… | |
… | |
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 "2007-12-08" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- 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 |
… | |
… | |
196 | \& return 0; |
196 | \& return 0; |
197 | \& } |
197 | \& } |
198 | .Ve |
198 | .Ve |
199 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
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|
201 | The newest version of this document is also available as a html-formatted |
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202 | web page you might find easier to navigate when reading it for the first |
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203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
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|
204 | .PP |
201 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
202 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occuring), and it will manage |
203 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
204 | .PP |
208 | .PP |
205 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
… | |
… | |
411 | or setgid) then libev will \fInot\fR look at the environment variable |
415 | or 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 |
416 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
413 | override the flags completely if it is found in the environment. This is |
417 | override the flags completely if it is found in the environment. This is |
414 | useful to try out specific backends to test their performance, or to work |
418 | useful to try out specific backends to test their performance, or to work |
415 | around bugs. |
419 | around bugs. |
|
|
420 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
|
|
421 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
|
|
422 | .IX Item "EVFLAG_FORKCHECK" |
|
|
423 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
|
|
424 | a fork, you can also make libev check for a fork in each iteration by |
|
|
425 | enabling this flag. |
|
|
426 | .Sp |
|
|
427 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
|
|
428 | and thus this might slow down your event loop if you do a lot of loop |
|
|
429 | iterations and little real work, but is usually not noticeable (on my |
|
|
430 | Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
|
|
431 | without a syscall and thus \fIvery\fR fast, but my Linux system also has |
|
|
432 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
|
|
433 | .Sp |
|
|
434 | The big advantage of this flag is that you can forget about fork (and |
|
|
435 | forget about forgetting to tell libev about forking) when you use this |
|
|
436 | flag. |
|
|
437 | .Sp |
|
|
438 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
|
|
439 | environment variable. |
416 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
440 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
417 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
441 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
418 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
442 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
419 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
443 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
420 | libev tries to roll its own fd_set with no limits on the number of fds, |
444 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
561 | .IP "ev_loop_fork (loop)" 4 |
585 | .IP "ev_loop_fork (loop)" 4 |
562 | .IX Item "ev_loop_fork (loop)" |
586 | .IX Item "ev_loop_fork (loop)" |
563 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
587 | Like \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 |
588 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
565 | after fork, and how you do this is entirely your own problem. |
589 | after fork, and how you do this is entirely your own problem. |
|
|
590 | .IP "unsigned int ev_loop_count (loop)" 4 |
|
|
591 | .IX Item "unsigned int ev_loop_count (loop)" |
|
|
592 | Returns the count of loop iterations for the loop, which is identical to |
|
|
593 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
|
|
594 | happily wraps around with enough iterations. |
|
|
595 | .Sp |
|
|
596 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
597 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
|
|
598 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
566 | .IP "unsigned int ev_backend (loop)" 4 |
599 | .IP "unsigned int ev_backend (loop)" 4 |
567 | .IX Item "unsigned int ev_backend (loop)" |
600 | .IX Item "unsigned int ev_backend (loop)" |
568 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
601 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
569 | use. |
602 | use. |
570 | .IP "ev_tstamp ev_now (loop)" 4 |
603 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
856 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
889 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
857 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
890 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
858 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
891 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
859 | events but its callback has not yet been invoked). As long as a watcher |
892 | events but its callback has not yet been invoked). As long as a watcher |
860 | is pending (but not active) you must not call an init function on it (but |
893 | is pending (but not active) you must not call an init function on it (but |
861 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to |
894 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must |
862 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
895 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
896 | it). |
863 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
897 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
864 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
898 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
865 | Returns the callback currently set on the watcher. |
899 | Returns the callback currently set on the watcher. |
866 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
900 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
867 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
901 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
868 | Change the callback. You can change the callback at virtually any time |
902 | Change the callback. You can change the callback at virtually any time |
869 | (modulo threads). |
903 | (modulo threads). |
|
|
904 | .IP "ev_set_priority (ev_TYPE *watcher, priority)" 4 |
|
|
905 | .IX Item "ev_set_priority (ev_TYPE *watcher, priority)" |
|
|
906 | .PD 0 |
|
|
907 | .IP "int ev_priority (ev_TYPE *watcher)" 4 |
|
|
908 | .IX Item "int ev_priority (ev_TYPE *watcher)" |
|
|
909 | .PD |
|
|
910 | Set and query the priority of the watcher. The priority is a small |
|
|
911 | integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR |
|
|
912 | (default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked |
|
|
913 | before watchers with lower priority, but priority will not keep watchers |
|
|
914 | from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers). |
|
|
915 | .Sp |
|
|
916 | This means that priorities are \fIonly\fR used for ordering callback |
|
|
917 | invocation after new events have been received. This is useful, for |
|
|
918 | example, to reduce latency after idling, or more often, to bind two |
|
|
919 | watchers on the same event and make sure one is called first. |
|
|
920 | .Sp |
|
|
921 | If you need to suppress invocation when higher priority events are pending |
|
|
922 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
|
|
923 | .Sp |
|
|
924 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
925 | pending. |
|
|
926 | .Sp |
|
|
927 | The default priority used by watchers when no priority has been set is |
|
|
928 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
|
|
929 | .Sp |
|
|
930 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
|
|
931 | fine, as long as you do not mind that the priority value you query might |
|
|
932 | or might not have been adjusted to be within valid range. |
|
|
933 | .IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 |
|
|
934 | .IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" |
|
|
935 | Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither |
|
|
936 | \&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback |
|
|
937 | can deal with that fact. |
|
|
938 | .IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4 |
|
|
939 | .IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)" |
|
|
940 | If the watcher is pending, this function returns clears its pending status |
|
|
941 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
942 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
870 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
943 | .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" |
944 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
872 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
945 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
873 | and read at any time, libev will completely ignore it. This can be used |
946 | and read at any time, libev will completely ignore it. This can be used |
874 | to associate arbitrary data with your watcher. If you need more data and |
947 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
985 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1058 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
986 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1059 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
987 | .PP |
1060 | .PP |
988 | If you cannot run the fd in non-blocking mode (for example you should not |
1061 | If you cannot run the fd in non-blocking mode (for example you should not |
989 | play around with an Xlib connection), then you have to seperately re-test |
1062 | play around with an Xlib connection), then you have to seperately re-test |
990 | wether a file descriptor is really ready with a known-to-be good interface |
1063 | whether a file descriptor is really ready with a known-to-be good interface |
991 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1064 | such as poll (fortunately in our Xlib example, Xlib already does this on |
992 | its own, so its quite safe to use). |
1065 | its own, so its quite safe to use). |
993 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1066 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
994 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1067 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
995 | .PD 0 |
1068 | .PD 0 |
… | |
… | |
1479 | \& ev_stat_start (loop, &passwd); |
1552 | \& ev_stat_start (loop, &passwd); |
1480 | .Ve |
1553 | .Ve |
1481 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1554 | .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..." |
1555 | .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..." |
1556 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1484 | Idle watchers trigger events when there are no other events are pending |
1557 | Idle 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 |
1558 | priority are pending (prepare, check and other idle watchers do not |
1486 | as your process is busy handling sockets or timeouts (or even signals, |
1559 | count). |
1487 | imagine) it will not be triggered. But when your process is idle all idle |
1560 | .PP |
1488 | watchers are being called again and again, once per event loop iteration \- |
1561 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1562 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1563 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1564 | are pending), the idle watchers are being called once per event loop |
1489 | until stopped, that is, or your process receives more events and becomes |
1565 | iteration \- until stopped, that is, or your process receives more events |
1490 | busy. |
1566 | and becomes busy again with higher priority stuff. |
1491 | .PP |
1567 | .PP |
1492 | The most noteworthy effect is that as long as any idle watchers are |
1568 | The most noteworthy effect is that as long as any idle watchers are |
1493 | active, the process will not block when waiting for new events. |
1569 | active, the process will not block when waiting for new events. |
1494 | .PP |
1570 | .PP |
1495 | Apart from keeping your process non-blocking (which is a useful |
1571 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
1590 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1666 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
1591 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1667 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
1592 | \& } |
1668 | \& } |
1593 | .Ve |
1669 | .Ve |
1594 | .PP |
1670 | .PP |
1595 | .Vb 7 |
1671 | .Vb 8 |
1596 | \& // create io watchers for each fd and a timer before blocking |
1672 | \& // create io watchers for each fd and a timer before blocking |
1597 | \& static void |
1673 | \& static void |
1598 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1674 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1599 | \& { |
1675 | \& { |
1600 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
1676 | \& int timeout = 3600000; |
|
|
1677 | \& struct pollfd fds [nfd]; |
1601 | \& // actual code will need to loop here and realloc etc. |
1678 | \& // actual code will need to loop here and realloc etc. |
1602 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1679 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1603 | .Ve |
1680 | .Ve |
1604 | .PP |
1681 | .PP |
1605 | .Vb 3 |
1682 | .Vb 3 |
… | |
… | |
1831 | .PP |
1908 | .PP |
1832 | .Vb 1 |
1909 | .Vb 1 |
1833 | \& #include <ev++.h> |
1910 | \& #include <ev++.h> |
1834 | .Ve |
1911 | .Ve |
1835 | .PP |
1912 | .PP |
1836 | (it is not installed by default). This automatically includes \fIev.h\fR |
1913 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1837 | and puts all of its definitions (many of them macros) into the global |
1914 | of them macros) into the global namespace. All \*(C+ specific things are |
1838 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
1915 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
1916 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1839 | .PP |
1917 | .PP |
1840 | It should support all the same embedding options as \fIev.h\fR, most notably |
1918 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1841 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1919 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
1920 | that the watcher is associated with (or no additional members at all if |
|
|
1921 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
1922 | .PP |
|
|
1923 | Currently, functions, and static and non-static member functions can be |
|
|
1924 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1925 | need one additional pointer for context. If you need support for other |
|
|
1926 | types of functors please contact the author (preferably after implementing |
|
|
1927 | it). |
1842 | .PP |
1928 | .PP |
1843 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1929 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1844 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1930 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1845 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1931 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1846 | .IX Item "ev::READ, ev::WRITE etc." |
1932 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1858 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1944 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1859 | defines by many implementations. |
1945 | defines by many implementations. |
1860 | .Sp |
1946 | .Sp |
1861 | All of those classes have these methods: |
1947 | All of those classes have these methods: |
1862 | .RS 4 |
1948 | .RS 4 |
1863 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
1949 | .IP "ev::TYPE::TYPE ()" 4 |
1864 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
1950 | .IX Item "ev::TYPE::TYPE ()" |
1865 | .PD 0 |
1951 | .PD 0 |
1866 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
1952 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1867 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
1953 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1868 | .IP "ev::TYPE::~TYPE" 4 |
1954 | .IP "ev::TYPE::~TYPE" 4 |
1869 | .IX Item "ev::TYPE::~TYPE" |
1955 | .IX Item "ev::TYPE::~TYPE" |
1870 | .PD |
1956 | .PD |
1871 | The constructor takes a pointer to an object and a method pointer to |
1957 | The constructor (optionally) takes an event loop to associate the watcher |
1872 | the event handler callback to call in this class. The constructor calls |
1958 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1873 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
1959 | .Sp |
1874 | before starting it. If you do not specify a loop then the constructor |
1960 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1875 | automatically associates the default loop with this watcher. |
1961 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
1962 | .Sp |
|
|
1963 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
1964 | method to set a callback before you can start the watcher. |
|
|
1965 | .Sp |
|
|
1966 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
1967 | not allow explicit template arguments for constructors). |
1876 | .Sp |
1968 | .Sp |
1877 | The destructor automatically stops the watcher if it is active. |
1969 | The destructor automatically stops the watcher if it is active. |
|
|
1970 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
1971 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
1972 | This method sets the callback method to call. The method has to have a |
|
|
1973 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
1974 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
1975 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
1976 | .Sp |
|
|
1977 | This method synthesizes efficient thunking code to call your method from |
|
|
1978 | the C callback that libev requires. If your compiler can inline your |
|
|
1979 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
1980 | your compiler is good :), then the method will be fully inlined into the |
|
|
1981 | thunking function, making it as fast as a direct C callback. |
|
|
1982 | .Sp |
|
|
1983 | Example: simple class declaration and watcher initialisation |
|
|
1984 | .Sp |
|
|
1985 | .Vb 4 |
|
|
1986 | \& struct myclass |
|
|
1987 | \& { |
|
|
1988 | \& void io_cb (ev::io &w, int revents) { } |
|
|
1989 | \& } |
|
|
1990 | .Ve |
|
|
1991 | .Sp |
|
|
1992 | .Vb 3 |
|
|
1993 | \& myclass obj; |
|
|
1994 | \& ev::io iow; |
|
|
1995 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1996 | .Ve |
|
|
1997 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
1998 | .IX Item "w->set<function> (void *data = 0)" |
|
|
1999 | Also sets a callback, but uses a static method or plain function as |
|
|
2000 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2001 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2002 | .Sp |
|
|
2003 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2004 | .Sp |
|
|
2005 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2006 | .Sp |
|
|
2007 | Example: |
|
|
2008 | .Sp |
|
|
2009 | .Vb 2 |
|
|
2010 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2011 | \& iow.set <io_cb> (); |
|
|
2012 | .Ve |
1878 | .IP "w\->set (struct ev_loop *)" 4 |
2013 | .IP "w\->set (struct ev_loop *)" 4 |
1879 | .IX Item "w->set (struct ev_loop *)" |
2014 | .IX Item "w->set (struct ev_loop *)" |
1880 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2015 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1881 | do this when the watcher is inactive (and not pending either). |
2016 | do this when the watcher is inactive (and not pending either). |
1882 | .IP "w\->set ([args])" 4 |
2017 | .IP "w\->set ([args])" 4 |
1883 | .IX Item "w->set ([args])" |
2018 | .IX Item "w->set ([args])" |
1884 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2019 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1885 | called at least once. Unlike the C counterpart, an active watcher gets |
2020 | called at least once. Unlike the C counterpart, an active watcher gets |
1886 | automatically stopped and restarted. |
2021 | automatically stopped and restarted when reconfiguring it with this |
|
|
2022 | method. |
1887 | .IP "w\->start ()" 4 |
2023 | .IP "w\->start ()" 4 |
1888 | .IX Item "w->start ()" |
2024 | .IX Item "w->start ()" |
1889 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2025 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1890 | constructor already takes the loop. |
2026 | constructor already stores the event loop. |
1891 | .IP "w\->stop ()" 4 |
2027 | .IP "w\->stop ()" 4 |
1892 | .IX Item "w->stop ()" |
2028 | .IX Item "w->stop ()" |
1893 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2029 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1894 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2030 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1895 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2031 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1921 | .Vb 2 |
2057 | .Vb 2 |
1922 | \& myclass (); |
2058 | \& myclass (); |
1923 | \& } |
2059 | \& } |
1924 | .Ve |
2060 | .Ve |
1925 | .PP |
2061 | .PP |
1926 | .Vb 6 |
2062 | .Vb 4 |
1927 | \& myclass::myclass (int fd) |
2063 | \& myclass::myclass (int fd) |
1928 | \& : io (this, &myclass::io_cb), |
|
|
1929 | \& idle (this, &myclass::idle_cb) |
|
|
1930 | \& { |
2064 | \& { |
|
|
2065 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2066 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2067 | .Ve |
|
|
2068 | .PP |
|
|
2069 | .Vb 2 |
1931 | \& io.start (fd, ev::READ); |
2070 | \& io.start (fd, ev::READ); |
1932 | \& } |
2071 | \& } |
1933 | .Ve |
2072 | .Ve |
1934 | .SH "MACRO MAGIC" |
2073 | .SH "MACRO MAGIC" |
1935 | .IX Header "MACRO MAGIC" |
2074 | .IX Header "MACRO MAGIC" |
1936 | Libev can be compiled with a variety of options, the most fundemantal is |
2075 | Libev can be compiled with a variety of options, the most fundemantal is |
1937 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
2076 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
1938 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2077 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1939 | .PP |
2078 | .PP |
1940 | To make it easier to write programs that cope with either variant, the |
2079 | To make it easier to write programs that cope with either variant, the |
1941 | following macros are defined: |
2080 | following macros are defined: |
1942 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2081 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
… | |
… | |
1977 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
2116 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
1978 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2117 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
1979 | Similar to the other two macros, this gives you the value of the default |
2118 | Similar to the other two macros, this gives you the value of the default |
1980 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2119 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
1981 | .PP |
2120 | .PP |
1982 | Example: Declare and initialise a check watcher, working regardless of |
2121 | Example: Declare and initialise a check watcher, utilising the above |
1983 | wether multiple loops are supported or not. |
2122 | macros so it will work regardless of whether multiple loops are supported |
|
|
2123 | or not. |
1984 | .PP |
2124 | .PP |
1985 | .Vb 5 |
2125 | .Vb 5 |
1986 | \& static void |
2126 | \& static void |
1987 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2127 | \& check_cb (EV_P_ ev_timer *w, int revents) |
1988 | \& { |
2128 | \& { |
… | |
… | |
2051 | .Vb 1 |
2191 | .Vb 1 |
2052 | \& ev_win32.c required on win32 platforms only |
2192 | \& ev_win32.c required on win32 platforms only |
2053 | .Ve |
2193 | .Ve |
2054 | .PP |
2194 | .PP |
2055 | .Vb 5 |
2195 | .Vb 5 |
2056 | \& ev_select.c only when select backend is enabled (which is by default) |
2196 | \& 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) |
2197 | \& 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) |
2198 | \& 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) |
2199 | \& 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) |
2200 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2061 | .Ve |
2201 | .Ve |
… | |
… | |
2214 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2354 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2215 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2355 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2216 | additional independent event loops. Otherwise there will be no support |
2356 | additional independent event loops. Otherwise there will be no support |
2217 | for multiple event loops and there is no first event loop pointer |
2357 | for multiple event loops and there is no first event loop pointer |
2218 | argument. Instead, all functions act on the single default loop. |
2358 | argument. Instead, all functions act on the single default loop. |
|
|
2359 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2360 | .IX Item "EV_MINPRI" |
|
|
2361 | .PD 0 |
|
|
2362 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2363 | .IX Item "EV_MAXPRI" |
|
|
2364 | .PD |
|
|
2365 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
|
|
2366 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
|
|
2367 | provide for more priorities by overriding those symbols (usually defined |
|
|
2368 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
|
|
2369 | .Sp |
|
|
2370 | When doing priority-based operations, libev usually has to linearly search |
|
|
2371 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2372 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
|
|
2373 | fine. |
|
|
2374 | .Sp |
|
|
2375 | If your embedding app does not need any priorities, defining these both to |
|
|
2376 | \&\f(CW0\fR will save some memory and cpu. |
2219 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2377 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2220 | .IX Item "EV_PERIODIC_ENABLE" |
2378 | .IX Item "EV_PERIODIC_ENABLE" |
2221 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2379 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2380 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2381 | code. |
|
|
2382 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
2383 | .IX Item "EV_IDLE_ENABLE" |
|
|
2384 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
2222 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2385 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2223 | code. |
2386 | code. |
2224 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2387 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
2225 | .IX Item "EV_EMBED_ENABLE" |
2388 | .IX Item "EV_EMBED_ENABLE" |
2226 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
2389 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
… | |
… | |
2288 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2451 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
2289 | will be compiled. It is pretty complex because it provides its own header |
2452 | will be compiled. It is pretty complex because it provides its own header |
2290 | file. |
2453 | file. |
2291 | .Sp |
2454 | .Sp |
2292 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2455 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
2293 | that everybody includes and which overrides some autoconf choices: |
2456 | that everybody includes and which overrides some configure choices: |
2294 | .Sp |
2457 | .Sp |
2295 | .Vb 4 |
2458 | .Vb 9 |
|
|
2459 | \& #define EV_MINIMAL 1 |
2296 | \& #define EV_USE_POLL 0 |
2460 | \& #define EV_USE_POLL 0 |
2297 | \& #define EV_MULTIPLICITY 0 |
2461 | \& #define EV_MULTIPLICITY 0 |
2298 | \& #define EV_PERIODICS 0 |
2462 | \& #define EV_PERIODIC_ENABLE 0 |
|
|
2463 | \& #define EV_STAT_ENABLE 0 |
|
|
2464 | \& #define EV_FORK_ENABLE 0 |
2299 | \& #define EV_CONFIG_H <config.h> |
2465 | \& #define EV_CONFIG_H <config.h> |
|
|
2466 | \& #define EV_MINPRI 0 |
|
|
2467 | \& #define EV_MAXPRI 0 |
2300 | .Ve |
2468 | .Ve |
2301 | .Sp |
2469 | .Sp |
2302 | .Vb 1 |
2470 | .Vb 1 |
2303 | \& #include "ev++.h" |
2471 | \& #include "ev++.h" |
2304 | .Ve |
2472 | .Ve |
… | |
… | |
2312 | .SH "COMPLEXITIES" |
2480 | .SH "COMPLEXITIES" |
2313 | .IX Header "COMPLEXITIES" |
2481 | .IX Header "COMPLEXITIES" |
2314 | In this section the complexities of (many of) the algorithms used inside |
2482 | In this section the complexities of (many of) the algorithms used inside |
2315 | libev will be explained. For complexity discussions about backends see the |
2483 | libev will be explained. For complexity discussions about backends see the |
2316 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2484 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
|
|
2485 | .Sp |
|
|
2486 | All of the following are about amortised time: If an array needs to be |
|
|
2487 | extended, libev needs to realloc and move the whole array, but this |
|
|
2488 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2489 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2490 | it is much faster and asymptotically approaches constant time. |
2317 | .RS 4 |
2491 | .RS 4 |
2318 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2492 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2319 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2493 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2320 | .PD 0 |
2494 | This means that, when you have a watcher that triggers in one hour and |
|
|
2495 | there are 100 watchers that would trigger before that then inserting will |
|
|
2496 | have to skip those 100 watchers. |
2321 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2497 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2322 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2498 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
|
|
2499 | That means that for changing a timer costs less than removing/adding them |
|
|
2500 | as only the relative motion in the event queue has to be paid for. |
2323 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2501 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2324 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2502 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2325 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2503 | These just add the watcher into an array or at the head of a list. |
2326 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2504 | =item Stopping check/prepare/idle watchers: O(1) |
2327 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2505 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2328 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2506 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
|
|
2507 | These watchers are stored in lists then need to be walked to find the |
|
|
2508 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2509 | have many watchers waiting for the same fd or signal). |
2329 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2510 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2330 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2511 | .IX Item "Finding the next timer per loop iteration: O(1)" |
|
|
2512 | .PD 0 |
2331 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2513 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2332 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2514 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
|
|
2515 | .PD |
|
|
2516 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2517 | libev to recalculate its status (and possibly tell the kernel). |
2333 | .IP "Activating one watcher: O(1)" 4 |
2518 | .IP "Activating one watcher: O(1)" 4 |
2334 | .IX Item "Activating one watcher: O(1)" |
2519 | .IX Item "Activating one watcher: O(1)" |
|
|
2520 | .PD 0 |
|
|
2521 | .IP "Priority handling: O(number_of_priorities)" 4 |
|
|
2522 | .IX Item "Priority handling: O(number_of_priorities)" |
|
|
2523 | .PD |
|
|
2524 | Priorities are implemented by allocating some space for each |
|
|
2525 | priority. When doing priority-based operations, libev usually has to |
|
|
2526 | linearly search all the priorities. |
2335 | .RE |
2527 | .RE |
2336 | .RS 4 |
2528 | .RS 4 |
2337 | .PD |
|
|
2338 | .SH "AUTHOR" |
2529 | .SH "AUTHOR" |
2339 | .IX Header "AUTHOR" |
2530 | .IX Header "AUTHOR" |
2340 | Marc Lehmann <libev@schmorp.de>. |
2531 | Marc Lehmann <libev@schmorp.de>. |