diff --git a/windows/main.cpp b/windows/main.cpp
index 35be9942..4bcef139 100644
--- a/windows/main.cpp
+++ b/windows/main.cpp
@@ -115,17 +115,16 @@ int uiInit(void *options, uiInitError *err)
 void uiMain(void)
 {
 	MSG msg;
-	BOOL ret;
 	HRESULT hr;
 
 	for (;;) {
-		hr = uiprivHrGetMessageW(&msg, NULL, 0, 0, &ret);
+		hr = uiprivHrGetMessageW(&msg, NULL, 0, 0);
+		if (hr == S_FALSE)		// WM_QUIT
+			return;
 		if (hr != S_OK) {
 			// TODO log error
 			return;
 		}
-		if (ret == 0)		// WM_QUIT
-			return;
 		// TODO IsDialogMessage()
 		TranslateMessage(&msg);
 		DispatchMessageW(&msg);
diff --git a/windows/winhresult.cpp b/windows/winhresult.cpp
index cf8998d6..0b7ea0fc 100644
--- a/windows/winhresult.cpp
+++ b/windows/winhresult.cpp
@@ -41,13 +41,16 @@ HRESULT WINAPI uiprivHrCreateWindowExW(DWORD exStyle, LPCWSTR className, LPCWSTR
 	return S_OK;
 }
 
-// TODO turn ret into S_OK/S_FALSE?
-HRESULT WINAPI uiprivHrGetMessageW(LPMSG msg, HWND hwnd, UINT filterMin, UINT filterMax, BOOL *ret)
+HRESULT WINAPI uiprivHrGetMessageW(LPMSG msg, HWND hwnd, UINT filterMin, UINT filterMax)
 {
+	BOOL ret;
+
 	SetLastError(0);
-	*ret = GetMessageW(msg, hwnd, filterMin, filterMax);
-	if (*ret < 0)
+	ret = GetMessageW(msg, hwnd, filterMin, filterMax);
+	if (ret < 0)
 		return lastErrorToHRESULT();
+	if (ret == 0)
+		return S_FALSE;
 	return S_OK;
 }
 
diff --git a/windows/winhresult.hpp b/windows/winhresult.hpp
index a723f04c..a2126ce2 100644
--- a/windows/winhresult.hpp
+++ b/windows/winhresult.hpp
@@ -2,7 +2,8 @@
 
 extern HRESULT WINAPI uiprivHrRegisterClassW(const WNDCLASSW *wc);
 extern HRESULT WINAPI uiprivHrCreateWindowExW(DWORD exStyle, LPCWSTR className, LPCWSTR windowName, DWORD style, int x, int y, int width, int height, HWND parent, HMENU menu, HINSTANCE hInstance, LPVOID lpParam, HWND *hwnd);
-extern HRESULT WINAPI uiprivHrGetMessageW(LPMSG msg, HWND hwnd, UINT filterMin, UINT filterMax, BOOL *ret);
+// Note: if no error, returns S_FALSE on WM_QUIT, and S_OK otherwise.
+extern HRESULT WINAPI uiprivHrGetMessageW(LPMSG msg, HWND hwnd, UINT filterMin, UINT filterMax);
 extern HRESULT WINAPI uiprivHrPostMessageW(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
 extern HRESULT WINAPI uiprivHrLoadIconW(HINSTANCE hInstance, LPCWSTR name, HICON *hIcon);
 extern HRESULT WINAPI uiprivHrLoadCursorW(HINSTANCE hInstance, LPCWSTR name, HCURSOR *hCursor);