require-once in php, phprequire-once_PHP tutorial

require-once in php, phprequire-once

require_once statement and require statement are exactly the same, the only difference is PHP will check whether the file has already been included, and if so, it will not be included again.

See the documentation of include_once to understand the meaning of _once and understand the difference from without _once.

How to use

　define('__ROOT__',dirname(dirname(__FILE__))));
　require_once(__ROOT__.'/config.php');
　?>
Method 2:

2Example: Edit

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require_once('sys/config.php'); require_once('header.php'); ?>   系统平台 一个简单的留言板系统平台 一个简单的留言板。   require_once('footer.php'); ?>

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<🎜>require_once('sys/config.php');<🎜> <🎜>require_once('header.php');<🎜> <🎜>?>

System Platform

A simple message board system platform

A simple message board.

<🎜>require_once('footer.php');<🎜> <🎜>?>

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