bool ptrlist_insert_last(PtrList **ptrlist, void *ptr)
{
PtrList *node=mknode(ptr);
bool ptrlist_insert_last(PtrList **ptrlist, void *ptr)
{
PtrList *node=mknode(ptr);
UNLINK_ITEM(*ptrlist, node, next, prev);
LINK_ITEM_LAST(*ptrlist, node, next, prev);
UNLINK_ITEM(*ptrlist, node, next, prev);
LINK_ITEM_LAST(*ptrlist, node, next, prev);
UNLINK_ITEM(*ptrlist, node, next, prev);
LINK_ITEM_FIRST(*ptrlist, node, next, prev);
UNLINK_ITEM(*ptrlist, node, next, prev);
LINK_ITEM_FIRST(*ptrlist, node, next, prev);