pthread_rwlockattr_init( ) function shall initialize a read-write lock attributes object attr with the default value for all of the attributes defined by the implementation. After a read-write lock attributes object has been used to initialize one or more read-write locks, any function affecting the attributes object (including destruction) shall not affect any previously initialized read-write locks. If successful, the pthread_rwlockattr_init( ) functions shall return zero; otherwise, an error number shall be returned to indicate the error. pthread_rwlockattr_init( ) function shall fail if: [ENOMEM] Insufficient memory exists to initialize the read-write lock attributes object. This function shall not return an error code of [EINTR].