lookupFunction

Bind a C function to Dart with lookupFunction.

lookupFunction

lookupFunction makes a C function in a DynamicLibrary callable from Dart. It takes two type parameters: a NativeFunction (C side) and a Dart function type. The returned value is a Dart function.

final topla = lib.lookupFunction<NativeTopla, DartTopla>('topla');

NativeFunction and pointer

NativeFunction carries the C function signature (with types like Int32, Pointer). lookupFunction converts this signature to the Dart side, so pointers and memory addresses are shared safely.

Exercise Look up the getpid symbol

First define the typedefs NativeGetpid = Int32 Function() and DartGetpid = int Function(). In main, get a library with DynamicLibrary.process(), look up the 'getpid' symbol with lookupFunction, and print 'lookup hazir'.

Show example solution

import 'dart:ffi';

typedef NativeGetpid = Int32 Function();
typedef DartGetpid = int Function();

void main() {
  final lib = DynamicLibrary.process();
  final getpid = lib.lookupFunction<NativeGetpid, DartGetpid>('getpid');
  print('lookup hazir');
}

Test yourself

What does lookupFunction return?
- A widget
- A Dart function
- A string
- A C pointer
Show answer

A Dart function — lookupFunction converts a C symbol into a Dart function; the returned value can be called directly like a Dart function.

lookupFunction call

final topla = lib.____<NativeTopla, DartTopla>('topla');

Show answer

final topla = lib.lookupFunction<NativeTopla, DartTopla>('topla');

lookupFunction matches

lookupFunction

Binds a C function
NativeFunction

C function type
pointer

Memory address
symbol

C function name

Next lesson: Pointer

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