title: A mutex can only be released from the same thread that waited on it?
body: <p>Is it true that a mutex can only be released from the thread that wait on that mutex? If yes why the mutex behaves like this? So why we say a mutex can work across multiple processes? What is named-mutex and unnamed-mutex? I'm really confused about this issue!</p>
  
  <p>If I want to wait on mutex in a thread and signal it from another thread, what should I do?</p>