PathRelativePathToW

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

BOOL PathRelativePathToW(
    LPWSTR pszPath,
    LPCWSTR pszFrom,
    DWORD dwAttrFrom,
    LPCWSTR pszTo,
    DWORD dwAttrTo
);

<DllImport("SHLWAPI.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function PathRelativePathToW(
    <MarshalAs(UnmanagedType.LPWStr)> pszPath As System.Text.StringBuilder,   ' LPWSTR out
    <MarshalAs(UnmanagedType.LPWStr)> pszFrom As String,   ' LPCWSTR
    dwAttrFrom As UInteger,   ' DWORD
    <MarshalAs(UnmanagedType.LPWStr)> pszTo As String,   ' LPCWSTR
    dwAttrTo As UInteger   ' DWORD
) As Boolean
End Function

' pszPath : LPWSTR out
' pszFrom : LPCWSTR
' dwAttrFrom : DWORD
' pszTo : LPCWSTR
' dwAttrTo : DWORD
Declare PtrSafe Function PathRelativePathToW Lib "shlwapi" ( _
    ByVal pszPath As LongPtr, _
    ByVal pszFrom As LongPtr, _
    ByVal dwAttrFrom As Long, _
    ByVal pszTo As LongPtr, _
    ByVal dwAttrTo 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

PathRelativePathToW = ctypes.windll.shlwapi.PathRelativePathToW
PathRelativePathToW.restype = wintypes.BOOL
PathRelativePathToW.argtypes = [
    wintypes.LPWSTR,  # pszPath : LPWSTR out
    wintypes.LPCWSTR,  # pszFrom : LPCWSTR
    wintypes.DWORD,  # dwAttrFrom : DWORD
    wintypes.LPCWSTR,  # pszTo : LPCWSTR
    wintypes.DWORD,  # dwAttrTo : DWORD
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SHLWAPI.dll')
PathRelativePathToW = Fiddle::Function.new(
  lib['PathRelativePathToW'],
  [
    Fiddle::TYPE_VOIDP,  # pszPath : LPWSTR out
    Fiddle::TYPE_VOIDP,  # pszFrom : LPCWSTR
    -Fiddle::TYPE_INT,  # dwAttrFrom : DWORD
    Fiddle::TYPE_VOIDP,  # pszTo : LPCWSTR
    -Fiddle::TYPE_INT,  # dwAttrTo : DWORD
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "shlwapi")]
extern "system" {
    fn PathRelativePathToW(
        pszPath: *mut u16,  // LPWSTR out
        pszFrom: *const u16,  // LPCWSTR
        dwAttrFrom: u32,  // DWORD
        pszTo: *const u16,  // LPCWSTR
        dwAttrTo: u32  // DWORD
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("SHLWAPI.dll", CharSet = CharSet.Unicode)]
public static extern bool PathRelativePathToW([MarshalAs(UnmanagedType.LPWStr)] System.Text.StringBuilder pszPath, [MarshalAs(UnmanagedType.LPWStr)] string pszFrom, uint dwAttrFrom, [MarshalAs(UnmanagedType.LPWStr)] string pszTo, uint dwAttrTo);
"@
$api = Add-Type -MemberDefinition $sig -Name 'SHLWAPI_PathRelativePathToW' -Namespace Win32 -PassThru
# $api::PathRelativePathToW(pszPath, pszFrom, dwAttrFrom, pszTo, dwAttrTo)

#uselib "SHLWAPI.dll"
#func global PathRelativePathToW "PathRelativePathToW" wptr, wptr, wptr, wptr, wptr
; PathRelativePathToW varptr(pszPath), pszFrom, dwAttrFrom, pszTo, dwAttrTo   ; 戻り値は stat
; pszPath : LPWSTR out -> "wptr"
; pszFrom : LPCWSTR -> "wptr"
; dwAttrFrom : DWORD -> "wptr"
; pszTo : LPCWSTR -> "wptr"
; dwAttrTo : 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 "SHLWAPI.dll"
#cfunc global PathRelativePathToW "PathRelativePathToW" var, wstr, int, wstr, int
; res = PathRelativePathToW(pszPath, pszFrom, dwAttrFrom, pszTo, dwAttrTo)
; pszPath : LPWSTR out -> "var"
; pszFrom : LPCWSTR -> "wstr"
; dwAttrFrom : DWORD -> "int"
; pszTo : LPCWSTR -> "wstr"
; dwAttrTo : 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。

; BOOL PathRelativePathToW(LPWSTR pszPath, LPCWSTR pszFrom, DWORD dwAttrFrom, LPCWSTR pszTo, DWORD dwAttrTo)
#uselib "SHLWAPI.dll"
#cfunc global PathRelativePathToW "PathRelativePathToW" var, wstr, int, wstr, int
; res = PathRelativePathToW(pszPath, pszFrom, dwAttrFrom, pszTo, dwAttrTo)
; pszPath : LPWSTR out -> "var"
; pszFrom : LPCWSTR -> "wstr"
; dwAttrFrom : DWORD -> "int"
; pszTo : LPCWSTR -> "wstr"
; dwAttrTo : 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")
	procPathRelativePathToW = shlwapi.NewProc("PathRelativePathToW")
)

// pszPath (LPWSTR out), pszFrom (LPCWSTR), dwAttrFrom (DWORD), pszTo (LPCWSTR), dwAttrTo (DWORD)
r1, _, err := procPathRelativePathToW.Call(
	uintptr(pszPath),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(pszFrom))),
	uintptr(dwAttrFrom),
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(pszTo))),
	uintptr(dwAttrTo),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function PathRelativePathToW(
  pszPath: PWideChar;   // LPWSTR out
  pszFrom: PWideChar;   // LPCWSTR
  dwAttrFrom: DWORD;   // DWORD
  pszTo: PWideChar;   // LPCWSTR
  dwAttrTo: DWORD   // DWORD
): BOOL; stdcall;
  external 'SHLWAPI.dll' name 'PathRelativePathToW';

result := DllCall("SHLWAPI\PathRelativePathToW"
    , "Ptr", pszPath   ; LPWSTR out
    , "WStr", pszFrom   ; LPCWSTR
    , "UInt", dwAttrFrom   ; DWORD
    , "WStr", pszTo   ; LPCWSTR
    , "UInt", dwAttrTo   ; DWORD
    , "Int")   ; return: BOOL

●PathRelativePathToW(pszPath, pszFrom, dwAttrFrom, pszTo, dwAttrTo) = DLL("SHLWAPI.dll", "bool PathRelativePathToW(char*, char*, dword, char*, dword)")
# 呼び出し: PathRelativePathToW(pszPath, pszFrom, dwAttrFrom, pszTo, dwAttrTo)
# pszPath : LPWSTR out -> "char*"
# pszFrom : LPCWSTR -> "char*"
# dwAttrFrom : DWORD -> "dword"
# pszTo : LPCWSTR -> "char*"
# dwAttrTo : 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。