C++ Calling variable(c++) from LUA

[lexus21]

I use OTCv8 for my small project.
I have a module for otclientv8 written in C++. The module generates numbers every second into a variable.
I would like to have access to this variable from lua to use this variable in a lua script.
I'm wondering and slowly eating my mustache on this code(my experience in c++ is small).
How to read a variable (c++) in lua code?


in the file
luavaluecasts_client.cpp
I added:

int push_luavalue(const COM&Testdata)
{
     g_lua.createTable(0, 1);


     g_lua.pushInteger(10); // <--hardcoded value 10 - only for learnig only for learning purpose (imitates a variable)
     g_lua.setField("testDatavalue");


     return 1;
}

while in otclient, in modules, I created a sample module which should display the value 10. After opening the window.

--window
function show()
   tWindow:show()
   if Testdata then
     print("this is testdata: ", Testdata.testDatavalue)
   end
   print("Hello")
   tButton:setOn(true)
end

What am I doing wrong that I don't have access to the variable from lua?