Threads demo from pickaxe book - newbie question


Please forgive a newbie question - I have tried searching for errata on
the Pickaxe book (2nd ed) but not found an answer. I am running Ruby
1.8.2 on WinXP. I type in, or source from file, the example - from pg.
143, copied below - into the interactive ruby prompt in the fxri tool.
I get to the line

t1.join ; t2.join

and the tool hangs. Is this expected? Is there some better way(s) to
debug thread-related issues? Thanks for any advice -


P.S. Could someone please explain the purpose of the ‘super’ command in
this script? Thx -

-----------------------<begin example pg. 143>----------------------

with my current version of fxri, this hangs

require ‘monitor’
class Counter < Monitor
attr_reader :count
def initialize
@count = 0
def tick
synchronize do
@count += 1

c =
t1 = { 100_000.times { c.tick } }
t2 = { 100_000.times { c.tick } }

t1.join ; t2.join


The super call is calling the initialize function in The base class,
in this case Monitor

I ran your script as a file and not from irb. works just fine, but
really doesn’t show the threads working that well. You should just
try something like

t1 = { 1_000.times { puts ‘thread 1’ } }
t2 = { 1_000.times { puts ‘thread 2’ } }
t3 = { 1_000.times { puts ‘thread 3’ } }
t4= { 1_000.times { puts ‘thread 4’ } }

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs