ZMQ_SEND(3) | 0MQ Manual | ZMQ_SEND(3) |
NAME¶
zmq_send - send a message on a socketSYNOPSIS¶
int zmq_send (void *socket, zmq_msg_t *msg , int flags);DESCRIPTION¶
The zmq_send() function shall queue the message referenced by the msg argument to be sent to the socket referenced by the socket argument. The flags argument is a combination of the flags defined below: ZMQ_NOBLOCKSpecifies that the operation should be performed in
non-blocking mode. If the message cannot be queued on the socket, the
zmq_send() function shall fail with errno set to EAGAIN.
ZMQ_SNDMORE
Specifies that the message being sent is a multi-part
message, and that further message parts are to follow. Refer to the section
regarding multi-part messages below for a detailed description.
The zmq_msg_t structure passed to zmq_send() is nullified during
the call. If you want to send the same message to multiple sockets you have to
copy it using (e.g. using zmq_msg_copy()).
Multi-part messages¶
A 0MQ message is composed of 1 or more message parts; each message part is an independent zmq_msg_t in its own right. 0MQ ensures atomic delivery of messages; peers shall receive either all message parts of a message or none at all. The total number of message parts is unlimited. An application wishing to send a multi-part message does so by specifying the ZMQ_SNDMORE flag to zmq_send(). The presence of this flag indicates to 0MQ that the message being sent is a multi-part message and that more message parts are to follow. When the application wishes to send the final message part it does so by calling zmq_send() without the ZMQ_SNDMORE flag; this indicates that no more message parts are to follow.RETURN VALUE¶
The zmq_send() function shall return zero if successful. Otherwise it shall return -1 and set errno to one of the values defined below.ERRORS¶
EAGAINNon-blocking mode was requested and the message cannot be
sent at the moment.
ENOTSUP
The zmq_send() operation is not supported by this
socket type.
EFSM
The zmq_send() 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
zmq_socket(3) for more information.
ETERM
The 0MQ context associated with the specified
socket was terminated.
ENOTSOCK
The provided socket was invalid.
EINTR
The operation was interrupted by delivery of a signal
before the message was sent.
EFAULT
Invalid message.
EXAMPLE¶
Filling in a message and sending it to a socket./* Create a new message, allocating 6 bytes for message content */ zmq_msg_t msg; int rc = zmq_msg_init_size (&msg, 6); assert (rc == 0); /* Fill in message content with 'AAAAAA' */ memset (zmq_msg_data (&msg), 'A', 6); /* Send the message to the socket */ rc = zmq_send (socket, &msg, 0); assert (rc == 0);
/* Send a multi-part message consisting of three parts to socket */ rc = zmq_send (socket, &part1, ZMQ_SNDMORE); rc = zmq_send (socket, &part2, ZMQ_SNDMORE); /* Final part; no more parts to follow */ rc = zmq_send (socket, &part3, 0);
SEE ALSO¶
zmq_recv(3) zmq_socket(7) zmq(7)AUTHORS¶
This manual page was written by the 0MQ community.04/04/2012 | 0MQ 2.2.0 |