[cfe-dev] Detecting ARC via #if(def)?

[Eli Friedman]

On Mon, Jun 13, 2011 at 8:45 AM, marc hoffman <mh at elitedev.com> wrote:
> i'm hoping this is not NDA-covered, but with LLV/Clang itself being open
> source i assume it's not:
> at WWDC i was told there is a functionality in clang/LLVM to check for
> availability of specific features in general, and for whether the current
> code is being compiled with ARC or not, specifically, via an #if(def) - the
> goal being ro write a piece of code that can compile with and w/o ARC, by
> #if(def)ing a handful of retain/release calls.
> i was told this was well documented in the clang docs, but i've been unable
> to find anything regarding this - is anyone here aware of this featyre (and
> of the option to check for that represents ARC) and could point me into the
> right direction?

ARC hasn't landed in the public repository yet.

In terms of feature ifdefs, see
http://clang.llvm.org/docs/LanguageExtensions.html#feature_check .

-Eli