diff options
Diffstat (limited to 'ev.pod')
| -rw-r--r-- | ev.pod | 66 |
1 files changed, 38 insertions, 28 deletions
@@ -65,7 +65,7 @@ C<ev_version_minor>. If you want, you can compare against the global symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the version of the library your program was compiled against. -Usually, its a good idea to terminate if the major versions mismatch, +Usually, it's a good idea to terminate if the major versions mismatch, as this indicates an incompatible change. Minor versions are usually compatible to older versions, so a larger minor version alone is usually not a problem. @@ -105,7 +105,7 @@ in your main thread (or in a separate thrad) and for each thread you create, you also create another event loop. Libev itself does no locking whatsoever, so if you mix calls to the same event loop in different threads, make sure you lock (this is usually a bad idea, though, even if -done correctly, because its hideous and inefficient). +done correctly, because it's hideous and inefficient). =over 4 @@ -128,7 +128,7 @@ It supports the following flags: =item EVFLAG_AUTO -The default flags value. Use this if you have no clue (its the right +The default flags value. Use this if you have no clue (it's the right thing, believe me). =item EVFLAG_NOENV @@ -140,17 +140,17 @@ override the flags completely if it is found in the environment. This is useful to try out specific backends to test their performance, or to work around bugs. -=item EVMETHOD_SELECT portable select backend +=item EVMETHOD_SELECT (portable select backend) -=item EVMETHOD_POLL poll backend (everywhere except windows) +=item EVMETHOD_POLL (poll backend, available everywhere except on windows) -=item EVMETHOD_EPOLL linux only +=item EVMETHOD_EPOLL (linux only) -=item EVMETHOD_KQUEUE some bsds only +=item EVMETHOD_KQUEUE (some bsds only) -=item EVMETHOD_DEVPOLL solaris 8 only +=item EVMETHOD_DEVPOLL (solaris 8 only) -=item EVMETHOD_PORT solaris 10 only +=item EVMETHOD_PORT (solaris 10 only) If one or more of these are ored into the flags value, then only these backends will be tried (in the reverse order as given here). If one are @@ -169,7 +169,7 @@ undefined behaviour (or a failed assertion if assertions are enabled). Destroys the default loop again (frees all memory and kernel state etc.). This stops all registered event watchers (by not touching them in -any way whatsoever, although you cnanot rely on this :). +any way whatsoever, although you cannot rely on this :). =item ev_loop_destroy (loop) @@ -187,7 +187,7 @@ You I<must> call this function after forking if and only if you want to use the event library in both processes. If you just fork+exec, you don't have to call it. -The function itself is quite fast and its usually not a problem to call +The function itself is quite fast and it's usually not a problem to call it just in case after a fork. To make this easy, the function will fit in quite nicely into a call to C<pthread_atfork>: @@ -204,7 +204,7 @@ after fork, and how you do this is entirely your own problem. Returns one of the C<EVMETHOD_*> flags indicating the event backend in use. -=item ev_tstamp = ev_now (loop) +=item ev_tstamp ev_now (loop) Returns the current "event loop time", which is the time the event loop got events and started processing them. This timestamp does not change @@ -223,11 +223,12 @@ no event watchers are active anymore or C<ev_unloop> was called. A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle those events and any outstanding ones, but will not block your process in -case there are no events. +case there are no events and will return after one iteration of the loop. A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if neccessary) and will handle those and any outstanding ones. It will block -your process until at least one new event arrives. +your process until at least one new event arrives, and will return after +one iteration of the loop. This flags value could be used to implement alternative looping constructs, but the C<prepare> and C<check> watchers provide a better and @@ -235,24 +236,25 @@ more generic mechanism. =item ev_unloop (loop, how) -Can be used to make a call to C<ev_loop> return early. The C<how> argument -must be either C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> -call return, or C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> -calls return. +Can be used to make a call to C<ev_loop> return early (but only after it +has processed all outstanding events). The C<how> argument must be either +C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> call return, or +C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. =item ev_ref (loop) =item ev_unref (loop) -Ref/unref can be used to add or remove a refcount on the event loop: Every -watcher keeps one reference. If you have a long-runing watcher you never -unregister that should not keep ev_loop from running, ev_unref() after -starting, and ev_ref() before stopping it. Libev itself uses this for -example for its internal signal pipe: It is not visible to you as a user -and should not keep C<ev_loop> from exiting if the work is done. It is -also an excellent way to do this for generic recurring timers or from -within third-party libraries. Just remember to unref after start and ref -before stop. +Ref/unref can be used to add or remove a reference count on the event +loop: Every watcher keeps one reference, and as long as the reference +count is nonzero, C<ev_loop> will not return on its own. If you have +a watcher you never unregister that should not keep C<ev_loop> from +returning, ev_unref() after starting, and ev_ref() before stopping it. For +example, libev itself uses this for its internal signal pipe: It is not +visible to the libev user and should not keep C<ev_loop> from exiting if +no event watchers registered by it are active. It is also an excellent +way to do this for generic recurring timers or from within third-party +libraries. Just remember to I<unref after start> and I<ref before stop>. =back @@ -449,6 +451,14 @@ time, it will still time out after (roughly) and hour. "Roughly" because detecting time jumps is hard, and soem inaccuracies are unavoidable (the monotonic clock option helps a lot here). +The relative timeouts are calculated relative to the C<ev_now ()> +time. This is usually the right thing as this timestamp refers to the time +of the event triggering whatever timeout you are modifying/starting. If +you suspect event processing to be delayed and you *need* to base the timeout +ion the current time, use something like this to adjust for this: + + ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); + =over 4 =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) @@ -587,7 +597,7 @@ program when the crontabs have changed). Signal watchers will trigger an event when the process receives a specific signal one or more times. Even though signals are very asynchronous, libev -will try its best to deliver signals synchronously, i.e. as part of the +will try it's best to deliver signals synchronously, i.e. as part of the normal event processing, like any other event. You cna configure as many watchers as you like per signal. Only when the |