rt-thread自己实现可变长度printf报错

发布于 2021-03-22 19:25:32 浏览：1109 订阅该版

3 个回答

军城Justin 2021-03-22

这家伙很懒，什么也没写！

军城Justin 2021-03-22

这家伙很懒，什么也没写！

军城Justin 2021-03-23

这家伙很懒，什么也没写！

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flashman2002 2021-03-22

这家伙很懒，什么也没写！

可以参考rtt的源码，在kservice.c中：
```
/**
 * This function will print a formatted string on system console
 *
 * @param fmt the format
 */
void rt_kprintf(const char *fmt, ...)
{
    va_list args;
    rt_size_t length;
    static char rt_log_buf[RT_CONSOLEBUF_SIZE];

va_start(args, fmt);
    /* the return value of vsnprintf is the number of bytes that would be
     * written to buffer had if the size of the buffer been sufficiently
     * large excluding the terminating null byte. If the output string
     * would be larger than the rt_log_buf, we have to adjust the output
     * length. */
    length = rt_vsnprintf(rt_log_buf, sizeof(rt_log_buf) - 1, fmt, args);
    if (length > RT_CONSOLEBUF_SIZE - 1)
        length = RT_CONSOLEBUF_SIZE - 1;
#ifdef RT_USING_DEVICE
    if (_console_device == RT_NULL)
    {
        rt_hw_console_output(rt_log_buf);
    }
    else
    {
        rt_uint16_t old_flag = _console_device->open_flag;

_console_device->open_flag |= RT_DEVICE_FLAG_STREAM;
        rt_device_write(_console_device, 0, rt_log_buf, length);
        _console_device->open_flag = old_flag;
    }
#else
    rt_hw_console_output(rt_log_buf);
#endif
    va_end(args);
}
RTM_EXPORT(rt_kprintf);
```