DnsGetProxyInformation

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

DWORD DnsGetProxyInformation(
    LPCWSTR hostName,
    DNS_PROXY_INFORMATION* proxyInformation,
    DNS_PROXY_INFORMATION* defaultProxyInformation,   // optional
    DNS_PROXY_COMPLETION_ROUTINE completionRoutine,   // optional
    void* completionContext   // optional
);

<DllImport("DNSAPI.dll", ExactSpelling:=True)>
Public Shared Function DnsGetProxyInformation(
    <MarshalAs(UnmanagedType.LPWStr)> hostName As String,   ' LPCWSTR
    proxyInformation As IntPtr,   ' DNS_PROXY_INFORMATION* in/out
    defaultProxyInformation As IntPtr,   ' DNS_PROXY_INFORMATION* optional, in/out
    completionRoutine As IntPtr,   ' DNS_PROXY_COMPLETION_ROUTINE optional
    completionContext As IntPtr   ' void* optional
) As UInteger
End Function

' hostName : LPCWSTR
' proxyInformation : DNS_PROXY_INFORMATION* in/out
' defaultProxyInformation : DNS_PROXY_INFORMATION* optional, in/out
' completionRoutine : DNS_PROXY_COMPLETION_ROUTINE optional
' completionContext : void* optional
Declare PtrSafe Function DnsGetProxyInformation Lib "dnsapi" ( _
    ByVal hostName As LongPtr, _
    ByVal proxyInformation As LongPtr, _
    ByVal defaultProxyInformation As LongPtr, _
    ByVal completionRoutine As LongPtr, _
    ByVal completionContext 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

DnsGetProxyInformation = ctypes.windll.dnsapi.DnsGetProxyInformation
DnsGetProxyInformation.restype = wintypes.DWORD
DnsGetProxyInformation.argtypes = [
    wintypes.LPCWSTR,  # hostName : LPCWSTR
    ctypes.c_void_p,  # proxyInformation : DNS_PROXY_INFORMATION* in/out
    ctypes.c_void_p,  # defaultProxyInformation : DNS_PROXY_INFORMATION* optional, in/out
    ctypes.c_void_p,  # completionRoutine : DNS_PROXY_COMPLETION_ROUTINE optional
    ctypes.POINTER(None),  # completionContext : void* optional
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('DNSAPI.dll')
DnsGetProxyInformation = Fiddle::Function.new(
  lib['DnsGetProxyInformation'],
  [
    Fiddle::TYPE_VOIDP,  # hostName : LPCWSTR
    Fiddle::TYPE_VOIDP,  # proxyInformation : DNS_PROXY_INFORMATION* in/out
    Fiddle::TYPE_VOIDP,  # defaultProxyInformation : DNS_PROXY_INFORMATION* optional, in/out
    Fiddle::TYPE_VOIDP,  # completionRoutine : DNS_PROXY_COMPLETION_ROUTINE optional
    Fiddle::TYPE_VOIDP,  # completionContext : void* optional
  ],
  -Fiddle::TYPE_INT)

#[link(name = "dnsapi")]
extern "system" {
    fn DnsGetProxyInformation(
        hostName: *const u16,  // LPCWSTR
        proxyInformation: *mut DNS_PROXY_INFORMATION,  // DNS_PROXY_INFORMATION* in/out
        defaultProxyInformation: *mut DNS_PROXY_INFORMATION,  // DNS_PROXY_INFORMATION* optional, in/out
        completionRoutine: *const core::ffi::c_void,  // DNS_PROXY_COMPLETION_ROUTINE optional
        completionContext: *mut ()  // void* optional
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("DNSAPI.dll")]
public static extern uint DnsGetProxyInformation([MarshalAs(UnmanagedType.LPWStr)] string hostName, IntPtr proxyInformation, IntPtr defaultProxyInformation, IntPtr completionRoutine, IntPtr completionContext);
"@
$api = Add-Type -MemberDefinition $sig -Name 'DNSAPI_DnsGetProxyInformation' -Namespace Win32 -PassThru
# $api::DnsGetProxyInformation(hostName, proxyInformation, defaultProxyInformation, completionRoutine, completionContext)

#uselib "DNSAPI.dll"
#func global DnsGetProxyInformation "DnsGetProxyInformation" sptr, sptr, sptr, sptr, sptr
; DnsGetProxyInformation hostName, varptr(proxyInformation), varptr(defaultProxyInformation), completionRoutine, completionContext   ; 戻り値は stat
; hostName : LPCWSTR -> "sptr"
; proxyInformation : DNS_PROXY_INFORMATION* in/out -> "sptr"
; defaultProxyInformation : DNS_PROXY_INFORMATION* optional, in/out -> "sptr"
; completionRoutine : DNS_PROXY_COMPLETION_ROUTINE optional -> "sptr"
; completionContext : void* optional -> "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 "DNSAPI.dll"
#cfunc global DnsGetProxyInformation "DnsGetProxyInformation" wstr, var, var, sptr, sptr
; res = DnsGetProxyInformation(hostName, proxyInformation, defaultProxyInformation, completionRoutine, completionContext)
; hostName : LPCWSTR -> "wstr"
; proxyInformation : DNS_PROXY_INFORMATION* in/out -> "var"
; defaultProxyInformation : DNS_PROXY_INFORMATION* optional, in/out -> "var"
; completionRoutine : DNS_PROXY_COMPLETION_ROUTINE optional -> "sptr"
; completionContext : void* optional -> "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。

; DWORD DnsGetProxyInformation(LPCWSTR hostName, DNS_PROXY_INFORMATION* proxyInformation, DNS_PROXY_INFORMATION* defaultProxyInformation, DNS_PROXY_COMPLETION_ROUTINE completionRoutine, void* completionContext)
#uselib "DNSAPI.dll"
#cfunc global DnsGetProxyInformation "DnsGetProxyInformation" wstr, var, var, intptr, intptr
; res = DnsGetProxyInformation(hostName, proxyInformation, defaultProxyInformation, completionRoutine, completionContext)
; hostName : LPCWSTR -> "wstr"
; proxyInformation : DNS_PROXY_INFORMATION* in/out -> "var"
; defaultProxyInformation : DNS_PROXY_INFORMATION* optional, in/out -> "var"
; completionRoutine : DNS_PROXY_COMPLETION_ROUTINE optional -> "intptr"
; completionContext : void* optional -> "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 (
	dnsapi = windows.NewLazySystemDLL("DNSAPI.dll")
	procDnsGetProxyInformation = dnsapi.NewProc("DnsGetProxyInformation")
)

// hostName (LPCWSTR), proxyInformation (DNS_PROXY_INFORMATION* in/out), defaultProxyInformation (DNS_PROXY_INFORMATION* optional, in/out), completionRoutine (DNS_PROXY_COMPLETION_ROUTINE optional), completionContext (void* optional)
r1, _, err := procDnsGetProxyInformation.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(hostName))),
	uintptr(proxyInformation),
	uintptr(defaultProxyInformation),
	uintptr(completionRoutine),
	uintptr(completionContext),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function DnsGetProxyInformation(
  hostName: PWideChar;   // LPCWSTR
  proxyInformation: Pointer;   // DNS_PROXY_INFORMATION* in/out
  defaultProxyInformation: Pointer;   // DNS_PROXY_INFORMATION* optional, in/out
  completionRoutine: Pointer;   // DNS_PROXY_COMPLETION_ROUTINE optional
  completionContext: Pointer   // void* optional
): DWORD; stdcall;
  external 'DNSAPI.dll' name 'DnsGetProxyInformation';

result := DllCall("DNSAPI\DnsGetProxyInformation"
    , "WStr", hostName   ; LPCWSTR
    , "Ptr", proxyInformation   ; DNS_PROXY_INFORMATION* in/out
    , "Ptr", defaultProxyInformation   ; DNS_PROXY_INFORMATION* optional, in/out
    , "Ptr", completionRoutine   ; DNS_PROXY_COMPLETION_ROUTINE optional
    , "Ptr", completionContext   ; void* optional
    , "UInt")   ; return: DWORD

●DnsGetProxyInformation(hostName, proxyInformation, defaultProxyInformation, completionRoutine, completionContext) = DLL("DNSAPI.dll", "dword DnsGetProxyInformation(char*, void*, void*, void*, void*)")
# 呼び出し: DnsGetProxyInformation(hostName, proxyInformation, defaultProxyInformation, completionRoutine, completionContext)
# hostName : LPCWSTR -> "char*"
# proxyInformation : DNS_PROXY_INFORMATION* in/out -> "void*"
# defaultProxyInformation : DNS_PROXY_INFORMATION* optional, in/out -> "void*"
# completionRoutine : DNS_PROXY_COMPLETION_ROUTINE optional -> "void*"
# completionContext : void* optional -> "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)。