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From: Gabriel Dos Reis <gdr@integrable-solutions.net>
To: gcc-bugzilla@gcc.gnu.org
Cc: gcc-bugs@gcc.gnu.org
Subject: Re: [Bug c/22485] pointer +- integer is never NULL
Date: Thu, 14 Jul 2005 19:38:00 -0000 [thread overview]
Message-ID: <m3mzopfabq.fsf@uniton.integrable-solutions.net> (raw)
In-Reply-To: <20050714153701.29650.qmail@sourceware.org>
"falk at debian dot org" <gcc-bugzilla@gcc.gnu.org> writes:
| ------- Additional Comments From falk at debian dot org 2005-07-14 15:37 -------
| (In reply to comment #7)
|
| > I'm failing to find anything in the C++ standard that suggests that the
| > following shall be undefined
| >
| > (reinterpret_cast<int*>(0) + 5) - 5
|
| If (reinterpret_cast<int*>(0) + 5) - 5 is not undefined, then neither is
| reinterpret_cast<int*>(0) + 5. Then what is its result, by which paragraph
| in the standard?
The standard says that the mapping used by reinterpret_cast to turn an
integer into a pointer is *implemented-defined*. It is not undefined.
GCC uses the "obvious" mapping, which is reinterpret_cast<int*>(0) is
the null pointer.
-- Gaby
next prev parent reply other threads:[~2005-07-14 19:38 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-14 13:10 [Bug c/22485] New: " mattias at virtutech dot se
2005-07-14 13:14 ` [Bug c/22485] " pinskia at gcc dot gnu dot org
2005-07-14 13:14 ` mattias at virtutech dot se
2005-07-14 13:19 ` falk at debian dot org
2005-07-14 13:45 ` dberlin at gcc dot gnu dot org
2005-07-14 13:46 ` falk at debian dot org
2005-07-14 15:19 ` gdr at integrable-solutions dot net
2005-07-14 15:21 ` gdr at integrable-solutions dot net
2005-07-14 16:03 ` falk at debian dot org
2005-07-14 19:38 ` Gabriel Dos Reis [this message]
2005-07-14 21:47 ` Falk Hueffner
2005-07-14 19:40 ` gdr at integrable-solutions dot net
2005-07-14 22:19 ` falk at debian dot org
2005-07-14 23:04 ` gdr at integrable-solutions dot net
2005-07-15 7:51 ` falk at debian dot org
2005-07-15 8:26 ` gdr at integrable-solutions dot net
2005-07-15 9:27 ` mattias at virtutech dot se
2005-07-15 10:35 ` gdr at integrable-solutions dot net
2005-07-15 11:42 ` pluto at agmk dot net
2005-07-15 14:25 ` falk at debian dot org
2005-07-15 15:02 ` gdr at integrable-solutions dot net
2005-07-15 15:21 ` falk at debian dot org
2005-07-15 15:54 ` mattias at virtutech dot se
2005-09-24 5:37 ` gdr at gcc dot gnu dot org
2005-09-24 9:39 ` falk at debian dot org
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