NAME

       zmq_send - send a message part on a socket

SYNOPSIS

       int zmq_send (void *socket, void *buf, size_t len, int flags);

DESCRIPTION

       The zmq_send() function shall queue a message created from the buffer referenced by the buf and len
       arguments. The flags argument is a combination of the flags defined below:

       ZMQ_DONTWAIT
           For socket types (DEALER, PUSH) that block when there are no available peers (or all peers have full
           high-water mark), specifies 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.

           Note
           A successful invocation of zmq_send() does not indicate that the message has been transmitted to the
           network, only that it has been queued on the socket and 0MQ has assumed responsibility for the
           message.

   Multi-part messages
       A 0MQ message is composed of 1 or more message parts. 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 except by available memory.

       An application that sends multi-part messages must use the ZMQ_SNDMORE flag when sending each message
       part except the final one.

RETURN VALUE

       The zmq_send() function shall return number of bytes in the message 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 the message cannot be sent at the moment.

       ENOTSUP
           The zmq_send() operation is not supported by this socket type.

       EINVAL
           The sender tried to send multipart data, which the socket type does not allow.

       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.

       EHOSTUNREACH
           The message cannot be routed.

EXAMPLE

       Sending a multi-part message.

           /* Send a multi-part message consisting of three parts to socket */
           rc = zmq_send (socket, "ABC", 3, ZMQ_SNDMORE);
           assert (rc == 3);
           rc = zmq_send (socket, "DEFGH", 5, ZMQ_SNDMORE);
           assert (rc == 5);
           /* Final part; no more parts to follow */
           rc = zmq_send (socket, "JK", 2, 0);
           assert (rc == 2);

SEE ALSO

       zmq_send_const(3) zmq_recv(3) zmq_socket(7) zmq(7)

AUTHORS

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       http://www.zeromq.org/docs:contributing.