Why aren't php.ini changes working?

Question

I've made some changes to a user's php.ini file, and they are not being reflected. Why are the php.ini settings not working?

Answer

Many PHP directives are classified as PHP_INI_SYSTEM, meaning they can only be configured at the system level via the main php.ini file. Changes made to a user's local php.ini file (such as one in their home directory) will not affect these settings.

To modify PHP_INI_SYSTEM directives, use the MultiPHP INI Editor in the WHM. "WHM / Software / MultiPHP INI Editor"

Additional Resources

MultiPHP INI editor documentation

php.ini directives