getpeername

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

INT getpeername(
    SOCKET s,
    SOCKADDR* name,
    INT* namelen
);

<DllImport("WS2_32.dll", SetLastError:=True, ExactSpelling:=True)>
Public Shared Function getpeername(
    s As UIntPtr,   ' SOCKET
    name As IntPtr,   ' SOCKADDR* out
    ByRef namelen As Integer   ' INT* in/out
) As Integer
End Function

' s : SOCKET
' name : SOCKADDR* out
' namelen : INT* in/out
Declare PtrSafe Function getpeername Lib "ws2_32" ( _
    ByVal s As LongPtr, _
    ByVal name As LongPtr, _
    ByRef namelen 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

getpeername = ctypes.windll.ws2_32.getpeername
getpeername.restype = ctypes.c_int
getpeername.argtypes = [
    ctypes.c_size_t,  # s : SOCKET
    ctypes.c_void_p,  # name : SOCKADDR* out
    ctypes.POINTER(ctypes.c_int),  # namelen : INT* in/out
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('WS2_32.dll')
getpeername = Fiddle::Function.new(
  lib['getpeername'],
  [
    Fiddle::TYPE_UINTPTR_T,  # s : SOCKET
    Fiddle::TYPE_VOIDP,  # name : SOCKADDR* out
    Fiddle::TYPE_VOIDP,  # namelen : INT* in/out
  ],
  Fiddle::TYPE_INT)

#[link(name = "ws2_32")]
extern "system" {
    fn getpeername(
        s: usize,  // SOCKET
        name: *mut SOCKADDR,  // SOCKADDR* out
        namelen: *mut i32  // INT* in/out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("WS2_32.dll", SetLastError = true)]
public static extern int getpeername(UIntPtr s, IntPtr name, ref int namelen);
"@
$api = Add-Type -MemberDefinition $sig -Name 'WS2_32_getpeername' -Namespace Win32 -PassThru
# $api::getpeername(s, name, namelen)

#uselib "WS2_32.dll"
#func global getpeername "getpeername" sptr, sptr, sptr
; getpeername s, varptr(name), varptr(namelen)   ; 戻り値は stat
; s : SOCKET -> "sptr"
; name : SOCKADDR* out -> "sptr"
; namelen : INT* 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 "WS2_32.dll"
#cfunc global getpeername "getpeername" sptr, var, var
; res = getpeername(s, name, namelen)
; s : SOCKET -> "sptr"
; name : SOCKADDR* out -> "var"
; namelen : INT* 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。

; INT getpeername(SOCKET s, SOCKADDR* name, INT* namelen)
#uselib "WS2_32.dll"
#cfunc global getpeername "getpeername" intptr, var, var
; res = getpeername(s, name, namelen)
; s : SOCKET -> "intptr"
; name : SOCKADDR* out -> "var"
; namelen : INT* 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 (
	ws2_32 = windows.NewLazySystemDLL("WS2_32.dll")
	procgetpeername = ws2_32.NewProc("getpeername")
)

// s (SOCKET), name (SOCKADDR* out), namelen (INT* in/out)
r1, _, err := procgetpeername.Call(
	uintptr(s),
	uintptr(name),
	uintptr(namelen),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function getpeername(
  s: NativeUInt;   // SOCKET
  name: Pointer;   // SOCKADDR* out
  namelen: Pointer   // INT* in/out
): Integer; stdcall;
  external 'WS2_32.dll' name 'getpeername';

result := DllCall("WS2_32\getpeername"
    , "UPtr", s   ; SOCKET
    , "Ptr", name   ; SOCKADDR* out
    , "Ptr", namelen   ; INT* in/out
    , "Int")   ; return: INT

●getpeername(s, name, namelen) = DLL("WS2_32.dll", "int getpeername(int, void*, void*)")
# 呼び出し: getpeername(s, name, namelen)
# s : SOCKET -> "int"
# name : SOCKADDR* out -> "void*"
# namelen : INT* 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)。