1.此文档演示如何使用gdb调试c语言代码。

代码如下:

#include 
        
         /*函数声明*/void digui(int n);int main(){  int n=10;  digui(n);  return 0;}void digui(int n){  printf("level1-value of %d\n",n);  if(n>2){    digui(n-1);  }   printf("level2-value of %d\n",n);}
        

2.编译debug模式下的程序，编译方式如下:

[zsd@TOMCAT ~]$ gcc -g test03.c -o test03debug

3.进入gdb的debug模式，如下：

[zsd@TOMCAT ~]$ gdb test03debug GNU gdb (GDB) Red Hat Enterprise Linux (7.2-60.el6_4.1)Copyright (C) 2010 Free Software Foundation, Inc.License GPLv3+: GNU GPL version 3 or later 
        
         This is free software: you are free to change and redistribute it.There is NO WARRANTY, to the extent permitted by law.  Type "show copying"and "show warranty" for details.This GDB was configured as "x86_64-redhat-linux-gnu".For bug reporting instructions, please see:
         ...Reading symbols from /home/zsd/test03debug...done.(gdb)
        

4.gdb模式下，list命令，查看源代码:

(gdb) list1       #include 
        
         2       /*函数声明*/3       void digui(int n);45       int main()6       {7         int n=10;8         digui(n);9         return 0;10      }(gdb) 1112      void digui(int n)13      {14        printf("level1-value of %d\n",n);15        if(n>2){16          digui(n-1);17        } 18        printf("level2-value of %d\n",n);19      }20
        

5.list的相关命令，如下:

(gdb) set listsize 30   //设置显示行数(gdb) show listsize;   //查看显示行数Number of source lines gdb will list by default is 30.(gdb) list 1,20          //显示1~20行的源代码1       #include 
        
         2       /*函数声明*/3       void digui(int n);45       int main()6       {7         int n=10;8         digui(n);9         return 0;10      }1112      void digui(int n)13      {14        printf("level1-value of %d\n",n);15        if(n>2){16          digui(n-1);17        } 18        printf("level2-value of %d\n",n);19      }20
        

6.设置断点。

个人思路:由于希望研究递归函数的过程，所以对目前程序的16行和18行，设置断点。操作如下:

(gdb) break 16    //设置16行的断点Breakpoint 1 at 0x40050c: file test03.c, line 16.(gdb) break 18    //设置18行的断点Breakpoint 2 at 0x400519: file test03.c, line 18.(gdb) info breakpoints   //查看断点信息Num     Type           Disp Enb Address            What1       breakpoint     keep y   0x000000000040050c in digui at test03.c:162       breakpoint     keep y   0x0000000000400519 in digui at test03.c:18 删除断点的命令:(这里不执行，只是告知断点的方式)

(gdb) clear 16 (gdb) clear 18

7.开始调试程序

(gdb) run        //开始执行调试程序Starting program: /home/zsd/test03debug level1-value of 10Breakpoint 1, digui (n=10) at test03.c:1616          digui(n-1);       //停止到设置在第一个断点，程序在第16行暂停。Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.132.el6.x86_64(gdb) contiune              //continue命令，是在碰到断点的情况下，停止Undefined command: "contiune".  Try "help".(gdb) continueContinuing.level1-value of 9     Breakpoint 1, digui (n=9) at test03.c:1616          digui(n-1);      //第二次碰到断点，程序停止，依次递推(gdb) continueContinuing.level1-value of 8Breakpoint 1, digui (n=8) at test03.c:1616          digui(n-1);(gdb) continueContinuing.level1-value of 7Breakpoint 1, digui (n=7) at test03.c:1616          digui(n-1);(gdb) continueContinuing.level1-value of 6Breakpoint 1, digui (n=6) at test03.c:1616          digui(n-1);(gdb) continueContinuing.level1-value of 5Breakpoint 1, digui (n=5) at test03.c:1616          digui(n-1);(gdb) continueContinuing.level1-value of 4Breakpoint 1, digui (n=4) at test03.c:1616          digui(n-1);(gdb) continueContinuing.level1-value of 3Breakpoint 1, digui (n=3) at test03.c:1616          digui(n-1);(gdb) continueContinuing.level1-value of 2Breakpoint 2, digui (n=2) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 2Breakpoint 2, digui (n=3) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 3Breakpoint 2, digui (n=4) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 4Breakpoint 2, digui (n=5) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 5Breakpoint 2, digui (n=6) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 6Breakpoint 2, digui (n=7) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 7Breakpoint 2, digui (n=8) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 8Breakpoint 2, digui (n=9) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 9Breakpoint 2, digui (n=10) at test03.c:1818        printf("level2-value of %d\n",n);(gdb) continueContinuing.level2-value of 10Program exited normally.

run，开始运行程序；

continue，程序暂停时继续运行程序的命令；

print 变量名或表达式，打印该变量或者该表达式的值。whatis 变量名或者表达式，可以显示该变量或表达式的数据类型。

print  变量=值，这种形式还可以给对应的变量赋值；类似的还有set variable 变量=值。作用和用print赋值相同。

next，继续执行下一条语句；还有一条命令step，与之类似，不同的是，当下一条语句遇到函数调用的时候，next不会跟踪进入函数，而是继续执行下面的语句，而step命令则会跟踪进入函数内部。