Calling C# code from C++

Question

I need to be able to invoke arbitrary C# functions from C++. http://www.infoq.com/articles/in-process-java-net-integration suggests using ICLRRuntimeHost::ExecuteInDefaultAppDomain() but this only allows me to invoke methods having this format: int method(string arg)

What is the best way to invoke arbitrary C# functions?

Answer 1

There are several ways for a C++ application to invoke functions in a C# DLL.

1. Using C++/CLI as an intermediate DLL
   • http://blogs.microsoft.co.il/sasha/2008/02/16/net-to-c-bridge/
2. Reverse P/Invoke
   • http://tigerang.blogspot.ca/2008/09/reverse-pinvoke.html
   • http://blogs.msdn.com/b/junfeng/archive/2008/01/28/reverse-p-invoke-and-exception.aspx
3. Using COM
   • http://msdn.microsoft.com/en-us/library/zsfww439.aspx
4. Using CLR Hosting (ICLRRuntimeHost::ExecuteInDefaultAppDomain())
   • http://msdn.microsoft.com/en-us/library/dd380850%28v=vs.110%29.aspx
   • http://msdn.microsoft.com/en-us/library/ms164411%28v=vs.110%29.aspx
   • https://stackoverflow.com/a/4283104/184528
5. Interprocess communication (IPC)
   • How to remote invoke another process method from C# application
   • http://www.codeproject.com/Tips/420582/Inter-Process-Communication-between-Csharp-and-Cpl
6. Edit: Host a HTTP server and invoke via HTTP verbs (e.g. a REST style API)

Answer 2

Compile your C++ code with the /clr flag. With that, you can call into any .NET code with relative ease.

For example:

#include <tchar.h> #include <stdio.h>  int _tmain(int argc, _TCHAR* argv[]) {     System::DateTime now = System::DateTime::Now;     printf("%d:%d:%d\n", now.Hour, now.Minute, now.Second);      return 0; } 

Does this count as "C++"? Well, it's obviously not Standard C++ ...