UnregisterClassA

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

BOOL UnregisterClassA(
    LPCSTR lpClassName,
    HINSTANCE hInstance   // optional
);

<DllImport("USER32.dll", CharSet:=CharSet.Ansi, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function UnregisterClassA(
    <MarshalAs(UnmanagedType.LPStr)> lpClassName As String,   ' LPCSTR
    hInstance As IntPtr   ' HINSTANCE optional
) As Boolean
End Function

' lpClassName : LPCSTR
' hInstance : HINSTANCE optional
Declare PtrSafe Function UnregisterClassA Lib "user32" ( _
    ByVal lpClassName As String, _
    ByVal hInstance As LongPtr) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

UnregisterClassA = ctypes.windll.user32.UnregisterClassA
UnregisterClassA.restype = wintypes.BOOL
UnregisterClassA.argtypes = [
    wintypes.LPCSTR,  # lpClassName : LPCSTR
    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')
UnregisterClassA = Fiddle::Function.new(
  lib['UnregisterClassA'],
  [
    Fiddle::TYPE_VOIDP,  # lpClassName : LPCSTR
    Fiddle::TYPE_VOIDP,  # hInstance : HINSTANCE optional
  ],
  Fiddle::TYPE_INT)

#[link(name = "user32")]
extern "system" {
    fn UnregisterClassA(
        lpClassName: *const u8,  // LPCSTR
        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.Ansi, SetLastError = true)]
public static extern bool UnregisterClassA([MarshalAs(UnmanagedType.LPStr)] string lpClassName, IntPtr hInstance);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_UnregisterClassA' -Namespace Win32 -PassThru
# $api::UnregisterClassA(lpClassName, hInstance)

#uselib "USER32.dll"
#func global UnregisterClassA "UnregisterClassA" sptr, sptr
; UnregisterClassA lpClassName, hInstance   ; 戻り値は stat
; lpClassName : LPCSTR -> "sptr"
; hInstance : HINSTANCE optional -> "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 UnregisterClassA "UnregisterClassA" str, sptr
; res = UnregisterClassA(lpClassName, hInstance)
; lpClassName : LPCSTR -> "str"
; hInstance : HINSTANCE optional -> "sptr"

; BOOL UnregisterClassA(LPCSTR lpClassName, HINSTANCE hInstance)
#uselib "USER32.dll"
#cfunc global UnregisterClassA "UnregisterClassA" str, intptr
; res = UnregisterClassA(lpClassName, hInstance)
; lpClassName : LPCSTR -> "str"
; hInstance : HINSTANCE optional -> "intptr"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procUnregisterClassA = user32.NewProc("UnregisterClassA")
)

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

function UnregisterClassA(
  lpClassName: PAnsiChar;   // LPCSTR
  hInstance: THandle   // HINSTANCE optional
): BOOL; stdcall;
  external 'USER32.dll' name 'UnregisterClassA';

result := DllCall("USER32\UnregisterClassA"
    , "AStr", lpClassName   ; LPCSTR
    , "Ptr", hInstance   ; HINSTANCE optional
    , "Int")   ; return: BOOL

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