[Mesa-dev] exec_list question

[Timothy Arceri]

I just tried the below code which is much cleaner but it to causes the
original list to lose the last node. 

exec_node *node = type->array_specifier->array_dimensions.head->next;
for (/* nothing */; !node->is_tail_sentinel(); node = node->next) {
   array_specifier->array_dimensions.push_tail(node);
}

I originally thought the pointer was being freed by an access to the
copied list somewhere but since foreach_list_safe makes things work
there must be something else happening.


On Sun, 2014-01-12 at 19:08 +1100, Timothy Arceri wrote:
> Hi Guys,
> 
> I've been chasing my tail most of the afternoon using exec_list
> basically I was just trying to copy all but the first element from one
> list to another using the code bellow. 
> 
>             exec_list *copy_dims =
> &type->array_specifier->array_dimensions;
>             int i = 0;
>             //TODO: has to be better way to copy all dimension but the
> first one
>             foreach_list (node, copy_dims) {
>                if(i>0)
>                   array_specifier->array_dimensions.push_tail(node);
>                i++;
>             }
> 
> But when doing this the last element from the list I was coping FROM was
> somehow being lost.
> 
> Replacing foreach_list with foreach_list_safe seems to have fixed the
> problem. However I don't really understand why is someone able to
> explain to me what's happening here?
>