getenv

(PHP 3, PHP 4 , PHP 5)

getenv -- Gets the value of an environment variable

Description

string getenv ( string varname)

Returns the value of the environment variable varname, or FALSE on an error.

<?php
$ip
= getenv("REMOTE_ADDR"); // get the ip number of the user
?>

You can see a list of all the environmental variables by using phpinfo(). You can find out what many of them mean by taking a look at the CGI specification, specifically the page on environmental variables.

See also putenv().