src/msw/app.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/app.cpp
   3 // Purpose:     wxApp
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     04/01/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  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 #if defined(__BORLANDC__)
  24     #pragma hdrstop
  25 #endif
  26
  27 #ifndef WX_PRECOMP
  28     #include "wx/msw/wrapcctl.h"
  29     #include "wx/dynarray.h"
  30     #include "wx/frame.h"
  31     #include "wx/app.h"
  32     #include "wx/utils.h"
  33     #include "wx/gdicmn.h"
  34     #include "wx/pen.h"
  35     #include "wx/brush.h"
  36     #include "wx/cursor.h"
  37     #include "wx/icon.h"
  38     #include "wx/palette.h"
  39     #include "wx/dc.h"
  40     #include "wx/dialog.h"
  41     #include "wx/msgdlg.h"
  42     #include "wx/intl.h"
  43     #include "wx/crt.h"
  44     #include "wx/log.h"
  45     #include "wx/module.h"
  46 #endif
  47
  48 #include "wx/apptrait.h"
  49 #include "wx/filename.h"
  50 #include "wx/dynlib.h"
  51 #include "wx/evtloop.h"
  52
  53 #include "wx/msw/private.h"
  54 #include "wx/msw/ole/oleutils.h"
  55 #include "wx/msw/private/timer.h"
  56
  57 #if wxUSE_TOOLTIPS
  58     #include "wx/tooltip.h"
  59 #endif // wxUSE_TOOLTIPS
  60
  61 // OLE is used for drag-and-drop, clipboard, OLE Automation..., but some
  62 // compilers don't support it (missing headers, libs, ...)
  63 #if defined(__GNUWIN32_OLD__) || defined(__SYMANTEC__) || defined(__SALFORDC__)
  64     #undef wxUSE_OLE
  65
  66     #define  wxUSE_OLE 0
  67 #endif // broken compilers
  68
  69 #if defined(__POCKETPC__) || defined(__SMARTPHONE__)
  70     #include <ole2.h>
  71     #include <aygshell.h>
  72 #endif
  73
  74 #if wxUSE_OLE
  75     #include <ole2.h>
  76 #endif
  77
  78 #include <string.h>
  79 #include <ctype.h>
  80
  81 #include "wx/msw/missing.h"
  82
  83 // instead of including <shlwapi.h> which is not part of the core SDK and not
  84 // shipped at all with other compilers, we always define the parts of it we
  85 // need here ourselves
  86 //
  87 // NB: DLLVER_PLATFORM_WINDOWS will be defined if shlwapi.h had been somehow
  88 //     included already
  89 #ifndef DLLVER_PLATFORM_WINDOWS
  90     // hopefully we don't need to change packing as DWORDs should be already
  91     // correctly aligned
  92     struct DLLVERSIONINFO
  93     {
  94         DWORD cbSize;
  95         DWORD dwMajorVersion;                   // Major version
  96         DWORD dwMinorVersion;                   // Minor version
  97         DWORD dwBuildNumber;                    // Build number
  98         DWORD dwPlatformID;                     // DLLVER_PLATFORM_*
  99     };
 100
 101     typedef HRESULT (CALLBACK* DLLGETVERSIONPROC)(DLLVERSIONINFO *);
 102 #endif // defined(DLLVERSIONINFO)
 103
 104
 105 // ---------------------------------------------------------------------------
 106 // global variables
 107 // ---------------------------------------------------------------------------
 108
 109 #if !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
 110 extern void wxSetKeyboardHook(bool doIt);
 111 #endif
 112
 113 // NB: all "NoRedraw" classes must have the same names as the "normal" classes
 114 //     with NR suffix - wxWindow::MSWCreate() supposes this
 115 #ifdef __WXWINCE__
 116 WXDLLIMPEXP_CORE       wxChar *wxCanvasClassName;
 117 WXDLLIMPEXP_CORE       wxChar *wxCanvasClassNameNR;
 118 #else
 119 WXDLLIMPEXP_CORE const wxChar *wxCanvasClassName        = wxT("wxWindowClass");
 120 WXDLLIMPEXP_CORE const wxChar *wxCanvasClassNameNR      = wxT("wxWindowClassNR");
 121 #endif
 122 WXDLLIMPEXP_CORE const wxChar *wxMDIFrameClassName      = wxT("wxMDIFrameClass");
 123 WXDLLIMPEXP_CORE const wxChar *wxMDIFrameClassNameNoRedraw = wxT("wxMDIFrameClassNR");
 124 WXDLLIMPEXP_CORE const wxChar *wxMDIChildFrameClassName = wxT("wxMDIChildFrameClass");
 125 WXDLLIMPEXP_CORE const wxChar *wxMDIChildFrameClassNameNoRedraw = wxT("wxMDIChildFrameClassNR");
 126
 127 // ----------------------------------------------------------------------------
 128 // private functions
 129 // ----------------------------------------------------------------------------
 130
 131 LRESULT WXDLLEXPORT APIENTRY wxWndProc(HWND, UINT, WPARAM, LPARAM);
 132
 133 // ===========================================================================
 134 // wxGUIAppTraits implementation
 135 // ===========================================================================
 136
 137 // private class which we use to pass parameters from BeforeChildWaitLoop() to
 138 // AfterChildWaitLoop()
 139 struct ChildWaitLoopData
 140 {
 141     ChildWaitLoopData(wxWindowDisabler *wd_, wxWindow *winActive_)
 142     {
 143         wd = wd_;
 144         winActive = winActive_;
 145     }
 146
 147     wxWindowDisabler *wd;
 148     wxWindow *winActive;
 149 };
 150
 151 void *wxGUIAppTraits::BeforeChildWaitLoop()
 152 {
 153     /*
 154        We use a dirty hack here to disable all application windows (which we
 155        must do because otherwise the calls to wxYield() could lead to some very
 156        unexpected reentrancies in the users code) but to avoid losing
 157        focus/activation entirely when the child process terminates which would
 158        happen if we simply disabled everything using wxWindowDisabler. Indeed,
 159        remember that Windows will never activate a disabled window and when the
 160        last childs window is closed and Windows looks for a window to activate
 161        all our windows are still disabled. There is no way to enable them in
 162        time because we don't know when the childs windows are going to be
 163        closed, so the solution we use here is to keep one special tiny frame
 164        enabled all the time. Then when the child terminates it will get
 165        activated and when we close it below -- after reenabling all the other
 166        windows! -- the previously active window becomes activated again and
 167        everything is ok.
 168      */
 169     wxBeginBusyCursor();
 170
 171     // first disable all existing windows
 172     wxWindowDisabler *wd = new wxWindowDisabler;
 173
 174     // then create an "invisible" frame: it has minimal size, is positioned
 175     // (hopefully) outside the screen and doesn't appear on the taskbar
 176     wxWindow *winActive = new wxFrame
 177                     (
 178                         wxTheApp->GetTopWindow(),
 179                         wxID_ANY,
 180                         wxEmptyString,
 181                         wxPoint(32600, 32600),
 182                         wxSize(1, 1),
 183                         wxDEFAULT_FRAME_STYLE | wxFRAME_NO_TASKBAR
 184                     );
 185     winActive->Show();
 186
 187     return new ChildWaitLoopData(wd, winActive);
 188 }
 189
 190 void wxGUIAppTraits::AlwaysYield()
 191 {
 192     wxYield();
 193 }
 194
 195 void wxGUIAppTraits::AfterChildWaitLoop(void *dataOrig)
 196 {
 197     wxEndBusyCursor();
 198
 199     ChildWaitLoopData * const data = (ChildWaitLoopData *)dataOrig;
 200
 201     delete data->wd;
 202
 203     // finally delete the dummy frame and, as wd has been already destroyed and
 204     // the other windows reenabled, the activation is going to return to the
 205     // window which had had it before
 206     data->winActive->Destroy();
 207
 208     // also delete the temporary data object itself
 209     delete data;
 210 }
 211
 212 bool wxGUIAppTraits::DoMessageFromThreadWait()
 213 {
 214     // we should return false only if the app should exit, i.e. only if
 215     // Dispatch() determines that the main event loop should terminate
 216     wxEventLoopBase * const evtLoop = wxEventLoop::GetActive();
 217     if ( !evtLoop || !evtLoop->Pending() )
 218     {
 219         // no events means no quit event
 220         return true;
 221     }
 222
 223     return evtLoop->Dispatch();
 224 }
 225
 226 DWORD wxGUIAppTraits::WaitForThread(WXHANDLE hThread)
 227 {
 228     // if we don't have a running event loop, we shouldn't wait for the
 229     // messages as we never remove them from the message queue and so we enter
 230     // an infinite loop as MsgWaitForMultipleObjects() keeps returning
 231     // WAIT_OBJECT_0 + 1
 232     if ( !wxEventLoop::GetActive() )
 233         return DoSimpleWaitForThread(hThread);
 234
 235     return ::MsgWaitForMultipleObjects
 236              (
 237                1,                   // number of objects to wait for
 238                (HANDLE *)&hThread,  // the objects
 239                false,               // wait for any objects, not all
 240                INFINITE,            // no timeout
 241                QS_ALLINPUT |        // return as soon as there are any events
 242                QS_ALLPOSTMESSAGE
 243              );
 244 }
 245
 246 wxPortId wxGUIAppTraits::GetToolkitVersion(int *majVer, int *minVer) const
 247 {
 248     OSVERSIONINFO info;
 249     wxZeroMemory(info);
 250
 251     // on Windows, the toolkit version is the same of the OS version
 252     // as Windows integrates the OS kernel with the GUI toolkit.
 253     info.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
 254     if ( ::GetVersionEx(&info) )
 255     {
 256         if ( majVer )
 257             *majVer = info.dwMajorVersion;
 258         if ( minVer )
 259             *minVer = info.dwMinorVersion;
 260     }
 261
 262 #if defined(__WXHANDHELD__) || defined(__WXWINCE__)
 263     return wxPORT_WINCE;
 264 #else
 265     return wxPORT_MSW;
 266 #endif
 267 }
 268
 269 #if wxUSE_TIMER
 270
 271 wxTimerImpl *wxGUIAppTraits::CreateTimerImpl(wxTimer *timer)
 272 {
 273     return new wxMSWTimerImpl(timer);
 274 }
 275
 276 #endif // wxUSE_TIMER
 277
 278 wxEventLoopBase* wxGUIAppTraits::CreateEventLoop()
 279 {
 280     return new wxEventLoop;
 281 }
 282
 283 // ===========================================================================
 284 // wxApp implementation
 285 // ===========================================================================
 286
 287 int wxApp::m_nCmdShow = SW_SHOWNORMAL;
 288
 289 // ---------------------------------------------------------------------------
 290 // wxWin macros
 291 // ---------------------------------------------------------------------------
 292
 293 IMPLEMENT_DYNAMIC_CLASS(wxApp, wxEvtHandler)
 294
 295 BEGIN_EVENT_TABLE(wxApp, wxEvtHandler)
 296     EVT_IDLE(wxApp::OnIdle)
 297     EVT_END_SESSION(wxApp::OnEndSession)
 298     EVT_QUERY_END_SESSION(wxApp::OnQueryEndSession)
 299 END_EVENT_TABLE()
 300
 301 // class to ensure that wxAppBase::CleanUp() is called if our Initialize()
 302 // fails
 303 class wxCallBaseCleanup
 304 {
 305 public:
 306     wxCallBaseCleanup(wxApp *app) : m_app(app) { }
 307     ~wxCallBaseCleanup() { if ( m_app ) m_app->wxAppBase::CleanUp(); }
 308
 309     void Dismiss() { m_app = NULL; }
 310
 311 private:
 312     wxApp *m_app;
 313 };
 314
 315 //// Initialize
 316 bool wxApp::Initialize(int& argc, wxChar **argv)
 317 {
 318     if ( !wxAppBase::Initialize(argc, argv) )
 319         return false;
 320
 321     // ensure that base cleanup is done if we return too early
 322     wxCallBaseCleanup callBaseCleanup(this);
 323
 324 #ifdef __WXWINCE__
 325     wxString tmp = GetAppName();
 326     tmp += wxT("ClassName");
 327     wxCanvasClassName = wxStrdup( tmp.wc_str() );
 328     tmp += wxT("NR");
 329     wxCanvasClassNameNR = wxStrdup( tmp.wc_str() );
 330     HWND hWnd = FindWindow( wxCanvasClassNameNR, NULL );
 331     if (hWnd)
 332     {
 333         SetForegroundWindow( (HWND)(((DWORD)hWnd)|0x01) );
 334         return false;
 335     }
 336 #endif
 337
 338 #if !defined(__WXMICROWIN__)
 339     InitCommonControls();
 340 #endif // !defined(__WXMICROWIN__)
 341
 342 #if defined(__SMARTPHONE__) || defined(__POCKETPC__)
 343     SHInitExtraControls();
 344 #endif
 345
 346 #ifndef __WXWINCE__
 347     // Don't show a message box if a function such as SHGetFileInfo
 348     // fails to find a device.
 349     SetErrorMode(SEM_FAILCRITICALERRORS|SEM_NOOPENFILEERRORBOX);
 350 #endif
 351
 352     wxOleInitialize();
 353
 354     RegisterWindowClasses();
 355
 356     wxWinHandleHash = new wxWinHashTable(wxKEY_INTEGER, 100);
 357
 358 #if !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
 359     wxSetKeyboardHook(true);
 360 #endif
 361
 362     callBaseCleanup.Dismiss();
 363
 364     return true;
 365 }
 366
 367 // ---------------------------------------------------------------------------
 368 // RegisterWindowClasses
 369 // ---------------------------------------------------------------------------
 370
 371 // TODO we should only register classes really used by the app. For this it
 372 //      would be enough to just delay the class registration until an attempt
 373 //      to create a window of this class is made.
 374 bool wxApp::RegisterWindowClasses()
 375 {
 376     WNDCLASS wndclass;
 377     wxZeroMemory(wndclass);
 378
 379     // for each class we register one with CS_(V|H)REDRAW style and one
 380     // without for windows created with wxNO_FULL_REDRAW_ON_REPAINT flag
 381     static const long styleNormal = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS;
 382     static const long styleNoRedraw = CS_DBLCLKS;
 383
 384     // the fields which are common to all classes
 385     wndclass.lpfnWndProc   = (WNDPROC)wxWndProc;
 386     wndclass.hInstance     = wxhInstance;
 387     wndclass.hCursor       = ::LoadCursor((HINSTANCE)NULL, IDC_ARROW);
 388
 389     // register the class for all normal windows
 390     wndclass.hbrBackground = (HBRUSH)(COLOR_BTNFACE + 1);
 391     wndclass.lpszClassName = wxCanvasClassName;
 392     wndclass.style         = styleNormal;
 393
 394     if ( !RegisterClass(&wndclass) )
 395     {
 396         wxLogLastError(wxT("RegisterClass(frame)"));
 397     }
 398
 399     // "no redraw" frame
 400     wndclass.lpszClassName = wxCanvasClassNameNR;
 401     wndclass.style         = styleNoRedraw;
 402
 403     if ( !RegisterClass(&wndclass) )
 404     {
 405         wxLogLastError(wxT("RegisterClass(no redraw frame)"));
 406     }
 407
 408     // Register the MDI frame window class.
 409     wndclass.hbrBackground = (HBRUSH)NULL; // paint MDI frame ourselves
 410     wndclass.lpszClassName = wxMDIFrameClassName;
 411     wndclass.style         = styleNormal;
 412
 413     if ( !RegisterClass(&wndclass) )
 414     {
 415         wxLogLastError(wxT("RegisterClass(MDI parent)"));
 416     }
 417
 418     // "no redraw" MDI frame
 419     wndclass.lpszClassName = wxMDIFrameClassNameNoRedraw;
 420     wndclass.style         = styleNoRedraw;
 421
 422     if ( !RegisterClass(&wndclass) )
 423     {
 424         wxLogLastError(wxT("RegisterClass(no redraw MDI parent frame)"));
 425     }
 426
 427     // Register the MDI child frame window class.
 428     wndclass.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
 429     wndclass.lpszClassName = wxMDIChildFrameClassName;
 430     wndclass.style         = styleNormal;
 431
 432     if ( !RegisterClass(&wndclass) )
 433     {
 434         wxLogLastError(wxT("RegisterClass(MDI child)"));
 435     }
 436
 437     // "no redraw" MDI child frame
 438     wndclass.lpszClassName = wxMDIChildFrameClassNameNoRedraw;
 439     wndclass.style         = styleNoRedraw;
 440
 441     if ( !RegisterClass(&wndclass) )
 442     {
 443         wxLogLastError(wxT("RegisterClass(no redraw MDI child)"));
 444     }
 445
 446     return true;
 447 }
 448
 449 // ---------------------------------------------------------------------------
 450 // UnregisterWindowClasses
 451 // ---------------------------------------------------------------------------
 452
 453 bool wxApp::UnregisterWindowClasses()
 454 {
 455     bool retval = true;
 456
 457 #ifndef __WXMICROWIN__
 458     // MDI frame window class.
 459     if ( !::UnregisterClass(wxMDIFrameClassName, wxhInstance) )
 460     {
 461         wxLogLastError(wxT("UnregisterClass(MDI parent)"));
 462
 463         retval = false;
 464     }
 465
 466     // "no redraw" MDI frame
 467     if ( !::UnregisterClass(wxMDIFrameClassNameNoRedraw, wxhInstance) )
 468     {
 469         wxLogLastError(wxT("UnregisterClass(no redraw MDI parent frame)"));
 470
 471         retval = false;
 472     }
 473
 474     // MDI child frame window class.
 475     if ( !::UnregisterClass(wxMDIChildFrameClassName, wxhInstance) )
 476     {
 477         wxLogLastError(wxT("UnregisterClass(MDI child)"));
 478
 479         retval = false;
 480     }
 481
 482     // "no redraw" MDI child frame
 483     if ( !::UnregisterClass(wxMDIChildFrameClassNameNoRedraw, wxhInstance) )
 484     {
 485         wxLogLastError(wxT("UnregisterClass(no redraw MDI child)"));
 486
 487         retval = false;
 488     }
 489
 490     // canvas class name
 491     if ( !::UnregisterClass(wxCanvasClassName, wxhInstance) )
 492     {
 493         wxLogLastError(wxT("UnregisterClass(canvas)"));
 494
 495         retval = false;
 496     }
 497
 498     if ( !::UnregisterClass(wxCanvasClassNameNR, wxhInstance) )
 499     {
 500         wxLogLastError(wxT("UnregisterClass(no redraw canvas)"));
 501
 502         retval = false;
 503     }
 504 #endif // __WXMICROWIN__
 505
 506     return retval;
 507 }
 508
 509 void wxApp::CleanUp()
 510 {
 511     // all objects pending for deletion must be deleted first, otherwise we
 512     // would crash when they use wxWinHandleHash (and UnregisterWindowClasses()
 513     // call wouldn't succeed as long as any windows still exist), so call the
 514     // base class method first and only then do our clean up
 515     wxAppBase::CleanUp();
 516
 517 #if !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
 518     wxSetKeyboardHook(false);
 519 #endif
 520
 521     wxOleUninitialize();
 522
 523     // for an EXE the classes are unregistered when it terminates but DLL may
 524     // be loaded several times (load/unload/load) into the same process in
 525     // which case the registration will fail after the first time if we don't
 526     // unregister the classes now
 527     UnregisterWindowClasses();
 528
 529     delete wxWinHandleHash;
 530     wxWinHandleHash = NULL;
 531
 532 #ifdef __WXWINCE__
 533     free( wxCanvasClassName );
 534     free( wxCanvasClassNameNR );
 535 #endif
 536 }
 537
 538 // ----------------------------------------------------------------------------
 539 // wxApp ctor/dtor
 540 // ----------------------------------------------------------------------------
 541
 542 wxApp::wxApp()
 543 {
 544     m_printMode = wxPRINT_WINDOWS;
 545 }
 546
 547 wxApp::~wxApp()
 548 {
 549 }
 550
 551 // ----------------------------------------------------------------------------
 552 // wxApp idle handling
 553 // ----------------------------------------------------------------------------
 554
 555 void wxApp::OnIdle(wxIdleEvent& WXUNUSED(event))
 556 {
 557 #if wxUSE_DC_CACHEING
 558     // automated DC cache management: clear the cached DCs and bitmap
 559     // if it's likely that the app has finished with them, that is, we
 560     // get an idle event and we're not dragging anything.
 561     if (!::GetKeyState(MK_LBUTTON) && !::GetKeyState(MK_MBUTTON) && !::GetKeyState(MK_RBUTTON))
 562         wxMSWDCImpl::ClearCache();
 563 #endif // wxUSE_DC_CACHEING
 564 }
 565
 566 void wxApp::WakeUpIdle()
 567 {
 568     // Send the top window a dummy message so idle handler processing will
 569     // start up again.  Doing it this way ensures that the idle handler
 570     // wakes up in the right thread (see also wxWakeUpMainThread() which does
 571     // the same for the main app thread only)
 572     wxWindow *topWindow = wxTheApp->GetTopWindow();
 573     if ( topWindow )
 574     {
 575         if ( !::PostMessage(GetHwndOf(topWindow), WM_NULL, 0, 0) )
 576         {
 577             // should never happen
 578             wxLogLastError(wxT("PostMessage(WM_NULL)"));
 579         }
 580     }
 581 }
 582
 583 // ----------------------------------------------------------------------------
 584 // other wxApp event hanlders
 585 // ----------------------------------------------------------------------------
 586
 587 void wxApp::OnEndSession(wxCloseEvent& WXUNUSED(event))
 588 {
 589     if (GetTopWindow())
 590         GetTopWindow()->Close(true);
 591 }
 592
 593 // Default behaviour: close the application with prompts. The
 594 // user can veto the close, and therefore the end session.
 595 void wxApp::OnQueryEndSession(wxCloseEvent& event)
 596 {
 597     if (GetTopWindow())
 598     {
 599         if (!GetTopWindow()->Close(!event.CanVeto()))
 600             event.Veto(true);
 601     }
 602 }
 603
 604 // ----------------------------------------------------------------------------
 605 // miscellaneous
 606 // ----------------------------------------------------------------------------
 607
 608 /* static */
 609 int wxApp::GetComCtl32Version()
 610 {
 611 #if defined(__WXMICROWIN__) || defined(__WXWINCE__)
 612     return 0;
 613 #else
 614     // cache the result
 615     //
 616     // NB: this is MT-ok as in the worst case we'd compute s_verComCtl32 twice,
 617     //     but as its value should be the same both times it doesn't matter
 618     static int s_verComCtl32 = -1;
 619
 620     if ( s_verComCtl32 == -1 )
 621     {
 622         // initally assume no comctl32.dll at all
 623         s_verComCtl32 = 0;
 624
 625         // we're prepared to handle the errors
 626         wxLogNull noLog;
 627
 628 #if wxUSE_DYNLIB_CLASS
 629         // do we have it?
 630         wxDynamicLibrary dllComCtl32(_T("comctl32.dll"), wxDL_VERBATIM);
 631
 632         // if so, then we can check for the version
 633         if ( dllComCtl32.IsLoaded() )
 634         {
 635             // now check if the function is available during run-time
 636             wxDYNLIB_FUNCTION( DLLGETVERSIONPROC, DllGetVersion, dllComCtl32 );
 637             if ( pfnDllGetVersion )
 638             {
 639                 DLLVERSIONINFO dvi;
 640                 dvi.cbSize = sizeof(dvi);
 641
 642                 HRESULT hr = (*pfnDllGetVersion)(&dvi);
 643                 if ( FAILED(hr) )
 644                 {
 645                     wxLogApiError(_T("DllGetVersion"), hr);
 646                 }
 647                 else
 648                 {
 649                     // this is incompatible with _WIN32_IE values, but
 650                     // compatible with the other values returned by
 651                     // GetComCtl32Version()
 652                     s_verComCtl32 = 100*dvi.dwMajorVersion +
 653                                         dvi.dwMinorVersion;
 654                 }
 655             }
 656
 657             // if DllGetVersion() is unavailable either during compile or
 658             // run-time, try to guess the version otherwise
 659             if ( !s_verComCtl32 )
 660             {
 661                 // InitCommonControlsEx is unique to 4.70 and later
 662                 void *pfn = dllComCtl32.GetSymbol(_T("InitCommonControlsEx"));
 663                 if ( !pfn )
 664                 {
 665                     // not found, must be 4.00
 666                     s_verComCtl32 = 400;
 667                 }
 668                 else // 4.70+
 669                 {
 670                     // many symbols appeared in comctl32 4.71, could use any of
 671                     // them except may be DllInstall()
 672                     pfn = dllComCtl32.GetSymbol(_T("InitializeFlatSB"));
 673                     if ( !pfn )
 674                     {
 675                         // not found, must be 4.70
 676                         s_verComCtl32 = 470;
 677                     }
 678                     else
 679                     {
 680                         // found, must be 4.71 or later
 681                         s_verComCtl32 = 471;
 682                     }
 683                 }
 684             }
 685         }
 686 #endif
 687     }
 688
 689     return s_verComCtl32;
 690 #endif // Microwin/!Microwin
 691 }
 692
 693 // Yield to incoming messages
 694
 695 bool wxApp::Yield(bool onlyIfNeeded)
 696 {
 697     // MT-FIXME
 698     static bool s_inYield = false;
 699
 700 #if wxUSE_LOG
 701     // disable log flushing from here because a call to wxYield() shouldn't
 702     // normally result in message boxes popping up &c
 703     wxLog::Suspend();
 704 #endif // wxUSE_LOG
 705
 706     if ( s_inYield )
 707     {
 708         if ( !onlyIfNeeded )
 709         {
 710             wxFAIL_MSG( wxT("wxYield called recursively" ) );
 711         }
 712
 713         return false;
 714     }
 715
 716     s_inYield = true;
 717
 718     // we don't want to process WM_QUIT from here - it should be processed in
 719     // the main event loop in order to stop it
 720     MSG msg;
 721     while ( PeekMessage(&msg, (HWND)0, 0, 0, PM_NOREMOVE) &&
 722             msg.message != WM_QUIT )
 723     {
 724 #if wxUSE_THREADS
 725         wxMutexGuiLeaveOrEnter();
 726 #endif // wxUSE_THREADS
 727
 728         if ( !wxTheApp->Dispatch() )
 729             break;
 730     }
 731
 732     // if there are pending events, we must process them.
 733     ProcessPendingEvents();
 734
 735 #if wxUSE_LOG
 736     // let the logs be flashed again
 737     wxLog::Resume();
 738 #endif // wxUSE_LOG
 739
 740     s_inYield = false;
 741
 742     return true;
 743 }
 744
 745 #if wxUSE_EXCEPTIONS
 746
 747 // ----------------------------------------------------------------------------
 748 // exception handling
 749 // ----------------------------------------------------------------------------
 750
 751 bool wxApp::OnExceptionInMainLoop()
 752 {
 753     // ask the user about what to do: use the Win32 API function here as it
 754     // could be dangerous to use any wxWidgets code in this state
 755     switch (
 756             ::MessageBox
 757               (
 758                 NULL,
 759                 _T("An unhandled exception occurred. Press \"Abort\" to \
 760 terminate the program,\r\n\
 761 \"Retry\" to exit the program normally and \"Ignore\" to try to continue."),
 762                 _T("Unhandled exception"),
 763                 MB_ABORTRETRYIGNORE |
 764                 MB_ICONERROR|
 765                 MB_TASKMODAL
 766               )
 767            )
 768     {
 769         case IDABORT:
 770             throw;
 771
 772         default:
 773             wxFAIL_MSG( _T("unexpected MessageBox() return code") );
 774             // fall through
 775
 776         case IDRETRY:
 777             return false;
 778
 779         case IDIGNORE:
 780             return true;
 781     }
 782 }
 783
 784 #endif // wxUSE_EXCEPTIONS