pthread_rwlock_init(2)                           pthread_rwlock_init(2)

  pthread_rwlock_destroy()

  NAME

    pthread_rwlock_destroy(), pthread_rwlock_init() - initialize or destroy a
    read-write lock object

  SYNOPSIS

    #include 

    int pthread_rwlock_destroy(pthread_rwlock_t *lock);
    int pthread_rwlock_init(pthread_rwlock_t *lock,
         const pthread_rwlockattr_t *attr);

  DESCRIPTION

    The pthread_rwlock_init(2) function initializes the read-write lock object
    referenced by the lock argument using the attributes specified by the
    read=-write lock attributes object referenced by the attr argument or, if
    attr is null, using default attributes. Once initialized, the read-write
    lock referenced by lock can be used multiple times without having to be
    reinitialized.

    The pthread_rwlock_destroy(2) function destroys the read-write lock object
    referenced by the lock argument. A read-write lock object should not be
    destroyed if any thread holds the lock.

  RETURN VALUES

    On success, both functions return 0; otherwise, an error code is returned.

  ERRORS

    The pthread_rwlock_destroy() function can fail for the following reasons:

    [EBUSY]
        The specified read-write lock object is in use.

    [EINVAL]
        The lock argument does not refer to a valid read-write lock object.

    The pthread_rwlock_init() function can fail for the following reasons:

    [EAGAIN]
        The system does not have sufficient resources, other than memory, to
        initialize the read-write lock object.

    [EBUSY]
        An attempt was made to reinitialize an existing read-write lock
        object.

    [EINVAL]
        The lock argument does not refer to a valid read-write lock object.

    [ENOMEM]
        Not enough free memory is available to initialize the read-write lock
        object.

    [EPERM]
        The caller does not have the permissions required to perform the
        operation.

    Neither function returns [EINTR].

  SEE ALSO

    pthread_rwlock_rdlock()

    pthread_rwlock_timedrdlock()

    pthread_rwlock_timedwrlock()

    pthread_rwlock_tryrdlock()

    pthread_rwlock_trywrlock()

    pthread_rwlock_unlock()

    pthread_rwlock_wrlock()

    pthread_rwlockattr_destroy(2)

  USAGE NOTES

    All of these functions are thread safe.

    None of these functions are async-signal safe.