[vlc-devel] [RFC v4] vlc_vector: add helpers for vectors

[Rémi Denis-Courmont]

Le perjantaina 31. elokuuta 2018, 22.48.17 EEST Romain Vimont a écrit :
> On Fri, Aug 31, 2018 at 06:46:05PM +0300, Rémi Denis-Courmont wrote:
> > Le perjantaina 31. elokuuta 2018, 15.04.52 EEST Romain Vimont a écrit :
> > > +#define vlc_vector_realloc_(pv, newsize) \
> > > +( \
> > > +    vlc_vector_reallocarray_((void **) &(pv)->data, newsize, \
> > > +                             sizeof(*(pv)->data)) && \
> > 
> > I strongly suspect a violation of type aliasing with the cast to void **.
> 
> I agree that this looks suspicious regarding the strict aliasing rules:
> a pointer to type* (type**) is deferenced via a pointer to void*
> (void**).
> 
> The standard says:
> > An object shall have its stored value accessed only by an lvalue
> > expression that has one of the following types:
> >  - a type compatible with the effective type of the object,

I know what strict aliasing is.

> I'm not sure about the definition of "compatible", but I would say that
> type* and void* are compatible types.

No, unless type is void, they are not.

-- 
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