(PHP 4, PHP 5, PHP 7)
define — Defines a named constant
Defines a named constant at runtime.
nameThe name of the constant.
value
The value of the constant. In PHP 5, value must
be a scalar value (integer,
float, string, boolean, or
NULL). In PHP 7, array values are also accepted.
While it is possible to define resource constants, it is not recommended and may cause unpredictable behavior.
case_insensitive
If set to TRUE, the constant will be defined case-insensitive.
The default behavior is case-sensitive; i.e.
CONSTANT and Constant represent
different values.
Note:
Case-insensitive constants are stored as lower-case.
Returns TRUE on success or FALSE on failure.
Example #1 Defining Constants
<?php
define("CONSTANT", "Hello world.");
echo CONSTANT; // outputs "Hello world."
echo Constant; // outputs "Constant" and issues a notice.
define("GREETING", "Hello you.", true);
echo GREETING; // outputs "Hello you."
echo Greeting; // outputs "Hello you."
// Works as of PHP 7
define('ANIMALS', array(
'dog',
'cat',
'bird'
));
echo ANIMALS[1]; // outputs "cat"
?>