# Chapter 24 problem

**URL:** <https://forums.kodeco.com/t/chapter-24-problem/32013>\
**Category:** Advanced Apple Debugging\
**Created:** [July 10, 2017, 8:27pm UTC](https://forums.kodeco.com/t/chapter-24-problem/32013 "2017-07-10T20:27:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![yasroslav](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/yasroslav/32/81494_2.png) [@yasroslav](https://forums.kodeco.com/u/yasroslav)\
**Post date:** [July 10, 2017, 8:27pm UTC](https://forums.kodeco.com/t/chapter-24-problem/32013/1 "2017-07-10T20:27:23Z")

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@lolgrep In chapter 24 on the page 347 there’s such commands:

```
(lldb) po trace_address(0x00007fa838414330)

```

And such command give the following output:

```
error: use of undeclared identifier 'trace_address'

```

It seems that this module isn’t imported in the runtime or in the app at all.  
At least i didn’t find any functions nor module call in the whole application.  
So what should i do?

---

<div class="post-metadata">

**Author:** ![yasroslav](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/yasroslav/32/81494_2.png) [@yasroslav](https://forums.kodeco.com/u/yasroslav)\
**Post date:** [July 10, 2017, 8:55pm UTC](https://forums.kodeco.com/t/chapter-24-problem/32013/2 "2017-07-10T20:55:04Z")

</div>

Don’t know why, but redownloading project fixes this problem.

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<div class="post-metadata">

**Author:** ![lolgrep](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/lolgrep/32/106950_2.png) [@lolgrep](https://forums.kodeco.com/u/lolgrep)\
**Post date:** [July 26, 2017, 10:26pm UTC](https://forums.kodeco.com/t/chapter-24-problem/32013/3 "2017-07-26T22:26:13Z")

</div>

> [@yasroslav](#):
>
> trace\_address

@yasroslav hard to diagnose without further info, but I’d do a `image lookup -rn` to make sure the code is in the process. If you have problems again you can externally declare the function right before calling it