Problem with marshalling native function

[flo8464]

Hey

I currently try to marshall a function with this prototype

const char* __thiscall GetName(DWORD thisPointer);

My attempt was

[UnmanagedFunctionPointer(CallingConvention.ThisCall)]
private delegate [MarshalAs(UnmanagedType.LPStr)] string GetNameDelegate(uint thisPointer);

but this obviously doesn't work. Any way to fix this?

Thanks.

[Apoc]

[UnmanagedFunctionPointer(CallingConvention.ThisCall)]
[return: MarshalAs(UnmanagedType.LPStr)]
public delegate string GetName(IntPtr instance);

[flo8464]

Thank you, works just fine

[flo8464]

For some strange reason, calling a specific function does just not work. I really can't figure out why. The prototype is 100% correct, the address also.

(I use your WhiteMagic in that snippet)

        #region Player__Interact
        /// <summary>
        /// Interacts with a object
        /// </summary>
        /// <param name="thisPointer">Pointer to the currently active player</param>
        /// <param name="targetPointer">Pointer to a valid object</param>
        /// <returns>Unknown error codes</returns>
        [UnmanagedFunctionPointer(CallingConvention.ThisCall)]
        public delegate int Player__InteractDelegate(uint thisPointer, uint targetPointer);

        public static readonly Player__InteractDelegate Player__Interact = Core.magic.RegisterDelegate<Player__InteractDelegate>((uint)StaticData.FunctionAddresses.PLAYER__INTERACT);
        #endregion

Every time I call it, an exception is thrown:

************** Exception Text **************
System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
at Synthetic.Internals.EngineFunctions.Player__InteractDelegate.Invoke(UInt32 thisPointer, UInt32 targetPointer)
at Synthetic.Objects.PlayerObject.Interact(GameObject target) in C:\Users\flo\Desktop\Synthetic\Synthetic\Objects\PlayerObject.cs:line 35
at Synthetic.Form1.button3_Click(Object sender, EventArgs e) in C:\Users\flo\Desktop\Synthetic\Synthetic\Form1.cs:line 110
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

I can't figure out why, calling it in my C++ app works perfectly.
Oh, and I don't really know much about C#, just trying to port some code.

I already attached a debugger, I never get to know where a problem occurs.

Thanks
Flo

[YetiHunter]

ok i have no idea if what i'm saying is right, but why the "thispointer" i think it should be something like this:

        [UnmanagedFunctionPointer(CallingConvention.ThisCall)]
        private delegate IntPtr InteractDelegate(IntPtr instance);
        private InteractDelegate _interact;
        public virtual void Interact()
        {
            if (_interact == null)
            {
                _interact = Main.m.RegisterDelegate<InteractDelegate>(GetVFunc(VFunc.Interact));
            }
            _interact(this);
        }

[flo8464]

Thanks, but already found the answer (I am stupid).

To come back to my previous problem, Apoc's solution tends to make problems. Here a version, which works without flaws, at least in my testings:

[UnmanagedFunctionPointer(CallingConvention.ThisCall)]
public delegate IntPtr Object__GetNameDelegate(uint thisPointer);

....

        public string Name
        {
            get
            {
                if (IsValid)
                {
                    return Marshal.PtrToStringAnsi(Internals.EngineFunctions.Object__GetName(ObjectPointer));
                }

                return "InvalidObject";
            }
        }