sraSpanListCreate(void) {
  sraSpanList *item = (sraSpanList*)malloc(sizeof(sraSpanList));
  if (!item) return NULL;
  item->front._next = &(item->back);
  item->front._prev = NULL;
  item->back._prev = &(item->front);
  item->back._next = NULL;
  return item;
}
sraSpanListCreate(void) {
  sraSpanList *item = (sraSpanList*)malloc(sizeof(sraSpanList));
  if (!item) return NULL;
  item->front._next = &(item->back);
  item->front._prev = NULL;
  item->back._prev = &(item->front);
  item->back._next = NULL;
  return item;
}