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4 | <head> |
4 | <head> |
5 | <title>libev</title> |
5 | <title>libev</title> |
6 | <meta name="description" content="Pod documentation for libev" /> |
6 | <meta name="description" content="Pod documentation for libev" /> |
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9 | <meta name="created" content="Sat Nov 24 05:58:35 2007" /> |
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13 | <div class="pod"> |
13 | <div class="pod"> |
14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
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21 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
21 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
22 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
22 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
23 | <li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li> |
23 | <li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li> |
24 | <li><a href="#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</a></li> |
24 | <li><a href="#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</a></li> |
25 | <li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a> |
25 | <li><a href="#ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</a> |
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26 | <ul><li><a href="#GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</a></li> |
26 | <ul><li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li> |
27 | <li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li> |
27 | </ul> |
28 | </ul> |
28 | </li> |
29 | </li> |
29 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
30 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
30 | <ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</a></li> |
31 | <ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a></li> |
31 | <li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</a></li> |
32 | <li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li> |
32 | <li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</a></li> |
33 | <li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a></li> |
33 | <li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</a></li> |
34 | <li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li> |
34 | <li><a href="#code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</a></li> |
35 | <li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a></li> |
35 | <li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</a></li> |
36 | <li><a href="#code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</a></li> |
36 | <li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</a></li> |
37 | <li><a href="#code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</a></li> |
37 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</a></li> |
38 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li> |
38 | </ul> |
39 | </ul> |
39 | </li> |
40 | </li> |
40 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
41 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
41 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
42 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
42 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
43 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
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44 | <li><a href="#EMBEDDING">EMBEDDING</a> |
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45 | <ul><li><a href="#FILESETS">FILESETS</a> |
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46 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
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47 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
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48 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
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49 | </ul> |
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50 | </li> |
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51 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
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52 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
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53 | </ul> |
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54 | </li> |
43 | <li><a href="#AUTHOR">AUTHOR</a> |
55 | <li><a href="#AUTHOR">AUTHOR</a> |
44 | </li> |
56 | </li> |
45 | </ul><hr /> |
57 | </ul><hr /> |
46 | <!-- INDEX END --> |
58 | <!-- INDEX END --> |
47 | |
59 | |
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363 | </pre> |
375 | </pre> |
364 | </dd> |
376 | </dd> |
365 | <dt>ev_default_destroy ()</dt> |
377 | <dt>ev_default_destroy ()</dt> |
366 | <dd> |
378 | <dd> |
367 | <p>Destroys the default loop again (frees all memory and kernel state |
379 | <p>Destroys the default loop again (frees all memory and kernel state |
368 | etc.). This stops all registered event watchers (by not touching them in |
380 | etc.). None of the active event watchers will be stopped in the normal |
369 | any way whatsoever, although you cannot rely on this :).</p> |
381 | sense, so e.g. <code>ev_is_active</code> might still return true. It is your |
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382 | responsibility to either stop all watchers cleanly yoursef <i>before</i> |
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383 | calling this function, or cope with the fact afterwards (which is usually |
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384 | the easiest thing, youc na just ignore the watchers and/or <code>free ()</code> them |
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385 | for example).</p> |
370 | </dd> |
386 | </dd> |
371 | <dt>ev_loop_destroy (loop)</dt> |
387 | <dt>ev_loop_destroy (loop)</dt> |
372 | <dd> |
388 | <dd> |
373 | <p>Like <code>ev_default_destroy</code>, but destroys an event loop created by an |
389 | <p>Like <code>ev_default_destroy</code>, but destroys an event loop created by an |
374 | earlier call to <code>ev_loop_new</code>.</p> |
390 | earlier call to <code>ev_loop_new</code>.</p> |
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497 | |
513 | |
498 | </pre> |
514 | </pre> |
499 | </dd> |
515 | </dd> |
500 | </dl> |
516 | </dl> |
501 | |
517 | |
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518 | |
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519 | |
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520 | |
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521 | |
502 | </div> |
522 | </div> |
503 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
523 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
504 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
524 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
505 | <p>A watcher is a structure that you create and register to record your |
525 | <p>A watcher is a structure that you create and register to record your |
506 | interest in some event. For instance, if you want to wait for STDIN to |
526 | interest in some event. For instance, if you want to wait for STDIN to |
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535 | with a watcher-specific start function (<code>ev_<type>_start (loop, watcher |
555 | with a watcher-specific start function (<code>ev_<type>_start (loop, watcher |
536 | *)</code>), and you can stop watching for events at any time by calling the |
556 | *)</code>), and you can stop watching for events at any time by calling the |
537 | corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p> |
557 | corresponding stop function (<code>ev_<type>_stop (loop, watcher *)</code>.</p> |
538 | <p>As long as your watcher is active (has been started but not stopped) you |
558 | <p>As long as your watcher is active (has been started but not stopped) you |
539 | must not touch the values stored in it. Most specifically you must never |
559 | must not touch the values stored in it. Most specifically you must never |
540 | reinitialise it or call its set macro.</p> |
560 | reinitialise it or call its <code>set</code> macro.</p> |
541 | <p>You can check whether an event is active by calling the <code>ev_is_active |
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542 | (watcher *)</code> macro. To see whether an event is outstanding (but the |
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543 | callback for it has not been called yet) you can use the <code>ev_is_pending |
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544 | (watcher *)</code> macro.</p> |
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545 | <p>Each and every callback receives the event loop pointer as first, the |
561 | <p>Each and every callback receives the event loop pointer as first, the |
546 | registered watcher structure as second, and a bitset of received events as |
562 | registered watcher structure as second, and a bitset of received events as |
547 | third argument.</p> |
563 | third argument.</p> |
548 | <p>The received events usually include a single bit per event type received |
564 | <p>The received events usually include a single bit per event type received |
549 | (you can receive multiple events at the same time). The possible bit masks |
565 | (you can receive multiple events at the same time). The possible bit masks |
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598 | your callbacks is well-written it can just attempt the operation and cope |
614 | your callbacks is well-written it can just attempt the operation and cope |
599 | with the error from read() or write(). This will not work in multithreaded |
615 | with the error from read() or write(). This will not work in multithreaded |
600 | programs, though, so beware.</p> |
616 | programs, though, so beware.</p> |
601 | </dd> |
617 | </dd> |
602 | </dl> |
618 | </dl> |
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619 | |
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620 | </div> |
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621 | <h2 id="GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</h2> |
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622 | <div id="GENERIC_WATCHER_FUNCTIONS_CONTENT"> |
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623 | <p>In the following description, <code>TYPE</code> stands for the watcher type, |
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624 | e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p> |
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625 | <dl> |
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626 | <dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt> |
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627 | <dd> |
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628 | <p>This macro initialises the generic portion of a watcher. The contents |
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629 | of the watcher object can be arbitrary (so <code>malloc</code> will do). Only |
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630 | the generic parts of the watcher are initialised, you <i>need</i> to call |
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631 | the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the |
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632 | type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro |
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633 | which rolls both calls into one.</p> |
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634 | <p>You can reinitialise a watcher at any time as long as it has been stopped |
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635 | (or never started) and there are no pending events outstanding.</p> |
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636 | <p>The callback is always of type <code>void (*)(ev_loop *loop, ev_TYPE *watcher, |
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637 | int revents)</code>.</p> |
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638 | </dd> |
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639 | <dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt> |
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640 | <dd> |
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641 | <p>This macro initialises the type-specific parts of a watcher. You need to |
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642 | call <code>ev_init</code> at least once before you call this macro, but you can |
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643 | call <code>ev_TYPE_set</code> any number of times. You must not, however, call this |
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644 | macro on a watcher that is active (it can be pending, however, which is a |
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645 | difference to the <code>ev_init</code> macro).</p> |
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646 | <p>Although some watcher types do not have type-specific arguments |
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647 | (e.g. <code>ev_prepare</code>) you still need to call its <code>set</code> macro.</p> |
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648 | </dd> |
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649 | <dt><code>ev_TYPE_init</code> (ev_TYPE *watcher, callback, [args])</dt> |
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650 | <dd> |
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651 | <p>This convinience macro rolls both <code>ev_init</code> and <code>ev_TYPE_set</code> macro |
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652 | calls into a single call. This is the most convinient method to initialise |
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653 | a watcher. The same limitations apply, of course.</p> |
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654 | </dd> |
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655 | <dt><code>ev_TYPE_start</code> (loop *, ev_TYPE *watcher)</dt> |
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656 | <dd> |
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657 | <p>Starts (activates) the given watcher. Only active watchers will receive |
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658 | events. If the watcher is already active nothing will happen.</p> |
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659 | </dd> |
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660 | <dt><code>ev_TYPE_stop</code> (loop *, ev_TYPE *watcher)</dt> |
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661 | <dd> |
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662 | <p>Stops the given watcher again (if active) and clears the pending |
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663 | status. It is possible that stopped watchers are pending (for example, |
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664 | non-repeating timers are being stopped when they become pending), but |
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665 | <code>ev_TYPE_stop</code> ensures that the watcher is neither active nor pending. If |
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666 | you want to free or reuse the memory used by the watcher it is therefore a |
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667 | good idea to always call its <code>ev_TYPE_stop</code> function.</p> |
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668 | </dd> |
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669 | <dt>bool ev_is_active (ev_TYPE *watcher)</dt> |
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670 | <dd> |
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671 | <p>Returns a true value iff the watcher is active (i.e. it has been started |
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672 | and not yet been stopped). As long as a watcher is active you must not modify |
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673 | it.</p> |
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674 | </dd> |
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675 | <dt>bool ev_is_pending (ev_TYPE *watcher)</dt> |
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676 | <dd> |
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677 | <p>Returns a true value iff the watcher is pending, (i.e. it has outstanding |
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678 | events but its callback has not yet been invoked). As long as a watcher |
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679 | is pending (but not active) you must not call an init function on it (but |
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680 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
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681 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
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682 | </dd> |
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683 | <dt>callback = ev_cb (ev_TYPE *watcher)</dt> |
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684 | <dd> |
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685 | <p>Returns the callback currently set on the watcher.</p> |
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686 | </dd> |
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687 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
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688 | <dd> |
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689 | <p>Change the callback. You can change the callback at virtually any time |
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690 | (modulo threads).</p> |
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691 | </dd> |
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692 | </dl> |
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693 | |
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694 | |
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695 | |
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696 | |
603 | |
697 | |
604 | </div> |
698 | </div> |
605 | <h2 id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</h2> |
699 | <h2 id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</h2> |
606 | <div id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH-2"> |
700 | <div id="ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH-2"> |
607 | <p>Each watcher has, by default, a member <code>void *data</code> that you can change |
701 | <p>Each watcher has, by default, a member <code>void *data</code> that you can change |
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644 | |
738 | |
645 | |
739 | |
646 | |
740 | |
647 | |
741 | |
648 | </div> |
742 | </div> |
649 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2> |
743 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</h2> |
650 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
744 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
651 | <p>I/O watchers check whether a file descriptor is readable or writable |
745 | <p>I/O watchers check whether a file descriptor is readable or writable |
652 | in each iteration of the event loop (This behaviour is called |
746 | in each iteration of the event loop, or, more precisely, when reading |
653 | level-triggering because you keep receiving events as long as the |
747 | would not block the process and writing would at least be able to write |
654 | condition persists. Remember you can stop the watcher if you don't want to |
748 | some data. This behaviour is called level-triggering because you keep |
655 | act on the event and neither want to receive future events).</p> |
749 | receiving events as long as the condition persists. Remember you can stop |
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750 | the watcher if you don't want to act on the event and neither want to |
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751 | receive future events.</p> |
656 | <p>In general you can register as many read and/or write event watchers per |
752 | <p>In general you can register as many read and/or write event watchers per |
657 | fd as you want (as long as you don't confuse yourself). Setting all file |
753 | fd as you want (as long as you don't confuse yourself). Setting all file |
658 | descriptors to non-blocking mode is also usually a good idea (but not |
754 | descriptors to non-blocking mode is also usually a good idea (but not |
659 | required if you know what you are doing).</p> |
755 | required if you know what you are doing).</p> |
660 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
756 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
661 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
757 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
662 | descriptors correctly if you register interest in two or more fds pointing |
758 | descriptors correctly if you register interest in two or more fds pointing |
663 | to the same underlying file/socket etc. description (that is, they share |
759 | to the same underlying file/socket/etc. description (that is, they share |
664 | the same underlying "file open").</p> |
760 | the same underlying "file open").</p> |
665 | <p>If you must do this, then force the use of a known-to-be-good backend |
761 | <p>If you must do this, then force the use of a known-to-be-good backend |
666 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
762 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
667 | <code>EVBACKEND_POLL</code>).</p> |
763 | <code>EVBACKEND_POLL</code>).</p> |
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764 | <p>Another thing you have to watch out for is that it is quite easy to |
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765 | receive "spurious" readyness notifications, that is your callback might |
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766 | be called with <code>EV_READ</code> but a subsequent <code>read</code>(2) will actually block |
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767 | because there is no data. Not only are some backends known to create a |
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768 | lot of those (for example solaris ports), it is very easy to get into |
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769 | this situation even with a relatively standard program structure. Thus |
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770 | it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning |
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771 | <code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p> |
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772 | <p>If you cannot run the fd in non-blocking mode (for example you should not |
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773 | play around with an Xlib connection), then you have to seperately re-test |
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774 | wether a file descriptor is really ready with a known-to-be good interface |
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775 | such as poll (fortunately in our Xlib example, Xlib already does this on |
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776 | its own, so its quite safe to use).</p> |
668 | <dl> |
777 | <dl> |
669 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
778 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
670 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
779 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
671 | <dd> |
780 | <dd> |
672 | <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive |
781 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
673 | events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ | |
782 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
674 | EV_WRITE</code> to receive the given events.</p> |
783 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
675 | <p>Please note that most of the more scalable backend mechanisms (for example |
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676 | epoll and solaris ports) can result in spurious readyness notifications |
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677 | for file descriptors, so you practically need to use non-blocking I/O (and |
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678 | treat callback invocation as hint only), or retest separately with a safe |
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679 | interface before doing I/O (XLib can do this), or force the use of either |
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680 | <code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this |
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681 | problem. Also note that it is quite easy to have your callback invoked |
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682 | when the readyness condition is no longer valid even when employing |
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683 | typical ways of handling events, so its a good idea to use non-blocking |
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684 | I/O unconditionally.</p> |
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685 | </dd> |
784 | </dd> |
686 | </dl> |
785 | </dl> |
687 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
786 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
688 | readable, but only once. Since it is likely line-buffered, you could |
787 | readable, but only once. Since it is likely line-buffered, you could |
689 | attempt to read a whole line in the callback:</p> |
788 | attempt to read a whole line in the callback:</p> |
… | |
… | |
705 | |
804 | |
706 | |
805 | |
707 | </pre> |
806 | </pre> |
708 | |
807 | |
709 | </div> |
808 | </div> |
710 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2> |
809 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</h2> |
711 | <div id="code_ev_timer_code_relative_and_opti-2"> |
810 | <div id="code_ev_timer_code_relative_and_opti-2"> |
712 | <p>Timer watchers are simple relative timers that generate an event after a |
811 | <p>Timer watchers are simple relative timers that generate an event after a |
713 | given time, and optionally repeating in regular intervals after that.</p> |
812 | given time, and optionally repeating in regular intervals after that.</p> |
714 | <p>The timers are based on real time, that is, if you register an event that |
813 | <p>The timers are based on real time, that is, if you register an event that |
715 | times out after an hour and you reset your system clock to last years |
814 | times out after an hour and you reset your system clock to last years |
… | |
… | |
791 | |
890 | |
792 | |
891 | |
793 | </pre> |
892 | </pre> |
794 | |
893 | |
795 | </div> |
894 | </div> |
796 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2> |
895 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</h2> |
797 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
896 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
798 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
897 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
799 | (and unfortunately a bit complex).</p> |
898 | (and unfortunately a bit complex).</p> |
800 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
899 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
801 | but on wallclock time (absolute time). You can tell a periodic watcher |
900 | but on wallclock time (absolute time). You can tell a periodic watcher |
802 | to trigger "at" some specific point in time. For example, if you tell a |
901 | to trigger "at" some specific point in time. For example, if you tell a |
803 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
902 | periodic watcher to trigger in 10 seconds (by specifiying e.g. <code>ev_now () |
804 | + 10.>) and then reset your system clock to the last year, then it will |
903 | + 10.</code>) and then reset your system clock to the last year, then it will |
805 | take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger |
904 | take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger |
806 | roughly 10 seconds later and of course not if you reset your system time |
905 | roughly 10 seconds later and of course not if you reset your system time |
807 | again).</p> |
906 | again).</p> |
808 | <p>They can also be used to implement vastly more complex timers, such as |
907 | <p>They can also be used to implement vastly more complex timers, such as |
809 | triggering an event on eahc midnight, local time.</p> |
908 | triggering an event on eahc midnight, local time.</p> |
… | |
… | |
920 | |
1019 | |
921 | |
1020 | |
922 | </pre> |
1021 | </pre> |
923 | |
1022 | |
924 | </div> |
1023 | </div> |
925 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2> |
1024 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</h2> |
926 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
1025 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
927 | <p>Signal watchers will trigger an event when the process receives a specific |
1026 | <p>Signal watchers will trigger an event when the process receives a specific |
928 | signal one or more times. Even though signals are very asynchronous, libev |
1027 | signal one or more times. Even though signals are very asynchronous, libev |
929 | will try it's best to deliver signals synchronously, i.e. as part of the |
1028 | will try it's best to deliver signals synchronously, i.e. as part of the |
930 | normal event processing, like any other event.</p> |
1029 | normal event processing, like any other event.</p> |
… | |
… | |
946 | |
1045 | |
947 | |
1046 | |
948 | |
1047 | |
949 | |
1048 | |
950 | </div> |
1049 | </div> |
951 | <h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2> |
1050 | <h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2> |
952 | <div id="code_ev_child_code_wait_for_pid_stat-2"> |
1051 | <div id="code_ev_child_code_watch_out_for_pro-2"> |
953 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
1052 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
954 | some child status changes (most typically when a child of yours dies).</p> |
1053 | some child status changes (most typically when a child of yours dies).</p> |
955 | <dl> |
1054 | <dl> |
956 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
1055 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
957 | <dt>ev_child_set (ev_child *, int pid)</dt> |
1056 | <dt>ev_child_set (ev_child *, int pid)</dt> |
… | |
… | |
979 | |
1078 | |
980 | |
1079 | |
981 | </pre> |
1080 | </pre> |
982 | |
1081 | |
983 | </div> |
1082 | </div> |
984 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2> |
1083 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2> |
985 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1084 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
986 | <p>Idle watchers trigger events when there are no other events are pending |
1085 | <p>Idle watchers trigger events when there are no other events are pending |
987 | (prepare, check and other idle watchers do not count). That is, as long |
1086 | (prepare, check and other idle watchers do not count). That is, as long |
988 | as your process is busy handling sockets or timeouts (or even signals, |
1087 | as your process is busy handling sockets or timeouts (or even signals, |
989 | imagine) it will not be triggered. But when your process is idle all idle |
1088 | imagine) it will not be triggered. But when your process is idle all idle |
… | |
… | |
1022 | |
1121 | |
1023 | |
1122 | |
1024 | </pre> |
1123 | </pre> |
1025 | |
1124 | |
1026 | </div> |
1125 | </div> |
1027 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2> |
1126 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2> |
1028 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1127 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1029 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1128 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1030 | prepare watchers get invoked before the process blocks and check watchers |
1129 | prepare watchers get invoked before the process blocks and check watchers |
1031 | afterwards.</p> |
1130 | afterwards.</p> |
1032 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1131 | <p>Their main purpose is to integrate other event mechanisms into libev and |
… | |
… | |
1063 | |
1162 | |
1064 | |
1163 | |
1065 | |
1164 | |
1066 | |
1165 | |
1067 | </div> |
1166 | </div> |
1068 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</h2> |
1167 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1069 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1168 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1070 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1169 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1071 | into another.</p> |
1170 | into another (currently only <code>ev_io</code> events are supported in the embedded |
|
|
1171 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1172 | fashion and must not be used).</p> |
1072 | <p>There are primarily two reasons you would want that: work around bugs and |
1173 | <p>There are primarily two reasons you would want that: work around bugs and |
1073 | prioritise I/O.</p> |
1174 | prioritise I/O.</p> |
1074 | <p>As an example for a bug workaround, the kqueue backend might only support |
1175 | <p>As an example for a bug workaround, the kqueue backend might only support |
1075 | sockets on some platform, so it is unusable as generic backend, but you |
1176 | sockets on some platform, so it is unusable as generic backend, but you |
1076 | still want to make use of it because you have many sockets and it scales |
1177 | still want to make use of it because you have many sockets and it scales |
… | |
… | |
1081 | <p>As for prioritising I/O: rarely you have the case where some fds have |
1182 | <p>As for prioritising I/O: rarely you have the case where some fds have |
1082 | to be watched and handled very quickly (with low latency), and even |
1183 | to be watched and handled very quickly (with low latency), and even |
1083 | priorities and idle watchers might have too much overhead. In this case |
1184 | priorities and idle watchers might have too much overhead. In this case |
1084 | you would put all the high priority stuff in one loop and all the rest in |
1185 | you would put all the high priority stuff in one loop and all the rest in |
1085 | a second one, and embed the second one in the first.</p> |
1186 | a second one, and embed the second one in the first.</p> |
|
|
1187 | <p>As long as the watcher is active, the callback will be invoked every time |
|
|
1188 | there might be events pending in the embedded loop. The callback must then |
|
|
1189 | call <code>ev_embed_sweep (mainloop, watcher)</code> to make a single sweep and invoke |
|
|
1190 | their callbacks (you could also start an idle watcher to give the embedded |
|
|
1191 | loop strictly lower priority for example). You can also set the callback |
|
|
1192 | to <code>0</code>, in which case the embed watcher will automatically execute the |
|
|
1193 | embedded loop sweep.</p> |
1086 | <p>As long as the watcher is started it will automatically handle events. The |
1194 | <p>As long as the watcher is started it will automatically handle events. The |
1087 | callback will be invoked whenever some events have been handled. You can |
1195 | callback will be invoked whenever some events have been handled. You can |
1088 | set the callback to <code>0</code> to avoid having to specify one if you are not |
1196 | set the callback to <code>0</code> to avoid having to specify one if you are not |
1089 | interested in that.</p> |
1197 | interested in that.</p> |
1090 | <p>Also, there have not currently been made special provisions for forking: |
1198 | <p>Also, there have not currently been made special provisions for forking: |
… | |
… | |
1117 | else |
1225 | else |
1118 | loop_lo = loop_hi; |
1226 | loop_lo = loop_hi; |
1119 | |
1227 | |
1120 | </pre> |
1228 | </pre> |
1121 | <dl> |
1229 | <dl> |
1122 | <dt>ev_embed_init (ev_embed *, callback, struct ev_loop *loop)</dt> |
1230 | <dt>ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)</dt> |
1123 | <dt>ev_embed_set (ev_embed *, callback, struct ev_loop *loop)</dt> |
1231 | <dt>ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)</dt> |
|
|
1232 | <dd> |
|
|
1233 | <p>Configures the watcher to embed the given loop, which must be |
|
|
1234 | embeddable. If the callback is <code>0</code>, then <code>ev_embed_sweep</code> will be |
|
|
1235 | invoked automatically, otherwise it is the responsibility of the callback |
|
|
1236 | to invoke it (it will continue to be called until the sweep has been done, |
|
|
1237 | if you do not want thta, you need to temporarily stop the embed watcher).</p> |
1124 | <dd> |
1238 | </dd> |
1125 | <p>Configures the watcher to embed the given loop, which must be embeddable.</p> |
1239 | <dt>ev_embed_sweep (loop, ev_embed *)</dt> |
|
|
1240 | <dd> |
|
|
1241 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
|
|
1242 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
|
|
1243 | apropriate way for embedded loops.</p> |
1126 | </dd> |
1244 | </dd> |
1127 | </dl> |
1245 | </dl> |
1128 | |
1246 | |
1129 | |
1247 | |
1130 | |
1248 | |
… | |
… | |
1163 | |
1281 | |
1164 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1282 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
1165 | |
1283 | |
1166 | </pre> |
1284 | </pre> |
1167 | </dd> |
1285 | </dd> |
1168 | <dt>ev_feed_event (loop, watcher, int events)</dt> |
1286 | <dt>ev_feed_event (ev_loop *, watcher *, int revents)</dt> |
1169 | <dd> |
1287 | <dd> |
1170 | <p>Feeds the given event set into the event loop, as if the specified event |
1288 | <p>Feeds the given event set into the event loop, as if the specified event |
1171 | had happened for the specified watcher (which must be a pointer to an |
1289 | had happened for the specified watcher (which must be a pointer to an |
1172 | initialised but not necessarily started event watcher).</p> |
1290 | initialised but not necessarily started event watcher).</p> |
1173 | </dd> |
1291 | </dd> |
1174 | <dt>ev_feed_fd_event (loop, int fd, int revents)</dt> |
1292 | <dt>ev_feed_fd_event (ev_loop *, int fd, int revents)</dt> |
1175 | <dd> |
1293 | <dd> |
1176 | <p>Feed an event on the given fd, as if a file descriptor backend detected |
1294 | <p>Feed an event on the given fd, as if a file descriptor backend detected |
1177 | the given events it.</p> |
1295 | the given events it.</p> |
1178 | </dd> |
1296 | </dd> |
1179 | <dt>ev_feed_signal_event (loop, int signum)</dt> |
1297 | <dt>ev_feed_signal_event (ev_loop *loop, int signum)</dt> |
1180 | <dd> |
1298 | <dd> |
1181 | <p>Feed an event as if the given signal occured (loop must be the default loop!).</p> |
1299 | <p>Feed an event as if the given signal occured (<code>loop</code> must be the default |
|
|
1300 | loop!).</p> |
1182 | </dd> |
1301 | </dd> |
1183 | </dl> |
1302 | </dl> |
1184 | |
1303 | |
1185 | |
1304 | |
1186 | |
1305 | |
… | |
… | |
1207 | </dl> |
1326 | </dl> |
1208 | |
1327 | |
1209 | </div> |
1328 | </div> |
1210 | <h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1329 | <h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1211 | <div id="C_SUPPORT_CONTENT"> |
1330 | <div id="C_SUPPORT_CONTENT"> |
1212 | <p>TBD.</p> |
1331 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
|
|
1332 | you to use some convinience methods to start/stop watchers and also change |
|
|
1333 | the callback model to a model using method callbacks on objects.</p> |
|
|
1334 | <p>To use it,</p> |
|
|
1335 | <pre> #include <ev++.h> |
|
|
1336 | |
|
|
1337 | </pre> |
|
|
1338 | <p>(it is not installed by default). This automatically includes <cite>ev.h</cite> |
|
|
1339 | and puts all of its definitions (many of them macros) into the global |
|
|
1340 | namespace. All C++ specific things are put into the <code>ev</code> namespace.</p> |
|
|
1341 | <p>It should support all the same embedding options as <cite>ev.h</cite>, most notably |
|
|
1342 | <code>EV_MULTIPLICITY</code>.</p> |
|
|
1343 | <p>Here is a list of things available in the <code>ev</code> namespace:</p> |
|
|
1344 | <dl> |
|
|
1345 | <dt><code>ev::READ</code>, <code>ev::WRITE</code> etc.</dt> |
|
|
1346 | <dd> |
|
|
1347 | <p>These are just enum values with the same values as the <code>EV_READ</code> etc. |
|
|
1348 | macros from <cite>ev.h</cite>.</p> |
|
|
1349 | </dd> |
|
|
1350 | <dt><code>ev::tstamp</code>, <code>ev::now</code></dt> |
|
|
1351 | <dd> |
|
|
1352 | <p>Aliases to the same types/functions as with the <code>ev_</code> prefix.</p> |
|
|
1353 | </dd> |
|
|
1354 | <dt><code>ev::io</code>, <code>ev::timer</code>, <code>ev::periodic</code>, <code>ev::idle</code>, <code>ev::sig</code> etc.</dt> |
|
|
1355 | <dd> |
|
|
1356 | <p>For each <code>ev_TYPE</code> watcher in <cite>ev.h</cite> there is a corresponding class of |
|
|
1357 | the same name in the <code>ev</code> namespace, with the exception of <code>ev_signal</code> |
|
|
1358 | which is called <code>ev::sig</code> to avoid clashes with the <code>signal</code> macro |
|
|
1359 | defines by many implementations.</p> |
|
|
1360 | <p>All of those classes have these methods:</p> |
|
|
1361 | <p> |
|
|
1362 | <dl> |
|
|
1363 | <dt>ev::TYPE::TYPE (object *, object::method *)</dt> |
|
|
1364 | <dt>ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)</dt> |
|
|
1365 | <dt>ev::TYPE::~TYPE</dt> |
|
|
1366 | <dd> |
|
|
1367 | <p>The constructor takes a pointer to an object and a method pointer to |
|
|
1368 | the event handler callback to call in this class. The constructor calls |
|
|
1369 | <code>ev_init</code> for you, which means you have to call the <code>set</code> method |
|
|
1370 | before starting it. If you do not specify a loop then the constructor |
|
|
1371 | automatically associates the default loop with this watcher.</p> |
|
|
1372 | <p>The destructor automatically stops the watcher if it is active.</p> |
|
|
1373 | </dd> |
|
|
1374 | <dt>w->set (struct ev_loop *)</dt> |
|
|
1375 | <dd> |
|
|
1376 | <p>Associates a different <code>struct ev_loop</code> with this watcher. You can only |
|
|
1377 | do this when the watcher is inactive (and not pending either).</p> |
|
|
1378 | </dd> |
|
|
1379 | <dt>w->set ([args])</dt> |
|
|
1380 | <dd> |
|
|
1381 | <p>Basically the same as <code>ev_TYPE_set</code>, with the same args. Must be |
|
|
1382 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1383 | automatically stopped and restarted.</p> |
|
|
1384 | </dd> |
|
|
1385 | <dt>w->start ()</dt> |
|
|
1386 | <dd> |
|
|
1387 | <p>Starts the watcher. Note that there is no <code>loop</code> argument as the |
|
|
1388 | constructor already takes the loop.</p> |
|
|
1389 | </dd> |
|
|
1390 | <dt>w->stop ()</dt> |
|
|
1391 | <dd> |
|
|
1392 | <p>Stops the watcher if it is active. Again, no <code>loop</code> argument.</p> |
|
|
1393 | </dd> |
|
|
1394 | <dt>w->again () <code>ev::timer</code>, <code>ev::periodic</code> only</dt> |
|
|
1395 | <dd> |
|
|
1396 | <p>For <code>ev::timer</code> and <code>ev::periodic</code>, this invokes the corresponding |
|
|
1397 | <code>ev_TYPE_again</code> function.</p> |
|
|
1398 | </dd> |
|
|
1399 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
|
|
1400 | <dd> |
|
|
1401 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
|
|
1402 | </dd> |
|
|
1403 | </dl> |
|
|
1404 | </p> |
|
|
1405 | </dd> |
|
|
1406 | </dl> |
|
|
1407 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
|
|
1408 | the constructor.</p> |
|
|
1409 | <pre> class myclass |
|
|
1410 | { |
|
|
1411 | ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1412 | ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1413 | |
|
|
1414 | myclass (); |
|
|
1415 | } |
|
|
1416 | |
|
|
1417 | myclass::myclass (int fd) |
|
|
1418 | : io (this, &myclass::io_cb), |
|
|
1419 | idle (this, &myclass::idle_cb) |
|
|
1420 | { |
|
|
1421 | io.start (fd, ev::READ); |
|
|
1422 | } |
|
|
1423 | |
|
|
1424 | </pre> |
|
|
1425 | |
|
|
1426 | </div> |
|
|
1427 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
|
|
1428 | <div id="EMBEDDING_CONTENT"> |
|
|
1429 | <p>Libev can (and often is) directly embedded into host |
|
|
1430 | applications. Examples of applications that embed it include the Deliantra |
|
|
1431 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
|
|
1432 | and rxvt-unicode.</p> |
|
|
1433 | <p>The goal is to enable you to just copy the neecssary files into your |
|
|
1434 | source directory without having to change even a single line in them, so |
|
|
1435 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
1436 | libev somewhere in your source tree).</p> |
|
|
1437 | |
|
|
1438 | </div> |
|
|
1439 | <h2 id="FILESETS">FILESETS</h2> |
|
|
1440 | <div id="FILESETS_CONTENT"> |
|
|
1441 | <p>Depending on what features you need you need to include one or more sets of files |
|
|
1442 | in your app.</p> |
|
|
1443 | |
|
|
1444 | </div> |
|
|
1445 | <h3 id="CORE_EVENT_LOOP">CORE EVENT LOOP</h3> |
|
|
1446 | <div id="CORE_EVENT_LOOP_CONTENT"> |
|
|
1447 | <p>To include only the libev core (all the <code>ev_*</code> functions), with manual |
|
|
1448 | configuration (no autoconf):</p> |
|
|
1449 | <pre> #define EV_STANDALONE 1 |
|
|
1450 | #include "ev.c" |
|
|
1451 | |
|
|
1452 | </pre> |
|
|
1453 | <p>This will automatically include <cite>ev.h</cite>, too, and should be done in a |
|
|
1454 | single C source file only to provide the function implementations. To use |
|
|
1455 | it, do the same for <cite>ev.h</cite> in all files wishing to use this API (best |
|
|
1456 | done by writing a wrapper around <cite>ev.h</cite> that you can include instead and |
|
|
1457 | where you can put other configuration options):</p> |
|
|
1458 | <pre> #define EV_STANDALONE 1 |
|
|
1459 | #include "ev.h" |
|
|
1460 | |
|
|
1461 | </pre> |
|
|
1462 | <p>Both header files and implementation files can be compiled with a C++ |
|
|
1463 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
1464 | as a bug).</p> |
|
|
1465 | <p>You need the following files in your source tree, or in a directory |
|
|
1466 | in your include path (e.g. in libev/ when using -Ilibev):</p> |
|
|
1467 | <pre> ev.h |
|
|
1468 | ev.c |
|
|
1469 | ev_vars.h |
|
|
1470 | ev_wrap.h |
|
|
1471 | |
|
|
1472 | ev_win32.c required on win32 platforms only |
|
|
1473 | |
|
|
1474 | ev_select.c only when select backend is enabled (which is by default) |
|
|
1475 | ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
1476 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
1477 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
1478 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
1479 | |
|
|
1480 | </pre> |
|
|
1481 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
|
|
1482 | to compile this single file.</p> |
|
|
1483 | |
|
|
1484 | </div> |
|
|
1485 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
|
|
1486 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
|
|
1487 | <p>To include the libevent compatibility API, also include:</p> |
|
|
1488 | <pre> #include "event.c" |
|
|
1489 | |
|
|
1490 | </pre> |
|
|
1491 | <p>in the file including <cite>ev.c</cite>, and:</p> |
|
|
1492 | <pre> #include "event.h" |
|
|
1493 | |
|
|
1494 | </pre> |
|
|
1495 | <p>in the files that want to use the libevent API. This also includes <cite>ev.h</cite>.</p> |
|
|
1496 | <p>You need the following additional files for this:</p> |
|
|
1497 | <pre> event.h |
|
|
1498 | event.c |
|
|
1499 | |
|
|
1500 | </pre> |
|
|
1501 | |
|
|
1502 | </div> |
|
|
1503 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
|
|
1504 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
|
|
1505 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
|
|
1506 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
|
|
1507 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> undefined. <cite>ev.c</cite> will then |
|
|
1508 | include <cite>config.h</cite> and configure itself accordingly.</p> |
|
|
1509 | <p>For this of course you need the m4 file:</p> |
|
|
1510 | <pre> libev.m4 |
|
|
1511 | |
|
|
1512 | </pre> |
|
|
1513 | |
|
|
1514 | </div> |
|
|
1515 | <h2 id="PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</h2> |
|
|
1516 | <div id="PREPROCESSOR_SYMBOLS_MACROS_CONTENT"> |
|
|
1517 | <p>Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
1518 | before including any of its files. The default is not to build for multiplicity |
|
|
1519 | and only include the select backend.</p> |
|
|
1520 | <dl> |
|
|
1521 | <dt>EV_STANDALONE</dt> |
|
|
1522 | <dd> |
|
|
1523 | <p>Must always be <code>1</code> if you do not use autoconf configuration, which |
|
|
1524 | keeps libev from including <cite>config.h</cite>, and it also defines dummy |
|
|
1525 | implementations for some libevent functions (such as logging, which is not |
|
|
1526 | supported). It will also not define any of the structs usually found in |
|
|
1527 | <cite>event.h</cite> that are not directly supported by the libev core alone.</p> |
|
|
1528 | </dd> |
|
|
1529 | <dt>EV_USE_MONOTONIC</dt> |
|
|
1530 | <dd> |
|
|
1531 | <p>If defined to be <code>1</code>, libev will try to detect the availability of the |
|
|
1532 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
1533 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
1534 | usually have to link against librt or something similar. Enabling it when |
|
|
1535 | the functionality isn't available is safe, though, althoguh you have |
|
|
1536 | to make sure you link against any libraries where the <code>clock_gettime</code> |
|
|
1537 | function is hiding in (often <cite>-lrt</cite>).</p> |
|
|
1538 | </dd> |
|
|
1539 | <dt>EV_USE_REALTIME</dt> |
|
|
1540 | <dd> |
|
|
1541 | <p>If defined to be <code>1</code>, libev will try to detect the availability of the |
|
|
1542 | realtime clock option at compiletime (and assume its availability at |
|
|
1543 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
1544 | be attempted. This effectively replaces <code>gettimeofday</code> by <code>clock_get |
|
|
1545 | (CLOCK_REALTIME, ...)</code> and will not normally affect correctness. See tzhe note about libraries |
|
|
1546 | in the description of <code>EV_USE_MONOTONIC</code>, though.</p> |
|
|
1547 | </dd> |
|
|
1548 | <dt>EV_USE_SELECT</dt> |
|
|
1549 | <dd> |
|
|
1550 | <p>If undefined or defined to be <code>1</code>, libev will compile in support for the |
|
|
1551 | <code>select</code>(2) backend. No attempt at autodetection will be done: if no |
|
|
1552 | other method takes over, select will be it. Otherwise the select backend |
|
|
1553 | will not be compiled in.</p> |
|
|
1554 | </dd> |
|
|
1555 | <dt>EV_SELECT_USE_FD_SET</dt> |
|
|
1556 | <dd> |
|
|
1557 | <p>If defined to <code>1</code>, then the select backend will use the system <code>fd_set</code> |
|
|
1558 | structure. This is useful if libev doesn't compile due to a missing |
|
|
1559 | <code>NFDBITS</code> or <code>fd_mask</code> definition or it misguesses the bitset layout on |
|
|
1560 | exotic systems. This usually limits the range of file descriptors to some |
|
|
1561 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
1562 | allows 64 sockets). The <code>FD_SETSIZE</code> macro, set before compilation, might |
|
|
1563 | influence the size of the <code>fd_set</code> used.</p> |
|
|
1564 | </dd> |
|
|
1565 | <dt>EV_SELECT_IS_WINSOCKET</dt> |
|
|
1566 | <dd> |
|
|
1567 | <p>When defined to <code>1</code>, the select backend will assume that |
|
|
1568 | select/socket/connect etc. don't understand file descriptors but |
|
|
1569 | wants osf handles on win32 (this is the case when the select to |
|
|
1570 | be used is the winsock select). This means that it will call |
|
|
1571 | <code>_get_osfhandle</code> on the fd to convert it to an OS handle. Otherwise, |
|
|
1572 | it is assumed that all these functions actually work on fds, even |
|
|
1573 | on win32. Should not be defined on non-win32 platforms.</p> |
|
|
1574 | </dd> |
|
|
1575 | <dt>EV_USE_POLL</dt> |
|
|
1576 | <dd> |
|
|
1577 | <p>If defined to be <code>1</code>, libev will compile in support for the <code>poll</code>(2) |
|
|
1578 | backend. Otherwise it will be enabled on non-win32 platforms. It |
|
|
1579 | takes precedence over select.</p> |
|
|
1580 | </dd> |
|
|
1581 | <dt>EV_USE_EPOLL</dt> |
|
|
1582 | <dd> |
|
|
1583 | <p>If defined to be <code>1</code>, libev will compile in support for the Linux |
|
|
1584 | <code>epoll</code>(7) backend. Its availability will be detected at runtime, |
|
|
1585 | otherwise another method will be used as fallback. This is the |
|
|
1586 | preferred backend for GNU/Linux systems.</p> |
|
|
1587 | </dd> |
|
|
1588 | <dt>EV_USE_KQUEUE</dt> |
|
|
1589 | <dd> |
|
|
1590 | <p>If defined to be <code>1</code>, libev will compile in support for the BSD style |
|
|
1591 | <code>kqueue</code>(2) backend. Its actual availability will be detected at runtime, |
|
|
1592 | otherwise another method will be used as fallback. This is the preferred |
|
|
1593 | backend for BSD and BSD-like systems, although on most BSDs kqueue only |
|
|
1594 | supports some types of fds correctly (the only platform we found that |
|
|
1595 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
1596 | not be used unless explicitly requested. The best way to use it is to find |
|
|
1597 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
1598 | kqueue loop.</p> |
|
|
1599 | </dd> |
|
|
1600 | <dt>EV_USE_PORT</dt> |
|
|
1601 | <dd> |
|
|
1602 | <p>If defined to be <code>1</code>, libev will compile in support for the Solaris |
|
|
1603 | 10 port style backend. Its availability will be detected at runtime, |
|
|
1604 | otherwise another method will be used as fallback. This is the preferred |
|
|
1605 | backend for Solaris 10 systems.</p> |
|
|
1606 | </dd> |
|
|
1607 | <dt>EV_USE_DEVPOLL</dt> |
|
|
1608 | <dd> |
|
|
1609 | <p>reserved for future expansion, works like the USE symbols above.</p> |
|
|
1610 | </dd> |
|
|
1611 | <dt>EV_H</dt> |
|
|
1612 | <dd> |
|
|
1613 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
|
|
1614 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
|
|
1615 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
|
|
1616 | </dd> |
|
|
1617 | <dt>EV_CONFIG_H</dt> |
|
|
1618 | <dd> |
|
|
1619 | <p>If <code>EV_STANDALONE</code> isn't <code>1</code>, this variable can be used to override |
|
|
1620 | <cite>ev.c</cite>'s idea of where to find the <cite>config.h</cite> file, similarly to |
|
|
1621 | <code>EV_H</code>, above.</p> |
|
|
1622 | </dd> |
|
|
1623 | <dt>EV_EVENT_H</dt> |
|
|
1624 | <dd> |
|
|
1625 | <p>Similarly to <code>EV_H</code>, this macro can be used to override <cite>event.c</cite>'s idea |
|
|
1626 | of how the <cite>event.h</cite> header can be found.</p> |
|
|
1627 | </dd> |
|
|
1628 | <dt>EV_PROTOTYPES</dt> |
|
|
1629 | <dd> |
|
|
1630 | <p>If defined to be <code>0</code>, then <cite>ev.h</cite> will not define any function |
|
|
1631 | prototypes, but still define all the structs and other symbols. This is |
|
|
1632 | occasionally useful if you want to provide your own wrapper functions |
|
|
1633 | around libev functions.</p> |
|
|
1634 | </dd> |
|
|
1635 | <dt>EV_MULTIPLICITY</dt> |
|
|
1636 | <dd> |
|
|
1637 | <p>If undefined or defined to <code>1</code>, then all event-loop-specific functions |
|
|
1638 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
|
|
1639 | additional independent event loops. Otherwise there will be no support |
|
|
1640 | for multiple event loops and there is no first event loop pointer |
|
|
1641 | argument. Instead, all functions act on the single default loop.</p> |
|
|
1642 | </dd> |
|
|
1643 | <dt>EV_PERIODICS</dt> |
|
|
1644 | <dd> |
|
|
1645 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported, |
|
|
1646 | otherwise not. This saves a few kb of code.</p> |
|
|
1647 | </dd> |
|
|
1648 | <dt>EV_COMMON</dt> |
|
|
1649 | <dd> |
|
|
1650 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
|
|
1651 | this macro to a something else you can include more and other types of |
|
|
1652 | members. You have to define it each time you include one of the files, |
|
|
1653 | though, and it must be identical each time.</p> |
|
|
1654 | <p>For example, the perl EV module uses something like this:</p> |
|
|
1655 | <pre> #define EV_COMMON \ |
|
|
1656 | SV *self; /* contains this struct */ \ |
|
|
1657 | SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
1658 | |
|
|
1659 | </pre> |
|
|
1660 | </dd> |
|
|
1661 | <dt>EV_CB_DECLARE (type)</dt> |
|
|
1662 | <dt>EV_CB_INVOKE (watcher, revents)</dt> |
|
|
1663 | <dt>ev_set_cb (ev, cb)</dt> |
|
|
1664 | <dd> |
|
|
1665 | <p>Can be used to change the callback member declaration in each watcher, |
|
|
1666 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
1667 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
|
|
1668 | their default definitions. One possible use for overriding these is to |
|
|
1669 | avoid the <code>struct ev_loop *</code> as first argument in all cases, or to use |
|
|
1670 | method calls instead of plain function calls in C++.</p> |
|
|
1671 | |
|
|
1672 | </div> |
|
|
1673 | <h2 id="EXAMPLES">EXAMPLES</h2> |
|
|
1674 | <div id="EXAMPLES_CONTENT"> |
|
|
1675 | <p>For a real-world example of a program the includes libev |
|
|
1676 | verbatim, you can have a look at the EV perl module |
|
|
1677 | (<a href="http://software.schmorp.de/pkg/EV.html">http://software.schmorp.de/pkg/EV.html</a>). It has the libev files in |
|
|
1678 | the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public |
|
|
1679 | interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file |
|
|
1680 | will be compiled. It is pretty complex because it provides its own header |
|
|
1681 | file.</p> |
|
|
1682 | <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file |
|
|
1683 | that everybody includes and which overrides some autoconf choices:</p> |
|
|
1684 | <pre> #define EV_USE_POLL 0 |
|
|
1685 | #define EV_MULTIPLICITY 0 |
|
|
1686 | #define EV_PERIODICS 0 |
|
|
1687 | #define EV_CONFIG_H <config.h> |
|
|
1688 | |
|
|
1689 | #include "ev++.h" |
|
|
1690 | |
|
|
1691 | </pre> |
|
|
1692 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
|
|
1693 | <pre> #include "ev_cpp.h" |
|
|
1694 | #include "ev.c" |
|
|
1695 | |
|
|
1696 | </pre> |
1213 | |
1697 | |
1214 | </div> |
1698 | </div> |
1215 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1699 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1216 | <div id="AUTHOR_CONTENT"> |
1700 | <div id="AUTHOR_CONTENT"> |
1217 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
1701 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
1218 | |
1702 | |
1219 | </div> |
1703 | </div> |
1220 | </div></body> |
1704 | </div></body> |
1221 | </html> |
1705 | </html> |