Re: So You Think You Can Const?

On 12/01/2025 11:22, Keith Thompson wrote:

Michael S <already5chosen@yahoo.com> writes:
[...]

Tried to read the old discussion. Didn't understand much.
But it strengthened my opinion: it's ridiculous. Standard would be way
better with this nonsense removed.
The function below should be guaranteed by standard to return 42.
int foo(void)
{
   char* a = malloc(100);
   if (!a) return 42;
   char* b = a + 42;
   free(a);
   return b - a;
}

 How exactly would that be useful?
 The intent, I think, is to allow for implementations that perform
checking when loading a pointer value.  It's possible that there
currently are no such implementations, but even so, how would
reading a free()d pointer value be useful?
 I'd say that passing a pointer value to free() means you no longer care
about it.
 

What if, after the free(a), you have ...
char *b = malloc(100);
... and the old address of 'a' gets reused.
Could you then carry on using 'a'?
You'd be relying on chance, and it'd be terribly bad form ... but would it be legal?