Gio.Task.set_return_on_cancel

### Method

# Gio Taskset_return_on_cancel

since: 2.36

#### Declaration

    gboolean
    g_task_set_return_on_cancel (
      GTask* task,
      gboolean return_on_cancel
    )

#### Description

Sets or clears `task`‘s return-on-cancel flag. This is only meaningful for tasks run via `g_task_run_in_thread()` or g_task_run_in_thread_sync().

If `return_on_cancel` is `TRUE`, then cancelling `task`‘s `GCancellable` will immediately cause it to return, as though the task’s `GTaskThreadFunc` had called `g_task_return_error_if_cancelled()` and then returned.

This allows you to create a cancellable wrapper around an uninterruptible function. The `GTaskThreadFunc` just needs to be careful that it does not modify any externally-visible state after it has been cancelled. To do that, the thread should call `g_task_set_return_on_cancel()` again to (atomically) set return-on-cancel `FALSE` before making externally-visible changes; if the task gets cancelled before the return-on-cancel flag could be changed, `g_task_set_return_on_cancel()` will indicate this by returning `FALSE`.

You can disable and re-enable this flag multiple times if you wish. If the task’s `GCancellable` is cancelled while return-on-cancel is `FALSE`, then calling `g_task_set_return_on_cancel()` to set it `TRUE` again will cause the task to be cancelled at that point.

If the task’s `GCancellable` is already cancelled before you call g_task_run_in_thread()/g_task_run_in_thread_sync(), then the `GTaskThreadFunc` will still be run (for consistency), but the task will also be completed right away.

Available since: 2.36

#### Parameters

`return_on_cancel`

  Type: `gboolean`

  Whether the task returns automatically when it is cancelled.

#### Return value

Type: `gboolean`

`TRUE` if `task`‘s return-on-cancel flag was changed to match `return_on_cancel`. `FALSE` if `task` has already been cancelled.