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Re: __alignof__(void)
- To: egcs at cygnus dot com, nathan at acm dot org
- Subject: Re: __alignof__(void)
- From: mrs at wrs dot com (Mike Stump)
- Date: Wed, 9 Sep 1998 17:07:32 -0700
> Date: Tue, 08 Sep 1998 17:46:02 +0100
> From: Nathan Sidwell <nathan@acm.org>
> To: egcs@cygnus.com
> What is a desirable value for __alignof__(void) to return?
> IMHO a useful value to return would be the maximum alignment for any
> type.
There are three possibilities, 0, 1, or the above. The above is
really many different values, the maximum alignment of any ANSI C
named type, any regular GNU named type, any possibly named type, and
the maximum alignment permitted by the executable format. The last is
subject to change overtime, and hence, isn't a good value for any
portable program to ever see or know. Also, do you count types like
int __attribute__((__mode__(__OI__))), even though the don't have
names and are poorly supported and can't be aligned by the object file
format?
I distinctly don't like the last possibility. 0 or 1 is fine. 1 is
surprising generally, but if you buy into sizeof(void)==1, then it is
less so.