ruby at_exit 退出状态

Question

Can i determine selves process exit status in at_exit block?

at_exit do
  if this_process_status.success?
    print 'Success'
  else
    print 'Failure'
  end
end

Answer 1

using idea from tadman

at_exit do
  if $!.nil? || ($!.is_a?(SystemExit) && $!.success?)
    print 'success'
  else
    code = $!.is_a?(SystemExit) ? $!.status : 1
    print "failure with code #{code}"
  end
end

or without Perlisms:

require 'English'

at_exit do
  if $ERROR_INFO.nil? || ($ERROR_INFO.is_a?(SystemExit) && $ERROR_INFO.success?)
    print 'success'
  else
    code = $ERROR_INFO.is_a?(SystemExit) ? $ERROR_INFO.status : 1
    print "failure with code #{code}"
  end
end

Answer 2

Although the documentation on this is really thin, $! is set to be the last exception that occurs, and after an exit() call this is a SystemExit exception. Putting those two together you get this:

at_exit do
  if ($!.success?)
    print 'Success'
  else
    print 'Failure'
  end
end