Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!umd5!uflorida!novavax!hcx1!hcx2!bill
From: bill@hcx2.SSD.HARRIS.COM
Newsgroups: comp.lang.fortran
Subject: Re: fortran problem
Message-ID: <44400020@hcx2>
Date: 13 Jun 88 15:39:00 GMT
Lines: 40
Nf-ID: #R:<8806111222.AA06982@jade.berkele:-38:hcx2:44400020:000:1973
Nf-From: hcx2.SSD.HARRIS.COM!bill    Jun 13 11:39:00 1988


/* Written  8:22 am  Jun 11, 1988 by AER7101@TECHNION.BITNET.UUCP in hcx2:comp.lang.fortran */
/* ---------- "fortran problem" ---------- */

> Hello,
> I have some questions concerning a bug (or  as I call it, when it
> bares the name of a big manufacturer, an undocumented feature..).
> I ran the following program on several machines. There is "some problem"
> with the program, as in the subroutine, an attempt is made to redefine
> a constant.
> Naively enough, I expected to get a reasonably clear message in English,
> 
> Can anyone tell me if/what the ANSI standard "says" to such a situation?
> How about the 8x draft ?
/* End of text from hcx2:comp.lang.fortran */

The Standard says (Section 15.9.2), "Actual arguments may be constants,
symbolic names of constants, function references, expressions involving
operators, and expressions enclosed in parentheses if and only if the
associated dummy argument is a variable that is not defined during
execution of the referenced external procedure."

The 8x draft says essentially the same thing, in quite a different way,
but it also (at least, at the moment) provides you with INTERFACE blocks
that can declare the INTENT of each argument, giving the compiler the
opportunity of giving a more meaningful error message in this situation.
If you choose not to use INTERFACE, though, you're back to F77.

As has been pointed out about a zillion times, the Standard says
absolutely nothing about what errors the FORTRAN processor (compiler,
linker, loader, et al.) must give for programs that violate some
restriction other than a syntax rule.  It says only what is a
standard-conforming program; non-conforming programs may or may not
be detected.  If they are detected, the Standard says nothing about
what the error message (if any) must say.

Bill Leonard (member, X3J3)
Harris Computer Systems Division
2101 W. Cypress Creek Road
Fort Lauderdale, FL  33309
bill@ssd.harris.com or bill%ssd.harris.com@eddie.mit.edu