Attempts to acquire a read lock on the enclosing mutex. If one can
be obtained without blocking, the lock is acquired and true is
returned. If not, the function blocks until either the lock can be
obtained or the time elapsed exceeds timeout, returning
true if the lock was acquired and false if the function timed out.
Attempts to acquire a read lock on the enclosing mutex. If one can be obtained without blocking, the lock is acquired and true is returned. If not, the function blocks until either the lock can be obtained or the time elapsed exceeds timeout, returning true if the lock was acquired and false if the function timed out.