setsockopt

// WS2_32.dll
#include <windows.h>

INT setsockopt(
    SOCKET s,
    INT level,
    INT optname,
    LPCSTR optval,   // optional
    INT optlen
);

<DllImport("WS2_32.dll", SetLastError:=True, ExactSpelling:=True)>
Public Shared Function setsockopt(
    s As UIntPtr,   ' SOCKET
    level As Integer,   ' INT
    optname As Integer,   ' INT
    <MarshalAs(UnmanagedType.LPStr)> optval As String,   ' LPCSTR optional
    optlen As Integer   ' INT
) As Integer
End Function

' s : SOCKET
' level : INT
' optname : INT
' optval : LPCSTR optional
' optlen : INT
Declare PtrSafe Function setsockopt Lib "ws2_32" ( _
    ByVal s As LongPtr, _
    ByVal level As Long, _
    ByVal optname As Long, _
    ByVal optval As String, _
    ByVal optlen 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

setsockopt = ctypes.windll.ws2_32.setsockopt
setsockopt.restype = ctypes.c_int
setsockopt.argtypes = [
    ctypes.c_size_t,  # s : SOCKET
    ctypes.c_int,  # level : INT
    ctypes.c_int,  # optname : INT
    wintypes.LPCSTR,  # optval : LPCSTR optional
    ctypes.c_int,  # optlen : INT
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('WS2_32.dll')
setsockopt = Fiddle::Function.new(
  lib['setsockopt'],
  [
    Fiddle::TYPE_UINTPTR_T,  # s : SOCKET
    Fiddle::TYPE_INT,  # level : INT
    Fiddle::TYPE_INT,  # optname : INT
    Fiddle::TYPE_VOIDP,  # optval : LPCSTR optional
    Fiddle::TYPE_INT,  # optlen : INT
  ],
  Fiddle::TYPE_INT)

#[link(name = "ws2_32")]
extern "system" {
    fn setsockopt(
        s: usize,  // SOCKET
        level: i32,  // INT
        optname: i32,  // INT
        optval: *const u8,  // LPCSTR optional
        optlen: i32  // INT
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("WS2_32.dll", SetLastError = true)]
public static extern int setsockopt(UIntPtr s, int level, int optname, [MarshalAs(UnmanagedType.LPStr)] string optval, int optlen);
"@
$api = Add-Type -MemberDefinition $sig -Name 'WS2_32_setsockopt' -Namespace Win32 -PassThru
# $api::setsockopt(s, level, optname, optval, optlen)

#uselib "WS2_32.dll"
#func global setsockopt "setsockopt" sptr, sptr, sptr, sptr, sptr
; setsockopt s, level, optname, optval, optlen   ; 戻り値は stat
; s : SOCKET -> "sptr"
; level : INT -> "sptr"
; optname : INT -> "sptr"
; optval : LPCSTR optional -> "sptr"
; optlen : INT -> "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 "WS2_32.dll"
#cfunc global setsockopt "setsockopt" sptr, int, int, str, int
; res = setsockopt(s, level, optname, optval, optlen)
; s : SOCKET -> "sptr"
; level : INT -> "int"
; optname : INT -> "int"
; optval : LPCSTR optional -> "str"
; optlen : INT -> "int"

; INT setsockopt(SOCKET s, INT level, INT optname, LPCSTR optval, INT optlen)
#uselib "WS2_32.dll"
#cfunc global setsockopt "setsockopt" intptr, int, int, str, int
; res = setsockopt(s, level, optname, optval, optlen)
; s : SOCKET -> "intptr"
; level : INT -> "int"
; optname : INT -> "int"
; optval : LPCSTR optional -> "str"
; optlen : INT -> "int"

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

var (
	ws2_32 = windows.NewLazySystemDLL("WS2_32.dll")
	procsetsockopt = ws2_32.NewProc("setsockopt")
)

// s (SOCKET), level (INT), optname (INT), optval (LPCSTR optional), optlen (INT)
r1, _, err := procsetsockopt.Call(
	uintptr(s),
	uintptr(level),
	uintptr(optname),
	uintptr(unsafe.Pointer(windows.BytePtrFromString(optval))),
	uintptr(optlen),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function setsockopt(
  s: NativeUInt;   // SOCKET
  level: Integer;   // INT
  optname: Integer;   // INT
  optval: PAnsiChar;   // LPCSTR optional
  optlen: Integer   // INT
): Integer; stdcall;
  external 'WS2_32.dll' name 'setsockopt';

result := DllCall("WS2_32\setsockopt"
    , "UPtr", s   ; SOCKET
    , "Int", level   ; INT
    , "Int", optname   ; INT
    , "AStr", optval   ; LPCSTR optional
    , "Int", optlen   ; INT
    , "Int")   ; return: INT

●setsockopt(s, level, optname, optval, optlen) = DLL("WS2_32.dll", "int setsockopt(int, int, int, char*, int)")
# 呼び出し: setsockopt(s, level, optname, optval, optlen)
# s : SOCKET -> "int"
# level : INT -> "int"
# optname : INT -> "int"
# optval : LPCSTR optional -> "char*"
# optlen : INT -> "int"
# 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)。