1 files changed, 40 insertions, 0 deletions
diff --git a/docs/nspr/reference/prmcastrequest.rst b/docs/nspr/reference/prmcastrequest.rst
new file mode 100644
index 0000000000..9c7c63ecef
--- /dev/null
+++ b/docs/nspr/reference/prmcastrequest.rst
@@ -0,0 +1,40 @@
+PRMcastRequest
+==============
+
+Structure used to specify values for the ``PR_SockOpt_AddMember`` and
+``PR_SockOpt_DropMember`` socket options that define a request to join
+or leave a multicast group.
+
+
+Syntax
+------
+
+.. code::
+
+   #include <prio.h>
+
+   struct PRMcastRequest {
+     PRNetAddr mcaddr;
+     PRNetAddr ifaddr;
+   };
+
+   typedef struct PRMcastRequest PRMcastRequest;
+
+
+Fields
+~~~~~~
+
+The structure has the following fields:
+
+``mcaddr``
+   IP multicast address of group.
+``ifaddr``
+   Local IP address of interface.
+
+
+Description
+-----------
+
+The ``mcaddr`` and ``ifaddr`` fields are of the type :ref:`PRNetAddr`, but
+their ``port`` fields are ignored. Only the IP address (``inet.ip``)
+fields are used.