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Re: [Gnu-arch-users] posible issue on ia64 with va_args.
From: |
Andrew Suffield |
Subject: |
Re: [Gnu-arch-users] posible issue on ia64 with va_args. |
Date: |
Wed, 10 Mar 2004 10:28:48 +0000 |
User-agent: |
Mutt/1.5.5.1+cvs20040105i |
On Sat, Mar 06, 2004 at 06:35:43PM +1100, Robert Collins wrote:
> I've found a problem with gcc 3.0.4 (and possibly newer versions)with
> the use of '0' to terminate the arch_call_cmd var_args.
>
> the problem is with promotion:
> u_char * is not promoted at all according to my va_arg info pages. But
> '0' is being promoted incorrectly, and when accessed by va_arg(ap, char
> *) results in a 0x60000000000 value. (I think I have the right number of
> 0's there) :}.
>
> Passing 0L as the terminator, or (t_uchar *)0, or NULL works.
Passing an integer in a stdarg list that will be extracted as a
pointer? Yeah, that's wrong, use NULL, that's what it's for. At call
time the compiler doesn't know that it's necessary to promote the
integer to a pointer - there's no signature.
With the notable exception of printf/scanf/strftime (which are
special-cased in any decent compiler), type matching in stdargs lists
is the problem of the programmer and must be handled carefully. That's
why stdarg isn't very useful.
--
.''`. ** Debian GNU/Linux ** | Andrew Suffield
: :' : http://www.debian.org/ |
`. `' |
`- -><- |
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- [Gnu-arch-users] posible issue on ia64 with va_args., Robert Collins, 2004/03/10
- Re: [Gnu-arch-users] posible issue on ia64 with va_args., Tom Lord, 2004/03/11
- [Gnu-arch-users] Re: posible issue on ia64 with va_args., Miles Bader, 2004/03/11
- Re: [Gnu-arch-users] posible issue on ia64 with va_args.,
Andrew Suffield <=
- Re: [Gnu-arch-users] posible issue on ia64 with va_args., Jan Hudec, 2004/03/11
- [Gnu-arch-users] Re: posible issue on ia64 with va_args., Miles Bader, 2004/03/12
- [Gnu-arch-users] Re: posible issue on ia64 with va_args., Jan Hudec, 2004/03/12
- [Gnu-arch-users] Re: posible issue on ia64 with va_args., Miles Bader, 2004/03/12
- Re: [Gnu-arch-users] Re: posible issue on ia64 with va_args., Andrew Suffield, 2004/03/16
- [Gnu-arch-users] Re: posible issue on ia64 with va_args., Stefan Monnier, 2004/03/16
- Re: [Gnu-arch-users] Re: posible issue on ia64 with va_args., Andrew Suffield, 2004/03/18
- Re: [Gnu-arch-users] Re: posible issue on ia64 with va_args., Jan Hudec, 2004/03/18