VarDecAdd

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

HRESULT VarDecAdd(
    DECIMAL* pdecLeft,
    DECIMAL* pdecRight,
    DECIMAL* pdecResult
);

<DllImport("OLEAUT32.dll", ExactSpelling:=True)>
Public Shared Function VarDecAdd(
    pdecLeft As IntPtr,   ' DECIMAL*
    pdecRight As IntPtr,   ' DECIMAL*
    pdecResult As IntPtr   ' DECIMAL* out
) As Integer
End Function

' pdecLeft : DECIMAL*
' pdecRight : DECIMAL*
' pdecResult : DECIMAL* out
Declare PtrSafe Function VarDecAdd Lib "oleaut32" ( _
    ByVal pdecLeft As LongPtr, _
    ByVal pdecRight As LongPtr, _
    ByVal pdecResult 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

VarDecAdd = ctypes.windll.oleaut32.VarDecAdd
VarDecAdd.restype = ctypes.c_int
VarDecAdd.argtypes = [
    ctypes.c_void_p,  # pdecLeft : DECIMAL*
    ctypes.c_void_p,  # pdecRight : DECIMAL*
    ctypes.c_void_p,  # pdecResult : DECIMAL* out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('OLEAUT32.dll')
VarDecAdd = Fiddle::Function.new(
  lib['VarDecAdd'],
  [
    Fiddle::TYPE_VOIDP,  # pdecLeft : DECIMAL*
    Fiddle::TYPE_VOIDP,  # pdecRight : DECIMAL*
    Fiddle::TYPE_VOIDP,  # pdecResult : DECIMAL* out
  ],
  Fiddle::TYPE_INT)

#[link(name = "oleaut32")]
extern "system" {
    fn VarDecAdd(
        pdecLeft: *mut DECIMAL,  // DECIMAL*
        pdecRight: *mut DECIMAL,  // DECIMAL*
        pdecResult: *mut DECIMAL  // DECIMAL* out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("OLEAUT32.dll")]
public static extern int VarDecAdd(IntPtr pdecLeft, IntPtr pdecRight, IntPtr pdecResult);
"@
$api = Add-Type -MemberDefinition $sig -Name 'OLEAUT32_VarDecAdd' -Namespace Win32 -PassThru
# $api::VarDecAdd(pdecLeft, pdecRight, pdecResult)

#uselib "OLEAUT32.dll"
#func global VarDecAdd "VarDecAdd" sptr, sptr, sptr
; VarDecAdd varptr(pdecLeft), varptr(pdecRight), varptr(pdecResult)   ; 戻り値は stat
; pdecLeft : DECIMAL* -> "sptr"
; pdecRight : DECIMAL* -> "sptr"
; pdecResult : DECIMAL* 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 "OLEAUT32.dll"
#cfunc global VarDecAdd "VarDecAdd" var, var, var
; res = VarDecAdd(pdecLeft, pdecRight, pdecResult)
; pdecLeft : DECIMAL* -> "var"
; pdecRight : DECIMAL* -> "var"
; pdecResult : DECIMAL* 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。

; HRESULT VarDecAdd(DECIMAL* pdecLeft, DECIMAL* pdecRight, DECIMAL* pdecResult)
#uselib "OLEAUT32.dll"
#cfunc global VarDecAdd "VarDecAdd" var, var, var
; res = VarDecAdd(pdecLeft, pdecRight, pdecResult)
; pdecLeft : DECIMAL* -> "var"
; pdecRight : DECIMAL* -> "var"
; pdecResult : DECIMAL* 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 (
	oleaut32 = windows.NewLazySystemDLL("OLEAUT32.dll")
	procVarDecAdd = oleaut32.NewProc("VarDecAdd")
)

// pdecLeft (DECIMAL*), pdecRight (DECIMAL*), pdecResult (DECIMAL* out)
r1, _, err := procVarDecAdd.Call(
	uintptr(pdecLeft),
	uintptr(pdecRight),
	uintptr(pdecResult),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function VarDecAdd(
  pdecLeft: Pointer;   // DECIMAL*
  pdecRight: Pointer;   // DECIMAL*
  pdecResult: Pointer   // DECIMAL* out
): Integer; stdcall;
  external 'OLEAUT32.dll' name 'VarDecAdd';

result := DllCall("OLEAUT32\VarDecAdd"
    , "Ptr", pdecLeft   ; DECIMAL*
    , "Ptr", pdecRight   ; DECIMAL*
    , "Ptr", pdecResult   ; DECIMAL* out
    , "Int")   ; return: HRESULT

●VarDecAdd(pdecLeft, pdecRight, pdecResult) = DLL("OLEAUT32.dll", "int VarDecAdd(void*, void*, void*)")
# 呼び出し: VarDecAdd(pdecLeft, pdecRight, pdecResult)
# pdecLeft : DECIMAL* -> "void*"
# pdecRight : DECIMAL* -> "void*"
# pdecResult : DECIMAL* 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)。