Creates a new group to which you can assign block objects.
- iOS 4.0+
- macOS 10.6+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The newly created group, or
NULL on failure.
This function creates a new group with which block objects can be associated (by using the
dispatch function). The dispatch group maintains a count of its outstanding associated tasks, incrementing the count when a new task is associated and decrementing it when a task completes. Functions such as
dispatch use that count to allow your application to determine when all tasks associated with the group have completed. At that time, your application can take any appropriate action.