473,847 Members | 1,492 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Wrap old C DLL in new unmanaged C++ / Managed C++ DLL

I have an old C DLL that I want to access via C#.

I'm doing this via an outer DLL that wraps the old C DLL in an unmanaged
C++ class, which is in turn wrapped in a Managed C++ class. Both these
unmanaged C++ and managed C++ classes are compiled into a single assembly
(DLL) that is accessed by C#.

[C DLL] <--> [Unmanaged C++ / Managed C++] <--> [C# app]
old dll new C++ assembly app

I don't want to use standard Interop methods. I'm trying to do all the
direct access to the old C DLL with unmanaged C++. The data types in the
old C DLL are relatively complex, so I'm encapsulating the cluttered
legacy stuff in the new unmanaged C++ class.

IOW, I'll usually only be passing ints and a couple strings between the
unmanaged and managed sides.

In general, this approach works, but I'm getting occasional runtime errors
that I can't explain. Could someone post or refer me to a very simple
example that does this with even a single function? Say, take a function
from a stock Windows DLL and show a correct unmanaged C++ class
and managed C++ class that will wrap it correctly.

Thanks for any insights you can provide.
Nov 17 '05 #1
3 2005
On Sun, 09 Jan 2005 21:52:43 -0500, _BNC <_B**@nospam.co m> wrote:
I have an old C DLL that I want to access via C#.

I'm doing this via an outer DLL that wraps the old C DLL in an unmanaged
C++ class, which is in turn wrapped in a Managed C++ class. Both these
unmanaged C++ and managed C++ classes are compiled into a single assembly
(DLL) that is accessed by C#.

[C DLL] <--> [Unmanaged C++ / Managed C++] <--> [C# app]
old dll new C++ assembly app

I don't want to use standard Interop methods. I'm trying to do all the ^^^^^^^^^^
Oops... I meant I don't want to use PInvoke. I'm using the flat 'IJW'
model.

direct access to the old C DLL with unmanaged C++. The data types in the
old C DLL are relatively complex, so I'm encapsulating the cluttered
legacy stuff in the new unmanaged C++ class.

IOW, I'll usually only be passing ints and a couple strings between the
unmanaged and managed sides.

In general, this approach works, but I'm getting occasional runtime errors
that I can't explain. Could someone post or refer me to a very simple
example that does this with even a single function? Say, take a function
from a stock Windows DLL and show a correct unmanaged C++ class
and managed C++ class that will wrap it correctly.

Thanks for any insights you can provide.


Nov 17 '05 #2
_BNC wrote:
I have an old C DLL that I want to access via C#.

[C DLL] <--> [Unmanaged C++ / Managed C++] <--> [C# app]
old dll new C++ assembly app

In general, this approach works, but I'm getting occasional runtime errors
that I can't explain.


You may be running into the dreaded Mixed DLL Loading problem:

http://msdn.microsoft.com/library/de...ingProblem.asp

See if this helps. If not, try giving a minimal code example that causes
the error, or explaining some more detail of your setup.
--
Derrick Coetzee, Microsoft Speech Server developer
This posting is provided "AS IS" with no warranties, and confers no
rights. Use of included code samples are subject to the terms
specified at http://www.microsoft.com/info/cpyright.htm
Nov 17 '05 #3
I'm getting some errors in an app that makes use of a mixed-mode DLL
for transitioning between .NET and an old native C DLL:

[C DLL] <--> [Unmanaged C++ / Managed C++] <--> [C# app]

I believe I got my initial info from an older Wrox book, so the problems
may have stemmed from there.

Is there a good source of info or examples of mixed Unmanaged/Managed
DLL's? Books, pointers to MSDN articles?

Nov 17 '05 #4

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

1
741
by: Bob Rock | last post by:
Hello, in the last few days I've made my first few attempts at creating mixed C++ managed-unmanaged assemblies and looking aftwerwards with ILDASM at what is visible in those assemblies from a managed point-of-view I've noticed that: 1) for each managed and unmanaged C function (not C++ classes) I get a public managed static method (defined on a 'Global Functions' class) in the generated assembly with an export name of the form...
5
3632
by: Chris Kiechel | last post by:
I am writing a .NET Windows application and it needs to perform DDE calls to a legacy system. I created a C++ unmanaged class that performs the actual DDE connection and communication. However, I need .NET to instantiate this object and somehow allow the this object to callback to .NET. So, my question is: 1. How can a managed class instantiate and unmanaged class?
4
40066
by: Rachel Suddeth | last post by:
What is the difference between a managed/unmanaged resource, and how do you tell which is which? I'm trying to understand how to write some Dispose() methods, and we are supposed to put code that deals with managed in one place, and code that deals with unmanaged in another place, but I can't seem to find anything that clearly explains what that means. I think if I used a Windows API function to optain a handle, that handle would be an...
1
1887
by: knormand | last post by:
I have an older MFC C++ app with some new Managed C++ being thrown in. Recently I turned on the /clr flag for one of my old .cpp files. I then placed '#pragma unmanaged' just below my #include statements near the top of the file. These headers contain older unmanaged class declarations. When running I discovered a new bug, a crash, at a point in execution that was nowhere near any code that's been touched in quite a while. After hunting down...
2
2062
by: Bob Rock | last post by:
Hello, in the last few days I've made my first few attempts at creating mixed C++ managed-unmanaged assemblies and looking afterwards with ILDASM at what is visible in those assemblies from a managed point-of-view I've noticed that: 1) for each managed and unmanaged C function (not C++ classes) I get a public managed static method (defined on a 'Global Functions' class) in the generated assembly with an export name of the form
3
3516
by: zhphust | last post by:
I want to convert a object of a managed class to a unmanaged structure that has the same member with that managed class. Can anybody tell me how i can do it? Thanks in advance. -- zhphust ------------------------------------------------------------------------
1
1661
by: Sparhawk | last post by:
Hi, my company is going to migrate a large VC++ application to .NET to make use of Windows Forms (the old class library is not updated any more). We are not planning to migrate the rest of the code which works well. I understand the basic concept: our code is unmanaged, Windows Forms is Managed and Unmanaged may not call Managed code. I read about Wrappers, PInvoke, Runtime Callable Wrappers for COM and about It just
2
2564
by: =?Utf-8?B?Y2hyaXNiZW4=?= | last post by:
Hi, I have some C++ static library which I would like to wrap and use in C# applications. It appears that I have two options. 1. Wrap the static library as dynamic library (dll), use unmanaged C++. Then invoke the method in C# by DllImport. 2. Wrap the static lib using managed C++, which will create a dll as .NET assembly, so C# project can directly use it as reference and call methods
2
12371
by: Jon Slaughter | last post by:
How difficult is it for one to integrate unmanaged C++ into C#? I know for functions one can use DLLimport but how does one go about doing it for classes? Do I have to completely reimplement the classes in managed C++ as a wrapper to the unmanaged C++ classes or is there an easier way? Essentially what I have done is written a C++ kernel mode driver and I want to use it from my C# program. Because it requires some setup outside the...
0
9734
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
10995
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
10654
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
10718
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
9493
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
0
7061
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5915
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
4540
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
3
3168
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.