Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261826AbVEDNtx (ORCPT ); Wed, 4 May 2005 09:49:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261833AbVEDNtx (ORCPT ); Wed, 4 May 2005 09:49:53 -0400 Received: from alog0497.analogic.com ([208.224.223.34]:22241 "EHLO chaos.analogic.com") by vger.kernel.org with ESMTP id S261826AbVEDNtt (ORCPT ); Wed, 4 May 2005 09:49:49 -0400 Date: Wed, 4 May 2005 09:49:37 -0400 (EDT) From: "Richard B. Johnson" Reply-To: linux-os@analogic.com To: Jakub Jelinek cc: Linux kernel Subject: Re: System call v.s. errno In-Reply-To: <20050504134224.GE17420@devserv.devel.redhat.com> Message-ID: References: <20050504134224.GE17420@devserv.devel.redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1445 Lines: 34 On Wed, 4 May 2005, Jakub Jelinek wrote: > On Wed, May 04, 2005 at 09:22:09AM -0400, Richard B. Johnson wrote: >> Does anybody know for sure if global 'errno' is supposed to >> be altered after a successful system call? I'm trying to >> track down a problem where system calls return with EINTR >> even though all signal handlers are set with SA_RESTART in >> the flags. It appears as though there may be a race somewhere >> because if I directly set errno to 0x1234, within a few >> hundred system calls, it gets set to EINTR even though all >> system calls seemed to return 'good'. This makes it >> hard to trace down the real problem. > > http://www.opengroup.org/onlinepubs/009695399/functions/errno.html > is very clear on this. Unless indicated that errno is valid after a call > (for many syscalls it is valid when the syscall returns -1), errno has > unspecified value. > > Jakub > - Okay, thanks. That means that it's okay for it to get trashed NotGood(tm) for debugging. Cheers, Dick Johnson Penguin : Linux version 2.6.11 on an i686 machine (5537.79 BogoMips). Notice : All mail here is now cached for review by Dictator Bush. 98.36% of all statistics are fiction. - 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/