X-Spam-Check-By: sourceware.org Date: Fri, 20 Jan 2006 18:48:16 +0200 Message-Id: From: Eli Zaretskii To: Eric Blake CC: cygwin@cygwin.com, henman@it.to-be.co.jp, emacs-devel@gnu.org In-reply-to: <43D0F12A.4000202@byu.net> (message from Eric Blake on Fri, 20 Jan 2006 07:18:18 -0700) Subject: Re: New platform independent problem Reply-to: Eli Zaretskii References: <43D0797C.1030604@it.to-be.co.jp> <43D0F12A.4000202@byu.net> Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk 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 > Date: Fri, 20 Jan 2006 07:18:18 -0700 > From: Eric Blake > CC: cygwin@cygwin.com, henman@it.to-be.co.jp, emacs-devel@gnu.org > > Which is why it is prohibitively expensive for cygwin to populate it with > the correct value on WinNT and Win2K; too few applications use d_ino to > make it worth doing the Windows equivalent of stat during the readdir() to > correctly populate the d_ino member. But if we are going to populate > d_ino, it had better either be st_ino (so we aren't lying), or a sentinel > that makes it obvious that st_ino should be used instead (either 0 or -1). > Fortunately, Win9x and WinXP had non-prohibitive costs to making d_ino > match st_ino. You could have a flag that, if set, will instruct readdir to do the expensive processing. Applications that need the real inode will set that flag. > > What is bad is to have dirent.h, but not some of the struct members it > > calls for. > > POSIX permits implementations to not have d_ino. In other words, when it > comes to dirent.h, cygwin is fully POSIX-compliant to not have a d_ino > member, and applications had better not assume that d_ino exists. That may be so, but I don't think I've seen packages that check whether d_ino exist in their configury. They assume it does, AFAICS. > > It's bad mantra for an application to use a symbol that starts with > > "__", since those symbols are reserved for the library implementation. > > My understanding is that leading __ is reserved for the IMPLEMENTATION in > general, not just the library implementation; cygwin is part of the > implementation. I was responding to a suggestion to use __deprecated_d_ino in the Emacs code. Emacs is certainly _not_ a part of implementation. > What platforms use d_ino==0 to mean an empty entry, rather than an entry > where st_ino must be checked? I see it in Emacs, Corinna shows another example from rcp and scp. -- 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/