GetMessage not responding when I am in another window

[logorman]

I have a C++ Windows program that produces a window and performs a GetMessage() loop to change that window upon a mouse/keyboard event or an event that a file has changed. It works great except when I bring up another window to change the file my program is waiting on -- to test it. When I change the file in another window, my program does not react to this until I move my mouse back over my program window (i.e., I don't even have to click on that window to make it the focus). Is there some parameter I can set to have my program react immediately to events even though I'm in another window?

I've included the message loop part of my C++ code to show my intention.

/* Main message loop - respond to either a mouse/keyboard event, or file change */
  while (GetMessage(&msg, NULL, 0, 0)) {	       // get windows messages
    iRslt = checkFileChange (SPEECH_FILE);           // iRslt =1 if SPEECH_FILE changed
    if (iRslt == 1) {
//    PostMessage( hWnd, WM_FILECHANGE, NULL, NULL );	// does nothing
      msg.message = WM_FILECHANGE;
      fprintf (fpOut, "MAIN LOOP: file change%d\n");                // for debugging
    }
    TranslateMessage(&msg);
    DispatchMessage(&msg);		
  }
  CoUninitialize();

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