GetWindowLongA

// USER32.dll  (ANSI / -A)
#include <windows.h>

INT GetWindowLongA(
    HWND hWnd,
    WINDOW_LONG_PTR_INDEX nIndex
);

<DllImport("USER32.dll", CharSet:=CharSet.Ansi, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetWindowLongA(
    hWnd As IntPtr,   ' HWND
    nIndex As Integer   ' WINDOW_LONG_PTR_INDEX
) As Integer
End Function

' hWnd : HWND
' nIndex : WINDOW_LONG_PTR_INDEX
Declare PtrSafe Function GetWindowLongA Lib "user32" ( _
    ByVal hWnd As LongPtr, _
    ByVal nIndex As Long) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

GetWindowLongA = ctypes.windll.user32.GetWindowLongA
GetWindowLongA.restype = ctypes.c_int
GetWindowLongA.argtypes = [
    wintypes.HANDLE,  # hWnd : HWND
    ctypes.c_int,  # nIndex : WINDOW_LONG_PTR_INDEX
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
GetWindowLongA = Fiddle::Function.new(
  lib['GetWindowLongA'],
  [
    Fiddle::TYPE_VOIDP,  # hWnd : HWND
    Fiddle::TYPE_INT,  # nIndex : WINDOW_LONG_PTR_INDEX
  ],
  Fiddle::TYPE_INT)

#[link(name = "user32")]
extern "system" {
    fn GetWindowLongA(
        hWnd: *mut core::ffi::c_void,  // HWND
        nIndex: i32  // WINDOW_LONG_PTR_INDEX
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Ansi, SetLastError = true)]
public static extern int GetWindowLongA(IntPtr hWnd, int nIndex);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_GetWindowLongA' -Namespace Win32 -PassThru
# $api::GetWindowLongA(hWnd, nIndex)

#uselib "USER32.dll"
#func global GetWindowLongA "GetWindowLongA" sptr, sptr
; GetWindowLongA hWnd, nIndex   ; 戻り値は stat
; hWnd : HWND -> "sptr"
; nIndex : WINDOW_LONG_PTR_INDEX -> "sptr"
; ※HSP3.7は #func のため戻り値はシステム変数 stat に格納されます。

#uselib "USER32.dll"
#cfunc global GetWindowLongA "GetWindowLongA" sptr, int
; res = GetWindowLongA(hWnd, nIndex)
; hWnd : HWND -> "sptr"
; nIndex : WINDOW_LONG_PTR_INDEX -> "int"

; INT GetWindowLongA(HWND hWnd, WINDOW_LONG_PTR_INDEX nIndex)
#uselib "USER32.dll"
#cfunc global GetWindowLongA "GetWindowLongA" intptr, int
; res = GetWindowLongA(hWnd, nIndex)
; hWnd : HWND -> "intptr"
; nIndex : WINDOW_LONG_PTR_INDEX -> "int"

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procGetWindowLongA = user32.NewProc("GetWindowLongA")
)

// hWnd (HWND), nIndex (WINDOW_LONG_PTR_INDEX)
r1, _, err := procGetWindowLongA.Call(
	uintptr(hWnd),
	uintptr(nIndex),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function GetWindowLongA(
  hWnd: THandle;   // HWND
  nIndex: Integer   // WINDOW_LONG_PTR_INDEX
): Integer; stdcall;
  external 'USER32.dll' name 'GetWindowLongA';

result := DllCall("USER32\GetWindowLongA"
    , "Ptr", hWnd   ; HWND
    , "Int", nIndex   ; WINDOW_LONG_PTR_INDEX
    , "Int")   ; return: INT

●GetWindowLongA(hWnd, nIndex) = DLL("USER32.dll", "int GetWindowLongA(void*, int)")
# 呼び出し: GetWindowLongA(hWnd, nIndex)
# hWnd : HWND -> "void*"
# nIndex : WINDOW_LONG_PTR_INDEX -> "int"
# なでしこ1は32bit・ANSI(Shift_JIS)。文字列=char*(ANSI)、ポインタ/ハンドル=void*(4byte)。