Summary - FFI

Combine DynamicLibrary, lookupFunction and Pointer to write a native wrapper.

Summary: FFI

In this group we covered the core pieces of dart:ffi: dart:ffi is the C interop library, DynamicLibrary loads C libraries, lookupFunction binds native functions.

Struct represents C structs, Pointer manages memory addresses. dart:ffi works on native platforms, not on the web. In this summary you will write a native wrapper that combines all of these pieces.

Exercise Summary: A NativeWrapper class

Define a NativeWrapper class with final String library; final String symbol; NativeWrapper(this.library, this.symbol); field and constructor. Add a String describe() => '$library :: $symbol'; method. In main create final w = NativeWrapper('libmylib.so', 'add');; print with print(w.describe());.

Show example solution

class NativeWrapper {
  final String library;
  final String symbol;
  NativeWrapper(this.library, this.symbol);
  String describe() => '$library :: $symbol';
}

void main() {
  final w = NativeWrapper('libmylib.so', 'add');
  print(w.describe());
}

Test yourself

What is DynamicLibrary used for?
- For UI rendering
- For garbage collection
- For loading C libraries
- For package download
Show answer

For loading C libraries — DynamicLibrary loads C libraries.
Match the FFI parts

dart:ffi

C interop
DynamicLibrary

Library loader
lookupFunction

Symbol lookup
Pointer

Memory address

A native function symbol

final symbol = '____';
print(symbol);

Show answer

final symbol = 'add';
print(symbol);

Next lesson: What are extensions?

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