This folder contains various FFI crates for ICU4X.

The primary ICU4X FFI API is generated via diplomat and can be found under ffi/diplomat (crate name icu_capi), alongside generated C, C++, and WASM bindings.

Due to cargo #4881, it's not possible for crate-types to be selectively built, and this can cause problems when designing FFI crates to be built on different platforms. For that reason, the ffi/diplomat icu_capi crate only builds as an rlib and should not be used directly when performing FFI. Instead, the icu_capi_staticlib (ffi/capi_staticlib) or icu_capi_cdylib (ffi/capi_cdylib) crates should be built to get the appropriate staticlib or cdylib target.

Some platforms and build systems will have special bindings: currently we have one such case: FreeRTOS. If you wish to build ICU4X for FreeRTOS, use the ffi/freertos (icu_freertos) crate.

The ffi/ecma402 (icu4x_ecma402) crate contains an implementation of the ecma402_traits traits, enabling compatibility testing against ICU.