… | |
… | |
350 | invocation, and callback invocation will be synchronous. Synchronous |
350 | invocation, and callback invocation will be synchronous. Synchronous |
351 | means that it might take a while until the signal gets handled by the |
351 | means that it might take a while until the signal gets handled by the |
352 | process, but it is guaranteed not to interrupt any other callbacks. |
352 | process, but it is guaranteed not to interrupt any other callbacks. |
353 | |
353 | |
354 | The main advantage of using these watchers is that you can share a |
354 | The main advantage of using these watchers is that you can share a |
355 | signal between multiple watchers. |
355 | signal between multiple watchers, and AnyEvent will ensure that signals |
|
|
356 | will not interrupt your program at bad times. |
356 | |
357 | |
357 | This watcher might use %SIG, so programs overwriting those signals |
358 | This watcher might use %SIG (depending on the event loop used), so |
358 | directly will likely not work correctly. |
359 | programs overwriting those signals directly will likely not work |
|
|
360 | correctly. |
|
|
361 | |
|
|
362 | Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not |
|
|
363 | support attaching callbacks to signals, which is a pity, as you cannot |
|
|
364 | do race-free signal handling in perl. AnyEvent will try to do it's best, |
|
|
365 | but in some cases, signals will be delayed. The maximum time a signal |
|
|
366 | might be delayed is specified in $AnyEvent::MAX_SIGNAL_LATENCY (default: |
|
|
367 | 10 seconds). This variable can be changed only before the first signal |
|
|
368 | watcher is created, and should be left alone otherwise. Higher values |
|
|
369 | will cause fewer spurious wake-ups, which is better for power and CPU |
|
|
370 | saving. All these problems can be avoided by installing the optional |
|
|
371 | Async::Interrupt module. |
359 | |
372 | |
360 | Example: exit on SIGINT |
373 | Example: exit on SIGINT |
361 | |
374 | |
362 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
375 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
363 | |
376 | |
… | |
… | |
390 | of when you start the watcher. |
403 | of when you start the watcher. |
391 | |
404 | |
392 | This means you cannot create a child watcher as the very first thing in |
405 | This means you cannot create a child watcher as the very first thing in |
393 | an AnyEvent program, you *have* to create at least one watcher before |
406 | an AnyEvent program, you *have* to create at least one watcher before |
394 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
407 | you "fork" the child (alternatively, you can call "AnyEvent::detect"). |
|
|
408 | |
|
|
409 | As most event loops do not support waiting for child events, they will |
|
|
410 | be emulated by AnyEvent in most cases, in which the latency and race |
|
|
411 | problems mentioned in the description of signal watchers apply. |
395 | |
412 | |
396 | Example: fork a process and wait for it |
413 | Example: fork a process and wait for it |
397 | |
414 | |
398 | my $done = AnyEvent->condvar; |
415 | my $done = AnyEvent->condvar; |
399 | |
416 | |
… | |
… | |
991 | by "PERL_ANYEVENT_MODEL". |
1008 | by "PERL_ANYEVENT_MODEL". |
992 | |
1009 | |
993 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
1010 | When set to 2 or higher, cause AnyEvent to report to STDERR which |
994 | event model it chooses. |
1011 | event model it chooses. |
995 | |
1012 | |
|
|
1013 | When set to 8 or higher, then AnyEvent will report extra information |
|
|
1014 | on which optional modules it loads and how it implements certain |
|
|
1015 | features. |
|
|
1016 | |
996 | "PERL_ANYEVENT_STRICT" |
1017 | "PERL_ANYEVENT_STRICT" |
997 | AnyEvent does not do much argument checking by default, as thorough |
1018 | AnyEvent does not do much argument checking by default, as thorough |
998 | argument checking is very costly. Setting this variable to a true |
1019 | argument checking is very costly. Setting this variable to a true |
999 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1020 | value will cause AnyEvent to load "AnyEvent::Strict" and then to |
1000 | thoroughly check the arguments passed to most method calls. If it |
1021 | thoroughly check the arguments passed to most method calls. If it |
1001 | finds any problems, it will croak. |
1022 | finds any problems, it will croak. |
1002 | |
1023 | |
1003 | In other words, enables "strict" mode. |
1024 | In other words, enables "strict" mode. |
1004 | |
1025 | |
1005 | Unlike "use strict", it is definitely recommended to keep it off in |
1026 | Unlike "use strict" (or it's modern cousin, "use common::sense", it |
1006 | production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment |
1027 | is definitely recommended to keep it off in production. Keeping |
|
|
1028 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1007 | while developing programs can be very useful, however. |
1029 | programs can be very useful, however. |
1008 | |
1030 | |
1009 | "PERL_ANYEVENT_MODEL" |
1031 | "PERL_ANYEVENT_MODEL" |
1010 | This can be used to specify the event model to be used by AnyEvent, |
1032 | This can be used to specify the event model to be used by AnyEvent, |
1011 | before auto detection and -probing kicks in. It must be a string |
1033 | before auto detection and -probing kicks in. It must be a string |
1012 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
1034 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
… | |
… | |
1069 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1091 | "PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH". |
1070 | When neither "ca_file" nor "ca_path" was specified during |
1092 | When neither "ca_file" nor "ca_path" was specified during |
1071 | AnyEvent::TLS context creation, and either of these environment |
1093 | AnyEvent::TLS context creation, and either of these environment |
1072 | variables exist, they will be used to specify CA certificate |
1094 | variables exist, they will be used to specify CA certificate |
1073 | locations instead of a system-dependent default. |
1095 | locations instead of a system-dependent default. |
|
|
1096 | |
|
|
1097 | "PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT" |
|
|
1098 | When these are set to 1, then the respective modules are not loaded. |
|
|
1099 | Mostly good for testing AnyEvent itself. |
1074 | |
1100 | |
1075 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1101 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
1076 | This is an advanced topic that you do not normally need to use AnyEvent |
1102 | This is an advanced topic that you do not normally need to use AnyEvent |
1077 | in a module. This section is only of use to event loop authors who want |
1103 | in a module. This section is only of use to event loop authors who want |
1078 | to provide AnyEvent compatibility. |
1104 | to provide AnyEvent compatibility. |
… | |
… | |
1603 | it is that this way, the handler will be restored to defaults on |
1629 | it is that this way, the handler will be restored to defaults on |
1604 | exec. |
1630 | exec. |
1605 | |
1631 | |
1606 | Feel free to install your own handler, or reset it to defaults. |
1632 | Feel free to install your own handler, or reset it to defaults. |
1607 | |
1633 | |
|
|
1634 | RECOMMENDED/OPTIONAL MODULES |
|
|
1635 | One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and |
|
|
1636 | it's built-in modules) are required to use it. |
|
|
1637 | |
|
|
1638 | That does not mean that AnyEvent won't take advantage of some additional |
|
|
1639 | modules if they are installed. |
|
|
1640 | |
|
|
1641 | This section epxlains which additional modules will be used, and how |
|
|
1642 | they affect AnyEvent's operetion. |
|
|
1643 | |
|
|
1644 | Async::Interrupt |
|
|
1645 | This slightly arcane module is used to implement fast signal |
|
|
1646 | handling: To my knowledge, there is no way to do completely |
|
|
1647 | race-free and quick signal handling in pure perl. To ensure that |
|
|
1648 | signals still get delivered, AnyEvent will start an interval timer |
|
|
1649 | to wake up perl (and catch the signals) with soemd elay (default is |
|
|
1650 | 10 seconds, look for $AnyEvent::MAX_SIGNAL_LATENCY). |
|
|
1651 | |
|
|
1652 | If this module is available, then it will be used to implement |
|
|
1653 | signal catching, which means that signals will not be delayed, and |
|
|
1654 | the event loop will not be interrupted regularly, which is more |
|
|
1655 | efficient (And good for battery life on laptops). |
|
|
1656 | |
|
|
1657 | This affects not just the pure-perl event loop, but also other event |
|
|
1658 | loops that have no signal handling on their own (e.g. Glib, Tk, Qt). |
|
|
1659 | |
|
|
1660 | EV This module isn't really "optional", as it is simply one of the |
|
|
1661 | backend event loops that AnyEvent can use. However, it is simply the |
|
|
1662 | best event loop available in terms of features, speed and stability: |
|
|
1663 | It supports the AnyEvent API optimally, implements all the watcher |
|
|
1664 | types in XS, does automatic timer adjustments even when no monotonic |
|
|
1665 | clock is available, can take avdantage of advanced kernel interfaces |
|
|
1666 | such as "epoll" and "kqueue", and is the fastest backend *by far*. |
|
|
1667 | You can even embed Glib/Gtk2 in it (or vice versa, see EV::Glib and |
|
|
1668 | Glib::EV). |
|
|
1669 | |
|
|
1670 | Guard |
|
|
1671 | The guard module, when used, will be used to implement |
|
|
1672 | "AnyEvent::Util::guard". This speeds up guards considerably (and |
|
|
1673 | uses a lot less memory), but otherwise doesn't affect guard |
|
|
1674 | operation much. It is purely used for performance. |
|
|
1675 | |
|
|
1676 | JSON and JSON::XS |
|
|
1677 | This module is required when you want to read or write JSON data via |
|
|
1678 | AnyEvent::Handle. It is also written in pure-perl, but can take |
|
|
1679 | advantage of the ulta-high-speed JSON::XS module when it is |
|
|
1680 | installed. |
|
|
1681 | |
|
|
1682 | In fact, AnyEvent::Handle will use JSON::XS by default if it is |
|
|
1683 | installed. |
|
|
1684 | |
|
|
1685 | Net::SSLeay |
|
|
1686 | Implementing TLS/SSL in Perl is certainly interesting, but not very |
|
|
1687 | worthwhile: If this module is installed, then AnyEvent::Handle (with |
|
|
1688 | the help of AnyEvent::TLS), gains the ability to do TLS/SSL. |
|
|
1689 | |
|
|
1690 | Time::HiRes |
|
|
1691 | This module is part of perl since release 5.008. It will be used |
|
|
1692 | when the chosen event library does not come with a timing source on |
|
|
1693 | it's own. The pure-perl event loop (AnyEvent::Impl::Perl) will |
|
|
1694 | additionally use it to try to use a monotonic clock for timing |
|
|
1695 | stability. |
|
|
1696 | |
1608 | FORK |
1697 | FORK |
1609 | Most event libraries are not fork-safe. The ones who are usually are |
1698 | Most event libraries are not fork-safe. The ones who are usually are |
1610 | because they rely on inefficient but fork-safe "select" or "poll" calls. |
1699 | because they rely on inefficient but fork-safe "select" or "poll" calls. |
1611 | Only EV is fully fork-aware. |
1700 | Only EV is fully fork-aware. |
1612 | |
1701 | |
1613 | If you have to fork, you must either do so *before* creating your first |
1702 | If you have to fork, you must either do so *before* creating your first |
1614 | watcher OR you must not use AnyEvent at all in the child. |
1703 | watcher OR you must not use AnyEvent at all in the child OR you must do |
|
|
1704 | something completely out of the scope of AnyEvent. |
1615 | |
1705 | |
1616 | SECURITY CONSIDERATIONS |
1706 | SECURITY CONSIDERATIONS |
1617 | AnyEvent can be forced to load any event model via |
1707 | AnyEvent can be forced to load any event model via |
1618 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1708 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used |
1619 | to execute arbitrary code or directly gain access, it can easily be used |
1709 | to execute arbitrary code or directly gain access, it can easily be used |