NAME
zmq_socket - create 0MQ socket
SYNOPSIS
void *zmq_socket (void *context, int type);
DESCRIPTION
The zmq_socket() function shall create a 0MQ socket within the
specified context and return an opaque handle to the newly created
socket. The type argument specifies the socket type, which determines
the semantics of communication over the socket.
The following messaging patterns are defined:
Peer to peer pattern
The simplest messaging pattern, used for communicating between two
peers.
Socket type
ZMQ_P2P
Compatible peer sockets
ZMQ_P2P
A socket of type ZMQ_P2P can only be connected to a single peer at any
one time. No message routing or filtering is performed on messages sent
over a ZMQ_P2P socket.
Publish-subscribe pattern
The publish-subscribe pattern is used for one-to-many distribution of
data from a single publisher to multiple subscribers in a fanout
fashion.
Socket type
ZMQ_PUB
Compatible peer sockets
ZMQ_SUB
A socket of type ZMQ_PUB is used by a publisher to distribute data.
Messages sent are distributed in a fanout fashion to all connected
peers. The zmq_recv() function is not implemented for this socket type.
Socket type
ZMQ_SUB
Compatible peer sockets
ZMQ_PUB
A socket of type ZMQ_SUB is used by a subscriber to subscribe to data
distributed by a publisher. Initially a ZMQ_SUB socket is not
subscribed to any messages, use the ZMQ_SUBSCRIBE option of
zmq_setsockopt() to specify which messages to subscribe to. The
zmq_send() function is not implemented for this socket type.
Request-reply pattern
The request-reply pattern is used for sending requests from a client to
a service, and receiving subsequent replies to each request sent.
Socket type
ZMQ_REQ
Compatible peer sockets
ZMQ_REP
A socket of type ZMQ_REQ is used by a client to send requests to and
receive replies from a service. This socket type allows only an
alternating sequence of zmq_send(request) and subsequent
zmq_recv(reply) calls. Each request sent is load-balanced among all
connected services.
Socket type
ZMQ_REP
Compatible peer sockets
ZMQ_REQ
A socket of type ZMQ_REP is used by a service to receive requests from
and send replies to a client. This socket type allows only an
alternating sequence of zmq_recv(request) and subsequent
zmq_send(reply) calls. Each reply is routed to the client that issued
the last received request.
Parallelized pipeline pattern
The parallelized pipeline pattern is used for distributing work between
components of a pipeline. Work travels down the pipeline and at each
stage can be processed by any number of components in parallel.
Socket type
ZMQ_UPSTREAM
Compatible peer sockets
ZMQ_DOWNSTREAM
A socket of type ZMQ_UPSTREAM is used by a component of a pipeline to
receive messages from upstream stages of the pipeline. Messages are
fair-queued from among all connected upstream components. The
zmq_send() function is not implemented for this socket type.
Socket type
ZMQ_DOWNSTREAM
Compatible peer sockets
ZMQ_UPSTREAM
A socket of type ZMQ_DOWNSTREAM is used by a component of a pipeline to
send messages to downstream stages of the pipeline. Messages are
load-balanced to all connected downstream components. The zmq_recv()
function is not implemented for this socket type.
RETURN VALUE
The zmq_socket() function shall return an opaque handle to the newly
created socket if successful. Otherwise, it shall return NULL and set
errno to one of the values defined below.
ERRORS
EINVAL
The requested socket type is invalid.
EMTHREAD
The number of application threads using sockets within this context
has been exceeded. See the app_threads parameter of the zmq_init()
function.
SEE ALSO
zmq_init(3) zmq_setsockopt(3) zmq_bind(3) zmq_connect(3) zmq_send(3)
zmq_recv(3)
AUTHORS
The 0MQ documentation was written by Martin Sustrik
<sustrik@250bpm.com[1]> and Martin Lucina <mato@kotelna.sk[2]>.
NOTES
1. sustrik@250bpm.com
mailto:sustrik@250bpm.com
2. mato@kotelna.sk
mailto:mato@kotelna.sk