IN_PKTINFO

using System;
using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct IN_ADDR
{
    public _S_un_e__Union S_un;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct IN_PKTINFO
{
    public IN_ADDR ipi_addr;
    public uint ipi_ifindex;
}

Imports System.Runtime.InteropServices

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
Public Structure IN_ADDR
    Public S_un As _S_un_e__Union
End Structure

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
Public Structure IN_PKTINFO
    Public ipi_addr As IN_ADDR
    Public ipi_ifindex As UInteger
End Structure

import ctypes
from ctypes import wintypes

class IN_ADDR(ctypes.Structure):
    _fields_ = [
        ("S_un", _S_un_e__Union),
    ]

class IN_PKTINFO(ctypes.Structure):
    _fields_ = [
        ("ipi_addr", IN_ADDR),
        ("ipi_ifindex", wintypes.DWORD),
    ]

#[repr(C)]
pub struct IN_ADDR {
    pub S_un: _S_un_e__Union,
}

#[repr(C)]
pub struct IN_PKTINFO {
    pub ipi_addr: IN_ADDR,
    pub ipi_ifindex: u32,
}

import "golang.org/x/sys/windows"

type IN_ADDR struct {
	S_un _S_un_e__Union
}

type IN_PKTINFO struct {
	ipi_addr IN_ADDR
	ipi_ifindex uint32
}

type
  IN_ADDR = record
    S_un: _S_un_e__Union;
  end;

  IN_PKTINFO = record
    ipi_addr: IN_ADDR;
    ipi_ifindex: DWORD;
  end;

const IN_ADDR = extern struct {
    S_un: _S_un_e__Union,
};

const IN_PKTINFO = extern struct {
    ipi_addr: IN_ADDR,
    ipi_ifindex: u32,
};

type
  IN_ADDR {.bycopy.} = object
    S_un: _S_un_e__Union

  IN_PKTINFO {.bycopy.} = object
    ipi_addr: IN_ADDR
    ipi_ifindex: uint32

struct IN_ADDR
{
    _S_un_e__Union S_un;
}

struct IN_PKTINFO
{
    IN_ADDR ipi_addr;
    uint ipi_ifindex;
}