RtmGetRouteInfo

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

DWORD RtmGetRouteInfo(
    INT_PTR RtmRegHandle,
    INT_PTR RouteHandle,
    RTM_ROUTE_INFO* RouteInfo,
    RTM_NET_ADDRESS* DestAddress
);

<DllImport("rtm.dll", ExactSpelling:=True)>
Public Shared Function RtmGetRouteInfo(
    RtmRegHandle As IntPtr,   ' INT_PTR
    RouteHandle As IntPtr,   ' INT_PTR
    RouteInfo As IntPtr,   ' RTM_ROUTE_INFO* in/out
    DestAddress As IntPtr   ' RTM_NET_ADDRESS* in/out
) As UInteger
End Function

' RtmRegHandle : INT_PTR
' RouteHandle : INT_PTR
' RouteInfo : RTM_ROUTE_INFO* in/out
' DestAddress : RTM_NET_ADDRESS* in/out
Declare PtrSafe Function RtmGetRouteInfo Lib "rtm" ( _
    ByVal RtmRegHandle As LongPtr, _
    ByVal RouteHandle As LongPtr, _
    ByVal RouteInfo As LongPtr, _
    ByVal DestAddress 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

RtmGetRouteInfo = ctypes.windll.rtm.RtmGetRouteInfo
RtmGetRouteInfo.restype = wintypes.DWORD
RtmGetRouteInfo.argtypes = [
    ctypes.c_ssize_t,  # RtmRegHandle : INT_PTR
    ctypes.c_ssize_t,  # RouteHandle : INT_PTR
    ctypes.c_void_p,  # RouteInfo : RTM_ROUTE_INFO* in/out
    ctypes.c_void_p,  # DestAddress : RTM_NET_ADDRESS* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('rtm.dll')
RtmGetRouteInfo = Fiddle::Function.new(
  lib['RtmGetRouteInfo'],
  [
    Fiddle::TYPE_INTPTR_T,  # RtmRegHandle : INT_PTR
    Fiddle::TYPE_INTPTR_T,  # RouteHandle : INT_PTR
    Fiddle::TYPE_VOIDP,  # RouteInfo : RTM_ROUTE_INFO* in/out
    Fiddle::TYPE_VOIDP,  # DestAddress : RTM_NET_ADDRESS* in/out
  ],
  -Fiddle::TYPE_INT)

#[link(name = "rtm")]
extern "system" {
    fn RtmGetRouteInfo(
        RtmRegHandle: isize,  // INT_PTR
        RouteHandle: isize,  // INT_PTR
        RouteInfo: *mut RTM_ROUTE_INFO,  // RTM_ROUTE_INFO* in/out
        DestAddress: *mut RTM_NET_ADDRESS  // RTM_NET_ADDRESS* in/out
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("rtm.dll")]
public static extern uint RtmGetRouteInfo(IntPtr RtmRegHandle, IntPtr RouteHandle, IntPtr RouteInfo, IntPtr DestAddress);
"@
$api = Add-Type -MemberDefinition $sig -Name 'rtm_RtmGetRouteInfo' -Namespace Win32 -PassThru
# $api::RtmGetRouteInfo(RtmRegHandle, RouteHandle, RouteInfo, DestAddress)

#uselib "rtm.dll"
#func global RtmGetRouteInfo "RtmGetRouteInfo" sptr, sptr, sptr, sptr
; RtmGetRouteInfo RtmRegHandle, RouteHandle, varptr(RouteInfo), varptr(DestAddress)   ; 戻り値は stat
; RtmRegHandle : INT_PTR -> "sptr"
; RouteHandle : INT_PTR -> "sptr"
; RouteInfo : RTM_ROUTE_INFO* in/out -> "sptr"
; DestAddress : RTM_NET_ADDRESS* 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 "rtm.dll"
#cfunc global RtmGetRouteInfo "RtmGetRouteInfo" sptr, sptr, var, var
; res = RtmGetRouteInfo(RtmRegHandle, RouteHandle, RouteInfo, DestAddress)
; RtmRegHandle : INT_PTR -> "sptr"
; RouteHandle : INT_PTR -> "sptr"
; RouteInfo : RTM_ROUTE_INFO* in/out -> "var"
; DestAddress : RTM_NET_ADDRESS* 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 RtmGetRouteInfo(INT_PTR RtmRegHandle, INT_PTR RouteHandle, RTM_ROUTE_INFO* RouteInfo, RTM_NET_ADDRESS* DestAddress)
#uselib "rtm.dll"
#cfunc global RtmGetRouteInfo "RtmGetRouteInfo" intptr, intptr, var, var
; res = RtmGetRouteInfo(RtmRegHandle, RouteHandle, RouteInfo, DestAddress)
; RtmRegHandle : INT_PTR -> "intptr"
; RouteHandle : INT_PTR -> "intptr"
; RouteInfo : RTM_ROUTE_INFO* in/out -> "var"
; DestAddress : RTM_NET_ADDRESS* 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 (
	rtm = windows.NewLazySystemDLL("rtm.dll")
	procRtmGetRouteInfo = rtm.NewProc("RtmGetRouteInfo")
)

// RtmRegHandle (INT_PTR), RouteHandle (INT_PTR), RouteInfo (RTM_ROUTE_INFO* in/out), DestAddress (RTM_NET_ADDRESS* in/out)
r1, _, err := procRtmGetRouteInfo.Call(
	uintptr(RtmRegHandle),
	uintptr(RouteHandle),
	uintptr(RouteInfo),
	uintptr(DestAddress),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function RtmGetRouteInfo(
  RtmRegHandle: NativeInt;   // INT_PTR
  RouteHandle: NativeInt;   // INT_PTR
  RouteInfo: Pointer;   // RTM_ROUTE_INFO* in/out
  DestAddress: Pointer   // RTM_NET_ADDRESS* in/out
): DWORD; stdcall;
  external 'rtm.dll' name 'RtmGetRouteInfo';

result := DllCall("rtm\RtmGetRouteInfo"
    , "Ptr", RtmRegHandle   ; INT_PTR
    , "Ptr", RouteHandle   ; INT_PTR
    , "Ptr", RouteInfo   ; RTM_ROUTE_INFO* in/out
    , "Ptr", DestAddress   ; RTM_NET_ADDRESS* in/out
    , "UInt")   ; return: DWORD

●RtmGetRouteInfo(RtmRegHandle, RouteHandle, RouteInfo, DestAddress) = DLL("rtm.dll", "dword RtmGetRouteInfo(int, int, void*, void*)")
# 呼び出し: RtmGetRouteInfo(RtmRegHandle, RouteHandle, RouteInfo, DestAddress)
# RtmRegHandle : INT_PTR -> "int"
# RouteHandle : INT_PTR -> "int"
# RouteInfo : RTM_ROUTE_INFO* in/out -> "void*"
# DestAddress : RTM_NET_ADDRESS* 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)。