xcall CGIUTL, CGIOP_GETENV, envvar, envdef, status

Opcode 5, CGIOP_GETENV, retrieves the contents of the environment variable envvar into the string variable envdef. status will be set to 0 for OK, or 1 if the variable had to be truncated to fit in envdef. If there was no such variable defined, envdef will be null.