Sometimes the callbacks needs access to program data or other information. To
avoid messing with global variables, you can pass the additional data to the
callback when you connect it.
<?php
function on_ok_clicked($button, $window, $my_data) { }
$ok_button->connect('clicked', 'on_ok_clicked', $window, 'some data');
?>
connect() returns an number that uniquely identifies the connection
made. This can be useful if you want to disable or remove the callback during
the execution.
<?php
$conn_id = $ok_button->connect('clicked', 'on_ok_clicked');
$ok_button->signal_handler_block($conn_id); // disable callback
$ok_button->signal_handler_unblock($conn_id); // re-enable callback
$ok_button->disconnect($conn_id); // remove callback permanently
?>
