GetDiskSpaceInformationW

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

HRESULT GetDiskSpaceInformationW(
    LPCWSTR rootPath,   // optional
    DISK_SPACE_INFORMATION* diskSpaceInfo
);

<DllImport("KERNEL32.dll", CharSet:=CharSet.Unicode, ExactSpelling:=True)>
Public Shared Function GetDiskSpaceInformationW(
    <MarshalAs(UnmanagedType.LPWStr)> rootPath As String,   ' LPCWSTR optional
    diskSpaceInfo As IntPtr   ' DISK_SPACE_INFORMATION* out
) As Integer
End Function

' rootPath : LPCWSTR optional
' diskSpaceInfo : DISK_SPACE_INFORMATION* out
Declare PtrSafe Function GetDiskSpaceInformationW Lib "kernel32" ( _
    ByVal rootPath As LongPtr, _
    ByVal diskSpaceInfo As LongPtr) 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

GetDiskSpaceInformationW = ctypes.windll.kernel32.GetDiskSpaceInformationW
GetDiskSpaceInformationW.restype = ctypes.c_int
GetDiskSpaceInformationW.argtypes = [
    wintypes.LPCWSTR,  # rootPath : LPCWSTR optional
    ctypes.c_void_p,  # diskSpaceInfo : DISK_SPACE_INFORMATION* out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('KERNEL32.dll')
GetDiskSpaceInformationW = Fiddle::Function.new(
  lib['GetDiskSpaceInformationW'],
  [
    Fiddle::TYPE_VOIDP,  # rootPath : LPCWSTR optional
    Fiddle::TYPE_VOIDP,  # diskSpaceInfo : DISK_SPACE_INFORMATION* out
  ],
  Fiddle::TYPE_INT)
# Wide strings: pass str.encode("UTF-16LE") + "\x00\x00"

#[link(name = "kernel32")]
extern "system" {
    fn GetDiskSpaceInformationW(
        rootPath: *const u16,  // LPCWSTR optional
        diskSpaceInfo: *mut DISK_SPACE_INFORMATION  // DISK_SPACE_INFORMATION* out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("KERNEL32.dll", CharSet = CharSet.Unicode)]
public static extern int GetDiskSpaceInformationW([MarshalAs(UnmanagedType.LPWStr)] string rootPath, IntPtr diskSpaceInfo);
"@
$api = Add-Type -MemberDefinition $sig -Name 'KERNEL32_GetDiskSpaceInformationW' -Namespace Win32 -PassThru
# $api::GetDiskSpaceInformationW(rootPath, diskSpaceInfo)

#uselib "KERNEL32.dll"
#func global GetDiskSpaceInformationW "GetDiskSpaceInformationW" wptr, wptr
; GetDiskSpaceInformationW rootPath, varptr(diskSpaceInfo)   ; 戻り値は stat
; rootPath : LPCWSTR optional -> "wptr"
; diskSpaceInfo : DISK_SPACE_INFORMATION* out -> "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 GetDiskSpaceInformationW "GetDiskSpaceInformationW" wstr, var
; res = GetDiskSpaceInformationW(rootPath, diskSpaceInfo)
; rootPath : LPCWSTR optional -> "wstr"
; diskSpaceInfo : DISK_SPACE_INFORMATION* out -> "var"
; ※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 GetDiskSpaceInformationW(LPCWSTR rootPath, DISK_SPACE_INFORMATION* diskSpaceInfo)
#uselib "KERNEL32.dll"
#cfunc global GetDiskSpaceInformationW "GetDiskSpaceInformationW" wstr, var
; res = GetDiskSpaceInformationW(rootPath, diskSpaceInfo)
; rootPath : LPCWSTR optional -> "wstr"
; diskSpaceInfo : DISK_SPACE_INFORMATION* out -> "var"
; ※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")
	procGetDiskSpaceInformationW = kernel32.NewProc("GetDiskSpaceInformationW")
)

// rootPath (LPCWSTR optional), diskSpaceInfo (DISK_SPACE_INFORMATION* out)
r1, _, err := procGetDiskSpaceInformationW.Call(
	uintptr(unsafe.Pointer(windows.StringToUTF16Ptr(rootPath))),
	uintptr(diskSpaceInfo),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function GetDiskSpaceInformationW(
  rootPath: PWideChar;   // LPCWSTR optional
  diskSpaceInfo: Pointer   // DISK_SPACE_INFORMATION* out
): Integer; stdcall;
  external 'KERNEL32.dll' name 'GetDiskSpaceInformationW';

result := DllCall("KERNEL32\GetDiskSpaceInformationW"
    , "WStr", rootPath   ; LPCWSTR optional
    , "Ptr", diskSpaceInfo   ; DISK_SPACE_INFORMATION* out
    , "Int")   ; return: HRESULT

●GetDiskSpaceInformationW(rootPath, diskSpaceInfo) = DLL("KERNEL32.dll", "int GetDiskSpaceInformationW(char*, void*)")
# 呼び出し: GetDiskSpaceInformationW(rootPath, diskSpaceInfo)
# rootPath : LPCWSTR optional -> "char*"
# diskSpaceInfo : DISK_SPACE_INFORMATION* out -> "void*"
# 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。