Re: Serial port arbitration (UUCP device locking protocol?)
Re: Serial port arbitration (UUCP device locking protocol?)
- Subject: Re: Serial port arbitration (UUCP device locking protocol?)
- From: Dan Bernstein <email@hidden>
- Date: Sat, 12 Feb 2005 10:43:34 +0200
Thanks. That's something, but not quite what I'd hoped for. Is there a
way that I could tell when another program has opened the "call-out
device", and more importantly, when it has closed it, so that I can
put the modem back into a known state?
-- Dan
On Fri, 11 Feb 2005 12:23:24 -0800, Mike Smith <email@hidden> wrote:
> > I couldn't find any documentation or discussion of serial port
> > arbitration in darwin or Mac OS X. The situation is the classic one: I
> > want my program to listen on the modem port but yield it to any other
> > program wishing to use it. The efax man page mentions the "UUCP device
> > locking protocol", but this appears to be useful only if all other
> > applications adhere to it. Is Open Transport's arbitration mechanism
> > supported under Mac OS X? If so, what does it use on the darwin level?
> >
> > I also wouldn't want the fact that I'm listening on the device to
> > interfere with sleep. Do I need to listen for system power
> > notifications and close the port when the system is requesting
> > permission to go to sleep?
>
> As with all BSDs, you should open the call-in device (/dev/tty*).
>
> Programs that want to use the line to call out will open the call-out
> device (/dev/cu*)
>
> Typically, this means you open /dev/tty.modem, and others will open
> /dev/cu.modem.
>
> Having the call-in device open should not prevent the system from
> sleeping.
>
> = Mike
>
>
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