From: Rob Landley <rob@landley.net>
To: musl@lists.openwall.com
Cc: musl@lists.openwall.com, Luca Barbato <lu_zero@gentoo.org>,
basile@opensource.dyc.edu
Subject: Re: NULL
Date: Fri, 11 Jan 2013 23:56:02 -0600 [thread overview]
Message-ID: <1357970162.32505.3@driftwood> (raw)
In-Reply-To: <50ED4E45.6050801@barfooze.de> (from maillist-musl@barfooze.de on Wed Jan 9 05:02:29 2013)
On 01/09/2013 05:02:29 AM, John Spencer wrote:
> glibc defines NULL as __null: a magic variable supplied by GCC and
> compatibles which always has pointer context.
>
> musl defines NULL to 0 in C++.
> this is correct per the standard, but breaks a lot of software on
> 64bit archs,
> because it promotes to int.
The C99 standard section 7.17 defines the NULL macro as:
expands to an implementation-defined null pointer constant
Which means it has pointer type. So either we can typecast it to void
*, or we can rely on the LP64 standard (Linux, FreeBSD, and macosX all
support) which says that long and pointer are always the same size on
both 32 bit and 64 bit, so trivial fix would be #define NULL to (0L)
http://www.unix.org/whitepapers/64bit.html
Rob
next prev parent reply other threads:[~2013-01-12 5:56 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-09 11:02 NULL John Spencer
2013-01-09 12:18 ` NULL Szabolcs Nagy
2013-01-09 13:36 ` NULL John Spencer
2013-01-12 6:32 ` NULL Rob Landley
2013-01-12 6:46 ` NULL Rich Felker
2013-01-12 7:15 ` NULL Luca Barbato
2013-01-12 13:33 ` NULL Rich Felker
2013-01-12 11:39 ` NULL Jens Staal
2013-01-09 13:09 ` NULL croco
2013-01-09 13:47 ` NULL John Spencer
2013-01-09 14:49 ` NULL croco
2013-01-09 14:42 ` NULL Luca Barbato
2013-01-09 14:47 ` NULL Rich Felker
2013-01-09 15:03 ` NULL Luca Barbato
2013-01-09 15:18 ` NULL John Spencer
2013-01-09 15:36 ` NULL Rich Felker
2013-01-09 21:11 ` NULL Rob
2013-01-09 21:53 ` NULL Szabolcs Nagy
2013-01-09 22:17 ` NULL Rob
2013-01-09 23:42 ` NULL Szabolcs Nagy
2013-01-12 6:56 ` NULL Rob Landley
2013-01-12 7:07 ` NULL Bobby Bingham
2013-01-12 13:31 ` NULL Rich Felker
2013-01-13 14:29 ` NULL Rob Landley
2013-01-13 14:56 ` NULL Luca Barbato
2013-01-13 16:29 ` NULL Rob Landley
2013-01-13 17:14 ` NULL Luca Barbato
2013-01-13 15:23 ` NULL Strake
2013-01-13 17:17 ` NULL Luca Barbato
2013-01-13 17:47 ` NULL Szabolcs Nagy
2013-01-13 19:46 ` NULL Rob Landley
2013-01-14 6:11 ` NULL Rich Felker
2013-01-14 8:45 ` musl as a framework to test applications' compatibility with POSIX (was: NULL) Vasily Kulikov
2013-01-14 14:03 ` Rich Felker
2013-01-14 14:30 ` Vasily Kulikov
2013-01-14 15:02 ` Szabolcs Nagy
2013-01-14 15:14 ` Rich Felker
2013-01-14 13:19 ` NULL Rob Landley
2013-01-12 5:56 ` Rob Landley [this message]
2013-01-12 6:42 ` NULL Rich Felker
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