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Complete PHP Misc Reference
Definition and Usage
The defined() function checks whether a constant exists.
Returns TRUE if the constant exists, or FALSE otherwise.
Syntax
defined(name)
| Parameter | Description |
|---|---|
| name | Required. Specifies the name of the constant to check |
Example
<?php
define("GREETING","Hello you! How are you today?");
echo defined("GREETING");
?>
define("GREETING","Hello you! How are you today?");
echo defined("GREETING");
?>
The output of the code above will be:
1
Complete PHP Misc Reference
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