src/common/appbase.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        common/base/appbase.cpp
   3 // Purpose:     implements wxAppConsole class
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     19.06.2003 (extracted from common/appcmn.cpp)
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
   9 // License:     wxWindows license
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // for compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 #ifndef WX_PRECOMP
  28     #include "wx/app.h"
  29     #include "wx/intl.h"
  30     #include "wx/list.h"
  31     #include "wx/log.h"
  32 #endif //WX_PRECOMP
  33
  34 #include "wx/utils.h"
  35 #include "wx/apptrait.h"
  36 #include "wx/cmdline.h"
  37 #include "wx/confbase.h"
  38 #include "wx/filename.h"
  39 #include "wx/msgout.h"
  40 #include "wx/tokenzr.h"
  41
  42 #if !defined(__WXMSW__) || defined(__WXMICROWIN__)
  43   #include  <signal.h>      // for SIGTRAP used by wxTrap()
  44 #endif  //Win/Unix
  45
  46 #if defined(__WXMSW__)
  47   #include  "wx/msw/wrapwin.h"  // includes windows.h for MessageBox()
  48 #endif
  49
  50 #if wxUSE_FONTMAP
  51     #include "wx/fontmap.h"
  52 #endif // wxUSE_FONTMAP
  53
  54 #if defined(__DARWIN__) && defined(_MSL_USING_MW_C_HEADERS) && _MSL_USING_MW_C_HEADERS
  55     // For MacTypes.h for Debugger function
  56     #include <CoreFoundation/CFBase.h>
  57 #endif
  58
  59 #if defined(__WXMAC__)
  60     // VZ: MacTypes.h is enough under Mac OS X (where I could test it) but
  61     //     I don't know which headers are needed under earlier systems so
  62     //     include everything when in doubt
  63     #ifdef __DARWIN__
  64         #include  "MacTypes.h"
  65     #else
  66         #include  "wx/mac/private.h"  // includes mac headers
  67     #endif
  68 #endif // __WXMAC__
  69
  70 #ifdef __WXDEBUG__
  71     #ifdef wxUSE_STACKWALKER
  72         #include "wx/stackwalk.h"
  73     #endif // wxUSE_STACKWALKER
  74 #endif // __WXDEBUG__
  75
  76 // ----------------------------------------------------------------------------
  77 // private functions prototypes
  78 // ----------------------------------------------------------------------------
  79
  80 #ifdef __WXDEBUG__
  81     // really just show the assert dialog
  82     static bool DoShowAssertDialog(const wxString& msg);
  83
  84     // prepare for showing the assert dialog, use the given traits or
  85     // DoShowAssertDialog() as last fallback to really show it
  86     static
  87     void ShowAssertDialog(const wxChar *szFile,
  88                           int nLine,
  89                           const wxChar *szCond,
  90                           const wxChar *szMsg,
  91                           wxAppTraits *traits = NULL);
  92
  93     // turn on the trace masks specified in the env variable WXTRACE
  94     static void LINKAGEMODE SetTraceMasks();
  95 #endif // __WXDEBUG__
  96
  97 // ----------------------------------------------------------------------------
  98 // global vars
  99 // ----------------------------------------------------------------------------
 100
 101 wxAppConsole *wxAppConsole::ms_appInstance = NULL;
 102
 103 wxAppInitializerFunction wxAppConsole::ms_appInitFn = NULL;
 104
 105 // ============================================================================
 106 // wxAppConsole implementation
 107 // ============================================================================
 108
 109 // ----------------------------------------------------------------------------
 110 // ctor/dtor
 111 // ----------------------------------------------------------------------------
 112
 113 wxAppConsole::wxAppConsole()
 114 {
 115     m_traits = NULL;
 116
 117     ms_appInstance = this;
 118
 119 #ifdef __WXDEBUG__
 120     SetTraceMasks();
 121 #if wxUSE_UNICODE
 122     // In unicode mode the SetTraceMasks call can cause an apptraits to be
 123     // created, but since we are still in the constructor the wrong kind will
 124     // be created for GUI apps.  Destroy it so it can be created again later.
 125     delete m_traits;
 126     m_traits = NULL;
 127 #endif
 128 #endif
 129 }
 130
 131 wxAppConsole::~wxAppConsole()
 132 {
 133     delete m_traits;
 134 }
 135
 136 // ----------------------------------------------------------------------------
 137 // initilization/cleanup
 138 // ----------------------------------------------------------------------------
 139
 140 bool wxAppConsole::Initialize(int& argc, wxChar **argv)
 141 {
 142 #if wxUSE_LOG
 143     // If some code logged something before wxApp instance was created,
 144     // wxLogStderr was set as the target. Undo it here by destroying the
 145     // current target. It will be re-created next time logging is needed, but
 146     // this time wxAppTraits will be used:
 147     delete wxLog::SetActiveTarget(NULL);
 148 #endif // wxUSE_LOG
 149
 150     // remember the command line arguments
 151     this->argc = argc;
 152     this->argv = argv;
 153
 154 #ifndef __WXPALMOS__
 155     if ( m_appName.empty() && argv )
 156     {
 157         // the application name is, by default, the name of its executable file
 158         wxFileName::SplitPath(argv[0], NULL, &m_appName, NULL);
 159     }
 160 #endif
 161
 162     return true;
 163 }
 164
 165 void wxAppConsole::CleanUp()
 166 {
 167 }
 168
 169 // ----------------------------------------------------------------------------
 170 // OnXXX() callbacks
 171 // ----------------------------------------------------------------------------
 172
 173 bool wxAppConsole::OnInit()
 174 {
 175 #if wxUSE_CMDLINE_PARSER
 176     wxCmdLineParser parser(argc, argv);
 177
 178     OnInitCmdLine(parser);
 179
 180     bool cont;
 181     switch ( parser.Parse(false /* don't show usage */) )
 182     {
 183         case -1:
 184             cont = OnCmdLineHelp(parser);
 185             break;
 186
 187         case 0:
 188             cont = OnCmdLineParsed(parser);
 189             break;
 190
 191         default:
 192             cont = OnCmdLineError(parser);
 193             break;
 194     }
 195
 196     if ( !cont )
 197         return false;
 198 #endif // wxUSE_CMDLINE_PARSER
 199
 200     return true;
 201 }
 202
 203 int wxAppConsole::OnExit()
 204 {
 205 #if wxUSE_CONFIG
 206     // delete the config object if any (don't use Get() here, but Set()
 207     // because Get() could create a new config object)
 208     delete wxConfigBase::Set((wxConfigBase *) NULL);
 209 #endif // wxUSE_CONFIG
 210
 211     // use Set(NULL) and not Get() to avoid creating a message output object on
 212     // demand when we just want to delete it
 213     delete wxMessageOutput::Set(NULL);
 214
 215     return 0;
 216 }
 217
 218 void wxAppConsole::Exit()
 219 {
 220     exit(-1);
 221 }
 222
 223 // ----------------------------------------------------------------------------
 224 // traits stuff
 225 // ----------------------------------------------------------------------------
 226
 227 wxAppTraits *wxAppConsole::CreateTraits()
 228 {
 229     return new wxConsoleAppTraits;
 230 }
 231
 232 wxAppTraits *wxAppConsole::GetTraits()
 233 {
 234     // FIXME-MT: protect this with a CS?
 235     if ( !m_traits )
 236     {
 237         m_traits = CreateTraits();
 238
 239         wxASSERT_MSG( m_traits, _T("wxApp::CreateTraits() failed?") );
 240     }
 241
 242     return m_traits;
 243 }
 244
 245 // we must implement CreateXXX() in wxApp itself for backwards compatibility
 246 #if WXWIN_COMPATIBILITY_2_4
 247
 248 #if wxUSE_LOG
 249
 250 wxLog *wxAppConsole::CreateLogTarget()
 251 {
 252     wxAppTraits *traits = GetTraits();
 253     return traits ? traits->CreateLogTarget() : NULL;
 254 }
 255
 256 #endif // wxUSE_LOG
 257
 258 wxMessageOutput *wxAppConsole::CreateMessageOutput()
 259 {
 260     wxAppTraits *traits = GetTraits();
 261     return traits ? traits->CreateMessageOutput() : NULL;
 262 }
 263
 264 #endif // WXWIN_COMPATIBILITY_2_4
 265
 266 // ----------------------------------------------------------------------------
 267 // event processing
 268 // ----------------------------------------------------------------------------
 269
 270 void wxAppConsole::ProcessPendingEvents()
 271 {
 272 #if wxUSE_THREADS
 273     if ( !wxPendingEventsLocker )
 274         return;
 275 #endif
 276
 277     // ensure that we're the only thread to modify the pending events list
 278     wxENTER_CRIT_SECT( *wxPendingEventsLocker );
 279
 280     if ( !wxPendingEvents )
 281     {
 282         wxLEAVE_CRIT_SECT( *wxPendingEventsLocker );
 283         return;
 284     }
 285
 286     // iterate until the list becomes empty
 287     wxList::compatibility_iterator node = wxPendingEvents->GetFirst();
 288     while (node)
 289     {
 290         wxEvtHandler *handler = (wxEvtHandler *)node->GetData();
 291         wxPendingEvents->Erase(node);
 292
 293         // In ProcessPendingEvents(), new handlers might be add
 294         // and we can safely leave the critical section here.
 295         wxLEAVE_CRIT_SECT( *wxPendingEventsLocker );
 296
 297         handler->ProcessPendingEvents();
 298
 299         wxENTER_CRIT_SECT( *wxPendingEventsLocker );
 300
 301         node = wxPendingEvents->GetFirst();
 302     }
 303
 304     wxLEAVE_CRIT_SECT( *wxPendingEventsLocker );
 305 }
 306
 307 int wxAppConsole::FilterEvent(wxEvent& WXUNUSED(event))
 308 {
 309     // process the events normally by default
 310     return -1;
 311 }
 312
 313 // ----------------------------------------------------------------------------
 314 // exception handling
 315 // ----------------------------------------------------------------------------
 316
 317 #if wxUSE_EXCEPTIONS
 318
 319 void
 320 wxAppConsole::HandleEvent(wxEvtHandler *handler,
 321                           wxEventFunction func,
 322                           wxEvent& event) const
 323 {
 324     // by default, simply call the handler
 325     (handler->*func)(event);
 326 }
 327
 328 bool
 329 wxAppConsole::OnExceptionInMainLoop()
 330 {
 331     throw;
 332
 333     // some compilers are too stupid to know that we never return after throw
 334 #if defined(__DMC__) || (defined(_MSC_VER) && _MSC_VER < 1200)
 335     return false;
 336 #endif
 337 }
 338
 339 #endif // wxUSE_EXCEPTIONS
 340
 341 // ----------------------------------------------------------------------------
 342 // cmd line parsing
 343 // ----------------------------------------------------------------------------
 344
 345 #if wxUSE_CMDLINE_PARSER
 346
 347 #define OPTION_VERBOSE _T("verbose")
 348
 349 void wxAppConsole::OnInitCmdLine(wxCmdLineParser& parser)
 350 {
 351     // the standard command line options
 352     static const wxCmdLineEntryDesc cmdLineDesc[] =
 353     {
 354         {
 355             wxCMD_LINE_SWITCH,
 356             _T("h"),
 357             _T("help"),
 358             gettext_noop("show this help message"),
 359             wxCMD_LINE_VAL_NONE,
 360             wxCMD_LINE_OPTION_HELP
 361         },
 362
 363 #if wxUSE_LOG
 364         {
 365             wxCMD_LINE_SWITCH,
 366             wxEmptyString,
 367             OPTION_VERBOSE,
 368             gettext_noop("generate verbose log messages"),
 369             wxCMD_LINE_VAL_NONE,
 370             0x0
 371         },
 372 #endif // wxUSE_LOG
 373
 374         // terminator
 375         {
 376             wxCMD_LINE_NONE,
 377             wxEmptyString,
 378             wxEmptyString,
 379             wxEmptyString,
 380             wxCMD_LINE_VAL_NONE,
 381             0x0
 382         }
 383     };
 384
 385     parser.SetDesc(cmdLineDesc);
 386 }
 387
 388 bool wxAppConsole::OnCmdLineParsed(wxCmdLineParser& parser)
 389 {
 390 #if wxUSE_LOG
 391     if ( parser.Found(OPTION_VERBOSE) )
 392     {
 393         wxLog::SetVerbose(true);
 394     }
 395 #else
 396     wxUnusedVar(parser);
 397 #endif // wxUSE_LOG
 398
 399     return true;
 400 }
 401
 402 bool wxAppConsole::OnCmdLineHelp(wxCmdLineParser& parser)
 403 {
 404     parser.Usage();
 405
 406     return false;
 407 }
 408
 409 bool wxAppConsole::OnCmdLineError(wxCmdLineParser& parser)
 410 {
 411     parser.Usage();
 412
 413     return false;
 414 }
 415
 416 #endif // wxUSE_CMDLINE_PARSER
 417
 418 // ----------------------------------------------------------------------------
 419 // debugging support
 420 // ----------------------------------------------------------------------------
 421
 422 /* static */
 423 bool wxAppConsole::CheckBuildOptions(const char *optionsSignature,
 424                                      const char *componentName)
 425 {
 426 #if 0 // can't use wxLogTrace, not up and running yet
 427     printf("checking build options object '%s' (ptr %p) in '%s'\n",
 428              optionsSignature, optionsSignature, componentName);
 429 #endif
 430
 431     if ( strcmp(optionsSignature, WX_BUILD_OPTIONS_SIGNATURE) != 0 )
 432     {
 433         wxString lib = wxString::FromAscii(WX_BUILD_OPTIONS_SIGNATURE);
 434         wxString prog = wxString::FromAscii(optionsSignature);
 435         wxString progName = wxString::FromAscii(componentName);
 436         wxString msg;
 437
 438         msg.Printf(_T("Mismatch between the program and library build versions detected.\nThe library used %s,\nand %s used %s."),
 439                    lib.c_str(), progName.c_str(), prog.c_str());
 440
 441         wxLogFatalError(msg.c_str());
 442
 443         // normally wxLogFatalError doesn't return
 444         return false;
 445     }
 446 #undef wxCMP
 447
 448     return true;
 449 }
 450
 451 #ifdef __WXDEBUG__
 452
 453 void wxAppConsole::OnAssert(const wxChar *file,
 454                             int line,
 455                             const wxChar *cond,
 456                             const wxChar *msg)
 457 {
 458     ShowAssertDialog(file, line, cond, msg, GetTraits());
 459 }
 460
 461 #endif // __WXDEBUG__
 462
 463 #if WXWIN_COMPATIBILITY_2_4
 464
 465 bool wxAppConsole::CheckBuildOptions(const wxBuildOptions& buildOptions)
 466 {
 467     return CheckBuildOptions(buildOptions.m_signature, "your program");
 468 }
 469
 470 #endif
 471
 472 // ============================================================================
 473 // other classes implementations
 474 // ============================================================================
 475
 476 // ----------------------------------------------------------------------------
 477 // wxConsoleAppTraitsBase
 478 // ----------------------------------------------------------------------------
 479
 480 #if wxUSE_LOG
 481
 482 wxLog *wxConsoleAppTraitsBase::CreateLogTarget()
 483 {
 484     return new wxLogStderr;
 485 }
 486
 487 #endif // wxUSE_LOG
 488
 489 wxMessageOutput *wxConsoleAppTraitsBase::CreateMessageOutput()
 490 {
 491     return new wxMessageOutputStderr;
 492 }
 493
 494 #if wxUSE_FONTMAP
 495
 496 wxFontMapper *wxConsoleAppTraitsBase::CreateFontMapper()
 497 {
 498     return (wxFontMapper *)new wxFontMapperBase;
 499 }
 500
 501 #endif // wxUSE_FONTMAP
 502
 503 wxRendererNative *wxConsoleAppTraitsBase::CreateRenderer()
 504 {
 505     // console applications don't use renderers
 506     return NULL;
 507 }
 508
 509 #ifdef __WXDEBUG__
 510 bool wxConsoleAppTraitsBase::ShowAssertDialog(const wxString& msg)
 511 {
 512     return wxAppTraitsBase::ShowAssertDialog(msg);
 513 }
 514 #endif
 515
 516 bool wxConsoleAppTraitsBase::HasStderr()
 517 {
 518     // console applications always have stderr, even under Mac/Windows
 519     return true;
 520 }
 521
 522 void wxConsoleAppTraitsBase::ScheduleForDestroy(wxObject *object)
 523 {
 524     delete object;
 525 }
 526
 527 void wxConsoleAppTraitsBase::RemoveFromPendingDelete(wxObject * WXUNUSED(object))
 528 {
 529     // nothing to do
 530 }
 531
 532 #if wxUSE_SOCKETS
 533 GSocketGUIFunctionsTable* wxConsoleAppTraitsBase::GetSocketGUIFunctionsTable()
 534 {
 535     return NULL;
 536 }
 537 #endif
 538
 539 // ----------------------------------------------------------------------------
 540 // wxAppTraits
 541 // ----------------------------------------------------------------------------
 542
 543 #ifdef __WXDEBUG__
 544
 545 bool wxAppTraitsBase::ShowAssertDialog(const wxString& msg)
 546 {
 547     return DoShowAssertDialog(msg);
 548 }
 549
 550 #endif // __WXDEBUG__
 551
 552 // ============================================================================
 553 // global functions implementation
 554 // ============================================================================
 555
 556 void wxExit()
 557 {
 558     if ( wxTheApp )
 559     {
 560         wxTheApp->Exit();
 561     }
 562     else
 563     {
 564         // what else can we do?
 565         exit(-1);
 566     }
 567 }
 568
 569 void wxWakeUpIdle()
 570 {
 571     if ( wxTheApp )
 572     {
 573         wxTheApp->WakeUpIdle();
 574     }
 575     //else: do nothing, what can we do?
 576 }
 577
 578 #ifdef  __WXDEBUG__
 579
 580 // wxASSERT() helper
 581 bool wxAssertIsEqual(int x, int y)
 582 {
 583     return x == y;
 584 }
 585
 586 // break into the debugger
 587 void wxTrap()
 588 {
 589 #if defined(__WXMSW__) && !defined(__WXMICROWIN__)
 590     DebugBreak();
 591 #elif defined(__WXMAC__) && !defined(__DARWIN__)
 592     #if __powerc
 593         Debugger();
 594     #else
 595         SysBreak();
 596     #endif
 597 #elif defined(_MSL_USING_MW_C_HEADERS) && _MSL_USING_MW_C_HEADERS
 598     Debugger();
 599 #elif defined(__UNIX__)
 600     raise(SIGTRAP);
 601 #else
 602     // TODO
 603 #endif // Win/Unix
 604 }
 605
 606 void wxAssert(int cond,
 607               const wxChar *szFile,
 608               int nLine,
 609               const wxChar *szCond,
 610               const wxChar *szMsg)
 611 {
 612     if ( !cond )
 613         wxOnAssert(szFile, nLine, szCond, szMsg);
 614 }
 615
 616 // this function is called when an assert fails
 617 void wxOnAssert(const wxChar *szFile,
 618                 int nLine,
 619                 const wxChar *szCond,
 620                 const wxChar *szMsg)
 621 {
 622     // FIXME MT-unsafe
 623     static bool s_bInAssert = false;
 624
 625     if ( s_bInAssert )
 626     {
 627         // He-e-e-e-elp!! we're trapped in endless loop
 628         wxTrap();
 629
 630         s_bInAssert = false;
 631
 632         return;
 633     }
 634
 635     s_bInAssert = true;
 636
 637     if ( !wxTheApp )
 638     {
 639         // by default, show the assert dialog box -- we can't customize this
 640         // behaviour
 641         ShowAssertDialog(szFile, nLine, szCond, szMsg);
 642     }
 643     else
 644     {
 645         // let the app process it as it wants
 646         wxTheApp->OnAssert(szFile, nLine, szCond, szMsg);
 647     }
 648
 649     s_bInAssert = false;
 650 }
 651
 652 #endif // __WXDEBUG__
 653
 654 // ============================================================================
 655 // private functions implementation
 656 // ============================================================================
 657
 658 #ifdef __WXDEBUG__
 659
 660 static void LINKAGEMODE SetTraceMasks()
 661 {
 662 #if wxUSE_LOG
 663     wxString mask;
 664     if ( wxGetEnv(wxT("WXTRACE"), &mask) )
 665     {
 666         wxStringTokenizer tkn(mask, wxT(",;:"));
 667         while ( tkn.HasMoreTokens() )
 668             wxLog::AddTraceMask(tkn.GetNextToken());
 669     }
 670 #endif // wxUSE_LOG
 671 }
 672
 673 bool DoShowAssertDialog(const wxString& msg)
 674 {
 675     // under MSW we can show the dialog even in the console mode
 676 #if defined(__WXMSW__) && !defined(__WXMICROWIN__)
 677     wxString msgDlg(msg);
 678
 679     // this message is intentionally not translated -- it is for
 680     // developpers only
 681     msgDlg += wxT("\nDo you want to stop the program?\n")
 682               wxT("You can also choose [Cancel] to suppress ")
 683               wxT("further warnings.");
 684
 685     switch ( ::MessageBox(NULL, msgDlg, _T("wxWidgets Debug Alert"),
 686                           MB_YESNOCANCEL | MB_ICONSTOP ) )
 687     {
 688         case IDYES:
 689             wxTrap();
 690             break;
 691
 692         case IDCANCEL:
 693             // stop the asserts
 694             return true;
 695
 696         //case IDNO: nothing to do
 697     }
 698 #else // !__WXMSW__
 699     wxFprintf(stderr, wxT("%s\n"), msg.c_str());
 700     fflush(stderr);
 701
 702     // TODO: ask the user to enter "Y" or "N" on the console?
 703     wxTrap();
 704 #endif // __WXMSW__/!__WXMSW__
 705
 706     // continue with the asserts
 707     return false;
 708 }
 709
 710 // show the assert modal dialog
 711 static
 712 void ShowAssertDialog(const wxChar *szFile,
 713                       int nLine,
 714                       const wxChar *szCond,
 715                       const wxChar *szMsg,
 716                       wxAppTraits *traits)
 717 {
 718     // this variable can be set to true to suppress "assert failure" messages
 719     static bool s_bNoAsserts = false;
 720
 721     wxString msg;
 722     msg.reserve(2048);
 723
 724     // make life easier for people using VC++ IDE by using this format: like
 725     // this, clicking on the message will take us immediately to the place of
 726     // the failed assert
 727     msg.Printf(wxT("%s(%d): assert \"%s\" failed"), szFile, nLine, szCond);
 728
 729     if ( szMsg )
 730     {
 731         msg << _T(": ") << szMsg;
 732     }
 733     else // no message given
 734     {
 735         msg << _T('.');
 736     }
 737
 738 #if wxUSE_STACKWALKER
 739     class StackDump : public wxStackWalker
 740     {
 741     public:
 742         StackDump() { }
 743
 744         const wxString& GetStackTrace() const { return m_stackTrace; }
 745
 746     protected:
 747         virtual void OnStackFrame(const wxStackFrame& frame)
 748         {
 749             m_stackTrace << wxString::Format(_T("[%02d] "), frame.GetLevel());
 750
 751             wxString name = frame.GetName();
 752             if ( !name.empty() )
 753             {
 754                 m_stackTrace << wxString::Format(_T("%-40s"), name.c_str());
 755             }
 756             else
 757             {
 758                 m_stackTrace << wxString::Format
 759                                 (
 760                                     _T("0x%08lx"),
 761                                     (unsigned long)frame.GetAddress()
 762                                 );
 763             }
 764
 765             if ( frame.HasSourceLocation() )
 766             {
 767                 m_stackTrace << _T('\t')
 768                              << frame.GetFileName()
 769                              << _T(':')
 770                              << frame.GetLine();
 771             }
 772
 773             m_stackTrace << _T('\n');
 774         }
 775
 776     private:
 777         wxString m_stackTrace;
 778     };
 779
 780     StackDump dump;
 781     dump.Walk(5); // don't show OnAssert() call itself
 782     wxString stackTrace = dump.GetStackTrace();
 783
 784     // don't show more than maxLines or we could get a dialog too tall to be
 785     // shown on screen: 20 should be ok everywhere as even with 15 pixel high
 786     // characters it is still only 300 pixels...
 787     const int maxLines = 20;
 788     int count = stackTrace.Freq(wxT('\n'));
 789     if (count > maxLines)
 790     {
 791         int i;
 792         for (i = 0; i < count - maxLines; i++)
 793             stackTrace = stackTrace.BeforeLast(wxT('\n'));
 794     }
 795     if ( !stackTrace.empty() )
 796     {
 797         msg << _T("\n\nCall stack:\n")
 798             << stackTrace;
 799     }
 800 #endif // wxUSE_STACKWALKER
 801
 802 #if wxUSE_THREADS
 803     // if we are not in the main thread, output the assert directly and trap
 804     // since dialogs cannot be displayed
 805     if ( !wxThread::IsMain() )
 806     {
 807         msg += wxT(" [in child thread]");
 808
 809 #if defined(__WXMSW__) && !defined(__WXMICROWIN__)
 810         msg << wxT("\r\n");
 811         OutputDebugString(msg );
 812 #else
 813         // send to stderr
 814         wxFprintf(stderr, wxT("%s\n"), msg.c_str());
 815         fflush(stderr);
 816 #endif
 817         // He-e-e-e-elp!! we're asserting in a child thread
 818         wxTrap();
 819     }
 820     else
 821 #endif // wxUSE_THREADS
 822
 823     if ( !s_bNoAsserts )
 824     {
 825         // send it to the normal log destination
 826         wxLogDebug(_T("%s"), msg.c_str());
 827
 828         if ( traits )
 829         {
 830             // delegate showing assert dialog (if possible) to that class
 831             s_bNoAsserts = traits->ShowAssertDialog(msg);
 832         }
 833         else // no traits object
 834         {
 835             // fall back to the function of last resort
 836             s_bNoAsserts = DoShowAssertDialog(msg);
 837         }
 838     }
 839 }
 840
 841 #endif // __WXDEBUG__
 842