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From: Jonathan Wakely <jwakely@redhat.com>
To: Vladimir V <vv.os.swe@gmail.com>
Cc: libstdc++@gcc.gnu.org
Subject: Re: Problem building libstdc++ for the avr target
Date: Wed, 9 Dec 2020 12:49:33 +0000	[thread overview]
Message-ID: <20201209124933.GU2309743@redhat.com> (raw)
In-Reply-To: <CA+=iAip_JN164_kZhDsd-+ET12Atve7F3aJcnmKCikFteVdDDg@mail.gmail.com>

On 09/12/20 13:32 +0100, Vladimir V wrote:
>Hello.
>
>While testing with the current upstream I encountered a compilation issue.
>Although I build with "--disable-threads" flag the following error occurs:
>
>../../../../../libstdc++-v3/src/c++11/thread.cc:39:4: error: #error "No
>sleep function known for this target"
>
>Previously the check was inside the  #ifdef _GLIBCXX_HAS_GTHREADS that
>prevented the error from happening (in my case with gcc v10.1),
>So I would like to ask if the thread.cc should be involved in the build if
>the threads support is configured to be disabled?

Yes, the file is always built, but which definitions it contains
depends on what is configured for the target.

The std::this_thread::sleep_for and std::this_thread::sleep_until
functions don't actually depend on threads at all. They just sleep.

But that still requires target support, just different support from
threads.

>And if it should, then can the condition be reworked to cover the described
>case?

Yes, I'll do that. Thanks for bringing it to my attention.

I assume we can't use avr-libc's delay functions, because they depend
on the CPU clock frequency, which isn't known when we compile
libstdc++. So I'll just suppress the declarations of those functions
and remove the #error.



  reply	other threads:[~2020-12-09 12:49 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-07 17:32 Vladimir V
2020-12-07 20:30 ` Jonathan Wakely
2020-12-07 20:32   ` Jonathan Wakely
2020-12-09  0:28     ` Vladimir V
2020-12-09 12:32       ` Vladimir V
2020-12-09 12:49         ` Jonathan Wakely [this message]
2020-12-09 17:01           ` Jonathan Wakely
2020-12-09 23:00             ` Vladimir V
2020-12-10 17:39               ` Vladimir V
2020-12-10 20:15                 ` Jonathan Wakely
2020-12-10 20:31                   ` Vladimir V
2020-12-15 11:48                 ` Jonathan Wakely
2020-12-16  7:33                   ` Vladimir V
2020-12-07 20:41   ` Keith Packard
2020-12-07 21:06     ` Jonathan Wakely
2021-01-04 11:28       ` Vladimir V
2021-01-08 18:21         ` Jonathan Wakely
2021-01-22 14:46           ` Vladimir V
2021-02-07 13:55             ` Vladimir V
2021-02-07 18:22               ` Vladimir V
2021-02-07 18:23               ` Keith Packard
2021-02-07 22:33                 ` Vladimir V
2021-02-07 23:06                   ` Keith Packard
2021-02-08 12:58                     ` Vladimir V
2021-02-08 17:38                 ` Jonathan Wakely
2021-02-08 17:45               ` Jonathan Wakely
2021-02-08 17:47                 ` Jonathan Wakely
2021-02-08 22:25                   ` Vladimir V
2021-02-09 10:47                     ` Jonathan Wakely
2021-02-09 10:54                       ` Vladimir V
2021-03-25  9:27                         ` Vladimir V
2021-03-25 12:36                           ` Jonathan Wakely
2021-03-25 18:27                             ` Jonathan Wakely
2021-03-25 21:37                               ` Vladimir V
2021-03-25 23:02                                 ` Jonathan Wakely
2021-03-26  8:25                                   ` Vladimir V
2020-12-07 21:51     ` Vladimir V
2020-12-07 23:00       ` Keith Packard
2020-12-08  8:12         ` Vladimir V

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