Am I using a Production or Development environment in PHP? : How do I configure PHP to either use a production environment or a development environment in PHP 5.5.x?

In order for the errors to display that I want to see, I've uncommented 'Production Value: On' underneath the display_errors section, and 'Production Value: E_ALL & ~E_DEPRECATED & ~E_STRICT' underneath the error_reporting section. However, what determines production vs. development? Is it a setting in php.ini, or somewhere else?