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require_once

(PHP 4, PHP 5, PHP 7, PHP 8)

The require_once statement is identical to require except PHP will check if the file has already been included, and if so, not include (require) it again.

See the include_once documentation for information about the _once behaviour, and how it differs from its non _once siblings.

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Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.require-once.php