--- name: "ACE_Timer_List_T" section: "3" platform: "linux" package: "libace-doc" version: "5.0.7-4" release: "Debian 2.2 (Potato)" platforms: ["linux"] url: "https://new.carta.tech/ACE_Timer_List_T" --- # ACE\_Timer\_List\_T(3) Provides a simple implementation of timers. ## NAME ACE\_Timer\_List\_T - Provides a simple implementation of timers. ## SYNOPSIS ``` #include template class ACE_Timer_List_T : public ACE_Timer_Queue_T { public: typedef ACE_Timer_List_Iterator_T LIST_ITERATOR; friend class ACE_Timer_List_Iterator_T; typedef ACE_Timer_Queue_T INHERITED; ACE_Timer_List_T ( FUNCTOR *upcall_functor = 0, ACE_Free_List > *freelist = 0 ); virtual ~ACE_Timer_List_T (void); virtual int is_empty (void) const; virtual const ACE_Time_Value &earliest_time (void) const; virtual long schedule ( const TYPE &type, const void *act, const ACE_Time_Value &delay, const ACE_Time_Value &interval = ACE_Time_Value::zero ); virtual int reset_interval ( long timer_id, const ACE_Time_Value &interval ); virtual int cancel ( const TYPE &type, int dont_call_handle_close = 1 ); virtual int cancel ( long timer_id, const void **act = 0, int dont_call_handle_close = 1 ); virtual ACE_Timer_Queue_Iterator_T &iter ( void ); virtual ACE_Timer_Node_T *remove_first (void); virtual void dump (void) const; virtual void reschedule (ACE_Timer_Node_T *); virtual ACE_Timer_Node_T *get_first (void); protected: /* virtual ACE_Timer_Node_T *alloc_node (void); virtual void free_node (ACE_Timer_Node_T *); private: ACE_Timer_Node_T *head_; LIST_ITERATOR *iterator_; long timer_id_; inline ACE_UNIMPLEMENTED_FUNC ( ACE_Timer_List_T (const ACE_Timer_List_T &) ); }; ``` ## DESCRIPTION This implementation uses a linked list of absolute times. Therefore, in the average case, scheduling and canceling timers is O(N) (where N is the total number of timers) and expiring timers is O(K) (where K is the total number of timers that are the current time of day). More clever implementations could use a delta-list, a heap, or timing wheels, etc. For instance, ACE\_Timer\_Heap is a subclass of ACE\_Timer\_List that implements a heap-based callout queue. For most applications, the ACE\_Timer\_Heap will perform substantially faster than the ACE\_Timer\_List. ## Initialization and termination methods. ``` ACE_Timer_List_T ( FUNCTOR *upcall_functor = 0, ACE_Free_List > *freelist = 0 ); ``` Default constructor. upcall\_functor is the instance of the FUNCTOR to be used by the list. If upcall\_functor is 0, a default FUNCTOR will be created. freelist the freelist of timer nodes. If 0, then a default freelist will be created. ``` virtual ~ACE_Timer_List_T (void); ``` Destructor ``` virtual int is_empty (void) const; ``` True if queue is empty, else false. ``` virtual const ACE_Time_Value &earliest_time (void) const; ``` Returns the time of the earlier node in the ACE\_Timer\_List. ``` virtual long schedule ( const TYPE &type, const void *act, const ACE_Time_Value &delay, const ACE_Time_Value &interval = ACE_Time_Value::zero ); ``` Schedule type that will expire after delay amount of time, which is specified in absolute time. If it expires then act is passed in as the value to the functor. If interval is != to ACE\_Time\_Value::zero then it is used to reschedule the type automatically, using relative time to the current gettimeofday. This method returns a timer\_id that uniquely identifies the the type entry in an internal list. This timer\_id can be used to cancel the timer before it expires. The cancellation ensures that timer\_ids are unique up to values of greater than 2 billion timers. As long as timers don't stay around longer than this there should be no problems with accidentally deleting the wrong timer. Returns -1 on failure (which is guaranteed never to be a valid timer\_id). ``` virtual int reset_interval ( long timer_id, const ACE_Time_Value &interval ); ``` Resets the interval of the timer represented by timer\_id to interval, which is specified in relative time to the current gettimeofday. If interval is equal to ACE\_Time\_Value::zero, the timer will become a non-rescheduling timer. Returns 0 if successful, -1 if not. ``` virtual int cancel (const TYPE &type, int dont_call_handle_close = 1); ``` Cancel all timer associated with type. If dont\_call is 0 then the functor will be invoked. Returns number of timers cancelled. ``` virtual int cancel ( long timer_id, const void **act = 0, int dont_call_handle_close = 1 ); ``` Cancel the single timer that matches the timer\_id value (which was returned from the schedule method). If act is non-NULL then it will be set to point to the \`\`magic cookie'' argument passed in when the timer was registered. This makes it possible to free up the memory and avoid memory leaks. If dont\_call is 0 then the functor will be invoked. Returns 1 if cancellation succeeded and 0 if the timer\_id wasn't found. ``` virtual ACE_Timer_Queue_Iterator_T &iter ( void ); ``` Returns a pointer to this ACE\_Timer\_Queue's iterator. ``` virtual ACE_Timer_Node_T *remove_first (void); ``` Removes the earliest node from the queue and returns it ``` virtual void dump (void) const; ``` Dump the state of an object. ``` virtual void reschedule (ACE_Timer_Node_T *); ``` Reschedule an "interval" ACE\_Timer\_Node. This should be private but for now it needs to be public for ACE\_Timer\_Hash\_T ``` virtual ACE_Timer_Node_T *get_first (void); ``` Reads the earliest node from the queue and returns it. ## Don't allow these operations for now. ``` inline ACE_UNIMPLEMENTED_FUNC ( ACE_Timer_List_T (const ACE_Timer_List_T &) ); ``` ## AUTHOR Doug Schmidt ## LIBRARY ace