Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!ucsd!rutgers!modus!otello!gear!cadlab!martelli
From: martelli@cadlab.sublink.ORG (Alex Martelli)
Newsgroups: comp.lang.fortran
Subject: Re: INDEX() and "_" in FORTRAN 77 under SUN 4.1 OS
Message-ID: <890@cadlab.sublink.ORG>
Date: 4 Jun 91 08:15:26 GMT
References: <1991May31.141830.10778@xn.ll.mit.edu>
Organization: CAD.LAB, Bologna, Italia
Lines: 45

delaney@xn.ll.mit.edu (John R. Delaney) writes:
:A colleague has run into an apparent inconsistency in the way the
:underscore character is handled in the FORTRAN 77 which came with SUN's 4.1
:OS. That character is acceptable in variable names and can be printed out
:if in a string. But the INDEX function acts as if it wasn't there in the
:same strings.
:
:Is this a well-know problem or are we experiencing some sort of local
:quirk?

I think you are experiencing *several* quirks... first, no Fortran 77 compiler
comes with SunOs 4.1 - Sun Fortran is an "unbundled" program, to be purchased
separately.  It would thus be necessary to know about f77's version number -
use 'f77 -V source.f' to see version id's for each compiler pass.  With what
we have, which identifies itself as version 1.3.1, this program:
      PROGRAM PROI
*
      CALL INDEX_CHECK('FIRST_STRING', 'STST')
      CALL INDEX_CHECK('FIRST_STRING', 'ST_ST')
      CALL INDEX_CHECK('SECOND STRING', 'ND ST')
      CALL INDEX_CHECK('SECOND STRING', 'ND_ST')
      STOP
      END

      SUBROUTINE INDEX_CHECK(HAYSTACK, NEEDLE)
      CHARACTER*(*) HAYSTACK,NEEDLE
      WRITE(*,*) 'INDEX(',HAYSTACK,',',NEEDLE,')=',
     .            INDEX(HAYSTACK,NEEDLE)
      RETURN
      END

gives the following, expected output:
INDEX(FIRST_STRING,STST)=  0
INDEX(FIRST_STRING,ST_ST)=  4
INDEX(SECOND STRING,ND ST)=  5
INDEX(SECOND STRING,ND_ST)=  0

Thus, in no sense does INDEX() "act is if [the underline] wasn't there".
What does this program output for you?  What release does -V tell you that
you have?  I suspect that you may have misanalized your problem...
-- 
Alex Martelli - CAD.LAB s.p.a., v. Stalingrado 53, Bologna, Italia
Email: (work:) martelli@cadlab.sublink.org, (home:) alex@am.sublink.org
Phone: (work:) ++39 (51) 371099, (home:) ++39 (51) 250434; 
Fax: ++39 (51) 366964 (work only), Fidonet: 332/407.314 (home only).