Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!njin!princeton!udel!wuarchive!emory!hubcap!mjs
From: mjs@hubcap.clemson.edu (m j saltzman)
Newsgroups: comp.lang.fortran
Subject: Duplicate names in formal parameter lists
Summary: Should this produce an error?
Message-ID: <11084@hubcap.clemson.edu>
Date: 22 Oct 90 16:49:10 GMT
Distribution: usa
Organization: Clemson University
Lines: 22

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