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Revision 1.14 by root, Sat Nov 24 10:10:26 2007 UTC vs.
Revision 1.23 by root, Tue Nov 27 08:20:42 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 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-11-27" "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
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684The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. 684The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread.
685.ie n .IP """EV_CHILD""" 4 685.ie n .IP """EV_CHILD""" 4
686.el .IP "\f(CWEV_CHILD\fR" 4 686.el .IP "\f(CWEV_CHILD\fR" 4
687.IX Item "EV_CHILD" 687.IX Item "EV_CHILD"
688The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. 688The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change.
689.ie n .IP """EV_STAT""" 4
690.el .IP "\f(CWEV_STAT\fR" 4
691.IX Item "EV_STAT"
692The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow.
689.ie n .IP """EV_IDLE""" 4 693.ie n .IP """EV_IDLE""" 4
690.el .IP "\f(CWEV_IDLE\fR" 4 694.el .IP "\f(CWEV_IDLE\fR" 4
691.IX Item "EV_IDLE" 695.IX Item "EV_IDLE"
692The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. 696The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do.
693.ie n .IP """EV_PREPARE""" 4 697.ie n .IP """EV_PREPARE""" 4
… …
717Libev will usually signal a few \*(L"dummy\*(R" events together with an error, 721Libev will usually signal a few \*(L"dummy\*(R" events together with an error,
718for example it might indicate that a fd is readable or writable, and if 722for example it might indicate that a fd is readable or writable, and if
719your callbacks is well-written it can just attempt the operation and cope 723your callbacks is well-written it can just attempt the operation and cope
720with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded 724with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded
721programs, though, so beware. 725programs, though, so beware.
722.Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" 726.Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0"
723.IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS" 727.IX Subsection "GENERIC WATCHER FUNCTIONS"
724In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, 728In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type,
725e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. 729e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers.
726.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 730.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
727.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 731.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
728.IX Item "ev_init (ev_TYPE *watcher, callback)" 732.IX Item "ev_init (ev_TYPE *watcher, callback)"
… …
734which rolls both calls into one. 738which rolls both calls into one.
735.Sp 739.Sp
736You can reinitialise a watcher at any time as long as it has been stopped 740You can reinitialise a watcher at any time as long as it has been stopped
737(or never started) and there are no pending events outstanding. 741(or never started) and there are no pending events outstanding.
738.Sp 742.Sp
739The callbakc is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, 743The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher,
740int revents)\*(C'\fR. 744int revents)\*(C'\fR.
741.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 745.ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4
742.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 746.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4
743.IX Item "ev_TYPE_set (ev_TYPE *, [args])" 747.IX Item "ev_TYPE_set (ev_TYPE *, [args])"
744This macro initialises the type-specific parts of a watcher. You need to 748This macro initialises the type-specific parts of a watcher. You need to
… …
821More interesting and less C\-conformant ways of catsing your callback type 825More interesting and less C\-conformant ways of catsing your callback type
822have been omitted.... 826have been omitted....
823.SH "WATCHER TYPES" 827.SH "WATCHER TYPES"
824.IX Header "WATCHER TYPES" 828.IX Header "WATCHER TYPES"
825This section describes each watcher in detail, but will not repeat 829This section describes each watcher in detail, but will not repeat
826information given in the last section. 830information given in the last section. Any initialisation/set macros,
831functions and members specific to the watcher type are explained.
832.PP
833Members are additionally marked with either \fI[read\-only]\fR, meaning that,
834while the watcher is active, you can look at the member and expect some
835sensible content, but you must not modify it (you can modify it while the
836watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
837means you can expect it to have some sensible content while the watcher
838is active, but you can also modify it. Modifying it may not do something
839sensible or take immediate effect (or do anything at all), but libev will
840not crash or malfunction in any way.
827.ie n .Sh """ev_io"" \- is this file descriptor readable or writable" 841.ie n .Sh """ev_io"" \- is this file descriptor readable or writable?"
828.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" 842.el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?"
829.IX Subsection "ev_io - is this file descriptor readable or writable" 843.IX Subsection "ev_io - is this file descriptor readable or writable?"
830I/O watchers check whether a file descriptor is readable or writable 844I/O watchers check whether a file descriptor is readable or writable
831in each iteration of the event loop (This behaviour is called 845in each iteration of the event loop, or, more precisely, when reading
832level-triggering because you keep receiving events as long as the 846would not block the process and writing would at least be able to write
833condition persists. Remember you can stop the watcher if you don't want to 847some data. This behaviour is called level-triggering because you keep
834act on the event and neither want to receive future events). 848receiving events as long as the condition persists. Remember you can stop
849the watcher if you don't want to act on the event and neither want to
850receive future events.
835.PP 851.PP
836In general you can register as many read and/or write event watchers per 852In general you can register as many read and/or write event watchers per
837fd as you want (as long as you don't confuse yourself). Setting all file 853fd as you want (as long as you don't confuse yourself). Setting all file
838descriptors to non-blocking mode is also usually a good idea (but not 854descriptors to non-blocking mode is also usually a good idea (but not
839required if you know what you are doing). 855required if you know what you are doing).
840.PP 856.PP
841You have to be careful with dup'ed file descriptors, though. Some backends 857You have to be careful with dup'ed file descriptors, though. Some backends
842(the linux epoll backend is a notable example) cannot handle dup'ed file 858(the linux epoll backend is a notable example) cannot handle dup'ed file
843descriptors correctly if you register interest in two or more fds pointing 859descriptors correctly if you register interest in two or more fds pointing
844to the same underlying file/socket etc. description (that is, they share 860to the same underlying file/socket/etc. description (that is, they share
845the same underlying \*(L"file open\*(R"). 861the same underlying \*(L"file open\*(R").
846.PP 862.PP
847If you must do this, then force the use of a known-to-be-good backend 863If you must do this, then force the use of a known-to-be-good backend
848(at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and 864(at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and
849\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). 865\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR).
866.PP
867Another thing you have to watch out for is that it is quite easy to
868receive \*(L"spurious\*(R" readyness notifications, that is your callback might
869be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block
870because there is no data. Not only are some backends known to create a
871lot of those (for example solaris ports), it is very easy to get into
872this situation even with a relatively standard program structure. Thus
873it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning
874\&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives.
875.PP
876If you cannot run the fd in non-blocking mode (for example you should not
877play around with an Xlib connection), then you have to seperately re-test
878wether a file descriptor is really ready with a known-to-be good interface
879such as poll (fortunately in our Xlib example, Xlib already does this on
880its own, so its quite safe to use).
850.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 881.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
851.IX Item "ev_io_init (ev_io *, callback, int fd, int events)" 882.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
852.PD 0 883.PD 0
853.IP "ev_io_set (ev_io *, int fd, int events)" 4 884.IP "ev_io_set (ev_io *, int fd, int events)" 4
854.IX Item "ev_io_set (ev_io *, int fd, int events)" 885.IX Item "ev_io_set (ev_io *, int fd, int events)"
855.PD 886.PD
856Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive 887Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to
857events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_READ | 888rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or
858EV_WRITE\*(C'\fR to receive the given events. 889\&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events.
859.Sp 890.IP "int fd [read\-only]" 4
860Please note that most of the more scalable backend mechanisms (for example 891.IX Item "int fd [read-only]"
861epoll and solaris ports) can result in spurious readyness notifications 892The file descriptor being watched.
862for file descriptors, so you practically need to use non-blocking I/O (and 893.IP "int events [read\-only]" 4
863treat callback invocation as hint only), or retest separately with a safe 894.IX Item "int events [read-only]"
864interface before doing I/O (XLib can do this), or force the use of either 895The events being watched.
865\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this
866problem. Also note that it is quite easy to have your callback invoked
867when the readyness condition is no longer valid even when employing
868typical ways of handling events, so its a good idea to use non-blocking
869I/O unconditionally.
870.PP 896.PP
871Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well 897Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
872readable, but only once. Since it is likely line\-buffered, you could 898readable, but only once. Since it is likely line\-buffered, you could
873attempt to read a whole line in the callback: 899attempt to read a whole line in the callback:
874.PP 900.PP
… …
887\& struct ev_io stdin_readable; 913\& struct ev_io stdin_readable;
888\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); 914\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
889\& ev_io_start (loop, &stdin_readable); 915\& ev_io_start (loop, &stdin_readable);
890\& ev_loop (loop, 0); 916\& ev_loop (loop, 0);
891.Ve 917.Ve
892.ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" 918.ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts"
893.el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" 919.el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
894.IX Subsection "ev_timer - relative and optionally recurring timeouts" 920.IX Subsection "ev_timer - relative and optionally repeating timeouts"
895Timer watchers are simple relative timers that generate an event after a 921Timer watchers are simple relative timers that generate an event after a
896given time, and optionally repeating in regular intervals after that. 922given time, and optionally repeating in regular intervals after that.
897.PP 923.PP
898The timers are based on real time, that is, if you register an event that 924The timers are based on real time, that is, if you register an event that
899times out after an hour and you reset your system clock to last years 925times out after an hour and you reset your system clock to last years
… …
939.Sp 965.Sp
940If the timer is repeating, either start it if necessary (with the repeat 966If the timer is repeating, either start it if necessary (with the repeat
941value), or reset the running timer to the repeat value. 967value), or reset the running timer to the repeat value.
942.Sp 968.Sp
943This sounds a bit complicated, but here is a useful and typical 969This sounds a bit complicated, but here is a useful and typical
944example: Imagine you have a tcp connection and you want a so-called idle 970example: Imagine you have a tcp connection and you want a so-called
945timeout, that is, you want to be called when there have been, say, 60 971idle timeout, that is, you want to be called when there have been,
946seconds of inactivity on the socket. The easiest way to do this is to 972say, 60 seconds of inactivity on the socket. The easiest way to do
947configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each 973this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling
948time you successfully read or write some data. If you go into an idle 974\&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If
949state where you do not expect data to travel on the socket, you can stop 975you go into an idle state where you do not expect data to travel on the
950the timer, and again will automatically restart it if need be. 976socket, you can stop the timer, and again will automatically restart it if
977need be.
978.Sp
979You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether
980and only ever use the \f(CW\*(C`repeat\*(C'\fR value:
981.Sp
982.Vb 8
983\& ev_timer_init (timer, callback, 0., 5.);
984\& ev_timer_again (loop, timer);
985\& ...
986\& timer->again = 17.;
987\& ev_timer_again (loop, timer);
988\& ...
989\& timer->again = 10.;
990\& ev_timer_again (loop, timer);
991.Ve
992.Sp
993This is more efficient then stopping/starting the timer eahc time you want
994to modify its timeout value.
995.IP "ev_tstamp repeat [read\-write]" 4
996.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
998or \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.
951.PP 1000.PP
952Example: create a timer that fires after 60 seconds. 1001Example: create a timer that fires after 60 seconds.
953.PP 1002.PP
954.Vb 5 1003.Vb 5
955\& static void 1004\& static void
… …
986.Vb 3 1035.Vb 3
987\& // and in some piece of code that gets executed on any "activity": 1036\& // and in some piece of code that gets executed on any "activity":
988\& // reset the timeout to start ticking again at 10 seconds 1037\& // reset the timeout to start ticking again at 10 seconds
989\& ev_timer_again (&mytimer); 1038\& ev_timer_again (&mytimer);
990.Ve 1039.Ve
991.ie n .Sh """ev_periodic"" \- to cron or not to cron" 1040.ie n .Sh """ev_periodic"" \- to cron or not to cron?"
992.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" 1041.el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?"
993.IX Subsection "ev_periodic - to cron or not to cron" 1042.IX Subsection "ev_periodic - to cron or not to cron?"
994Periodic watchers are also timers of a kind, but they are very versatile 1043Periodic watchers are also timers of a kind, but they are very versatile
995(and unfortunately a bit complex). 1044(and unfortunately a bit complex).
996.PP 1045.PP
997Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) 1046Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time)
998but on wallclock time (absolute time). You can tell a periodic watcher 1047but on wallclock time (absolute time). You can tell a periodic watcher
… …
1087.IX Item "ev_periodic_again (loop, ev_periodic *)" 1136.IX Item "ev_periodic_again (loop, ev_periodic *)"
1088Simply stops and restarts the periodic watcher again. This is only useful 1137Simply stops and restarts the periodic watcher again. This is only useful
1089when you changed some parameters or the reschedule callback would return 1138when you changed some parameters or the reschedule callback would return
1090a different time than the last time it was called (e.g. in a crond like 1139a different time than the last time it was called (e.g. in a crond like
1091program when the crontabs have changed). 1140program when the crontabs have changed).
1141.IP "ev_tstamp interval [read\-write]" 4
1142.IX Item "ev_tstamp interval [read-write]"
1143The current interval value. Can be modified any time, but changes only
1144take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being
1145called.
1146.IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4
1147.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
1149switched 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.
1092.PP 1151.PP
1093Example: call a callback every hour, or, more precisely, whenever the 1152Example: call a callback every hour, or, more precisely, whenever the
1094system clock is divisible by 3600. The callback invocation times have 1153system clock is divisible by 3600. The callback invocation times have
1095potentially a lot of jittering, but good long-term stability. 1154potentially a lot of jittering, but good long-term stability.
1096.PP 1155.PP
… …
1132\& struct ev_periodic hourly_tick; 1191\& struct ev_periodic hourly_tick;
1133\& ev_periodic_init (&hourly_tick, clock_cb, 1192\& ev_periodic_init (&hourly_tick, clock_cb,
1134\& fmod (ev_now (loop), 3600.), 3600., 0); 1193\& fmod (ev_now (loop), 3600.), 3600., 0);
1135\& ev_periodic_start (loop, &hourly_tick); 1194\& ev_periodic_start (loop, &hourly_tick);
1136.Ve 1195.Ve
1137.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" 1196.ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!"
1138.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" 1197.el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!"
1139.IX Subsection "ev_signal - signal me when a signal gets signalled" 1198.IX Subsection "ev_signal - signal me when a signal gets signalled!"
1140Signal watchers will trigger an event when the process receives a specific 1199Signal watchers will trigger an event when the process receives a specific
1141signal one or more times. Even though signals are very asynchronous, libev 1200signal one or more times. Even though signals are very asynchronous, libev
1142will try it's best to deliver signals synchronously, i.e. as part of the 1201will try it's best to deliver signals synchronously, i.e. as part of the
1143normal event processing, like any other event. 1202normal event processing, like any other event.
1144.PP 1203.PP
… …
1154.IP "ev_signal_set (ev_signal *, int signum)" 4 1213.IP "ev_signal_set (ev_signal *, int signum)" 4
1155.IX Item "ev_signal_set (ev_signal *, int signum)" 1214.IX Item "ev_signal_set (ev_signal *, int signum)"
1156.PD 1215.PD
1157Configures the watcher to trigger on the given signal number (usually one 1216Configures the watcher to trigger on the given signal number (usually one
1158of the \f(CW\*(C`SIGxxx\*(C'\fR constants). 1217of the \f(CW\*(C`SIGxxx\*(C'\fR constants).
1218.IP "int signum [read\-only]" 4
1219.IX Item "int signum [read-only]"
1220The signal the watcher watches out for.
1159.ie n .Sh """ev_child"" \- wait for pid status changes" 1221.ie n .Sh """ev_child"" \- watch out for process status changes"
1160.el .Sh "\f(CWev_child\fP \- wait for pid status changes" 1222.el .Sh "\f(CWev_child\fP \- watch out for process status changes"
1161.IX Subsection "ev_child - wait for pid status changes" 1223.IX Subsection "ev_child - watch out for process status changes"
1162Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to 1224Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
1163some child status changes (most typically when a child of yours dies). 1225some child status changes (most typically when a child of yours dies).
1164.IP "ev_child_init (ev_child *, callback, int pid)" 4 1226.IP "ev_child_init (ev_child *, callback, int pid)" 4
1165.IX Item "ev_child_init (ev_child *, callback, int pid)" 1227.IX Item "ev_child_init (ev_child *, callback, int pid)"
1166.PD 0 1228.PD 0
… …
1171\&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look 1233\&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look
1172at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see 1234at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see
1173the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems 1235the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems
1174\&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the 1236\&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the
1175process causing the status change. 1237process causing the status change.
1238.IP "int pid [read\-only]" 4
1239.IX Item "int pid [read-only]"
1240The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
1241.IP "int rpid [read\-write]" 4
1242.IX Item "int rpid [read-write]"
1243The process id that detected a status change.
1244.IP "int rstatus [read\-write]" 4
1245.IX Item "int rstatus [read-write]"
1246The 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).
1176.PP 1248.PP
1177Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. 1249Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
1178.PP 1250.PP
1179.Vb 5 1251.Vb 5
1180\& static void 1252\& static void
… …
1187.Vb 3 1259.Vb 3
1188\& struct ev_signal signal_watcher; 1260\& struct ev_signal signal_watcher;
1189\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); 1261\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
1190\& ev_signal_start (loop, &sigint_cb); 1262\& ev_signal_start (loop, &sigint_cb);
1191.Ve 1263.Ve
1264.ie n .Sh """ev_stat"" \- did the file attributes just change?"
1265.el .Sh "\f(CWev_stat\fP \- did the file attributes just change?"
1266.IX Subsection "ev_stat - did the file attributes just change?"
1267This watches a filesystem path for attribute changes. That is, it calls
1268\&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed
1269compared to the last time, invoking the callback if it did.
1270.PP
1271The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does
1272not exist\*(R" is a status change like any other. The condition \*(L"path does
1273not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is
1274otherwise always forced to be at least one) and all the other fields of
1275the stat buffer having unspecified contents.
1276.PP
1277Since there is no standard to do this, the portable implementation simply
1278calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You
1279can specify a recommended polling interval for this case. If you specify
1280a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,
1281unspecified default\fR value will be used (which you can expect to be around
1282five seconds, although this might change dynamically). Libev will also
1283impose a minimum interval which is currently around \f(CW0.1\fR, but thats
1284usually overkill.
1285.PP
1286This watcher type is not meant for massive numbers of stat watchers,
1287as even with OS-supported change notifications, this can be
1288resource\-intensive.
1289.PP
1290At the time of this writing, no specific \s-1OS\s0 backends are implemented, but
1291if demand increases, at least a kqueue and inotify backend will be added.
1292.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
1293.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
1294.PD 0
1295.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4
1296.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)"
1297.PD
1298Configures the watcher to wait for status changes of the given
1299\&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to
1300be detected and should normally be specified as \f(CW0\fR to let libev choose
1301a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same
1302path for as long as the watcher is active.
1303.Sp
1304The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected,
1305relative to the attributes at the time the watcher was started (or the
1306last change was detected).
1307.IP "ev_stat_stat (ev_stat *)" 4
1308.IX Item "ev_stat_stat (ev_stat *)"
1309Updates the stat buffer immediately with new values. If you change the
1310watched path in your callback, you could call this fucntion to avoid
1311detecting this change (while introducing a race condition). Can also be
1312useful simply to find out the new values.
1313.IP "ev_statdata attr [read\-only]" 4
1314.IX Item "ev_statdata attr [read-only]"
1315The most-recently detected attributes of the file. Although the type is of
1316\&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types
1317suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there
1318was some error while \f(CW\*(C`stat\*(C'\fRing the file.
1319.IP "ev_statdata prev [read\-only]" 4
1320.IX Item "ev_statdata prev [read-only]"
1321The previous attributes of the file. The callback gets invoked whenever
1322\&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR.
1323.IP "ev_tstamp interval [read\-only]" 4
1324.IX Item "ev_tstamp interval [read-only]"
1325The specified interval.
1326.IP "const char *path [read\-only]" 4
1327.IX Item "const char *path [read-only]"
1328The filesystem path that is being watched.
1329.PP
1330Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes.
1331.PP
1332.Vb 15
1333\& static void
1334\& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
1335\& {
1336\& /* /etc/passwd changed in some way */
1337\& if (w->attr.st_nlink)
1338\& {
1339\& printf ("passwd current size %ld\en", (long)w->attr.st_size);
1340\& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime);
1341\& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime);
1342\& }
1343\& else
1344\& /* you shalt not abuse printf for puts */
1345\& puts ("wow, /etc/passwd is not there, expect problems. "
1346\& "if this is windows, they already arrived\en");
1347\& }
1348.Ve
1349.PP
1350.Vb 2
1351\& ...
1352\& ev_stat passwd;
1353.Ve
1354.PP
1355.Vb 2
1356\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd");
1357\& ev_stat_start (loop, &passwd);
1358.Ve
1192.ie n .Sh """ev_idle"" \- when you've got nothing better to do" 1359.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
1193.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" 1360.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
1194.IX Subsection "ev_idle - when you've got nothing better to do" 1361.IX Subsection "ev_idle - when you've got nothing better to do..."
1195Idle watchers trigger events when there are no other events are pending 1362Idle watchers trigger events when there are no other events are pending
1196(prepare, check and other idle watchers do not count). That is, as long 1363(prepare, check and other idle watchers do not count). That is, as long
1197as your process is busy handling sockets or timeouts (or even signals, 1364as your process is busy handling sockets or timeouts (or even signals,
1198imagine) it will not be triggered. But when your process is idle all idle 1365imagine) it will not be triggered. But when your process is idle all idle
1199watchers are being called again and again, once per event loop iteration \- 1366watchers are being called again and again, once per event loop iteration \-
… …
1229.Vb 3 1396.Vb 3
1230\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); 1397\& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle));
1231\& ev_idle_init (idle_watcher, idle_cb); 1398\& ev_idle_init (idle_watcher, idle_cb);
1232\& ev_idle_start (loop, idle_cb); 1399\& ev_idle_start (loop, idle_cb);
1233.Ve 1400.Ve
1234.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" 1401.ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!"
1235.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" 1402.el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
1236.IX Subsection "ev_prepare and ev_check - customise your event loop" 1403.IX Subsection "ev_prepare and ev_check - customise your event loop!"
1237Prepare and check watchers are usually (but not always) used in tandem: 1404Prepare and check watchers are usually (but not always) used in tandem:
1238prepare watchers get invoked before the process blocks and check watchers 1405prepare watchers get invoked before the process blocks and check watchers
1239afterwards. 1406afterwards.
1240.PP 1407.PP
1408You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter
1409the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR
1410watchers. Other loops than the current one are fine, however. The
1411rationale behind this is that you do not need to check for recursion in
1412those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking,
1413\&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be
1414called in pairs bracketing the blocking call.
1415.PP
1241Their main purpose is to integrate other event mechanisms into libev and 1416Their main purpose is to integrate other event mechanisms into libev and
1242their use is somewhat advanced. This could be used, for example, to track 1417their use is somewhat advanced. This could be used, for example, to track
1243variable changes, implement your own watchers, integrate net-snmp or a 1418variable changes, implement your own watchers, integrate net-snmp or a
1244coroutine library and lots more. 1419coroutine library and lots more. They are also occasionally useful if
1420you cache some data and want to flush it before blocking (for example,
1421in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR
1422watcher).
1245.PP 1423.PP
1246This is done by examining in each prepare call which file descriptors need 1424This is done by examining in each prepare call which file descriptors need
1247to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for 1425to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for
1248them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries 1426them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries
1249provide just this functionality). Then, in the check watcher you check for 1427provide just this functionality). Then, in the check watcher you check for
… …
1268.PD 1446.PD
1269Initialises and configures the prepare or check watcher \- they have no 1447Initialises and configures the prepare or check watcher \- they have no
1270parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR 1448parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR
1271macros, but using them is utterly, utterly and completely pointless. 1449macros, but using them is utterly, utterly and completely pointless.
1272.PP 1450.PP
1273Example: *TODO*. 1451Example: To include a library such as adns, you would add \s-1IO\s0 watchers
1452and a timeout watcher in a prepare handler, as required by libadns, and
1453in a check watcher, destroy them and call into libadns. What follows is
1454pseudo-code only of course:
1455.PP
1456.Vb 2
1457\& static ev_io iow [nfd];
1458\& static ev_timer tw;
1459.Ve
1460.PP
1461.Vb 9
1462\& static void
1463\& io_cb (ev_loop *loop, ev_io *w, int revents)
1464\& {
1465\& // set the relevant poll flags
1466\& // could also call adns_processreadable etc. here
1467\& struct pollfd *fd = (struct pollfd *)w->data;
1468\& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1469\& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
1470\& }
1471.Ve
1472.PP
1473.Vb 7
1474\& // create io watchers for each fd and a timer before blocking
1475\& static void
1476\& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)
1477\& {
1478\& int timeout = 3600000;truct pollfd fds [nfd];
1479\& // actual code will need to loop here and realloc etc.
1480\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1481.Ve
1482.PP
1483.Vb 3
1484\& /* the callback is illegal, but won't be called as we stop during check */
1485\& ev_timer_init (&tw, 0, timeout * 1e-3);
1486\& ev_timer_start (loop, &tw);
1487.Ve
1488.PP
1489.Vb 6
1490\& // create on ev_io per pollfd
1491\& for (int i = 0; i < nfd; ++i)
1492\& {
1493\& ev_io_init (iow + i, io_cb, fds [i].fd,
1494\& ((fds [i].events & POLLIN ? EV_READ : 0)
1495\& | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1496.Ve
1497.PP
1498.Vb 5
1499\& fds [i].revents = 0;
1500\& iow [i].data = fds + i;
1501\& ev_io_start (loop, iow + i);
1502\& }
1503\& }
1504.Ve
1505.PP
1506.Vb 5
1507\& // stop all watchers after blocking
1508\& static void
1509\& adns_check_cb (ev_loop *loop, ev_check *w, int revents)
1510\& {
1511\& ev_timer_stop (loop, &tw);
1512.Ve
1513.PP
1514.Vb 2
1515\& for (int i = 0; i < nfd; ++i)
1516\& ev_io_stop (loop, iow + i);
1517.Ve
1518.PP
1519.Vb 2
1520\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
1521\& }
1522.Ve
1274.ie n .Sh """ev_embed"" \- when one backend isn't enough" 1523.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1275.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough" 1524.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1276.IX Subsection "ev_embed - when one backend isn't enough" 1525.IX Subsection "ev_embed - when one backend isn't enough..."
1277This is a rather advanced watcher type that lets you embed one event loop 1526This is a rather advanced watcher type that lets you embed one event loop
1278into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded 1527into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded
1279loop, other types of watchers might be handled in a delayed or incorrect 1528loop, other types of watchers might be handled in a delayed or incorrect
1280fashion and must not be used). 1529fashion and must not be used).
1281.PP 1530.PP
… …
1361.IP "ev_embed_sweep (loop, ev_embed *)" 4 1610.IP "ev_embed_sweep (loop, ev_embed *)" 4
1362.IX Item "ev_embed_sweep (loop, ev_embed *)" 1611.IX Item "ev_embed_sweep (loop, ev_embed *)"
1363Make a single, non-blocking sweep over the embedded loop. This works 1612Make a single, non-blocking sweep over the embedded loop. This works
1364similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most 1613similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most
1365apropriate way for embedded loops. 1614apropriate way for embedded loops.
1615.IP "struct ev_loop *loop [read\-only]" 4
1616.IX Item "struct ev_loop *loop [read-only]"
1617The embedded event loop.
1366.SH "OTHER FUNCTIONS" 1618.SH "OTHER FUNCTIONS"
1367.IX Header "OTHER FUNCTIONS" 1619.IX Header "OTHER FUNCTIONS"
1368There are some other functions of possible interest. Described. Here. Now. 1620There are some other functions of possible interest. Described. Here. Now.
1369.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 1621.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
1370.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 1622.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
… …
1509\&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. 1761\&\f(CW\*(C`ev_TYPE_again\*(C'\fR function.
1510.ie n .IP "w\->sweep () ""ev::embed"" only" 4 1762.ie n .IP "w\->sweep () ""ev::embed"" only" 4
1511.el .IP "w\->sweep () \f(CWev::embed\fR only" 4 1763.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
1512.IX Item "w->sweep () ev::embed only" 1764.IX Item "w->sweep () ev::embed only"
1513Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. 1765Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR.
1766.ie n .IP "w\->update () ""ev::stat"" only" 4
1767.el .IP "w\->update () \f(CWev::stat\fR only" 4
1768.IX Item "w->update () ev::stat only"
1769Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR.
1514.RE 1770.RE
1515.RS 4 1771.RS 4
1516.RE 1772.RE
1517.PP 1773.PP
1518Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in 1774Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
… …
1593.Vb 1 1849.Vb 1
1594\& ev_win32.c required on win32 platforms only 1850\& ev_win32.c required on win32 platforms only
1595.Ve 1851.Ve
1596.PP 1852.PP
1597.Vb 5 1853.Vb 5
1598\& ev_select.c only when select backend is enabled (which is is by default) 1854\& ev_select.c only when select backend is enabled (which is by default)
1599\& ev_poll.c only when poll backend is enabled (disabled by default) 1855\& ev_poll.c only when poll backend is enabled (disabled by default)
1600\& ev_epoll.c only when the epoll backend is enabled (disabled by default) 1856\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
1601\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) 1857\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1602\& ev_port.c only when the solaris port backend is enabled (disabled by default) 1858\& ev_port.c only when the solaris port backend is enabled (disabled by default)
1603.Ve 1859.Ve
1604.PP 1860.PP
1605\&\fIev.c\fR includes the backend files directly when enabled, so you only need 1861\&\fIev.c\fR includes the backend files directly when enabled, so you only need
1606to compile a single file. 1862to compile this single file.
1607.PP 1863.PP
1608\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR 1864\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
1609.IX Subsection "LIBEVENT COMPATIBILITY API" 1865.IX Subsection "LIBEVENT COMPATIBILITY API"
1610.PP 1866.PP
1611To include the libevent compatibility \s-1API\s0, also include: 1867To include the libevent compatibility \s-1API\s0, also include:
… …
1632\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR 1888\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
1633.IX Subsection "AUTOCONF SUPPORT" 1889.IX Subsection "AUTOCONF SUPPORT"
1634.PP 1890.PP
1635Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in 1891Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in
1636whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your 1892whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your
1637\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR off. \fIev.c\fR will then include 1893\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then
1638\&\fIconfig.h\fR and configure itself accordingly. 1894include \fIconfig.h\fR and configure itself accordingly.
1639.PP 1895.PP
1640For this of course you need the m4 file: 1896For this of course you need the m4 file:
1641.PP 1897.PP
1642.Vb 1 1898.Vb 1
1643\& libev.m4 1899\& libev.m4
… …
1713otherwise another method will be used as fallback. This is the preferred 1969otherwise another method will be used as fallback. This is the preferred
1714backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only 1970backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
1715supports some types of fds correctly (the only platform we found that 1971supports some types of fds correctly (the only platform we found that
1716supports ptys for example was NetBSD), so kqueue might be compiled in, but 1972supports ptys for example was NetBSD), so kqueue might be compiled in, but
1717not be used unless explicitly requested. The best way to use it is to find 1973not be used unless explicitly requested. The best way to use it is to find
1718out wether kqueue supports your type of fd properly and use an embedded 1974out whether kqueue supports your type of fd properly and use an embedded
1719kqueue loop. 1975kqueue loop.
1720.IP "\s-1EV_USE_PORT\s0" 4 1976.IP "\s-1EV_USE_PORT\s0" 4
1721.IX Item "EV_USE_PORT" 1977.IX Item "EV_USE_PORT"
1722If defined to be \f(CW1\fR, libev will compile in support for the Solaris 1978If defined to be \f(CW1\fR, libev will compile in support for the Solaris
172310 port style backend. Its availability will be detected at runtime, 197910 port style backend. Its availability will be detected at runtime,
… …
1751If undefined or defined to \f(CW1\fR, then all event-loop-specific functions 2007If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
1752will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create 2008will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create
1753additional independent event loops. Otherwise there will be no support 2009additional independent event loops. Otherwise there will be no support
1754for multiple event loops and there is no first event loop pointer 2010for multiple event loops and there is no first event loop pointer
1755argument. Instead, all functions act on the single default loop. 2011argument. Instead, all functions act on the single default loop.
1756.IP "\s-1EV_PERIODICS\s0" 4 2012.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
1757.IX Item "EV_PERIODICS" 2013.IX Item "EV_PERIODIC_ENABLE"
1758If undefined or defined to be \f(CW1\fR, then periodic timers are supported, 2014If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
1759otherwise not. This saves a few kb of code. 2015defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
2016code.
2017.IP "\s-1EV_EMBED_ENABLE\s0" 4
2018.IX Item "EV_EMBED_ENABLE"
2019If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
2020defined to be \f(CW0\fR, then they are not.
2021.IP "\s-1EV_STAT_ENABLE\s0" 4
2022.IX Item "EV_STAT_ENABLE"
2023If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
2024defined to be \f(CW0\fR, then they are not.
2025.IP "\s-1EV_MINIMAL\s0" 4
2026.IX Item "EV_MINIMAL"
2027If 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
2029some inlining decisions, saves roughly 30% codesize of amd64.
1760.IP "\s-1EV_COMMON\s0" 4 2030.IP "\s-1EV_COMMON\s0" 4
1761.IX Item "EV_COMMON" 2031.IX Item "EV_COMMON"
1762By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining 2032By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
1763this macro to a something else you can include more and other types of 2033this macro to a something else you can include more and other types of
1764members. You have to define it each time you include one of the files, 2034members. You have to define it each time you include one of the files,
… …
1769.Vb 3 2039.Vb 3
1770\& #define EV_COMMON \e 2040\& #define EV_COMMON \e
1771\& SV *self; /* contains this struct */ \e 2041\& SV *self; /* contains this struct */ \e
1772\& SV *cb_sv, *fh /* note no trailing ";" */ 2042\& SV *cb_sv, *fh /* note no trailing ";" */
1773.Ve 2043.Ve
1774.IP "\s-1EV_CB_DECLARE\s0(type)" 4 2044.IP "\s-1EV_CB_DECLARE\s0 (type)" 4
1775.IX Item "EV_CB_DECLARE(type)" 2045.IX Item "EV_CB_DECLARE (type)"
1776.PD 0 2046.PD 0
1777.IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4 2047.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4
1778.IX Item "EV_CB_INVOKE(watcher,revents)" 2048.IX Item "EV_CB_INVOKE (watcher, revents)"
1779.IP "ev_set_cb(ev,cb)" 4 2049.IP "ev_set_cb (ev, cb)" 4
1780.IX Item "ev_set_cb(ev,cb)" 2050.IX Item "ev_set_cb (ev, cb)"
1781.PD 2051.PD
1782Can be used to change the callback member declaration in each watcher, 2052Can be used to change the callback member declaration in each watcher,
1783and the way callbacks are invoked and set. Must expand to a struct member 2053and the way callbacks are invoked and set. Must expand to a struct member
1784definition and a statement, respectively. See the \fIev.v\fR header file for 2054definition and a statement, respectively. See the \fIev.v\fR header file for
1785their default definitions. One possible use for overriding these is to 2055their default definitions. One possible use for overriding these is to
1786avoid the ev_loop pointer as first argument in all cases, or to use method 2056avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use
1787calls instead of plain function calls in \*(C+. 2057method calls instead of plain function calls in \*(C+.
1788.Sh "\s-1EXAMPLES\s0" 2058.Sh "\s-1EXAMPLES\s0"
1789.IX Subsection "EXAMPLES" 2059.IX Subsection "EXAMPLES"
1790For a real-world example of a program the includes libev 2060For a real-world example of a program the includes libev
1791verbatim, you can have a look at the \s-1EV\s0 perl module 2061verbatim, you can have a look at the \s-1EV\s0 perl module
1792(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in 2062(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
… …
1797.Sp 2067.Sp
1798The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file 2068The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
1799that everybody includes and which overrides some autoconf choices: 2069that everybody includes and which overrides some autoconf choices:
1800.Sp 2070.Sp
1801.Vb 4 2071.Vb 4
1802\& #define EV_USE_POLL 0 2072\& #define EV_USE_POLL 0
1803\& #define EV_MULTIPLICITY 0 2073\& #define EV_MULTIPLICITY 0
1804\& #define EV_PERIODICS 0 2074\& #define EV_PERIODICS 0
1805\& #define EV_CONFIG_H <config.h> 2075\& #define EV_CONFIG_H <config.h>
1806.Ve 2076.Ve
1807.Sp 2077.Sp
1808.Vb 1 2078.Vb 1
1809\& #include "ev++.h" 2079\& #include "ev++.h"
1810.Ve 2080.Ve
1811.Sp 2081.Sp
1812And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: 2082And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
1813.Sp 2083.Sp
1814.Vb 1
1815\& #include "rxvttoolkit.h"
1816.Ve
1817.Sp
1818.Vb 2 2084.Vb 2
1819\& /* darwin has problems with its header files in C++, requiring this namespace juggling */ 2085\& #include "ev_cpp.h"
1820\& using namespace ev;
1821.Ve
1822.Sp
1823.Vb 1
1824\& #include "ev.c" 2086\& #include "ev.c"
1825.Ve 2087.Ve
2088.SH "COMPLEXITIES"
2089.IX Header "COMPLEXITIES"
2090In this section the complexities of (many of) the algorithms used inside
2091libev will be explained. For complexity discussions about backends see the
2092documentation for \f(CW\*(C`ev_default_init\*(C'\fR.
2093.RS 4
2094.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
2095.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
2096.PD 0
2097.IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4
2098.IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)"
2099.IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4
2100.IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)"
2101.IP "Stopping check/prepare/idle watchers: O(1)" 4
2102.IX Item "Stopping check/prepare/idle watchers: O(1)"
2103.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4
2104.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))"
2105.IP "Finding the next timer per loop iteration: O(1)" 4
2106.IX Item "Finding the next timer per loop iteration: O(1)"
2107.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
2108.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
2109.IP "Activating one watcher: O(1)" 4
2110.IX Item "Activating one watcher: O(1)"
2111.RE
2112.RS 4
2113.PD
1826.SH "AUTHOR" 2114.SH "AUTHOR"
1827.IX Header "AUTHOR" 2115.IX Header "AUTHOR"
1828Marc Lehmann <libev@schmorp.de>. 2116Marc Lehmann <libev@schmorp.de>.

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