made change of commit b997641ba4 template-based: no runtime cost

thread_pool.hpp

@@ -52,8 +52,8 @@ class thread_pool
     /* the main loop of the threads */
     void loop();
 
-    template <typename F, typename... Args>
-    auto _add_task_internal(bool front, F&& f, Args&&... args)
+    template <bool front, typename F, typename... Args>
+    auto _add_task_internal(F&& f, Args&&... args)
     -> std::future<decltype(f(std::forward<Args>(args)...))>;
 
 public:
@@ -91,8 +91,8 @@ public:
     inline size_t get_queue_size() const { return queue.size(); }
 };
 
-template <typename F, typename... Args>
-auto thread_pool::_add_task_internal(bool front, F&& f, Args&&... args)
+template <bool front, typename F, typename... Args>
+auto thread_pool::_add_task_internal(F&& f, Args&&... args)
 -> std::future<decltype(f(std::forward<Args>(args)...))>
 {
     auto pckgd_tsk = std::make_shared<std::packaged_task<decltype(f(std::forward<Args>(args)...))()> >
@@ -130,14 +130,14 @@ template <typename F, typename... Args>
 auto thread_pool::add_task(F&& f, Args&&... args)
 -> std::future<decltype(f(std::forward<Args>(args)...))>
 {
-    return _add_task_internal(false, std::forward<F>(f), std::forward<Args>(args)...);
+    return _add_task_internal<false>(std::forward<F>(f), std::forward<Args>(args)...);
 }
 
 template <typename F, typename... Args>
 auto thread_pool::priority_task(F&& f, Args&&... args)
 -> std::future<decltype(f(std::forward<Args>(args)...))>
 {
-    return _add_task_internal(true, std::forward<F>(f), std::forward<Args>(args)...);
+    return _add_task_internal<true>(std::forward<F>(f), std::forward<Args>(args)...);
 }
 
 template <typename R>