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 ( !wxPendingEventsLocker )
 273         return;
 274
 275     // ensure that we're the only thread to modify the pending events list
 276     wxENTER_CRIT_SECT( *wxPendingEventsLocker );
 277
 278     if ( !wxPendingEvents )
 279     {
 280         wxLEAVE_CRIT_SECT( *wxPendingEventsLocker );
 281         return;
 282     }
 283
 284     // iterate until the list becomes empty
 285     wxList::compatibility_iterator node = wxPendingEvents->GetFirst();
 286     while (node)
 287     {
 288         wxEvtHandler *handler = (wxEvtHandler *)node->GetData();
 289         wxPendingEvents->Erase(node);
 290
 291         // In ProcessPendingEvents(), new handlers might be add
 292         // and we can safely leave the critical section here.
 293         wxLEAVE_CRIT_SECT( *wxPendingEventsLocker );
 294         handler->ProcessPendingEvents();
 295         wxENTER_CRIT_SECT( *wxPendingEventsLocker );
 296
 297         node = wxPendingEvents->GetFirst();
 298     }
 299
 300     wxLEAVE_CRIT_SECT( *wxPendingEventsLocker );
 301 }
 302
 303 int wxAppConsole::FilterEvent(wxEvent& WXUNUSED(event))
 304 {
 305     // process the events normally by default
 306     return -1;
 307 }
 308
 309 // ----------------------------------------------------------------------------
 310 // exception handling
 311 // ----------------------------------------------------------------------------
 312
 313 #if wxUSE_EXCEPTIONS
 314
 315 void
 316 wxAppConsole::HandleEvent(wxEvtHandler *handler,
 317                           wxEventFunction func,
 318                           wxEvent& event) const
 319 {
 320     // by default, simply call the handler
 321     (handler->*func)(event);
 322 }
 323
 324 bool
 325 wxAppConsole::OnExceptionInMainLoop()
 326 {
 327     throw;
 328
 329     // some compilers are too stupid to know that we never return after throw
 330 #if defined(__DMC__) || (defined(_MSC_VER) && _MSC_VER < 1200)
 331     return false;
 332 #endif
 333 }
 334
 335 #endif // wxUSE_EXCEPTIONS
 336
 337 // ----------------------------------------------------------------------------
 338 // cmd line parsing
 339 // ----------------------------------------------------------------------------
 340
 341 #if wxUSE_CMDLINE_PARSER
 342
 343 #define OPTION_VERBOSE _T("verbose")
 344
 345 void wxAppConsole::OnInitCmdLine(wxCmdLineParser& parser)
 346 {
 347     // the standard command line options
 348     static const wxCmdLineEntryDesc cmdLineDesc[] =
 349     {
 350         {
 351             wxCMD_LINE_SWITCH,
 352             _T("h"),
 353             _T("help"),
 354             gettext_noop("show this help message"),
 355             wxCMD_LINE_VAL_NONE,
 356             wxCMD_LINE_OPTION_HELP
 357         },
 358
 359 #if wxUSE_LOG
 360         {
 361             wxCMD_LINE_SWITCH,
 362             wxEmptyString,
 363             OPTION_VERBOSE,
 364             gettext_noop("generate verbose log messages"),
 365             wxCMD_LINE_VAL_NONE,
 366             0x0
 367         },
 368 #endif // wxUSE_LOG
 369
 370         // terminator
 371         {
 372             wxCMD_LINE_NONE,
 373             wxEmptyString,
 374             wxEmptyString,
 375             wxEmptyString,
 376             wxCMD_LINE_VAL_NONE,
 377             0x0
 378         }
 379     };
 380
 381     parser.SetDesc(cmdLineDesc);
 382 }
 383
 384 bool wxAppConsole::OnCmdLineParsed(wxCmdLineParser& parser)
 385 {
 386 #if wxUSE_LOG
 387     if ( parser.Found(OPTION_VERBOSE) )
 388     {
 389         wxLog::SetVerbose(true);
 390     }
 391 #else
 392     wxUnusedVar(parser);
 393 #endif // wxUSE_LOG
 394
 395     return true;
 396 }
 397
 398 bool wxAppConsole::OnCmdLineHelp(wxCmdLineParser& parser)
 399 {
 400     parser.Usage();
 401
 402     return false;
 403 }
 404
 405 bool wxAppConsole::OnCmdLineError(wxCmdLineParser& parser)
 406 {
 407     parser.Usage();
 408
 409     return false;
 410 }
 411
 412 #endif // wxUSE_CMDLINE_PARSER
 413
 414 // ----------------------------------------------------------------------------
 415 // debugging support
 416 // ----------------------------------------------------------------------------
 417
 418 /* static */
 419 bool wxAppConsole::CheckBuildOptions(const char *optionsSignature,
 420                                      const char *componentName)
 421 {
 422 #if 0 // can't use wxLogTrace, not up and running yet
 423     printf("checking build options object '%s' (ptr %p) in '%s'\n",
 424              optionsSignature, optionsSignature, componentName);
 425 #endif
 426
 427     if ( strcmp(optionsSignature, WX_BUILD_OPTIONS_SIGNATURE) != 0 )
 428     {
 429         wxString lib = wxString::FromAscii(WX_BUILD_OPTIONS_SIGNATURE);
 430         wxString prog = wxString::FromAscii(optionsSignature);
 431         wxString progName = wxString::FromAscii(componentName);
 432         wxString msg;
 433
 434         msg.Printf(_T("Mismatch between the program and library build versions detected.\nThe library used %s,\nand %s used %s."),
 435                    lib.c_str(), progName.c_str(), prog.c_str());
 436
 437         wxLogFatalError(msg.c_str());
 438
 439         // normally wxLogFatalError doesn't return
 440         return false;
 441     }
 442 #undef wxCMP
 443
 444     return true;
 445 }
 446
 447 #ifdef __WXDEBUG__
 448
 449 void wxAppConsole::OnAssert(const wxChar *file,
 450                             int line,
 451                             const wxChar *cond,
 452                             const wxChar *msg)
 453 {
 454     ShowAssertDialog(file, line, cond, msg, GetTraits());
 455 }
 456
 457 #endif // __WXDEBUG__
 458
 459 #if WXWIN_COMPATIBILITY_2_4
 460
 461 bool wxAppConsole::CheckBuildOptions(const wxBuildOptions& buildOptions)
 462 {
 463     return CheckBuildOptions(buildOptions.m_signature, "your program");
 464 }
 465
 466 #endif
 467
 468 // ============================================================================
 469 // other classes implementations
 470 // ============================================================================
 471
 472 // ----------------------------------------------------------------------------
 473 // wxConsoleAppTraitsBase
 474 // ----------------------------------------------------------------------------
 475
 476 #if wxUSE_LOG
 477
 478 wxLog *wxConsoleAppTraitsBase::CreateLogTarget()
 479 {
 480     return new wxLogStderr;
 481 }
 482
 483 #endif // wxUSE_LOG
 484
 485 wxMessageOutput *wxConsoleAppTraitsBase::CreateMessageOutput()
 486 {
 487     return new wxMessageOutputStderr;
 488 }
 489
 490 #if wxUSE_FONTMAP
 491
 492 wxFontMapper *wxConsoleAppTraitsBase::CreateFontMapper()
 493 {
 494     return (wxFontMapper *)new wxFontMapperBase;
 495 }
 496
 497 #endif // wxUSE_FONTMAP
 498
 499 wxRendererNative *wxConsoleAppTraitsBase::CreateRenderer()
 500 {
 501     // console applications don't use renderers
 502     return NULL;
 503 }
 504
 505 #ifdef __WXDEBUG__
 506 bool wxConsoleAppTraitsBase::ShowAssertDialog(const wxString& msg)
 507 {
 508     return wxAppTraitsBase::ShowAssertDialog(msg);
 509 }
 510 #endif
 511
 512 bool wxConsoleAppTraitsBase::HasStderr()
 513 {
 514     // console applications always have stderr, even under Mac/Windows
 515     return true;
 516 }
 517
 518 void wxConsoleAppTraitsBase::ScheduleForDestroy(wxObject *object)
 519 {
 520     delete object;
 521 }
 522
 523 void wxConsoleAppTraitsBase::RemoveFromPendingDelete(wxObject * WXUNUSED(object))
 524 {
 525     // nothing to do
 526 }
 527
 528 #if wxUSE_SOCKETS
 529 GSocketGUIFunctionsTable* wxConsoleAppTraitsBase::GetSocketGUIFunctionsTable()
 530 {
 531     return NULL;
 532 }
 533 #endif
 534
 535 // ----------------------------------------------------------------------------
 536 // wxAppTraits
 537 // ----------------------------------------------------------------------------
 538
 539 #ifdef __WXDEBUG__
 540
 541 bool wxAppTraitsBase::ShowAssertDialog(const wxString& msg)
 542 {
 543     return DoShowAssertDialog(msg);
 544 }
 545
 546 #endif // __WXDEBUG__
 547
 548 // ============================================================================
 549 // global functions implementation
 550 // ============================================================================
 551
 552 void wxExit()
 553 {
 554     if ( wxTheApp )
 555     {
 556         wxTheApp->Exit();
 557     }
 558     else
 559     {
 560         // what else can we do?
 561         exit(-1);
 562     }
 563 }
 564
 565 void wxWakeUpIdle()
 566 {
 567     if ( wxTheApp )
 568     {
 569         wxTheApp->WakeUpIdle();
 570     }
 571     //else: do nothing, what can we do?
 572 }
 573
 574 #ifdef  __WXDEBUG__
 575
 576 // wxASSERT() helper
 577 bool wxAssertIsEqual(int x, int y)
 578 {
 579     return x == y;
 580 }
 581
 582 // break into the debugger
 583 void wxTrap()
 584 {
 585 #if defined(__WXMSW__) && !defined(__WXMICROWIN__)
 586     DebugBreak();
 587 #elif defined(__WXMAC__) && !defined(__DARWIN__)
 588     #if __powerc
 589         Debugger();
 590     #else
 591         SysBreak();
 592     #endif
 593 #elif defined(_MSL_USING_MW_C_HEADERS) && _MSL_USING_MW_C_HEADERS
 594     Debugger();
 595 #elif defined(__UNIX__)
 596     raise(SIGTRAP);
 597 #else
 598     // TODO
 599 #endif // Win/Unix
 600 }
 601
 602 void wxAssert(int cond,
 603               const wxChar *szFile,
 604               int nLine,
 605               const wxChar *szCond,
 606               const wxChar *szMsg)
 607 {
 608     if ( !cond )
 609         wxOnAssert(szFile, nLine, szCond, szMsg);
 610 }
 611
 612 // this function is called when an assert fails
 613 void wxOnAssert(const wxChar *szFile,
 614                 int nLine,
 615                 const wxChar *szCond,
 616                 const wxChar *szMsg)
 617 {
 618     // FIXME MT-unsafe
 619     static bool s_bInAssert = false;
 620
 621     if ( s_bInAssert )
 622     {
 623         // He-e-e-e-elp!! we're trapped in endless loop
 624         wxTrap();
 625
 626         s_bInAssert = false;
 627
 628         return;
 629     }
 630
 631     s_bInAssert = true;
 632
 633     if ( !wxTheApp )
 634     {
 635         // by default, show the assert dialog box -- we can't customize this
 636         // behaviour
 637         ShowAssertDialog(szFile, nLine, szCond, szMsg);
 638     }
 639     else
 640     {
 641         // let the app process it as it wants
 642         wxTheApp->OnAssert(szFile, nLine, szCond, szMsg);
 643     }
 644
 645     s_bInAssert = false;
 646 }
 647
 648 #endif // __WXDEBUG__
 649
 650 // ============================================================================
 651 // private functions implementation
 652 // ============================================================================
 653
 654 #ifdef __WXDEBUG__
 655
 656 static void LINKAGEMODE SetTraceMasks()
 657 {
 658 #if wxUSE_LOG
 659     wxString mask;
 660     if ( wxGetEnv(wxT("WXTRACE"), &mask) )
 661     {
 662         wxStringTokenizer tkn(mask, wxT(",;:"));
 663         while ( tkn.HasMoreTokens() )
 664             wxLog::AddTraceMask(tkn.GetNextToken());
 665     }
 666 #endif // wxUSE_LOG
 667 }
 668
 669 bool DoShowAssertDialog(const wxString& msg)
 670 {
 671     // under MSW we can show the dialog even in the console mode
 672 #if defined(__WXMSW__) && !defined(__WXMICROWIN__)
 673     wxString msgDlg(msg);
 674
 675     // this message is intentionally not translated -- it is for
 676     // developpers only
 677     msgDlg += wxT("\nDo you want to stop the program?\n")
 678               wxT("You can also choose [Cancel] to suppress ")
 679               wxT("further warnings.");
 680
 681     switch ( ::MessageBox(NULL, msgDlg, _T("wxWidgets Debug Alert"),
 682                           MB_YESNOCANCEL | MB_ICONSTOP ) )
 683     {
 684         case IDYES:
 685             wxTrap();
 686             break;
 687
 688         case IDCANCEL:
 689             // stop the asserts
 690             return true;
 691
 692         //case IDNO: nothing to do
 693     }
 694 #else // !__WXMSW__
 695     wxFprintf(stderr, wxT("%s\n"), msg.c_str());
 696     fflush(stderr);
 697
 698     // TODO: ask the user to enter "Y" or "N" on the console?
 699     wxTrap();
 700 #endif // __WXMSW__/!__WXMSW__
 701
 702     // continue with the asserts
 703     return false;
 704 }
 705
 706 // show the assert modal dialog
 707 static
 708 void ShowAssertDialog(const wxChar *szFile,
 709                       int nLine,
 710                       const wxChar *szCond,
 711                       const wxChar *szMsg,
 712                       wxAppTraits *traits)
 713 {
 714     // this variable can be set to true to suppress "assert failure" messages
 715     static bool s_bNoAsserts = false;
 716
 717     wxString msg;
 718     msg.reserve(2048);
 719
 720     // make life easier for people using VC++ IDE by using this format: like
 721     // this, clicking on the message will take us immediately to the place of
 722     // the failed assert
 723     msg.Printf(wxT("%s(%d): assert \"%s\" failed"), szFile, nLine, szCond);
 724
 725     if ( szMsg )
 726     {
 727         msg << _T(": ") << szMsg;
 728     }
 729     else // no message given
 730     {
 731         msg << _T('.');
 732     }
 733
 734 #if wxUSE_STACKWALKER
 735     class StackDump : public wxStackWalker
 736     {
 737     public:
 738         StackDump() { }
 739
 740         const wxString& GetStackTrace() const { return m_stackTrace; }
 741
 742     protected:
 743         virtual void OnStackFrame(const wxStackFrame& frame)
 744         {
 745             m_stackTrace << wxString::Format(_T("[%02d] "), frame.GetLevel());
 746
 747             wxString name = frame.GetName();
 748             if ( !name.empty() )
 749             {
 750                 m_stackTrace << wxString::Format(_T("%-40s"), name.c_str());
 751             }
 752             else
 753             {
 754                 m_stackTrace << wxString::Format
 755                                 (
 756                                     _T("0x%08lx"),
 757                                     (unsigned long)frame.GetAddress()
 758                                 );
 759             }
 760
 761             if ( frame.HasSourceLocation() )
 762             {
 763                 m_stackTrace << _T('\t')
 764                              << frame.GetFileName()
 765                              << _T(':')
 766                              << frame.GetLine();
 767             }
 768
 769             m_stackTrace << _T('\n');
 770         }
 771
 772     private:
 773         wxString m_stackTrace;
 774     };
 775
 776     StackDump dump;
 777     dump.Walk(5); // don't show OnAssert() call itself
 778     wxString stackTrace = dump.GetStackTrace();
 779
 780     // don't show more than maxLines or we could get a dialog too tall to be
 781     // shown on screen: 20 should be ok everywhere as even with 15 pixel high
 782     // characters it is still only 300 pixels...
 783     const int maxLines = 20;
 784     int count = stackTrace.Freq(wxT('\n'));
 785     if (count > maxLines)
 786     {
 787         int i;
 788         for (i = 0; i < count - maxLines; i++)
 789             stackTrace = stackTrace.BeforeLast(wxT('\n'));
 790     }
 791     if ( !stackTrace.empty() )
 792     {
 793         msg << _T("\n\nCall stack:\n")
 794             << stackTrace;
 795     }
 796 #endif // wxUSE_STACKWALKER
 797
 798 #if wxUSE_THREADS
 799     // if we are not in the main thread, output the assert directly and trap
 800     // since dialogs cannot be displayed
 801     if ( !wxThread::IsMain() )
 802     {
 803         msg += wxT(" [in child thread]");
 804
 805 #if defined(__WXMSW__) && !defined(__WXMICROWIN__)
 806         msg << wxT("\r\n");
 807         OutputDebugString(msg );
 808 #else
 809         // send to stderr
 810         wxFprintf(stderr, wxT("%s\n"), msg.c_str());
 811         fflush(stderr);
 812 #endif
 813         // He-e-e-e-elp!! we're asserting in a child thread
 814         wxTrap();
 815     }
 816     else
 817 #endif // wxUSE_THREADS
 818
 819     if ( !s_bNoAsserts )
 820     {
 821         // send it to the normal log destination
 822         wxLogDebug(_T("%s"), msg.c_str());
 823
 824         if ( traits )
 825         {
 826             // delegate showing assert dialog (if possible) to that class
 827             s_bNoAsserts = traits->ShowAssertDialog(msg);
 828         }
 829         else // no traits object
 830         {
 831             // fall back to the function of last resort
 832             s_bNoAsserts = DoShowAssertDialog(msg);
 833         }
 834     }
 835 }
 836
 837 #endif // __WXDEBUG__
 838