Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!uwm.edu!ux1.cso.uiuc.edu!pluto!hirchert
From: hirchert@pluto.ncsa.uiuc.edu (Kurt Hirchert)
Newsgroups: comp.lang.fortran
Subject: Re: Duplicate names in formal parameter lists
Message-ID: <1990Oct22.202712.29478@ux1.cso.uiuc.edu>
Date: 22 Oct 90 20:27:12 GMT
References: <11084@hubcap.clemson.edu>
Sender: news@ux1.cso.uiuc.edu (News)
Reply-To: hirchert@pluto.ncsa.uiuc.edu (Kurt Hirchert)
Distribution: usa
Organization: National Center for Supercomputing Applications
Lines: 31

In article <11084@hubcap.clemson.edu> mjs@hubcap.clemson.edu (m j saltzman) writes:
>I discovered an error in a FORTRAN program I was modifying, which amounts
>to the following:
>
>	SUBROUTINE FOO(X, [other parameters], X)
>	DOUBLE PRECISION X(N)
>
>	[rest of code]
>
>This compiled without error on a Sun (with the -u flag) and on ULTRICS.
>Fortunately (?), the calling routine supplied the same argument in both
>positions, so no error occurred during execution.
>
>Questions: Is this really legal FORTRAN 77?  If so, is it useful for
>anything?  What are the semantics of a call to the routine with different
>arguments, say FOO(Y, ..., Z)?  If not, why don't common compilers
>(at least these) detect the error?  Other types of duplicate declarations
>are detected.	
>
>Thanks for any insight.
>
>		Matthew Saltzman
>		mjs@clemson.edu

This is _not_ legal FORTRAN 77.  Since compilers on rather unlike machines
failed to complain about it, I assume some vendor must have created a useful
extension using that syntax and that other vendors then copied it.  I have
no idea what that extension might actually do.
--
Kurt W. Hirchert     hirchert@ncsa.uiuc.edu
National Center for Supercomputing Applications