OpenDesktopW

// USER32.dll  (Unicode / -W)
#include <windows.h>

HDESK OpenDesktopW(
    LPCWSTR lpszDesktop,
    DESKTOP_CONTROL_FLAGS dwFlags,
    BOOL fInherit,
    DWORD dwDesiredAccess
);

<DllImport("USER32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function OpenDesktopW(
    <MarshalAs(UnmanagedType.LPWStr)> lpszDesktop As String,   ' LPCWSTR
    dwFlags As UInteger,   ' DESKTOP_CONTROL_FLAGS
    fInherit As Boolean,   ' BOOL
    dwDesiredAccess As UInteger   ' DWORD
) As IntPtr
End Function

' lpszDesktop : LPCWSTR
' dwFlags : DESKTOP_CONTROL_FLAGS
' fInherit : BOOL
' dwDesiredAccess : DWORD
Declare PtrSafe Function OpenDesktopW Lib "user32" ( _
    ByVal lpszDesktop As LongPtr, _
    ByVal dwFlags As Long, _
    ByVal fInherit As Long, _
    ByVal dwDesiredAccess 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

OpenDesktopW = ctypes.windll.user32.OpenDesktopW
OpenDesktopW.restype = ctypes.c_void_p
OpenDesktopW.argtypes = [
    wintypes.LPCWSTR,  # lpszDesktop : LPCWSTR
    wintypes.DWORD,  # dwFlags : DESKTOP_CONTROL_FLAGS
    wintypes.BOOL,  # fInherit : BOOL
    wintypes.DWORD,  # dwDesiredAccess : DWORD
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
OpenDesktopW = Fiddle::Function.new(
  lib['OpenDesktopW'],
  [
    Fiddle::TYPE_VOIDP,  # lpszDesktop : LPCWSTR
    -Fiddle::TYPE_INT,  # dwFlags : DESKTOP_CONTROL_FLAGS
    Fiddle::TYPE_INT,  # fInherit : BOOL
    -Fiddle::TYPE_INT,  # dwDesiredAccess : DWORD
  ],
  Fiddle::TYPE_VOIDP)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "user32")]
extern "system" {
    fn OpenDesktopW(
        lpszDesktop: *const u16,  // LPCWSTR
        dwFlags: u32,  // DESKTOP_CONTROL_FLAGS
        fInherit: i32,  // BOOL
        dwDesiredAccess: u32  // DWORD
    ) -> *mut core::ffi::c_void;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern IntPtr OpenDesktopW([MarshalAs(UnmanagedType.LPWStr)] string lpszDesktop, uint dwFlags, bool fInherit, uint dwDesiredAccess);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_OpenDesktopW' -Namespace Win32 -PassThru
# $api::OpenDesktopW(lpszDesktop, dwFlags, fInherit, dwDesiredAccess)

#uselib "USER32.dll"
#func global OpenDesktopW "OpenDesktopW" wptr, wptr, wptr, wptr
; OpenDesktopW lpszDesktop, dwFlags, fInherit, dwDesiredAccess   ; 戻り値は stat
; lpszDesktop : LPCWSTR -> "wptr"
; dwFlags : DESKTOP_CONTROL_FLAGS -> "wptr"
; fInherit : BOOL -> "wptr"
; dwDesiredAccess : 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 "USER32.dll"
#cfunc global OpenDesktopW "OpenDesktopW" wstr, int, int, int
; res = OpenDesktopW(lpszDesktop, dwFlags, fInherit, dwDesiredAccess)
; lpszDesktop : LPCWSTR -> "wstr"
; dwFlags : DESKTOP_CONTROL_FLAGS -> "int"
; fInherit : BOOL -> "int"
; dwDesiredAccess : DWORD -> "int"

; HDESK OpenDesktopW(LPCWSTR lpszDesktop, DESKTOP_CONTROL_FLAGS dwFlags, BOOL fInherit, DWORD dwDesiredAccess)
#uselib "USER32.dll"
#cfunc global OpenDesktopW "OpenDesktopW" wstr, int, int, int
; res = OpenDesktopW(lpszDesktop, dwFlags, fInherit, dwDesiredAccess)
; lpszDesktop : LPCWSTR -> "wstr"
; dwFlags : DESKTOP_CONTROL_FLAGS -> "int"
; fInherit : BOOL -> "int"
; dwDesiredAccess : DWORD -> "int"

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

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procOpenDesktopW = user32.NewProc("OpenDesktopW")
)

// lpszDesktop (LPCWSTR), dwFlags (DESKTOP_CONTROL_FLAGS), fInherit (BOOL), dwDesiredAccess (DWORD)
r1, _, err := procOpenDesktopW.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpszDesktop))),
	uintptr(dwFlags),
	uintptr(fInherit),
	uintptr(dwDesiredAccess),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HDESK

function OpenDesktopW(
  lpszDesktop: PWideChar;   // LPCWSTR
  dwFlags: DWORD;   // DESKTOP_CONTROL_FLAGS
  fInherit: BOOL;   // BOOL
  dwDesiredAccess: DWORD   // DWORD
): THandle; stdcall;
  external 'USER32.dll' name 'OpenDesktopW';

result := DllCall("USER32\OpenDesktopW"
    , "WStr", lpszDesktop   ; LPCWSTR
    , "UInt", dwFlags   ; DESKTOP_CONTROL_FLAGS
    , "Int", fInherit   ; BOOL
    , "UInt", dwDesiredAccess   ; DWORD
    , "Ptr")   ; return: HDESK

●OpenDesktopW(lpszDesktop, dwFlags, fInherit, dwDesiredAccess) = DLL("USER32.dll", "void* OpenDesktopW(char*, dword, bool, dword)")
# 呼び出し: OpenDesktopW(lpszDesktop, dwFlags, fInherit, dwDesiredAccess)
# lpszDesktop : LPCWSTR -> "char*"
# dwFlags : DESKTOP_CONTROL_FLAGS -> "dword"
# fInherit : BOOL -> "bool"
# dwDesiredAccess : 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。