# OSSignposter An object for measuring task performance using the unified logging system. ``` struct OSSignposter ``` ## Overview Signposts allow you to record meaningful information about the duration of your app’s tasks using the same subsystems and categories that you use for logging. Use `OSSignposter` to create signposted intervals in your code, and then use Instruments’ `os_signposts` instrument to record those intervals as you run your app and perform the actions to measure. Instruments displays signpost data visually in a timeline.  To add a signposted interval, create a signpost ID — an identifier that disambiguates intervals that have the same name, subsystem, and category, and that exist within the same scope — and then add a call to one of the class’s `beginInterval` methods just before the code you want to measure. Retain the interval state it returns, and end the interval by passing that state to one of the class’s `endInterval` methods, which you call immediately after the measured code. A signposter uses interval state to enforce a number of runtime assertions, the behavior of which depends on your app’s build configuration. For more information, see [`OSSignpostIntervalState`](/documentation/os/OSSignpostIntervalState). A signposted interval consists of one begin call and one end call only. `OSSignposter` also provides functionality to signpost a closure, and to emit individual signposts that don’t have a duration that you can use to highlight points of interest, such as when the user taps a button or performs a specific gesture. ## Topics ### Creating a Signposter [`init()`](/documentation/os/OSSignposter/init()) Creates a signposter that uses the default subsystem. [`init(subsystem:category:)`](/documentation/os/OSSignposter/init(subsystem:category:)-94xpb) Creates a signposter that uses the specified subsystem and category. [`init(subsystem:category:)`](/documentation/os/OSSignposter/init(subsystem:category:)-4vdri) Creates a signposter that uses the specified subsystem and system-defined log category. [`init(logger:)`](/documentation/os/OSSignposter/init(logger:)) Creates a signposter that uses the subsystem and category of an existing logger. [`init(logHandle:)`](/documentation/os/OSSignposter/init(logHandle:)) Creates a signposter that uses the subsystem and category of an existing log. [`disabled`](/documentation/os/OSSignposter/disabled) A shared signposter that doesn’t emit signposts at runtime. ### Getting State [`isEnabled`](/documentation/os/OSSignposter/isEnabled) A Boolean value that indicates whether the signposter can emit signposts. ### Generating Signpost IDs [`makeSignpostID()`](/documentation/os/OSSignposter/makeSignpostID()) Returns an identifier that’s unique within the scope of the signposter. [`makeSignpostID(from:)`](/documentation/os/OSSignposter/makeSignpostID(from:)) Returns an identifier that the signposter derives from the specified object. [`OSSignpostID`](/documentation/os/OSSignpostID) An identifier that disambiguates signposted intervals. ### Starting a Signposted Interval [`beginInterval(_:id:)`](/documentation/os/OSSignposter/beginInterval(_:id:)) Begins a signposted interval. [`beginInterval(_:id:_:)`](/documentation/os/OSSignposter/beginInterval(_:id:_:)) Begins a signposted interval and attaches the specified message. [`beginAnimationInterval(_:id:)`](/documentation/os/OSSignposter/beginAnimationInterval(_:id:)) Begins a signposted interval for measuring an animation. [`beginAnimationInterval(_:id:_:)`](/documentation/os/OSSignposter/beginAnimationInterval(_:id:_:)) Begins a signposted interval for measuring an animation, and attaches a message. [`OSSignpostIntervalState`](/documentation/os/OSSignpostIntervalState) An object that tracks the state of a signposted interval. [`SignpostMetadata`](/documentation/os/SignpostMetadata) The type that represents a message you attach to a signpost. ### Stopping a Signposted Interval [`endInterval(_:_:)`](/documentation/os/OSSignposter/endInterval(_:_:)) Ends the signposted interval that corresponds to the specified name and state. [`endInterval(_:_:_:)`](/documentation/os/OSSignposter/endInterval(_:_:_:)) Ends a signposted interval and attaches the specified message. ### Measuring a Closure [`withIntervalSignpost(_:id:around:)`](/documentation/os/OSSignposter/withIntervalSignpost(_:id:around:)) Measures the execution of the specified closure. [`withIntervalSignpost(_:id:_:around:)`](/documentation/os/OSSignposter/withIntervalSignpost(_:id:_:around:)) Measures the execution of a closure and attaches the specified message. ### Emitting Individual Signposts [`emitEvent(_:id:)`](/documentation/os/OSSignposter/emitEvent(_:id:)) Marks a point of interest in time. [`emitEvent(_:id:_:)`](/documentation/os/OSSignposter/emitEvent(_:id:_:)) Marks a point of interest in time and attaches the specified message. ## Relationships ### Conforms To [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Sendable`](/documentation/Swift/Sendable) --- Copyright © 2026 Apple Inc. 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