gdb中的下一个命令无法正常工作 [英] next command in gdb is not working correctly

问题描述

我只是简单地使用gdb逐行浏览代码，以了解它是如何工作的以及它在做什么。第一次做到这一点时它运行良好，但现在下一个命令不能正常工作。有时它往前走，有时往后退。这没有意义。每次我这样做的时候，似乎都是一样的模式。下面是一个例子。任何人都知道什么是错的？

注意：这是一个旧的Mac，旧的程序版本（我没有更新的权力）

请明确。

谢谢！

 阅读共享库的符号...完成
（gdb）b main 
 0x2730的断点1：文件../../../../gcc-3.4.6/libf2c/ libF77 / pow_zi.c，第14行
（gdb）r 
启动程序：/ Users / kevinsanchez / epeace / ConstU / main 
 n读取共享库+的符号。完成
重新设置断点1时出错：
未定义函数main。 
重新启用共享库断点：1 
 
 main.c中main（）中的断点1，0x00002730：34 
 34 {
（gdb）n 
 $ main（）at main.c：42 
 42 for（i = 0; i （gdb）n 
 34 {
（gdb） n 
 35 runstart = clock（）; 
（gdb）n 
 39 Init = ReadInit（&CaseDim）; / *从初始化文件读入初始值* / 
（gdb）n 
 35 runstart = clock（） ; 
（gdb）n 
 39 Init = ReadInit（&CaseDim）; / *从初始化文件读入初始值* / 
（gdb）
  
 
解决方案
 
 
 
任何人都知道什么是错的？
 
 
在调试使用优化构建的程序时，您描述的症状非常普遍：编译器重新排列代码的方式使得不同的行会混合在一起。
 
 
 
确保您编译时没有任何 -O 标志，或者添加 -O0 。
 
 
这里是make文件的一部分： CC = gcc   CFLAGS = -g -O2  
 
 
这样做：删除 -O2 并且您的调试将变得更容易。
 
I am simply using gdb to step through a code line by line to learn how it is working and what it is doing. It worked fine the first time I did this, but now the next command is not working right. Sometimes it goes forward, sometimes it goes backwards. It doesn't make sense. Every time I do this it seems to be the same pattern. Below is an example. Anyone know what is wrong?

Note: This is an old Mac with old program versions (That I do not have the power to update)

Please be explicit. I am fairly new to linux and programming in general.

Thanks!
Reading symbols for shared libraries ... done
(gdb) b main
Breakpoint 1 at 0x2730: file ../../../../gcc-3.4.6/libf2c/libF77/pow_zi.c, line 14.
(gdb) r
Starting program: /Users/kevinsanchez/epeace/ConstU/main 
nReading symbols for shared libraries +. done
Error in re-setting breakpoint 1:
Function "main" not defined.
Re-enabling shared library breakpoints: 1

Breakpoint 1, 0x00002730 in main () at main.c:34
34      {
(gdb) n
main () at main.c:42
42      for (i=0;i<DpDIM;i++) {
(gdb) n
34      {
(gdb) n
35      runstart=clock();
(gdb) n
39      Init=ReadInit(&CaseDim);/*reads in initial valies from initfile*/
(gdb) n
35      runstart=clock();
(gdb) n
39      Init=ReadInit(&CaseDim);/*reads in initial valies from initfile*/
(gdb) 

解决方案

  
Anyone know what is wrong?
The symptoms you've described are very common when debugging programs built with optimization: the compiler re-arranges code in such a way that instructions from different lines become intermixed.

Make sure you compile without any -O flags, or add -O0 at the end of your compilation lines.

  
here is part of the make file: CC = gcc CFLAGS = -g -O2
That would do it: remove -O2 and your debugging would go much easier.

                        
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