ComForceXoff

ComForceXoff forces flow control to be invoked on the remote transmitter to prevent it from transmitting more data. If XON/XOFF flow control is used by the port, then an XOFF is sent. If RTS/CTS flow control is used, then RTS is lowered. If DTR/DSR flow control is used, then DTR is lowered.

If the port does not have any flow control method selected, this function is a no-operation.

Syntax:          err_t far ComForceXoff(handle_t Handle)
Parameters:      handle_t Handle The handle returned via a successful ComOpen.  
Returns:         0 - if successful 
                 Any other value indicates an error condition.  
                 ENOTYOURS - The specified port has not been acquired by the calling 
                             application.  
Comments:        ComOpen() must first be called in order to get a valid handle to the 
                 communications port.  

                 Note that this function cannot guarantee that the remote transmitter 
                 is well-behaved and will actually stop transmissions.  In many 
                 cases--even for well behaved hosts--one or more bytes may arrive 
                 after flow control is asserted.