CreateMDIWindowA

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

HWND CreateMDIWindowA(
    LPCSTR lpClassName,
    LPCSTR lpWindowName,
    WINDOW_STYLE dwStyle,
    INT X,
    INT Y,
    INT nWidth,
    INT nHeight,
    HWND hWndParent,   // optional
    HINSTANCE hInstance,   // optional
    LPARAM lParam
);

<DllImport("USER32.dll", CharSet:=CharSet.Ansi, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function CreateMDIWindowA(
    <MarshalAs(UnmanagedType.LPStr)> lpClassName As String,   ' LPCSTR
    <MarshalAs(UnmanagedType.LPStr)> lpWindowName As String,   ' LPCSTR
    dwStyle As UInteger,   ' WINDOW_STYLE
    X As Integer,   ' INT
    Y As Integer,   ' INT
    nWidth As Integer,   ' INT
    nHeight As Integer,   ' INT
    hWndParent As IntPtr,   ' HWND optional
    hInstance As IntPtr,   ' HINSTANCE optional
    lParam As IntPtr   ' LPARAM
) As IntPtr
End Function

' lpClassName : LPCSTR
' lpWindowName : LPCSTR
' dwStyle : WINDOW_STYLE
' X : INT
' Y : INT
' nWidth : INT
' nHeight : INT
' hWndParent : HWND optional
' hInstance : HINSTANCE optional
' lParam : LPARAM
Declare PtrSafe Function CreateMDIWindowA Lib "user32" ( _
    ByVal lpClassName As String, _
    ByVal lpWindowName As String, _
    ByVal dwStyle As Long, _
    ByVal X As Long, _
    ByVal Y As Long, _
    ByVal nWidth As Long, _
    ByVal nHeight As Long, _
    ByVal hWndParent As LongPtr, _
    ByVal hInstance As LongPtr, _
    ByVal lParam As LongPtr) As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

CreateMDIWindowA = ctypes.windll.user32.CreateMDIWindowA
CreateMDIWindowA.restype = ctypes.c_void_p
CreateMDIWindowA.argtypes = [
    wintypes.LPCSTR,  # lpClassName : LPCSTR
    wintypes.LPCSTR,  # lpWindowName : LPCSTR
    wintypes.DWORD,  # dwStyle : WINDOW_STYLE
    ctypes.c_int,  # X : INT
    ctypes.c_int,  # Y : INT
    ctypes.c_int,  # nWidth : INT
    ctypes.c_int,  # nHeight : INT
    wintypes.HANDLE,  # hWndParent : HWND optional
    wintypes.HANDLE,  # hInstance : HINSTANCE optional
    ctypes.c_ssize_t,  # lParam : LPARAM
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
CreateMDIWindowA = Fiddle::Function.new(
  lib['CreateMDIWindowA'],
  [
    Fiddle::TYPE_VOIDP,  # lpClassName : LPCSTR
    Fiddle::TYPE_VOIDP,  # lpWindowName : LPCSTR
    -Fiddle::TYPE_INT,  # dwStyle : WINDOW_STYLE
    Fiddle::TYPE_INT,  # X : INT
    Fiddle::TYPE_INT,  # Y : INT
    Fiddle::TYPE_INT,  # nWidth : INT
    Fiddle::TYPE_INT,  # nHeight : INT
    Fiddle::TYPE_VOIDP,  # hWndParent : HWND optional
    Fiddle::TYPE_VOIDP,  # hInstance : HINSTANCE optional
    Fiddle::TYPE_INTPTR_T,  # lParam : LPARAM
  ],
  Fiddle::TYPE_VOIDP)

#[link(name = "user32")]
extern "system" {
    fn CreateMDIWindowA(
        lpClassName: *const u8,  // LPCSTR
        lpWindowName: *const u8,  // LPCSTR
        dwStyle: u32,  // WINDOW_STYLE
        X: i32,  // INT
        Y: i32,  // INT
        nWidth: i32,  // INT
        nHeight: i32,  // INT
        hWndParent: *mut core::ffi::c_void,  // HWND optional
        hInstance: *mut core::ffi::c_void,  // HINSTANCE optional
        lParam: isize  // LPARAM
    ) -> *mut core::ffi::c_void;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Ansi, SetLastError = true)]
public static extern IntPtr CreateMDIWindowA([MarshalAs(UnmanagedType.LPStr)] string lpClassName, [MarshalAs(UnmanagedType.LPStr)] string lpWindowName, uint dwStyle, int X, int Y, int nWidth, int nHeight, IntPtr hWndParent, IntPtr hInstance, IntPtr lParam);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_CreateMDIWindowA' -Namespace Win32 -PassThru
# $api::CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)

#uselib "USER32.dll"
#func global CreateMDIWindowA "CreateMDIWindowA" sptr, sptr, sptr, sptr, sptr, sptr, sptr, sptr, sptr, sptr
; CreateMDIWindowA lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam   ; 戻り値は stat
; lpClassName : LPCSTR -> "sptr"
; lpWindowName : LPCSTR -> "sptr"
; dwStyle : WINDOW_STYLE -> "sptr"
; X : INT -> "sptr"
; Y : INT -> "sptr"
; nWidth : INT -> "sptr"
; nHeight : INT -> "sptr"
; hWndParent : HWND optional -> "sptr"
; hInstance : HINSTANCE optional -> "sptr"
; lParam : LPARAM -> "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 CreateMDIWindowA "CreateMDIWindowA" str, str, int, int, int, int, int, sptr, sptr, sptr
; res = CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)
; lpClassName : LPCSTR -> "str"
; lpWindowName : LPCSTR -> "str"
; dwStyle : WINDOW_STYLE -> "int"
; X : INT -> "int"
; Y : INT -> "int"
; nWidth : INT -> "int"
; nHeight : INT -> "int"
; hWndParent : HWND optional -> "sptr"
; hInstance : HINSTANCE optional -> "sptr"
; lParam : LPARAM -> "sptr"

; HWND CreateMDIWindowA(LPCSTR lpClassName, LPCSTR lpWindowName, WINDOW_STYLE dwStyle, INT X, INT Y, INT nWidth, INT nHeight, HWND hWndParent, HINSTANCE hInstance, LPARAM lParam)
#uselib "USER32.dll"
#cfunc global CreateMDIWindowA "CreateMDIWindowA" str, str, int, int, int, int, int, intptr, intptr, intptr
; res = CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)
; lpClassName : LPCSTR -> "str"
; lpWindowName : LPCSTR -> "str"
; dwStyle : WINDOW_STYLE -> "int"
; X : INT -> "int"
; Y : INT -> "int"
; nWidth : INT -> "int"
; nHeight : INT -> "int"
; hWndParent : HWND optional -> "intptr"
; hInstance : HINSTANCE optional -> "intptr"
; lParam : LPARAM -> "intptr"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procCreateMDIWindowA = user32.NewProc("CreateMDIWindowA")
)

// lpClassName (LPCSTR), lpWindowName (LPCSTR), dwStyle (WINDOW_STYLE), X (INT), Y (INT), nWidth (INT), nHeight (INT), hWndParent (HWND optional), hInstance (HINSTANCE optional), lParam (LPARAM)
r1, _, err := procCreateMDIWindowA.Call(
	uintptr(unsafe.Pointer(windows.BytePtrFromString(lpClassName))),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(lpWindowName))),
	uintptr(dwStyle),
	uintptr(X),
	uintptr(Y),
	uintptr(nWidth),
	uintptr(nHeight),
	uintptr(hWndParent),
	uintptr(hInstance),
	uintptr(lParam),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HWND

function CreateMDIWindowA(
  lpClassName: PAnsiChar;   // LPCSTR
  lpWindowName: PAnsiChar;   // LPCSTR
  dwStyle: DWORD;   // WINDOW_STYLE
  X: Integer;   // INT
  Y: Integer;   // INT
  nWidth: Integer;   // INT
  nHeight: Integer;   // INT
  hWndParent: THandle;   // HWND optional
  hInstance: THandle;   // HINSTANCE optional
  lParam: NativeInt   // LPARAM
): THandle; stdcall;
  external 'USER32.dll' name 'CreateMDIWindowA';

result := DllCall("USER32\CreateMDIWindowA"
    , "AStr", lpClassName   ; LPCSTR
    , "AStr", lpWindowName   ; LPCSTR
    , "UInt", dwStyle   ; WINDOW_STYLE
    , "Int", X   ; INT
    , "Int", Y   ; INT
    , "Int", nWidth   ; INT
    , "Int", nHeight   ; INT
    , "Ptr", hWndParent   ; HWND optional
    , "Ptr", hInstance   ; HINSTANCE optional
    , "Ptr", lParam   ; LPARAM
    , "Ptr")   ; return: HWND

●CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam) = DLL("USER32.dll", "void* CreateMDIWindowA(char*, char*, dword, int, int, int, int, void*, void*, int)")
# 呼び出し: CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)
# lpClassName : LPCSTR -> "char*"
# lpWindowName : LPCSTR -> "char*"
# dwStyle : WINDOW_STYLE -> "dword"
# X : INT -> "int"
# Y : INT -> "int"
# nWidth : INT -> "int"
# nHeight : INT -> "int"
# hWndParent : HWND optional -> "void*"
# hInstance : HINSTANCE optional -> "void*"
# lParam : LPARAM -> "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)。

const std = @import("std");

extern "user32" fn CreateMDIWindowA(
    lpClassName: [*c]const u8, // LPCSTR
    lpWindowName: [*c]const u8, // LPCSTR
    dwStyle: u32, // WINDOW_STYLE
    X: i32, // INT
    Y: i32, // INT
    nWidth: i32, // INT
    nHeight: i32, // INT
    hWndParent: ?*anyopaque, // HWND optional
    hInstance: ?*anyopaque, // HINSTANCE optional
    lParam: isize // LPARAM
) callconv(std.os.windows.WINAPI) ?*anyopaque;

proc CreateMDIWindowA(
    lpClassName: cstring,  # LPCSTR
    lpWindowName: cstring,  # LPCSTR
    dwStyle: uint32,  # WINDOW_STYLE
    X: int32,  # INT
    Y: int32,  # INT
    nWidth: int32,  # INT
    nHeight: int32,  # INT
    hWndParent: pointer,  # HWND optional
    hInstance: pointer,  # HINSTANCE optional
    lParam: int  # LPARAM
): pointer {.importc: "CreateMDIWindowA", stdcall, dynlib: "USER32.dll".}

pragma(lib, "user32");
extern(Windows)
void* CreateMDIWindowA(
    const(char)* lpClassName,   // LPCSTR
    const(char)* lpWindowName,   // LPCSTR
    uint dwStyle,   // WINDOW_STYLE
    int X,   // INT
    int Y,   // INT
    int nWidth,   // INT
    int nHeight,   // INT
    void* hWndParent,   // HWND optional
    void* hInstance,   // HINSTANCE optional
    ptrdiff_t lParam   // LPARAM
);

ccall((:CreateMDIWindowA, "USER32.dll"), stdcall, Ptr{Cvoid},
      (Cstring, Cstring, UInt32, Int32, Int32, Int32, Int32, Ptr{Cvoid}, Ptr{Cvoid}, Int),
      lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)
# lpClassName : LPCSTR -> Cstring
# lpWindowName : LPCSTR -> Cstring
# dwStyle : WINDOW_STYLE -> UInt32
# X : INT -> Int32
# Y : INT -> Int32
# nWidth : INT -> Int32
# nHeight : INT -> Int32
# hWndParent : HWND optional -> Ptr{Cvoid}
# hInstance : HINSTANCE optional -> Ptr{Cvoid}
# lParam : LPARAM -> Int
# stdcall は 32bit のみ意味を持つ(x64 では無視)。

local ffi = require("ffi")
ffi.cdef[[
void* CreateMDIWindowA(
    const char* lpClassName,
    const char* lpWindowName,
    uint32_t dwStyle,
    int32_t X,
    int32_t Y,
    int32_t nWidth,
    int32_t nHeight,
    void* hWndParent,
    void* hInstance,
    intptr_t lParam);
]]
local user32 = ffi.load("user32")
-- user32.CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)
-- lpClassName : LPCSTR
-- lpWindowName : LPCSTR
-- dwStyle : WINDOW_STYLE
-- X : INT
-- Y : INT
-- nWidth : INT
-- nHeight : INT
-- hWndParent : HWND optional
-- hInstance : HINSTANCE optional
-- lParam : LPARAM
-- 構造体/GUIDへのポインタは cdef が通るよう void* で表記(実型は各引数コメント参照)。値渡し構造体・enum は対応する typedef を cdef に追加すること。

const koffi = require('koffi');
const lib = koffi.load('USER32.dll');
const CreateMDIWindowA = lib.func('__stdcall', 'CreateMDIWindowA', 'void *', ['str', 'str', 'uint32_t', 'int32_t', 'int32_t', 'int32_t', 'int32_t', 'void *', 'void *', 'intptr_t']);
// CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)
// lpClassName : LPCSTR -> 'str'
// lpWindowName : LPCSTR -> 'str'
// dwStyle : WINDOW_STYLE -> 'uint32_t'
// X : INT -> 'int32_t'
// Y : INT -> 'int32_t'
// nWidth : INT -> 'int32_t'
// nHeight : INT -> 'int32_t'
// hWndParent : HWND optional -> 'void *'
// hInstance : HINSTANCE optional -> 'void *'
// lParam : LPARAM -> 'intptr_t'
// 出力ポインタは koffi.out(...) で包む。構造体は koffi.struct で定義。

const lib = Deno.dlopen("USER32.dll", {
  CreateMDIWindowA: { parameters: ["buffer", "buffer", "u32", "i32", "i32", "i32", "i32", "pointer", "pointer", "isize"], result: "pointer" },
});
// lib.symbols.CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam)
// lpClassName : LPCSTR -> "buffer"
// lpWindowName : LPCSTR -> "buffer"
// dwStyle : WINDOW_STYLE -> "u32"
// X : INT -> "i32"
// Y : INT -> "i32"
// nWidth : INT -> "i32"
// nHeight : INT -> "i32"
// hWndParent : HWND optional -> "pointer"
// hInstance : HINSTANCE optional -> "pointer"
// lParam : LPARAM -> "isize"
// 文字列は "buffer"。ANSI(-A) は new TextEncoder() で UTF-8/ANSI バイト列(末尾に \x00)を渡す。
// 値渡し構造体は { struct: [ ...field types... ] } を使用。

<?php
$ffi = FFI::cdef(<<<C
void* CreateMDIWindowA(
    const char* lpClassName,
    const char* lpWindowName,
    uint32_t dwStyle,
    int32_t X,
    int32_t Y,
    int32_t nWidth,
    int32_t nHeight,
    void* hWndParent,
    void* hInstance,
    intptr_t lParam);
C, "USER32.dll");
// $ffi->CreateMDIWindowA(lpClassName, lpWindowName, dwStyle, X, Y, nWidth, nHeight, hWndParent, hInstance, lParam);
// lpClassName : LPCSTR
// lpWindowName : LPCSTR
// dwStyle : WINDOW_STYLE
// X : INT
// Y : INT
// nWidth : INT
// nHeight : INT
// hWndParent : HWND optional
// hInstance : HINSTANCE optional
// lParam : LPARAM
// 構造体/GUIDへのポインタは cdef が通るよう void* で表記(実型は各引数コメント参照)。値渡し構造体・enum は対応する typedef を cdef に追加すること。
// WINAPI(stdcall): x64 では呼出規約が統一されるため問題なし。x86 では __stdcall 対応のラッパが必要な場合あり。

import com.sun.jna.*;
import com.sun.jna.ptr.*;
import com.sun.jna.win32.StdCallLibrary;
import com.sun.jna.win32.W32APIOptions;

public interface User32 extends StdCallLibrary {
    User32 INSTANCE = Native.load("user32", User32.class, W32APIOptions.ASCII_OPTIONS);
    Pointer CreateMDIWindowA(
        String lpClassName,   // LPCSTR
        String lpWindowName,   // LPCSTR
        int dwStyle,   // WINDOW_STYLE
        int X,   // INT
        int Y,   // INT
        int nWidth,   // INT
        int nHeight,   // INT
        Pointer hWndParent,   // HWND optional
        Pointer hInstance,   // HINSTANCE optional
        long lParam   // LPARAM
    );
}

@[Link("user32")]
lib LibUSER32
  fun CreateMDIWindowA = CreateMDIWindowA(
    lpClassName : UInt8*,   # LPCSTR
    lpWindowName : UInt8*,   # LPCSTR
    dwStyle : UInt32,   # WINDOW_STYLE
    X : Int32,   # INT
    Y : Int32,   # INT
    nWidth : Int32,   # INT
    nHeight : Int32,   # INT
    hWndParent : Void*,   # HWND optional
    hInstance : Void*,   # HINSTANCE optional
    lParam : LibC::SSizeT   # LPARAM
  ) : Void*
end
# 構造体/GUID/enum は lib 内に対応する型定義が必要。
# 呼出規約: x64 は規約統一のため OK。x86(32bit)は WINAPI=stdcall だが Crystal の fun に stdcall 付与構文がなく非対応。

import 'dart:ffi';
import 'package:ffi/ffi.dart';

typedef CreateMDIWindowANative = Pointer<Void> Function(Pointer<Utf8>, Pointer<Utf8>, Uint32, Int32, Int32, Int32, Int32, Pointer<Void>, Pointer<Void>, IntPtr);
typedef CreateMDIWindowADart = Pointer<Void> Function(Pointer<Utf8>, Pointer<Utf8>, int, int, int, int, int, Pointer<Void>, Pointer<Void>, int);
final CreateMDIWindowA = DynamicLibrary.open('USER32.dll')
    .lookupFunction<CreateMDIWindowANative, CreateMDIWindowADart>('CreateMDIWindowA');
// lpClassName : LPCSTR -> Pointer<Utf8>
// lpWindowName : LPCSTR -> Pointer<Utf8>
// dwStyle : WINDOW_STYLE -> Uint32
// X : INT -> Int32
// Y : INT -> Int32
// nWidth : INT -> Int32
// nHeight : INT -> Int32
// hWndParent : HWND optional -> Pointer<Void>
// hInstance : HINSTANCE optional -> Pointer<Void>
// lParam : LPARAM -> IntPtr
// 文字列は package:ffi の "...".toNativeUtf16()/toNativeUtf8() で変換。

{$mode objfpc}{$H+}
function CreateMDIWindowA(
  lpClassName: PAnsiChar;   // LPCSTR
  lpWindowName: PAnsiChar;   // LPCSTR
  dwStyle: DWORD;   // WINDOW_STYLE
  X: Integer;   // INT
  Y: Integer;   // INT
  nWidth: Integer;   // INT
  nHeight: Integer;   // INT
  hWndParent: THandle;   // HWND optional
  hInstance: THandle;   // HINSTANCE optional
  lParam: NativeInt   // LPARAM
): THandle; stdcall;
  external 'USER32.dll' name 'CreateMDIWindowA';

import Foreign
import Foreign.C.Types
import Foreign.C.String

foreign import stdcall safe "CreateMDIWindowA"
  c_CreateMDIWindowA :: CString -> CString -> Word32 -> Int32 -> Int32 -> Int32 -> Int32 -> Ptr () -> Ptr () -> CIntPtr -> IO (Ptr ())
-- lpClassName : LPCSTR -> CString
-- lpWindowName : LPCSTR -> CString
-- dwStyle : WINDOW_STYLE -> Word32
-- X : INT -> Int32
-- Y : INT -> Int32
-- nWidth : INT -> Int32
-- nHeight : INT -> Int32
-- hWndParent : HWND optional -> Ptr ()
-- hInstance : HINSTANCE optional -> Ptr ()
-- lParam : LPARAM -> CIntPtr
-- 要 GHC(Windows)。stdcall は x64 では ccall として扱われる。ブロックする API は safe 呼び出し推奨。

open Ctypes
open Foreign

let createmdiwindowa =
  foreign "CreateMDIWindowA"
    (string @-> string @-> uint32_t @-> int32_t @-> int32_t @-> int32_t @-> int32_t @-> (ptr void) @-> (ptr void) @-> intptr_t @-> returning (ptr void))
(* lpClassName : LPCSTR -> string *)
(* lpWindowName : LPCSTR -> string *)
(* dwStyle : WINDOW_STYLE -> uint32_t *)
(* X : INT -> int32_t *)
(* Y : INT -> int32_t *)
(* nWidth : INT -> int32_t *)
(* nHeight : INT -> int32_t *)
(* hWndParent : HWND optional -> (ptr void) *)
(* hInstance : HINSTANCE optional -> (ptr void) *)
(* lParam : LPARAM -> intptr_t *)
(* foreign は cdecl 前提。x64 Windows では WINAPI と一致。構造体は ctypes structure を定義のこと。 *)

(cffi:define-foreign-library user32 (t "USER32.dll"))
(cffi:use-foreign-library user32)

(cffi:defcfun ("CreateMDIWindowA" create-mdiwindow-a :convention :stdcall) :pointer
  (lp-class-name :string)   ; LPCSTR
  (lp-window-name :string)   ; LPCSTR
  (dw-style :uint32)   ; WINDOW_STYLE
  (x :int32)   ; INT
  (y :int32)   ; INT
  (n-width :int32)   ; INT
  (n-height :int32)   ; INT
  (h-wnd-parent :pointer)   ; HWND optional
  (h-instance :pointer)   ; HINSTANCE optional
  (l-param :int64))   ; LPARAM
; isize/usize(INT_PTR/SIZE_T)は x64 前提で :int64/:uint64。x86 では :int32/:uint32。

use Win32::API;
my $CreateMDIWindowA = Win32::API::More->new('USER32',
    'HANDLE CreateMDIWindowA(LPCSTR lpClassName, LPCSTR lpWindowName, DWORD dwStyle, int X, int Y, int nWidth, int nHeight, HANDLE hWndParent, HANDLE hInstance, LPARAM lParam)');
# my $ret = $CreateMDIWindowA->Call($lpClassName, $lpWindowName, $dwStyle, $X, $Y, $nWidth, $nHeight, $hWndParent, $hInstance, $lParam);
# lpClassName : LPCSTR -> LPCSTR
# lpWindowName : LPCSTR -> LPCSTR
# dwStyle : WINDOW_STYLE -> DWORD
# X : INT -> int
# Y : INT -> int
# nWidth : INT -> int
# nHeight : INT -> int
# hWndParent : HWND optional -> HANDLE
# hInstance : HINSTANCE optional -> HANDLE
# lParam : LPARAM -> LPARAM
# 値渡し構造体は pack() した文字列、または Win32::API::Struct を使用。