Overview

The C-Interop feature of the Kreate Gradle plugin provides a fully automated pipeline for bridging Kotlin/Native multiplatform projects with native Rust libraries. When enabled, Kreate orchestrates every step — from initializing a Rust project via Cargo, adding dependencies, compiling for multiple native targets, generating C headers with cbindgen, producing Kotlin/Native .def files, and wiring the resulting static libraries into your Kotlin Multiplatform build — all without manual setup.

Pipeline Overview

The C-Interop pipeline consists of six ordered Gradle tasks that run automatically before any Kotlin/Native compilation:

Step	Task	Description
1	`kreate-c-interop-initialize`	Creates a new Rust library project with `cargo new --lib`
2	`kreate-c-interop-dependencies`	Adds `libc` and `cbindgen` (or custom crates) via `cargo add`
3	`kreate-c-interop-configure`	Appends `[lib] crate-type = ["staticlib"]` to `Cargo.toml`
4	`kreate-c-interop-script`	Generates a `build.rs` that runs `cbindgen` to produce C headers
5	`kreate-c-interop-compile`	Runs `cargo build --release --target <target>` for each target
6	`kreate-c-interop-definitions`	Writes the Kotlin/Native `.def` file pointing to the compiled artifacts

After step 6 completes, all CInteropProcess tasks automatically depend on kreate-c-interop-definitions, so your normal build or assemble invocation drives the entire chain.

Native Language Selection

Since Kreate 1.3.0, C-Interop supports C and C++ as first-class native languages alongside Rust. The language option selects the underlying pipeline:

`language`	Toolchain	Pipeline summary
`NativeLanguage.RUST`	Cargo + cbindgen	(default) Initializes a Cargo project and generates headers with `cbindgen`
`NativeLanguage.C`	CMake	Scaffolds a CMake C project and builds a static library bridged via a C header
`NativeLanguage.CPP`	CMake	Scaffolds a CMake C++ project and builds a static library bridged via a C header

For C and CPP, the pipeline is reduced to three tasks:

Step	Task	Description
1	`kreate-c-interop-initialize`	Scaffolds a CMake project with `CMakeLists.txt`, `include/` and `src/`
2	`kreate-c-interop-compile`	Runs `cmake` to build the static library `lib<name>.a`
3	`kreate-c-interop-definitions`	Writes the Kotlin/Native `.def` file pointing to the compiled artifacts

The C/C++ flow requires CMake 3.20 or later and a C/C++ compiler instead of the Rust toolchain. The public API is declared in a hand-written header include/<projectName>.h (using an extern "C" boundary for C++), which Kotlin/Native consumes directly.

Enabling C-Interop

C-Interop is disabled by default. Enable it inside your module's build.gradle.kts within the kreate extension block:

kreate {
    platform {
        multiplatform {
            cInterop {
                enabled.set(true)
            }
        }
    }
}

Once enabled, all six pipeline tasks are registered automatically and execute in order before the first CInteropProcess task runs.

Next Steps

Configuration Reference: DSL reference and all available options
Gradle Tasks: Details on the individual pipeline tasks
Examples: Practical examples and usage patterns
Troubleshooting: Common issues and solutions

Generated Project Layout

After the pipeline runs, the following structure is created inside your Gradle module:

<module>/
└── cinterop/                          ← projectDirectory (default)
    └── <projectName>/                 ← Rust project root
        ├── Cargo.toml                 ← patched with [lib] crate-type = ["staticlib"]
        ├── build.rs                   ← generated cbindgen build script
        ├── src/
        │   └── lib.rs                 ← your Rust library source
        ├── include/
        │   └── <projectName>.h        ← C header generated by cbindgen
        ├── defs/
        │   └── cinterop.def           ← Kotlin/Native definition file
        └── target/
            └── <rustTarget>/
                └── release/
                    └── lib<name>.a    ← compiled static library

C-Interop Package Name

By default, the Kotlin package under which the native symbols are exposed is derived from the Gradle project group and the (lowercased) project name:

<project.group>.<projectName.lowercase()>.cinterop

Override it with packageNameOverride:

cInterop {
    enabled.set(true)
    packageNameOverride.set("com.example.mylib.native")
}

Cargo Command Resolution

On macOS, Kreate looks for cargo at ~/.cargo/bin/cargo (the default rustup install path). On all other platforms, it simply invokes cargo from the system PATH.

24 June 2026