Preprocessor macro for Apple Watch?

Question

I was looking at Apple\'s Lister (for Apple Watch, iOS, and OS X) sample. The sample performs a test for iOS and OS X:

#import 

#if          


        

Answer 1

There is no WatchKit or app extension target conditional. But you can create your own per-target conditionals that you use in the same way.

If you look in the "Build Settings" section for any target, there's a section called "Other C Flags". Add an entry for the WatchKit target. If you add something like -DMY_WATCHKIT_FLAG=1, you can then do #if MY_WATCHKIT_FLAG in code.

Make your custom flag, well, custom. It's not impossible that Apple might add a flag in the future called something like TARGET_WATCH_APP or whatever. Use a prefix on the flag name to make it specific to you.

Answer 2

With the current WatchKit SDK, all code in a Watch application runs on the phone it’s paired with, so there’s no point at which your preprocessor is going to encounter code that’s going to run on the Watch and thus not much use for a macro to tell it what to do when it does. The code in the ListerWatch target of the sample you linked to will run as an extension on the iPhone and talk to its watch UI via WatchKit.

Answer 3

As of watchOS 2.0, you can run native code on the watch, so this is a more relevant question.

I'm using the first early beta of watchOS 2, so this may change, but right now, TARGET_OS_WATCH is set to 1 on watchOS.

(Also, be careful: TARGET_OS_IPHONE is also set to 1 on watchOS, though TARGET_OS_IOS is 0.)

Answer 4

You can find all kind of target conditionals in the TargetConditionals.h (cmd + shift + o and type TargetConditionals.h).

In this list you can find a list like this and many more useful defines. Currently it does contain TARGET_OS_WATCH since WatchOS 2. For WatchOS 1 it was not possible to run custom code on the watch so it was not needed back then since everything ran on the phone itself.

#define TARGET_OS_MAC               1
#define TARGET_OS_WIN32             0
#define TARGET_OS_UNIX              0
#define TARGET_OS_IPHONE            1 
#define TARGET_OS_IOS               0
#define TARGET_OS_WATCH             1
#define TARGET_OS_TV                0
#define TARGET_OS_SIMULATOR         0
#define TARGET_OS_EMBEDDED          1 

Swift Addition

#if os(watchOS)
    [Watch code]
#else
    [Code for iOS, appleTV, or any else clause]
#endif

Some other valid values: iOS, OSX, tvOS

A small explanation about this and more http://nshipster.com/swift-system-version-checking/

At the bottom of this document https://developer.apple.com/library/ios/documentation/Swift/Conceptual/BuildingCocoaApps/InteractingWithCAPIs.html#//apple_ref/doc/uid/TP40014216-CH8-XID_15#Build Configurations Under the section 'Build Configurations' you can find a (hopefully) up to date list with all these values that are currently available