From owner-freebsd-questions@FreeBSD.ORG Fri Feb 9 05:06:26 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 9F16916A401 for ; Fri, 9 Feb 2007 05:06:26 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from mxout7.cac.washington.edu (mxout7.cac.washington.edu [140.142.32.178]) by mx1.freebsd.org (Postfix) with ESMTP id 7AB1313C49D for ; Fri, 9 Feb 2007 05:06:26 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from smtp.washington.edu (smtp.washington.edu [140.142.32.139]) by mxout7.cac.washington.edu (8.13.7+UW06.06/8.13.7+UW06.09) with ESMTP id l1956PAQ027531 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 8 Feb 2007 21:06:26 -0800 X-Auth-Received: from [192.168.10.41] (c-67-187-172-183.hsd1.ca.comcast.net [67.187.172.183]) (authenticated authid=youshi10) by smtp.washington.edu (8.13.7+UW06.06/8.13.7+UW06.09) with ESMTP id l1956Pnp032029 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Thu, 8 Feb 2007 21:06:25 -0800 Message-ID: <45CC014B.9020303@u.washington.edu> Date: Thu, 08 Feb 2007 21:06:19 -0800 From: Garrett Cooper User-Agent: Thunderbird 1.5.0.9 (X11/20070122) MIME-Version: 1.0 To: freebsd-questions@freebsd.org References: <87D4B047-DC72-427B-863F-A082C3A4E5CD@u.washington.edu> <45CB38D8.1000706@u.washington.edu> In-Reply-To: <45CB38D8.1000706@u.washington.edu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-PMX-Version: 5.3.0.289146, Antispam-Engine: 2.5.0.283055, Antispam-Data: 2007.2.8.205434 X-Uwash-Spam: Gauge=IIIIIII, Probability=7%, Report='__CP_URI_IN_BODY 0, __CT 0, __CTE 0, __CT_TEXT_PLAIN 0, __HAS_MSGID 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __SANE_MSGID 0, __USER_AGENT 0' Subject: Re: Trying to join an already exited pthread X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Feb 2007 05:06:26 -0000 Garrett Cooper wrote: > Garrett Cooper wrote: >> On Feb 7, 2007, at 1:51 PM, Steve Watt wrote: >> >>> In , >>> wrote: >>>> Just wondering: >>>> >>>> If I was to try and join a pthread that already exited, would there >>>> be an error >>>> message output and/or errno set to an error value, or would a system >>>> hang? >>> >>> Was the thread created with detach state set PTHREAD_CREATE_DETACHED or >>> PTHREAD_CREATE_JOINABLE? If it was PTHREAD_CREATE_JOINABLE, has the >>> thread already been joined? >>> >>> You should be able to join a thread that was created joinable, only >>> once. >>> If you join it again, or join a thread that was created detached, the >>> results are unspecified in POSIX. There is an error status that may >>> be returned, but it may do other bad things to your system. >>> >>> Note that pthread_join doesn't set errno; it returns an error value >>> directly. I would never expect the system to hang, though the >>> application >>> might. If your application is hanging, make sure that you're not trying >>> to call pthread_join from within a signal handler. >>> >>>> It this variable on Unix OSes? >>> >>> That the results are unspecified? No. What "unspecified" means? >>> Absolutely. >>> --Steve Watt KD6GGD PP-ASEL-IA ICBM: 121W 56' 57.5" / 37N >>> 20' 15.3" >>> Internet: steve @ Watt.COM Whois: SW32-ARIN >>> Free time? There's no such thing. It just comes in varying >>> prices... >> >> I asked this because I was short on time and so was the person who >> asked me earlier. I'm going to try giving the pthread exit and join a >> shot just to see whether or not this is true or not and then I'll >> report my results to the list. >> Thanks for the insight though--hopefully my results will yield a >> solid positive or negative to this being a problem. >> -Garrett > > Under Suse Linux there were absolutely no errors when I tried to do > this. I'll post a code snippet later. > -Garrett Ok, here's a link to my code: http://students.washington.edu/youshi10/posted/thread_test.c My results (FreeBSD): [root@hoover /home/gcooper]# ./tt Thread join detached Thread kill detached Joined thread yielded error code: 2 Trying to join the already joined thread yields error code: 0 My results (Suse Linux): # ./tt Thread join detached Thread kill detached Joined thread yielded error code: 0 Trying to join the already joined thread yields error code: 0 That was sure interesting.. is it supposed to error out or was it the remnant of an old error call? Probably the latter, but I was just curious.. -Garrett