Adding upstream version 1.0.18.upstream/1.0.18upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1672 insertions, 0 deletions

diff --git a/libevent/include/event2/event.h b/libevent/include/event2/event.h
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+/*
+ * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
+ * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef EVENT2_EVENT_H_INCLUDED_
+#define EVENT2_EVENT_H_INCLUDED_
+
+/**
+   @mainpage
+
+  @section intro Introduction
+
+  Libevent is an event notification library for developing scalable network
+  servers.  The Libevent API provides a mechanism to execute a callback
+  function when a specific event occurs on a file descriptor or after a
+  timeout has been reached. Furthermore, Libevent also support callbacks due
+  to signals or regular timeouts.
+
+  Libevent is meant to replace the event loop found in event driven network
+  servers. An application just needs to call event_base_dispatch() and then add or
+  remove events dynamically without having to change the event loop.
+
+
+  Currently, Libevent supports /dev/poll, kqueue(2), select(2), poll(2),
+  epoll(4), and evports. The internal event mechanism is completely
+  independent of the exposed event API, and a simple update of Libevent can
+  provide new functionality without having to redesign the applications. As a
+  result, Libevent allows for portable application development and provides
+  the most scalable event notification mechanism available on an operating
+  system.  Libevent can also be used for multithreaded programs.  Libevent
+  should compile on Linux, *BSD, Mac OS X, Solaris and, Windows.
+
+  @section usage Standard usage
+
+  Every program that uses Libevent must include the <event2/event.h>
+  header, and pass the -levent flag to the linker.  (You can instead link
+  -levent_core if you only want the main event and buffered IO-based code,
+  and don't want to link any protocol code.)
+
+  @section setup Library setup
+
+  Before you call any other Libevent functions, you need to set up the
+  library.  If you're going to use Libevent from multiple threads in a
+  multithreaded application, you need to initialize thread support --
+  typically by using evthread_use_pthreads() or
+  evthread_use_windows_threads().  See <event2/thread.h> for more
+  information.
+
+  This is also the point where you can replace Libevent's memory
+  management functions with event_set_mem_functions, and enable debug mode
+  with event_enable_debug_mode().
+
+  @section base Creating an event base
+
+  Next, you need to create an event_base structure, using event_base_new()
+  or event_base_new_with_config().  The event_base is responsible for
+  keeping track of which events are "pending" (that is to say, being
+  watched to see if they become active) and which events are "active".
+  Every event is associated with a single event_base.
+
+  @section event Event notification
+
+  For each file descriptor that you wish to monitor, you must create an
+  event structure with event_new().  (You may also declare an event
+  structure and call event_assign() to initialize the members of the
+  structure.)  To enable notification, you add the structure to the list
+  of monitored events by calling event_add().  The event structure must
+  remain allocated as long as it is active, so it should generally be
+  allocated on the heap.
+
+  @section loop Dispatching events.
+
+  Finally, you call event_base_dispatch() to loop and dispatch events.
+  You can also use event_base_loop() for more fine-grained control.
+
+  Currently, only one thread can be dispatching a given event_base at a
+  time.  If you want to run events in multiple threads at once, you can
+  either have a single event_base whose events add work to a work queue,
+  or you can create multiple event_base objects.
+
+  @section bufferevent I/O Buffers
+
+  Libevent provides a buffered I/O abstraction on top of the regular event
+  callbacks. This abstraction is called a bufferevent. A bufferevent
+  provides input and output buffers that get filled and drained
+  automatically. The user of a buffered event no longer deals directly
+  with the I/O, but instead is reading from input and writing to output
+  buffers.
+
+  Once initialized via bufferevent_socket_new(), the bufferevent structure
+  can be used repeatedly with bufferevent_enable() and
+  bufferevent_disable().  Instead of reading and writing directly to a
+  socket, you would call bufferevent_read() and bufferevent_write().
+
+  When read enabled the bufferevent will try to read from the file descriptor
+  and call the read callback. The write callback is executed whenever the
+  output buffer is drained below the write low watermark, which is 0 by
+  default.
+
+  See <event2/bufferevent*.h> for more information.
+
+  @section timers Timers
+
+  Libevent can also be used to create timers that invoke a callback after a
+  certain amount of time has expired. The evtimer_new() macro returns
+  an event struct to use as a timer. To activate the timer, call
+  evtimer_add(). Timers can be deactivated by calling evtimer_del().
+  (These macros are thin wrappers around event_new(), event_add(),
+  and event_del(); you can also use those instead.)
+
+  @section evdns Asynchronous DNS resolution
+
+  Libevent provides an asynchronous DNS resolver that should be used instead
+  of the standard DNS resolver functions.  See the <event2/dns.h>
+  functions for more detail.
+
+  @section evhttp Event-driven HTTP servers
+
+  Libevent provides a very simple event-driven HTTP server that can be
+  embedded in your program and used to service HTTP requests.
+
+  To use this capability, you need to include the <event2/http.h> header in your
+  program.  See that header for more information.
+
+  @section evrpc A framework for RPC servers and clients
+
+  Libevent provides a framework for creating RPC servers and clients.  It
+  takes care of marshaling and unmarshaling all data structures.
+
+  @section api API Reference
+
+  To browse the complete documentation of the libevent API, click on any of
+  the following links.
+
+  event2/event.h
+  The primary libevent header
+
+  event2/thread.h
+  Functions for use by multithreaded programs
+
+  event2/buffer.h and event2/bufferevent.h
+  Buffer management for network reading and writing
+
+  event2/util.h
+  Utility functions for portable nonblocking network code
+
+  event2/dns.h
+  Asynchronous DNS resolution
+
+  event2/http.h
+  An embedded libevent-based HTTP server
+
+  event2/rpc.h
+  A framework for creating RPC servers and clients
+
+ */
+
+/** @file event2/event.h
+
+  Core functions for waiting for and receiving events, and using event bases.
+*/
+
+#include <event2/visibility.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <event2/event-config.h>
+#ifdef EVENT__HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef EVENT__HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#include <stdio.h>
+
+/* For int types. */
+#include <event2/util.h>
+
+/**
+ * Structure to hold information and state for a Libevent dispatch loop.
+ *
+ * The event_base lies at the center of Libevent; every application will
+ * have one.  It keeps track of all pending and active events, and
+ * notifies your application of the active ones.
+ *
+ * This is an opaque structure; you can allocate one using
+ * event_base_new() or event_base_new_with_config().
+ *
+ * @see event_base_new(), event_base_free(), event_base_loop(),
+ *    event_base_new_with_config()
+ */
+struct event_base
+#ifdef EVENT_IN_DOXYGEN_
+{/*Empty body so that doxygen will generate documentation here.*/}
+#endif
+;
+
+/**
+ * @struct event
+ *
+ * Structure to represent a single event.
+ *
+ * An event can have some underlying condition it represents: a socket
+ * becoming readable or writeable (or both), or a signal becoming raised.
+ * (An event that represents no underlying condition is still useful: you
+ * can use one to implement a timer, or to communicate between threads.)
+ *
+ * Generally, you can create events with event_new(), then make them
+ * pending with event_add().  As your event_base runs, it will run the
+ * callbacks of an events whose conditions are triggered.  When you no
+ * longer want the event, free it with event_free().
+ *
+ * In more depth:
+ *
+ * An event may be "pending" (one whose condition we are watching),
+ * "active" (one whose condition has triggered and whose callback is about
+ * to run), neither, or both.  Events come into existence via
+ * event_assign() or event_new(), and are then neither active nor pending.
+ *
+ * To make an event pending, pass it to event_add().  When doing so, you
+ * can also set a timeout for the event.
+ *
+ * Events become active during an event_base_loop() call when either their
+ * condition has triggered, or when their timeout has elapsed.  You can
+ * also activate an event manually using event_active().  The even_base
+ * loop will run the callbacks of active events; after it has done so, it
+ * marks them as no longer active.
+ *
+ * You can make an event non-pending by passing it to event_del().  This
+ * also makes the event non-active.
+ *
+ * Events can be "persistent" or "non-persistent".  A non-persistent event
+ * becomes non-pending as soon as it is triggered: thus, it only runs at
+ * most once per call to event_add().  A persistent event remains pending
+ * even when it becomes active: you'll need to event_del() it manually in
+ * order to make it non-pending.  When a persistent event with a timeout
+ * becomes active, its timeout is reset: this means you can use persistent
+ * events to implement periodic timeouts.
+ *
+ * This should be treated as an opaque structure; you should never read or
+ * write any of its fields directly.  For backward compatibility with old
+ * code, it is defined in the event2/event_struct.h header; including this
+ * header may make your code incompatible with other versions of Libevent.
+ *
+ * @see event_new(), event_free(), event_assign(), event_get_assignment(),
+ *    event_add(), event_del(), event_active(), event_pending(),
+ *    event_get_fd(), event_get_base(), event_get_events(),
+ *    event_get_callback(), event_get_callback_arg(),
+ *    event_priority_set()
+ */
+struct event
+#ifdef EVENT_IN_DOXYGEN_
+{/*Empty body so that doxygen will generate documentation here.*/}
+#endif
+;
+
+/**
+ * Configuration for an event_base.
+ *
+ * There are many options that can be used to alter the behavior and
+ * implementation of an event_base.  To avoid having to pass them all in a
+ * complex many-argument constructor, we provide an abstract data type
+ * where you set up configuration information before passing it to
+ * event_base_new_with_config().
+ *
+ * @see event_config_new(), event_config_free(), event_base_new_with_config(),
+ *   event_config_avoid_method(), event_config_require_features(),
+ *   event_config_set_flag(), event_config_set_num_cpus_hint()
+ */
+struct event_config
+#ifdef EVENT_IN_DOXYGEN_
+{/*Empty body so that doxygen will generate documentation here.*/}
+#endif
+;
+
+/**
+ * Enable some relatively expensive debugging checks in Libevent that
+ * would normally be turned off.  Generally, these checks cause code that
+ * would otherwise crash mysteriously to fail earlier with an assertion
+ * failure.  Note that this method MUST be called before any events or
+ * event_bases have been created.
+ *
+ * Debug mode can currently catch the following errors:
+ *    An event is re-assigned while it is added
+ *    Any function is called on a non-assigned event
+ *
+ * Note that debugging mode uses memory to track every event that has been
+ * initialized (via event_assign, event_set, or event_new) but not yet
+ * released (via event_free or event_debug_unassign).  If you want to use
+ * debug mode, and you find yourself running out of memory, you will need
+ * to use event_debug_unassign to explicitly stop tracking events that
+ * are no longer considered set-up.
+ *
+ * @see event_debug_unassign()
+ */
+EVENT2_EXPORT_SYMBOL
+void event_enable_debug_mode(void);
+
+/**
+ * When debugging mode is enabled, informs Libevent that an event should no
+ * longer be considered as assigned. When debugging mode is not enabled, does
+ * nothing.
+ *
+ * This function must only be called on a non-added event.
+ *
+ * @see event_enable_debug_mode()
+ */
+EVENT2_EXPORT_SYMBOL
+void event_debug_unassign(struct event *);
+
+/**
+ * Create and return a new event_base to use with the rest of Libevent.
+ *
+ * @return a new event_base on success, or NULL on failure.
+ *
+ * @see event_base_free(), event_base_new_with_config()
+ */
+EVENT2_EXPORT_SYMBOL
+struct event_base *event_base_new(void);
+
+/**
+  Reinitialize the event base after a fork
+
+  Some event mechanisms do not survive across fork.   The event base needs
+  to be reinitialized with the event_reinit() function.
+
+  @param base the event base that needs to be re-initialized
+  @return 0 if successful, or -1 if some events could not be re-added.
+  @see event_base_new()
+*/
+EVENT2_EXPORT_SYMBOL
+int event_reinit(struct event_base *base);
+
+/**
+   Event dispatching loop
+
+  This loop will run the event base until either there are no more pending or
+  active, or until something calls event_base_loopbreak() or
+  event_base_loopexit().
+
+  @param base the event_base structure returned by event_base_new() or
+     event_base_new_with_config()
+  @return 0 if successful, -1 if an error occurred, or 1 if we exited because
+     no events were pending or active.
+  @see event_base_loop()
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_dispatch(struct event_base *);
+
+/**
+ Get the kernel event notification mechanism used by Libevent.
+
+ @param eb the event_base structure returned by event_base_new()
+ @return a string identifying the kernel event mechanism (kqueue, epoll, etc.)
+ */
+EVENT2_EXPORT_SYMBOL
+const char *event_base_get_method(const struct event_base *);
+
+/**
+   Gets all event notification mechanisms supported by Libevent.
+
+   This functions returns the event mechanism in order preferred by
+   Libevent.  Note that this list will include all backends that
+   Libevent has compiled-in support for, and will not necessarily check
+   your OS to see whether it has the required resources.
+
+   @return an array with pointers to the names of support methods.
+     The end of the array is indicated by a NULL pointer.  If an
+     error is encountered NULL is returned.
+*/
+EVENT2_EXPORT_SYMBOL
+const char **event_get_supported_methods(void);
+
+/** Query the current monotonic time from a the timer for a struct
+ * event_base.
+ */
+EVENT2_EXPORT_SYMBOL
+int event_gettime_monotonic(struct event_base *base, struct timeval *tp);
+
+/**
+   @name event type flag
+
+   Flags to pass to event_base_get_num_events() to specify the kinds of events
+   we want to aggregate counts for
+*/
+/**@{*/
+/** count the number of active events, which have been triggered.*/
+#define EVENT_BASE_COUNT_ACTIVE                1U
+/** count the number of virtual events, which is used to represent an internal
+ * condition, other than a pending event, that keeps the loop from exiting. */
+#define EVENT_BASE_COUNT_VIRTUAL       2U
+/** count the number of events which have been added to event base, including
+ * internal events. */
+#define EVENT_BASE_COUNT_ADDED         4U
+/**@}*/
+
+/**
+   Gets the number of events in event_base, as specified in the flags.
+
+   Since event base has some internal events added to make some of its
+   functionalities work, EVENT_BASE_COUNT_ADDED may return more than the
+   number of events you added using event_add().
+
+   If you pass EVENT_BASE_COUNT_ACTIVE and EVENT_BASE_COUNT_ADDED together, an
+   active event will be counted twice. However, this might not be the case in
+   future libevent versions.  The return value is an indication of the work
+   load, but the user shouldn't rely on the exact value as this may change in
+   the future.
+
+   @param eb the event_base structure returned by event_base_new()
+   @param flags a bitwise combination of the kinds of events to aggregate
+       counts for
+   @return the number of events specified in the flags
+*/
+EVENT2_EXPORT_SYMBOL
+int event_base_get_num_events(struct event_base *, unsigned int);
+
+/**
+  Get the maximum number of events in a given event_base as specified in the
+  flags.
+
+  @param eb the event_base structure returned by event_base_new()
+  @param flags a bitwise combination of the kinds of events to aggregate
+         counts for
+  @param clear option used to reset the maximum count.
+  @return the number of events specified in the flags
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_get_max_events(struct event_base *, unsigned int, int);
+
+/**
+   Allocates a new event configuration object.
+
+   The event configuration object can be used to change the behavior of
+   an event base.
+
+   @return an event_config object that can be used to store configuration, or
+     NULL if an error is encountered.
+   @see event_base_new_with_config(), event_config_free(), event_config
+*/
+EVENT2_EXPORT_SYMBOL
+struct event_config *event_config_new(void);
+
+/**
+   Deallocates all memory associated with an event configuration object
+
+   @param cfg the event configuration object to be freed.
+*/
+EVENT2_EXPORT_SYMBOL
+void event_config_free(struct event_config *cfg);
+
+/**
+   Enters an event method that should be avoided into the configuration.
+
+   This can be used to avoid event mechanisms that do not support certain
+   file descriptor types, or for debugging to avoid certain event
+   mechanisms.  An application can make use of multiple event bases to
+   accommodate incompatible file descriptor types.
+
+   @param cfg the event configuration object
+   @param method the name of the event method to avoid
+   @return 0 on success, -1 on failure.
+*/
+EVENT2_EXPORT_SYMBOL
+int event_config_avoid_method(struct event_config *cfg, const char *method);
+
+/**
+   A flag used to describe which features an event_base (must) provide.
+
+   Because of OS limitations, not every Libevent backend supports every
+   possible feature.  You can use this type with
+   event_config_require_features() to tell Libevent to only proceed if your
+   event_base implements a given feature, and you can receive this type from
+   event_base_get_features() to see which features are available.
+*/
+enum event_method_feature {
+    /** Require an event method that allows edge-triggered events with EV_ET. */
+    EV_FEATURE_ET = 0x01,
+    /** Require an event method where having one event triggered among
+     * many is [approximately] an O(1) operation. This excludes (for
+     * example) select and poll, which are approximately O(N) for N
+     * equal to the total number of possible events. */
+    EV_FEATURE_O1 = 0x02,
+    /** Require an event method that allows file descriptors as well as
+     * sockets. */
+    EV_FEATURE_FDS = 0x04,
+    /** Require an event method that allows you to use EV_CLOSED to detect
+     * connection close without the necessity of reading all the pending data.
+     *
+     * Methods that do support EV_CLOSED may not be able to provide support on
+     * all kernel versions.
+     **/
+    EV_FEATURE_EARLY_CLOSE = 0x08
+};
+
+/**
+   A flag passed to event_config_set_flag().
+
+    These flags change the behavior of an allocated event_base.
+
+    @see event_config_set_flag(), event_base_new_with_config(),
+       event_method_feature
+ */
+enum event_base_config_flag {
+	/** Do not allocate a lock for the event base, even if we have
+	    locking set up.
+
+	    Setting this option will make it unsafe and nonfunctional to call
+	    functions on the base concurrently from multiple threads.
+	*/
+	EVENT_BASE_FLAG_NOLOCK = 0x01,
+	/** Do not check the EVENT_* environment variables when configuring
+	    an event_base  */
+	EVENT_BASE_FLAG_IGNORE_ENV = 0x02,
+	/** Windows only: enable the IOCP dispatcher at startup
+
+	    If this flag is set then bufferevent_socket_new() and
+	    evconn_listener_new() will use IOCP-backed implementations
+	    instead of the usual select-based one on Windows.
+	 */
+	EVENT_BASE_FLAG_STARTUP_IOCP = 0x04,
+	/** Instead of checking the current time every time the event loop is
+	    ready to run timeout callbacks, check after each timeout callback.
+	 */
+	EVENT_BASE_FLAG_NO_CACHE_TIME = 0x08,
+
+	/** If we are using the epoll backend, this flag says that it is
+	    safe to use Libevent's internal change-list code to batch up
+	    adds and deletes in order to try to do as few syscalls as
+	    possible.  Setting this flag can make your code run faster, but
+	    it may trigger a Linux bug: it is not safe to use this flag
+	    if you have any fds cloned by dup() or its variants.  Doing so
+	    will produce strange and hard-to-diagnose bugs.
+
+	    This flag can also be activated by setting the
+	    EVENT_EPOLL_USE_CHANGELIST environment variable.
+
+	    This flag has no effect if you wind up using a backend other than
+	    epoll.
+	 */
+	EVENT_BASE_FLAG_EPOLL_USE_CHANGELIST = 0x10,
+
+	/** Ordinarily, Libevent implements its time and timeout code using
+	    the fastest monotonic timer that we have.  If this flag is set,
+	    however, we use less efficient more precise timer, assuming one is
+	    present.
+	 */
+	EVENT_BASE_FLAG_PRECISE_TIMER = 0x20
+};
+
+/**
+   Return a bitmask of the features implemented by an event base.  This
+   will be a bitwise OR of one or more of the values of
+   event_method_feature
+
+   @see event_method_feature
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_get_features(const struct event_base *base);
+
+/**
+   Enters a required event method feature that the application demands.
+
+   Note that not every feature or combination of features is supported
+   on every platform.  Code that requests features should be prepared
+   to handle the case where event_base_new_with_config() returns NULL, as in:
+   <pre>
+     event_config_require_features(cfg, EV_FEATURE_ET);
+     base = event_base_new_with_config(cfg);
+     if (base == NULL) {
+       // We can't get edge-triggered behavior here.
+       event_config_require_features(cfg, 0);
+       base = event_base_new_with_config(cfg);
+     }
+   </pre>
+
+   @param cfg the event configuration object
+   @param feature a bitfield of one or more event_method_feature values.
+          Replaces values from previous calls to this function.
+   @return 0 on success, -1 on failure.
+   @see event_method_feature, event_base_new_with_config()
+*/
+EVENT2_EXPORT_SYMBOL
+int event_config_require_features(struct event_config *cfg, int feature);
+
+/**
+ * Sets one or more flags to configure what parts of the eventual event_base
+ * will be initialized, and how they'll work.
+ *
+ * @see event_base_config_flags, event_base_new_with_config()
+ **/
+EVENT2_EXPORT_SYMBOL
+int event_config_set_flag(struct event_config *cfg, int flag);
+
+/**
+ * Records a hint for the number of CPUs in the system. This is used for
+ * tuning thread pools, etc, for optimal performance.  In Libevent 2.0,
+ * it is only on Windows, and only when IOCP is in use.
+ *
+ * @param cfg the event configuration object
+ * @param cpus the number of cpus
+ * @return 0 on success, -1 on failure.
+ */
+EVENT2_EXPORT_SYMBOL
+int event_config_set_num_cpus_hint(struct event_config *cfg, int cpus);
+
+/**
+ * Record an interval and/or a number of callbacks after which the event base
+ * should check for new events.  By default, the event base will run as many
+ * events are as activated at the highest activated priority before checking
+ * for new events.  If you configure it by setting max_interval, it will check
+ * the time after each callback, and not allow more than max_interval to
+ * elapse before checking for new events.  If you configure it by setting
+ * max_callbacks to a value >= 0, it will run no more than max_callbacks
+ * callbacks before checking for new events.
+ *
+ * This option can decrease the latency of high-priority events, and
+ * avoid priority inversions where multiple low-priority events keep us from
+ * polling for high-priority events, but at the expense of slightly decreasing
+ * the throughput.  Use it with caution!
+ *
+ * @param cfg The event_base configuration object.
+ * @param max_interval An interval after which Libevent should stop running
+ *     callbacks and check for more events, or NULL if there should be
+ *     no such interval.
+ * @param max_callbacks A number of callbacks after which Libevent should
+ *     stop running callbacks and check for more events, or -1 if there
+ *     should be no such limit.
+ * @param min_priority A priority below which max_interval and max_callbacks
+ *     should not be enforced.  If this is set to 0, they are enforced
+ *     for events of every priority; if it's set to 1, they're enforced
+ *     for events of priority 1 and above, and so on.
+ * @return 0 on success, -1 on failure.
+ **/
+EVENT2_EXPORT_SYMBOL
+int event_config_set_max_dispatch_interval(struct event_config *cfg,
+    const struct timeval *max_interval, int max_callbacks,
+    int min_priority);
+
+/**
+  Initialize the event API.
+
+  Use event_base_new_with_config() to initialize a new event base, taking
+  the specified configuration under consideration.  The configuration object
+  can currently be used to avoid certain event notification mechanisms.
+
+  @param cfg the event configuration object
+  @return an initialized event_base that can be used to registering events,
+     or NULL if no event base can be created with the requested event_config.
+  @see event_base_new(), event_base_free(), event_init(), event_assign()
+*/
+EVENT2_EXPORT_SYMBOL
+struct event_base *event_base_new_with_config(const struct event_config *);
+
+/**
+  Deallocate all memory associated with an event_base, and free the base.
+
+  Note that this function will not close any fds or free any memory passed
+  to event_new as the argument to callback.
+
+  If there are any pending finalizer callbacks, this function will invoke
+  them.
+
+  @param eb an event_base to be freed
+ */
+EVENT2_EXPORT_SYMBOL
+void event_base_free(struct event_base *);
+
+/**
+   As event_base_free, but do not run finalizers.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_base_free_nofinalize(struct event_base *);
+
+/** @name Log severities
+ */
+/**@{*/
+#define EVENT_LOG_DEBUG 0
+#define EVENT_LOG_MSG   1
+#define EVENT_LOG_WARN  2
+#define EVENT_LOG_ERR   3
+/**@}*/
+
+/* Obsolete names: these are deprecated, but older programs might use them.
+ * They violate the reserved-identifier namespace. */
+#define _EVENT_LOG_DEBUG EVENT_LOG_DEBUG
+#define _EVENT_LOG_MSG EVENT_LOG_MSG
+#define _EVENT_LOG_WARN EVENT_LOG_WARN
+#define _EVENT_LOG_ERR EVENT_LOG_ERR
+
+/**
+  A callback function used to intercept Libevent's log messages.
+
+  @see event_set_log_callback
+ */
+typedef void (*event_log_cb)(int severity, const char *msg);
+/**
+  Redirect Libevent's log messages.
+
+  @param cb a function taking two arguments: an integer severity between
+     EVENT_LOG_DEBUG and EVENT_LOG_ERR, and a string.  If cb is NULL,
+	 then the default log is used.
+
+  NOTE: The function you provide *must not* call any other libevent
+  functionality.  Doing so can produce undefined behavior.
+  */
+EVENT2_EXPORT_SYMBOL
+void event_set_log_callback(event_log_cb cb);
+
+/**
+   A function to be called if Libevent encounters a fatal internal error.
+
+   @see event_set_fatal_callback
+ */
+typedef void (*event_fatal_cb)(int err);
+
+/**
+ Override Libevent's behavior in the event of a fatal internal error.
+
+ By default, Libevent will call exit(1) if a programming error makes it
+ impossible to continue correct operation.  This function allows you to supply
+ another callback instead.  Note that if the function is ever invoked,
+ something is wrong with your program, or with Libevent: any subsequent calls
+ to Libevent may result in undefined behavior.
+
+ Libevent will (almost) always log an EVENT_LOG_ERR message before calling
+ this function; look at the last log message to see why Libevent has died.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_set_fatal_callback(event_fatal_cb cb);
+
+#define EVENT_DBG_ALL 0xffffffffu
+#define EVENT_DBG_NONE 0
+
+/**
+ Turn on debugging logs and have them sent to the default log handler.
+
+ This is a global setting; if you are going to call it, you must call this
+ before any calls that create an event-base.  You must call it before any
+ multithreaded use of Libevent.
+
+ Debug logs are verbose.
+
+ @param which Controls which debug messages are turned on.  This option is
+   unused for now; for forward compatibility, you must pass in the constant
+   "EVENT_DBG_ALL" to turn debugging logs on, or "EVENT_DBG_NONE" to turn
+   debugging logs off.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_enable_debug_logging(ev_uint32_t which);
+
+/**
+  Associate a different event base with an event.
+
+  The event to be associated must not be currently active or pending.
+
+  @param eb the event base
+  @param ev the event
+  @return 0 on success, -1 on failure.
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_set(struct event_base *, struct event *);
+
+/** @name Loop flags
+
+    These flags control the behavior of event_base_loop().
+ */
+/**@{*/
+/** Block until we have an active event, then exit once all active events
+ * have had their callbacks run. */
+#define EVLOOP_ONCE	0x01
+/** Do not block: see which events are ready now, run the callbacks
+ * of the highest-priority ones, then exit. */
+#define EVLOOP_NONBLOCK	0x02
+/** Do not exit the loop because we have no pending events.  Instead, keep
+ * running until event_base_loopexit() or event_base_loopbreak() makes us
+ * stop.
+ */
+#define EVLOOP_NO_EXIT_ON_EMPTY 0x04
+/**@}*/
+
+/**
+  Wait for events to become active, and run their callbacks.
+
+  This is a more flexible version of event_base_dispatch().
+
+  By default, this loop will run the event base until either there are no more
+  pending or active events, or until something calls event_base_loopbreak() or
+  event_base_loopexit().  You can override this behavior with the 'flags'
+  argument.
+
+  @param eb the event_base structure returned by event_base_new() or
+     event_base_new_with_config()
+  @param flags any combination of EVLOOP_ONCE | EVLOOP_NONBLOCK
+  @return 0 if successful, -1 if an error occurred, or 1 if we exited because
+     no events were pending or active.
+  @see event_base_loopexit(), event_base_dispatch(), EVLOOP_ONCE,
+     EVLOOP_NONBLOCK
+  */
+EVENT2_EXPORT_SYMBOL
+int event_base_loop(struct event_base *, int);
+
+/**
+  Exit the event loop after the specified time
+
+  The next event_base_loop() iteration after the given timer expires will
+  complete normally (handling all queued events) then exit without
+  blocking for events again.
+
+  Subsequent invocations of event_base_loop() will proceed normally.
+
+  @param eb the event_base structure returned by event_init()
+  @param tv the amount of time after which the loop should terminate,
+    or NULL to exit after running all currently active events.
+  @return 0 if successful, or -1 if an error occurred
+  @see event_base_loopbreak()
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_loopexit(struct event_base *, const struct timeval *);
+
+/**
+  Abort the active event_base_loop() immediately.
+
+  event_base_loop() will abort the loop after the next event is completed;
+  event_base_loopbreak() is typically invoked from this event's callback.
+  This behavior is analogous to the "break;" statement.
+
+  Subsequent invocations of event_base_loop() will proceed normally.
+
+  @param eb the event_base structure returned by event_init()
+  @return 0 if successful, or -1 if an error occurred
+  @see event_base_loopexit()
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_loopbreak(struct event_base *);
+
+/**
+  Tell the active event_base_loop() to scan for new events immediately.
+
+  Calling this function makes the currently active event_base_loop()
+  start the loop over again (scanning for new events) after the current
+  event callback finishes.  If the event loop is not running, this
+  function has no effect.
+
+  event_base_loopbreak() is typically invoked from this event's callback.
+  This behavior is analogous to the "continue;" statement.
+
+  Subsequent invocations of event loop will proceed normally.
+
+  @param eb the event_base structure returned by event_init()
+  @return 0 if successful, or -1 if an error occurred
+  @see event_base_loopbreak()
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_loopcontinue(struct event_base *);
+
+/**
+  Checks if the event loop was told to exit by event_base_loopexit().
+
+  This function will return true for an event_base at every point after
+  event_loopexit() is called, until the event loop is next entered.
+
+  @param eb the event_base structure returned by event_init()
+  @return true if event_base_loopexit() was called on this event base,
+    or 0 otherwise
+  @see event_base_loopexit()
+  @see event_base_got_break()
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_got_exit(struct event_base *);
+
+/**
+  Checks if the event loop was told to abort immediately by event_base_loopbreak().
+
+  This function will return true for an event_base at every point after
+  event_base_loopbreak() is called, until the event loop is next entered.
+
+  @param eb the event_base structure returned by event_init()
+  @return true if event_base_loopbreak() was called on this event base,
+    or 0 otherwise
+  @see event_base_loopbreak()
+  @see event_base_got_exit()
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_got_break(struct event_base *);
+
+/**
+ * @name event flags
+ *
+ * Flags to pass to event_new(), event_assign(), event_pending(), and
+ * anything else with an argument of the form "short events"
+ */
+/**@{*/
+/** Indicates that a timeout has occurred.  It's not necessary to pass
+ * this flag to event_for new()/event_assign() to get a timeout. */
+#define EV_TIMEOUT	0x01
+/** Wait for a socket or FD to become readable */
+#define EV_READ		0x02
+/** Wait for a socket or FD to become writeable */
+#define EV_WRITE	0x04
+/** Wait for a POSIX signal to be raised*/
+#define EV_SIGNAL	0x08
+/**
+ * Persistent event: won't get removed automatically when activated.
+ *
+ * When a persistent event with a timeout becomes activated, its timeout
+ * is reset to 0.
+ */
+#define EV_PERSIST	0x10
+/** Select edge-triggered behavior, if supported by the backend. */
+#define EV_ET		0x20
+/**
+ * If this option is provided, then event_del() will not block in one thread
+ * while waiting for the event callback to complete in another thread.
+ *
+ * To use this option safely, you may need to use event_finalize() or
+ * event_free_finalize() in order to safely tear down an event in a
+ * multithreaded application.  See those functions for more information.
+ **/
+#define EV_FINALIZE     0x40
+/**
+ * Detects connection close events.  You can use this to detect when a
+ * connection has been closed, without having to read all the pending data
+ * from a connection.
+ *
+ * Not all backends support EV_CLOSED.  To detect or require it, use the
+ * feature flag EV_FEATURE_EARLY_CLOSE.
+ **/
+#define EV_CLOSED	0x80
+/**@}*/
+
+/**
+   @name evtimer_* macros
+
+   Aliases for working with one-shot timer events
+   If you need EV_PERSIST timer use event_*() functions.
+ */
+/**@{*/
+#define evtimer_assign(ev, b, cb, arg) \
+	event_assign((ev), (b), -1, 0, (cb), (arg))
+#define evtimer_new(b, cb, arg)		event_new((b), -1, 0, (cb), (arg))
+#define evtimer_add(ev, tv)		event_add((ev), (tv))
+#define evtimer_del(ev)			event_del(ev)
+#define evtimer_pending(ev, tv)		event_pending((ev), EV_TIMEOUT, (tv))
+#define evtimer_initialized(ev)		event_initialized(ev)
+/**@}*/
+
+/**
+   @name evsignal_* macros
+
+   Aliases for working with signal events
+ */
+/**@{*/
+#define evsignal_add(ev, tv)		event_add((ev), (tv))
+#define evsignal_assign(ev, b, x, cb, arg)			\
+	event_assign((ev), (b), (x), EV_SIGNAL|EV_PERSIST, cb, (arg))
+#define evsignal_new(b, x, cb, arg)				\
+	event_new((b), (x), EV_SIGNAL|EV_PERSIST, (cb), (arg))
+#define evsignal_del(ev)		event_del(ev)
+#define evsignal_pending(ev, tv)	event_pending((ev), EV_SIGNAL, (tv))
+#define evsignal_initialized(ev)	event_initialized(ev)
+/**@}*/
+
+/**
+   @name evuser_* macros
+
+   Aliases for working with user-triggered events
+   If you need EV_PERSIST event use event_*() functions.
+ */
+/**@{*/
+#define evuser_new(b, cb, arg)		event_new((b), -1, 0, (cb), (arg))
+#define evuser_del(ev)			event_del(ev)
+#define evuser_pending(ev, tv)		event_pending((ev), 0, (tv))
+#define evuser_initialized(ev)		event_initialized(ev)
+#define evuser_trigger(ev)		event_active((ev), 0, 0)
+/**@}*/
+
+/**
+   A callback function for an event.
+
+   It receives three arguments:
+
+   @param fd An fd or signal
+   @param events One or more EV_* flags
+   @param arg A user-supplied argument.
+
+   @see event_new()
+ */
+typedef void (*event_callback_fn)(evutil_socket_t, short, void *);
+
+/**
+  Return a value used to specify that the event itself must be used as the callback argument.
+
+  The function event_new() takes a callback argument which is passed
+  to the event's callback function. To specify that the argument to be
+  passed to the callback function is the event that event_new() returns,
+  pass in the return value of event_self_cbarg() as the callback argument
+  for event_new().
+
+  For example:
+  <pre>
+      struct event *ev = event_new(base, sock, events, callback, %event_self_cbarg());
+  </pre>
+
+  For consistency with event_new(), it is possible to pass the return value
+  of this function as the callback argument for event_assign() &ndash; this
+  achieves the same result as passing the event in directly.
+
+  @return a value to be passed as the callback argument to event_new() or
+  event_assign().
+  @see event_new(), event_assign()
+ */
+EVENT2_EXPORT_SYMBOL
+void *event_self_cbarg(void);
+
+/**
+  Allocate and assign a new event structure, ready to be added.
+
+  The function event_new() returns a new event that can be used in
+  future calls to event_add() and event_del().  The fd and events
+  arguments determine which conditions will trigger the event; the
+  callback and callback_arg arguments tell Libevent what to do when the
+  event becomes active.
+
+  If events contains one of EV_READ, EV_WRITE, or EV_READ|EV_WRITE, then
+  fd is a file descriptor or socket that should get monitored for
+  readiness to read, readiness to write, or readiness for either operation
+  (respectively).  If events contains EV_SIGNAL, then fd is a signal
+  number to wait for.  If events contains none of those flags, then the
+  event can be triggered only by a timeout or by manual activation with
+  event_active(): In this case, fd must be -1.
+
+  The EV_PERSIST flag can also be passed in the events argument: it makes
+  event_add() persistent until event_del() is called.
+
+  The EV_ET flag is compatible with EV_READ and EV_WRITE, and supported
+  only by certain backends.  It tells Libevent to use edge-triggered
+  events.
+
+  The EV_TIMEOUT flag has no effect here.
+
+  It is okay to have multiple events all listening on the same fds; but
+  they must either all be edge-triggered, or all not be edge triggered.
+
+  When the event becomes active, the event loop will run the provided
+  callback function, with three arguments.  The first will be the provided
+  fd value.  The second will be a bitfield of the events that triggered:
+  EV_READ, EV_WRITE, or EV_SIGNAL.  Here the EV_TIMEOUT flag indicates
+  that a timeout occurred, and EV_ET indicates that an edge-triggered
+  event occurred.  The third event will be the callback_arg pointer that
+  you provide.
+
+  @param base the event base to which the event should be attached.
+  @param fd the file descriptor or signal to be monitored, or -1.
+  @param events desired events to monitor: bitfield of EV_READ, EV_WRITE,
+      EV_SIGNAL, EV_PERSIST, EV_ET.
+  @param callback callback function to be invoked when the event occurs
+  @param callback_arg an argument to be passed to the callback function
+
+  @return a newly allocated struct event that must later be freed with
+    event_free() or NULL if an error occurred.
+  @see event_free(), event_add(), event_del(), event_assign()
+ */
+EVENT2_EXPORT_SYMBOL
+struct event *event_new(struct event_base *, evutil_socket_t, short, event_callback_fn, void *);
+
+
+/**
+  Prepare a new, already-allocated event structure to be added.
+
+  The function event_assign() prepares the event structure ev to be used
+  in future calls to event_add() and event_del().  Unlike event_new(), it
+  doesn't allocate memory itself: it requires that you have already
+  allocated a struct event, probably on the heap.  Doing this will
+  typically make your code depend on the size of the event structure, and
+  thereby create incompatibility with future versions of Libevent.
+
+  The easiest way to avoid this problem is just to use event_new() and
+  event_free() instead.
+
+  A slightly harder way to future-proof your code is to use
+  event_get_struct_event_size() to determine the required size of an event
+  at runtime.
+
+  Note that it is NOT safe to call this function on an event that is
+  active or pending.  Doing so WILL corrupt internal data structures in
+  Libevent, and lead to strange, hard-to-diagnose bugs.  You _can_ use
+  event_assign to change an existing event, but only if it is not active
+  or pending!
+
+  The arguments for this function, and the behavior of the events that it
+  makes, are as for event_new().
+
+  @param ev an event struct to be modified
+  @param base the event base to which ev should be attached.
+  @param fd the file descriptor to be monitored
+  @param events desired events to monitor; can be EV_READ and/or EV_WRITE
+  @param callback callback function to be invoked when the event occurs
+  @param callback_arg an argument to be passed to the callback function
+
+  @return 0 if success, or -1 on invalid arguments.
+
+  @see event_new(), event_add(), event_del(), event_base_once(),
+    event_get_struct_event_size()
+  */
+EVENT2_EXPORT_SYMBOL
+int event_assign(struct event *, struct event_base *, evutil_socket_t, short, event_callback_fn, void *);
+
+/**
+   Deallocate a struct event * returned by event_new().
+
+   If the event is pending or active, this function makes it non-pending
+   and non-active first.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_free(struct event *);
+
+/**
+ * Callback type for event_finalize and event_free_finalize().
+ **/
+typedef void (*event_finalize_callback_fn)(struct event *, void *);
+/**
+   @name Finalization functions
+
+   These functions are used to safely tear down an event in a multithreaded
+   application.  If you construct your events with EV_FINALIZE to avoid
+   deadlocks, you will need a way to remove an event in the certainty that
+   it will definitely not be running its callback when you deallocate it
+   and its callback argument.
+
+   To do this, call one of event_finalize() or event_free_finalize with
+   0 for its first argument, the event to tear down as its second argument,
+   and a callback function as its third argument.  The callback will be
+   invoked as part of the event loop, with the event's priority.
+
+   After you call a finalizer function, event_add() and event_active() will
+   no longer work on the event, and event_del() will produce a no-op. You
+   must not try to change the event's fields with event_assign() or
+   event_set() while the finalize callback is in progress.  Once the
+   callback has been invoked, you should treat the event structure as
+   containing uninitialized memory.
+
+   The event_free_finalize() function frees the event after it's finalized;
+   event_finalize() does not.
+
+   A finalizer callback must not make events pending or active.  It must not
+   add events, activate events, or attempt to "resuscitate" the event being
+   finalized in any way.
+
+   @return 0 on success, -1 on failure.
+ */
+/**@{*/
+EVENT2_EXPORT_SYMBOL
+int event_finalize(unsigned, struct event *, event_finalize_callback_fn);
+EVENT2_EXPORT_SYMBOL
+int event_free_finalize(unsigned, struct event *, event_finalize_callback_fn);
+/**@}*/
+
+/**
+  Schedule a one-time event
+
+  The function event_base_once() is similar to event_new().  However, it
+  schedules a callback to be called exactly once, and does not require the
+  caller to prepare an event structure.
+
+  Note that in Libevent 2.0 and earlier, if the event is never triggered, the
+  internal memory used to hold it will never be freed.  In Libevent 2.1,
+  the internal memory will get freed by event_base_free() if the event
+  is never triggered.  The 'arg' value, however, will not get freed in either
+  case--you'll need to free that on your own if you want it to go away.
+
+  @param base an event_base
+  @param fd a file descriptor to monitor, or -1 for no fd.
+  @param events event(s) to monitor; can be any of EV_READ |
+         EV_WRITE, or EV_TIMEOUT
+  @param callback callback function to be invoked when the event occurs
+  @param arg an argument to be passed to the callback function
+  @param timeout the maximum amount of time to wait for the event. NULL
+         makes an EV_READ/EV_WRITE event make forever; NULL makes an
+        EV_TIMEOUT event success immediately.
+  @return 0 if successful, or -1 if an error occurred
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_once(struct event_base *, evutil_socket_t, short, event_callback_fn, void *, const struct timeval *);
+
+/**
+  Add an event to the set of pending events.
+
+  The function event_add() schedules the execution of the event 'ev' when the
+  condition specified by event_assign() or event_new() occurs, or when the time
+  specified in timeout has elapsed.  If a timeout is NULL, no timeout
+  occurs and the function will only be
+  called if a matching event occurs.  The event in the
+  ev argument must be already initialized by event_assign() or event_new()
+  and may not be used
+  in calls to event_assign() until it is no longer pending.
+
+  If the event in the ev argument already has a scheduled timeout, calling
+  event_add() replaces the old timeout with the new one if tv is non-NULL.
+
+  @param ev an event struct initialized via event_assign() or event_new()
+  @param timeout the maximum amount of time to wait for the event, or NULL
+         to wait forever
+  @return 0 if successful, or -1 if an error occurred
+  @see event_del(), event_assign(), event_new()
+  */
+EVENT2_EXPORT_SYMBOL
+int event_add(struct event *ev, const struct timeval *timeout);
+
+/**
+   Remove a timer from a pending event without removing the event itself.
+
+   If the event has a scheduled timeout, this function unschedules it but
+   leaves the event otherwise pending.
+
+   @param ev an event struct initialized via event_assign() or event_new()
+   @return 0 on success, or -1 if an error occurred.
+*/
+EVENT2_EXPORT_SYMBOL
+int event_remove_timer(struct event *ev);
+
+/**
+  Remove an event from the set of monitored events.
+
+  The function event_del() will cancel the event in the argument ev.  If the
+  event has already executed or has never been added the call will have no
+  effect.
+
+  @param ev an event struct to be removed from the working set
+  @return 0 if successful, or -1 if an error occurred
+  @see event_add()
+ */
+EVENT2_EXPORT_SYMBOL
+int event_del(struct event *);
+
+/**
+   As event_del(), but never blocks while the event's callback is running
+   in another thread, even if the event was constructed without the
+   EV_FINALIZE flag.
+ */
+EVENT2_EXPORT_SYMBOL
+int event_del_noblock(struct event *ev);
+/**
+   As event_del(), but always blocks while the event's callback is running
+   in another thread, even if the event was constructed with the
+   EV_FINALIZE flag.
+ */
+EVENT2_EXPORT_SYMBOL
+int event_del_block(struct event *ev);
+
+/**
+  Make an event active.
+
+  You can use this function on a pending or a non-pending event to make it
+  active, so that its callback will be run by event_base_dispatch() or
+  event_base_loop().
+
+  One common use in multithreaded programs is to wake the thread running
+  event_base_loop() from another thread.
+
+  @param ev an event to make active.
+  @param res a set of flags to pass to the event's callback.
+  @param ncalls an obsolete argument: this is ignored.
+ **/
+EVENT2_EXPORT_SYMBOL
+void event_active(struct event *ev, int res, short ncalls);
+
+/**
+  Checks if a specific event is pending or scheduled.
+
+  @param ev an event struct previously passed to event_add()
+  @param events the requested event type; any of EV_TIMEOUT|EV_READ|
+         EV_WRITE|EV_SIGNAL
+  @param tv if this field is not NULL, and the event has a timeout,
+         this field is set to hold the time at which the timeout will
+	 expire.
+
+  @return true if the event is pending on any of the events in 'what', (that
+  is to say, it has been added), or 0 if the event is not added.
+ */
+EVENT2_EXPORT_SYMBOL
+int event_pending(const struct event *ev, short events, struct timeval *tv);
+
+/**
+   If called from within the callback for an event, returns that event.
+
+   The behavior of this function is not defined when called from outside the
+   callback function for an event.
+ */
+EVENT2_EXPORT_SYMBOL
+struct event *event_base_get_running_event(struct event_base *base);
+
+/**
+  Test if an event structure might be initialized.
+
+  The event_initialized() function can be used to check if an event has been
+  initialized.
+
+  Warning: This function is only useful for distinguishing a zeroed-out
+    piece of memory from an initialized event, it can easily be confused by
+    uninitialized memory.  Thus, it should ONLY be used to distinguish an
+    initialized event from zero.
+
+  @param ev an event structure to be tested
+  @return 1 if the structure might be initialized, or 0 if it has not been
+          initialized
+ */
+EVENT2_EXPORT_SYMBOL
+int event_initialized(const struct event *ev);
+
+/**
+   Get the signal number assigned to a signal event
+*/
+#define event_get_signal(ev) ((int)event_get_fd(ev))
+
+/**
+   Get the socket or signal assigned to an event, or -1 if the event has
+   no socket.
+*/
+EVENT2_EXPORT_SYMBOL
+evutil_socket_t event_get_fd(const struct event *ev);
+
+/**
+   Get the event_base associated with an event.
+*/
+EVENT2_EXPORT_SYMBOL
+struct event_base *event_get_base(const struct event *ev);
+
+/**
+   Return the events (EV_READ, EV_WRITE, etc) assigned to an event.
+*/
+EVENT2_EXPORT_SYMBOL
+short event_get_events(const struct event *ev);
+
+/**
+   Return the callback assigned to an event.
+*/
+EVENT2_EXPORT_SYMBOL
+event_callback_fn event_get_callback(const struct event *ev);
+
+/**
+   Return the callback argument assigned to an event.
+*/
+EVENT2_EXPORT_SYMBOL
+void *event_get_callback_arg(const struct event *ev);
+
+/**
+   Return the priority of an event.
+   @see event_priority_init(), event_get_priority()
+*/
+EVENT2_EXPORT_SYMBOL
+int event_get_priority(const struct event *ev);
+
+/**
+   Extract _all_ of arguments given to construct a given event.  The
+   event_base is copied into *base_out, the fd is copied into *fd_out, and so
+   on.
+
+   If any of the "_out" arguments is NULL, it will be ignored.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_get_assignment(const struct event *event,
+    struct event_base **base_out, evutil_socket_t *fd_out, short *events_out,
+    event_callback_fn *callback_out, void **arg_out);
+
+/**
+   Return the size of struct event that the Libevent library was compiled
+   with.
+
+   This will be NO GREATER than sizeof(struct event) if you're running with
+   the same version of Libevent that your application was built with, but
+   otherwise might not.
+
+   Note that it might be SMALLER than sizeof(struct event) if some future
+   version of Libevent adds extra padding to the end of struct event.
+   We might do this to help ensure ABI-compatibility between different
+   versions of Libevent.
+ */
+EVENT2_EXPORT_SYMBOL
+size_t event_get_struct_event_size(void);
+
+/**
+   Get the Libevent version.
+
+   Note that this will give you the version of the library that you're
+   currently linked against, not the version of the headers that you've
+   compiled against.
+
+   @return a string containing the version number of Libevent
+*/
+EVENT2_EXPORT_SYMBOL
+const char *event_get_version(void);
+
+/**
+   Return a numeric representation of Libevent's version.
+
+   Note that this will give you the version of the library that you're
+   currently linked against, not the version of the headers you've used to
+   compile.
+
+   The format uses one byte each for the major, minor, and patchlevel parts of
+   the version number.  The low-order byte is unused.  For example, version
+   2.0.1-alpha has a numeric representation of 0x02000100
+*/
+EVENT2_EXPORT_SYMBOL
+ev_uint32_t event_get_version_number(void);
+
+/** As event_get_version, but gives the version of Libevent's headers. */
+#define LIBEVENT_VERSION EVENT__VERSION
+/** As event_get_version_number, but gives the version number of Libevent's
+ * headers. */
+#define LIBEVENT_VERSION_NUMBER EVENT__NUMERIC_VERSION
+
+/** Largest number of priorities that Libevent can support. */
+#define EVENT_MAX_PRIORITIES 256
+/**
+  Set the number of different event priorities
+
+  By default Libevent schedules all active events with the same priority.
+  However, some time it is desirable to process some events with a higher
+  priority than others.  For that reason, Libevent supports strict priority
+  queues.  Active events with a lower priority are always processed before
+  events with a higher priority.
+
+  The number of different priorities can be set initially with the
+  event_base_priority_init() function.  This function should be called
+  before the first call to event_base_dispatch().  The
+  event_priority_set() function can be used to assign a priority to an
+  event.  By default, Libevent assigns the middle priority to all events
+  unless their priority is explicitly set.
+
+  Note that urgent-priority events can starve less-urgent events: after
+  running all urgent-priority callbacks, Libevent checks for more urgent
+  events again, before running less-urgent events.  Less-urgent events
+  will not have their callbacks run until there are no events more urgent
+  than them that want to be active.
+
+  @param eb the event_base structure returned by event_base_new()
+  @param npriorities the maximum number of priorities
+  @return 0 if successful, or -1 if an error occurred
+  @see event_priority_set()
+ */
+EVENT2_EXPORT_SYMBOL
+int	event_base_priority_init(struct event_base *, int);
+
+/**
+  Get the number of different event priorities.
+
+  @param eb the event_base structure returned by event_base_new()
+  @return Number of different event priorities
+  @see event_base_priority_init()
+*/
+EVENT2_EXPORT_SYMBOL
+int	event_base_get_npriorities(struct event_base *eb);
+
+/**
+  Assign a priority to an event.
+
+  @param ev an event struct
+  @param priority the new priority to be assigned
+  @return 0 if successful, or -1 if an error occurred
+  @see event_priority_init(), event_get_priority()
+  */
+EVENT2_EXPORT_SYMBOL
+int	event_priority_set(struct event *, int);
+
+/**
+   Prepare an event_base to use a large number of timeouts with the same
+   duration.
+
+   Libevent's default scheduling algorithm is optimized for having a large
+   number of timeouts with their durations more or less randomly
+   distributed.  But if you have a large number of timeouts that all have
+   the same duration (for example, if you have a large number of
+   connections that all have a 10-second timeout), then you can improve
+   Libevent's performance by telling Libevent about it.
+
+   To do this, call this function with the common duration.  It will return a
+   pointer to a different, opaque timeout value.  (Don't depend on its actual
+   contents!)  When you use this timeout value in event_add(), Libevent will
+   schedule the event more efficiently.
+
+   (This optimization probably will not be worthwhile until you have thousands
+   or tens of thousands of events with the same timeout.)
+ */
+EVENT2_EXPORT_SYMBOL
+const struct timeval *event_base_init_common_timeout(struct event_base *base,
+    const struct timeval *duration);
+
+#if !defined(EVENT__DISABLE_MM_REPLACEMENT) || defined(EVENT_IN_DOXYGEN_)
+/**
+ Override the functions that Libevent uses for memory management.
+
+ Usually, Libevent uses the standard libc functions malloc, realloc, and
+ free to allocate memory.  Passing replacements for those functions to
+ event_set_mem_functions() overrides this behavior.
+
+ Note that all memory returned from Libevent will be allocated by the
+ replacement functions rather than by malloc() and realloc().  Thus, if you
+ have replaced those functions, it will not be appropriate to free() memory
+ that you get from Libevent.  Instead, you must use the free_fn replacement
+ that you provided.
+
+ Note also that if you are going to call this function, you should do so
+ before any call to any Libevent function that does allocation.
+ Otherwise, those functions will allocate their memory using malloc(), but
+ then later free it using your provided free_fn.
+
+ @param malloc_fn A replacement for malloc.
+ @param realloc_fn A replacement for realloc
+ @param free_fn A replacement for free.
+ **/
+EVENT2_EXPORT_SYMBOL
+void event_set_mem_functions(
+	void *(*malloc_fn)(size_t sz),
+	void *(*realloc_fn)(void *ptr, size_t sz),
+	void (*free_fn)(void *ptr));
+/** This definition is present if Libevent was built with support for
+    event_set_mem_functions() */
+#define EVENT_SET_MEM_FUNCTIONS_IMPLEMENTED
+#endif
+
+/**
+   Writes a human-readable description of all inserted and/or active
+   events to a provided stdio stream.
+
+   This is intended for debugging; its format is not guaranteed to be the same
+   between libevent versions.
+
+   @param base An event_base on which to scan the events.
+   @param output A stdio file to write on.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_base_dump_events(struct event_base *, FILE *);
+
+
+/**
+   Activates all pending events for the given fd and event mask.
+
+   This function activates pending events only.  Events which have not been
+   added will not become active.
+
+   @param base the event_base on which to activate the events.
+   @param fd An fd to active events on.
+   @param events One or more of EV_{READ,WRITE,TIMEOUT}.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_base_active_by_fd(struct event_base *base, evutil_socket_t fd, short events);
+
+/**
+   Activates all pending signals with a given signal number
+
+   This function activates pending events only.  Events which have not been
+   added will not become active.
+
+   @param base the event_base on which to activate the events.
+   @param fd The signal to active events on.
+ */
+EVENT2_EXPORT_SYMBOL
+void event_base_active_by_signal(struct event_base *base, int sig);
+
+/**
+ * Callback for iterating events in an event base via event_base_foreach_event
+ */
+typedef int (*event_base_foreach_event_cb)(const struct event_base *, const struct event *, void *);
+
+/**
+   Iterate over all added or active events events in an event loop, and invoke
+   a given callback on each one.
+
+   The callback must not call any function that modifies the event base, that
+   modifies any event in the event base, or that adds or removes any event to
+   the event base.  Doing so is unsupported and will lead to undefined
+   behavior -- likely, to crashes.
+
+   event_base_foreach_event() holds a lock on the event_base() for the whole
+   time it's running: slow callbacks are not advisable.
+
+   Note that Libevent adds some events of its own to make pieces of its
+   functionality work.  You must not assume that the only events you'll
+   encounter will be the ones you added yourself.
+
+   The callback function must return 0 to continue iteration, or some other
+   integer to stop iterating.
+
+   @param base An event_base on which to scan the events.
+   @param fn   A callback function to receive the events.
+   @param arg  An argument passed to the callback function.
+   @return 0 if we iterated over every event, or the value returned by the
+      callback function if the loop exited early.
+*/
+EVENT2_EXPORT_SYMBOL
+int event_base_foreach_event(struct event_base *base, event_base_foreach_event_cb fn, void *arg);
+
+
+/** Sets 'tv' to the current time (as returned by gettimeofday()),
+    looking at the cached value in 'base' if possible, and calling
+    gettimeofday() or clock_gettime() as appropriate if there is no
+    cached time.
+
+    Generally, this value will only be cached while actually
+    processing event callbacks, and may be very inaccurate if your
+    callbacks take a long time to execute.
+
+    Returns 0 on success, negative on failure.
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_gettimeofday_cached(struct event_base *base,
+    struct timeval *tv);
+
+/** Update cached_tv in the 'base' to the current time
+ *
+ * You can use this function is useful for selectively increasing
+ * the accuracy of the cached time value in 'base' during callbacks
+ * that take a long time to execute.
+ *
+ * This function has no effect if the base is currently not in its
+ * event loop, or if timeval caching is disabled via
+ * EVENT_BASE_FLAG_NO_CACHE_TIME.
+ *
+ * @return 0 on success, -1 on failure
+ */
+EVENT2_EXPORT_SYMBOL
+int event_base_update_cache_time(struct event_base *base);
+
+/** Release up all globally-allocated resources allocated by Libevent.
+
+    This function does not free developer-controlled resources like
+    event_bases, events, bufferevents, listeners, and so on.  It only releases
+    resources like global locks that there is no other way to free.
+
+    It is not actually necessary to call this function before exit: every
+    resource that it frees would be released anyway on exit.  It mainly exists
+    so that resource-leak debugging tools don't see Libevent as holding
+    resources at exit.
+
+    You should only call this function when no other Libevent functions will
+    be invoked -- e.g., when cleanly exiting a program.
+ */
+EVENT2_EXPORT_SYMBOL
+void libevent_global_shutdown(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* EVENT2_EVENT_H_INCLUDED_ */