catching Errors in OS callbacks how to print stack trace?

NaN divide at by.zero
Mon Feb 24 13:42:01 UTC 2020


Normally a failed assert gives the file, line number and a stack 
trace, but I hit one today that just prints..

assertion failure

Im sure it is because it's in the WindowProc callback from the 
OS. As the callback is nothrow you need to catch and handle 
anything there, you have to catch all throwables or else it just 
hangs when you hit an assert. But how do I get it to print the 
full file, line, and stack trace?

Here's my window proc...

extern(Windows)
LRESULT WindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM 
lparam) nothrow
{
     try
     {
         auto window = cast(Window) (cast(void*) 
GetWindowLongPtr(hwnd, 0));

         if (window is null)
             return DefWindowProcA(hwnd, msg, wparam, lparam);
         else
             return window.windowProc(msg, wparam, lparam);
     }
     catch (Throwable e)
     {
         try { writeln(e.msg); }
         catch(Exception what) {}
         PostQuitMessage(0);
         return 0;
     }
}




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