From: Robert Klemme <bob.news@...>
Date: 2004-03-26T23:19:28+09:00
Subject: Save to use const Regexp in several threads?


Hi all,

out of curiosity: is it safe to define a global constant regular
expression and use that concurrently from several threads?  I put together
a test script that seems to indicate it is safe, but a test is no definite
answer.

Kind regards

    robert

#!/usr/bin/ruby

require 'set'

RX = /./

threads = []

def create(s)
  Thread.new(s) do |str|
    set = Set.new

    str.scan(RX) do |m|
      set << m
      Thread.pass
    end

    # set should contain more than one entry if
    # it is not safe
    p set.to_a
  end
end

%w{a b c d e f}.each do |c|
  threads << create(c * 1000)
end

threads.each {|th| th.join}