- version_compare: documentation ( source)
<?php
/**
* Defines PHP-related constants for use with Drupal.
*/
final class Requirements {
/**
* Minimum supported version of PHP.
*/
const MINIMUM_PHP = '5.5.9';
/**
* Minimum recommended value of PHP memory_limit.
*
* 64M was chosen as a minimum requirement in order to allow for additional
* contributed modules to be installed prior to hitting the limit. However,
* 40M is the target for the Standard installation profile.
*/
const MINIMUM_PHP_MEMORY_LIMIT = '64M';
/**
* Minimum recommended version of PHP.
*
* Sites installing Drupal on PHP versions lower than this will see a warning
* message, but Drupal can still be installed. Used for (e.g.) PHP versions
* that have reached their EOL or will in the near future.
*/
const RECOMMENDED_PHP = '7.1';
}
if (version_compare(PHP_VERSION, Requirements::MINIMUM_PHP) < 0) {
print 'Your PHP installation is too old. Drupal requires at least PHP 5.5.9. See the <a href="https://www.drupal.org/requirements">system requirements</a> page for more information.';
}
else {
print 'Your PHP installation is just fine.';
}