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Comparing libev/ev.3 (file contents):
Revision 1.34 by root, Thu Nov 29 12:21:21 2007 UTC vs.
Revision 1.37 by root, Fri Dec 7 16:49:49 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 "2007-11-29" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-12-07" "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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411or setgid) then libev will \fInot\fR look at the environment variable 411or setgid) then libev will \fInot\fR look at the environment variable
412\&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will 412\&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will
413override the flags completely if it is found in the environment. This is 413override the flags completely if it is found in the environment. This is
414useful to try out specific backends to test their performance, or to work 414useful to try out specific backends to test their performance, or to work
415around bugs. 415around bugs.
416.ie n .IP """EVFLAG_FORKCHECK""" 4
417.el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4
418.IX Item "EVFLAG_FORKCHECK"
419Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after
420a fork, you can also make libev check for a fork in each iteration by
421enabling this flag.
422.Sp
423This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop,
424and thus this might slow down your event loop if you do a lot of loop
425iterations and little real work, but is usually not noticeable (on my
426Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence
427without a syscall and thus \fIvery\fR fast, but my Linux system also has
428\&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster).
429.Sp
430The big advantage of this flag is that you can forget about fork (and
431forget about forgetting to tell libev about forking) when you use this
432flag.
433.Sp
434This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR
435environment variable.
416.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 436.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4
417.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 437.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4
418.IX Item "EVBACKEND_SELECT (value 1, portable select backend)" 438.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"
419This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as 439This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as
420libev tries to roll its own fd_set with no limits on the number of fds, 440libev tries to roll its own fd_set with no limits on the number of fds,
… …
561.IP "ev_loop_fork (loop)" 4 581.IP "ev_loop_fork (loop)" 4
562.IX Item "ev_loop_fork (loop)" 582.IX Item "ev_loop_fork (loop)"
563Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by 583Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by
564\&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop 584\&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop
565after fork, and how you do this is entirely your own problem. 585after fork, and how you do this is entirely your own problem.
586.IP "unsigned int ev_loop_count (loop)" 4
587.IX Item "unsigned int ev_loop_count (loop)"
588Returns the count of loop iterations for the loop, which is identical to
589the number of times libev did poll for new events. It starts at \f(CW0\fR and
590happily wraps around with enough iterations.
591.Sp
592This value can sometimes be useful as a generation counter of sorts (it
593\&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with
594\&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls.
566.IP "unsigned int ev_backend (loop)" 4 595.IP "unsigned int ev_backend (loop)" 4
567.IX Item "unsigned int ev_backend (loop)" 596.IX Item "unsigned int ev_backend (loop)"
568Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in 597Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in
569use. 598use.
570.IP "ev_tstamp ev_now (loop)" 4 599.IP "ev_tstamp ev_now (loop)" 4
… …
865Returns the callback currently set on the watcher. 894Returns the callback currently set on the watcher.
866.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 895.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
867.IX Item "ev_cb_set (ev_TYPE *watcher, callback)" 896.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
868Change the callback. You can change the callback at virtually any time 897Change the callback. You can change the callback at virtually any time
869(modulo threads). 898(modulo threads).
899.IP "ev_set_priority (ev_TYPE *watcher, priority)" 4
900.IX Item "ev_set_priority (ev_TYPE *watcher, priority)"
901.PD 0
902.IP "int ev_priority (ev_TYPE *watcher)" 4
903.IX Item "int ev_priority (ev_TYPE *watcher)"
904.PD
905Set and query the priority of the watcher. The priority is a small
906integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR
907(default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked
908before watchers with lower priority, but priority will not keep watchers
909from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers).
910.Sp
911This means that priorities are \fIonly\fR used for ordering callback
912invocation after new events have been received. This is useful, for
913example, to reduce latency after idling, or more often, to bind two
914watchers on the same event and make sure one is called first.
915.Sp
916If you need to suppress invocation when higher priority events are pending
917you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality.
918.Sp
919The default priority used by watchers when no priority has been set is
920always \f(CW0\fR, which is supposed to not be too high and not be too low :).
921.Sp
922Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is
923fine, as long as you do not mind that the priority value you query might
924or might not have been adjusted to be within valid range.
870.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" 925.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"
871.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" 926.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
872Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change 927Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change
873and read at any time, libev will completely ignore it. This can be used 928and read at any time, libev will completely ignore it. This can be used
874to associate arbitrary data with your watcher. If you need more data and 929to associate arbitrary data with your watcher. If you need more data and
… …
1479\& ev_stat_start (loop, &passwd); 1534\& ev_stat_start (loop, &passwd);
1480.Ve 1535.Ve
1481.ie n .Sh """ev_idle"" \- when you've got nothing better to do..." 1536.ie n .Sh """ev_idle"" \- when you've got nothing better to do..."
1482.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." 1537.el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..."
1483.IX Subsection "ev_idle - when you've got nothing better to do..." 1538.IX Subsection "ev_idle - when you've got nothing better to do..."
1484Idle watchers trigger events when there are no other events are pending 1539Idle watchers trigger events when no other events of the same or higher
1485(prepare, check and other idle watchers do not count). That is, as long 1540priority are pending (prepare, check and other idle watchers do not
1486as your process is busy handling sockets or timeouts (or even signals, 1541count).
1487imagine) it will not be triggered. But when your process is idle all idle 1542.PP
1488watchers are being called again and again, once per event loop iteration \- 1543That is, as long as your process is busy handling sockets or timeouts
1544(or even signals, imagine) of the same or higher priority it will not be
1545triggered. But when your process is idle (or only lower-priority watchers
1546are pending), the idle watchers are being called once per event loop
1489until stopped, that is, or your process receives more events and becomes 1547iteration \- until stopped, that is, or your process receives more events
1490busy. 1548and becomes busy again with higher priority stuff.
1491.PP 1549.PP
1492The most noteworthy effect is that as long as any idle watchers are 1550The most noteworthy effect is that as long as any idle watchers are
1493active, the process will not block when waiting for new events. 1551active, the process will not block when waiting for new events.
1494.PP 1552.PP
1495Apart from keeping your process non-blocking (which is a useful 1553Apart from keeping your process non-blocking (which is a useful
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1590\& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; 1648\& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1591\& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; 1649\& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
1592\& } 1650\& }
1593.Ve 1651.Ve
1594.PP 1652.PP
1595.Vb 7 1653.Vb 8
1596\& // create io watchers for each fd and a timer before blocking 1654\& // create io watchers for each fd and a timer before blocking
1597\& static void 1655\& static void
1598\& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) 1656\& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents)
1599\& { 1657\& {
1600\& int timeout = 3600000;truct pollfd fds [nfd]; 1658\& int timeout = 3600000;
1659\& struct pollfd fds [nfd];
1601\& // actual code will need to loop here and realloc etc. 1660\& // actual code will need to loop here and realloc etc.
1602\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); 1661\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
1603.Ve 1662.Ve
1604.PP 1663.PP
1605.Vb 3 1664.Vb 3
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1977.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 2036.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
1978.IX Item "EV_DEFAULT, EV_DEFAULT_" 2037.IX Item "EV_DEFAULT, EV_DEFAULT_"
1979Similar to the other two macros, this gives you the value of the default 2038Similar to the other two macros, this gives you the value of the default
1980loop, if multiple loops are supported (\*(L"ev loop default\*(R"). 2039loop, if multiple loops are supported (\*(L"ev loop default\*(R").
1981.PP 2040.PP
1982Example: Declare and initialise a check watcher, working regardless of 2041Example: Declare and initialise a check watcher, utilising the above
1983wether multiple loops are supported or not. 2042macros so it will work regardless of wether multiple loops are supported
2043or not.
1984.PP 2044.PP
1985.Vb 5 2045.Vb 5
1986\& static void 2046\& static void
1987\& check_cb (EV_P_ ev_timer *w, int revents) 2047\& check_cb (EV_P_ ev_timer *w, int revents)
1988\& { 2048\& {
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2051.Vb 1 2111.Vb 1
2052\& ev_win32.c required on win32 platforms only 2112\& ev_win32.c required on win32 platforms only
2053.Ve 2113.Ve
2054.PP 2114.PP
2055.Vb 5 2115.Vb 5
2056\& ev_select.c only when select backend is enabled (which is by default) 2116\& ev_select.c only when select backend is enabled (which is enabled by default)
2057\& ev_poll.c only when poll backend is enabled (disabled by default) 2117\& ev_poll.c only when poll backend is enabled (disabled by default)
2058\& ev_epoll.c only when the epoll backend is enabled (disabled by default) 2118\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
2059\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) 2119\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
2060\& ev_port.c only when the solaris port backend is enabled (disabled by default) 2120\& ev_port.c only when the solaris port backend is enabled (disabled by default)
2061.Ve 2121.Ve
… …
2219.IP "\s-1EV_PERIODIC_ENABLE\s0" 4 2279.IP "\s-1EV_PERIODIC_ENABLE\s0" 4
2220.IX Item "EV_PERIODIC_ENABLE" 2280.IX Item "EV_PERIODIC_ENABLE"
2221If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If 2281If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If
2222defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of 2282defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
2223code. 2283code.
2284.IP "\s-1EV_IDLE_ENABLE\s0" 4
2285.IX Item "EV_IDLE_ENABLE"
2286If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If
2287defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of
2288code.
2224.IP "\s-1EV_EMBED_ENABLE\s0" 4 2289.IP "\s-1EV_EMBED_ENABLE\s0" 4
2225.IX Item "EV_EMBED_ENABLE" 2290.IX Item "EV_EMBED_ENABLE"
2226If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If 2291If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If
2227defined to be \f(CW0\fR, then they are not. 2292defined to be \f(CW0\fR, then they are not.
2228.IP "\s-1EV_STAT_ENABLE\s0" 4 2293.IP "\s-1EV_STAT_ENABLE\s0" 4
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2288interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file 2353interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
2289will be compiled. It is pretty complex because it provides its own header 2354will be compiled. It is pretty complex because it provides its own header
2290file. 2355file.
2291.Sp 2356.Sp
2292The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file 2357The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
2293that everybody includes and which overrides some autoconf choices: 2358that everybody includes and which overrides some configure choices:
2294.Sp 2359.Sp
2295.Vb 4 2360.Vb 9
2361\& #define EV_MINIMAL 1
2296\& #define EV_USE_POLL 0 2362\& #define EV_USE_POLL 0
2297\& #define EV_MULTIPLICITY 0 2363\& #define EV_MULTIPLICITY 0
2298\& #define EV_PERIODICS 0 2364\& #define EV_PERIODIC_ENABLE 0
2365\& #define EV_STAT_ENABLE 0
2366\& #define EV_FORK_ENABLE 0
2299\& #define EV_CONFIG_H <config.h> 2367\& #define EV_CONFIG_H <config.h>
2368\& #define EV_MINPRI 0
2369\& #define EV_MAXPRI 0
2300.Ve 2370.Ve
2301.Sp 2371.Sp
2302.Vb 1 2372.Vb 1
2303\& #include "ev++.h" 2373\& #include "ev++.h"
2304.Ve 2374.Ve

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