void ctl_rwlock_claim_read_lock(CTL_RWLOCK_t *rwlock);
ctl_rwlock_claim_read_lock acquires a read lock on the read-write lock rwlock. ctl_rwlock_claim_read_lock will block waiting for any write lock on rwlock to be released and a read lock on rwlock to become available.
ctl_rwlock_claim_read_lock is equivalent to, and is implemented by, a call to ctl_rwlock_read_lock specifying CTL_TIMEOUT_INFINITE as the timeout type.
ctl_rwlock_claim_read_lock must not be called from an interrupt service routine.