RegQueryValueExW

// ADVAPI32.dll  (Unicode / -W)
#include <windows.h>

WIN32_ERROR RegQueryValueExW(
    HKEY hKey,
    LPCWSTR lpValueName,   // optional
    DWORD* lpReserved,   // optional
    REG_VALUE_TYPE* lpType,   // optional
    BYTE* lpData,   // optional
    DWORD* lpcbData   // optional
);

<DllImport("ADVAPI32.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function RegQueryValueExW(
    hKey As IntPtr,   ' HKEY
    <MarshalAs(UnmanagedType.LPWStr)> lpValueName As String,   ' LPCWSTR optional
    lpReserved As IntPtr,   ' DWORD* optional
    lpType As IntPtr,   ' REG_VALUE_TYPE* optional, out
    lpData As IntPtr,   ' BYTE* optional, out
    lpcbData As IntPtr   ' DWORD* optional, in/out
) As UInteger
End Function

' hKey : HKEY
' lpValueName : LPCWSTR optional
' lpReserved : DWORD* optional
' lpType : REG_VALUE_TYPE* optional, out
' lpData : BYTE* optional, out
' lpcbData : DWORD* optional, in/out
Declare PtrSafe Function RegQueryValueExW Lib "advapi32" ( _
    ByVal hKey As LongPtr, _
    ByVal lpValueName As LongPtr, _
    ByVal lpReserved As LongPtr, _
    ByVal lpType As LongPtr, _
    ByVal lpData As LongPtr, _
    ByVal lpcbData 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

RegQueryValueExW = ctypes.windll.advapi32.RegQueryValueExW
RegQueryValueExW.restype = wintypes.DWORD
RegQueryValueExW.argtypes = [
    wintypes.HANDLE,  # hKey : HKEY
    wintypes.LPCWSTR,  # lpValueName : LPCWSTR optional
    ctypes.POINTER(wintypes.DWORD),  # lpReserved : DWORD* optional
    ctypes.c_void_p,  # lpType : REG_VALUE_TYPE* optional, out
    ctypes.POINTER(ctypes.c_ubyte),  # lpData : BYTE* optional, out
    ctypes.POINTER(wintypes.DWORD),  # lpcbData : DWORD* optional, in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('ADVAPI32.dll')
RegQueryValueExW = Fiddle::Function.new(
  lib['RegQueryValueExW'],
  [
    Fiddle::TYPE_VOIDP,  # hKey : HKEY
    Fiddle::TYPE_VOIDP,  # lpValueName : LPCWSTR optional
    Fiddle::TYPE_VOIDP,  # lpReserved : DWORD* optional
    Fiddle::TYPE_VOIDP,  # lpType : REG_VALUE_TYPE* optional, out
    Fiddle::TYPE_VOIDP,  # lpData : BYTE* optional, out
    Fiddle::TYPE_VOIDP,  # lpcbData : DWORD* optional, in/out
  ],
  -Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "advapi32")]
extern "system" {
    fn RegQueryValueExW(
        hKey: *mut core::ffi::c_void,  // HKEY
        lpValueName: *const u16,  // LPCWSTR optional
        lpReserved: *mut u32,  // DWORD* optional
        lpType: *mut u32,  // REG_VALUE_TYPE* optional, out
        lpData: *mut u8,  // BYTE* optional, out
        lpcbData: *mut u32  // DWORD* optional, in/out
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("ADVAPI32.dll", CharSet = CharSet.Unicode)]
public static extern uint RegQueryValueExW(IntPtr hKey, [MarshalAs(UnmanagedType.LPWStr)] string lpValueName, IntPtr lpReserved, IntPtr lpType, IntPtr lpData, IntPtr lpcbData);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ADVAPI32_RegQueryValueExW' -Namespace Win32 -PassThru
# $api::RegQueryValueExW(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)

#uselib "ADVAPI32.dll"
#func global RegQueryValueExW "RegQueryValueExW" wptr, wptr, wptr, wptr, wptr, wptr
; RegQueryValueExW hKey, lpValueName, varptr(lpReserved), lpType, varptr(lpData), varptr(lpcbData)   ; 戻り値は stat
; hKey : HKEY -> "wptr"
; lpValueName : LPCWSTR optional -> "wptr"
; lpReserved : DWORD* optional -> "wptr"
; lpType : REG_VALUE_TYPE* optional, out -> "wptr"
; lpData : BYTE* optional, out -> "wptr"
; lpcbData : DWORD* optional, 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 "ADVAPI32.dll"
#cfunc global RegQueryValueExW "RegQueryValueExW" sptr, wstr, var, int, var, var
; res = RegQueryValueExW(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)
; hKey : HKEY -> "sptr"
; lpValueName : LPCWSTR optional -> "wstr"
; lpReserved : DWORD* optional -> "var"
; lpType : REG_VALUE_TYPE* optional, out -> "int"
; lpData : BYTE* optional, out -> "var"
; lpcbData : DWORD* optional, 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。

; WIN32_ERROR RegQueryValueExW(HKEY hKey, LPCWSTR lpValueName, DWORD* lpReserved, REG_VALUE_TYPE* lpType, BYTE* lpData, DWORD* lpcbData)
#uselib "ADVAPI32.dll"
#cfunc global RegQueryValueExW "RegQueryValueExW" intptr, wstr, var, int, var, var
; res = RegQueryValueExW(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)
; hKey : HKEY -> "intptr"
; lpValueName : LPCWSTR optional -> "wstr"
; lpReserved : DWORD* optional -> "var"
; lpType : REG_VALUE_TYPE* optional, out -> "int"
; lpData : BYTE* optional, out -> "var"
; lpcbData : DWORD* optional, 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 (
	advapi32 = windows.NewLazySystemDLL("ADVAPI32.dll")
	procRegQueryValueExW = advapi32.NewProc("RegQueryValueExW")
)

// hKey (HKEY), lpValueName (LPCWSTR optional), lpReserved (DWORD* optional), lpType (REG_VALUE_TYPE* optional, out), lpData (BYTE* optional, out), lpcbData (DWORD* optional, in/out)
r1, _, err := procRegQueryValueExW.Call(
	uintptr(hKey),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpValueName))),
	uintptr(lpReserved),
	uintptr(lpType),
	uintptr(lpData),
	uintptr(lpcbData),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // WIN32_ERROR

function RegQueryValueExW(
  hKey: THandle;   // HKEY
  lpValueName: PWideChar;   // LPCWSTR optional
  lpReserved: Pointer;   // DWORD* optional
  lpType: Pointer;   // REG_VALUE_TYPE* optional, out
  lpData: Pointer;   // BYTE* optional, out
  lpcbData: Pointer   // DWORD* optional, in/out
): DWORD; stdcall;
  external 'ADVAPI32.dll' name 'RegQueryValueExW';

result := DllCall("ADVAPI32\RegQueryValueExW"
    , "Ptr", hKey   ; HKEY
    , "WStr", lpValueName   ; LPCWSTR optional
    , "Ptr", lpReserved   ; DWORD* optional
    , "Ptr", lpType   ; REG_VALUE_TYPE* optional, out
    , "Ptr", lpData   ; BYTE* optional, out
    , "Ptr", lpcbData   ; DWORD* optional, in/out
    , "UInt")   ; return: WIN32_ERROR

●RegQueryValueExW(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData) = DLL("ADVAPI32.dll", "dword RegQueryValueExW(void*, char*, void*, void*, void*, void*)")
# 呼び出し: RegQueryValueExW(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)
# hKey : HKEY -> "void*"
# lpValueName : LPCWSTR optional -> "char*"
# lpReserved : DWORD* optional -> "void*"
# lpType : REG_VALUE_TYPE* optional, out -> "void*"
# lpData : BYTE* optional, out -> "void*"
# lpcbData : DWORD* optional, 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。