getenv
Description
string getenv ( string varname)
Returns the value of the environment variable
varname
, or
FALSE
on an error. 

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.
Note: This function does not work in ISAPI mode.
See also putenv().



