Martin (or anyone else), What was the purpose of the extra byte in the IPC header that precedes the length (for each message). If not for that one difference, the message formats between IPC and TCP/TLS would be identical. I’m having a hard time seeing value in that extra byte. (I noticed this tonight when I was trying to use IPC between C and my Go version, and I discovered that while I tested TCP, apparently I never tested IPC interop… Oops!) -- Garrett D'Amore Sent with Airmail