From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30283 invoked by alias); 10 Apr 2015 00:16:11 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 30265 invoked by uid 89); 10 Apr 2015 00:16:10 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.8 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-Spam-User: qpsmtpd, 2 recipients X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Fri, 10 Apr 2015 00:16:10 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id C6347A0B91; Fri, 10 Apr 2015 00:16:08 +0000 (UTC) Received: from [10.36.6.233] (vpn1-6-233.ams2.redhat.com [10.36.6.233]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t3A0G72R020310; Thu, 9 Apr 2015 20:16:07 -0400 Subject: Re: [patch] Fix shared_timed_mutex::try_lock_until() et al From: Torvald Riegel To: Jonathan Wakely Cc: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org In-Reply-To: <20150408193808.GR9755@redhat.com> References: <20150407142830.GG9755@redhat.com> <1428512373.924.26.camel@triegel.csb> <20150408191159.GQ9755@redhat.com> <20150408193808.GR9755@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 10 Apr 2015 00:16:00 -0000 Message-ID: <1428624966.924.32.camel@triegel.csb> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-04/txt/msg00425.txt.bz2 On Wed, 2015-04-08 at 20:38 +0100, Jonathan Wakely wrote: > On 08/04/15 20:11 +0100, Jonathan Wakely wrote: > >We can get rid of the _Mutex type then, and just use std::mutex, and > >that also means we can provide the timed locking functions even when > >!defined(_GTHREAD_USE_MUTEX_TIMEDLOCK). > > > >And so maybe we should use this fallback implementation instead of > the > >pthread_rwlock_t one when !defined(_GTHREAD_USE_MUTEX_TIMEDLOCK), so > >that they have a complete std::shared_timed_mutex (this applies to at > >least Darwin, not sure which other targets). > > Here's a further patch to do that (which really needs to go into 5.0 > too, so we don't switch Darwin to the new pthread_rwlock_t version and > then have to swtich it back again in 6.0). I understand why a mutex with timeouts isn't required anymore, but why do you now add it to the USE_PTHREAD_RWLOCK_T condition? If pthread_rwlock_t is available, why would we need a normal mutex with timeouts? For example, this chunk here (and others too): > diff --git a/libstdc++-v3/include/std/shared_mutex b/libstdc > ++-v3/include/std/shared_mutex > index 7f26465..351a4f6 100644 > --- a/libstdc++-v3/include/std/shared_mutex > +++ b/libstdc++-v3/include/std/shared_mutex > @@ -57,7 +57,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > /// shared_timed_mutex > class shared_timed_mutex > { > -#ifdef _GLIBCXX_USE_PTHREAD_RWLOCK_T > +#if defined(_GLIBCXX_USE_PTHREAD_RWLOCK_T) && > _GTHREAD_USE_MUTEX_TIMEDLOCK > typedef chrono::system_clock __clock_t; > > #ifdef PTHREAD_RWLOCK_INITIALIZER