EngMultiByteToWideChar

// GDI32.dll
#include <windows.h>

INT EngMultiByteToWideChar(
    DWORD CodePage,
    LPWSTR WideCharString,   // optional
    INT BytesInWideCharString,
    LPSTR MultiByteString,   // optional
    INT BytesInMultiByteString
);

<DllImport("GDI32.dll", ExactSpelling:=True)>
Public Shared Function EngMultiByteToWideChar(
    CodePage As UInteger,   ' DWORD
    <MarshalAs(UnmanagedType.LPWStr)> WideCharString As System.Text.StringBuilder,   ' LPWSTR optional, out
    BytesInWideCharString As Integer,   ' INT
    <MarshalAs(UnmanagedType.LPStr)> MultiByteString As String,   ' LPSTR optional
    BytesInMultiByteString As Integer   ' INT
) As Integer
End Function

' CodePage : DWORD
' WideCharString : LPWSTR optional, out
' BytesInWideCharString : INT
' MultiByteString : LPSTR optional
' BytesInMultiByteString : INT
Declare PtrSafe Function EngMultiByteToWideChar Lib "gdi32" ( _
    ByVal CodePage As Long, _
    ByVal WideCharString As LongPtr, _
    ByVal BytesInWideCharString As Long, _
    ByVal MultiByteString As String, _
    ByVal BytesInMultiByteString 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

EngMultiByteToWideChar = ctypes.windll.gdi32.EngMultiByteToWideChar
EngMultiByteToWideChar.restype = ctypes.c_int
EngMultiByteToWideChar.argtypes = [
    wintypes.DWORD,  # CodePage : DWORD
    wintypes.LPWSTR,  # WideCharString : LPWSTR optional, out
    ctypes.c_int,  # BytesInWideCharString : INT
    wintypes.LPCSTR,  # MultiByteString : LPSTR optional
    ctypes.c_int,  # BytesInMultiByteString : INT
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('GDI32.dll')
EngMultiByteToWideChar = Fiddle::Function.new(
  lib['EngMultiByteToWideChar'],
  [
    -Fiddle::TYPE_INT,  # CodePage : DWORD
    Fiddle::TYPE_VOIDP,  # WideCharString : LPWSTR optional, out
    Fiddle::TYPE_INT,  # BytesInWideCharString : INT
    Fiddle::TYPE_VOIDP,  # MultiByteString : LPSTR optional
    Fiddle::TYPE_INT,  # BytesInMultiByteString : INT
  ],
  Fiddle::TYPE_INT)

#[link(name = "gdi32")]
extern "system" {
    fn EngMultiByteToWideChar(
        CodePage: u32,  // DWORD
        WideCharString: *mut u16,  // LPWSTR optional, out
        BytesInWideCharString: i32,  // INT
        MultiByteString: *mut u8,  // LPSTR optional
        BytesInMultiByteString: i32  // INT
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("GDI32.dll")]
public static extern int EngMultiByteToWideChar(uint CodePage, [MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder WideCharString, int BytesInWideCharString, [MarshalAs(UnmanagedType.LPStr)] string MultiByteString, int BytesInMultiByteString);
"@
$api = Add-Type -MemberDefinition $sig -Name 'GDI32_EngMultiByteToWideChar' -Namespace Win32 -PassThru
# $api::EngMultiByteToWideChar(CodePage, WideCharString, BytesInWideCharString, MultiByteString, BytesInMultiByteString)

#uselib "GDI32.dll"
#func global EngMultiByteToWideChar "EngMultiByteToWideChar" sptr, sptr, sptr, sptr, sptr
; EngMultiByteToWideChar CodePage, varptr(WideCharString), BytesInWideCharString, MultiByteString, BytesInMultiByteString   ; 戻り値は stat
; CodePage : DWORD -> "sptr"
; WideCharString : LPWSTR optional, out -> "sptr"
; BytesInWideCharString : INT -> "sptr"
; MultiByteString : LPSTR optional -> "sptr"
; BytesInMultiByteString : INT -> "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 "GDI32.dll"
#cfunc global EngMultiByteToWideChar "EngMultiByteToWideChar" int, var, int, str, int
; res = EngMultiByteToWideChar(CodePage, WideCharString, BytesInWideCharString, MultiByteString, BytesInMultiByteString)
; CodePage : DWORD -> "int"
; WideCharString : LPWSTR optional, out -> "var"
; BytesInWideCharString : INT -> "int"
; MultiByteString : LPSTR optional -> "str"
; BytesInMultiByteString : INT -> "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。

; INT EngMultiByteToWideChar(DWORD CodePage, LPWSTR WideCharString, INT BytesInWideCharString, LPSTR MultiByteString, INT BytesInMultiByteString)
#uselib "GDI32.dll"
#cfunc global EngMultiByteToWideChar "EngMultiByteToWideChar" int, var, int, str, int
; res = EngMultiByteToWideChar(CodePage, WideCharString, BytesInWideCharString, MultiByteString, BytesInMultiByteString)
; CodePage : DWORD -> "int"
; WideCharString : LPWSTR optional, out -> "var"
; BytesInWideCharString : INT -> "int"
; MultiByteString : LPSTR optional -> "str"
; BytesInMultiByteString : INT -> "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 (
	gdi32 = windows.NewLazySystemDLL("GDI32.dll")
	procEngMultiByteToWideChar = gdi32.NewProc("EngMultiByteToWideChar")
)

// CodePage (DWORD), WideCharString (LPWSTR optional, out), BytesInWideCharString (INT), MultiByteString (LPSTR optional), BytesInMultiByteString (INT)
r1, _, err := procEngMultiByteToWideChar.Call(
	uintptr(CodePage),
	uintptr(WideCharString),
	uintptr(BytesInWideCharString),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(MultiByteString))),
	uintptr(BytesInMultiByteString),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function EngMultiByteToWideChar(
  CodePage: DWORD;   // DWORD
  WideCharString: PWideChar;   // LPWSTR optional, out
  BytesInWideCharString: Integer;   // INT
  MultiByteString: PAnsiChar;   // LPSTR optional
  BytesInMultiByteString: Integer   // INT
): Integer; stdcall;
  external 'GDI32.dll' name 'EngMultiByteToWideChar';

result := DllCall("GDI32\EngMultiByteToWideChar"
    , "UInt", CodePage   ; DWORD
    , "Ptr", WideCharString   ; LPWSTR optional, out
    , "Int", BytesInWideCharString   ; INT
    , "AStr", MultiByteString   ; LPSTR optional
    , "Int", BytesInMultiByteString   ; INT
    , "Int")   ; return: INT

●EngMultiByteToWideChar(CodePage, WideCharString, BytesInWideCharString, MultiByteString, BytesInMultiByteString) = DLL("GDI32.dll", "int EngMultiByteToWideChar(dword, char*, int, char*, int)")
# 呼び出し: EngMultiByteToWideChar(CodePage, WideCharString, BytesInWideCharString, MultiByteString, BytesInMultiByteString)
# CodePage : DWORD -> "dword"
# WideCharString : LPWSTR optional, out -> "char*"
# BytesInWideCharString : INT -> "int"
# MultiByteString : LPSTR optional -> "char*"
# BytesInMultiByteString : INT -> "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)。