Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!ubiquity
From: ubiquity@cs.utexas.edu (Richard Hoffman)
Newsgroups: comp.lang.fortran
Subject: Re: EQUIVALENCE or STRUCTURE/RECORD ?
Summary: Try COMMON
Message-ID: <16738@cs.utexas.edu>
Date: 10 Jan 91 14:09:49 GMT
References: <6683.278c85d2@cc.curtin.edu.au>
Organization: Ubiquitous Productions, R. Hoffman Proprietor
Lines: 27

In article <6683.278c85d2@cc.curtin.edu.au> Gumley_LE@cc.curtin.edu.au
(Liam Gumley) writes:
>The VAX compiler gives an error at the equivalence line [when you try
>to use EQUIVALENCE with a formal paramter].  Now I know I could
>do the equivalence in the main program and pass 'data' to the subprogram,
>but I would like to do it in the subroutine if I can.  Can I do this using
>structure and record statements, or some other way?

I never have understood why you can't equivalence formal parameters,
but most FORTRAN compilers won't let you.  One workaround is to not
pass buffer formally at all, but use labelled COMMON instead.  For
example:

C Main program
      BYTE BUFFER(100)
      COMMON /X/ BUFFER

C Subroutine
      INTEGER*4 DATA(20)
      COMMON /X/ DATA

This may not be appropriate in all cases.
-- 
Richard Hoffman             IBM Entry Systems Division            (512) 823-1822
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