Re: netapi32: Set the buffer to NULL in NetApiBufferFree

[Kai Blin]

On Thursday 26 June 2008 16:34:51 you wrote:
> @@ -52,6 +52,7 @@ NET_API_STATUS WINAPI NetApiBufferFree(LPVOID Buffer)
>  {
>      TRACE("(%p)\n", Buffer);
>      HeapFree(GetProcessHeap(), 0, Buffer);
> - Buffer = NULL;
> return NERR_Success;
>
> }
>
> I don't get it.  How does setting a local variable to NULL avoid a
> warning about freeing it twice?
>
> I'm not saying the patch is wrong, I'm just saying I don't get how
> Valgrind is tricked by this.

The trick is the test code.

From dlls/netapi32/tests/apibuf.c, lines 44-58

/* test normal logic */
    ok(pNetApiBufferAllocate(1024, (LPVOID *)&p) == NERR_Success,
       "Reserved memory\n");
    ok(pNetApiBufferSize(p, &dwSize) == NERR_Success, "Got size\n");
    ok(dwSize >= 1024, "The size is correct\n");

ok(pNetApiBufferReallocate(p, 1500, (LPVOID *) &p) == NERR_Success,
       "Reallocated\n");
    ok(pNetApiBufferSize(p, &dwSize) == NERR_Success, "Got size\n");
    ok(dwSize >= 1500, "The size is correct\n");

ok(pNetApiBufferFree(p) == NERR_Success, "Freed\n");

/* test errors handling */
    ok(pNetApiBufferFree(p) == NERR_Success, "Freed\n"); <-- valgrind warning

Which is to be expected. HeapFree on a NULL pointer doesn't hurt, though. As 
this test seems to work on Windows, that seemed like the quickest fix.

Cheers,
Kai