SendMessage( hWnd, nMsg, nParam, xParam) -> < nResult >
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 PARAMETER:

  <hwnd>        Identifies the window to which the message will be sent. 
                If this parameter is HWND_BROADCAST ( -1 ), the message 
                will be sent to all top-level windows, including disabled or 
                invisible unowned windows. 

  <nMsg>        specifies the message to be sent. 

  <nparam>      first integer message parameter     

  <xParam>      second message parameter, either numeric or string



 DESCRIPTION:

  SendMessage directs Windows to send a message directly to the given
  window procedure, bypassing the application's message queue. 
  Windows does not return control to the calling application until the 
  window procedure, that receives the message, processes it or returns 
  control as a result of a call to the ReplyMessage function. 
  This is in contrast to the PostMessage function, which posts the 
  message in the window's message queue and returns immediately. 


 RETURNS:

  When an application transmits a message, it must do so by calling 
  SendMessage, if the application relies on the ( numeric ) return value 
  of a message. 
  The return value of SendMessage is the value returned by the window 
  procedure ( ::HandleEvent ) that processed the message.