Message-ID: <0c2401c30751$05203c90$0600000a@broadpark.no>
From: "Gisle Vanem" <giva AT bgnett DOT no>
To: <djgpp AT delorie DOT com>
References: <0ab801c306bf$4dacb430$0600000a AT broadpark DOT no> <3EA26C19 DOT 81D82449 AT acm DOT org>
Subject: Re: __builtin_va_list bug?
Date: Sun, 20 Apr 2003 17:25:05 +0200
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Reply-To: djgpp AT delorie DOT com

"Eric Sosman" <esosman AT acm DOT org> said:

> > #include <stdarg.h>
> > char x;
> > void foo (va_list arg)
> 
>     Hold on; stop right there.  You've included <stdarg.h>, but you're
> using the argument list declaration from the pre-Standard <varargs.h>
> (or <vararg.h> with some compilers).  The two are not the same, they
> are not interchangeable, and they are *definitely* not miscible.

You mean using "va_list" is pre-standard? (it's used in <stadarg.h>) 
That's funny since djgpp uses it all the time. Have a look at e.g. 
src\libc\ansi\stdio\doprnt.c.

> >   x = va_arg (arg, char);
> 
>     This will be wrong with either <stdarg.h> or <varargs.h>, since
> the actual type of the parameter is not `char' but whatever `char'
> gets promoted to: `int' on most machines, but perhaps `unsigned int'
> on some oddball architectures.  You must specify the promoted type,
> not the type to which you will later "demote" it.

Yes, I know. I use "x = (char) va_arg(arg,int)" to stop gcc complaining.
But my question is why the "int $5" is generated. I guess it's meant to
generated some trap on some system. But neither djgpp nor MingW
have a int 5 handler.

--gv