StrFormatByteSizeA

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

LPSTR StrFormatByteSizeA(
    DWORD dw,
    LPSTR pszBuf,
    DWORD cchBuf
);

<DllImport("SHLWAPI.dll", CharSet:=CharSet.Ansi, ExactSpelling:=True)>
Public Shared Function StrFormatByteSizeA(
    dw As UInteger,   ' DWORD
    <MarshalAs(UnmanagedType.LPStr)> pszBuf As System.Text.StringBuilder,   ' LPSTR out
    cchBuf As UInteger   ' DWORD
) As IntPtr
End Function

' dw : DWORD
' pszBuf : LPSTR out
' cchBuf : DWORD
Declare PtrSafe Function StrFormatByteSizeA Lib "shlwapi" ( _
    ByVal dw As Long, _
    ByVal pszBuf As String, _
    ByVal cchBuf As Long) As LongPtr
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

StrFormatByteSizeA = ctypes.windll.shlwapi.StrFormatByteSizeA
StrFormatByteSizeA.restype = wintypes.LPSTR
StrFormatByteSizeA.argtypes = [
    wintypes.DWORD,  # dw : DWORD
    wintypes.LPSTR,  # pszBuf : LPSTR out
    wintypes.DWORD,  # cchBuf : DWORD
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('SHLWAPI.dll')
StrFormatByteSizeA = Fiddle::Function.new(
  lib['StrFormatByteSizeA'],
  [
    -Fiddle::TYPE_INT,  # dw : DWORD
    Fiddle::TYPE_VOIDP,  # pszBuf : LPSTR out
    -Fiddle::TYPE_INT,  # cchBuf : DWORD
  ],
  Fiddle::TYPE_VOIDP)

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

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

#uselib "SHLWAPI.dll"
#func global StrFormatByteSizeA "StrFormatByteSizeA" sptr, sptr, sptr
; StrFormatByteSizeA dw, varptr(pszBuf), cchBuf   ; 戻り値は stat
; dw : DWORD -> "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 StrFormatByteSizeA "StrFormatByteSizeA" int, var, int
; res = StrFormatByteSizeA(dw, pszBuf, cchBuf)
; dw : DWORD -> "int"
; 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。

; LPSTR StrFormatByteSizeA(DWORD dw, LPSTR pszBuf, DWORD cchBuf)
#uselib "SHLWAPI.dll"
#cfunc global StrFormatByteSizeA "StrFormatByteSizeA" int, var, int
; res = StrFormatByteSizeA(dw, pszBuf, cchBuf)
; dw : DWORD -> "int"
; 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")
	procStrFormatByteSizeA = shlwapi.NewProc("StrFormatByteSizeA")
)

// dw (DWORD), pszBuf (LPSTR out), cchBuf (DWORD)
r1, _, err := procStrFormatByteSizeA.Call(
	uintptr(dw),
	uintptr(pszBuf),
	uintptr(cchBuf),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // LPSTR

function StrFormatByteSizeA(
  dw: DWORD;   // DWORD
  pszBuf: PAnsiChar;   // LPSTR out
  cchBuf: DWORD   // DWORD
): PAnsiChar; stdcall;
  external 'SHLWAPI.dll' name 'StrFormatByteSizeA';

result := DllCall("SHLWAPI\StrFormatByteSizeA"
    , "UInt", dw   ; DWORD
    , "Ptr", pszBuf   ; LPSTR out
    , "UInt", cchBuf   ; DWORD
    , "Ptr")   ; return: LPSTR

●StrFormatByteSizeA(dw, pszBuf, cchBuf) = DLL("SHLWAPI.dll", "char* StrFormatByteSizeA(dword, char*, dword)")
# 呼び出し: StrFormatByteSizeA(dw, pszBuf, cchBuf)
# dw : DWORD -> "dword"
# 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)。