int poll(struct pollfd *fds, nfds_t numfds, int timeout)

{

    fd_set read_set;

    fd_set write_set;

    fd_set exception_set;

    nfds_t i;

    int n;

    int rc;



#ifdef __MINGW32__

    if (numfds >= FD_SETSIZE) {

        errno = EINVAL;

        return -1;

    }

#endif



    FD_ZERO(&read_set);

    FD_ZERO(&write_set);

    FD_ZERO(&exception_set);



    n = -1;

    for(i = 0; i < numfds; i++) {

        if (fds[i].fd < 0)

            continue;

#ifndef __MINGW32__

        if (fds[i].fd >= FD_SETSIZE) {

            errno = EINVAL;

            return -1;

        }

#endif



        if (fds[i].events & POLLIN)  FD_SET(fds[i].fd, &read_set);

        if (fds[i].events & POLLOUT) FD_SET(fds[i].fd, &write_set);

        if (fds[i].events & POLLERR) FD_SET(fds[i].fd, &exception_set);



        if (fds[i].fd > n)

            n = fds[i].fd;

    };



    if (n == -1)

        

        return 0;



    if (timeout < 0)

        rc = select(n+1, &read_set, &write_set, &exception_set, NULL);

    else {

        struct timeval    tv;



        tv.tv_sec = timeout / 1000;

        tv.tv_usec = 1000 * (timeout % 1000);

        rc = select(n+1, &read_set, &write_set, &exception_set, &tv);

    };



    if (rc < 0)

        return rc;



    for(i = 0; i < (nfds_t) n; i++) {

        fds[i].revents = 0;



        if (FD_ISSET(fds[i].fd, &read_set))      fds[i].revents |= POLLIN;

        if (FD_ISSET(fds[i].fd, &write_set))     fds[i].revents |= POLLOUT;

        if (FD_ISSET(fds[i].fd, &exception_set)) fds[i].revents |= POLLERR;

    };



    return rc;

}
