[Mono-list] IntPtr safety (was: need some help with PInvoke..)

[Hervé Poussineau]

>I guess this is my confusion. HWND* is _safer_ than IntPtr, because it
>is a pointer to a specific type. It's the operations on HWND* that are
>unsafe. It seems like it would be better if VB (and other languages
>without unsafe) had the ability to express HWND*, and simply not
>operate on it.
>
>Certainly this:
>    .field  public   valuetype HDF* p
>
>Is better than this:
>    .field  public   native int p

Why don't you write a struct that contains only a HWND* ? So, you can simply
express your HWND* in safe code. Moreover, you can mark certain methods as
"internal" for more security

public struct HWndPtr : ISerializable
{
        private IntPtr _Pointer;

        public static readonly HWndPtr Zero = new
HWndPtr(IntPtr.Zero.ToInt64());

        public static int Size { get { return IntPtr.Size; } }

        public HWndPtr(int hWnd) { _Pointer = new IntPtr(hWnd); }
        public HWndPtr(long hWnd) { _Pointer = new IntPtr(hWnd); }
        unsafe public HWndPtr(void* hWnd) { _Pointer = new IntPtr(hWnd); }

        public int ToInt32() { return _Pointer.ToInt32(); }
        public long ToInt64() { return _Pointer.ToInt64(); }
        public IntPtr ToIntPtr() { return _Pointer; }
        [CLSCompliant(false)]
        unsafe public void* ToPointer() { return _Pointer.ToPointer(); }

        public static bool operator == (HWndPtr value1, HWndPtr value2)
        { return value1._Pointer == value2._Pointer; }
        public static bool operator != (HWndPtr value1, HWndPtr value2)
        { return value1._Pointer != value2._Pointer; }
        public static explicit operator HWndPtr(int value)
        { return new HWndPtr(value); }
        public static explicit operator HWndPtr(long value)
        { return new HWndPtr(value); }
        public static explicit operator int(HWndPtr value)
        { return (int)value._Pointer; }
        public static explicit operator long(HWndPtr value)
        { return (long)value._Pointer; }
        [CLSCompliant(false)]
        unsafe public static explicit operator void*(HWndPtr value)
        { return (void*)value._Pointer; }
        [CLSCompliant(false)]
        unsafe public static explicit operator HWndPtr(void* value)
        { return new HWndPtr(value); }

        public void GetObjectData(SerializationInfo info, StreamingContext
context)
        { throw new NotImplementedException(); }
}

Hervé

PS: I hope you will understand my English...