int ret=select (FD_SETSIZE, &active_fd_set, NULL, NULL, timeout_ptr);
// return the timeout we did not use
+ // todo: this is linux specific according to man 2 select
if (usec_timeout > 0 && usec_timeout_remaining != NULL)
*usec_timeout_remaining=(tval.tv_sec*1000000)+tval.tv_usec;