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4<head> 4<head>
5 <title>libev</title> 5 <title>libev</title>
6 <meta name="description" content="Pod documentation for libev" /> 6 <meta name="description" content="Pod documentation for libev" />
7 <meta name="inputfile" content="&lt;standard input&gt;" /> 7 <meta name="inputfile" content="&lt;standard input&gt;" />
8 <meta name="outputfile" content="&lt;standard output&gt;" /> 8 <meta name="outputfile" content="&lt;standard output&gt;" />
9 <meta name="created" content="Sat Dec 8 16:30:24 2007" /> 9 <meta name="created" content="Wed Dec 12 18:55:04 2007" />
10 <meta name="generator" content="Pod::Xhtml 1.57" /> 10 <meta name="generator" content="Pod::Xhtml 1.57" />
11<link rel="stylesheet" href="http://res.tst.eu/pod.css"/></head> 11<link rel="stylesheet" href="http://res.tst.eu/pod.css"/></head>
12<body> 12<body>
13<div class="pod"> 13<div class="pod">
14<!-- INDEX START --> 14<!-- INDEX START -->
… …
27<ul><li><a href="#GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</a></li> 27<ul><li><a href="#GENERIC_WATCHER_FUNCTIONS">GENERIC WATCHER FUNCTIONS</a></li>
28<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>
29</ul> 29</ul>
30</li> 30</li>
31<li><a href="#WATCHER_TYPES">WATCHER TYPES</a> 31<li><a href="#WATCHER_TYPES">WATCHER TYPES</a>
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<ul><li><a href="#code_ev_io_code_is_this_file_descrip"><code>ev_io</code> - is this file descriptor readable or writable?</a>
33<ul><li><a href="#The_special_problem_of_disappearing_">The special problem of disappearing file descriptors</a></li>
34<li><a href="#Watcher_Specific_Functions">Watcher-Specific Functions</a></li>
35</ul>
36</li>
33<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a></li> 37<li><a href="#code_ev_timer_code_relative_and_opti"><code>ev_timer</code> - relative and optionally repeating timeouts</a>
38<ul><li><a href="#Watcher_Specific_Functions_and_Data_">Watcher-Specific Functions and Data Members</a></li>
39</ul>
40</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> 41<li><a href="#code_ev_periodic_code_to_cron_or_not"><code>ev_periodic</code> - to cron or not to cron?</a>
42<ul><li><a href="#Watcher_Specific_Functions_and_Data_-3">Watcher-Specific Functions and Data Members</a></li>
43</ul>
44</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> 45<li><a href="#code_ev_signal_code_signal_me_when_a"><code>ev_signal</code> - signal me when a signal gets signalled!</a>
46<ul><li><a href="#Watcher_Specific_Functions_and_Data_-4">Watcher-Specific Functions and Data Members</a></li>
47</ul>
48</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> 49<li><a href="#code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</a>
50<ul><li><a href="#Watcher_Specific_Functions_and_Data_-5">Watcher-Specific Functions and Data Members</a></li>
51</ul>
52</li>
37<li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</a></li> 53<li><a href="#code_ev_stat_code_did_the_file_attri"><code>ev_stat</code> - did the file attributes just change?</a>
54<ul><li><a href="#Watcher_Specific_Functions_and_Data_-6">Watcher-Specific Functions and Data Members</a></li>
55</ul>
56</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> 57<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>
58<ul><li><a href="#Watcher_Specific_Functions_and_Data_-7">Watcher-Specific Functions and Data Members</a></li>
59</ul>
60</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> 61<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>
62<ul><li><a href="#Watcher_Specific_Functions_and_Data_-8">Watcher-Specific Functions and Data Members</a></li>
63</ul>
64</li>
40<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a></li> 65<li><a href="#code_ev_embed_code_when_one_backend_"><code>ev_embed</code> - when one backend isn't enough...</a>
66<ul><li><a href="#Watcher_Specific_Functions_and_Data_-9">Watcher-Specific Functions and Data Members</a></li>
67</ul>
68</li>
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> 69<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>
42</ul> 70</ul>
43</li> 71</li>
44<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li> 72<li><a href="#OTHER_FUNCTIONS">OTHER FUNCTIONS</a></li>
45<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li> 73<li><a href="#LIBEVENT_EMULATION">LIBEVENT EMULATION</a></li>
… …
185you actually want to know.</p> 213you actually want to know.</p>
186 </dd> 214 </dd>
187 <dt>int ev_version_major ()</dt> 215 <dt>int ev_version_major ()</dt>
188 <dt>int ev_version_minor ()</dt> 216 <dt>int ev_version_minor ()</dt>
189 <dd> 217 <dd>
190 <p>You can find out the major and minor version numbers of the library 218 <p>You can find out the major and minor ABI version numbers of the library
191you linked against by calling the functions <code>ev_version_major</code> and 219you linked against by calling the functions <code>ev_version_major</code> and
192<code>ev_version_minor</code>. If you want, you can compare against the global 220<code>ev_version_minor</code>. If you want, you can compare against the global
193symbols <code>EV_VERSION_MAJOR</code> and <code>EV_VERSION_MINOR</code>, which specify the 221symbols <code>EV_VERSION_MAJOR</code> and <code>EV_VERSION_MINOR</code>, which specify the
194version of the library your program was compiled against.</p> 222version of the library your program was compiled against.</p>
223 <p>These version numbers refer to the ABI version of the library, not the
224release version.</p>
195 <p>Usually, it's a good idea to terminate if the major versions mismatch, 225 <p>Usually, it's a good idea to terminate if the major versions mismatch,
196as this indicates an incompatible change. Minor versions are usually 226as this indicates an incompatible change. Minor versions are usually
197compatible to older versions, so a larger minor version alone is usually 227compatible to older versions, so a larger minor version alone is usually
198not a problem.</p> 228not a problem.</p>
199 <p>Example: Make sure we haven't accidentally been linked against the wrong 229 <p>Example: Make sure we haven't accidentally been linked against the wrong
200version.</p> 230version.</p>
201<pre> assert ((&quot;libev version mismatch&quot;, 231<pre> assert ((&quot;libev version mismatch&quot;,
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529one iteration of the loop. This is useful if you are waiting for some 559one iteration of the loop. This is useful if you are waiting for some
530external event in conjunction with something not expressible using other 560external event in conjunction with something not expressible using other
531libev watchers. However, a pair of <code>ev_prepare</code>/<code>ev_check</code> watchers is 561libev watchers. However, a pair of <code>ev_prepare</code>/<code>ev_check</code> watchers is
532usually a better approach for this kind of thing.</p> 562usually a better approach for this kind of thing.</p>
533 <p>Here are the gory details of what <code>ev_loop</code> does:</p> 563 <p>Here are the gory details of what <code>ev_loop</code> does:</p>
564<pre> - Before the first iteration, call any pending watchers.
534<pre> * If there are no active watchers (reference count is zero), return. 565 * If there are no active watchers (reference count is zero), return.
535 - Queue prepare watchers and then call all outstanding watchers. 566 - Queue all prepare watchers and then call all outstanding watchers.
536 - If we have been forked, recreate the kernel state. 567 - If we have been forked, recreate the kernel state.
537 - Update the kernel state with all outstanding changes. 568 - Update the kernel state with all outstanding changes.
538 - Update the &quot;event loop time&quot;. 569 - Update the &quot;event loop time&quot;.
539 - Calculate for how long to block. 570 - Calculate for how long to block.
540 - Block the process, waiting for any events. 571 - Block the process, waiting for any events.
… …
938<p>If you cannot run the fd in non-blocking mode (for example you should not 969<p>If you cannot run the fd in non-blocking mode (for example you should not
939play around with an Xlib connection), then you have to seperately re-test 970play around with an Xlib connection), then you have to seperately re-test
940whether a file descriptor is really ready with a known-to-be good interface 971whether a file descriptor is really ready with a known-to-be good interface
941such as poll (fortunately in our Xlib example, Xlib already does this on 972such as poll (fortunately in our Xlib example, Xlib already does this on
942its own, so its quite safe to use).</p> 973its own, so its quite safe to use).</p>
974
975</div>
976<h3 id="The_special_problem_of_disappearing_">The special problem of disappearing file descriptors</h3>
977<div id="The_special_problem_of_disappearing_-2">
978<p>Some backends (e.g kqueue, epoll) need to be told about closing a file
979descriptor (either by calling <code>close</code> explicitly or by any other means,
980such as <code>dup</code>). The reason is that you register interest in some file
981descriptor, but when it goes away, the operating system will silently drop
982this interest. If another file descriptor with the same number then is
983registered with libev, there is no efficient way to see that this is, in
984fact, a different file descriptor.</p>
985<p>To avoid having to explicitly tell libev about such cases, libev follows
986the following policy: Each time <code>ev_io_set</code> is being called, libev
987will assume that this is potentially a new file descriptor, otherwise
988it is assumed that the file descriptor stays the same. That means that
989you <i>have</i> to call <code>ev_io_set</code> (or <code>ev_io_init</code>) when you change the
990descriptor even if the file descriptor number itself did not change.</p>
991<p>This is how one would do it normally anyway, the important point is that
992the libev application should not optimise around libev but should leave
993optimisations to libev.</p>
994
995
996
997
998
999</div>
1000<h3 id="Watcher_Specific_Functions">Watcher-Specific Functions</h3>
1001<div id="Watcher_Specific_Functions_CONTENT">
943<dl> 1002<dl>
944 <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt> 1003 <dt>ev_io_init (ev_io *, callback, int fd, int events)</dt>
945 <dt>ev_io_set (ev_io *, int fd, int events)</dt> 1004 <dt>ev_io_set (ev_io *, int fd, int events)</dt>
946 <dd> 1005 <dd>
947 <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to 1006 <p>Configures an <code>ev_io</code> watcher. The <code>fd</code> is the file descriptor to
… …
998 1057
999</pre> 1058</pre>
1000<p>The callback is guarenteed to be invoked only when its timeout has passed, 1059<p>The callback is guarenteed to be invoked only when its timeout has passed,
1001but if multiple timers become ready during the same loop iteration then 1060but if multiple timers become ready during the same loop iteration then
1002order of execution is undefined.</p> 1061order of execution is undefined.</p>
1062
1063</div>
1064<h3 id="Watcher_Specific_Functions_and_Data_">Watcher-Specific Functions and Data Members</h3>
1065<div id="Watcher_Specific_Functions_and_Data_-2">
1003<dl> 1066<dl>
1004 <dt>ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)</dt> 1067 <dt>ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)</dt>
1005 <dt>ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)</dt> 1068 <dt>ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)</dt>
1006 <dd> 1069 <dd>
1007 <p>Configure the timer to trigger after <code>after</code> seconds. If <code>repeat</code> is 1070 <p>Configure the timer to trigger after <code>after</code> seconds. If <code>repeat</code> is
… …
1096but on wallclock time (absolute time). You can tell a periodic watcher 1159but on wallclock time (absolute time). You can tell a periodic watcher
1097to trigger &quot;at&quot; some specific point in time. For example, if you tell a 1160to trigger &quot;at&quot; some specific point in time. For example, if you tell a
1098periodic watcher to trigger in 10 seconds (by specifiying e.g. <code>ev_now () 1161periodic watcher to trigger in 10 seconds (by specifiying e.g. <code>ev_now ()
1099+ 10.</code>) and then reset your system clock to the last year, then it will 1162+ 10.</code>) and then reset your system clock to the last year, then it will
1100take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger 1163take a year to trigger the event (unlike an <code>ev_timer</code>, which would trigger
1101roughly 10 seconds later and of course not if you reset your system time 1164roughly 10 seconds later).</p>
1102again).</p>
1103<p>They can also be used to implement vastly more complex timers, such as 1165<p>They can also be used to implement vastly more complex timers, such as
1104triggering an event on eahc midnight, local time.</p> 1166triggering an event on each midnight, local time or other, complicated,
1167rules.</p>
1105<p>As with timers, the callback is guarenteed to be invoked only when the 1168<p>As with timers, the callback is guarenteed to be invoked only when the
1106time (<code>at</code>) has been passed, but if multiple periodic timers become ready 1169time (<code>at</code>) has been passed, but if multiple periodic timers become ready
1107during the same loop iteration then order of execution is undefined.</p> 1170during the same loop iteration then order of execution is undefined.</p>
1171
1172</div>
1173<h3 id="Watcher_Specific_Functions_and_Data_-3">Watcher-Specific Functions and Data Members</h3>
1174<div id="Watcher_Specific_Functions_and_Data_-2">
1108<dl> 1175<dl>
1109 <dt>ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)</dt> 1176 <dt>ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)</dt>
1110 <dt>ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)</dt> 1177 <dt>ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb)</dt>
1111 <dd> 1178 <dd>
1112 <p>Lots of arguments, lets sort it out... There are basically three modes of 1179 <p>Lots of arguments, lets sort it out... There are basically three modes of
1113operation, and we will explain them from simplest to complex:</p> 1180operation, and we will explain them from simplest to complex:</p>
1114 <p> 1181 <p>
1115 <dl> 1182 <dl>
1116 <dt>* absolute timer (interval = reschedule_cb = 0)</dt> 1183 <dt>* absolute timer (at = time, interval = reschedule_cb = 0)</dt>
1117 <dd> 1184 <dd>
1118 <p>In this configuration the watcher triggers an event at the wallclock time 1185 <p>In this configuration the watcher triggers an event at the wallclock time
1119<code>at</code> and doesn't repeat. It will not adjust when a time jump occurs, 1186<code>at</code> and doesn't repeat. It will not adjust when a time jump occurs,
1120that is, if it is to be run at January 1st 2011 then it will run when the 1187that is, if it is to be run at January 1st 2011 then it will run when the
1121system time reaches or surpasses this time.</p> 1188system time reaches or surpasses this time.</p>
1122 </dd> 1189 </dd>
1123 <dt>* non-repeating interval timer (interval &gt; 0, reschedule_cb = 0)</dt> 1190 <dt>* non-repeating interval timer (at = offset, interval &gt; 0, reschedule_cb = 0)</dt>
1124 <dd> 1191 <dd>
1125 <p>In this mode the watcher will always be scheduled to time out at the next 1192 <p>In this mode the watcher will always be scheduled to time out at the next
1126<code>at + N * interval</code> time (for some integer N) and then repeat, regardless 1193<code>at + N * interval</code> time (for some integer N, which can also be negative)
1127of any time jumps.</p> 1194and then repeat, regardless of any time jumps.</p>
1128 <p>This can be used to create timers that do not drift with respect to system 1195 <p>This can be used to create timers that do not drift with respect to system
1129time:</p> 1196time:</p>
1130<pre> ev_periodic_set (&amp;periodic, 0., 3600., 0); 1197<pre> ev_periodic_set (&amp;periodic, 0., 3600., 0);
1131 1198
1132</pre> 1199</pre>
… …
1135full hour (UTC), or more correctly, when the system time is evenly divisible 1202full hour (UTC), or more correctly, when the system time is evenly divisible
1136by 3600.</p> 1203by 3600.</p>
1137 <p>Another way to think about it (for the mathematically inclined) is that 1204 <p>Another way to think about it (for the mathematically inclined) is that
1138<code>ev_periodic</code> will try to run the callback in this mode at the next possible 1205<code>ev_periodic</code> will try to run the callback in this mode at the next possible
1139time where <code>time = at (mod interval)</code>, regardless of any time jumps.</p> 1206time where <code>time = at (mod interval)</code>, regardless of any time jumps.</p>
1207 <p>For numerical stability it is preferable that the <code>at</code> value is near
1208<code>ev_now ()</code> (the current time), but there is no range requirement for
1209this value.</p>
1140 </dd> 1210 </dd>
1141 <dt>* manual reschedule mode (reschedule_cb = callback)</dt> 1211 <dt>* manual reschedule mode (at and interval ignored, reschedule_cb = callback)</dt>
1142 <dd> 1212 <dd>
1143 <p>In this mode the values for <code>interval</code> and <code>at</code> are both being 1213 <p>In this mode the values for <code>interval</code> and <code>at</code> are both being
1144ignored. Instead, each time the periodic watcher gets scheduled, the 1214ignored. Instead, each time the periodic watcher gets scheduled, the
1145reschedule callback will be called with the watcher as first, and the 1215reschedule callback will be called with the watcher as first, and the
1146current time as second argument.</p> 1216current time as second argument.</p>
1147 <p>NOTE: <i>This callback MUST NOT stop or destroy any periodic watcher, 1217 <p>NOTE: <i>This callback MUST NOT stop or destroy any periodic watcher,
1148ever, or make any event loop modifications</i>. If you need to stop it, 1218ever, or make any event loop modifications</i>. If you need to stop it,
1149return <code>now + 1e30</code> (or so, fudge fudge) and stop it afterwards (e.g. by 1219return <code>now + 1e30</code> (or so, fudge fudge) and stop it afterwards (e.g. by
1150starting a prepare watcher).</p> 1220starting an <code>ev_prepare</code> watcher, which is legal).</p>
1151 <p>Its prototype is <code>ev_tstamp (*reschedule_cb)(struct ev_periodic *w, 1221 <p>Its prototype is <code>ev_tstamp (*reschedule_cb)(struct ev_periodic *w,
1152ev_tstamp now)</code>, e.g.:</p> 1222ev_tstamp now)</code>, e.g.:</p>
1153<pre> static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) 1223<pre> static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now)
1154 { 1224 {
1155 return now + 60.; 1225 return now + 60.;
… …
1175 <dd> 1245 <dd>
1176 <p>Simply stops and restarts the periodic watcher again. This is only useful 1246 <p>Simply stops and restarts the periodic watcher again. This is only useful
1177when you changed some parameters or the reschedule callback would return 1247when you changed some parameters or the reschedule callback would return
1178a different time than the last time it was called (e.g. in a crond like 1248a different time than the last time it was called (e.g. in a crond like
1179program when the crontabs have changed).</p> 1249program when the crontabs have changed).</p>
1250 </dd>
1251 <dt>ev_tstamp offset [read-write]</dt>
1252 <dd>
1253 <p>When repeating, this contains the offset value, otherwise this is the
1254absolute point in time (the <code>at</code> value passed to <code>ev_periodic_set</code>).</p>
1255 <p>Can be modified any time, but changes only take effect when the periodic
1256timer fires or <code>ev_periodic_again</code> is being called.</p>
1180 </dd> 1257 </dd>
1181 <dt>ev_tstamp interval [read-write]</dt> 1258 <dt>ev_tstamp interval [read-write]</dt>
1182 <dd> 1259 <dd>
1183 <p>The current interval value. Can be modified any time, but changes only 1260 <p>The current interval value. Can be modified any time, but changes only
1184take effect when the periodic timer fires or <code>ev_periodic_again</code> is being 1261take effect when the periodic timer fires or <code>ev_periodic_again</code> is being
… …
1239first watcher gets started will libev actually register a signal watcher 1316first watcher gets started will libev actually register a signal watcher
1240with the kernel (thus it coexists with your own signal handlers as long 1317with the kernel (thus it coexists with your own signal handlers as long
1241as you don't register any with libev). Similarly, when the last signal 1318as you don't register any with libev). Similarly, when the last signal
1242watcher for a signal is stopped libev will reset the signal handler to 1319watcher for a signal is stopped libev will reset the signal handler to
1243SIG_DFL (regardless of what it was set to before).</p> 1320SIG_DFL (regardless of what it was set to before).</p>
1321
1322</div>
1323<h3 id="Watcher_Specific_Functions_and_Data_-4">Watcher-Specific Functions and Data Members</h3>
1324<div id="Watcher_Specific_Functions_and_Data_-2-2">
1244<dl> 1325<dl>
1245 <dt>ev_signal_init (ev_signal *, callback, int signum)</dt> 1326 <dt>ev_signal_init (ev_signal *, callback, int signum)</dt>
1246 <dt>ev_signal_set (ev_signal *, int signum)</dt> 1327 <dt>ev_signal_set (ev_signal *, int signum)</dt>
1247 <dd> 1328 <dd>
1248 <p>Configures the watcher to trigger on the given signal number (usually one 1329 <p>Configures the watcher to trigger on the given signal number (usually one
… …
1261</div> 1342</div>
1262<h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2> 1343<h2 id="code_ev_child_code_watch_out_for_pro"><code>ev_child</code> - watch out for process status changes</h2>
1263<div id="code_ev_child_code_watch_out_for_pro-2"> 1344<div id="code_ev_child_code_watch_out_for_pro-2">
1264<p>Child watchers trigger when your process receives a SIGCHLD in response to 1345<p>Child watchers trigger when your process receives a SIGCHLD in response to
1265some child status changes (most typically when a child of yours dies).</p> 1346some child status changes (most typically when a child of yours dies).</p>
1347
1348</div>
1349<h3 id="Watcher_Specific_Functions_and_Data_-5">Watcher-Specific Functions and Data Members</h3>
1350<div id="Watcher_Specific_Functions_and_Data_-2-3">
1266<dl> 1351<dl>
1267 <dt>ev_child_init (ev_child *, callback, int pid)</dt> 1352 <dt>ev_child_init (ev_child *, callback, int pid)</dt>
1268 <dt>ev_child_set (ev_child *, int pid)</dt> 1353 <dt>ev_child_set (ev_child *, int pid)</dt>
1269 <dd> 1354 <dd>
1270 <p>Configures the watcher to wait for status changes of process <code>pid</code> (or 1355 <p>Configures the watcher to wait for status changes of process <code>pid</code> (or
… …
1333reader). Inotify will be used to give hints only and should not change the 1418reader). Inotify will be used to give hints only and should not change the
1334semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs 1419semantics of <code>ev_stat</code> watchers, which means that libev sometimes needs
1335to fall back to regular polling again even with inotify, but changes are 1420to fall back to regular polling again even with inotify, but changes are
1336usually detected immediately, and if the file exists there will be no 1421usually detected immediately, and if the file exists there will be no
1337polling.</p> 1422polling.</p>
1423
1424</div>
1425<h3 id="Watcher_Specific_Functions_and_Data_-6">Watcher-Specific Functions and Data Members</h3>
1426<div id="Watcher_Specific_Functions_and_Data_-2-4">
1338<dl> 1427<dl>
1339 <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt> 1428 <dt>ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)</dt>
1340 <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt> 1429 <dt>ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)</dt>
1341 <dd> 1430 <dd>
1342 <p>Configures the watcher to wait for status changes of the given 1431 <p>Configures the watcher to wait for status changes of the given
… …
1420active, the process will not block when waiting for new events.</p> 1509active, the process will not block when waiting for new events.</p>
1421<p>Apart from keeping your process non-blocking (which is a useful 1510<p>Apart from keeping your process non-blocking (which is a useful
1422effect on its own sometimes), idle watchers are a good place to do 1511effect on its own sometimes), idle watchers are a good place to do
1423&quot;pseudo-background processing&quot;, or delay processing stuff to after the 1512&quot;pseudo-background processing&quot;, or delay processing stuff to after the
1424event loop has handled all outstanding events.</p> 1513event loop has handled all outstanding events.</p>
1514
1515</div>
1516<h3 id="Watcher_Specific_Functions_and_Data_-7">Watcher-Specific Functions and Data Members</h3>
1517<div id="Watcher_Specific_Functions_and_Data_-2-5">
1425<dl> 1518<dl>
1426 <dt>ev_idle_init (ev_signal *, callback)</dt> 1519 <dt>ev_idle_init (ev_signal *, callback)</dt>
1427 <dd> 1520 <dd>
1428 <p>Initialises and configures the idle watcher - it has no parameters of any 1521 <p>Initialises and configures the idle watcher - it has no parameters of any
1429kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless, 1522kind. There is a <code>ev_idle_set</code> macro, but using it is utterly pointless,
… …
1483are ready to run (it's actually more complicated: it only runs coroutines 1576are ready to run (it's actually more complicated: it only runs coroutines
1484with priority higher than or equal to the event loop and one coroutine 1577with priority higher than or equal to the event loop and one coroutine
1485of lower priority, but only once, using idle watchers to keep the event 1578of lower priority, but only once, using idle watchers to keep the event
1486loop from blocking if lower-priority coroutines are active, thus mapping 1579loop from blocking if lower-priority coroutines are active, thus mapping
1487low-priority coroutines to idle/background tasks).</p> 1580low-priority coroutines to idle/background tasks).</p>
1581<p>It is recommended to give <code>ev_check</code> watchers highest (<code>EV_MAXPRI</code>)
1582priority, to ensure that they are being run before any other watchers
1583after the poll. Also, <code>ev_check</code> watchers (and <code>ev_prepare</code> watchers,
1584too) should not activate (&quot;feed&quot;) events into libev. While libev fully
1585supports this, they will be called before other <code>ev_check</code> watchers did
1586their job. As <code>ev_check</code> watchers are often used to embed other event
1587loops those other event loops might be in an unusable state until their
1588<code>ev_check</code> watcher ran (always remind yourself to coexist peacefully with
1589others).</p>
1590
1591</div>
1592<h3 id="Watcher_Specific_Functions_and_Data_-8">Watcher-Specific Functions and Data Members</h3>
1593<div id="Watcher_Specific_Functions_and_Data_-2-6">
1488<dl> 1594<dl>
1489 <dt>ev_prepare_init (ev_prepare *, callback)</dt> 1595 <dt>ev_prepare_init (ev_prepare *, callback)</dt>
1490 <dt>ev_check_init (ev_check *, callback)</dt> 1596 <dt>ev_check_init (ev_check *, callback)</dt>
1491 <dd> 1597 <dd>
1492 <p>Initialises and configures the prepare or check watcher - they have no 1598 <p>Initialises and configures the prepare or check watcher - they have no
… …
1684 } 1790 }
1685 else 1791 else
1686 loop_lo = loop_hi; 1792 loop_lo = loop_hi;
1687 1793
1688</pre> 1794</pre>
1795
1796</div>
1797<h3 id="Watcher_Specific_Functions_and_Data_-9">Watcher-Specific Functions and Data Members</h3>
1798<div id="Watcher_Specific_Functions_and_Data_-2-7">
1689<dl> 1799<dl>
1690 <dt>ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)</dt> 1800 <dt>ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)</dt>
1691 <dt>ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)</dt> 1801 <dt>ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop)</dt>
1692 <dd> 1802 <dd>
1693 <p>Configures the watcher to embed the given loop, which must be 1803 <p>Configures the watcher to embed the given loop, which must be

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