[Tcl-bugs] [tcl] (Ticket 2413550fff - Change) Avoid double-open of serial ports on Windows

[<tcl...@tc...>]

Repository: http://core.tcl.tk/tcl

Change Notification For
  [Avoid double-open of serial ports on Windows]
  Ticket   http://core.tcl.tk/tcl/tktview?name=2413550fffffffffffffffffffffffffffffffff
  Artifact http://core.tcl.tk/tcl/tinfo?name=4fea181e24e859144d53334703c640097536fce1
  On       2014-01-30T11:04:54
  By       oehhar

Changed Fields
  assignee: aku
  closer:   nobody
  comment:  Currently, opening a serial port on Windows involves a double-open:
            (1) open generically (2) check the handle for serialness (3) reopen
            with OVERLAPPED flag if serial.

            This causes trouble in some setups where the open/close (and its
            timing) is not transparent to the underlying driver, like bluetooth
            RFCOMM profile. See

            http://groups.google.fr/group/comp.lang.tcl/tree/browse_frm/thread/9f2f
            29db7b5864fd/fd6d04dbc15d8575?rnum=1&_done=%2Fgroup%2Fcomp.lang.tcl%2Fb
            rowse_frm%2Fthread%2F9f2f29db7b5864fd%2Fdd17ccbb0019ed90%3F#doc_fd6d04d
            bc15d8575

            for a concrete example.

            A simple and efficient solution is to use a "name hint" to detect COM
            ports by their filename instead of resorting to a syscall to detect
            serialness after the fact.

            Rolf Shroedter has suggested that at least the two following patterns
            should be detected:

            COM[0-9]:?  \\\\.\\COM[0-9]+:?

            It also turns out that the first one should be applied to the [file
            tail], since \\foo\\bar\\COM4 is also a valid serial port reference in
            Windows.

            However, we believe that a good strategy should be to make only a
            reasonable effort in that direction, leaving tricky cases handled by
            the current behavior; this in order not to spoil the performance of
            [open] for non-serials.

            A patch will be uploaded shortly to support just the above two
            patterns.
  icomment: Patch applied for tcl 8.5 in branch [84307fe13f]
  login:    oehhar
  severity: Minor
  username: oehhar