Re: Stupid objective-c question
Re: Stupid objective-c question
- Subject: Re: Stupid objective-c question
- From: Alastair Houghton <email@hidden>
- Date: Tue, 27 Sep 2016 08:51:44 +0100
On 27 Sep 2016, at 05:31, Britt Durbrow <email@hidden> wrote:
>
> FWIW, it’s currently an implementation detail that SELs do map into the global address space in a way that doesn’t collide with anything else; but technically, they are in their own address space and the system could map them otherwise in a manner that does have collisions with other stuff.
That’s true. IIRC GNUStep SEL values don’t work the same way as they do with the Apple/NeXT runtime, so this trick wouldn’t work there.
> In practice, I don’t think that will ever happen, because a) too much existing code makes the assumption that a SEL is de-referenceable or otherwise depends on this implementation detail; and b) we have 64-bit addressing, so we’re not going to run out of address space such that making that change would be advantageous.
Agreed, it seems unlikely that Apple would change it; not impossible, but quite unlikely. As I say, relying on it means your code won’t straightforwardly port to GNUStep, but most of us don’t care too much about that.
Kind regards,
Alastair.
--
http://alastairs-place.net
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