PHP define() Function
Example
Define a case-sensitive constant:
<?php
define("GREETING","Hello you! How are you today?");
echo constant("GREETING");
?>
Try it Yourself »
Definition and Usage
The define() function defines a constant.
Constants are much like variables, except for the following differences:
- A constant's value cannot be changed after it is set
- Constant names do not need a leading dollar sign ($)
- Constants can be accessed regardless of scope
- Constant values can only be strings and numbers
Syntax
define(name,value,case_insensitive)
Parameter Values
| Parameter | Description |
|---|---|
| name | Required. Specifies the name of the constant |
| value | Required. Specifies the value of the constant. |
| case_insensitive | Optional. Specifies whether the constant name should be case-insensitive. Possible values:
|
Technical Details
| Return Value: | Returns TRUE on success or FALSE on failure |
|---|---|
| PHP Version: | 4+ |
| Changelog: | PHP 7.3: Defining case-insensitive constants is deprecated. PHP 7: The value parameter can also be an array. PHP 5: The value parameter must be a string, integer, float, boolean or NULL. |
❮ PHP Misc Reference
