std::recursive_mutex g_myDataMutex;
std::string myString ;

void SetValueSync(std::string const in_newValue)
{
    for (int i = 0; i<10000; i++)
    {
        std::lock_guard<std::recursive_mutex> myLock(g_myDataMutex);
        myString = myString + in_newValue;
    }
}

int main()
{
    std::thread t1(SetValueSync, "ABC");
    std::thread t2(SetValueSync, "___");
    t2.join();
    t1.join();

    cout<<myString;
    return 0
}