Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 19 Apr 2001 15:37:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 19 Apr 2001 15:36:50 -0400 Received: from router-100M.swansea.linux.org.uk ([194.168.151.17]:16911 "EHLO the-village.bc.nu") by vger.kernel.org with ESMTP id ; Thu, 19 Apr 2001 15:36:32 -0400 Subject: Re: light weight user level semaphores To: drepper@cygnus.com Date: Thu, 19 Apr 2001 20:35:59 +0100 (BST) Cc: torvalds@transmeta.com (Linus Torvalds), viro@math.psu.edu (Alexander Viro), abramo@alsa-project.org (Abramo Bagnara), alonz@nolaviz.org (Alon Ziv), linux-kernel@vger.kernel.org (Kernel Mailing List), mkravetz@sequent.com (Mike Kravetz) In-Reply-To: from "Ulrich Drepper" at Apr 19, 2001 12:26:03 PM X-Mailer: ELM [version 2.5 PL1] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: From: Alan Cox Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > I fail to see how this works across processes. How can you generate a > file descriptor for this pipe in a second process which simply shares > some memory with the first one? The first process is passive: no file > descriptor passing must be necessary. mknod foo p. Or use sockets (although AF_UNIX sockets are higher latency) Thats why I suggested using flock - its name based. Whether you mkstemp() stuff and pass it around isnt something I care about Files give you permissions for free too > Note that semaphores need not always be shared between processes. > This is a property the user has to choose. So the implementation can > be easier in the normal intra-process case. So you have unix file permissions on them ? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/