StrRetToBufA

// SHLWAPI.dll  (ANSI / -A)
#include <windows.h>

HRESULT StrRetToBufA(
    STRRET* pstr,
    ITEMIDLIST* pidl,   // optional
    LPSTR pszBuf,
    DWORD cchBuf
);

<DllImport("SHLWAPI.dll", CharSet:=CharSet.Ansi, ExactSpelling:=True)>
Public Shared Function StrRetToBufA(
    pstr As IntPtr,   ' STRRET* in/out
    pidl As IntPtr,   ' ITEMIDLIST* optional
    <MarshalAs(UnmanagedType.LPStr)> pszBuf As System.Text.StringBuilder,   ' LPSTR out
    cchBuf As UInteger   ' DWORD
) As Integer
End Function

' pstr : STRRET* in/out
' pidl : ITEMIDLIST* optional
' pszBuf : LPSTR out
' cchBuf : DWORD
Declare PtrSafe Function StrRetToBufA Lib "shlwapi" ( _
    ByVal pstr As LongPtr, _
    ByVal pidl As LongPtr, _
    ByVal pszBuf As String, _
    ByVal cchBuf As Long) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

StrRetToBufA = ctypes.windll.shlwapi.StrRetToBufA
StrRetToBufA.restype = ctypes.c_int
StrRetToBufA.argtypes = [
    ctypes.c_void_p,  # pstr : STRRET* in/out
    ctypes.c_void_p,  # pidl : ITEMIDLIST* optional
    wintypes.LPSTR,  # pszBuf : LPSTR out
    wintypes.DWORD,  # cchBuf : DWORD
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SHLWAPI.dll')
StrRetToBufA = Fiddle::Function.new(
  lib['StrRetToBufA'],
  [
    Fiddle::TYPE_VOIDP,  # pstr : STRRET* in/out
    Fiddle::TYPE_VOIDP,  # pidl : ITEMIDLIST* optional
    Fiddle::TYPE_VOIDP,  # pszBuf : LPSTR out
    -Fiddle::TYPE_INT,  # cchBuf : DWORD
  ],
  Fiddle::TYPE_INT)

#[link(name = "shlwapi")]
extern "system" {
    fn StrRetToBufA(
        pstr: *mut STRRET,  // STRRET* in/out
        pidl: *mut ITEMIDLIST,  // ITEMIDLIST* optional
        pszBuf: *mut u8,  // LPSTR out
        cchBuf: u32  // DWORD
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("SHLWAPI.dll", CharSet = CharSet.Ansi)]
public static extern int StrRetToBufA(IntPtr pstr, IntPtr pidl, [MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder pszBuf, uint cchBuf);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SHLWAPI_StrRetToBufA' -Namespace Win32 -PassThru
# $api::StrRetToBufA(pstr, pidl, pszBuf, cchBuf)

#uselib "SHLWAPI.dll"
#func global StrRetToBufA "StrRetToBufA" sptr, sptr, sptr, sptr
; StrRetToBufA varptr(pstr), varptr(pidl), varptr(pszBuf), cchBuf   ; 戻り値は stat
; pstr : STRRET* in/out -> "sptr"
; pidl : ITEMIDLIST* optional -> "sptr"
; pszBuf : LPSTR out -> "sptr"
; cchBuf : DWORD -> "sptr"
; ※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 StrRetToBufA "StrRetToBufA" var, var, var, int
; res = StrRetToBufA(pstr, pidl, pszBuf, cchBuf)
; pstr : STRRET* in/out -> "var"
; pidl : ITEMIDLIST* optional -> "var"
; pszBuf : LPSTR out -> "var"
; cchBuf : DWORD -> "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。

; HRESULT StrRetToBufA(STRRET* pstr, ITEMIDLIST* pidl, LPSTR pszBuf, DWORD cchBuf)
#uselib "SHLWAPI.dll"
#cfunc global StrRetToBufA "StrRetToBufA" var, var, var, int
; res = StrRetToBufA(pstr, pidl, pszBuf, cchBuf)
; pstr : STRRET* in/out -> "var"
; pidl : ITEMIDLIST* optional -> "var"
; pszBuf : LPSTR out -> "var"
; cchBuf : DWORD -> "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")
	procStrRetToBufA = shlwapi.NewProc("StrRetToBufA")
)

// pstr (STRRET* in/out), pidl (ITEMIDLIST* optional), pszBuf (LPSTR out), cchBuf (DWORD)
r1, _, err := procStrRetToBufA.Call(
	uintptr(pstr),
	uintptr(pidl),
	uintptr(pszBuf),
	uintptr(cchBuf),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function StrRetToBufA(
  pstr: Pointer;   // STRRET* in/out
  pidl: Pointer;   // ITEMIDLIST* optional
  pszBuf: PAnsiChar;   // LPSTR out
  cchBuf: DWORD   // DWORD
): Integer; stdcall;
  external 'SHLWAPI.dll' name 'StrRetToBufA';

result := DllCall("SHLWAPI\StrRetToBufA"
    , "Ptr", pstr   ; STRRET* in/out
    , "Ptr", pidl   ; ITEMIDLIST* optional
    , "Ptr", pszBuf   ; LPSTR out
    , "UInt", cchBuf   ; DWORD
    , "Int")   ; return: HRESULT

●StrRetToBufA(pstr, pidl, pszBuf, cchBuf) = DLL("SHLWAPI.dll", "int StrRetToBufA(void*, void*, char*, dword)")
# 呼び出し: StrRetToBufA(pstr, pidl, pszBuf, cchBuf)
# pstr : STRRET* in/out -> "void*"
# pidl : ITEMIDLIST* optional -> "void*"
# pszBuf : LPSTR out -> "char*"
# cchBuf : 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)。