An identifier you use to distinguish between signposts that have the same name and destination log.
- iOS 12.0+
- macOS 10.14+
- Mac Catalyst 13.0+
- tvOS 12.0+
- watchOS 5.0+
- Xcode 10.0+
Multiple intervals with matching log objects and interval names can be in-flight simultaneously. In order for data-processing tools to correctly match the beginning and end of an interval, you need to identify each interval with a unique signpost identifier. Use the first strategy in the list below that matches your use case:
If you can guarantee that intervals with the same log and name can never overlap in time, specify
exclusiveas the signpost ID.
If you already have your own integer data that can uniquely identify each instance of the task being measured, instantiate the signpost ID using the
init(_:)method. The value must not match one of the predefined signpost values.
If you have a pointer that can uniquely identify begin/end pairs (such as a pointer to a data object used by the code being measured), instantiate the signpost ID using the
init(log:method. Don't use this initializer for signposts that span process boundaries.
Otherwise, instantiate a signpost ID using the
init(log:)method each time you create signposts for a discrete task you want to track.