macsock_map_error(kEINVALErr);
PR_IMPLEMENT(struct protoent *) getprotobynumber(int number){    if (number == INET_IP)        return (&sIPProto);            if (number == INET_TCP)        return (&sTCPProto);            if (number == INET_UDP)        return (&sUDPProto);        ErrorExit:    macsock_map_error(kEINVALErr);    return NULL;}