VxWorks, at least as used in the 6.8 CI, has a problem with move-only
lambdas passed to QThread::create(). This might have been the reason
for the resurrection of the cxx11_future feature in
408430a543ef605157963b1a894847c7ba9f9956.
This patch tries to work around the issue by not moving the promise
into the lambda capture, but caputuring it by reference, and then
moving it into a local stack variable. In all cases, the ThreadWrapper
is created after the promise, so, since the ThreadWrapper dtor join()s
(like jthread), the promise out-lives the thread, and the destruction
of the promise happens-after the join() with the thread. So, no data
races. Code mustn't touch the promise object from the main thread once
the ThreadWrapper has started, but that's the case already and the
test functions are small enough for any such future use to be obvious
in review.
Amends 385f0732d9 and
4e1b20893aeeb9580bc6b52ac4baea297675bfee.
It appears that dev no longer has the problem¹, but apply this to dev,
too, to maintain consistency with the test in last three LTS releases.
¹ 4e1b20893aeeb9580bc6b52ac4baea297675bfee passed, but its cherry-pick
to 6.8 did not
Pick-to: 6.5 6.2
Change-Id: If1feba9d3a7f8677789d45fa9f4990cf44145709
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
(cherry picked from commit 4d6cf54664a98e01d4caab42431c62d6deb9f86e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
44d4d2593c