Message-ID:	<394E66A7.C74BEB0C@softhome.net>
Date:	Mon, 19 Jun 2000 20:29:59 +0200
From:	Laurynas Biveinis <lauras AT softhome DOT net>
X-Mailer:	Mozilla 4.73 [en] (Win98; U)
X-Accept-Language:	lt,en
MIME-Version:	1.0
To:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
CC:	DJGPP Workers <djgpp-workers AT delorie DOT com>
Subject:	Re: Patch: new GCC builtins for stdarg.h/varargs.h
References:	<Pine DOT SUN DOT 3 DOT 91 DOT 1000619200929 DOT 28843A-100000 AT is>
Reply-To:	djgpp-workers AT delorie DOT com

Eli Zaretskii wrote:
> It is true that va_copy is supported by GCC builtins in
> 2.96 only, is it?

Yes.

> > Currently there's nothing wrong. But when we start adding C99
> > features, it will become wrong.
> 
> What will become wrong?

It will be a missing C99 feature.

> We don't intend to support C99 features that require compiler support,
> unless the version of the compiler in use actually does provide that
> support, do we?

But compiler support here is optional, like with va_arg etc.

> Since va_copy requires a special feature of the compiler, we can require
> that the compiler be new enough, for va_copy to be supported.  People who
> use older compilers won't have va_copy, just like they don't today.

That's true if builtins are the only way to implement va_copy. But
DJGPP with va_arg etc. already has proved that other implementations
are possible.

> The point is that introducing a new feature without compiler support is
> different from continued support for an old feature that is proven to
> work with old compilers.

And what about introducing a new feature which works with both old and
new compiler? Just like we have two cases for va_list now, with and
without builtins?

Laurynas

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