Meaning of Device Class "00000000-0000-0000-0000-000000000000" while installing Device,...

Hi,

what exactly does this GUID "00000000-0000-0000-0000-000000000000" mean,
while the System installs a Device. If i ask for the Device Class Guid, i
get this for the
Device while it is on the early stage of installation,...

I think it means something like: The Device Class is not "know yet", or
something like that,...am i right...?

TIA,...

Regards

Kerem

--

 

it means that there is no class guid assigned yet (it is all zeros after
all)

d

 

Hi Doron,

ok thanks,..

Regards

K.

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Hi Doron,

just one more question: I found a device in my Device Enumeration
that is not shown in the device manager. What kind of device is that?
The Device Manager does not even show it with
DEVMGR_SHOW_NONPRESENT_DEVICES=1

Its Instance ID is: "HTREE\ROOT\0"

I dont know what this device is and what it is good for,...

Regards

Kerem

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this is the root of the entire pnp tree

d

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Hi Doron,

thanks for the reply. What would happen if i remove
this entry with PNP Functions?


Regards

K.

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i don't think you can remove it, it is really a pseudo device.

d

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Hi Doron,

you are very helpful, thats honorable!
I have one more question: Are the Device Class GUIDs always
the same ony any machine in the world and on any Windows OS
starting from W2K over XP to Vista? I need to know this, because
my application builds on the Device Classes GUIDs,...

Here is a Dump from my App:

12.08.2008 01:41:52 :: All Available Devices Classes on: HYBRID-DEV filter
by "D;K;N;P;S;U"

{4d36e968-e325-11ce-bfc1-08002be10318}::[Display]::Grafikkarte
{4d36e96b-e325-11ce-bfc1-08002be10318}::[Keyboard]::Tastaturen
{4d36e972-e325-11ce-bfc1-08002be10318}::[Net]::Netzwerkadapter
{4d36e973-e325-11ce-bfc1-08002be10318}::[NetClient]::Netzwerkclient
{4d36e974-e325-11ce-bfc1-08002be10318}::[NetService]::Netzwerkdienst
{4d36e975-e325-11ce-bfc1-08002be10318}::[NetTrans]::Netzwerkprotokoll
{4d36e977-e325-11ce-bfc1-08002be10318}::[PCMCIA]:CMCIA-Adapter
{4d36e97d-e325-11ce-bfc1-08002be10318}::[System]::Systemgeräte
{4d36e97e-e325-11ce-bfc1-08002be10318}::[Unknown]::Andere Geräte

Especially the "Unknown" Class is very important to me,...

Thanks in advance Doron,...

Regards

Kerem

--

 

Yes, there are defined in devguid.h. To identify GUID
it's helpful to convert from the 'readable' format
into the '#define' format. I've made a little ugly
tool for this.
http://www.uwe-sieber.de/files/guid_to_def.zip

Once you have the #define format you can search all
the WDK header files for it to discover the meaning
of the GUID.


Uwe

 

yes, microsoft defined class GUIDs are constant (otherwise how would a 3rd
party be able to use them reliably?). a 3rd party can choose to define its
own class GUID in which case there are no rules/guarantees as to its value

d

 

Hi Uwe, hi Doron

nice, thanks for the information,...the point is that my
aplication really depends on the guids, so this info
is really good to me,...

Regards

Kerem

--

 

Hi Doron,

in fact you can! I did 2 Minutes ago, but it has been automatically
redetected and reinserted into the device tree. It can be deleted, this
is fact!

Regards

K.

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