#!/usr/bin/newlisp
#
# prodcons.lsp -  Producer/consumer
#
# usage of 'fork', 'semaphore' and 'share'

(load "winfork.lsp")

(constant 'wait -1 'sig 1 'release 0)

(define (consumer n)
	(set 'i 0)
	(while (< i n)
		(semaphore cons-sem wait)
		(println (set 'i (share data)) " <-")
		(semaphore prod-sem sig))  
	(exit))
		
(define (producer n)
	(for (i 1 n)
		(semaphore prod-sem wait)
		(println "-> " (share data i))
		(semaphore cons-sem sig))   
	(exit))

(define (run n)
	(set 'data (share))	
	(share data 0)

	(set 'prod-sem (semaphore)) ; get semaphores
	(set 'cons-sem (semaphore))

	(set 'prod-pid (winfork '(producer n))) ; start threads
	(set 'cons-pid (winfork '(consumer n)))

	(semaphore prod-sem sig) ; get producer started

	(sleep 1000) ; make sure semaphores are not released too early
	
	(semaphore cons-sem release) ; release semaphores
	(semaphore prod-sem release))


(run 10)

(exit)