GetWindowTextLengthA

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

INT GetWindowTextLengthA(
    HWND hWnd
);

<DllImport("USER32.dll", CharSet:=CharSet.Ansi, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetWindowTextLengthA(
    hWnd As IntPtr   ' HWND
) As Integer
End Function

' hWnd : HWND
Declare PtrSafe Function GetWindowTextLengthA Lib "user32" ( _
    ByVal hWnd As LongPtr) As Long
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

GetWindowTextLengthA = ctypes.windll.user32.GetWindowTextLengthA
GetWindowTextLengthA.restype = ctypes.c_int
GetWindowTextLengthA.argtypes = [
    wintypes.HANDLE,  # hWnd : HWND
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
GetWindowTextLengthA = Fiddle::Function.new(
  lib['GetWindowTextLengthA'],
  [
    Fiddle::TYPE_VOIDP,  # hWnd : HWND
  ],
  Fiddle::TYPE_INT)

#[link(name = "user32")]
extern "system" {
    fn GetWindowTextLengthA(
        hWnd: *mut core::ffi::c_void  // HWND
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Ansi, SetLastError = true)]
public static extern int GetWindowTextLengthA(IntPtr hWnd);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_GetWindowTextLengthA' -Namespace Win32 -PassThru
# $api::GetWindowTextLengthA(hWnd)

#uselib "USER32.dll"
#func global GetWindowTextLengthA "GetWindowTextLengthA" sptr
; GetWindowTextLengthA hWnd   ; 戻り値は stat
; hWnd : HWND -> "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 GetWindowTextLengthA "GetWindowTextLengthA" sptr
; res = GetWindowTextLengthA(hWnd)
; hWnd : HWND -> "sptr"

; INT GetWindowTextLengthA(HWND hWnd)
#uselib "USER32.dll"
#cfunc global GetWindowTextLengthA "GetWindowTextLengthA" intptr
; res = GetWindowTextLengthA(hWnd)
; hWnd : HWND -> "intptr"

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	user32 = windows.NewLazySystemDLL("USER32.dll")
	procGetWindowTextLengthA = user32.NewProc("GetWindowTextLengthA")
)

// hWnd (HWND)
r1, _, err := procGetWindowTextLengthA.Call(
	uintptr(hWnd),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // INT

function GetWindowTextLengthA(
  hWnd: THandle   // HWND
): Integer; stdcall;
  external 'USER32.dll' name 'GetWindowTextLengthA';

result := DllCall("USER32\GetWindowTextLengthA"
    , "Ptr", hWnd   ; HWND
    , "Int")   ; return: INT

●GetWindowTextLengthA(hWnd) = DLL("USER32.dll", "int GetWindowTextLengthA(void*)")
# 呼び出し: GetWindowTextLengthA(hWnd)
# hWnd : HWND -> "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)。