GetMailslotInfo

// KERNEL32.dll
#include <windows.h>

BOOL GetMailslotInfo(
    HANDLE hMailslot,
    DWORD* lpMaxMessageSize,   // optional
    DWORD* lpNextSize,   // optional
    DWORD* lpMessageCount,   // optional
    DWORD* lpReadTimeout   // optional
);

<DllImport("KERNEL32.dll", SetLastError:=True, ExactSpelling:=True)>
Public Shared Function GetMailslotInfo(
    hMailslot As IntPtr,   ' HANDLE
    lpMaxMessageSize As IntPtr,   ' DWORD* optional, out
    lpNextSize As IntPtr,   ' DWORD* optional, out
    lpMessageCount As IntPtr,   ' DWORD* optional, out
    lpReadTimeout As IntPtr   ' DWORD* optional, out
) As Boolean
End Function

' hMailslot : HANDLE
' lpMaxMessageSize : DWORD* optional, out
' lpNextSize : DWORD* optional, out
' lpMessageCount : DWORD* optional, out
' lpReadTimeout : DWORD* optional, out
Declare PtrSafe Function GetMailslotInfo Lib "kernel32" ( _
    ByVal hMailslot As LongPtr, _
    ByVal lpMaxMessageSize As LongPtr, _
    ByVal lpNextSize As LongPtr, _
    ByVal lpMessageCount As LongPtr, _
    ByVal lpReadTimeout 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

GetMailslotInfo = ctypes.windll.kernel32.GetMailslotInfo
GetMailslotInfo.restype = wintypes.BOOL
GetMailslotInfo.argtypes = [
    wintypes.HANDLE,  # hMailslot : HANDLE
    ctypes.POINTER(wintypes.DWORD),  # lpMaxMessageSize : DWORD* optional, out
    ctypes.POINTER(wintypes.DWORD),  # lpNextSize : DWORD* optional, out
    ctypes.POINTER(wintypes.DWORD),  # lpMessageCount : DWORD* optional, out
    ctypes.POINTER(wintypes.DWORD),  # lpReadTimeout : DWORD* optional, out
]
# GetLastError: use ctypes.GetLastError() (or ctypes.WinDLL(use_last_error=True))

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('KERNEL32.dll')
GetMailslotInfo = Fiddle::Function.new(
  lib['GetMailslotInfo'],
  [
    Fiddle::TYPE_VOIDP,  # hMailslot : HANDLE
    Fiddle::TYPE_VOIDP,  # lpMaxMessageSize : DWORD* optional, out
    Fiddle::TYPE_VOIDP,  # lpNextSize : DWORD* optional, out
    Fiddle::TYPE_VOIDP,  # lpMessageCount : DWORD* optional, out
    Fiddle::TYPE_VOIDP,  # lpReadTimeout : DWORD* optional, out
  ],
  Fiddle::TYPE_INT)

#[link(name = "kernel32")]
extern "system" {
    fn GetMailslotInfo(
        hMailslot: *mut core::ffi::c_void,  // HANDLE
        lpMaxMessageSize: *mut u32,  // DWORD* optional, out
        lpNextSize: *mut u32,  // DWORD* optional, out
        lpMessageCount: *mut u32,  // DWORD* optional, out
        lpReadTimeout: *mut u32  // DWORD* optional, out
    ) -> i32;
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("KERNEL32.dll", SetLastError = true)]
public static extern bool GetMailslotInfo(IntPtr hMailslot, IntPtr lpMaxMessageSize, IntPtr lpNextSize, IntPtr lpMessageCount, IntPtr lpReadTimeout);
"@
$api = Add-Type -MemberDefinition $sig -Name 'KERNEL32_GetMailslotInfo' -Namespace Win32 -PassThru
# $api::GetMailslotInfo(hMailslot, lpMaxMessageSize, lpNextSize, lpMessageCount, lpReadTimeout)

#uselib "KERNEL32.dll"
#func global GetMailslotInfo "GetMailslotInfo" sptr, sptr, sptr, sptr, sptr
; GetMailslotInfo hMailslot, varptr(lpMaxMessageSize), varptr(lpNextSize), varptr(lpMessageCount), varptr(lpReadTimeout)   ; 戻り値は stat
; hMailslot : HANDLE -> "sptr"
; lpMaxMessageSize : DWORD* optional, out -> "sptr"
; lpNextSize : DWORD* optional, out -> "sptr"
; lpMessageCount : DWORD* optional, out -> "sptr"
; lpReadTimeout : DWORD* 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 "KERNEL32.dll"
#cfunc global GetMailslotInfo "GetMailslotInfo" sptr, var, var, var, var
; res = GetMailslotInfo(hMailslot, lpMaxMessageSize, lpNextSize, lpMessageCount, lpReadTimeout)
; hMailslot : HANDLE -> "sptr"
; lpMaxMessageSize : DWORD* optional, out -> "var"
; lpNextSize : DWORD* optional, out -> "var"
; lpMessageCount : DWORD* optional, out -> "var"
; lpReadTimeout : DWORD* 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。

; BOOL GetMailslotInfo(HANDLE hMailslot, DWORD* lpMaxMessageSize, DWORD* lpNextSize, DWORD* lpMessageCount, DWORD* lpReadTimeout)
#uselib "KERNEL32.dll"
#cfunc global GetMailslotInfo "GetMailslotInfo" intptr, var, var, var, var
; res = GetMailslotInfo(hMailslot, lpMaxMessageSize, lpNextSize, lpMessageCount, lpReadTimeout)
; hMailslot : HANDLE -> "intptr"
; lpMaxMessageSize : DWORD* optional, out -> "var"
; lpNextSize : DWORD* optional, out -> "var"
; lpMessageCount : DWORD* optional, out -> "var"
; lpReadTimeout : DWORD* 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 (
	kernel32 = windows.NewLazySystemDLL("KERNEL32.dll")
	procGetMailslotInfo = kernel32.NewProc("GetMailslotInfo")
)

// hMailslot (HANDLE), lpMaxMessageSize (DWORD* optional, out), lpNextSize (DWORD* optional, out), lpMessageCount (DWORD* optional, out), lpReadTimeout (DWORD* optional, out)
r1, _, err := procGetMailslotInfo.Call(
	uintptr(hMailslot),
	uintptr(lpMaxMessageSize),
	uintptr(lpNextSize),
	uintptr(lpMessageCount),
	uintptr(lpReadTimeout),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // BOOL

function GetMailslotInfo(
  hMailslot: THandle;   // HANDLE
  lpMaxMessageSize: Pointer;   // DWORD* optional, out
  lpNextSize: Pointer;   // DWORD* optional, out
  lpMessageCount: Pointer;   // DWORD* optional, out
  lpReadTimeout: Pointer   // DWORD* optional, out
): BOOL; stdcall;
  external 'KERNEL32.dll' name 'GetMailslotInfo';

result := DllCall("KERNEL32\GetMailslotInfo"
    , "Ptr", hMailslot   ; HANDLE
    , "Ptr", lpMaxMessageSize   ; DWORD* optional, out
    , "Ptr", lpNextSize   ; DWORD* optional, out
    , "Ptr", lpMessageCount   ; DWORD* optional, out
    , "Ptr", lpReadTimeout   ; DWORD* optional, out
    , "Int")   ; return: BOOL

●GetMailslotInfo(hMailslot, lpMaxMessageSize, lpNextSize, lpMessageCount, lpReadTimeout) = DLL("KERNEL32.dll", "bool GetMailslotInfo(void*, void*, void*, void*, void*)")
# 呼び出し: GetMailslotInfo(hMailslot, lpMaxMessageSize, lpNextSize, lpMessageCount, lpReadTimeout)
# hMailslot : HANDLE -> "void*"
# lpMaxMessageSize : DWORD* optional, out -> "void*"
# lpNextSize : DWORD* optional, out -> "void*"
# lpMessageCount : DWORD* optional, out -> "void*"
# lpReadTimeout : DWORD* 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)。