pthread_mutex_destroy   Destroys a mutex.

   pthread_mutex_init      Initializes a mutex with attributes
                           specified by the attributes argument.

   pthread_mutex_lock      Locks an unlocked mutex; if locked, the
                           caller waits for the mutex to become
                           available.

   pthread_mutex_trylock   Attempts to lock a mutex; returns
                           immediately if mutex is already locked.

   pthread_mutex_unlock    Unlocks a locked mutex.