On Sun, Apr 20, 2014 at 02:43:53PM +0200, FRIGN wrote:
> On Sun, 20 Apr 2014 13:53:33 +0200
> Alexander Huemer <alexander.hue...@xx.vu> wrote:
>
> > > […]
> > > -#define LEN(a) (sizeof(a) / sizeof(a[0]))
> > > +#define LEN(a) (sizeof(a) / sizeof(a)[0])
> > > […]
> >
> > Why parenthesis anyway? a[0] is an expression, not a type, and there is
> > nothing to group here. sizeof is not a function!
>
> #define LEN(a) (sizeof a / sizeof *a)
>
> is the right way to do it.
You are missing the parentheses there.
Your macro provides the wrong answer for something like:
int a[] = { 1, 2, 3, 4, 5 };
printf("%zu\n", LEN(a + 2));
Cheers,
sin
