Using a relative path is more explicit and should avoid a potential
name clash in case if there appears a different b2 module with the same
name in a different search location.
Added a missing import-search directive to config/Jamfile so that
atomic-arch-config.jam is found when configure-time checks are invoked
from tests. This allows us to enable the type_traits check for tests.
Added is_trivially_copyable and is_trivially_default_constructible type
traits that rely on the non-standard type traits available in libstdc++
from gcc 4.8 and 4.9.
Rather than requiring cxx11_hdr_type_traits in the library and test
requirements, use a more limited test that checks only the type traits
we use in Boost.Atomic.
Similarly, downgrade the requirement of C++ unrestricted unions to
unions with members that have non-trivial default constructors.
Remove the requirements of alignas and alignof, since those are not
mandatory for now.
Closes https://github.com/boostorg/atomic/issues/74.
Added a configure test for pthread_cond_clockwait presence. If it is
available, use it for timed waits with absolute timeouts on POSIX platforms.
Futex-based implementation has been improvved to use proper atomic operations
to access m_cond, which is needed to avoid races between the futex syscall and
our notifying operations. Also, check if m_cond has changed whil looping in
the waiting operations.
This makes WaitOnAddress/WakeByAddressSingle/WakeByAddressAll a mandatory
requirement. Thus, runtime detection of these APIs is now removed.
Also, linking with synchronization lib on Windows is now mandatory. The
library provides WaitOnAddress & co. which are now mandatory.
When targeting Windows 8, the always_has_native_wait_notify static constant
would be set to false even though the native implementation of waiting
and notifying operations through WaitOnAddress would always be used.
To fix this, moved direct WaitOnAddress & co. usage to public header. This
also requires users to link with synchronization.lib, which is done
automatically on compilers that support auto-linking.
The compiled library still implements runtime detection of WaitOnAddress,
even when building for Windows 8 and later. This allows user's code to
be later compiled for Windows 7 and older and still work. This code is
not used when user's code targets Windows 8 or later.
As part of this refactoring, renamed has_synchronization test and
related CMake variable to better communicate that we're testing for
a library.
We need to explicitly link with synchronization.lib when the
WaitOnAddress API is enabled at compile time for ARM targets. Since
this library is only available on newer Windows SDKs, we have to perform
a configure check for whether it is available.
