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From: Wolfgang Helbig <helbig@Informatik.BA-Stuttgart.DE>
Message-Id: <199709080907.LAA05238@rvc1.informatik.ba-stuttgart.de>
Subject: Re: 'warning: function declaration isn't a prototype'
In-Reply-To: <19970908002641.TV55800@uriah.heep.sax.de> from J Wunsch at "Sep 8, 97 00:26:41 am"
To: joerg_wunsch@uriah.heep.sax.de
Date: Mon, 8 Sep 1997 11:07:52 +0200 (MET DST)
Cc: hackers@FreeBSD.ORG
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> As Jonathan Mini wrote:
> 
> > ...and I was prototyping. Like this :
> > 
> > static	void		msctimer();
> > 
> > I changed it to :
> > 
> > static	void		msctimer(void);
> > 
> > ... and the problem went away. Funny, I have never received that watning
> > before, and I have been using C (with prototypes like that) for many years.
> 
> That's not a `prototype' in the strict ANSI sense.  Unless we were
> talking about C++, where the omission of function parameters is
> equivalent to declaring the list as just `void'.  But then, C++ always
> requires prototypes, unlike ANSI C.
> 
> What you've been using is what K&R II calls ``old-style function
> declarations''.

Strange thing is, I cannot provoke this warning, i. e this source
compiles with -ansi -pedantic -Wall option without any messages
output by cc(1).  What am I missing?

Wolfgang

The Source(tm):

#include <stdio.h>
static void func();   /* This is not valid  */
static void func2(void);

void
main (void)
{
	printf("Hello, world\n");
	func();
	func2();
}

static void
func()
{
	printf("Dies ist func()\n");
}

static void
func2()
{
	printf("Dies ist func2()\n");
}