[Mingw-users] Dwarf exception handling and Windows programming

[Oscar F. <of...@wa...>]

Hi.

I've discovered that programs built with MinGW's g++ 3.2 dies with
'abnormal program termination' when a Windows callback throws an
exception.

The trivial Windows GUI program attached below works fine with MinGW
gcc 2.95.3-6, FSF gcc 3.1 configured with --enable-sjlj-exceptions,
Borland 5.5.1 and MSVC++ 6 sp4

Build, execute, click on the 'close window' box, say 'no'.

Of course, I've discovered the problem while working on a "real world"
application <g>. This is a serious drawback.

The question: is dwarf exception handling supposed to work across
Windows callbacks?

If the answer to the above is 'No', IMHO MinGW should go back to sjlj
exceptions.

-- 
Oscar

// Begin file foo.cpp
#include <windows.h>

#include <string.h>

const char *CLASSNAME = "Tutorial", *WINNAME = "Tutorial 2 - The Window";

LRESULT CALLBACK WndProc(HWND hWnd, unsigned int iMessage, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR, int nCmdShow)
{
  HWND hWnd;
  MSG Message;
  WNDCLASS WndClass;
  memset(&WndClass, 0, sizeof(WndClass));
  WndClass.cbClsExtra = 0;
  WndClass.cbWndExtra = 0;
  WndClass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
  WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
  WndClass.hIcon = LoadIcon(hInstance, NULL);
  WndClass.hInstance = hInstance;
  WndClass.lpfnWndProc = WndProc;
  WndClass.lpszClassName = CLASSNAME;
  WndClass.style = CS_HREDRAW | CS_VREDRAW;
  if(!RegisterClass(&WndClass))
    return 0;
       
  hWnd = CreateWindow(CLASSNAME, WINNAME, WS_OVERLAPPEDWINDOW,
                      CW_USEDEFAULT, CW_USEDEFAULT, 300, 100,
                      NULL, NULL, hInstance, NULL);   
  ShowWindow(hWnd, nCmdShow);

  try {
    while(GetMessage(&Message, hWnd, 0, 0))
    {
      TranslateMessage(&Message);
      DispatchMessage(&Message);
    }
  }
  catch(...) {
    MessageBox(0, "Exception", "Exception", MB_OK);
  }
  
  return Message.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage, WPARAM wParam, LPARAM lParam)
{
  switch(iMessage)
  {
  case WM_CLOSE:
  case WM_DESTROY:
    if(MessageBox(hWnd, "Do you really want to quit?", "Message", MB_YESNO) == IDYES)
      PostQuitMessage(0);
    else
      throw 10;
    break;
  default:
    return DefWindowProc(hWnd, iMessage, wParam, lParam);
  }
  return 0;
}
// End of file foo.cpp