International Components for Unicode (ICU) use in Fuchsia

Fuchsia uses the ICU library for the commonly shared internationalization services such as date, time, timezone, locale and language handling.

The ICU library consists roughly of two different parts: the ICU library code which contains the ICU algorithms, and the ICU library data, which contains locale-specific information that is packaged for independent reuse.

Note: For a complete example of using the ICU library in Fuchsia, see //examples/intl/wisdom.

Add ICU library dependencies

Include the necessary library dependencies in your BUILD.gn file:

• {C++}

  The ICU library is a single third-party dependency, used as ${icu_root}:icu

  {% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="examples/intl/wisdom/cpp/client/BUILD.gn" region_tag="icu_library" adjust_indentation="auto" %}
  

• {Rust}

  The rust_icu library is subdivided into several crates that correspond to specific ICU4C headers:

  {% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="examples/intl/wisdom/rust/client/BUILD.gn" region_tag="icu_library" adjust_indentation="auto" %}
  

Import ICU headers

Add the imports for the specific ICU library features your program requires:

• {C++}

  The ICU documentation{: .external} provides additional information about the APIs the library supports.

  {% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="examples/intl/wisdom/cpp/client/intl_wisdom_client.cc" region_tag="imports" adjust_indentation="auto" %}
  

• {Rust}

  The rust_icu reference{: .external} provides additional information about the APIs the library supports.

  {% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="examples/intl/wisdom/rust/client/src/wisdom_client_impl.rs" region_tag="imports" adjust_indentation="auto" %}
  

Initialize ICU data

In Fuchsia, the ICU data must be loaded by the program at runtime. Initialize the ICU data with the icu_data library:

• {C++}

  {% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="examples/intl/wisdom/cpp/server/intl_wisdom_server_impl.cc" region_tag="loader_example" adjust_indentation="auto" %}
  

• {Rust}

  {% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="examples/intl/wisdom/rust/server/src/main.rs" region_tag="loader_example" adjust_indentation="auto" %}
  

For more details instructions on loading ICU data from various sources, see ICU timezone data.

You are now ready to use the ICU library features in your Fuchsia program.