I recall using this on a SunOS 3.x system (BSD 4.2-based) to build a message passing system. Over the years I expected it to be used more often for machine-inte

I recall using this on a SunOS 3.x system (BSD 4.2-based) to build a message passing system. Over the years I expected it to be used more often for machine-internal communication. I think it was overshadowed by its sibling the network socket because that could be used for local as well as network communication.