PHP server environment variable $ _ ENV

 

 

PHP $ _ ENV variable

$ _ ENV is an array containing server environment variables. It is a super global variable in PHP. We can directly access it anywhere in the PHP program.

$ _ ENV only passively accepts server-side environment variables and converts them into array elements. You can print them directly:

Print_r ($ _ ENV );

The printed results are not listed here, and the printed results may be completely different on different servers.

$ _ ENV array elements

Elements (array units) in the $ _ ENV array vary greatly with the SERVER environment, so they cannot list the complete list as $ _ SERVER does. The following are more common elements contained in the $ _ ENV array:

$ _ SERVER ['path']: PATH of the environment variable.

$ _ SERVER ['classpath']: System CLASSPATH path.

$ _ SERVER ['lib']: System LIB library path.

$ _ SERVER ['include ']: system INCLUDE path. Note that it is different from PHP's Include path.

$ _ SERVER ['OS']: operating system type.

$ _ SERVER ['lang ']: system language, such as en_US or zh_CN.

$ _ SERVER ['pwd']: current working directory.

$ _ SERVER ['temp ']: System TEMP path.

$ _ SERVER ['ap _ PARENT_PID ']: ID of the current process.

$ _ SERVER ['Number _ OF_PROCESSORS ']: NUMBER of system CPUs.

$ _ Causes and solutions for null ENV

If the output $ _ ENV is empty, check the configuration of php. ini:

Variables_order = "EGPCS"

The above configuration indicates the sources and sequence of external variables accepted by PHP. EGPCS are short for Environment, Get, Post, Cookies, and Server. If E is missing in the configuration of variables_order, PHP cannot accept environment variables, and $ _ ENV is empty.

Address: http://www.5idev.com/p-php_env.shtml