GetActiveWindow

// USER32.dll
#include <windows.h>

HWND GetActiveWindow(void);

<DllImport("USER32.dll", ExactSpelling:=True)>
Public Shared Function GetActiveWindow() As IntPtr
End Function

Declare PtrSafe Function GetActiveWindow Lib "user32" () As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

GetActiveWindow = ctypes.windll.user32.GetActiveWindow
GetActiveWindow.restype = ctypes.c_void_p
GetActiveWindow.argtypes = []

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
GetActiveWindow = Fiddle::Function.new(
  lib['GetActiveWindow'],
  [],
  Fiddle::TYPE_VOIDP)

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

$sig = @"
[DllImport("USER32.dll")]
public static extern IntPtr GetActiveWindow();
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_GetActiveWindow' -Namespace Win32 -PassThru
# $api::GetActiveWindow()

#uselib "USER32.dll"
#func global GetActiveWindow "GetActiveWindow"
; GetActiveWindow   ; 戻り値は stat
; ※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 GetActiveWindow "GetActiveWindow"
; res = GetActiveWindow()

; HWND GetActiveWindow()
#uselib "USER32.dll"
#cfunc global GetActiveWindow "GetActiveWindow"
; res = GetActiveWindow()

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procGetActiveWindow = user32.NewProc("GetActiveWindow")
)

r1, _, err := procGetActiveWindow.Call()
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HWND

function GetActiveWindow: THandle; stdcall;
  external 'USER32.dll' name 'GetActiveWindow';

result := DllCall("USER32\GetActiveWindow", "Ptr")

●GetActiveWindow() = DLL("USER32.dll", "void* GetActiveWindow()")
# 呼び出し: GetActiveWindow()
# 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)。