open3 only takes STDIN, STDOUT and STDERR. If the command being run uses other file descriptors then open3 cannot capture those:

    echo foo # Can be captured
    echo foo >&2 # Can be captured
    echo foo >&3 # Cannot be captured (with open3)
[download]

I have looked into IPC::Run::run which seems to be able to deal with that, but I also need the PID and I found no way for IPC::Run::run to give me that. Also IPC::Run is not installed on many of the old distributions supported by GNU Parallel, whereas open3 is.

How can I wrap open3 so that I can capture file descriptors 3..61 in the same way I can capture STDOUT and STDERR?

Background

This is intended for a possible extension of GNU Parallel, so you can do:

    # Currently mixes output due to fd 3 not buffered
    parallel 'echo {} start >&3;sleep 10;echo {} end >&3' ::: a b c 3>
+out.file
[download]

without having the output from different jobs mixed. Right now only STDOUT and STDERR are buffered and thus guaranteed not to mix.

    # This currently works
    parallel 'echo {} start >&2;sleep 10;echo {} end >&2' ::: a b c 2>
+out.file
[download]

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.