Function recv_comm

examples/libc/termios_test.c:158–258

}

int recv_comm(int fd, unsigned char *buffer, rt_size_t size, struct timeval *timeout)
{
    struct timeval t;
    int ret = 0;
    rt_size_t drv_recved = 0;
    int recved = 0, need = size;
    int timeout_cnt = 0;
    unsigned char *c = RT_NULL;
    fd_set readSet;

    RT_ASSERT(RT_NULL != buffer);

    if(fd == -1)
    {
        return -1;
    }

    t.tv_sec = 0;
    t.tv_usec = 100000;

    if(RT_NULL == timeout)
    {
        /* Wait forever approximate, it's a large time. */
        timeout_cnt = 0xffffffff;
    }
    else
    {
        timeout_cnt = (timeout->tv_sec * 1000 * 1000 + timeout->tv_usec)/(t.tv_sec * 1000 * 1000 + t.tv_usec);
    }

    while(1)
    {
        FD_ZERO(&readSet);
        FD_SET(fd, &readSet);

        ret = select(fd+1,&readSet,RT_NULL,RT_NULL,&t);
        if(ret < 0)
        {
            rt_kprintf("select error %d\n",ret);
            break;
        }
        else if(ret == 0)
        {
            /* timeout */
            timeout_cnt--;

            if(timeout_cnt == 0)
            {
                rt_kprintf("need %d data in timeout %d ms,but only %d recved.\n",
                            size,
                            timeout->tv_sec * 1000 + timeout->tv_usec / 1000,
                            recved);

                recved = 0;

                break;
            }
        }