DecodeImageEx

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

HRESULT DecodeImageEx(
    IStream* pStream,
    IMapMIMEToCLSID* pMap,
    IUnknown* pEventSink,
    LPCWSTR pszMIMETypeParam
);

<DllImport("ImgUtil.dll", ExactSpelling:=True)>
Public Shared Function DecodeImageEx(
    pStream As IntPtr,   ' IStream*
    pMap As IntPtr,   ' IMapMIMEToCLSID*
    pEventSink As IntPtr,   ' IUnknown*
    <MarshalAs(UnmanagedType.LPWStr)> pszMIMETypeParam As String   ' LPCWSTR
) As Integer
End Function

' pStream : IStream*
' pMap : IMapMIMEToCLSID*
' pEventSink : IUnknown*
' pszMIMETypeParam : LPCWSTR
Declare PtrSafe Function DecodeImageEx Lib "imgutil" ( _
    ByVal pStream As LongPtr, _
    ByVal pMap As LongPtr, _
    ByVal pEventSink As LongPtr, _
    ByVal pszMIMETypeParam 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

DecodeImageEx = ctypes.windll.imgutil.DecodeImageEx
DecodeImageEx.restype = ctypes.c_int
DecodeImageEx.argtypes = [
    ctypes.c_void_p,  # pStream : IStream*
    ctypes.c_void_p,  # pMap : IMapMIMEToCLSID*
    ctypes.c_void_p,  # pEventSink : IUnknown*
    wintypes.LPCWSTR,  # pszMIMETypeParam : LPCWSTR
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('ImgUtil.dll')
DecodeImageEx = Fiddle::Function.new(
  lib['DecodeImageEx'],
  [
    Fiddle::TYPE_VOIDP,  # pStream : IStream*
    Fiddle::TYPE_VOIDP,  # pMap : IMapMIMEToCLSID*
    Fiddle::TYPE_VOIDP,  # pEventSink : IUnknown*
    Fiddle::TYPE_VOIDP,  # pszMIMETypeParam : LPCWSTR
  ],
  Fiddle::TYPE_INT)

#[link(name = "imgutil")]
extern "system" {
    fn DecodeImageEx(
        pStream: *mut core::ffi::c_void,  // IStream*
        pMap: *mut core::ffi::c_void,  // IMapMIMEToCLSID*
        pEventSink: *mut core::ffi::c_void,  // IUnknown*
        pszMIMETypeParam: *const u16  // LPCWSTR
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("ImgUtil.dll")]
public static extern int DecodeImageEx(IntPtr pStream, IntPtr pMap, IntPtr pEventSink, [MarshalAs(UnmanagedType.LPWStr)] string pszMIMETypeParam);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ImgUtil_DecodeImageEx' -Namespace Win32 -PassThru
# $api::DecodeImageEx(pStream, pMap, pEventSink, pszMIMETypeParam)

#uselib "ImgUtil.dll"
#func global DecodeImageEx "DecodeImageEx" sptr, sptr, sptr, sptr
; DecodeImageEx pStream, pMap, pEventSink, pszMIMETypeParam   ; 戻り値は stat
; pStream : IStream* -> "sptr"
; pMap : IMapMIMEToCLSID* -> "sptr"
; pEventSink : IUnknown* -> "sptr"
; pszMIMETypeParam : LPCWSTR -> "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 "ImgUtil.dll"
#cfunc global DecodeImageEx "DecodeImageEx" sptr, sptr, sptr, wstr
; res = DecodeImageEx(pStream, pMap, pEventSink, pszMIMETypeParam)
; pStream : IStream* -> "sptr"
; pMap : IMapMIMEToCLSID* -> "sptr"
; pEventSink : IUnknown* -> "sptr"
; pszMIMETypeParam : LPCWSTR -> "wstr"

; HRESULT DecodeImageEx(IStream* pStream, IMapMIMEToCLSID* pMap, IUnknown* pEventSink, LPCWSTR pszMIMETypeParam)
#uselib "ImgUtil.dll"
#cfunc global DecodeImageEx "DecodeImageEx" intptr, intptr, intptr, wstr
; res = DecodeImageEx(pStream, pMap, pEventSink, pszMIMETypeParam)
; pStream : IStream* -> "intptr"
; pMap : IMapMIMEToCLSID* -> "intptr"
; pEventSink : IUnknown* -> "intptr"
; pszMIMETypeParam : LPCWSTR -> "wstr"

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	imgutil = windows.NewLazySystemDLL("ImgUtil.dll")
	procDecodeImageEx = imgutil.NewProc("DecodeImageEx")
)

// pStream (IStream*), pMap (IMapMIMEToCLSID*), pEventSink (IUnknown*), pszMIMETypeParam (LPCWSTR)
r1, _, err := procDecodeImageEx.Call(
	uintptr(pStream),
	uintptr(pMap),
	uintptr(pEventSink),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(pszMIMETypeParam))),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function DecodeImageEx(
  pStream: Pointer;   // IStream*
  pMap: Pointer;   // IMapMIMEToCLSID*
  pEventSink: Pointer;   // IUnknown*
  pszMIMETypeParam: PWideChar   // LPCWSTR
): Integer; stdcall;
  external 'ImgUtil.dll' name 'DecodeImageEx';

result := DllCall("ImgUtil\DecodeImageEx"
    , "Ptr", pStream   ; IStream*
    , "Ptr", pMap   ; IMapMIMEToCLSID*
    , "Ptr", pEventSink   ; IUnknown*
    , "WStr", pszMIMETypeParam   ; LPCWSTR
    , "Int")   ; return: HRESULT

●DecodeImageEx(pStream, pMap, pEventSink, pszMIMETypeParam) = DLL("ImgUtil.dll", "int DecodeImageEx(void*, void*, void*, char*)")
# 呼び出し: DecodeImageEx(pStream, pMap, pEventSink, pszMIMETypeParam)
# pStream : IStream* -> "void*"
# pMap : IMapMIMEToCLSID* -> "void*"
# pEventSink : IUnknown* -> "void*"
# pszMIMETypeParam : LPCWSTR -> "char*"
# 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)。