From: Marko Schulz <in6x059@...>
Date: 2001-04-24T21:06:31+09:00
Subject: [ruby-talk:14149] Re: threads and IO.popen questions

On Tue, Apr 24, 2001 at 04:09:55PM +0900, Jean-Marc Beroud wrote:
> Clemens Wyss <wys@helbling.ch> wrote:
> > the lobal variable $? contains the "exit code" of the last call:
> > I.e.:
> > output = IO.popen( "gzip -cd #{file}" )
> > if not($? == 0) then
> >  print ("Error #{output.read()}")      
> > end
> 
> Doesn't work for me. The value of $? is not set on both cases.
> This seems to be a bug. Example:
> 
> $ rm test.gz
> $ ruby -e'f = IO.popen( "gzip -cd test.gz" ); puts "code = <#{$?}>"'
> test.gz: No such file or directory
> code = <>
> 
> $ echo "hello" | gzip - > test.gz
> $ ruby -e'f = IO.popen( "gzip -cd test.gz" ); puts "code = <#{$?}>"'
> code = <>

I'm not sure about ruby (still new to it and didn't look at the
source), but as far as I can remember Perl sets $? for pipes after
closing it, since you cannot really tell what happened before. It
seems to be the same with ruby:

$ rm test.gz
$ ruby -e'f = IO.popen( "gzip -cd test.gz" ); f.close; puts "code = <#{$?}>"'
test.gz: No such file or directory
code = <256>

$ echo "hello" | gzip - > test.gz
$ ruby -e'f = IO.popen( "gzip -cd test.gz" ); puts "code = <#{$?}>"'
code = <>


-- 
marko schulz

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