Whilst messing around with multithreading, callbacks, win32 api functions, and other troublesome troubles, I received an idea event. (hehehe)
What if, instead of defining a global (or static when designing a class) callback function, I instead assigned DefWindowProc for lpfnWndProc when registering the window class, and then ran the whole event loop on a separate thread?
This way I don't have to hack around the this problem when implementing the callback in a class
and the main thread's execution continues, freeing you from that god-forsaken while loop, allowing you to do whatever, even open another window (yay!)
The "normal" way:
LRESULT CALLBACK WndProc(...)
{
... // process event information
return DefWindowProc(...);
}
int CALLBACK WinMain(...)
{
... // initialize whatever needs initializing :)
WNDCLASSEX wc;
...
wc.lpfnWndProc = WndProc;
... // register the class, create the window, etc...
MSG msg;
while(GetMessage(&msg, 0, 0, 0) != 0)
{
... // TranslateMessage(&msg) if you want/need it
DispatchMessage(&msg); // dispatches the message to WndProc
}
return static_cast<int>(msg.wParam);
}
My newfound awesome way:
DWORD WINAPI MyAwesomeEventLoop(void* data) // must be static in a class
{
... // do whatever you need with the data
MSG msg;
while(GetMessage(&msg, 0, 0, 0) != 0)
{
... // TranslateMessage(&msg) if you want/need it
... // process event information
// call PostQuitMessage(0) to leave the loop
}
return static_cast<DWORD>(msg.wParam);
}
int CALLBACK WndProc(...)
{
...
WNDCLASSEX wc;
...
wc.lpfnWndProc = DefWindowProc;
...
HANDLE threadHandle = 0;
// use "this" as the 4th parameter when implementing in a class
threadHandle = CreateThread(0, 0, MyAwesomeEventLoop, 0, 0, 0);
... // you are now free to do whatever you want! :)
// waits untill the thread finishes
// hopefully because PostQuitMessage(0) was called
WaitForSingleObject(threadHandle, INFINITE);
DWORD returnValue = 0;
GetExitCodeThread(threadHandle, &returnValue);
CloseHandle(threadHandle);
...
return static_cast<int>(returnValue);
}
What do you guys think?
