## NAME

ACE_Reactor - The resposiblility of this class is to forward all methods to its delegation/implementation class, e.g., `ACE_Select_Reactor` or `ACE_WFMO_Reactor`.

## SYNOPSIS

    #include <ace/Reactor.h>

    class ACE_Reactor
    {
      public:
        enum{ GET_MASK = 1, SET_MASK = 2, ADD_MASK = 3, CLR_MASK = 4 };
        typedef int (*REACTOR_EVENT_HOOK)(void*);
        static ACE_Reactor *instance (void);
        static ACE_Reactor *instance (
            ACE_Reactor *,
            int delete_reactor = 0
            );
        static void close_singleton (void);
        static int run_event_loop (void);
        static int run_alertable_event_loop (void);
        static int run_event_loop (ACE_Time_Value &tv);
        static int run_alertable_event_loop (ACE_Time_Value &tv);
        static int end_event_loop (void);
        static int event_loop_done (void);
        static void reset_event_loop (void);
        static int check_reconfiguration (void *);
        virtual int run_reactor_event_loop (REACTOR_EVENT_HOOK = 0);
        virtual int run_alertable_reactor_event_loop (
            REACTOR_EVENT_HOOK = 0
            );
        virtual int run_reactor_event_loop (
            ACE_Time_Value &tv,
            REACTOR_EVENT_HOOK = 0
            );
        virtual int run_alertable_reactor_event_loop (
            ACE_Time_Value &tv,
            REACTOR_EVENT_HOOK = 0
            );
        virtual int end_reactor_event_loop (void);
        virtual int reactor_event_loop_done (void);
        virtual void reset_reactor_event_loop (void);
        ACE_Reactor (
            ACE_Reactor_Impl *implementation = 0,
            int delete_implementation = 0
            );
        virtual ~ACE_Reactor (void);
        virtual int open (
            size_t max_number_of_handles,
            int restart = 0,
            ACE_Sig_Handler *signal_handler = 0,
            ACE_Timer_Queue *timer_queue = 0
            );
        virtual int set_sig_handler (ACE_Sig_Handler *signal_handler);
        virtual int set_timer_queue (ACE_Timer_Queue *timer_queue);
        virtual int close (void);
        virtual int work_pending (
            const ACE_Time_Value &max_wait_time = ACE_Time_Value::zero
            );
        virtual int handle_events (ACE_Time_Value *max_wait_time = 0);
        virtual int alertable_handle_events (
            ACE_Time_Value *max_wait_time = 0
            );
        virtual int handle_events (ACE_Time_Value &max_wait_time);
        virtual int alertable_handle_events (
            ACE_Time_Value &max_wait_time
            );
        virtual int register_handler (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            );
        virtual int register_handler (
            ACE_HANDLE io_handle,
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            );
        virtual int register_handler (
            ACE_Event_Handler *event_handler,
            ACE_HANDLE event_handle = ACE_INVALID_HANDLE
            );
        virtual int register_handler (
            ACE_HANDLE event_handle,
            ACE_HANDLE io_handle,
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            );
        virtual int register_handler (
            const ACE_Handle_Set &handles,
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            );
        virtual int register_handler (
            int signum,
            ACE_Event_Handler *new_sh,
            ACE_Sig_Action *new_disp = 0,
            ACE_Event_Handler **old_sh = 0,
            ACE_Sig_Action *old_disp = 0
            );
        virtual int register_handler (
            const ACE_Sig_Set &sigset,
            ACE_Event_Handler *new_sh,
            ACE_Sig_Action *new_disp = 0
            );
        virtual int remove_handler (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            );
        virtual int remove_handler (
            ACE_HANDLE handle,
            ACE_Reactor_Mask mask
            );
        virtual int remove_handler (
            const ACE_Handle_Set &handle_set,
            ACE_Reactor_Mask mask
            );
        virtual int remove_handler (
            int signum,
            ACE_Sig_Action *new_disp,
            ACE_Sig_Action *old_disp = 0,
            int sigkey = -1
            );
        virtual int remove_handler (const ACE_Sig_Set &sigset);
        virtual int suspend_handler (ACE_Event_Handler *event_handler);
        virtual int suspend_handler (ACE_HANDLE handle);
        virtual int suspend_handler (const ACE_Handle_Set &handles);
        virtual int suspend_handlers (void);
        virtual int resume_handler (ACE_Event_Handler *event_handler);
        virtual int resume_handler (ACE_HANDLE handle);
        virtual int resume_handler (const ACE_Handle_Set &handles);
        virtual int resume_handlers (void);
        virtual long schedule_timer (
            ACE_Event_Handler *event_handler,
            const void *arg,
            const ACE_Time_Value &delta,
            const ACE_Time_Value &interval = ACE_Time_Value::zero
            );
        virtual int cancel_timer (
            ACE_Event_Handler *event_handler,
            int dont_call_handle_close = 1
            );
        virtual int cancel_timer (
            long timer_id,
            const void **arg = 0,
            int dont_call_handle_close = 1
            );
        virtual int schedule_wakeup (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask masks_to_be_added
            );
        virtual int schedule_wakeup (
            ACE_HANDLE handle,
            ACE_Reactor_Mask masks_to_be_added
            );
        virtual int cancel_wakeup (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask masks_to_be_cleared
            );
        virtual int cancel_wakeup (
            ACE_HANDLE handle,
            ACE_Reactor_Mask masks_to_be_cleared
            );
        virtual int notify (
            ACE_Event_Handler *event_handler = 0,
            ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK,
            ACE_Time_Value *tv = 0
            );
        virtual void max_notify_iterations (int iterations);
        virtual int max_notify_iterations (void);
        virtual int handler (
            ACE_HANDLE handle,
            ACE_Reactor_Mask mask,
            ACE_Event_Handler **event_handler = 0
            );
        virtual int handler (
            int signum,
            ACE_Event_Handler **event_handler = 0
            );
        virtual int initialized (void);
        virtual size_t size (void);
        virtual ACE_Lock &lock (void);
        virtual void wakeup_all_threads (void);
        virtual int owner (
            ACE_thread_t new_owner,
            ACE_thread_t *old_owner = 0
            );
        virtual int owner (ACE_thread_t *owner);
        virtual void requeue_position (int position);
        virtual int requeue_position (void);
        virtual int mask_ops (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask,
            int ops
            );
        virtual int mask_ops (
            ACE_HANDLE handle,
            ACE_Reactor_Mask mask,
            int ops
            );
        virtual int ready_ops (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask,
            int ops
            );
        virtual int ready_ops (
            ACE_HANDLE handle,
            ACE_Reactor_Mask mask,
            int ops
            );
        virtual ACE_Reactor_Impl *implementation (void);
        virtual int current_info (ACE_HANDLE handle, size_t &msg_size);
        virtual int uses_event_associations (void);
        ACE_ALLOC_HOOK_DECLARE;
        void dump (void) const;
      protected:
        virtual void implementation (ACE_Reactor_Impl *implementation);
        ACE_Reactor_Impl *implementation_;
        int delete_implementation_;
        static ACE_Reactor *reactor_;
        static int delete_reactor_;
        ACE_Reactor (const ACE_Reactor &);
        ACE_Reactor &operator = (const ACE_Reactor &);
    };

## Singleton reactor event loop management methods.

Note that these method ONLY work on the "Singleton Reactor," i.e., the one returned from `ACE_Reactor::instance`.

    static int run_event_loop (void);

    static int run_alertable_event_loop (void);

Run the event loop until the `ACE_Reactor::handle_events/ACE_Reactor::alertable_handle_events` method returns -1 or the `end_event_loop` method is invoked.

    static int run_event_loop (ACE_Time_Value &tv);

    static int run_alertable_event_loop (ACE_Time_Value &tv);

Run the event loop until the `ACE_Reactor::handle_events` or `ACE_Reactor::alertable_handle_events` methods returns -1, the `end_event_loop` method is invoked, or the `ACE_Time_Value` expires.

    static int end_event_loop (void);

Instruct the `ACE_Reactor::instance` to terminate its event loop and notifies the `ACE_Reactor::instance` so that it can wake up and close down gracefully.

    static int event_loop_done (void);

Report if the `ACE_Reactor::instance`'s event loop is finished.

    static void reset_event_loop (void);

Resets the `ACE_Reactor::end_event_loop_` static so that the `run_event_loop` method can be restarted.

    static int check_reconfiguration (void *);

The singleton reactor is used by the service_configurator. Therefore, we must check for the reconfiguration request and handle it after handling an event.

## Reactor event loop management methods.

These methods work with an instance of a reactor.

    virtual int run_reactor_event_loop (REACTOR_EVENT_HOOK = 0);

    virtual int run_alertable_reactor_event_loop (REACTOR_EVENT_HOOK = 0);

Run the event loop until the `ACE_Reactor::handle_events/ACE_Reactor::alertable_handle_events` method returns -1 or the `end_event_loop` method is invoked.

    virtual int run_reactor_event_loop (
        ACE_Time_Value &tv,
        REACTOR_EVENT_HOOK = 0
        );

    virtual int run_alertable_reactor_event_loop (
        ACE_Time_Value &tv,
        REACTOR_EVENT_HOOK = 0
        );

Run the event loop until the `ACE_Reactor::handle_events` or `ACE_Reactor::alertable_handle_events` methods returns -1, the `end_event_loop` method is invoked, or the `ACE_Time_Value` expires.

    virtual int end_reactor_event_loop (void);

Instruct the `ACE_Reactor::instance` to terminate its event loop and notifies the `ACE_Reactor::instance` so that it can wake up and close down gracefully.

    virtual int reactor_event_loop_done (void);

Report if the `ACE_Reactor::instance`'s event loop is finished.

    virtual void reset_reactor_event_loop (void);

Resets the `ACE_Reactor::end_event_loop_` static so that the `run_event_loop` method can be restarted.

    ACE_Reactor (
        ACE_Reactor_Impl *implementation = 0,
        int delete_implementation = 0
        );

Create the Reactor using `implementation`. The flag `delete_implementation` tells the Reactor whether or not to delete the `implementation` on destruction.

    virtual ~ACE_Reactor (void);

Close down and release all resources.

    virtual int open (
        size_t max_number_of_handles,
        int restart = 0,
        ACE_Sig_Handler *signal_handler = 0,
        ACE_Timer_Queue *timer_queue = 0
        );

Initialize the `ACE_Reactor` to manage `max_number_of_handles`. If `restart` is non-0 then the `ACE_Reactor`'s `handle_events` method will be restarted automatically when `EINTR` occurs. If `signal_handler` or `timer_queue` are non-0 they are used as the signal handler and timer queue, respectively.

    virtual int set_sig_handler (ACE_Sig_Handler *signal_handler);

Use a user specified signal handler instead.

    virtual int set_timer_queue (ACE_Timer_Queue *timer_queue);

Use a user specified timer queue instead. Notice that I don't think you should mess with timer queue once the Reactor is up and running.

    virtual int close (void);

Close down and release all resources.

## Event loop drivers.

    virtual int work_pending (
        const ACE_Time_Value &max_wait_time = ACE_Time_Value::zero
        );

Returns non-zero if there are I/O events "ready" for dispatching, but does not actually dispatch the event handlers. By default, don't block while checking this, i.e., "poll".

    virtual int handle_events (ACE_Time_Value *max_wait_time = 0);

    virtual int alertable_handle_events (
        ACE_Time_Value *max_wait_time = 0
        );

This event loop driver blocks for up to `max_wait_time` before returning. It will return earlier if events occur. Note that `max_wait_time` can be 0, in which case this method blocks indefinitely until events occur.

`max_wait_time` is decremented to reflect how much time this call took. For instance, if a time value of 3 seconds is passed to handle_events and an event occurs after 2 seconds, `max_wait_time` will equal 1 second. This can be used if an application wishes to handle events for some fixed amount of time.

Returns the total number of timers and I/O `ACE_Event_Handler`s that were dispatched, 0 if the `max_wait_time` elapsed without dispatching any handlers, or -1 if an error occurs.

The only difference between `alertable_handle_events` and `handle_events` is that in the alertable case, the eventloop will return when the system queues an I/O completion routine or an Asynchronous Procedure Call.

    virtual int handle_events (ACE_Time_Value &max_wait_time);

    virtual int alertable_handle_events (ACE_Time_Value &max_wait_time);

This method is just like the one above, except the `max_wait_time` value is a reference and can therefore never be NULL.

The only difference between `alertable_handle_events` and `handle_events` is that in the alertable case, the eventloop will return when the system queues an I/O completion routine or an Asynchronous Procedure Call.

## Register and remove Handlers.

    virtual int register_handler (
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask
        );

Register `event_handler` with `mask`. The I/O handle will always come from `get_handle` on the `event_handler`.

    virtual int register_handler (
        ACE_HANDLE io_handle,
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask
        );

Register `event_handler` with `mask`. The I/O handle is provided through the `io_handle` parameter.

    virtual int register_handler (
        ACE_Event_Handler *event_handler,
        ACE_HANDLE event_handle = ACE_INVALID_HANDLE
        );

Register an `event_handler` that will be notified when `event_handle` is signaled. Since no event mask is passed through this interface, it is assumed that the `event_handle` being passed in is an event handle and not an I/O handle.

Originally this interface was available for all platforms, but because ACE_HANDLE is an int on non-Win32 platforms, compilers are not able to tell the difference between register_handler(ACE_Event_Handler*,ACE_Reactor_Mask) and register_handler(ACE_Event_Handler*,ACE_HANDLE). Therefore, we have restricted this method to Win32 only.

    virtual int register_handler (
        ACE_HANDLE event_handle,
        ACE_HANDLE io_handle,
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask
        );

Register an `event_handler` that will be notified when `event_handle` is signaled. `mask` specifies the network events that the `event_handler` is interested in.

    virtual int register_handler (
        const ACE_Handle_Set &handles,
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask
        );

Register `event_handler` with all the `handles` in the `Handle_Set`.

    virtual int register_handler (
        int signum,
        ACE_Event_Handler *new_sh,
        ACE_Sig_Action *new_disp = 0,
        ACE_Event_Handler **old_sh = 0,
        ACE_Sig_Action *old_disp = 0
        );

Register `new_sh` to handle the signal `signum` using the `new_disp`. Returns the `old_sh` that was previously registered (if any), along with the `old_disp` of the signal handler.

    virtual int register_handler (
        const ACE_Sig_Set &sigset,
        ACE_Event_Handler *new_sh,
        ACE_Sig_Action *new_disp = 0
        );

Registers `new_sh` to handle a set of signals `sigset` using the `new_disp`.

    virtual int remove_handler (
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask
        );

Removes `event_handler`. Note that the I/O handle will be obtained using `get_handle` method of `event_handler` . If `mask` == `ACE_Event_Handler::DONT_CALL` then the `handle_close` method of the `event_handler` is not invoked.

    virtual int remove_handler (ACE_HANDLE handle, ACE_Reactor_Mask mask);

Removes `handle`. If `mask` == `ACE_Event_Handler::DONT_CALL` then the `handle_close` method of the associated `event_handler` is not invoked.

    virtual int remove_handler (
        const ACE_Handle_Set &handle_set,
        ACE_Reactor_Mask mask
        );

Removes all handles in `handle_set`. If `mask` == `ACE_Event_Handler::DONT_CALL` then the `handle_close` method of the associated `event_handler`s is not invoked.

    virtual int remove_handler (
        int signum,
        ACE_Sig_Action *new_disp,
        ACE_Sig_Action *old_disp = 0,
        int sigkey = -1
        );

Remove the ACE_Event_Handler currently associated with `signum`. Install the new disposition (if given) and return the previous disposition (if desired by the caller). Returns 0 on success and -1 if `signum` is invalid.

    virtual int remove_handler (const ACE_Sig_Set &sigset);

Calls `remove_handler` for every signal in `sigset`.

## Suspend and resume Handlers.

    virtual int suspend_handler (ACE_Event_Handler *event_handler);

Suspend `event_handler` temporarily. Use `event_handler-`get_handle() to get the handle.

    virtual int suspend_handler (ACE_HANDLE handle);

Suspend `handle` temporarily.

    virtual int suspend_handler (const ACE_Handle_Set &handles);

Suspend all `handles` in handle set temporarily.

    virtual int suspend_handlers (void);

Suspend all `handles` temporarily.

    virtual int resume_handler (ACE_Event_Handler *event_handler);

Resume `event_handler`. Use `event_handler-`get_handle() to get the handle.

    virtual int resume_handler (ACE_HANDLE handle);

Resume `handle`.

    virtual int resume_handler (const ACE_Handle_Set &handles);

Resume all `handles` in handle set.

    virtual int resume_handlers (void);

Resume all `handles`.

Timer management.

    virtual long schedule_timer (
        ACE_Event_Handler *event_handler,
        const void *arg,
        const ACE_Time_Value &delta,
        const ACE_Time_Value &interval = ACE_Time_Value::zero
        );

Schedule an `event_handler` that will expire after `delay` amount of time. If it expires then `arg` is passed in as the value to the `event_handler`'s `handle_timeout` callback method. If `interval` is != to `ACE_Time_Value::zero` then it is used to reschedule the `event_handler` automatically. This method returns a `timer_id` that uniquely identifies the `event_handler` in an internal list. This `timer_id` can be used to cancel an `event_handler` 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 cancel_timer (
        ACE_Event_Handler *event_handler,
        int dont_call_handle_close = 1
        );

Cancel all `Event_Handler`s that match the address of `event_handler`. Returns number of handlers cancelled.

    virtual int cancel_timer (
        long timer_id,
        const void **arg = 0,
        int dont_call_handle_close = 1
        );

Cancel the single `Event_Handler` that matches the `timer_id` value, which was returned from the schedule method. If arg is non-NULL then it will be set to point to the ``magic cookie'' argument passed in when the Event_Handler was registered. This makes it possible to free up the memory and avoid memory leaks. Returns 1 if cancellation succeeded and 0 if the `timer_id` wasn't found.

## High-level Event_Handler scheduling operations

    virtual int schedule_wakeup (
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask masks_to_be_added
        );

Add `masks_to_be_added` to the `event_handler`'s entry. `event_handler` must already have been registered.

    virtual int schedule_wakeup (
        ACE_HANDLE handle,
        ACE_Reactor_Mask masks_to_be_added
        );

Add `masks_to_be_added` to the `handle`'s entry. `event_handler` associated with `handle` must already have been registered.

    virtual int cancel_wakeup (
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask masks_to_be_cleared
        );

Clear `masks_to_be_cleared` from the `event_handler`'s entry.

    virtual int cancel_wakeup (
        ACE_HANDLE handle,
        ACE_Reactor_Mask masks_to_be_cleared
        );

Clear `masks_to_be_cleared` from the `handle`'s entry.

## Notification methods.

    virtual int notify (
        ACE_Event_Handler *event_handler = 0,
        ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK,
        ACE_Time_Value *tv = 0
        );

Notify `event_handler` of `mask` event. The `ACE_Time_Value` indicates how long to blocking trying to notify. If `timeout` == 0, the caller will block until action is possible, else will wait until the relative time specified in `timeout` elapses).

    virtual void max_notify_iterations (int iterations);

Set the maximum number of times that ACE_Reactor will iterate and dispatch the `ACE_Event_Handlers` that are passed in via the notify queue before breaking out of its `ACE_Message_Queue::dequeue` loop. By default, this is set to -1, which means "iterate until the queue is empty." Setting this to a value like "1 or 2" will increase "fairness" (and thus prevent starvation) at the expense of slightly higher dispatching overhead.

    virtual int max_notify_iterations (void);

Get the maximum number of times that the ACE_Reactor will iterate and dispatch the `ACE_Event_Handlers` that are passed in via the notify queue before breaking out of its `ACE_Message_Queue::dequeue` loop.

    virtual int handler (
        ACE_HANDLE handle,
        ACE_Reactor_Mask mask,
        ACE_Event_Handler **event_handler = 0
        );

Check to see if `handle` is associated with a valid Event_Handler bound to `mask`. Return the `event_handler` associated with this `handler` if `event_handler` != 0.

    virtual int handler (
        int signum,
        ACE_Event_Handler **event_handler = 0
        );

Check to see if `signum` is associated with a valid Event_Handler bound to a signal. Return the `event_handler` associated with this `handler` if `event_handler` != 0.

    virtual int initialized (void);

Returns true if Reactor has been successfully initialized, else false.

    virtual size_t size (void);

Returns the current size of the Reactor's internal descriptor table.

    virtual ACE_Lock &lock (void);

Returns a reference to the Reactor's internal lock.

    virtual void wakeup_all_threads (void);

Wake up all threads in waiting in the event loop

    virtual int owner (
        ACE_thread_t new_owner,
        ACE_thread_t *old_owner = 0
        );

Transfers ownership of Reactor to the `new_owner`.

    virtual int owner (ACE_thread_t *owner);

Return the ID of the "owner" thread.

    virtual void requeue_position (int position);

Set position of the owner thread.

    virtual int requeue_position (void);

Get position of the owner thread.

## Low-level wait_set mask manipulation methods.

    virtual int mask_ops (
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask,
        int ops
        );

GET/SET/ADD/CLR the dispatch mask "bit" bound with the `event_handler` and `mask`.

    virtual int mask_ops (
        ACE_HANDLE handle,
        ACE_Reactor_Mask mask,
        int ops
        );

GET/SET/ADD/CLR the dispatch MASK "bit" bound with the `handle` and `mask`.

## Low-level ready_set mask manipulation methods.

    virtual int ready_ops (
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask,
        int ops
        );

GET/SET/ADD/CLR the ready "bit" bound with the `event_handler` and `mask`.

    virtual int ready_ops (
        ACE_HANDLE handle,
        ACE_Reactor_Mask mask,
        int ops
        );

GET/SET/ADD/CLR the ready "bit" bound with the `handle` and `mask`.

    virtual ACE_Reactor_Impl *implementation (void);

Get the implementation class

    virtual int current_info (ACE_HANDLE handle, size_t &msg_size);

Returns 0, if the size of the current message has been put in `size` Returns -1, if not. ACE_HANDLE allows the reactor to check if the caller is valid. Used for CLASSIX Reactor implementation.

    virtual int uses_event_associations (void);

Return 1 if we any event associations were made by the reactor for the handles that it waits on, 0 otherwise.

    ACE_ALLOC_HOOK_DECLARE;

Declare the dynamic allocation hooks.

    void dump (void) const;

Dump the state of the object.

## AUTHOR

Irfan Pyarali

## LIBRARY

ace