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Revision 1.23 by root, Tue Nov 27 08:20:42 2007 UTC vs.
Revision 1.28 by root, Tue Nov 27 20:26:50 2007 UTC

… …
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), relative timers (\f(CW\*(C`ev_timer\*(C'\fR),
159events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event 218absolute timers with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous
160loop mechanism itself (idle, prepare and check watchers). It also is quite 219signals (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and
161fast (see this benchmark comparing 220event watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR,
162it to libevent for example). 221\&\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
222file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events
223(\f(CW\*(C`ev_fork\*(C'\fR).
224.PP
225It also is quite fast (see this
226benchmark comparing it to libevent
227for example).
163.SH "CONVENTIONS" 228.SH "CONVENTIONS"
164.IX Header "CONVENTIONS" 229.IX Header "CONVENTIONS"
165Libev is very configurable. In this manual the default configuration 230Libev is very configurable. In this manual the default configuration will
166will be described, which supports multiple event loops. For more info 231be described, which supports multiple event loops. For more info about
167about various configuration options please have a look at the file 232various 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 233this manual. If libev was configured without support for multiple event
169support for multiple event loops, then all functions taking an initial 234loops, 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) 235(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" 236.SH "TIME REPRESENTATION"
173.IX Header "TIME REPRESENTATION" 237.IX Header "TIME REPRESENTATION"
174Libev represents time as a single floating point number, representing the 238Libev represents time as a single floating point number, representing the
175(fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near 239(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 240the 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, 265Usually, it's a good idea to terminate if the major versions mismatch,
202as this indicates an incompatible change. Minor versions are usually 266as this indicates an incompatible change. Minor versions are usually
203compatible to older versions, so a larger minor version alone is usually 267compatible to older versions, so a larger minor version alone is usually
204not a problem. 268not a problem.
205.Sp 269.Sp
206Example: make sure we haven't accidentally been linked against the wrong 270Example: Make sure we haven't accidentally been linked against the wrong
207version: 271version.
208.Sp 272.Sp
209.Vb 3 273.Vb 3
210\& assert (("libev version mismatch", 274\& assert (("libev version mismatch",
211\& ev_version_major () == EV_VERSION_MAJOR 275\& ev_version_major () == EV_VERSION_MAJOR
212\& && ev_version_minor () >= EV_VERSION_MINOR)); 276\& && ev_version_minor () >= EV_VERSION_MINOR));
… …
240might be supported on the current system, you would need to look at 304might 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 305\&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for
242recommended ones. 306recommended ones.
243.Sp 307.Sp
244See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. 308See 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))" 4 309.IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4
246.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" 310.IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))"
247Sets the allocation function to use (the prototype is similar to the 311Sets the allocation function to use (the prototype and semantics are
248realloc C function, the semantics are identical). It is used to allocate 312identical to the realloc C function). It is used to allocate and free
249and free memory (no surprises here). If it returns zero when memory 313memory (no surprises here). If it returns zero when memory needs to be
250needs to be allocated, the library might abort or take some potentially 314allocated, the library might abort or take some potentially destructive
251destructive action. The default is your system realloc function. 315action. The default is your system realloc function.
252.Sp 316.Sp
253You could override this function in high-availability programs to, say, 317You could override this function in high-availability programs to, say,
254free some memory if it cannot allocate memory, to use a special allocator, 318free 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. 319or even to sleep a while and retry until some memory is available.
256.Sp 320.Sp
257Example: replace the libev allocator with one that waits a bit and then 321Example: Replace the libev allocator with one that waits a bit and then
258retries: better than mine). 322retries).
259.Sp 323.Sp
260.Vb 6 324.Vb 6
261\& static void * 325\& static void *
262\& persistent_realloc (void *ptr, long size) 326\& persistent_realloc (void *ptr, size_t size)
263\& { 327\& {
264\& for (;;) 328\& for (;;)
265\& { 329\& {
266\& void *newptr = realloc (ptr, size); 330\& void *newptr = realloc (ptr, size);
267.Ve 331.Ve
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289callback is set, then libev will expect it to remedy the sitution, no 353callback is set, then libev will expect it to remedy the sitution, no
290matter what, when it returns. That is, libev will generally retry the 354matter what, when it returns. That is, libev will generally retry the
291requested operation, or, if the condition doesn't go away, do bad stuff 355requested operation, or, if the condition doesn't go away, do bad stuff
292(such as abort). 356(such as abort).
293.Sp 357.Sp
294Example: do the same thing as libev does internally: 358Example: This is basically the same thing that libev does internally, too.
295.Sp 359.Sp
296.Vb 6 360.Vb 6
297\& static void 361\& static void
298\& fatal_error (const char *msg) 362\& fatal_error (const char *msg)
299\& { 363\& {
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448Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is 512Similar 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 513always 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 514handle signal and child watchers, and attempts to do so will be greeted by
451undefined behaviour (or a failed assertion if assertions are enabled). 515undefined behaviour (or a failed assertion if assertions are enabled).
452.Sp 516.Sp
453Example: try to create a event loop that uses epoll and nothing else. 517Example: Try to create a event loop that uses epoll and nothing else.
454.Sp 518.Sp
455.Vb 3 519.Vb 3
456\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); 520\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
457\& if (!epoller) 521\& if (!epoller)
458\& fatal ("no epoll found here, maybe it hides under your chair"); 522\& fatal ("no epoll found here, maybe it hides under your chair");
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556\& be handled here by queueing them when their watcher gets executed. 620\& be handled here by queueing them when their watcher gets executed.
557\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK 621\& - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
558\& were used, return, otherwise continue with step *. 622\& were used, return, otherwise continue with step *.
559.Ve 623.Ve
560.Sp 624.Sp
561Example: queue some jobs and then loop until no events are outsanding 625Example: Queue some jobs and then loop until no events are outsanding
562anymore. 626anymore.
563.Sp 627.Sp
564.Vb 4 628.Vb 4
565\& ... queue jobs here, make sure they register event watchers as long 629\& ... 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..) 630\& ... as they still have work to do (even an idle watcher will do..)
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588visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from exiting if 652visible 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 653no 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 654way 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. 655libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
592.Sp 656.Sp
593Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR 657Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR
594running when nothing else is active. 658running when nothing else is active.
595.Sp 659.Sp
596.Vb 4 660.Vb 4
597\& struct dv_signal exitsig; 661\& struct ev_signal exitsig;
598\& ev_signal_init (&exitsig, sig_cb, SIGINT); 662\& ev_signal_init (&exitsig, sig_cb, SIGINT);
599\& ev_signal_start (myloop, &exitsig); 663\& ev_signal_start (loop, &exitsig);
600\& evf_unref (myloop); 664\& evf_unref (loop);
601.Ve 665.Ve
602.Sp 666.Sp
603Example: for some weird reason, unregister the above signal handler again. 667Example: For some weird reason, unregister the above signal handler again.
604.Sp 668.Sp
605.Vb 2 669.Vb 2
606\& ev_ref (myloop); 670\& ev_ref (loop);
607\& ev_signal_stop (myloop, &exitsig); 671\& ev_signal_stop (loop, &exitsig);
608.Ve 672.Ve
609.SH "ANATOMY OF A WATCHER" 673.SH "ANATOMY OF A WATCHER"
610.IX Header "ANATOMY OF A WATCHER" 674.IX Header "ANATOMY OF A WATCHER"
611A watcher is a structure that you create and register to record your 675A 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 676interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to
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707\&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any 771\&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any
708received events. Callbacks of both watcher types can start and stop as 772received events. Callbacks of both watcher types can start and stop as
709many watchers as they want, and all of them will be taken into account 773many watchers as they want, and all of them will be taken into account
710(for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep 774(for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep
711\&\f(CW\*(C`ev_loop\*(C'\fR from blocking). 775\&\f(CW\*(C`ev_loop\*(C'\fR from blocking).
776.ie n .IP """EV_EMBED""" 4
777.el .IP "\f(CWEV_EMBED\fR" 4
778.IX Item "EV_EMBED"
779The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention.
780.ie n .IP """EV_FORK""" 4
781.el .IP "\f(CWEV_FORK\fR" 4
782.IX Item "EV_FORK"
783The event loop has been resumed in the child process after fork (see
784\&\f(CW\*(C`ev_fork\*(C'\fR).
712.ie n .IP """EV_ERROR""" 4 785.ie n .IP """EV_ERROR""" 4
713.el .IP "\f(CWEV_ERROR\fR" 4 786.el .IP "\f(CWEV_ERROR\fR" 4
714.IX Item "EV_ERROR" 787.IX Item "EV_ERROR"
715An unspecified error has occured, the watcher has been stopped. This might 788An unspecified error has occured, the watcher has been stopped. This might
716happen because the watcher could not be properly started because libev 789happen because the watcher could not be properly started because libev
… …
892The file descriptor being watched. 965The file descriptor being watched.
893.IP "int events [read\-only]" 4 966.IP "int events [read\-only]" 4
894.IX Item "int events [read-only]" 967.IX Item "int events [read-only]"
895The events being watched. 968The events being watched.
896.PP 969.PP
897Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well 970Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
898readable, but only once. Since it is likely line\-buffered, you could 971readable, but only once. Since it is likely line\-buffered, you could
899attempt to read a whole line in the callback: 972attempt to read a whole line in the callback.
900.PP 973.PP
901.Vb 6 974.Vb 6
902\& static void 975\& static void
903\& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) 976\& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
904\& { 977\& {
… …
996.IX Item "ev_tstamp repeat [read-write]" 1069.IX Item "ev_tstamp repeat [read-write]"
997The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out 1070The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out
998or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), 1071or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any),
999which is also when any modifications are taken into account. 1072which is also when any modifications are taken into account.
1000.PP 1073.PP
1001Example: create a timer that fires after 60 seconds. 1074Example: Create a timer that fires after 60 seconds.
1002.PP 1075.PP
1003.Vb 5 1076.Vb 5
1004\& static void 1077\& static void
1005\& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1078\& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
1006\& { 1079\& {
… …
1012\& struct ev_timer mytimer; 1085\& struct ev_timer mytimer;
1013\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); 1086\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
1014\& ev_timer_start (loop, &mytimer); 1087\& ev_timer_start (loop, &mytimer);
1015.Ve 1088.Ve
1016.PP 1089.PP
1017Example: create a timeout timer that times out after 10 seconds of 1090Example: Create a timeout timer that times out after 10 seconds of
1018inactivity. 1091inactivity.
1019.PP 1092.PP
1020.Vb 5 1093.Vb 5
1021\& static void 1094\& static void
1022\& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) 1095\& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
… …
1147.IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" 1220.IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]"
1148The current reschedule callback, or \f(CW0\fR, if this functionality is 1221The current reschedule callback, or \f(CW0\fR, if this functionality is
1149switched off. Can be changed any time, but changes only take effect when 1222switched off. Can be changed any time, but changes only take effect when
1150the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. 1223the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
1151.PP 1224.PP
1152Example: call a callback every hour, or, more precisely, whenever the 1225Example: Call a callback every hour, or, more precisely, whenever the
1153system clock is divisible by 3600. The callback invocation times have 1226system clock is divisible by 3600. The callback invocation times have
1154potentially a lot of jittering, but good long-term stability. 1227potentially a lot of jittering, but good long-term stability.
1155.PP 1228.PP
1156.Vb 5 1229.Vb 5
1157\& static void 1230\& static void
… …
1165\& struct ev_periodic hourly_tick; 1238\& struct ev_periodic hourly_tick;
1166\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); 1239\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
1167\& ev_periodic_start (loop, &hourly_tick); 1240\& ev_periodic_start (loop, &hourly_tick);
1168.Ve 1241.Ve
1169.PP 1242.PP
1170Example: the same as above, but use a reschedule callback to do it: 1243Example: The same as above, but use a reschedule callback to do it:
1171.PP 1244.PP
1172.Vb 1 1245.Vb 1
1173\& #include <math.h> 1246\& #include <math.h>
1174.Ve 1247.Ve
1175.PP 1248.PP
… …
1183.PP 1256.PP
1184.Vb 1 1257.Vb 1
1185\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); 1258\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
1186.Ve 1259.Ve
1187.PP 1260.PP
1188Example: call a callback every hour, starting now: 1261Example: Call a callback every hour, starting now:
1189.PP 1262.PP
1190.Vb 4 1263.Vb 4
1191\& struct ev_periodic hourly_tick; 1264\& struct ev_periodic hourly_tick;
1192\& ev_periodic_init (&hourly_tick, clock_cb, 1265\& ev_periodic_init (&hourly_tick, clock_cb,
1193\& fmod (ev_now (loop), 3600.), 3600., 0); 1266\& fmod (ev_now (loop), 3600.), 3600., 0);
… …
1244.IP "int rstatus [read\-write]" 4 1317.IP "int rstatus [read\-write]" 4
1245.IX Item "int rstatus [read-write]" 1318.IX Item "int rstatus [read-write]"
1246The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems 1319The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems
1247\&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). 1320\&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details).
1248.PP 1321.PP
1249Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. 1322Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1250.PP 1323.PP
1251.Vb 5 1324.Vb 5
1252\& static void 1325\& static void
1253\& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) 1326\& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
1254\& { 1327\& {
… …
1378.IX Item "ev_idle_init (ev_signal *, callback)" 1451.IX Item "ev_idle_init (ev_signal *, callback)"
1379Initialises and configures the idle watcher \- it has no parameters of any 1452Initialises and configures the idle watcher \- it has no parameters of any
1380kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless, 1453kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
1381believe me. 1454believe me.
1382.PP 1455.PP
1383Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the 1456Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the
1384callback, free it. Alos, use no error checking, as usual. 1457callback, free it. Also, use no error checking, as usual.
1385.PP 1458.PP
1386.Vb 7 1459.Vb 7
1387\& static void 1460\& static void
1388\& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) 1461\& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
1389\& { 1462\& {
… …
1613similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most 1686similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most
1614apropriate way for embedded loops. 1687apropriate way for embedded loops.
1615.IP "struct ev_loop *loop [read\-only]" 4 1688.IP "struct ev_loop *loop [read\-only]" 4
1616.IX Item "struct ev_loop *loop [read-only]" 1689.IX Item "struct ev_loop *loop [read-only]"
1617The embedded event loop. 1690The embedded event loop.
1691.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
1692.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
1693.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
1694Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because
1695whoever is a good citizen cared to tell libev about it by calling
1696\&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the
1697event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called,
1698and only in the child after the fork. If whoever good citizen calling
1699\&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork
1700handlers will be invoked, too, of course.
1701.IP "ev_fork_init (ev_signal *, callback)" 4
1702.IX Item "ev_fork_init (ev_signal *, callback)"
1703Initialises and configures the fork watcher \- it has no parameters of any
1704kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless,
1705believe me.
1618.SH "OTHER FUNCTIONS" 1706.SH "OTHER FUNCTIONS"
1619.IX Header "OTHER FUNCTIONS" 1707.IX Header "OTHER FUNCTIONS"
1620There are some other functions of possible interest. Described. Here. Now. 1708There are some other functions of possible interest. Described. Here. Now.
1621.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 1709.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1622.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 1710.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
… …
1791\& : io (this, &myclass::io_cb), 1879\& : io (this, &myclass::io_cb),
1792\& idle (this, &myclass::idle_cb) 1880\& idle (this, &myclass::idle_cb)
1793\& { 1881\& {
1794\& io.start (fd, ev::READ); 1882\& io.start (fd, ev::READ);
1795\& } 1883\& }
1884.Ve
1885.SH "MACRO MAGIC"
1886.IX Header "MACRO MAGIC"
1887Libev can be compiled with a variety of options, the most fundemantal is
1888\&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and
1889callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument.
1890.PP
1891To make it easier to write programs that cope with either variant, the
1892following macros are defined:
1893.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
1894.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
1895.IX Item "EV_A, EV_A_"
1896This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
1897loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument,
1898\&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example:
1899.Sp
1900.Vb 3
1901\& ev_unref (EV_A);
1902\& ev_timer_add (EV_A_ watcher);
1903\& ev_loop (EV_A_ 0);
1904.Ve
1905.Sp
1906It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope,
1907which is often provided by the following macro.
1908.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
1909.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
1910.IX Item "EV_P, EV_P_"
1911This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
1912loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter,
1913\&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example:
1914.Sp
1915.Vb 2
1916\& // this is how ev_unref is being declared
1917\& static void ev_unref (EV_P);
1918.Ve
1919.Sp
1920.Vb 2
1921\& // this is how you can declare your typical callback
1922\& static void cb (EV_P_ ev_timer *w, int revents)
1923.Ve
1924.Sp
1925It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite
1926suitable for use with \f(CW\*(C`EV_A\*(C'\fR.
1927.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
1928.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
1929.IX Item "EV_DEFAULT, EV_DEFAULT_"
1930Similar to the other two macros, this gives you the value of the default
1931loop, if multiple loops are supported (\*(L"ev loop default\*(R").
1932.PP
1933Example: Declare and initialise a check watcher, working regardless of
1934wether multiple loops are supported or not.
1935.PP
1936.Vb 5
1937\& static void
1938\& check_cb (EV_P_ ev_timer *w, int revents)
1939\& {
1940\& ev_check_stop (EV_A_ w);
1941\& }
1942.Ve
1943.PP
1944.Vb 4
1945\& ev_check check;
1946\& ev_check_init (&check, check_cb);
1947\& ev_check_start (EV_DEFAULT_ &check);
1948\& ev_loop (EV_DEFAULT_ 0);
1796.Ve 1949.Ve
1797.SH "EMBEDDING" 1950.SH "EMBEDDING"
1798.IX Header "EMBEDDING" 1951.IX Header "EMBEDDING"
1799Libev can (and often is) directly embedded into host 1952Libev can (and often is) directly embedded into host
1800applications. Examples of applications that embed it include the Deliantra 1953applications. Examples of applications that embed it include the Deliantra
… …
2020defined to be \f(CW0\fR, then they are not. 2173defined to be \f(CW0\fR, then they are not.
2021.IP "\s-1EV_STAT_ENABLE\s0" 4 2174.IP "\s-1EV_STAT_ENABLE\s0" 4
2022.IX Item "EV_STAT_ENABLE" 2175.IX Item "EV_STAT_ENABLE"
2023If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If 2176If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
2024defined to be \f(CW0\fR, then they are not. 2177defined to be \f(CW0\fR, then they are not.
2178.IP "\s-1EV_FORK_ENABLE\s0" 4
2179.IX Item "EV_FORK_ENABLE"
2180If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
2181defined to be \f(CW0\fR, then they are not.
2025.IP "\s-1EV_MINIMAL\s0" 4 2182.IP "\s-1EV_MINIMAL\s0" 4
2026.IX Item "EV_MINIMAL" 2183.IX Item "EV_MINIMAL"
2027If you need to shave off some kilobytes of code at the expense of some 2184If you need to shave off some kilobytes of code at the expense of some
2028speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override 2185speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
2029some inlining decisions, saves roughly 30% codesize of amd64. 2186some inlining decisions, saves roughly 30% codesize of amd64.
2187.IP "\s-1EV_PID_HASHSIZE\s0" 4
2188.IX Item "EV_PID_HASHSIZE"
2189\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
2190pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more
2191than enough. If you need to manage thousands of children you might want to
2192increase this value.
2030.IP "\s-1EV_COMMON\s0" 4 2193.IP "\s-1EV_COMMON\s0" 4
2031.IX Item "EV_COMMON" 2194.IX Item "EV_COMMON"
2032By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining 2195By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
2033this macro to a something else you can include more and other types of 2196this macro to a something else you can include more and other types of
2034members. You have to define it each time you include one of the files, 2197members. You have to define it each time you include one of the files,

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