olm-sys: Low Level Bindings For Olm

This is an intermediate crate that exposes the C API of libolm to Rust. If you want to start building things with libolm from Rust, check out olm-rs.

Supported Platforms

• Android
• Linux
• macOS
• Windows
• FreeBSD
• WebAssembly

Building

This library can either be built by statically or dynamically linking against libolm:

Static

This is the default and requires no further action. libolm is built locally and then linked against statically.

Build dependencies

• libstdc++/libc++
• cmake (requires v3.12)
• GNU make or a compatible variant (WebAssembly only)
• Emscripten (WebAssembly only)

Dynamic

For linking against libolm dynamically, first make sure that you have the library in your link path. Then build this library with the OLM_LINK_VARIANT environment variable set to dylib.

For example, building your project using olm-sys as a dependency would look like this:

$ OLM_LINK_VARIANT=dylib cargo build

Cross compiling for Android

To enable cross compilation for Android set the environment variable ANDROID_NDK to the location of your NDK installation, for example:

$ ANRDOID_NDK=/home/user/Android/Sdk/ndk/22.0.7026061/

The linker needs to be set to an target specific one as well, for example for aarch64-linux-android set this into your cargo config:

[target.aarch64-linux-android]
ar = "/home/user/Android/Sdk/ndk/22.0.7026061/toolchains/llvm/prebuilt/linux-x86_64/bin/ar"
linker = "/home/user/Android/Sdk/ndk/22.0.7026061/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android30-clang"

After both of these are set, compilation should work as usual using cargo:

$ ANDROID_NDK=~/Android/Sdk/ndk/22.0.7026061 cargo build --target aarch64-linux-android

Cross compiling for iOS

To enable cross compilation for iOS, set the environment variable IOS_SDK_PATH to the iOS SDK location by running:

$ export IOS_SDK_PATH=`xcrun --show-sdk-path --sdk iphoneos`