PVS-Studio warning V205 for TortoiseSVN

static int cmpforsearch(void *av, void *bv)
{
  Actual_Socket b = (Actual_Socket) bv;
  unsigned long as = (unsigned long) av,
                bs = (unsigned long) b->s;
  if (as < bs)
    return -1;
  if (as > bs)
    return +1;
  return 0;
}

This suspicious code was found in TortoiseSVN project by PVS-Studio static code analyzer.
Warning message is:
V205 Explicit conversion of pointer type to 32-bit integer type: (unsigned long) av winnet.c 139

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