ColinChang.InteropNet 1.0.1

InteropNet

The library allows you to work with native libraries. Standard approach with the DllImport attribute may be inconvenient if you want to build AnyCPU assembly with MS.NET/Mono support. The Interoptor class can generate implementation of interface with target signatures of native methods.

For example, let's create a native library (NativeLib) with the function int sum(int a, int b) { return a + b; } and build it in four configuration (Windows/Unix, x86/x64):

x86/NativeLib.dll
x86/libNativeLib.so
x64/NativeLib.dll
x64/libNativeLib.so

Now we can write the following code:

public interface INative
{
    [RuntimeDllImport("NativeLib", CallingConvention = CallingConvention.Cdecl, EntryPoint = "sum")]
    int Sum(int a, int b);
}

class Program
{
    static void Main()
    {
        var native = Interoptor.Create<INative>();
        Console.WriteLine("2 + 3 = " + native.Sum(2, 3));
    }
}

In the program, we declared interface INative with signatures of the target native methods. Each signature should be marked with the RuntimeDllImport attribute with name of a native library and other options. The instance of Interoptor helped us to create instance of the INative interface on the fly. The implementation of the sum method call corresponding native method from library that correspond to current architecture and OS. The Interoptor generates the following code:

namespace Interoptor.NativeInstance
{
  [UnmanagedFunctionPointer(CallingConvention.Cdecl, BestFitMapping = false, CharSet = (CharSet) 0, SetLastError = false, ThrowOnUnmappableChar = false)]
  [StructLayout(LayoutKind.Auto, CharSet = CharSet.Auto)]
  public delegate int SumDelegate(int a, int b);

  public class NativeImplementation : INative
  {
    private SumDelegate SumField;

    public NativeImplementation(LibraryLoader loader)
    {
      IntPtr dllHandle = loader.LoadLibrary("NativeLib", (string) null);
      this.SumField = (SumDelegate) Marshal.GetDelegateForFunctionPointer(loader.GetProcAddress(dllHandle, "sum"), typeof (SumDelegate));
    }

    public int Sum(int a, int b)
    {
      return this.SumField(a, b);
    }
  }
} 

As a result, we received a single .NET cross-platform AnyCPU-program with calls of native methods because of the LibraryLoader class loaded handles for specific user environment.

Platform

Only Windows and Linux(CentOS 8,Debian 9,Ubuntu 20.04 are tested) are supported.

We use libdl.so.2 to load library(*.so), it means some Linux release version like alpine doesn't support it.

the libdl.so.2 file is a library in most of Linux. Generally,it's in a system path configured in system environment variables.

Thanks

https://github.com/AndreyAkinshin/InteropDotNet