inet_ntop

// WS2_32.dll
#include <windows.h>

LPSTR inet_ntop(
    INT Family,
    const void* pAddr,
    LPSTR pStringBuf,
    UINT_PTR StringBufSize
);

<DllImport("WS2_32.dll", SetLastError:=True, ExactSpelling:=True)>
Public Shared Function inet_ntop(
    Family As Integer,   ' INT
    pAddr As IntPtr,   ' void*
    <MarshalAs(UnmanagedType.LPStr)> pStringBuf As System.Text.StringBuilder,   ' LPSTR out
    StringBufSize As UIntPtr   ' UINT_PTR
) As IntPtr
End Function

' Family : INT
' pAddr : void*
' pStringBuf : LPSTR out
' StringBufSize : UINT_PTR
Declare PtrSafe Function inet_ntop Lib "ws2_32" ( _
    ByVal Family As Long, _
    ByVal pAddr As LongPtr, _
    ByVal pStringBuf As String, _
    ByVal StringBufSize As LongPtr) As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

inet_ntop = ctypes.windll.ws2_32.inet_ntop
inet_ntop.restype = wintypes.LPSTR
inet_ntop.argtypes = [
    ctypes.c_int,  # Family : INT
    ctypes.POINTER(None),  # pAddr : void*
    wintypes.LPSTR,  # pStringBuf : LPSTR out
    ctypes.c_size_t,  # StringBufSize : UINT_PTR
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('WS2_32.dll')
inet_ntop = Fiddle::Function.new(
  lib['inet_ntop'],
  [
    Fiddle::TYPE_INT,  # Family : INT
    Fiddle::TYPE_VOIDP,  # pAddr : void*
    Fiddle::TYPE_VOIDP,  # pStringBuf : LPSTR out
    Fiddle::TYPE_UINTPTR_T,  # StringBufSize : UINT_PTR
  ],
  Fiddle::TYPE_VOIDP)

#[link(name = "ws2_32")]
extern "system" {
    fn inet_ntop(
        Family: i32,  // INT
        pAddr: *const (),  // void*
        pStringBuf: *mut u8,  // LPSTR out
        StringBufSize: usize  // UINT_PTR
    ) -> *mut u8;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("WS2_32.dll", SetLastError = true)]
public static extern IntPtr inet_ntop(int Family, IntPtr pAddr, [MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder pStringBuf, UIntPtr StringBufSize);
"@
$api = Add-Type -MemberDefinition $sig -Name 'WS2_32_inet_ntop' -Namespace Win32 -PassThru
# $api::inet_ntop(Family, pAddr, pStringBuf, StringBufSize)

#uselib "WS2_32.dll"
#func global inet_ntop "inet_ntop" sptr, sptr, sptr, sptr
; inet_ntop Family, pAddr, varptr(pStringBuf), StringBufSize   ; 戻り値は stat
; Family : INT -> "sptr"
; pAddr : void* -> "sptr"
; pStringBuf : LPSTR out -> "sptr"
; StringBufSize : UINT_PTR -> "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 "WS2_32.dll"
#cfunc global inet_ntop "inet_ntop" int, sptr, var, sptr
; res = inet_ntop(Family, pAddr, pStringBuf, StringBufSize)
; Family : INT -> "int"
; pAddr : void* -> "sptr"
; pStringBuf : LPSTR out -> "var"
; StringBufSize : UINT_PTR -> "sptr"
; ※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 inet_ntop(INT Family, void* pAddr, LPSTR pStringBuf, UINT_PTR StringBufSize)
#uselib "WS2_32.dll"
#cfunc global inet_ntop "inet_ntop" int, intptr, var, intptr
; res = inet_ntop(Family, pAddr, pStringBuf, StringBufSize)
; Family : INT -> "int"
; pAddr : void* -> "intptr"
; pStringBuf : LPSTR out -> "var"
; StringBufSize : UINT_PTR -> "intptr"
; ※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 (
	ws2_32 = windows.NewLazySystemDLL("WS2_32.dll")
	procinet_ntop = ws2_32.NewProc("inet_ntop")
)

// Family (INT), pAddr (void*), pStringBuf (LPSTR out), StringBufSize (UINT_PTR)
r1, _, err := procinet_ntop.Call(
	uintptr(Family),
	uintptr(pAddr),
	uintptr(pStringBuf),
	uintptr(StringBufSize),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // LPSTR

function inet_ntop(
  Family: Integer;   // INT
  pAddr: Pointer;   // void*
  pStringBuf: PAnsiChar;   // LPSTR out
  StringBufSize: NativeUInt   // UINT_PTR
): PAnsiChar; stdcall;
  external 'WS2_32.dll' name 'inet_ntop';

result := DllCall("WS2_32\inet_ntop"
    , "Int", Family   ; INT
    , "Ptr", pAddr   ; void*
    , "Ptr", pStringBuf   ; LPSTR out
    , "UPtr", StringBufSize   ; UINT_PTR
    , "Ptr")   ; return: LPSTR

●inet_ntop(Family, pAddr, pStringBuf, StringBufSize) = DLL("WS2_32.dll", "char* inet_ntop(int, void*, char*, int)")
# 呼び出し: inet_ntop(Family, pAddr, pStringBuf, StringBufSize)
# Family : INT -> "int"
# pAddr : void* -> "void*"
# pStringBuf : LPSTR out -> "char*"
# StringBufSize : UINT_PTR -> "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)。