Bluetooth SIG have updated their Introduction to Bluetooth Beacons. It provides advice and examples how to use beacons from iOS, Android and Raspberry Pi using the respective Bluetooth APIs.
The examples show how to scan for AltBeacon which is unusual because most people will want to scan for iBeacon because AltBeacon is sent by very few beacons. This is less of a problem on Android and Raspberry Pi where slightly modified code can be used. However, on iOS, the suggested APIs won’t work for iBeacon because Apple removes the iBeacon data from the Bluetooth scan response data to force you to use the iBeacon specific APIs which aren’t mentioned in the guide.