How to detect iPhone OS version using macros

Question

I would like to detect iPhone OS version in my app. I have tried using detection code but was advised to use macros. Does someone experience, can you post sample code, and what library to use.

Answer 1

I am not certain what macros you are being advised to use. I always thought that the standard way to find the version number so that it will be compatiable with future and previous versions was to use

NSString* versionNumber = [[UIDevice currentDevice] systemVersion]

which gives it as a NSString such as @"2.0" or @"2.2.1"

There are the Version constants that describe the version of Foundation classes being used, with NSFoundationVersionNumber but I am uncertain of how reliable this will be in older and future code.