UnionAddress<T extends Union>

extension UnionAddress<T extends Union> on T

Annotations: @Since.new('3.5')

Properties

address extension no setter

Pointer<T> get address

The memory address of the underlying data.

An expression of the form expression.address denoting this address can only occurr as an entire argument expression in the invocation of a leaf Native external function.

Example:

@Native<Void Function(Pointer<MyUnion>)>(isLeaf: true)
external void myFunction(Pointer<MyUnion> pointer);

final class MyUnion extends Union {
  @Int8()
  external int x;
}

void main() {
  final myUnion = Union.create<MyUnion>();
  myFunction(myUnion.address);
}

The expression before .address is evaluated like the left-hand-side of an assignment, to something that gives access to the storage behind the expression, which can be used both for reading and writing. The .address then gives a native pointer to that storage.

The .address is evaluated just before calling into native code when invoking a leaf Native external function. This ensures the Dart garbage collector will not move the object that the address points in to.

Available on T extends Union, provided by the UnionAddress<T extends Union> extension

Implementation

external Pointer<T> get address;