- std::condition_variable non_empty_c_; // q went non-empty
- std::condition_variable has_space_c_; // q is not longer overfull
- unsigned int max_; //maximum capacity of the queue, block enq threads if exceeds this limit
+ cond non_empty_c_; // q went non-empty
+ cond has_space_c_; // q is not longer overfull
+ size_t max_; // maximum capacity of the queue, block enq threads if exceeds this limit