… | |
… | |
392 | |
392 | |
393 | There is a slight catch to child watchers, however: you usually start them |
393 | There is a slight catch to child watchers, however: you usually start them |
394 | I<after> the child process was created, and this means the process could |
394 | I<after> the child process was created, and this means the process could |
395 | have exited already (and no SIGCHLD will be sent anymore). |
395 | have exited already (and no SIGCHLD will be sent anymore). |
396 | |
396 | |
397 | Not all event models handle this correctly (POE doesn't), but even for |
397 | Not all event models handle this correctly (neither POE nor IO::Async do, |
|
|
398 | see their AnyEvent::Impl manpages for details), but even for event models |
398 | event models that I<do> handle this correctly, they usually need to be |
399 | that I<do> handle this correctly, they usually need to be loaded before |
399 | loaded before the process exits (i.e. before you fork in the first place). |
400 | the process exits (i.e. before you fork in the first place). AnyEvent's |
|
|
401 | pure perl event loop handles all cases correctly regardless of when you |
|
|
402 | start the watcher. |
400 | |
403 | |
401 | This means you cannot create a child watcher as the very first thing in an |
404 | This means you cannot create a child watcher as the very first |
402 | AnyEvent program, you I<have> to create at least one watcher before you |
405 | thing in an AnyEvent program, you I<have> to create at least one |
403 | C<fork> the child (alternatively, you can call C<AnyEvent::detect>). |
406 | watcher before you C<fork> the child (alternatively, you can call |
|
|
407 | C<AnyEvent::detect>). |
404 | |
408 | |
405 | Example: fork a process and wait for it |
409 | Example: fork a process and wait for it |
406 | |
410 | |
407 | my $done = AnyEvent->condvar; |
411 | my $done = AnyEvent->condvar; |
408 | |
412 | |
… | |
… | |
730 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
734 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
731 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
735 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
732 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
736 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
733 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
737 | AnyEvent::Impl::POE based on POE, not generic enough for full support. |
734 | |
738 | |
|
|
739 | # warning, support for IO::Async is only partial, as it is too broken |
|
|
740 | # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async. |
|
|
741 | AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs). |
|
|
742 | |
735 | There is no support for WxWidgets, as WxWidgets has no support for |
743 | There is no support for WxWidgets, as WxWidgets has no support for |
736 | watching file handles. However, you can use WxWidgets through the |
744 | watching file handles. However, you can use WxWidgets through the |
737 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
745 | POE Adaptor, as POE has a Wx backend that simply polls 20 times per |
738 | second, which was considered to be too horrible to even consider for |
746 | second, which was considered to be too horrible to even consider for |
739 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
747 | AnyEvent. Likewise, other POE backends can be used by AnyEvent by using |
… | |
… | |
931 | no warnings; |
939 | no warnings; |
932 | use strict qw(vars subs); |
940 | use strict qw(vars subs); |
933 | |
941 | |
934 | use Carp; |
942 | use Carp; |
935 | |
943 | |
936 | our $VERSION = 4.41; |
944 | our $VERSION = 4.412; |
937 | our $MODEL; |
945 | our $MODEL; |
938 | |
946 | |
939 | our $AUTOLOAD; |
947 | our $AUTOLOAD; |
940 | our @ISA; |
948 | our @ISA; |
941 | |
949 | |
942 | our @REGISTRY; |
950 | our @REGISTRY; |
943 | |
951 | |
944 | our $WIN32; |
952 | our $WIN32; |
945 | |
953 | |
946 | BEGIN { |
954 | BEGIN { |
947 | my $win32 = ! ! ($^O =~ /mswin32/i); |
955 | eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; |
948 | eval "sub WIN32(){ $win32 }"; |
956 | eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; |
|
|
957 | |
|
|
958 | delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} |
|
|
959 | if ${^TAINT}; |
949 | } |
960 | } |
950 | |
961 | |
951 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
962 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
952 | |
963 | |
953 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
964 | our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred |
… | |
… | |
971 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
982 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
972 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
983 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
973 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
984 | [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza |
974 | [Wx:: => AnyEvent::Impl::POE::], |
985 | [Wx:: => AnyEvent::Impl::POE::], |
975 | [Prima:: => AnyEvent::Impl::POE::], |
986 | [Prima:: => AnyEvent::Impl::POE::], |
|
|
987 | # IO::Async is just too broken - we would need workaorunds for its |
|
|
988 | # byzantine signal and broken child handling, among others. |
|
|
989 | # IO::Async is rather hard to detect, as it doesn't have any |
|
|
990 | # obvious default class. |
|
|
991 | # [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
992 | # [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program |
|
|
993 | # [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program |
976 | ); |
994 | ); |
977 | |
995 | |
978 | our %method = map +($_ => 1), |
996 | our %method = map +($_ => 1), |
979 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
997 | qw(io timer time now now_update signal child idle condvar one_event DESTROY); |
980 | |
998 | |
… | |
… | |
1072 | } |
1090 | } |
1073 | |
1091 | |
1074 | # utility function to dup a filehandle. this is used by many backends |
1092 | # utility function to dup a filehandle. this is used by many backends |
1075 | # to support binding more than one watcher per filehandle (they usually |
1093 | # to support binding more than one watcher per filehandle (they usually |
1076 | # allow only one watcher per fd, so we dup it to get a different one). |
1094 | # allow only one watcher per fd, so we dup it to get a different one). |
1077 | sub _dupfh($$$$) { |
1095 | sub _dupfh($$;$$) { |
1078 | my ($poll, $fh, $r, $w) = @_; |
1096 | my ($poll, $fh, $r, $w) = @_; |
1079 | |
1097 | |
1080 | # cygwin requires the fh mode to be matching, unix doesn't |
1098 | # cygwin requires the fh mode to be matching, unix doesn't |
1081 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") |
1099 | my ($rw, $mode) = $poll eq "r" ? ($r, "<") |
1082 | : $poll eq "w" ? ($w, ">") |
1100 | : $poll eq "w" ? ($w, ">") |
… | |
… | |
1337 | so on. |
1355 | so on. |
1338 | |
1356 | |
1339 | =head1 ENVIRONMENT VARIABLES |
1357 | =head1 ENVIRONMENT VARIABLES |
1340 | |
1358 | |
1341 | The following environment variables are used by this module or its |
1359 | The following environment variables are used by this module or its |
1342 | submodules: |
1360 | submodules. |
|
|
1361 | |
|
|
1362 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
1363 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
1364 | enabled. |
1343 | |
1365 | |
1344 | =over 4 |
1366 | =over 4 |
1345 | |
1367 | |
1346 | =item C<PERL_ANYEVENT_VERBOSE> |
1368 | =item C<PERL_ANYEVENT_VERBOSE> |
1347 | |
1369 | |
… | |
… | |
1359 | =item C<PERL_ANYEVENT_STRICT> |
1381 | =item C<PERL_ANYEVENT_STRICT> |
1360 | |
1382 | |
1361 | AnyEvent does not do much argument checking by default, as thorough |
1383 | AnyEvent does not do much argument checking by default, as thorough |
1362 | argument checking is very costly. Setting this variable to a true value |
1384 | argument checking is very costly. Setting this variable to a true value |
1363 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
1385 | will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly |
1364 | check the arguments passed to most method calls. If it finds any problems |
1386 | check the arguments passed to most method calls. If it finds any problems, |
1365 | it will croak. |
1387 | it will croak. |
1366 | |
1388 | |
1367 | In other words, enables "strict" mode. |
1389 | In other words, enables "strict" mode. |
1368 | |
1390 | |
1369 | Unlike C<use strict>, it is definitely recommended ot keep it off in |
1391 | Unlike C<use strict>, it is definitely recommended to keep it off in |
1370 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
1392 | production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while |
1371 | developing programs can be very useful, however. |
1393 | developing programs can be very useful, however. |
1372 | |
1394 | |
1373 | =item C<PERL_ANYEVENT_MODEL> |
1395 | =item C<PERL_ANYEVENT_MODEL> |
1374 | |
1396 | |
… | |
… | |
1887 | =item * C-based event loops perform very well with small number of |
1909 | =item * C-based event loops perform very well with small number of |
1888 | watchers, as the management overhead dominates. |
1910 | watchers, as the management overhead dominates. |
1889 | |
1911 | |
1890 | =back |
1912 | =back |
1891 | |
1913 | |
|
|
1914 | =head2 THE IO::Lambda BENCHMARK |
|
|
1915 | |
|
|
1916 | Recently I was told about the benchmark in the IO::Lambda manpage, which |
|
|
1917 | could be misinterpreted to make AnyEvent look bad. In fact, the benchmark |
|
|
1918 | simply compares IO::Lambda with POE, and IO::Lambda looks better (which |
|
|
1919 | shouldn't come as a surprise to anybody). As such, the benchmark is |
|
|
1920 | fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't |
|
|
1921 | very optimal. But how would AnyEvent compare when used without the extra |
|
|
1922 | baggage? To explore this, I wrote the equivalent benchmark for AnyEvent. |
|
|
1923 | |
|
|
1924 | The benchmark itself creates an echo-server, and then, for 500 times, |
|
|
1925 | connects to the echo server, sends a line, waits for the reply, and then |
|
|
1926 | creates the next connection. This is a rather bad benchmark, as it doesn't |
|
|
1927 | test the efficiency of the framework or much non-blocking I/O, but it is a |
|
|
1928 | benchmark nevertheless. |
|
|
1929 | |
|
|
1930 | name runtime |
|
|
1931 | Lambda/select 0.330 sec |
|
|
1932 | + optimized 0.122 sec |
|
|
1933 | Lambda/AnyEvent 0.327 sec |
|
|
1934 | + optimized 0.138 sec |
|
|
1935 | Raw sockets/select 0.077 sec |
|
|
1936 | POE/select, components 0.662 sec |
|
|
1937 | POE/select, raw sockets 0.226 sec |
|
|
1938 | POE/select, optimized 0.404 sec |
|
|
1939 | |
|
|
1940 | AnyEvent/select/nb 0.085 sec |
|
|
1941 | AnyEvent/EV/nb 0.068 sec |
|
|
1942 | +state machine 0.134 sec |
|
|
1943 | |
|
|
1944 | The benchmark is also a bit unfair (my fault): the IO::Lambda/POE |
|
|
1945 | benchmarks actually make blocking connects and use 100% blocking I/O, |
|
|
1946 | defeating the purpose of an event-based solution. All of the newly |
|
|
1947 | written AnyEvent benchmarks use 100% non-blocking connects (using |
|
|
1948 | AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS |
|
|
1949 | resolver), so AnyEvent is at a disadvantage here, as non-blocking connects |
|
|
1950 | generally require a lot more bookkeeping and event handling than blocking |
|
|
1951 | connects (which involve a single syscall only). |
|
|
1952 | |
|
|
1953 | The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which |
|
|
1954 | offers similar expressive power as POE and IO::Lambda, using conventional |
|
|
1955 | Perl syntax. This means that both the echo server and the client are 100% |
|
|
1956 | non-blocking, further placing it at a disadvantage. |
|
|
1957 | |
|
|
1958 | As you can see, the AnyEvent + EV combination even beats the |
|
|
1959 | hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl |
|
|
1960 | backend easily beats IO::Lambda and POE. |
|
|
1961 | |
|
|
1962 | And even the 100% non-blocking version written using the high-level (and |
|
|
1963 | slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a |
|
|
1964 | large margin, even though it does all of DNS, tcp-connect and socket I/O |
|
|
1965 | in a non-blocking way. |
|
|
1966 | |
|
|
1967 | The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and |
|
|
1968 | F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are |
|
|
1969 | part of the IO::lambda distribution and were used without any changes. |
|
|
1970 | |
1892 | |
1971 | |
1893 | =head1 SIGNALS |
1972 | =head1 SIGNALS |
1894 | |
1973 | |
1895 | AnyEvent currently installs handlers for these signals: |
1974 | AnyEvent currently installs handlers for these signals: |
1896 | |
1975 | |
… | |
… | |
1899 | =item SIGCHLD |
1978 | =item SIGCHLD |
1900 | |
1979 | |
1901 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
1980 | A handler for C<SIGCHLD> is installed by AnyEvent's child watcher |
1902 | emulation for event loops that do not support them natively. Also, some |
1981 | emulation for event loops that do not support them natively. Also, some |
1903 | event loops install a similar handler. |
1982 | event loops install a similar handler. |
|
|
1983 | |
|
|
1984 | If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will |
|
|
1985 | reset it to default, to avoid losing child exit statuses. |
1904 | |
1986 | |
1905 | =item SIGPIPE |
1987 | =item SIGPIPE |
1906 | |
1988 | |
1907 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
1989 | A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> |
1908 | when AnyEvent gets loaded. |
1990 | when AnyEvent gets loaded. |
… | |
… | |
1920 | |
2002 | |
1921 | =back |
2003 | =back |
1922 | |
2004 | |
1923 | =cut |
2005 | =cut |
1924 | |
2006 | |
|
|
2007 | undef $SIG{CHLD} |
|
|
2008 | if $SIG{CHLD} eq 'IGNORE'; |
|
|
2009 | |
1925 | $SIG{PIPE} = sub { } |
2010 | $SIG{PIPE} = sub { } |
1926 | unless defined $SIG{PIPE}; |
2011 | unless defined $SIG{PIPE}; |
1927 | |
|
|
1928 | |
2012 | |
1929 | =head1 FORK |
2013 | =head1 FORK |
1930 | |
2014 | |
1931 | Most event libraries are not fork-safe. The ones who are usually are |
2015 | Most event libraries are not fork-safe. The ones who are usually are |
1932 | because they rely on inefficient but fork-safe C<select> or C<poll> |
2016 | because they rely on inefficient but fork-safe C<select> or C<poll> |
… | |
… | |
1953 | use AnyEvent; |
2037 | use AnyEvent; |
1954 | |
2038 | |
1955 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
2039 | Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can |
1956 | be used to probe what backend is used and gain other information (which is |
2040 | be used to probe what backend is used and gain other information (which is |
1957 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
2041 | probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and |
1958 | $ENV{PERL_ANYEGENT_STRICT}. |
2042 | $ENV{PERL_ANYEVENT_STRICT}. |
|
|
2043 | |
|
|
2044 | Note that AnyEvent will remove I<all> environment variables starting with |
|
|
2045 | C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is |
|
|
2046 | enabled. |
1959 | |
2047 | |
1960 | |
2048 | |
1961 | =head1 BUGS |
2049 | =head1 BUGS |
1962 | |
2050 | |
1963 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |
2051 | Perl 5.8 has numerous memleaks that sometimes hit this module and are hard |