VarR8Round

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

HRESULT VarR8Round(
    DOUBLE dblIn,
    INT cDecimals,
    DOUBLE* pdblResult
);

<DllImport("OLEAUT32.dll", ExactSpelling:=True)>
Public Shared Function VarR8Round(
    dblIn As Double,   ' DOUBLE
    cDecimals As Integer,   ' INT
    <Out> ByRef pdblResult As Double   ' DOUBLE* out
) As Integer
End Function

' dblIn : DOUBLE
' cDecimals : INT
' pdblResult : DOUBLE* out
Declare PtrSafe Function VarR8Round Lib "oleaut32" ( _
    ByVal dblIn As Double, _
    ByVal cDecimals As Long, _
    ByRef pdblResult As Double) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

VarR8Round = ctypes.windll.oleaut32.VarR8Round
VarR8Round.restype = ctypes.c_int
VarR8Round.argtypes = [
    ctypes.c_double,  # dblIn : DOUBLE
    ctypes.c_int,  # cDecimals : INT
    ctypes.POINTER(ctypes.c_double),  # pdblResult : DOUBLE* out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('OLEAUT32.dll')
VarR8Round = Fiddle::Function.new(
  lib['VarR8Round'],
  [
    Fiddle::TYPE_DOUBLE,  # dblIn : DOUBLE
    Fiddle::TYPE_INT,  # cDecimals : INT
    Fiddle::TYPE_VOIDP,  # pdblResult : DOUBLE* out
  ],
  Fiddle::TYPE_INT)

#[link(name = "oleaut32")]
extern "system" {
    fn VarR8Round(
        dblIn: f64,  // DOUBLE
        cDecimals: i32,  // INT
        pdblResult: *mut f64  // DOUBLE* out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("OLEAUT32.dll")]
public static extern int VarR8Round(double dblIn, int cDecimals, out double pdblResult);
"@
$api = Add-Type -MemberDefinition $sig -Name 'OLEAUT32_VarR8Round' -Namespace Win32 -PassThru
# $api::VarR8Round(dblIn, cDecimals, pdblResult)

#uselib "OLEAUT32.dll"
#func global VarR8Round "VarR8Round" double, sptr, sptr
; VarR8Round dblIn, cDecimals, varptr(pdblResult)   ; 戻り値は stat
; dblIn : DOUBLE -> "double"
; cDecimals : INT -> "sptr"
; pdblResult : DOUBLE* 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 VarR8Round "VarR8Round" double, int, var
; res = VarR8Round(dblIn, cDecimals, pdblResult)
; dblIn : DOUBLE -> "double"
; cDecimals : INT -> "int"
; pdblResult : DOUBLE* 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 VarR8Round(DOUBLE dblIn, INT cDecimals, DOUBLE* pdblResult)
#uselib "OLEAUT32.dll"
#cfunc global VarR8Round "VarR8Round" double, int, var
; res = VarR8Round(dblIn, cDecimals, pdblResult)
; dblIn : DOUBLE -> "double"
; cDecimals : INT -> "int"
; pdblResult : DOUBLE* 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 (
	"math"
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	oleaut32 = windows.NewLazySystemDLL("OLEAUT32.dll")
	procVarR8Round = oleaut32.NewProc("VarR8Round")
)

// dblIn (DOUBLE), cDecimals (INT), pdblResult (DOUBLE* out)
r1, _, err := procVarR8Round.Call(
	uintptr(math.Float64bits(dblIn)),
	uintptr(cDecimals),
	uintptr(pdblResult),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT
// 注意: float/double 引数は proc.Call では XMM レジスタに渡せません。
// windows.SyscallN(proc.Addr(), math.Float64bits(x), ...) もしくは cgo を使用してください。

function VarR8Round(
  dblIn: Double;   // DOUBLE
  cDecimals: Integer;   // INT
  pdblResult: Pointer   // DOUBLE* out
): Integer; stdcall;
  external 'OLEAUT32.dll' name 'VarR8Round';

result := DllCall("OLEAUT32\VarR8Round"
    , "Double", dblIn   ; DOUBLE
    , "Int", cDecimals   ; INT
    , "Ptr", pdblResult   ; DOUBLE* out
    , "Int")   ; return: HRESULT

●VarR8Round(dblIn, cDecimals, pdblResult) = DLL("OLEAUT32.dll", "int VarR8Round(double, int, void*)")
# 呼び出し: VarR8Round(dblIn, cDecimals, pdblResult)
# dblIn : DOUBLE -> "double"
# cDecimals : INT -> "int"
# pdblResult : DOUBLE* 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)。