Re: Missed warning (-Wuse-after-free)

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

On 2023-02-17 08:44, David Malcolm wrote:
> This is possibly a silly question, but what *are* these safe
> alternatives? [1] How does one test to see if an object has been
> reallocated?

Oops sorry, I snipped off that part when pasting from the man page. 
Typically such conditionals are used to update pointers within structs 
(and in some overly adventurous cases, continue using the old pointer!) 
and the alternative is to save offsets in structs and not pointers.

The text I missed quoting here:

"""
         void adjust_pointers (int**, int);

         void grow (int **p, int n)
         {
           int **q = (int**)realloc (p, n *= 2);
           if (q == p)
             return;
           adjust_pointers ((int**)q, n);
         }

To avoid the warning at this level, store offsets into allocated memory 
instead of pointers.  This approach obviates needing to adjust the 
stored pointers after reallocation.
"""

Sid

> Dave
> [1] Would suggesting "rust" here be too snarky? :-P

I think the equivalent American expression is "lets take this outside" ;)