= zmq_vmci(7)


== 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
* xref:zmq_bind.adoc[zmq_bind]
* xref:zmq_connect.adoc[zmq_connect]
* xref:zmq_inproc.adoc[zmq_inproc]
* xref:zmq_tcp.adoc[zmq_tcp]
* xref:zmq_pgm.adoc[zmq_pgm]
* xref:zmq_vmci.adoc[zmq_vmci]
* xref:zmq_getsockopt.adoc[zmq_getsockopt]
* 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/>.
