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From: Willem <willem@toad.stack.nl>
Newsgroups: comp.lang.c
Subject: Re: is there anything unstandard in the c part here
Date: Thu, 28 Jul 2011 07:58:04 +0000 (UTC)
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.c:8798

Ike Naar wrote:
) To be fair, the preferred idiom also relies on duplication: in
)
)     p = malloc(n * sizeof *p);
)
) the duplication is benign, but if the pointer expression
) becomes more complicated, as in
)
)     *(*co_matrix)[pivot] = malloc(n * sizeof **(*co_matrix)[pivot]);
)
) the duplication becomes a bit of a nuisance.
) Because of the duplicated complexity, a silly mistake like
)
)     *(*co_matrix)[pivot] = malloc(n * sizeof *(*co_matrix)[pivot]);
)
) may creep in, which is not caught by the compiler, and is easily
) overlooked during code inspection.
)
) Also, if the pointer expression has side effects:
)
)     a[j++] = malloc(n * sizeof *a[j++]);
)
) although the preferred idiom works okay here (thanks to the fact that
) sizeof does not evaluate its operand), this may confuse the reader.

Which is why god invented macros.

#define NEW(x,n) ((x)=malloc((n) * sizeof(x)))

(If I remember correctly)


SaSW, Willem
-- 
Disclaimer: I am in no way responsible for any of the statements
            made in the above text. For all I know I might be
            drugged or something..
            No I'm not paranoid. You all think I'm paranoid, don't you !
#EOT