From: Park Heesob <phasis@...>
Date: 2002-07-14T14:21:22+09:00
Subject: Re: IO.pipe trick ?

Hi,

"Gilles Filippini" <gilles.filippini@free.fr> wrote in message
news:3D30AAF9.96186571@free.fr...
> Hi all,
>
> I need someone shed some light on the following problem.
>
> Here is the culprit script:
> #--------------------------
> output = IO.pipe
> old_out = $defout.dup
> old_out.sync = true
> $defout = output[1]
> thread = Thread.new {
> old_out.puts("@@@@ 1")
> while not output[0].eof?
> old_out.puts("@@@@ 2")
> select([output[0]])
> old_out.write(output[0].read)
> end
> output[0].close
> }
> puts `cat #{ARGV[0]}`
> output[1].close
> thread.join
> #--------------------------
>
> Try this script with a text file for the first argument:
> - if the file's size is less than - say - 8 ko, the script works fine.
> - if the file's size is more than - say - 10 ko, ruby hangs on the
>   while statement.
> What could be the reason for this behavior ?
>

It's probably beause pipe's buffer size is 8192 bytes

Try this:
===============================
output = IO.pipe
old_out = $defout.dup
old_out.sync = true
$defout = output[1]
output[1].sync = true
thread = Thread.new {
old_out.puts("@@@@ 1")
while not output[0].eof?
old_out.puts("@@@@ 2")
select([output[0]])
old_out.write(output[0].read)
end
output[0].close
}
`cat #{ARGV[0]}`.each_byte {|x| print x.chr}
output[1].close
thread.join
==================================

> Thanks in advance.
> _gilles.
>

Park Heesob