Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: void * compatibility
Message-ID: <1990Sep23.002428.16099@zoo.toronto.edu>
Organization: U of Toronto Zoology
References: <8770@b11.ingr.com> <26628@mimsy.umd.edu>
Date: Sun, 23 Sep 90 00:24:28 GMT

In article <26628@mimsy.umd.edu> chris@mimsy.umd.edu (Chris Torek) writes:
>Personally, I think defining NULL as (void *)0 is foolishness: if you
>want your compiler to provide complete error checking, you should define
>it as `__nil' and make __nil a keyword.  Using (void *)0 fixes a few
>specific problems, but leaves others unfixed and unfixable.

Actually, the Rationale for ANSI C makes it clear that error checking had
nothing to do with making `(void *)0' an official null pointer.  The
motive was to provide for a NULL of the same size as most pointers --
thereby minimizing breakage of old defective code -- on machines where
there is no integer type of the right size.  Minimizing breakage is also
the reason why (e.g.) `0L' is also a legal NULL, for machines where
pointers are the size of longs rather than ints.
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