From 4a7aad06d95701cf232198093ce396dcdbb53e5b Mon Sep 17 00:00:00 2001
From: Martin Sustrik <sustrik@250bpm.com>
Date: Thu, 16 Feb 2012 10:01:47 +0900
Subject: ZeroMQ renamed to Crossroads

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
---
 doc/xs_recvmsg.txt | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 doc/xs_recvmsg.txt

(limited to 'doc/xs_recvmsg.txt')

diff --git a/doc/xs_recvmsg.txt b/doc/xs_recvmsg.txt
new file mode 100644
index 0000000..735fed0
--- /dev/null
+++ b/doc/xs_recvmsg.txt
@@ -0,0 +1,121 @@
+xs_recvmsg(3)
+=============
+
+
+NAME
+----
+xs_recvmsg - receive a message part from a socket
+
+
+SYNOPSIS
+--------
+*int xs_recvmsg (void '*socket', xs_msg_t '*msg', int 'flags');*
+
+
+DESCRIPTION
+-----------
+The _xs_recvmsg()_ function shall receive a message part from the socket
+referenced by the 'socket' argument and store it in the message referenced by
+the 'msg' argument. Any content previously stored in 'msg' shall be properly
+deallocated. If there are no message parts available on the specified 'socket'
+the _xs_recvmsg()_ function shall block until the request can be satisfied.
+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 there
+are no messages available on the specified 'socket', the _xs_recvmsg()_
+function shall fail with 'errno' set to EAGAIN.
+
+
+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 processes multipart messages must use the _XS_RCVMORE_
+linkxs:xs_getsockopt[3] option after calling _xs_recvmsg()_ to determine if
+there are further parts to receive.
+
+
+RETURN VALUE
+------------
+The _xs_recvmsg()_ 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 no messages are available at the moment.
+*ENOTSUP*::
+The _xs_recvmsg()_ operation is not supported by this socket type.
+*EFSM*::
+The _xs_recvmsg()_ 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 a message was
+available.
+*EFAULT*::
+The message passed to the function was invalid.
+
+
+EXAMPLE
+-------
+.Receiving a message from a socket
+----
+/* Create an empty message */
+xs_msg_t msg;
+int rc = xs_msg_init (&msg);
+assert (rc == 0);
+/* Block until a message is available to be received from socket */
+rc = xs_recvmsg (socket, &msg, 0);
+assert (rc != -1);
+/* Release message */
+xs_msg_close (&msg);
+----
+
+.Receiving a multi-part message
+----
+int64_t more;
+size_t more_size = sizeof more;
+do {
+    /* Create an empty message to hold the message part */
+    xs_msg_t part;
+    int rc = xs_msg_init (&part);
+    assert (rc == 0);
+    /* Block until a message is available to be received from socket */
+    rc = xs_recvmsg (socket, &part, 0);
+    assert (rc != -1);
+    /* Determine if more message parts are to follow */
+    rc = xs_getsockopt (socket, XS_RCVMORE, &more, &more_size);
+    assert (rc == 0);
+    xs_msg_close (&part);
+} while (more);
+----
+
+
+SEE ALSO
+--------
+linkxs:xs_recv[3]
+linkxs:xs_send[3]
+linkxs:xs_sendmsg[3]
+linkxs:xs_getsockopt[3]
+linkxs:xs_socket[7]
+linkxs:xs[7]
+
+
+AUTHORS
+-------
+This man page was written by Martin Sustrik <sustrik@250bpm.com>, Martin
+Lucina <martin@lucina.net> and Pieter Hintjens <ph@imatix.com>.
+
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