Try/finally in device drivers

NTDEV
1

Hello,

Monday, October 16, 2000, 11:12:52 AM, you wrote:

http://www.ddj.com/ftp/1998/1998_03/ntdd.zip/

There are few examples of device drivers written with WinDK and
DriverWorks on this link.

I do see __try/__finally statements in the code. Is it possible? few
weeks ago ecerybode told that impossible to use C++ exception control
statements in the drivers.

Best regards,
Sergey

2

> From: Sergey Kipnis [mailto:xxxxx@twins.com.pl]

I do see __try/__finally statements in the code. Is it possible? few
weeks ago ecerybode told that impossible to use C++ exception control
statements in the drivers.

__try/__finally aren’t C++ exceptions. Instead of it’s the so called
Structured Exception Handling (SEH), an OS mechanism supported by the MS
compiler at least.
The main difference to C++ exceptions is that destructors will not be
executed during stack unwinding and that C++ exceptions haven’t finally
block.
Refer to MSDN documentation for further information.

3

Yes, it can be done.
There is no contradiction: the __try __finally statements are not part of
C++ exception handling. That is called Structured Exception Handling
(supported by Visual C++) and can be used in driver developement (I’ve done
it myself). Personally I consider it better than C++ exception handling
since it’s available even in C code, not only C++.
For more information look in MSDN - start point can be “SEH” in the index.

----- Original Message -----
From: “Sergey Kipnis”
To: “NT Developers Interest List”
Sent: Monday, October 16, 2000 1:04 PM
Subject: [ntdev] Try/finally in device drivers

> Hello,
>
> Monday, October 16, 2000, 11:12:52 AM, you wrote:
>
> http://www.ddj.com/ftp/1998/1998_03/ntdd.zip/
>
> There are few examples of device drivers written with WinDK and
> DriverWorks on this link.
>
> I do see try/ finally statements in the code. Is it possible? few
> weeks ago ecerybode told that impossible to use C++ exception control
> statements in the drivers.
>
> Best regards,
> Sergey

4

Actually the __try/__finally construct should be considered more of a
“structured goto” rather than exception handling, as this from doesn’t
handle exceptions. Instead it provides a very nice way to format complex
loops and functions so that they have a single entry/single exit semantics.
__try/__except is the SEH exception handler.

-----Original Message-----
From: Paul Balanoiu [mailto:xxxxx@home.ro]
Sent: Monday, October 16, 2000 8:50 AM
To: NT Developers Interest List
Subject: [ntdev] Re: Try/finally in device drivers

Yes, it can be done.
There is no contradiction: the __try __finally statements are not part of
C++ exception handling. That is called Structured Exception Handling
(supported by Visual C++) and can be used in driver developement (I’ve done
it myself). Personally I consider it better than C++ exception handling
since it’s available even in C code, not only C++.
For more information look in MSDN - start point can be “SEH” in the index.

----- Original Message -----
From: “Sergey Kipnis”
To: “NT Developers Interest List”
Sent: Monday, October 16, 2000 1:04 PM
Subject: [ntdev] Try/finally in device drivers

> Hello,
>
> Monday, October 16, 2000, 11:12:52 AM, you wrote:
>
> http://www.ddj.com/ftp/1998/1998_03/ntdd.zip/
>
> There are few examples of device drivers written with WinDK and
> DriverWorks on this link.
>
> I do see try/ finally statements in the code. Is it possible? few
> weeks ago ecerybode told that impossible to use C++ exception control
> statements in the drivers.
>
> Best regards,
> Sergey

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5

Don’t confuse C++'s exception with Win32’s Structured Exception Handling.
I’ve made that mistake more than a few times.

Greg

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Sergey Kipnis
Sent: Monday, October 16, 2000 6:05 AM
To: NT Developers Interest List
Subject: [ntdev] Try/finally in device drivers

Hello,

Monday, October 16, 2000, 11:12:52 AM, you wrote:

http://www.ddj.com/ftp/1998/1998_03/ntdd.zip/

There are few examples of device drivers written with WinDK and
DriverWorks on this link.

I do see __try/__finally statements in the code. Is it possible? few
weeks ago ecerybode told that impossible to use C++ exception control
statements in the drivers.

Best regards,
Sergey

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To unsubscribe send a blank email to $subst(‘Email.Unsub’)

6

> I do see __try/__finally statements in the code. Is it possible? few

weeks ago ecerybode told that impossible to use C++ exception control
statements in the drivers.

__try/__finally is a C exception control, not C++ one. This is an MS
addition to C language.
File system drivers and cache manager rely on __try/__finally heavily.

Max

7

> it myself). Personally I consider it better than C++ exception handling

since it’s available even in C code, not only C++.

BTW - mixing __try/__catch and C++ try/catch in the same source file is
impossible.
The latter requires “Enable Unwind Semantics” compiler option (enable
destructor calls while bypassing C++ exceptions) - which contradicts the
former.

Max