DLL部分:

#ifdef __cplusplus
extern "C" {
#endif

#include <lua/lua.h>
#include <lua/lualib.h>
#include <lua/lauxlib.h>

#ifdef __cplusplus
}
#endif

#pragma comment( lib, "lua51.lib" )

#define TOSTRING(x) #x
#define EXPORT_SYMBOL_TO_LUA(str) { TOSTRING(str), str }

static int MsgBox(lua_State* L)
{
    const char* pStr = lua_tostring(L, -1);
    MessageBoxA( NULL, pStr, "message", MB_OK );
    return 0;
}

static const luaL_reg MyDLLFunctions [] =
{
    EXPORT_SYMBOL_TO_LUA(MsgBox),
    {NULL, NULL}
};
//需要注意的地方,此函数命名与库名一致
extern "C" int __declspec(dllexport) luaopen_DllForLua(lua_State* L)
{
    luaL_openlib(L, "MyExt", MyDLLFunctions, 0);
    return 1;
}

Lua调用部分:

n = 1;
if n == 1 then					--加载方法一
	local lib = package.loadlib("./Debug/DllForLua.dll", "luaopen_DllForLua");
	if lib then
		lib()                       --需要注意的地方
	else
		print("Load Dll Error!");
	end

elseif n == 2 then				--加载方法二
	package.cpath = string.format("%s;./Debug/?.dll", package.cpath);
	require("DllForLua")
end

MyExt.MsgBox("Everything is OK!");