This function closes the pipe to the Comm Engine.
The command format is as follows:
rc = CLClosePipe( '0' )
This function returns the same values as the API call DosClose. The values
of most interest are:
0 NO_ERROR
2 ERROR_FILE_NOT_FOUND
5 ERROR_ACCESS_DENIED
6 ERROR_INVALID_HANDLE
See the example CMD files included for details on how to run a pipe to the Comm Engine.