Solution to empty $ _ env in PHP

In PHP, $ _ env stores some system environment variables, which have different values due to different environments.
However, sometimes $ _ env is empty for the following reasons:
In PHP. the variables_order value in INI is "GPCs", that is, the system defines the order of PHP predefined variables as get, post, cookies, server, and Environment (e ), you can modify PHP. the variables_order value of the INI file, for example, "egpcs ". Then, the value of $ _ env can be obtained.
Egpcs (egpcs are short for Environment, get, post, cookies, and server. This is the full range of external variable sources in PHP ).