ucnv_detectUnicodeSignature

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

LPSTR ucnv_detectUnicodeSignature(
    LPCSTR source,
    INT sourceLength,
    INT* signatureLength,
    UErrorCode* pErrorCode
);

<DllImport("icuuc.dll", ExactSpelling:=True, CallingConvention:=CallingConvention.Cdecl)>
Public Shared Function ucnv_detectUnicodeSignature(
    <MarshalAs(UnmanagedType.LPStr)> source As String,   ' LPCSTR
    sourceLength As Integer,   ' INT
    ByRef signatureLength As Integer,   ' INT* in/out
    ByRef pErrorCode As Integer   ' UErrorCode* in/out
) As IntPtr
End Function

' source : LPCSTR
' sourceLength : INT
' signatureLength : INT* in/out
' pErrorCode : UErrorCode* in/out
Declare PtrSafe Function ucnv_detectUnicodeSignature Lib "icuuc" ( _
    ByVal source As String, _
    ByVal sourceLength As Long, _
    ByRef signatureLength As Long, _
    ByRef pErrorCode As Long) As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

ucnv_detectUnicodeSignature = ctypes.cdll.icuuc.ucnv_detectUnicodeSignature
ucnv_detectUnicodeSignature.restype = wintypes.LPSTR
ucnv_detectUnicodeSignature.argtypes = [
    wintypes.LPCSTR,  # source : LPCSTR
    ctypes.c_int,  # sourceLength : INT
    ctypes.POINTER(ctypes.c_int),  # signatureLength : INT* in/out
    ctypes.c_void_p,  # pErrorCode : UErrorCode* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('icuuc.dll')
ucnv_detectUnicodeSignature = Fiddle::Function.new(
  lib['ucnv_detectUnicodeSignature'],
  [
    Fiddle::TYPE_VOIDP,  # source : LPCSTR
    Fiddle::TYPE_INT,  # sourceLength : INT
    Fiddle::TYPE_VOIDP,  # signatureLength : INT* in/out
    Fiddle::TYPE_VOIDP,  # pErrorCode : UErrorCode* in/out
  ],
  Fiddle::TYPE_VOIDP, Fiddle::Function::CDECL)

#[link(name = "icuuc")]
extern "C" {
    fn ucnv_detectUnicodeSignature(
        source: *const u8,  // LPCSTR
        sourceLength: i32,  // INT
        signatureLength: *mut i32,  // INT* in/out
        pErrorCode: *mut i32  // UErrorCode* in/out
    ) -> *mut u8;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("icuuc.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern IntPtr ucnv_detectUnicodeSignature([MarshalAs(UnmanagedType.LPStr)] string source, int sourceLength, ref int signatureLength, ref int pErrorCode);
"@
$api = Add-Type -MemberDefinition $sig -Name 'icuuc_ucnv_detectUnicodeSignature' -Namespace Win32 -PassThru
# $api::ucnv_detectUnicodeSignature(source, sourceLength, signatureLength, pErrorCode)

#uselib "icuuc.dll"
#func global ucnv_detectUnicodeSignature "ucnv_detectUnicodeSignature" sptr, sptr, sptr, sptr
; ucnv_detectUnicodeSignature source, sourceLength, varptr(signatureLength), pErrorCode   ; 戻り値は stat
; source : LPCSTR -> "sptr"
; sourceLength : INT -> "sptr"
; signatureLength : INT* in/out -> "sptr"
; pErrorCode : UErrorCode* 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 "icuuc.dll"
#cfunc global ucnv_detectUnicodeSignature "ucnv_detectUnicodeSignature" str, int, var, int
; res = ucnv_detectUnicodeSignature(source, sourceLength, signatureLength, pErrorCode)
; source : LPCSTR -> "str"
; sourceLength : INT -> "int"
; signatureLength : INT* in/out -> "var"
; pErrorCode : UErrorCode* in/out -> "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。

; LPSTR ucnv_detectUnicodeSignature(LPCSTR source, INT sourceLength, INT* signatureLength, UErrorCode* pErrorCode)
#uselib "icuuc.dll"
#cfunc global ucnv_detectUnicodeSignature "ucnv_detectUnicodeSignature" str, int, var, int
; res = ucnv_detectUnicodeSignature(source, sourceLength, signatureLength, pErrorCode)
; source : LPCSTR -> "str"
; sourceLength : INT -> "int"
; signatureLength : INT* in/out -> "var"
; pErrorCode : UErrorCode* in/out -> "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 (
	icuuc = windows.NewLazySystemDLL("icuuc.dll")
	procucnv_detectUnicodeSignature = icuuc.NewProc("ucnv_detectUnicodeSignature")
)

// source (LPCSTR), sourceLength (INT), signatureLength (INT* in/out), pErrorCode (UErrorCode* in/out)
r1, _, err := procucnv_detectUnicodeSignature.Call(
	uintptr(unsafe.Pointer(windows.BytePtrFromString(source))),
	uintptr(sourceLength),
	uintptr(signatureLength),
	uintptr(pErrorCode),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // LPSTR

function ucnv_detectUnicodeSignature(
  source: PAnsiChar;   // LPCSTR
  sourceLength: Integer;   // INT
  signatureLength: Pointer;   // INT* in/out
  pErrorCode: Pointer   // UErrorCode* in/out
): PAnsiChar; cdecl;
  external 'icuuc.dll' name 'ucnv_detectUnicodeSignature';

result := DllCall("icuuc\ucnv_detectUnicodeSignature"
    , "AStr", source   ; LPCSTR
    , "Int", sourceLength   ; INT
    , "Ptr", signatureLength   ; INT* in/out
    , "Ptr", pErrorCode   ; UErrorCode* in/out
    , "Cdecl Ptr")   ; return: LPSTR

●ucnv_detectUnicodeSignature(source, sourceLength, signatureLength, pErrorCode) = DLL("icuuc.dll", "char* ucnv_detectUnicodeSignature(char*, int, void*, void*)")
# 呼び出し: ucnv_detectUnicodeSignature(source, sourceLength, signatureLength, pErrorCode)
# source : LPCSTR -> "char*"
# sourceLength : INT -> "int"
# signatureLength : INT* in/out -> "void*"
# pErrorCode : UErrorCode* 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)。
# ※cdecl関数。DLL()宣言はstdcall前提。cdeclは EXEC_PTR(`cdecl`,…) を使用。