# 9. gdb调试器的基本用法

## gdb调试

> 编译链接生成可执行程序，在程序编译链接的过程中注意加上 -g 选项。
>
> ```bash
> gcc -g test.c -o main
> ```
>
> gdb调试生成的可执行程序
>
> ```bash
> gdb main
> ```
>
> ### gdb命令
>
> * 显示源代码
>
>   ```bash
>   l
>   # 或者
>   list
>   ```
>
>   ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMDU3MzQzMA==577930573430)
> * 设置断点
>
>   ```bash
>   b lineNumber
>   # 或者
>   break lineNumber
>   ```
>
>   ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMDY3Mjg0NQ==577930672845)
> * 查看断点信息
>
>   ```bash
>   info break
>   ```
>
>   ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMTE5MzcxMQ==577931193711)
> * 执行程序
>
>   ```bash
>   r
>   # 或者
>   run
>   ```
>
>   ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMTE2NDc1NA==577931164754)
> * 单步执行（两种）
>
>   ```bash
>   n
>   # 或者
>   next
>   ```
>
>   ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMTI3MzMxMg==577931273313)
> * 继续运行
>
>   ```bash
>   c
>   # 或者
>   continue
>   ```
>
>   ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMTUyMDE4MA==577931520180)

* 查看变量值

  ```bash
  p varName
  # 或者
  print varName
  ```

  ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMDg4NDM4NQ==577930884385)
* 修改变量值

  ```bash
  set varName=newValue
  ```

  ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMjQ4MjkwNg==577932482906)
* 查看函数调用堆栈情况

  ```bash
  bt
  ```

  ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMTgzNzg1Mg==577931837852)
* 监控指定变量的值

  ```bash
  watch varName
  ```

  ![图片](http://img.cdn.sugarat.top/mdImg/MTU3Nzk1ODkwNjI1Mg==577958906252)
* 查看寄存器值

  ```bash
  info registers
  ```

  ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMjI3MDU3Mw==577932270573)
* 显示反汇编

  ```bash
  disassemble functionName
  ```

  ![图片](http://img.cdn.sugarat.top/mdImg/MTU3NzkzMjIwNjY0MA==577932206640)
* 运行程序，直到当前函数结束

  ```bash
  finish
  ```
* 退出gdb

  ```bash
  quit
  ```


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