From: Julien Ramseier <j.ramseier@gmail.com>
To: musl@lists.openwall.com
Subject: Re: Issues when building libcxx libcxxabi with MUSL
Date: Thu, 30 Jun 2016 14:50:14 +0200 [thread overview]
Message-ID: <8836ED26-349A-4701-9D7A-F1D2CF272A24@gmail.com> (raw)
In-Reply-To: <20160622194149.GU10893@brightrain.aerifal.cx>
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> Le 22 juin 2016 à 21:41, Rich Felker <dalias@libc.org> a écrit :
>
> On Wed, Jun 22, 2016 at 09:38:17PM +0200, Julien Ramseier wrote:
>> Hi Zhao,
>>
>> Not sure how you did build llvm-libcxx, but the only issue I encountered myself is
>> the use of PTHREAD_MUTEX_INITIALIZER in libcxx include/__mutex_base.
>> musl uses volatile types in its pthread_mutex_t struct and C++11 does not allow them
>> with constexpr member initializers. This rule has been relaxed in C++14.
>
> Note that the code using them is still formally/conceptually buggy.
> POSIX does not permit using these initializers as values. They can
> only be used as initializers for objects with static storage duration.
> A "mutex value" makes no sense; mutexes are objects not values.
Actually the latest POSIX spec allows it.
See http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutex_init.html <http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutex_init.html>
A workaround for the C++11 constexpr issue should land soon in libcxx trunk.
http://reviews.llvm.org/D21637 <http://reviews.llvm.org/D21637>
Julien
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next prev parent reply other threads:[~2016-06-30 12:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 19:24 Zhao, Weiming
2016-06-22 19:34 ` Rich Felker
2016-06-22 19:38 ` Julien Ramseier
2016-06-22 19:41 ` Rich Felker
2016-06-30 12:50 ` Julien Ramseier [this message]
2016-06-30 13:15 ` Szabolcs Nagy
2016-06-30 13:38 ` Szabolcs Nagy
2016-06-30 13:45 ` Rich Felker
2016-06-30 13:38 ` Rich Felker
2016-06-30 14:36 ` Julien Ramseier
2016-06-30 14:58 ` Rich Felker
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