Clears the receiving buffer and closes the com port
COM_CLOSE(<nComPort>) --> lClosed
<nComPort> Designates which port is closed, COM1 to COMN.
A return of .T. indicates that the port is open and can be closed
This function closes one of the ports (1 to 4). This means that the
buffer is cleared, and all signals in the modem control register (MCR)
are deactivated. Characters remaining in the buffer are lost. The DTR
and RTS signals become inactive, and any existing modem connection is
Warning! All characters in the buffer are cleared, and the status
register is set to 0. Existing connections are always broken!
nCharacter := COM_COUNT(1) // How many characters in
// the buffer ?
IF nCharacter > 0
* Read everything from buffer!
cContent := COM_READ(1, nCharacter)