SysV MessageQueue?
 

Unlike shared memory, we dont' need to do any sort of syncrhonization for Message Queue right?

No, you don't need real "synchronization". You can actually send a message to the queue, then exit, and start the receiving program a week later.

But you do need to read the messages from the queue on a regalar basis, because the space and/or the number of messages on the queue is limited.