Thread: What is wrong with this simple program? runs in the background and takes all of cpu

I suspect that for some reason the window isn't being destroyed properly. I have done many simple windows programs like this in the past and I am not sure why this one all of a sudden is acting up on me. It keeps running in the background even when I close the window, and it uses %100 of my processor so everything else in windows runs really slow.

Code:

#include <windows.h>


LRESULT CALLBACK MainWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd ){
	HWND Uber;
	MSG msg;
	WNDCLASSEX wc;
	wc.cbClsExtra = 0;
	wc.cbSize = sizeof(WNDCLASSEX);
	wc.cbWndExtra = 0;
	wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wc.hCursor = LoadCursor(hInstance, IDC_CROSS);
	wc.hIcon = LoadIcon(hInstance, IDI_ERROR);
	wc.hIconSm = NULL;
	wc.hInstance = hInstance;
	wc.lpfnWndProc = MainWndProc;
	wc.lpszClassName = "Main Window";
	wc.lpszMenuName = "Main Window";
	wc.style = CS_HREDRAW | CS_VREDRAW;
	
	if(!RegisterClassEx(&wc)) {
		MessageBox(NULL, "Could not initialize window", "ERROR", MB_OK);
		return ERROR;
	}
	
	if(!(Uber = CreateWindowEx(NULL, "Main Window", "Main Window", WS_SYSMENU |  WS_MAXIMIZEBOX | WS_MINIMIZEBOX, 
							   0, 0, 
							   CW_USEDEFAULT, CW_USEDEFAULT, 
							   NULL, NULL, hInstance, NULL))) {
							   MessageBox(NULL, "Could not initialize window", "ERROR", MB_OK);
								return ERROR;						   
	}
	
	ShowWindow(Uber, nShowCmd);
	UpdateWindow(Uber);

	while(GetMessage(&msg, Uber, 0, 0)) { 
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return 0;
}

LRESULT CALLBACK MainWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
	switch(message) {
	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	default:
		return DefWindowProc(hWnd, message, wParam, lParam);
	}
}

Your code looks pretty neat to me..

And I just guess here but try to replace the WM_DESTROY with WM_QUIT

As PostQuitMessage sends a WM_DESTROY to your window... which kind of results in an infinite loop loop loop loop loop loop

OOPS... forget about it

/ignore me - sorry

What about this idea ?

WM_DESTROY is never received by your app as you never call DestroyWindow ?

/ I better stop rambling /

LOL

Hmm I was thinking that my code looked fine too! I guess I need to just kick my computer or something because I cannot figure out why it is still running in the background even when I close it.

PostQuitMessage() generates a WM_QUIT, and then WM_QUIT message in turn is supposed to supply a false condition thus ending the loop.

Oddly enough I just changed the second parameter in GetMessage from Uber (My Uber(Ultimate Parent) Window) to null so that it now looks like:

Code:

	while(GetMessage(&msg, NULL, 0, 0)) {

I am not done though, I would like to know exactly why changing that second parameter to NULL works, but putting in an instance of HWND doesn't.