[#376274] Best Linux Distro for Ruby? — Nick Hird <boondox@...>

What are some of the better linux distro's for ruby development? I know

15 messages 2011/01/02

[#376329] Is singleton class of an object already created? — Samnang Chhun <samnang.chhun@...>

I would like to know is there any ways to check is singleton class of an

12 messages 2011/01/04

[#376333] Threading in ruby — "Vishnu I." <pathsny@...>

Hi

13 messages 2011/01/04
[#376335] Re: Threading in ruby — Robert Klemme <shortcutter@...> 2011/01/04

On Tue, Jan 4, 2011 at 8:41 AM, Vishnu I. <pathsny@gmail.com> wrote:

[#376339] ripl - an irb alternative - 0.3.0 released — ghorner <gabriel.horner@...>

ripl, a light modular alternative to irb, has reached 0.3.0. ripl

32 messages 2011/01/04

[#376382] Class Initialization? — Kedar Mhaswade <kedar.mhaswade@...>

I have a class and two class methods: self.encode and self.decode. The

14 messages 2011/01/05
[#376385] Re: Class Initialization? — Andrew Wagner <wagner.andrew@...> 2011/01/05

On Wed, Jan 5, 2011 at 9:33 AM, Kedar Mhaswade <kedar.mhaswade@gmail.com>wrote:

[#376388] Petition to add Metasploit Project as Ruby success story — Christian Kirsch <Christian_Kirsch@...7.com>

I noticed the Ruby success stories on the Ruby website. I would like to mak=

10 messages 2011/01/05

[#376453] Block variable - How is it read in English? — SW Engineer <abder.rahman.ali@...>

Following the "Ruby on Rails Tutorial", and under section "6.1.1

16 messages 2011/01/06

[#376574] Best way for Array#find+transform ? — "Jonas Pfenniger (zimbatm)" <jonas@...>

There is a pattern that I'm using quite regularly, but I'm not

17 messages 2011/01/08
[#376575] Re: Best way for Array#find+transform ? — Anurag Priyam <anurag08priyam@...> 2011/01/08

> I know I can come up with a new method on Array that would shorten this t=

[#376576] Re: Best way for Array#find+transform ? — Anurag Priyam <anurag08priyam@...> 2011/01/08

> paths.map{|path| File.join(path, filename)}.select{|name| File.exist?(path)}

[#376577] Re: Best way for Array#find+transform ? — "Jonas Pfenniger (zimbatm)" <jonas@...> 2011/01/09

2011/1/8 Anurag Priyam <anurag08priyam@gmail.com>:

[#376579] Re: Best way for Array#find+transform ? — David J. Hamilton <groups@...> 2011/01/09

Excerpts from Jonas Pfenniger (zimbatm)'s message of Sat Jan 08 16:05:05 -0800 2011:

[#376586] Re: Best way for Array#find+transform ? — "Jonas Pfenniger (zimbatm)" <jonas@...> 2011/01/09

2011/1/9 David J. Hamilton <groups@hjdivad.com>:

[#376606] Re: Best way for Array#find+transform ? — David J. Hamilton <groups@...> 2011/01/10

Excerpts from Jonas Pfenniger (zimbatm)'s message of Sun Jan 09 04:08:10 -0800 2011:

[#376680] Parallel Assignments and Elegance/Complexity Ratio. — Kedar Mhaswade <kedar.mhaswade@...>

In SICP, I read that "Programs should be written for people to read, and

15 messages 2011/01/11
[#376697] Re: Parallel Assignments and Elegance/Complexity Ratio. — Josh Cheek <josh.cheek@...> 2011/01/11

On Tue, Jan 11, 2011 at 8:29 AM, Kedar Mhaswade <kedar.mhaswade@gmail.com>wrote:

[#376682] JRuby 1.6.0.RC1 released — Thomas E Enebo <tom.enebo@...>

The JRuby community is pleased to announce the release of JRuby 1.6.0.RC1.

14 messages 2011/01/11

[#376744] Case statements - Just beautification — flebber <flebber.crue@...>

I just want to clarify case statements the name after the word case is

10 messages 2011/01/12

[#376792] Ruby is interpreted and scripting language? — Sai Babu <sateesh.mca09@...>

I am ruby fresher.

16 messages 2011/01/13

[#376855] Retrieving and copying element from array — Simon Harrison <simon@...>

If I have an array like this:

11 messages 2011/01/13

[#376898] What are your ruby rough cuts ? — "Jonas Pfenniger (zimbatm)" <jonas@...>

Hi rubyists,

32 messages 2011/01/14
[#376930] Re: [poll] What are your ruby rough cuts ? — David Masover <ninja@...> 2011/01/15

On Friday, January 14, 2011 07:34:04 am Jonas Pfenniger (zimbatm) wrote:

[#376937] Re: What are your ruby rough cuts ? — Joseph Lenton <jl235@...> 2011/01/15

David Masover wrote in post #975080:

[#376959] Why Quby? (was Re: What are your ruby rough cuts ?) — David Masover <ninja@...> 2011/01/15

On Saturday, January 15, 2011 04:42:58 am Joseph Lenton wrote:

[#377020] Obscure syntax error — Rolf Timmermans <molfie@...>

Hi all,

16 messages 2011/01/17

[#377052] Calling by Reference - Two Questions — Mike Stephens <rubfor@...>

I know I'm not the first person to get stumped by how to get Ruby to

15 messages 2011/01/18

[#377072] The most recommended way of naming methods in Ruby — Edmond Kachale <edmond.kachale@...>

Rubists,

14 messages 2011/01/18
[#377082] Re: The most recommended way of naming methods in Ruby — Phillip Gawlowski <cmdjackryan@...> 2011/01/18

On Tue, Jan 18, 2011 at 9:16 AM, Edmond Kachale

[#377121] Improving performance of hash math — dblock <dblockdotorg@...>

I am trying to improve performance of Euclidian distance between two

13 messages 2011/01/19

[#377226] Totally lost in learning Ruby — Hilary Bailey <my77elephants@...>

This is my second attempt to understand Ruby. I completely read 1)

61 messages 2011/01/21
[#378239] Re: Totally lost in learning Ruby — Hilary Bailey <my77elephants@...> 2011/02/08

Hi everybody,

[#378246] Re: Totally lost in learning Ruby — Robert Klemme <shortcutter@...> 2011/02/08

On Tue, Feb 8, 2011 at 3:16 AM, Hilary Bailey <my77elephants@gmail.com> wro=

[#377236] using gems installed via 'sudo gem install' — "Piotr S." <thisredoned@...>

I've installed ruby-opengl through sudo gem install because there were

15 messages 2011/01/21

[#377362] pg gem 0.10.1 wth Ruby 1.9.2 does not work with method @pg_conn.exec_prepared(stmt_name, parameters) — Zeno Davatz <zdavatz@...>

Hi

9 messages 2011/01/24

[#377388] The finer points of postfix conditionals. — Jon Leighton <j@...>

Hi,

13 messages 2011/01/24

[#377411] Obtain data from .csv — Kamarulnizam Rahim <niezam54@...>

Sample of .csv file:

19 messages 2011/01/25

[#377609] why is overloading invalid in ruby. — Ted Flethuseo <flethuseo@...>

I don't understand why when I try to overload I get an error. Can I

36 messages 2011/01/27

[#377645] If you had the choice between Ruby & Groovy — Noah Cutler <sit1way@...>

Hey All.

15 messages 2011/01/28

[#377650] IDE? — <johan.tempelman@...>

Hi,

13 messages 2011/01/28

[#377703] Zlib::GzipReader and multiple compressed blobs in a single stream — Jos Backus <jos@...>

Hi,

11 messages 2011/01/28

[#377761] New to programming AND new to Ruby — "Cassandra K." <cassandra.k@...>

Hello. I am trying to teach myself Ruby. I have no background in

13 messages 2011/01/31

[#377785] 2011: Which Ruby books have you read? And which would you recommend? — "Aston J." <azzzz@...>

I know there are a lot of threads about books, but some of them are as

16 messages 2011/01/31

[#377800] How to know the exit status within at_exit() block? — Iñaki Baz Castillo <ibc@...>

Hi, my program invokes "exit true" or "exit false" and I want to catch

17 messages 2011/01/31

Re: Thread Variable race condition

From: Robert Klemme <shortcutter@...>
Date: 2011-01-13 14:24:09 UTC
List: ruby-talk #376835
On Thu, Jan 13, 2011 at 11:59 AM, Karan Rajput <ganeshgirase@gmail.com> wro=
te:
> Hi,
>
>
> I am not enough efficient in Threads.
> Here is the problem.
>
>
> i =3D 1
> while(i < 100)
>
> =A0 t =3D Thread.new do
> =A0 =A0 =A0echo(i)
> =A0 end
> =A0 t.join if (i % 5 =3D=3D 0)
> =A0 i =3D i + 1
> end
>
> def echo(num)
> puts num
> end
>
> I get output sometimes as,
>
> 1
> 2
> 3
> 5
> 5 =3D=3D> 5 is getting duplicated whereas 4 is dropped. I feel its race
> condition for variable.

No, this is not an indicator of a race condition.  Even with proper
synchronization it may happen that two threads that you started get
scheduled before the next increment occurs and they thus print the
same value.

> 6.... and so on.
>
> This error occurred for any random number.

It's not an error - although your code is of course not thread safe
because you do not synchronize.

> Sometime i get the correct output.

What you consider a "correct output" (I assume a sequence where each
printed value is one higher than the previous value) is no more
correct than what you see.  You may even see output where the order is
reversed (e.g. 1 2 4 3 5) because any thread might be interrupted at
any point between fetching the value and printing it.  Granted, it's
not too likely but perfectly valid and must be expected.

> Can anybody suggest what will be solution to avoid any such problem.
> Will replacement of Thread with Process will solve problem?

Certainly not.  With processes you don't have shared memory any more.
You would put in more effort and make processes communicate with each
other (e.g. via DRb) - typically one process will hold the counter and
others would do the printing.  But even then you need proper
synchronization.

> I am hoping solution in Threads only if its possible.

The question is: for which problem do you need a solution?  If you
just want to print a sequence of values you don't need threads.  You
can just do

100.times {|i| puts i}

Kind regards

robert

--=20
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

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