The require Function

The require function includes and executes the specified file in the current script. Unlike include, if the file is missing, it causes a fatal error and stops script execution. The function is often used to include important files with functions, classes, or settings.

Syntax

require 'path/to/file.php';

Example

Including a configuration file:

<?php
	require 'config.php';
	echo $db_host; // Variable from config.php
?>

If the config.php file exists, its contents will be executed, and the variables will become available.

Example

Attempting to include a non-existent file:

<?php
	require 'missing_file.php';
	echo 'This line will not execute';
?>

If the missing_file.php file does not exist, the script will terminate with an error.

Difference Between require and include

The main difference is that require causes a fatal error if the file is missing, whereas include only issues a warning.

<?php
	include 'optional_file.php'; // The script will continue to work
	require 'required_file.php'; // The script will stop on error
?>

The require Function

Syntax

Example

Example

Difference Between require and include

See Also