Environment variables
 

For a hack, I would need to read many env vars.
Looking at PhpInfo() and many other sites (almost related to Perl & CGI, but I guess vars are the same...), I saw many many informations php can retrieve from the enviroment.

But I got almost confused when seeing how many containers exist to read those vars.
Well, I would understand where to catch enviroment from php code and exactly which would be the difference between :

• $GLOBALS
• $_ENV
• $HTTP_SERVER_VARS
• $HTTP_SESSION_VARS
• $HTTP_COOKIE_VARS
• getenv()
• ... etc ...

Does someone have any clear idea about ?
Is there any complete reference or manual of all these containers (associative arrays or not...) and when I'd prefer one rather another ?

Thank you very much

Nobody could help me ?
Thnx