C$Procedure                        OPSFOR
C
      SUBROUTINE OPSFOR ( UNIT , FILE , ERROR )
C
C
C*******************************************************************************
C
C       Copyright (C) 1993, California Institute of Technology.  U.S.
C       Government Sponsorhip under NASA Contract NAS7-918 is
C       acknowledged.
C
C*******************************************************************************
C
C$ Purpose
C
C  OPSFOR opens a sequential, formatted, old, readonly file. 
C
C  For example, when opening a file to read one or more namelist.
C
C$ Log
C
C  22-Apr-1988
C  Eric Cannell - birth
C
C$ Input_Arguments
C
C  UNIT   - FORTRAN unit number
C  FILE   - file name
C
C$ Output_Arguments
C
C  ERROR  - set .FALSE. if file was opened successfully. Otherwise,
C           .TRUE.
C
C$ Files
C
C  FILE - UNIT - sequential, formatted, old, readonly file
C  
C$ Declarations_of_Input_and_Output_Arguments
C
      LOGICAL              ERROR
      CHARACTER*(*)        FILE
      INTEGER              UNIT
C
C$ Method
C-&

C1    Set error flag to false.

      ERROR = .FALSE.

C1    Attempt to open file.

      OPEN ( 
     &       UNIT     = UNIT,
     &       FILE     = FILE,
     &       ACCESS   = 'SEQUENTIAL',
     &       FORM     = 'FORMATTED',
     &       STATUS   = 'OLD',
     &       READONLY,
     &       ERR      = 998
     &     )

      GOTO 999

C1    Set error flag to true if there was a problem.

998   CONTINUE

      ERROR = .TRUE.

C1    Return status.

999   CONTINUE

      RETURN
      END