What is FFI?

Call C libraries with dart:ffi.

What is FFI?

dart:ffi lets you call C libraries from Dart code. It binds functions written in C to Dart, providing interop; calls happen directly without bridge code.

import 'dart:ffi';

// In C: int topla(int a, int b);
typedef NativeTopla = Int32 Function(Int32 a, Int32 b);
typedef DartTopla = int Function(int a, int b);

NativeFunction and typedef

You define the C function signature on the Dart side with two typedefs: one for the NativeFunction on the C side (Int32, Pointer), and one for the Dart side (int). The two types are bridged by lookupFunction.

Exercise Define FFI typedefs

Define the typedefs NativeTopla = Int32 Function(Int32 a, Int32 b) and DartTopla = int Function(int a, int b). In main, print 'ffi hazir'.

Show example solution

import 'dart:ffi';

typedef NativeTopla = Int32 Function(Int32 a, Int32 b);
typedef DartTopla = int Function(int a, int b);

void main() {
  print('ffi hazir');
}

Test yourself

What does dart:ffi provide?
- Opening a database
- Calling C libraries from Dart
- Making HTTP requests
- Drawing widgets
Show answer

Calling C libraries from Dart — dart:ffi binds C functions to Dart so they can be called directly; HTTP, widgets, or databases are not ffi's job.
Import dart:ffi
```
import 'dart:____';
```
Show answer
```
import 'dart:ffi';
```
FFI matches

dart:ffi

C interop library
C

System programming language
interop

Cross-language bridge
NativeFunction

C-side signature

Next lesson: DynamicLibrary

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