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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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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> |
26 | <ul><li><a href="#SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS">SUMMARY OF GENERIC WATCHER FUNCTIONS</a></li> |
26 | <ul><li><a href="#GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</a></li> |
27 | <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> |
28 | </ul> |
28 | </ul> |
29 | </li> |
29 | </li> |
30 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
30 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
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 | <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> |
32 | <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> |
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_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</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_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a></li> |
35 | <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> |
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36 | <li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</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> |
37 | <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> |
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> |
38 | <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> |
38 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</a></li> |
39 | <li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li> |
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40 | <li><a href="#code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</a></li> |
39 | </ul> |
41 | </ul> |
40 | </li> |
42 | </li> |
41 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
43 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
42 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
44 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
43 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
45 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
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46 | <li><a href="#MACRO_MAGIC">MACRO MAGIC</a></li> |
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47 | <li><a href="#EMBEDDING">EMBEDDING</a> |
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48 | <ul><li><a href="#FILESETS">FILESETS</a> |
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49 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
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50 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
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51 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
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52 | </ul> |
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53 | </li> |
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54 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
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55 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
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56 | </ul> |
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57 | </li> |
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58 | <li><a href="#COMPLEXITIES">COMPLEXITIES</a></li> |
44 | <li><a href="#AUTHOR">AUTHOR</a> |
59 | <li><a href="#AUTHOR">AUTHOR</a> |
45 | </li> |
60 | </li> |
46 | </ul><hr /> |
61 | </ul><hr /> |
47 | <!-- INDEX END --> |
62 | <!-- INDEX END --> |
48 | |
63 | |
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100 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
115 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
101 | the beginning of 1970, details are complicated, don't ask). This type is |
116 | the beginning of 1970, details are complicated, don't ask). This type is |
102 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
117 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
103 | to the <code>double</code> type in C, and when you need to do any calculations on |
118 | to the <code>double</code> type in C, and when you need to do any calculations on |
104 | it, you should treat it as such.</p> |
119 | it, you should treat it as such.</p> |
105 | |
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106 | |
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107 | |
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108 | |
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109 | |
120 | |
110 | </div> |
121 | </div> |
111 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
122 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
112 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
123 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
113 | <p>These functions can be called anytime, even before initialising the |
124 | <p>These functions can be called anytime, even before initialising the |
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168 | might be supported on the current system, you would need to look at |
179 | might be supported on the current system, you would need to look at |
169 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
180 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
170 | recommended ones.</p> |
181 | recommended ones.</p> |
171 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
182 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
172 | </dd> |
183 | </dd> |
173 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
184 | <dt>ev_set_allocator (void *(*cb)(void *ptr, size_t size))</dt> |
174 | <dd> |
185 | <dd> |
175 | <p>Sets the allocation function to use (the prototype is similar to the |
186 | <p>Sets the allocation function to use (the prototype and semantics are |
176 | realloc C function, the semantics are identical). It is used to allocate |
187 | identical to the realloc C function). It is used to allocate and free |
177 | and free memory (no surprises here). If it returns zero when memory |
188 | memory (no surprises here). If it returns zero when memory needs to be |
178 | needs to be allocated, the library might abort or take some potentially |
189 | allocated, the library might abort or take some potentially destructive |
179 | destructive action. The default is your system realloc function.</p> |
190 | action. The default is your system realloc function.</p> |
180 | <p>You could override this function in high-availability programs to, say, |
191 | <p>You could override this function in high-availability programs to, say, |
181 | free some memory if it cannot allocate memory, to use a special allocator, |
192 | free some memory if it cannot allocate memory, to use a special allocator, |
182 | or even to sleep a while and retry until some memory is available.</p> |
193 | or even to sleep a while and retry until some memory is available.</p> |
183 | <p>Example: replace the libev allocator with one that waits a bit and then |
194 | <p>Example: replace the libev allocator with one that waits a bit and then |
184 | retries: better than mine).</p> |
195 | retries: better than mine).</p> |
185 | <pre> static void * |
196 | <pre> static void * |
186 | persistent_realloc (void *ptr, long size) |
197 | persistent_realloc (void *ptr, size_t size) |
187 | { |
198 | { |
188 | for (;;) |
199 | for (;;) |
189 | { |
200 | { |
190 | void *newptr = realloc (ptr, size); |
201 | void *newptr = realloc (ptr, size); |
191 | |
202 | |
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502 | |
513 | |
503 | </pre> |
514 | </pre> |
504 | </dd> |
515 | </dd> |
505 | </dl> |
516 | </dl> |
506 | |
517 | |
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518 | |
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519 | |
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520 | |
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521 | |
507 | </div> |
522 | </div> |
508 | <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> |
509 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
524 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
510 | <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 |
511 | 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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570 | </dd> |
585 | </dd> |
571 | <dt><code>EV_CHILD</code></dt> |
586 | <dt><code>EV_CHILD</code></dt> |
572 | <dd> |
587 | <dd> |
573 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
588 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
574 | </dd> |
589 | </dd> |
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590 | <dt><code>EV_STAT</code></dt> |
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591 | <dd> |
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592 | <p>The path specified in the <code>ev_stat</code> watcher changed its attributes somehow.</p> |
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593 | </dd> |
575 | <dt><code>EV_IDLE</code></dt> |
594 | <dt><code>EV_IDLE</code></dt> |
576 | <dd> |
595 | <dd> |
577 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
596 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
578 | </dd> |
597 | </dd> |
579 | <dt><code>EV_PREPARE</code></dt> |
598 | <dt><code>EV_PREPARE</code></dt> |
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584 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
603 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
585 | received events. Callbacks of both watcher types can start and stop as |
604 | received events. Callbacks of both watcher types can start and stop as |
586 | many watchers as they want, and all of them will be taken into account |
605 | many watchers as they want, and all of them will be taken into account |
587 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
606 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
588 | <code>ev_loop</code> from blocking).</p> |
607 | <code>ev_loop</code> from blocking).</p> |
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608 | </dd> |
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609 | <dt><code>EV_EMBED</code></dt> |
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610 | <dd> |
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611 | <p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p> |
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612 | </dd> |
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613 | <dt><code>EV_FORK</code></dt> |
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614 | <dd> |
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615 | <p>The event loop has been resumed in the child process after fork (see |
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616 | <code>ev_fork</code>).</p> |
589 | </dd> |
617 | </dd> |
590 | <dt><code>EV_ERROR</code></dt> |
618 | <dt><code>EV_ERROR</code></dt> |
591 | <dd> |
619 | <dd> |
592 | <p>An unspecified error has occured, the watcher has been stopped. This might |
620 | <p>An unspecified error has occured, the watcher has been stopped. This might |
593 | happen because the watcher could not be properly started because libev |
621 | happen because the watcher could not be properly started because libev |
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601 | programs, though, so beware.</p> |
629 | programs, though, so beware.</p> |
602 | </dd> |
630 | </dd> |
603 | </dl> |
631 | </dl> |
604 | |
632 | |
605 | </div> |
633 | </div> |
606 | <h2 id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS">SUMMARY OF GENERIC WATCHER FUNCTIONS</h2> |
634 | <h2 id="GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</h2> |
607 | <div id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS-2"> |
635 | <div id="GENERIC_WATCHER_FUNCTIONS_CONTENT"> |
608 | <p>In the following description, <code>TYPE</code> stands for the watcher type, |
636 | <p>In the following description, <code>TYPE</code> stands for the watcher type, |
609 | e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p> |
637 | e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p> |
610 | <dl> |
638 | <dl> |
611 | <dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt> |
639 | <dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt> |
612 | <dd> |
640 | <dd> |
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616 | the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the |
644 | the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the |
617 | type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro |
645 | type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro |
618 | which rolls both calls into one.</p> |
646 | which rolls both calls into one.</p> |
619 | <p>You can reinitialise a watcher at any time as long as it has been stopped |
647 | <p>You can reinitialise a watcher at any time as long as it has been stopped |
620 | (or never started) and there are no pending events outstanding.</p> |
648 | (or never started) and there are no pending events outstanding.</p> |
621 | <p>The callbakc is always of type <code>void (*)(ev_loop *loop, ev_TYPE *watcher, |
649 | <p>The callback is always of type <code>void (*)(ev_loop *loop, ev_TYPE *watcher, |
622 | int revents)</code>.</p> |
650 | int revents)</code>.</p> |
623 | </dd> |
651 | </dd> |
624 | <dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt> |
652 | <dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt> |
625 | <dd> |
653 | <dd> |
626 | <p>This macro initialises the type-specific parts of a watcher. You need to |
654 | <p>This macro initialises the type-specific parts of a watcher. You need to |
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716 | |
744 | |
717 | </div> |
745 | </div> |
718 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
746 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
719 | <div id="WATCHER_TYPES_CONTENT"> |
747 | <div id="WATCHER_TYPES_CONTENT"> |
720 | <p>This section describes each watcher in detail, but will not repeat |
748 | <p>This section describes each watcher in detail, but will not repeat |
721 | information given in the last section.</p> |
749 | information given in the last section. Any initialisation/set macros, |
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750 | functions and members specific to the watcher type are explained.</p> |
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751 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
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752 | while the watcher is active, you can look at the member and expect some |
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753 | sensible content, but you must not modify it (you can modify it while the |
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754 | watcher is stopped to your hearts content), or <i>[read-write]</i>, which |
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755 | means you can expect it to have some sensible content while the watcher |
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756 | is active, but you can also modify it. Modifying it may not do something |
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757 | sensible or take immediate effect (or do anything at all), but libev will |
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758 | not crash or malfunction in any way.</p> |
722 | |
759 | |
723 | |
760 | |
724 | |
761 | |
725 | |
762 | |
726 | |
763 | |
727 | </div> |
764 | </div> |
728 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2> |
765 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</h2> |
729 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
766 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
730 | <p>I/O watchers check whether a file descriptor is readable or writable |
767 | <p>I/O watchers check whether a file descriptor is readable or writable |
731 | in each iteration of the event loop (This behaviour is called |
768 | in each iteration of the event loop, or, more precisely, when reading |
732 | level-triggering because you keep receiving events as long as the |
769 | would not block the process and writing would at least be able to write |
733 | condition persists. Remember you can stop the watcher if you don't want to |
770 | some data. This behaviour is called level-triggering because you keep |
734 | act on the event and neither want to receive future events).</p> |
771 | receiving events as long as the condition persists. Remember you can stop |
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772 | the watcher if you don't want to act on the event and neither want to |
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773 | receive future events.</p> |
735 | <p>In general you can register as many read and/or write event watchers per |
774 | <p>In general you can register as many read and/or write event watchers per |
736 | fd as you want (as long as you don't confuse yourself). Setting all file |
775 | fd as you want (as long as you don't confuse yourself). Setting all file |
737 | descriptors to non-blocking mode is also usually a good idea (but not |
776 | descriptors to non-blocking mode is also usually a good idea (but not |
738 | required if you know what you are doing).</p> |
777 | required if you know what you are doing).</p> |
739 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
778 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
740 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
779 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
741 | descriptors correctly if you register interest in two or more fds pointing |
780 | descriptors correctly if you register interest in two or more fds pointing |
742 | to the same underlying file/socket etc. description (that is, they share |
781 | to the same underlying file/socket/etc. description (that is, they share |
743 | the same underlying "file open").</p> |
782 | the same underlying "file open").</p> |
744 | <p>If you must do this, then force the use of a known-to-be-good backend |
783 | <p>If you must do this, then force the use of a known-to-be-good backend |
745 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
784 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
746 | <code>EVBACKEND_POLL</code>).</p> |
785 | <code>EVBACKEND_POLL</code>).</p> |
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786 | <p>Another thing you have to watch out for is that it is quite easy to |
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787 | receive "spurious" readyness notifications, that is your callback might |
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788 | be called with <code>EV_READ</code> but a subsequent <code>read</code>(2) will actually block |
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789 | because there is no data. Not only are some backends known to create a |
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790 | lot of those (for example solaris ports), it is very easy to get into |
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791 | this situation even with a relatively standard program structure. Thus |
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792 | it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning |
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793 | <code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p> |
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794 | <p>If you cannot run the fd in non-blocking mode (for example you should not |
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795 | play around with an Xlib connection), then you have to seperately re-test |
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796 | wether a file descriptor is really ready with a known-to-be good interface |
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797 | such as poll (fortunately in our Xlib example, Xlib already does this on |
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798 | its own, so its quite safe to use).</p> |
747 | <dl> |
799 | <dl> |
748 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
800 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
749 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
801 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
750 | <dd> |
802 | <dd> |
751 | <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive |
803 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
752 | events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ | |
804 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
753 | EV_WRITE</code> to receive the given events.</p> |
805 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
754 | <p>Please note that most of the more scalable backend mechanisms (for example |
806 | </dd> |
755 | epoll and solaris ports) can result in spurious readyness notifications |
807 | <dt>int fd [read-only]</dt> |
756 | for file descriptors, so you practically need to use non-blocking I/O (and |
808 | <dd> |
757 | treat callback invocation as hint only), or retest separately with a safe |
809 | <p>The file descriptor being watched.</p> |
758 | interface before doing I/O (XLib can do this), or force the use of either |
810 | </dd> |
759 | <code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this |
811 | <dt>int events [read-only]</dt> |
760 | problem. Also note that it is quite easy to have your callback invoked |
812 | <dd> |
761 | when the readyness condition is no longer valid even when employing |
813 | <p>The events being watched.</p> |
762 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
763 | I/O unconditionally.</p> |
|
|
764 | </dd> |
814 | </dd> |
765 | </dl> |
815 | </dl> |
766 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
816 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
767 | readable, but only once. Since it is likely line-buffered, you could |
817 | readable, but only once. Since it is likely line-buffered, you could |
768 | attempt to read a whole line in the callback:</p> |
818 | attempt to read a whole line in the callback:</p> |
… | |
… | |
784 | |
834 | |
785 | |
835 | |
786 | </pre> |
836 | </pre> |
787 | |
837 | |
788 | </div> |
838 | </div> |
789 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2> |
839 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</h2> |
790 | <div id="code_ev_timer_code_relative_and_opti-2"> |
840 | <div id="code_ev_timer_code_relative_and_opti-2"> |
791 | <p>Timer watchers are simple relative timers that generate an event after a |
841 | <p>Timer watchers are simple relative timers that generate an event after a |
792 | given time, and optionally repeating in regular intervals after that.</p> |
842 | given time, and optionally repeating in regular intervals after that.</p> |
793 | <p>The timers are based on real time, that is, if you register an event that |
843 | <p>The timers are based on real time, that is, if you register an event that |
794 | times out after an hour and you reset your system clock to last years |
844 | times out after an hour and you reset your system clock to last years |
… | |
… | |
826 | repeating. The exact semantics are:</p> |
876 | repeating. The exact semantics are:</p> |
827 | <p>If the timer is started but nonrepeating, stop it.</p> |
877 | <p>If the timer is started but nonrepeating, stop it.</p> |
828 | <p>If the timer is repeating, either start it if necessary (with the repeat |
878 | <p>If the timer is repeating, either start it if necessary (with the repeat |
829 | value), or reset the running timer to the repeat value.</p> |
879 | value), or reset the running timer to the repeat value.</p> |
830 | <p>This sounds a bit complicated, but here is a useful and typical |
880 | <p>This sounds a bit complicated, but here is a useful and typical |
831 | example: Imagine you have a tcp connection and you want a so-called idle |
881 | example: Imagine you have a tcp connection and you want a so-called |
832 | timeout, that is, you want to be called when there have been, say, 60 |
882 | idle timeout, that is, you want to be called when there have been, |
833 | seconds of inactivity on the socket. The easiest way to do this is to |
883 | say, 60 seconds of inactivity on the socket. The easiest way to do |
834 | configure an <code>ev_timer</code> with after=repeat=60 and calling ev_timer_again each |
884 | this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling |
835 | time you successfully read or write some data. If you go into an idle |
885 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
836 | state where you do not expect data to travel on the socket, you can stop |
886 | you go into an idle state where you do not expect data to travel on the |
837 | the timer, and again will automatically restart it if need be.</p> |
887 | socket, you can stop the timer, and again will automatically restart it if |
|
|
888 | need be.</p> |
|
|
889 | <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether |
|
|
890 | and only ever use the <code>repeat</code> value:</p> |
|
|
891 | <pre> ev_timer_init (timer, callback, 0., 5.); |
|
|
892 | ev_timer_again (loop, timer); |
|
|
893 | ... |
|
|
894 | timer->again = 17.; |
|
|
895 | ev_timer_again (loop, timer); |
|
|
896 | ... |
|
|
897 | timer->again = 10.; |
|
|
898 | ev_timer_again (loop, timer); |
|
|
899 | |
|
|
900 | </pre> |
|
|
901 | <p>This is more efficient then stopping/starting the timer eahc time you want |
|
|
902 | to modify its timeout value.</p> |
|
|
903 | </dd> |
|
|
904 | <dt>ev_tstamp repeat [read-write]</dt> |
|
|
905 | <dd> |
|
|
906 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
|
|
907 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
|
|
908 | which is also when any modifications are taken into account.</p> |
838 | </dd> |
909 | </dd> |
839 | </dl> |
910 | </dl> |
840 | <p>Example: create a timer that fires after 60 seconds.</p> |
911 | <p>Example: create a timer that fires after 60 seconds.</p> |
841 | <pre> static void |
912 | <pre> static void |
842 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
913 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
… | |
… | |
870 | |
941 | |
871 | |
942 | |
872 | </pre> |
943 | </pre> |
873 | |
944 | |
874 | </div> |
945 | </div> |
875 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2> |
946 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</h2> |
876 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
947 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
877 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
948 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
878 | (and unfortunately a bit complex).</p> |
949 | (and unfortunately a bit complex).</p> |
879 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
950 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
880 | but on wallclock time (absolute time). You can tell a periodic watcher |
951 | but on wallclock time (absolute time). You can tell a periodic watcher |
… | |
… | |
960 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
1031 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
961 | when you changed some parameters or the reschedule callback would return |
1032 | when you changed some parameters or the reschedule callback would return |
962 | a different time than the last time it was called (e.g. in a crond like |
1033 | a different time than the last time it was called (e.g. in a crond like |
963 | program when the crontabs have changed).</p> |
1034 | program when the crontabs have changed).</p> |
964 | </dd> |
1035 | </dd> |
|
|
1036 | <dt>ev_tstamp interval [read-write]</dt> |
|
|
1037 | <dd> |
|
|
1038 | <p>The current interval value. Can be modified any time, but changes only |
|
|
1039 | take effect when the periodic timer fires or <code>ev_periodic_again</code> is being |
|
|
1040 | called.</p> |
|
|
1041 | </dd> |
|
|
1042 | <dt>ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]</dt> |
|
|
1043 | <dd> |
|
|
1044 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
|
|
1045 | switched off. Can be changed any time, but changes only take effect when |
|
|
1046 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
|
|
1047 | </dd> |
965 | </dl> |
1048 | </dl> |
966 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1049 | <p>Example: call a callback every hour, or, more precisely, whenever the |
967 | system clock is divisible by 3600. The callback invocation times have |
1050 | system clock is divisible by 3600. The callback invocation times have |
968 | potentially a lot of jittering, but good long-term stability.</p> |
1051 | potentially a lot of jittering, but good long-term stability.</p> |
969 | <pre> static void |
1052 | <pre> static void |
… | |
… | |
999 | |
1082 | |
1000 | |
1083 | |
1001 | </pre> |
1084 | </pre> |
1002 | |
1085 | |
1003 | </div> |
1086 | </div> |
1004 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2> |
1087 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</h2> |
1005 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
1088 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
1006 | <p>Signal watchers will trigger an event when the process receives a specific |
1089 | <p>Signal watchers will trigger an event when the process receives a specific |
1007 | signal one or more times. Even though signals are very asynchronous, libev |
1090 | signal one or more times. Even though signals are very asynchronous, libev |
1008 | will try it's best to deliver signals synchronously, i.e. as part of the |
1091 | will try it's best to deliver signals synchronously, i.e. as part of the |
1009 | normal event processing, like any other event.</p> |
1092 | normal event processing, like any other event.</p> |
… | |
… | |
1018 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1101 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1019 | <dd> |
1102 | <dd> |
1020 | <p>Configures the watcher to trigger on the given signal number (usually one |
1103 | <p>Configures the watcher to trigger on the given signal number (usually one |
1021 | of the <code>SIGxxx</code> constants).</p> |
1104 | of the <code>SIGxxx</code> constants).</p> |
1022 | </dd> |
1105 | </dd> |
|
|
1106 | <dt>int signum [read-only]</dt> |
|
|
1107 | <dd> |
|
|
1108 | <p>The signal the watcher watches out for.</p> |
|
|
1109 | </dd> |
1023 | </dl> |
1110 | </dl> |
1024 | |
1111 | |
1025 | |
1112 | |
1026 | |
1113 | |
1027 | |
1114 | |
1028 | |
1115 | |
1029 | </div> |
1116 | </div> |
1030 | <h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2> |
1117 | <h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2> |
1031 | <div id="code_ev_child_code_wait_for_pid_stat-2"> |
1118 | <div id="code_ev_child_code_watch_out_for_pro-2"> |
1032 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
1119 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
1033 | some child status changes (most typically when a child of yours dies).</p> |
1120 | some child status changes (most typically when a child of yours dies).</p> |
1034 | <dl> |
1121 | <dl> |
1035 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
1122 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
1036 | <dt>ev_child_set (ev_child *, int pid)</dt> |
1123 | <dt>ev_child_set (ev_child *, int pid)</dt> |
… | |
… | |
1039 | <i>any</i> process if <code>pid</code> is specified as <code>0</code>). The callback can look |
1126 | <i>any</i> process if <code>pid</code> is specified as <code>0</code>). The callback can look |
1040 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1127 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1041 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1128 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1042 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1129 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1043 | process causing the status change.</p> |
1130 | process causing the status change.</p> |
|
|
1131 | </dd> |
|
|
1132 | <dt>int pid [read-only]</dt> |
|
|
1133 | <dd> |
|
|
1134 | <p>The process id this watcher watches out for, or <code>0</code>, meaning any process id.</p> |
|
|
1135 | </dd> |
|
|
1136 | <dt>int rpid [read-write]</dt> |
|
|
1137 | <dd> |
|
|
1138 | <p>The process id that detected a status change.</p> |
|
|
1139 | </dd> |
|
|
1140 | <dt>int rstatus [read-write]</dt> |
|
|
1141 | <dd> |
|
|
1142 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
|
|
1143 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
1044 | </dd> |
1144 | </dd> |
1045 | </dl> |
1145 | </dl> |
1046 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1146 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1047 | <pre> static void |
1147 | <pre> static void |
1048 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1148 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
… | |
… | |
1058 | |
1158 | |
1059 | |
1159 | |
1060 | </pre> |
1160 | </pre> |
1061 | |
1161 | |
1062 | </div> |
1162 | </div> |
|
|
1163 | <h2 id="code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</h2> |
|
|
1164 | <div id="code_ev_stat_code_did_the_file_attri-2"> |
|
|
1165 | <p>This watches a filesystem path for attribute changes. That is, it calls |
|
|
1166 | <code>stat</code> regularly (or when the OS says it changed) and sees if it changed |
|
|
1167 | compared to the last time, invoking the callback if it did.</p> |
|
|
1168 | <p>The path does not need to exist: changing from "path exists" to "path does |
|
|
1169 | not exist" is a status change like any other. The condition "path does |
|
|
1170 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
|
|
1171 | otherwise always forced to be at least one) and all the other fields of |
|
|
1172 | the stat buffer having unspecified contents.</p> |
|
|
1173 | <p>Since there is no standard to do this, the portable implementation simply |
|
|
1174 | calls <code>stat (2)</code> regulalry on the path to see if it changed somehow. You |
|
|
1175 | can specify a recommended polling interval for this case. If you specify |
|
|
1176 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
|
|
1177 | unspecified default</i> value will be used (which you can expect to be around |
|
|
1178 | five seconds, although this might change dynamically). Libev will also |
|
|
1179 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
|
|
1180 | usually overkill.</p> |
|
|
1181 | <p>This watcher type is not meant for massive numbers of stat watchers, |
|
|
1182 | as even with OS-supported change notifications, this can be |
|
|
1183 | resource-intensive.</p> |
|
|
1184 | <p>At the time of this writing, no specific OS backends are implemented, but |
|
|
1185 | if demand increases, at least a kqueue and inotify backend will be added.</p> |
|
|
1186 | <dl> |
|
|
1187 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
|
|
1188 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
|
|
1189 | <dd> |
|
|
1190 | <p>Configures the watcher to wait for status changes of the given |
|
|
1191 | <code>path</code>. The <code>interval</code> is a hint on how quickly a change is expected to |
|
|
1192 | be detected and should normally be specified as <code>0</code> to let libev choose |
|
|
1193 | a suitable value. The memory pointed to by <code>path</code> must point to the same |
|
|
1194 | path for as long as the watcher is active.</p> |
|
|
1195 | <p>The callback will be receive <code>EV_STAT</code> when a change was detected, |
|
|
1196 | relative to the attributes at the time the watcher was started (or the |
|
|
1197 | last change was detected).</p> |
|
|
1198 | </dd> |
|
|
1199 | <dt>ev_stat_stat (ev_stat *)</dt> |
|
|
1200 | <dd> |
|
|
1201 | <p>Updates the stat buffer immediately with new values. If you change the |
|
|
1202 | watched path in your callback, you could call this fucntion to avoid |
|
|
1203 | detecting this change (while introducing a race condition). Can also be |
|
|
1204 | useful simply to find out the new values.</p> |
|
|
1205 | </dd> |
|
|
1206 | <dt>ev_statdata attr [read-only]</dt> |
|
|
1207 | <dd> |
|
|
1208 | <p>The most-recently detected attributes of the file. Although the type is of |
|
|
1209 | <code>ev_statdata</code>, this is usually the (or one of the) <code>struct stat</code> types |
|
|
1210 | suitable for your system. If the <code>st_nlink</code> member is <code>0</code>, then there |
|
|
1211 | was some error while <code>stat</code>ing the file.</p> |
|
|
1212 | </dd> |
|
|
1213 | <dt>ev_statdata prev [read-only]</dt> |
|
|
1214 | <dd> |
|
|
1215 | <p>The previous attributes of the file. The callback gets invoked whenever |
|
|
1216 | <code>prev</code> != <code>attr</code>.</p> |
|
|
1217 | </dd> |
|
|
1218 | <dt>ev_tstamp interval [read-only]</dt> |
|
|
1219 | <dd> |
|
|
1220 | <p>The specified interval.</p> |
|
|
1221 | </dd> |
|
|
1222 | <dt>const char *path [read-only]</dt> |
|
|
1223 | <dd> |
|
|
1224 | <p>The filesystem path that is being watched.</p> |
|
|
1225 | </dd> |
|
|
1226 | </dl> |
|
|
1227 | <p>Example: Watch <code>/etc/passwd</code> for attribute changes.</p> |
|
|
1228 | <pre> static void |
|
|
1229 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1230 | { |
|
|
1231 | /* /etc/passwd changed in some way */ |
|
|
1232 | if (w->attr.st_nlink) |
|
|
1233 | { |
|
|
1234 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1235 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1236 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1237 | } |
|
|
1238 | else |
|
|
1239 | /* you shalt not abuse printf for puts */ |
|
|
1240 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1241 | "if this is windows, they already arrived\n"); |
|
|
1242 | } |
|
|
1243 | |
|
|
1244 | ... |
|
|
1245 | ev_stat passwd; |
|
|
1246 | |
|
|
1247 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1248 | ev_stat_start (loop, &passwd); |
|
|
1249 | |
|
|
1250 | |
|
|
1251 | |
|
|
1252 | |
|
|
1253 | </pre> |
|
|
1254 | |
|
|
1255 | </div> |
1063 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2> |
1256 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2> |
1064 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1257 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1065 | <p>Idle watchers trigger events when there are no other events are pending |
1258 | <p>Idle watchers trigger events when there are no other events are pending |
1066 | (prepare, check and other idle watchers do not count). That is, as long |
1259 | (prepare, check and other idle watchers do not count). That is, as long |
1067 | as your process is busy handling sockets or timeouts (or even signals, |
1260 | as your process is busy handling sockets or timeouts (or even signals, |
1068 | imagine) it will not be triggered. But when your process is idle all idle |
1261 | imagine) it will not be triggered. But when your process is idle all idle |
… | |
… | |
1101 | |
1294 | |
1102 | |
1295 | |
1103 | </pre> |
1296 | </pre> |
1104 | |
1297 | |
1105 | </div> |
1298 | </div> |
1106 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2> |
1299 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2> |
1107 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1300 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1108 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1301 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1109 | prepare watchers get invoked before the process blocks and check watchers |
1302 | prepare watchers get invoked before the process blocks and check watchers |
1110 | afterwards.</p> |
1303 | afterwards.</p> |
|
|
1304 | <p>You <i>must not</i> call <code>ev_loop</code> or similar functions that enter |
|
|
1305 | the current event loop from either <code>ev_prepare</code> or <code>ev_check</code> |
|
|
1306 | watchers. Other loops than the current one are fine, however. The |
|
|
1307 | rationale behind this is that you do not need to check for recursion in |
|
|
1308 | those watchers, i.e. the sequence will always be <code>ev_prepare</code>, blocking, |
|
|
1309 | <code>ev_check</code> so if you have one watcher of each kind they will always be |
|
|
1310 | called in pairs bracketing the blocking call.</p> |
1111 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1311 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1112 | their use is somewhat advanced. This could be used, for example, to track |
1312 | their use is somewhat advanced. This could be used, for example, to track |
1113 | variable changes, implement your own watchers, integrate net-snmp or a |
1313 | variable changes, implement your own watchers, integrate net-snmp or a |
1114 | coroutine library and lots more.</p> |
1314 | coroutine library and lots more. They are also occasionally useful if |
|
|
1315 | you cache some data and want to flush it before blocking (for example, |
|
|
1316 | in X programs you might want to do an <code>XFlush ()</code> in an <code>ev_prepare</code> |
|
|
1317 | watcher).</p> |
1115 | <p>This is done by examining in each prepare call which file descriptors need |
1318 | <p>This is done by examining in each prepare call which file descriptors need |
1116 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1319 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1117 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1320 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1118 | provide just this functionality). Then, in the check watcher you check for |
1321 | provide just this functionality). Then, in the check watcher you check for |
1119 | any events that occured (by checking the pending status of all watchers |
1322 | any events that occured (by checking the pending status of all watchers |
… | |
… | |
1135 | <p>Initialises and configures the prepare or check watcher - they have no |
1338 | <p>Initialises and configures the prepare or check watcher - they have no |
1136 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1339 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1137 | macros, but using them is utterly, utterly and completely pointless.</p> |
1340 | macros, but using them is utterly, utterly and completely pointless.</p> |
1138 | </dd> |
1341 | </dd> |
1139 | </dl> |
1342 | </dl> |
1140 | <p>Example: *TODO*.</p> |
1343 | <p>Example: To include a library such as adns, you would add IO watchers |
|
|
1344 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1345 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1346 | pseudo-code only of course:</p> |
|
|
1347 | <pre> static ev_io iow [nfd]; |
|
|
1348 | static ev_timer tw; |
1141 | |
1349 | |
|
|
1350 | static void |
|
|
1351 | io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1352 | { |
|
|
1353 | // set the relevant poll flags |
|
|
1354 | // could also call adns_processreadable etc. here |
|
|
1355 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1356 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1357 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1358 | } |
1142 | |
1359 | |
|
|
1360 | // create io watchers for each fd and a timer before blocking |
|
|
1361 | static void |
|
|
1362 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1363 | { |
|
|
1364 | int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1365 | // actual code will need to loop here and realloc etc. |
|
|
1366 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1143 | |
1367 | |
|
|
1368 | /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1369 | ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1370 | ev_timer_start (loop, &tw); |
1144 | |
1371 | |
|
|
1372 | // create on ev_io per pollfd |
|
|
1373 | for (int i = 0; i < nfd; ++i) |
|
|
1374 | { |
|
|
1375 | ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1376 | ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1377 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1145 | |
1378 | |
|
|
1379 | fds [i].revents = 0; |
|
|
1380 | iow [i].data = fds + i; |
|
|
1381 | ev_io_start (loop, iow + i); |
|
|
1382 | } |
|
|
1383 | } |
|
|
1384 | |
|
|
1385 | // stop all watchers after blocking |
|
|
1386 | static void |
|
|
1387 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1388 | { |
|
|
1389 | ev_timer_stop (loop, &tw); |
|
|
1390 | |
|
|
1391 | for (int i = 0; i < nfd; ++i) |
|
|
1392 | ev_io_stop (loop, iow + i); |
|
|
1393 | |
|
|
1394 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1395 | } |
|
|
1396 | |
|
|
1397 | |
|
|
1398 | |
|
|
1399 | |
|
|
1400 | </pre> |
|
|
1401 | |
1146 | </div> |
1402 | </div> |
1147 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</h2> |
1403 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1148 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1404 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1149 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1405 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1150 | into another (currently only <code>ev_io</code> events are supported in the embedded |
1406 | into another (currently only <code>ev_io</code> events are supported in the embedded |
1151 | loop, other types of watchers might be handled in a delayed or incorrect |
1407 | loop, other types of watchers might be handled in a delayed or incorrect |
1152 | fashion and must not be used).</p> |
1408 | fashion and must not be used).</p> |
… | |
… | |
1219 | <dt>ev_embed_sweep (loop, ev_embed *)</dt> |
1475 | <dt>ev_embed_sweep (loop, ev_embed *)</dt> |
1220 | <dd> |
1476 | <dd> |
1221 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1477 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1222 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1478 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1223 | apropriate way for embedded loops.</p> |
1479 | apropriate way for embedded loops.</p> |
|
|
1480 | </dd> |
|
|
1481 | <dt>struct ev_loop *loop [read-only]</dt> |
|
|
1482 | <dd> |
|
|
1483 | <p>The embedded event loop.</p> |
|
|
1484 | </dd> |
|
|
1485 | </dl> |
|
|
1486 | |
|
|
1487 | |
|
|
1488 | |
|
|
1489 | |
|
|
1490 | |
|
|
1491 | </div> |
|
|
1492 | <h2 id="code_ev_fork_code_the_audacity_to_re"><code>ev_fork</code> - the audacity to resume the event loop after a fork</h2> |
|
|
1493 | <div id="code_ev_fork_code_the_audacity_to_re-2"> |
|
|
1494 | <p>Fork watchers are called when a <code>fork ()</code> was detected (usually because |
|
|
1495 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1496 | <code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the |
|
|
1497 | event loop blocks next and before <code>ev_check</code> watchers are being called, |
|
|
1498 | and only in the child after the fork. If whoever good citizen calling |
|
|
1499 | <code>ev_default_fork</code> cheats and calls it in the wrong process, the fork |
|
|
1500 | handlers will be invoked, too, of course.</p> |
|
|
1501 | <dl> |
|
|
1502 | <dt>ev_fork_init (ev_signal *, callback)</dt> |
|
|
1503 | <dd> |
|
|
1504 | <p>Initialises and configures the fork watcher - it has no parameters of any |
|
|
1505 | kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless, |
|
|
1506 | believe me.</p> |
1224 | </dd> |
1507 | </dd> |
1225 | </dl> |
1508 | </dl> |
1226 | |
1509 | |
1227 | |
1510 | |
1228 | |
1511 | |
… | |
… | |
1378 | </dd> |
1661 | </dd> |
1379 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1662 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1380 | <dd> |
1663 | <dd> |
1381 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1664 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1382 | </dd> |
1665 | </dd> |
|
|
1666 | <dt>w->update () <code>ev::stat</code> only</dt> |
|
|
1667 | <dd> |
|
|
1668 | <p>Invokes <code>ev_stat_stat</code>.</p> |
|
|
1669 | </dd> |
1383 | </dl> |
1670 | </dl> |
1384 | </p> |
1671 | </p> |
1385 | </dd> |
1672 | </dd> |
1386 | </dl> |
1673 | </dl> |
1387 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
1674 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1399 | idle (this, &myclass::idle_cb) |
1686 | idle (this, &myclass::idle_cb) |
1400 | { |
1687 | { |
1401 | io.start (fd, ev::READ); |
1688 | io.start (fd, ev::READ); |
1402 | } |
1689 | } |
1403 | |
1690 | |
|
|
1691 | |
|
|
1692 | |
|
|
1693 | |
1404 | </pre> |
1694 | </pre> |
|
|
1695 | |
|
|
1696 | </div> |
|
|
1697 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> |
|
|
1698 | <div id="MACRO_MAGIC_CONTENT"> |
|
|
1699 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1700 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
|
|
1701 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
|
|
1702 | <p>To make it easier to write programs that cope with either variant, the |
|
|
1703 | following macros are defined:</p> |
|
|
1704 | <dl> |
|
|
1705 | <dt><code>EV_A</code>, <code>EV_A_</code></dt> |
|
|
1706 | <dd> |
|
|
1707 | <p>This provides the loop <i>argument</i> for functions, if one is required ("ev |
|
|
1708 | loop argument"). The <code>EV_A</code> form is used when this is the sole argument, |
|
|
1709 | <code>EV_A_</code> is used when other arguments are following. Example:</p> |
|
|
1710 | <pre> ev_unref (EV_A); |
|
|
1711 | ev_timer_add (EV_A_ watcher); |
|
|
1712 | ev_loop (EV_A_ 0); |
|
|
1713 | |
|
|
1714 | </pre> |
|
|
1715 | <p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope, |
|
|
1716 | which is often provided by the following macro.</p> |
|
|
1717 | </dd> |
|
|
1718 | <dt><code>EV_P</code>, <code>EV_P_</code></dt> |
|
|
1719 | <dd> |
|
|
1720 | <p>This provides the loop <i>parameter</i> for functions, if one is required ("ev |
|
|
1721 | loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter, |
|
|
1722 | <code>EV_P_</code> is used when other parameters are following. Example:</p> |
|
|
1723 | <pre> // this is how ev_unref is being declared |
|
|
1724 | static void ev_unref (EV_P); |
|
|
1725 | |
|
|
1726 | // this is how you can declare your typical callback |
|
|
1727 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1728 | |
|
|
1729 | </pre> |
|
|
1730 | <p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite |
|
|
1731 | suitable for use with <code>EV_A</code>.</p> |
|
|
1732 | </dd> |
|
|
1733 | <dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt> |
|
|
1734 | <dd> |
|
|
1735 | <p>Similar to the other two macros, this gives you the value of the default |
|
|
1736 | loop, if multiple loops are supported ("ev loop default").</p> |
|
|
1737 | </dd> |
|
|
1738 | </dl> |
|
|
1739 | <p>Example: Declare and initialise a check watcher, working regardless of |
|
|
1740 | wether multiple loops are supported or not.</p> |
|
|
1741 | <pre> static void |
|
|
1742 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1743 | { |
|
|
1744 | ev_check_stop (EV_A_ w); |
|
|
1745 | } |
|
|
1746 | |
|
|
1747 | ev_check check; |
|
|
1748 | ev_check_init (&check, check_cb); |
|
|
1749 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1750 | ev_loop (EV_DEFAULT_ 0); |
|
|
1751 | |
|
|
1752 | |
|
|
1753 | |
|
|
1754 | |
|
|
1755 | </pre> |
|
|
1756 | |
|
|
1757 | </div> |
|
|
1758 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
|
|
1759 | <div id="EMBEDDING_CONTENT"> |
|
|
1760 | <p>Libev can (and often is) directly embedded into host |
|
|
1761 | applications. Examples of applications that embed it include the Deliantra |
|
|
1762 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
|
|
1763 | and rxvt-unicode.</p> |
|
|
1764 | <p>The goal is to enable you to just copy the neecssary files into your |
|
|
1765 | source directory without having to change even a single line in them, so |
|
|
1766 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
1767 | libev somewhere in your source tree).</p> |
|
|
1768 | |
|
|
1769 | </div> |
|
|
1770 | <h2 id="FILESETS">FILESETS</h2> |
|
|
1771 | <div id="FILESETS_CONTENT"> |
|
|
1772 | <p>Depending on what features you need you need to include one or more sets of files |
|
|
1773 | in your app.</p> |
|
|
1774 | |
|
|
1775 | </div> |
|
|
1776 | <h3 id="CORE_EVENT_LOOP">CORE EVENT LOOP</h3> |
|
|
1777 | <div id="CORE_EVENT_LOOP_CONTENT"> |
|
|
1778 | <p>To include only the libev core (all the <code>ev_*</code> functions), with manual |
|
|
1779 | configuration (no autoconf):</p> |
|
|
1780 | <pre> #define EV_STANDALONE 1 |
|
|
1781 | #include "ev.c" |
|
|
1782 | |
|
|
1783 | </pre> |
|
|
1784 | <p>This will automatically include <cite>ev.h</cite>, too, and should be done in a |
|
|
1785 | single C source file only to provide the function implementations. To use |
|
|
1786 | it, do the same for <cite>ev.h</cite> in all files wishing to use this API (best |
|
|
1787 | done by writing a wrapper around <cite>ev.h</cite> that you can include instead and |
|
|
1788 | where you can put other configuration options):</p> |
|
|
1789 | <pre> #define EV_STANDALONE 1 |
|
|
1790 | #include "ev.h" |
|
|
1791 | |
|
|
1792 | </pre> |
|
|
1793 | <p>Both header files and implementation files can be compiled with a C++ |
|
|
1794 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
1795 | as a bug).</p> |
|
|
1796 | <p>You need the following files in your source tree, or in a directory |
|
|
1797 | in your include path (e.g. in libev/ when using -Ilibev):</p> |
|
|
1798 | <pre> ev.h |
|
|
1799 | ev.c |
|
|
1800 | ev_vars.h |
|
|
1801 | ev_wrap.h |
|
|
1802 | |
|
|
1803 | ev_win32.c required on win32 platforms only |
|
|
1804 | |
|
|
1805 | ev_select.c only when select backend is enabled (which is by default) |
|
|
1806 | ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
1807 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
1808 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
1809 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
1810 | |
|
|
1811 | </pre> |
|
|
1812 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
|
|
1813 | to compile this single file.</p> |
|
|
1814 | |
|
|
1815 | </div> |
|
|
1816 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
|
|
1817 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
|
|
1818 | <p>To include the libevent compatibility API, also include:</p> |
|
|
1819 | <pre> #include "event.c" |
|
|
1820 | |
|
|
1821 | </pre> |
|
|
1822 | <p>in the file including <cite>ev.c</cite>, and:</p> |
|
|
1823 | <pre> #include "event.h" |
|
|
1824 | |
|
|
1825 | </pre> |
|
|
1826 | <p>in the files that want to use the libevent API. This also includes <cite>ev.h</cite>.</p> |
|
|
1827 | <p>You need the following additional files for this:</p> |
|
|
1828 | <pre> event.h |
|
|
1829 | event.c |
|
|
1830 | |
|
|
1831 | </pre> |
|
|
1832 | |
|
|
1833 | </div> |
|
|
1834 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
|
|
1835 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
|
|
1836 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
|
|
1837 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
|
|
1838 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> undefined. <cite>ev.c</cite> will then |
|
|
1839 | include <cite>config.h</cite> and configure itself accordingly.</p> |
|
|
1840 | <p>For this of course you need the m4 file:</p> |
|
|
1841 | <pre> libev.m4 |
|
|
1842 | |
|
|
1843 | </pre> |
|
|
1844 | |
|
|
1845 | </div> |
|
|
1846 | <h2 id="PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</h2> |
|
|
1847 | <div id="PREPROCESSOR_SYMBOLS_MACROS_CONTENT"> |
|
|
1848 | <p>Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
1849 | before including any of its files. The default is not to build for multiplicity |
|
|
1850 | and only include the select backend.</p> |
|
|
1851 | <dl> |
|
|
1852 | <dt>EV_STANDALONE</dt> |
|
|
1853 | <dd> |
|
|
1854 | <p>Must always be <code>1</code> if you do not use autoconf configuration, which |
|
|
1855 | keeps libev from including <cite>config.h</cite>, and it also defines dummy |
|
|
1856 | implementations for some libevent functions (such as logging, which is not |
|
|
1857 | supported). It will also not define any of the structs usually found in |
|
|
1858 | <cite>event.h</cite> that are not directly supported by the libev core alone.</p> |
|
|
1859 | </dd> |
|
|
1860 | <dt>EV_USE_MONOTONIC</dt> |
|
|
1861 | <dd> |
|
|
1862 | <p>If defined to be <code>1</code>, libev will try to detect the availability of the |
|
|
1863 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
1864 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
1865 | usually have to link against librt or something similar. Enabling it when |
|
|
1866 | the functionality isn't available is safe, though, althoguh you have |
|
|
1867 | to make sure you link against any libraries where the <code>clock_gettime</code> |
|
|
1868 | function is hiding in (often <cite>-lrt</cite>).</p> |
|
|
1869 | </dd> |
|
|
1870 | <dt>EV_USE_REALTIME</dt> |
|
|
1871 | <dd> |
|
|
1872 | <p>If defined to be <code>1</code>, libev will try to detect the availability of the |
|
|
1873 | realtime clock option at compiletime (and assume its availability at |
|
|
1874 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
1875 | be attempted. This effectively replaces <code>gettimeofday</code> by <code>clock_get |
|
|
1876 | (CLOCK_REALTIME, ...)</code> and will not normally affect correctness. See tzhe note about libraries |
|
|
1877 | in the description of <code>EV_USE_MONOTONIC</code>, though.</p> |
|
|
1878 | </dd> |
|
|
1879 | <dt>EV_USE_SELECT</dt> |
|
|
1880 | <dd> |
|
|
1881 | <p>If undefined or defined to be <code>1</code>, libev will compile in support for the |
|
|
1882 | <code>select</code>(2) backend. No attempt at autodetection will be done: if no |
|
|
1883 | other method takes over, select will be it. Otherwise the select backend |
|
|
1884 | will not be compiled in.</p> |
|
|
1885 | </dd> |
|
|
1886 | <dt>EV_SELECT_USE_FD_SET</dt> |
|
|
1887 | <dd> |
|
|
1888 | <p>If defined to <code>1</code>, then the select backend will use the system <code>fd_set</code> |
|
|
1889 | structure. This is useful if libev doesn't compile due to a missing |
|
|
1890 | <code>NFDBITS</code> or <code>fd_mask</code> definition or it misguesses the bitset layout on |
|
|
1891 | exotic systems. This usually limits the range of file descriptors to some |
|
|
1892 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
1893 | allows 64 sockets). The <code>FD_SETSIZE</code> macro, set before compilation, might |
|
|
1894 | influence the size of the <code>fd_set</code> used.</p> |
|
|
1895 | </dd> |
|
|
1896 | <dt>EV_SELECT_IS_WINSOCKET</dt> |
|
|
1897 | <dd> |
|
|
1898 | <p>When defined to <code>1</code>, the select backend will assume that |
|
|
1899 | select/socket/connect etc. don't understand file descriptors but |
|
|
1900 | wants osf handles on win32 (this is the case when the select to |
|
|
1901 | be used is the winsock select). This means that it will call |
|
|
1902 | <code>_get_osfhandle</code> on the fd to convert it to an OS handle. Otherwise, |
|
|
1903 | it is assumed that all these functions actually work on fds, even |
|
|
1904 | on win32. Should not be defined on non-win32 platforms.</p> |
|
|
1905 | </dd> |
|
|
1906 | <dt>EV_USE_POLL</dt> |
|
|
1907 | <dd> |
|
|
1908 | <p>If defined to be <code>1</code>, libev will compile in support for the <code>poll</code>(2) |
|
|
1909 | backend. Otherwise it will be enabled on non-win32 platforms. It |
|
|
1910 | takes precedence over select.</p> |
|
|
1911 | </dd> |
|
|
1912 | <dt>EV_USE_EPOLL</dt> |
|
|
1913 | <dd> |
|
|
1914 | <p>If defined to be <code>1</code>, libev will compile in support for the Linux |
|
|
1915 | <code>epoll</code>(7) backend. Its availability will be detected at runtime, |
|
|
1916 | otherwise another method will be used as fallback. This is the |
|
|
1917 | preferred backend for GNU/Linux systems.</p> |
|
|
1918 | </dd> |
|
|
1919 | <dt>EV_USE_KQUEUE</dt> |
|
|
1920 | <dd> |
|
|
1921 | <p>If defined to be <code>1</code>, libev will compile in support for the BSD style |
|
|
1922 | <code>kqueue</code>(2) backend. Its actual availability will be detected at runtime, |
|
|
1923 | otherwise another method will be used as fallback. This is the preferred |
|
|
1924 | backend for BSD and BSD-like systems, although on most BSDs kqueue only |
|
|
1925 | supports some types of fds correctly (the only platform we found that |
|
|
1926 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
1927 | not be used unless explicitly requested. The best way to use it is to find |
|
|
1928 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
1929 | kqueue loop.</p> |
|
|
1930 | </dd> |
|
|
1931 | <dt>EV_USE_PORT</dt> |
|
|
1932 | <dd> |
|
|
1933 | <p>If defined to be <code>1</code>, libev will compile in support for the Solaris |
|
|
1934 | 10 port style backend. Its availability will be detected at runtime, |
|
|
1935 | otherwise another method will be used as fallback. This is the preferred |
|
|
1936 | backend for Solaris 10 systems.</p> |
|
|
1937 | </dd> |
|
|
1938 | <dt>EV_USE_DEVPOLL</dt> |
|
|
1939 | <dd> |
|
|
1940 | <p>reserved for future expansion, works like the USE symbols above.</p> |
|
|
1941 | </dd> |
|
|
1942 | <dt>EV_H</dt> |
|
|
1943 | <dd> |
|
|
1944 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
|
|
1945 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
|
|
1946 | can be used to virtually rename the <cite>ev.h</cite> header file in case of conflicts.</p> |
|
|
1947 | </dd> |
|
|
1948 | <dt>EV_CONFIG_H</dt> |
|
|
1949 | <dd> |
|
|
1950 | <p>If <code>EV_STANDALONE</code> isn't <code>1</code>, this variable can be used to override |
|
|
1951 | <cite>ev.c</cite>'s idea of where to find the <cite>config.h</cite> file, similarly to |
|
|
1952 | <code>EV_H</code>, above.</p> |
|
|
1953 | </dd> |
|
|
1954 | <dt>EV_EVENT_H</dt> |
|
|
1955 | <dd> |
|
|
1956 | <p>Similarly to <code>EV_H</code>, this macro can be used to override <cite>event.c</cite>'s idea |
|
|
1957 | of how the <cite>event.h</cite> header can be found.</p> |
|
|
1958 | </dd> |
|
|
1959 | <dt>EV_PROTOTYPES</dt> |
|
|
1960 | <dd> |
|
|
1961 | <p>If defined to be <code>0</code>, then <cite>ev.h</cite> will not define any function |
|
|
1962 | prototypes, but still define all the structs and other symbols. This is |
|
|
1963 | occasionally useful if you want to provide your own wrapper functions |
|
|
1964 | around libev functions.</p> |
|
|
1965 | </dd> |
|
|
1966 | <dt>EV_MULTIPLICITY</dt> |
|
|
1967 | <dd> |
|
|
1968 | <p>If undefined or defined to <code>1</code>, then all event-loop-specific functions |
|
|
1969 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
|
|
1970 | additional independent event loops. Otherwise there will be no support |
|
|
1971 | for multiple event loops and there is no first event loop pointer |
|
|
1972 | argument. Instead, all functions act on the single default loop.</p> |
|
|
1973 | </dd> |
|
|
1974 | <dt>EV_PERIODIC_ENABLE</dt> |
|
|
1975 | <dd> |
|
|
1976 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If |
|
|
1977 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
|
|
1978 | code.</p> |
|
|
1979 | </dd> |
|
|
1980 | <dt>EV_EMBED_ENABLE</dt> |
|
|
1981 | <dd> |
|
|
1982 | <p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If |
|
|
1983 | defined to be <code>0</code>, then they are not.</p> |
|
|
1984 | </dd> |
|
|
1985 | <dt>EV_STAT_ENABLE</dt> |
|
|
1986 | <dd> |
|
|
1987 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
|
|
1988 | defined to be <code>0</code>, then they are not.</p> |
|
|
1989 | </dd> |
|
|
1990 | <dt>EV_FORK_ENABLE</dt> |
|
|
1991 | <dd> |
|
|
1992 | <p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If |
|
|
1993 | defined to be <code>0</code>, then they are not.</p> |
|
|
1994 | </dd> |
|
|
1995 | <dt>EV_MINIMAL</dt> |
|
|
1996 | <dd> |
|
|
1997 | <p>If you need to shave off some kilobytes of code at the expense of some |
|
|
1998 | speed, define this symbol to <code>1</code>. Currently only used for gcc to override |
|
|
1999 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
|
|
2000 | </dd> |
|
|
2001 | <dt>EV_PID_HASHSIZE</dt> |
|
|
2002 | <dd> |
|
|
2003 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
|
|
2004 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
|
|
2005 | than enough. If you need to manage thousands of children you might want to |
|
|
2006 | increase this value.</p> |
|
|
2007 | </dd> |
|
|
2008 | <dt>EV_COMMON</dt> |
|
|
2009 | <dd> |
|
|
2010 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
|
|
2011 | this macro to a something else you can include more and other types of |
|
|
2012 | members. You have to define it each time you include one of the files, |
|
|
2013 | though, and it must be identical each time.</p> |
|
|
2014 | <p>For example, the perl EV module uses something like this:</p> |
|
|
2015 | <pre> #define EV_COMMON \ |
|
|
2016 | SV *self; /* contains this struct */ \ |
|
|
2017 | SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
2018 | |
|
|
2019 | </pre> |
|
|
2020 | </dd> |
|
|
2021 | <dt>EV_CB_DECLARE (type)</dt> |
|
|
2022 | <dt>EV_CB_INVOKE (watcher, revents)</dt> |
|
|
2023 | <dt>ev_set_cb (ev, cb)</dt> |
|
|
2024 | <dd> |
|
|
2025 | <p>Can be used to change the callback member declaration in each watcher, |
|
|
2026 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
2027 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
|
|
2028 | their default definitions. One possible use for overriding these is to |
|
|
2029 | avoid the <code>struct ev_loop *</code> as first argument in all cases, or to use |
|
|
2030 | method calls instead of plain function calls in C++.</p> |
|
|
2031 | |
|
|
2032 | </div> |
|
|
2033 | <h2 id="EXAMPLES">EXAMPLES</h2> |
|
|
2034 | <div id="EXAMPLES_CONTENT"> |
|
|
2035 | <p>For a real-world example of a program the includes libev |
|
|
2036 | verbatim, you can have a look at the EV perl module |
|
|
2037 | (<a href="http://software.schmorp.de/pkg/EV.html">http://software.schmorp.de/pkg/EV.html</a>). It has the libev files in |
|
|
2038 | the <cite>libev/</cite> subdirectory and includes them in the <cite>EV/EVAPI.h</cite> (public |
|
|
2039 | interface) and <cite>EV.xs</cite> (implementation) files. Only the <cite>EV.xs</cite> file |
|
|
2040 | will be compiled. It is pretty complex because it provides its own header |
|
|
2041 | file.</p> |
|
|
2042 | <p>The usage in rxvt-unicode is simpler. It has a <cite>ev_cpp.h</cite> header file |
|
|
2043 | that everybody includes and which overrides some autoconf choices:</p> |
|
|
2044 | <pre> #define EV_USE_POLL 0 |
|
|
2045 | #define EV_MULTIPLICITY 0 |
|
|
2046 | #define EV_PERIODICS 0 |
|
|
2047 | #define EV_CONFIG_H <config.h> |
|
|
2048 | |
|
|
2049 | #include "ev++.h" |
|
|
2050 | |
|
|
2051 | </pre> |
|
|
2052 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
|
|
2053 | <pre> #include "ev_cpp.h" |
|
|
2054 | #include "ev.c" |
|
|
2055 | |
|
|
2056 | |
|
|
2057 | |
|
|
2058 | |
|
|
2059 | </pre> |
|
|
2060 | |
|
|
2061 | </div> |
|
|
2062 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
|
|
2063 | <div id="COMPLEXITIES_CONTENT"> |
|
|
2064 | <p>In this section the complexities of (many of) the algorithms used inside |
|
|
2065 | libev will be explained. For complexity discussions about backends see the |
|
|
2066 | documentation for <code>ev_default_init</code>.</p> |
|
|
2067 | <p> |
|
|
2068 | <dl> |
|
|
2069 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
|
|
2070 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
|
|
2071 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
|
|
2072 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
|
|
2073 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))</dt> |
|
|
2074 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
|
|
2075 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
|
|
2076 | <dt>Activating one watcher: O(1)</dt> |
|
|
2077 | </dl> |
|
|
2078 | </p> |
|
|
2079 | |
|
|
2080 | |
|
|
2081 | |
|
|
2082 | |
1405 | |
2083 | |
1406 | </div> |
2084 | </div> |
1407 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2085 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1408 | <div id="AUTHOR_CONTENT"> |
2086 | <div id="AUTHOR_CONTENT"> |
1409 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2087 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
1410 | |
2088 | |
1411 | </div> |
2089 | </div> |
1412 | </div></body> |
2090 | </div></body> |
1413 | </html> |
2091 | </html> |