---
name: "zmq_vmci"
section: "7"
platform: "linux"
package: "zeromq"
version: "4.3.5-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/zmq_vmci"
---

# zmq\_vmci(7)

0MQ transport over virtual machine communicatios interface (VMCI) sockets

## NAME

zmq\_vmci - 0MQ transport over virtual machine communicatios interface (VMCI) sockets

## SYNOPSIS

The VMCI transport passes messages between VMware virtual machines running on the same host, between virtual machine and the host and within virtual machines (inter-process transport like ipc).

**Note**\

Communication between a virtual machine and the host is not supported on Mac OS X 10.9 and above.

## ADDRESSING

A 0MQ endpoint is a string consisting of a *transport*:// followed by an *address*. The *transport* specifies the underlying protocol to use. The *address* specifies the transport-specific address to connect to.

For the VMCI transport, the transport is vmci, and the meaning of the *address* part is defined below.

### Binding a socket

When binding a *socket* to a local address using *zmq\_bind()* with the *vmci* transport, the *endpoint* shall be interpreted as an *interface* followed by a colon and the TCP port number to use.

An *interface* may be specified by either of the following:

• The wild-card \*, meaning all available interfaces.

• An integer returned by VMCISock\_GetLocalCID or @ (ZeroMQ will call VMCISock\_GetLocalCID internally).

The port may be specified by:

• A numeric value, usually above 1024 on POSIX systems.

• The wild-card \*, meaning a system-assigned ephemeral port.

### Unbinding wild-card address from a socket

When wild-card \* *endpoint* 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 using *zmq\_unbind()*.

### Connecting a socket

When connecting a socket to a peer address using *zmq\_connect()* with the *vmci* transport, the *endpoint* shall be interpreted as a *peer address* followed by a colon and the port number to use.

A *peer address* must be a CID of the peer.

## EXAMPLES

**Assigning a local address to a socket**.

```
//  VMCI port 5555 on all available interfaces
rc = zmq_bind(socket, "vmci://*:5555");
assert (rc == 0);
//  VMCI port 5555 on the local loop-back interface on all platforms
cid = VMCISock_GetLocalCID();
sprintf(endpoint, "vmci://%d:5555", cid);
rc = zmq_bind(socket, endpoint);
assert (rc == 0);
```

**Connecting a socket**.

```
//  Connecting using a CID
sprintf(endpoint, "vmci://%d:5555", cid);
rc = zmq_connect(socket, endpoint);
assert (rc == 0);
```

## SEE ALSO

[**zmq\_bind**(3)](/zmq_bind/3.md) [**zmq\_connect**(3)](/zmq_connect/3.md) [**zmq\_inproc**(7)](/zmq_inproc/7.md) [**zmq\_tcp**(7)](/zmq_tcp/7.md) [**zmq\_pgm**(7)](/zmq_pgm/7.md) [**zmq\_vmci**(7)](/zmq_vmci/7.md) [**zmq\_getsockopt**(3)](/zmq_getsockopt/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**.