* include/std/shared_mutex (__shared_mutex_pthread,
__shared_mutex_cv): New helper types implementing the shared mutex
requirements.
(shared_mutex): New type for C++17.
(shared_timed_mutex): Derive from one of the new helper types.
* testsuite/30_threads/shared_mutex/cons/1.cc: New.
* testsuite/30_threads/shared_mutex/cons/assign_neg.cc: New.
* testsuite/30_threads/shared_mutex/cons/copy_neg.cc: New.
* testsuite/30_threads/shared_mutex/requirements/standard_layout.cc:
New.
* testsuite/30_threads/shared_mutex/try_lock/1.cc: New.
* testsuite/30_threads/shared_mutex/try_lock/2.cc: New.
From-SVN: r224158
* include/std/shared_mutex (shared_timed_mutex): Add comments to
explain the logic in the non-pthread_rwlock_t version.
(_Mutex): Remove redundant type.
(_M_n_readers): Rename to _S_max_readers.
(_M_write_entered, _M_readers): New convenience functions.
(lock, lock_shared, try_lock_shared, unlock_shared): Use convenience
functions. Use predicates with condition variables. Simplify bitwise
operations.
(try_lock_for, try_shared_lock_for): Convert duration to time_point
and call try_lock_until or try_shared_lock_until respectively.
(try_lock_until, try_shared_lock_until): Wait on the condition
variables until the specified time passes.
(unlock): Add Debug Mode assertion.
(unlock_shared): Add Debug Mode assertion.
* testsuite/30_threads/shared_timed_mutex/try_lock/3.cc: New.
From-SVN: r221970
PR libstdc++/57641
* include/std/mutex (timed_mutex, recursive_timed_mutex): Move common
functionality to new __timed_mutex_impl mixin. Overload try_lock_until
to handle conversion between different clocks. Replace constrained
__try_lock_for_impl overloads with conditional increment.
* include/std/shared_mutex (shared_mutex::_Mutex): Use the new mixin.
* testsuite/30_threads/timed_mutex/try_lock_until/57641.cc: New.
From-SVN: r200180