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Date: Mon, 28 Jan 2002 20:51:00 -0000
From: Andrew Cagney <ac131313@cygnus.com>
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To: Eli Zaretskii <eliz@is.elta.co.il>
Cc: fnasser@redhat.com, gdb-patches@sources.redhat.com
Subject: Re: [rfa/cli] s/NO_FUNCTION/NULL/
References: <Pine.SUN.3.91.1020121114951.16755I-100000@is> <3C4C46E8.F48A93D7@redhat.com> <3C4C5FC4.6030609@cygnus.com> <2561-Tue22Jan2002105639+0200-eliz@is.elta.co.il>
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> Date: Mon, 21 Jan 2002 13:36:52 -0500
>> From: Andrew Cagney <ac131313@cygnus.com>
>> 
>> My ISO C is pretty rusty, however my memory is that NULL is very very 
>> special.
> 
> 
> In C++, but not in C, IIRC.
> 
> 
>> GDB built with GCC 3.0.3.  Using current GCC things died mysteriously 
>> part way through the build.
> 
> 
> Well, until GCC 3.1 can compile the whole thing, I guess we don't
> have to worry.


I went and asked.  The following is of course third hand:

In C++, NULL can't be ``(void*)0''.  It should be ``0'' but GCC likes to 
define it to ``__null''.  The latter is a special constant with magic 
properties that lets GCC verify that NULL is being used correctly.

In C, NULL is typically ``(void*)0''.  What ever it is, it must be 
compatible with both data and code pointers.

I think this makes using NULL more robust than NO_FUNCTION?

Andrew