whereami.go

package main

import (

/*
#cgo CFLAGS: -x objective-c
#cgo LDFLAGS: -framework Foundation -framework CoreLocation
#import <CoreLocation/CoreLocation.h>

@interface WhereAmI : NSObject <CLLocationManagerDelegate>

+(WhereAmI *) instance;

@property (strong, nonatomic) CLLocationManager *locationManager;
@property (assign, nonatomic) BOOL searching;
@property (strong, nonatomic) CLLocation *currentLocation;

@end


@implementation WhereAmI

+(WhereAmI *) instance
{
    static WhereAmI *instance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        instance = [[self alloc]init];
    });
    return instance;
}

- (id)init {
    self = [super init];
    if(self != nil) {
        self.searching = true;
        self.locationManager = [[CLLocationManager alloc] init];
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        self.locationManager.distanceFilter = kCLDistanceFilterNone;
        self.locationManager.delegate = self;
        [self.locationManager startUpdatingLocation];
    }
    return self;
}

- (void)locationManager:(CLLocationManager *)manager
        didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    switch (status) {
        case kCLAuthorizationStatusAuthorized:
            [self.locationManager startUpdatingLocation];
            break;

        case kCLAuthorizationStatusDenied:
            NSLog(@"Location Services are denied");
            self.searching = false;
            break;

        case kCLAuthorizationStatusNotDetermined:
            [self.locationManager startUpdatingLocation];
            [self.locationManager stopUpdatingLocation];
            break;

        case kCLAuthorizationStatusRestricted:
            NSLog(@"Location services are restricted");
            self.searching = false;
            break;

        default:
            break;
    }
}

- (void)locationManager:(CLLocationManager *)manager
       didFailWithError:(NSError *)error
{
    NSLog(@"Location service failed with error %@", error);
    self.searching = false;
}

- (void)locationManager:(CLLocationManager *)manager
     didUpdateLocations:(NSArray*)locations
{
    self.currentLocation = [locations lastObject];
    self.searching = false;
}
@end

typedef struct {
    // latitude in degrees
    double latitude;
    // longitude in degrees
    double longitude;
    // altitude in meters
    double altitude;
    // radius of uncertainty for latitude/longitude, in meters
    double horizontalAccuracy;
    // accuracy of the altitude, in meters
    double verticalAccuracy;
    // epoch timestamp
    long timestamp;
} Location;

Location *whereAmI() {
    while([WhereAmI instance].searching) {
        CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.0, true);
    }
    CLLocation *cllocation = [WhereAmI instance].currentLocation;
    Location *location = malloc(sizeof(Location));
    location->latitude = cllocation.coordinate.latitude;
    location->longitude = cllocation.coordinate.longitude;
    location->altitude = cllocation.altitude;
    location->horizontalAccuracy = cllocation.horizontalAccuracy;
    location->verticalAccuracy = cllocation.verticalAccuracy;
    location->timestamp = cllocation.timestamp.timeIntervalSince1970 * 1000.0;
    return location;
}

*/
    "C"
    "fmt"
)

func main() {
    location := C.whereAmI()
    fmt.Printf("location: %v\n", location)
}