iPhones OS: how to programmatically differentiate iPad 3G from iPad Wi-Fi? - iphone

Question

Is there any property or other mechanism in iPhone OS to check during runtime whether application is running on iPad 3G or iPad Wi-Fi?
Seems like UIDevice class does not provide anything like that.
My application is using internet access extensively and I would like to explicitly warn user that on 3G delays or additional costs can be expected OR even ban application from running on iPad 3G with some fancy popup.

Answer 1

I assume that other than 3G networking capabilities, there is no need to make a difference. Using Reachability.h class provided by Apple you can check if internet connection is available and if it is Mobile network or Wireless network.
Sample code here:
http://developer.apple.com/iphone/library/samplecode/Reachability/Introduction/Intro.html
The Reachability class provides the following values:
ReachableViaCarrierDataNetwork, ReachableViaWiFiNetwork or NotReachable.

Answer 2

You can differentiate between WiFi and 3G iPads if your app is running on a second generation iPad:
+ (NSString *) iPadModelName
{
size_t size;
sysctlbyname("hw.machine", NULL, &size, NULL, 0);
char *machine = malloc(size);
sysctlbyname("hw.machine", machine, &size, NULL, 0);
NSString *platform = [NSString stringWithCString:machine encoding:NSASCIIStringEncoding];
free(machine);
if ([platform isEqualToString:#"iPad2,1"]) return #"iPad 2 (WiFi)";
if ([platform isEqualToString:#"iPad2,2"]) return #"iPad 2 (GSM)";
if ([platform isEqualToString:#"iPad2,3"]) return #"iPad 2 (CDMA)";
return platform;
}