From owner-svn-src-head@FreeBSD.ORG Tue Dec 8 22:10:30 2009 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1646F106568F; Tue, 8 Dec 2009 22:10:30 +0000 (UTC) (envelope-from jilles@stack.nl) Received: from mx1.stack.nl (relay04.stack.nl [IPv6:2001:610:1108:5010::107]) by mx1.freebsd.org (Postfix) with ESMTP id CE6C48FC1C; Tue, 8 Dec 2009 22:10:29 +0000 (UTC) Received: from toad.stack.nl (toad.stack.nl [IPv6:2001:610:1108:5010::135]) by mx1.stack.nl (Postfix) with ESMTP id D522C1DD635; Tue, 8 Dec 2009 23:10:28 +0100 (CET) Received: by toad.stack.nl (Postfix, from userid 1677) id CC52073FA4; Tue, 8 Dec 2009 23:10:28 +0100 (CET) Date: Tue, 8 Dec 2009 23:10:28 +0100 From: Jilles Tjoelker To: John Baldwin Message-ID: <20091208221028.GA57735@stack.nl> References: <200912082048.nB8Km6aP099420@svn.freebsd.org> <200912081645.37356.jhb@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200912081645.37356.jhb@freebsd.org> User-Agent: Mutt/1.5.18 (2008-05-17) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r200274 - head/lib/libc/gen X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Dec 2009 22:10:30 -0000 On Tue, Dec 08, 2009 at 04:45:37PM -0500, John Baldwin wrote: > On Tuesday 08 December 2009 3:48:06 pm Jilles Tjoelker wrote: > > Author: jilles > > Date: Tue Dec 8 20:48:06 2009 > > New Revision: 200274 > > URL: http://svn.freebsd.org/changeset/base/200274 > > Log: > > sem_init(3): document process shared semaphores and their restrictions > I think the other language was more accurate. The new language has > far less detail such as no longer documenting EPERM. It seems that EPERM longer happens, at least not for any process-shared semaphore at all. What's missing is the SIGSYS/ENOSYS you'll get if sem.ko is not loaded, and you're requesting a process-shared semaphore or not linking with the threading library. > I think it is also quite accurate to say that the current > implementation is not capable of process shared semaphores. Several > things would need to be changed including moving away from using file > descriptors. There are some lines of code dedicated to make it work, and some people seem to use it, although they notice that it does not work very well. This topic has come up on the mailing lists several times recently. -- Jilles Tjoelker