InternetOpenW

// WININET.dll  (Unicode / -W)
#include <windows.h>

void* InternetOpenW(
    LPCWSTR lpszAgent,   // optional
    DWORD dwAccessType,
    LPCWSTR lpszProxy,   // optional
    LPCWSTR lpszProxyBypass,   // optional
    DWORD dwFlags
);

<DllImport("WININET.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function InternetOpenW(
    <MarshalAs(UnmanagedType.LPWStr)> lpszAgent As String,   ' LPCWSTR optional
    dwAccessType As UInteger,   ' DWORD
    <MarshalAs(UnmanagedType.LPWStr)> lpszProxy As String,   ' LPCWSTR optional
    <MarshalAs(UnmanagedType.LPWStr)> lpszProxyBypass As String,   ' LPCWSTR optional
    dwFlags As UInteger   ' DWORD
) As IntPtr
End Function

' lpszAgent : LPCWSTR optional
' dwAccessType : DWORD
' lpszProxy : LPCWSTR optional
' lpszProxyBypass : LPCWSTR optional
' dwFlags : DWORD
Declare PtrSafe Function InternetOpenW Lib "wininet" ( _
    ByVal lpszAgent As LongPtr, _
    ByVal dwAccessType As Long, _
    ByVal lpszProxy As LongPtr, _
    ByVal lpszProxyBypass As LongPtr, _
    ByVal dwFlags As Long) As LongPtr
' Unicode(W): 文字列は ByVal As LongPtr とし StrPtr(unicodeStr) を渡す
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

InternetOpenW = ctypes.windll.wininet.InternetOpenW
InternetOpenW.restype = ctypes.c_void_p
InternetOpenW.argtypes = [
    wintypes.LPCWSTR,  # lpszAgent : LPCWSTR optional
    wintypes.DWORD,  # dwAccessType : DWORD
    wintypes.LPCWSTR,  # lpszProxy : LPCWSTR optional
    wintypes.LPCWSTR,  # lpszProxyBypass : LPCWSTR optional
    wintypes.DWORD,  # dwFlags : DWORD
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('WININET.dll')
InternetOpenW = Fiddle::Function.new(
  lib['InternetOpenW'],
  [
    Fiddle::TYPE_VOIDP,  # lpszAgent : LPCWSTR optional
    -Fiddle::TYPE_INT,  # dwAccessType : DWORD
    Fiddle::TYPE_VOIDP,  # lpszProxy : LPCWSTR optional
    Fiddle::TYPE_VOIDP,  # lpszProxyBypass : LPCWSTR optional
    -Fiddle::TYPE_INT,  # dwFlags : DWORD
  ],
  Fiddle::TYPE_VOIDP)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "wininet")]
extern "system" {
    fn InternetOpenW(
        lpszAgent: *const u16,  // LPCWSTR optional
        dwAccessType: u32,  // DWORD
        lpszProxy: *const u16,  // LPCWSTR optional
        lpszProxyBypass: *const u16,  // LPCWSTR optional
        dwFlags: u32  // DWORD
    ) -> *mut ();
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("WININET.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern IntPtr InternetOpenW([MarshalAs(UnmanagedType.LPWStr)] string lpszAgent, uint dwAccessType, [MarshalAs(UnmanagedType.LPWStr)] string lpszProxy, [MarshalAs(UnmanagedType.LPWStr)] string lpszProxyBypass, uint dwFlags);
"@
$api = Add-Type -MemberDefinition $sig -Name 'WININET_InternetOpenW' -Namespace Win32 -PassThru
# $api::InternetOpenW(lpszAgent, dwAccessType, lpszProxy, lpszProxyBypass, dwFlags)

#uselib "WININET.dll"
#func global InternetOpenW "InternetOpenW" wptr, wptr, wptr, wptr, wptr
; InternetOpenW lpszAgent, dwAccessType, lpszProxy, lpszProxyBypass, dwFlags   ; 戻り値は stat
; lpszAgent : LPCWSTR optional -> "wptr"
; dwAccessType : DWORD -> "wptr"
; lpszProxy : LPCWSTR optional -> "wptr"
; lpszProxyBypass : LPCWSTR optional -> "wptr"
; dwFlags : DWORD -> "wptr"
; ※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 "WININET.dll"
#cfunc global InternetOpenW "InternetOpenW" wstr, int, wstr, wstr, int
; res = InternetOpenW(lpszAgent, dwAccessType, lpszProxy, lpszProxyBypass, dwFlags)
; lpszAgent : LPCWSTR optional -> "wstr"
; dwAccessType : DWORD -> "int"
; lpszProxy : LPCWSTR optional -> "wstr"
; lpszProxyBypass : LPCWSTR optional -> "wstr"
; dwFlags : DWORD -> "int"

; void* InternetOpenW(LPCWSTR lpszAgent, DWORD dwAccessType, LPCWSTR lpszProxy, LPCWSTR lpszProxyBypass, DWORD dwFlags)
#uselib "WININET.dll"
#cfunc global InternetOpenW "InternetOpenW" wstr, int, wstr, wstr, int
; res = InternetOpenW(lpszAgent, dwAccessType, lpszProxy, lpszProxyBypass, dwFlags)
; lpszAgent : LPCWSTR optional -> "wstr"
; dwAccessType : DWORD -> "int"
; lpszProxy : LPCWSTR optional -> "wstr"
; lpszProxyBypass : LPCWSTR optional -> "wstr"
; dwFlags : DWORD -> "int"

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	wininet = windows.NewLazySystemDLL("WININET.dll")
	procInternetOpenW = wininet.NewProc("InternetOpenW")
)

// lpszAgent (LPCWSTR optional), dwAccessType (DWORD), lpszProxy (LPCWSTR optional), lpszProxyBypass (LPCWSTR optional), dwFlags (DWORD)
r1, _, err := procInternetOpenW.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszAgent))),
	uintptr(dwAccessType),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszProxy))),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszProxyBypass))),
	uintptr(dwFlags),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // void*

function InternetOpenW(
  lpszAgent: PWideChar;   // LPCWSTR optional
  dwAccessType: DWORD;   // DWORD
  lpszProxy: PWideChar;   // LPCWSTR optional
  lpszProxyBypass: PWideChar;   // LPCWSTR optional
  dwFlags: DWORD   // DWORD
): Pointer; stdcall;
  external 'WININET.dll' name 'InternetOpenW';

result := DllCall("WININET\InternetOpenW"
    , "WStr", lpszAgent   ; LPCWSTR optional
    , "UInt", dwAccessType   ; DWORD
    , "WStr", lpszProxy   ; LPCWSTR optional
    , "WStr", lpszProxyBypass   ; LPCWSTR optional
    , "UInt", dwFlags   ; DWORD
    , "Ptr")   ; return: void*

●InternetOpenW(lpszAgent, dwAccessType, lpszProxy, lpszProxyBypass, dwFlags) = DLL("WININET.dll", "void* InternetOpenW(char*, dword, char*, char*, dword)")
# 呼び出し: InternetOpenW(lpszAgent, dwAccessType, lpszProxy, lpszProxyBypass, dwFlags)
# lpszAgent : LPCWSTR optional -> "char*"
# dwAccessType : DWORD -> "dword"
# lpszProxy : LPCWSTR optional -> "char*"
# lpszProxyBypass : LPCWSTR optional -> "char*"
# dwFlags : DWORD -> "dword"
# 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)。
# ※-W(Unicode)関数。なでしこ1はANSIのため -A 版の利用を推奨。