RegSetValueExW

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

WIN32_ERROR RegSetValueExW(
    HKEY hKey,
    LPCWSTR lpValueName,   // optional
    DWORD Reserved,   // optional
    REG_VALUE_TYPE dwType,
    const BYTE* lpData,   // optional
    DWORD cbData
);

<DllImport("ADVAPI32.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function RegSetValueExW(
    hKey As IntPtr,   ' HKEY
    <MarshalAs(UnmanagedType.LPWStr)> lpValueName As String,   ' LPCWSTR optional
    Reserved As UInteger,   ' DWORD optional
    dwType As UInteger,   ' REG_VALUE_TYPE
    lpData As IntPtr,   ' BYTE* optional
    cbData As UInteger   ' DWORD
) As UInteger
End Function

' hKey : HKEY
' lpValueName : LPCWSTR optional
' Reserved : DWORD optional
' dwType : REG_VALUE_TYPE
' lpData : BYTE* optional
' cbData : DWORD
Declare PtrSafe Function RegSetValueExW Lib "advapi32" ( _
    ByVal hKey As LongPtr, _
    ByVal lpValueName As LongPtr, _
    ByVal Reserved As Long, _
    ByVal dwType As Long, _
    ByVal lpData As LongPtr, _
    ByVal cbData As Long) 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

RegSetValueExW = ctypes.windll.advapi32.RegSetValueExW
RegSetValueExW.restype = wintypes.DWORD
RegSetValueExW.argtypes = [
    wintypes.HANDLE,  # hKey : HKEY
    wintypes.LPCWSTR,  # lpValueName : LPCWSTR optional
    wintypes.DWORD,  # Reserved : DWORD optional
    wintypes.DWORD,  # dwType : REG_VALUE_TYPE
    ctypes.POINTER(ctypes.c_ubyte),  # lpData : BYTE* optional
    wintypes.DWORD,  # cbData : DWORD
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('ADVAPI32.dll')
RegSetValueExW = Fiddle::Function.new(
  lib['RegSetValueExW'],
  [
    Fiddle::TYPE_VOIDP,  # hKey : HKEY
    Fiddle::TYPE_VOIDP,  # lpValueName : LPCWSTR optional
    -Fiddle::TYPE_INT,  # Reserved : DWORD optional
    -Fiddle::TYPE_INT,  # dwType : REG_VALUE_TYPE
    Fiddle::TYPE_VOIDP,  # lpData : BYTE* optional
    -Fiddle::TYPE_INT,  # cbData : DWORD
  ],
  -Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

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

$sig = @"
[DllImport("ADVAPI32.dll", CharSet = CharSet.Unicode)]
public static extern uint RegSetValueExW(IntPtr hKey, [MarshalAs(UnmanagedType.LPWStr)] string lpValueName, uint Reserved, uint dwType, IntPtr lpData, uint cbData);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ADVAPI32_RegSetValueExW' -Namespace Win32 -PassThru
# $api::RegSetValueExW(hKey, lpValueName, Reserved, dwType, lpData, cbData)

#uselib "ADVAPI32.dll"
#func global RegSetValueExW "RegSetValueExW" wptr, wptr, wptr, wptr, wptr, wptr
; RegSetValueExW hKey, lpValueName, Reserved, dwType, varptr(lpData), cbData   ; 戻り値は stat
; hKey : HKEY -> "wptr"
; lpValueName : LPCWSTR optional -> "wptr"
; Reserved : DWORD optional -> "wptr"
; dwType : REG_VALUE_TYPE -> "wptr"
; lpData : BYTE* optional -> "wptr"
; cbData : DWORD -> "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 RegSetValueExW "RegSetValueExW" sptr, wstr, int, int, var, int
; res = RegSetValueExW(hKey, lpValueName, Reserved, dwType, lpData, cbData)
; hKey : HKEY -> "sptr"
; lpValueName : LPCWSTR optional -> "wstr"
; Reserved : DWORD optional -> "int"
; dwType : REG_VALUE_TYPE -> "int"
; lpData : BYTE* optional -> "var"
; cbData : DWORD -> "int"
; ※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 RegSetValueExW(HKEY hKey, LPCWSTR lpValueName, DWORD Reserved, REG_VALUE_TYPE dwType, BYTE* lpData, DWORD cbData)
#uselib "ADVAPI32.dll"
#cfunc global RegSetValueExW "RegSetValueExW" intptr, wstr, int, int, var, int
; res = RegSetValueExW(hKey, lpValueName, Reserved, dwType, lpData, cbData)
; hKey : HKEY -> "intptr"
; lpValueName : LPCWSTR optional -> "wstr"
; Reserved : DWORD optional -> "int"
; dwType : REG_VALUE_TYPE -> "int"
; lpData : BYTE* optional -> "var"
; cbData : DWORD -> "int"
; ※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")
	procRegSetValueExW = advapi32.NewProc("RegSetValueExW")
)

// hKey (HKEY), lpValueName (LPCWSTR optional), Reserved (DWORD optional), dwType (REG_VALUE_TYPE), lpData (BYTE* optional), cbData (DWORD)
r1, _, err := procRegSetValueExW.Call(
	uintptr(hKey),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpValueName))),
	uintptr(Reserved),
	uintptr(dwType),
	uintptr(lpData),
	uintptr(cbData),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // WIN32_ERROR

function RegSetValueExW(
  hKey: THandle;   // HKEY
  lpValueName: PWideChar;   // LPCWSTR optional
  Reserved: DWORD;   // DWORD optional
  dwType: DWORD;   // REG_VALUE_TYPE
  lpData: Pointer;   // BYTE* optional
  cbData: DWORD   // DWORD
): DWORD; stdcall;
  external 'ADVAPI32.dll' name 'RegSetValueExW';

result := DllCall("ADVAPI32\RegSetValueExW"
    , "Ptr", hKey   ; HKEY
    , "WStr", lpValueName   ; LPCWSTR optional
    , "UInt", Reserved   ; DWORD optional
    , "UInt", dwType   ; REG_VALUE_TYPE
    , "Ptr", lpData   ; BYTE* optional
    , "UInt", cbData   ; DWORD
    , "UInt")   ; return: WIN32_ERROR

●RegSetValueExW(hKey, lpValueName, Reserved, dwType, lpData, cbData) = DLL("ADVAPI32.dll", "dword RegSetValueExW(void*, char*, dword, dword, void*, dword)")
# 呼び出し: RegSetValueExW(hKey, lpValueName, Reserved, dwType, lpData, cbData)
# hKey : HKEY -> "void*"
# lpValueName : LPCWSTR optional -> "char*"
# Reserved : DWORD optional -> "dword"
# dwType : REG_VALUE_TYPE -> "dword"
# lpData : BYTE* optional -> "void*"
# cbData : DWORD -> "dword"
# 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。