Select([]) method

Ruby
1

Hey all
I cam across a new method:
select([], [], [], [])
where the objects in the select parentheses are arrays.

But what does this exactly do? I could not find ANY documentation on
it. The original code is:

ready = select([@irc, $stdin], nil, nil, nil)

Any help please?
ari
-------------------------------------------------------|
~ Ari
crap my sig won’t fit

2

On May 30, 2007, at 7:34 PM, Ari B. wrote:

I cam across a new method:
select([], [], [], [])
where the objects in the select parentheses are arrays.

But what does this exactly do? I could not find ANY documentation
on it. The original code is:

$ ri select
More than one method matched your request. You can refine
your search by asking for information on one of:

  Array#select, Enumerable#select, Hash#select, IO::select,
  IRB::InputCompletor::select_message, Kernel#select,
  MatchData#select, Net::IMAP#select, Struct#select,
  URI::Generic#select, YAML::BaseNode#select!,

YAML::BaseNode#select,
YAML::DBM#select

I think you’re talking about IO::select:

$ ri IO::select
------------------------------------------------------------- IO::select
IO.select(read_array
[, write_array
[, error_array
[, timeout]]] ) => array or nil

It looks like you’re using Mac OS X, so try doing “man select” from
the Terminal for information on the underlying select() function in
the OS.

-Mark

3

On Thu, May 31, 2007 at 11:34:57AM +0900, Ari B. wrote:

Any help please?
Kernel#select is very poorly documented in ri. Try this instead:

http://www.rubycentral.com/book/ref_m_kernel.html#Kernel.select

4

On Thursday 31 May 2007 02:34, Ari B. wrote:

Any help please?
ari
-------------------------------------------------------|
~ Ari
crap my sig won’t fit

it’s just wraper for c / linux select
you can try man select if you have libc documentation

5

On 5/31/07, Ari B. [email protected] wrote:

Hey all
I cam across a new method:
select([], [], [], [])
where the objects in the select parentheses are arrays.

But what does this exactly do? I could not find ANY documentation on
it. The original code is:

ready = select([@irc, $stdin], nil, nil, nil)

I agree with other comments, the documentation for select is pretty bad.

The most simple way to use it is like this:

svrs = IO.select([my_fd], nil, nil, 0)
svrs[0].each { |io| puts io.readline }

6

On May 31, 2007, at 10:12 AM, Felipe C. wrote:

I agree with other comments, the documentation for select is pretty
bad.

The most simple way to use it is like this:

svrs = IO.select([my_fd], nil, nil, 0)
svrs[0].each { |io| puts io.readline }

Alright, thanks everyone! This really cleared it up, and now i
learned like 800 new things about ruby. BTW, the link that was tossed
was definitely a great link. Thanks!

ari
--------------------------------------------|
If you’re not living on the edge,
then you’re just wasting space.

7

In a nutshell, select() is a system call for use when you have
multiple IO events pending, and you want to handle the first one that
occurs. So for instance if you have three network connections, and
you need wait until data comes in on one of them, you could use
select().