Error

NTDEV
1

Hi all,
Iam writing the driver in .cpp file.I included the cpprt.cpp file and
cpprt.h file.I get a error like this.
“error LNK2001: unresolved external symbol __fltused”.
what does it mean.Help me.

Thanks&Regards
sobana.D

2

How do you build your driver…???
If you can explain this, we can see where things go wrong…
Give info on which OS,DDK,etc & what you are trying to do in cpprt.cpp
file…

Shiva P

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Sobana
Sent: Thursday, June 10, 2004 9:07 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Error

Hi all,
Iam writing the driver in .cpp file.I included the cpprt.cpp file and
cpprt.h file.I get a error like this.
“error LNK2001: unresolved external symbol __fltused”.
what does it mean.Help me.

Thanks&Regards
sobana.D

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@wipro.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

3

Sobana,

I think the __fltused symbol is one generated by the compiler indicating
that you’re using floating point operations.

For most of the time, drivers do not support using floating point operations
because the floating point state is not saved on user->kernel transition,
and also not when switching from one kernel task to another. Special care
has to be taken when using floating point in a driver, using the
KeSaveFloatingPointState to save the current state before you start your
calculations, and a KeRestoreFloatingPointState after you’ve finished the
calculation.

Note that using floating point may not be a direct operation of your source
code, it may be done by a library function that you include, but I suspect
that would cause more symbols to be unresolved, so I would guess that you’re
using floating point math in your code.

I’m not entirely sure how to solve this (other than the simple way of
avoiding float operations in the driver, it’s for most cases not needed).
Maybe you can give yourself a variable called _fltused somewhere, but beware
that I’m not sure how this is used, and what side effects this will have.

–
Mats

-----Original Message-----
From: Sobana [mailto:xxxxx@qmaxtech.com]
Sent: Thursday, June 10, 2004 4:37 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Error

Hi all,
Iam writing the driver in .cpp file.I included the
cpprt.cpp file and
cpprt.h file.I get a error like this.
“error LNK2001: unresolved external symbol __fltused”.
what does it mean.Help me.

Thanks&Regards
sobana.D

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@3dlabs.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

4

Search the NTDEV archives at

http://www.osronline.com/page.cfm?name=search

for “fltused”.

Chuck

----- Original Message -----
From: “Sobana”
Newsgroups: ntdev
To: “Windows System Software Devs Interest List”
Sent: Thursday, June 10, 2004 10:37 AM
Subject: [ntdev] Error

> Hi all,
> Iam writing the driver in .cpp file.I included the cpprt.cpp file
and
> cpprt.h file.I get a error like this.
> “error LNK2001: unresolved external symbol __fltused”.
> what does it mean.Help me.
>
> Thanks&Regards
> sobana.D
>
>
>
>
>
> —
> Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@cbatson.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>

5

The more basic problem is that he’s trying to link in the C++ runtime.

There are numerous reasons why you can’t do that. You will need to
reproduce the parts of it that you actually need.

Read http://www.microsoft.com/whdc/driver/kernel/KMcode.mspx for more
information on using C++ in kernel drivers.

Chuck Batson wrote:

Search the NTDEV archives at

http://www.osronline.com/page.cfm?name=search

for “fltused”.

Chuck

----- Original Message -----
From: “Sobana”
> Newsgroups: ntdev
> To: “Windows System Software Devs Interest List”
> Sent: Thursday, June 10, 2004 10:37 AM
> Subject: [ntdev] Error
>
>
>
>>Hi all,
>> Iam writing the driver in .cpp file.I included the cpprt.cpp file
>
> and
>
>>cpprt.h file.I get a error like this.
>>“error LNK2001: unresolved external symbol __fltused”.
>>what does it mean.Help me.
>>
>>Thanks&Regards
>>sobana.D
>>
>>
>>
>>
>>
>>—
>>Questions? First check the Kernel Driver FAQ at
>
> http://www.osronline.com/article.cfm?id=256
>
>>You are currently subscribed to ntdev as: xxxxx@cbatson.com
>>To unsubscribe send a blank email to xxxxx@lists.osr.com
>>
>
>
>

–
…/ray..

Please remove “.spamblock” from my email address if you need to contact
me outside the newsgroup.

6

I wondered about that. He can get the basics from me at www.hollistech.com
and I think numega has something freely downloadable runtime as well. If he
wants the whole ball of wax as in c++ exceptions, he needs to have a big
rethink.

=====================
Mark Roddy

-----Original Message-----
From: Ray Trent [mailto:xxxxx@synaptics.spamblock.com]
Sent: Thursday, June 10, 2004 12:38 PM
To: Windows System Software Devs Interest List
Subject: Re:[ntdev] Error

The more basic problem is that he’s trying to link in the C++ runtime.

There are numerous reasons why you can’t do that. You will need to reproduce
the parts of it that you actually need.

Read http://www.microsoft.com/whdc/driver/kernel/KMcode.mspx for more
information on using C++ in kernel drivers.

Chuck Batson wrote:

Search the NTDEV archives at

http://www.osronline.com/page.cfm?name=search

for “fltused”.

Chuck

----- Original Message -----
From: “Sobana”
> Newsgroups: ntdev
> To: “Windows System Software Devs Interest List”
> Sent: Thursday, June 10, 2004 10:37 AM
> Subject: [ntdev] Error
>
>
>
>>Hi all,
>> Iam writing the driver in .cpp file.I included the cpprt.cpp file
>
> and
>
>>cpprt.h file.I get a error like this.
>>“error LNK2001: unresolved external symbol __fltused”.
>>what does it mean.Help me.
>>
>>Thanks&Regards
>>sobana.D
>>
>>
>>
>>
>>
>>—
>>Questions? First check the Kernel Driver FAQ at
>
> http://www.osronline.com/article.cfm?id=256
>
>>You are currently subscribed to ntdev as: xxxxx@cbatson.com To
>>unsubscribe send a blank email to xxxxx@lists.osr.com
>>
>
>
>

–
…/ray..

Please remove “.spamblock” from my email address if you need to contact me
outside the newsgroup.

—
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@stratus.com To
unsubscribe send a blank email to xxxxx@lists.osr.com