You are browsing the Symfony 4.1 documentation, which changes significantly from Symfony 3.x. If your app doesn't use Symfony 4.1 yet, browse the Symfony 3.4 documentation.
The Symfony Polyfill / PHP 7.3 Component
The Symfony Polyfill / PHP 7.3 Component¶
This component provides some PHP 7.3 features to applications using earlier PHP versions.
$ composer require symfony/polyfill-php73
Alternatively, you can clone the https://github.com/symfony/polyfill-php73 repository.
If you install this component outside of a Symfony application, you must
vendor/autoload.php file in your code to enable the class
autoloading mechanism provided by Composer. Read
this article for more details.
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.