Lua dynamic library how to call DLL?-CodePudding

I use VS19 generates a dynamic library, the dynamic library source code is as follows:

 # include & lt; iostream> 
Extern "C" 
{
# include & lt; Lua. H> 
# include & lt; Lualib. H> 
# include & lt; Lauxlib. H> 
} 

Static int retStr (lua_State * L) 
{
Lua_pushstring (L, "is this DLL return a string"); 
return 1; 
} 

The static const luaL_Reg util []={
{" getStr ", retStr}, 
{NULL NULL} 
}; 

Extern "C" __declspec (dllexport) 
Int luaopen_luacalldll (lua_State * L) {
LuaL_newlib (L, util); 
return 1; 
}

After generating the dynamic library, I in the same directory as the it made a lua files:

The lua file code is as follows:

 local obj=the require (" luacalldll ") 
Print (obj. GetStr ())

But I can't run the lua files, an error figure below:

Where is my wrong, why my DLL are generated, or can not call it?