Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!cmcl2!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: gcc bug (possibly)
Message-ID: <9786@smoke.BRL.MIL>
Date: 5 Mar 89 00:56:30 GMT
References: <9201@orstcs.CS.ORST.EDU>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 17

In article <9201@orstcs.CS.ORST.EDU> budd@mist.cs.orst.edu (Tim Budd) writes:
>Unless I am seriously mistaken in my understanding of prototypes, our version 
>of gcc produces an error in what I believe is a correct program.  
>extern int foo ( short );
>int foo(x)
>short x;
>{ ; }
>I get a message that the argument doesn't match the prototype.

GCC is correct to complain about this usage.

That's because the parameter (formal argument) doesn't match the
prototype.  By using an old-style function definition, you've
required that `x' be passed as an int, then converted to short
upon entry to the function.  The prototype says that it's passed
as a short in the first place.  Those two functions interfaces
are not in general conformable.