- * This function returns immediately if not invoked with EUID zero. Otherwise,
- * it tries to obtain the UID for the user specified by \a username and exits
- * if this user was not found. On success, effective and real UID and the saved
- * set-user-ID are all set to the UID of \a username.
+ * This function returns immediately if not invoked with EUID zero. Otherwise,
+ * it tries to obtain the GID of \a groupname and the UID of \a username. On
+ * success, effective and real GID/UID and the saved set-group-ID/set-user-ID
+ * are all set accordingly. On errors, an appropriate message is logged and exit()
+ * is called to terminate the process.