From: Arnd Bergmann <arnd@arndb.de>
To: Roland McGrath <roland@redhat.com>
Subject: Re: [RFC] asm-generic/{unistd,types,posix_types}.h for new arch
Date: Thu, 2 Apr 2009 15:06:12 +0200
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On Wednesday 01 April 2009, Roland McGrath wrote:
> > Actually, gcc does have the _LP64 and __SIZEOF_POINTER__ macros (as well 
> > as __CHAR_BIT__), although I don't know how far back it does have that. 
> > ? ? ?If it has been with us for long enough it might be possible to 
> > switch over to using panarch macros.

For user space, we also need to consider non-gcc compilers that could have
a different set of macros. As long as we don't start relying on any new
ones besides those we already use (__x86_64__, __s390x__, __powerpc64__,
__mips64, __arch64__), we at least don't break anything accidentally.

> Worst case the oldest compilers had <limits.h> and 
> "#if ULONG_MAX == 0xffffffffUL", though I wouldn't like
> myself to be using a setup where <limits.h> got pulled in.

That would of course work with non-gcc, but we are really not allowed
to pull in <limits.h> from places like <types.h> where it would be needed
then.

	Arnd <><
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