C 
C Subroutines to handle error and warning messages
C
C Version: 5.20
C Date: 1998, November 3
C
C Coded by: Ludek Klimes
C     Department of Geophysics, Charles University Prague,
C     Ke Karlovu 3, 121 16 Praha 2, Czech Republic,
C     E-mail: klimes@seis.karlov.mff.cuni.cz
C
C.......................................................................
C
C This file consists of:
C     ERROR...Subroutine to handle the error conditions indicated within
C             the Fortran code.  It writes a brief error message and
C             STOPs the program.  A user is encouraged to modify this
C             routine to redirect the error mesage or to STOP the
C             program in a different way.
C             ERROR
C     WARN... Subroutine to handle the warning messages indicated within
C             the Fortran code.  It writes a brief error message and
C             PAUSEs the program.  A user is encouraged to modify this
C             routine to redirect the warning mesage or to change the
C             PAUSE statement.
C             WARN
C     LUWARN..Integer external function to remember the logical unit
C             number of the output file to write the warning messages.
C             LUWARN
C
C=======================================================================
C
C     
C
      SUBROUTINE ERROR(TEXT)
      CHARACTER*(*) TEXT
C
C Subroutine to handle the error conditions indicated within the Fortran
C code.  It writes a brief error message and STOPs the program.
C A user is encouraged to modify this routine to redirect the error mesage
C or to STOP the program in a different way.
C
C Input:
C     TEXT... A brief text identifying the error.
C             Example: 'PRG-04: Too small array AAA', where PRG-04
C             identifies the corresponding error in program PRG.
C             Subroutine ERROR prepends string 'Error ' to TEXT.
C No output.
C
C Date: 1998, November 3
C Coded by Ludek Klimes
C
C-----------------------------------------------------------------------
C
      EXTERNAL LUWARN
      INTEGER  LUWARN
C
C     If a formatted output log file is open, a copy of the error
C     message is written there:
      IF (LUWARN(0).GT.0) THEN
        WRITE(LUWARN(0),'(2A)') ' Error ',TEXT
      END IF
C
C     The error message is written to the standard output:
      WRITE(*,'(2A)') ' Error ',TEXT
C
C     PAUSE command may enable to terminate batch files or scripts on
C     some systems:
      PAUSE 999
C
C     Finally, the program must be STOPped:
      STOP 999
      END
C
C=======================================================================
C
C     
C
      SUBROUTINE WARN(TEXT)
      CHARACTER*(*) TEXT
C
C Subroutine to handle the error conditions indicated within the Fortran
C code.  It writes a brief error message and STOPs the program.
C A user is encouraged to modify this routine to redirect the error mesage
C or to STOP the program in a different way.
C Subroutine to handle the warning messages indicated within the Fortran
C code.  It writes a brief error message and PAUSEs the program.
C A user is encouraged to modify this routine to redirect the warning
C mesage or to change the PAUSE statement.
C
C Input:
C     TEXT... A brief text identifying the warning.
C             Example: 'PRG-05: No header section found', where PRG-05
C             identifies the corresponding warning in program PRG.
C             Subroutine WARN prepends string 'Warning ' to TEXT.
C No output.
C
C Date: 1998, November 3
C Coded by Ludek Klimes
C
C-----------------------------------------------------------------------
C
      EXTERNAL LUWARN
      INTEGER  LUWARN
C
C     If a formatted output log file is open, a copy of the warning
C     message is written there:
      IF (LUWARN(0).GT.0) THEN
        WRITE(LUWARN(0),'(2A)') ' Warning ',TEXT
      END IF
C
C     The error message is written to the standard output:
      WRITE(*,'(2A)') ' Warning ',TEXT
C
C     PAUSE command to suspend the execution:
      PAUSE
C
      RETURN
      END
C
C=======================================================================
C
C     
C
      INTEGER FUNCTION LUWARN(LU)
      INTEGER LU
C
C Function to remember the logical unit number of the output file to
C write the warning, error and other messages to output log file,
C if it is defined.
C
C Input:
C     LU...   LU positive:
C               LUWARN is redefined to LU.  LU should represent the
C               logical unit number of the formatted output log file to
C               write the messages.  Function LUWARN with such a value
C               of LU should be called after opening the output log file
C               which is usually performed from the main program.
C             Otherwise:
C               LUWARN is the last redefined value.  LUWARN=0 when
C               starting the program.
C Output:
C     LUWARN..Logical unit number of the output log file to write the
C             warning messages.
C             LUWARN positive: formatted output log file is ready,
C             LUWARN=0: output log file is not available.
C
C Example:
C     First invocation:
C             OPEN(LULOG,FILE=FLOG)
C             LULOG=LUWARN(LULOG)
C     Next invocations:
C             IF (LUWARN(0).GT.0) THEN
C               WRITE(LUWARN(0),'(2A)') ' Error ',TEXT
C             END IF
C
C Note:
C     For consistency, it is recommended that an error message starts
C     with string ' Error ' at the begining of the first written line
C     immediately followed by the string identifying the error, and
C     a warning message starts with string ' Warning'.
C     Numbered warnings should be listed in the list of errors.
C
C Date: 1997, November 22
C Coded by Ludek Klimes
C
C-----------------------------------------------------------------------
C
      INTEGER LUSTOR
      SAVE    LUSTOR
      DATA    LUSTOR/0/
C
      IF(LU.GT.0) THEN
        LUSTOR=LU
      END IF
      LUWARN=LUSTOR
      RETURN
      END
C
C=======================================================================
C