WTSEnumerateSessionsW

// WTSAPI32.dll  (Unicode / -W)
#include <windows.h>

BOOL WTSEnumerateSessionsW(
    HANDLE hServer,   // optional
    DWORD Reserved,
    DWORD Version,
    WTS_SESSION_INFOW** ppSessionInfo,
    DWORD* pCount
);

<DllImport("WTSAPI32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function WTSEnumerateSessionsW(
    hServer As IntPtr,   ' HANDLE optional
    Reserved As UInteger,   ' DWORD
    Version As UInteger,   ' DWORD
    ppSessionInfo As IntPtr,   ' WTS_SESSION_INFOW** out
    <Out> ByRef pCount As UInteger   ' DWORD* out
) As Boolean
End Function

' hServer : HANDLE optional
' Reserved : DWORD
' Version : DWORD
' ppSessionInfo : WTS_SESSION_INFOW** out
' pCount : DWORD* out
Declare PtrSafe Function WTSEnumerateSessionsW Lib "wtsapi32" ( _
    ByVal hServer As LongPtr, _
    ByVal Reserved As Long, _
    ByVal Version As Long, _
    ByVal ppSessionInfo As LongPtr, _
    ByRef pCount As Long) As Long
' 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

WTSEnumerateSessionsW = ctypes.windll.wtsapi32.WTSEnumerateSessionsW
WTSEnumerateSessionsW.restype = wintypes.BOOL
WTSEnumerateSessionsW.argtypes = [
    wintypes.HANDLE,  # hServer : HANDLE optional
    wintypes.DWORD,  # Reserved : DWORD
    wintypes.DWORD,  # Version : DWORD
    ctypes.c_void_p,  # ppSessionInfo : WTS_SESSION_INFOW** out
    ctypes.POINTER(wintypes.DWORD),  # pCount : DWORD* out
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('WTSAPI32.dll')
WTSEnumerateSessionsW = Fiddle::Function.new(
  lib['WTSEnumerateSessionsW'],
  [
    Fiddle::TYPE_VOIDP,  # hServer : HANDLE optional
    -Fiddle::TYPE_INT,  # Reserved : DWORD
    -Fiddle::TYPE_INT,  # Version : DWORD
    Fiddle::TYPE_VOIDP,  # ppSessionInfo : WTS_SESSION_INFOW** out
    Fiddle::TYPE_VOIDP,  # pCount : DWORD* out
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "wtsapi32")]
extern "system" {
    fn WTSEnumerateSessionsW(
        hServer: *mut core::ffi::c_void,  // HANDLE optional
        Reserved: u32,  // DWORD
        Version: u32,  // DWORD
        ppSessionInfo: *mut *mut WTS_SESSION_INFOW,  // WTS_SESSION_INFOW** out
        pCount: *mut u32  // DWORD* out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("WTSAPI32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern bool WTSEnumerateSessionsW(IntPtr hServer, uint Reserved, uint Version, IntPtr ppSessionInfo, out uint pCount);
"@
$api = Add-Type -MemberDefinition $sig -Name 'WTSAPI32_WTSEnumerateSessionsW' -Namespace Win32 -PassThru
# $api::WTSEnumerateSessionsW(hServer, Reserved, Version, ppSessionInfo, pCount)

#uselib "WTSAPI32.dll"
#func global WTSEnumerateSessionsW "WTSEnumerateSessionsW" wptr, wptr, wptr, wptr, wptr
; WTSEnumerateSessionsW hServer, Reserved, Version, varptr(ppSessionInfo), varptr(pCount)   ; 戻り値は stat
; hServer : HANDLE optional -> "wptr"
; Reserved : DWORD -> "wptr"
; Version : DWORD -> "wptr"
; ppSessionInfo : WTS_SESSION_INFOW** out -> "wptr"
; pCount : DWORD* out -> "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 "WTSAPI32.dll"
#cfunc global WTSEnumerateSessionsW "WTSEnumerateSessionsW" sptr, int, int, var, var
; res = WTSEnumerateSessionsW(hServer, Reserved, Version, ppSessionInfo, pCount)
; hServer : HANDLE optional -> "sptr"
; Reserved : DWORD -> "int"
; Version : DWORD -> "int"
; ppSessionInfo : WTS_SESSION_INFOW** out -> "var"
; pCount : DWORD* 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。

; BOOL WTSEnumerateSessionsW(HANDLE hServer, DWORD Reserved, DWORD Version, WTS_SESSION_INFOW** ppSessionInfo, DWORD* pCount)
#uselib "WTSAPI32.dll"
#cfunc global WTSEnumerateSessionsW "WTSEnumerateSessionsW" intptr, int, int, var, var
; res = WTSEnumerateSessionsW(hServer, Reserved, Version, ppSessionInfo, pCount)
; hServer : HANDLE optional -> "intptr"
; Reserved : DWORD -> "int"
; Version : DWORD -> "int"
; ppSessionInfo : WTS_SESSION_INFOW** out -> "var"
; pCount : DWORD* 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 (
	wtsapi32 = windows.NewLazySystemDLL("WTSAPI32.dll")
	procWTSEnumerateSessionsW = wtsapi32.NewProc("WTSEnumerateSessionsW")
)

// hServer (HANDLE optional), Reserved (DWORD), Version (DWORD), ppSessionInfo (WTS_SESSION_INFOW** out), pCount (DWORD* out)
r1, _, err := procWTSEnumerateSessionsW.Call(
	uintptr(hServer),
	uintptr(Reserved),
	uintptr(Version),
	uintptr(ppSessionInfo),
	uintptr(pCount),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function WTSEnumerateSessionsW(
  hServer: THandle;   // HANDLE optional
  Reserved: DWORD;   // DWORD
  Version: DWORD;   // DWORD
  ppSessionInfo: Pointer;   // WTS_SESSION_INFOW** out
  pCount: Pointer   // DWORD* out
): BOOL; stdcall;
  external 'WTSAPI32.dll' name 'WTSEnumerateSessionsW';

result := DllCall("WTSAPI32\WTSEnumerateSessionsW"
    , "Ptr", hServer   ; HANDLE optional
    , "UInt", Reserved   ; DWORD
    , "UInt", Version   ; DWORD
    , "Ptr", ppSessionInfo   ; WTS_SESSION_INFOW** out
    , "Ptr", pCount   ; DWORD* out
    , "Int")   ; return: BOOL

●WTSEnumerateSessionsW(hServer, Reserved, Version, ppSessionInfo, pCount) = DLL("WTSAPI32.dll", "bool WTSEnumerateSessionsW(void*, dword, dword, void*, void*)")
# 呼び出し: WTSEnumerateSessionsW(hServer, Reserved, Version, ppSessionInfo, pCount)
# hServer : HANDLE optional -> "void*"
# Reserved : DWORD -> "dword"
# Version : DWORD -> "dword"
# ppSessionInfo : WTS_SESSION_INFOW** out -> "void*"
# pCount : DWORD* 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)。
# ※-W(Unicode)関数。なでしこ1はANSIのため -A 版の利用を推奨。