C-like ugliness of Kernel#select

ruby-talk
1

IO has such methods as #closed? and #eof? to find much-needed information
about IO status, but it doesn't have anything like #read_ready? or
#write_ready? that would be useful for anyone not wanting blocking IO. The
only way to do this is with the C-like ugly-hackishness that is
Kernel#select.

Does anyone have a good argument for not adding a few more methods to IO in
the Ruby distribution itself ? Does anybody think it would be a good idea to
submit this as an RCR ? If those are added, would we be able to remove
Kernel#select in the next "we don't care about backward compatibility" Ruby
version ?

2

IO has such methods as #closed? and #eof? to find much-needed information
about IO status, but it doesn't have anything like #read_ready? or
#write_ready? that would be useful for anyone not wanting blocking IO. The
only way to do this is with the C-like ugly-hackishness that is
Kernel#select.

Does anyone have a good argument for not adding a few more methods to IO
in the Ruby distribution itself ?

Not me.

Does anybody think it would be a good idea to submit this as an RCR ?

Go ahead. After submitting it, announce the RCR in ruby-core as well
and let the vote decide. Myself, I'm for adding a few convenience
methods as a wrapper to specific select calls.

If those are added, would we be able to remove Kernel#select in the next
"we don't care about backward compatibility" Ruby version ?

I wouldn't go that far. As I said above, I would probably implement
the convenience methods as wrappers to select, unless performance
issues were to require a lower level implementation. And leaving
access to the unwrapped select would be nearly essential to many
useful libraries.

Jacob Fugal

···

On 6/28/05, C Erler <erlercw@gmail.com> wrote:

3

IO has such methods as #closed? and #eof? to find much-needed information
about IO status, but it doesn't have anything like #read_ready? or
#write_ready? that would be useful for anyone not wanting blocking IO. The
only way to do this is with the C-like ugly-hackishness that is
Kernel#select.

Look in RAA for io-wait.

Does anyone have a good argument for not adding a few more methods to IO in
the Ruby distribution itself ? Does anybody think it would be a good idea to
submit this as an RCR ?

It could be useful.

If those are added, would we be able to remove
Kernel#select in the next "we don't care about backward compatibility" Ruby
version ?

No. Kernel#select would still be useful to wait on many IO streams at
once.

Guillaume.

···

On Wed, 2005-06-29 at 03:16 +0900, C Erler wrote:

4

harp:~ > cat a.rb
   require 'io/wait'
   STDOUT.sync = true
   pipe = IO::popen 'while true;do sleep 2; echo 42; done'
   threads =
   threads << Thread::new{ loop{ puts "not blocked @ <#{ Time::now }>"; sleep 0.42 } }
   threads << Thread::new{ loop{ (pipe.ready? and puts("buf <#{ pipe.gets.chomp }>")) or sleep 0.42 } }
   threads.each{|t| t.join}

   harp:~ > ruby a.rb
   not blocked @ <Tue Jun 28 14:52:45 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:46 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:47 MDT 2005>
   buf <42>
   not blocked @ <Tue Jun 28 14:52:47 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:48 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:49 MDT 2005>
   buf <42>
   not blocked @ <Tue Jun 28 14:52:49 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:50 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:51 MDT 2005>
   buf <42>
   not blocked @ <Tue Jun 28 14:52:51 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:52 MDT 2005>
   not blocked @ <Tue Jun 28 14:52:53 MDT 2005>
   buf <42>
   not blocked @ <Tue Jun 28 14:52:53 MDT 2005>
   ...

know yer standard libs :wink: i don't think this work on windows - but it is in
the standard dist.

hth.

-a

···

On Wed, 29 Jun 2005, C Erler wrote:

IO has such methods as #closed? and #eof? to find much-needed information
about IO status, but it doesn't have anything like #read_ready? or
#write_ready? that would be useful for anyone not wanting blocking IO. The
only way to do this is with the C-like ugly-hackishness that is
Kernel#select.

Does anyone have a good argument for not adding a few more methods to IO in
the Ruby distribution itself ? Does anybody think it would be a good idea to
submit this as an RCR ? If those are added, would we be able to remove
Kernel#select in the next "we don't care about backward compatibility" Ruby
version ?

--

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phone :: 303.497.6469
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