---
name: "zmq_unbind"
section: "3"
platform: "linux"
package: "zeromq"
version: "4.3.5-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/zmq_unbind"
---

# zmq\_unbind(3)

Stop accepting connections on a socket

## 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 [**zmq\_bind**(3)](/zmq_bind/3.md)

### Unbinding wild-card address from a socket

When wild-card \* *endpoint* (described in [**zmq\_tcp**(7)](/zmq_tcp/7.md), [**zmq\_ipc**(7)](/zmq_ipc/7.md), [**zmq\_udp**(7)](/zmq_udp/7.md) and [**zmq\_vmci**(7)](/zmq_vmci/7.md)) 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

[**zmq\_bind**(3)](/zmq_bind/3.md) [**zmq\_socket**(3)](/zmq_socket/3.md) [**zmq**(7)](/zmq/7.md)

## AUTHORS

This page was written by the 0MQ community. To make a change please read the 0MQ Contribution Policy at **http://www.zeromq.org/docs:contributing**.