Path: utzoo!attcan!uunet!snorkelwacker!usc!zaphod.mps.ohio-state.edu!rpi!batcomputer!riley
From: riley@batcomputer.tn.cornell.edu (Daniel S. Riley)
Newsgroups: comp.lang.fortran
Subject: Re: What is the FORTRAN for ?
Keywords: FORTRAN
Message-ID: <10583@batcomputer.tn.cornell.edu>
Date: 26 Jul 90 17:41:21 GMT
References: <1990Jul25.174153.16896@ecn.purdue.edu> <11029@chaph.usc.edu>
Reply-To: riley@tcgould.tn.cornell.edu (Daniel S. Riley)
Organization: Cornell Theory Center, Cornell University, Ithaca NY
Lines: 26

In article <11029@chaph.usc.edu> ajayshah@aludra.usc.edu (Ajay Shah) writes:
>Honestly, I can't imagine why Fortran is half as popular as it
>is.  All old libraries can be linked into Pascal/C programs these
>days, which removes the only "fundamental" reason to hang on with
>fortran.

There's no standard for calling sequences from C to FORTRAN, especially
for CHARACTER arguments.  Our code has to run under VAX/VMS, IBM VM/CMS,
Ultrix, Unix, AIX, and so on--so portability is important, and cross
language calls are not currently portable.

As people have already mentioned, there are optimizations that FORTRAN 
compilers can make which C compilers cannot (due to things like aliasing
of subroutine types, and pointers).  In addition, C (last I looked) doesn't
guarantee the order of evaluation of expressions--the compiler reserves
the right to commute and associate regardless of parentheses and such...so
you sometimes have to split expressions up into lots of little pieces to
force a particular order of evaluation.  This makes C less natural than
you might expect for some kinds of numerical calculations.

I agree that FORTRAN is an upleasant language to use (especially if you
stick to ANSI standard F77 for portability reasons), but there are still
valid reasons to use it.

-Dan Riley (riley@tcgould.tn.cornell, cornell!batcomputer!riley)
-Wilson Lab, Cornell University