1869
1870 public:
1871 static MyPrivateInitStuff * initStuff( <a href="qobject.html">QObject</a> * parent ) {
1872 if ( !p )
1873 p = new MyPrivateInitStuff( parent );
1874 return p;
1875 }
1876
1877 ~MyPrivateInitStuff() {
1878 // cleanup (the "post routine") goes here
1879 }
1880 }
1881 </pre>
1882
1883<p> By selecting the right parent widget/object, this can often be made
1884to clean up the module's data at the exact right moment.
1885
1886<h3 class=fn>void <a name="qDebug"></a>qDebug ( const&nbsp;char&nbsp;*&nbsp;msg, ... )
1887</h3>
1888
1889<p>
1890<p> Prints a debug message <em>msg</em>, or calls the message handler (if it
1891has been installed).
1892<p> This function takes a format string and a list of arguments,
1893similar to the C printf() function.
1894<p> Example:
1895<pre>
1896 <a href="#qDebug">qDebug</a>( "my window handle = %x", myWidget-&gt;id() );
1897 </pre>
1898
1899<p> Under X11, the text is printed to stderr. Under Windows, the text
1900is sent to the debugger.
1901<p> <b>Warning:</b> The internal buffer is limited to 8196 bytes (including
1902the '&#92;0'-terminator).
1903<p> <b>Warning:</b> Passing (const char *)0 as argument to qDebug might lead
1904to crashes on certain platforms due to the platforms printf implementation.
1905<p> <p>See also <a href="#qWarning">qWarning</a>(), <a href="#qFatal">qFatal</a>(), <a href="#qInstallMsgHandler">qInstallMsgHandler</a>(), and <a href="debug.html">Debugging</a>.
1906
1907<h3 class=fn>void <a name="qFatal"></a>qFatal ( const&nbsp;char&nbsp;*&nbsp;msg, ... )
1908</h3>
1909
1910<p>
1911<p> Prints a fatal error message <em>msg</em> and exits, or calls the
1912message handler (if it has been installed).
1913<p> This function takes a format string and a list of arguments,
1914similar to the C printf() function.
1915<p> Example:
1916<pre>
1917 int divide( int a, int b )
1918 {
1919 if ( b == 0 ) // program error
1920 <a href="#qFatal">qFatal</a>( "divide: cannot divide by zero" );
1921 return a/b;
1922 }
1923 </pre>
1924
1925<p> Under X11, the text is printed to stderr. Under Windows, the text
1926is sent to the debugger.
1927<p> <b>Warning:</b> The internal buffer is limited to 8196 bytes (including
1928the '&#92;0'-terminator).
1929<p> <b>Warning:</b> Passing (const char *)0 as argument to qFatal might lead
1930to crashes on certain platforms due to the platforms printf implementation.
1931<p> <p>See also <a href="#qDebug">qDebug</a>(), <a href="#qWarning">qWarning</a>(), <a href="#qInstallMsgHandler">qInstallMsgHandler</a>(), and <a href="debug.html">Debugging</a>.
1932
1933<h3 class=fn>QtMsgHandler <a name="qInstallMsgHandler"></a>qInstallMsgHandler ( QtMsgHandler&nbsp;h )
1934</h3>
1935
1936<p> Installs a Qt message handler <em>h</em>. Returns a pointer to the
1937message handler previously defined.
1938<p> The message handler is a function that prints out debug messages,
1939warnings and fatal error messages. The Qt library (debug version)
1940contains hundreds of warning messages that are printed when
1941internal errors (usually invalid function arguments) occur. If you
1942implement your own message handler, you get total control of these
1943messages.
1944<p> The default message handler prints the message to the standard
1945output under X11 or to the debugger under Windows. If it is a
1946fatal message, the application aborts immediately.
1947<p> Only one message handler can be defined, since this is usually
1948done on an application-wide basis to control debug output.
1949<p> To restore the message handler, call <tt>qInstallMsgHandler(0)</tt>.
1950<p> Example:
1951<pre>
1952 #include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;
1953 #include &lt;stdio.h&gt;
1954 #include &lt;stdlib.h&gt;
1955
1956 void myMessageOutput( QtMsgType type, const char *msg )
1957 {
1958 switch ( type ) {
1959 case QtDebugMsg:
1960 fprintf( stderr, "Debug: %s\n", msg );
1961 break;
1962 case QtWarningMsg:
1963 fprintf( stderr, "Warning: %s\n", msg );
1964 break;
1965 case QtFatalMsg:
1966 fprintf( stderr, "Fatal: %s\n", msg );
1967 abort(); // deliberately core dump
1968 }
1969 }
1970
1971 int main( int argc, char **argv )
1972 {
1973 <a href="#qInstallMsgHandler">qInstallMsgHandler</a>( myMessageOutput );
1974 QApplication a( argc, argv );
1975 ...
1976 return a.<a href="#exec">exec</a>();
1977 }
1978 </pre>
1979
1980<p> <p>See also <a href="#qDebug">qDebug</a>(), <a href="#qWarning">qWarning</a>(), <a href="#qFatal">qFatal</a>(), and <a href="debug.html">Debugging</a>.
1981
1982<h3 class=fn>bool <a name="qSysInfo"></a>qSysInfo ( int&nbsp;*&nbsp;wordSize, bool&nbsp;*&nbsp;bigEndian )
1983</h3>
1984
1985<p> Obtains information about the system.
1986<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
1987machine, or to FALSE if this is a little-endian machine.
1988<p> In debug mode, this function calls <a href="#qFatal">qFatal</a>() with a message if the
1989computer is truly weird (i.e. different endianness for 16 bit and
199032 bit integers); in release mode it returns FALSE.
1991
1992<h3 class=fn>void <a name="qSystemWarning"></a>qSystemWarning ( const&nbsp;char&nbsp;*&nbsp;msg, int&nbsp;code )
1993</h3>
1994
1995<p> Prints the message <em>msg</em> and uses <em>code</em> to get a system specific
1996error message. When <em>code</em> is -1 (the default), the system's last
1997error code will be used if possible. Use this method to handle
1998failures in platform specific API calls.
1999<p> This function does nothing when Qt is built with <tt>QT_NO_DEBUG</tt>
2000defined.
2001
2002<h3 class=fn>const char * <a name="qVersion"></a>qVersion ()
2003</h3>
2004
2005<p> Returns the Qt version number as a string, for example, "2.3.0" or
2006"3.0.5".
2007<p> The <tt>QT_VERSION</tt> define has the numeric value in the form:
20080xmmiibb (m = major, i = minor, b = bugfix). For example, Qt
20093.0.5's <tt>QT_VERSION</tt> is 0x030005.
2010
2011<h3 class=fn>void <a name="qWarning"></a>qWarning ( const&nbsp;char&nbsp;*&nbsp;msg, ... )
2012</h3>
2013
2014<p>
2015<p> Prints a warning message <em>msg</em>, or calls the message handler (if
2016it has been installed).
2017<p> This function takes a format string and a list of arguments,
2018similar to the C printf() function.
2019<p> Example:
2020<pre>
2021 void f( int c )
2022 {
2023 if ( c &gt; 200 )
2024 <a href="#qWarning">qWarning</a>( "f: bad argument, c == %d", c );
2025 }
2026 </pre>
2027
2028<p> Under X11, the text is printed to stderr. Under Windows, the text
2029is sent to the debugger.
2030<p> <b>Warning:</b> The internal buffer is limited to 8196 bytes (including
2031the '&#92;0'-terminator).
2032<p> <b>Warning:</b> Passing (const char *)0 as argument to qWarning might lead
2033to crashes on certain platforms due to the platforms printf implementation.
2034<p> <p>See also <a href="#qDebug">qDebug</a>(), <a href="#qFatal">qFatal</a>(), <a href="#qInstallMsgHandler">qInstallMsgHandler</a>(), and <a href="debug.html">Debugging</a>.
2035
2036<!-- eof -->
2037<hr><p>
2038This file is part of the <a href="index.html">Qt toolkit</a>.
2039Copyright &copy; 1995-2007
2040<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
2041<table width=100% cellspacing=0 border=0><tr>
2042<td>Copyright &copy; 2007
2043<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
2044<td align=right><div align=right>Qt 3.3.8</div>
2045</table></div></address></body>
2046</html>
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