VariantChangeType

// OLEAUT32.dll
#include <windows.h>

HRESULT VariantChangeType(
    VARIANT* pvargDest,
    const VARIANT* pvarSrc,
    VAR_CHANGE_FLAGS wFlags,
    VARENUM vt
);

<DllImport("OLEAUT32.dll", ExactSpelling:=True)>
Public Shared Function VariantChangeType(
    pvargDest As IntPtr,   ' VARIANT* in/out
    pvarSrc As IntPtr,   ' VARIANT*
    wFlags As UShort,   ' VAR_CHANGE_FLAGS
    vt As UShort   ' VARENUM
) As Integer
End Function

' pvargDest : VARIANT* in/out
' pvarSrc : VARIANT*
' wFlags : VAR_CHANGE_FLAGS
' vt : VARENUM
Declare PtrSafe Function VariantChangeType Lib "oleaut32" ( _
    ByVal pvargDest As LongPtr, _
    ByVal pvarSrc As LongPtr, _
    ByVal wFlags As Integer, _
    ByVal vt As Integer) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

VariantChangeType = ctypes.windll.oleaut32.VariantChangeType
VariantChangeType.restype = ctypes.c_int
VariantChangeType.argtypes = [
    ctypes.c_void_p,  # pvargDest : VARIANT* in/out
    ctypes.c_void_p,  # pvarSrc : VARIANT*
    ctypes.c_ushort,  # wFlags : VAR_CHANGE_FLAGS
    ctypes.c_ushort,  # vt : VARENUM
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('OLEAUT32.dll')
VariantChangeType = Fiddle::Function.new(
  lib['VariantChangeType'],
  [
    Fiddle::TYPE_VOIDP,  # pvargDest : VARIANT* in/out
    Fiddle::TYPE_VOIDP,  # pvarSrc : VARIANT*
    -Fiddle::TYPE_SHORT,  # wFlags : VAR_CHANGE_FLAGS
    -Fiddle::TYPE_SHORT,  # vt : VARENUM
  ],
  Fiddle::TYPE_INT)

#[link(name = "oleaut32")]
extern "system" {
    fn VariantChangeType(
        pvargDest: *mut VARIANT,  // VARIANT* in/out
        pvarSrc: *const VARIANT,  // VARIANT*
        wFlags: u16,  // VAR_CHANGE_FLAGS
        vt: u16  // VARENUM
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("OLEAUT32.dll")]
public static extern int VariantChangeType(IntPtr pvargDest, IntPtr pvarSrc, ushort wFlags, ushort vt);
"@
$api = Add-Type -MemberDefinition $sig -Name 'OLEAUT32_VariantChangeType' -Namespace Win32 -PassThru
# $api::VariantChangeType(pvargDest, pvarSrc, wFlags, vt)

#uselib "OLEAUT32.dll"
#func global VariantChangeType "VariantChangeType" sptr, sptr, sptr, sptr
; VariantChangeType varptr(pvargDest), varptr(pvarSrc), wFlags, vt   ; 戻り値は stat
; pvargDest : VARIANT* in/out -> "sptr"
; pvarSrc : VARIANT* -> "sptr"
; wFlags : VAR_CHANGE_FLAGS -> "sptr"
; vt : VARENUM -> "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 "OLEAUT32.dll"
#cfunc global VariantChangeType "VariantChangeType" var, var, int, int
; res = VariantChangeType(pvargDest, pvarSrc, wFlags, vt)
; pvargDest : VARIANT* in/out -> "var"
; pvarSrc : VARIANT* -> "var"
; wFlags : VAR_CHANGE_FLAGS -> "int"
; vt : VARENUM -> "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 VariantChangeType(VARIANT* pvargDest, VARIANT* pvarSrc, VAR_CHANGE_FLAGS wFlags, VARENUM vt)
#uselib "OLEAUT32.dll"
#cfunc global VariantChangeType "VariantChangeType" var, var, int, int
; res = VariantChangeType(pvargDest, pvarSrc, wFlags, vt)
; pvargDest : VARIANT* in/out -> "var"
; pvarSrc : VARIANT* -> "var"
; wFlags : VAR_CHANGE_FLAGS -> "int"
; vt : VARENUM -> "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 (
	oleaut32 = windows.NewLazySystemDLL("OLEAUT32.dll")
	procVariantChangeType = oleaut32.NewProc("VariantChangeType")
)

// pvargDest (VARIANT* in/out), pvarSrc (VARIANT*), wFlags (VAR_CHANGE_FLAGS), vt (VARENUM)
r1, _, err := procVariantChangeType.Call(
	uintptr(pvargDest),
	uintptr(pvarSrc),
	uintptr(wFlags),
	uintptr(vt),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function VariantChangeType(
  pvargDest: Pointer;   // VARIANT* in/out
  pvarSrc: Pointer;   // VARIANT*
  wFlags: Word;   // VAR_CHANGE_FLAGS
  vt: Word   // VARENUM
): Integer; stdcall;
  external 'OLEAUT32.dll' name 'VariantChangeType';

result := DllCall("OLEAUT32\VariantChangeType"
    , "Ptr", pvargDest   ; VARIANT* in/out
    , "Ptr", pvarSrc   ; VARIANT*
    , "UShort", wFlags   ; VAR_CHANGE_FLAGS
    , "UShort", vt   ; VARENUM
    , "Int")   ; return: HRESULT

●VariantChangeType(pvargDest, pvarSrc, wFlags, vt) = DLL("OLEAUT32.dll", "int VariantChangeType(void*, void*, int, int)")
# 呼び出し: VariantChangeType(pvargDest, pvarSrc, wFlags, vt)
# pvargDest : VARIANT* in/out -> "void*"
# pvarSrc : VARIANT* -> "void*"
# wFlags : VAR_CHANGE_FLAGS -> "int"
# vt : VARENUM -> "int"
# 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)。