The generated store_dart_post_cobject() has the wrong signature / 'stdarg.h' file not found in Linux / stdbool.h / ...

Try to run code generator with working directory at /, or set the environment variable:

export CPATH="$(clang -v 2>&1 | grep "Selected GCC installation" | rev | cut -d' ' -f1 | rev)/include"

as described in ffigen #257, or add include path as is described in #108. This is a problem with Rust's builtin Command. See also: #472 & #494.

Issue with store_dart_post_cobject

If calling rust function gives the error below, please consider running cargo build again. This can happen when the generated rs file is not included when building is being done.

[ERROR:flutter/lib/ui/] Unhandled Exception: Invalid argument(s): Failed to lookup symbol 'store_dart_post_cobject': target/debug/ undefined symbol: store_dart_post_cobject

Error running cargo ndk: ld: error: unable to find library -lgcc

Downgrade Android NDK to version 22. This is an ongoing issue with cargo-ndk, a library unrelated to flutter_rust_bridge but solely used to build the examples, when using Android NDK version 23. (See #149)

Fail to run flutter_rust_bridge_codegen on MacOS, "Please supply one or more path/to/llvm..."

If you are running macOS, you will need to specify a path to your llvm:

flutter_rust_bridge_codegen --rust-input path/to/your/ --dart-output path/to/file/being/bridge_generated.dart --llvm-path /usr/local/homebrew/opt/llvm/

You can install llvm using brew install llvm and it will be installed at /usr/local/homebrew/opt/llvm/ by default.

Freezed file is sometimes not generated when it should be

If your .freezed.dart or .g.dart seems outdated, ensure you have run the build_runner.


Can't create typedef from non-function type.

Ensure min sdk version of Flutter pubspec.yaml is at least 2.17.0 to let ffigen happy.

Imported from both bridge_definitions.dart and

If you use a Rust type with Kind in it's name it may conflict with some generated types which can cause a duplicate import error. The workaround is to avoid using Kind as a suffix for a type name in Rust. See issue #757 for more details.

Error on iOS TestFlight only (store_dart_post_cobject)

You may have an iOS app that works fine in Debug and Release modes locally but when deployed to TestFlight an error occurs trying to locate the store_dart_post_cobject - this is because the nested XCode project for the native bindings maybe be stripping symbols from the linked product.

Select the scheme (eg: Product > Scheme > native-staticlib) and go to Build Settings then under the Deployment section change Strip Linked Product to No; you may also need to change Strip Style to Debugging Symbols.

Generated code is so long

Indeed all generated code are necessary (if you find something that can be simplified, file an issue). Moreover, other code generation tools also generate long code - for example, when using Google protobuf, a very popular serialization library, I see >10k lines of Java code generated for a quite simple source proto file.

Why need Dart 2.17.0

Dart SDK >=2.15.0 is supported by this library, but by the latest version of the ffigen tool requires >=2.17.0. Therefore, write sdk: ">=2.17.0 <3.0.0" in the environment section of pubspec.yaml. If you do not want that, consider installing a older version of the ffigen tool.

Why doesn't flutter_rust_bridge_serve work on Firefox?

This is a known issue stemming from Firefox's stricter rules regarding cross-origin requests. Use Chromium for testing, and check out this guide on enabling crossOriginIsolated for your production servers.

Issues on Web?

Check out Limitations on WASM for some common problems and solutions to adapt existing code to WASM.

Other problems?

Don't hesitate to open an issue! I usually reply within minutes or hours (except when sleeping, of course).