lua_register C ++的问题

Question

I am having an issue with using lua_register function to put my C/C++ functions into Lua. Here is the code I have for my project:

    LuaCore::LuaCore()
    {
         L = luaL_newstate();
         luaopen_io(L);
         luaopen_base(L);
         luaopen_table(L);
         luaopen_string(L);
         luaopen_math(L);
         luaL_openlibs(L); 
     }


     LuaCore::~LuaCore()
     {
         if (L != NULL)
         {
             lua_close(L);
         }
     }

     void LuaCore::reportErrors(lua_State *l, int status)
     {
          if (status != 0)
          {
               agk::Message(lua_tostring(L, -1));
               lua_pop(L, 1);
          }
     }

     bool LuaCore::executeFile(const char* f)
     {
           int s = luaL_loadfile(L, f);
           if (s == 0)
           {
                s = lua_pcall(L, 0, LUA_MULTRET, 0);
           }
           reportErrors(L, s);
           return true;
      }

      void LuaCore::loadFunctions()
      {
            lua_register(L, "Print", Print);
      }


      void  LuaCore::Print(lua_State *L)
      {
            int argc = lua_gettop(L);
            for (int n = 1; n <= argc; ++n)
            {
                 if (n > 2)
                 {
                     std::cout << lua_tostring(L,n);
                 }
           }
      }

here is the header file:

    #pragma once

     extern "C"
     {
          #include "lua_lib\lua-5.3.1\src\lua.hpp"
     }

     #include <cstdlib>
     #include <cstring>
     #include <string>
     #include <iostream>
     using namespace std;


     class LuaCore
     {
      public:
          LuaCore();
          ~LuaCore();

          bool executeFile(const char* f);
          void reportErrors(lua_State *l, int status);
          void loadFunctions();

          void Print(lua_State *l);

          lua_State *L;

     };

also here is the error:

    Error   1   error C2664: 'void lua_pushcclosure(lua_State 
    *,lua_CFunction,int)' : cannot convert argument 2 from 'void (__thiscall
    LuaCore::* )(lua_State *)' to 'lua_CFunction'   C:\Program Files 
    (x86)\The Game Creators\AGK2\Tier 2\apps\EasyCoreGamer_\LuaCore.cpp 46
    1   Template

also with the intelliSense:

        2   IntelliSense: argument of type "void (LuaCore::*)(lua_State *L)"
        is incompatible with parameter of type "lua_CFunction"  c:\Program 
        Files (x86)\The Game Creators\AGK2\Tier 
        2\apps\EasyCoreGamer_\LuaCore.cpp   46  2   Template

So all together I was able to get Lua to run just fine with C++ and I was able to call lua scripts in C++. The only problem is trying to call C functions inside the lua scripts. I am really stuck and thank you in advance!

Answer 1

Your Print Function has the wrong type.

you should get the same error from

 lua_CFunction f{ Print };

f has the correct type here. Rewrite your print to fit that type.