in reply to Re: IPC::Open3 misbehaving when STDOUT is not FD #1
in thread IPC::Open3 misbehaving when STDOUT is not FD #1

So will
#!/usr/bin/perl print <<'__EOI__'; PIPE: out 1 PIPE: out 2 PIPE: out 3 PIPE: err 1 PIPE: err 2 PIPE: err 3 __EOI__

True, but completely unhelpful.

I posted my comments to the OP in RT.