updated README.

1 files changed, 44 insertions, 0 deletions

diff --git a/cpp/demo/IceStorm/clock/README b/cpp/demo/IceStorm/clock/README
index 53705ff60fa..dc7f8affcd7 100644
--- a/cpp/demo/IceStorm/clock/README
+++ b/cpp/demo/IceStorm/clock/README
@@ -17,3 +17,47 @@ $ publisher
 
 While the publisher continues to run "tick" messages should be
 displayed in the subscriber window.
+
+Both the subscriber and publisher take an optional topic name as a
+final argument. This default value for the topic is "time".
+
+Through the use of command line options both the subscriber and
+publisher can use different QoS for sending and receiving messages.
+
+For the subscriber:
+
+subscriber --oneway
+
+The subscriber receives the events as oneway messages. This is the default.
+
+subscriber --datagram
+
+The subscriber receives events as datagrams.
+
+subscriber --twoway
+
+The subscriber receives events as twoway messages.
+
+subscriber --ordered
+
+The subscriber receives the events as twoway messages with guaranteed
+ordering.
+
+subscriber --batch
+
+This is an additional flag which forces the subscriber to receive
+datagram and oneway events as batches.
+
+For the publisher:
+
+publisher --oneway
+
+The publisher sends events as oneway messages. This is the default.
+
+publisher --datagram
+
+The publisher sends events as datagrams.
+
+publisher --twoway
+
+The publisher sends events as twoway messages.