array-displacement array ⇒ displaced-to, displaced-index-offset
| array | an array. |
| displaced-to | an array or nil. |
| displaced-index-offset | a non-negative fixnum. |
If the array is a displaced array,
returns the values of the :displaced-to and :displaced-index-offset
options
for the array (see the functions make-array and adjust-array).
If the array is not a displaced array,
nil and 0 are returned.
If array-displacement is called on an array
for which a non-nil object was provided as the
:displaced-to argument to make-array
or adjust-array, it must return that object
as its first value. It is implementation-dependent
whether array-displacement returns a non-nil
primary value for any other array.
(setq a1 (make-array 5)) ⇒ #<ARRAY 5 simple 46115576>
(setq a2 (make-array 4 :displaced-to a1
:displaced-index-offset 1))
⇒ #<ARRAY 4 indirect 46117134>
(array-displacement a2)
⇒ #<ARRAY 5 simple 46115576>, 1
(setq a3 (make-array 2 :displaced-to a2
:displaced-index-offset 2))
⇒ #<ARRAY 2 indirect 46122527>
(array-displacement a3)
⇒ #<ARRAY 4 indirect 46117134>, 2
Should signal an error of type type-error if array is not an array.