GDB "jump" 命令没有跳转到有效上下文？

Question

我希望跳转到相同上下文或函数外部的一行。我有一个 "test.c"

  1 
  2 #include<stdio.h>
  3 void fa(int c)
  4 {
  5   printf("begin\n");/*I break here*/
  6   printf("%d\n",c); /*I wish to jump 1 line here*/
  7 }
  8 void fb(){}
  9 
 10 int main(){
 11   int b=1;
 12   int i=2;
 13   fa('a');
 14   fb();             /*I also want to jump here*/
 15   return 0;
 16 }

然后使用 gcc test.c -g 编译它，并使用 gdb a.out 运行编译它。

gdb a.out
GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
...
(gdb) b 5
Breakpoint 1 at 0x400571: file test.c, line 5.
(gdb) r
Starting program: /home/Troskyvs/a.out 

Breakpoint 1, fa (c=97) at test.c:5
5     printf("begin\n");
(gdb) j 6
Continuing at 0x40057b.
97                       # This line is odd!
[Inferior 1 (process 6583) exited normally]
(gdb) f
No stack.                # Why it doesn't print line 6 source code
(gdb) j 14
The program is not being run.
                         # What happen here?

I also tried "jump +1" and "jump +14". Same result, don't work.

"jump" 如何按照我的方式工作？

Answer 1

好吧，它正在执行您要求它执行的操作。它

跳到第6行
执行了代码 printf("%d\n",c);，打印了值 (97)。 See here to know why the value is 97
继续执行，执行完毕。证明

[Inferior 1 (process 6583) exited normally]

那么，您的程序已经结束了。不再是运行.

FWIW，如果你想stop/interrupt正常执行再次，你必须设置多个断点after[=31] =] 让它等待的跳转目的地。

GDB "jump" 命令没有跳转到有效上下文？

GDB "jump" command doesn't jump to a valid context?

c

gcc

gdb

skip