lock access to serial port

[Andra]

I tried ready-made commands for file locking, and turned to that LCK
file just in case some permissions are wrong and that's the reason the
commands fail.

On 19 Marts, 15:43, Grant Edwards <gra... at visi.com> wrote:
> On 2008-03-18, kkadr... at gmail.com <kkadr... at gmail.com> wrote:
>
> > how to get ttyS0 serial port for exclusive access? I have a python
> > script that uses this device with AT commands. I need that two
> > instances can call simultaneosuly this python script but only one of
> > them gets the device. I tried fcntl.flock, it was just ignored, put
> > writtable file LCK..ttyS0 in /var/lock,
>
> Using a lock file is the traditional method of providing
> mutually exclusive access to a serial port.
>
> > tried ioctl (but I may not know what are appropriate
> > arguments), googled half a day for various phrases, error
> > messages etc....without success.
>
> It's unclear what "without success" means.  Lockfiles have been
> used for decades, and they work fine as long as all of the
> applications follow the rules.
>
> --
> Grant