NMUPDOWN

using System;
using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct NMHDR
{
    public IntPtr hwndFrom;
    public UIntPtr idFrom;
    public uint code;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct NMUPDOWN
{
    public NMHDR hdr;
    public int iPos;
    public int iDelta;
}

Imports System.Runtime.InteropServices

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
Public Structure NMHDR
    Public hwndFrom As IntPtr
    Public idFrom As UIntPtr
    Public code As UInteger
End Structure

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>
Public Structure NMUPDOWN
    Public hdr As NMHDR
    Public iPos As Integer
    Public iDelta As Integer
End Structure

import ctypes
from ctypes import wintypes

class NMHDR(ctypes.Structure):
    _fields_ = [
        ("hwndFrom", ctypes.c_void_p),
        ("idFrom", ctypes.c_size_t),
        ("code", wintypes.DWORD),
    ]

class NMUPDOWN(ctypes.Structure):
    _fields_ = [
        ("hdr", NMHDR),
        ("iPos", ctypes.c_int),
        ("iDelta", ctypes.c_int),
    ]

#[repr(C)]
pub struct NMHDR {
    pub hwndFrom: *mut core::ffi::c_void,
    pub idFrom: usize,
    pub code: u32,
}

#[repr(C)]
pub struct NMUPDOWN {
    pub hdr: NMHDR,
    pub iPos: i32,
    pub iDelta: i32,
}

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

type NMHDR struct {
	hwndFrom uintptr
	idFrom uintptr
	code uint32
}

type NMUPDOWN struct {
	hdr NMHDR
	iPos int32
	iDelta int32
}

type
  NMHDR = record
    hwndFrom: Pointer;
    idFrom: NativeUInt;
    code: DWORD;
  end;

  NMUPDOWN = record
    hdr: NMHDR;
    iPos: Integer;
    iDelta: Integer;
  end;

const NMHDR = extern struct {
    hwndFrom: ?*anyopaque,
    idFrom: usize,
    code: u32,
};

const NMUPDOWN = extern struct {
    hdr: NMHDR,
    iPos: i32,
    iDelta: i32,
};

type
  NMHDR {.bycopy.} = object
    hwndFrom: pointer
    idFrom: uint
    code: uint32

  NMUPDOWN {.bycopy.} = object
    hdr: NMHDR
    iPos: int32
    iDelta: int32

struct NMHDR
{
    void* hwndFrom;
    size_t idFrom;
    uint code;
}

struct NMUPDOWN
{
    NMHDR hdr;
    int iPos;
    int iDelta;
}