#include <pthread.h> int pthread_rwlock_destroy(pthread_rwlock_t **rwlock);
The effect of subsequent use of the lock is undefined until the lock is re-initialized by another call to pthread_rwlock_init(). An implementation can cause pthread_rwlock_destroy() to set the object referenced by rwlock to an invalid value. Results are undefined if pthread_rwlock_destroy() is called when any thread holds rwlock. Attempting to destroy an uninitialized read-write lock results in undefined behavior. A destroyed read-write lock object can be re-initialized using pthread_rwlock_init(). The results of otherwise referencing the read-write lock object after the lock object has been destroyed are undefined.