Method signal

src/bthread/countdown_event.cpp:41–53

}

void CountdownEvent::signal(int sig, bool flush) {
    // Have to save _butex, *this is probably defreferenced by the wait thread
    // which sees fetch_sub
    void* const saved_butex = _butex;
    const int prev = ((butil::atomic<int>*)_butex)
        ->fetch_sub(sig, butil::memory_order_release);
    // DON'T touch *this ever after
    if (prev > sig) {
        return;
    }
    LOG_IF(ERROR, prev < sig) << "Counter is over decreased";
    butex_wake_all(saved_butex, flush);
}

int CountdownEvent::wait() {
    _wait_was_invoked = true;