Linux中的GDB调试器

在编译时如果我们仅仅依靠gcc发出的警告或错误信息来进行修改，调试的效率非常低，也不容易发现错误的所在。为此，GNU开发了GDB调试器。

下面我们就来简单认识一下GDB调试器:



[root@promote 1118]# gcc -g 14.c -o 14

[root@promote 1118]# gdb 14

GNU gdb Red Hat Linux (6.5-25.el5rh)

Copyright (C) 2006 Free Software Foundation, Inc.

GDB is free software, covered by the GNU General Public License, and you are

welcome to change it and/or distribute copies of it under certain conditions.

Type “show copying” to see the conditions.

There is absolutely no warranty for GDB. Type “show w
4000
arranty” for details.

This GDB was configured as “i386-redhat-linux-gnu”…Using host libthread_db library “/lib/libthread_db.so.1”.

(gdb) l

10 int cal(int n)

11 {

12 if(n == 1)

13 return 1;

14 else

15 return n * cal(n - 1);

16 }

17 int main(int argc, char **argv)

18 {

19 int n = 5;

(gdb) b 15

Breakpoint 1 at 0x8048399: file 14.c, line 15.

(gdb) r

Starting program: /tjy/C语言/1118/14

Breakpoint 1, cal (n=5) at 14.c:15

15 return n * cal(n - 1);

(gdb) p n

$1 = 5

(gdb) c

Continuing.

Breakpoint 1, cal (n=4) at 14.c:15

15 return n * cal(n - 1);

(gdb) p n

$2 = 4

(gdb) n

Breakpoint 1, cal (n=3) at 14.c:15

15 return n * cal(n - 1);

(gdb) n

Breakpoint 1, cal (n=2) at 14.c:15

15 return n * cal(n - 1);

(gdb) s

cal (n=1) at 14.c:12

12 if(n == 1)

(gdb) s

13 return 1;

(gdb) q

The program is running. Exit anyway? (y or n) y

[root@promote 1118]#

这就是GDB调试器的运行过程。

主要的几个操作如下：

1.gcc -g 15.c -o 15:把调试信息加入到可执行文件中

2.gdb 15:启动GDB进行调试

3.gdb l:查看所有的代码行数

4.gdb b 15:设置断点

5.gdb info b:查看断点情况

6.gdb r:运行程序，在断点前一行暂停

7:gdb p n:查看变量值

8.gdb c:继续运行程序

9:gdb s:让程序一步一步的往下运行