GTK Help

[WorldDrknss]

I am in the process of learning PHP-GTk and having a problem with buttons.

When I click on a button my app closes instead of echoing out the content.

This is what I have:

 

<?php
if (!class_exists('gtk')) {
dl('php_gtk.' . (strstr(PHP_OS, 'WIN') ? 'dll' : 'so'));
}

$window = new GtkWindow();
$window->set_position(GTK_WIN_POS_CENTER);
$window->set_usize((gdk::screen_width()/2), (gdk::screen_height()/2));
$window->set_title("Some Title");
$window->connect('destroy', array('Gtk','main_quit'));

$hbox = new GtkHBox();


$start_btn = new GtkButton('Start');
$start_btn->connect('clicked', 'server_start');
$hbox->pack_start($start_btn);

$stop_btn = new GtkButton('Stop');
$stop_btn->connect('clicked', 'server_stop');
$hbox->pack_start($stop_btn);

$close_btn = new GtkButton('Close');
$close_btn->connect('clicked', 'app_close');
$hbox->pack_start($close_btn);

function server_start(){
echo "Start\n";
}

function stop_server(){
echo "stop\n";
}

function app_close(){
gtk::main_quit();
}

$window->add($hbox);
$window->show_all(); 
Gtk::main();
?>