On Mon, May 24, 2010 at 20:08, Alan Ott [off-list ref] wrote:

Several weeks ago I had need of libudev, and was unable to find very
much documentation for it on the web.

I have created a guide on how to use libudev, which also provides some
background information on /dev, Sysfs, and why this kind of thing is needed.

Please check it out and provide comments, as I'm sure there are things
which I have gotten wrong or omitted.

The guide can be found here:
   http://www.signal11.us/oss/udev/

Enumeration and monitoring should be in one example, I guess -- that's
what people are supposed to do today. Before starting to enumerate,
software should subscribe to events. This makes the handle
coldplug/hotplug properly, makes it handle duplicate events properly,
and all other sorts of cases, which software should handle today.

Also "change" is not necessarily a "property" change, it can be any
event, that a device has changed its state, it will only in  a few
cases be visible in /sys. The most prominent example is "media
changed" event for SCSI devices, and we forward them to the block
device. There will never change anything in /sys before or after the
event.

Kay