How can I call a C++ function from C#?

Question

How can I call a C++ function from C# .NET?

Answer 1

1. compile the C++ function into a dll and use P/Invoke

   or

2. compile the C++ function into a C++/CLI assembly, wrap in a managed C++ class, and then treat like any other assembly (add a reference, use a using statement and call the class)

Answer 2

There is a related discussion here.

Answer 3

Or

Create a COM wrapper and then reference it from .NET