StrCatBuffW

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

LPWSTR StrCatBuffW(
    LPWSTR pszDest,
    LPCWSTR pszSrc,
    INT cchDestBuffSize
);

<DllImport("SHLWAPI.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function StrCatBuffW(
    <MarshalAs(UnmanagedType.LPWStr)> pszDest As System.Text.StringBuilder,   ' LPWSTR in/out
    <MarshalAs(UnmanagedType.LPWStr)> pszSrc As String,   ' LPCWSTR
    cchDestBuffSize As Integer   ' INT
) As IntPtr
End Function

' pszDest : LPWSTR in/out
' pszSrc : LPCWSTR
' cchDestBuffSize : INT
Declare PtrSafe Function StrCatBuffW Lib "shlwapi" ( _
    ByVal pszDest As LongPtr, _
    ByVal pszSrc As LongPtr, _
    ByVal cchDestBuffSize 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

StrCatBuffW = ctypes.windll.shlwapi.StrCatBuffW
StrCatBuffW.restype = wintypes.LPWSTR
StrCatBuffW.argtypes = [
    wintypes.LPWSTR,  # pszDest : LPWSTR in/out
    wintypes.LPCWSTR,  # pszSrc : LPCWSTR
    ctypes.c_int,  # cchDestBuffSize : INT
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SHLWAPI.dll')
StrCatBuffW = Fiddle::Function.new(
  lib['StrCatBuffW'],
  [
    Fiddle::TYPE_VOIDP,  # pszDest : LPWSTR in/out
    Fiddle::TYPE_VOIDP,  # pszSrc : LPCWSTR
    Fiddle::TYPE_INT,  # cchDestBuffSize : INT
  ],
  Fiddle::TYPE_VOIDP)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "shlwapi")]
extern "system" {
    fn StrCatBuffW(
        pszDest: *mut u16,  // LPWSTR in/out
        pszSrc: *const u16,  // LPCWSTR
        cchDestBuffSize: i32  // INT
    ) -> *mut u16;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("SHLWAPI.dll", CharSet = CharSet.Unicode)]
public static extern IntPtr StrCatBuffW([MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder pszDest, [MarshalAs(UnmanagedType.LPWStr)] string pszSrc, int cchDestBuffSize);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SHLWAPI_StrCatBuffW' -Namespace Win32 -PassThru
# $api::StrCatBuffW(pszDest, pszSrc, cchDestBuffSize)

#uselib "SHLWAPI.dll"
#func global StrCatBuffW "StrCatBuffW" wptr, wptr, wptr
; StrCatBuffW varptr(pszDest), pszSrc, cchDestBuffSize   ; 戻り値は stat
; pszDest : LPWSTR in/out -> "wptr"
; pszSrc : LPCWSTR -> "wptr"
; cchDestBuffSize : 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 "SHLWAPI.dll"
#cfunc global StrCatBuffW "StrCatBuffW" var, wstr, int
; res = StrCatBuffW(pszDest, pszSrc, cchDestBuffSize)
; pszDest : LPWSTR in/out -> "var"
; pszSrc : LPCWSTR -> "wstr"
; cchDestBuffSize : 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。

; LPWSTR StrCatBuffW(LPWSTR pszDest, LPCWSTR pszSrc, INT cchDestBuffSize)
#uselib "SHLWAPI.dll"
#cfunc global StrCatBuffW "StrCatBuffW" var, wstr, int
; res = StrCatBuffW(pszDest, pszSrc, cchDestBuffSize)
; pszDest : LPWSTR in/out -> "var"
; pszSrc : LPCWSTR -> "wstr"
; cchDestBuffSize : 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 (
	shlwapi = windows.NewLazySystemDLL("SHLWAPI.dll")
	procStrCatBuffW = shlwapi.NewProc("StrCatBuffW")
)

// pszDest (LPWSTR in/out), pszSrc (LPCWSTR), cchDestBuffSize (INT)
r1, _, err := procStrCatBuffW.Call(
	uintptr(pszDest),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(pszSrc))),
	uintptr(cchDestBuffSize),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // LPWSTR

function StrCatBuffW(
  pszDest: PWideChar;   // LPWSTR in/out
  pszSrc: PWideChar;   // LPCWSTR
  cchDestBuffSize: Integer   // INT
): PWideChar; stdcall;
  external 'SHLWAPI.dll' name 'StrCatBuffW';

result := DllCall("SHLWAPI\StrCatBuffW"
    , "Ptr", pszDest   ; LPWSTR in/out
    , "WStr", pszSrc   ; LPCWSTR
    , "Int", cchDestBuffSize   ; INT
    , "Ptr")   ; return: LPWSTR

●StrCatBuffW(pszDest, pszSrc, cchDestBuffSize) = DLL("SHLWAPI.dll", "char* StrCatBuffW(char*, char*, int)")
# 呼び出し: StrCatBuffW(pszDest, pszSrc, cchDestBuffSize)
# pszDest : LPWSTR in/out -> "char*"
# pszSrc : LPCWSTR -> "char*"
# cchDestBuffSize : 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。