udev_device_get_sysattr_value upon device remove

udev_device_get_sysattr_value upon device remove

[Stefan Harjes]

Hi folks,

when I get an udev_device from the udev_monitor, because the device has been 
unplugged, the 'udev_device_get_sysattr_value()' call returns 'null' (in my 
case I was looking for the "serial" of an usb_device). From my understanding 
this value should still be cached, even if the device is already removed?

Is there any other way to get this value?

Best

Stefan

Re: udev_device_get_sysattr_value upon device remove

[Kay Sievers]

On Fri, Dec 3, 2010 at 20:19, Stefan Harjes <stefan.harjes@gmx.net> wrote:
> when I get an udev_device from the udev_monitor, because the device has been
> unplugged, the 'udev_device_get_sysattr_value()' call returns 'null' (in my
> case I was looking for the "serial" of an usb_device). From my understanding
> this value should still be cached, even if the device is already removed?

Devices which are removed have no attributes, not in sysfs, not
anywhere else. They are just gone.

> Is there any other way to get this value?

You have to store stuff you want to remember in the udev database,
which is available during remove, everything else is not.

Kay