Description

   If the EDT session is terminated by EXIT or QUIT, the status will
   be a successful value (bit <0> = 1). If the session is terminated
   because the file was not found and if the /NOCREATE qualifier
   was in effect, the failure code EDT$_INPFILNEX is returned. In an
   unsuccessful termination caused by an EDT error, a failure code
   corresponding to that error is returned. Each error status from
   the FILEIO and WORKIO routines is explained separately.

   Three of the arguments to the EDT$EDIT routine, fileio, workio,
   and xlate are the entry point names of user-supplied routines.