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diff --git a/doc/zmq_send.txt b/doc/zmq_send.txt new file mode 100644 index 0000000..419e386 --- /dev/null +++ b/doc/zmq_send.txt @@ -0,0 +1,109 @@ +zmq_send(3) +=========== + + +NAME +---- +zmq_send - send a message on a socket + + +SYNOPSIS +-------- +*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_NOBLOCK*:: +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; 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 +------ +*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. +*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 linkzmq:zmq_socket[3] for more information. +*ETERM*:: +The 0MQ 'context' associated with the specified 'socket' was terminated. + + +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); +---- + +.Sending a multi-part message +---- +/* 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 +-------- +linkzmq:zmq_recv[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>. |