FindWindowW

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

HWND FindWindowW(
    LPCWSTR lpClassName,   // optional
    LPCWSTR lpWindowName   // optional
);

<DllImport("USER32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function FindWindowW(
    <MarshalAs(UnmanagedType.LPWStr)> lpClassName As String,   ' LPCWSTR optional
    <MarshalAs(UnmanagedType.LPWStr)> lpWindowName As String   ' LPCWSTR optional
) As IntPtr
End Function

' lpClassName : LPCWSTR optional
' lpWindowName : LPCWSTR optional
Declare PtrSafe Function FindWindowW Lib "user32" ( _
    ByVal lpClassName As LongPtr, _
    ByVal lpWindowName 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

FindWindowW = ctypes.windll.user32.FindWindowW
FindWindowW.restype = ctypes.c_void_p
FindWindowW.argtypes = [
    wintypes.LPCWSTR,  # lpClassName : LPCWSTR optional
    wintypes.LPCWSTR,  # lpWindowName : LPCWSTR optional
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
FindWindowW = Fiddle::Function.new(
  lib['FindWindowW'],
  [
    Fiddle::TYPE_VOIDP,  # lpClassName : LPCWSTR optional
    Fiddle::TYPE_VOIDP,  # lpWindowName : LPCWSTR optional
  ],
  Fiddle::TYPE_VOIDP)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "user32")]
extern "system" {
    fn FindWindowW(
        lpClassName: *const u16,  // LPCWSTR optional
        lpWindowName: *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 FindWindowW([MarshalAs(UnmanagedType.LPWStr)] string lpClassName, [MarshalAs(UnmanagedType.LPWStr)] string lpWindowName);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_FindWindowW' -Namespace Win32 -PassThru
# $api::FindWindowW(lpClassName, lpWindowName)

#uselib "USER32.dll"
#func global FindWindowW "FindWindowW" wptr, wptr
; FindWindowW lpClassName, lpWindowName   ; 戻り値は stat
; lpClassName : LPCWSTR optional -> "wptr"
; lpWindowName : 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 FindWindowW "FindWindowW" wstr, wstr
; res = FindWindowW(lpClassName, lpWindowName)
; lpClassName : LPCWSTR optional -> "wstr"
; lpWindowName : LPCWSTR optional -> "wstr"

; HWND FindWindowW(LPCWSTR lpClassName, LPCWSTR lpWindowName)
#uselib "USER32.dll"
#cfunc global FindWindowW "FindWindowW" wstr, wstr
; res = FindWindowW(lpClassName, lpWindowName)
; lpClassName : LPCWSTR optional -> "wstr"
; lpWindowName : LPCWSTR optional -> "wstr"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procFindWindowW = user32.NewProc("FindWindowW")
)

// lpClassName (LPCWSTR optional), lpWindowName (LPCWSTR optional)
r1, _, err := procFindWindowW.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpClassName))),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpWindowName))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HWND

function FindWindowW(
  lpClassName: PWideChar;   // LPCWSTR optional
  lpWindowName: PWideChar   // LPCWSTR optional
): THandle; stdcall;
  external 'USER32.dll' name 'FindWindowW';

result := DllCall("USER32\FindWindowW"
    , "WStr", lpClassName   ; LPCWSTR optional
    , "WStr", lpWindowName   ; LPCWSTR optional
    , "Ptr")   ; return: HWND

●FindWindowW(lpClassName, lpWindowName) = DLL("USER32.dll", "void* FindWindowW(char*, char*)")
# 呼び出し: FindWindowW(lpClassName, lpWindowName)
# lpClassName : LPCWSTR optional -> "char*"
# lpWindowName : 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。