工作代碼片段-epoll

測試的實例：

 int fd =  open("a.txt", 'r'); 
 epoll_event ev; 
 int efd = epoll_create(1); 
 ev.events = EPOLLIN | EPOLLOUT; 
 ev.data.fd = fd; 
 epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ev); 
 epoll_event evs[3]; 
 int r = epoll_wait(efd, evs, 1, 0); 
 if(r == -1) { 
     std::cout << "error" << std::endl; 
 } 
 for(int i =0; i < 1; ++i) { 
     std::cout << " >>>"<< evs[i].data.fd << std::endl; 
     std::cout << "===" << evs[i].events << std::endl; 
     char buff[300]; 
     read(fd, buff, 12); 
     std::cout << buff<< std::endl; 
 } 
 epoll_ctl(efd, EPOLL_CTL_MOD, fd, &ev); 
 
int m = epoll_wait(efd, evs, 1, 0); 
if(m == -1) { 
      std::cout << "error" << std::endl; 
 } 
for(int i =0; i < 1; ++i) { 
    std::cout << " >>>"<< evs[i].data.fd << std::endl; 
    std::cout << "===" << evs[i].events << std::endl; 
} 
close(sfd);