Mastering Linux Kernel Development

Message queues

Message queues are lists of message buffers through which an arbitrary number of processes can communicate. Unlike pipes, the writer does not have to wait for the reader to open the pipe and listen for data. Similar to a mailbox, writers can drop a fixed-length message wrapped in a buffer into the queue, which the reader can pick whenever it is ready. The message queue does not retain the message packet after it is picked by the reader, which means that each message packet is assured to be process persistent. Linux supports two distinct implementations of message queues: classic Unix SYSV message queues and contemporary POSIX message queues.