GDB 常用命令一览
目录
命令
GDB 是 Linux 下的命令行调试工具。
启动 GDB 有如下几种方式：
gdb <program>直接启动执行程序gdb <program> core用gdb 同时调试一个可执行程序和core文件。core 是程序非法执行后 core dump 产生的文件gdb <program> <PID>指定进程， gdb会自动 attach 上去。program 应该在 PATH 环境变量中可以搜索得到。
常用的 gdb 命令如下
信息 info
info 可以简写成 i
info args列出参数info breakpointsinfo breaki b列出所有断点info break numberi b number列出序号为 number 的的断点info watchpointsi watchpoints列出所在 watchpointsinfo threads列出所有线程inifo registers列出寄存器的值info set列出当前 gdb的所的设置i framei stacki localsi catch
断点和监视 break & watch
break 可以简写为 b
break fun_nameb fun_name在 fun_name 处打断点b line_number在 line_number 处打断点b +offset在offset 行后加断点b -offset同上b file_name:fun_name文件的方法名处打断点b fine_name:line_number同上b *address在某地址处打断点。适用于没有源码的情况b line_number if condition条件断点。当条件为 true 时会中断tbreaktb单次命中断点。如tb 12表示只会在第12行命中一次。
watch 可以添加监视。watch 没有简写watch var监视var变量watch condition带条件的监视。如watch a>1
删除和禁用断点
clear清除当前行的断点clear fun_name清除 fun_name 中的所有断点clear line_number删除该行的断点delete简写d. 删除所有的 breakpoints, watchpoints, or catchpoints.d num删除序号为 num 的断点d num1-num2删除序号从 num1 到 num2 的所有断点disable/enable num禁用/启用序号为 num 的断点disable/enable num1-num2禁用/启用 序号从 num1到 num2 的断点
调试
run简写r运行程序step简写s单步，可以进入方法（相当于 VS 的 F11）finish跳出当前方法(相当于VS 的 sh+F11)next简写n单步，不会进入方法（相当于 VS 的 F10）until line-number运行到 line-number 行。line-number 只能比当前行数大。 until 还可以接 function name, address, filename:function or filename:line-numberwhere显示当前行数和方法backtrace简写bt显示当前的栈信息bt full打印完整的栈信息frame简写f显示当前栈的 frame 信息f number选择frameup / down / up number /down number选择 frame
源码
list简写l列出源码l num列出 num 行前后的源码l fun列出方法 fun 的源码l start_num, end_numl file_name:fun_nameset listsize count设置一次显示多少行源码(默认为10)show listsize显示listsizedirectiory dir_name简写dir dir_name, 将指定的目录加入源码文件的前缀show diri line显示l所指的行(注意不是当前行)在obj中的起始地址i line line_number同上stepisi汇编级调试nextini
变量
print var简写p var打印变量varp file_name:varp/x var以16进制打印整型变量 。p/d var10进制p/u varunsigned intp/o var8进制p/t var2进制 (1byte/8bits)p/c var以字符形式p/f var以 floating 形式p/a var以十六进制地址x/4b &var以 4 byte 打印var 的内存ptype var显示var 的类型ptype date-type显示原类型
启动
run简写rcontinue简写ckill杀掉当前调试的程序quit简写q退出gdb
实践
源码：
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#include <iostream> using namespace std; int fun_add(int a,int b){ int s = a+b; return s; } int main(){ int a = 0; cout<<a<<endl; cout<<a++<<endl; cout<<++a<<endl; int x = fun_add(a, 2); cout<<x<<endl; while(a < 10){ a++; } return 0; } |
编译：
> g++ -g ./test.c -o test
调试：
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zr@zr:~/code/use_gdb/src1$ gdb ./test <----- 启动调试 GNU gdb (Ubuntu 8.1-0ubuntu3.1) 8.1.0.20180409-git Copyright (C) 2018 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> 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-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from ./test...done. (gdb) l <----- 列出源码 1 #include <iostream> 2 3 using namespace std; 4 5 int fun_add(int a,int b){ 6 int s = a+b; 7 return s; 8 } 9 10 int main(){ (gdb) <----- 回车，进行上一次操作 11 int a = 0; 12 cout<<a<<endl; 13 cout<<a++<<endl; 14 cout<<++a<<endl; 15 16 int x = fun_add(a, 2); 17 cout<<x<<endl; 18 19 while(a < 10){ 20 a++; (gdb) b 12 <----- 第12行打断点 Breakpoint 1 at 0x8b3: file ./test.c, line 12. (gdb) b 16 <----- 第16行打断点 Breakpoint 2 at 0x92f: file ./test.c, line 16. (gdb) l fun_add <----- 查看 fun_add 所在的行 1 #include <iostream> 2 3 using namespace std; 4 5 int fun_add(int a,int b){ 6 int s = a+b; 7 return s; 8 } 9 10 int main(){ (gdb) b fun_add <----- 方法 fun_add 打断点 Breakpoint 3 at 0x894: file ./test.c, line 6. (gdb) r <----- 启动程序。将在第一个断点外中断 Starting program: /home/zr/code/use_gdb/src1/test Breakpoint 1, main () at ./test.c:12 12 cout<<a<<endl; (gdb) p a <----- 打印变量 a $1 = 0 (gdb) n <----- 执行下一行 0 13 cout<<a++<<endl; (gdb) p a $2 = 0 (gdb) n 0 14 cout<<++a<<endl; (gdb) p a $3 = 1 (gdb) watch a <----- 监视变量 a Hardware watchpoint 4: a (gdb) n Hardware watchpoint 4: a Old value = 1 New value = 2 0x0000555555554909 in main () at ./test.c:14 14 cout<<++a<<endl; (gdb) i b <----- 查看所有断点 Num Type Disp Enb Address What 1 breakpoint keep y 0x00005555555548b3 in main() at ./test.c:12 breakpoint already hit 1 time 2 breakpoint keep y 0x000055555555492f in main() at ./test.c:16 3 breakpoint keep y 0x0000555555554894 in fun_add(int, int) at ./test.c:6 4 hw watchpoint keep y a breakpoint already hit 1 time (gdb) watch a>5 <----- 添加条件监视 Hardware watchpoint 5: a>5 (gdb) i b <----- 查看所有断点 Num Type Disp Enb Address What 1 breakpoint keep y 0x00005555555548b3 in main() at ./test.c:12 breakpoint already hit 1 time 2 breakpoint keep y 0x000055555555492f in main() at ./test.c:16 3 breakpoint keep y 0x0000555555554894 in fun_add(int, int) at ./test.c:6 4 hw watchpoint keep y a breakpoint already hit 1 time 5 hw watchpoint keep y a>5 (gdb) c <----- continue Continuing. 2 Breakpoint 2, main () at ./test.c:16 16 int x = fun_add(a, 2); (gdb) i args <----- 命中断点后查看所有参数 No arguments. (gdb) n Breakpoint 3, fun_add (a=2, b=2) at ./test.c:6 6 int s = a+b; (gdb) i args <----- 查看所有参数 a = 2 b = 2 (gdb) p/t a <----- 以二进制查看变量a $4 = 10 (gdb) finish <----- 跳出当前方法 Run till exit from #0 fun_add (a=2, b=2) at ./test.c:6 0x000055555555493e in main () at ./test.c:16 16 int x = fun_add(a, 2); Value returned is $5 = 4 (gdb) where #0 0x000055555555493e in main () at ./test.c:16 (gdb) n 17 cout<<x<<endl; (gdb) c <----- continue 直到命中断点或监视的变量有了变化 Continuing. 4 Hardware watchpoint 4: a Old value = 2 New value = 3 main () at ./test.c:19 19 while(a < 10){ (gdb) i b Num Type Disp Enb Address What 1 breakpoint keep y 0x00005555555548b3 in main() at ./test.c:12 breakpoint already hit 1 time 2 breakpoint keep y 0x000055555555492f in main() at ./test.c:16 breakpoint already hit 1 time 3 breakpoint keep y 0x0000555555554894 in fun_add(int, int) at ./test.c:6 breakpoint already hit 1 time 4 hw watchpoint keep y a breakpoint already hit 2 times 5 hw watchpoint keep y a>5 (gdb) c Continuing. Hardware watchpoint 4: a Old value = 4 New value = 5 main () at ./test.c:19 19 while(a < 10){ (gdb) c Continuing. Hardware watchpoint 4: a Old value = 6 New value = 7 main () at ./test.c:19 19 while(a < 10){ (gdb) disable 4 <----- 取消断点/监视 4 (gdb) c Continuing. |