C++ named requirements: SharedTimedLockable (od C++14)

The SharedTimedLockable requirements describe the characteristics of types that provide timed shared blocking semantics for execution agents (threads, processes, tasks).

Requirements

• SharedLockable

For type L to be SharedTimedLockable, given

• rel_time, a value of a specialization of std::chrono::duration, and
• abs_time, a value of a specialization of std::chrono::time_point,

the following conditions have to be satisfied for an object m of type L:

Expression	Requires	Return value
m.try_lock_shared_for(rel_time)	Blocks for the provided duration rel_time or until a lock on m is acquired.	true if the lock was acquired, false otherwise.
m.try_lock_shared_until(abs_time)	Blocks until the provided time point abs_time is reached or a lock on m is acquired.	true if the lock was acquired, false otherwise.

Notes

The try_lock_shared_for and try_lock_shared_until member functions obtain a shared lock on m on succcess.