On Wed, Jul 21, 2021 at 02:36:16PM +0200, Didier Kryn wrote:
> added (by gcc ?) to work around a missing feature of the C language:
> dynamic allocation on the stack. This lack has disapeared many years ago
> ( don't know with which version of the C standard) , with the following
> form of allocation:
>
> ...
>
> n = 2x+1;
>
> {
>
> int array[n];
>
> ...
>
> }
>
> And, therefore, alloca() should be removed.Well, alloca(n*sizeof(int)) and your suggestion both do the same in that they allocate memory from stack without any checking. Thus both will show the same failure mode of possible stack overflow. In any case, the implementation should put some limit on n before executing alloca() or int array[n]. To be honest, I really don't seesomething against using alloca() despite its not Posix. Especially, there is no advantage of array[n] regarding the stack overflow issue. Of course, critical software should not rely on dynamic stack allocation since its unpredictable. (but also not on runtime heap allocation too) cheers, Andreas -- gnuPG keyid: 8C2BAF51 fingerprint: 28EE 8438 E688 D992 3661 C753 90B3 BAAA 8C2B AF51
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