GetClassInfoExW

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

BOOL GetClassInfoExW(
    HINSTANCE hInstance,   // optional
    LPCWSTR lpszClass,
    WNDCLASSEXW* lpwcx
);

<DllImport("USER32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetClassInfoExW(
    hInstance As IntPtr,   ' HINSTANCE optional
    <MarshalAs(UnmanagedType.LPWStr)> lpszClass As String,   ' LPCWSTR
    lpwcx As IntPtr   ' WNDCLASSEXW* out
) As Boolean
End Function

' hInstance : HINSTANCE optional
' lpszClass : LPCWSTR
' lpwcx : WNDCLASSEXW* out
Declare PtrSafe Function GetClassInfoExW Lib "user32" ( _
    ByVal hInstance As LongPtr, _
    ByVal lpszClass As LongPtr, _
    ByVal lpwcx As LongPtr) As Long
' 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

GetClassInfoExW = ctypes.windll.user32.GetClassInfoExW
GetClassInfoExW.restype = wintypes.BOOL
GetClassInfoExW.argtypes = [
    wintypes.HANDLE,  # hInstance : HINSTANCE optional
    wintypes.LPCWSTR,  # lpszClass : LPCWSTR
    ctypes.c_void_p,  # lpwcx : WNDCLASSEXW* out
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
GetClassInfoExW = Fiddle::Function.new(
  lib['GetClassInfoExW'],
  [
    Fiddle::TYPE_VOIDP,  # hInstance : HINSTANCE optional
    Fiddle::TYPE_VOIDP,  # lpszClass : LPCWSTR
    Fiddle::TYPE_VOIDP,  # lpwcx : WNDCLASSEXW* out
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "user32")]
extern "system" {
    fn GetClassInfoExW(
        hInstance: *mut core::ffi::c_void,  // HINSTANCE optional
        lpszClass: *const u16,  // LPCWSTR
        lpwcx: *mut WNDCLASSEXW  // WNDCLASSEXW* out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("USER32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern bool GetClassInfoExW(IntPtr hInstance, [MarshalAs(UnmanagedType.LPWStr)] string lpszClass, IntPtr lpwcx);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_GetClassInfoExW' -Namespace Win32 -PassThru
# $api::GetClassInfoExW(hInstance, lpszClass, lpwcx)

#uselib "USER32.dll"
#func global GetClassInfoExW "GetClassInfoExW" wptr, wptr, wptr
; GetClassInfoExW hInstance, lpszClass, varptr(lpwcx)   ; 戻り値は stat
; hInstance : HINSTANCE optional -> "wptr"
; lpszClass : LPCWSTR -> "wptr"
; lpwcx : WNDCLASSEXW* out -> "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 GetClassInfoExW "GetClassInfoExW" sptr, wstr, var
; res = GetClassInfoExW(hInstance, lpszClass, lpwcx)
; hInstance : HINSTANCE optional -> "sptr"
; lpszClass : LPCWSTR -> "wstr"
; lpwcx : WNDCLASSEXW* out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

; BOOL GetClassInfoExW(HINSTANCE hInstance, LPCWSTR lpszClass, WNDCLASSEXW* lpwcx)
#uselib "USER32.dll"
#cfunc global GetClassInfoExW "GetClassInfoExW" intptr, wstr, var
; res = GetClassInfoExW(hInstance, lpszClass, lpwcx)
; hInstance : HINSTANCE optional -> "intptr"
; lpszClass : LPCWSTR -> "wstr"
; lpwcx : WNDCLASSEXW* out -> "var"
; ※出力/バッファ引数は var 方式(変数を直接渡す)。varptr 方式にも切替可。

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procGetClassInfoExW = user32.NewProc("GetClassInfoExW")
)

// hInstance (HINSTANCE optional), lpszClass (LPCWSTR), lpwcx (WNDCLASSEXW* out)
r1, _, err := procGetClassInfoExW.Call(
	uintptr(hInstance),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszClass))),
	uintptr(lpwcx),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function GetClassInfoExW(
  hInstance: THandle;   // HINSTANCE optional
  lpszClass: PWideChar;   // LPCWSTR
  lpwcx: Pointer   // WNDCLASSEXW* out
): BOOL; stdcall;
  external 'USER32.dll' name 'GetClassInfoExW';

result := DllCall("USER32\GetClassInfoExW"
    , "Ptr", hInstance   ; HINSTANCE optional
    , "WStr", lpszClass   ; LPCWSTR
    , "Ptr", lpwcx   ; WNDCLASSEXW* out
    , "Int")   ; return: BOOL

●GetClassInfoExW(hInstance, lpszClass, lpwcx) = DLL("USER32.dll", "bool GetClassInfoExW(void*, char*, void*)")
# 呼び出し: GetClassInfoExW(hInstance, lpszClass, lpwcx)
# hInstance : HINSTANCE optional -> "void*"
# lpszClass : LPCWSTR -> "char*"
# lpwcx : WNDCLASSEXW* out -> "void*"
# 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。