Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!tut.cis.ohio-state.edu!att!dptg!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c
Subject: Re: prototype my function, please...
Keywords: prototype
Message-ID: <10848@alice.UUCP>
Date: 21 May 90 21:43:10 GMT
References: <1231@wet.UUCP>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 49

In article <1231@wet.UUCP>, noah@wet.UUCP (Noah Spurrier) writes:

> I get the bad feeling that I am going to get flamed for this... But I can
> see no reason why my Turbo C compiler does not like the way I prototype
> the following program.

> /* Protoypte */
> void x (float);

	/* ... */

> void x (y)
> float y;
> {
>  printf ("%f",y);
> }

You should do it this way:

	void x(float y)
	{
		printf("%f",y);
	}

The point is that old-style parameter declarations are decidedly
not equivalent to new-style declarations.  For compatibility reasons,
it must be legal to define

	void x(y)
		float y;
	{
		/* ... */
	}

and call it from a separately compiled module without any declaration
there at all.  That means it must be capable of accepting a double
parameter.  Thus, in effect, this least example is equivalent to:

	void x(double dummy)
	{
		float y = dummy;
		/* ... */
	}

In other words, if you want to use ANSI-style function prototypes,
you must use them consistently.
-- 
				--Andrew Koenig
				  ark@europa.att.com