What is the recommended approach for including a library in PHP to avoid constant redefinition errors?

When including a library in PHP, it is recommended to use the `require_once` or `include_once` functions instead of `require` or `include`. This helps to prevent constant redefinition errors that may occur if the library is included multiple times in the same script. By using `require_once` or `include_once`, PHP will only include the library if it has not been included before. 

<?php
require_once 'library.php';

// Your code here
?>

Keywords

PHP library inclusion redefinition errors namespaces autoloading

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