GetRegionData

// GDI32.dll
#include <windows.h>

DWORD GetRegionData(
    HRGN hrgn,
    DWORD nCount,
    RGNDATA* lpRgnData   // optional
);

<DllImport("GDI32.dll", ExactSpelling:=True)>
Public Shared Function GetRegionData(
    hrgn As IntPtr,   ' HRGN
    nCount As UInteger,   ' DWORD
    lpRgnData As IntPtr   ' RGNDATA* optional, out
) As UInteger
End Function

' hrgn : HRGN
' nCount : DWORD
' lpRgnData : RGNDATA* optional, out
Declare PtrSafe Function GetRegionData Lib "gdi32" ( _
    ByVal hrgn As LongPtr, _
    ByVal nCount As Long, _
    ByVal lpRgnData 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

GetRegionData = ctypes.windll.gdi32.GetRegionData
GetRegionData.restype = wintypes.DWORD
GetRegionData.argtypes = [
    wintypes.HANDLE,  # hrgn : HRGN
    wintypes.DWORD,  # nCount : DWORD
    ctypes.c_void_p,  # lpRgnData : RGNDATA* optional, out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('GDI32.dll')
GetRegionData = Fiddle::Function.new(
  lib['GetRegionData'],
  [
    Fiddle::TYPE_VOIDP,  # hrgn : HRGN
    -Fiddle::TYPE_INT,  # nCount : DWORD
    Fiddle::TYPE_VOIDP,  # lpRgnData : RGNDATA* optional, out
  ],
  -Fiddle::TYPE_INT)

#[link(name = "gdi32")]
extern "system" {
    fn GetRegionData(
        hrgn: *mut core::ffi::c_void,  // HRGN
        nCount: u32,  // DWORD
        lpRgnData: *mut RGNDATA  // RGNDATA* optional, out
    ) -> u32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("GDI32.dll")]
public static extern uint GetRegionData(IntPtr hrgn, uint nCount, IntPtr lpRgnData);
"@
$api = Add-Type -MemberDefinition $sig -Name 'GDI32_GetRegionData' -Namespace Win32 -PassThru
# $api::GetRegionData(hrgn, nCount, lpRgnData)

#uselib "GDI32.dll"
#func global GetRegionData "GetRegionData" sptr, sptr, sptr
; GetRegionData hrgn, nCount, varptr(lpRgnData)   ; 戻り値は stat
; hrgn : HRGN -> "sptr"
; nCount : DWORD -> "sptr"
; lpRgnData : RGNDATA* optional, out -> "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 "GDI32.dll"
#cfunc global GetRegionData "GetRegionData" sptr, int, var
; res = GetRegionData(hrgn, nCount, lpRgnData)
; hrgn : HRGN -> "sptr"
; nCount : DWORD -> "int"
; lpRgnData : RGNDATA* optional, 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。

; DWORD GetRegionData(HRGN hrgn, DWORD nCount, RGNDATA* lpRgnData)
#uselib "GDI32.dll"
#cfunc global GetRegionData "GetRegionData" intptr, int, var
; res = GetRegionData(hrgn, nCount, lpRgnData)
; hrgn : HRGN -> "intptr"
; nCount : DWORD -> "int"
; lpRgnData : RGNDATA* optional, 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 (
	gdi32 = windows.NewLazySystemDLL("GDI32.dll")
	procGetRegionData = gdi32.NewProc("GetRegionData")
)

// hrgn (HRGN), nCount (DWORD), lpRgnData (RGNDATA* optional, out)
r1, _, err := procGetRegionData.Call(
	uintptr(hrgn),
	uintptr(nCount),
	uintptr(lpRgnData),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // DWORD

function GetRegionData(
  hrgn: THandle;   // HRGN
  nCount: DWORD;   // DWORD
  lpRgnData: Pointer   // RGNDATA* optional, out
): DWORD; stdcall;
  external 'GDI32.dll' name 'GetRegionData';

result := DllCall("GDI32\GetRegionData"
    , "Ptr", hrgn   ; HRGN
    , "UInt", nCount   ; DWORD
    , "Ptr", lpRgnData   ; RGNDATA* optional, out
    , "UInt")   ; return: DWORD

●GetRegionData(hrgn, nCount, lpRgnData) = DLL("GDI32.dll", "dword GetRegionData(void*, dword, void*)")
# 呼び出し: GetRegionData(hrgn, nCount, lpRgnData)
# hrgn : HRGN -> "void*"
# nCount : DWORD -> "dword"
# lpRgnData : RGNDATA* optional, 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)。