lua_tolstring

[danwins]

Having some issues trying to get this to work.

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate string lua_tolstringDelegate(IntPtr pLuaState, int Index, int Length);

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        private delegate double lua_tonumberDelegate(IntPtr pLuaState, int Index);

        private static lua_tolstringDelegate lua_tolstringHandler;
        private static lua_tonumberDelegate lua_tonumberHandler;

omitted some stuff for simplicity, but all the delegates are registered properly.

when calling the script from in-game it reaches my callback:

ex: /script TriggersCallback("test");

        private static int CallBackHandler(pIntPtr LuaState)
        {
            int num = lua_gettopHandler(pLuaState);
            if (num >= 1) // atleast 1 arg passed
            {
                string tmp = lua_tolstringHandler(pLuaState, 1, 0);
                //tmp should now contain "test" but instead crashes wow.
            }
            return 0;
        }

it crashes when it attempts to call lua_tolstring.
the same method, but with tonumber works fine:

ex: /script TriggersCallback(1234);

        private static int CallBackHandler(IntPtr pLuaState)
        {
            int num = lua_gettopHandler(pLuaState);
            if (num >= 1) // atleast 1 arg passed
            {
                double tmp = lua_tonumberHandler(pLuaState, 1);
                //tmp now contains "1234" (it actually does).
            }
            return 0;
        }

This crash also produces a blank crash log from WoW.

my offsets:

lua_tolstring = 0xD567F
lua_tonumber = 0xD55C6

Anyone know what my issue is?

[Bananenbrot]

Your tolstring delegate is wrong. You need to pass length by reference. So in C# you'd either declare it out or pass an IntPtr. I'd go for the former:

private delegate string lua_tolstringDelegate(IntPtr pLuaState, int Index, out int Length);

If you are not interested in the length, you can also declare the IntPtr variant and pass IntPtr.Zero.

[danwins]

the point is just to pass a null pointer, if i do it as IntPtr.Zero or uint 0x0 it still crashes.

[SKU]

I have no idea of managed<->unmanaged operations, but can the CLR just deal with strings like that? Your address seems correct and declaring the last argument as an integer should work as well if you pass 0, assuming it's pushed onto the stack as 'expected'. Have you stepped through the code?

c# - PInvoke for C function that returns char * - Stack Overflow

[Bananenbrot]

I have no idea of managed<->unmanaged operations, but can the CLR just deal with strings like that? Your address seems correct and declaring the last argument as an integer should work as well if you pass 0, assuming it's pushed onto the stack as 'expected'. Have you stepped through the code?

c# - PInvoke for C function that returns char * - Stack Overflow

Right, you have to Marshal.PtrToStringAuto() the IntPtr return value.

[TOM_RUS]

Since pointer returned by lua_tolstring points on UTF-8 encoded string, it's better read it manually. Marshal.PtrToStringXXX doesn't work with UTF-8.

[Bananenbrot]

Since pointer returned by lua_tolstring points on UTF-8 encoded string, it's better read it manually. Marshal.PtrToStringXXX doesn't work with UTF-8.

That's helpful... Thanks