Method operator()

src/bvar/default_variables.cpp:385–403

class FdReader {
public:
    bool operator()(int* stat) const {
        if (s_ever_reached_fd_scan_limit.load(butil::memory_order_relaxed)) {
            // Never update the count again.
            return false;
        }
        const int count = get_fd_count(MAX_FD_SCAN_COUNT);
        if (count < 0) {
            return false;
        }
        if (count == MAX_FD_SCAN_COUNT - 2 
                && s_ever_reached_fd_scan_limit.exchange(
                        true, butil::memory_order_relaxed) == false) {
            // Rename the bvar to notify user.
            g_fd_num.hide();
            g_fd_num.expose("process_fd_num_too_many");
        }
        *stat = count;
        return true;
    }
};

static int print_fd_count(void*) {