SLATEC Routines --- XERPRN ---

*DECK XERPRN
      SUBROUTINE XERPRN (PREFIX, NPREF, MESSG, NWRAP)
C***BEGIN PROLOGUE  XERPRN
C***SUBSIDIARY
C***PURPOSE  Print error messages processed by XERMSG.
C***LIBRARY   SLATEC (XERROR)
C***CATEGORY  R3C
C***TYPE      ALL (XERPRN-A)
C***KEYWORDS  ERROR MESSAGES, PRINTING, XERROR
C***AUTHOR  Fong, Kirby, (NMFECC at LLNL)
C***DESCRIPTION
C
C This routine sends one or more lines to each of the (up to five)
C logical units to which error messages are to be sent.  This routine
C is called several times by XERMSG, sometimes with a single line to
C print and sometimes with a (potentially very long) message that may
C wrap around into multiple lines.
C
C PREFIX  Input argument of type CHARACTER.  This argument contains
C         characters to be put at the beginning of each line before
C         the body of the message.  No more than 16 characters of
C         PREFIX will be used.
C
C NPREF   Input argument of type INTEGER.  This argument is the number
C         of characters to use from PREFIX.  If it is negative, the
C         intrinsic function LEN is used to determine its length.  If
C         it is zero, PREFIX is not used.  If it exceeds 16 or if
C         LEN(PREFIX) exceeds 16, only the first 16 characters will be
C         used.  If NPREF is positive and the length of PREFIX is less
C         than NPREF, a copy of PREFIX extended with blanks to length
C         NPREF will be used.
C
C MESSG   Input argument of type CHARACTER.  This is the text of a
C         message to be printed.  If it is a long message, it will be
C         broken into pieces for printing on multiple lines.  Each line
C         will start with the appropriate prefix and be followed by a
C         piece of the message.  NWRAP is the number of characters per
C         piece; that is, after each NWRAP characters, we break and
C         start a new line.  In addition the characters '$$' embedded
C         in MESSG are a sentinel for a new line.  The counting of
C         characters up to NWRAP starts over for each new line.  The
C         value of NWRAP typically used by XERMSG is 72 since many
C         older error messages in the SLATEC Library are laid out to
C         rely on wrap-around every 72 characters.
C
C NWRAP   Input argument of type INTEGER.  This gives the maximum size
C         piece into which to break MESSG for printing on multiple
C         lines.  An embedded '$$' ends a line, and the count restarts
C         at the following character.  If a line break does not occur
C         on a blank (it would split a word) that word is moved to the
C         next line.  Values of NWRAP less than 16 will be treated as
C         16.  Values of NWRAP greater than 132 will be treated as 132.
C         The actual line length will be NPREF + NWRAP after NPREF has
C         been adjusted to fall between 0 and 16 and NWRAP has been
C         adjusted to fall between 16 and 132.
C
C***REFERENCES  R. E. Jones and D. K. Kahaner, XERROR, the SLATEC
C                 Error-handling Package, SAND82-0800, Sandia
C                 Laboratories, 1982.
C***ROUTINES CALLED  I1MACH, XGETUA
C***REVISION HISTORY  (YYMMDD)
C   880621  DATE WRITTEN
C   880708  REVISED AFTER THE SLATEC CML SUBCOMMITTEE MEETING OF
C           JUNE 29 AND 30 TO CHANGE THE NAME TO XERPRN AND TO REWORK
C           THE HANDLING OF THE NEW LINE SENTINEL TO BEHAVE LIKE THE
C           SLASH CHARACTER IN FORMAT STATEMENTS.
C   890706  REVISED WITH THE HELP OF FRED FRITSCH AND REG CLEMENS TO
C           STREAMLINE THE CODING AND FIX A BUG THAT CAUSED EXTRA BLANK
C           LINES TO BE PRINTED.
C   890721  REVISED TO ADD A NEW FEATURE.  A NEGATIVE VALUE OF NPREF
C           CAUSES LEN(PREFIX) TO BE USED AS THE LENGTH.
C   891013  REVISED TO CORRECT ERROR IN CALCULATING PREFIX LENGTH.
C   891214  Prologue converted to Version 4.0 format.  (WRB)
C   900510  Added code to break messages between words.  (RWC)
C   920501  Reformatted the REFERENCES section.  (WRB)
C***END PROLOGUE  XERPRN