# Custom Engine - Macro

**URL:** <https://forums.unrealengine.com/t/custom-engine-macro/373200>\
**Category:** Platform & Builds\
**Tags:** macros, build, unreal-engine, UE4, CPP, question\
**Created:** [October 13, 2016, 8:21am UTC](https://forums.unrealengine.com/t/custom-engine-macro/373200 "2016-10-13T08:21:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lukaszj2015](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@lukaszj2015](https://forums.unrealengine.com/u/lukaszj2015)\
**Post date:** [October 13, 2016, 8:21am UTC](https://forums.unrealengine.com/t/custom-engine-macro/373200/1 "2016-10-13T08:21:35Z")

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Hello,  
I’m finding for UE macro to seperate code for custom build engine. Is in UE something like this?

```
#if USING_CUSTOM_ENGINE
   //..code
#endif
```

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<div class="post-metadata">

**Author:** ![Moss](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/moss/32/704032_2.png) [@Moss](https://forums.unrealengine.com/u/Moss)\
**Post date:** [October 13, 2016, 9:31am UTC](https://forums.unrealengine.com/t/custom-engine-macro/373200/2 "2016-10-13T09:31:11Z")

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A simple way to define your custom engine would be adding your define to `Engine/Source/Runtime/Core/Public/Misc/Build.h`. You could also modify `UBT` to export your define when building the engine. In both cases ensure to add some `start` and `end` comments to flag your changes that are not wrapped within your custom define.