Is this possible? I want the number of inches, not the number of pixels. I know it is approximately 160 ppi. But not exactly.
Maybe Jeff Hay's code can be adapted to include iPad Mini. The trick is to get the device's model identifier. The most recent non-retina iPad is "iPad2,4" and the first iPad mini is "iPad2,5". Now all you need to check is if the screen scaling is 1.0 (non-retina)
Although this code is not future-proof, you can always add more rules for model identifiers.
#import
#define SCREEN_SIZE_IPAD_MINI 7.9
struct utsname systemInfo;
uname(&systemInfo);
if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad && strcasecmp(systemInfo.machine, "iPad2,5") >= 0 [[UIScreen mainScreen] scale] == 1.0)
return SCREEN_SIZE_IPAD_MINI