ist must
 * not be empty.
 *
 * See also: DList_FreeTail()
 */
/*************************************************************************/
/*
 * DList_FreeHead: Remove first element from list and free it.
 * The list must not be empty.
 *
 * See also: DList_RemoveHead()
 */
/*************************************************************************/
/*
 * DList_FreeTail: Remove last element from list and free it.
 * The list must not be empty.
 *
 * See also: DList_RemoveTail()
 */
/*************************************************************************/
/*
 * DList_SwapElems: Swap positions of given elements 'lhs' and 'rhs'.
 * Both elements must be linked, and must belong to same list.
 */
/*************************************************************************/
/*
 * DList_Clear: Clear whole list and free all elements.
 *
 * See also: DList_Init
 */
/*************************************************************************/
/*
 * DList_Traverse: Iterate over all elements in list from first to last.
 * Call given function func(head, elem) for each element. The function has
 * to return the next element in list to traverse, normally this is
 * DList_Next(elem).
 *
 * See also: TK_DLIST_FOREACH, TK_DLIST_FOREACH_REVERSE
 */
/*************************************************************************/
/*
 * DList_First: Return pointer of first element in list, maybe it's NULL.
 */
/*************************************************************************/
/*
 * DList_Last: Return pointer of last element in list, maybe it's NULL.
 */
/*************************************************************************/
/*
 * DList_Next: Return pointer of next element after 'elem', maybe it's NULL.
 *
 * See also: DList_Prev()
 */
/*************************************************************************/
/*
 * DList_Prev: Return pointer of previous element before 'elem', maybe it's
 * NULL.
 *
 * See also: DList_Next()
 */
/*************************************************************************/
/*
 * DList_IsEmpty: Test whether given list is empty.
 */
/*************************************************************************/
/*
 * DList_IsLinked: Test whether given element is linked.
 */
/*************************************************************************/
/*
 * DList_IsFirst: Test whether given element is first element in list.
 * Note that 'elem' must be linked.
 *
 * See also: DList_IsLast(), DList_IsLinked()
 */
/*************************************************************************/
/*
 * DList_IsLast: Test whether given element is last element in list.
 * Note that 'elem' must be linked.
 *
 * See also: DList_IsFirst(), DList_IsLinked()
 */
/*************************************************************************/
/*
 * DList_Size: Count number of elements in given list.
 */
/*************************************************************************/
/*
 * TK_DLIST_FOREACH: Iterate over all elements in list from first to last.
 * 'var' is the name of the variable which points to current element.
 *
 * See also: TK_DLIST_FOREACH_REVERSE, DList_Traverse()
 */
/*************************************************************************/
/*
 * TK_DLIST_FOREACH_REVERSE: Iterate over all elements in list from last
 * to first (backwards). 'var' is the name of the variable which points to
 * current element.
 */
/*************************************************************************/