RegQueryValueA

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

WIN32_ERROR RegQueryValueA(
    HKEY hKey,
    LPCSTR lpSubKey,   // optional
    LPSTR lpData,   // optional
    INT* lpcbData   // optional
);

<DllImport("ADVAPI32.dll", CharSet:=CharSet.Ansi, ExactSpelling:=True)>
Public Shared Function RegQueryValueA(
    hKey As IntPtr,   ' HKEY
    <MarshalAs(UnmanagedType.LPStr)> lpSubKey As String,   ' LPCSTR optional
    <MarshalAs(UnmanagedType.LPStr)> lpData As System.Text.StringBuilder,   ' LPSTR optional, out
    lpcbData As IntPtr   ' INT* optional, in/out
) As UInteger
End Function

' hKey : HKEY
' lpSubKey : LPCSTR optional
' lpData : LPSTR optional, out
' lpcbData : INT* optional, in/out
Declare PtrSafe Function RegQueryValueA Lib "advapi32" ( _
    ByVal hKey As LongPtr, _
    ByVal lpSubKey As String, _
    ByVal lpData As String, _
    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

RegQueryValueA = ctypes.windll.advapi32.RegQueryValueA
RegQueryValueA.restype = wintypes.DWORD
RegQueryValueA.argtypes = [
    wintypes.HANDLE,  # hKey : HKEY
    wintypes.LPCSTR,  # lpSubKey : LPCSTR optional
    wintypes.LPSTR,  # lpData : LPSTR optional, out
    ctypes.POINTER(ctypes.c_int),  # lpcbData : INT* optional, in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('ADVAPI32.dll')
RegQueryValueA = Fiddle::Function.new(
  lib['RegQueryValueA'],
  [
    Fiddle::TYPE_VOIDP,  # hKey : HKEY
    Fiddle::TYPE_VOIDP,  # lpSubKey : LPCSTR optional
    Fiddle::TYPE_VOIDP,  # lpData : LPSTR optional, out
    Fiddle::TYPE_VOIDP,  # lpcbData : INT* optional, in/out
  ],
  -Fiddle::TYPE_INT)

#[link(name = "advapi32")]
extern "system" {
    fn RegQueryValueA(
        hKey: *mut core::ffi::c_void,  // HKEY
        lpSubKey: *const u8,  // LPCSTR optional
        lpData: *mut u8,  // LPSTR optional, out
        lpcbData: *mut i32  // INT* 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 RegQueryValueA(IntPtr hKey, [MarshalAs(UnmanagedType.LPStr)] string lpSubKey, [MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder lpData, IntPtr lpcbData);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ADVAPI32_RegQueryValueA' -Namespace Win32 -PassThru
# $api::RegQueryValueA(hKey, lpSubKey, lpData, lpcbData)

#uselib "ADVAPI32.dll"
#func global RegQueryValueA "RegQueryValueA" sptr, sptr, sptr, sptr
; RegQueryValueA hKey, lpSubKey, varptr(lpData), varptr(lpcbData)   ; 戻り値は stat
; hKey : HKEY -> "sptr"
; lpSubKey : LPCSTR optional -> "sptr"
; lpData : LPSTR optional, out -> "sptr"
; lpcbData : INT* 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 RegQueryValueA "RegQueryValueA" sptr, str, var, var
; res = RegQueryValueA(hKey, lpSubKey, lpData, lpcbData)
; hKey : HKEY -> "sptr"
; lpSubKey : LPCSTR optional -> "str"
; lpData : LPSTR optional, out -> "var"
; lpcbData : INT* 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 RegQueryValueA(HKEY hKey, LPCSTR lpSubKey, LPSTR lpData, INT* lpcbData)
#uselib "ADVAPI32.dll"
#cfunc global RegQueryValueA "RegQueryValueA" intptr, str, var, var
; res = RegQueryValueA(hKey, lpSubKey, lpData, lpcbData)
; hKey : HKEY -> "intptr"
; lpSubKey : LPCSTR optional -> "str"
; lpData : LPSTR optional, out -> "var"
; lpcbData : INT* 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")
	procRegQueryValueA = advapi32.NewProc("RegQueryValueA")
)

// hKey (HKEY), lpSubKey (LPCSTR optional), lpData (LPSTR optional, out), lpcbData (INT* optional, in/out)
r1, _, err := procRegQueryValueA.Call(
	uintptr(hKey),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(lpSubKey))),
	uintptr(lpData),
	uintptr(lpcbData),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // WIN32_ERROR

function RegQueryValueA(
  hKey: THandle;   // HKEY
  lpSubKey: PAnsiChar;   // LPCSTR optional
  lpData: PAnsiChar;   // LPSTR optional, out
  lpcbData: Pointer   // INT* optional, in/out
): DWORD; stdcall;
  external 'ADVAPI32.dll' name 'RegQueryValueA';

result := DllCall("ADVAPI32\RegQueryValueA"
    , "Ptr", hKey   ; HKEY
    , "AStr", lpSubKey   ; LPCSTR optional
    , "Ptr", lpData   ; LPSTR optional, out
    , "Ptr", lpcbData   ; INT* optional, in/out
    , "UInt")   ; return: WIN32_ERROR

●RegQueryValueA(hKey, lpSubKey, lpData, lpcbData) = DLL("ADVAPI32.dll", "dword RegQueryValueA(void*, char*, char*, void*)")
# 呼び出し: RegQueryValueA(hKey, lpSubKey, lpData, lpcbData)
# hKey : HKEY -> "void*"
# lpSubKey : LPCSTR optional -> "char*"
# lpData : LPSTR optional, out -> "char*"
# lpcbData : INT* 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)。