RegisterDragDrop

// OLE32.dll
#include <windows.h>

HRESULT RegisterDragDrop(
    HWND hwnd,
    IDropTarget* pDropTarget
);

<DllImport("OLE32.dll", ExactSpelling:=True)>
Public Shared Function RegisterDragDrop(
    hwnd As IntPtr,   ' HWND
    pDropTarget As IntPtr   ' IDropTarget*
) As Integer
End Function

' hwnd : HWND
' pDropTarget : IDropTarget*
Declare PtrSafe Function RegisterDragDrop Lib "ole32" ( _
    ByVal hwnd As LongPtr, _
    ByVal pDropTarget 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

RegisterDragDrop = ctypes.windll.ole32.RegisterDragDrop
RegisterDragDrop.restype = ctypes.c_int
RegisterDragDrop.argtypes = [
    wintypes.HANDLE,  # hwnd : HWND
    ctypes.c_void_p,  # pDropTarget : IDropTarget*
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('OLE32.dll')
RegisterDragDrop = Fiddle::Function.new(
  lib['RegisterDragDrop'],
  [
    Fiddle::TYPE_VOIDP,  # hwnd : HWND
    Fiddle::TYPE_VOIDP,  # pDropTarget : IDropTarget*
  ],
  Fiddle::TYPE_INT)

#[link(name = "ole32")]
extern "system" {
    fn RegisterDragDrop(
        hwnd: *mut core::ffi::c_void,  // HWND
        pDropTarget: *mut core::ffi::c_void  // IDropTarget*
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("OLE32.dll")]
public static extern int RegisterDragDrop(IntPtr hwnd, IntPtr pDropTarget);
"@
$api = Add-Type -MemberDefinition $sig -Name 'OLE32_RegisterDragDrop' -Namespace Win32 -PassThru
# $api::RegisterDragDrop(hwnd, pDropTarget)

#uselib "OLE32.dll"
#func global RegisterDragDrop "RegisterDragDrop" sptr, sptr
; RegisterDragDrop hwnd, pDropTarget   ; 戻り値は stat
; hwnd : HWND -> "sptr"
; pDropTarget : IDropTarget* -> "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 "OLE32.dll"
#cfunc global RegisterDragDrop "RegisterDragDrop" sptr, sptr
; res = RegisterDragDrop(hwnd, pDropTarget)
; hwnd : HWND -> "sptr"
; pDropTarget : IDropTarget* -> "sptr"

; HRESULT RegisterDragDrop(HWND hwnd, IDropTarget* pDropTarget)
#uselib "OLE32.dll"
#cfunc global RegisterDragDrop "RegisterDragDrop" intptr, intptr
; res = RegisterDragDrop(hwnd, pDropTarget)
; hwnd : HWND -> "intptr"
; pDropTarget : IDropTarget* -> "intptr"

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

var (
	ole32 = windows.NewLazySystemDLL("OLE32.dll")
	procRegisterDragDrop = ole32.NewProc("RegisterDragDrop")
)

// hwnd (HWND), pDropTarget (IDropTarget*)
r1, _, err := procRegisterDragDrop.Call(
	uintptr(hwnd),
	uintptr(pDropTarget),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // HRESULT

function RegisterDragDrop(
  hwnd: THandle;   // HWND
  pDropTarget: Pointer   // IDropTarget*
): Integer; stdcall;
  external 'OLE32.dll' name 'RegisterDragDrop';

result := DllCall("OLE32\RegisterDragDrop"
    , "Ptr", hwnd   ; HWND
    , "Ptr", pDropTarget   ; IDropTarget*
    , "Int")   ; return: HRESULT

●RegisterDragDrop(hwnd, pDropTarget) = DLL("OLE32.dll", "int RegisterDragDrop(void*, void*)")
# 呼び出し: RegisterDragDrop(hwnd, pDropTarget)
# hwnd : HWND -> "void*"
# pDropTarget : IDropTarget* -> "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)。