libvirt/src/util/event.h

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/*
* event.h: event loop for monitoring file handles
*
* Copyright (C) 2007 Daniel P. Berrange
* Copyright (C) 2007 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#ifndef __VIR_EVENT_H__
# define __VIR_EVENT_H__
# include "internal.h"
/**
* virEventAddHandle: register a callback for monitoring file handle events
*
* @fd: file handle to monitor for events
* @events: bitset of events to watch from virEventHandleType constants
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* @cb: callback to invoke when an event occurs
* @opaque: user data to pass to callback
*
* returns -1 if the file handle cannot be registered, 0 upon success
*/
int virEventAddHandle(int fd, int events,
virEventHandleCallback cb,
void *opaque,
virFreeCallback ff);
/**
* virEventUpdateHandle: change event set for a monitored file handle
*
* @watch: watch whose file handle to update
* @events: bitset of events to watch from virEventHandleType constants
*
* Will not fail if fd exists
*/
void virEventUpdateHandle(int watch, int events);
/**
* virEventRemoveHandle: unregister a callback from a file handle
*
* @watch: watch whose file handle to remove
*
* returns -1 if the file handle was not registered, 0 upon success
*/
int virEventRemoveHandle(int watch);
/**
* virEventAddTimeout: register a callback for a timer event
*
* @frequency: time between events in milliseconds
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* @cb: callback to invoke when an event occurs
* @opaque: user data to pass to callback
*
* Setting frequency to -1 will disable the timer. Setting the frequency
* to zero will cause it to fire on every event loop iteration.
*
* returns -1 if the timer cannot be registered, a positive
* integer timer id upon success
*/
int virEventAddTimeout(int frequency,
virEventTimeoutCallback cb,
void *opaque,
virFreeCallback ff);
/**
* virEventUpdateTimeoutImpl: change frequency for a timer
*
* @timer: timer id to change
* @frequency: time between events in milliseconds
*
* Setting frequency to -1 will disable the timer. Setting the frequency
* to zero will cause it to fire on every event loop iteration.
*
* Will not fail if timer exists
*/
void virEventUpdateTimeout(int timer, int frequency);
/**
* virEventRemoveTimeout: unregister a callback for a timer
*
* @timer: the timer id to remove
*
* returns -1 if the timer was not registered, 0 upon success
*/
int virEventRemoveTimeout(int timer);
#endif /* __VIR_EVENT_H__ */