How to debug the wire protocol?

Hello,

I’ve sent a similar email to the general mailing list but got no reply.

I’m trying to write my own implementation of the wire protocol. I’m stuck at the Parse message where I send it to the server but always get the following error: “Could not parse statement invalid string in message”

Is there a way to see how Postgres parses the message? I’ve set logging to DEBUG5 but the only thing I can see in the logs is, among other things, the message

ERROR: invalid string in message
FATAL: invalid frontend message type 63

What is exactly wrong? Is there a way to log the parsing of the message, or should I create my own build of postgres with log statements where I need them?

Many thanks,