SendMessageTimeout takes a DWORD_PTR not a DWORD.

dlls/ole32/tests/marshal.c

@@ -1324,7 +1324,7 @@ static HRESULT WINAPI TestRE_IClassFactory_CreateInstance(
     REFIID riid,
     LPVOID *ppvObj)
 {
-    DWORD res;
+    DWORD_PTR res;
     BOOL ret = SendMessageTimeout(hwnd_app, WM_NULL, 0, 0, SMTO_BLOCK, 5000, &res);
     ok(ret, "Timed out sending a message to originating window during RPC call\n");
     return S_FALSE;

dlls/user/message.c

@@ -3426,6 +3426,6 @@ BOOL WINAPI GetGUIThreadInfo( DWORD id, GUITHREADINFO *info )
  */
 BOOL WINAPI IsHungAppWindow( HWND hWnd )
 {
-    DWORD dwResult; 
-    return !SendMessageTimeoutA(hWnd, WM_NULL, 0, 0, SMTO_ABORTIFHUNG, 5000, &dwResult);	
+    DWORD_PTR dwResult;
+    return !SendMessageTimeoutA(hWnd, WM_NULL, 0, 0, SMTO_ABORTIFHUNG, 5000, &dwResult);
 }

dlls/user/user_main.c

@@ -374,7 +374,7 @@ BOOL WINAPI ExitWindowsEx( UINT flags, DWORD reason )
         {
             HWND *phwnd;
             UINT send_flags;
-            DWORD result;
+            DWORD_PTR result;
 
             /* Send a WM_QUERYENDSESSION message to every window */
             send_flags=(flags & EWX_FORCEIFHUNG) ? SMTO_ABORTIFHUNG : SMTO_NORMAL;