From: Yusuke ENDOH <mame@...>
Date: 2010-11-15T12:29:14+09:00
Subject: [ruby-core:33186] Re: [Ruby 1.9-Feature#4046][Open] Saving C's **argv and cwd allows Ruby programs to reliably restart themselves

Hi,

2010/11/12 Rocky Bernstein <redmine@ruby-lang.org>:
> In a debugger often one gets to a state where one just wants to restart everything exactly the way the program was previously invoked.


exec(3) allows us to fake argv[0].
Unfortunately, there is no truely reliable way to re-invoke process,
at least, in Unix.


  $ cat test.rb
  #
  # test.rb
  #
  Dir.chdir RubyVM::OS_STARTUP_DIR
  puts "***"
  puts "*** exec: %p" % RubyVM::OS_ARGV.join(" ")
  puts "***"
  exec(*RubyVM::OS_ARGV)



  # http://cr.yp.to/ucspi-tcp/argv0.html
  $ argv0 ./ruby cat test.rb
  ***
  *** exec: "cat test.rb"
  ***
  #
  # test.rb
  #
  Dir.chdir RubyVM::OS_STARTUP_DIR
  puts "***"
  puts "*** exec: %p" % RubyVM::OS_ARGV.join(" ")
  puts "***"
  exec(*RubyVM::OS_ARGV)



  # You can do the same with perl, ruby, etc.
  $ perl -e 'exec { "./ruby" } ("cat", "test.rb")'
  $ ruby -e 'exec(["./ruby", "cat"], "test.rb")'

-- 
Yusuke Endoh <mame@tsg.ne.jp>