CREATE_PROCESS
     Starts a subprocess and associates a buffer with it.
  Syntax
     process := CREATE_PROCESS (buffer [,string])
  Parameters
     buffer     The buffer for storing output from the subprocess.
     string     Optionally, a command to send to the subprocess.
  Comments
  Example
     mail_proc := CREATE_PROCESS (second_buffer, "mail");
     Creates a subprocess, specifies SECOND_BUFFER as the buffer for storing
     the output from the subprocess, and sends the DCL MAIL command as the
     first command to be executed.
  Related topics
     ATTACH   SEND   SEND_EOF   SPAWN