# Pass variable via blueprintimplementableevent not working

**URL:** <https://forums.unrealengine.com/t/pass-variable-via-blueprintimplementableevent-not-working/295471>\
**Category:** Blueprint\
**Tags:** unreal-engine, CPP, Blueprint, question\
**Created:** [October 7, 2014, 6:57am UTC](https://forums.unrealengine.com/t/pass-variable-via-blueprintimplementableevent-not-working/295471 "2014-10-07T06:57:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![robbiecooper](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@robbiecooper](https://forums.unrealengine.com/u/robbiecooper)\
**Post date:** [October 7, 2014, 6:57am UTC](https://forums.unrealengine.com/t/pass-variable-via-blueprintimplementableevent-not-working/295471/1 "2014-10-07T06:57:28Z")

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Hi All

I’m following this;

> **[C++ and Blueprint Interaction Problems, Pointers?](https://forums.unrealengine.com/showthread.php?2364-C-and-Blueprint-Interaction-Problems-Pointers)**
>
> Hey guys. I fought and fought but now I think I’m stuck. Hope you can give me a hint. The basic structure that I’m working on: A - There’s a C++ ‘MyController’ class. It also includes an Array of custom MyStructs. B - Then there’s a C++...

Jeff Farris’s answer, in order to send a FHitEvent to blueprints from C++. I’m passing by reference to avoid exposing a pointer.

```
UFUNCTION(BlueprintImplementableEvent, Category = "MyStuff")
void OnCameraTrace(struct FHitResult& RV_Hit);

```

However, it compiles, but is not accessible in blueprints. It simply doesnt appear in the editor. Has something changed in the engine since that answer was posted?

Thanks!!!

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<div class="post-metadata">

**Author:** ![robbiecooper](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@robbiecooper](https://forums.unrealengine.com/u/robbiecooper)\
**Post date:** [October 7, 2014, 7:22am UTC](https://forums.unrealengine.com/t/pass-variable-via-blueprintimplementableevent-not-working/295471/2 "2014-10-07T07:22:59Z")

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If you’re having this problem, I recommend Rama’s tutorial;

> **[A new, community-hosted Unreal Engine Wiki](https://forums.unrealengine.com/t/a-new-community-hosted-unreal-engine-wiki/141494)**
>
> After over a year in maintenance mode, the official Unreal Engine Wiki is now permanently offline. These resources now live on a new community-run Unreal Engine Community Wiki — ue4community.wiki! You will be able to find content from the official...

Passing by const solved it.