array ( 0 => 'index.php', 1 => 'PHP Manual', ), 'head' => array ( 0 => 'UTF-8', 1 => 'en', ), 'this' => array ( 0 => 'function.is-null.php', 1 => 'is_null', ), 'up' => array ( 0 => 'ref.var.php', 1 => 'Variable handling Functions', ), 'prev' => array ( 0 => 'function.is-long.php', 1 => 'is_long', ), 'next' => array ( 0 => 'function.is-numeric.php', 1 => 'is_numeric', ), 'alternatives' => array ( ), 'source' => array ( 'lang' => 'en', 'path' => 'reference/var/functions/is-null.xml', ), ); $setup["toc"] = $TOC; $setup["toc_deprecated"] = $TOC_DEPRECATED; $setup["parents"] = $PARENTS; manual_setup($setup); ?>
value
The variable being evaluated.
Example #1 is_null() example
<?php
error_reporting(E_ALL);
$foo = NULL;
var_dump(is_null($inexistent), is_null($foo));
?>
Notice: Undefined variable: inexistent in ... bool(true) bool(true)
null
type