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1 \section{\class{wxApp}}\label{wxapp}
2
3 The {\bf wxApp} class represents the application itself. It is used
4 to:
5
6 \begin{itemize}\itemsep=0pt
7 \item set and get application-wide properties;
8 \item implement the windowing system message or event loop;
9 \item initiate application processing via \helpref{wxApp::OnInit}{wxapponinit};
10 \item allow default processing of events not handled by other
11 objects in the application.
12 \end{itemize}
13
14 You should use the macro IMPLEMENT\_APP(appClass) in your application implementation
15 file to tell wxWindows how to create an instance of your application class.
16
17 Use DECLARE\_APP(appClass) in a header file if you want the wxGetApp function (which returns
18 a reference to your application object) to be visible to other files.
19
20 \wxheading{Derived from}
21
22 \helpref{wxEvtHandler}{wxevthandler}\\
23 \helpref{wxObject}{wxobject}
24
25 \wxheading{Include files}
26
27 <wx/app.h>
28
29 \wxheading{See also}
30
31 \helpref{wxApp overview}{wxappoverview}
32
33 \latexignore{\rtfignore{\wxheading{Members}}}
34
35 \membersection{wxApp::wxApp}
36
37 \func{void}{wxApp}{\void}
38
39 Constructor. Called implicitly with a definition of a wxApp object.
40
41 \membersection{wxApp::\destruct{wxApp}}
42
43 \func{void}{\destruct{wxApp}}{\void}
44
45 Destructor. Will be called implicitly on program exit if the wxApp
46 object is created on the stack.
47
48 \membersection{wxApp::argc}\label{wxappargc}
49
50 \member{int}{argc}
51
52 Number of command line arguments (after environment-specific processing).
53
54 \membersection{wxApp::argv}\label{wxappargv}
55
56 \member{char **}{argv}
57
58 Command line arguments (after environment-specific processing).
59
60 \membersection{wxApp::CreateLogTarget}\label{wxappcreatelogtarget}
61
62 \func{virtual wxLog*}{CreateLogTarget}{\void}
63
64 Creates a wxLog class for the application to use for logging errors. The default
65 implementation returns a new wxLogGui class.
66
67 \wxheading{See also}
68
69 \helpref{wxLog}{wxlog}
70
71 \membersection{wxApp::Dispatch}\label{wxappdispatch}
72
73 \func{void}{Dispatch}{\void}
74
75 Dispatches the next event in the windowing system event queue.
76
77 This can be used for programming event loops, e.g.
78
79 \begin{verbatim}
80 while (app.Pending())
81 Dispatch();
82 \end{verbatim}
83
84 \wxheading{See also}
85
86 \helpref{wxApp::Pending}{wxapppending}
87
88 \membersection{wxApp::FilterEvent}\label{wxappfilterevent}
89
90 \func{int}{FilterEvent}{\param{wxEvent\& }{event}}
91
92 This function is called before processing any event and allows the application
93 to preempt the processing of some events. If this method returns $-1$ the event
94 is processed normally, otherwise either {\tt true} or {\tt false} should be
95 returned and the event processing stops immediately considering that the event
96 had been already processed (for the former return value) or that it is not
97 going to be processed at all (for the latter one).
98
99 \membersection{wxApp::GetAppName}\label{wxappgetappname}
100
101 \constfunc{wxString}{GetAppName}{\void}
102
103 Returns the application name.
104
105 \wxheading{Remarks}
106
107 wxWindows sets this to a reasonable default before
108 calling \helpref{wxApp::OnInit}{wxapponinit}, but the application can reset it at will.
109
110 \membersection{wxApp::GetAuto3D}\label{wxappgetauto3d}
111
112 \constfunc{bool}{GetAuto3D}{\void}
113
114 Returns true if 3D control mode is on, false otherwise.
115
116 \wxheading{See also}
117
118 \helpref{wxApp::SetAuto3D}{wxappsetauto3d}
119
120 \membersection{wxApp::GetClassName}\label{wxappgetclassname}
121
122 \constfunc{wxString}{GetClassName}{\void}
123
124 Gets the class name of the application. The class name may be used in a platform specific
125 manner to refer to the application.
126
127 \wxheading{See also}
128
129 \helpref{wxApp::SetClassName}{wxappsetclassname}
130
131 \membersection{wxApp::GetExitOnFrameDelete}\label{wxappgetexitonframedelete}
132
133 \constfunc{bool}{GetExitOnFrameDelete}{\void}
134
135 Returns true if the application will exit when the top-level window is deleted, false
136 otherwise.
137
138 \wxheading{See also}
139
140 \helpref{wxApp::SetExitOnFrameDelete}{wxappsetexitonframedelete},\\
141 \helpref{wxApp shutdown overview}{wxappshutdownoverview}
142
143 \membersection{wxApp::GetTopWindow}\label{wxappgettopwindow}
144
145 \constfunc{virtual wxWindow *}{GetTopWindow}{\void}
146
147 Returns a pointer to the top window.
148
149 \wxheading{Remarks}
150
151 If the top window hasn't been set using \helpref{wxApp::SetTopWindow}{wxappsettopwindow}, this
152 function will find the first top-level window (frame or dialog) and return that.
153
154 \wxheading{See also}
155
156 \helpref{SetTopWindow}{wxappsettopwindow}
157
158 \membersection{wxApp::GetUseBestVisual}\label{wxappgetusebestvisual}
159
160 \constfunc{bool}{GetUseBestVisual}{\void}
161
162 Returns true if the application will use the best visual on systems that support
163 different visuals, false otherwise.
164
165 \wxheading{See also}
166
167 \helpref{SetUseBestVisual}{wxappsetusebestvisual}
168
169 \membersection{wxApp::GetVendorName}\label{wxappgetvendorname}
170
171 \constfunc{wxString}{GetVendorName}{\void}
172
173 Returns the application's vendor name.
174
175 \membersection{wxApp::ExitMainLoop}\label{wxappexitmainloop}
176
177 \func{void}{ExitMainLoop}{\void}
178
179 Call this to explicitly exit the main message (event) loop.
180 You should normally exit the main loop (and the application) by deleting
181 the top window.
182
183 \membersection{wxApp::Initialized}\label{wxappinitialized}
184
185 \func{bool}{Initialized}{\void}
186
187 Returns true if the application has been initialized (i.e. if\rtfsp
188 \helpref{wxApp::OnInit}{wxapponinit} has returned successfully). This can be useful for error
189 message routines to determine which method of output is best for the
190 current state of the program (some windowing systems may not like
191 dialogs to pop up before the main loop has been entered).
192
193 \membersection{wxApp::MainLoop}\label{wxappmainloop}
194
195 \func{int}{MainLoop}{\void}
196
197 Called by wxWindows on creation of the application. Override this if you wish
198 to provide your own (environment-dependent) main loop.
199
200 \wxheading{Return value}
201
202 Returns 0 under X, and the wParam of the WM\_QUIT message under Windows.
203
204 %% VZ: OnXXX() functions should *not* be documented
205 %%
206 %%\membersection{wxApp::OnActivate}\label{wxapponactivate}
207 %%
208 %%\func{void}{OnActivate}{\param{wxActivateEvent\& }{event}}
209 %%
210 %%Provide this member function to know whether the application is being
211 %%activated or deactivated (Windows only).
212 %%
213 %%\wxheading{See also}
214 %%
215 %%\helpref{wxWindow::OnActivate}{wxwindowonactivate}, \helpref{wxActivateEvent}{wxactivateevent}
216 %%
217 %%\membersection{wxApp::OnCharHook}\label{wxapponcharhook}
218 %%
219 %%\func{void}{OnCharHook}{\param{wxKeyEvent\&}{ event}}
220 %%
221 %%This event handler function is called (under Windows only) to allow the window to intercept keyboard events
222 %%before they are processed by child windows.
223 %%
224 %%\wxheading{Parameters}
225 %%
226 %%\docparam{event}{The keypress event.}
227 %%
228 %%\wxheading{Remarks}
229 %%
230 %%Use the wxEVT\_CHAR\_HOOK macro in your event table.
231 %%
232 %%If you use this member, you can selectively consume keypress events by calling\rtfsp
233 %%\helpref{wxEvent::Skip}{wxeventskip} for characters the application is not interested in.
234 %%
235 %%\wxheading{See also}
236 %%
237 %%\helpref{wxKeyEvent}{wxkeyevent}, \helpref{wxWindow::OnChar}{wxwindowonchar},\rtfsp
238 %%\helpref{wxWindow::OnCharHook}{wxwindowoncharhook}, \helpref{wxDialog::OnCharHook}{wxdialogoncharhook}
239
240 \membersection{wxApp::OnAssert}\label{wxapponassert}
241
242 \func{void}{OnAssert}{\param{const wxChar }{*file}, \param{int }{line}, \param{const wxChar }{*cond}, \param{const wxChar }{*msg}}
243
244 This function is called when an assert failure occurs, i.e. the condition
245 specified in \helpref{wxASSERT}{wxassert} macro evaluated to {\tt false}.
246 It is only called in debug mode (when {\tt \_\_WXDEBUG\_\_} is defined) as
247 asserts are not left in the release code at all.
248
249 The base class version show the default assert failure dialog box proposing to
250 the user to stop the program, continue or ignore all subsequent asserts.
251
252 \wxheading{Parameters}
253
254 \docparam{file}{the name of the source file where the assert occured}
255
256 \docparam{line}{the line number in this file where the assert occured}
257
258 \docparam{cond}{the condition of the failed assert in string form}
259
260 \docparam{msg}{the message specified as argument to
261 \helpref{wxASSERT\_MSG}{wxassertmsg} or \helpref{wxFAIL\_MSG}{wxfailmsg}, will
262 be {\tt NULL} if just \helpref{wxASSERT}{wxassert} or \helpref{wxFAIL}{wxfail}
263 was used}
264
265 \membersection{wxApp::OnExit}\label{wxapponexit}
266
267 \func{int}{OnExit}{\void}
268
269 Provide this member function for any processing which needs to be
270 done as the application is about to exit. OnExit is called after
271 destroying all application windows and controls, but before
272 wxWindows cleanup.
273
274 \membersection{wxApp::OnCmdLineError}\label{wxapponcmdlineerror}
275
276 \func{bool}{OnCmdLineError}{\param{wxCmdLineParser\& }{parser}}
277
278 Called when command line parsing fails (i.e. an incorrect command line option
279 was specified by the user). The default behaviour is to show the program usage
280 text and abort the program.
281
282 Return {\tt true} to continue normal execution or {\tt false} to return
283 {\tt false} from \helpref{OnInit}{wxapponinit} thus terminating the program.
284
285 \wxheading{See also}
286
287 \helpref{OnInitCmdLine}{wxapponinitcmdline}
288
289 \membersection{wxApp::OnCmdLineHelp}\label{wxapponcmdlinehelp}
290
291 \func{bool}{OnCmdLineHelp}{\param{wxCmdLineParser\& }{parser}}
292
293 Called when the help option ({\tt --help}) was specified on the command line.
294 The default behaviour is to show the program usage text and abort the program.
295
296 Return {\tt true} to continue normal execution or {\tt false} to return
297 {\tt false} from \helpref{OnInit}{wxapponinit} thus terminating the program.
298
299 \wxheading{See also}
300
301 \helpref{OnInitCmdLine}{wxapponinitcmdline}
302
303 \membersection{wxApp::OnCmdLineParsed}\label{wxapponcmdlineparsed}
304
305 \func{bool}{OnCmdLineParsed}{\param{wxCmdLineParser\& }{parser}}
306
307 Called after the command line had been successfully parsed. You may override
308 this method to test for the values of the various parameters which could be
309 set from the command line.
310
311 Don't forget to call the base class version unless you want to suppress
312 processing of the standard command line options.
313
314 Return {\tt true} to continue normal execution or {\tt false} to return
315 {\tt false} from \helpref{OnInit}{wxapponinit} thus terminating the program.
316
317 \wxheading{See also}
318
319 \helpref{OnInitCmdLine}{wxapponinitcmdline}
320
321 \membersection{wxApp::OnFatalException}\label{wxapponfatalexception}
322
323 \func{void}{OnFatalException}{\void}
324
325 This function may be called if something fatal happens: an unhandled
326 exception under Win32 or a a fatal signal under Unix, for example. However,
327 this will not happen by default: you have to explicitly call
328 \helpref{wxHandleFatalExceptions}{wxhandlefatalexceptions} to enable this.
329
330 Generally speaking, this function should only show a message to the user and
331 return. You may attempt to save unsaved data but this is not guaranteed to
332 work and, in fact, probably won't.
333
334 \wxheading{See also}
335
336 \helpref{wxHandleFatalExcetions}{wxhandlefatalexceptions}
337
338 %% VZ: the wxApp event handler are private and should not be documented here!
339 %%
340 %%\membersection{wxApp::OnIdle}\label{wxapponidle}
341 %%
342 %%\func{void}{OnIdle}{\param{wxIdleEvent\& }{event}}
343 %%
344 %%Override this member function for any processing which needs to be done
345 %%when the application is idle. You should call wxApp::OnIdle from your own function,
346 %%since this forwards OnIdle events to windows and also performs garbage collection for
347 %%windows whose destruction has been delayed.
348 %%
349 %%wxWindows' strategy for OnIdle processing is as follows. After pending user interface events for an
350 %%application have all been processed, wxWindows sends an OnIdle event to the application object. wxApp::OnIdle itself
351 %%sends an OnIdle event to each application window, allowing windows to do idle processing such as updating
352 %%their appearance. If either wxApp::OnIdle or a window OnIdle function requested more time, by
353 %%calling \helpref{wxIdleEvent::RequestMore}{wxidleeventrequestmore}, wxWindows will send another OnIdle
354 %%event to the application object. This will occur in a loop until either a user event is found to be
355 %%pending, or OnIdle requests no more time. Then all pending user events are processed until the system
356 %%goes idle again, when OnIdle is called, and so on.
357 %%
358 %%\wxheading{See also}
359 %%
360 %%\helpref{wxWindow::OnIdle}{wxwindowonidle}, \helpref{wxIdleEvent}{wxidleevent},\rtfsp
361 %%\helpref{wxWindow::SendIdleEvents}{wxappsendidleevents}
362 %%
363 %%\membersection{wxApp::OnEndSession}\label{wxapponendsession}
364 %%
365 %%\func{void}{OnEndSession}{\param{wxCloseEvent\& }{event}}
366 %%
367 %%This is an event handler function called when the operating system or GUI session is
368 %%about to close down. The application has a chance to silently save information,
369 %%and can optionally close itself.
370 %%
371 %%Use the EVT\_END\_SESSION event table macro to handle query end session events.
372 %%
373 %%The default handler calls \helpref{wxWindow::Close}{wxwindowclose} with a true argument
374 %%(forcing the application to close itself silently).
375 %%
376 %%\wxheading{Remarks}
377 %%
378 %%Under X, OnEndSession is called in response to the `die' event.
379 %%
380 %%Under Windows, OnEndSession is called in response to the WM\_ENDSESSION message.
381 %%
382 %%\wxheading{See also}
383 %%
384 %%\helpref{wxWindow::Close}{wxwindowclose},\rtfsp
385 %%\helpref{wxWindow::OnCloseWindow}{wxwindowonclosewindow},\rtfsp
386 %%\helpref{wxCloseEvent}{wxcloseevent},\rtfsp
387 %%\helpref{wxApp::OnQueryEndSession}{wxapponqueryendsession}
388
389 \membersection{wxApp::OnInit}\label{wxapponinit}
390
391 \func{bool}{OnInit}{\void}
392
393 This must be provided by the application, and will usually create the
394 application's main window, optionally calling
395 \helpref{wxApp::SetTopWindow}{wxappsettopwindow}.
396
397 Notice that if you want to to use the command line processing provided by
398 wxWindows you have to call the base class version in the derived class
399 OnInit().
400
401 Return true to continue processing, false to exit the application.
402
403 \membersection{wxApp::OnInitCmdLine}\label{wxapponinitcmdline}
404
405 \func{void}{OnInitCmdLine}{\param{wxCmdLineParser\& }{parser}}
406
407 Called from \helpref{OnInit}{wxapponinit} and may be used to initialize the
408 parser with the command line options for this application. The base class
409 versions adds support for a few standard options only.
410
411 \membersection{wxApp::OnQueryEndSession}\label{wxapponqueryendsession}
412
413 \func{void}{OnQueryEndSession}{\param{wxCloseEvent\& }{event}}
414
415 This is an event handler function called when the operating system or GUI session is
416 about to close down. Typically, an application will try to save unsaved documents
417 at this point.
418
419 If \helpref{wxCloseEvent::CanVeto}{wxcloseeventcanveto} returns true, the application
420 is allowed to veto the shutdown by calling \helpref{wxCloseEvent::Veto}{wxcloseeventveto}.
421 The application might veto the shutdown after prompting for documents to be saved, and the
422 user has cancelled the save.
423
424 Use the EVT\_QUERY\_END\_SESSION event table macro to handle query end session events.
425
426 You should check whether the application is forcing the deletion of the window
427 using \helpref{wxCloseEvent::GetForce}{wxcloseeventgetforce}. If this is true,
428 destroy the window using \helpref{wxWindow::Destroy}{wxwindowdestroy}.
429 If not, it is up to you whether you respond by destroying the window.
430
431 The default handler calls \helpref{wxWindow::Close}{wxwindowclose} on the top-level window,
432 and vetoes the shutdown if Close returns false. This will be sufficient for many applications.
433
434 \wxheading{Remarks}
435
436 Under X, OnQueryEndSession is called in response to the `save session' event.
437
438 Under Windows, OnQueryEndSession is called in response to the WM\_QUERYENDSESSION message.
439
440 \wxheading{See also}
441
442 \helpref{wxWindow::Close}{wxwindowclose},\rtfsp
443 \helpref{wxCloseEvent}{wxcloseevent}
444 %% GD: OnXXX functions are not documented
445 %%\helpref{wxApp::OnEndSession}{wxapponendsession}
446
447 \membersection{wxApp::ProcessMessage}\label{wxappprocessmessage}
448
449 \func{bool}{ProcessMessage}{\param{WXMSG *}{msg}}
450
451 Windows-only function for processing a message. This function
452 is called from the main message loop, checking for windows that
453 may wish to process it. The function returns true if the message
454 was processed, false otherwise. If you use wxWindows with another class
455 library with its own message loop, you should make sure that this
456 function is called to allow wxWindows to receive messages. For example,
457 to allow co-existence with the Microsoft Foundation Classes, override
458 the PreTranslateMessage function:
459
460 \begin{verbatim}
461 // Provide wxWindows message loop compatibility
462 BOOL CTheApp::PreTranslateMessage(MSG *msg)
463 {
464 if (wxTheApp && wxTheApp->ProcessMessage((WXMSW *)msg))
465 return true;
466 else
467 return CWinApp::PreTranslateMessage(msg);
468 }
469 \end{verbatim}
470
471 \membersection{wxApp::Pending}\label{wxapppending}
472
473 \func{bool}{Pending}{\void}
474
475 Returns true if unprocessed events are in the window system event queue.
476
477 \wxheading{See also}
478
479 \helpref{wxApp::Dispatch}{wxappdispatch}
480
481 \membersection{wxApp::SendIdleEvents}\label{wxappsendidleevents}
482
483 \func{bool}{SendIdleEvents}{\void}
484
485 Sends idle events to all top-level windows.
486
487 \func{bool}{SendIdleEvents}{\param{wxWindow*}{ win}}
488
489 Sends idle events to a window and its children.
490
491 \wxheading{Remarks}
492
493 These functions poll the top-level windows, and their children, for idle event processing.
494 If true is returned, more OnIdle processing is requested by one or more window.
495
496 \wxheading{See also}
497
498 %% GD: OnXXX functions are not documented
499 %%\helpref{wxApp::OnIdle}{wxapponidle}
500 \helpref{wxIdleEvent}{wxidleevent}
501
502 \membersection{wxApp::SetAppName}\label{wxappsetappname}
503
504 \func{void}{SetAppName}{\param{const wxString\& }{name}}
505
506 Sets the name of the application. The name may be used in dialogs
507 (for example by the document/view framework). A default name is set by
508 wxWindows.
509
510 \wxheading{See also}
511
512 \helpref{wxApp::GetAppName}{wxappgetappname}
513
514 \membersection{wxApp::SetAuto3D}\label{wxappsetauto3d}
515
516 \func{void}{SetAuto3D}{\param{const bool}{ auto3D}}
517
518 Switches automatic 3D controls on or off.
519
520 \wxheading{Parameters}
521
522 \docparam{auto3D}{If true, all controls will be created with 3D appearances unless
523 overridden for a control or dialog. The default is true}
524
525 \wxheading{Remarks}
526
527 This has an effect on Windows only.
528
529 \wxheading{See also}
530
531 \helpref{wxApp::GetAuto3D}{wxappgetauto3d}
532
533 \membersection{wxApp::SetClassName}\label{wxappsetclassname}
534
535 \func{void}{SetClassName}{\param{const wxString\& }{name}}
536
537 Sets the class name of the application. This may be used in a platform specific
538 manner to refer to the application.
539
540 \wxheading{See also}
541
542 \helpref{wxApp::GetClassName}{wxappgetclassname}
543
544 \membersection{wxApp::SetExitOnFrameDelete}\label{wxappsetexitonframedelete}
545
546 \func{void}{SetExitOnFrameDelete}{\param{bool}{ flag}}
547
548 Allows the programmer to specify whether the application will exit when the
549 top-level frame is deleted.
550
551 \wxheading{Parameters}
552
553 \docparam{flag}{If true (the default), the application will exit when the top-level frame is
554 deleted. If false, the application will continue to run.}
555
556 \wxheading{See also}
557
558 \helpref{wxApp::GetExitOnFrameDelete}{wxappgetexitonframedelete},\\
559 \helpref{wxApp shutdown overview}{wxappshutdownoverview}
560
561 \membersection{wxApp::SetTopWindow}\label{wxappsettopwindow}
562
563 \func{void}{SetTopWindow}{\param{wxWindow* }{window}}
564
565 Sets the `top' window. You can call this from within \helpref{wxApp::OnInit}{wxapponinit} to
566 let wxWindows know which is the main window. You don't have to set the top window;
567 it is only a convenience so that (for example) certain dialogs without parents can use a
568 specific window as the top window. If no top window is specified by the application,
569 wxWindows just uses the first frame or dialog in its top-level window list, when it
570 needs to use the top window.
571
572 \wxheading{Parameters}
573
574 \docparam{window}{The new top window.}
575
576 \wxheading{See also}
577
578 \helpref{wxApp::GetTopWindow}{wxappgettopwindow}, \helpref{wxApp::OnInit}{wxapponinit}
579
580
581 \membersection{wxApp::SetVendorName}\label{wxappsetvendorname}
582
583 \func{void}{SetVendorName}{\param{const wxString\& }{name}}
584
585 Sets the name of application's vendor. The name will be used
586 in registry access. A default name is set by
587 wxWindows.
588
589 \wxheading{See also}
590
591 \helpref{wxApp::GetVendorName}{wxappgetvendorname}
592
593 \membersection{wxApp::SetUseBestVisual}\label{wxappsetusebestvisual}
594
595 \func{void}{SetUseBestVisual}{\param{bool}{ flag}}
596
597 Allows the programmer to specify whether the application will use the best visual
598 on systems that support several visual on the same display. This is typically the
599 case under Solaris and IRIX, where the default visual is only 8-bit whereas certain
600 applications are supposed to run in TrueColour mode.
601
602 Note that this function has to be called in the constructor of the {\tt wxApp}
603 instance and won't have any effect when called later on.
604
605 This function currently only has effect under GTK.
606
607 \wxheading{Parameters}
608
609 \docparam{flag}{If true, the app will use the best visual.}
610
611 \membersection{wxApp::Yield}\label{wxappyield}
612
613 \func{bool}{Yield}{\param{bool}{ onlyIfNeeded = false}}
614
615 Yields control to pending messages in the windowing system. This can be useful, for example, when a
616 time-consuming process writes to a text window. Without an occasional
617 yield, the text window will not be updated properly, and on systems with
618 cooperative multitasking, such as Windows 3.1 other processes will not respond.
619
620 Caution should be exercised, however, since yielding may allow the
621 user to perform actions which are not compatible with the current task.
622 Disabling menu items or whole menus during processing can avoid unwanted
623 reentrance of code: see \helpref{::wxSafeYield}{wxsafeyield} for a better
624 function.
625
626 Note that Yield() will not flush the message logs. This is intentional as
627 calling Yield() is usually done to quickly update the screen and popping up a
628 message box dialog may be undesirable. If you do wish to flush the log
629 messages immediately (otherwise it will be done during the next idle loop
630 iteration), call \helpref{wxLog::FlushActive}{wxlogflushactive}.
631
632 Calling Yield() recursively is normally an error and an assert failure is
633 raised in debug build if such situation is detected. However if the the
634 {\it onlyIfNeeded} parameter is {\tt true}, the method will just silently
635 return {\tt false} instead.
636