GetIpErrorString

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

DWORD GetIpErrorString(
    DWORD ErrorCode,
    LPWSTR Buffer,   // optional
    DWORD* Size
);

<DllImport("IPHLPAPI.dll", ExactSpelling:=True)>
Public Shared Function GetIpErrorString(
    ErrorCode As UInteger,   ' DWORD
    <MarshalAs(UnmanagedType.LPWStr)> Buffer As System.Text.StringBuilder,   ' LPWSTR optional, out
    ByRef Size As UInteger   ' DWORD* in/out
) As UInteger
End Function

' ErrorCode : DWORD
' Buffer : LPWSTR optional, out
' Size : DWORD* in/out
Declare PtrSafe Function GetIpErrorString Lib "iphlpapi" ( _
    ByVal ErrorCode As Long, _
    ByVal Buffer As LongPtr, _
    ByRef Size 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

GetIpErrorString = ctypes.windll.iphlpapi.GetIpErrorString
GetIpErrorString.restype = wintypes.DWORD
GetIpErrorString.argtypes = [
    wintypes.DWORD,  # ErrorCode : DWORD
    wintypes.LPWSTR,  # Buffer : LPWSTR optional, out
    ctypes.POINTER(wintypes.DWORD),  # Size : DWORD* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('IPHLPAPI.dll')
GetIpErrorString = Fiddle::Function.new(
  lib['GetIpErrorString'],
  [
    -Fiddle::TYPE_INT,  # ErrorCode : DWORD
    Fiddle::TYPE_VOIDP,  # Buffer : LPWSTR optional, out
    Fiddle::TYPE_VOIDP,  # Size : DWORD* in/out
  ],
  -Fiddle::TYPE_INT)

#[link(name = "iphlpapi")]
extern "system" {
    fn GetIpErrorString(
        ErrorCode: u32,  // DWORD
        Buffer: *mut u16,  // LPWSTR optional, out
        Size: *mut u32  // DWORD* in/out
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("IPHLPAPI.dll")]
public static extern uint GetIpErrorString(uint ErrorCode, [MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder Buffer, ref uint Size);
"@
$api = Add-Type -MemberDefinition $sig -Name 'IPHLPAPI_GetIpErrorString' -Namespace Win32 -PassThru
# $api::GetIpErrorString(ErrorCode, Buffer, Size)

#uselib "IPHLPAPI.dll"
#func global GetIpErrorString "GetIpErrorString" sptr, sptr, sptr
; GetIpErrorString ErrorCode, varptr(Buffer), varptr(Size)   ; 戻り値は stat
; ErrorCode : DWORD -> "sptr"
; Buffer : LPWSTR optional, out -> "sptr"
; Size : 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 "IPHLPAPI.dll"
#cfunc global GetIpErrorString "GetIpErrorString" int, var, var
; res = GetIpErrorString(ErrorCode, Buffer, Size)
; ErrorCode : DWORD -> "int"
; Buffer : LPWSTR optional, out -> "var"
; Size : 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。

; DWORD GetIpErrorString(DWORD ErrorCode, LPWSTR Buffer, DWORD* Size)
#uselib "IPHLPAPI.dll"
#cfunc global GetIpErrorString "GetIpErrorString" int, var, var
; res = GetIpErrorString(ErrorCode, Buffer, Size)
; ErrorCode : DWORD -> "int"
; Buffer : LPWSTR optional, out -> "var"
; Size : 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 (
	iphlpapi = windows.NewLazySystemDLL("IPHLPAPI.dll")
	procGetIpErrorString = iphlpapi.NewProc("GetIpErrorString")
)

// ErrorCode (DWORD), Buffer (LPWSTR optional, out), Size (DWORD* in/out)
r1, _, err := procGetIpErrorString.Call(
	uintptr(ErrorCode),
	uintptr(Buffer),
	uintptr(Size),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function GetIpErrorString(
  ErrorCode: DWORD;   // DWORD
  Buffer: PWideChar;   // LPWSTR optional, out
  Size: Pointer   // DWORD* in/out
): DWORD; stdcall;
  external 'IPHLPAPI.dll' name 'GetIpErrorString';

result := DllCall("IPHLPAPI\GetIpErrorString"
    , "UInt", ErrorCode   ; DWORD
    , "Ptr", Buffer   ; LPWSTR optional, out
    , "Ptr", Size   ; DWORD* in/out
    , "UInt")   ; return: DWORD

●GetIpErrorString(ErrorCode, Buffer, Size) = DLL("IPHLPAPI.dll", "dword GetIpErrorString(dword, char*, void*)")
# 呼び出し: GetIpErrorString(ErrorCode, Buffer, Size)
# ErrorCode : DWORD -> "dword"
# Buffer : LPWSTR optional, out -> "char*"
# Size : 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)。