mirror of
https://github.com/zeromq/libzmq.git
synced 2024-12-15 03:21:11 +01:00
122 lines
3.7 KiB
Plaintext
122 lines
3.7 KiB
Plaintext
zmq_sendmsg(3)
|
|
==============
|
|
|
|
|
|
NAME
|
|
----
|
|
zmq_sendmsg - send a message part on a socket
|
|
|
|
|
|
SYNOPSIS
|
|
--------
|
|
*int zmq_sendmsg (void '*socket', zmq_msg_t '*msg', int 'flags');*
|
|
|
|
|
|
DESCRIPTION
|
|
-----------
|
|
The _zmq_sendmsg()_ 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_DONTWAIT*::
|
|
Specifies that the operation should be performed in non-blocking mode. If the
|
|
message cannot be queued on the 'socket', the _zmq_sendmsg()_ 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_sendmsg()_ 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()_).
|
|
|
|
NOTE: A successful invocation of _zmq_sendmsg()_ 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. 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 except
|
|
by available memory.
|
|
|
|
An application that sends multipart messages must use the _ZMQ_SNDMORE_ flag
|
|
when sending each data part except the final one.
|
|
|
|
RETURN VALUE
|
|
------------
|
|
The _zmq_sendmsg()_ 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_sendmsg()_ operation is not supported by this socket type.
|
|
*EFSM*::
|
|
The _zmq_sendmsg()_ 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.
|
|
*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.
|
|
*ECANTROUTE*::
|
|
Message cannot be routed to the destination specified as the peer is either
|
|
dead or disconnected. This error makes sense only with ZMQ_ROUTER socket.
|
|
|
|
|
|
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_sendmsg (socket, &msg, 0);
|
|
assert (rc == 6);
|
|
----
|
|
|
|
.Sending a multi-part message
|
|
----
|
|
/* Send a multi-part message consisting of three parts to socket */
|
|
rc = zmq_sendmsg (socket, &part1, ZMQ_SNDMORE);
|
|
rc = zmq_sendmsg (socket, &part2, ZMQ_SNDMORE);
|
|
/* Final part; no more parts to follow */
|
|
rc = zmq_sendmsg (socket, &part3, 0);
|
|
----
|
|
|
|
|
|
SEE ALSO
|
|
--------
|
|
linkzmq:zmq_recv[3]
|
|
linkzmq:zmq_recv[3]
|
|
linkzmq:zmq_recvmsg[3]
|
|
linkzmq:zmq_socket[7]
|
|
linkzmq:zmq[7]
|
|
|
|
|
|
AUTHORS
|
|
-------
|
|
+This man page was written by Martin Sustrik <sustrik@250bpm.com>, Martin
|
|
+Lucina <martin@lucina.net> and Pieter Hintjens <ph@imatix.com>.
|
|
|