Function cvar_do_wait

thread/thread.cpp:1800–1815

        return ((spinlock*)arg)->lock();
    }
    static int cvar_do_wait(thread_list* q, void* m, Timeout timeout, int(*lock)(void*), void(*unlock)(void*)) {
        assert(m);
        if (!m)
            LOG_ERROR_RETURN(EINVAL, -1, "there must be a lock");
        int ret = thread_usleep_defer(timeout, q, unlock, m);
        auto en = ret < 0 ? errno : 0;
        while (true) {
            int lock_ret = lock(m);
            if (lock_ret == 0) break;
            LOG_ERROR("failed to get mutex lock, ` `, try again", VALUE(ret), ERRNO());
            thread_usleep(1000, nullptr);
        }
        if (ret < 0) errno = en;
        return waitq_translate_errno(ret);

    }
    int condition_variable::wait(mutex* m, Timeout timeout)
    {
        return cvar_do_wait((thread_list*)&q, m, timeout, mutex_lock, mutex_unlock);