Re: issue with auto-enable of Menus

[Josh Freeman]

Hi Riccardo,

On Nov 13, 2017, at 5:24 AM, David Chisnall wrote:

> On 13 Nov 2017, at 08:17, Wolfgang Lux <wolfgang.lux@gmail.com> wrote:
> > While sel_isEqual is just an alias for == on Apple's runtime (and  
> > the GNUstep runtime, I assume), this need not be the case for other  
> > runtimes. In particular, for the old GNU runtime sel_isEqual is not  
> > equivalent to ==, as you've observed.
>
> It’s also not == on the GNUstep runtime, and can’t easily be with a  
> new ABI if we want it to work on ELF / COFF platforms.  Apple relies  
> on the run-time linker deduplicating their selector table and  
> inserting selectors into a contiguous region of memory.


   Note that Apple didn't add sel_IsEqual() to its runtime until OS X  
10.5; If you still want Graphos to support OS X 10.4 & earlier, you'll  
need to keep using '==' on Macs. One way to do this without #ifdefs  
around each selector comparison would be to use a macro:


#ifdef __APPLE__
#   define macroSelectorsAreEqual(selector1, selector2) (selector1 ==  
selector2)
#else // GNUstep
#   define macroSelectorsAreEqual(selector1, selector2)  
sel_isEqual(selector1, selector2)
#endif

...

if (macroSelectorsAreEqual(action, @selector(copy:))) {...


   (It's probably safe to assume Apple's runtime will continue  
supporting '==' for selector comparison, otherwise it would break a  
significant amount of legacy code).

Cheers,

Josh