Re: __has_feature() for nullability?

I'm not sure, but from what I've read, I believe the non-underscore version is only for use in Obj-C declarations (methods, properties), where the double-underscore is for C declarations, including functions and variables (local, global, or, I would expect, instance).

I don't know why there would be an issue with multiple levels of pointers in a method declaration. Perhaps when everyone's recovered from WWDC, someone else will chime in to help out. :-)

On 13 June 2015 at 18:00, Jonathan Schleifer <js-apple-objc@webkeks.org> wrote:

Ah, thanks, that indeed works :). I was grepping `strings clang` for objc_null, that explains why I didn't find anything.

Also, since there's no real documentation yet, what's the difference between __nullable and nullable and __nonnull and nonnull? What I found online reads like it's basically the same, with the one without the __ being only usable in a method declaration. However, I noticed that there are cases where the one without __ doesn't work in a method declaration, e.g. when you have two layers of pointers.

--
Jonathan

> Am 13.06.2015 um 17:59 schrieb Michael Hackett <mhackett@randomsample.org>:
>
> I believe it's:
>
>     #if
>  __has_feature(nullability)
>
>
>
> On 13 June 2015 at 11:54, Jonathan Schleifer <js-apple-objc@webkeks.org> wrote:
> Hi!
>
> I saw that there's a __has_feature() for objc_generics and objc_kindof, however, there doesn't seem to be objc_nullability or similar. Since the sources for the Clang from Xcode 7 haven't been released, I grepped through `strings clang`, however, I could not find anything useful.
>
> What is the best way to check if the compiler supports nullability, so that if not I can #define nonnull and friends to nothing?
>
> PS: I also found objc_generics_variance - what's that?
>
> --
> Jonathan

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