DnsConnectionSetProxyInfo

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

DWORD DnsConnectionSetProxyInfo(
    LPCWSTR pwszConnectionName,
    DNS_CONNECTION_PROXY_TYPE Type,
    const DNS_CONNECTION_PROXY_INFO* pProxyInfo
);

<DllImport("DNSAPI.dll", ExactSpelling:=True)>
Public Shared Function DnsConnectionSetProxyInfo(
    <MarshalAs(UnmanagedType.LPWStr)> pwszConnectionName As String,   ' LPCWSTR
    Type As Integer,   ' DNS_CONNECTION_PROXY_TYPE
    pProxyInfo As IntPtr   ' DNS_CONNECTION_PROXY_INFO*
) As UInteger
End Function

' pwszConnectionName : LPCWSTR
' Type : DNS_CONNECTION_PROXY_TYPE
' pProxyInfo : DNS_CONNECTION_PROXY_INFO*
Declare PtrSafe Function DnsConnectionSetProxyInfo Lib "dnsapi" ( _
    ByVal pwszConnectionName As LongPtr, _
    ByVal Type As Long, _
    ByVal pProxyInfo 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

DnsConnectionSetProxyInfo = ctypes.windll.dnsapi.DnsConnectionSetProxyInfo
DnsConnectionSetProxyInfo.restype = wintypes.DWORD
DnsConnectionSetProxyInfo.argtypes = [
    wintypes.LPCWSTR,  # pwszConnectionName : LPCWSTR
    ctypes.c_int,  # Type : DNS_CONNECTION_PROXY_TYPE
    ctypes.c_void_p,  # pProxyInfo : DNS_CONNECTION_PROXY_INFO*
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('DNSAPI.dll')
DnsConnectionSetProxyInfo = Fiddle::Function.new(
  lib['DnsConnectionSetProxyInfo'],
  [
    Fiddle::TYPE_VOIDP,  # pwszConnectionName : LPCWSTR
    Fiddle::TYPE_INT,  # Type : DNS_CONNECTION_PROXY_TYPE
    Fiddle::TYPE_VOIDP,  # pProxyInfo : DNS_CONNECTION_PROXY_INFO*
  ],
  -Fiddle::TYPE_INT)

#[link(name = "dnsapi")]
extern "system" {
    fn DnsConnectionSetProxyInfo(
        pwszConnectionName: *const u16,  // LPCWSTR
        Type: i32,  // DNS_CONNECTION_PROXY_TYPE
        pProxyInfo: *const DNS_CONNECTION_PROXY_INFO  // DNS_CONNECTION_PROXY_INFO*
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("DNSAPI.dll")]
public static extern uint DnsConnectionSetProxyInfo([MarshalAs(UnmanagedType.LPWStr)] string pwszConnectionName, int Type, IntPtr pProxyInfo);
"@
$api = Add-Type -MemberDefinition $sig -Name 'DNSAPI_DnsConnectionSetProxyInfo' -Namespace Win32 -PassThru
# $api::DnsConnectionSetProxyInfo(pwszConnectionName, Type, pProxyInfo)

#uselib "DNSAPI.dll"
#func global DnsConnectionSetProxyInfo "DnsConnectionSetProxyInfo" sptr, sptr, sptr
; DnsConnectionSetProxyInfo pwszConnectionName, Type, varptr(pProxyInfo)   ; 戻り値は stat
; pwszConnectionName : LPCWSTR -> "sptr"
; Type : DNS_CONNECTION_PROXY_TYPE -> "sptr"
; pProxyInfo : DNS_CONNECTION_PROXY_INFO* -> "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 DnsConnectionSetProxyInfo "DnsConnectionSetProxyInfo" wstr, int, var
; res = DnsConnectionSetProxyInfo(pwszConnectionName, Type, pProxyInfo)
; pwszConnectionName : LPCWSTR -> "wstr"
; Type : DNS_CONNECTION_PROXY_TYPE -> "int"
; pProxyInfo : DNS_CONNECTION_PROXY_INFO* -> "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 DnsConnectionSetProxyInfo(LPCWSTR pwszConnectionName, DNS_CONNECTION_PROXY_TYPE Type, DNS_CONNECTION_PROXY_INFO* pProxyInfo)
#uselib "DNSAPI.dll"
#cfunc global DnsConnectionSetProxyInfo "DnsConnectionSetProxyInfo" wstr, int, var
; res = DnsConnectionSetProxyInfo(pwszConnectionName, Type, pProxyInfo)
; pwszConnectionName : LPCWSTR -> "wstr"
; Type : DNS_CONNECTION_PROXY_TYPE -> "int"
; pProxyInfo : DNS_CONNECTION_PROXY_INFO* -> "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 (
	dnsapi = windows.NewLazySystemDLL("DNSAPI.dll")
	procDnsConnectionSetProxyInfo = dnsapi.NewProc("DnsConnectionSetProxyInfo")
)

// pwszConnectionName (LPCWSTR), Type (DNS_CONNECTION_PROXY_TYPE), pProxyInfo (DNS_CONNECTION_PROXY_INFO*)
r1, _, err := procDnsConnectionSetProxyInfo.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(pwszConnectionName))),
	uintptr(Type),
	uintptr(pProxyInfo),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function DnsConnectionSetProxyInfo(
  pwszConnectionName: PWideChar;   // LPCWSTR
  Type: Integer;   // DNS_CONNECTION_PROXY_TYPE
  pProxyInfo: Pointer   // DNS_CONNECTION_PROXY_INFO*
): DWORD; stdcall;
  external 'DNSAPI.dll' name 'DnsConnectionSetProxyInfo';

result := DllCall("DNSAPI\DnsConnectionSetProxyInfo"
    , "WStr", pwszConnectionName   ; LPCWSTR
    , "Int", Type   ; DNS_CONNECTION_PROXY_TYPE
    , "Ptr", pProxyInfo   ; DNS_CONNECTION_PROXY_INFO*
    , "UInt")   ; return: DWORD

●DnsConnectionSetProxyInfo(pwszConnectionName, Type, pProxyInfo) = DLL("DNSAPI.dll", "dword DnsConnectionSetProxyInfo(char*, int, void*)")
# 呼び出し: DnsConnectionSetProxyInfo(pwszConnectionName, Type, pProxyInfo)
# pwszConnectionName : LPCWSTR -> "char*"
# Type : DNS_CONNECTION_PROXY_TYPE -> "int"
# pProxyInfo : DNS_CONNECTION_PROXY_INFO* -> "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)。