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From: diamond@csl.sony.co.jp (Norman Diamond)
Newsgroups: comp.lang.c
Subject: Re: pointers to functions
Keywords: pointers, functions, portable
Message-ID: <10779@riks.csl.sony.co.jp>
Date: 1 Sep 89 02:32:10 GMT
References: <1679@hydra.gatech.EDU>
Reply-To: diamond@riks. (Norman Diamond)
Organization: Sony Computer Science Laboratory Inc., Tokyo, Japan
Lines: 27

In article <1679@hydra.gatech.EDU> wj4@prism.gatech.EDU (JOYE,WILLIAM A) writes:

>extern void printf;
>main()
>{
>	void (*f)() = printf;
>	f("Hello, world\n");		/* are these two methods equivalent? */
>	(*f)("Hello, world again\n" );
>}

The two methods are equivalent.  But I have a question:  why does it
work under gcc?

I understand that gcc uses different calling conventions for ordinary
functions and stdargs (varargs) functions.  That is why you cannot
declare a prototype as just "()" without "..." and then define it
with "...".

The definition of f makes (*f) non-stdargs.  But the actual printf
expects stdargs.  So why does it work?!


-- 
Norman Diamond, Sony Corporation (diamond@ws.sony.junet)
  The above opinions are inherited by your machine's init process (pid 1),
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