figuring out MRI and JRuby's use of system()

JRuby 1.6.0RC2 (2011-02-09 5434c72 and 2011-02-25 c813123) results

C:\Users\Jon\Documents\RubyDev\sandbox>jruby --1.9 -Xlaunch.inproc=false system_ruby.rb --start
[INFO] doing some work via system()...
jruby 1.6.0.RC2 (ruby 1.9.2 patchlevel 136) (2011-02-09 5434c72) (Java HotSpot(TM) Client VM 1.6.0_24) [Windows 7-x86-java]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--start' style
*** FAIL: both hang with 1st system after starting .exe, never return ***


C:\Users\Jon\Documents\RubyDev\sandbox>jruby --1.9 -Xlaunch.inproc=false system_ruby.rb --cmd-start
[INFO] doing some work via system()...
jruby 1.6.0.RC2 (ruby 1.9.2 patchlevel 136) (2011-02-09 5434c72) (Java HotSpot(TM) Client VM 1.6.0_24) [Windows 7-x86-java]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--cmd-start' style
*** FAIL: both hang with 1st system after starting .exe, never return ***


C:\Users\Jon\Documents\RubyDev\sandbox>jruby --1.9 -Xlaunch.inproc=false system_ruby.rb --popen
[INFO] doing some work via system()...
jruby 1.6.0.RC2 (ruby 1.9.2 patchlevel 136) (2011-02-09 5434c72) (Java HotSpot(TM) Client VM 1.6.0_24) [Windows 7-x86-java]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--popen' style
[INFO] back from 1st system; starting 2nd system
*** FAIL ***
  5434c72: did not start .exe; required CTRL-C to exit
  c813123: started .exe but never returned from 1st system


C:\Users\Jon\Documents\RubyDev\sandbox>jruby --1.9 -Xlaunch.inproc=false system_ruby.rb --popen-start-str
[INFO] doing some work via system()...
jruby 1.6.0.RC2 (ruby 1.9.2 patchlevel 136) (2011-02-09 5434c72) (Java HotSpot(TM) Client VM 1.6.0_24) [Windows 7-x86-java]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--popen-start-str' style
org/jruby/RubyIO.java:3675:in `popen19': Cannot run program "start" (in directory "C:\
Users\Jon\Documents\RubyDev\sandbox"): CreateProcess error=2, The system cannot find t
he file specified (IOError)
        from system_ruby.rb:32:in `fails'
        from system_ruby.rb:71:in `(root)'
*** FAIL ***


C:\Users\Jon\Documents\RubyDev\sandbox>jruby --1.9 -Xlaunch.inproc=false system_ruby.rb --popen-args
[INFO] doing some work via system()...
jruby 1.6.0.RC2 (ruby 1.9.2 patchlevel 136) (2011-02-09 5434c72) (Java HotSpot(TM) Client VM 1.6.0_24) [Windows 7-x86-java]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--popen-args' style
[INFO] back from 1st system; starting 2nd system
*** FAIL ***
  5434c72: required CTRL-C to exit
  c813123: did not start .exe but completed

MRI 1.9.2-p180 results

C:\Users\Jon\Documents\RubyDev\sandbox>ruby system_ruby.rb --start
[INFO] doing some work via system()...
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--start' style
[INFO] back from 1st system; starting 2nd system
[INFO] back from 2nd system; starting 3rd system
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] back from 3rd system; starting final system
[INFO] back from final system
[INFO] OK, I'm back from the failing case.
*** PASS ***


C:\Users\Jon\Documents\RubyDev\sandbox>ruby system_ruby.rb --cmd-start
[INFO] doing some work via system()...
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--cmd-start' style
[INFO] back from 1st system; starting 2nd system
[INFO] back from 2nd system; starting 3rd system
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] back from 3rd system; starting final system
[INFO] back from final system
[INFO] OK, I'm back from the failing case.
*** PASS ***


C:\Users\Jon\Documents\RubyDev\sandbox>ruby system_ruby.rb --popen
[INFO] doing some work via system()...
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--popen' style
[INFO] back from 1st system; starting 2nd system
[INFO] back from 2nd system; starting 3rd system
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] back from 3rd system; starting final system
[INFO] back from final system
[INFO] OK, I'm back from the failing case.
*** FAIL: hang with 1st system; never returned ***


C:\Users\Jon\Documents\RubyDev\sandbox>ruby system_ruby.rb --popen-start-str
[INFO] doing some work via system()...
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--popen-start-str' style
[INFO] back from 1st system; starting 2nd system
[INFO] back from 2nd system; starting 3rd system
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] back from 3rd system; starting final system
[INFO] back from final system
[INFO] OK, I'm back from the failing case.
*** PASS ***


C:\Users\Jon\Documents\RubyDev\sandbox>ruby system_ruby.rb --popen-args
[INFO] doing some work via system()...
ruby 1.9.2p180 (2011-02-18 revision 30907) [i386-mingw32]
[INFO] OK, I'm back from the working case.
[INFO] playing with processes via system()...
[INFO] starting 1st system using '--popen-args' style
*** FAIL: hang with 1st system; never returned ***

system_ruby.rb

# usage:
#
#   0) i only like windows systems
#   1) download and extract Process Monitor zip from
#        http://technet.microsoft.com/en-us/sysinternals/bb896645
#   2) edit 'exe' to match Process Monitor install
#   3) manually run 'procmon.exe' once to accept EULA
#   4) 'ruby system_ruby.rb' or 'jruby [--1.9] -Xlaunch.inproc=false system_ruby.rb'
#      from an administrator command prompt

require 'rubygems'

$exe = 'c:/winsystools/ProcessMonitor/procmon.exe'
$log_dir = ENV['temp'] || ENV['tmp']
$log_file = File.expand_path(File.join($log_dir, 'api_trace.pml'))
  
def works(options={})
  system("#{Gem.ruby} #{options[:niner]} #{options[:jruby_inproc]} -ve \"\"")
end

def fails(options={})
  puts "[INFO] starting 1st system using '#{options[:style]}' style"
  base_cmd = "/quiet /minimized /backingfile #{$log_file}"
  case options[:style]
  when '--start'
    system("start #{$exe} #{base_cmd}")
  when '--cmd-start'
    system("cmd /c start #{$exe} #{base_cmd}")
  when '--popen'
    IO.popen("#{$exe} #{base_cmd}", 'r+') { |io| }
  when '--popen-start-str'
    IO.popen("start #{$exe} #{base_cmd}", 'r+') { |io| }
  when '--popen-args'
    IO.popen(["#{$exe}", "#{base_cmd}"], 'r+') { |io| }
  end

  puts '[INFO] back from 1st system; starting 2nd system'
  system("#{$exe} /waitforidle")

  puts '[INFO] back from 2nd system; starting 3rd system'
  system("#{Gem.ruby} #{options[:niner]} #{options[:jruby_inproc]} -ve \"\"")

  puts '[INFO] back from 3rd system; starting final system'
  system("#{$exe} /terminate")
  puts '[INFO] back from final system'
end


if __FILE__ == $0

  opts = {}
  opts[:style] = ARGV.delete('--start')        ||
                 ARGV.delete('--cmd-start')    ||
                 ARGV.delete('--popen')        ||
                 ARGV.delete('--popen-args')   ||
                 ARGV.delete('--popen-start-str')
  unless opts[:style]
    abort '[ERROR] must provide --start, --cmd-start, --popen, --popen-args, or --popen-start-str'
  end

  if RUBY_PLATFORM =~ /java/i
    opts[:niner] = '--1.9'
    opts[:jruby_inproc] = '-Xlaunch.inproc=false'
  end

  puts '[INFO] doing some work via system()...'
  works(opts)
  puts "[INFO] OK, I'm back from the working case."

  puts '[INFO] playing with processes via system()...'
  fails(opts)
  puts "[INFO] OK, I'm back from the failing case."

end