Function fd_close

src/bthread/fd.cpp:278–312

    }

    int fd_close(int fd) {
        if (fd < 0) {
            // what close(-1) returns
            errno = EBADF;
            return -1;
        }
        butil::atomic<EpollButex*>* pbutex = bthread::fd_butexes.get(fd);
        if (NULL == pbutex) {
            // Did not call bthread_fd functions, close directly.
            return close(fd);
        }
        EpollButex* butex = pbutex->exchange(
            CLOSING_GUARD, butil::memory_order_relaxed);
        if (butex == CLOSING_GUARD) {
            // concurrent double close detected.
            errno = EBADF;
            return -1;
        }
        if (butex != NULL) {
            butex->fetch_add(1, butil::memory_order_relaxed);
            butex_wake_all(butex);
        }
#if defined(OS_LINUX)
        epoll_ctl(_epfd, EPOLL_CTL_DEL, fd, NULL);
#elif defined(OS_MACOSX)
        struct kevent evt;
        EV_SET(&evt, fd, EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
        kevent(_epfd, &evt, 1, NULL, 0, NULL);
        EV_SET(&evt, fd, EVFILT_READ, EV_DELETE, 0, 0, NULL);
        kevent(_epfd, &evt, 1, NULL, 0, NULL);
#endif
        const int rc = close(fd);
        pbutex->exchange(butex, butil::memory_order_relaxed);
        return rc;
    }

    bool started() const {
        return _epfd >= 0;