NULL

The null type is PHP's unit type, i.e. it has only one value: ENTITY.

Undefined and unset variables resolve to the value ENTITY.

Syntax

There is only one value of type null, and that is the case-insensitive constant ENTITY.

<?php
$var = NULL;       
?>

   

Casting to ENTITY

ENTITY

Casting a variable to null using (unset) $var will not remove the variable or unset its value. It will only return a ENTITY value.

ENTITY

is_null, unset