pthread_rwlockattr_init(3C) initializes a read-write lock attributes object attr with the default value for all of the attributes defined by the implementation.
#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.
Insufficient memory exists to initialize the read-write attributes object.