From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13319 invoked by alias); 7 Jul 2005 04:39:45 -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 13309 invoked by uid 22791); 7 Jul 2005 04:39:41 -0000 Received: from sccrmhc12.comcast.net (HELO sccrmhc12.comcast.net) (204.127.202.56) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Thu, 07 Jul 2005 04:39:41 +0000 Received: from [192.168.1.100] (c-67-182-220-146.hsd1.ut.comcast.net[67.182.220.146]) by comcast.net (sccrmhc12) with ESMTP id <20050707043939012009pnfae>; Thu, 7 Jul 2005 04:39:40 +0000 Message-ID: <42CCB23C.4080108@kangaroologic.com> Date: Thu, 07 Jul 2005 04:39:00 -0000 From: Jonathan Turkanis User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.1) Gecko/20040707 MIME-Version: 1.0 To: gcc-help@gcc.gnu.org Subject: Re: What is the purpose of 'warning: no newline at end of file'? References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2005-07/txt/msg00063.txt.bz2 [Sorry Neo, I think I sent you personal email accidentally] Neo Anderson wrote: > So, what is the purpose of this warning? What possible 'damages' does this warning protect against? I believe this language was added to the standard because at the time some systems were not able to handle files properly if they didn't end in a newline. This wording made it possible to provide conforming C++ implementations for those platforms. I'm not sure if there still are any such systems, but because the standard has given implementations to freedom to do whatever they want (that's what undefined behavior means) if you tell them to process a file not ending in a newline, be warned that if you try to compile your code on another system, the compiler may refuse. I know, for example, that Comeau in strict mode won't compile it. For that matter, neither will gcc with -pedantic-errors. Jonathan > And, what is the 'the behavior'? > > ----Original Message Follows---- > From: Jonathan Turkanis > To: gcc-help@gcc.gnu.org > Subject: Re: What is the purpose of 'warning: no newline at end of file'? > Date: Wed, 06 Jul 2005 21:41:20 -0600 > > Neo Anderson wrote: > >> I don't even think it's a problem. Why do I need (or better have) a line ending? > > > > The C++ standard says: If a source file that is not empty does not end in a newline character, or ends in a newline character immediately preceded by a backslash character, the behavior is undefined. (2.1/1) > > Jonathan > > > >