请问为什么drv_usart.c报错 undefined reference to `rt_hw_serial_isr'

发布于 2022-12-28 11:15:35 浏览：1016 订阅该版

问题现象：

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/03627ac065f6b6cbef4f46e968142b28.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/d88bb9a5e0c9f55e1151c8a3add460c5.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/ea52bd9c3446c00eeb60a2507d87635c.png)

我进行的操作（目的是使用V2版本的串口）：
	使能了串口设备：
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/d5e3a28b14f21e5721b8fe8af4960024.png)
	打开了要用到的串口的宏开关：
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/12a0dc33cd835f338be90529fc1440eb.png)
	将rtdevice.h中的内容修改为：
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/0b6ee4132c1e82ddec4cf7c7bc470db0.png)
	然后我用宏开关的方法注释掉了serial.h和serial.c的全部内容：
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/d512e2c51bd921c9f9955e46e4a51a6c.png)
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/2c99a082548a50b8bdfac1199fdf77a7.png)
	然后编译，然后报错：
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/3fe8796aa1e0e1cf5d746f811897e242.png)

疑问：
	按理说“对某某函数的未定义引用”这样的错误应该是函数原型和声明缺失导致的，但我函数的原型和声明都不缺呀，如下：
	（文件drv_usart.c中的未定义引用部分的rt_hw_serial_isr函数）：
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/43c430d885fea0f901f7658189ac1eca.png)
	（rt_hw_serial_isr函数声明于serial_v2.h，定义于serial_v2.c）：
	
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/a20a3944c25eb82f5fe091f87b62abd8.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/11ecd6ba83796bdedccf9c2054a68631.png)
（drv_usart.c中包含的drv_usart.h文件内容如下）：

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/9694acf68c3ef210e3226675cb1ed7d3.png)

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/2bf6889a26076fa538c3288f2bf0c066.png)

（drv_usart.h中有#include "rtdevice.h"，而rtdevice.h有#include "drivers/serial_v2.h"）：

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20221228/f5006413b0261703af38bbe5788581c0.png)

然后我就不明白了，为什么报错“对某某函数的未定义引用”，明明有声明、有原型呀？