page_size_init (void)
{
  page_size = sysconf (_SC_PAGE_SIZE);
  assert (page_size > 0);
  assert (is_power_of_2 (page_size));
}
page_size_init (void)
{
  page_size = sysconf (_SC_PAGE_SIZE);
  assert (page_size > 0);
  assert (is_power_of_2 (page_size));
}