The reason why PHP $_env is empty _php tips

But some friends of the $_env is empty, may be the reason is:
The Variables_order value of your php.ini is "gpcs", which means that the order in which the system defines PHP predefined variables is get,post,cookies,server, and no Environment (E) is defined. You can modify the Variables_order value of the php.ini file for the order you want, such as "Egpcs". At this point, the value of the $_env can be achieved

Egpcs value (Egpcs is the abbreviation for environment, GET, Post, Cookies, server-This is the entire range of external variable sources in PHP)