Re: Knowing the number of variable arguments.

[Alexandre Oliva <aoliva@cygnus.com>]

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On May 29, 2000, Gigi Sullivan <sullivan@sikurezza.org> wrote:

>> On May 29, 2000, Gigi Sullivan <sullivan@sikurezza.org> wrote:

>> > 	This is bad, since I cannot know *when* the list is terminated

>> How about requiring a NULL terminator, as in exec()?

> 	Well, I would avoid using this solution (It's boring for what
> 	I'm doing to put *mandatory* a NULL at the end).

If there's no perfect solution, a boring one will have to do, right? :-)

> 	Nevertheless to say (well, as you know ;)) that this could be
> 	non-portable too (Am I right?) :

Nope.  If you pass a list of pointers, the last of which is NULL, then
you can certainly expect va_arg to work correctly on all platforms, as
long as you tell it each argument is the appropriate pointer type.

> 	Not all pass parameters on the stack (that could grows towards
> 	lower/upper address).

va_arg will take care of this for you.

> Could be this an addendum to the current gcc?

What kind of extension are you thinking of?

-- 
Alexandre Oliva    Enjoy Guaraná, see http://www.ic.unicamp.br/~oliva/
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