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array-total-size-limit

array-total-size-limit Constant Variable

Constant Value:

A positive fixnum, the exact magnitude of which is implementation-dependent, but which is not less than 1024.

Description:

The upper exclusive bound on the array total size of an array.

The actual limit on the array total size imposed by the implementation might vary according the element type of the array; in this case, the value of array-total-size-limit will be the smallest of these possible limits.

See Also:

make-array, array-element-type

Expanded Reference: array-total-size-limit​

Basic Usage​

array-total-size-limit is a constant that specifies the upper exclusive bound on the total number of elements in an array. The actual value is implementation-dependent but must be at least 1024.

;; Check the value (implementation-dependent)
array-total-size-limit
;; => 17592186044416

;; It is always a positive integer
(typep array-total-size-limit '(integer 1024))
=> T

Relationship to Array Creation​

The total size of any array (the product of all its dimensions) must be less than array-total-size-limit.

;; Verify that arrays respect this limit
(< (array-total-size (make-array 1000)) array-total-size-limit)
=> T

(< (array-total-size (make-array '(10 10 10))) array-total-size-limit)
=> T

Checking Before Creating Large Arrays​

(defun can-create-array-p (dimensions)
  "Check if an array with the given dimensions can be created."
  (< (reduce #'* dimensions) array-total-size-limit))

(can-create-array-p '(100 100 100))
=> T

(can-create-array-p '(1000 1000))
=> T