【求助】邮箱接收发生问题[已解决]

发布于 2019-03-05 11:38:44 浏览：2198 订阅该版

* 本帖最后由 来日方长 于 2019-3-5 22:08 编辑 *

在线程1中进行邮箱初始化```add_music_mb = rt_mb_create("add_music_mb",10,RT_IPC_FLAG_FIFO);
        if (add_music_mb == RT_NULL)
    {
        rt_kprintf("init mailbox add_music_mb failed.<br>");
        return -RT_ERROR;
    }```线程2中进行发送邮件```result = rt_mb_send(add_music_mb, (rt_ubase_t)newfilemane);```其中newfilemane是一个字符串指针用于存放文件名，指向rt_malloc申请的内存中。发送过在另一个线程里接收```result = rt_mb_recv(add_music_mb,(rt_ubase_t *)addfilemane,RT_WAITING_NO);```addfilemane和newfilemane一样，是char *类型的字符串指针，但是接收时会进入硬件中断，通过单独调试找到的错误发生在rt_mb_recv中，即ipc.c的第1684行```/* increase output offset */
    ++ mb->out_offset;```完整邮箱接收函数如下：```rt_err_t rt_mb_recv(rt_mailbox_t mb, rt_ubase_t *value, rt_int32_t timeout)
{
    struct rt_thread *thread;
    register rt_ubase_t temp;
    rt_uint32_t tick_delta;

/* parameter check */
    RT_ASSERT(mb != RT_NULL);
    RT_ASSERT(rt_object_get_type(&mb->parent.parent) == RT_Object_Class_MailBox);

/* initialize delta tick */
    tick_delta = 0;
    /* get current thread */
    thread = rt_thread_self();

RT_OBJECT_HOOK_CALL(rt_object_trytake_hook, (&(mb->parent.parent)));

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

/* for non-blocking call */
    if (mb->entry == 0 && timeout == 0)
    {
        rt_hw_interrupt_enable(temp);

return -RT_ETIMEOUT;
    }

/* mailbox is empty */
    while (mb->entry == 0)
    {
        /* reset error number in thread */
        thread->error = RT_EOK;

/* no waiting, return timeout */
        if (timeout == 0)
        {
            /* enable interrupt */
            rt_hw_interrupt_enable(temp);

thread->error = -RT_ETIMEOUT;

return -RT_ETIMEOUT;
        }

RT_DEBUG_IN_THREAD_CONTEXT;
        /* suspend current thread */
        rt_ipc_list_suspend(&(mb->parent.suspend_thread),
                            thread,
                            mb->parent.parent.flag);

/* has waiting time, start thread timer */
        if (timeout > 0)
        {
            /* get the start tick of timer */
            tick_delta = rt_tick_get();

RT_DEBUG_LOG(RT_DEBUG_IPC, ("mb_recv: start timer of thread:%s<br>",
                                        thread->name));

/* reset the timeout of thread timer and start it */
            rt_timer_control(&(thread->thread_timer),
                             RT_TIMER_CTRL_SET_TIME,
                             &timeout);
            rt_timer_start(&(thread->thread_timer));
        }

/* enable interrupt */
        rt_hw_interrupt_enable(temp);

/* re-schedule */
        rt_schedule();

/* resume from suspend state */
        if (thread->error != RT_EOK)
        {
            /* return error */
            return thread->error;
        }

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

/* if it's not waiting forever and then re-calculate timeout tick */
        if (timeout > 0)
        {
            tick_delta = rt_tick_get() - tick_delta;
            timeout -= tick_delta;
            if (timeout < 0)
                timeout = 0;
        }
    }

/* fill ptr */
    *value = mb->msg_pool[mb->out_offset];

/* increase output offset */
    ++ mb->out_offset;//这一行会进入硬件中断
    if (mb->out_offset >= mb->size)
        mb->out_offset = 0;
    /* decrease message entry */
    mb->entry --;

/* resume suspended thread */
    if (!rt_list_isempty(&(mb->suspend_sender_thread)))
    {
        rt_ipc_list_resume(&(mb->suspend_sender_thread));

/* enable interrupt */
        rt_hw_interrupt_enable(temp);

RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(mb->parent.parent)));

rt_schedule();

return RT_EOK;
    }

/* enable interrupt */
    rt_hw_interrupt_enable(temp);

RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(mb->parent.parent)));

return RT_EOK;
}
RTM_EXPORT(rt_mb_recv);```目前完全没有头绪，希望大神帮忙看下。

![finsh输出.jpg](https://oss-club.rt-thread.org/uploads/201903/05/113840m6hxpfg1lthqliwf.jpg)