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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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7 | <meta name="inputfile" content="<standard input>" /> |
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12 | <body> |
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13 | <div class="pod"> |
13 | <div class="pod"> |
14 | <!-- INDEX START --> |
14 | <!-- INDEX START --> |
15 | <h3 id="TOP">Index</h3> |
15 | <h3 id="TOP">Index</h3> |
16 | |
16 | |
17 | <ul><li><a href="#NAME">NAME</a></li> |
17 | <ul><li><a href="#NAME">NAME</a></li> |
18 | <li><a href="#SYNOPSIS">SYNOPSIS</a></li> |
18 | <li><a href="#SYNOPSIS">SYNOPSIS</a></li> |
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19 | <li><a href="#EXAMPLE_PROGRAM">EXAMPLE PROGRAM</a></li> |
19 | <li><a href="#DESCRIPTION">DESCRIPTION</a></li> |
20 | <li><a href="#DESCRIPTION">DESCRIPTION</a></li> |
20 | <li><a href="#FEATURES">FEATURES</a></li> |
21 | <li><a href="#FEATURES">FEATURES</a></li> |
21 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
22 | <li><a href="#CONVENTIONS">CONVENTIONS</a></li> |
22 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
23 | <li><a href="#TIME_REPRESENTATION">TIME REPRESENTATION</a></li> |
23 | <li><a href="#GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</a></li> |
24 | <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> |
25 | <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> |
26 | <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> |
27 | <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> |
28 | <li><a href="#ASSOCIATING_CUSTOM_DATA_WITH_A_WATCH">ASSOCIATING CUSTOM DATA WITH A WATCHER</a></li> |
28 | </ul> |
29 | </ul> |
29 | </li> |
30 | </li> |
30 | <li><a href="#WATCHER_TYPES">WATCHER TYPES</a> |
31 | <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> |
32 | <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> |
33 | <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> |
34 | <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> |
35 | <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> |
36 | <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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37 | <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> |
38 | <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> |
39 | <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> |
40 | <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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41 | <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> |
42 | </ul> |
40 | </li> |
43 | </li> |
41 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
44 | <li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> |
42 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
45 | <li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> |
43 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
46 | <li><a href="#C_SUPPORT">C++ SUPPORT</a></li> |
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47 | <li><a href="#MACRO_MAGIC">MACRO MAGIC</a></li> |
44 | <li><a href="#EMBEDDING">EMBEDDING</a> |
48 | <li><a href="#EMBEDDING">EMBEDDING</a> |
45 | <ul><li><a href="#FILESETS">FILESETS</a> |
49 | <ul><li><a href="#FILESETS">FILESETS</a> |
46 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
50 | <ul><li><a href="#CORE_EVENT_LOOP">CORE EVENT LOOP</a></li> |
47 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
51 | <li><a href="#LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</a></li> |
48 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
52 | <li><a href="#AUTOCONF_SUPPORT">AUTOCONF SUPPORT</a></li> |
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50 | </li> |
54 | </li> |
51 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
55 | <li><a href="#PREPROCESSOR_SYMBOLS_MACROS">PREPROCESSOR SYMBOLS/MACROS</a></li> |
52 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
56 | <li><a href="#EXAMPLES">EXAMPLES</a></li> |
53 | </ul> |
57 | </ul> |
54 | </li> |
58 | </li> |
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59 | <li><a href="#COMPLEXITIES">COMPLEXITIES</a></li> |
55 | <li><a href="#AUTHOR">AUTHOR</a> |
60 | <li><a href="#AUTHOR">AUTHOR</a> |
56 | </li> |
61 | </li> |
57 | </ul><hr /> |
62 | </ul><hr /> |
58 | <!-- INDEX END --> |
63 | <!-- INDEX END --> |
59 | |
64 | |
60 | <h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p> |
65 | <h1 id="NAME">NAME</h1> |
61 | <div id="NAME_CONTENT"> |
66 | <div id="NAME_CONTENT"> |
62 | <p>libev - a high performance full-featured event loop written in C</p> |
67 | <p>libev - a high performance full-featured event loop written in C</p> |
63 | |
68 | |
64 | </div> |
69 | </div> |
65 | <h1 id="SYNOPSIS">SYNOPSIS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
70 | <h1 id="SYNOPSIS">SYNOPSIS</h1> |
66 | <div id="SYNOPSIS_CONTENT"> |
71 | <div id="SYNOPSIS_CONTENT"> |
67 | <pre> #include <ev.h> |
72 | <pre> #include <ev.h> |
68 | |
73 | |
69 | </pre> |
74 | </pre> |
70 | |
75 | |
71 | </div> |
76 | </div> |
72 | <h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
77 | <h1 id="EXAMPLE_PROGRAM">EXAMPLE PROGRAM</h1> |
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78 | <div id="EXAMPLE_PROGRAM_CONTENT"> |
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79 | <pre> #include <ev.h> |
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80 | |
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81 | ev_io stdin_watcher; |
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82 | ev_timer timeout_watcher; |
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83 | |
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84 | /* called when data readable on stdin */ |
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85 | static void |
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86 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
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87 | { |
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88 | /* puts ("stdin ready"); */ |
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89 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
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90 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
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91 | } |
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92 | |
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93 | static void |
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94 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
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95 | { |
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96 | /* puts ("timeout"); */ |
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97 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
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98 | } |
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99 | |
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100 | int |
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101 | main (void) |
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102 | { |
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103 | struct ev_loop *loop = ev_default_loop (0); |
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104 | |
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105 | /* initialise an io watcher, then start it */ |
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106 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
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107 | ev_io_start (loop, &stdin_watcher); |
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108 | |
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109 | /* simple non-repeating 5.5 second timeout */ |
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110 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
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111 | ev_timer_start (loop, &timeout_watcher); |
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112 | |
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113 | /* loop till timeout or data ready */ |
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114 | ev_loop (loop, 0); |
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115 | |
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116 | return 0; |
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117 | } |
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118 | |
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119 | </pre> |
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120 | |
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121 | </div> |
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122 | <h1 id="DESCRIPTION">DESCRIPTION</h1> |
73 | <div id="DESCRIPTION_CONTENT"> |
123 | <div id="DESCRIPTION_CONTENT"> |
74 | <p>Libev is an event loop: you register interest in certain events (such as a |
124 | <p>Libev is an event loop: you register interest in certain events (such as a |
75 | file descriptor being readable or a timeout occuring), and it will manage |
125 | file descriptor being readable or a timeout occuring), and it will manage |
76 | these event sources and provide your program with events.</p> |
126 | these event sources and provide your program with events.</p> |
77 | <p>To do this, it must take more or less complete control over your process |
127 | <p>To do this, it must take more or less complete control over your process |
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81 | watchers</i>, which are relatively small C structures you initialise with the |
131 | watchers</i>, which are relatively small C structures you initialise with the |
82 | details of the event, and then hand it over to libev by <i>starting</i> the |
132 | details of the event, and then hand it over to libev by <i>starting</i> the |
83 | watcher.</p> |
133 | watcher.</p> |
84 | |
134 | |
85 | </div> |
135 | </div> |
86 | <h1 id="FEATURES">FEATURES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
136 | <h1 id="FEATURES">FEATURES</h1> |
87 | <div id="FEATURES_CONTENT"> |
137 | <div id="FEATURES_CONTENT"> |
88 | <p>Libev supports select, poll, the linux-specific epoll and the bsd-specific |
138 | <p>Libev supports <code>select</code>, <code>poll</code>, the Linux-specific <code>epoll</code>, the |
89 | kqueue mechanisms for file descriptor events, relative timers, absolute |
139 | BSD-specific <code>kqueue</code> and the Solaris-specific event port mechanisms |
90 | timers with customised rescheduling, signal events, process status change |
140 | for file descriptor events (<code>ev_io</code>), the Linux <code>inotify</code> interface |
91 | events (related to SIGCHLD), and event watchers dealing with the event |
141 | (for <code>ev_stat</code>), relative timers (<code>ev_timer</code>), absolute timers |
92 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
142 | with customised rescheduling (<code>ev_periodic</code>), synchronous signals |
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143 | (<code>ev_signal</code>), process status change events (<code>ev_child</code>), and event |
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144 | watchers dealing with the event loop mechanism itself (<code>ev_idle</code>, |
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145 | <code>ev_embed</code>, <code>ev_prepare</code> and <code>ev_check</code> watchers) as well as |
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146 | file watchers (<code>ev_stat</code>) and even limited support for fork events |
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147 | (<code>ev_fork</code>).</p> |
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148 | <p>It also is quite fast (see this |
93 | fast (see this <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing |
149 | <a href="http://libev.schmorp.de/bench.html">benchmark</a> comparing it to libevent |
94 | it to libevent for example).</p> |
150 | for example).</p> |
95 | |
151 | |
96 | </div> |
152 | </div> |
97 | <h1 id="CONVENTIONS">CONVENTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
153 | <h1 id="CONVENTIONS">CONVENTIONS</h1> |
98 | <div id="CONVENTIONS_CONTENT"> |
154 | <div id="CONVENTIONS_CONTENT"> |
99 | <p>Libev is very configurable. In this manual the default configuration |
155 | <p>Libev is very configurable. In this manual the default configuration will |
100 | will be described, which supports multiple event loops. For more info |
156 | be described, which supports multiple event loops. For more info about |
101 | about various configuration options please have a look at the file |
157 | various configuration options please have a look at <strong>EMBED</strong> section in |
102 | <cite>README.embed</cite> in the libev distribution. If libev was configured without |
158 | this manual. If libev was configured without support for multiple event |
103 | support for multiple event loops, then all functions taking an initial |
159 | loops, then all functions taking an initial argument of name <code>loop</code> |
104 | argument of name <code>loop</code> (which is always of type <code>struct ev_loop *</code>) |
160 | (which is always of type <code>struct ev_loop *</code>) will not have this argument.</p> |
105 | will not have this argument.</p> |
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106 | |
161 | |
107 | </div> |
162 | </div> |
108 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
163 | <h1 id="TIME_REPRESENTATION">TIME REPRESENTATION</h1> |
109 | <div id="TIME_REPRESENTATION_CONTENT"> |
164 | <div id="TIME_REPRESENTATION_CONTENT"> |
110 | <p>Libev represents time as a single floating point number, representing the |
165 | <p>Libev represents time as a single floating point number, representing the |
111 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
166 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
112 | the beginning of 1970, details are complicated, don't ask). This type is |
167 | 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 |
168 | 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 |
169 | 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> |
170 | it, you should treat it as such.</p> |
116 | |
171 | |
117 | |
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118 | |
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119 | |
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120 | |
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121 | </div> |
172 | </div> |
122 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
173 | <h1 id="GLOBAL_FUNCTIONS">GLOBAL FUNCTIONS</h1> |
123 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
174 | <div id="GLOBAL_FUNCTIONS_CONTENT"> |
124 | <p>These functions can be called anytime, even before initialising the |
175 | <p>These functions can be called anytime, even before initialising the |
125 | library in any way.</p> |
176 | library in any way.</p> |
126 | <dl> |
177 | <dl> |
127 | <dt>ev_tstamp ev_time ()</dt> |
178 | <dt>ev_tstamp ev_time ()</dt> |
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140 | version of the library your program was compiled against.</p> |
191 | version of the library your program was compiled against.</p> |
141 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
192 | <p>Usually, it's a good idea to terminate if the major versions mismatch, |
142 | as this indicates an incompatible change. Minor versions are usually |
193 | as this indicates an incompatible change. Minor versions are usually |
143 | compatible to older versions, so a larger minor version alone is usually |
194 | compatible to older versions, so a larger minor version alone is usually |
144 | not a problem.</p> |
195 | not a problem.</p> |
145 | <p>Example: make sure we haven't accidentally been linked against the wrong |
196 | <p>Example: Make sure we haven't accidentally been linked against the wrong |
146 | version:</p> |
197 | version.</p> |
147 | <pre> assert (("libev version mismatch", |
198 | <pre> assert (("libev version mismatch", |
148 | ev_version_major () == EV_VERSION_MAJOR |
199 | ev_version_major () == EV_VERSION_MAJOR |
149 | && ev_version_minor () >= EV_VERSION_MINOR)); |
200 | && ev_version_minor () >= EV_VERSION_MINOR)); |
150 | |
201 | |
151 | </pre> |
202 | </pre> |
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181 | recommended ones.</p> |
232 | recommended ones.</p> |
182 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
233 | <p>See the description of <code>ev_embed</code> watchers for more info.</p> |
183 | </dd> |
234 | </dd> |
184 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
235 | <dt>ev_set_allocator (void *(*cb)(void *ptr, long size))</dt> |
185 | <dd> |
236 | <dd> |
186 | <p>Sets the allocation function to use (the prototype is similar to the |
237 | <p>Sets the allocation function to use (the prototype is similar - the |
187 | realloc C function, the semantics are identical). It is used to allocate |
238 | semantics is identical - to the realloc C function). It is used to |
188 | and free memory (no surprises here). If it returns zero when memory |
239 | allocate and free memory (no surprises here). If it returns zero when |
189 | needs to be allocated, the library might abort or take some potentially |
240 | memory needs to be allocated, the library might abort or take some |
190 | destructive action. The default is your system realloc function.</p> |
241 | potentially destructive action. The default is your system realloc |
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242 | function.</p> |
191 | <p>You could override this function in high-availability programs to, say, |
243 | <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, |
244 | 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> |
245 | 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 |
246 | <p>Example: Replace the libev allocator with one that waits a bit and then |
195 | retries: better than mine).</p> |
247 | retries).</p> |
196 | <pre> static void * |
248 | <pre> static void * |
197 | persistent_realloc (void *ptr, long size) |
249 | persistent_realloc (void *ptr, size_t size) |
198 | { |
250 | { |
199 | for (;;) |
251 | for (;;) |
200 | { |
252 | { |
201 | void *newptr = realloc (ptr, size); |
253 | void *newptr = realloc (ptr, size); |
202 | |
254 | |
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219 | indicating the system call or subsystem causing the problem. If this |
271 | indicating the system call or subsystem causing the problem. If this |
220 | callback is set, then libev will expect it to remedy the sitution, no |
272 | callback is set, then libev will expect it to remedy the sitution, no |
221 | matter what, when it returns. That is, libev will generally retry the |
273 | matter what, when it returns. That is, libev will generally retry the |
222 | requested operation, or, if the condition doesn't go away, do bad stuff |
274 | requested operation, or, if the condition doesn't go away, do bad stuff |
223 | (such as abort).</p> |
275 | (such as abort).</p> |
224 | <p>Example: do the same thing as libev does internally:</p> |
276 | <p>Example: This is basically the same thing that libev does internally, too.</p> |
225 | <pre> static void |
277 | <pre> static void |
226 | fatal_error (const char *msg) |
278 | fatal_error (const char *msg) |
227 | { |
279 | { |
228 | perror (msg); |
280 | perror (msg); |
229 | abort (); |
281 | abort (); |
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235 | </pre> |
287 | </pre> |
236 | </dd> |
288 | </dd> |
237 | </dl> |
289 | </dl> |
238 | |
290 | |
239 | </div> |
291 | </div> |
240 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1><p><a href="#TOP" class="toplink">Top</a></p> |
292 | <h1 id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP">FUNCTIONS CONTROLLING THE EVENT LOOP</h1> |
241 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
293 | <div id="FUNCTIONS_CONTROLLING_THE_EVENT_LOOP-2"> |
242 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
294 | <p>An event loop is described by a <code>struct ev_loop *</code>. The library knows two |
243 | types of such loops, the <i>default</i> loop, which supports signals and child |
295 | types of such loops, the <i>default</i> loop, which supports signals and child |
244 | events, and dynamically created loops which do not.</p> |
296 | events, and dynamically created loops which do not.</p> |
245 | <p>If you use threads, a common model is to run the default event loop |
297 | <p>If you use threads, a common model is to run the default event loop |
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365 | <dd> |
417 | <dd> |
366 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
418 | <p>Similar to <code>ev_default_loop</code>, but always creates a new event loop that is |
367 | always distinct from the default loop. Unlike the default loop, it cannot |
419 | always distinct from the default loop. Unlike the default loop, it cannot |
368 | handle signal and child watchers, and attempts to do so will be greeted by |
420 | handle signal and child watchers, and attempts to do so will be greeted by |
369 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
421 | undefined behaviour (or a failed assertion if assertions are enabled).</p> |
370 | <p>Example: try to create a event loop that uses epoll and nothing else.</p> |
422 | <p>Example: Try to create a event loop that uses epoll and nothing else.</p> |
371 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
423 | <pre> struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
372 | if (!epoller) |
424 | if (!epoller) |
373 | fatal ("no epoll found here, maybe it hides under your chair"); |
425 | fatal ("no epoll found here, maybe it hides under your chair"); |
374 | |
426 | |
375 | </pre> |
427 | </pre> |
… | |
… | |
468 | be handled here by queueing them when their watcher gets executed. |
520 | be handled here by queueing them when their watcher gets executed. |
469 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
521 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
470 | were used, return, otherwise continue with step *. |
522 | were used, return, otherwise continue with step *. |
471 | |
523 | |
472 | </pre> |
524 | </pre> |
473 | <p>Example: queue some jobs and then loop until no events are outsanding |
525 | <p>Example: Queue some jobs and then loop until no events are outsanding |
474 | anymore.</p> |
526 | anymore.</p> |
475 | <pre> ... queue jobs here, make sure they register event watchers as long |
527 | <pre> ... queue jobs here, make sure they register event watchers as long |
476 | ... as they still have work to do (even an idle watcher will do..) |
528 | ... as they still have work to do (even an idle watcher will do..) |
477 | ev_loop (my_loop, 0); |
529 | ev_loop (my_loop, 0); |
478 | ... jobs done. yeah! |
530 | ... jobs done. yeah! |
… | |
… | |
497 | example, libev itself uses this for its internal signal pipe: It is not |
549 | example, libev itself uses this for its internal signal pipe: It is not |
498 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
550 | visible to the libev user and should not keep <code>ev_loop</code> from exiting if |
499 | no event watchers registered by it are active. It is also an excellent |
551 | no event watchers registered by it are active. It is also an excellent |
500 | way to do this for generic recurring timers or from within third-party |
552 | way to do this for generic recurring timers or from within third-party |
501 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
553 | libraries. Just remember to <i>unref after start</i> and <i>ref before stop</i>.</p> |
502 | <p>Example: create a signal watcher, but keep it from keeping <code>ev_loop</code> |
554 | <p>Example: Create a signal watcher, but keep it from keeping <code>ev_loop</code> |
503 | running when nothing else is active.</p> |
555 | running when nothing else is active.</p> |
504 | <pre> struct dv_signal exitsig; |
556 | <pre> struct ev_signal exitsig; |
505 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
557 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
506 | ev_signal_start (myloop, &exitsig); |
558 | ev_signal_start (loop, &exitsig); |
507 | evf_unref (myloop); |
559 | evf_unref (loop); |
508 | |
560 | |
509 | </pre> |
561 | </pre> |
510 | <p>Example: for some weird reason, unregister the above signal handler again.</p> |
562 | <p>Example: For some weird reason, unregister the above signal handler again.</p> |
511 | <pre> ev_ref (myloop); |
563 | <pre> ev_ref (loop); |
512 | ev_signal_stop (myloop, &exitsig); |
564 | ev_signal_stop (loop, &exitsig); |
513 | |
565 | |
514 | </pre> |
566 | </pre> |
515 | </dd> |
567 | </dd> |
516 | </dl> |
568 | </dl> |
517 | |
569 | |
|
|
570 | |
|
|
571 | |
|
|
572 | |
|
|
573 | |
518 | </div> |
574 | </div> |
519 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1><p><a href="#TOP" class="toplink">Top</a></p> |
575 | <h1 id="ANATOMY_OF_A_WATCHER">ANATOMY OF A WATCHER</h1> |
520 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
576 | <div id="ANATOMY_OF_A_WATCHER_CONTENT"> |
521 | <p>A watcher is a structure that you create and register to record your |
577 | <p>A watcher is a structure that you create and register to record your |
522 | interest in some event. For instance, if you want to wait for STDIN to |
578 | interest in some event. For instance, if you want to wait for STDIN to |
523 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
579 | become readable, you would create an <code>ev_io</code> watcher for that:</p> |
524 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
580 | <pre> static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
581 | </dd> |
637 | </dd> |
582 | <dt><code>EV_CHILD</code></dt> |
638 | <dt><code>EV_CHILD</code></dt> |
583 | <dd> |
639 | <dd> |
584 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
640 | <p>The pid specified in the <code>ev_child</code> watcher has received a status change.</p> |
585 | </dd> |
641 | </dd> |
|
|
642 | <dt><code>EV_STAT</code></dt> |
|
|
643 | <dd> |
|
|
644 | <p>The path specified in the <code>ev_stat</code> watcher changed its attributes somehow.</p> |
|
|
645 | </dd> |
586 | <dt><code>EV_IDLE</code></dt> |
646 | <dt><code>EV_IDLE</code></dt> |
587 | <dd> |
647 | <dd> |
588 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
648 | <p>The <code>ev_idle</code> watcher has determined that you have nothing better to do.</p> |
589 | </dd> |
649 | </dd> |
590 | <dt><code>EV_PREPARE</code></dt> |
650 | <dt><code>EV_PREPARE</code></dt> |
… | |
… | |
595 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
655 | <code>ev_loop</code> has gathered them, but before it invokes any callbacks for any |
596 | received events. Callbacks of both watcher types can start and stop as |
656 | received events. Callbacks of both watcher types can start and stop as |
597 | many watchers as they want, and all of them will be taken into account |
657 | many watchers as they want, and all of them will be taken into account |
598 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
658 | (for example, a <code>ev_prepare</code> watcher might start an idle watcher to keep |
599 | <code>ev_loop</code> from blocking).</p> |
659 | <code>ev_loop</code> from blocking).</p> |
|
|
660 | </dd> |
|
|
661 | <dt><code>EV_EMBED</code></dt> |
|
|
662 | <dd> |
|
|
663 | <p>The embedded event loop specified in the <code>ev_embed</code> watcher needs attention.</p> |
|
|
664 | </dd> |
|
|
665 | <dt><code>EV_FORK</code></dt> |
|
|
666 | <dd> |
|
|
667 | <p>The event loop has been resumed in the child process after fork (see |
|
|
668 | <code>ev_fork</code>).</p> |
600 | </dd> |
669 | </dd> |
601 | <dt><code>EV_ERROR</code></dt> |
670 | <dt><code>EV_ERROR</code></dt> |
602 | <dd> |
671 | <dd> |
603 | <p>An unspecified error has occured, the watcher has been stopped. This might |
672 | <p>An unspecified error has occured, the watcher has been stopped. This might |
604 | happen because the watcher could not be properly started because libev |
673 | happen because the watcher could not be properly started because libev |
… | |
… | |
612 | programs, though, so beware.</p> |
681 | programs, though, so beware.</p> |
613 | </dd> |
682 | </dd> |
614 | </dl> |
683 | </dl> |
615 | |
684 | |
616 | </div> |
685 | </div> |
617 | <h2 id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS">SUMMARY OF GENERIC WATCHER FUNCTIONS</h2> |
686 | <h2 id="GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</h2> |
618 | <div id="SUMMARY_OF_GENERIC_WATCHER_FUNCTIONS-2"> |
687 | <div id="GENERIC_WATCHER_FUNCTIONS_CONTENT"> |
619 | <p>In the following description, <code>TYPE</code> stands for the watcher type, |
688 | <p>In the following description, <code>TYPE</code> stands for the watcher type, |
620 | e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p> |
689 | e.g. <code>timer</code> for <code>ev_timer</code> watchers and <code>io</code> for <code>ev_io</code> watchers.</p> |
621 | <dl> |
690 | <dl> |
622 | <dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt> |
691 | <dt><code>ev_init</code> (ev_TYPE *watcher, callback)</dt> |
623 | <dd> |
692 | <dd> |
… | |
… | |
627 | the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the |
696 | the type-specific <code>ev_TYPE_set</code> macro afterwards to initialise the |
628 | type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro |
697 | type-specific parts. For each type there is also a <code>ev_TYPE_init</code> macro |
629 | which rolls both calls into one.</p> |
698 | which rolls both calls into one.</p> |
630 | <p>You can reinitialise a watcher at any time as long as it has been stopped |
699 | <p>You can reinitialise a watcher at any time as long as it has been stopped |
631 | (or never started) and there are no pending events outstanding.</p> |
700 | (or never started) and there are no pending events outstanding.</p> |
632 | <p>The callbakc is always of type <code>void (*)(ev_loop *loop, ev_TYPE *watcher, |
701 | <p>The callback is always of type <code>void (*)(ev_loop *loop, ev_TYPE *watcher, |
633 | int revents)</code>.</p> |
702 | int revents)</code>.</p> |
634 | </dd> |
703 | </dd> |
635 | <dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt> |
704 | <dt><code>ev_TYPE_set</code> (ev_TYPE *, [args])</dt> |
636 | <dd> |
705 | <dd> |
637 | <p>This macro initialises the type-specific parts of a watcher. You need to |
706 | <p>This macro initialises the type-specific parts of a watcher. You need to |
… | |
… | |
674 | events but its callback has not yet been invoked). As long as a watcher |
743 | events but its callback has not yet been invoked). As long as a watcher |
675 | is pending (but not active) you must not call an init function on it (but |
744 | is pending (but not active) you must not call an init function on it (but |
676 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
745 | <code>ev_TYPE_set</code> is safe) and you must make sure the watcher is available to |
677 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
746 | libev (e.g. you cnanot <code>free ()</code> it).</p> |
678 | </dd> |
747 | </dd> |
679 | <dt>callback = ev_cb (ev_TYPE *watcher)</dt> |
748 | <dt>callback ev_cb (ev_TYPE *watcher)</dt> |
680 | <dd> |
749 | <dd> |
681 | <p>Returns the callback currently set on the watcher.</p> |
750 | <p>Returns the callback currently set on the watcher.</p> |
682 | </dd> |
751 | </dd> |
683 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
752 | <dt>ev_cb_set (ev_TYPE *watcher, callback)</dt> |
684 | <dd> |
753 | <dd> |
… | |
… | |
716 | struct my_io *w = (struct my_io *)w_; |
785 | struct my_io *w = (struct my_io *)w_; |
717 | ... |
786 | ... |
718 | } |
787 | } |
719 | |
788 | |
720 | </pre> |
789 | </pre> |
721 | <p>More interesting and less C-conformant ways of catsing your callback type |
790 | <p>More interesting and less C-conformant ways of casting your callback type |
722 | have been omitted....</p> |
791 | instead have been omitted.</p> |
|
|
792 | <p>Another common scenario is having some data structure with multiple |
|
|
793 | watchers:</p> |
|
|
794 | <pre> struct my_biggy |
|
|
795 | { |
|
|
796 | int some_data; |
|
|
797 | ev_timer t1; |
|
|
798 | ev_timer t2; |
|
|
799 | } |
723 | |
800 | |
|
|
801 | </pre> |
|
|
802 | <p>In this case getting the pointer to <code>my_biggy</code> is a bit more complicated, |
|
|
803 | you need to use <code>offsetof</code>:</p> |
|
|
804 | <pre> #include <stddef.h> |
724 | |
805 | |
|
|
806 | static void |
|
|
807 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
808 | { |
|
|
809 | struct my_biggy big = (struct my_biggy * |
|
|
810 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
811 | } |
725 | |
812 | |
|
|
813 | static void |
|
|
814 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
815 | { |
|
|
816 | struct my_biggy big = (struct my_biggy * |
|
|
817 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
818 | } |
726 | |
819 | |
727 | |
820 | |
|
|
821 | |
|
|
822 | |
|
|
823 | </pre> |
|
|
824 | |
728 | </div> |
825 | </div> |
729 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1><p><a href="#TOP" class="toplink">Top</a></p> |
826 | <h1 id="WATCHER_TYPES">WATCHER TYPES</h1> |
730 | <div id="WATCHER_TYPES_CONTENT"> |
827 | <div id="WATCHER_TYPES_CONTENT"> |
731 | <p>This section describes each watcher in detail, but will not repeat |
828 | <p>This section describes each watcher in detail, but will not repeat |
732 | information given in the last section.</p> |
829 | information given in the last section. Any initialisation/set macros, |
|
|
830 | functions and members specific to the watcher type are explained.</p> |
|
|
831 | <p>Members are additionally marked with either <i>[read-only]</i>, meaning that, |
|
|
832 | while the watcher is active, you can look at the member and expect some |
|
|
833 | sensible content, but you must not modify it (you can modify it while the |
|
|
834 | watcher is stopped to your hearts content), or <i>[read-write]</i>, which |
|
|
835 | means you can expect it to have some sensible content while the watcher |
|
|
836 | is active, but you can also modify it. Modifying it may not do something |
|
|
837 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
838 | not crash or malfunction in any way.</p> |
733 | |
839 | |
734 | |
840 | |
735 | |
841 | |
736 | |
842 | |
737 | |
843 | |
738 | </div> |
844 | </div> |
739 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable</h2> |
845 | <h2 id="code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</h2> |
740 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
846 | <div id="code_ev_io_code_is_this_file_descrip-2"> |
741 | <p>I/O watchers check whether a file descriptor is readable or writable |
847 | <p>I/O watchers check whether a file descriptor is readable or writable |
742 | in each iteration of the event loop (This behaviour is called |
848 | in each iteration of the event loop, or, more precisely, when reading |
743 | level-triggering because you keep receiving events as long as the |
849 | would not block the process and writing would at least be able to write |
744 | condition persists. Remember you can stop the watcher if you don't want to |
850 | some data. This behaviour is called level-triggering because you keep |
745 | act on the event and neither want to receive future events).</p> |
851 | receiving events as long as the condition persists. Remember you can stop |
|
|
852 | the watcher if you don't want to act on the event and neither want to |
|
|
853 | receive future events.</p> |
746 | <p>In general you can register as many read and/or write event watchers per |
854 | <p>In general you can register as many read and/or write event watchers per |
747 | fd as you want (as long as you don't confuse yourself). Setting all file |
855 | fd as you want (as long as you don't confuse yourself). Setting all file |
748 | descriptors to non-blocking mode is also usually a good idea (but not |
856 | descriptors to non-blocking mode is also usually a good idea (but not |
749 | required if you know what you are doing).</p> |
857 | required if you know what you are doing).</p> |
750 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
858 | <p>You have to be careful with dup'ed file descriptors, though. Some backends |
751 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
859 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
752 | descriptors correctly if you register interest in two or more fds pointing |
860 | descriptors correctly if you register interest in two or more fds pointing |
753 | to the same underlying file/socket etc. description (that is, they share |
861 | to the same underlying file/socket/etc. description (that is, they share |
754 | the same underlying "file open").</p> |
862 | the same underlying "file open").</p> |
755 | <p>If you must do this, then force the use of a known-to-be-good backend |
863 | <p>If you must do this, then force the use of a known-to-be-good backend |
756 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
864 | (at the time of this writing, this includes only <code>EVBACKEND_SELECT</code> and |
757 | <code>EVBACKEND_POLL</code>).</p> |
865 | <code>EVBACKEND_POLL</code>).</p> |
|
|
866 | <p>Another thing you have to watch out for is that it is quite easy to |
|
|
867 | receive "spurious" readyness notifications, that is your callback might |
|
|
868 | be called with <code>EV_READ</code> but a subsequent <code>read</code>(2) will actually block |
|
|
869 | because there is no data. Not only are some backends known to create a |
|
|
870 | lot of those (for example solaris ports), it is very easy to get into |
|
|
871 | this situation even with a relatively standard program structure. Thus |
|
|
872 | it is best to always use non-blocking I/O: An extra <code>read</code>(2) returning |
|
|
873 | <code>EAGAIN</code> is far preferable to a program hanging until some data arrives.</p> |
|
|
874 | <p>If you cannot run the fd in non-blocking mode (for example you should not |
|
|
875 | play around with an Xlib connection), then you have to seperately re-test |
|
|
876 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
877 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
878 | its own, so its quite safe to use).</p> |
758 | <dl> |
879 | <dl> |
759 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
880 | <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> |
760 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
881 | <dt>ev_io_set (ev_io *, int fd, int events)</dt> |
761 | <dd> |
882 | <dd> |
762 | <p>Configures an <code>ev_io</code> watcher. The fd is the file descriptor to rceeive |
883 | <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to |
763 | events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or <code>EV_READ | |
884 | rceeive events for and events is either <code>EV_READ</code>, <code>EV_WRITE</code> or |
764 | EV_WRITE</code> to receive the given events.</p> |
885 | <code>EV_READ | EV_WRITE</code> to receive the given events.</p> |
765 | <p>Please note that most of the more scalable backend mechanisms (for example |
886 | </dd> |
766 | epoll and solaris ports) can result in spurious readyness notifications |
887 | <dt>int fd [read-only]</dt> |
767 | for file descriptors, so you practically need to use non-blocking I/O (and |
888 | <dd> |
768 | treat callback invocation as hint only), or retest separately with a safe |
889 | <p>The file descriptor being watched.</p> |
769 | interface before doing I/O (XLib can do this), or force the use of either |
890 | </dd> |
770 | <code>EVBACKEND_SELECT</code> or <code>EVBACKEND_POLL</code>, which don't suffer from this |
891 | <dt>int events [read-only]</dt> |
771 | problem. Also note that it is quite easy to have your callback invoked |
892 | <dd> |
772 | when the readyness condition is no longer valid even when employing |
893 | <p>The events being watched.</p> |
773 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
774 | I/O unconditionally.</p> |
|
|
775 | </dd> |
894 | </dd> |
776 | </dl> |
895 | </dl> |
777 | <p>Example: call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
896 | <p>Example: Call <code>stdin_readable_cb</code> when STDIN_FILENO has become, well |
778 | readable, but only once. Since it is likely line-buffered, you could |
897 | readable, but only once. Since it is likely line-buffered, you could |
779 | attempt to read a whole line in the callback:</p> |
898 | attempt to read a whole line in the callback.</p> |
780 | <pre> static void |
899 | <pre> static void |
781 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
900 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
782 | { |
901 | { |
783 | ev_io_stop (loop, w); |
902 | ev_io_stop (loop, w); |
784 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
903 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
… | |
… | |
795 | |
914 | |
796 | |
915 | |
797 | </pre> |
916 | </pre> |
798 | |
917 | |
799 | </div> |
918 | </div> |
800 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally recurring timeouts</h2> |
919 | <h2 id="code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</h2> |
801 | <div id="code_ev_timer_code_relative_and_opti-2"> |
920 | <div id="code_ev_timer_code_relative_and_opti-2"> |
802 | <p>Timer watchers are simple relative timers that generate an event after a |
921 | <p>Timer watchers are simple relative timers that generate an event after a |
803 | given time, and optionally repeating in regular intervals after that.</p> |
922 | given time, and optionally repeating in regular intervals after that.</p> |
804 | <p>The timers are based on real time, that is, if you register an event that |
923 | <p>The timers are based on real time, that is, if you register an event that |
805 | times out after an hour and you reset your system clock to last years |
924 | times out after an hour and you reset your system clock to last years |
… | |
… | |
837 | repeating. The exact semantics are:</p> |
956 | repeating. The exact semantics are:</p> |
838 | <p>If the timer is started but nonrepeating, stop it.</p> |
957 | <p>If the timer is started but nonrepeating, stop it.</p> |
839 | <p>If the timer is repeating, either start it if necessary (with the repeat |
958 | <p>If the timer is repeating, either start it if necessary (with the repeat |
840 | value), or reset the running timer to the repeat value.</p> |
959 | value), or reset the running timer to the repeat value.</p> |
841 | <p>This sounds a bit complicated, but here is a useful and typical |
960 | <p>This sounds a bit complicated, but here is a useful and typical |
842 | example: Imagine you have a tcp connection and you want a so-called idle |
961 | example: Imagine you have a tcp connection and you want a so-called |
843 | timeout, that is, you want to be called when there have been, say, 60 |
962 | idle timeout, that is, you want to be called when there have been, |
844 | seconds of inactivity on the socket. The easiest way to do this is to |
963 | say, 60 seconds of inactivity on the socket. The easiest way to do |
845 | configure an <code>ev_timer</code> with after=repeat=60 and calling ev_timer_again each |
964 | this is to configure an <code>ev_timer</code> with <code>after</code>=<code>repeat</code>=<code>60</code> and calling |
846 | time you successfully read or write some data. If you go into an idle |
965 | <code>ev_timer_again</code> each time you successfully read or write some data. If |
847 | state where you do not expect data to travel on the socket, you can stop |
966 | you go into an idle state where you do not expect data to travel on the |
848 | the timer, and again will automatically restart it if need be.</p> |
967 | socket, you can stop the timer, and again will automatically restart it if |
|
|
968 | need be.</p> |
|
|
969 | <p>You can also ignore the <code>after</code> value and <code>ev_timer_start</code> altogether |
|
|
970 | and only ever use the <code>repeat</code> value:</p> |
|
|
971 | <pre> ev_timer_init (timer, callback, 0., 5.); |
|
|
972 | ev_timer_again (loop, timer); |
|
|
973 | ... |
|
|
974 | timer->again = 17.; |
|
|
975 | ev_timer_again (loop, timer); |
|
|
976 | ... |
|
|
977 | timer->again = 10.; |
|
|
978 | ev_timer_again (loop, timer); |
|
|
979 | |
|
|
980 | </pre> |
|
|
981 | <p>This is more efficient then stopping/starting the timer eahc time you want |
|
|
982 | to modify its timeout value.</p> |
|
|
983 | </dd> |
|
|
984 | <dt>ev_tstamp repeat [read-write]</dt> |
|
|
985 | <dd> |
|
|
986 | <p>The current <code>repeat</code> value. Will be used each time the watcher times out |
|
|
987 | or <code>ev_timer_again</code> is called and determines the next timeout (if any), |
|
|
988 | which is also when any modifications are taken into account.</p> |
849 | </dd> |
989 | </dd> |
850 | </dl> |
990 | </dl> |
851 | <p>Example: create a timer that fires after 60 seconds.</p> |
991 | <p>Example: Create a timer that fires after 60 seconds.</p> |
852 | <pre> static void |
992 | <pre> static void |
853 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
993 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
854 | { |
994 | { |
855 | .. one minute over, w is actually stopped right here |
995 | .. one minute over, w is actually stopped right here |
856 | } |
996 | } |
… | |
… | |
858 | struct ev_timer mytimer; |
998 | struct ev_timer mytimer; |
859 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
999 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
860 | ev_timer_start (loop, &mytimer); |
1000 | ev_timer_start (loop, &mytimer); |
861 | |
1001 | |
862 | </pre> |
1002 | </pre> |
863 | <p>Example: create a timeout timer that times out after 10 seconds of |
1003 | <p>Example: Create a timeout timer that times out after 10 seconds of |
864 | inactivity.</p> |
1004 | inactivity.</p> |
865 | <pre> static void |
1005 | <pre> static void |
866 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1006 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
867 | { |
1007 | { |
868 | .. ten seconds without any activity |
1008 | .. ten seconds without any activity |
… | |
… | |
881 | |
1021 | |
882 | |
1022 | |
883 | </pre> |
1023 | </pre> |
884 | |
1024 | |
885 | </div> |
1025 | </div> |
886 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron</h2> |
1026 | <h2 id="code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</h2> |
887 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
1027 | <div id="code_ev_periodic_code_to_cron_or_not-2"> |
888 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
1028 | <p>Periodic watchers are also timers of a kind, but they are very versatile |
889 | (and unfortunately a bit complex).</p> |
1029 | (and unfortunately a bit complex).</p> |
890 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
1030 | <p>Unlike <code>ev_timer</code>'s, they are not based on real time (or relative time) |
891 | but on wallclock time (absolute time). You can tell a periodic watcher |
1031 | but on wallclock time (absolute time). You can tell a periodic watcher |
… | |
… | |
971 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
1111 | <p>Simply stops and restarts the periodic watcher again. This is only useful |
972 | when you changed some parameters or the reschedule callback would return |
1112 | when you changed some parameters or the reschedule callback would return |
973 | a different time than the last time it was called (e.g. in a crond like |
1113 | a different time than the last time it was called (e.g. in a crond like |
974 | program when the crontabs have changed).</p> |
1114 | program when the crontabs have changed).</p> |
975 | </dd> |
1115 | </dd> |
|
|
1116 | <dt>ev_tstamp interval [read-write]</dt> |
|
|
1117 | <dd> |
|
|
1118 | <p>The current interval value. Can be modified any time, but changes only |
|
|
1119 | take effect when the periodic timer fires or <code>ev_periodic_again</code> is being |
|
|
1120 | called.</p> |
|
|
1121 | </dd> |
|
|
1122 | <dt>ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]</dt> |
|
|
1123 | <dd> |
|
|
1124 | <p>The current reschedule callback, or <code>0</code>, if this functionality is |
|
|
1125 | switched off. Can be changed any time, but changes only take effect when |
|
|
1126 | the periodic timer fires or <code>ev_periodic_again</code> is being called.</p> |
|
|
1127 | </dd> |
976 | </dl> |
1128 | </dl> |
977 | <p>Example: call a callback every hour, or, more precisely, whenever the |
1129 | <p>Example: Call a callback every hour, or, more precisely, whenever the |
978 | system clock is divisible by 3600. The callback invocation times have |
1130 | system clock is divisible by 3600. The callback invocation times have |
979 | potentially a lot of jittering, but good long-term stability.</p> |
1131 | potentially a lot of jittering, but good long-term stability.</p> |
980 | <pre> static void |
1132 | <pre> static void |
981 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1133 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
982 | { |
1134 | { |
… | |
… | |
986 | struct ev_periodic hourly_tick; |
1138 | struct ev_periodic hourly_tick; |
987 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1139 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
988 | ev_periodic_start (loop, &hourly_tick); |
1140 | ev_periodic_start (loop, &hourly_tick); |
989 | |
1141 | |
990 | </pre> |
1142 | </pre> |
991 | <p>Example: the same as above, but use a reschedule callback to do it:</p> |
1143 | <p>Example: The same as above, but use a reschedule callback to do it:</p> |
992 | <pre> #include <math.h> |
1144 | <pre> #include <math.h> |
993 | |
1145 | |
994 | static ev_tstamp |
1146 | static ev_tstamp |
995 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1147 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
996 | { |
1148 | { |
… | |
… | |
998 | } |
1150 | } |
999 | |
1151 | |
1000 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1152 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1001 | |
1153 | |
1002 | </pre> |
1154 | </pre> |
1003 | <p>Example: call a callback every hour, starting now:</p> |
1155 | <p>Example: Call a callback every hour, starting now:</p> |
1004 | <pre> struct ev_periodic hourly_tick; |
1156 | <pre> struct ev_periodic hourly_tick; |
1005 | ev_periodic_init (&hourly_tick, clock_cb, |
1157 | ev_periodic_init (&hourly_tick, clock_cb, |
1006 | fmod (ev_now (loop), 3600.), 3600., 0); |
1158 | fmod (ev_now (loop), 3600.), 3600., 0); |
1007 | ev_periodic_start (loop, &hourly_tick); |
1159 | ev_periodic_start (loop, &hourly_tick); |
1008 | |
1160 | |
… | |
… | |
1010 | |
1162 | |
1011 | |
1163 | |
1012 | </pre> |
1164 | </pre> |
1013 | |
1165 | |
1014 | </div> |
1166 | </div> |
1015 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled</h2> |
1167 | <h2 id="code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</h2> |
1016 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
1168 | <div id="code_ev_signal_code_signal_me_when_a-2"> |
1017 | <p>Signal watchers will trigger an event when the process receives a specific |
1169 | <p>Signal watchers will trigger an event when the process receives a specific |
1018 | signal one or more times. Even though signals are very asynchronous, libev |
1170 | signal one or more times. Even though signals are very asynchronous, libev |
1019 | will try it's best to deliver signals synchronously, i.e. as part of the |
1171 | will try it's best to deliver signals synchronously, i.e. as part of the |
1020 | normal event processing, like any other event.</p> |
1172 | normal event processing, like any other event.</p> |
… | |
… | |
1029 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1181 | <dt>ev_signal_set (ev_signal *, int signum)</dt> |
1030 | <dd> |
1182 | <dd> |
1031 | <p>Configures the watcher to trigger on the given signal number (usually one |
1183 | <p>Configures the watcher to trigger on the given signal number (usually one |
1032 | of the <code>SIGxxx</code> constants).</p> |
1184 | of the <code>SIGxxx</code> constants).</p> |
1033 | </dd> |
1185 | </dd> |
|
|
1186 | <dt>int signum [read-only]</dt> |
|
|
1187 | <dd> |
|
|
1188 | <p>The signal the watcher watches out for.</p> |
|
|
1189 | </dd> |
1034 | </dl> |
1190 | </dl> |
1035 | |
1191 | |
1036 | |
1192 | |
1037 | |
1193 | |
1038 | |
1194 | |
1039 | |
1195 | |
1040 | </div> |
1196 | </div> |
1041 | <h2 id="code_ev_child_code_wait_for_pid_stat"><code>ev_child</code> - wait for pid status changes</h2> |
1197 | <h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2> |
1042 | <div id="code_ev_child_code_wait_for_pid_stat-2"> |
1198 | <div id="code_ev_child_code_watch_out_for_pro-2"> |
1043 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
1199 | <p>Child watchers trigger when your process receives a SIGCHLD in response to |
1044 | some child status changes (most typically when a child of yours dies).</p> |
1200 | some child status changes (most typically when a child of yours dies).</p> |
1045 | <dl> |
1201 | <dl> |
1046 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
1202 | <dt>ev_child_init (ev_child *, callback, int pid)</dt> |
1047 | <dt>ev_child_set (ev_child *, int pid)</dt> |
1203 | <dt>ev_child_set (ev_child *, int pid)</dt> |
… | |
… | |
1051 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1207 | at the <code>rstatus</code> member of the <code>ev_child</code> watcher structure to see |
1052 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1208 | the status word (use the macros from <code>sys/wait.h</code> and see your systems |
1053 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1209 | <code>waitpid</code> documentation). The <code>rpid</code> member contains the pid of the |
1054 | process causing the status change.</p> |
1210 | process causing the status change.</p> |
1055 | </dd> |
1211 | </dd> |
|
|
1212 | <dt>int pid [read-only]</dt> |
|
|
1213 | <dd> |
|
|
1214 | <p>The process id this watcher watches out for, or <code>0</code>, meaning any process id.</p> |
|
|
1215 | </dd> |
|
|
1216 | <dt>int rpid [read-write]</dt> |
|
|
1217 | <dd> |
|
|
1218 | <p>The process id that detected a status change.</p> |
|
|
1219 | </dd> |
|
|
1220 | <dt>int rstatus [read-write]</dt> |
|
|
1221 | <dd> |
|
|
1222 | <p>The process exit/trace status caused by <code>rpid</code> (see your systems |
|
|
1223 | <code>waitpid</code> and <code>sys/wait.h</code> documentation for details).</p> |
|
|
1224 | </dd> |
1056 | </dl> |
1225 | </dl> |
1057 | <p>Example: try to exit cleanly on SIGINT and SIGTERM.</p> |
1226 | <p>Example: Try to exit cleanly on SIGINT and SIGTERM.</p> |
1058 | <pre> static void |
1227 | <pre> static void |
1059 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1228 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1060 | { |
1229 | { |
1061 | ev_unloop (loop, EVUNLOOP_ALL); |
1230 | ev_unloop (loop, EVUNLOOP_ALL); |
1062 | } |
1231 | } |
… | |
… | |
1069 | |
1238 | |
1070 | |
1239 | |
1071 | </pre> |
1240 | </pre> |
1072 | |
1241 | |
1073 | </div> |
1242 | </div> |
|
|
1243 | <h2 id="code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</h2> |
|
|
1244 | <div id="code_ev_stat_code_did_the_file_attri-2"> |
|
|
1245 | <p>This watches a filesystem path for attribute changes. That is, it calls |
|
|
1246 | <code>stat</code> regularly (or when the OS says it changed) and sees if it changed |
|
|
1247 | compared to the last time, invoking the callback if it did.</p> |
|
|
1248 | <p>The path does not need to exist: changing from "path exists" to "path does |
|
|
1249 | not exist" is a status change like any other. The condition "path does |
|
|
1250 | not exist" is signified by the <code>st_nlink</code> field being zero (which is |
|
|
1251 | otherwise always forced to be at least one) and all the other fields of |
|
|
1252 | the stat buffer having unspecified contents.</p> |
|
|
1253 | <p>Since there is no standard to do this, the portable implementation simply |
|
|
1254 | calls <code>stat (2)</code> regularly on the path to see if it changed somehow. You |
|
|
1255 | can specify a recommended polling interval for this case. If you specify |
|
|
1256 | a polling interval of <code>0</code> (highly recommended!) then a <i>suitable, |
|
|
1257 | unspecified default</i> value will be used (which you can expect to be around |
|
|
1258 | five seconds, although this might change dynamically). Libev will also |
|
|
1259 | impose a minimum interval which is currently around <code>0.1</code>, but thats |
|
|
1260 | usually overkill.</p> |
|
|
1261 | <p>This watcher type is not meant for massive numbers of stat watchers, |
|
|
1262 | as even with OS-supported change notifications, this can be |
|
|
1263 | resource-intensive.</p> |
|
|
1264 | <p>At the time of this writing, only the Linux inotify interface is |
|
|
1265 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1266 | reader). Inotify will be used to give hints only and should not change the |
|
|
1267 | semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs |
|
|
1268 | to fall back to regular polling again even with inotify, but changes are |
|
|
1269 | usually detected immediately, and if the file exists there will be no |
|
|
1270 | polling.</p> |
|
|
1271 | <dl> |
|
|
1272 | <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> |
|
|
1273 | <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> |
|
|
1274 | <dd> |
|
|
1275 | <p>Configures the watcher to wait for status changes of the given |
|
|
1276 | <code>path</code>. The <code>interval</code> is a hint on how quickly a change is expected to |
|
|
1277 | be detected and should normally be specified as <code>0</code> to let libev choose |
|
|
1278 | a suitable value. The memory pointed to by <code>path</code> must point to the same |
|
|
1279 | path for as long as the watcher is active.</p> |
|
|
1280 | <p>The callback will be receive <code>EV_STAT</code> when a change was detected, |
|
|
1281 | relative to the attributes at the time the watcher was started (or the |
|
|
1282 | last change was detected).</p> |
|
|
1283 | </dd> |
|
|
1284 | <dt>ev_stat_stat (ev_stat *)</dt> |
|
|
1285 | <dd> |
|
|
1286 | <p>Updates the stat buffer immediately with new values. If you change the |
|
|
1287 | watched path in your callback, you could call this fucntion to avoid |
|
|
1288 | detecting this change (while introducing a race condition). Can also be |
|
|
1289 | useful simply to find out the new values.</p> |
|
|
1290 | </dd> |
|
|
1291 | <dt>ev_statdata attr [read-only]</dt> |
|
|
1292 | <dd> |
|
|
1293 | <p>The most-recently detected attributes of the file. Although the type is of |
|
|
1294 | <code>ev_statdata</code>, this is usually the (or one of the) <code>struct stat</code> types |
|
|
1295 | suitable for your system. If the <code>st_nlink</code> member is <code>0</code>, then there |
|
|
1296 | was some error while <code>stat</code>ing the file.</p> |
|
|
1297 | </dd> |
|
|
1298 | <dt>ev_statdata prev [read-only]</dt> |
|
|
1299 | <dd> |
|
|
1300 | <p>The previous attributes of the file. The callback gets invoked whenever |
|
|
1301 | <code>prev</code> != <code>attr</code>.</p> |
|
|
1302 | </dd> |
|
|
1303 | <dt>ev_tstamp interval [read-only]</dt> |
|
|
1304 | <dd> |
|
|
1305 | <p>The specified interval.</p> |
|
|
1306 | </dd> |
|
|
1307 | <dt>const char *path [read-only]</dt> |
|
|
1308 | <dd> |
|
|
1309 | <p>The filesystem path that is being watched.</p> |
|
|
1310 | </dd> |
|
|
1311 | </dl> |
|
|
1312 | <p>Example: Watch <code>/etc/passwd</code> for attribute changes.</p> |
|
|
1313 | <pre> static void |
|
|
1314 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1315 | { |
|
|
1316 | /* /etc/passwd changed in some way */ |
|
|
1317 | if (w->attr.st_nlink) |
|
|
1318 | { |
|
|
1319 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1320 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1321 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1322 | } |
|
|
1323 | else |
|
|
1324 | /* you shalt not abuse printf for puts */ |
|
|
1325 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1326 | "if this is windows, they already arrived\n"); |
|
|
1327 | } |
|
|
1328 | |
|
|
1329 | ... |
|
|
1330 | ev_stat passwd; |
|
|
1331 | |
|
|
1332 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1333 | ev_stat_start (loop, &passwd); |
|
|
1334 | |
|
|
1335 | |
|
|
1336 | |
|
|
1337 | |
|
|
1338 | </pre> |
|
|
1339 | |
|
|
1340 | </div> |
1074 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do</h2> |
1341 | <h2 id="code_ev_idle_code_when_you_ve_got_no"><code>ev_idle</code> - when you've got nothing better to do...</h2> |
1075 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1342 | <div id="code_ev_idle_code_when_you_ve_got_no-2"> |
1076 | <p>Idle watchers trigger events when there are no other events are pending |
1343 | <p>Idle watchers trigger events when there are no other events are pending |
1077 | (prepare, check and other idle watchers do not count). That is, as long |
1344 | (prepare, check and other idle watchers do not count). That is, as long |
1078 | as your process is busy handling sockets or timeouts (or even signals, |
1345 | as your process is busy handling sockets or timeouts (or even signals, |
1079 | imagine) it will not be triggered. But when your process is idle all idle |
1346 | imagine) it will not be triggered. But when your process is idle all idle |
… | |
… | |
1092 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1359 | <p>Initialises and configures the idle watcher - it has no parameters of any |
1093 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1360 | kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, |
1094 | believe me.</p> |
1361 | believe me.</p> |
1095 | </dd> |
1362 | </dd> |
1096 | </dl> |
1363 | </dl> |
1097 | <p>Example: dynamically allocate an <code>ev_idle</code>, start it, and in the |
1364 | <p>Example: Dynamically allocate an <code>ev_idle</code> watcher, start it, and in the |
1098 | callback, free it. Alos, use no error checking, as usual.</p> |
1365 | callback, free it. Also, use no error checking, as usual.</p> |
1099 | <pre> static void |
1366 | <pre> static void |
1100 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1367 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1101 | { |
1368 | { |
1102 | free (w); |
1369 | free (w); |
1103 | // now do something you wanted to do when the program has |
1370 | // now do something you wanted to do when the program has |
… | |
… | |
1112 | |
1379 | |
1113 | |
1380 | |
1114 | </pre> |
1381 | </pre> |
1115 | |
1382 | |
1116 | </div> |
1383 | </div> |
1117 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop</h2> |
1384 | <h2 id="code_ev_prepare_code_and_code_ev_che"><code>ev_prepare</code> and <code>ev_check</code> - customise your event loop!</h2> |
1118 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1385 | <div id="code_ev_prepare_code_and_code_ev_che-2"> |
1119 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1386 | <p>Prepare and check watchers are usually (but not always) used in tandem: |
1120 | prepare watchers get invoked before the process blocks and check watchers |
1387 | prepare watchers get invoked before the process blocks and check watchers |
1121 | afterwards.</p> |
1388 | afterwards.</p> |
|
|
1389 | <p>You <i>must not</i> call <code>ev_loop</code> or similar functions that enter |
|
|
1390 | the current event loop from either <code>ev_prepare</code> or <code>ev_check</code> |
|
|
1391 | watchers. Other loops than the current one are fine, however. The |
|
|
1392 | rationale behind this is that you do not need to check for recursion in |
|
|
1393 | those watchers, i.e. the sequence will always be <code>ev_prepare</code>, blocking, |
|
|
1394 | <code>ev_check</code> so if you have one watcher of each kind they will always be |
|
|
1395 | called in pairs bracketing the blocking call.</p> |
1122 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1396 | <p>Their main purpose is to integrate other event mechanisms into libev and |
1123 | their use is somewhat advanced. This could be used, for example, to track |
1397 | their use is somewhat advanced. This could be used, for example, to track |
1124 | variable changes, implement your own watchers, integrate net-snmp or a |
1398 | variable changes, implement your own watchers, integrate net-snmp or a |
1125 | coroutine library and lots more.</p> |
1399 | coroutine library and lots more. They are also occasionally useful if |
|
|
1400 | you cache some data and want to flush it before blocking (for example, |
|
|
1401 | in X programs you might want to do an <code>XFlush ()</code> in an <code>ev_prepare</code> |
|
|
1402 | watcher).</p> |
1126 | <p>This is done by examining in each prepare call which file descriptors need |
1403 | <p>This is done by examining in each prepare call which file descriptors need |
1127 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1404 | to be watched by the other library, registering <code>ev_io</code> watchers for |
1128 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1405 | them and starting an <code>ev_timer</code> watcher for any timeouts (many libraries |
1129 | provide just this functionality). Then, in the check watcher you check for |
1406 | provide just this functionality). Then, in the check watcher you check for |
1130 | any events that occured (by checking the pending status of all watchers |
1407 | any events that occured (by checking the pending status of all watchers |
… | |
… | |
1146 | <p>Initialises and configures the prepare or check watcher - they have no |
1423 | <p>Initialises and configures the prepare or check watcher - they have no |
1147 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1424 | parameters of any kind. There are <code>ev_prepare_set</code> and <code>ev_check_set</code> |
1148 | macros, but using them is utterly, utterly and completely pointless.</p> |
1425 | macros, but using them is utterly, utterly and completely pointless.</p> |
1149 | </dd> |
1426 | </dd> |
1150 | </dl> |
1427 | </dl> |
1151 | <p>Example: *TODO*.</p> |
1428 | <p>Example: To include a library such as adns, you would add IO watchers |
|
|
1429 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1430 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1431 | pseudo-code only of course:</p> |
|
|
1432 | <pre> static ev_io iow [nfd]; |
|
|
1433 | static ev_timer tw; |
1152 | |
1434 | |
|
|
1435 | static void |
|
|
1436 | io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1437 | { |
|
|
1438 | // set the relevant poll flags |
|
|
1439 | // could also call adns_processreadable etc. here |
|
|
1440 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1441 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1442 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1443 | } |
1153 | |
1444 | |
|
|
1445 | // create io watchers for each fd and a timer before blocking |
|
|
1446 | static void |
|
|
1447 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1448 | { |
|
|
1449 | int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1450 | // actual code will need to loop here and realloc etc. |
|
|
1451 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1154 | |
1452 | |
|
|
1453 | /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1454 | ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1455 | ev_timer_start (loop, &tw); |
1155 | |
1456 | |
|
|
1457 | // create on ev_io per pollfd |
|
|
1458 | for (int i = 0; i < nfd; ++i) |
|
|
1459 | { |
|
|
1460 | ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1461 | ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1462 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1156 | |
1463 | |
|
|
1464 | fds [i].revents = 0; |
|
|
1465 | iow [i].data = fds + i; |
|
|
1466 | ev_io_start (loop, iow + i); |
|
|
1467 | } |
|
|
1468 | } |
|
|
1469 | |
|
|
1470 | // stop all watchers after blocking |
|
|
1471 | static void |
|
|
1472 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1473 | { |
|
|
1474 | ev_timer_stop (loop, &tw); |
|
|
1475 | |
|
|
1476 | for (int i = 0; i < nfd; ++i) |
|
|
1477 | ev_io_stop (loop, iow + i); |
|
|
1478 | |
|
|
1479 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1480 | } |
|
|
1481 | |
|
|
1482 | |
|
|
1483 | |
|
|
1484 | |
|
|
1485 | </pre> |
|
|
1486 | |
1157 | </div> |
1487 | </div> |
1158 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough</h2> |
1488 | <h2 id="code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</h2> |
1159 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1489 | <div id="code_ev_embed_code_when_one_backend_-2"> |
1160 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1490 | <p>This is a rather advanced watcher type that lets you embed one event loop |
1161 | into another (currently only <code>ev_io</code> events are supported in the embedded |
1491 | into another (currently only <code>ev_io</code> events are supported in the embedded |
1162 | loop, other types of watchers might be handled in a delayed or incorrect |
1492 | loop, other types of watchers might be handled in a delayed or incorrect |
1163 | fashion and must not be used).</p> |
1493 | fashion and must not be used).</p> |
… | |
… | |
1231 | <dd> |
1561 | <dd> |
1232 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1562 | <p>Make a single, non-blocking sweep over the embedded loop. This works |
1233 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1563 | similarly to <code>ev_loop (embedded_loop, EVLOOP_NONBLOCK)</code>, but in the most |
1234 | apropriate way for embedded loops.</p> |
1564 | apropriate way for embedded loops.</p> |
1235 | </dd> |
1565 | </dd> |
|
|
1566 | <dt>struct ev_loop *loop [read-only]</dt> |
|
|
1567 | <dd> |
|
|
1568 | <p>The embedded event loop.</p> |
|
|
1569 | </dd> |
1236 | </dl> |
1570 | </dl> |
1237 | |
1571 | |
1238 | |
1572 | |
1239 | |
1573 | |
1240 | |
1574 | |
1241 | |
1575 | |
1242 | </div> |
1576 | </div> |
1243 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1577 | <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> |
|
|
1578 | <div id="code_ev_fork_code_the_audacity_to_re-2"> |
|
|
1579 | <p>Fork watchers are called when a <code>fork ()</code> was detected (usually because |
|
|
1580 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1581 | <code>ev_default_fork</code> or <code>ev_loop_fork</code>). The invocation is done before the |
|
|
1582 | event loop blocks next and before <code>ev_check</code> watchers are being called, |
|
|
1583 | and only in the child after the fork. If whoever good citizen calling |
|
|
1584 | <code>ev_default_fork</code> cheats and calls it in the wrong process, the fork |
|
|
1585 | handlers will be invoked, too, of course.</p> |
|
|
1586 | <dl> |
|
|
1587 | <dt>ev_fork_init (ev_signal *, callback)</dt> |
|
|
1588 | <dd> |
|
|
1589 | <p>Initialises and configures the fork watcher - it has no parameters of any |
|
|
1590 | kind. There is a <code>ev_fork_set</code> macro, but using it is utterly pointless, |
|
|
1591 | believe me.</p> |
|
|
1592 | </dd> |
|
|
1593 | </dl> |
|
|
1594 | |
|
|
1595 | |
|
|
1596 | |
|
|
1597 | |
|
|
1598 | |
|
|
1599 | </div> |
|
|
1600 | <h1 id="OTHER_FUNCTIONS">OTHER FUNCTIONS</h1> |
1244 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1601 | <div id="OTHER_FUNCTIONS_CONTENT"> |
1245 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1602 | <p>There are some other functions of possible interest. Described. Here. Now.</p> |
1246 | <dl> |
1603 | <dl> |
1247 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1604 | <dt>ev_once (loop, int fd, int events, ev_tstamp timeout, callback)</dt> |
1248 | <dd> |
1605 | <dd> |
… | |
… | |
1295 | |
1652 | |
1296 | |
1653 | |
1297 | |
1654 | |
1298 | |
1655 | |
1299 | </div> |
1656 | </div> |
1300 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1657 | <h1 id="LIBEVENT_EMULATION">LIBEVENT EMULATION</h1> |
1301 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1658 | <div id="LIBEVENT_EMULATION_CONTENT"> |
1302 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1659 | <p>Libev offers a compatibility emulation layer for libevent. It cannot |
1303 | emulate the internals of libevent, so here are some usage hints:</p> |
1660 | emulate the internals of libevent, so here are some usage hints:</p> |
1304 | <dl> |
1661 | <dl> |
1305 | <dt>* Use it by including <event.h>, as usual.</dt> |
1662 | <dt>* Use it by including <event.h>, as usual.</dt> |
… | |
… | |
1315 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1672 | <dt>* The libev emulation is <i>not</i> ABI compatible to libevent, you need |
1316 | to use the libev header file and library.</dt> |
1673 | to use the libev header file and library.</dt> |
1317 | </dl> |
1674 | </dl> |
1318 | |
1675 | |
1319 | </div> |
1676 | </div> |
1320 | <h1 id="C_SUPPORT">C++ SUPPORT</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1677 | <h1 id="C_SUPPORT">C++ SUPPORT</h1> |
1321 | <div id="C_SUPPORT_CONTENT"> |
1678 | <div id="C_SUPPORT_CONTENT"> |
1322 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1679 | <p>Libev comes with some simplistic wrapper classes for C++ that mainly allow |
1323 | you to use some convinience methods to start/stop watchers and also change |
1680 | you to use some convinience methods to start/stop watchers and also change |
1324 | the callback model to a model using method callbacks on objects.</p> |
1681 | the callback model to a model using method callbacks on objects.</p> |
1325 | <p>To use it,</p> |
1682 | <p>To use it,</p> |
… | |
… | |
1389 | </dd> |
1746 | </dd> |
1390 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1747 | <dt>w->sweep () <code>ev::embed</code> only</dt> |
1391 | <dd> |
1748 | <dd> |
1392 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1749 | <p>Invokes <code>ev_embed_sweep</code>.</p> |
1393 | </dd> |
1750 | </dd> |
|
|
1751 | <dt>w->update () <code>ev::stat</code> only</dt> |
|
|
1752 | <dd> |
|
|
1753 | <p>Invokes <code>ev_stat_stat</code>.</p> |
|
|
1754 | </dd> |
1394 | </dl> |
1755 | </dl> |
1395 | </p> |
1756 | </p> |
1396 | </dd> |
1757 | </dd> |
1397 | </dl> |
1758 | </dl> |
1398 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
1759 | <p>Example: Define a class with an IO and idle watcher, start one of them in |
… | |
… | |
1410 | idle (this, &myclass::idle_cb) |
1771 | idle (this, &myclass::idle_cb) |
1411 | { |
1772 | { |
1412 | io.start (fd, ev::READ); |
1773 | io.start (fd, ev::READ); |
1413 | } |
1774 | } |
1414 | |
1775 | |
1415 | </pre> |
|
|
1416 | |
1776 | |
|
|
1777 | |
|
|
1778 | |
|
|
1779 | </pre> |
|
|
1780 | |
1417 | </div> |
1781 | </div> |
1418 | <h1 id="EMBEDDING">EMBEDDING</h1><p><a href="#TOP" class="toplink">Top</a></p> |
1782 | <h1 id="MACRO_MAGIC">MACRO MAGIC</h1> |
|
|
1783 | <div id="MACRO_MAGIC_CONTENT"> |
|
|
1784 | <p>Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1785 | <code>EV_MULTIPLICITY</code>. This option determines wether (most) functions and |
|
|
1786 | callbacks have an initial <code>struct ev_loop *</code> argument.</p> |
|
|
1787 | <p>To make it easier to write programs that cope with either variant, the |
|
|
1788 | following macros are defined:</p> |
|
|
1789 | <dl> |
|
|
1790 | <dt><code>EV_A</code>, <code>EV_A_</code></dt> |
|
|
1791 | <dd> |
|
|
1792 | <p>This provides the loop <i>argument</i> for functions, if one is required ("ev |
|
|
1793 | loop argument"). The <code>EV_A</code> form is used when this is the sole argument, |
|
|
1794 | <code>EV_A_</code> is used when other arguments are following. Example:</p> |
|
|
1795 | <pre> ev_unref (EV_A); |
|
|
1796 | ev_timer_add (EV_A_ watcher); |
|
|
1797 | ev_loop (EV_A_ 0); |
|
|
1798 | |
|
|
1799 | </pre> |
|
|
1800 | <p>It assumes the variable <code>loop</code> of type <code>struct ev_loop *</code> is in scope, |
|
|
1801 | which is often provided by the following macro.</p> |
|
|
1802 | </dd> |
|
|
1803 | <dt><code>EV_P</code>, <code>EV_P_</code></dt> |
|
|
1804 | <dd> |
|
|
1805 | <p>This provides the loop <i>parameter</i> for functions, if one is required ("ev |
|
|
1806 | loop parameter"). The <code>EV_P</code> form is used when this is the sole parameter, |
|
|
1807 | <code>EV_P_</code> is used when other parameters are following. Example:</p> |
|
|
1808 | <pre> // this is how ev_unref is being declared |
|
|
1809 | static void ev_unref (EV_P); |
|
|
1810 | |
|
|
1811 | // this is how you can declare your typical callback |
|
|
1812 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1813 | |
|
|
1814 | </pre> |
|
|
1815 | <p>It declares a parameter <code>loop</code> of type <code>struct ev_loop *</code>, quite |
|
|
1816 | suitable for use with <code>EV_A</code>.</p> |
|
|
1817 | </dd> |
|
|
1818 | <dt><code>EV_DEFAULT</code>, <code>EV_DEFAULT_</code></dt> |
|
|
1819 | <dd> |
|
|
1820 | <p>Similar to the other two macros, this gives you the value of the default |
|
|
1821 | loop, if multiple loops are supported ("ev loop default").</p> |
|
|
1822 | </dd> |
|
|
1823 | </dl> |
|
|
1824 | <p>Example: Declare and initialise a check watcher, working regardless of |
|
|
1825 | wether multiple loops are supported or not.</p> |
|
|
1826 | <pre> static void |
|
|
1827 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1828 | { |
|
|
1829 | ev_check_stop (EV_A_ w); |
|
|
1830 | } |
|
|
1831 | |
|
|
1832 | ev_check check; |
|
|
1833 | ev_check_init (&check, check_cb); |
|
|
1834 | ev_check_start (EV_DEFAULT_ &check); |
|
|
1835 | ev_loop (EV_DEFAULT_ 0); |
|
|
1836 | |
|
|
1837 | |
|
|
1838 | |
|
|
1839 | |
|
|
1840 | </pre> |
|
|
1841 | |
|
|
1842 | </div> |
|
|
1843 | <h1 id="EMBEDDING">EMBEDDING</h1> |
1419 | <div id="EMBEDDING_CONTENT"> |
1844 | <div id="EMBEDDING_CONTENT"> |
1420 | <p>Libev can (and often is) directly embedded into host |
1845 | <p>Libev can (and often is) directly embedded into host |
1421 | applications. Examples of applications that embed it include the Deliantra |
1846 | applications. Examples of applications that embed it include the Deliantra |
1422 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1847 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1423 | and rxvt-unicode.</p> |
1848 | and rxvt-unicode.</p> |
… | |
… | |
1460 | ev_vars.h |
1885 | ev_vars.h |
1461 | ev_wrap.h |
1886 | ev_wrap.h |
1462 | |
1887 | |
1463 | ev_win32.c required on win32 platforms only |
1888 | ev_win32.c required on win32 platforms only |
1464 | |
1889 | |
1465 | ev_select.c only when select backend is enabled (which is is by default) |
1890 | ev_select.c only when select backend is enabled (which is by default) |
1466 | ev_poll.c only when poll backend is enabled (disabled by default) |
1891 | ev_poll.c only when poll backend is enabled (disabled by default) |
1467 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1892 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1468 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1893 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1469 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1894 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1470 | |
1895 | |
1471 | </pre> |
1896 | </pre> |
1472 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
1897 | <p><cite>ev.c</cite> includes the backend files directly when enabled, so you only need |
1473 | to compile a single file.</p> |
1898 | to compile this single file.</p> |
1474 | |
1899 | |
1475 | </div> |
1900 | </div> |
1476 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
1901 | <h3 id="LIBEVENT_COMPATIBILITY_API">LIBEVENT COMPATIBILITY API</h3> |
1477 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
1902 | <div id="LIBEVENT_COMPATIBILITY_API_CONTENT"> |
1478 | <p>To include the libevent compatibility API, also include:</p> |
1903 | <p>To include the libevent compatibility API, also include:</p> |
… | |
… | |
1493 | </div> |
1918 | </div> |
1494 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
1919 | <h3 id="AUTOCONF_SUPPORT">AUTOCONF SUPPORT</h3> |
1495 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
1920 | <div id="AUTOCONF_SUPPORT_CONTENT"> |
1496 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
1921 | <p>Instead of using <code>EV_STANDALONE=1</code> and providing your config in |
1497 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
1922 | whatever way you want, you can also <code>m4_include([libev.m4])</code> in your |
1498 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> off. <cite>ev.c</cite> will then include |
1923 | <cite>configure.ac</cite> and leave <code>EV_STANDALONE</code> undefined. <cite>ev.c</cite> will then |
1499 | <cite>config.h</cite> and configure itself accordingly.</p> |
1924 | include <cite>config.h</cite> and configure itself accordingly.</p> |
1500 | <p>For this of course you need the m4 file:</p> |
1925 | <p>For this of course you need the m4 file:</p> |
1501 | <pre> libev.m4 |
1926 | <pre> libev.m4 |
1502 | |
1927 | |
1503 | </pre> |
1928 | </pre> |
1504 | |
1929 | |
… | |
… | |
1583 | otherwise another method will be used as fallback. This is the preferred |
2008 | otherwise another method will be used as fallback. This is the preferred |
1584 | backend for BSD and BSD-like systems, although on most BSDs kqueue only |
2009 | backend for BSD and BSD-like systems, although on most BSDs kqueue only |
1585 | supports some types of fds correctly (the only platform we found that |
2010 | supports some types of fds correctly (the only platform we found that |
1586 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
2011 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
1587 | not be used unless explicitly requested. The best way to use it is to find |
2012 | not be used unless explicitly requested. The best way to use it is to find |
1588 | out wether kqueue supports your type of fd properly and use an embedded |
2013 | out whether kqueue supports your type of fd properly and use an embedded |
1589 | kqueue loop.</p> |
2014 | kqueue loop.</p> |
1590 | </dd> |
2015 | </dd> |
1591 | <dt>EV_USE_PORT</dt> |
2016 | <dt>EV_USE_PORT</dt> |
1592 | <dd> |
2017 | <dd> |
1593 | <p>If defined to be <code>1</code>, libev will compile in support for the Solaris |
2018 | <p>If defined to be <code>1</code>, libev will compile in support for the Solaris |
… | |
… | |
1596 | backend for Solaris 10 systems.</p> |
2021 | backend for Solaris 10 systems.</p> |
1597 | </dd> |
2022 | </dd> |
1598 | <dt>EV_USE_DEVPOLL</dt> |
2023 | <dt>EV_USE_DEVPOLL</dt> |
1599 | <dd> |
2024 | <dd> |
1600 | <p>reserved for future expansion, works like the USE symbols above.</p> |
2025 | <p>reserved for future expansion, works like the USE symbols above.</p> |
|
|
2026 | </dd> |
|
|
2027 | <dt>EV_USE_INOTIFY</dt> |
|
|
2028 | <dd> |
|
|
2029 | <p>If defined to be <code>1</code>, libev will compile in support for the Linux inotify |
|
|
2030 | interface to speed up <code>ev_stat</code> watchers. Its actual availability will |
|
|
2031 | be detected at runtime.</p> |
1601 | </dd> |
2032 | </dd> |
1602 | <dt>EV_H</dt> |
2033 | <dt>EV_H</dt> |
1603 | <dd> |
2034 | <dd> |
1604 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
2035 | <p>The name of the <cite>ev.h</cite> header file used to include it. The default if |
1605 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
2036 | undefined is <code><ev.h></code> in <cite>event.h</cite> and <code>"ev.h"</code> in <cite>ev.c</cite>. This |
… | |
… | |
1629 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
2060 | will have the <code>struct ev_loop *</code> as first argument, and you can create |
1630 | additional independent event loops. Otherwise there will be no support |
2061 | additional independent event loops. Otherwise there will be no support |
1631 | for multiple event loops and there is no first event loop pointer |
2062 | for multiple event loops and there is no first event loop pointer |
1632 | argument. Instead, all functions act on the single default loop.</p> |
2063 | argument. Instead, all functions act on the single default loop.</p> |
1633 | </dd> |
2064 | </dd> |
1634 | <dt>EV_PERIODICS</dt> |
2065 | <dt>EV_PERIODIC_ENABLE</dt> |
1635 | <dd> |
2066 | <dd> |
1636 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported, |
2067 | <p>If undefined or defined to be <code>1</code>, then periodic timers are supported. If |
1637 | otherwise not. This saves a few kb of code.</p> |
2068 | defined to be <code>0</code>, then they are not. Disabling them saves a few kB of |
|
|
2069 | code.</p> |
|
|
2070 | </dd> |
|
|
2071 | <dt>EV_EMBED_ENABLE</dt> |
|
|
2072 | <dd> |
|
|
2073 | <p>If undefined or defined to be <code>1</code>, then embed watchers are supported. If |
|
|
2074 | defined to be <code>0</code>, then they are not.</p> |
|
|
2075 | </dd> |
|
|
2076 | <dt>EV_STAT_ENABLE</dt> |
|
|
2077 | <dd> |
|
|
2078 | <p>If undefined or defined to be <code>1</code>, then stat watchers are supported. If |
|
|
2079 | defined to be <code>0</code>, then they are not.</p> |
|
|
2080 | </dd> |
|
|
2081 | <dt>EV_FORK_ENABLE</dt> |
|
|
2082 | <dd> |
|
|
2083 | <p>If undefined or defined to be <code>1</code>, then fork watchers are supported. If |
|
|
2084 | defined to be <code>0</code>, then they are not.</p> |
|
|
2085 | </dd> |
|
|
2086 | <dt>EV_MINIMAL</dt> |
|
|
2087 | <dd> |
|
|
2088 | <p>If you need to shave off some kilobytes of code at the expense of some |
|
|
2089 | speed, define this symbol to <code>1</code>. Currently only used for gcc to override |
|
|
2090 | some inlining decisions, saves roughly 30% codesize of amd64.</p> |
|
|
2091 | </dd> |
|
|
2092 | <dt>EV_PID_HASHSIZE</dt> |
|
|
2093 | <dd> |
|
|
2094 | <p><code>ev_child</code> watchers use a small hash table to distribute workload by |
|
|
2095 | pid. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), usually more |
|
|
2096 | than enough. If you need to manage thousands of children you might want to |
|
|
2097 | increase this value (<i>must</i> be a power of two).</p> |
|
|
2098 | </dd> |
|
|
2099 | <dt>EV_INOTIFY_HASHSIZE</dt> |
|
|
2100 | <dd> |
|
|
2101 | <p><code>ev_staz</code> watchers use a small hash table to distribute workload by |
|
|
2102 | inotify watch id. The default size is <code>16</code> (or <code>1</code> with <code>EV_MINIMAL</code>), |
|
|
2103 | usually more than enough. If you need to manage thousands of <code>ev_stat</code> |
|
|
2104 | watchers you might want to increase this value (<i>must</i> be a power of |
|
|
2105 | two).</p> |
1638 | </dd> |
2106 | </dd> |
1639 | <dt>EV_COMMON</dt> |
2107 | <dt>EV_COMMON</dt> |
1640 | <dd> |
2108 | <dd> |
1641 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
2109 | <p>By default, all watchers have a <code>void *data</code> member. By redefining |
1642 | this macro to a something else you can include more and other types of |
2110 | this macro to a something else you can include more and other types of |
… | |
… | |
1647 | SV *self; /* contains this struct */ \ |
2115 | SV *self; /* contains this struct */ \ |
1648 | SV *cb_sv, *fh /* note no trailing ";" */ |
2116 | SV *cb_sv, *fh /* note no trailing ";" */ |
1649 | |
2117 | |
1650 | </pre> |
2118 | </pre> |
1651 | </dd> |
2119 | </dd> |
1652 | <dt>EV_CB_DECLARE(type)</dt> |
2120 | <dt>EV_CB_DECLARE (type)</dt> |
1653 | <dt>EV_CB_INVOKE(watcher,revents)</dt> |
2121 | <dt>EV_CB_INVOKE (watcher, revents)</dt> |
1654 | <dt>ev_set_cb(ev,cb)</dt> |
2122 | <dt>ev_set_cb (ev, cb)</dt> |
1655 | <dd> |
2123 | <dd> |
1656 | <p>Can be used to change the callback member declaration in each watcher, |
2124 | <p>Can be used to change the callback member declaration in each watcher, |
1657 | and the way callbacks are invoked and set. Must expand to a struct member |
2125 | and the way callbacks are invoked and set. Must expand to a struct member |
1658 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
2126 | definition and a statement, respectively. See the <cite>ev.v</cite> header file for |
1659 | their default definitions. One possible use for overriding these is to |
2127 | their default definitions. One possible use for overriding these is to |
1660 | avoid the ev_loop pointer as first argument in all cases, or to use method |
2128 | avoid the <code>struct ev_loop *</code> as first argument in all cases, or to use |
1661 | calls instead of plain function calls in C++.</p> |
2129 | method calls instead of plain function calls in C++.</p> |
1662 | |
2130 | |
1663 | </div> |
2131 | </div> |
1664 | <h2 id="EXAMPLES">EXAMPLES</h2> |
2132 | <h2 id="EXAMPLES">EXAMPLES</h2> |
1665 | <div id="EXAMPLES_CONTENT"> |
2133 | <div id="EXAMPLES_CONTENT"> |
1666 | <p>For a real-world example of a program the includes libev |
2134 | <p>For a real-world example of a program the includes libev |
… | |
… | |
1682 | </pre> |
2150 | </pre> |
1683 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
2151 | <p>And a <cite>ev_cpp.C</cite> implementation file that contains libev proper and is compiled:</p> |
1684 | <pre> #include "ev_cpp.h" |
2152 | <pre> #include "ev_cpp.h" |
1685 | #include "ev.c" |
2153 | #include "ev.c" |
1686 | |
2154 | |
1687 | </pre> |
|
|
1688 | |
2155 | |
|
|
2156 | |
|
|
2157 | |
|
|
2158 | </pre> |
|
|
2159 | |
1689 | </div> |
2160 | </div> |
1690 | <h1 id="AUTHOR">AUTHOR</h1><p><a href="#TOP" class="toplink">Top</a></p> |
2161 | <h1 id="COMPLEXITIES">COMPLEXITIES</h1> |
|
|
2162 | <div id="COMPLEXITIES_CONTENT"> |
|
|
2163 | <p>In this section the complexities of (many of) the algorithms used inside |
|
|
2164 | libev will be explained. For complexity discussions about backends see the |
|
|
2165 | documentation for <code>ev_default_init</code>.</p> |
|
|
2166 | <p> |
|
|
2167 | <dl> |
|
|
2168 | <dt>Starting and stopping timer/periodic watchers: O(log skipped_other_timers)</dt> |
|
|
2169 | <dt>Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)</dt> |
|
|
2170 | <dt>Starting io/check/prepare/idle/signal/child watchers: O(1)</dt> |
|
|
2171 | <dt>Stopping check/prepare/idle watchers: O(1)</dt> |
|
|
2172 | <dt>Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))</dt> |
|
|
2173 | <dt>Finding the next timer per loop iteration: O(1)</dt> |
|
|
2174 | <dt>Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)</dt> |
|
|
2175 | <dt>Activating one watcher: O(1)</dt> |
|
|
2176 | </dl> |
|
|
2177 | </p> |
|
|
2178 | |
|
|
2179 | |
|
|
2180 | |
|
|
2181 | |
|
|
2182 | |
|
|
2183 | </div> |
|
|
2184 | <h1 id="AUTHOR">AUTHOR</h1> |
1691 | <div id="AUTHOR_CONTENT"> |
2185 | <div id="AUTHOR_CONTENT"> |
1692 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
2186 | <p>Marc Lehmann <libev@schmorp.de>.</p> |
1693 | |
2187 | |
1694 | </div> |
2188 | </div> |
1695 | </div></body> |
2189 | </div></body> |