Path: ...!news.nobody.at!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c Subject: Re: is it possible to have functions with 0, 1, or 2 args? Date: Mon, 12 Aug 2024 02:28:24 -0700 Organization: A noiseless patient Spider Lines: 25 Message-ID: <8634naccp3.fsf@linuxsc.com> References: <7q-dnbTDU4oBES37nZ2dnZfqnPednZ2d@brightview.co.uk> <20240805151946.00000bce@yahoo.com> <86wmkmfhaz.fsf@linuxsc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Date: Mon, 12 Aug 2024 11:28:24 +0200 (CEST) Injection-Info: dont-email.me; posting-host="f42e4005105099d89c60a754521770ce"; logging-data="3404816"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX180Z7v6to1LchC5AHbk8VyZuiGtoyxKgHE=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:42MY2PpJyU8ej18fa9IL4l2bT5E= sha1:8GWyDfPaUfEFuLlkArleFb1l2/o= Bytes: 2163 Richard Harnden writes: > On 12/08/2024 06:20, Tim Rentsch wrote: > >> Michael S writes: >> >>> On Mon, 05 Aug 2024 08:26:04 +0000 >>> Mark Summerfield wrote: >>> >>> According to my understanding, vararg functions without arguments will >>> become possible in C23. But since fully functional C23 compilers do not >>> exist yet, right now the answer to your question is "No". >> >> Even in C99 varargs functions can be called without arguments. >> The question here is more subtle. In fact it is possible even >> in C99 and C11 to do what he wants, but it isn't easy, and it >> is far from obvious how to go about it. Still, if the question >> is "can this be done?", the answer is Yes even now. > > How does va_start know where to, um, start from if there's no last > named argument? Sorry, I meant to say macros, not functions (using ... and __VA_ARGS__). The original question is about macro definitions, not function definitions, and I didn't read carefully enough.