template<typename T> struct State
{
    std::map<std::string, T> statedata;
    static std::mutex mux_state;
    ...
    void update(std::string k, T t)
    {
        while (!mux_state.try_lock()) timeoutdelay(TOD_UPDATE);
        ..do update..
        mux_state.unlock();
    }
    ...
    T read(std::string k)
    {
        while (!mux_state.try_lock()) timeoutdelay(TOD_READ);
        T t=statedata[k];
        mux_state.unlock();
        return t;
    }
    ...
}
...
State<mytype> state;
...
..from thread_1() randomly
    state.update(..)
...
..from thread_2() randomly
    state.read(..)