http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52104
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-02-03
10:48:16 UTC ---
Are you sure this is using native TLS?
This part of the 49204 commit:
(__future_base::_Async_state_common::_M_join): Serialize attempts to
join thread.
adds:
void _M_join() { std::call_once(_M_once, &thread::join, ref(_M_thread)); }
which is called from the destructor, which is defined in future.o
That calls call_once, which creates the missing symbol:
template<typename _Callable, typename... _Args>
void
call_once(once_flag& __once, _Callable&& __f, _Args&&... __args)
{
#ifdef _GLIBCXX_HAVE_TLS
auto __bound_functor = std::__bind_simple(std::forward<_Callable>(__f),
std::forward<_Args>(__args)...);
__once_callable = &__bound_functor;
__once_call = &__once_call_impl<decltype(__bound_functor)>;
#else
unique_lock<mutex> __functor_lock(__get_once_mutex());
auto __callable = std::__bind_simple(std::forward<_Callable>(__f),
std::forward<_Args>(__args)...);
__once_functor = [&]() { __callable(); };
__set_once_functor_lock_ptr(&__functor_lock);
#endif
So the lambda and std::function are only used when _GLIBCXX_HAVE_TLS is not
defined
