std::recursive_timed_mutex::try_lock_until
| template< class Clock, class Duration > bool try_lock_until( const std::chrono::time_point<Clock, Duration>& timeout_time ); |
(since C++11) | |
Tries to lock the mutex. Blocks until specified timeout_time has been reached (timeout) or the lock is acquired (owns the mutex), whichever comes first. On successful lock acquisition returns true, otherwise returns false.
If timeout_time has already passed, this function behaves like try_lock().
Clock must meet the Clock requirements. The program is ill-formed if std::chrono::is_clock_v<Clock> is false.(since C++20)
The standard recommends that the clock tied to timeout_time be used, in which case adjustments of the clock may be taken into account. Thus, the duration of the block might be more or less than timeout_time - Clock::now() at the time of the call, depending on the direction of the adjustment and whether it is honored by the implementation. The function also may block until after timeout_time has been reached due to process scheduling or resource contention delays.
As with try_lock(), this function is allowed to fail spuriously and return false even if the mutex was not locked by any other thread at some point before timeout_time.
Prior unlock() operation on the same mutex synchronizes-with (as defined in std::memory_order) this operation if it returns true.
A thread may call try_lock_until on a recursive mutex repeatedly. Successful calls to try_lock_until increment the ownership count: the mutex will only be released after the thread makes a matching number of calls to unlock.
The maximum number of levels of ownership is unspecified. A call to try_lock_until will return false if this number is exceeded.
Parameters
| timeout_time | - | maximum time point to block until |
Return value
true if the lock was acquired successfully, otherwise false.
Exceptions
Any exception thrown by timeout_time (clocks, time points, and durations provided by the standard library never throw).
Example
| This section is incomplete Reason: no example |
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 | try_lock_until threw nothing
|
throws timeout-related exceptions |
See also
| locks the mutex, blocks if the mutex is not available (public member function) | |
| tries to lock the mutex, returns if the mutex is not available (public member function) | |
| tries to lock the mutex, returns if the mutex has been unavailable for the specified timeout duration (public member function) | |
| unlocks the mutex (public member function) | |
| C documentation for mtx_timedlock
| |