RegQueryValueExA

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

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

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

import ctypes
from ctypes import wintypes

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

#[link(name = "advapi32")]
extern "system" {
    fn RegQueryValueExA(
        hKey: *mut core::ffi::c_void,  // HKEY
        lpValueName: *const u8,  // LPCSTR 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.Ansi)]
public static extern uint RegQueryValueExA(IntPtr hKey, [MarshalAs(UnmanagedType.LPStr)] string lpValueName, IntPtr lpReserved, IntPtr lpType, IntPtr lpData, IntPtr lpcbData);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ADVAPI32_RegQueryValueExA' -Namespace Win32 -PassThru
# $api::RegQueryValueExA(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)

#uselib "ADVAPI32.dll"
#func global RegQueryValueExA "RegQueryValueExA" sptr, sptr, sptr, sptr, sptr, sptr
; RegQueryValueExA hKey, lpValueName, varptr(lpReserved), lpType, varptr(lpData), varptr(lpcbData)   ; 戻り値は stat
; hKey : HKEY -> "sptr"
; lpValueName : LPCSTR optional -> "sptr"
; lpReserved : DWORD* optional -> "sptr"
; lpType : REG_VALUE_TYPE* optional, out -> "sptr"
; lpData : BYTE* optional, out -> "sptr"
; lpcbData : DWORD* optional, in/out -> "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 RegQueryValueExA "RegQueryValueExA" sptr, str, var, int, var, var
; res = RegQueryValueExA(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)
; hKey : HKEY -> "sptr"
; lpValueName : LPCSTR optional -> "str"
; 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 RegQueryValueExA(HKEY hKey, LPCSTR lpValueName, DWORD* lpReserved, REG_VALUE_TYPE* lpType, BYTE* lpData, DWORD* lpcbData)
#uselib "ADVAPI32.dll"
#cfunc global RegQueryValueExA "RegQueryValueExA" intptr, str, var, int, var, var
; res = RegQueryValueExA(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)
; hKey : HKEY -> "intptr"
; lpValueName : LPCSTR optional -> "str"
; 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")
	procRegQueryValueExA = advapi32.NewProc("RegQueryValueExA")
)

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

function RegQueryValueExA(
  hKey: THandle;   // HKEY
  lpValueName: PAnsiChar;   // LPCSTR 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 'RegQueryValueExA';

result := DllCall("ADVAPI32\RegQueryValueExA"
    , "Ptr", hKey   ; HKEY
    , "AStr", lpValueName   ; LPCSTR 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

●RegQueryValueExA(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData) = DLL("ADVAPI32.dll", "dword RegQueryValueExA(void*, char*, void*, void*, void*, void*)")
# 呼び出し: RegQueryValueExA(hKey, lpValueName, lpReserved, lpType, lpData, lpcbData)
# hKey : HKEY -> "void*"
# lpValueName : LPCSTR 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)。