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Date: Tue, 2 Jan 2018 16:34:29 +0200
From: Konstantin Belousov <kostikbel@gmail.com>
To: Pierre DAVID <pdagog@gmail.com>
Cc: freebsd-current@freebsd.org
Subject: Re: Problem with C11 _Atomic
Message-ID: <20180102143429.GK1684@kib.kiev.ua>
References: <20180101204740.GA15590@vagabond>
 <20180101210907.GG1684@kib.kiev.ua>
 <20180102141714.GA16473@vagabond>
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On Tue, Jan 02, 2018 at 03:17:14PM +0100, Pierre DAVID wrote:
> On Mon, Jan 01, 2018 at 11:09:07PM +0200, Konstantin Belousov wrote:
> >clang issues a calls to libatomic, which we do not provide.
> >As a workaround, use the following command to compile.  The resulting
> >binary works on all practically usable machines.
> >	$ cc -march=core2 source.c
> >You might want to turn off sse3/4.1 if you are concerned about older pentium4.
> >
> 
> Thanks for your help. I wish that the C11 status of FreeBSD will soon
> be complete out of the box, without the help of such a hack.

This is not FreeBSD but clang.  Also I looked at the generated reference,
and the referenced symbol was absent in the gcc' 7.2.0 libatomic.

Same common problem with i386 and same cmpxchg8b is popular because the
default arch is i486.

This is a clang way of operations.