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From: Keith Thompson <ks...@mib.org>
Newsgroups: comp.lang.c,de.comp.lang.c,comp.std.c,comp.lang.fortran
Subject: Re: standard pragma's II
Date: Fri, 29 Oct 2010 09:36:15 -0700
Organization: None to speak of
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Keith Thompson <ks...@mib.org> writes:
> Dick Hendrickson <dick.hendrick...@att.net> writes:
> [snip]
[...]
>>         subroutine silly (a,b)
>>         a = a/27.0
>>         b = 1.0
>>         end
[...]
> The C equivalent of the above would have to use pointers, since
> all arguments are passed by value:
>
>     void silly(double *a, double *b) {
>         a /= 27.0;
>         b = 1.0;
>     }

Whoops, I forgot to dereference the pointer parameters.  That should be:

    void silly(double *a, double *b) {
        *a /= 27.0;
        *b = 1.0;
    }

 *think* that the "restrict" qualifier would give the compiler
> the same freedom a Fortran compiler would have:
>
>     void silly(double *restrict a, double *restrict b) {
>         a /= 27.0;
>         b = 1.0;
>     }

And likewise.

> But I don't claim to understand "restrict" fully, so I'm not certain
> of this.

See also James Kuyper's followup.

-- 
Keith Thompson (The_Other_Keith) ks...@mib.org  <http://www.ghoti.net/~kst>
Nokia
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"