--- libev/ev.html 2007/11/23 04:36:03 1.31 +++ libev/ev.html 2007/11/23 05:14:58 1.32 @@ -6,7 +6,7 @@ - + @@ -125,6 +125,22 @@ compatible to older versions, so a larger minor version alone is usually not a problem.

unsigned int ev_supported_backends ()

Return the set of all backends (i.e. their corresponding EV_BACKEND_* +value) compiled into this binary of libev (independent of their +availability on the system you are running on). See ev_default_loop for +a description of the set values.

unsigned int ev_recommended_backends ()

Return the set of all backends compiled into this binary of libev and also +recommended for this platform. This set is often smaller than the one +returned by ev_supported_backends, as for example kqueue is broken on +most BSDs and will not be autodetected unless you explicitly request it +(assuming you know what you are doing). This is the set of backends that +EVFLAG_AUTO will probe for.

ev_set_allocator (void *(*cb)(void *ptr, long size))

Sets the allocation function to use (the prototype is similar to the @@ -166,11 +182,11 @@

This will initialise the default event loop if it hasn't been initialised yet and return it. If the default loop could not be initialised, returns false. If it already was initialised it simply returns it (and ignores the -flags).

+flags. If that is troubling you, check ev_backend () afterwards).

If you don't know what event loop to use, use the one returned from this function.

The flags argument can be used to specify special behaviour or specific -backends to use, and is usually specified as 0 (or EVFLAG_AUTO).

+backends to use, and is usually specified as 0 (or EVFLAG_AUTO).

It supports the following flags:

@@ -188,7 +204,7 @@ useful to try out specific backends to test their performance, or to work around bugs.

EVMETHOD_SELECT (value 1, portable select backend)

EVBACKEND_SELECT (value 1, portable select backend)

This is your standard select(2) backend. Not completely standard, as libev tries to roll its own fd_set with no limits on the number of fds, @@ -196,14 +212,14 @@ using this backend. It doesn't scale too well (O(highest_fd)), but its usually the fastest backend for a low number of fds.

EVMETHOD_POLL (value 2, poll backend, available everywhere except on windows)

EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)

And this is your standard poll(2) backend. It's more complicated than select, but handles sparse fds better and has no artificial limit on the number of fds you can use (except it will slow down considerably with a lot of inactive fds). It scales similarly to select, i.e. O(total_fds).

EVMETHOD_EPOLL (value 4, Linux)

EVBACKEND_EPOLL (value 4, Linux)

For few fds, this backend is a bit little slower than poll and select, but it scales phenomenally better. While poll and select usually scale like @@ -215,7 +231,7 @@ best to avoid that. Also, dup()ed file descriptors might not work very well if you register events for both fds.

EVMETHOD_KQUEUE (value 8, most BSD clones)

EVBACKEND_KQUEUE (value 8, most BSD clones)

Kqueue deserves special mention, as at the time of this writing, it was broken on all BSDs except NetBSD (usually it doesn't work with @@ -228,20 +244,20 @@ extra syscall as with epoll, it still adds up to four event changes per incident, so its best to avoid that.

EVMETHOD_DEVPOLL (value 16, Solaris 8)

EVBACKEND_DEVPOLL (value 16, Solaris 8)

This is not implemented yet (and might never be).

EVMETHOD_PORT (value 32, Solaris 10)

EVBACKEND_PORT (value 32, Solaris 10)

This uses the Solaris 10 port mechanism. As with everything on Solaris, it's really slow, but it still scales very well (O(active_fds)).

EVMETHOD_ALL

EVBACKEND_ALL

Try all backends (even potentially broken ones that wouldn't be tried with EVFLAG_AUTO). Since this is a mask, you can do stuff such as -EVMETHOD_ALL & ~EVMETHOD_KQUEUE.

+EVBACKEND_ALL & ~EVBACKEND_KQUEUE.

@@ -283,6 +299,9 @@

    pthread_atfork (0, 0, ev_default_fork);

At the moment, EVBACKEND_SELECT and EVBACKEND_POLL are safe to use +without calling this function, so if you force one of those backends you +do not need to care.

ev_loop_fork (loop)

@@ -290,9 +309,9 @@ ev_loop_new. Yes, you have to call this on every allocated event loop after fork, and how you do this is entirely your own problem.

unsigned int ev_method (loop)

unsigned int ev_backend (loop)

Returns one of the EVMETHOD_* flags indicating the event backend in +

Returns one of the EVBACKEND_* flags indicating the event backend in use.

ev_tstamp ev_now (loop)

@@ -400,7 +419,7 @@ corresponding stop function (ev_<type>_stop (loop, watcher *).

As long as your watcher is active (has been started but not stopped) you must not touch the values stored in it. Most specifically you must never -reinitialise it or call its set method.

+reinitialise it or call its set macro.

You can check whether an event is active by calling the ev_is_active (watcher *) macro. To see whether an event is outstanding (but the callback for it has not been called yet) you can use the ev_is_pending @@ -522,8 +541,8 @@ to the same underlying file/socket etc. description (that is, they share the same underlying "file open").


 If you must do this, then force the use of a known-to-be-good backend
-(at the time of this writing, this includes only EVMETHOD_SELECT and
-EVMETHOD_POLL).
+(at the time of this writing, this includes only EVBACKEND_SELECT and
+EVBACKEND_POLL).
 
 	ev_io_init (ev_io *, callback, int fd, int events)
 	ev_io_set (ev_io *, int fd, int events)