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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Ian Lance Taylor <ian@airs.com>
Cc: "Alex J. Dam" <alexjdam@gmail.com>,
	GCC-Help <gcc-help@gcc.gnu.org>,
	ernesto@ornl.gov
Subject: Re: Moving to AMD64 bit and porting issues
Date: Fri, 04 Nov 2005 11:54:00 -0000	[thread overview]
Message-ID: <61a69f794d1144ba9db3959d2f043afb@kernel.crashing.org> (raw)
In-Reply-To: <m3wtk23fiq.fsf@gossamer.airs.com>

> 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

  reply	other threads:[~2005-11-04 11:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-22  5:26 Ernest L. Williams Jr.
2005-10-24 10:24 ` Alex J. Dam
2005-10-24 10:33   ` random
2005-10-24 10:37   ` Ernest L. Williams Jr.
2005-10-24 19:02     ` Ian Lance Taylor
2005-11-04 11:54       ` Segher Boessenkool [this message]
2005-11-04 12:05         ` Ernest L. Williams Jr.
2005-11-04 12:35           ` Segher Boessenkool

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