[pacman-dev] [BUG] alpm_list_remove need an initalized pointer for void **data

[Dan McGee]

On Thu, Aug 7, 2008 at 10:23 AM, solsTiCe d'Hiver
<solstice.dhiver at gmail.com> wrote:
> for me it is a problem with alpm_list_remove but i am not an expert.
>
> look at this
> #include <alpm.h>
>
> int compare_int(const void *a, const void *b) {
>    const int* ia = (const int *)a;
>    const int* ib = (const int *)b;
>    return (*ia > *ib) - (*ia < *ib);
> }
>
> int main(void) {
>    alpm_list_t *l=NULL;
>    int a=2,a2=2;
>    l= alpm_list_add(l, &a);
>    l= alpm_list_add(l, &a2);
>    void **data=NULL;
>    l = alpm_list_remove(l, &a, compare_int, data);
>    puts("still ok ?");
>    void **data2;
>    l = alpm_list_remove(l, &a2, compare_int, data2);
>    return 0;
> }
>
> it only seg fault at the second alpm_list_remove

OK, you've found a much better test case here, thanks. This points us
to line 302, the NULL set below:

  if(data) {
    *data = NULL;
  }

This check doesn't seem quite right- shouldn't we be checking *data
for existance before we go setting things? Something like:

if(data && *data) {
  *data = NULL;
}

Or what do we do here? Double pointers start confusing me. :)

-Dan