gio:task-check-cancellable (task)

task -- a g:task instance
cancellable -- a boolean whether task will check the state of its g:cancellable instance for you

The g:task-check-cancellable function gets the check-cancellable flag of task. The (setf g:task-check-cancellable) function sets or clears the check-cancellable flag. If this is true, the default, then the g:task-propagate-pointer function, etc, and the g:task-had-error function will check the g:cancellable instance of task first, and if it has been cancelled, then they will consider the task to have returned an "Operation was cancelled" error, regardless of any other error or return value the task may have had.

If cancellable is false, then task will not check the cancellable itself, and it is up to the owner of task to do this, for example using the g:task-return-error-if-cancelled function.

If you are using the g:task-set-return-on-cancel function as well, then you must leave cancellable set true.