FindWindowExW

// USER32.dll  (Unicode / -W)
#include <windows.h>

HWND FindWindowExW(
    HWND hWndParent,   // optional
    HWND hWndChildAfter,   // optional
    LPCWSTR lpszClass,   // optional
    LPCWSTR lpszWindow   // optional
);

<DllImport("USER32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function FindWindowExW(
    hWndParent As IntPtr,   ' HWND optional
    hWndChildAfter As IntPtr,   ' HWND optional
    <MarshalAs(UnmanagedType.LPWStr)> lpszClass As String,   ' LPCWSTR optional
    <MarshalAs(UnmanagedType.LPWStr)> lpszWindow As String   ' LPCWSTR optional
) As IntPtr
End Function

' hWndParent : HWND optional
' hWndChildAfter : HWND optional
' lpszClass : LPCWSTR optional
' lpszWindow : LPCWSTR optional
Declare PtrSafe Function FindWindowExW Lib "user32" ( _
    ByVal hWndParent As LongPtr, _
    ByVal hWndChildAfter As LongPtr, _
    ByVal lpszClass As LongPtr, _
    ByVal lpszWindow As LongPtr) As LongPtr
' Unicode(W): 文字列は ByVal As LongPtr とし StrPtr(unicodeStr) を渡す
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

FindWindowExW = ctypes.windll.user32.FindWindowExW
FindWindowExW.restype = ctypes.c_void_p
FindWindowExW.argtypes = [
    wintypes.HANDLE,  # hWndParent : HWND optional
    wintypes.HANDLE,  # hWndChildAfter : HWND optional
    wintypes.LPCWSTR,  # lpszClass : LPCWSTR optional
    wintypes.LPCWSTR,  # lpszWindow : LPCWSTR optional
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
FindWindowExW = Fiddle::Function.new(
  lib['FindWindowExW'],
  [
    Fiddle::TYPE_VOIDP,  # hWndParent : HWND optional
    Fiddle::TYPE_VOIDP,  # hWndChildAfter : HWND optional
    Fiddle::TYPE_VOIDP,  # lpszClass : LPCWSTR optional
    Fiddle::TYPE_VOIDP,  # lpszWindow : LPCWSTR optional
  ],
  Fiddle::TYPE_VOIDP)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "user32")]
extern "system" {
    fn FindWindowExW(
        hWndParent: *mut core::ffi::c_void,  // HWND optional
        hWndChildAfter: *mut core::ffi::c_void,  // HWND optional
        lpszClass: *const u16,  // LPCWSTR optional
        lpszWindow: *const u16  // LPCWSTR optional
    ) -> *mut core::ffi::c_void;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern IntPtr FindWindowExW(IntPtr hWndParent, IntPtr hWndChildAfter, [MarshalAs(UnmanagedType.LPWStr)] string lpszClass, [MarshalAs(UnmanagedType.LPWStr)] string lpszWindow);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_FindWindowExW' -Namespace Win32 -PassThru
# $api::FindWindowExW(hWndParent, hWndChildAfter, lpszClass, lpszWindow)

#uselib "USER32.dll"
#func global FindWindowExW "FindWindowExW" wptr, wptr, wptr, wptr
; FindWindowExW hWndParent, hWndChildAfter, lpszClass, lpszWindow   ; 戻り値は stat
; hWndParent : HWND optional -> "wptr"
; hWndChildAfter : HWND optional -> "wptr"
; lpszClass : LPCWSTR optional -> "wptr"
; lpszWindow : LPCWSTR optional -> "wptr"
; ※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 FindWindowExW "FindWindowExW" sptr, sptr, wstr, wstr
; res = FindWindowExW(hWndParent, hWndChildAfter, lpszClass, lpszWindow)
; hWndParent : HWND optional -> "sptr"
; hWndChildAfter : HWND optional -> "sptr"
; lpszClass : LPCWSTR optional -> "wstr"
; lpszWindow : LPCWSTR optional -> "wstr"

; HWND FindWindowExW(HWND hWndParent, HWND hWndChildAfter, LPCWSTR lpszClass, LPCWSTR lpszWindow)
#uselib "USER32.dll"
#cfunc global FindWindowExW "FindWindowExW" intptr, intptr, wstr, wstr
; res = FindWindowExW(hWndParent, hWndChildAfter, lpszClass, lpszWindow)
; hWndParent : HWND optional -> "intptr"
; hWndChildAfter : HWND optional -> "intptr"
; lpszClass : LPCWSTR optional -> "wstr"
; lpszWindow : LPCWSTR optional -> "wstr"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procFindWindowExW = user32.NewProc("FindWindowExW")
)

// hWndParent (HWND optional), hWndChildAfter (HWND optional), lpszClass (LPCWSTR optional), lpszWindow (LPCWSTR optional)
r1, _, err := procFindWindowExW.Call(
	uintptr(hWndParent),
	uintptr(hWndChildAfter),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszClass))),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszWindow))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HWND

function FindWindowExW(
  hWndParent: THandle;   // HWND optional
  hWndChildAfter: THandle;   // HWND optional
  lpszClass: PWideChar;   // LPCWSTR optional
  lpszWindow: PWideChar   // LPCWSTR optional
): THandle; stdcall;
  external 'USER32.dll' name 'FindWindowExW';

result := DllCall("USER32\FindWindowExW"
    , "Ptr", hWndParent   ; HWND optional
    , "Ptr", hWndChildAfter   ; HWND optional
    , "WStr", lpszClass   ; LPCWSTR optional
    , "WStr", lpszWindow   ; LPCWSTR optional
    , "Ptr")   ; return: HWND

●FindWindowExW(hWndParent, hWndChildAfter, lpszClass, lpszWindow) = DLL("USER32.dll", "void* FindWindowExW(void*, void*, char*, char*)")
# 呼び出し: FindWindowExW(hWndParent, hWndChildAfter, lpszClass, lpszWindow)
# hWndParent : HWND optional -> "void*"
# hWndChildAfter : HWND optional -> "void*"
# lpszClass : LPCWSTR optional -> "char*"
# lpszWindow : LPCWSTR optional -> "char*"
# 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)。
# ※-W(Unicode)関数。なでしこ1はANSIのため -A 版の利用を推奨。