title: How do I synchronize access to shared memory in LynxOS/POSIX?
body: <p>I am implementing two processes on a <a href="http://www.lynuxworks.com/rtos/rtos-se.php" rel="noreferrer">LynxOS SE</a> (POSIX conformant) system that will communicate via shared memory.</p>
  
  <p>One process will act as a "producer" and the other a "consumer". In a multi-threaded system my approach to this would be to use a mutex and condvar (condition variable) pair, with the consumer waiting on the condvar (with <code>pthread_cond_wait</code>) and the producer signalling it (with <code>pthread_cond_signal</code>) when the shared memory is updated.</p>
  
  <p>How do I achieve this in a multi-process, rather than multi-threaded, architecture?  </p>
  
  <p>Is there a LynxOS/POSIX way to create a condvar/mutex pair that can be used between processes?<br>
  Or is some other synchronization mechanism more appropriate in this scenario?</p>