(asdf:oos 'asdf:load-op 'cffi)

(defpackage :cffi-user
  (:use :common-lisp :cffi))

(in-package :cffi-user)

(define-foreign-library libc
  (:unix (:or "libc.so.6" "libc.so.5" "libc.so"))
  (t (:default "libc.so")))

(use-foreign-library libc)

(defcfun "getloadavg" :int (loadavg :pointer) (nelem :int))


(defun load-averages ()
  (let ((loadavg (foreign-alloc :double :count 3)))
    (getloadavg loadavg 3)
    (prog1
      (format nil "~{~,2F~^ ~}" (loop for i from 0 to 2
                                    collect (mem-aref loadavg :double i)))
      (foreign-free loadavg))))

; basic test:
(format t (load-averages))

(defun load-averages ()
  (with-foreign-object (loadavg :double 3)
    (getloadavg loadavg 3)
    (values-list (loop for i from 0 to 2
                    collect (mem-aref loadavg :double i)))))