moonbit-c-binding

MoonBit C bindings are created by declaring `extern "c"` functions, implementing C stubs with `moonbit.h`, and configuring `moon.pkg` for native builds. This FFI layer workflow maps C types to MoonBit types and handles the native interoperability safely.

Memory management in MoonBit C FFI uses ownership annotations like `#borrow` and `#owned` to handle external objects safely. These annotations define whether MoonBit or the C library manages the lifecycle of allocated resources across the FFI boundary.

Configuring `moon.pkg` for native C stubs involves specifying the `native-stub` field to point to your `.c` files and using `link.native` to link the required C libraries. This setup ensures the MoonBit compiler includes your C code during the native build process.

Yes, you can use callbacks from C libraries in MoonBit by implementing callback trampolines. These trampolines bridge C function pointers back into MoonBit, allowing native C libraries to execute MoonBit functions asynchronously or during synchronous calls.

The best way to validate MoonBit C FFI bindings is by using AddressSanitizer. It detects memory leaks, buffer overflows, and use-after-free errors across the FFI boundary, ensuring your ownership annotations and pointer wrapping are correctly implemented.

Common pitfalls when mapping C types to MoonBit include mishandling string conversions, failing to wrap raw C pointers securely, and incorrectly assigning ownership annotations. The FFI workflow addresses these by using external object patterns and dedicated conversion routines.