如何在本地作用域变量上设置持久性和条件观察点？ [英] How do I set persistent and conditional watchpoints on locally scoped variables?

问题描述

1. 如果我为当前范围的本地变量设置了一个观察点，那么它将在退出范围时自动删除。有什么方法可以设置一次，并保持它自动活跃，每当进入相同的范围？
   

2. 是否有设置条件观察点，如观察var1 if var1 == 0 ？在我的情况下，条件不起作用。每当 var1 的值发生变化时，gdb停止运行，而不是直到 var1 == 0 为真。我的gdb是GNU gdb 6.8-debian。

我同意戴夫然而，按照你的要求，你可以使用GDB的命令命令来设置GDB命令的列表，以便在命中断点时执行。我认为这非常有用。




我建议您将GDB命令写入文件，以便它们易于编辑，并且易于使用源文件重新加载命令。或者你可以指定要加载到GDB命令行的命令文件或使用.gdbinit自动加载。





一个很好的使用命令：

假设我有一个被许多其他函数调用的函数 format 。我想打破它，但只有在函数 do_step_3 被调用后。

  break do_step_3 
命令
中断格式
继续
结束
  

你可以用这个来解决你的问题，例如：



  break func 
命令
 watch var 
 continue 
 end 
  




1. If I set a watchpoint for a variable local to the current scope, it will be auto deleted when going out of the scope. Is there any way to set it once and keep it auto alive whenever entering the same scope?

2. Is there anyway to set conditional watchpoint, like watch var1 if var1==0? In my case, the condition does't work. gdb stops whenever var1's value is changed, instead of untill var1 == 0 is true. My gdb is GNU gdb 6.8-debian.

解决方案

I agree with Dave that a conditional breakpoint is the way to go.

However, to do what you asked, you can use GDB's commands command to set a list of GDB commands to execute whenever a breakpoint is hit. I find this incredibly useful.

I suggest writing your GDB commands into a file so that they are easy to edit and easy to reload with the source command. Or you can specify command files to load on the GDB command line or use .gdbinit to make them load automatically.

An example of a good use of commands:
Suppose that I have a function format that is called by a lot of other functions. I want to break on it, but only after function do_step_3 has been called.

break do_step_3
commands
  break format
  continue
end

You could use this for your problem with something like:

break func
commands
  watch var
  continue
end

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