Use LegacyWrapper from a 64bit DLL?

[nurbles]

I'm hoping to create something to stick between an updated-to-64-bit product (A) that will allow it to still use an old 32-bit product (B) that we still use. Product A expects product B to be a 64-bit DLL, so I'm hoping that I can use LegacyWrapper to produce a DLL (that Product A can call) to act as a 64 bit wrapper for the old 32 bit DLL. LegacyWrapper sounds perfect ... except I'm a C programmer (not C++ or C#) and Visual Studio doesn't seem to have a template for a C# DLL and event if it did, I'm not sure all the exported functions and types would match for both the exported functions and the 32-bit functions to be called.

Is what I'm hoping to do possible or must I take (at least) a few months to learn to create all the COM things necessary to create this from scratch?

[zalintyre]

I am a little bit confused what product B is... 32bit or 64 bit?

And the general answer is that LegacyWrapper supports 32bit and 64bit Windows DLLs (not .NET class libraries).

[nurbles]

Sorry, "Product B" is "the old 32-bit DLL" that I need to use from a now 64 bit program. So my plan was to write a 64 bit DLL with the same interface as the old 32-bit DLL had, and have my 64-bit DLL find a way to call the 32-bit, hopefully using LegacyWrapper, but it looked like I needed to code my DLL in C# in order to make the necessary declarations.

However, the more I look the trickier it may be because the calling convention for some of the functions includes an integer followed by a point to an array of [the previous parameter's value] number of elements. Sometimes more than one of those. And sometimes they are arrays of (64-bit) pointers. Would LegacyWrapper be able to deal with all of the pointer adjustments?

[zalintyre]

Please note that your application must be a managed (say: .NET, written in C# or VB.NET) application to use LegacyWrapper. It sounds like your application is built by some other technology?

However, LegacyWrapper supports different calling conventions like stdcall, cdecl and so on. Just have a look at the LegacyDllMethod class.

[nurbles]

I'm trying to build a wedge (my term) to put between the now 64 bit Visual Studio 2022 and our source control package, QVCSPro 3.10 (a 32 bit DLL from 2014). I have no source for either, but I do have the interface spec from Microsoft for source control provider DLLs, which is plain C. My 'wedge' could be anything that can present the appropriate C-style interface to Visual Studio and convert the parameters received into the appropriate C-style calls into the 32 bit DLL.

I think I've figured out all of the things I need to do (using Microsoft's COM method to call 32 bit from 64 bit), but I'm a Native C Windows programmer (yup, a dying breed, quite literally in my case) and I was hoping to find an easier way. (smile)

However, I may "cheat" the COM stuff and steal your named pipe idea (or perhaps TCP through localhost) to communicate between my 64bit DLL-client and my 32bit DLL-server.

Feel free to close (or even remove) this issue. Thanks for chatting with me!

[zalintyre]

So, if I understood you correctly, both sides of the communication are built as a "native" application (without .NET virtualization). If so, I'm afraid you cannot use LegacyWrapper.

Of course, you can build something with named pipes or other network communication yourself.

Kind regards Franz