# How does Unreal packs its first-party dlls with the game .exe?

**URL:** <https://forums.unrealengine.com/t/how-does-unreal-packs-its-first-party-dlls-with-the-game-exe/451369>\
**Category:** Platform & Builds\
**Tags:** dll, deployment, build, unreal-engine, question\
**Created:** [June 27, 2019, 2:41pm UTC](https://forums.unrealengine.com/t/how-does-unreal-packs-its-first-party-dlls-with-the-game-exe/451369 "2019-06-27T14:41:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Hitsaru](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Hitsaru](https://forums.unrealengine.com/u/Hitsaru)\
**Post date:** [June 27, 2019, 2:41pm UTC](https://forums.unrealengine.com/t/how-does-unreal-packs-its-first-party-dlls-with-the-game-exe/451369/1 "2019-06-27T14:41:32Z")

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When you build Unreal’s source code it generates lots off dlls, when you use the built engine to deploy a game the result is a game with a single executable. How does Unreal packs its first-party dlls into a single .exe?

There is a preprocessor called IS\_MONOLITHIC in the engines code but changing its value for deploying wouldn’t require the full engine to be rebuilt?

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**Author:** ![Hitsaru](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Hitsaru](https://forums.unrealengine.com/u/Hitsaru)\
**Post date:** [November 26, 2019, 1:51am UTC](https://forums.unrealengine.com/t/how-does-unreal-packs-its-first-party-dlls-with-the-game-exe/451369/2 "2019-11-26T01:51:05Z")

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I’ve just figured out.

In the IMPLEMENT\_MODULE macro there is an IMPLEMENT\_MODULE\_##ClassName that the builder adds to the linker’s property /INCLUDE. This forces the linker to reference the module.