Re: problems compiling NSAnimation.m

[Richard Frith-Macdonald]

On 10 May 2007, at 12:35, Nicola Pero wrote:

> On May 8, 2007, at 11:14 PM, Riccardo wrote:
>
> > Hi,
> >
> > trying to compile NSAnimation on older compilers is a nightmare  
> > (like gcc 2.95). I fixed some trivial stuff, but then stopped: the  
> > main problem is the _NSANIMATION_LOCK macro. Since this macro  
> > defines a variable in it,
> >
> > #define _NSANIMATION_LOCK           \
> >   BOOL __gs_isLocked = NO;          \
> >   if (_isThreaded)                  \
> >   {                                 \
> >     __gs_isLocked = YES;            \
> >     NSDebugFLLog(@"NSAnimationLock",\
> >                  @"%@ LOCK %@",self,[NSThread currentThread]);\
> >     [_isAnimatingLock lock];        \
> >   }
> >
> >
> > it causes a hidden "c99-ism" everywhere. If the definition of  
> > __gs_isLocked inside the macron can be avoided or the macroitself  
> > can be avoided, I think the code would be cleaner.
>
>
> This looks pretty bad, not only because it doesn't compile with GCC  
> 2.95, but also because that variable defined in the middle of  
> nowhere is very ugly ... unclear
> scope (what happens if you have two _NSANIMATION_LOCK in  
> sequence ?  is the same variable being used or different  
> variables ?) ... ;-)

I fixed this to make __gs_isLocked an ivar rather than declaring it  
locally (which was pretty suboptimal).  I also fixed a bug in the  
unlock macro (it was setting the lag to the wrong value), and added  
assertions to check that the macro is not misused.

> Is there a flag we can pass to ask GCC to refuse c99-isms ?  There  
> must be one.

Not that I know of ... and I did look for it once before.

>   Shall we add this to the core library makefiles ?  That way we are
> more positive that the code should compile with 2.95 because nobody  
> will be able to commit c99-isms without breaking compilation with  
> all versions
> of GCC. :-)

I'd certainly like such a flag to be added if you can find one.