From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25956 invoked by alias); 12 Aug 2002 18:37:15 -0000 Mailing-List: contact gcc-help-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-help-owner@gcc.gnu.org Received: (qmail 25946 invoked from network); 12 Aug 2002 18:37:12 -0000 Received: from unknown (HELO gadolinium.btinternet.com) (194.73.73.111) by sources.redhat.com with SMTP; 12 Aug 2002 18:37:12 -0000 Received: from host217-35-38-41.in-addr.btopenworld.com ([217.35.38.41] helo=sknet01) by gadolinium.btinternet.com with smtp (Exim 3.22 #8) id 17eK3z-0000ur-00; Mon, 12 Aug 2002 19:37:11 +0100 Message-ID: <000b01c2422f$4abe5940$c700a8c0@sknet01> From: "Terry Flannery" To: "Jeffrey C Knupp" , References: Subject: Re: cpp Date: Mon, 12 Aug 2002 11:37:00 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-SW-Source: 2002-08/txt/msg00095.txt.bz2 Have a look at the -Wundef flag Terry ----- Original Message ----- From: "Jeffrey C Knupp" To: Sent: Monday, August 12, 2002 7:13 PM Subject: cpp > To whoever sees this, > I'm a student at Carnegie Mellon University and I've been using the > preprocessor, cpp, from gcc-3.1. I was wondering if and why when a previously undefined > identifier in an #if is used, there is no warning given. For example, if > the first line of my program is "#if Y" and Y has not been defined, it > will not execute the code (obviously), but it also won't tell me that the > identifier wasn't defined. I was wondering if this was done for a reason. > Hopefully, someone can give me an answer. > > Thanks, > Jeff Knupp > Carnegie Mellon University >