define
(PHP 4, PHP 5, PHP 7)
define — Defines a named constant
Description
bool define ( string $name , mixed $value [, bool $case_insensitive = false ] )Defines a named constant at runtime.
Parameters
name
The 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.
Warning
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.
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
Version | Description |
|---|---|
7.0.0 | array values are allowed. |
Examples
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"
?>See Also
- defined() - Checks whether a given named constant exists
- constant() - Returns the value of a constant
- The section on Constants
← constant
defined →
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