struct event_base *
event_init(
)
int
event_dispatch(
)
int
event_loop(
int flags
)
int
event_loopexit(
struct timeval *tv
)
int
event_loopbreak(
void
)
int
event_base_dispatch(
struct event_base *base
)
void
event_base_free(
struct event_base *base
)
int
event_base_loop(
struct event_base *base
, int flags
)
int
event_base_loopexit(
struct event_base *base
, struct timeval *tv
)
int
event_base_loopbreak(
struct event_base *base
)
int
event_base_set(
struct event_base *base
, struct event *
)
void
event_set(
struct event *ev
, int fd
, short event
void (*fn)(int, short, void *), void *arg
)
int
event_add(
struct event *ev
, struct timeval *tv
)
int
event_del(
struct event *ev
)
int
event_once(
int fd
, short event
void (*fn)(int, short, void *), void *arg
, struct timeval *tv
)
inr
event_base_once(
struct event_base *base
, int fd
, short event
void (*fn)(int, short, void *), void *arg
, struct timeval *tv
)
int
event_pending(
struct event *ev
, short event
, struct timeval *tv
)
int
event_initialized(
struct event *ev
)
void
evtimer_set(
struct event *ev
void (*fn)(int, short, void *), void *arg
)
void
evtimer_add(
struct event *ev
, struct timeval *tv
)
void
evtimer_del(
struct event *ev
)
int
evtimer_pending(
struct event *ev
, struct timeval *tv
)
int
evtimer_initialized(
struct event *ev
)
void
signal_set(
struct event *ev
, int signal
void (*fn)(int, short, void *), void *arg
)
void
signal_add(
struct event *ev
, struct timeval *tv
)
void
signal_del(
struct event *ev
)
int
signal_pending(
struct event *ev
, struct timeval *tv
)
int
signal_initialized(
struct event *ev
)
struct bufferevent *
bufferevent_new(
int fd
, evbuffercb readcb
, evbuffercb writecb
, everrorcb
, void *cbarg
)
void
bufferevent_free(
struct bufferevent *bufev
)
int
bufferevent_write(
struct bufferevent *bufev
, void *data
, size_t size
)
int
bufferevent_write_buffer(
struct bufferevent *bufev
, struct evbuffer *buf
)
size_t
bufferevent_read(
struct bufferevent *bufev
, void *data
, size_t size
)
int
bufferevent_enable(
struct bufferevent *bufev
, short event
)
int
bufferevent_disable(
struct bufferevent *bufev
, short event
)
void
bufferevent_settimeout(
struct bufferevent *bufev
, int timeout_read
, int timeout_write
)
int
bufferevent_base_set(
struct event_base *base
, struct bufferevent *bufev
)
struct evbuffer *
evbuffer_new(
void
)
void
evbuffer_free(
struct evbuffer *buf
)
int
evbuffer_add(
struct evbuffer *buf
, const void *data
, size_t size
)
int
evbuffer_add_buffer(
struct evbuffer *dst
, struct evbuffer *src
)
int
evbuffer_add_printf(
struct evbuffer *buf
, const char *fmt
, ...
)
int
evbuffer_add_vprintf(
struct evbuffer *buf
, const char *fmt
, va_list ap
)
void
evbuffer_drain(
struct evbuffer *buf
, size_t size
)
int
evbuffer_write(
struct evbuffer *buf
, int fd
)
int
evbuffer_read(
struct evbuffer *buf
, int fd
, int size
)
u_char *
evbuffer_find(
struct evbuffer *buf
, const u_char *data
, size_t size
)
char *
evbuffer_readline(
struct evbuffer *buf
)
struct evhttp *
evhttp_new(
struct event_base *base
)
int
evhttp_bind_socket(
struct evhttp *http
, const char *address
, u_short port
)
void
evhttp_free(
struct evhttp *http
)
int
(*event_sigcb)(void)
;
volatile
sig_atomic_t
event_gotsig
;
The
event
API needs to be initialized with
event_init()
before it can be used.
In order to process events, an application needs to call
event_dispatch().
This function only returns on error, and should replace the event core
of the application program.
The function
event_set()
prepares the event structure
ev
to be used in future calls to
event_add()
and
event_del(
).
The event will be prepared to call the function specified by the
fn
argument with an
int
argument indicating the file descriptor, a
short
argument indicating the type of event, and a
void
*
argument given in the
arg
argument.
The
fd
indicates the file descriptor that should be monitored for events.
The events can be either
EV_READ,
EV_WRITE,
or both,
indicating that an application can read or write from the file descriptor
respectively without blocking.
The function
fn
will be called with the file descriptor that triggered the event and
the type of event which will be either
EV_TIMEOUT,
EV_SIGNAL,
EV_READ,
or
EV_WRITE.
Additionally, an event which has registered interest in more than one of the
preceeding events, via bitwise-OR to
event_set(),
can provide its callback function with a bitwise-OR of more than one triggered
event.
The additional flag
EV_PERSIST
makes an
event_add(
)
persistent until
event_del(
)
has been called.
Once initialized, the
ev
structure can be used repeatedly with
event_add()
and
event_del(
)
and does not need to be reinitialized unless the function called and/or
the argument to it are to be changed.
However, when an
ev
structure has been added to libevent using
event_add()
the structure must persist until the event occurs (assuming
EV_PERSIST
is not set) or is removed
using
event_del().
You may not reuse the same
ev
structure for multiple monitored descriptors; each descriptor
needs its own
ev
.
The function
event_add()
schedules the execution of the
ev
event when the event specified in
event_set()
occurs or in at least the time specified in the
tv
.
If
tv
is
NULL
,
no timeout occurs and the function will only be called
if a matching event occurs on the file descriptor.
The event in the
ev
argument must be already initialized by
event_set()
and may not be used in calls to
event_set(
)
until it has timed out or been removed with
event_del(
).
If the event in the
ev
argument already has a scheduled timeout, the old timeout will be
replaced by the new one.
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.
The functions
evtimer_set(),
evtimer_add(
),
evtimer_del(
),
evtimer_initialized(
),
and
evtimer_pending(
)
are abbreviations for common situations where only a timeout is required.
The file descriptor passed will be -1, and the event type will be
EV_TIMEOUT.
The functions
signal_set(),
signal_add(
),
signal_del(
),
signal_initialized(
),
and
signal_pending(
)
are abbreviations.
The event type will be a persistent
EV_SIGNAL.
That means
signal_set(
)
adds
EV_PERSIST.
In order to avoid races in signal handlers, the
event
API provides two variables:
event_sigcb
and
event_gotsig.
A signal handler
sets
event_gotsig
to indicate that a signal has been received.
The application sets
event_sigcb
to a callback function.
After the signal handler sets
event_gotsig,
event_dispatch
will execute the callback function to process received signals.
The callback returns 1 when no events are registered any more.
It can return -1 to indicate an error to the
event
library, causing
event_dispatch()
to terminate with
errno
set to
EINTR
.
The function
event_once()
is similar to
event_set(
).
However, it schedules a callback to be called exactly once and does not
require the caller to prepare an
event
structure.
This function supports
EV_TIMEOUT
,
EV_READ
,
and
EV_WRITE
.
The
event_pending()
function can be used to check if the event specified by
event
is pending to run.
If
EV_TIMEOUT
was specified and
tv
is not
NULL
,
the expiration time of the event will be returned in
tv
.
The
event_initialized()
macro can be used to check if an event has been initialized.
The
event_loop
function provides an interface for single pass execution of pending
events.
The flags
EVLOOP_ONCE
and
EVLOOP_NONBLOCK
are recognized.
The
event_loopexit
function exits from the event loop. The next
event_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_loop(
)
will proceed normally.
The
event_loopbreak
function exits from the event loop immediately.
event_loop(
)
will abort after the next event is completed;
event_loopbreak(
)
is typically invoked from this event's callback. This behavior is analogous
to the "break;" statement. Subsequent invocations of
event_loop(
)
will proceed normally.
It is the responsibility of the caller to provide these functions with pre-allocated event structures.
The number of different priorities can be set initially with the
event_priority_init()
function.
This function should be called before the first call to
event_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.
),
an event base is returned.
This event base can be used in conjunction with calls to
event_base_set(
),
event_base_dispatch(
),
event_base_loop(
),
event_base_loopexit(
),
bufferevent_base_set(
)
and
event_base_free(
).
event_base_set(
)
should be called after preparing an event with
event_set(
),
as
event_set(
)
assigns the provided event to the most recently created event base.
bufferevent_base_set(
)
should be called after preparing a bufferevent with
bufferevent_new(
).
event_base_free(
)
should be used to free memory associated with the event base
when it is no longer needed.
A new bufferevent is created by
bufferevent_new().
The parameter
fd
specifies the file descriptor from which data is read and written to.
This file descriptor is not allowed to be a
pipe(2).
The next three parameters are callbacks.
The read and write callback have the following form:
void
(*cb)(struct bufferevent *bufev
, void *arg
).
The error callback has the following form:
void
(*cb)(struct bufferevent *bufev
, short what
, void *arg
).
The argument is specified by the fourth parameter
cbarg
.
A
bufferevent
struct
pointer is returned on success, NULL on error.
Both the read and the write callback may be NULL.
The error callback has to be always provided.
Once initialized, the bufferevent structure can be used repeatedly with
bufferevent_enable()
and
bufferevent_disable(
).
The flags parameter can be a combination of
EV_READ
and
EV_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.
The
bufferevent_write()
function can be used to write data to the file descriptor.
The data is appended to the output buffer and written to the descriptor
automatically as it becomes available for writing.
bufferevent_write(
)
returns 0 on success or -1 on failure.
The
bufferevent_read(
)
function is used to read data from the input buffer,
returning the amount of data read.
If multiple bases are in use,
bufferevent_base_set()
must be called before enabling the bufferevent for the first time.
).
It can be bound to any port and address with the
evhttp_bind_socket(
)
function.
When the HTTP server is no longer used, it can be freed via
evhttp_free(
).
To be notified of HTTP requests, a user needs to register callbacks with the
HTTP server.
This can be done by calling
evhttp_set_cb().
The second argument is the URI for which a callback is being registered.
The corresponding callback will receive an
struct evhttp_request
object that contains all information about the request.
This section does not document all the possible function calls; please check event.h for the public interfaces.
)
and
event_del(
)
return 0.
Otherwise, -1 is returned and the global variable errno is
set to indicate the error.