= zmq_unbind(3)


== NAME
zmq_unbind - Stop accepting connections on a socket


== SYNOPSIS
int zmq_unbind (void '*socket', const char '*endpoint');


== DESCRIPTION
The _zmq_unbind()_ function shall unbind a socket specified
by the 'socket' argument from the endpoint specified by the 'endpoint'
argument. 

Additionally the incoming message queue associated with the endpoint will be
discarded. This means that after unbinding an endpoint it is possible to
received messages originating from that same endpoint if they were already
present in the incoming message queue before unbinding.

The 'endpoint' argument is as described in xref:zmq_bind.adoc[zmq_bind]

Unbinding wild-card address from a socket
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When wild-card `*` 'endpoint' (described in xref:zmq_tcp.adoc[zmq_tcp],
xref:zmq_ipc.adoc[zmq_ipc], xref:zmq_udp.adoc[zmq_udp] and xref:zmq_vmci.adoc[zmq_vmci]) was used in
_zmq_bind()_, the caller should use real 'endpoint' obtained from the 
ZMQ_LAST_ENDPOINT socket option to unbind this 'endpoint' from a socket.

== RETURN VALUE
The _zmq_unbind()_ function shall return zero if successful. Otherwise it
shall return `-1` and set 'errno' to one of the values defined below.

== ERRORS
*EINVAL*::
The endpoint supplied is invalid.
*ETERM*::
The 0MQ 'context' associated with the specified 'socket' was terminated.
*ENOTSOCK*::
The provided 'socket' was invalid.
*ENOENT*::
The endpoint supplied was not previously bound.


== EXAMPLES
.Unbind a subscriber socket from a TCP transport
----
/* Create a ZMQ_SUB socket */
void *socket = zmq_socket (context, ZMQ_SUB);
assert (socket);
/* Connect it to the host server001, port 5555 using a TCP transport */
rc = zmq_bind (socket, "tcp://127.0.0.1:5555");
assert (rc == 0);
/* Disconnect from the previously connected endpoint */
rc = zmq_unbind (socket, "tcp://127.0.0.1:5555");
assert (rc == 0);
----

.Unbind wild-card `*` binded socket
----
/* Create a ZMQ_SUB socket */
void *socket = zmq_socket (context, ZMQ_SUB);
assert (socket);
/* Bind it to the system-assigned ephemeral port using a TCP transport */
rc = zmq_bind (socket, "tcp://127.0.0.1:*");
assert (rc == 0);
/* Obtain real endpoint */
const size_t buf_size = 32;
char buf[buf_size];
rc = zmq_getsockopt (socket, ZMQ_LAST_ENDPOINT, buf, (size_t *)&buf_size);
assert (rc == 0);
/* Unbind socket by real endpoint */
rc = zmq_unbind (socket, buf);
assert (rc == 0);
----

== NOTE

Note that while the implementation is similar to _zmq_disconnect()_, the
semantics are different and the two functions should not be used
interchangeably. Bound sockets should be unbound, and connected sockets should
be disconnected.

== SEE ALSO
* xref:zmq_bind.adoc[zmq_bind]
* xref:zmq_socket.adoc[zmq_socket]
* xref:zmq.adoc[zmq]


== AUTHORS
This page was written by the 0MQ community. To make a change please
read the 0MQ Contribution Policy at <https://zeromq.org/how-to-contribute/>.
