Re: realloc() - frequency, conditions, or experiences about relocation?

Phil Carmody <pc+usenet@asdf.org> writes:

Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

Suppose you do something like:
>
    some_type *p = malloc(BIG_VALUE);
    // ...
    p = realloc(p, SMALL_VALUE);
>
...  If realloc() succeeds and *does* relocate the object, p
still points to memory that has now been deallocated, and you don't have
a pointer to the newly allocated memory.

>
Surely some mistake?

Yes, and thanks for catching it.

If realloc() succeeds, p points to the newly allocated memory; you no
longer have a pointer to the old deallocated memory, but that's a good
thing.

I think I was describing the behavior of calling realloc(p, SMALL_VALUE)
without assigning the result to anything.

However, such self-assignments are bad for the reasons you state later;
verify, then update.

Right.

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */