NativeLong, Pointer and PointerType

[DeafMan1983]

Hello everyone,

I made simple wrapper against alternative to IntPtr like I saw problem by users like this.

You can test my library for DotNet 3.1
Visit my repository!
PS: I have tested with SDL2-CS with NativeLong = works fine - completely. X11 works fine with NativeLong , too.

Enjoy and happy coding!

[Clockwork-Muse]

@DeafMan1983 - What problem is this solving for users?

Note that there are proposals for a native-int type, which might cover some of that.

[tannergooding]

A native type was already implemented and will ship in C# 9 as nint and nuint.

[DeafMan1983]

But I have made class instance like class Window : NativeLong { ... }

@tannergooding great idea I already implemented in NativeLong ( if Statement with Windows in constructor. But why do I need nativeUint? But it is not important. I said NativeLong, Pointer and PointerType are from JNA ( Java Native Access ) for Java coding. Java works like C#.

But why does Java not have IntPtr or UIntPtr because it doesn't care it. C# should work like Java if you use instance of typedef structures or typedef objects should work with NativeLong.

I have made for X11 for example:

using System;
using System.Runtime.InteropServices;
using Native.Access;
using static TestX11.XLib;

namespace TestX11
{
    public static class XLib
    {
        public class Display : NativeLong
        {
            public Display(long value) : base(value)
            {
            }
        }

        public class Drawable : NativeLong
        {
            public Drawable(long value) : base(value)
            {
            }
        }

        public class Window : Drawable
        {
            public Window(long value) : base(value)
            {
            }
        }

        private const string LibX11 = "libX11.so.6";

        [DllImport(LibX11, EntryPoint = "XOpenDisplay")]
        private static extern long Internal_XOpenDisplay(string display_name);

        public static Display XOpenDisplay(string display_name)
        {
            return new Display(Internal_XOpenDisplay(display_name));
        }

        [DllImport(LibX11, EntryPoint = "XCloseDisplay")]
        private static extern void Internal_XCloseDisplay(long display);

        public static void XCloseDisplay(Display display)
        {
            Internal_XCloseDisplay(display.ToNative());
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Display display = XOpenDisplay(string.Empty);

            if (display == null)
            {
                Console.WriteLine("Error: Display can't load.\n");
            }
            else
            {
                Console.WriteLine("Success: Display loads.\n");
            }

            XCloseDisplay(display);
            Console.WriteLine("Success: Display closed.");
        }
    }
}

Result:

No Exception with IntPtr or Structure! That is why it works with long / int like Java made with X11.

Please download my Native.Access and compile to dll and try with WinApi. If you know how do you create implements with WinApi? I really want listen about Windows Users if it throws exception then you should tell me. Because I just am trying to resolve with cross platform class "NativeLong" and it works as well anything. Sorry I have not Windows 10. I use only Ubuntu 18.04.x.

[tannergooding]

.NET doesn't need Pointer and PointerType (outside generic type parameters and reflection) because having T* is already legal. If the native code takes a int*, you can just use int* in C#.

As for NativeLong, an API has already been approved to expose as System.Runtime.InteropServices.CLong: #13788
This will effectively be int on Windows and nint on Unix. It is only necessary for P/Invoke bindings that need to work on both Windows and Unix.

For something like Xlib which is largely Unix specific, you could just use nint instead and it would still be correct, it just wouldn't work on Windows (which is probably fine because the usecase on Windows is extremely limited).