Enclaves must be 100 percent native code and the enclave bridge functions must be 100 percent native code with C (and not C++) linkages, it is possible, indirectly, to make an ECALL into an enclave from .NET and to make an OCALL from an enclave into a .NET object.
Mixing Managed Code and Native Code with C++/CLI
Microsoft Visual Studio* 2005 and later offers three options for calling unmanaged code from managed code:
- Platform Invocation Services, commonly referred to by developers as P/Invoke:
- P/Invoke is good for calling simple C functions in a DLL, which makes it a reasonable choice for interfacing with enclaves, but writing P/Invoke wrappers and marshaling data can be difficult and error-prone.
- COM is more flexible than P/Invoke, but it is also more complicated; that additional complexity is unnecessary for interfacing with the C bridge functions required by enclaves
- C++/CLI offers significant convenience by allowing the developer to mix managed and unmanaged code in the same module, creating a mixed-mode assembly which can in turn be linked to modules comprised entirely of either managed or native code.
- Data marshaling in C++/CLI is also fairly easy: for simple data types it is done automatically through direct assignment, and helper methods are provided for more complex types such as arrays and strings.
- Data marshaling is, in fact, so painless in C++/CLI that developers often refer to the programming model as IJW (an acronym for “it just works”).
- The trade-off for this convenience is that there can be a small performance penalty due to the extra layer of functions, and it does require that you produce an additional DLL when interfacing with Intel SGX enclaves.
Please find the detailed information in the PDF and also i have shared sample code."