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, 46 insertions, 0 deletions

diff --git a/docs/man/nng_pipe_dialer.3.adoc b/docs/man/nng_pipe_dialer.3.adoc
new file mode 100644
index 00000000..476ab1be
--- /dev/null
+++ b/docs/man/nng_pipe_dialer.3.adoc
@@ -0,0 +1,46 @@
+= nng_pipe_dialer(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_dialer - return dialer that created pipe
+
+== SYNOPSIS
+
+[source, c]
+----
+#include <nng/nng.h>
+
+nng_dialer nng_pipe_dialer(nng_pipe p);
+----
+
+== DESCRIPTION
+
+The `nng_pipe_dialer()` function returns the `<<nng_dialer.5#,nng_dialer>>`
+that created the pipe _p_.
+If the pipe was not created by a dialer, then the returned value will
+have an identifier (`<<nng_dialer_id.3#,nng_dialer_id()>>`) of `-1`.
+
+== RETURN VALUES
+
+This function returns the dialer that created the pipe, unless it was
+not created by a dialer, in which case a value initialized with
+`NNG_DIALER_INITIALIZER` will be returned.
+
+== ERRORS
+
+None.
+
+== SEE ALSO
+
+<<nng_pipe.5#,nng_pipe(5)>>,
+<<nng_dialer.5#,nng_dialer(5)>>,
+<<nng.7#,nng(7)>>