Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Home NTDEV

Before Posting...

Please check out the Community Guidelines in the Announcements and Administration Category.

More Info on Driver Writing and Debugging


The free OSR Learning Library has more than 50 articles on a wide variety of topics about writing and debugging device drivers and Minifilters. From introductory level to advanced. All the articles have been recently reviewed and updated, and are written using the clear and definitive style you've come to expect from OSR over the years.


Check out The OSR Learning Library at: https://www.osr.com/osr-learning-library/


RE: Can we declare a variable as 'int' in the driver --???

OSR_Community_UserOSR_Community_User Member Posts: 110,217
Come on guys. Someone says their code works in debug, and fails
on a free build. Then they claim that it is because one of the most
basic features of C is not working. But this is a kernel driver, and
if they are actually making an exact diagnosis, rather than guessing,
the tool they are probably using to look at this stuff is Windbag.
There is NO WAY this is a compiler bug or anything close to it.

-DH
PS I hope I don't have to eat those words.

----- Original Message -----
From: "Roddy, Mark" <[email protected]>
To: "NT Developers Interest List" <[email protected]>
Sent: Wednesday, June 21, 2000 1:50 PM
Subject: [ntdev] RE: Can we declare a variable as 'int' in the driver ???


If the compiler is treating int as unsigned it is broken.

> -----Original Message-----
> From: Duncan Hume [mailto:[email protected]]
> Sent: Wednesday, June 21, 2000 12:18 PM
> To: NT Developers Interest List
> Subject: [ntdev] RE: Can we declare a variable as 'int' in
> the driver ???
>
>
> One thing to bear in mind is that the storage is irrelevant, it is the
> functions/macnine code instructions that determine if you are
> working in
> signed or unsigned. Check the machine code listing to see if the
> instructions used in the Free build looks the same as the
> Checked.. Try
> changing the loop to >-1 and see what code is produced.
>
> Duncan
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> Sent: 21 June 2000 16:33
> To: NT Developers Interest List
> Subject: [ntdev] RE: Can we declare a variable as 'int' in the driver
> ???
>
>
> >I don't see what difference iCount being signed or not
> When a I used to be a pupil I was given a task by my teacher
> to find a bug
> in this code:
>
> ULONG uCount;
> for(uCount = 10; uCount >= 0; uCount--)
> {
> // ...
> }
>
> And I've found it then :) This loop is infinite, 'cause
> uCount is always >=
> 0.
>
> ----------
> ??: Paul Bunn[SMTP:[email protected]]
> ?????: NT Developers Interest List
> ??????????: 21 ???? 2000 ?. 19:16
> ????: NT Developers Interest List
> ????: [ntdev] RE: Can we declare a variable as 'int'
> in the driver ???
>
> I don't see what difference iCount being signed or not would
> make to the for
> loop.
> int normally is equivalent to LONG. You should be able to
> define iCount as
> LONG or ULONG and it shouldn't make any difference to that
> particular loop.
> The only difference I can think of is that in the free build
> it is likely
> that iCount may not be assigned storage at all, but may just live as a
> register value (depending on what you're doing with it).
> It's also possible
> that it's a compiler bug, though that is rare these days. I
> would tend to
> recommend debugging the free build and looking at the disassembly.
>
> Regards,
>
> Paul Bunn, UltraBac.com, 425-644-6000
> Microsoft MVP - WindowsNT/2000
> http://www.ultrabac.com
>
>
> -----Original Message-----
> From: Eshanye [mailto:[email protected]]
> Sent: Wednesday, June 21, 2000 7:27 AM
> To: NT Developers Interest List
> Subject: [ntdev] Can we declare a variable as 'int' in the driver ???
>
>
> Hi,
>
> I have declared a variable as 'int' in my driver. This
> variable is used
> as an index inside a for loop. something like this:-
>
> int iCount;
>
> for(iCount = 3; iCount >= 0; iCount--)
> {
>
> blah.. blah..
>
> }
>
> This is a part of DriverEntry....
>
> Now this driver is working very fine if built as a checked
> build. But it
> wont get loaded if it is built as a free build. Because iCount is
> behaving as ULONG. and therefore it is in an infinite loop and so the
> driver is not getting loaded at all.
>
> [I know that I can change the for loop to serve my purpose, but ...
> why...]. I declared iCount as LONG. But still the same behavior !!!!!
> [LONG is supposed to be signed long right ????] What is happening ?
>
>
> ---
> You are currently subscribed to ntdev as: [email protected]
> To unsubscribe send a blank email to $subst('Email.Unsub')
>
> ---
> You are currently subscribed to ntdev as: [email protected]
> To unsubscribe send a blank email to $subst('Email.Unsub')
>

---
You are currently subscribed to ntdev as: [email protected]
To unsubscribe send a blank email to $subst('Email.Unsub')
Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. Sign in or register to get started.

Upcoming OSR Seminars
OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!
Kernel Debugging 13-17 May 2024 Live, Online
Developing Minifilters 1-5 Apr 2024 Live, Online
Internals & Software Drivers 11-15 Mar 2024 Live, Online
Writing WDF Drivers 20-24 May 2024 Live, Online