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Revision 1.25 by root, Tue Nov 27 19:23:31 2007 UTC vs.
Revision 1.31 by root, Wed Nov 28 11:31:34 2007 UTC

… …
127.\} 127.\}
128.rm #[ #] #H #V #F C 128.rm #[ #] #H #V #F C
129.\" ======================================================================== 129.\" ========================================================================
130.\" 130.\"
131.IX Title ""<STANDARD INPUT>" 1" 131.IX Title ""<STANDARD INPUT>" 1"
132.TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-11-28" "perl v5.8.8" "User Contributed Perl Documentation"
133.SH "NAME" 133.SH "NAME"
134libev \- a high performance full\-featured event loop written in C 134libev \- a high performance full\-featured event loop written in C
135.SH "SYNOPSIS" 135.SH "SYNOPSIS"
136.IX Header "SYNOPSIS" 136.IX Header "SYNOPSIS"
137.Vb 1 137.Vb 1
138\& #include <ev.h> 138\& #include <ev.h>
139.Ve 139.Ve
140.SH "EXAMPLE PROGRAM"
141.IX Header "EXAMPLE PROGRAM"
142.Vb 1
143\& #include <ev.h>
144.Ve
145.PP
146.Vb 2
147\& ev_io stdin_watcher;
148\& ev_timer timeout_watcher;
149.Ve
150.PP
151.Vb 8
152\& /* called when data readable on stdin */
153\& static void
154\& stdin_cb (EV_P_ struct ev_io *w, int revents)
155\& {
156\& /* puts ("stdin ready"); */
157\& ev_io_stop (EV_A_ w); /* just a syntax example */
158\& ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */
159\& }
160.Ve
161.PP
162.Vb 6
163\& static void
164\& timeout_cb (EV_P_ struct ev_timer *w, int revents)
165\& {
166\& /* puts ("timeout"); */
167\& ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
168\& }
169.Ve
170.PP
171.Vb 4
172\& int
173\& main (void)
174\& {
175\& struct ev_loop *loop = ev_default_loop (0);
176.Ve
177.PP
178.Vb 3
179\& /* initialise an io watcher, then start it */
180\& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
181\& ev_io_start (loop, &stdin_watcher);
182.Ve
183.PP
184.Vb 3
185\& /* simple non-repeating 5.5 second timeout */
186\& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
187\& ev_timer_start (loop, &timeout_watcher);
188.Ve
189.PP
190.Vb 2
191\& /* loop till timeout or data ready */
192\& ev_loop (loop, 0);
193.Ve
194.PP
195.Vb 2
196\& return 0;
197\& }
198.Ve
140.SH "DESCRIPTION" 199.SH "DESCRIPTION"
141.IX Header "DESCRIPTION" 200.IX Header "DESCRIPTION"
142Libev is an event loop: you register interest in certain events (such as a 201Libev is an event loop: you register interest in certain events (such as a
143file descriptor being readable or a timeout occuring), and it will manage 202file descriptor being readable or a timeout occuring), and it will manage
144these event sources and provide your program with events. 203these event sources and provide your program with events.
… …
151watchers\fR, which are relatively small C structures you initialise with the 210watchers\fR, which are relatively small C structures you initialise with the
152details of the event, and then hand it over to libev by \fIstarting\fR the 211details of the event, and then hand it over to libev by \fIstarting\fR the
153watcher. 212watcher.
154.SH "FEATURES" 213.SH "FEATURES"
155.IX Header "FEATURES" 214.IX Header "FEATURES"
156Libev supports select, poll, the linux-specific epoll and the bsd-specific 215Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the
157kqueue mechanisms for file descriptor events, relative timers, absolute 216BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms
158timers with customised rescheduling, signal events, process status change 217for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface
159events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event 218(for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers
160loop mechanism itself (idle, prepare and check watchers). It also is quite 219with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals
161fast (see this benchmark comparing 220(\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and event
162it to libevent for example). 221watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR,
222\&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as
223file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events
224(\f(CW\*(C`ev_fork\*(C'\fR).
225.PP
226It also is quite fast (see this
227benchmark comparing it to libevent
228for example).
163.SH "CONVENTIONS" 229.SH "CONVENTIONS"
164.IX Header "CONVENTIONS" 230.IX Header "CONVENTIONS"
165Libev is very configurable. In this manual the default configuration 231Libev is very configurable. In this manual the default configuration will
166will be described, which supports multiple event loops. For more info 232be described, which supports multiple event loops. For more info about
167about various configuration options please have a look at the file 233various configuration options please have a look at \fB\s-1EMBED\s0\fR section in
168\&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without 234this manual. If libev was configured without support for multiple event
169support for multiple event loops, then all functions taking an initial 235loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR
170argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) 236(which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument.
171will not have this argument.
172.SH "TIME REPRESENTATION" 237.SH "TIME REPRESENTATION"
173.IX Header "TIME REPRESENTATION" 238.IX Header "TIME REPRESENTATION"
174Libev represents time as a single floating point number, representing the 239Libev represents time as a single floating point number, representing the
175(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near 240(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near
176the beginning of 1970, details are complicated, don't ask). This type is 241the beginning of 1970, details are complicated, don't ask). This type is
… …
201Usually, it's a good idea to terminate if the major versions mismatch, 266Usually, it's a good idea to terminate if the major versions mismatch,
202as this indicates an incompatible change. Minor versions are usually 267as this indicates an incompatible change. Minor versions are usually
203compatible to older versions, so a larger minor version alone is usually 268compatible to older versions, so a larger minor version alone is usually
204not a problem. 269not a problem.
205.Sp 270.Sp
206Example: make sure we haven't accidentally been linked against the wrong 271Example: Make sure we haven't accidentally been linked against the wrong
207version: 272version.
208.Sp 273.Sp
209.Vb 3 274.Vb 3
210\& assert (("libev version mismatch", 275\& assert (("libev version mismatch",
211\& ev_version_major () == EV_VERSION_MAJOR 276\& ev_version_major () == EV_VERSION_MAJOR
212\& && ev_version_minor () >= EV_VERSION_MINOR)); 277\& && ev_version_minor () >= EV_VERSION_MINOR));
… …
240might be supported on the current system, you would need to look at 305might be supported on the current system, you would need to look at
241\&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for 306\&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for
242recommended ones. 307recommended ones.
243.Sp 308.Sp
244See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. 309See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
245.IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 310.IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4
246.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" 311.IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))"
247Sets the allocation function to use (the prototype is similar to the 312Sets the allocation function to use (the prototype and semantics are
248realloc C function, the semantics are identical). It is used to allocate 313identical to the realloc C function). It is used to allocate and free
249and free memory (no surprises here). If it returns zero when memory 314memory (no surprises here). If it returns zero when memory needs to be
250needs to be allocated, the library might abort or take some potentially 315allocated, the library might abort or take some potentially destructive
251destructive action. The default is your system realloc function. 316action. The default is your system realloc function.
252.Sp 317.Sp
253You could override this function in high-availability programs to, say, 318You could override this function in high-availability programs to, say,
254free some memory if it cannot allocate memory, to use a special allocator, 319free some memory if it cannot allocate memory, to use a special allocator,
255or even to sleep a while and retry until some memory is available. 320or even to sleep a while and retry until some memory is available.
256.Sp 321.Sp
257Example: replace the libev allocator with one that waits a bit and then 322Example: Replace the libev allocator with one that waits a bit and then
258retries: better than mine). 323retries).
259.Sp 324.Sp
260.Vb 6 325.Vb 6
261\& static void * 326\& static void *
262\& persistent_realloc (void *ptr, long size) 327\& persistent_realloc (void *ptr, size_t size)
263\& { 328\& {
264\& for (;;) 329\& for (;;)
265\& { 330\& {
266\& void *newptr = realloc (ptr, size); 331\& void *newptr = realloc (ptr, size);
267.Ve 332.Ve
… …
289callback is set, then libev will expect it to remedy the sitution, no 354callback is set, then libev will expect it to remedy the sitution, no
290matter what, when it returns. That is, libev will generally retry the 355matter what, when it returns. That is, libev will generally retry the
291requested operation, or, if the condition doesn't go away, do bad stuff 356requested operation, or, if the condition doesn't go away, do bad stuff
292(such as abort). 357(such as abort).
293.Sp 358.Sp
294Example: do the same thing as libev does internally: 359Example: This is basically the same thing that libev does internally, too.
295.Sp 360.Sp
296.Vb 6 361.Vb 6
297\& static void 362\& static void
298\& fatal_error (const char *msg) 363\& fatal_error (const char *msg)
299\& { 364\& {
… …
448Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is 513Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is
449always distinct from the default loop. Unlike the default loop, it cannot 514always distinct from the default loop. Unlike the default loop, it cannot
450handle signal and child watchers, and attempts to do so will be greeted by 515handle signal and child watchers, and attempts to do so will be greeted by
451undefined behaviour (or a failed assertion if assertions are enabled). 516undefined behaviour (or a failed assertion if assertions are enabled).
452.Sp 517.Sp
453Example: try to create a event loop that uses epoll and nothing else. 518Example: Try to create a event loop that uses epoll and nothing else.
454.Sp 519.Sp
455.Vb 3 520.Vb 3
456\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); 521\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
457\& if (!epoller) 522\& if (!epoller)
458\& fatal ("no epoll found here, maybe it hides under your chair"); 523\& fatal ("no epoll found here, maybe it hides under your chair");
… …
556\& be handled here by queueing them when their watcher gets executed. 621\& be handled here by queueing them when their watcher gets executed.
557\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK 622\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
558\& were used, return, otherwise continue with step *. 623\& were used, return, otherwise continue with step *.
559.Ve 624.Ve
560.Sp 625.Sp
561Example: queue some jobs and then loop until no events are outsanding 626Example: Queue some jobs and then loop until no events are outsanding
562anymore. 627anymore.
563.Sp 628.Sp
564.Vb 4 629.Vb 4
565\& ... queue jobs here, make sure they register event watchers as long 630\& ... queue jobs here, make sure they register event watchers as long
566\& ... as they still have work to do (even an idle watcher will do..) 631\& ... as they still have work to do (even an idle watcher will do..)
… …
588visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if 653visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if
589no event watchers registered by it are active. It is also an excellent 654no event watchers registered by it are active. It is also an excellent
590way to do this for generic recurring timers or from within third-party 655way to do this for generic recurring timers or from within third-party
591libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR. 656libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
592.Sp 657.Sp
593Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR 658Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR
594running when nothing else is active. 659running when nothing else is active.
595.Sp 660.Sp
596.Vb 4 661.Vb 4
597\& struct dv_signal exitsig; 662\& struct ev_signal exitsig;
598\& ev_signal_init (&exitsig, sig_cb, SIGINT); 663\& ev_signal_init (&exitsig, sig_cb, SIGINT);
599\& ev_signal_start (myloop, &exitsig); 664\& ev_signal_start (loop, &exitsig);
600\& evf_unref (myloop); 665\& evf_unref (loop);
601.Ve 666.Ve
602.Sp 667.Sp
603Example: for some weird reason, unregister the above signal handler again. 668Example: For some weird reason, unregister the above signal handler again.
604.Sp 669.Sp
605.Vb 2 670.Vb 2
606\& ev_ref (myloop); 671\& ev_ref (loop);
607\& ev_signal_stop (myloop, &exitsig); 672\& ev_signal_stop (loop, &exitsig);
608.Ve 673.Ve
609.SH "ANATOMY OF A WATCHER" 674.SH "ANATOMY OF A WATCHER"
610.IX Header "ANATOMY OF A WATCHER" 675.IX Header "ANATOMY OF A WATCHER"
611A watcher is a structure that you create and register to record your 676A watcher is a structure that you create and register to record your
612interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to 677interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to
… …
792Returns a true value iff the watcher is pending, (i.e. it has outstanding 857Returns a true value iff the watcher is pending, (i.e. it has outstanding
793events but its callback has not yet been invoked). As long as a watcher 858events but its callback has not yet been invoked). As long as a watcher
794is pending (but not active) you must not call an init function on it (but 859is pending (but not active) you must not call an init function on it (but
795\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to 860\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to
796libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). 861libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it).
797.IP "callback = ev_cb (ev_TYPE *watcher)" 4 862.IP "callback ev_cb (ev_TYPE *watcher)" 4
798.IX Item "callback = ev_cb (ev_TYPE *watcher)" 863.IX Item "callback ev_cb (ev_TYPE *watcher)"
799Returns the callback currently set on the watcher. 864Returns the callback currently set on the watcher.
800.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 865.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
801.IX Item "ev_cb_set (ev_TYPE *watcher, callback)" 866.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
802Change the callback. You can change the callback at virtually any time 867Change the callback. You can change the callback at virtually any time
803(modulo threads). 868(modulo threads).
… …
829\& struct my_io *w = (struct my_io *)w_; 894\& struct my_io *w = (struct my_io *)w_;
830\& ... 895\& ...
831\& } 896\& }
832.Ve 897.Ve
833.PP 898.PP
834More interesting and less C\-conformant ways of catsing your callback type 899More interesting and less C\-conformant ways of casting your callback type
835have been omitted.... 900instead have been omitted.
901.PP
902Another common scenario is having some data structure with multiple
903watchers:
904.PP
905.Vb 6
906\& struct my_biggy
907\& {
908\& int some_data;
909\& ev_timer t1;
910\& ev_timer t2;
911\& }
912.Ve
913.PP
914In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated,
915you need to use \f(CW\*(C`offsetof\*(C'\fR:
916.PP
917.Vb 1
918\& #include <stddef.h>
919.Ve
920.PP
921.Vb 6
922\& static void
923\& t1_cb (EV_P_ struct ev_timer *w, int revents)
924\& {
925\& struct my_biggy big = (struct my_biggy *
926\& (((char *)w) - offsetof (struct my_biggy, t1));
927\& }
928.Ve
929.PP
930.Vb 6
931\& static void
932\& t2_cb (EV_P_ struct ev_timer *w, int revents)
933\& {
934\& struct my_biggy big = (struct my_biggy *
935\& (((char *)w) - offsetof (struct my_biggy, t2));
936\& }
937.Ve
836.SH "WATCHER TYPES" 938.SH "WATCHER TYPES"
837.IX Header "WATCHER TYPES" 939.IX Header "WATCHER TYPES"
838This section describes each watcher in detail, but will not repeat 940This section describes each watcher in detail, but will not repeat
839information given in the last section. Any initialisation/set macros, 941information given in the last section. Any initialisation/set macros,
840functions and members specific to the watcher type are explained. 942functions and members specific to the watcher type are explained.
… …
901The file descriptor being watched. 1003The file descriptor being watched.
902.IP "int events [read\-only]" 4 1004.IP "int events [read\-only]" 4
903.IX Item "int events [read-only]" 1005.IX Item "int events [read-only]"
904The events being watched. 1006The events being watched.
905.PP 1007.PP
906Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well 1008Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
907readable, but only once. Since it is likely line\-buffered, you could 1009readable, but only once. Since it is likely line\-buffered, you could
908attempt to read a whole line in the callback: 1010attempt to read a whole line in the callback.
909.PP 1011.PP
910.Vb 6 1012.Vb 6
911\& static void 1013\& static void
912\& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) 1014\& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
913\& { 1015\& {
… …
1005.IX Item "ev_tstamp repeat [read-write]" 1107.IX Item "ev_tstamp repeat [read-write]"
1006The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out 1108The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out
1007or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), 1109or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any),
1008which is also when any modifications are taken into account. 1110which is also when any modifications are taken into account.
1009.PP 1111.PP
1010Example: create a timer that fires after 60 seconds. 1112Example: Create a timer that fires after 60 seconds.
1011.PP 1113.PP
1012.Vb 5 1114.Vb 5
1013\& static void 1115\& static void
1014\& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1116\& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
1015\& { 1117\& {
… …
1021\& struct ev_timer mytimer; 1123\& struct ev_timer mytimer;
1022\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); 1124\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1023\& ev_timer_start (loop, &mytimer); 1125\& ev_timer_start (loop, &mytimer);
1024.Ve 1126.Ve
1025.PP 1127.PP
1026Example: create a timeout timer that times out after 10 seconds of 1128Example: Create a timeout timer that times out after 10 seconds of
1027inactivity. 1129inactivity.
1028.PP 1130.PP
1029.Vb 5 1131.Vb 5
1030\& static void 1132\& static void
1031\& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1133\& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
… …
1156.IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" 1258.IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]"
1157The current reschedule callback, or \f(CW0\fR, if this functionality is 1259The current reschedule callback, or \f(CW0\fR, if this functionality is
1158switched off. Can be changed any time, but changes only take effect when 1260switched off. Can be changed any time, but changes only take effect when
1159the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. 1261the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
1160.PP 1262.PP
1161Example: call a callback every hour, or, more precisely, whenever the 1263Example: Call a callback every hour, or, more precisely, whenever the
1162system clock is divisible by 3600. The callback invocation times have 1264system clock is divisible by 3600. The callback invocation times have
1163potentially a lot of jittering, but good long-term stability. 1265potentially a lot of jittering, but good long-term stability.
1164.PP 1266.PP
1165.Vb 5 1267.Vb 5
1166\& static void 1268\& static void
… …
1174\& struct ev_periodic hourly_tick; 1276\& struct ev_periodic hourly_tick;
1175\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); 1277\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1176\& ev_periodic_start (loop, &hourly_tick); 1278\& ev_periodic_start (loop, &hourly_tick);
1177.Ve 1279.Ve
1178.PP 1280.PP
1179Example: the same as above, but use a reschedule callback to do it: 1281Example: The same as above, but use a reschedule callback to do it:
1180.PP 1282.PP
1181.Vb 1 1283.Vb 1
1182\& #include <math.h> 1284\& #include <math.h>
1183.Ve 1285.Ve
1184.PP 1286.PP
… …
1192.PP 1294.PP
1193.Vb 1 1295.Vb 1
1194\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); 1296\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1195.Ve 1297.Ve
1196.PP 1298.PP
1197Example: call a callback every hour, starting now: 1299Example: Call a callback every hour, starting now:
1198.PP 1300.PP
1199.Vb 4 1301.Vb 4
1200\& struct ev_periodic hourly_tick; 1302\& struct ev_periodic hourly_tick;
1201\& ev_periodic_init (&hourly_tick, clock_cb, 1303\& ev_periodic_init (&hourly_tick, clock_cb,
1202\& fmod (ev_now (loop), 3600.), 3600., 0); 1304\& fmod (ev_now (loop), 3600.), 3600., 0);
… …
1253.IP "int rstatus [read\-write]" 4 1355.IP "int rstatus [read\-write]" 4
1254.IX Item "int rstatus [read-write]" 1356.IX Item "int rstatus [read-write]"
1255The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems 1357The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems
1256\&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). 1358\&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details).
1257.PP 1359.PP
1258Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. 1360Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1259.PP 1361.PP
1260.Vb 5 1362.Vb 5
1261\& static void 1363\& static void
1262\& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) 1364\& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
1263\& { 1365\& {
… …
1282not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is 1384not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is
1283otherwise always forced to be at least one) and all the other fields of 1385otherwise always forced to be at least one) and all the other fields of
1284the stat buffer having unspecified contents. 1386the stat buffer having unspecified contents.
1285.PP 1387.PP
1286Since there is no standard to do this, the portable implementation simply 1388Since there is no standard to do this, the portable implementation simply
1287calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You 1389calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You
1288can specify a recommended polling interval for this case. If you specify 1390can specify a recommended polling interval for this case. If you specify
1289a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, 1391a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
1290unspecified default\fR value will be used (which you can expect to be around 1392unspecified default\fR value will be used (which you can expect to be around
1291five seconds, although this might change dynamically). Libev will also 1393five seconds, although this might change dynamically). Libev will also
1292impose a minimum interval which is currently around \f(CW0.1\fR, but thats 1394impose a minimum interval which is currently around \f(CW0.1\fR, but thats
… …
1294.PP 1396.PP
1295This watcher type is not meant for massive numbers of stat watchers, 1397This watcher type is not meant for massive numbers of stat watchers,
1296as even with OS-supported change notifications, this can be 1398as even with OS-supported change notifications, this can be
1297resource\-intensive. 1399resource\-intensive.
1298.PP 1400.PP
1299At the time of this writing, no specific \s-1OS\s0 backends are implemented, but 1401At the time of this writing, only the Linux inotify interface is
1300if demand increases, at least a kqueue and inotify backend will be added. 1402implemented (implementing kqueue support is left as an exercise for the
1403reader). Inotify will be used to give hints only and should not change the
1404semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometimes needs
1405to fall back to regular polling again even with inotify, but changes are
1406usually detected immediately, and if the file exists there will be no
1407polling.
1301.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 1408.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
1302.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 1409.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
1303.PD 0 1410.PD 0
1304.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 1411.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4
1305.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 1412.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)"
… …
1387.IX Item "ev_idle_init (ev_signal *, callback)" 1494.IX Item "ev_idle_init (ev_signal *, callback)"
1388Initialises and configures the idle watcher \- it has no parameters of any 1495Initialises and configures the idle watcher \- it has no parameters of any
1389kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, 1496kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
1390believe me. 1497believe me.
1391.PP 1498.PP
1392Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the 1499Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the
1393callback, free it. Alos, use no error checking, as usual. 1500callback, free it. Also, use no error checking, as usual.
1394.PP 1501.PP
1395.Vb 7 1502.Vb 7
1396\& static void 1503\& static void
1397\& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) 1504\& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
1398\& { 1505\& {
… …
2069otherwise another method will be used as fallback. This is the preferred 2176otherwise another method will be used as fallback. This is the preferred
2070backend for Solaris 10 systems. 2177backend for Solaris 10 systems.
2071.IP "\s-1EV_USE_DEVPOLL\s0" 4 2178.IP "\s-1EV_USE_DEVPOLL\s0" 4
2072.IX Item "EV_USE_DEVPOLL" 2179.IX Item "EV_USE_DEVPOLL"
2073reserved for future expansion, works like the \s-1USE\s0 symbols above. 2180reserved for future expansion, works like the \s-1USE\s0 symbols above.
2181.IP "\s-1EV_USE_INOTIFY\s0" 4
2182.IX Item "EV_USE_INOTIFY"
2183If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
2184interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will
2185be detected at runtime.
2074.IP "\s-1EV_H\s0" 4 2186.IP "\s-1EV_H\s0" 4
2075.IX Item "EV_H" 2187.IX Item "EV_H"
2076The name of the \fIev.h\fR header file used to include it. The default if 2188The name of the \fIev.h\fR header file used to include it. The default if
2077undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This 2189undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
2078can be used to virtually rename the \fIev.h\fR header file in case of conflicts. 2190can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
… …
2123.IP "\s-1EV_PID_HASHSIZE\s0" 4 2235.IP "\s-1EV_PID_HASHSIZE\s0" 4
2124.IX Item "EV_PID_HASHSIZE" 2236.IX Item "EV_PID_HASHSIZE"
2125\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by 2237\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
2126pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more 2238pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more
2127than enough. If you need to manage thousands of children you might want to 2239than enough. If you need to manage thousands of children you might want to
2128increase this value. 2240increase this value (\fImust\fR be a power of two).
2241.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
2242.IX Item "EV_INOTIFY_HASHSIZE"
2243\&\f(CW\*(C`ev_staz\*(C'\fR watchers use a small hash table to distribute workload by
2244inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR),
2245usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR
2246watchers you might want to increase this value (\fImust\fR be a power of
2247two).
2129.IP "\s-1EV_COMMON\s0" 4 2248.IP "\s-1EV_COMMON\s0" 4
2130.IX Item "EV_COMMON" 2249.IX Item "EV_COMMON"
2131By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining 2250By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
2132this macro to a something else you can include more and other types of 2251this macro to a something else you can include more and other types of
2133members. You have to define it each time you include one of the files, 2252members. You have to define it each time you include one of the files,
… …
2197.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 2316.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
2198.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 2317.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
2199.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" 2318.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
2200.IP "Stopping check/prepare/idle watchers: O(1)" 4 2319.IP "Stopping check/prepare/idle watchers: O(1)" 4
2201.IX Item "Stopping check/prepare/idle watchers: O(1)" 2320.IX Item "Stopping check/prepare/idle watchers: O(1)"
2202.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 2321.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
2203.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 2322.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
2204.IP "Finding the next timer per loop iteration: O(1)" 4 2323.IP "Finding the next timer per loop iteration: O(1)" 4
2205.IX Item "Finding the next timer per loop iteration: O(1)" 2324.IX Item "Finding the next timer per loop iteration: O(1)"
2206.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 2325.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
2207.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 2326.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
2208.IP "Activating one watcher: O(1)" 4 2327.IP "Activating one watcher: O(1)" 4

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