doc/docs/en/manuals/extensions-build-variants.md

---

title: Native extensions - Build variants

brief: This manual describes the different builds variants that Defold can create and how they interact with native extensions and the engine.

:Build Variants

App Manifest

Not only can you add native code to the engine with the Native Extensions feature, you can also remove standard parts of the engine. E.g. if you don't need a physics engine, you can remove that from the executable. Learn how to exclude unused feature in the application manifest manual.

Combined context

The app manifest actually has the same structure and syntax as the extension manifest. This allows us to merge the contexts for one platform together when finally building.

And, Defold itself, has its own build manifest as the foundation (build.yml). For each extension that is built, the manifests are combined as follows:

manifest = merge(game.appmanifest, ext.manifest, build.yml)

This is so the user can override the default behaviour of the engine and also each extension. And, for the final link stage, we merge the app manifest with the defold manifest:

manifest = merge(game.appmanifest, build.yml)

Syntax

Here is an example for reference:

platforms:
    x86_64-osx:
        context:
            excludeLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    x86_64-linux:
        context:
            excludeLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    js-web:
        context:
            excludeLibs: []
            excludeJsLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    wasm-web:
        context:
            excludeLibs: []
            excludeJsLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    x86-win32:
        context:
            excludeLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    x86_64-win32:
        context:
            excludeLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    armv7-android:
        context:
            excludeLibs: []
            excludeJars: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    armv7-ios:
        context:
            excludeLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []
    arm64-ios:
        context:
            excludeLibs: []
            excludeSymbols: []
            libs: []
            linkFlags: []

White listing

For all the keywords, we apply white listing filter. This is to avoid illegal path handling and accessing files outside of the build upload folder.

linkFlags

Here you can add flags to the specific platform compiler.

libs

This flag is only used if you wish to add a library that is part of the platform or Defold SDK. All libraries in your app's extensions are added automatically, and you shouldn't add those to this flag. Here's an example where the 3D physics is removed from the engine:

x86_64-linux:
    context:
        excludeLibs: ["physics","LinearMath","BulletDynamics","BulletCollision"]
        excludeSymbols: []
        libs: ["physics_2d"]
        linkFlags: []

Exclude flags

These flags are used to remove things previously defined in the platform context. Here's an example of how to remove the Facebook extension from the engine (Note the (.*) which is a regexp to help remove the correct items).

armv7-android:
    context:
        excludeLibs: ["facebookext"]
        excludeJars: ["(.*)/facebooksdk.jar","(.*)/facebook_android.jar"]
        excludeSymbols: ["FacebookExt"]
        libs: []
        linkFlags: []

Where's the list of all flags, libraries, symbols???

We might put some of them here, but we also think our time is better spent completing the feature of moving the manifest configuration into the Editor, making it a seamless step for the user.

In the meantime, we'll keep the Manifestation tool updated.