The `MsgPort Basename' is the default base name for any opened arexx message port of the application. The generated functions automatically append some incrementing number to this name until a port can be opened without conflict.
The application should provide (as shown in the demo code) an argument or tooltype named ``PORTNAME'', so the user can set the base name to something else. The new portname will be handled exactly the same way (see sample code).
Additionally, `MsgPort Basename' is used to identify the ARexx scripts belonging to that application: It becomes the default file extension for the application's ARexx programs.