From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756875AbZB1Co7 (ORCPT ); Fri, 27 Feb 2009 21:44:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754375AbZB1Cou (ORCPT ); Fri, 27 Feb 2009 21:44:50 -0500 Received: from mx1.redhat.com ([66.187.233.31]:57617 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754053AbZB1Cot (ORCPT ); Fri, 27 Feb 2009 21:44:49 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: mtk.manpages@gmail.com X-Fcc: ~/Mail/linus Cc: Thomas Gleixner , LKML , Oleg Nesterov , Ingo Molnar , Linux API , drepper@redhat.com Subject: Re: [patch 0/3] add rt_tgsigqueueinfo syscall [RESEND] In-Reply-To: Michael Kerrisk's message of Saturday, 28 February 2009 14:53:23 +1300 References: <20090226133339.875832967@linutronix.de> Emacs: more boundary conditions than the Middle East. Message-Id: <20090228024424.D237CFC3DA@magilla.sf.frob.com> Date: Fri, 27 Feb 2009 18:44:24 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > With respect to the first point, it seems to me reasonably likely that > there would be use cases where the receiving thread wants to know the > thread ID of the sender -- especially when sender and receiver are in > the same process. But expecting si_pid to play that role is bizarre. It's never what any POSIX-like program would do, both since POSIX says si_pid is a process ID, and because there are no POSIX-like interfaces at all that use Linux TIDs to refer to threads. Wanting this only seems plausible within one process. In that case, sender and recipient know they share memory. The normal thing to do (and what POSIX applications will do) is to store that info somewhere pointed to by the sigval. Thanks, Roland