The zmq_connect() function shall connect the socket referenced by the socket argument to the endpoint specified by the endpoint argument.
The endpoint argument is a string consisting of two parts as follows: transport ://address. The transport part specifies the underlying transport protocol to use. The meaning of the address part is specific to the underlying transport protocol selected.
The following transports are defined:
inproc
local in-process (inter-thread) communication transport, see zmq_inproc(7)
ipc
local inter-process communication transport, see zmq_ipc(7)
tcp
unicast transport using TCP, see zmq_tcp(7)
pgm, epgm
reliable multicast transport using PGM, see zmq_pgm(7)
With the exception of ZMQ_PAIR sockets, a single socket may be connected to multiple endpoints using zmq_connect(), while simultaneously accepting incoming connections from multiple endpoints bound to the socket using zmq_bind(). Refer to zmq_socket(3) for a description of the exact semantics involved when connecting or binding a socket to multiple endpoints.