package require rechan
proc RechanProc {base_channel cmd chan args} {
    switch -exact -- $cmd {
        seek { return 0 }
        read { return "" }
        write { return 0 }
        close {
            close $base_channel
            return
        }
    }
}
proc Test {} {
    # The following channels don't cause a problem.
    #set f  [open NUL w]
    #set f [socket -server Accept 0]
    #set f [socket www.google.co.uk 80]
    # This will crash in TclFinalizeIOSubsystem
    set  f [open [file join [info nameofexecutable] boot.tcl] r]
    return [rechan [list RchanProc $f] 7]
}
if {!$tcl_interactive} {
    set c [Test]
    puts "opened $c"
    exit
}