      FUNCTION NMSUB(LUNIT)

C$$$  SUBPROGRAM DOCUMENTATION BLOCK
C
C SUBPROGRAM:    NMSUB
C   PRGMMR: WOOLLEN          ORG: NP20       DATE: 1994-01-06
C
C ABSTRACT: THIS FUNCTION RETURNS THE NUMBER OF SUBSETS IN A BUFR
C   MESSAGE OPEN FOR INPUT VIA A PREVIOUS CALL TO BUFR ARCHIVE LIBRARY
C   SUBROUTINE READMG OR EQUIVALENT.  THE SUBSETS THEMSELVES DO NOT
C   HAVE TO BE READ.
C
C PROGRAM HISTORY LOG:
C 1994-01-06  J. WOOLLEN -- ORIGINAL AUTHOR
C 1998-07-08  J. WOOLLEN -- REPLACED CALL TO CRAY LIBRARY ROUTINE
C                           "ABORT" WITH CALL TO NEW INTERNAL BUFRLIB
C                           ROUTINE "BORT"
C 1999-11-18  J. WOOLLEN -- THE NUMBER OF BUFR FILES WHICH CAN BE
C                           OPENED AT ONE TIME INCREASED FROM 10 TO 32
C                           (NECESSARY IN ORDER TO PROCESS MULTIPLE
C                           BUFR FILES UNDER THE MPI)
C 2003-11-04  S. BENDER  -- ADDED REMARKS/BUFRLIB ROUTINE
C                           INTERDEPENDENCIES
C 2003-11-04  D. KEYSER  -- UNIFIED/PORTABLE FOR WRF; ADDED
C                           DOCUMENTATION (INCLUDING HISTORY); OUTPUTS
C                           MORE COMPLETE DIAGNOSTIC INFO WHEN ROUTINE
C                           TERMINATES ABNORMALLY
C
C USAGE:    NMSUB (LUNIT)
C   INPUT ARGUMENT LIST:
C     LUNIT    - INTEGER: FORTRAN LOGICAL UNIT NUMBER FOR BUFR FILE
C
C   OUTPUT ARGUMENT LIST:
C     NMSUB    - INTEGER: NUMBER OF SUBSETS IN BUFR MESSAGE
C
C REMARKS:
C    THIS ROUTINE CALLS:        BORT     STATUS
C    THIS ROUTINE IS CALLED BY: UFBMNS   UFBPOS   UFBTAB   UFBTAM
C                               Also called by application programs.
C
C ATTRIBUTES:
C   LANGUAGE: FORTRAN 77
C   MACHINE:  PORTABLE TO ALL PLATFORMS
C
C$$$

      INCLUDE 'bufrlib.prm'

      COMMON /MSGCWD/ NMSG(NFILES),NSUB(NFILES),MSUB(NFILES),
     .                INODE(NFILES),IDATE(NFILES)

C-----------------------------------------------------------------------
C-----------------------------------------------------------------------

      NMSUB = 0

C  CHECK THE FILE STATUS
C  ---------------------

      CALL STATUS(LUNIT,LUN,IL,IM)
      IF(IL.EQ.0) GOTO 900
      IF(IL.GT.0) GOTO 901
      IF(IM.EQ.0) GOTO 902

      NMSUB = MSUB(LUN)

C  EXITS
C  -----

      RETURN
900   CALL BORT('BUFRLIB: NMSUB - INPUT BUFR FILE IS CLOSED, IT MUST '//
     . 'BE OPEN FOR INPUT')
901   CALL BORT('BUFRLIB: NMSUB - INPUT BUFR FILE IS OPEN FOR OUTPUT,'//
     . ' IT MUST BE OPEN FOR INPUT')
902   CALL BORT('BUFRLIB: NMSUB - A MESSAGE MUST BE OPEN IN INPUT '//
     . 'BUFR FILE, NONE ARE')
      END
