Function sys_mq_recv

components/lwp/lwp_syscall.c:2798–2824

* @brief Receives a message from a message queue. * * This system call attempts to receive a message from the specified message queue. * The message is copied into the provided buffer. If no message is available * in the queue, the function will block for a specified timeout period before * returning. If the timeout expires without receiving a message, an error is returned. * * @param[in]

 *          blocking, potentially resulting in deadlocks if no message is received.
 */
sysret_t sys_mq_recv(rt_mq_t    mq,
                    void      *buffer,
                    rt_size_t  size,
                    rt_int32_t timeout)
{
    int ret = 0;
    void *kbuffer = RT_NULL;

    if (!lwp_user_accessable((void *)buffer, size))
    {
        return -EFAULT;
    }

    kbuffer = kmem_get(size);
    if (kbuffer == RT_NULL)
    {
        return -ENOMEM;
    }

    ret = rt_mq_recv(mq, kbuffer, size, timeout);
    if (ret > 0)
        lwp_put_to_user((void *)buffer, (void *)kbuffer, ret);

    kmem_put(kbuffer);

    return ret;
}

static void timer_timeout_callback(void *parameter)
{