为何要允许EPOLL_CTL_DEL的失败？

[xb1520]

大佬们，我想问一下，为什么要允许EPOLL_CTL_DEL的失败？EPOLL_CTL_DEL在何时会失败呢？
在muduo/net/poller/EPollPoller.cc的183行，当操作为EPOLL_CTL_DEL时使用LOG_SYSERR 打印日志，不会调用abort。
提交id是ab9c82a，提交信息是allow error at EPOLL_CTL_DEL
源代码如下:

void EPollPoller::update(int operation, Channel* channel)
{
  struct epoll_event event;
  memZero(&event, sizeof event);
  event.events = channel->events();
  event.data.ptr = channel;
  int fd = channel->fd();
  LOG_TRACE << "epoll_ctl op = " << operationToString(operation)
    << " fd = " << fd << " event = { " << channel->eventsToString() << " }";
  if (::epoll_ctl(epollfd_, operation, fd, &event) < 0)
  {
    if (operation == EPOLL_CTL_DEL)
    {
      LOG_SYSERR << "epoll_ctl op =" << operationToString(operation) << " fd =" << fd;
    }
    else
    {
      LOG_SYSFATAL << "epoll_ctl op =" << operationToString(operation) << " fd =" << fd;
    }
  }
}

[chenshuo]

在你提到的这个 commit 之前，是 66ec601 add curl example.

因为 curl 会自己先 close fd，再通知我们不再关注其上的 event，所以会出现 EPOLL_CTL_DEL 错误。

为此只能不把 EPOLL_CTL_DEL 当致命错误。

[xb1520]

嗷嗷，谢谢大佬解答