#include <sys/epoll.h>
#include <sys/poll.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

int main() {
    int epoll_fd = epoll_create(1);
    struct epoll_event evt;
    struct pollfd pfd;
    fd_set readfd;
    evt.data.fd = 0;
    evt.events = EPOLLIN;
    epoll_ctl(epoll_fd, EPOLL_CTL_ADD, 0, &evt);
    epoll_wait(epoll_fd, &evt, 1, 0);
    FD_ZERO(&readfd);
    FD_SET(epoll_fd, &readfd);
    select(epoll_fd+1, &readfd, NULL, NULL, NULL);
    pfd.fd = epoll_fd;
    pfd.events = POLLIN;
    poll(&pfd, 1, -1);
//    select(epoll_fd+1, NULL, &readfd, NULL, NULL);
//    select(epoll_fd+1, NULL, NULL, &readfd, NULL);
    epoll_wait(epoll_fd, &evt, 1, -1);
}