# File lib/open3_detach.rb, line 4
 4:   def popen3(*cmd)
 5:     pw = IO::pipe   # pipe[0] for read, pipe[1] for write
 6:     pr = IO::pipe
 7:     pe = IO::pipe
 8: 
 9:     pid = fork{
10:       # child
11:       fork{
12:         # grandchild
13:         pw[1].close
14:         STDIN.reopen(pw[0])
15:         pw[0].close
16: 
17:         pr[0].close
18:         STDOUT.reopen(pr[1])
19:         pr[1].close
20: 
21:         pe[0].close
22:         STDERR.reopen(pe[1])
23:         pe[1].close
24: 
25:         exec(*cmd)
26:       }
27:       exit!(0)
28:     }
29: 
30:     pw[0].close
31:     pr[1].close
32:     pe[1].close
33:     Process.waitpid(pid)
34:     pi = [pw[1], pr[0], pe[0]]
35:     pw[1].sync = true
36:     if defined? yield
37:       begin
38:         return yield(*pi)
39:       ensure
40:         Process.detach(pid) if pid
41:         pi.each { |p| p.close unless p.closed? }
42:       end
43:     end
44:     pi
45:   end