.. _cancelling_nested_parallelism:

Canceling Nested Parallelism

Nested parallelism is canceled if the inner context is bound to the outer context; otherwise it is not.

If the execution of a flow graph is canceled, either explicitly or due to an exception, any tasks started by parallel algorithms or flow graphs nested within the nodes of the canceled flow graph may or may not be canceled.

As with all of the library's nested parallelism, you can control cancellation relationships by use of explicit task_group_context objects. If you do not provide an explicit task_group_context to a flow graph, it is created with an isolated context by default.