DispatchMessage - synchronous or asynchronous

DispatchMessage is synchronous function.

下面是兩個例子，用于說明為什麼是同步的：給人異步的錯覺，是因為喚起了一個新的消息循環

while (GetMessage (&msg, NULL, , ))  
{ 
        if (! TranslateAccelerator (msg.hwnd, hAccelTable, &msg))  
        { 
            TranslateMessage (&msg); 
            DispatchMessage (&msg); 
        }
}
//case 1：
LRESULT CALLBACK WndProc (HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) 
{ 
   int wmId, wmEvent; 
   switch (message)  
     { 
       case WM_COMMAND: 
            break; 
       case WM_MOUSEMOVE: 
       //MessageBox organizes the message loop
            MessageBox (NULL, "aa", "aa", MB_OK); 
            ExitProcess (); 
            break; 
       case WM_DESTROY: 
            PostQuitMessage (); 
            break; 
       default: 
            return DefWindowProc (hWnd, message, wParam, lParam); 
     }
   return ; 
}
//case 2：
LRESULT CALLBACK WndProc (HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) 
{ 
   int wmId, wmEvent; 
   switch (message)  
     { 
       case WM_COMMAND: 
            break; 
       case WM_MOUSEMOVE: 
            Sleep (INFINITE); 
            DebugBreak ();
            break; 
       case WM_DESTROY: 
            PostQuitMessage (); 
            break; 
       default: 
            return DefWindowProc (hWnd, message, wParam, lParam); 
     }
   return ; 
}