pthread_rwlockattr_init Syntax

#include <pthread.h>

int pthread_rwlockattr_init(pthread_rwlockattr_t *attr);

Results are undefined if pthread_rwlockattr_init is called specifying an already initialized read-write lock attributes object. After a read-write lock attributes object initializes one or more read-write locks, any function that affects the object, including destruction, does not affect previously initialized read-write locks.