environment question

[bob cs csoft net]

In my "begining linux programming" book it says that all the environment
variables are stored like:

#include<stdlib.h>
extern char **environ;

but this is not work.
I need to be able to get a list of all names and values of all environment
variables. How do I do this now? I know about getenv and putenv, but they
arnt any good without knowing the variable names wich I dont.

Thanks,
Bob