SHGetSpecialFolderPathW

// SHELL32.dll  (Unicode / -W)
#include <windows.h>

BOOL SHGetSpecialFolderPathW(
    HWND hwnd,   // optional
    LPWSTR pszPath,
    INT csidl,
    BOOL fCreate
);

<DllImport("SHELL32.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function SHGetSpecialFolderPathW(
    hwnd As IntPtr,   ' HWND optional
    <MarshalAs(UnmanagedType.LPWStr)> pszPath As System.Text.StringBuilder,   ' LPWSTR out
    csidl As Integer,   ' INT
    fCreate As Boolean   ' BOOL
) As Boolean
End Function

' hwnd : HWND optional
' pszPath : LPWSTR out
' csidl : INT
' fCreate : BOOL
Declare PtrSafe Function SHGetSpecialFolderPathW Lib "shell32" ( _
    ByVal hwnd As LongPtr, _
    ByVal pszPath As LongPtr, _
    ByVal csidl As Long, _
    ByVal fCreate 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

SHGetSpecialFolderPathW = ctypes.windll.shell32.SHGetSpecialFolderPathW
SHGetSpecialFolderPathW.restype = wintypes.BOOL
SHGetSpecialFolderPathW.argtypes = [
    wintypes.HANDLE,  # hwnd : HWND optional
    wintypes.LPWSTR,  # pszPath : LPWSTR out
    ctypes.c_int,  # csidl : INT
    wintypes.BOOL,  # fCreate : BOOL
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SHELL32.dll')
SHGetSpecialFolderPathW = Fiddle::Function.new(
  lib['SHGetSpecialFolderPathW'],
  [
    Fiddle::TYPE_VOIDP,  # hwnd : HWND optional
    Fiddle::TYPE_VOIDP,  # pszPath : LPWSTR out
    Fiddle::TYPE_INT,  # csidl : INT
    Fiddle::TYPE_INT,  # fCreate : BOOL
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "shell32")]
extern "system" {
    fn SHGetSpecialFolderPathW(
        hwnd: *mut core::ffi::c_void,  // HWND optional
        pszPath: *mut u16,  // LPWSTR out
        csidl: i32,  // INT
        fCreate: i32  // BOOL
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("SHELL32.dll", CharSet = CharSet.Unicode)]
public static extern bool SHGetSpecialFolderPathW(IntPtr hwnd, [MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder pszPath, int csidl, bool fCreate);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SHELL32_SHGetSpecialFolderPathW' -Namespace Win32 -PassThru
# $api::SHGetSpecialFolderPathW(hwnd, pszPath, csidl, fCreate)

#uselib "SHELL32.dll"
#func global SHGetSpecialFolderPathW "SHGetSpecialFolderPathW" wptr, wptr, wptr, wptr
; SHGetSpecialFolderPathW hwnd, varptr(pszPath), csidl, fCreate   ; 戻り値は stat
; hwnd : HWND optional -> "wptr"
; pszPath : LPWSTR out -> "wptr"
; csidl : INT -> "wptr"
; fCreate : BOOL -> "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 "SHELL32.dll"
#cfunc global SHGetSpecialFolderPathW "SHGetSpecialFolderPathW" sptr, var, int, int
; res = SHGetSpecialFolderPathW(hwnd, pszPath, csidl, fCreate)
; hwnd : HWND optional -> "sptr"
; pszPath : LPWSTR out -> "var"
; csidl : INT -> "int"
; fCreate : BOOL -> "int"
; ※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 SHGetSpecialFolderPathW(HWND hwnd, LPWSTR pszPath, INT csidl, BOOL fCreate)
#uselib "SHELL32.dll"
#cfunc global SHGetSpecialFolderPathW "SHGetSpecialFolderPathW" intptr, var, int, int
; res = SHGetSpecialFolderPathW(hwnd, pszPath, csidl, fCreate)
; hwnd : HWND optional -> "intptr"
; pszPath : LPWSTR out -> "var"
; csidl : INT -> "int"
; fCreate : BOOL -> "int"
; ※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 (
	shell32 = windows.NewLazySystemDLL("SHELL32.dll")
	procSHGetSpecialFolderPathW = shell32.NewProc("SHGetSpecialFolderPathW")
)

// hwnd (HWND optional), pszPath (LPWSTR out), csidl (INT), fCreate (BOOL)
r1, _, err := procSHGetSpecialFolderPathW.Call(
	uintptr(hwnd),
	uintptr(pszPath),
	uintptr(csidl),
	uintptr(fCreate),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function SHGetSpecialFolderPathW(
  hwnd: THandle;   // HWND optional
  pszPath: PWideChar;   // LPWSTR out
  csidl: Integer;   // INT
  fCreate: BOOL   // BOOL
): BOOL; stdcall;
  external 'SHELL32.dll' name 'SHGetSpecialFolderPathW';

result := DllCall("SHELL32\SHGetSpecialFolderPathW"
    , "Ptr", hwnd   ; HWND optional
    , "Ptr", pszPath   ; LPWSTR out
    , "Int", csidl   ; INT
    , "Int", fCreate   ; BOOL
    , "Int")   ; return: BOOL

●SHGetSpecialFolderPathW(hwnd, pszPath, csidl, fCreate) = DLL("SHELL32.dll", "bool SHGetSpecialFolderPathW(void*, char*, int, bool)")
# 呼び出し: SHGetSpecialFolderPathW(hwnd, pszPath, csidl, fCreate)
# hwnd : HWND optional -> "void*"
# pszPath : LPWSTR out -> "char*"
# csidl : INT -> "int"
# fCreate : BOOL -> "bool"
# 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。