MsiGetProductInfoA

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

DWORD MsiGetProductInfoA(
    LPCSTR szProduct,
    LPCSTR szAttribute,
    LPSTR lpValueBuf,   // optional
    DWORD* pcchValueBuf   // optional
);

<DllImport("msi.dll", CharSet:=CharSet.Ansi, ExactSpelling:=True)>
Public Shared Function MsiGetProductInfoA(
    <MarshalAs(UnmanagedType.LPStr)> szProduct As String,   ' LPCSTR
    <MarshalAs(UnmanagedType.LPStr)> szAttribute As String,   ' LPCSTR
    <MarshalAs(UnmanagedType.LPStr)> lpValueBuf As System.Text.StringBuilder,   ' LPSTR optional, out
    pcchValueBuf As IntPtr   ' DWORD* optional, in/out
) As UInteger
End Function

' szProduct : LPCSTR
' szAttribute : LPCSTR
' lpValueBuf : LPSTR optional, out
' pcchValueBuf : DWORD* optional, in/out
Declare PtrSafe Function MsiGetProductInfoA Lib "msi" ( _
    ByVal szProduct As String, _
    ByVal szAttribute As String, _
    ByVal lpValueBuf As String, _
    ByVal pcchValueBuf 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

MsiGetProductInfoA = ctypes.windll.msi.MsiGetProductInfoA
MsiGetProductInfoA.restype = wintypes.DWORD
MsiGetProductInfoA.argtypes = [
    wintypes.LPCSTR,  # szProduct : LPCSTR
    wintypes.LPCSTR,  # szAttribute : LPCSTR
    wintypes.LPSTR,  # lpValueBuf : LPSTR optional, out
    ctypes.POINTER(wintypes.DWORD),  # pcchValueBuf : DWORD* optional, in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('msi.dll')
MsiGetProductInfoA = Fiddle::Function.new(
  lib['MsiGetProductInfoA'],
  [
    Fiddle::TYPE_VOIDP,  # szProduct : LPCSTR
    Fiddle::TYPE_VOIDP,  # szAttribute : LPCSTR
    Fiddle::TYPE_VOIDP,  # lpValueBuf : LPSTR optional, out
    Fiddle::TYPE_VOIDP,  # pcchValueBuf : DWORD* optional, in/out
  ],
  -Fiddle::TYPE_INT)

#[link(name = "msi")]
extern "system" {
    fn MsiGetProductInfoA(
        szProduct: *const u8,  // LPCSTR
        szAttribute: *const u8,  // LPCSTR
        lpValueBuf: *mut u8,  // LPSTR optional, out
        pcchValueBuf: *mut u32  // DWORD* optional, in/out
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("msi.dll", CharSet = CharSet.Ansi)]
public static extern uint MsiGetProductInfoA([MarshalAs(UnmanagedType.LPStr)] string szProduct, [MarshalAs(UnmanagedType.LPStr)] string szAttribute, [MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder lpValueBuf, IntPtr pcchValueBuf);
"@
$api = Add-Type -MemberDefinition $sig -Name 'msi_MsiGetProductInfoA' -Namespace Win32 -PassThru
# $api::MsiGetProductInfoA(szProduct, szAttribute, lpValueBuf, pcchValueBuf)

#uselib "msi.dll"
#func global MsiGetProductInfoA "MsiGetProductInfoA" sptr, sptr, sptr, sptr
; MsiGetProductInfoA szProduct, szAttribute, varptr(lpValueBuf), varptr(pcchValueBuf)   ; 戻り値は stat
; szProduct : LPCSTR -> "sptr"
; szAttribute : LPCSTR -> "sptr"
; lpValueBuf : LPSTR optional, out -> "sptr"
; pcchValueBuf : 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 "msi.dll"
#cfunc global MsiGetProductInfoA "MsiGetProductInfoA" str, str, var, var
; res = MsiGetProductInfoA(szProduct, szAttribute, lpValueBuf, pcchValueBuf)
; szProduct : LPCSTR -> "str"
; szAttribute : LPCSTR -> "str"
; lpValueBuf : LPSTR optional, out -> "var"
; pcchValueBuf : 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。

; DWORD MsiGetProductInfoA(LPCSTR szProduct, LPCSTR szAttribute, LPSTR lpValueBuf, DWORD* pcchValueBuf)
#uselib "msi.dll"
#cfunc global MsiGetProductInfoA "MsiGetProductInfoA" str, str, var, var
; res = MsiGetProductInfoA(szProduct, szAttribute, lpValueBuf, pcchValueBuf)
; szProduct : LPCSTR -> "str"
; szAttribute : LPCSTR -> "str"
; lpValueBuf : LPSTR optional, out -> "var"
; pcchValueBuf : 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 (
	msi = windows.NewLazySystemDLL("msi.dll")
	procMsiGetProductInfoA = msi.NewProc("MsiGetProductInfoA")
)

// szProduct (LPCSTR), szAttribute (LPCSTR), lpValueBuf (LPSTR optional, out), pcchValueBuf (DWORD* optional, in/out)
r1, _, err := procMsiGetProductInfoA.Call(
	uintptr(unsafe.Pointer(windows.BytePtrFromString(szProduct))),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(szAttribute))),
	uintptr(lpValueBuf),
	uintptr(pcchValueBuf),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function MsiGetProductInfoA(
  szProduct: PAnsiChar;   // LPCSTR
  szAttribute: PAnsiChar;   // LPCSTR
  lpValueBuf: PAnsiChar;   // LPSTR optional, out
  pcchValueBuf: Pointer   // DWORD* optional, in/out
): DWORD; stdcall;
  external 'msi.dll' name 'MsiGetProductInfoA';

result := DllCall("msi\MsiGetProductInfoA"
    , "AStr", szProduct   ; LPCSTR
    , "AStr", szAttribute   ; LPCSTR
    , "Ptr", lpValueBuf   ; LPSTR optional, out
    , "Ptr", pcchValueBuf   ; DWORD* optional, in/out
    , "UInt")   ; return: DWORD

●MsiGetProductInfoA(szProduct, szAttribute, lpValueBuf, pcchValueBuf) = DLL("msi.dll", "dword MsiGetProductInfoA(char*, char*, char*, void*)")
# 呼び出し: MsiGetProductInfoA(szProduct, szAttribute, lpValueBuf, pcchValueBuf)
# szProduct : LPCSTR -> "char*"
# szAttribute : LPCSTR -> "char*"
# lpValueBuf : LPSTR optional, out -> "char*"
# pcchValueBuf : 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)。