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From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.std.c
Subject: Re: prototypes required ?
Keywords: printf stdargs prototypes
Message-ID: <14182@smoke.BRL.MIL>
Date: 18 Oct 90 16:48:04 GMT
References: <4026@otis.oakhill.UUCP> <14164@smoke.BRL.MIL> <1964@ccadfa.adfa.oz.au>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 12

In article <1964@ccadfa.adfa.oz.au> Christopher-Vance@adfa.oz.au writes:
>gwyn@smoke.BRL.MIL (Doug Gwyn) writes:
>| Yes, you definitely must have a prototype in scope before calling a
>| variable-argument function in a strictly conforming program.
>Which means that gcc -ansi on a Pyramid cannot compile such a thing. I am
>informed that the only way to make printf work is to *omit* the prototype.

As I said before, you should rely on <stdio.h> to properly declare printf().
If <stdio.h> is not included at all, then the C standard guarantees that you
could declare printf() directly in your program, providing that you use the
prototype specified in the standard.  "extern int printf();" on the other
hand has undefined behavior.