返回从接收器坐标到指定位置坐标的距离（以米为单位）。

Returns the distance (in meters) from the receiver’s coordinate to the coordinate of the specified location.

// Deprecated in iOS 3.2 method
- (CLLocationDistance)getDistanceFrom:(const CLLocation *)location

// Correct method
- (CLLocationDistance)distanceFromLocation:(const CLLocation *)location

CLLocation