SendMessage(port$, cmd$[, ...])
cmd$ to the message port
specified in port$. The command specified in cmd$ must not contain any
space characters. Additionally, you can send an unlimited number of
arguments to the message port. Just pass them as optional arguments
after the command name. The optional arguments must be passed as strings.
The port specified in port$ must have been created previously by a
call to CreatePort(). Please remember that port names
are case sensitive, i.e. "MYPORT" and "myport" denote two different message
ports. For style guide reasons, port names are usually in upper case only.
The message will be sent to the specified message port in form of a
OnUserMessage event that will be forwarded to the callback you
specified when installing this event handler using InstallEventHandler().