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POshould I make member functions that work with an adjustable clock static?
 

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  1. POshould I make member functions that work with an adjustable clock static?
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    <p>I have the following two headers.</p> <pre><code>#ifndef DRD_EVENT_HPP #define DRD_EVENT_HPP #include &lt;functional&gt; namespace drd { template &lt;typename Clock&gt; class event { public: using clock = Clock; using time_point = typename clock::time_point; template &lt;class F, class... Args&gt; event(time_point et, F&amp;&amp; f, Args&amp;&amp;... args) : Task(std::bind&lt;void&gt;(std::forward&lt;F&gt;(f), std::forward&lt;Args&gt;(args)...)), Time(et) {} void perform() ///Can throw std::bad_function_call { Task(); Task = nullptr; } ///Returns the event time. time_point time() const noexcept { return Time; } ///Checks if the event has not been performed yet. bool pending() const noexcept { return static_cast&lt;bool&gt;(Task); } private: std::function&lt; void()&gt; Task; time_point Time; }; struct later_event { template &lt;class Clock&gt; bool operator()(const event&lt;Clock&gt;&amp; lhs, const event&lt;Clock&gt;&amp; rhs) const noexcept { return lhs.time() &gt; rhs.time(); } }; } #endif // DRD_EVENT_HPP #ifndef DRD_DISCRETE_SIMULATION_HPP #define DRD_DISCRETE_SIMULATION_HPP #include &lt;exception&gt; #include &lt;chrono&gt; #include &lt;queue&gt; #include "event.hpp" namespace drd { namespace des ///Discrete event simulation { template &lt;class Rep, class Period = std::ratio&lt;1&gt;&gt; class simulation_engine { public: class clock; using time_point = typename clock::time_point; using duration = typename clock::duration; using event_type = event&lt;clock&gt;; public: ///Constructs an event "in-place" and inserts it in the events list template &lt;typename... EventArgs&gt; void schedule(EventArgs&amp;&amp;... event_args_) { EventsList.emplace(std::forward&lt;EventArgs&gt;(event_args_)...); } bool has_pending_events() const noexcept { return not EventsList.empty(); } ///Advances the clock until the next event time and then the event ///is performed, if the events list was empty the behavior is undefined. void next_event() { auto Event = EventsList.top(); EventsList.pop(); clock::advance_until(Event.time()); Event.perform(); } ///Calls next_event() while the events list is not empty. void simulate() { while (has_pending_events()) next_event();} ///Performs all of events whose time is scheduled before or just at the ///moment t, then advances the clock until t. void simulate_until(time_point t) { while(has_pending_events() and EventsList.top().time() &lt;= t) next_event(); clock::advance_until(t); } void simulate_for(duration d) { simulate_until(clock::now() + d); } private: std::priority_queue&lt;event_type, std::vector&lt;event_type&gt;, later_event&gt; EventsList; }; ///clock type that is thread-independent and adjustable by ///simulation_engine template &lt;class Rep, class Period&gt; class simulation_engine&lt;Rep,Period&gt;::clock { public: using rep = Rep; using period = Period; using duration = std::chrono::duration&lt;rep,period&gt;; using time_point = std::chrono::time_point&lt;clock&gt;; public: static constexpr bool is_steady = false; public: static time_point now() noexcept { return CurrentTime;} private: static void reset() noexcept { CurrentTime = time_point(); } static void adjust(time_point t) noexcept { CurrentTime = t; } static void advance_until(time_point t) { if(t &lt; CurrentTime) throw std::logic_error("advance_until cannot set the clock back."); CurrentTime = t; } friend simulation_engine&lt;Rep,Period&gt;; private: static thread_local time_point CurrentTime; }; template &lt;class Rep, class Period&gt; thread_local typename simulation_engine&lt;Rep,Period&gt;::clock::time_point simulation_engine&lt;Rep,Period&gt;::clock::CurrentTime; } } #endif //DRD_DISCRETE_SIMULATION_HPP </code></pre> <p>I was wondering if I should make member functions of simulation_engine static, because objects own independent events list and share the same clock, and might happen a synchronization problem. </p> <p>What should I do?</p> <p>Sorry for my english and the extensive code. I hope your answer, thank you in advance.</p>
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