UnregisterClassW

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

BOOL UnregisterClassW(
    LPCWSTR lpClassName,
    HINSTANCE hInstance   // optional
);

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

' lpClassName : LPCWSTR
' hInstance : HINSTANCE optional
Declare PtrSafe Function UnregisterClassW Lib "user32" ( _
    ByVal lpClassName As LongPtr, _
    ByVal hInstance 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

UnregisterClassW = ctypes.windll.user32.UnregisterClassW
UnregisterClassW.restype = wintypes.BOOL
UnregisterClassW.argtypes = [
    wintypes.LPCWSTR,  # lpClassName : LPCWSTR
    wintypes.HANDLE,  # hInstance : HINSTANCE optional
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

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

#[link(name = "user32")]
extern "system" {
    fn UnregisterClassW(
        lpClassName: *const u16,  // LPCWSTR
        hInstance: *mut core::ffi::c_void  // HINSTANCE optional
    ) -> 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 UnregisterClassW([MarshalAs(UnmanagedType.LPWStr)] string lpClassName, IntPtr hInstance);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_UnregisterClassW' -Namespace Win32 -PassThru
# $api::UnregisterClassW(lpClassName, hInstance)

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

; BOOL UnregisterClassW(LPCWSTR lpClassName, HINSTANCE hInstance)
#uselib "USER32.dll"
#cfunc global UnregisterClassW "UnregisterClassW" wstr, intptr
; res = UnregisterClassW(lpClassName, hInstance)
; lpClassName : LPCWSTR -> "wstr"
; hInstance : HINSTANCE optional -> "intptr"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procUnregisterClassW = user32.NewProc("UnregisterClassW")
)

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

function UnregisterClassW(
  lpClassName: PWideChar;   // LPCWSTR
  hInstance: THandle   // HINSTANCE optional
): BOOL; stdcall;
  external 'USER32.dll' name 'UnregisterClassW';

result := DllCall("USER32\UnregisterClassW"
    , "WStr", lpClassName   ; LPCWSTR
    , "Ptr", hInstance   ; HINSTANCE optional
    , "Int")   ; return: BOOL

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