You are browsing the Symfony 4 documentation, which changes significantly from Symfony 3.x. If your app doesn't use Symfony 4 yet, browse the Symfony 3.4 documentation.
The Symfony Polyfill / PHP 7.2 Component
The Symfony Polyfill / PHP 7.2 Component¶
This component provides some PHP 7.2 features to applications using earlier PHP versions.
$ composer require symfony/polyfill-php72
Alternatively, you can clone the https://github.com/symfony/polyfill-php72 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.
Once this component is installed in your application, you can use the following constants and functions, no matter if your PHP version is earlier than PHP 7.2.
PHP_OS_FAMILY(value = depends on your operating system)
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.