iv_event_raw(3) ivykis programmer's manual iv_event_raw(3)NAME
IV_EVENT_RAW_INIT, iv_event_raw_register, iv_event_raw_unregister,
iv_event_raw_post - manage ivykis objects for event notification
SYNOPSIS
#include <iv_event_raw.h>
struct iv_event_raw {
void *cookie;
void (*handler)(void *);
};
void IV_EVENT_RAW_INIT(struct iv_event_raw *this);
int iv_event_raw_register(struct iv_event_raw *this);
void iv_event_raw_unregister(struct iv_event_raw *this);
void iv_event_raw_post(const struct iv_event_raw *this);
DESCRIPTION
iv_event_raw provides a way for delivering events to ivykis(3) recipi‐
ents across thread and process boundaries.
The intended event recipient calls IV_EVENT_RAW_INIT on a struct
iv_event_raw object, fills in ->cookie and ->handler, and then calls
iv_event_raw_register on the object.
To generate an event, call iv_event_raw_post on the previously initial‐
ized struct iv_event_raw object. This will cause the callback speci‐
fied by ->handler to be called in the thread that the struct
iv_event_raw object was registered in, with ->cookie as its sole argu‐
ment.
To deinitialize a struct iv_event_raw object, call iv_event_raw_unreg‐
ister from the same thread that iv_event_raw_register was called from
on that object.
It is permitted to unregister a struct iv_event_raw object from any
ivykis callback function in the thread it was registered in, including
from a callback function triggered by this object, and it is permitted
to free the memory corresponding to an unregistered object from its own
callback function.
iv_event_raw_post can be called from the same thread that
iv_event_raw_register was called from, from a different thread in the
same process, or even from a different process, and can safely be
called from signal handlers.
If posting an event only ever needs to be done from within the same
process, see iv_event(3) for a lighter-weight alternative to
iv_event_raw.
Internally, iv_event_raw is implemented by registering a file descrip‐
tor (a struct iv_fd(3)) with the recipient thread's ivykis event loop,
and by causing that file descriptor to become readable upon a call to
iv_event_raw_post.
If eventfd(2) is available, it will be used to procure the abovemen‐
tioned file descriptor. If not, iv_event_raw will fall back to pipe(2)
as the source of its file descriptors. eventfd(2) is preferred as it
requires only one file descriptor table entry (while pipe(2) requires
two), and has much less kernel overhead than pipe(2) has.
SEE ALSOivykis(3), iv_event(3), eventfd(2), pipe(2)ivykis 2010-09-02 iv_event_raw(3)
