From 4a7aad06d95701cf232198093ce396dcdbb53e5b Mon Sep 17 00:00:00 2001 From: Martin Sustrik Date: Thu, 16 Feb 2012 10:01:47 +0900 Subject: ZeroMQ renamed to Crossroads Signed-off-by: Martin Sustrik --- doc/xs_sendmsg.txt | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 doc/xs_sendmsg.txt (limited to 'doc/xs_sendmsg.txt') diff --git a/doc/xs_sendmsg.txt b/doc/xs_sendmsg.txt new file mode 100644 index 0000000..bf94ecd --- /dev/null +++ b/doc/xs_sendmsg.txt @@ -0,0 +1,121 @@ +xs_sendmsg(3) +============= + + +NAME +---- +xs_sendmsg - send a message part on a socket + + +SYNOPSIS +-------- +*int xs_sendmsg (void '*socket', xs_msg_t '*msg', int 'flags');* + + +DESCRIPTION +----------- +The _xs_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: + +*XS_DONTWAIT*:: +Specifies that the operation should be performed in non-blocking mode. If the +message cannot be queued on the 'socket', the _xs_sendmsg()_ function shall +fail with 'errno' set to EAGAIN. + +*XS_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 _xs_msg_t_ structure passed to _xs_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 _xs_msg_copy()_). + +NOTE: A successful invocation of _xs_sendmsg()_ does not indicate that the +message has been transmitted to the network, only that it has been queued on +the 'socket' and Crossroads have assumed responsibility for the message. + + +Multi-part messages +~~~~~~~~~~~~~~~~~~~ +A Crossroads message is composed of 1 or more message parts. Each message +part is an independent 'xs_msg_t' in its own right. Crossroads ensure 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 _XS_SNDMORE_ flag +when sending each data part except the final one. + +RETURN VALUE +------------ +The _xs_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 _xs_sendmsg()_ operation is not supported by this socket type. +*EFSM*:: +The _xs_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 XS_REP. See the +_messaging patterns_ section of linkxs:xs_socket[3] for more information. +*ETERM*:: +The '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 XS_ROUTER socket. + + +EXAMPLE +------- +.Filling in a message and sending it to a socket +---- +/* Create a new message, allocating 6 bytes for message content */ +xs_msg_t msg; +int rc = xs_msg_init_size (&msg, 6); +assert (rc == 0); +/* Fill in message content with 'AAAAAA' */ +memset (xs_msg_data (&msg), 'A', 6); +/* Send the message to the socket */ +rc = xs_sendmsg (socket, &msg, 0); +assert (rc == 6); +---- + +.Sending a multi-part message +---- +/* Send a multi-part message consisting of three parts to socket */ +rc = xs_sendmsg (socket, &part1, XS_SNDMORE); +rc = xs_sendmsg (socket, &part2, XS_SNDMORE); +/* Final part; no more parts to follow */ +rc = xs_sendmsg (socket, &part3, 0); +---- + + +SEE ALSO +-------- +linkxs:xs_recv[3] +linkxs:xs_recv[3] +linkxs:xs_recvmsg[3] +linkxs:xs_socket[7] +linkxs:xs[7] + + +AUTHORS +------- ++This man page was written by Martin Sustrik , Martin ++Lucina and Pieter Hintjens . + -- cgit v1.2.3