X-Spam-Check-By: sourceware.org From: "Dave Korn" To: References: <1cbe225f0704160234u24b104a5o9b459178e895a5a8@mail.gmail.com> Subject: RE: C++ name with leading underscore character not Compiling Date: Mon, 16 Apr 2007 10:41:08 +0100 Message-ID: <018901c7800b$5c4ec450$2e08a8c0@CAM.ARTIMI.COM> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 11 In-Reply-To: <1cbe225f0704160234u24b104a5o9b459178e895a5a8@mail.gmail.com> Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com On 16 April 2007 10:34, Chelton Evans wrote: > I believe it is legal to have a C++ variable name with a leading > underscore. No. All names beginning with an underscore are reserved for the implementation. However, the compiler allows it, because for all it knows your code could be part of the OS or libc that has the legitimate right to use such identifiers. But technically it's actually undefined behaviour, the reason being that you may tread on a reserved name. > A name with two underscores is reserved, so > I guess this is illegal. Currently the two cases are reversed. > class hat { ... void fred( int __name) ... compiles, but > class hat { ... void fred( int _name)... which is legal does not > compile. > > Could you confirm or deny the problem. I deny it: /artimi $ cat t.cpp class hat { void fred( int _name); void fred2( int __name); }; /artimi $ g++ -c t.cpp -o t.o -W -Wall /artimi $ cheers, DaveK -- Can't think of a witty .sigline today.... -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/