SEND_EOF
     Uses features of the VMS Mailbox Driver to send an end-of-file message
     (IO$_WRITEOF) to a process or subprocess you specify.  The end-of-file
     causes an outstanding read from a subprocess to be completed with an
     SS$_ENDOFFILE status.
  Syntax
     SEND_EOF (process)
  Examples
     SEND_EOF (Joyce_1);
     Sends an end-of-file to the subprocess Joyce_1.
  Related topics
     ATTACH   CREATE_PROCESS   SEND   SPAWN