Path: utzoo!attcan!uunet!cs.utexas.edu!yale!cmcl2!lanl!lambda!cox
From: cox@lanl.gov (Robert W. Cox)
Newsgroups: comp.lang.fortran
Subject: Re: implicit none
Message-ID: <14457@lambda.UUCP>
Date: 3 Aug 90 14:11:27 GMT
Sender: news@lambda.UUCP
Lines: 21

From article <26B8B79D.15026@ics.uci.edu>, by levine@crimee.ics.uci.edu (David Levine):
> I prefer the command line option, if available.  No code changes
> are required if you ever have to port to a compiler that doesn't
> support IMPLICIT NONE.

 Not always (unfortunately)!  Not all compilers are perfect, by any means.
 I've used a FORTRAN compiler that produced incorrect object code if you
 explicitly declared a variable to be its default type, such as

    REAL X
    INTEGER I

 As you can imagine, this is annoying and hard to discover.  And makes
 converting from IMPLICIT NONE annoying as well.  Not that I don't
 advocate IMPLICIT NONE -- when someone comes to me with a code that
 doesn't work, the first thing I tell them to do is to declare all
 variables and try again.  This has one advantage:  they go away for
 a while, and it sometimes even fixes their program!

Bob Cox
cox@lanl.gov