newlisp/examples/prodcons.lsp

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#!/usr/bin/env newlisp
# prodcons.lsp - Producer/consumer
#
# this program only runs on Linux/UNIX
#
# usage of 'fork', 'wait-pid', 'semaphore' and 'share'
(when (= ostype "Windows")
(println "this will not run on Windows")
(exit))
(constant 'wait -1 'sig 1 'release 0)
(define (consumer n)
(set 'i 0)
(while (< i n)
(semaphore cons-sem wait)
(print (set 'i (share data)) "\r")
(semaphore prod-sem sig))
(exit))
(define (producer n)
(for (i 1 n)
(semaphore prod-sem wait)
(print "-> " (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 (fork (producer n))) ; start threads
(set 'cons-pid (fork (consumer n)))
(semaphore prod-sem sig) ; get producer started
(wait-pid prod-pid) ; wait for threads to finish
(wait-pid cons-pid) ;
(semaphore cons-sem release) ; release semaphores
(semaphore prod-sem release))
(set 'N (or (int (main-args -1)) 100000))
(set 'duration (time (run N)))
(println (div duration N) " ms per exchange")
(exit)