CALL PEMST (STRID)
EMPTY STRUCTURE destroys all elements in structure STRID. Even when empty, the structure continues to exist and all the references made to it continue to exist.
If STRID is the open structure, all its elements are destroyed and element pointer is set to zero. If STRID does not designate any existing structure, then EMPTY STRUCTURE creates a new empty structure.
open structure, set element pointer, delete element, delete element range, delete element between labels