rt_timer_check的临时链表咨询

发布于 2025-04-01 14:22:57 浏览：43 订阅该版

```c
void rt_timer_check(void)
{
    struct rt_timer *t;
    rt_tick_t current_tick;
    rt_base_t level;
    rt_list_t list;

rt_list_init(&list);

RT_DEBUG_LOG(RT_DEBUG_TIMER, ("timer check enter\n"));

current_tick = rt_tick_get();

/* disable interrupt */
    level = rt_hw_interrupt_disable();

while (!rt_list_isempty(&_timer_list[RT_TIMER_SKIP_LIST_LEVEL - 1]))
    {
        t = rt_list_entry(_timer_list[RT_TIMER_SKIP_LIST_LEVEL - 1].next,
                          struct rt_timer, row[RT_TIMER_SKIP_LIST_LEVEL - 1]);

/*
         * It supposes that the new tick shall less than the half duration of
         * tick max.
         */
        if ((current_tick - t->timeout_tick) < RT_TICK_MAX / 2)
        {
            RT_OBJECT_HOOK_CALL(rt_timer_enter_hook, (t));

/* remove timer from timer list firstly */
            _timer_remove(t);
            if (!(t->parent.flag & RT_TIMER_FLAG_PERIODIC))
            {
                t->parent.flag &= ~RT_TIMER_FLAG_ACTIVATED;
            }
            /* add timer to temporary list  */
            rt_list_insert_after(&list, &(t->row[RT_TIMER_SKIP_LIST_LEVEL - 1]));
            /* call timeout function */
            t->timeout_func(t->parameter);

/* re-get tick */
            current_tick = rt_tick_get();

RT_OBJECT_HOOK_CALL(rt_timer_exit_hook, (t));
            RT_DEBUG_LOG(RT_DEBUG_TIMER, ("current tick: %d\n", current_tick));

/* Check whether the timer object is detached or started again */
            if (rt_list_isempty(&list))
            {
                continue;
            }
            rt_list_remove(&(t->row[RT_TIMER_SKIP_LIST_LEVEL - 1]));
            if ((t->parent.flag & RT_TIMER_FLAG_PERIODIC) &&
                (t->parent.flag & RT_TIMER_FLAG_ACTIVATED))
            {
                /* start it */
                t->parent.flag &= ~RT_TIMER_FLAG_ACTIVATED;
                rt_timer_start(t);
            }
        }
        else break;
    }

/* enable interrupt */
    rt_hw_interrupt_enable(level);

RT_DEBUG_LOG(RT_DEBUG_TIMER, ("timer check leave\n"));
}
```
这里创建这个临时链表的作用是什么?虽然猜测是`t->timeout_func(t->parameter)`会修改正在遍历的链表,但是想不到具体的问题发生的场景.