C++ named requirements: TimedMutex
From cppreference.com
The TimedMutex requirements extend the TimedLockable requirements to include inter-thread synchronization.
Requirements
Additionally, for an object m
of TimedMutex type:
- The expression m.try_lock_for(duration) has the following properties
- Behaves as an atomic operation.
- Attempts to obtain exclusive ownership of the mutex within the duration specified by
duration
. Ifduration
is less or equalduration.zero()
, attempts to obtain the ownership without blocking (as if bytry_lock()
). Otherwise, this function blocks until the mutex is acquired or until the time specified byduration
passes. It returns withinduration
only if it succeeds, but it is allowed to fail to acquire the mutex even if at some point in time duringduration
it was not owned by another thread. In any case, it returns true if the mutex was acquired and false otherwise. - If
try_lock_for(duration)
succeeds, priorunlock()
operations on the same object synchronize-with this operation (equivalent to release-acquire std::memory_order). - The behavior is undefined if the calling thread already owns the mutex (except if m is std::recursive_timed_mutex).
- An exception may be thrown by clock, time point, or duration during the execution (clocks, time points, and durations provided by the standard library never throw).
- The expression m.try_lock_until(time_point) has the following properties
- Behaves as an atomic operation.
- Attempts to obtain exclusive ownership of the mutex within the time left until
time_point
. Iftime_point
already passed, attempts to obtain the ownership without blocking (as if bytry_lock()
). Otherwise, this function blocks until the mutex is acquired or until the time specified bytime_point
passes. It returns beforetime_point
only if it succeeds, but it is allowed to fail to acquire the mutex even if at some point in time beforetime_point
it was not owned by another thread. In any case, it returns true if the mutex was acquired and false otherwise. - If
try_lock_until(time_point)
succeeds, priorunlock()
operations on the same object synchronize-with this operation (equivalent to release-acquire std::memory_order). - The behavior is undefined if the calling thread already owns the mutex (except if m is std::recursive_timed_mutex).
- An exception may be thrown by clock, time point, or duration during the execution (clocks, time points, and durations provided by the standard library never throw).
Library types
The following standard library types satisfy TimedMutex:
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
LWG 2093 | C++11 | timeout-related exceptions were missing in the specification | mentioned |