From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/6348 Path: news.gmane.org!not-for-mail From: Szabolcs Nagy Newsgroups: gmane.linux.lib.musl.general Subject: Re: Constants to decode __ctype_b_loc() table Date: Thu, 16 Oct 2014 14:21:46 +0200 Message-ID: <20141016122146.GI4874@port70.net> References: <20141015104142.GA2186@zx-spectrum.accesssoftek.com> <20141015113207.GF4874@port70.net> <20141015120531.GA5017@zx-spectrum.accesssoftek.com> <20141015165136.GS32028@brightrain.aerifal.cx> <20141015191946.GB1552@zx-spectrum.accesssoftek.com> <20141016005842.GT32028@brightrain.aerifal.cx> <20141016015333.GG4874@port70.net> <20141016020712.GV32028@brightrain.aerifal.cx> <20141016083739.GA2525@zx-spectrum.accesssoftek.com> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1413462129 25929 80.91.229.3 (16 Oct 2014 12:22:09 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 16 Oct 2014 12:22:09 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-6361-gllmg-musl=m.gmane.org@lists.openwall.com Thu Oct 16 14:22:02 2014 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1Xek46-0002nj-Nk for gllmg-musl@plane.gmane.org; Thu, 16 Oct 2014 14:21:58 +0200 Original-Received: (qmail 15686 invoked by uid 550); 16 Oct 2014 12:21:58 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 15678 invoked from network); 16 Oct 2014 12:21:57 -0000 Mail-Followup-To: musl@lists.openwall.com Content-Disposition: inline In-Reply-To: <20141016083739.GA2525@zx-spectrum.accesssoftek.com> User-Agent: Mutt/1.5.23 (2014-03-12) Xref: news.gmane.org gmane.linux.lib.musl.general:6348 Archived-At: * Sergey Dmitrouk [2014-10-16 11:37:39 +0300]: > On Wed, Oct 15, 2014 at 07:07:12PM -0700, Rich Felker wrote: > > In the link you cited: > > > > "This interface is not in the source standard; it is only in the > > binary standard." > > Even if it's a binary interface, it shouldn't be underspecified. Right > now __ctype_b_loc.c contains an array of numbers which correspond to > what glibc has. Consider the following situation: glibc changes masks > at some point, musl doesn't, someone uses masks from new glibc's > headers after reading a thread like this one and obtains broken locales. either glibc changes its locale system and keeps __ctype_b_loc around with the old semantics (which they can do any time) or they change the semantics of __ctype_b_loc breaking the current abi (which they should not do) this is why depending anything in source headers is broken when you depend on internal abi: internal details of the source can change, there is no guarantee about them, abi that is visible to existing binaries cannot change (hopefully) so libc++ should not use undocumented masks from glibc ctype.h libc++ should use standard interfaces (that should be the default) and if it must use __ctype_b_loc then recognize that glibc headers are not under their control so they have to replicate the bits they care about > Having this documented in form of a comment instead of public interface > would be good as well, in this case clients could consult place where > it's documented and be sure that their constants are correct. Say, add > a comment to __ctype_b_loc.c to clarify meaning of the table and > document masks at the same time. i think adding a comment makes sense, but i think we should not encourage the dependence on accidentally visible abi details of the libc