fd_set x_fds;
FD_ZERO(&x_fds);
FD_SET(x_fd, &x_fds);
struct timeval tv;
tv.tv_sec = 0; tv.tv_usec = 200000;
select(x_fd + 1, &x_fds, 0, 0, &tv);
fd_set x_fds;
FD_ZERO(&x_fds);
FD_SET(x_fd, &x_fds);
struct timeval tv;
tv.tv_sec = 0; tv.tv_usec = 200000;
select(x_fd + 1, &x_fds, 0, 0, &tv);