From the original Amiga UNIX 2.1 manual. Some things it mentions may not be in this release.
NAME
getenv - return value for environment name
SYNOPSIS
#include<stdlib.h>char*getenv(constchar*name);
DESCRIPTION
getenv searches the environment list [see environ(5)] for a string of the form name=value and, if the string is present, returns a pointer to the value in the current environment. Otherwise, it returns a null pointer.