Module Open4
In: lib/open4.rb
Open4 dot/f_8.png

stolen directly from Open3::open3.rb!

open4.rb: Spawn a program like popen, but with stderr, and pid, too. You might also want to use this if you want to bypass the shell. (By passing multiple args, which IO#popen does not allow)

Usage: 

      require "open4"

     stdin, stdout, stderr, pid = Open4.popen4('nroff -man')
 or
      include Open4
     stdin, stdout, stderr, pid = popen4('nroff -man')

Methods

open4   popen4  

Public Instance methods

open4(*cmd)

Alias for popen4

popen4(*cmd) {|| ...}

[Source]

    # File lib/open4.rb, line 18
18:   def popen4(*cmd)
19: #--{{{
20:     pw = IO::pipe   # pipe[0] for read, pipe[1] for write
21:     pr = IO::pipe
22:     pe = IO::pipe
23: 
24:     verbose = $VERBOSE
25:     begin
26:       $VERBOSE = nil # shut up warning about forking in threads, world writable
27:                      # dirs, etc
28:       cid =
29:         fork{
30:           # child
31:           pw[1].close
32:           STDIN.reopen(pw[0])
33:           pw[0].close
34: 
35:           pr[0].close
36:           STDOUT.reopen(pr[1])
37:           pr[1].close
38: 
39:           pe[0].close
40:           STDERR.reopen(pe[1])
41:           pe[1].close
42: 
43:           STDOUT.sync = true
44:           STDERR.sync = true
45: 
46:           exec(*cmd)
47:         }
48:     ensure
49:       $VERBOSE = verbose
50:     end
51: 
52:     pw[0].close
53:     pr[1].close
54:     pe[1].close
55:     pi = [pw[1], pr[0], pe[0]]
56:     pw[1].sync = true
57:     if defined? yield
58:       begin
59:         yield(cid, *pi)
60:         return(Process::waitpid2(cid).last)
61:       ensure
62:         pi.each{|p| p.close unless p.closed?}
63:       end
64:     end
65:     [cid, pw[1], pr[0], pe[0]]
66: #--}}}
67:   end

[Validate]