fixes #389 Need pipe notification callbacks

This adds a new pipe event notification API (callbacks called
on either pipe add or remove), including both tests and docs.

Also supporting APIs to get the socket or endpoint associated
with a pipe are included (tested and documented as well.)

1 files changed, 45 insertions, 0 deletions

diff --git a/docs/man/nng_pipe_socket.3.adoc b/docs/man/nng_pipe_socket.3.adoc
new file mode 100644
index 00000000..f2d02aa3
--- /dev/null
+++ b/docs/man/nng_pipe_socket.3.adoc
@@ -0,0 +1,45 @@
+= nng_pipe_socket(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_pipe_socket - return owning socket for pipe
+
+== SYNOPSIS
+
+[source, c]
+----
+#include <nng/nng.h>
+
+nng_socket nng_pipe_socket(nng_pipe p);
+----
+
+== DESCRIPTION
+
+The `nng_pipe_socket()` function returns the `<<nng_socket.5#,nng_socket>>`
+that owns the pipe _p_.
+
+NOTE: The returned socket may be closed or in the process of closing, in
+which case it will not be usable with other functions.
+
+== RETURN VALUES
+
+This function returns the socket that "`owns`" the pipe.
+
+== ERRORS
+
+None.
+
+== SEE ALSO
+
+<<nng_pipe.5#,nng_pipe(5)>>,
+<<nng_socket.5#,nng_socket(5)>>,
+<<nng.7#,nng(7)>>