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Re: CVS commit: src
On Thu, Sep 01, 2011 at 08:19:07AM +0100, Iain Hibbert wrote:
> On Wed, 31 Aug 2011, Warner Losh wrote:
> > In the absence of both the prototype and a cast, NULL (which can be 0)
> > will be passed as an int, not as a pointer.
> NetBSD C headers define NULL as ((void *)0), and our Makefiles use -Wall
> (includes -Wimplicit-function-declaration) to avoid such situations..
ISTR that ansi C (or some recent version of it) does require that
NULL be a pointer constant - so that it gets passed correctly to
varargs functions that expect a data pointer.
Without function prototypes this is a bigger problem, especially
since (char *)0 isn't a useful definition!
This is where 'lint' comes in handy, since it (effectively) checked
that args matched the inferred prototype ...
David Laight: david%l8s.co.uk@localhost
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