libzmq/doc/zmq_recv.txt

zmq_recv(3)
===========


NAME
----
zmq_recv - receive a message from a socket


SYNOPSIS
--------
*int zmq_recv (void '*socket', zmq_msg_t '*msg', int 'flags');*


DESCRIPTION
-----------
The _zmq_recv()_ function shall dequeue a message from the underlying _message
queue_ associated with the socket referenced by the 'socket' argument and store
it in the message referenced by the 'msg' argument. Any content previously
stored in 'msg' shall be properly deallocated. If there are no messages
available to be dequeued from the underlying _message queue_ associated with
'socket' the _zmq_recv()_ function shall block until the request can be
satisfied. The 'flags' argument is a combination of the flags defined below:

*ZMQ_NOBLOCK*::
Specifies that the operation should be performed in non-blocking mode. If there
are no messages available to be dequeued from the underlying _message queue_
associated with 'socket', the _zmq_recv()_ function shall fail with 'errno' set
to EAGAIN.


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


ERRORS
------
*EAGAIN*::
Non-blocking mode was requested and no messages are available at the moment.
*ENOTSUP*::
The _zmq_recv()_ operation is not supported by this socket type.
*EFSM*::
The _zmq_recv()_ operation cannot be performed on this socket at the moment due
to the socket not being in the appropriate state.  This error may occur with
socket types that switch between several states, such as ZMQ_REP.  See the
_messaging patterns_ section of linkzmq:zmq_socket[3] for more information.


EXAMPLE
-------
.Receiving a message from a socket
----
/* Create an empty 0MQ message */
zmq_msg_t msg;
int rc = zmq_msg_init (&msg);
assert (rc == 0);
/* Block until a message is available to be dequeued from socket */
rc = zmq_recv (socket, &msg, 0);
assert (rc == 0);
----


SEE ALSO
--------
linkzmq:zmq_send[3]
linkzmq:zmq_socket[7]
linkzmq:zmq[7]


AUTHORS
-------
The 0MQ documentation was written by Martin Sustrik <sustrik@250bpm.com> and
Martin Lucina <mato@kotelna.sk>.