Re: problems in running application(ASYN)

["J. Lewis Muir" <jlmuir@anl.gov>]

zhangdemin99 wrote:
> Dear all,
>   I have built ASYN on my computer, but there are some problems when
> running application. It said: \dev/ttyS0 can't open Permission denied
>   Should I open the serial port in the Linux first or  is there  another
> problems? what should I do next?

Hi, Demin.

Do you have read and write permissions on the device file /dev/ttyS0?

Can you send the output of the following commands when run as the user
you are running your ASYN application as:

$ ls -alF /dev/ttyS0
$ groups

On some Linux systems, the /dev/ttyS* device files are readable and
writable by root and the uucp group. In order to be able to read and
write to these device files, you need to add your user to the uucp
group. This can be done with administrator privileges from an
administrative account management GUI likely provided with your Linux
distribution. It can also be done from the command line if you have the
usermod command.

A less secure approach is to make the /dev/ttyS0 device world readable
and writable (run as root or as root via sudo):

# chmod o+rw /dev/ttyS0

With this approach, however, if you install a kernel update or anything
that may rebuild the /dev tree, your permissions change on the
/dev/ttyS0 file may be lost so you'll have to go back and change it
again after such an update.

-lewis