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From: charlie@mica.stat.washington.edu (Charlie Geyer)
Newsgroups: comp.lang.fortran
Subject: Re: DO loops, anyone?
Message-ID: <1311@uw-entropy.ms.washington.edu>
Date: 12 Mar 89 01:49:13 GMT
References: <458@orange19.qtp.ufl.edu>
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Reply-To: charlie@mica.stat.washington.edu (Charlie Geyer)
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In article <458@orange19.qtp.ufl.edu> bernhold@qtp.ufl.edu 
(David E. Bernholdt) writes:
 
>      PROGRAM LOOP
>      IGO = 1
>      DO 501 I = 1, 10
>         WRITE (6,*) 'OUTER LOOP, I =',I
>         IF (IGO .NE. 0) GOTO 501
>         DO 501 J = 1, 5
>            WRITE (6,*) 'INNER LOOP, J=',J
> 501     CONTINUE
>         STOP
>         END
>
> 1) Is the code standard-conforming?  I think it is, but perhaps I am
> mistaken.

No.  Statement 501 is in the range of the inner DO loop.  So the GOTO
branches into the range of an inactive loop.  This is not allowed.

There was a very long discussion about this about a month ago.

Some compilers are friendlier about this than others.  Two compilers
here execute the code the way you expect.  But there is no "correct"
way to execute this code.