From owner-freebsd-hackers@FreeBSD.ORG Fri Feb 9 05:08:07 2007 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id BB4DC16A400 for ; Fri, 9 Feb 2007 05:08:07 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from mxout1.cac.washington.edu (mxout1.cac.washington.edu [140.142.32.134]) by mx1.freebsd.org (Postfix) with ESMTP id 963D313C47E for ; Fri, 9 Feb 2007 05:08:07 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from smtp.washington.edu (smtp.washington.edu [140.142.32.141] (may be forged)) by mxout1.cac.washington.edu (8.13.7+UW06.06/8.13.7+UW06.09) with ESMTP id l195870c010523 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 8 Feb 2007 21:08:07 -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 l19586XU013548 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Thu, 8 Feb 2007 21:08:06 -0800 Message-ID: <45CC01B0.8050502@u.washington.edu> Date: Thu, 08 Feb 2007 21:08:00 -0800 From: Garrett Cooper User-Agent: Thunderbird 1.5.0.9 (X11/20070122) MIME-Version: 1.0 To: freebsd-hackers@freebsd.org References: <87D4B047-DC72-427B-863F-A082C3A4E5CD@u.washington.edu> <45CB38D8.1000706@u.washington.edu> <45CC014B.9020303@u.washington.edu> In-Reply-To: <45CC014B.9020303@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-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Feb 2007 05:08:07 -0000 Garrett Cooper wrote: > 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