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From: przemek@gondor.psu.edu (Przemyslaw Klosowski)
Newsgroups: comp.lang.fortran
Subject: Re: FORTRAN value passed parameters revisited
Message-ID: <3005@psuvax1.psu.edu>
Date: Fri, 16-Oct-87 12:57:26 EDT
Article-I.D.: psuvax1.3005
Posted: Fri Oct 16 12:57:26 1987
Date-Received: Sat, 17-Oct-87 20:57:32 EDT
References: <5359@jade.BERKELEY.EDU> <2702@xanth.UUCP>
Sender: netnews@psuvax1.psu.edu
Reply-To: przemek@gondor.psu.edu (Przemyslaw Klosowski)
Organization: Penn State University, University Park, PA
Lines: 31
Keywords: Value passed, f77

In article <5359@jade.BERKELEY.EDU> lagache@violet.berkeley.edu (Edouard Lagache) writes:
>
>    A few days ago I pointed out a dirty trick that ought to make
>    if possible to have the effect of value passed parameters in FORTRAN.
>[...]but I also recieved
>    a message that it doesn't work under some cases.  Apparantly, the f77
>    compiler "sees" through the 'X+0' trick and makes X a variable pass
>    parameter.

Several people pointed that optimizing compilers do see thru that, and
call foo((x+0)) compiles to the same thing as call foo(x).
Let me point however that if you want to avoid the ``variable'' problem,
you are probably safe with
	dummy=x
	call foo(dummy)
which is (to me) cleaner.
REMINDER: there is always this proverbial bug when you do:
	call foo(5)
	print(*,*)5
	....
	subroutine foo(n)
	n=6
	end
and you get ``6'' printed out!

			przemek



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