… | |
… | |
330 | |
330 | |
331 | CHILD PROCESS WATCHERS |
331 | CHILD PROCESS WATCHERS |
332 | You can also watch on a child process exit and catch its exit status. |
332 | You can also watch on a child process exit and catch its exit status. |
333 | |
333 | |
334 | The child process is specified by the "pid" argument (if set to 0, it |
334 | The child process is specified by the "pid" argument (if set to 0, it |
335 | watches for any child process exit). The watcher will trigger as often |
335 | watches for any child process exit). The watcher will triggered only |
336 | as status change for the child are received. This works by installing a |
336 | when the child process has finished and an exit status is available, not |
337 | signal handler for "SIGCHLD". The callback will be called with the pid |
337 | on any trace events (stopped/continued). |
338 | and exit status (as returned by waitpid), so unlike other watcher types, |
338 | |
339 | you *can* rely on child watcher callback arguments. |
339 | The callback will be called with the pid and exit status (as returned by |
|
|
340 | waitpid), so unlike other watcher types, you *can* rely on child watcher |
|
|
341 | callback arguments. |
|
|
342 | |
|
|
343 | This watcher type works by installing a signal handler for "SIGCHLD", |
|
|
344 | and since it cannot be shared, nothing else should use SIGCHLD or reap |
|
|
345 | random child processes (waiting for specific child processes, e.g. |
|
|
346 | inside "system", is just fine). |
340 | |
347 | |
341 | There is a slight catch to child watchers, however: you usually start |
348 | There is a slight catch to child watchers, however: you usually start |
342 | them *after* the child process was created, and this means the process |
349 | them *after* the child process was created, and this means the process |
343 | could have exited already (and no SIGCHLD will be sent anymore). |
350 | could have exited already (and no SIGCHLD will be sent anymore). |
344 | |
351 | |
… | |
… | |
770 | |
777 | |
771 | AnyEvent::IGS |
778 | AnyEvent::IGS |
772 | A non-blocking interface to the Internet Go Server protocol (used by |
779 | A non-blocking interface to the Internet Go Server protocol (used by |
773 | App::IGS). |
780 | App::IGS). |
774 | |
781 | |
|
|
782 | AnyEvent::IRC |
|
|
783 | AnyEvent based IRC client module family (replacing the older |
775 | Net::IRC3 |
784 | Net::IRC3). |
776 | AnyEvent based IRC client module family. |
|
|
777 | |
785 | |
778 | Net::XMPP2 |
786 | Net::XMPP2 |
779 | AnyEvent based XMPP (Jabber protocol) module family. |
787 | AnyEvent based XMPP (Jabber protocol) module family. |
780 | |
788 | |
781 | Net::FCP |
789 | Net::FCP |
… | |
… | |
790 | |
798 | |
791 | IO::Lambda |
799 | IO::Lambda |
792 | The lambda approach to I/O - don't ask, look there. Can use |
800 | The lambda approach to I/O - don't ask, look there. Can use |
793 | AnyEvent. |
801 | AnyEvent. |
794 | |
802 | |
795 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
803 | ERROR AND EXCEPTION HANDLING |
796 | This is an advanced topic that you do not normally need to use AnyEvent |
804 | In general, AnyEvent does not do any error handling - it relies on the |
797 | in a module. This section is only of use to event loop authors who want |
805 | caller to do that if required. The AnyEvent::Strict module (see also the |
798 | to provide AnyEvent compatibility. |
806 | "PERL_ANYEVENT_STRICT" environment variable, below) provides strict |
|
|
807 | checking of all AnyEvent methods, however, which is highly useful during |
|
|
808 | development. |
799 | |
809 | |
800 | If you need to support another event library which isn't directly |
810 | As for exception handling (i.e. runtime errors and exceptions thrown |
801 | supported by AnyEvent, you can supply your own interface to it by |
811 | while executing a callback), this is not only highly event-loop |
802 | pushing, before the first watcher gets created, the package name of the |
812 | specific, but also not in any way wrapped by this module, as this is the |
803 | event module and the package name of the interface to use onto |
813 | job of the main program. |
804 | @AnyEvent::REGISTRY. You can do that before and even without loading |
|
|
805 | AnyEvent, so it is reasonably cheap. |
|
|
806 | |
814 | |
807 | Example: |
815 | The pure perl event loop simply re-throws the exception (usually within |
808 | |
816 | "condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()", |
809 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
817 | Glib uses "install_exception_handler" and so on. |
810 | |
|
|
811 | This tells AnyEvent to (literally) use the "urxvt::anyevent::" |
|
|
812 | package/class when it finds the "urxvt" package/module is already |
|
|
813 | loaded. |
|
|
814 | |
|
|
815 | When AnyEvent is loaded and asked to find a suitable event model, it |
|
|
816 | will first check for the presence of urxvt by trying to "use" the |
|
|
817 | "urxvt::anyevent" module. |
|
|
818 | |
|
|
819 | The class should provide implementations for all watcher types. See |
|
|
820 | AnyEvent::Impl::EV (source code), AnyEvent::Impl::Glib (Source code) and |
|
|
821 | so on for actual examples. Use "perldoc -m AnyEvent::Impl::Glib" to see |
|
|
822 | the sources. |
|
|
823 | |
|
|
824 | If you don't provide "signal" and "child" watchers than AnyEvent will |
|
|
825 | provide suitable (hopefully) replacements. |
|
|
826 | |
|
|
827 | The above example isn't fictitious, the *rxvt-unicode* (a.k.a. urxvt) |
|
|
828 | terminal emulator uses the above line as-is. An interface isn't included |
|
|
829 | in AnyEvent because it doesn't make sense outside the embedded |
|
|
830 | interpreter inside *rxvt-unicode*, and it is updated and maintained as |
|
|
831 | part of the *rxvt-unicode* distribution. |
|
|
832 | |
|
|
833 | *rxvt-unicode* also cheats a bit by not providing blocking access to |
|
|
834 | condition variables: code blocking while waiting for a condition will |
|
|
835 | "die". This still works with most modules/usages, and blocking calls |
|
|
836 | must not be done in an interactive application, so it makes sense. |
|
|
837 | |
818 | |
838 | ENVIRONMENT VARIABLES |
819 | ENVIRONMENT VARIABLES |
839 | The following environment variables are used by this module: |
820 | The following environment variables are used by this module or its |
|
|
821 | submodules: |
840 | |
822 | |
841 | "PERL_ANYEVENT_VERBOSE" |
823 | "PERL_ANYEVENT_VERBOSE" |
842 | By default, AnyEvent will be completely silent except in fatal |
824 | By default, AnyEvent will be completely silent except in fatal |
843 | conditions. You can set this environment variable to make AnyEvent |
825 | conditions. You can set this environment variable to make AnyEvent |
844 | more talkative. |
826 | more talkative. |
… | |
… | |
857 | thoroughly check the arguments passed to most method calls. If it |
839 | thoroughly check the arguments passed to most method calls. If it |
858 | finds any problems it will croak. |
840 | finds any problems it will croak. |
859 | |
841 | |
860 | In other words, enables "strict" mode. |
842 | In other words, enables "strict" mode. |
861 | |
843 | |
862 | Unlike "use strict" it is definitely recommended ot keep it off in |
844 | Unlike "use strict", it is definitely recommended ot keep it off in |
863 | production. |
845 | production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment |
|
|
846 | while developing programs can be very useful, however. |
864 | |
847 | |
865 | "PERL_ANYEVENT_MODEL" |
848 | "PERL_ANYEVENT_MODEL" |
866 | This can be used to specify the event model to be used by AnyEvent, |
849 | This can be used to specify the event model to be used by AnyEvent, |
867 | before auto detection and -probing kicks in. It must be a string |
850 | before auto detection and -probing kicks in. It must be a string |
868 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
851 | consisting entirely of ASCII letters. The string "AnyEvent::Impl::" |
… | |
… | |
909 | EDNS0 in its DNS requests. |
892 | EDNS0 in its DNS requests. |
910 | |
893 | |
911 | "PERL_ANYEVENT_MAX_FORKS" |
894 | "PERL_ANYEVENT_MAX_FORKS" |
912 | The maximum number of child processes that |
895 | The maximum number of child processes that |
913 | "AnyEvent::Util::fork_call" will create in parallel. |
896 | "AnyEvent::Util::fork_call" will create in parallel. |
|
|
897 | |
|
|
898 | SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
|
|
899 | This is an advanced topic that you do not normally need to use AnyEvent |
|
|
900 | in a module. This section is only of use to event loop authors who want |
|
|
901 | to provide AnyEvent compatibility. |
|
|
902 | |
|
|
903 | If you need to support another event library which isn't directly |
|
|
904 | supported by AnyEvent, you can supply your own interface to it by |
|
|
905 | pushing, before the first watcher gets created, the package name of the |
|
|
906 | event module and the package name of the interface to use onto |
|
|
907 | @AnyEvent::REGISTRY. You can do that before and even without loading |
|
|
908 | AnyEvent, so it is reasonably cheap. |
|
|
909 | |
|
|
910 | Example: |
|
|
911 | |
|
|
912 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
|
|
913 | |
|
|
914 | This tells AnyEvent to (literally) use the "urxvt::anyevent::" |
|
|
915 | package/class when it finds the "urxvt" package/module is already |
|
|
916 | loaded. |
|
|
917 | |
|
|
918 | When AnyEvent is loaded and asked to find a suitable event model, it |
|
|
919 | will first check for the presence of urxvt by trying to "use" the |
|
|
920 | "urxvt::anyevent" module. |
|
|
921 | |
|
|
922 | The class should provide implementations for all watcher types. See |
|
|
923 | AnyEvent::Impl::EV (source code), AnyEvent::Impl::Glib (Source code) and |
|
|
924 | so on for actual examples. Use "perldoc -m AnyEvent::Impl::Glib" to see |
|
|
925 | the sources. |
|
|
926 | |
|
|
927 | If you don't provide "signal" and "child" watchers than AnyEvent will |
|
|
928 | provide suitable (hopefully) replacements. |
|
|
929 | |
|
|
930 | The above example isn't fictitious, the *rxvt-unicode* (a.k.a. urxvt) |
|
|
931 | terminal emulator uses the above line as-is. An interface isn't included |
|
|
932 | in AnyEvent because it doesn't make sense outside the embedded |
|
|
933 | interpreter inside *rxvt-unicode*, and it is updated and maintained as |
|
|
934 | part of the *rxvt-unicode* distribution. |
|
|
935 | |
|
|
936 | *rxvt-unicode* also cheats a bit by not providing blocking access to |
|
|
937 | condition variables: code blocking while waiting for a condition will |
|
|
938 | "die". This still works with most modules/usages, and blocking calls |
|
|
939 | must not be done in an interactive application, so it makes sense. |
914 | |
940 | |
915 | EXAMPLE PROGRAM |
941 | EXAMPLE PROGRAM |
916 | The following program uses an I/O watcher to read data from STDIN, a |
942 | The following program uses an I/O watcher to read data from STDIN, a |
917 | timer to display a message once per second, and a condition variable to |
943 | timer to display a message once per second, and a condition variable to |
918 | quit the program when the user enters quit: |
944 | quit the program when the user enters quit: |