Example of PInvoke from Linux with .NET Core

PInvokeSamples.cs

using System.Runtime.InteropServices;

namespace PInvokeSamples {
    public static class Program {

        // Import the libc and define the method corresponding to the native function.
        [DllImport("libc.so.6")]
        private static extern int getpid();

        public static void Main(string[] args){
            // Invoke the function and get the process ID.
            int pid = getpid();
            Console.WriteLine(pid);
        }
    }
}

How do I call a c++ library I created from asp.net core in windows? I get a BadImageFormatException. In RC1 I was able to do it, but am not sure where to place the dll in asp.net core.

@martinwoodward What is the alternative for following code:
This code i m using in Windows. I want alternate code for Linux(RHEL7).

`using System.Runtime.InteropServices;

namespace PInvokeSamples {
public static class Program {

    // Import the kernel32.dll and define the method corresponding to the native function.
    [DllImport("kernel32.dll")]
    private static extern uint GetCurrentThreadId();

    public static void Main(string[] args){
        // Invoke the function and get the process Thread ID.
        uint tid = GetCurrentThreadId();
        Console.WriteLine(tid);
    }
}

}`