Add nng_msg_get_pipe, nng_msg_set_pipe, and nng_pipe_getopt docs.

1 files changed, 56 insertions, 0 deletions

diff --git a/docs/man/nng_msg_get_pipe.adoc b/docs/man/nng_msg_get_pipe.adoc
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+= nng_msg_get_pipe(3)
+//
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This document is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+== NAME
+
+nng_msg_get_pipe - get pipe for message
+
+== SYNOPSIS
+
+[source, c]
+-----------
+#include <nng/nng.h>
+
+nng_pipe nng_msg_get_pipe(nng_msg *msg);
+-----------
+
+== DESCRIPTION
+
+The `nng_msg_get_pipe()` returns the pipe associated with message _msg_.
+On receive, this is the pipe from which a message was received.
+On transmit, this would be the pipe that the message should be delivered
+to, if a specific peer is required.
+
+NOTE: Not all protocols support overriding the destination pipe.
+
+The most usual use case for this is to obtain information about the peer
+from which the message was received.  This can be used to provide different
+behaviors for different peers, such as a higher level of authentication
+for peers located on an untrusted network.
+The <<nng_pipe_getopt#,nng_pipe_getopt(3)>> function is useful in this situation.
+
+
+== RETURN VALUES
+
+This function returns the pipe associated with this message, which will
+be a positive value.  If the pipe is non-positive, then that indicates that
+no specific pipe is associated with the messsage.
+
+== ERRORS
+
+None.
+
+== SEE ALSO
+
+<<nng_msg_alloc#,nng_msg_alloc(3)>>,
+<<nng_msg_set_pipe#,nng_msg_set_pipe(3)>>,
+<<nng_pipe_getopt#,nng_pipe_getopt(3)>>,
+<<nng#,nng(7)>>