description

# Isolate class Null safety

An isolated Dart execution context.

All Dart code runs in an isolate, and code can access classes and values only from the same isolate. Different isolates can communicate by sending values through ports (see ReceivePort, SendPort).

An `Isolate` object is a reference to an isolate, usually different from the current isolate. It represents, and can be used to control, the other isolate.

When spawning a new isolate, the spawning isolate receives an `Isolate` object representing the new isolate when the spawn operation succeeds.

Isolates run code in its own event loop, and each event may run smaller tasks in a nested microtask queue.

An `Isolate` object allows other isolates to control the event loop of the isolate that it represents, and to inspect the isolate, for example by pausing the isolate or by getting events when the isolate has an uncaught error.

The controlPort identifies and gives access to controlling the isolate, and the pauseCapability and terminateCapability guard access to some control operations. For example, calling pause on an `Isolate` object created without a pauseCapability, has no effect.

The `Isolate` object provided by a spawn operation will have the control port and capabilities needed to control the isolate. New isolate objects can be created without some of these capabilities if necessary, using the Isolate.Isolate constructor.

An `Isolate` object cannot be sent over a `SendPort`, but the control port and capabilities can be sent, and can be used to create a new functioning `Isolate` object in the receiving port's isolate.

## Constructors

Isolate(SendPort controlPort, {Capability? pauseCapability, Capability? terminateCapability})
  Create a new Isolate object with a restricted set of capabilities. [...]

## Properties

controlPort → SendPort
  Control port used to send control messages to the isolate. [...]
  final
debugName → String?
  The name of the Isolate displayed for debug purposes. [...]
  @Since("2.3"), read-only
errors → Stream
  Returns a broadcast stream of uncaught errors from the isolate. [...]
  read-only
hashCode → int
  The hash code for this object. [...]
  read-only, inherited
pauseCapability → Capability?
  Capability granting the ability to pause the isolate. [...]
  final
runtimeType → Type
  A representation of the runtime type of the object.
  read-only, inherited
terminateCapability → Capability?
  Capability granting the ability to terminate the isolate. [...]
  final

## Methods

addErrorListener(SendPort port) → void
  Requests that uncaught errors of the isolate are sent back to `port`. [...]
addOnExitListener(SendPort responsePort, {Object? response}) → void
  Requests an exit message on `responsePort` when the isolate terminates. [...]
kill({int priority: beforeNextEvent}) → void
  Requests the isolate to shut down. [...]
noSuchMethod(Invocation invocation) → dynamic
  Invoked when a non-existent method or property is accessed. [...]
  inherited
pause([Capability? resumeCapability]) → Capability
  Requests the isolate to pause. [...]
ping(SendPort responsePort, {Object? response, int priority: immediate}) → void
  Requests that the isolate send `response` on the `responsePort`. [...]
removeErrorListener(SendPort port) → void
  Stops listening for uncaught errors from the isolate. [...]
removeOnExitListener(SendPort responsePort) → void
  Stops listening for exit messages from the isolate. [...]
resume(Capability resumeCapability) → void
  Resumes a paused isolate. [...]
setErrorsFatal(bool errorsAreFatal) → void
  Sets whether uncaught errors will terminate the isolate. [...]
toString() → String
  Returns a string representation of this object.
  inherited

## Operators

operator ==(Object other) → bool
  The equality operator. [...]
  inherited

## Static Properties

current → Isolate
  Return an Isolate object representing the current isolate. [...]
  read-only
packageConfig → Future<Uri?>
  The package root of the current isolate, if any. [...]
  read-only
packageRoot → Future<Uri?>
  The location of the package configuration of the current isolate, if any. [...]
  @Deprecated('packages/ directory resolution is not supported in Dart 2.'), read-only

## Static Methods

resolvePackageUri(Uri packageUri) → Future<Uri?>
  Maps a package: URI to a non-package Uri. [...]
spawn<T>(void entryPoint(T message), T message, {bool paused: false, bool errorsAreFatal: true, SendPort? onExit, SendPort? onError, String? debugName}) → Future<Isolate>
  Creates and spawns an isolate that shares the same code as the current isolate. [...]
spawnUri(Uri uri, List<String> args, dynamic message, {bool paused: false, SendPort? onExit, SendPort? onError, bool errorsAreFatal: true, bool? checked, Map<String, String>? environment, Uri? packageRoot, Uri? packageConfig, bool automaticPackageResolution: false, String? debugName}) → Future<Isolate>
  Creates and spawns an isolate that runs the code from the library with the specified URI. [...]

## Constants

beforeNextEvent → const int
  Argument to `ping` and `kill`: Ask for action before the next event.
  `1`
immediate → const int
  Argument to `ping` and `kill`: Ask for immediate action.
  `0`