The zmq_msg_gets() function shall return the string value for the metadata property specified by the property argument for the message pointed to by the message argument. Both the property argument and the value shall be NULL-terminated UTF8-encoded strings.
Metadata is defined on a per-connection basis during the ZeroMQ connection handshake as specified in <rfc.zeromq.org/spec:37>.
The following ZMTP properties can be retrieved with the zmq_msg_gets() function:
Additionally, when available for the underlying transport, the Peer-Address property will return the IP address of the remote endpoint as returned by getnameinfo(2).
Other properties may be defined based on the underlying security mechanism, see ZAP authenticated connection sample below.