Obtain a read lock on @rw_lock. If another thread currently holds
the write lock on @rw_lock or blocks waiting for it, the current
thread will block. Read locks can be taken recursively.
It is implementation-defined how many threads are allowed to
hold read locks on the same lock simultaneously. If the limit is hit,
or if a deadlock is detected, a critical warning will be emitted.
Obtain a read lock on @rw_lock. If another thread currently holds the write lock on @rw_lock or blocks waiting for it, the current thread will block. Read locks can be taken recursively.
It is implementation-defined how many threads are allowed to hold read locks on the same lock simultaneously. If the limit is hit, or if a deadlock is detected, a critical warning will be emitted.