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machine-type

machine-type Function

Syntax:

machine-type ⟨no arguments⟩ → description

Arguments and Values:

description—a string or nil.

Description:

Returns a string that identifies the generic name of the computer hardware on which Common Lisp is running.

Examples:

(machine-type) 
→ "DEC PDP-10" 
<i><sup>or</sup>→</i> "Symbolics LM-2"

Affected By:

The machine type. The implementation.

See Also:

machine-version

Expanded Reference: machine-type​

Basic Usage​

machine-type returns a string identifying the hardware type (CPU architecture) of the machine running the Lisp implementation. The exact value is implementation-dependent.

(machine-type)
=> "X86-64"

Typical Return Values​

The returned string varies by implementation and platform. Common values include architecture names.

;; On a 64-bit x86 system (SBCL): "X86-64"
;; On an ARM system (Apple Silicon): "ARM64"
;; If unknown: NIL
(or (stringp (machine-type)) (null (machine-type)))
;; => T

Conditional Behavior Based on Architecture​

You can use machine-type to adjust behavior based on the hardware platform, though relying on specific strings is inherently non-portable.

(defun pointer-size-heuristic ()
  (let ((mt (machine-type)))
    (cond
      ((and mt (search "64" mt)) "Likely 64-bit architecture")
      ((and mt (search "86" mt)) "Likely 32-bit x86 architecture")
      (t "Unknown architecture"))))

(pointer-size-heuristic)
=> "Likely 64-bit architecture"

Important Notes​

The return value is a string or NIL. There is no standard format for the returned string, so portable code should not depend on its exact contents.