MsgError is executed when there is an error in a message. ParseMessage is executed to get the received messages. Then you must initialize the communications. If you want to execute an application locally on the same host, you give the name of your host. You can also execute the application on a remote host on Internet, see 2.1 .
Every application has a name.
The name of your program has also a name given automatically. Note that the two applications must have been executed first by the preceding message. Note that before being able to exchange messages, applications must have been linked.