GetUserNameExW

// SECUR32.dll  (Unicode / -W)
#include <windows.h>

BOOLEAN GetUserNameExW(
    EXTENDED_NAME_FORMAT NameFormat,
    LPWSTR lpNameBuffer,   // optional
    DWORD* nSize
);

<DllImport("SECUR32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetUserNameExW(
    NameFormat As Integer,   ' EXTENDED_NAME_FORMAT
    <MarshalAs(UnmanagedType.LPWStr)> lpNameBuffer As System.Text.StringBuilder,   ' LPWSTR optional, out
    ByRef nSize As UInteger   ' DWORD* in/out
) As Byte
End Function

' NameFormat : EXTENDED_NAME_FORMAT
' lpNameBuffer : LPWSTR optional, out
' nSize : DWORD* in/out
Declare PtrSafe Function GetUserNameExW Lib "secur32" ( _
    ByVal NameFormat As Long, _
    ByVal lpNameBuffer As LongPtr, _
    ByRef nSize As Long) As Byte
' 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

GetUserNameExW = ctypes.windll.secur32.GetUserNameExW
GetUserNameExW.restype = ctypes.c_byte
GetUserNameExW.argtypes = [
    ctypes.c_int,  # NameFormat : EXTENDED_NAME_FORMAT
    wintypes.LPWSTR,  # lpNameBuffer : LPWSTR optional, out
    ctypes.POINTER(wintypes.DWORD),  # nSize : DWORD* in/out
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SECUR32.dll')
GetUserNameExW = Fiddle::Function.new(
  lib['GetUserNameExW'],
  [
    Fiddle::TYPE_INT,  # NameFormat : EXTENDED_NAME_FORMAT
    Fiddle::TYPE_VOIDP,  # lpNameBuffer : LPWSTR optional, out
    Fiddle::TYPE_VOIDP,  # nSize : DWORD* in/out
  ],
  Fiddle::TYPE_CHAR)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "secur32")]
extern "system" {
    fn GetUserNameExW(
        NameFormat: i32,  // EXTENDED_NAME_FORMAT
        lpNameBuffer: *mut u16,  // LPWSTR optional, out
        nSize: *mut u32  // DWORD* in/out
    ) -> u8;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("SECUR32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern byte GetUserNameExW(int NameFormat, [MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder lpNameBuffer, ref uint nSize);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SECUR32_GetUserNameExW' -Namespace Win32 -PassThru
# $api::GetUserNameExW(NameFormat, lpNameBuffer, nSize)

#uselib "SECUR32.dll"
#func global GetUserNameExW "GetUserNameExW" wptr, wptr, wptr
; GetUserNameExW NameFormat, varptr(lpNameBuffer), varptr(nSize)   ; 戻り値は stat
; NameFormat : EXTENDED_NAME_FORMAT -> "wptr"
; lpNameBuffer : LPWSTR optional, out -> "wptr"
; nSize : DWORD* in/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 "SECUR32.dll"
#cfunc global GetUserNameExW "GetUserNameExW" int, var, var
; res = GetUserNameExW(NameFormat, lpNameBuffer, nSize)
; NameFormat : EXTENDED_NAME_FORMAT -> "int"
; lpNameBuffer : LPWSTR optional, out -> "var"
; nSize : DWORD* in/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。

; BOOLEAN GetUserNameExW(EXTENDED_NAME_FORMAT NameFormat, LPWSTR lpNameBuffer, DWORD* nSize)
#uselib "SECUR32.dll"
#cfunc global GetUserNameExW "GetUserNameExW" int, var, var
; res = GetUserNameExW(NameFormat, lpNameBuffer, nSize)
; NameFormat : EXTENDED_NAME_FORMAT -> "int"
; lpNameBuffer : LPWSTR optional, out -> "var"
; nSize : DWORD* in/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 (
	secur32 = windows.NewLazySystemDLL("SECUR32.dll")
	procGetUserNameExW = secur32.NewProc("GetUserNameExW")
)

// NameFormat (EXTENDED_NAME_FORMAT), lpNameBuffer (LPWSTR optional, out), nSize (DWORD* in/out)
r1, _, err := procGetUserNameExW.Call(
	uintptr(NameFormat),
	uintptr(lpNameBuffer),
	uintptr(nSize),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOLEAN

function GetUserNameExW(
  NameFormat: Integer;   // EXTENDED_NAME_FORMAT
  lpNameBuffer: PWideChar;   // LPWSTR optional, out
  nSize: Pointer   // DWORD* in/out
): ByteBool; stdcall;
  external 'SECUR32.dll' name 'GetUserNameExW';

result := DllCall("SECUR32\GetUserNameExW"
    , "Int", NameFormat   ; EXTENDED_NAME_FORMAT
    , "Ptr", lpNameBuffer   ; LPWSTR optional, out
    , "Ptr", nSize   ; DWORD* in/out
    , "Char")   ; return: BOOLEAN

●GetUserNameExW(NameFormat, lpNameBuffer, nSize) = DLL("SECUR32.dll", "byte GetUserNameExW(int, char*, void*)")
# 呼び出し: GetUserNameExW(NameFormat, lpNameBuffer, nSize)
# NameFormat : EXTENDED_NAME_FORMAT -> "int"
# lpNameBuffer : LPWSTR optional, out -> "char*"
# nSize : DWORD* in/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。