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Cc: "Alex J. Dam" <alexjdam@gmail.com>, GCC-Help <gcc-help@gcc.gnu.org>,
        ernesto@ornl.gov
From: Segher Boessenkool <segher@kernel.crashing.org>
Subject: Re: Moving to AMD64 bit and porting issues
Date: Fri, 04 Nov 2005 11:54:00 -0000
To: Ian Lance Taylor <ian@airs.com>
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> You can reliably use 0 as a null pointer constant with one exception.
> When calling a varargs function which expects a pointer as an unnamed
> argument, and when pointers are 64-bits but int is 32-bits, then you
> must either use NULL or you must cast 0 to a pointer type.

Using NULL in this case is not portable; you *must*
use a cast to the exact pointer type that the
varargs function expects to see.  Different pointer
types can have different representation.


Segher