如何使用 gdb 进行调试? [英] How to debug using gdb?

问题描述

我正在尝试在我的程序中添加断点

I am trying to add a breakpoint in my program using

b {line number}

但我总是收到一条错误消息:

but I am always getting an error that says:

No symbol table is loaded.  Use the "file" command.

我该怎么办?

推荐答案

这里有一个gdb的快速入门教程:

Here is a quick start tutorial for gdb:

/* test.c  */
/* Sample program to debug.  */
#include <stdio.h>
#include <stdlib.h>

int
main (int argc, char **argv) 
{
  if (argc != 3)
    return 1;
  int a = atoi (argv[1]);
  int b = atoi (argv[2]);
  int c = a + b;
  printf ("%d
", c);
  return 0;
}

使用 -g3 选项进行编译.g3 包括额外的信息，例如程序中存在的所有宏定义.

Compile with the -g3 option. g3 includes extra information, such as all the macro definitions present in the program.

gcc -g3 -o test test.c

将现在包含调试符号的可执行文件加载到 gdb 中:

Load the executable, which now contain the debugging symbols, into gdb:

gdb --annotate=3 test.exe 

现在您应该会在 gdb 提示符下找到自己.在那里你可以向 gdb 发出命令.假设您想在第 11 行放置一个断点并逐步执行，打印局部变量的值 - 以下命令序列将帮助您执行此操作:

Now you should find yourself at the gdb prompt. There you can issue commands to gdb. Say you like to place a breakpoint at line 11 and step through the execution, printing the values of the local variables - the following commands sequences will help you do this:

(gdb) break test.c:11
Breakpoint 1 at 0x401329: file test.c, line 11.
(gdb) set args 10 20
(gdb) run
Starting program: c:Documents and SettingsVMathewDesktop/test.exe 10 20
[New thread 3824.0x8e8]

Breakpoint 1, main (argc=3, argv=0x3d5a90) at test.c:11
(gdb) n
(gdb) print a
$1 = 10
(gdb) n
(gdb) print b
$2 = 20
(gdb) n
(gdb) print c
$3 = 30
(gdb) c
Continuing.
30

Program exited normally.
(gdb) 

简而言之，以下命令就是您开始使用 gdb 所需的全部内容:

In short, the following commands are all you need to get started using gdb:

break file:lineno - sets a breakpoint in the file at lineno.
set args - sets the command line arguments.
run - executes the debugged program with the given command line arguments.
next (n) and step (s) - step program and step program until it 
                        reaches a different source line, respectively. 
print - prints a local variable
bt -  print backtrace of all stack frames
c - continue execution.

在 (gdb) 提示符下键入帮助以获取所有有效命令的列表和说明.

Type help at the (gdb) prompt to get a list and description of all valid commands.

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