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Manuale PHP
IndietroCapitolo 6. TypesAvanti

NULL

The special NULL value represents that a variable has no value. NULL is the only possible value of type NULL.

Nota: The null type was introduced in PHP 4

A variable is considered to be NULL if

  • it has been assigned the constant NULL.

  • it has not been set to any value yet.

  • it has been unset().

Syntax

There is only one value of type NULL, and that is the case-insensitive keyword NULL.

<?php
$var = NULL;       
?>

See also is_null() and unset().

IndietroPartenzaAvanti
ResourceRisaliPseudo-types used in this documentation
 
 
 
 
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