src/condition-variables.lisp

   1 ;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; indent-tabs-mode: nil -*-
   2
   3 #|
   4 Copyright 2006, 2007 Greg Pfeil
   5
   6 Distributed under the MIT license (see LICENSE file)
   7 |#
   8
   9 (in-package #:bordeaux-threads)
  10
  11 ;;; This file provides a portable implementation of condition
  12 ;;; variables (given a working WITH-LOCK-HELD and THREAD-YIELD), and
  13 ;;; should be used if there is no condition variable implementation in
  14 ;;; the host Lisp.
  15
  16 (defstruct condition-var
  17   lock
  18   active)
  19
  20 (defun condition-wait (condition-variable lock)
  21   (check-type condition-variable condition-var)
  22   (setf (condition-var-active condition-variable) nil)
  23   (release-lock lock)
  24   (do ()
  25       ((when (condition-var-active condition-variable)
  26          (acquire-lock lock)
  27          t))
  28     (thread-yield)))
  29
  30 (defun condition-notify (condition-variable)
  31   (check-type condition-variable condition-var)
  32   (with-lock-held ((condition-var-lock condition-variable))
  33     (setf (condition-var-active condition-variable) t)))