location

Where the device is — once, or continuously while the app is in use.

[dependencies]
location    = "*"
permissions = "*"
stdlib      = "*"

Use cpc pm add . location to write the platform-specific dependency closure.

import "location/location" as loc;
import "stdlib/result" as result;

fn got(f: loc::Fix, ctx: *u8) {
    // A failed or timed-out request arrives here too, with a negative
    // accuracy. Check before you read the coordinate.
    if !f.is_valid() { return; }
    say("${f.latitude}, ${f.longitude}  ±${f.accuracy_m}m");
}

let outcome = loc::once(on_fix: got);

A stream is the same call with a handle you keep:

match loc::updates(on_fix: got, request: loc::Request::new(accuracy: loc::Accuracy::Fine)) {
    result::Result::Ok(u) => { STREAM = u; }   // stops on drop
    result::Result::Err(e) => { }
}

Scope

Foreground only. One fix, or a stream while the person is using the app. It uses CoreLocation on Apple, Android's LocationManager, and GeoClue2 on Linux. The current Windows backend reports Unsupported. It does not do background tracking or a service that outlives the app — those are Android-shaped, have no iOS equivalent, and would need a typed foreground service and an "always" grant that Android 10+ will not even prompt for.

• tutorial — a working screen in ten minutes
• guide — permissions, accuracy, and the traps per platform
• ref — every type and verb

Tests

Unit tests live in src/test_main.cplus; both halves build together so the seam is linked rather than assumed.

cd vendor/location && cpc test

The Apple and Android live paths need a device or simulator — see the probes under playground/locationprobe_{mac,ios,android}. Linux needs a running GeoClue2 service and its desktop authorization agent.