OS X version checking in Cocoa

Question

I am developing a Cocoa application and need to check whether the current OS X version is OS X 10.6 Snow Leopard

If the current version is Snow Leopard, I need to close the application with an error alert.

How can I find the current OS X version?

Answer 1

The relevant Apple documentation can be found in Using SDK-Based Development: Determining the Version of a Framework.

They suggest either testing the existence of a specific class or method or to check the framework version number, e.g. NSAppKitVersionNumber or NSFoundationVersionNumber. The relevant frameworks also declare a number of constants for different os versions (NSApplication constants, Foundation Constants).

The relevant code can be as simple as:

if (floor(NSAppKitVersionNumber) > NSAppKitVersionNumber10_5) {
    // Code for 10.6+ goes here
}