Unix-domain sockets does not support control data

[mikbras]

The Unix-domain sockets implementation does not support the passing of control data (ancillary data). Supporting passing of extra data is easy enough, but control data is typically used to pass socket descriptors from one process to another (which involves creating a socket on the receiving process and injecting an entry into the file descriptor table).

[radhikaj]

Control data is not enabled at all currently.