windows: use waitable timers

gral_windows.cpp

@@ -203,6 +203,7 @@ struct WindowData {
 struct gral_timer {
 	void (*callback)(void *user_data);
 	void *user_data;
+	HANDLE timer;
 };
 
 
@@ -1064,16 +1065,25 @@ void gral_window_clipboard_paste(gral_window *window, void (*callback)(char cons
 	CloseClipboard();
 }
 
+static void CALLBACK timer_completion_routine(LPVOID lpArgToCompletionRoutine, DWORD dwTimerLowValue, DWORD dwTimerHighValue) {
+	gral_timer *timer = (gral_timer *)lpArgToCompletionRoutine;
+	timer->callback(timer->user_data);
+}
+
 gral_timer *gral_window_create_timer(gral_window *window, int milliseconds, void (*callback)(void *user_data), void *user_data) {
 	gral_timer *timer = new gral_timer();
 	timer->callback = callback;
 	timer->user_data = user_data;
-	SetTimer((HWND)window, (UINT_PTR)timer, milliseconds, NULL);
+	timer->timer = CreateWaitableTimer(NULL, FALSE, NULL);
+	LARGE_INTEGER due_time;
+	due_time.QuadPart = milliseconds * -10000;
+	SetWaitableTimer(timer->timer, &due_time, milliseconds, &timer_completion_routine, timer, FALSE);
 	return timer;
 }
 
 void gral_window_delete_timer(gral_window *window, gral_timer *timer) {
-	KillTimer((HWND)window, (UINT_PTR)timer);
+	CancelWaitableTimer(timer->timer);
+	CloseHandle(timer->timer);
 	delete timer;
 }