выкинь книгу, кури ман.
http://ua.php.net/manual/ru/function.is-bool.php
PHP код:
<?php
$a = false;
$b = 0;
// Since $a is a boolean, this is true
if (is_bool($a)) {
echo "Yes, this is a boolean";
}
// Since $b is not a boolean, this is not true
if (is_bool($b)) {
echo "Yes, this is a boolean";
}
?>