IdentifyMIMEType

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

HRESULT IdentifyMIMEType(
    const BYTE* pbBytes,
    DWORD nBytes,
    DWORD* pnFormat
);

<DllImport("ImgUtil.dll", ExactSpelling:=True)>
Public Shared Function IdentifyMIMEType(
    pbBytes As IntPtr,   ' BYTE*
    nBytes As UInteger,   ' DWORD
    ByRef pnFormat As UInteger   ' DWORD* in/out
) As Integer
End Function

' pbBytes : BYTE*
' nBytes : DWORD
' pnFormat : DWORD* in/out
Declare PtrSafe Function IdentifyMIMEType Lib "imgutil" ( _
    ByVal pbBytes As LongPtr, _
    ByVal nBytes As Long, _
    ByRef pnFormat 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

IdentifyMIMEType = ctypes.windll.imgutil.IdentifyMIMEType
IdentifyMIMEType.restype = ctypes.c_int
IdentifyMIMEType.argtypes = [
    ctypes.POINTER(ctypes.c_ubyte),  # pbBytes : BYTE*
    wintypes.DWORD,  # nBytes : DWORD
    ctypes.POINTER(wintypes.DWORD),  # pnFormat : DWORD* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('ImgUtil.dll')
IdentifyMIMEType = Fiddle::Function.new(
  lib['IdentifyMIMEType'],
  [
    Fiddle::TYPE_VOIDP,  # pbBytes : BYTE*
    -Fiddle::TYPE_INT,  # nBytes : DWORD
    Fiddle::TYPE_VOIDP,  # pnFormat : DWORD* in/out
  ],
  Fiddle::TYPE_INT)

#[link(name = "imgutil")]
extern "system" {
    fn IdentifyMIMEType(
        pbBytes: *const u8,  // BYTE*
        nBytes: u32,  // DWORD
        pnFormat: *mut u32  // DWORD* in/out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("ImgUtil.dll")]
public static extern int IdentifyMIMEType(IntPtr pbBytes, uint nBytes, ref uint pnFormat);
"@
$api = Add-Type -MemberDefinition $sig -Name 'ImgUtil_IdentifyMIMEType' -Namespace Win32 -PassThru
# $api::IdentifyMIMEType(pbBytes, nBytes, pnFormat)

#uselib "ImgUtil.dll"
#func global IdentifyMIMEType "IdentifyMIMEType" sptr, sptr, sptr
; IdentifyMIMEType varptr(pbBytes), nBytes, varptr(pnFormat)   ; 戻り値は stat
; pbBytes : BYTE* -> "sptr"
; nBytes : DWORD -> "sptr"
; pnFormat : DWORD* in/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 "ImgUtil.dll"
#cfunc global IdentifyMIMEType "IdentifyMIMEType" var, int, var
; res = IdentifyMIMEType(pbBytes, nBytes, pnFormat)
; pbBytes : BYTE* -> "var"
; nBytes : DWORD -> "int"
; pnFormat : DWORD* in/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 IdentifyMIMEType(BYTE* pbBytes, DWORD nBytes, DWORD* pnFormat)
#uselib "ImgUtil.dll"
#cfunc global IdentifyMIMEType "IdentifyMIMEType" var, int, var
; res = IdentifyMIMEType(pbBytes, nBytes, pnFormat)
; pbBytes : BYTE* -> "var"
; nBytes : DWORD -> "int"
; pnFormat : DWORD* in/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 (
	imgutil = windows.NewLazySystemDLL("ImgUtil.dll")
	procIdentifyMIMEType = imgutil.NewProc("IdentifyMIMEType")
)

// pbBytes (BYTE*), nBytes (DWORD), pnFormat (DWORD* in/out)
r1, _, err := procIdentifyMIMEType.Call(
	uintptr(pbBytes),
	uintptr(nBytes),
	uintptr(pnFormat),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function IdentifyMIMEType(
  pbBytes: Pointer;   // BYTE*
  nBytes: DWORD;   // DWORD
  pnFormat: Pointer   // DWORD* in/out
): Integer; stdcall;
  external 'ImgUtil.dll' name 'IdentifyMIMEType';

result := DllCall("ImgUtil\IdentifyMIMEType"
    , "Ptr", pbBytes   ; BYTE*
    , "UInt", nBytes   ; DWORD
    , "Ptr", pnFormat   ; DWORD* in/out
    , "Int")   ; return: HRESULT

●IdentifyMIMEType(pbBytes, nBytes, pnFormat) = DLL("ImgUtil.dll", "int IdentifyMIMEType(void*, dword, void*)")
# 呼び出し: IdentifyMIMEType(pbBytes, nBytes, pnFormat)
# pbBytes : BYTE* -> "void*"
# nBytes : DWORD -> "dword"
# pnFormat : DWORD* in/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)。