From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/6701 Path: news.gmane.org!not-for-mail From: =?ISO-8859-1?Q?J=F6rg?= Krause Newsgroups: gmane.linux.lib.musl.general Subject: Re: pthread_equal Date: Mon, 08 Dec 2014 22:11:49 +0100 Message-ID: <1418073109.2353.10.camel@posteo.de> References: <1418049745.15892.10.camel@posteo.de> <20141208145604.GC4574@brightrain.aerifal.cx> <1418055521.15892.16.camel@posteo.de> <20141208162509.GI4574@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1418073128 22659 80.91.229.3 (8 Dec 2014 21:12:08 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 8 Dec 2014 21:12:08 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-6714-gllmg-musl=m.gmane.org@lists.openwall.com Mon Dec 08 22:12:03 2014 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1Xy5b9-0004aG-6F for gllmg-musl@m.gmane.org; Mon, 08 Dec 2014 22:12:03 +0100 Original-Received: (qmail 12215 invoked by uid 550); 8 Dec 2014 21:12:02 -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 12204 invoked from network); 8 Dec 2014 21:12:01 -0000 In-Reply-To: <20141208162509.GI4574@brightrain.aerifal.cx> X-Mailer: Evolution 3.12.8 Xref: news.gmane.org gmane.linux.lib.musl.general:6701 Archived-At: On Mo, 2014-12-08 at 11:25 -0500, Rich Felker wrote: > On Mon, Dec 08, 2014 at 05:18:41PM +0100, Jörg Krause wrote: > > On Mo, 2014-12-08 at 09:56 -0500, Rich Felker wrote: > > > On Mon, Dec 08, 2014 at 03:42:25PM +0100, Jörg Krause wrote: > > > > Why does musl declares pthread_equal both as macro and as function? > > > > > > C and POSIX allow any of their standard functions to be provided as > > > macros too, but the function definition must always be provided. The > > > reason I put the macro in musl is simply that it's easy to do and > > > gives better code (trivial inline comparison rather than spilling all > > > registers and making a function call) and it's not something where the > > > implementation could change or need to change. > > > > I see! The problem was, that MPD (Music Player Daemon, implemented in C > > ++) for instance used ::pthread_equal(id, other_id) which did not build > > with musl because of the macro expansion. > > > > The maintainer removed the namespace operator to get it work with musl: > > http://git.musicpd.org/cgit/master/mpd.git/commit/?h=v0.18.x&id=d8fc2db910a11dbbba53ba7ecf96d0e32a081076 > > I see. > > For the standard C headers, the C++ versions are supposed to omit the > macros that the C versions might offer. However, there's no such rule > for POSIX headers since there's no formal spec for interaction of C++ > and POSIX at all. Perhaps it would be useful to take the same approach > and suppress such macros if __cplusplus is defined, even in the POSIX > headers? But I think from an application portability perspective, they > should either use #undef or parens, i.e. (::pthread_equal)(id1,id2), > instead of assuming there is no macro. > > Rich >From an application developer point of view I would look at the POSIX specification which says pthread_equal is a function defined as: int pthread_equal(pthread_t t1, pthread_t t2) I also proposed the solution with the parentesis. But in my opinion it is a little bit confusing for an application developer to assume a function specified by POSIX may be implemented as a macro.