From: ahoward <ahoward@...>
Date: 2003-05-07T08:13:17+09:00
Subject: Re: capture output

On Wed, 7 May 2003, Simon Strandgaard wrote:


$stdout and friends are PROCESS based, Kernel.system starts a new process with
it's OWN $stdout and friends - they are not inherited.  you could do something
like this:

~/eg/ruby > cat main.rb
require 'stringio'

def capture
    raise unless block_given?
    a, b, c = $defout, $stderr, $stdout
    buf = StringIO.new(s = "", "w")
    begin
        #$defout, $stderr, $stdout = buf
        $defout, $stderr, $stdout = buf, buf, buf
        yield
    ensure
                buf.close
        $defout, $stderr, $stdout = a, b, c
    end
        s.split(/\n/)
end

res = capture {
        puts "1"
        #system("ruby output.rb")  # BOOM - Output is not being captured?
        load 'output.rb'
        puts "2"
}
puts res.collect{|s| "OK "+s }.join("\n")


~/eg/ruby > cat output.rb
$stderr.puts "stderr"
$stdout.puts "stdout"
$defout.puts "defout"


~/eg/ruby > ruby main.rb
OK 1
OK stderr
OK stdout
OK defout
OK 2


-a

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