… | |
… | |
363 | might affect timers and time-outs. |
363 | might affect timers and time-outs. |
364 | |
364 | |
365 | When this is the case, you can call this method, which will update the |
365 | When this is the case, you can call this method, which will update the |
366 | event loop's idea of "current time". |
366 | event loop's idea of "current time". |
367 | |
367 | |
|
|
368 | A typical example would be a script in a web server (e.g. C<mod_perl>) - |
|
|
369 | when mod_perl executes the script, then the event loop will have the wrong |
|
|
370 | idea about the "current time" (being potentially far in the past, when the |
|
|
371 | script ran the last time). In that case you should arrange a call to C<< |
|
|
372 | AnyEvent->now_update >> each time the web server process wakes up again |
|
|
373 | (e.g. at the start of your script, or in a handler). |
|
|
374 | |
368 | Note that updating the time I<might> cause some events to be handled. |
375 | Note that updating the time I<might> cause some events to be handled. |
369 | |
376 | |
370 | =back |
377 | =back |
371 | |
378 | |
372 | =head2 SIGNAL WATCHERS |
379 | =head2 SIGNAL WATCHERS |
… | |
… | |
395 | correctly. |
402 | correctly. |
396 | |
403 | |
397 | Example: exit on SIGINT |
404 | Example: exit on SIGINT |
398 | |
405 | |
399 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
406 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
|
|
407 | |
|
|
408 | =head3 Restart Behaviour |
|
|
409 | |
|
|
410 | While restart behaviour is up to the event loop implementation, most will |
|
|
411 | not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's |
|
|
412 | pure perl implementation). |
|
|
413 | |
|
|
414 | =head3 Safe/Unsafe Signals |
|
|
415 | |
|
|
416 | Perl signals can be either "safe" (synchronous to opcode handling) or |
|
|
417 | "unsafe" (asynchronous) - the former might get delayed indefinitely, the |
|
|
418 | latter might corrupt your memory. |
|
|
419 | |
|
|
420 | AnyEvent signal handlers are, in addition, synchronous to the event loop, |
|
|
421 | i.e. they will not interrupt your running perl program but will only be |
|
|
422 | called as part of the normal event handling (just like timer, I/O etc. |
|
|
423 | callbacks, too). |
400 | |
424 | |
401 | =head3 Signal Races, Delays and Workarounds |
425 | =head3 Signal Races, Delays and Workarounds |
402 | |
426 | |
403 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
427 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
404 | callbacks to signals in a generic way, which is a pity, as you cannot |
428 | callbacks to signals in a generic way, which is a pity, as you cannot |
… | |
… | |
479 | |
503 | |
480 | =head2 IDLE WATCHERS |
504 | =head2 IDLE WATCHERS |
481 | |
505 | |
482 | $w = AnyEvent->idle (cb => <callback>); |
506 | $w = AnyEvent->idle (cb => <callback>); |
483 | |
507 | |
484 | Sometimes there is a need to do something, but it is not so important |
508 | Repeatedly invoke the callback after the process becomes idle, until |
485 | to do it instantly, but only when there is nothing better to do. This |
509 | either the watcher is destroyed or new events have been detected. |
486 | "nothing better to do" is usually defined to be "no other events need |
|
|
487 | attention by the event loop". |
|
|
488 | |
510 | |
489 | Idle watchers ideally get invoked when the event loop has nothing |
511 | Idle watchers are useful when there is a need to do something, but it |
490 | better to do, just before it would block the process to wait for new |
512 | is not so important (or wise) to do it instantly. The callback will be |
491 | events. Instead of blocking, the idle watcher is invoked. |
513 | invoked only when there is "nothing better to do", which is usually |
|
|
514 | defined as "all outstanding events have been handled and no new events |
|
|
515 | have been detected". That means that idle watchers ideally get invoked |
|
|
516 | when the event loop has just polled for new events but none have been |
|
|
517 | detected. Instead of blocking to wait for more events, the idle watchers |
|
|
518 | will be invoked. |
492 | |
519 | |
493 | Most event loops unfortunately do not really support idle watchers (only |
520 | Unfortunately, most event loops do not really support idle watchers (only |
494 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
521 | EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent |
495 | will simply call the callback "from time to time". |
522 | will simply call the callback "from time to time". |
496 | |
523 | |
497 | Example: read lines from STDIN, but only process them when the |
524 | Example: read lines from STDIN, but only process them when the |
498 | program is otherwise idle: |
525 | program is otherwise idle: |
… | |
… | |
942 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
969 | You should check C<$AnyEvent::MODEL> before adding to this array, though: |
943 | if it is defined then the event loop has already been detected, and the |
970 | if it is defined then the event loop has already been detected, and the |
944 | array will be ignored. |
971 | array will be ignored. |
945 | |
972 | |
946 | Best use C<AnyEvent::post_detect { BLOCK }> when your application allows |
973 | Best use C<AnyEvent::post_detect { BLOCK }> when your application allows |
947 | it,as it takes care of these details. |
974 | it, as it takes care of these details. |
948 | |
975 | |
949 | This variable is mainly useful for modules that can do something useful |
976 | This variable is mainly useful for modules that can do something useful |
950 | when AnyEvent is used and thus want to know when it is initialised, but do |
977 | when AnyEvent is used and thus want to know when it is initialised, but do |
951 | not need to even load it by default. This array provides the means to hook |
978 | not need to even load it by default. This array provides the means to hook |
952 | into AnyEvent passively, without loading it. |
979 | into AnyEvent passively, without loading it. |
|
|
980 | |
|
|
981 | Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used |
|
|
982 | together, you could put this into Coro (this is the actual code used by |
|
|
983 | Coro to accomplish this): |
|
|
984 | |
|
|
985 | if (defined $AnyEvent::MODEL) { |
|
|
986 | # AnyEvent already initialised, so load Coro::AnyEvent |
|
|
987 | require Coro::AnyEvent; |
|
|
988 | } else { |
|
|
989 | # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent |
|
|
990 | # as soon as it is |
|
|
991 | push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; |
|
|
992 | } |
953 | |
993 | |
954 | =back |
994 | =back |
955 | |
995 | |
956 | =head1 WHAT TO DO IN A MODULE |
996 | =head1 WHAT TO DO IN A MODULE |
957 | |
997 | |
… | |
… | |
1107 | package AnyEvent; |
1147 | package AnyEvent; |
1108 | |
1148 | |
1109 | # basically a tuned-down version of common::sense |
1149 | # basically a tuned-down version of common::sense |
1110 | sub common_sense { |
1150 | sub common_sense { |
1111 | # from common:.sense 1.0 |
1151 | # from common:.sense 1.0 |
1112 | ${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03"; |
1152 | ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00"; |
1113 | # use strict vars subs |
1153 | # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl) |
1114 | $^H |= 0x00000600; |
1154 | $^H |= 0x00000600; |
1115 | } |
1155 | } |
1116 | |
1156 | |
1117 | BEGIN { AnyEvent::common_sense } |
1157 | BEGIN { AnyEvent::common_sense } |
1118 | |
1158 | |
1119 | use Carp (); |
1159 | use Carp (); |
1120 | |
1160 | |
1121 | our $VERSION = '5.12'; |
1161 | our $VERSION = '5.24'; |
1122 | our $MODEL; |
1162 | our $MODEL; |
1123 | |
1163 | |
1124 | our $AUTOLOAD; |
1164 | our $AUTOLOAD; |
1125 | our @ISA; |
1165 | our @ISA; |
1126 | |
1166 | |
1127 | our @REGISTRY; |
1167 | our @REGISTRY; |
1128 | |
1168 | |
1129 | our $WIN32; |
|
|
1130 | |
|
|
1131 | our $VERBOSE; |
1169 | our $VERBOSE; |
1132 | |
1170 | |
1133 | BEGIN { |
1171 | BEGIN { |
|
|
1172 | eval "sub CYGWIN(){" . (($^O =~ /cygwin/i) *1) . "}"; |
1134 | eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; |
1173 | eval "sub WIN32 (){" . (($^O =~ /mswin32/i)*1) . "}"; |
1135 | eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; |
1174 | eval "sub TAINT (){" . (${^TAINT} *1) . "}"; |
1136 | |
1175 | |
1137 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
1176 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
1138 | if ${^TAINT}; |
1177 | if ${^TAINT}; |
1139 | |
1178 | |
1140 | $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
1179 | $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
… | |
… | |
1351 | warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; |
1390 | warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; |
1352 | *_time = \&Time::HiRes::time; |
1391 | *_time = \&Time::HiRes::time; |
1353 | # if (eval "use POSIX (); (POSIX::times())... |
1392 | # if (eval "use POSIX (); (POSIX::times())... |
1354 | } else { |
1393 | } else { |
1355 | warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; |
1394 | warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; |
1356 | *_time = sub { time }; # epic fail |
1395 | *_time = sub (){ time }; # epic fail |
1357 | } |
1396 | } |
1358 | |
1397 | |
1359 | &_time |
1398 | &_time |
1360 | } |
1399 | } |
1361 | |
1400 | |
… | |
… | |
1386 | our ($SIG_COUNT, $SIG_TW); |
1425 | our ($SIG_COUNT, $SIG_TW); |
1387 | |
1426 | |
1388 | sub _signal_exec { |
1427 | sub _signal_exec { |
1389 | $HAVE_ASYNC_INTERRUPT |
1428 | $HAVE_ASYNC_INTERRUPT |
1390 | ? $SIGPIPE_R->drain |
1429 | ? $SIGPIPE_R->drain |
1391 | : sysread $SIGPIPE_R, my $dummy, 9; |
1430 | : sysread $SIGPIPE_R, (my $dummy), 9; |
1392 | |
1431 | |
1393 | while (%SIG_EV) { |
1432 | while (%SIG_EV) { |
1394 | for (keys %SIG_EV) { |
1433 | for (keys %SIG_EV) { |
1395 | delete $SIG_EV{$_}; |
1434 | delete $SIG_EV{$_}; |
1396 | $_->() for values %{ $SIG_CB{$_} || {} }; |
1435 | $_->() for values %{ $SIG_CB{$_} || {} }; |
… | |
… | |
2426 | it's built-in modules) are required to use it. |
2465 | it's built-in modules) are required to use it. |
2427 | |
2466 | |
2428 | That does not mean that AnyEvent won't take advantage of some additional |
2467 | That does not mean that AnyEvent won't take advantage of some additional |
2429 | modules if they are installed. |
2468 | modules if they are installed. |
2430 | |
2469 | |
2431 | This section epxlains which additional modules will be used, and how they |
2470 | This section explains which additional modules will be used, and how they |
2432 | affect AnyEvent's operetion. |
2471 | affect AnyEvent's operation. |
2433 | |
2472 | |
2434 | =over 4 |
2473 | =over 4 |
2435 | |
2474 | |
2436 | =item L<Async::Interrupt> |
2475 | =item L<Async::Interrupt> |
2437 | |
2476 | |
… | |
… | |
2442 | catch the signals) with some delay (default is 10 seconds, look for |
2481 | catch the signals) with some delay (default is 10 seconds, look for |
2443 | C<$AnyEvent::MAX_SIGNAL_LATENCY>). |
2482 | C<$AnyEvent::MAX_SIGNAL_LATENCY>). |
2444 | |
2483 | |
2445 | If this module is available, then it will be used to implement signal |
2484 | If this module is available, then it will be used to implement signal |
2446 | catching, which means that signals will not be delayed, and the event loop |
2485 | catching, which means that signals will not be delayed, and the event loop |
2447 | will not be interrupted regularly, which is more efficient (And good for |
2486 | will not be interrupted regularly, which is more efficient (and good for |
2448 | battery life on laptops). |
2487 | battery life on laptops). |
2449 | |
2488 | |
2450 | This affects not just the pure-perl event loop, but also other event loops |
2489 | This affects not just the pure-perl event loop, but also other event loops |
2451 | that have no signal handling on their own (e.g. Glib, Tk, Qt). |
2490 | that have no signal handling on their own (e.g. Glib, Tk, Qt). |
2452 | |
2491 | |
… | |
… | |
2499 | |
2538 | |
2500 | |
2539 | |
2501 | =head1 FORK |
2540 | =head1 FORK |
2502 | |
2541 | |
2503 | Most event libraries are not fork-safe. The ones who are usually are |
2542 | Most event libraries are not fork-safe. The ones who are usually are |
2504 | because they rely on inefficient but fork-safe C<select> or C<poll> |
2543 | because they rely on inefficient but fork-safe C<select> or C<poll> calls |
2505 | calls. Only L<EV> is fully fork-aware. |
2544 | - higher performance APIs such as BSD's kqueue or the dreaded Linux epoll |
|
|
2545 | are usually badly thought-out hacks that are incompatible with fork in |
|
|
2546 | one way or another. Only L<EV> is fully fork-aware and ensures that you |
|
|
2547 | continue event-processing in both parent and child (or both, if you know |
|
|
2548 | what you are doing). |
|
|
2549 | |
|
|
2550 | This means that, in general, you cannot fork and do event processing in |
|
|
2551 | the child if the event library was initialised before the fork (which |
|
|
2552 | usually happens when the first AnyEvent watcher is created, or the library |
|
|
2553 | is loaded). |
2506 | |
2554 | |
2507 | If you have to fork, you must either do so I<before> creating your first |
2555 | If you have to fork, you must either do so I<before> creating your first |
2508 | watcher OR you must not use AnyEvent at all in the child OR you must do |
2556 | watcher OR you must not use AnyEvent at all in the child OR you must do |
2509 | something completely out of the scope of AnyEvent. |
2557 | something completely out of the scope of AnyEvent. |
|
|
2558 | |
|
|
2559 | The problem of doing event processing in the parent I<and> the child |
|
|
2560 | is much more complicated: even for backends that I<are> fork-aware or |
|
|
2561 | fork-safe, their behaviour is not usually what you want: fork clones all |
|
|
2562 | watchers, that means all timers, I/O watchers etc. are active in both |
|
|
2563 | parent and child, which is almost never what you want. USing C<exec> |
|
|
2564 | to start worker children from some kind of manage rprocess is usually |
|
|
2565 | preferred, because it is much easier and cleaner, at the expense of having |
|
|
2566 | to have another binary. |
2510 | |
2567 | |
2511 | |
2568 | |
2512 | =head1 SECURITY CONSIDERATIONS |
2569 | =head1 SECURITY CONSIDERATIONS |
2513 | |
2570 | |
2514 | AnyEvent can be forced to load any event model via |
2571 | AnyEvent can be forced to load any event model via |