GetCPInfoExW

// KERNEL32.dll  (Unicode / -W)
#include <windows.h>

BOOL GetCPInfoExW(
    DWORD CodePage,
    DWORD dwFlags,
    CPINFOEXW* lpCPInfoEx
);

<DllImport("KERNEL32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetCPInfoExW(
    CodePage As UInteger,   ' DWORD
    dwFlags As UInteger,   ' DWORD
    lpCPInfoEx As IntPtr   ' CPINFOEXW* out
) As Boolean
End Function

' CodePage : DWORD
' dwFlags : DWORD
' lpCPInfoEx : CPINFOEXW* out
Declare PtrSafe Function GetCPInfoExW Lib "kernel32" ( _
    ByVal CodePage As Long, _
    ByVal dwFlags As Long, _
    ByVal lpCPInfoEx 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

GetCPInfoExW = ctypes.windll.kernel32.GetCPInfoExW
GetCPInfoExW.restype = wintypes.BOOL
GetCPInfoExW.argtypes = [
    wintypes.DWORD,  # CodePage : DWORD
    wintypes.DWORD,  # dwFlags : DWORD
    ctypes.c_void_p,  # lpCPInfoEx : CPINFOEXW* out
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('KERNEL32.dll')
GetCPInfoExW = Fiddle::Function.new(
  lib['GetCPInfoExW'],
  [
    -Fiddle::TYPE_INT,  # CodePage : DWORD
    -Fiddle::TYPE_INT,  # dwFlags : DWORD
    Fiddle::TYPE_VOIDP,  # lpCPInfoEx : CPINFOEXW* out
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "kernel32")]
extern "system" {
    fn GetCPInfoExW(
        CodePage: u32,  // DWORD
        dwFlags: u32,  // DWORD
        lpCPInfoEx: *mut CPINFOEXW  // CPINFOEXW* out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("KERNEL32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern bool GetCPInfoExW(uint CodePage, uint dwFlags, IntPtr lpCPInfoEx);
"@
$api = Add-Type -MemberDefinition $sig -Name 'KERNEL32_GetCPInfoExW' -Namespace Win32 -PassThru
# $api::GetCPInfoExW(CodePage, dwFlags, lpCPInfoEx)

#uselib "KERNEL32.dll"
#func global GetCPInfoExW "GetCPInfoExW" wptr, wptr, wptr
; GetCPInfoExW CodePage, dwFlags, varptr(lpCPInfoEx)   ; 戻り値は stat
; CodePage : DWORD -> "wptr"
; dwFlags : DWORD -> "wptr"
; lpCPInfoEx : CPINFOEXW* 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 "KERNEL32.dll"
#cfunc global GetCPInfoExW "GetCPInfoExW" int, int, var
; res = GetCPInfoExW(CodePage, dwFlags, lpCPInfoEx)
; CodePage : DWORD -> "int"
; dwFlags : DWORD -> "int"
; lpCPInfoEx : CPINFOEXW* 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 GetCPInfoExW(DWORD CodePage, DWORD dwFlags, CPINFOEXW* lpCPInfoEx)
#uselib "KERNEL32.dll"
#cfunc global GetCPInfoExW "GetCPInfoExW" int, int, var
; res = GetCPInfoExW(CodePage, dwFlags, lpCPInfoEx)
; CodePage : DWORD -> "int"
; dwFlags : DWORD -> "int"
; lpCPInfoEx : CPINFOEXW* 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 (
	kernel32 = windows.NewLazySystemDLL("KERNEL32.dll")
	procGetCPInfoExW = kernel32.NewProc("GetCPInfoExW")
)

// CodePage (DWORD), dwFlags (DWORD), lpCPInfoEx (CPINFOEXW* out)
r1, _, err := procGetCPInfoExW.Call(
	uintptr(CodePage),
	uintptr(dwFlags),
	uintptr(lpCPInfoEx),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function GetCPInfoExW(
  CodePage: DWORD;   // DWORD
  dwFlags: DWORD;   // DWORD
  lpCPInfoEx: Pointer   // CPINFOEXW* out
): BOOL; stdcall;
  external 'KERNEL32.dll' name 'GetCPInfoExW';

result := DllCall("KERNEL32\GetCPInfoExW"
    , "UInt", CodePage   ; DWORD
    , "UInt", dwFlags   ; DWORD
    , "Ptr", lpCPInfoEx   ; CPINFOEXW* out
    , "Int")   ; return: BOOL

●GetCPInfoExW(CodePage, dwFlags, lpCPInfoEx) = DLL("KERNEL32.dll", "bool GetCPInfoExW(dword, dword, void*)")
# 呼び出し: GetCPInfoExW(CodePage, dwFlags, lpCPInfoEx)
# CodePage : DWORD -> "dword"
# dwFlags : DWORD -> "dword"
# lpCPInfoEx : CPINFOEXW* 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。