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Yes. It is broken on Windows. (If you print out the handles immediately after the open you'll find that $err is never set.)
What to do about it? You could raise an bug report; but it's been broken for a decade or so already at least; it is unlikely to change anytime soon.
With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
In reply to Re: Is there a problem with IPC::Open on Windows 7?