XmListDeleteItemsPos man page
XmListDeleteItemsPos — A List function that deletes items from the list starting at the given position
#include <Xm/List.h> void XmListDeleteItemsPos( Widget widget, int item_count, int position);
XmListDeleteItemsPos deletes the specified number of items from the list starting at the specified position.
Specifies the ID of the List from whose list an item is deleted.
Specifies the number of items to be deleted. This number must be nonnegative.
Specifies the position in the list of the first item to be deleted. A value of 1 indicates that the first deleted item is the first item in the list; a value of 2 indicates that it is the second item; and so on.
For a complete definition of List and its associated resources, see XmList(3).