(define fc 5)
(define sc 5)

(define first_tid (thread-create (while (> fc 0) (do (thread-under-lock "ilock" (do (set! fc (dec fc))(print 1))) (thread-sleep 500)))))
(define second_tid (thread-create (while (> sc 0) (do (thread-under-lock "ilock" (do (set! sc (dec sc))(print 2))) (thread-sleep 750)))))

(print "first thread id:" first_tid)
(print "second thread id:" second_tid)
(threads-join)
(print "ok")

(try 
    (ls-dir "nonexisting/dir")
    (print "dir not exists"))

(try 
    (throw "my-exception")
    (print "exception caught:" ml-exception))

(/ 1 0)