… | |
… | |
115 | The interface itself is vaguely similar, but not identical to the Event |
115 | The interface itself is vaguely similar, but not identical to the Event |
116 | module. |
116 | module. |
117 | |
117 | |
118 | During the first call of any watcher-creation method, the module tries |
118 | During the first call of any watcher-creation method, the module tries |
119 | to detect the currently loaded event loop by probing whether one of the |
119 | to detect the currently loaded event loop by probing whether one of the |
120 | following modules is already loaded: EV, AnyEvent::Impl::Perl, Event, |
120 | following modules is already loaded: EV, AnyEvent::Loop, Event, Glib, |
121 | Glib, Tk, Event::Lib, Qt, POE. The first one found is used. If none are |
121 | Tk, Event::Lib, Qt, POE. The first one found is used. If none are |
122 | detected, the module tries to load the first four modules in the order |
122 | detected, the module tries to load the first four modules in the order |
123 | given; but note that if EV is not available, the pure-perl |
123 | given; but note that if EV is not available, the pure-perl |
124 | AnyEvent::Impl::Perl should always work, so the other two are not |
124 | AnyEvent::Loop should always work, so the other two are not normally |
125 | normally tried. |
125 | tried. |
126 | |
126 | |
127 | Because AnyEvent first checks for modules that are already loaded, |
127 | Because AnyEvent first checks for modules that are already loaded, |
128 | loading an event model explicitly before first using AnyEvent will |
128 | loading an event model explicitly before first using AnyEvent will |
129 | likely make that model the default. For example: |
129 | likely make that model the default. For example: |
130 | |
130 | |
… | |
… | |
136 | The *likely* means that, if any module loads another event model and |
136 | The *likely* means that, if any module loads another event model and |
137 | starts using it, all bets are off - this case should be very rare |
137 | starts using it, all bets are off - this case should be very rare |
138 | though, as very few modules hardcode event loops without announcing this |
138 | though, as very few modules hardcode event loops without announcing this |
139 | very loudly. |
139 | very loudly. |
140 | |
140 | |
141 | The pure-perl implementation of AnyEvent is called |
141 | The pure-perl implementation of AnyEvent is called "AnyEvent::Loop". |
142 | "AnyEvent::Impl::Perl". Like other event modules you can load it |
142 | Like other event modules you can load it explicitly and enjoy the high |
143 | explicitly and enjoy the high availability of that event loop :) |
143 | availability of that event loop :) |
144 | |
144 | |
145 | WATCHERS |
145 | WATCHERS |
146 | AnyEvent has the central concept of a *watcher*, which is an object that |
146 | AnyEvent has the central concept of a *watcher*, which is an object that |
147 | stores relevant data for each kind of event you are waiting for, such as |
147 | stores relevant data for each kind of event you are waiting for, such as |
148 | the callback to call, the file handle to watch, etc. |
148 | the callback to call, the file handle to watch, etc. |
… | |
… | |
347 | can get whatever behaviour you want with any event loop, by taking |
347 | can get whatever behaviour you want with any event loop, by taking |
348 | the difference between "AnyEvent->time" and "AnyEvent->now" into |
348 | the difference between "AnyEvent->time" and "AnyEvent->now" into |
349 | account. |
349 | account. |
350 | |
350 | |
351 | AnyEvent->now_update |
351 | AnyEvent->now_update |
352 | Some event loops (such as EV or AnyEvent::Impl::Perl) cache the |
352 | Some event loops (such as EV or AnyEvent::Loop) cache the current |
353 | current time for each loop iteration (see the discussion of |
353 | time for each loop iteration (see the discussion of AnyEvent->now, |
354 | AnyEvent->now, above). |
354 | above). |
355 | |
355 | |
356 | When a callback runs for a long time (or when the process sleeps), |
356 | When a callback runs for a long time (or when the process sleeps), |
357 | then this "current" time will differ substantially from the real |
357 | then this "current" time will differ substantially from the real |
358 | time, which might affect timers and time-outs. |
358 | time, which might affect timers and time-outs. |
359 | |
359 | |
… | |
… | |
466 | This means you cannot create a child watcher as the very first thing in |
466 | This means you cannot create a child watcher as the very first thing in |
467 | an AnyEvent program, you *have* to create at least one watcher before |
467 | an AnyEvent program, you *have* to create at least one watcher before |
468 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
468 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
469 | |
469 | |
470 | As most event loops do not support waiting for child events, they will |
470 | As most event loops do not support waiting for child events, they will |
471 | be emulated by AnyEvent in most cases, in which the latency and race |
471 | be emulated by AnyEvent in most cases, in which case the latency and |
472 | problems mentioned in the description of signal watchers apply. |
472 | race problems mentioned in the description of signal watchers apply. |
473 | |
473 | |
474 | Example: fork a process and wait for it |
474 | Example: fork a process and wait for it |
475 | |
475 | |
476 | my $done = AnyEvent->condvar; |
476 | my $done = AnyEvent->condvar; |
477 | |
477 | |
… | |
… | |
821 | use. If EV is not installed, then AnyEvent will fall back to its own |
821 | use. If EV is not installed, then AnyEvent will fall back to its own |
822 | pure-perl implementation, which is available everywhere as it comes |
822 | pure-perl implementation, which is available everywhere as it comes |
823 | with AnyEvent itself. |
823 | with AnyEvent itself. |
824 | |
824 | |
825 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
825 | AnyEvent::Impl::EV based on EV (interface to libev, best choice). |
826 | AnyEvent::Impl::Perl pure-perl implementation, fast and portable. |
826 | AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable. |
827 | |
827 | |
828 | Backends that are transparently being picked up when they are used. |
828 | Backends that are transparently being picked up when they are used. |
829 | These will be used if they are already loaded when the first watcher |
829 | These will be used if they are already loaded when the first watcher |
830 | is created, in which case it is assumed that the application is |
830 | is created, in which case it is assumed that the application is |
831 | using them. This means that AnyEvent will automatically pick the |
831 | using them. This means that AnyEvent will automatically pick the |
… | |
… | |
839 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
839 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
840 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
840 | AnyEvent::Impl::POE based on POE, very slow, some limitations. |
841 | AnyEvent::Impl::Irssi used when running within irssi. |
841 | AnyEvent::Impl::Irssi used when running within irssi. |
842 | AnyEvent::Impl::IOAsync based on IO::Async. |
842 | AnyEvent::Impl::IOAsync based on IO::Async. |
843 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
843 | AnyEvent::Impl::Cocoa based on Cocoa::EventLoop. |
|
|
844 | AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding). |
844 | |
845 | |
845 | Backends with special needs. |
846 | Backends with special needs. |
846 | Qt requires the Qt::Application to be instantiated first, but will |
847 | Qt requires the Qt::Application to be instantiated first, but will |
847 | otherwise be picked up automatically. As long as the main program |
848 | otherwise be picked up automatically. As long as the main program |
848 | instantiates the application before any AnyEvent watchers are |
849 | instantiates the application before any AnyEvent watchers are |
… | |
… | |
885 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
886 | Returns $AnyEvent::MODEL, forcing autodetection of the event model |
886 | if necessary. You should only call this function right before you |
887 | if necessary. You should only call this function right before you |
887 | would have created an AnyEvent watcher anyway, that is, as late as |
888 | would have created an AnyEvent watcher anyway, that is, as late as |
888 | possible at runtime, and not e.g. during initialisation of your |
889 | possible at runtime, and not e.g. during initialisation of your |
889 | module. |
890 | module. |
|
|
891 | |
|
|
892 | The effect of calling this function is as if a watcher had been |
|
|
893 | created (specifically, actions that happen "when the first watcher |
|
|
894 | is created" happen when calling detetc as well). |
890 | |
895 | |
891 | If you need to do some initialisation before AnyEvent watchers are |
896 | If you need to do some initialisation before AnyEvent watchers are |
892 | created, use "post_detect". |
897 | created, use "post_detect". |
893 | |
898 | |
894 | $guard = AnyEvent::post_detect { BLOCK } |
899 | $guard = AnyEvent::post_detect { BLOCK } |
… | |
… | |
956 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
961 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
957 | # as soon as it is |
962 | # as soon as it is |
958 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
963 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
959 | } |
964 | } |
960 | |
965 | |
|
|
966 | AnyEvent::postpone { BLOCK } |
|
|
967 | Arranges for the block to be executed as soon as possible, but not |
|
|
968 | before the call itself returns. In practise, the block will be |
|
|
969 | executed just before the event loop polls for new events, or shortly |
|
|
970 | afterwards. |
|
|
971 | |
|
|
972 | This function never returns anything (to make the "return postpone { |
|
|
973 | ... }" idiom more useful. |
|
|
974 | |
|
|
975 | To understand the usefulness of this function, consider a function |
|
|
976 | that asynchronously does something for you and returns some |
|
|
977 | transaction object or guard to let you cancel the operation. For |
|
|
978 | example, "AnyEvent::Socket::tcp_connect": |
|
|
979 | |
|
|
980 | # start a conenction attempt unless one is active |
|
|
981 | $self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub { |
|
|
982 | delete $self->{connect_guard}; |
|
|
983 | ... |
|
|
984 | }; |
|
|
985 | |
|
|
986 | Imagine that this function could instantly call the callback, for |
|
|
987 | example, because it detects an obvious error such as a negative port |
|
|
988 | number. Invoking the callback before the function returns causes |
|
|
989 | problems however: the callback will be called and will try to delete |
|
|
990 | the guard object. But since the function hasn't returned yet, there |
|
|
991 | is nothing to delete. When the function eventually returns it will |
|
|
992 | assign the guard object to "$self->{connect_guard}", where it will |
|
|
993 | likely never be deleted, so the program thinks it is still trying to |
|
|
994 | connect. |
|
|
995 | |
|
|
996 | This is where "AnyEvent::postpone" should be used. Instead of |
|
|
997 | calling the callback directly on error: |
|
|
998 | |
|
|
999 | $cb->(undef), return # signal error to callback, BAD! |
|
|
1000 | if $some_error_condition; |
|
|
1001 | |
|
|
1002 | It should use "postpone": |
|
|
1003 | |
|
|
1004 | AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later |
|
|
1005 | if $some_error_condition; |
|
|
1006 | |
961 | WHAT TO DO IN A MODULE |
1007 | WHAT TO DO IN A MODULE |
962 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
1008 | As a module author, you should "use AnyEvent" and call AnyEvent methods |
963 | freely, but you should not load a specific event module or rely on it. |
1009 | freely, but you should not load a specific event module or rely on it. |
964 | |
1010 | |
965 | Be careful when you create watchers in the module body - AnyEvent will |
1011 | Be careful when you create watchers in the module body - AnyEvent will |
… | |
… | |
995 | will decide on the event model to use as soon as it creates watchers, |
1041 | will decide on the event model to use as soon as it creates watchers, |
996 | and it might choose the wrong one unless you load the correct one |
1042 | and it might choose the wrong one unless you load the correct one |
997 | yourself. |
1043 | yourself. |
998 | |
1044 | |
999 | You can chose to use a pure-perl implementation by loading the |
1045 | You can chose to use a pure-perl implementation by loading the |
1000 | "AnyEvent::Impl::Perl" module, which gives you similar behaviour |
1046 | "AnyEvent::Loop" module, which gives you similar behaviour everywhere, |
1001 | everywhere, but letting AnyEvent chose the model is generally better. |
1047 | but letting AnyEvent chose the model is generally better. |
1002 | |
1048 | |
1003 | MAINLOOP EMULATION |
1049 | MAINLOOP EMULATION |
1004 | Sometimes (often for short test scripts, or even standalone programs who |
1050 | Sometimes (often for short test scripts, or even standalone programs who |
1005 | only want to use AnyEvent), you do not want to run a specific event |
1051 | only want to use AnyEvent), you do not want to run a specific event |
1006 | loop. |
1052 | loop. |
… | |
… | |
1141 | Unlike "use strict" (or its modern cousin, "use common::sense", it |
1187 | Unlike "use strict" (or its modern cousin, "use common::sense", it |
1142 | is definitely recommended to keep it off in production. Keeping |
1188 | is definitely recommended to keep it off in production. Keeping |
1143 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1189 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1144 | programs can be very useful, however. |
1190 | programs can be very useful, however. |
1145 | |
1191 | |
|
|
1192 | "PERL_ANYEVENT_DEBUG_SHELL" |
|
|
1193 | If this env variable is set, then its contents will be interpreted |
|
|
1194 | by "AnyEvent::Socket::parse_hostport" (after replacing every |
|
|
1195 | occurance of $$ by the process pid) and an "AnyEvent::Debug::shell" |
|
|
1196 | is bound on that port. The shell object is saved in |
|
|
1197 | $AnyEvent::Debug::SHELL. |
|
|
1198 | |
|
|
1199 | This takes place when the first watcher is created. |
|
|
1200 | |
|
|
1201 | For example, to bind a debug shell on a unix domain socket in |
|
|
1202 | /tmp/debug<pid>.sock, you could use this: |
|
|
1203 | |
|
|
1204 | PERL_ANYEVENT_DEBUG_SHELL=unix/:/tmp/debug\$\$.sock perlprog |
|
|
1205 | |
|
|
1206 | Note that creating sockets in /tmp is very unsafe on multiuser |
|
|
1207 | systems. |
|
|
1208 | |
|
|
1209 | "PERL_ANYEVENT_DEBUG_WRAP" |
|
|
1210 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
|
|
1211 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
|
|
1212 | |
1146 | "PERL_ANYEVENT_MODEL" |
1213 | "PERL_ANYEVENT_MODEL" |
1147 | This can be used to specify the event model to be used by AnyEvent, |
1214 | This can be used to specify the event model to be used by AnyEvent, |
1148 | before auto detection and -probing kicks in. It must be a string |
1215 | before auto detection and -probing kicks in. |
1149 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
1216 | |
1150 | gets prepended and the resulting module name is loaded and if the |
1217 | It normally is a string consisting entirely of ASCII letters (e.g. |
1151 | load was successful, used as event model. If it fails to load |
1218 | "EV" or "IOAsync"). The string "AnyEvent::Impl::" gets prepended and |
|
|
1219 | the resulting module name is loaded and - if the load was successful |
|
|
1220 | - used as event model backend. If it fails to load then AnyEvent |
1152 | AnyEvent will proceed with auto detection and -probing. |
1221 | will proceed with auto detection and -probing. |
1153 | |
1222 | |
1154 | This functionality might change in future versions. |
1223 | If the string ends with "::" instead (e.g. "AnyEvent::Impl::EV::") |
|
|
1224 | then nothing gets prepended and the module name is used as-is (hint: |
|
|
1225 | "::" at the end of a string designates a module name and quotes it |
|
|
1226 | appropriately). |
1155 | |
1227 | |
1156 | For example, to force the pure perl model (AnyEvent::Impl::Perl) you |
1228 | For example, to force the pure perl model (AnyEvent::Loop::Perl) you |
1157 | could start your program like this: |
1229 | could start your program like this: |
1158 | |
1230 | |
1159 | PERL_ANYEVENT_MODEL=Perl perl ... |
1231 | PERL_ANYEVENT_MODEL=Perl perl ... |
1160 | |
1232 | |
1161 | "PERL_ANYEVENT_PROTOCOLS" |
1233 | "PERL_ANYEVENT_PROTOCOLS" |
… | |
… | |
1804 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
1876 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
1805 | |
1877 | |
1806 | Time::HiRes |
1878 | Time::HiRes |
1807 | This module is part of perl since release 5.008. It will be used |
1879 | This module is part of perl since release 5.008. It will be used |
1808 | when the chosen event library does not come with a timing source of |
1880 | when the chosen event library does not come with a timing source of |
1809 | its own. The pure-perl event loop (AnyEvent::Impl::Perl) will |
1881 | its own. The pure-perl event loop (AnyEvent::Loop) will additionally |
1810 | additionally use it to try to use a monotonic clock for timing |
1882 | load it to try to use a monotonic clock for timing stability. |
1811 | stability. |
|
|
1812 | |
1883 | |
1813 | FORK |
1884 | FORK |
1814 | Most event libraries are not fork-safe. The ones who are usually are |
1885 | Most event libraries are not fork-safe. The ones who are usually are |
1815 | because they rely on inefficient but fork-safe "select" or "poll" calls |
1886 | because they rely on inefficient but fork-safe "select" or "poll" calls |
1816 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
1887 | - higher performance APIs such as BSD's kqueue or the dreaded Linux |
… | |
… | |
1873 | |
1944 | |
1874 | FAQ: AnyEvent::FAQ. |
1945 | FAQ: AnyEvent::FAQ. |
1875 | |
1946 | |
1876 | Utility functions: AnyEvent::Util. |
1947 | Utility functions: AnyEvent::Util. |
1877 | |
1948 | |
1878 | Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk, |
1949 | Event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event, |
1879 | Event::Lib, Qt, POE. |
1950 | Glib::Event, Glib, Tk, Event::Lib, Qt, POE. |
1880 | |
1951 | |
1881 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1952 | Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event, |
1882 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1953 | AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl, |
1883 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
1954 | AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE, |
1884 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. |
1955 | AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi. |