Core Location Reference

Complete API reference for modern Core Location (iOS 17+). Covers CLLocationUpdate, CLMonitor, CLServiceSession, CLBackgroundActivitySession, authorization patterns, and legacy API migration.

When to Use This Reference

Use this reference when you need:

• CLLocationUpdate AsyncSequence patterns
• CLMonitor geofencing implementation
• CLServiceSession declarative authorization (iOS 18+)
• CLBackgroundActivitySession for background updates
• Authorization state handling
• Legacy CLLocationManager migration patterns

For troubleshooting: See core-location-diag for location issues.

Example Prompts

Questions you can ask Claude that will draw from this reference:

• "How do I use CLLocationUpdate with async/await?"
• "What is CLMonitor and how do I set up geofencing?"
• "How do I implement CLServiceSession for authorization?"
• "What's the modern way to do background location updates?"
• "How do I handle the 20-geofence limit?"
• "What are the diagnostic properties on CLLocationUpdate?"
• "How do I migrate from CLLocationManager delegates?"

What's Covered

Modern APIs (iOS 17+)

• CLLocationUpdate with AsyncSequence
• LiveConfiguration options
• isStationary for automatic pause/resume
• CLMonitor for geofencing and beacons
• CircularGeographicCondition and BeaconIdentityCondition
• 20-condition limit management

CLServiceSession (iOS 18+)

• Declarative authorization goals
• fullAccuracyPurposeKey for temporary precision
• Implicit sessions from liveUpdates iteration
• Diagnostic properties (authorizationDenied, insufficientlyInUse)
• Session layering patterns

Background Location

• CLBackgroundActivitySession setup
• Background mode capability requirements
• App lifecycle through suspend/terminate
• Session recovery on relaunch

Authorization

• Authorization levels and state machine
• Accuracy authorization (full vs reduced)
• Required Info.plist keys
• Legacy requestWhenInUseAuthorization patterns

Legacy APIs (iOS 12-16)

• CLLocationManager delegate pattern
• Accuracy constants
• Region monitoring (deprecated)
• Significant location changes
• Visit monitoring

Key Pattern

iOS 17+ Location Updates

for try await update in CLLocationUpdate.liveUpdates() {
    if update.authorizationDenied {
        showLocationDeniedUI()
        break
    }
    if let location = update.location {
        processLocation(location)
    }
    if update.isStationary {
        // Updates pause automatically, resume when device moves
    }
}

iOS 17+ Geofencing

let monitor = await CLMonitor("MyApp")
let condition = CLMonitor.CircularGeographicCondition(
    center: CLLocationCoordinate2D(latitude: 37.33, longitude: -122.01),
    radius: 100
)
await monitor.add(condition, identifier: "ApplePark")

for try await event in monitor.events {
    switch event.state {
    case .satisfied: handleEntry(event.identifier)
    case .unsatisfied: handleExit(event.identifier)
    case .unknown: break
    }
}

Documentation Scope

This page documents the axiom-core-location-ref reference skill—complete API coverage Claude uses when you need specific Core Location APIs or implementation patterns.

For architecture decisions: See core-location for when to use different monitoring approaches.

For troubleshooting: See core-location-diag for debugging location issues.

Related

• core-location — Authorization and monitoring strategy decisions
• core-location-diag — Location troubleshooting
• energy-ref — Location as battery subsystem

Resources

WWDC: 2023-10180 (CLLocationUpdate), 2023-10147 (CLMonitor), 2024-10212 (CLServiceSession)

Docs: /corelocation, /corelocation/clmonitor, /corelocation/cllocationupdate, /corelocation/clservicesession