Method try_lock

thread/thread.cpp:1730–1736

        return waitq_translate_errno(ret);
    }
    int mutex::try_lock()
    {
        thread* ptr = nullptr;
        bool ret = owner.compare_exchange_strong(ptr, CURRENT,
            std::memory_order_acq_rel, std::memory_order_relaxed);
        return (int)ret - 1;
    }
    inline void do_mutex_unlock(mutex* m)
    {
        SCOPED_LOCK(m->splock);