Explicitly indicates that a block in the group finished executing.
- iOS 4.0+
- macOS 10.6+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
The dispatch group to update. This parameter cannot be
Calling this function decrements the current count of outstanding tasks in the group. Using this function (with
enter()) 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
A call to this function must balance a call to
enter(). It is invalid to call it more times than
enter(), which would result in a negative count.