CharLowerBuffA

// USER32.dll  (ANSI / -A)
#include <windows.h>

DWORD CharLowerBuffA(
    LPSTR lpsz,
    DWORD cchLength
);

<DllImport("USER32.dll", CharSet:=CharSet.Ansi, ExactSpelling:=True)>
Public Shared Function CharLowerBuffA(
    <MarshalAs(UnmanagedType.LPStr)> lpsz As System.Text.StringBuilder,   ' LPSTR in/out
    cchLength As UInteger   ' DWORD
) As UInteger
End Function

' lpsz : LPSTR in/out
' cchLength : DWORD
Declare PtrSafe Function CharLowerBuffA Lib "user32" ( _
    ByVal lpsz As String, _
    ByVal cchLength 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

CharLowerBuffA = ctypes.windll.user32.CharLowerBuffA
CharLowerBuffA.restype = wintypes.DWORD
CharLowerBuffA.argtypes = [
    wintypes.LPSTR,  # lpsz : LPSTR in/out
    wintypes.DWORD,  # cchLength : DWORD
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
CharLowerBuffA = Fiddle::Function.new(
  lib['CharLowerBuffA'],
  [
    Fiddle::TYPE_VOIDP,  # lpsz : LPSTR in/out
    -Fiddle::TYPE_INT,  # cchLength : DWORD
  ],
  -Fiddle::TYPE_INT)

#[link(name = "user32")]
extern "system" {
    fn CharLowerBuffA(
        lpsz: *mut u8,  // LPSTR in/out
        cchLength: u32  // DWORD
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Ansi)]
public static extern uint CharLowerBuffA([MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder lpsz, uint cchLength);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_CharLowerBuffA' -Namespace Win32 -PassThru
# $api::CharLowerBuffA(lpsz, cchLength)

#uselib "USER32.dll"
#func global CharLowerBuffA "CharLowerBuffA" sptr, sptr
; CharLowerBuffA varptr(lpsz), cchLength   ; 戻り値は stat
; lpsz : LPSTR in/out -> "sptr"
; cchLength : 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 "USER32.dll"
#cfunc global CharLowerBuffA "CharLowerBuffA" var, int
; res = CharLowerBuffA(lpsz, cchLength)
; lpsz : LPSTR in/out -> "var"
; cchLength : 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。

; DWORD CharLowerBuffA(LPSTR lpsz, DWORD cchLength)
#uselib "USER32.dll"
#cfunc global CharLowerBuffA "CharLowerBuffA" var, int
; res = CharLowerBuffA(lpsz, cchLength)
; lpsz : LPSTR in/out -> "var"
; cchLength : 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 (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procCharLowerBuffA = user32.NewProc("CharLowerBuffA")
)

// lpsz (LPSTR in/out), cchLength (DWORD)
r1, _, err := procCharLowerBuffA.Call(
	uintptr(lpsz),
	uintptr(cchLength),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function CharLowerBuffA(
  lpsz: PAnsiChar;   // LPSTR in/out
  cchLength: DWORD   // DWORD
): DWORD; stdcall;
  external 'USER32.dll' name 'CharLowerBuffA';

result := DllCall("USER32\CharLowerBuffA"
    , "Ptr", lpsz   ; LPSTR in/out
    , "UInt", cchLength   ; DWORD
    , "UInt")   ; return: DWORD

●CharLowerBuffA(lpsz, cchLength) = DLL("USER32.dll", "dword CharLowerBuffA(char*, dword)")
# 呼び出し: CharLowerBuffA(lpsz, cchLength)
# lpsz : LPSTR in/out -> "char*"
# cchLength : 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)。