Explicitly indicates that a block has entered the group.
- iOS 4.0+
- macOS 10.6+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The dispatch group to update. This parameter cannot be
Calling this function increments the current count of outstanding tasks in the group. Using this function (with
dispatch) allows your application to properly manage the task reference count if it explicitly adds and removes tasks from the group by a means other than using the
dispatch function. A call to this function must be balanced with a call to
dispatch. You can use this function to associate a block with more than one group at the same time.