gistfile1.txt

void SetWindowTransparent(HWND hWnd, unsigned char alpha)
{
	BOOL (*pSetLayeredWindowAttributes)(HWND, COLORREF,  BYTE, DWORD) = NULL;
	HMODULE hDll = LoadLibrary(_T("\\Windows\\coredll.dll"));
	pSetLayeredWindowAttributes = (BOOL (*)(HWND, COLORREF,  BYTE, DWORD))GetProcAddress(hDll, _T("SetLayeredWindowAttributes"));

	LONG style = GetWindowLong(hWnd, GWL_EXSTYLE);
	SetWindowLong(hWnd, GWL_EXSTYLE, style | WS_EX_LAYERED);
	pSetLayeredWindowAttributes(hWnd, 0, alpha, LWA_ALPHA);

	FreeLibrary(hDll);
}