*+
*  Name:
*     NDF_ELB

*  Purpose:
*     Define the NDF_ system Error Logging Block (ELB).

*  Language:
*     Starlink Fortran 77

*  Type of Module:
*     Global variables include file.

*  Description:
*     This file defines global variables which are used to log error
*     messages for subsequent recording in NDF history records.

*  Notes:
*     In use, a snapshot of the current EMS error stack is recorded in
*     this block by the routine NDF1_HLERR and subsequently appended to
*     an NDF's current history record by the routine NDF1_HDERR.

*  Prior Requirements:
*     The NDF_CONST and EMS__PAR include files should be included
*     before this file, in order to define constants used here.

*  Copyright:
*     Copyright (C) 1993 Science & Engineering Research Council

*  Authors:
*     RFWS: R.F. Warren-Smith (STARLINK)
*     {enter_new_authors_here}

*  History:
*     15-JUN-1993 (RFWS):
*        Original version.
*     {enter_changes_here}

*-

*  Global Variables:

*  List of pending error messages (most recently reported first).
      CHARACTER * ( EMS__SZMSG ) ELB_MSG( NDF__MXERR )

*  Number of pending EMS error messages (zero indicates no error).
      INTEGER ELB_NERR

*  Current EMS error status value (associated with the most recently
*  reported error message).
      INTEGER ELB_STAT

*  Common blocks.
*  =============

*  Non-character values.
      COMMON /NDF1_ELB1/ ELB_NERR, ELB_STAT

*  Character values.
      COMMON /NDF1_ELB2/ ELB_MSG

*  Save common block contents.
      SAVE /NDF1_ELB1/
      SAVE /NDF1_ELB2/

*.
