cpp/thread/shared mutex/try lock shared

Tries to lock the mutex in shared mode. Returns immediately. On successful lock acquisition returns, otherwise returns.

This function is allowed to fail spuriously and return even if the mutex is not currenly exclusively locked by any other thread.

A prior unlock operation on the same mutex synchronizes-with (as defined in std) this operation if it returns.

The behavior is undefined if the calling thread already owns the mutex in any mode.

Parameters
(none)

Return value
if the lock was acquired successfully, otherwise.

Exceptions
Throws nothing.