C++/CLI Support in .Net Core

30
votes

Our project structure is like,

native.dll :- This contains pure native code written in c\c++. This native.dll exposes some functions using *def file.

Wrapper Library(wrapper.dll compiled with .Net framework v4.0) :- In order to use functionality of native.dll, a Wrapper lib(wrapper.dll) is written in C++\CLI using :clr\oldsyntax. This wrapper has all code of Interoperability and Marshalling.

Application(Console App v4.0) directly uses wrapper.dll to use functionality provided by native.dll.

Now this project needs to run in .Net Core. This means we will have an .Net Core application that will reference wrapper.dll that in turn will refer native.dll.

I know this will not directly work. But the issue is whether .Net Core(CoreCLR) supports C++\CLI (clr\oldsyntax) runtime environment ?

If no, what can be the possible solutions to this application work ?

4
c++-cliunmanaged.net-coremanaged-c++coreclr
@HansPassant :- You said "There are few practical platform targets that could execute that native code anyway", can you please elaborate this ? Do really mean there is no way currently to run these type of Projects under .Net Core ? – User1234
@HansPassant : thanx for this. Yes you are right, we selected .Net core as we want to run our dotnet code(wrapper.dll which in turn invokes native.dll) in linux. But as you said, as of now CoreCLR does support C++/CLI runtime thus all this does not seems feasible. I had actually gone through lot of msdn blogs for .Net core but none of them hinted me about C++\CLI integeration in .net core. So does .Net core team will really support this in near future or not ? – User1234
There are many scenarios where C++/CLI support for .NET Core would be very useful. For e.g., if you are working with cross-platform C++ code and want to interface it with a .Net business layer for faster development. I'm very surprised that MS hasn't provided this - it seems ideal. – Zesty
@hanspassant That’s really a bit simplified. What if that DLL happens to be a cross platform library that you can compile for Linux and macOS also? Such use cases clearly do exist and it would be nice to have C++/CLI to support them. – Per Lundberg
I have the same need, too, and is surprised that it's not supported already. – Weipeng L

4 Answers

12
votes

whether .Net Core(CoreCLR) supports C++\CLI (clr\oldsyntax) runtime environment ?

As far as I know there is no plan to support C++/CLI with .NET Core.

If no, what can be the possible solutions to this application work ?

You can (should) provide a C API. Mono e. g. supports P/Invoke and .NET Core also supports P/Invoke (see also this Stack overflow question and this DllMap related ticket).

7
votes

.net Core team will only commit (now?) to supporting C++/CLI for Windows only.

The intention was to deliver it for .net Core 3.0. While I haven't found explicit mention of it yet in the release notes, C++/CLI support was a prerequisite for delivering WPF (windows-only), which is now supported in .net Core 3.0.

Support mixed-mode assemblies on Windows - #18013

This issue (#18013) will track progress toward supporting loading and running mixed-mode assemblies on CoreCLR. The main goal is to provide support for WPF and other existing C++/CLI code on .NET Core. Some of the work will be dependent on updates to the MSVC compiler.

The github issue (#659) mentioned above by @Tomas-Kubes, Will CoreCLR support C++/CLI crossplat? - #659, is about cross-platform C++/CLI.

BTW, I am getting compiler warnings on "clr\oldsyntax" with VS2017/.net-4.7. So this compiler flag is already deprecated.

UPDATE: This isn't coming till .Net Core 3.1

5
votes

Officially announced eventually... (next wish... support linux @ .Net 5 ^^)

https://devblogs.microsoft.com/cppblog/the-future-of-cpp-cli-and-dotnet-core-3/

C++/CLI will have full IDE support for targeting .NET Core 3.1 and higher. This support will include projects, IntelliSense, and mixed-mode debugging (IJW) on Windows. We don’t currently have plans for C++/CLI for targeting macOS or Linux. Additionally, compiling with “/clr:pure” and “/clr:safe” won’t be supported for .NET Core.

The first public previews for C++/CLI are right around the corner. Visual Studio 2019 16.4 Preview 1 includes an updated compiler with “/clr:netcore”

Updat: From replied of origin url: "We are still working on the IDE and MSBuild integration, so I can’t share a sample project quite yet. Once it’s available, likely with 16.4 Preview 2 or 3"

(16.4 Preview1 cannot create C++/CLI with .NetCore project.)

191015 16.4 Preview2 Released. I'v tried asp.net core 3.1 with c++/CLI dll, it works. (need set plateform to x64 both asp.net core and c++/CLI dll)

3
votes

Another potential solution (though obviously quite a difficult task) if you want to stick with C++ (i.e. expose an OO interface to .NET) might be to have a look at CppSharp from the mono project. It is able to expose native C++ code through an automatically generated C# wrapper. It supports Windows, Linux as well as OSX. However, I don't know if the generated code can be compiled to a .NET standard target (didn't try to). I can only suppose it would because the generated code does not use any fancy API (it is basically interop and marshalling code); and, by the way, it is also possible to customize the generation process (although, once again, probably not an easy task).