X-Git-Url: https://git.llucax.com/software/libev.git/blobdiff_plain/b5f3175db054d9930a6e75d2034e367b36e875b8..1bb2b69718177b8e0629011eefd932b9ef9ee219:/ev.html diff --git a/ev.html b/ev.html index b82e54e..4f2d1fc 100644 --- a/ev.html +++ b/ev.html @@ -6,7 +6,7 @@ - + @@ -275,7 +275,7 @@ more generic mechanism.

Can be used to make a call to ev_loop return early (but only after it has processed all outstanding events). The how argument must be either -EVUNLOOP_ONCE, which will make the innermost ev_loop call return, or +EVUNLOOP_ONE, which will make the innermost ev_loop call return, or EVUNLOOP_ALL, which will make all nested ev_loop calls return.

ev_ref (loop)

@@ -444,14 +444,15 @@ in each iteration of the event loop (This behaviour is called level-triggering because you keep receiving events as long as the condition persists. Remember you can stop the watcher if you don't want to act on the event and neither want to receive future events).

In general you can register as many read and/or write event watchers oer +

In general you can register as many read and/or write event watchers per fd as you want (as long as you don't confuse yourself). Setting all file descriptors to non-blocking mode is also usually a good idea (but not required if you know what you are doing).

You have to be careful with dup'ed file descriptors, though. Some backends (the linux epoll backend is a notable example) cannot handle dup'ed file descriptors correctly if you register interest in two or more fds pointing -to the same file/socket etc. description.

+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).

@@ -471,7 +472,7 @@ EV_WRITE to receive the given events.

Timer watchers are simple relative timers that generate an event after a given time, and optionally repeating in regular intervals after that.

The timers are based on real time, that is, if you register an event that -times out after an hour and youreset your system clock to last years +times out after an hour and you reset your system clock to last years 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).

@@ -479,7 +480,7 @@ monotonic clock option helps a lot here).

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:

+on the current time, use something like this to adjust for this:

   ev_timer_set (&timer, after + ev_now () - ev_time (), 0.);

@@ -494,7 +495,7 @@ later, again, and again, until stopped manually.

The timer itself will do a best-effort at avoiding drift, that is, if you configure a timer to trigger every 10 seconds, then it will trigger at exactly 10 second intervals. If, however, your program cannot keep up with -the timer (ecause it takes longer than those 10 seconds to do stuff) the +the timer (because it takes longer than those 10 seconds to do stuff) the timer will not fire more than once per event loop iteration.

ev_timer_again (loop)

@@ -719,7 +720,7 @@ macros, but using them is utterly, utterly and completely pointless.

This function combines a simple timer and an I/O watcher, calls your callback on whichever event happens first and automatically stop both watchers. This is useful if you want to wait for a single event on an fd -or timeout without havign to allocate/configure/start/stop/free one or +or timeout without having to allocate/configure/start/stop/free one or more watchers yourself.

If fd is less than 0, then no I/O watcher will be started and events is being ignored. Otherwise, an ev_io watcher for the given fd and @@ -729,7 +730,7 @@ started. Otherwise an ev_timer watcher with after = timeout0 is a valid timeout, it is of dubious value.

The callback has the type void (*cb)(int revents, void *arg) and gets -passed an events set like normal event callbacks (with a combination of +passed an revents set like normal event callbacks (a combination of EV_ERROR, EV_READ, EV_WRITE or EV_TIMEOUT) and the arg value passed to ev_once:

  static void stdin_ready (int revents, void *arg)
@@ -764,7 +765,22 @@ the given events it.
 
 LIBEVENT EMULATION
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-TBD.
+Libev offers a compatibility emulation layer for libevent. It cannot
+emulate the internals of libevent, so here are some usage hints:
+
+	* Use it by including <event.h>, as usual.
+	* The following members are fully supported: ev_base, ev_callback,
+ev_arg, ev_fd, ev_res, ev_events.
+	* Avoid using ev_flags and the EVLIST_*-macros, while it is
+maintained by libev, it does not work exactly the same way as in libevent (consider
+it a private API).
+	* Priorities are not currently supported. Initialising priorities
+will fail and all watchers will have the same priority, even though there
+is an ev_pri field.
+	* Other members are not supported.
+	* The libev emulation is not ABI compatible to libevent, you need
+to use the libev header file and library.
+
 
 
 C++ SUPPORT
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