From: Geoff Keating <geoffk@cygnus.com>
To: "Joseph S. Myers" <jsm28@cam.ac.uk>
Cc: gcc@gcc.gnu.org
Subject: Re: 128-bit integers and intmax_t
Date: Mon, 18 Sep 2000 14:44:00 -0000 [thread overview]
Message-ID: <jm7l89z7s0.fsf@envy.cygnus.com> (raw)
In-Reply-To: <Pine.LNX.4.21.0009182153020.18463-100000@kern.srcf.societies.cam.ac.uk>
"Joseph S. Myers" <jsm28@cam.ac.uk> writes:
> When HOST_BITS_PER_WIDE_INT >= 64, gcc has some support for 128-bit
> integer types (`int __attribute__((__mode__(__TI__)))' and `unsigned int
> __attribute__((__mode__(__TI__)))'). Should these count as "extended
> integer types" (within the meaning of C99 6.2.5p7)?
>
> If they so count, then intmax_t and uintmax_t would need to be defined
> accordingly - which would break existing ABIs (e.g. glibc), and the
> dependence on HOST_BITS_PER_WIDE_INT would be rather undesirable. The
> pragmatic solution seems to be to define that these types are not extended
> integer types, regardless of the level of support GCC has for them and how
> much they look like extended integer types, and to add appropriate
> -pedantic warnings, but does anyone see any better solution?
This is a libc issue. They are extended integer types if and only if
the libc defines intmax_t (or some other standard type) as them.
Otherwise, there's no way for a strictly conforming C program to know
they exist.
--
- Geoffrey Keating <geoffk@cygnus.com>
prev parent reply other threads:[~2000-09-18 14:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-09-18 14:14 Joseph S. Myers
2000-09-18 14:44 ` Geoff Keating [this message]
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