std::shared_timed_mutex::try_lock_shared_for
|   template< class Rep, class Period > bool try_lock_shared_for( const std::chrono::duration<Rep,Period>& timeout_duration );  | 
(since C++14) | |
Tries to lock the mutex in shared mode. Blocks until specified timeout_duration has elapsed or the shared lock is acquired, whichever comes first. On successful lock acquisition returns true, otherwise returns false. 
If timeout_duration is less or equal timeout_duration.zero(), the function behaves like try_lock_shared().
This function may block for longer than timeout_duration due to scheduling or resource contention delays. 
The standard recommends that a steady clock is used to measure the duration. If an implementation uses a system clock instead, the wait time may also be sensitive to clock adjustments.
As with try_lock_shared(), this function is allowed to fail spuriously and return false even if the mutex was not locked by any other thread at some point during timeout_duration.
Prior unlock() operation on the same mutex synchronizes-with (as defined in std::memory_order) this operation if it returns true.
If try_lock_shared_for is called by a thread that already owns the mutex in any mode (shared or exclusive), the behavior is undefined.
Parameters
| timeout_duration | - | maximum duration to block for | 
Return value
true if the lock was acquired successfully, otherwise false.
Exceptions
Any exception thrown by clock, time_point, or duration during the execution (clocks, time points, and durations provided by the standard library never throw)
Example
| This section is incomplete Reason: no example  | 
See also
|    tries to lock the mutex for shared ownership, returns if the mutex is not available  (public member function)  | |
|    tries to lock the mutex for shared ownership, returns if the mutex has been unavailable until specified time point has been reached (public member function)  | |
|    tries to lock the mutex, returns if the mutex has been unavailable for the specified timeout duration (public member function)  |