# addTaskUnlessCancelled(executorPreference:priority:operation:) Adds a child task to the group, unless the group has been canceled. Returns a boolean value indicating if the task was successfully added to the group or not. ``` mutating func addTaskUnlessCancelled(executorPreference taskExecutor: (any TaskExecutor)? = nil, priority: TaskPriority? = nil, operation: sending @escaping @isolated(any) () async -> ChildTaskResult) -> Bool ``` ## Parameters `taskExecutor` The task executor that the child task should be started on and keep using. Explicitly passing `nil` as the executor preference is equivalent to calling the `addTaskUnlessCancelled` method without a preference, and effectively means to inherit the outer context’s executor preference. You can also pass the [`globalConcurrentExecutor`](/documentation/Swift/globalConcurrentExecutor) global executor explicitly. `priority` The priority of the operation task. Omit this parameter or pass `nil` to inherit the task group’s base priority. `operation` The operation to execute as part of the task group. ## Return Value `true` if the child task was added to the group; otherwise `false`. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)