RegSetValueExA

// ADVAPI32.dll  (ANSI / -A)
#include <windows.h>

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

<DllImport("ADVAPI32.dll", CharSet:=CharSet.Ansi, ExactSpelling:=True)>
Public Shared Function RegSetValueExA(
    hKey As IntPtr,   ' HKEY
    <MarshalAs(UnmanagedType.LPStr)> lpValueName As String,   ' LPCSTR 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 : LPCSTR optional
' Reserved : DWORD optional
' dwType : REG_VALUE_TYPE
' lpData : BYTE* optional
' cbData : DWORD
Declare PtrSafe Function RegSetValueExA Lib "advapi32" ( _
    ByVal hKey As LongPtr, _
    ByVal lpValueName As String, _
    ByVal Reserved As Long, _
    ByVal dwType As Long, _
    ByVal lpData As LongPtr, _
    ByVal cbData As Long) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

RegSetValueExA = ctypes.windll.advapi32.RegSetValueExA
RegSetValueExA.restype = wintypes.DWORD
RegSetValueExA.argtypes = [
    wintypes.HANDLE,  # hKey : HKEY
    wintypes.LPCSTR,  # lpValueName : LPCSTR 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')
RegSetValueExA = Fiddle::Function.new(
  lib['RegSetValueExA'],
  [
    Fiddle::TYPE_VOIDP,  # hKey : HKEY
    Fiddle::TYPE_VOIDP,  # lpValueName : LPCSTR 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)

#[link(name = "advapi32")]
extern "system" {
    fn RegSetValueExA(
        hKey: *mut core::ffi::c_void,  // HKEY
        lpValueName: *const u8,  // LPCSTR 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.Ansi)]
public static extern uint RegSetValueExA(IntPtr hKey, [MarshalAs(UnmanagedType.LPStr)] string lpValueName, uint Reserved, uint dwType, IntPtr lpData, uint cbData);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ADVAPI32_RegSetValueExA' -Namespace Win32 -PassThru
# $api::RegSetValueExA(hKey, lpValueName, Reserved, dwType, lpData, cbData)

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

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

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

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

●RegSetValueExA(hKey, lpValueName, Reserved, dwType, lpData, cbData) = DLL("ADVAPI32.dll", "dword RegSetValueExA(void*, char*, dword, dword, void*, dword)")
# 呼び出し: RegSetValueExA(hKey, lpValueName, Reserved, dwType, lpData, cbData)
# hKey : HKEY -> "void*"
# lpValueName : LPCSTR 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)。