Summary

Message passing is an extremely powerful concept and is one of the main features on which QNX Neutrino (and indeed, all past QNX operating systems) is built.

With message passing, a client and a server exchange messages (thread-to-thread in the same process, thread-to-thread in different processes on the same node, or thread-to-thread in different processes on different nodes in a network). The client sends a message and blocks until the server receives the message, processes it, and replies to the client.

The main advantages of message passing are:

• The content of a message doesn't change based on the location of the destination (local versus networked).
• A message provides a “clean” decoupling point for clients and servers.
• Implicit synchronization and serialization helps simplify the design of your applications.