VariantToString

// PROPSYS.dll
#include <windows.h>

HRESULT VariantToString(
    const VARIANT* varIn,
    LPWSTR pszBuf,
    DWORD cchBuf
);

<DllImport("PROPSYS.dll", ExactSpelling:=True)>
Public Shared Function VariantToString(
    varIn As IntPtr,   ' VARIANT*
    <MarshalAs(UnmanagedType.LPWStr)> pszBuf As System.Text.StringBuilder,   ' LPWSTR out
    cchBuf As UInteger   ' DWORD
) As Integer
End Function

' varIn : VARIANT*
' pszBuf : LPWSTR out
' cchBuf : DWORD
Declare PtrSafe Function VariantToString Lib "propsys" ( _
    ByVal varIn As LongPtr, _
    ByVal pszBuf As LongPtr, _
    ByVal cchBuf 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

VariantToString = ctypes.windll.propsys.VariantToString
VariantToString.restype = ctypes.c_int
VariantToString.argtypes = [
    ctypes.c_void_p,  # varIn : VARIANT*
    wintypes.LPWSTR,  # pszBuf : LPWSTR out
    wintypes.DWORD,  # cchBuf : DWORD
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('PROPSYS.dll')
VariantToString = Fiddle::Function.new(
  lib['VariantToString'],
  [
    Fiddle::TYPE_VOIDP,  # varIn : VARIANT*
    Fiddle::TYPE_VOIDP,  # pszBuf : LPWSTR out
    -Fiddle::TYPE_INT,  # cchBuf : DWORD
  ],
  Fiddle::TYPE_INT)

#[link(name = "propsys")]
extern "system" {
    fn VariantToString(
        varIn: *const VARIANT,  // VARIANT*
        pszBuf: *mut u16,  // LPWSTR out
        cchBuf: u32  // DWORD
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("PROPSYS.dll")]
public static extern int VariantToString(IntPtr varIn, [MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder pszBuf, uint cchBuf);
"@
$api = Add-Type -MemberDefinition $sig -Name 'PROPSYS_VariantToString' -Namespace Win32 -PassThru
# $api::VariantToString(varIn, pszBuf, cchBuf)

#uselib "PROPSYS.dll"
#func global VariantToString "VariantToString" sptr, sptr, sptr
; VariantToString varptr(varIn), varptr(pszBuf), cchBuf   ; 戻り値は stat
; varIn : VARIANT* -> "sptr"
; pszBuf : LPWSTR out -> "sptr"
; cchBuf : 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 "PROPSYS.dll"
#cfunc global VariantToString "VariantToString" var, var, int
; res = VariantToString(varIn, pszBuf, cchBuf)
; varIn : VARIANT* -> "var"
; pszBuf : LPWSTR out -> "var"
; cchBuf : 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。

; HRESULT VariantToString(VARIANT* varIn, LPWSTR pszBuf, DWORD cchBuf)
#uselib "PROPSYS.dll"
#cfunc global VariantToString "VariantToString" var, var, int
; res = VariantToString(varIn, pszBuf, cchBuf)
; varIn : VARIANT* -> "var"
; pszBuf : LPWSTR out -> "var"
; cchBuf : 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 (
	propsys = windows.NewLazySystemDLL("PROPSYS.dll")
	procVariantToString = propsys.NewProc("VariantToString")
)

// varIn (VARIANT*), pszBuf (LPWSTR out), cchBuf (DWORD)
r1, _, err := procVariantToString.Call(
	uintptr(varIn),
	uintptr(pszBuf),
	uintptr(cchBuf),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function VariantToString(
  varIn: Pointer;   // VARIANT*
  pszBuf: PWideChar;   // LPWSTR out
  cchBuf: DWORD   // DWORD
): Integer; stdcall;
  external 'PROPSYS.dll' name 'VariantToString';

result := DllCall("PROPSYS\VariantToString"
    , "Ptr", varIn   ; VARIANT*
    , "Ptr", pszBuf   ; LPWSTR out
    , "UInt", cchBuf   ; DWORD
    , "Int")   ; return: HRESULT

●VariantToString(varIn, pszBuf, cchBuf) = DLL("PROPSYS.dll", "int VariantToString(void*, char*, dword)")
# 呼び出し: VariantToString(varIn, pszBuf, cchBuf)
# varIn : VARIANT* -> "void*"
# pszBuf : LPWSTR out -> "char*"
# cchBuf : 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)。