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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" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
7 | <meta name="inputfile" content="<standard input>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
8 | <meta name="outputfile" content="<standard output>" /> |
9 | <meta name="created" content="Sat Nov 24 17:57:37 2007" /> |
9 | <meta name="created" content="Tue Nov 27 21:14:27 2007" /> |
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12 | <body> |
12 | <body> |
13 | <div class="pod"> |
13 | <div class="pod"> |
14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
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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 repeating 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_watch_out_for_pro"><code>ev_child</code> - watch out for process 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> |
44 | <li><a href="#EMBEDDING">EMBEDDING</a> |
47 | <li><a href="#EMBEDDING">EMBEDDING</a> |
45 | <ul><li><a href="#FILESETS">FILESETS</a> |
48 | <ul><li><a href="#FILESETS">FILESETS</a> |
46 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
49 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
47 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
50 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
48 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
51 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
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50 | </li> |
53 | </li> |
51 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
54 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
52 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
55 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
53 | </ul> |
56 | </ul> |
54 | </li> |
57 | </li> |
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58 | <li><a href="#COMPLEXITIES">COMPLEXITIES</a></li> |
55 | <li><a href="#AUTHOR">AUTHOR</a> |
59 | <li><a href="#AUTHOR">AUTHOR</a> |
56 | </li> |
60 | </li> |
57 | </ul><hr /> |
61 | </ul><hr /> |
58 | <!-- INDEX END --> |
62 | <!-- INDEX END --> |
59 | |
63 | |
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62 | <p>libev - a high performance full-featured event loop written in C</p> |
66 | <p>libev - a high performance full-featured event loop written in C</p> |
63 | |
67 | |
64 | </div> |
68 | </div> |
65 | <h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
69 | <h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
66 | <div id="SYNOPSIS_CONTENT"> |
70 | <div id="SYNOPSIS_CONTENT"> |
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71 | <pre> /* this is the only header you need */ |
67 | <pre> #include <ev.h> |
72 | #include <ev.h> |
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73 | |
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74 | /* what follows is a fully working example program */ |
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75 | ev_io stdin_watcher; |
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76 | ev_timer timeout_watcher; |
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77 | |
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78 | /* called when data readable on stdin */ |
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79 | static void |
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80 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
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81 | { |
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82 | /* puts ("stdin ready"); */ |
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83 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
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84 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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85 | } |
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86 | |
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87 | static void |
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88 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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89 | { |
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90 | /* puts ("timeout"); */ |
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91 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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92 | } |
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93 | |
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94 | int |
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95 | main (void) |
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96 | { |
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97 | struct ev_loop *loop = ev_default_loop (0); |
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98 | |
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99 | /* initialise an io watcher, then start it */ |
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100 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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101 | ev_io_start (loop, &stdin_watcher); |
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102 | |
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103 | /* simple non-repeating 5.5 second timeout */ |
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104 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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105 | ev_timer_start (loop, &timeout_watcher); |
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106 | |
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107 | /* loop till timeout or data ready */ |
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108 | ev_loop (loop, 0); |
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109 | |
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110 | return 0; |
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111 | } |
68 | |
112 | |
69 | </pre> |
113 | </pre> |
70 | |
114 | |
71 | </div> |
115 | </div> |
72 | <h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
116 | <h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
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111 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
155 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
112 | the beginning of 1970, details are complicated, don't ask). This type is |
156 | the beginning of 1970, details are complicated, don't ask). This type is |
113 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
157 | called <code>ev_tstamp</code>, which is what you should use too. It usually aliases |
114 | to the <code>double</code> type in C, and when you need to do any calculations on |
158 | to the <code>double</code> type in C, and when you need to do any calculations on |
115 | it, you should treat it as such.</p> |
159 | it, you should treat it as such.</p> |
116 | |
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117 | |
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118 | |
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119 | |
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120 | |
160 | |
121 | </div> |
161 | </div> |
122 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
162 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
123 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
163 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
124 | <p>These functions can be called anytime, even before initialising the |
164 | <p>These functions can be called anytime, even before initialising the |
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179 | might be supported on the current system, you would need to look at |
219 | might be supported on the current system, you would need to look at |
180 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
220 | <code>ev_embeddable_backends () & ev_supported_backends ()</code>, likewise for |
181 | recommended ones.</p> |
221 | recommended ones.</p> |
182 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
222 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
183 | </dd> |
223 | </dd> |
184 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
224 | <dt>ev_set_allocator (void *(*cb)(void *ptr, size_t size))</dt> |
185 | <dd> |
225 | <dd> |
186 | <p>Sets the allocation function to use (the prototype is similar to the |
226 | <p>Sets the allocation function to use (the prototype and semantics are |
187 | realloc C function, the semantics are identical). It is used to allocate |
227 | identical to the realloc C function). It is used to allocate and free |
188 | and free memory (no surprises here). If it returns zero when memory |
228 | memory (no surprises here). If it returns zero when memory needs to be |
189 | needs to be allocated, the library might abort or take some potentially |
229 | allocated, the library might abort or take some potentially destructive |
190 | destructive action. The default is your system realloc function.</p> |
230 | action. The default is your system realloc function.</p> |
191 | <p>You could override this function in high-availability programs to, say, |
231 | <p>You could override this function in high-availability programs to, say, |
192 | free some memory if it cannot allocate memory, to use a special allocator, |
232 | free some memory if it cannot allocate memory, to use a special allocator, |
193 | or even to sleep a while and retry until some memory is available.</p> |
233 | or even to sleep a while and retry until some memory is available.</p> |
194 | <p>Example: replace the libev allocator with one that waits a bit and then |
234 | <p>Example: replace the libev allocator with one that waits a bit and then |
195 | retries: better than mine).</p> |
235 | retries: better than mine).</p> |
196 | <pre> static void * |
236 | <pre> static void * |
197 | persistent_realloc (void *ptr, long size) |
237 | persistent_realloc (void *ptr, size_t size) |
198 | { |
238 | { |
199 | for (;;) |
239 | for (;;) |
200 | { |
240 | { |
201 | void *newptr = realloc (ptr, size); |
241 | void *newptr = realloc (ptr, size); |
202 | |
242 | |
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585 | </dd> |
625 | </dd> |
586 | <dt><code>EV_CHILD</code></dt> |
626 | <dt><code>EV_CHILD</code></dt> |
587 | <dd> |
627 | <dd> |
588 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
628 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
589 | </dd> |
629 | </dd> |
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630 | <dt><code>EV_STAT</code></dt> |
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631 | <dd> |
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632 | <p>The path specified in the <code>ev_stat</code> watcher changed its attributes somehow.</p> |
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633 | </dd> |
590 | <dt><code>EV_IDLE</code></dt> |
634 | <dt><code>EV_IDLE</code></dt> |
591 | <dd> |
635 | <dd> |
592 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
636 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
593 | </dd> |
637 | </dd> |
594 | <dt><code>EV_PREPARE</code></dt> |
638 | <dt><code>EV_PREPARE</code></dt> |
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599 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
643 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
600 | received events. Callbacks of both watcher types can start and stop as |
644 | received events. Callbacks of both watcher types can start and stop as |
601 | many watchers as they want, and all of them will be taken into account |
645 | many watchers as they want, and all of them will be taken into account |
602 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
646 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
603 | <code>ev_loop</code> from blocking).</p> |
647 | <code>ev_loop</code> from blocking).</p> |
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648 | </dd> |
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649 | <dt><code>EV_EMBED</code></dt> |
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650 | <dd> |
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651 | <p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p> |
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652 | </dd> |
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653 | <dt><code>EV_FORK</code></dt> |
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654 | <dd> |
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655 | <p>The event loop has been resumed in the child process after fork (see |
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656 | <code>ev_fork</code>).</p> |
604 | </dd> |
657 | </dd> |
605 | <dt><code>EV_ERROR</code></dt> |
658 | <dt><code>EV_ERROR</code></dt> |
606 | <dd> |
659 | <dd> |
607 | <p>An unspecified error has occured, the watcher has been stopped. This might |
660 | <p>An unspecified error has occured, the watcher has been stopped. This might |
608 | happen because the watcher could not be properly started because libev |
661 | happen because the watcher could not be properly started because libev |
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731 | |
784 | |
732 | </div> |
785 | </div> |
733 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
786 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
734 | <div id="WATCHER_TYPES_CONTENT"> |
787 | <div id="WATCHER_TYPES_CONTENT"> |
735 | <p>This section describes each watcher in detail, but will not repeat |
788 | <p>This section describes each watcher in detail, but will not repeat |
736 | information given in the last section.</p> |
789 | information given in the last section. Any initialisation/set macros, |
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790 | functions and members specific to the watcher type are explained.</p> |
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791 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
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792 | while the watcher is active, you can look at the member and expect some |
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793 | sensible content, but you must not modify it (you can modify it while the |
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794 | watcher is stopped to your hearts content), or <i>[read-write]</i>, which |
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795 | means you can expect it to have some sensible content while the watcher |
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796 | is active, but you can also modify it. Modifying it may not do something |
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797 | sensible or take immediate effect (or do anything at all), but libev will |
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798 | not crash or malfunction in any way.</p> |
737 | |
799 | |
738 | |
800 | |
739 | |
801 | |
740 | |
802 | |
741 | |
803 | |
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780 | <dd> |
842 | <dd> |
781 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
843 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
782 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
844 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
783 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
845 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
784 | </dd> |
846 | </dd> |
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847 | <dt>int fd [read-only]</dt> |
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848 | <dd> |
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849 | <p>The file descriptor being watched.</p> |
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850 | </dd> |
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851 | <dt>int events [read-only]</dt> |
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852 | <dd> |
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853 | <p>The events being watched.</p> |
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854 | </dd> |
785 | </dl> |
855 | </dl> |
786 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
856 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
787 | readable, but only once. Since it is likely line-buffered, you could |
857 | readable, but only once. Since it is likely line-buffered, you could |
788 | attempt to read a whole line in the callback:</p> |
858 | attempt to read a whole line in the callback:</p> |
789 | <pre> static void |
859 | <pre> static void |
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846 | repeating. The exact semantics are:</p> |
916 | repeating. The exact semantics are:</p> |
847 | <p>If the timer is started but nonrepeating, stop it.</p> |
917 | <p>If the timer is started but nonrepeating, stop it.</p> |
848 | <p>If the timer is repeating, either start it if necessary (with the repeat |
918 | <p>If the timer is repeating, either start it if necessary (with the repeat |
849 | value), or reset the running timer to the repeat value.</p> |
919 | value), or reset the running timer to the repeat value.</p> |
850 | <p>This sounds a bit complicated, but here is a useful and typical |
920 | <p>This sounds a bit complicated, but here is a useful and typical |
851 | example: Imagine you have a tcp connection and you want a so-called idle |
921 | example: Imagine you have a tcp connection and you want a so-called |
852 | timeout, that is, you want to be called when there have been, say, 60 |
922 | idle timeout, that is, you want to be called when there have been, |
853 | seconds of inactivity on the socket. The easiest way to do this is to |
923 | say, 60 seconds of inactivity on the socket. The easiest way to do |
854 | configure an <code>ev_timer</code> with after=repeat=60 and calling ev_timer_again each |
924 | this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling |
855 | time you successfully read or write some data. If you go into an idle |
925 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
856 | state where you do not expect data to travel on the socket, you can stop |
926 | you go into an idle state where you do not expect data to travel on the |
857 | the timer, and again will automatically restart it if need be.</p> |
927 | socket, you can stop the timer, and again will automatically restart it if |
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928 | need be.</p> |
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929 | <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether |
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930 | and only ever use the <code>repeat</code> value:</p> |
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931 | <pre> ev_timer_init (timer, callback, 0., 5.); |
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932 | ev_timer_again (loop, timer); |
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933 | ... |
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934 | timer->again = 17.; |
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935 | ev_timer_again (loop, timer); |
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936 | ... |
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937 | timer->again = 10.; |
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938 | ev_timer_again (loop, timer); |
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939 | |
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940 | </pre> |
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941 | <p>This is more efficient then stopping/starting the timer eahc time you want |
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942 | to modify its timeout value.</p> |
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943 | </dd> |
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944 | <dt>ev_tstamp repeat [read-write]</dt> |
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945 | <dd> |
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946 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
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947 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
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948 | which is also when any modifications are taken into account.</p> |
858 | </dd> |
949 | </dd> |
859 | </dl> |
950 | </dl> |
860 | <p>Example: create a timer that fires after 60 seconds.</p> |
951 | <p>Example: create a timer that fires after 60 seconds.</p> |
861 | <pre> static void |
952 | <pre> static void |
862 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
953 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
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980 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
1071 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
981 | when you changed some parameters or the reschedule callback would return |
1072 | when you changed some parameters or the reschedule callback would return |
982 | a different time than the last time it was called (e.g. in a crond like |
1073 | a different time than the last time it was called (e.g. in a crond like |
983 | program when the crontabs have changed).</p> |
1074 | program when the crontabs have changed).</p> |
984 | </dd> |
1075 | </dd> |
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1076 | <dt>ev_tstamp interval [read-write]</dt> |
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1077 | <dd> |
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1078 | <p>The current interval value. Can be modified any time, but changes only |
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1079 | take effect when the periodic timer fires or <code>ev_periodic_again</code> is being |
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1080 | called.</p> |
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1081 | </dd> |
|
|
1082 | <dt>ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]</dt> |
|
|
1083 | <dd> |
|
|
1084 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
|
|
1085 | switched off. Can be changed any time, but changes only take effect when |
|
|
1086 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
|
|
1087 | </dd> |
985 | </dl> |
1088 | </dl> |
986 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1089 | <p>Example: call a callback every hour, or, more precisely, whenever the |
987 | system clock is divisible by 3600. The callback invocation times have |
1090 | system clock is divisible by 3600. The callback invocation times have |
988 | potentially a lot of jittering, but good long-term stability.</p> |
1091 | potentially a lot of jittering, but good long-term stability.</p> |
989 | <pre> static void |
1092 | <pre> static void |
… | |
… | |
1038 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1141 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1039 | <dd> |
1142 | <dd> |
1040 | <p>Configures the watcher to trigger on the given signal number (usually one |
1143 | <p>Configures the watcher to trigger on the given signal number (usually one |
1041 | of the <code>SIGxxx</code> constants).</p> |
1144 | of the <code>SIGxxx</code> constants).</p> |
1042 | </dd> |
1145 | </dd> |
|
|
1146 | <dt>int signum [read-only]</dt> |
|
|
1147 | <dd> |
|
|
1148 | <p>The signal the watcher watches out for.</p> |
|
|
1149 | </dd> |
1043 | </dl> |
1150 | </dl> |
1044 | |
1151 | |
1045 | |
1152 | |
1046 | |
1153 | |
1047 | |
1154 | |
… | |
… | |
1060 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1167 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1061 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1168 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1062 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1169 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1063 | process causing the status change.</p> |
1170 | process causing the status change.</p> |
1064 | </dd> |
1171 | </dd> |
|
|
1172 | <dt>int pid [read-only]</dt> |
|
|
1173 | <dd> |
|
|
1174 | <p>The process id this watcher watches out for, or <code>0</code>, meaning any process id.</p> |
|
|
1175 | </dd> |
|
|
1176 | <dt>int rpid [read-write]</dt> |
|
|
1177 | <dd> |
|
|
1178 | <p>The process id that detected a status change.</p> |
|
|
1179 | </dd> |
|
|
1180 | <dt>int rstatus [read-write]</dt> |
|
|
1181 | <dd> |
|
|
1182 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
|
|
1183 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
|
|
1184 | </dd> |
1065 | </dl> |
1185 | </dl> |
1066 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1186 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1067 | <pre> static void |
1187 | <pre> static void |
1068 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1188 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1069 | { |
1189 | { |
… | |
… | |
1071 | } |
1191 | } |
1072 | |
1192 | |
1073 | struct ev_signal signal_watcher; |
1193 | struct ev_signal signal_watcher; |
1074 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1194 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1075 | ev_signal_start (loop, &sigint_cb); |
1195 | ev_signal_start (loop, &sigint_cb); |
|
|
1196 | |
|
|
1197 | |
|
|
1198 | |
|
|
1199 | |
|
|
1200 | </pre> |
|
|
1201 | |
|
|
1202 | </div> |
|
|
1203 | <h2 id="code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</h2> |
|
|
1204 | <div id="code_ev_stat_code_did_the_file_attri-2"> |
|
|
1205 | <p>This watches a filesystem path for attribute changes. That is, it calls |
|
|
1206 | <code>stat</code> regularly (or when the OS says it changed) and sees if it changed |
|
|
1207 | compared to the last time, invoking the callback if it did.</p> |
|
|
1208 | <p>The path does not need to exist: changing from "path exists" to "path does |
|
|
1209 | not exist" is a status change like any other. The condition "path does |
|
|
1210 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
|
|
1211 | otherwise always forced to be at least one) and all the other fields of |
|
|
1212 | the stat buffer having unspecified contents.</p> |
|
|
1213 | <p>Since there is no standard to do this, the portable implementation simply |
|
|
1214 | calls <code>stat (2)</code> regulalry on the path to see if it changed somehow. You |
|
|
1215 | can specify a recommended polling interval for this case. If you specify |
|
|
1216 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
|
|
1217 | unspecified default</i> value will be used (which you can expect to be around |
|
|
1218 | five seconds, although this might change dynamically). Libev will also |
|
|
1219 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
|
|
1220 | usually overkill.</p> |
|
|
1221 | <p>This watcher type is not meant for massive numbers of stat watchers, |
|
|
1222 | as even with OS-supported change notifications, this can be |
|
|
1223 | resource-intensive.</p> |
|
|
1224 | <p>At the time of this writing, no specific OS backends are implemented, but |
|
|
1225 | if demand increases, at least a kqueue and inotify backend will be added.</p> |
|
|
1226 | <dl> |
|
|
1227 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
|
|
1228 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
|
|
1229 | <dd> |
|
|
1230 | <p>Configures the watcher to wait for status changes of the given |
|
|
1231 | <code>path</code>. The <code>interval</code> is a hint on how quickly a change is expected to |
|
|
1232 | be detected and should normally be specified as <code>0</code> to let libev choose |
|
|
1233 | a suitable value. The memory pointed to by <code>path</code> must point to the same |
|
|
1234 | path for as long as the watcher is active.</p> |
|
|
1235 | <p>The callback will be receive <code>EV_STAT</code> when a change was detected, |
|
|
1236 | relative to the attributes at the time the watcher was started (or the |
|
|
1237 | last change was detected).</p> |
|
|
1238 | </dd> |
|
|
1239 | <dt>ev_stat_stat (ev_stat *)</dt> |
|
|
1240 | <dd> |
|
|
1241 | <p>Updates the stat buffer immediately with new values. If you change the |
|
|
1242 | watched path in your callback, you could call this fucntion to avoid |
|
|
1243 | detecting this change (while introducing a race condition). Can also be |
|
|
1244 | useful simply to find out the new values.</p> |
|
|
1245 | </dd> |
|
|
1246 | <dt>ev_statdata attr [read-only]</dt> |
|
|
1247 | <dd> |
|
|
1248 | <p>The most-recently detected attributes of the file. Although the type is of |
|
|
1249 | <code>ev_statdata</code>, this is usually the (or one of the) <code>struct stat</code> types |
|
|
1250 | suitable for your system. If the <code>st_nlink</code> member is <code>0</code>, then there |
|
|
1251 | was some error while <code>stat</code>ing the file.</p> |
|
|
1252 | </dd> |
|
|
1253 | <dt>ev_statdata prev [read-only]</dt> |
|
|
1254 | <dd> |
|
|
1255 | <p>The previous attributes of the file. The callback gets invoked whenever |
|
|
1256 | <code>prev</code> != <code>attr</code>.</p> |
|
|
1257 | </dd> |
|
|
1258 | <dt>ev_tstamp interval [read-only]</dt> |
|
|
1259 | <dd> |
|
|
1260 | <p>The specified interval.</p> |
|
|
1261 | </dd> |
|
|
1262 | <dt>const char *path [read-only]</dt> |
|
|
1263 | <dd> |
|
|
1264 | <p>The filesystem path that is being watched.</p> |
|
|
1265 | </dd> |
|
|
1266 | </dl> |
|
|
1267 | <p>Example: Watch <code>/etc/passwd</code> for attribute changes.</p> |
|
|
1268 | <pre> static void |
|
|
1269 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1270 | { |
|
|
1271 | /* /etc/passwd changed in some way */ |
|
|
1272 | if (w->attr.st_nlink) |
|
|
1273 | { |
|
|
1274 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1275 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1276 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1277 | } |
|
|
1278 | else |
|
|
1279 | /* you shalt not abuse printf for puts */ |
|
|
1280 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1281 | "if this is windows, they already arrived\n"); |
|
|
1282 | } |
|
|
1283 | |
|
|
1284 | ... |
|
|
1285 | ev_stat passwd; |
|
|
1286 | |
|
|
1287 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1288 | ev_stat_start (loop, &passwd); |
1076 | |
1289 | |
1077 | |
1290 | |
1078 | |
1291 | |
1079 | |
1292 | |
1080 | </pre> |
1293 | </pre> |
… | |
… | |
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> |
1339 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2> |
1127 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1340 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1128 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1341 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1129 | prepare watchers get invoked before the process blocks and check watchers |
1342 | prepare watchers get invoked before the process blocks and check watchers |
1130 | afterwards.</p> |
1343 | afterwards.</p> |
|
|
1344 | <p>You <i>must not</i> call <code>ev_loop</code> or similar functions that enter |
|
|
1345 | the current event loop from either <code>ev_prepare</code> or <code>ev_check</code> |
|
|
1346 | watchers. Other loops than the current one are fine, however. The |
|
|
1347 | rationale behind this is that you do not need to check for recursion in |
|
|
1348 | those watchers, i.e. the sequence will always be <code>ev_prepare</code>, blocking, |
|
|
1349 | <code>ev_check</code> so if you have one watcher of each kind they will always be |
|
|
1350 | called in pairs bracketing the blocking call.</p> |
1131 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1351 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1132 | their use is somewhat advanced. This could be used, for example, to track |
1352 | their use is somewhat advanced. This could be used, for example, to track |
1133 | variable changes, implement your own watchers, integrate net-snmp or a |
1353 | variable changes, implement your own watchers, integrate net-snmp or a |
1134 | coroutine library and lots more.</p> |
1354 | coroutine library and lots more. They are also occasionally useful if |
|
|
1355 | you cache some data and want to flush it before blocking (for example, |
|
|
1356 | in X programs you might want to do an <code>XFlush ()</code> in an <code>ev_prepare</code> |
|
|
1357 | watcher).</p> |
1135 | <p>This is done by examining in each prepare call which file descriptors need |
1358 | <p>This is done by examining in each prepare call which file descriptors need |
1136 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1359 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1137 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1360 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1138 | provide just this functionality). Then, in the check watcher you check for |
1361 | provide just this functionality). Then, in the check watcher you check for |
1139 | any events that occured (by checking the pending status of all watchers |
1362 | any events that occured (by checking the pending status of all watchers |
… | |
… | |
1155 | <p>Initialises and configures the prepare or check watcher - they have no |
1378 | <p>Initialises and configures the prepare or check watcher - they have no |
1156 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1379 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1157 | macros, but using them is utterly, utterly and completely pointless.</p> |
1380 | macros, but using them is utterly, utterly and completely pointless.</p> |
1158 | </dd> |
1381 | </dd> |
1159 | </dl> |
1382 | </dl> |
1160 | <p>Example: *TODO*.</p> |
1383 | <p>Example: To include a library such as adns, you would add IO watchers |
|
|
1384 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1385 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1386 | pseudo-code only of course:</p> |
|
|
1387 | <pre> static ev_io iow [nfd]; |
|
|
1388 | static ev_timer tw; |
1161 | |
1389 | |
|
|
1390 | static void |
|
|
1391 | io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1392 | { |
|
|
1393 | // set the relevant poll flags |
|
|
1394 | // could also call adns_processreadable etc. here |
|
|
1395 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1396 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1397 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1398 | } |
1162 | |
1399 | |
|
|
1400 | // create io watchers for each fd and a timer before blocking |
|
|
1401 | static void |
|
|
1402 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1403 | { |
|
|
1404 | int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1405 | // actual code will need to loop here and realloc etc. |
|
|
1406 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1163 | |
1407 | |
|
|
1408 | /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1409 | ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1410 | ev_timer_start (loop, &tw); |
1164 | |
1411 | |
|
|
1412 | // create on ev_io per pollfd |
|
|
1413 | for (int i = 0; i < nfd; ++i) |
|
|
1414 | { |
|
|
1415 | ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1416 | ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1417 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1418 | |
|
|
1419 | fds [i].revents = 0; |
|
|
1420 | iow [i].data = fds + i; |
|
|
1421 | ev_io_start (loop, iow + i); |
|
|
1422 | } |
|
|
1423 | } |
|
|
1424 | |
|
|
1425 | // stop all watchers after blocking |
|
|
1426 | static void |
|
|
1427 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1428 | { |
|
|
1429 | ev_timer_stop (loop, &tw); |
|
|
1430 | |
|
|
1431 | for (int i = 0; i < nfd; ++i) |
|
|
1432 | ev_io_stop (loop, iow + i); |
|
|
1433 | |
|
|
1434 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1435 | } |
|
|
1436 | |
|
|
1437 | |
|
|
1438 | |
|
|
1439 | |
|
|
1440 | </pre> |
1165 | |
1441 | |
1166 | </div> |
1442 | </div> |
1167 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1443 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1168 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1444 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1169 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1445 | <p>This is a rather advanced watcher type that lets you embed one event loop |
… | |
… | |
1239 | <dt>ev_embed_sweep (loop, ev_embed *)</dt> |
1515 | <dt>ev_embed_sweep (loop, ev_embed *)</dt> |
1240 | <dd> |
1516 | <dd> |
1241 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1517 | <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 |
1518 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1243 | apropriate way for embedded loops.</p> |
1519 | apropriate way for embedded loops.</p> |
|
|
1520 | </dd> |
|
|
1521 | <dt>struct ev_loop *loop [read-only]</dt> |
|
|
1522 | <dd> |
|
|
1523 | <p>The embedded event loop.</p> |
|
|
1524 | </dd> |
|
|
1525 | </dl> |
|
|
1526 | |
|
|
1527 | |
|
|
1528 | |
|
|
1529 | |
|
|
1530 | |
|
|
1531 | </div> |
|
|
1532 | <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> |
|
|
1533 | <div id="code_ev_fork_code_the_audacity_to_re-2"> |
|
|
1534 | <p>Fork watchers are called when a <code>fork ()</code> was detected (usually because |
|
|
1535 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1536 | <code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the |
|
|
1537 | event loop blocks next and before <code>ev_check</code> watchers are being called, |
|
|
1538 | and only in the child after the fork. If whoever good citizen calling |
|
|
1539 | <code>ev_default_fork</code> cheats and calls it in the wrong process, the fork |
|
|
1540 | handlers will be invoked, too, of course.</p> |
|
|
1541 | <dl> |
|
|
1542 | <dt>ev_fork_init (ev_signal *, callback)</dt> |
|
|
1543 | <dd> |
|
|
1544 | <p>Initialises and configures the fork watcher - it has no parameters of any |
|
|
1545 | kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless, |
|
|
1546 | believe me.</p> |
1244 | </dd> |
1547 | </dd> |
1245 | </dl> |
1548 | </dl> |
1246 | |
1549 | |
1247 | |
1550 | |
1248 | |
1551 | |
… | |
… | |
1398 | </dd> |
1701 | </dd> |
1399 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1702 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1400 | <dd> |
1703 | <dd> |
1401 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1704 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1402 | </dd> |
1705 | </dd> |
|
|
1706 | <dt>w->update () <code>ev::stat</code> only</dt> |
|
|
1707 | <dd> |
|
|
1708 | <p>Invokes <code>ev_stat_stat</code>.</p> |
|
|
1709 | </dd> |
1403 | </dl> |
1710 | </dl> |
1404 | </p> |
1711 | </p> |
1405 | </dd> |
1712 | </dd> |
1406 | </dl> |
1713 | </dl> |
1407 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
1714 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1418 | : io (this, &myclass::io_cb), |
1725 | : io (this, &myclass::io_cb), |
1419 | idle (this, &myclass::idle_cb) |
1726 | idle (this, &myclass::idle_cb) |
1420 | { |
1727 | { |
1421 | io.start (fd, ev::READ); |
1728 | io.start (fd, ev::READ); |
1422 | } |
1729 | } |
|
|
1730 | |
|
|
1731 | |
|
|
1732 | |
|
|
1733 | |
|
|
1734 | </pre> |
|
|
1735 | |
|
|
1736 | </div> |
|
|
1737 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1><p><a href="#TOP" class="toplink">Top</a></p> |
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1738 | <div id="MACRO_MAGIC_CONTENT"> |
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1739 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
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1740 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
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1741 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
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1742 | <p>To make it easier to write programs that cope with either variant, the |
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1743 | following macros are defined:</p> |
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1744 | <dl> |
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1745 | <dt><code>EV_A</code>, <code>EV_A_</code></dt> |
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1746 | <dd> |
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1747 | <p>This provides the loop <i>argument</i> for functions, if one is required ("ev |
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1748 | loop argument"). The <code>EV_A</code> form is used when this is the sole argument, |
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1749 | <code>EV_A_</code> is used when other arguments are following. Example:</p> |
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1750 | <pre> ev_unref (EV_A); |
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1751 | ev_timer_add (EV_A_ watcher); |
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1752 | ev_loop (EV_A_ 0); |
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1753 | |
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1754 | </pre> |
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1755 | <p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope, |
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1756 | which is often provided by the following macro.</p> |
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1757 | </dd> |
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1758 | <dt><code>EV_P</code>, <code>EV_P_</code></dt> |
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1759 | <dd> |
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1760 | <p>This provides the loop <i>parameter</i> for functions, if one is required ("ev |
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1761 | loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter, |
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1762 | <code>EV_P_</code> is used when other parameters are following. Example:</p> |
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1763 | <pre> // this is how ev_unref is being declared |
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1764 | static void ev_unref (EV_P); |
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1765 | |
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1766 | // this is how you can declare your typical callback |
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1767 | static void cb (EV_P_ ev_timer *w, int revents) |
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1768 | |
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1769 | </pre> |
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1770 | <p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite |
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1771 | suitable for use with <code>EV_A</code>.</p> |
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1772 | </dd> |
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1773 | <dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt> |
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1774 | <dd> |
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1775 | <p>Similar to the other two macros, this gives you the value of the default |
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1776 | loop, if multiple loops are supported ("ev loop default").</p> |
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1777 | </dd> |
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1778 | </dl> |
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1779 | <p>Example: Declare and initialise a check watcher, working regardless of |
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1780 | wether multiple loops are supported or not.</p> |
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1781 | <pre> static void |
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1782 | check_cb (EV_P_ ev_timer *w, int revents) |
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1783 | { |
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1784 | ev_check_stop (EV_A_ w); |
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1785 | } |
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1786 | |
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1787 | ev_check check; |
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1788 | ev_check_init (&check, check_cb); |
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1789 | ev_check_start (EV_DEFAULT_ &check); |
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1790 | ev_loop (EV_DEFAULT_ 0); |
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1791 | |
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1792 | |
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1793 | |
1423 | |
1794 | |
1424 | </pre> |
1795 | </pre> |
1425 | |
1796 | |
1426 | </div> |
1797 | </div> |
1427 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1798 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
… | |
… | |
1638 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
2009 | 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 |
2010 | additional independent event loops. Otherwise there will be no support |
1640 | for multiple event loops and there is no first event loop pointer |
2011 | for multiple event loops and there is no first event loop pointer |
1641 | argument. Instead, all functions act on the single default loop.</p> |
2012 | argument. Instead, all functions act on the single default loop.</p> |
1642 | </dd> |
2013 | </dd> |
1643 | <dt>EV_PERIODICS</dt> |
2014 | <dt>EV_PERIODIC_ENABLE</dt> |
1644 | <dd> |
2015 | <dd> |
1645 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported, |
2016 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If |
1646 | otherwise not. This saves a few kb of code.</p> |
2017 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
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2018 | code.</p> |
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2019 | </dd> |
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2020 | <dt>EV_EMBED_ENABLE</dt> |
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2021 | <dd> |
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2022 | <p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If |
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2023 | defined to be <code>0</code>, then they are not.</p> |
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2024 | </dd> |
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2025 | <dt>EV_STAT_ENABLE</dt> |
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2026 | <dd> |
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2027 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
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2028 | defined to be <code>0</code>, then they are not.</p> |
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2029 | </dd> |
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2030 | <dt>EV_FORK_ENABLE</dt> |
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2031 | <dd> |
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2032 | <p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If |
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2033 | defined to be <code>0</code>, then they are not.</p> |
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2034 | </dd> |
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2035 | <dt>EV_MINIMAL</dt> |
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2036 | <dd> |
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2037 | <p>If you need to shave off some kilobytes of code at the expense of some |
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2038 | speed, define this symbol to <code>1</code>. Currently only used for gcc to override |
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2039 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
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2040 | </dd> |
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2041 | <dt>EV_PID_HASHSIZE</dt> |
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2042 | <dd> |
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2043 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
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2044 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
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2045 | than enough. If you need to manage thousands of children you might want to |
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2046 | increase this value.</p> |
1647 | </dd> |
2047 | </dd> |
1648 | <dt>EV_COMMON</dt> |
2048 | <dt>EV_COMMON</dt> |
1649 | <dd> |
2049 | <dd> |
1650 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2050 | <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 |
2051 | this macro to a something else you can include more and other types of |
… | |
… | |
1691 | </pre> |
2091 | </pre> |
1692 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
2092 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
1693 | <pre> #include "ev_cpp.h" |
2093 | <pre> #include "ev_cpp.h" |
1694 | #include "ev.c" |
2094 | #include "ev.c" |
1695 | |
2095 | |
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2096 | |
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2097 | |
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2098 | |
1696 | </pre> |
2099 | </pre> |
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2100 | |
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2101 | </div> |
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2102 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
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2103 | <div id="COMPLEXITIES_CONTENT"> |
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2104 | <p>In this section the complexities of (many of) the algorithms used inside |
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2105 | libev will be explained. For complexity discussions about backends see the |
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2106 | documentation for <code>ev_default_init</code>.</p> |
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2107 | <p> |
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2108 | <dl> |
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2109 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
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2110 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
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2111 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
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2112 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
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2113 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))</dt> |
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2114 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
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2115 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
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2116 | <dt>Activating one watcher: O(1)</dt> |
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2117 | </dl> |
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2118 | </p> |
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2119 | |
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2120 | |
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2121 | |
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2122 | |
1697 | |
2123 | |
1698 | </div> |
2124 | </div> |
1699 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2125 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1700 | <div id="AUTHOR_CONTENT"> |
2126 | <div id="AUTHOR_CONTENT"> |
1701 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2127 | <p>Marc Lehmann <libev@schmorp.de>.</p> |