FoldStringW

// KERNEL32.dll  (Unicode / -W)
#include <windows.h>

INT FoldStringW(
    FOLD_STRING_MAP_FLAGS dwMapFlags,
    LPCWSTR lpSrcStr,
    INT cchSrc,
    LPWSTR lpDestStr,   // optional
    INT cchDest
);

<DllImport("KERNEL32.dll", CharSet:=CharSet.Unicode, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function FoldStringW(
    dwMapFlags As UInteger,   ' FOLD_STRING_MAP_FLAGS
    <MarshalAs(UnmanagedType.LPWStr)> lpSrcStr As String,   ' LPCWSTR
    cchSrc As Integer,   ' INT
    <MarshalAs(UnmanagedType.LPWStr)> lpDestStr As System.Text.StringBuilder,   ' LPWSTR optional, out
    cchDest As Integer   ' INT
) As Integer
End Function

' dwMapFlags : FOLD_STRING_MAP_FLAGS
' lpSrcStr : LPCWSTR
' cchSrc : INT
' lpDestStr : LPWSTR optional, out
' cchDest : INT
Declare PtrSafe Function FoldStringW Lib "kernel32" ( _
    ByVal dwMapFlags As Long, _
    ByVal lpSrcStr As LongPtr, _
    ByVal cchSrc As Long, _
    ByVal lpDestStr As LongPtr, _
    ByVal cchDest 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

FoldStringW = ctypes.windll.kernel32.FoldStringW
FoldStringW.restype = ctypes.c_int
FoldStringW.argtypes = [
    wintypes.DWORD,  # dwMapFlags : FOLD_STRING_MAP_FLAGS
    wintypes.LPCWSTR,  # lpSrcStr : LPCWSTR
    ctypes.c_int,  # cchSrc : INT
    wintypes.LPWSTR,  # lpDestStr : LPWSTR optional, out
    ctypes.c_int,  # cchDest : INT
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('KERNEL32.dll')
FoldStringW = Fiddle::Function.new(
  lib['FoldStringW'],
  [
    -Fiddle::TYPE_INT,  # dwMapFlags : FOLD_STRING_MAP_FLAGS
    Fiddle::TYPE_VOIDP,  # lpSrcStr : LPCWSTR
    Fiddle::TYPE_INT,  # cchSrc : INT
    Fiddle::TYPE_VOIDP,  # lpDestStr : LPWSTR optional, out
    Fiddle::TYPE_INT,  # cchDest : INT
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "kernel32")]
extern "system" {
    fn FoldStringW(
        dwMapFlags: u32,  // FOLD_STRING_MAP_FLAGS
        lpSrcStr: *const u16,  // LPCWSTR
        cchSrc: i32,  // INT
        lpDestStr: *mut u16,  // LPWSTR optional, out
        cchDest: i32  // INT
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("KERNEL32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern int FoldStringW(uint dwMapFlags, [MarshalAs(UnmanagedType.LPWStr)] string lpSrcStr, int cchSrc, [MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder lpDestStr, int cchDest);
"@
$api = Add-Type -MemberDefinition $sig -Name 'KERNEL32_FoldStringW' -Namespace Win32 -PassThru
# $api::FoldStringW(dwMapFlags, lpSrcStr, cchSrc, lpDestStr, cchDest)

#uselib "KERNEL32.dll"
#func global FoldStringW "FoldStringW" wptr, wptr, wptr, wptr, wptr
; FoldStringW dwMapFlags, lpSrcStr, cchSrc, varptr(lpDestStr), cchDest   ; 戻り値は stat
; dwMapFlags : FOLD_STRING_MAP_FLAGS -> "wptr"
; lpSrcStr : LPCWSTR -> "wptr"
; cchSrc : INT -> "wptr"
; lpDestStr : LPWSTR optional, out -> "wptr"
; cchDest : INT -> "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 "KERNEL32.dll"
#cfunc global FoldStringW "FoldStringW" int, wstr, int, var, int
; res = FoldStringW(dwMapFlags, lpSrcStr, cchSrc, lpDestStr, cchDest)
; dwMapFlags : FOLD_STRING_MAP_FLAGS -> "int"
; lpSrcStr : LPCWSTR -> "wstr"
; cchSrc : INT -> "int"
; lpDestStr : LPWSTR optional, out -> "var"
; cchDest : INT -> "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。

; INT FoldStringW(FOLD_STRING_MAP_FLAGS dwMapFlags, LPCWSTR lpSrcStr, INT cchSrc, LPWSTR lpDestStr, INT cchDest)
#uselib "KERNEL32.dll"
#cfunc global FoldStringW "FoldStringW" int, wstr, int, var, int
; res = FoldStringW(dwMapFlags, lpSrcStr, cchSrc, lpDestStr, cchDest)
; dwMapFlags : FOLD_STRING_MAP_FLAGS -> "int"
; lpSrcStr : LPCWSTR -> "wstr"
; cchSrc : INT -> "int"
; lpDestStr : LPWSTR optional, out -> "var"
; cchDest : INT -> "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 (
	kernel32 = windows.NewLazySystemDLL("KERNEL32.dll")
	procFoldStringW = kernel32.NewProc("FoldStringW")
)

// dwMapFlags (FOLD_STRING_MAP_FLAGS), lpSrcStr (LPCWSTR), cchSrc (INT), lpDestStr (LPWSTR optional, out), cchDest (INT)
r1, _, err := procFoldStringW.Call(
	uintptr(dwMapFlags),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(lpSrcStr))),
	uintptr(cchSrc),
	uintptr(lpDestStr),
	uintptr(cchDest),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function FoldStringW(
  dwMapFlags: DWORD;   // FOLD_STRING_MAP_FLAGS
  lpSrcStr: PWideChar;   // LPCWSTR
  cchSrc: Integer;   // INT
  lpDestStr: PWideChar;   // LPWSTR optional, out
  cchDest: Integer   // INT
): Integer; stdcall;
  external 'KERNEL32.dll' name 'FoldStringW';

result := DllCall("KERNEL32\FoldStringW"
    , "UInt", dwMapFlags   ; FOLD_STRING_MAP_FLAGS
    , "WStr", lpSrcStr   ; LPCWSTR
    , "Int", cchSrc   ; INT
    , "Ptr", lpDestStr   ; LPWSTR optional, out
    , "Int", cchDest   ; INT
    , "Int")   ; return: INT

●FoldStringW(dwMapFlags, lpSrcStr, cchSrc, lpDestStr, cchDest) = DLL("KERNEL32.dll", "int FoldStringW(dword, char*, int, char*, int)")
# 呼び出し: FoldStringW(dwMapFlags, lpSrcStr, cchSrc, lpDestStr, cchDest)
# dwMapFlags : FOLD_STRING_MAP_FLAGS -> "dword"
# lpSrcStr : LPCWSTR -> "char*"
# cchSrc : INT -> "int"
# lpDestStr : LPWSTR optional, out -> "char*"
# cchDest : 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)。
# ※-W(Unicode)関数。なでしこ1はANSIのため -A 版の利用を推奨。