diff --git a/src/content/packages-and-plugins/developing-packages.md b/src/content/packages-and-plugins/developing-packages.md index 94a2c5f8c1..aa264a5137 100644 --- a/src/content/packages-and-plugins/developing-packages.md +++ b/src/content/packages-and-plugins/developing-packages.md @@ -1020,7 +1020,6 @@ PENDING [federated plugins]: #federated-plugins [ffigen docs]: {{site.pub-pkg}}/ffigen/install [Android]: /platform-integration/android/c-interop -[iOS]: /platform-integration/ios/c-interop [macOS]: /platform-integration/macos/c-interop [`fluro`]: {{site.pub}}/packages/fluro [Flutter editor]: /tools/editors diff --git a/src/content/platform-integration/android/c-interop.md b/src/content/platform-integration/android/c-interop.md index ff52225d09..9dc5fe05e2 100644 --- a/src/content/platform-integration/android/c-interop.md +++ b/src/content/platform-integration/android/c-interop.md @@ -26,14 +26,13 @@ _native interface_ and _language bindings._ :::note This page describes using the `dart:ffi` library in Android apps. For information on iOS, see -[Binding to native iOS code using dart:ffi][ios-ffi]. +Binding to native iOS code using `dart:ffi`. For information in macOS, see [Binding to native macOS code using dart:ffi][macos-ffi]. This feature is not yet supported for web plugins. ::: -[ios-ffi]: /platform-integration/ios/c-interop [dart:ffi]: {{site.dart.api}}/dart-ffi/dart-ffi-library.html [macos-ffi]: /platform-integration/macos/c-interop [FFI]: https://en.wikipedia.org/wiki/Foreign_function_interface diff --git a/src/content/platform-integration/index.md b/src/content/platform-integration/index.md index c2a9bfa8f9..9a209d7370 100644 --- a/src/content/platform-integration/index.md +++ b/src/content/platform-integration/index.md @@ -188,14 +188,6 @@ Learn how to add custom integrations with iOS to your Flutter app.

Learn about plugins that support functionality from native iOS frameworks.

- -
- Bind to native code -
-
-

Learn how to bind to native C, Objective-C, and Swift code from your app.

-
-
Embed an iOS view diff --git a/src/content/platform-integration/ios/c-interop.md b/src/content/platform-integration/ios/c-interop.md deleted file mode 100644 index 7a8acca11f..0000000000 --- a/src/content/platform-integration/ios/c-interop.md +++ /dev/null @@ -1,232 +0,0 @@ ---- -title: "Binding to native iOS code using dart:ffi" -description: "To use C code in your Flutter program, use the dart:ffi library." ---- - -:::warning -This page documents a legacy approach to C interop on iOS. - -Since Flutter 3.38, we recommend using a `package_ffi` template with -[build hooks](/platform-integration/bind-native-code) for C interop. - -However, the legacy FFI plugin template (`plugin_ffi`) documented here is -still useful if you need to: -- Access the Flutter Plugin API. -- Use static linking. -::: - - - -Flutter mobile and desktop apps can use the -[dart:ffi][] library to call native C APIs. -_FFI_ stands for [_foreign function interface._][FFI] -Other terms for similar functionality include -_native interface_ and _language bindings._ - -:::note -This page describes using the `dart:ffi` library -in iOS apps. For information on Android, see -[Binding to native Android code using dart:ffi][android-ffi]. -For information in macOS, see -[Binding to native macOS code using dart:ffi][macos-ffi]. -This feature is not yet supported for web plugins. -::: - -[android-ffi]: /platform-integration/android/c-interop -[macos-ffi]: /platform-integration/macos/c-interop -[dart:ffi]: {{site.dart.api}}/dart-ffi/dart-ffi-library.html -[FFI]: https://en.wikipedia.org/wiki/Foreign_function_interface - -Before your library or program can use the FFI library -to bind to native code, you must ensure that the -native code is loaded and its symbols are visible to Dart. -This page focuses on compiling, packaging, -and loading iOS native code within a Flutter plugin or app. - -This tutorial demonstrates how to bundle C/C++ -sources in a Flutter plugin and bind to them using -the Dart FFI library on iOS. -In this walkthrough, you'll create a C function -that implements 32-bit addition and then -exposes it through a Dart plugin named "native_add". - -## Dynamic vs static linking - -A native library can be linked into an app either -dynamically or statically. A statically linked library -is embedded into the app's executable image, -and is loaded when the app starts. - -Symbols from a statically linked library can be -loaded using `DynamicLibrary.executable` or -`DynamicLibrary.process`. - -A dynamically linked library, by contrast, is distributed -in a separate file or folder within the app, -and loaded on-demand. On iOS, the dynamically linked -library is distributed as a `.framework` folder. - -A dynamically linked library can be loaded into -Dart using `DynamicLibrary.open`. - -API documentation is available from the -[Dart API reference documentation][]. - - -[Dart API reference documentation]: {{site.dart.api}} - -## Create an FFI plugin - -To create an FFI plugin called "native_add", -do the following: - -```console -$ flutter create --platforms=android,ios,macos,windows,linux --template=plugin_ffi native_add -$ cd native_add -``` - -:::note -You can exclude platforms from `--platforms` that you don't want -to build to. However, you need to include the platform of -the device you are testing on. -::: - -This will create a plugin with C/C++ sources in `native_add/src`. -These sources are built by the native build files in the various -os build folders. - -The FFI library can only bind against C symbols, -so in C++ these symbols are marked `extern "C"`. - -You should also add attributes to indicate that the -symbols are referenced from Dart, -to prevent the linker from discarding the symbols -during link-time optimization. -`__attribute__((visibility("default"))) __attribute__((used))`. - -On iOS, the `native_add/ios/native_add.podspec` links the code. - -The native code is invoked from dart in `lib/native_add_bindings_generated.dart`. - -The bindings are generated with [package:ffigen]({{site.pub-pkg}}/ffigen). - -## Other use cases - -### iOS and macOS - -Dynamically linked libraries are automatically loaded by -the dynamic linker when the app starts. Their constituent -symbols can be resolved using [`DynamicLibrary.process`][]. -You can also get a handle to the library with -[`DynamicLibrary.open`][] to restrict the scope of -symbol resolution, but it's unclear how Apple's -review process handles this. - -Symbols statically linked into the application binary -can be resolved using [`DynamicLibrary.executable`][] or -[`DynamicLibrary.process`][]. - - -[`DynamicLibrary.executable`]: {{site.dart.api}}/dart-ffi/DynamicLibrary/DynamicLibrary.executable.html -[`DynamicLibrary.open`]: {{site.dart.api}}/dart-ffi/DynamicLibrary/DynamicLibrary.open.html -[`DynamicLibrary.process`]: {{site.dart.api}}/dart-ffi/DynamicLibrary/DynamicLibrary.process.html - -#### Platform library - -To link against a platform library, -use the following instructions: - -1. In Xcode, open `Runner.xcworkspace`. -1. Select the target platform. -1. Click **+** in the **Linked Frameworks and Libraries** - section. -1. Select the system library to link against. - -#### First-party library - -A first-party native library can be included either -as source or as a (signed) `.framework` file. -It's probably possible to include statically linked -archives as well, but it requires testing. - -#### Source code - -To link directly to source code, -use the following instructions: - - 1. In Xcode, open `Runner.xcworkspace`. - 2. Add the C/C++/Objective-C/Swift - source files to the Xcode project. - 3. Add the following prefix to the - exported symbol declarations to ensure they - are visible to Dart: - - **C/C++/Objective-C** - - ```objc - extern "C" /* <= C++ only */ __attribute__((visibility("default"))) __attribute__((used)) - ``` - - **Swift** - - ```swift - @_cdecl("myFunctionName") - ``` - -#### Compiled (dynamic) library - -To link to a compiled dynamic library, -use the following instructions: - -1. If a properly signed `Framework` file is present, - open `Runner.xcworkspace`. -1. Add the framework file to the **Embedded Binaries** - section. -1. Also add it to the **Linked Frameworks & Libraries** - section of the target in Xcode. - -#### Open-source third-party library - -To create a Flutter plugin that includes both -C/C++/Objective-C _and_ Dart code, -use the following instructions: - -1. In your plugin project, - open `ios/.podspec`. -1. Add the native code to the `source_files` - field. - -The native code is then statically linked into -the application binary of any app that uses -this plugin. - -#### Closed-source third-party library - -To create a Flutter plugin that includes Dart -source code, but distribute the C/C++ library -in binary form, use the following instructions: - -1. In your plugin project, - open `ios/.podspec`. -1. Add a `vendored_frameworks` field. - See the [CocoaPods example][]. - -:::warning -**Do not** upload this plugin -(or any plugin containing binary code) to pub.dev. -Instead, this plugin should be downloaded -from a trusted third-party, -as shown in the CocoaPods example. -::: - -[CocoaPods example]: {{site.github}}/CocoaPods/CocoaPods/blob/master/examples/Vendored%20Framework%20Example/Example%20Pods/VendoredFrameworkExample.podspec - -## Stripping iOS symbols - -When creating a release archive (IPA), -the symbols are stripped by Xcode. - -1. In Xcode, go to **Target Runner > Build Settings > Strip Style**. -2. Change from **All Symbols** to **Non-Global Symbols**. - -{% render "docs/resource-links/ffi-video-resources.md", site: site %} diff --git a/src/content/platform-integration/ios/setup.md b/src/content/platform-integration/ios/setup.md index 327f97b487..787e8665aa 100644 --- a/src/content/platform-integration/ios/setup.md +++ b/src/content/platform-integration/ios/setup.md @@ -262,9 +262,6 @@ or begin improving integration with iOS.
  • Build and deploy to iOS
    • -
  • - Bind to native iOS code -
  • Leverage system frameworks
    • diff --git a/src/content/platform-integration/macos/c-interop.md b/src/content/platform-integration/macos/c-interop.md index a0e8d65d68..05b8d3abab 100644 --- a/src/content/platform-integration/macos/c-interop.md +++ b/src/content/platform-integration/macos/c-interop.md @@ -35,7 +35,6 @@ This feature is not yet supported for web plugins. [android-ffi]: /platform-integration/android/c-interop -[ios-ffi]: /platform-integration/ios/c-interop [dart:ffi]: {{site.dart.api}}/dart-ffi/dart-ffi-library.html [FFI]: https://en.wikipedia.org/wiki/Foreign_function_interface