From: Jonathan Wakely <jwakely@redhat.com>
To: Tom Tromey <tom@tromey.com>
Cc: Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org>,
Jason Merrill <jason@redhat.com>,
Jakub Jelinek <jakub@redhat.com>,
John David Anglin <dave.anglin@bell.net>
Subject: Re: [PATCH] c++: Predefine __STDCPP_THREADS__ in the compiler if thread model is not single
Date: Mon, 16 Nov 2020 16:49:11 +0000 [thread overview]
Message-ID: <20201116164911.GA958467@redhat.com> (raw)
In-Reply-To: <87tutp1d9u.fsf@tromey.com>
On 16/11/20 09:23 -0700, Tom Tromey wrote:
>Jakub> If it is done in the library, it will be defined only if any of the library
>Jakub> headers are included.
>Jakub> The https://eel.is/c++draft/cpp.predefined wording doesn't look like it
>Jakub> would allow defining it only if certain headers are included
>Jakub> (unlike e.g. the __cpp_lib_* macros which have associated list of headers
>Jakub> that should define those).
>
>Also I was wondering if there's a C analogue.
>I found http://www.open-std.org/jtc1/sc22/WG14/www/docs/n2069.pdf but I
>have no idea whether this is just a paper or was adopted.
C11 and later say:
_ _STDC_NO_THREADS_ _ The integer constant 1, intended to indicate that the
implementation does not support the <threads.h> header.
You can probably guess how useful it is in practice:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53769
next prev parent reply other threads:[~2020-11-16 16:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 17:29 Jakub Jelinek
2020-11-13 18:20 ` Jeff Law
2020-11-13 19:03 ` John David Anglin
2020-11-13 19:05 ` Jeff Law
2020-11-13 19:20 ` Tom Tromey
2020-11-13 21:39 ` Jason Merrill
2020-11-13 21:46 ` Jakub Jelinek
2020-11-13 21:50 ` Jason Merrill
2020-11-13 22:52 ` Jonathan Wakely
2020-11-16 16:23 ` Tom Tromey
2020-11-16 16:49 ` Jonathan Wakely [this message]
2020-11-13 21:42 ` Jonathan Wakely
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