| # Objective C example |
| |
| This example shows how to use ffigen to generate bindings for an Objective C |
| library. It uses the AVFAudio framework to play audio files. |
| |
| ``` |
| dart play_audio.dart test.mp3 |
| ``` |
| |
| ## Config notes |
| |
| The ffigen config for an Objective C library looks very similar to a C library. |
| The most important difference is that you must set `language: objc`. If you want |
| to filter which interfaces are included you can use the `objc-interfaces:` |
| option. This works similarly to the other filtering options. |
| |
| It is recommended that you filter out just about everything you're not |
| interested in binding (see the ffigen config in [pubspec.yaml](./pubspec.yaml)). |
| Virtually all Objective C libraries depend on Apple's internal libraries, which |
| are huge. Filtering can reduce the generated bindings from millions of lines to |
| tens of thousands. You can use the `exclude-all-by-default` flag, or exclude |
| individual sets of declarations like this: |
| |
| ```yaml |
| functions: |
| exclude: |
| - '.*' |
| # Same for structs/unions/enums etc. |
| ``` |
| |
| In this example, we're only interested in `AVAudioPlayer`, so we've filtered out |
| everything else. But ffigen will automatically pull in anything referenced by |
| any of the fields or methods of `AVAudioPlayer`, so we're still able to use |
| `NSURL` etc to load our audio file. |
| |
| ## Generating bindings |
| |
| At the root of this example (`example/objective_c`), run: |
| |
| ``` |
| dart run ffigen --config config.yaml |
| ``` |
| |
| This will generate [avf_audio_bindings.dart](./avf_audio_bindings.dart). |
