Re: [PATCH] Use NULL instead of integer 0 in security/selinux/

[Alexandre Oliva <aoliva@redhat.com>]

On Jul 13, 2004, Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> On Sun, 11 Jul 2004, Olaf Titz wrote:
>> in C. (Worse in C++ where usage of NULL is discouraged, I've always
>> wondered about the reasons.)

> [ wondered about this as well, but the answer has been posted before in this
>   thread ]

> Because C++ doesn't do implicit conversions from void * to anything *.

So what?  NULL must have an integral type in C++.  void* is explicitly
forbidding in the C++ Standard.

I don't see that NULL is discouraged in C++.  It's mostly redundant,
like it is in C, and it's not safe for varargs even on machines where
NULL pointers are represented can be zero-initialized, because
pointers to members and regular pointers don't even have the same
size, unlike C, that doesn't have pointers to members and thus can
safely use (intptr_t)0 for NULL and it will even work for varargs
(given the considerations above).

-- 
Alexandre Oliva             http://www.ic.unicamp.br/~oliva/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}