Furthermore, on Linux, there is an extension: the first byte of sun_path can be null. In that case, the rest of the path is still valid up to the given length and specifies an "abstract address": it's a namespace outside of the filesystem. Sockets bound to abstract addresses automatically disappear on the last close.

This drives home the idea that "damn it, this is not a null terminated string; here is the null-byte-based extension to prove it!"