[Q] Problem with popen on WIn32 (1.8.x)

[Laurent Julliard]

Can anybody tell me why the following Ruby code that uses popen
doesn't work at all on my Windows XP (Pro SP1) machine, ruby 1.8.2
preview2 or 1.8.1?

you.rb
------
while true
sleep 1
puts "This line should print in me.rb"
end

me.rb
-----
pig = IO.popen("ruby.exe you.rb", "w+")

while true
pig.gets
end

Launch me.rb and you'll see that no output is showing at all. On Linux
it works like a charm.

If you succeed in making this work can you tell me which version of
Ruby and Windows you are using?

Thanks for all your help

Laurent

 

[Ara.T.Howard]

Can anybody tell me why the following Ruby code that uses popen
doesn't work at all on my Windows XP (Pro SP1) machine, ruby 1.8.2
preview2 or 1.8.1?

you.rb
------
while true
sleep 1
puts "This line should print in me.rb"
end

me.rb
-----
pig = IO.popen("ruby.exe you.rb", "w+")

while true
pig.gets
end

Launch me.rb and you'll see that no output is showing at all. On Linux
it works like a charm.

If you succeed in making this work can you tell me which version of
Ruby and Windows you are using?

Thanks for all your help

Laurent

perhaps putting STDOUT.sync = true in you.rb might help??

-a
--
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| bonfire, leaving no trace of yourself. --Shunryu Suzuki
===============================================================================

 

[Laurent Julliard]

perhaps putting STDOUT.sync = true in you.rb might help??

I tried that already but it doesn't make a difference. However if you
remove the sleep statement it works!!!??? Any idea ?

Laurent

 

[Robert Klemme]

Can anybody tell me why the following Ruby code that uses popen doesn't
work at all on my Windows XP (Pro SP1) machine, ruby 1.8.2 preview2 or
1.8.1?

you.rb
------
while true
sleep 1
puts "This line should print in me.rb"
end

me.rb
-----
pig = IO.popen("ruby.exe you.rb", "w+")

while true
pig.gets
end

Launch me.rb and you'll see that no output is showing at all. On Linux it
works like a charm.

If you succeed in making this work can you tell me which version of Ruby
and Windows you are using?

Thanks for all your help

)) You forgot the "puts" in me.rb. For me, this works:

you.rb

while true
sleep 1
puts "This line should print in me.rb"
end


me.rb

pig = IO.popen("ruby.exe you.rb", "w+")

while true
puts pig.gets
end

If you're not patient, then you should use synchronized output, i.e. switch
on flushing of every line like this in the first line of me.rb:

$defout.sync=true

Otherwise it'll take some time until the pipe fills and you see first
results on the reader side. But when they come they come in chunks of
several lines.

Btw, I'd use the block form to ensure proper cleanup and used flag "r"
because we want to read only here. (I know that this is useless in this
case, but IMHO it's better to start with the better pattern right from the
start. Can save you some time later when you don't have to hunt down
strange bugs.) So I had written me.rb like this:

me2.rb

IO.popen("ruby.exe you.rb", "r") do |pig|
while ( line = pig.gets )
puts line
end
end

Kind regards

robert

 

[nobu.nokada]

Hi,

At Sat, 23 Oct 2004 06:21:54 +0900,
Laurent Julliard wrote in [ruby-talk:117409]:

Can anybody tell me why the following Ruby code that uses popen
doesn't work at all on my Windows XP (Pro SP1) machine, ruby 1.8.2
preview2 or 1.8.1?

It may be a recently fixed bug.

 

[Laurent Julliard]

)) You forgot the "puts" in me.rb. For me, this works:

you.rb

while true
sleep 1
puts "This line should print in me.rb"
end


me.rb

pig = IO.popen("ruby.exe you.rb", "w+")

while true
puts pig.gets
end

I forgot the puts while copy-pasting the code but even with the puts
it doesn't make any difference. It still doesn't work on 1.8.2 preview
2/XP. Which version on Ruby/Windows are you using?

Laurent

 

[Robert Klemme]

I forgot the puts while copy-pasting the code but even with the puts it
doesn't make any difference.

How long did you wait to see any output? With "sleep 1" it takes
considerable time until the pipe is full and the first chunk of messages
appear - on my machine it's just above 30 seconds.

It still doesn't work on 1.8.2 preview 2/XP. Which version on Ruby/Windows
are you using?

Robert@Babelfish2 ~
$ uname -a
CYGWIN_NT-5.1 Babelfish2 1.5.10(0.116/4/2) 2004-05-25 22:07 i686 unknown
unknown Cygwin

Robert@Babelfish2 ~
$ ruby -v
ruby 1.8.1 (2003-12-25) [i386-cygwin]

Robert@Babelfish2 ~
$ cmd /c ver

Microsoft Windows XP [Version 5.1.2600]

(SP2 installed)

Kind regards

robert