## NAME

ACE_Reactor_Impl - An abstract class for implementing the Reactor Pattern.

## SYNOPSIS

    #include <ace/Reactor_Impl.h>

    class ACE_Reactor_Impl
    {
      public:
        inline virtual ~ACE_Reactor_Impl (void);
        virtual int open (
            size_t size,
            int restart = 0,
            ACE_Sig_Handler * = 0,
            ACE_Timer_Queue * = 0,
            int disable_notify_pipe = 0,
            ACE_Reactor_Notify * = 0
            ) = 0;
        virtual int current_info (ACE_HANDLE, size_t & ) = 0;
        virtual int set_sig_handler (ACE_Sig_Handler *signal_handler) = 0;
        virtual int set_timer_queue (ACE_Timer_Queue *timer_queue) = 0;
        virtual int close (void) = 0;
        virtual int work_pending (
            const ACE_Time_Value &max_wait_time = ACE_Time_Value::zero
            ) = 0;
        virtual int handle_events (ACE_Time_Value *max_wait_time = 0) = 0;
        virtual int alertable_handle_events (
            ACE_Time_Value *max_wait_time = 0
            ) = 0;
        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 deactivated (void) = 0;
        virtual void deactivate (int do_stop) = 0;
        virtual int register_handler (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            ) = 0;
        virtual int register_handler (
            ACE_HANDLE io_handle,
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            ) = 0;
        virtual int register_handler (
            ACE_Event_Handler *event_handler,
            ACE_HANDLE event_handle = ACE_INVALID_HANDLE
            ) = 0;
        virtual int register_handler (
            ACE_HANDLE event_handle,
            ACE_HANDLE io_handle,
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            ) = 0;
        virtual int register_handler (
            const ACE_Handle_Set &handles,
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            ) = 0;
        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
            ) = 0;
        virtual int register_handler (
            const ACE_Sig_Set &sigset,
            ACE_Event_Handler *new_sh,
            ACE_Sig_Action *new_disp = 0
            ) = 0;
        virtual int remove_handler (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask
            ) = 0;
        virtual int remove_handler (
            ACE_HANDLE handle,
            ACE_Reactor_Mask mask
            ) = 0;
        virtual int remove_handler (
            const ACE_Handle_Set &handle_set,
            ACE_Reactor_Mask mask
            ) = 0;
        virtual int remove_handler (
            int signum,
            ACE_Sig_Action *new_disp,
            ACE_Sig_Action *old_disp = 0,
            int sigkey = -1
            ) = 0;
        virtual int remove_handler (const ACE_Sig_Set &sigset) = 0;
        virtual int suspend_handler (
            ACE_Event_Handler *event_handler
            ) = 0;
        virtual int suspend_handler (ACE_HANDLE handle) = 0;
        virtual int suspend_handler (const ACE_Handle_Set &handles) = 0;
        virtual int suspend_handlers (void) = 0;
        virtual int resume_handler (ACE_Event_Handler *event_handler) = 0;
        virtual int resume_handler (ACE_HANDLE handle) = 0;
        virtual int resume_handler (const ACE_Handle_Set &handles) = 0;
        virtual int resume_handlers (void) = 0;
        virtual int uses_event_associations (void) = 0;
        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
            ) = 0;
        virtual int cancel_timer (
            ACE_Event_Handler *event_handler,
            int dont_call_handle_close = 1
            ) = 0;
        virtual int cancel_timer (
            long timer_id,
            const void **arg = 0,
            int dont_call_handle_close = 1
            ) = 0;
        virtual int schedule_wakeup (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask masks_to_be_added
            ) = 0;
        virtual int schedule_wakeup (
            ACE_HANDLE handle,
            ACE_Reactor_Mask masks_to_be_added
            ) = 0;
        virtual int cancel_wakeup (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask masks_to_be_cleared
            ) = 0;
        virtual int cancel_wakeup (
            ACE_HANDLE handle,
            ACE_Reactor_Mask masks_to_be_cleared
            ) = 0;
        virtual int notify (
            ACE_Event_Handler *event_handler = 0,
            ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK,
            ACE_Time_Value * = 0
            ) = 0;
        virtual void max_notify_iterations (int) = 0;
        virtual int max_notify_iterations (void) = 0;
        virtual int handler (
            ACE_HANDLE handle,
            ACE_Reactor_Mask mask,
            ACE_Event_Handler **event_handler = 0
            ) = 0;
        virtual int handler (int signum, ACE_Event_Handler ** = 0) = 0;
        virtual int initialized (void) = 0;
        virtual size_t size (void) = 0;
        virtual ACE_Lock &lock (void) = 0;
        virtual void wakeup_all_threads (void) = 0;
        virtual int owner (
            ACE_thread_t new_owner,
            ACE_thread_t *old_owner = 0
            ) = 0;
        virtual int owner (ACE_thread_t *owner) = 0;
        virtual void requeue_position (int) = 0;
        virtual int requeue_position (void) = 0;
        virtual int mask_ops (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask,
            int ops
            ) = 0;
        virtual int mask_ops (
            ACE_HANDLE handle,
            ACE_Reactor_Mask mask,
            int ops
            ) = 0;
        virtual int ready_ops (
            ACE_Event_Handler *event_handler,
            ACE_Reactor_Mask mask,
            int ops
            ) = 0;
        virtual int ready_ops (
            ACE_HANDLE handle,
            ACE_Reactor_Mask,
            int ops
            ) = 0;
        virtual void dump (void) const = 0;
        ACE_ALLOC_HOOK_DECLARE;
    };

## Event loop drivers.

    virtual int work_pending (
        const ACE_Time_Value &max_wait_time = ACE_Time_Value::zero
        ) = 0;

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) = 0;

    virtual int alertable_handle_events (
        ACE_Time_Value *max_wait_time = 0
        ) = 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 `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) = 0;

    virtual int alertable_handle_events (
        ACE_Time_Value &max_wait_time
        ) = 0;

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.

## Event handling control.

    virtual int deactivated (void) = 0;

Return the status of Reactor. If this function returns 0, the reactor is actively handling events. If it returns non-zero, `handling_events` and `handle_alertable_events` return -1 immediately.

    virtual void deactivate (int do_stop) = 0;

Control whether the Reactor will handle any more incoming events or not. If `do_stop` == 1, the Reactor will be disabled. By default, a reactor is in active state and can be deactivated/reactived as wish.

## Register and remove Handlers.

    virtual int register_handler (
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask
        ) = 0;

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
        ) = 0;

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

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_Event_Handler *event_handler,
        ACE_HANDLE event_handle = ACE_INVALID_HANDLE
        ) = 0;

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.

    virtual int register_handler (
        ACE_HANDLE event_handle,
        ACE_HANDLE io_handle,
        ACE_Event_Handler *event_handler,
        ACE_Reactor_Mask mask
        ) = 0;

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
        ) = 0;

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
        ) = 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
        ) = 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
        ) = 0;

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
        ) = 0;

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
        ) = 0;

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
        ) = 0;

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) = 0;

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

## Suspend and resume Handlers.

    virtual int suspend_handler (ACE_Event_Handler *event_handler) = 0;

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

    virtual int suspend_handler (ACE_HANDLE handle) = 0;

Suspend `handle` temporarily.

    virtual int suspend_handler (const ACE_Handle_Set &handles) = 0;

Suspend all `handles` in handle set temporarily.

    virtual int suspend_handlers (void) = 0;

Suspend all `handles` temporarily.

    virtual int resume_handler (ACE_Event_Handler *event_handler) = 0;

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

    virtual int resume_handler (ACE_HANDLE handle) = 0;

Resume `handle`.

    virtual int resume_handler (const ACE_Handle_Set &handles) = 0;

Resume all `handles` in handle set.

    virtual int resume_handlers (void) = 0;

Resume all `handles`.

    virtual int uses_event_associations (void) = 0;

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

If we need to reset handles returned from accept/connect. 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
        ) = 0;

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
        ) = 0;

Cancel all Event_Handlers 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
        ) = 0;

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
        ) = 0;

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
        ) = 0;

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
        ) = 0;

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
        ) = 0;

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 * = 0
        ) = 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) = 0;

Set the maximum number of times that ACE_Reactor_Impl 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) = 0;

Get the maximum number of times that the ACE_Reactor_Impl 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
        ) = 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 ** = 0) = 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) = 0;

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

    virtual size_t size (void) = 0;

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

    virtual ACE_Lock &lock (void) = 0;

Returns a reference to the Reactor's internal lock.

    virtual void wakeup_all_threads (void) = 0;

Wake up all threads in waiting in the event loop

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

Transfers ownership of Reactor_Impl to the `new_owner`.

    virtual int owner (ACE_thread_t *owner) = 0;

Return the ID of the "owner" thread.

    virtual void requeue_position (int) = 0;

Set position of the owner thread.

    virtual int requeue_position (void) = 0;

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
        ) = 0;

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
        ) = 0;

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
        ) = 0;

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

    virtual int ready_ops (
        ACE_HANDLE handle,
        ACE_Reactor_Mask,
        int ops
        ) = 0;

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

    virtual void dump (void) const = 0;

Dump the state of an object.

    ACE_ALLOC_HOOK_DECLARE;

Declare the dynamic allocation hooks.

## AUTHOR

Irfan Pyarali

## LIBRARY

ace