3. Basic functions

3.1 Initialization and main loop

Initializing an Ivy agent with the Ivy-Perl library is done by calling function Ivy::start. In theory, initialization is then over. However in practice, as for any asynchronous communication or interaction library, nothing happens until your application has reached the main loop.

The Ivy Perl library provides two kind of main loop: a "local" loop for perl code, and a "Tk" loop for perl-tk code.

Here is more details on Ivy::start function:

  Ivy::start(-loopMode => 'TK', 
             -ivyBus => '2011', 
             -appName => "TOTO",
             -neededApp => "TITI",
             -statusFunc    => \&statusScan);

MainLoop;

Ivy::stop ();

3.2 Emitting messages

Emitting a message on an Ivy bus is much like printing a message on the standard output. However, do not forget that your message will not be emitted if Ivy has not been properly initialized and if you do not have a main loop of some sort running. To emit a message, use IvySendMsg, which works like printf:

Ivy::sendMsg ("...");

3.3 Subscribing to messages

Subscribing to messages consists in binding a callback function to a message pattern. Patterns are described by regular expressions with captures. When a message matching the regular expression is detected on the bus, the callback function is called. The captures (ie the bits of the message that match the parts of regular expression delimited by brackets) are passed to the callback function much like options are passed to main. Use function Ivy::bindRegexp to bind a callback to a pattern.

Ivy::bindRegexp ("^HELLO WORLD", [\&Start]);

Ivy::bindRegexp ("^HELLO WORLD", NULL);