* Re: std::jthread::operator=(std::jthread&&) calls std::terminate if *this has an associated running thread.
[not found] ` <5fa7f7cf.1c69fb81.d14a.c5c9@mx.google.com>
@ 2020-11-11 11:15 ` Jonathan Wakely
0 siblings, 0 replies; only message in thread
From: Jonathan Wakely @ 2020-11-11 11:15 UTC (permalink / raw)
To: Paul Scharnofske; +Cc: libstdc++, gcc-patches
On 08/11/20 14:51 +0100, Paul Scharnofske via Libstdc++ wrote:
>>I think this would work:
>>
>> jthread& operator=(jthread&& __x) noexcept
>> {
>> std::jthread(std::move(__x)).swap(*this);
>> return *this;
>> }
>
>That looks a lot better than what I did, it's also consistent with other
>places like std::stop_token::operator=(std::stop_token&&).
>
>I updated my patch and also created a test that checks the post
>conditions described in the standard.
Thanks, I've committed the patch and will also backport it to the
gcc-10 branch.
This patch is small enough to not require a copyright assignment, but
if you would like to make further contritbutions please contact me
off-list to discuss the legal prerequisites as described at
https://gcc.gnu.org/contribute.html
Thanks again for contributing to GCC!
>---
> libstdc++-v3/include/std/thread | 6 +++++-
> .../testsuite/30_threads/jthread/jthread.cc | 20 +++++++++++++++++++
> 2 files changed, 25 insertions(+), 1 deletion(-)
>
>diff --git a/libstdc++-v3/include/std/thread b/libstdc++-v3/include/std/thread
>index 887ee579962..080036e2609 100644
>--- a/libstdc++-v3/include/std/thread
>+++ b/libstdc++-v3/include/std/thread
>@@ -456,7 +456,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> operator=(const jthread&) = delete;
>
> jthread&
>- operator=(jthread&&) noexcept = default;
>+ operator=(jthread&& __other) noexcept
>+ {
>+ std::jthread(std::move(__other)).swap(*this);
>+ return *this;
>+ }
>
> void
> swap(jthread& __other) noexcept
>diff --git a/libstdc++-v3/testsuite/30_threads/jthread/jthread.cc b/libstdc++-v3/testsuite/30_threads/jthread/jthread.cc
>index 746ff437c1d..b8ba62f6df2 100644
>--- a/libstdc++-v3/testsuite/30_threads/jthread/jthread.cc
>+++ b/libstdc++-v3/testsuite/30_threads/jthread/jthread.cc
>@@ -187,6 +187,25 @@ void test_detach()
> VERIFY(t1FinallyInterrupted.load());
> }
>
>+//------------------------------------------------------
>+
>+void test_move_assignment()
>+{
>+ std::jthread thread1([]{});
>+ std::jthread thread2([]{});
>+
>+ const auto id2 = thread2.get_id();
>+ const auto ssource2 = thread2.get_stop_source();
>+
>+ thread1 = std::move(thread2);
>+
>+ VERIFY(thread1.get_id() == id2);
>+ VERIFY(thread2.get_id() == std::jthread::id());
>+
>+ VERIFY(thread1.get_stop_source() == ssource2);
>+ VERIFY(!thread2.get_stop_source().stop_possible());
>+}
>+
> int main()
> {
> std::set_terminate([](){
>@@ -197,4 +216,5 @@ int main()
> test_stop_token();
> test_join();
> test_detach();
>+ test_move_assignment();
> }
>--
>2.29.2
>
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[not found] ` <5fa7f7cf.1c69fb81.d14a.c5c9@mx.google.com>
2020-11-11 11:15 ` std::jthread::operator=(std::jthread&&) calls std::terminate if *this has an associated running thread Jonathan Wakely
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