GetDlgItemTextA

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

DWORD GetDlgItemTextA(
    HWND hDlg,
    INT nIDDlgItem,
    LPSTR lpString,
    INT cchMax
);

<DllImport("USER32.dll", CharSet:=CharSet.Ansi, SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetDlgItemTextA(
    hDlg As IntPtr,   ' HWND
    nIDDlgItem As Integer,   ' INT
    <MarshalAs(UnmanagedType.LPStr)> lpString As System.Text.StringBuilder,   ' LPSTR out
    cchMax As Integer   ' INT
) As UInteger
End Function

' hDlg : HWND
' nIDDlgItem : INT
' lpString : LPSTR out
' cchMax : INT
Declare PtrSafe Function GetDlgItemTextA Lib "user32" ( _
    ByVal hDlg As LongPtr, _
    ByVal nIDDlgItem As Long, _
    ByVal lpString As String, _
    ByVal cchMax 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

GetDlgItemTextA = ctypes.windll.user32.GetDlgItemTextA
GetDlgItemTextA.restype = wintypes.DWORD
GetDlgItemTextA.argtypes = [
    wintypes.HANDLE,  # hDlg : HWND
    ctypes.c_int,  # nIDDlgItem : INT
    wintypes.LPSTR,  # lpString : LPSTR out
    ctypes.c_int,  # cchMax : INT
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('USER32.dll')
GetDlgItemTextA = Fiddle::Function.new(
  lib['GetDlgItemTextA'],
  [
    Fiddle::TYPE_VOIDP,  # hDlg : HWND
    Fiddle::TYPE_INT,  # nIDDlgItem : INT
    Fiddle::TYPE_VOIDP,  # lpString : LPSTR out
    Fiddle::TYPE_INT,  # cchMax : INT
  ],
  -Fiddle::TYPE_INT)

#[link(name = "user32")]
extern "system" {
    fn GetDlgItemTextA(
        hDlg: *mut core::ffi::c_void,  // HWND
        nIDDlgItem: i32,  // INT
        lpString: *mut u8,  // LPSTR out
        cchMax: i32  // INT
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("USER32.dll", CharSet = CharSet.Ansi, SetLastError = true)]
public static extern uint GetDlgItemTextA(IntPtr hDlg, int nIDDlgItem, [MarshalAs(UnmanagedType.LPStr)] System.Text.StringBuilder lpString, int cchMax);
"@
$api = Add-Type -MemberDefinition $sig -Name 'USER32_GetDlgItemTextA' -Namespace Win32 -PassThru
# $api::GetDlgItemTextA(hDlg, nIDDlgItem, lpString, cchMax)

#uselib "USER32.dll"
#func global GetDlgItemTextA "GetDlgItemTextA" sptr, sptr, sptr, sptr
; GetDlgItemTextA hDlg, nIDDlgItem, varptr(lpString), cchMax   ; 戻り値は stat
; hDlg : HWND -> "sptr"
; nIDDlgItem : INT -> "sptr"
; lpString : LPSTR out -> "sptr"
; cchMax : INT -> "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 GetDlgItemTextA "GetDlgItemTextA" sptr, int, var, int
; res = GetDlgItemTextA(hDlg, nIDDlgItem, lpString, cchMax)
; hDlg : HWND -> "sptr"
; nIDDlgItem : INT -> "int"
; lpString : LPSTR out -> "var"
; cchMax : INT -> "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 GetDlgItemTextA(HWND hDlg, INT nIDDlgItem, LPSTR lpString, INT cchMax)
#uselib "USER32.dll"
#cfunc global GetDlgItemTextA "GetDlgItemTextA" intptr, int, var, int
; res = GetDlgItemTextA(hDlg, nIDDlgItem, lpString, cchMax)
; hDlg : HWND -> "intptr"
; nIDDlgItem : INT -> "int"
; lpString : LPSTR out -> "var"
; cchMax : INT -> "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")
	procGetDlgItemTextA = user32.NewProc("GetDlgItemTextA")
)

// hDlg (HWND), nIDDlgItem (INT), lpString (LPSTR out), cchMax (INT)
r1, _, err := procGetDlgItemTextA.Call(
	uintptr(hDlg),
	uintptr(nIDDlgItem),
	uintptr(lpString),
	uintptr(cchMax),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function GetDlgItemTextA(
  hDlg: THandle;   // HWND
  nIDDlgItem: Integer;   // INT
  lpString: PAnsiChar;   // LPSTR out
  cchMax: Integer   // INT
): DWORD; stdcall;
  external 'USER32.dll' name 'GetDlgItemTextA';

result := DllCall("USER32\GetDlgItemTextA"
    , "Ptr", hDlg   ; HWND
    , "Int", nIDDlgItem   ; INT
    , "Ptr", lpString   ; LPSTR out
    , "Int", cchMax   ; INT
    , "UInt")   ; return: DWORD

●GetDlgItemTextA(hDlg, nIDDlgItem, lpString, cchMax) = DLL("USER32.dll", "dword GetDlgItemTextA(void*, int, char*, int)")
# 呼び出し: GetDlgItemTextA(hDlg, nIDDlgItem, lpString, cchMax)
# hDlg : HWND -> "void*"
# nIDDlgItem : INT -> "int"
# lpString : LPSTR out -> "char*"
# cchMax : INT -> "int"
# 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)。