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2 | |
2 | |
3 | EV - perl interface to libev, a high performance full-featured event loop |
3 | EV - perl interface to libev, a high performance full-featured event loop |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use EV; |
7 | use EV; |
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8 | |
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9 | # TIMERS |
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10 | |
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11 | my $w = EV::timer 2, 0, sub { |
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12 | warn "is called after 2s"; |
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13 | }; |
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14 | |
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15 | my $w = EV::timer 2, 2, sub { |
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16 | warn "is called roughly every 2s (repeat = 2)"; |
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17 | }; |
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18 | |
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19 | undef $w; # destroy event watcher again |
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20 | |
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21 | my $w = EV::periodic 0, 60, 0, sub { |
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22 | warn "is called every minute, on the minute, exactly"; |
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23 | }; |
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24 | |
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25 | # IO |
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26 | |
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27 | my $w = EV::io *STDIN, EV::READ, sub { |
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28 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
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29 | warn "stdin is readable, you entered: ", <STDIN>; |
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30 | }; |
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31 | |
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32 | # SIGNALS |
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33 | |
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34 | my $w = EV::signal 'QUIT', sub { |
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35 | warn "sigquit received\n"; |
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36 | }; |
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37 | |
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38 | # CHILD/PID STATUS CHANGES |
8 | |
39 | |
9 | # TIMERS |
40 | my $w = EV::child 666, 0, sub { |
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41 | my ($w, $revents) = @_; |
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42 | my $status = $w->rstatus; |
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43 | }; |
10 | |
44 | |
11 | my $w = EV::timer 2, 0, sub { |
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12 | warn "is called after 2s"; |
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13 | }; |
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14 | |
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15 | my $w = EV::timer 2, 2, sub { |
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16 | warn "is called roughly every 2s (repeat = 2)"; |
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17 | }; |
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18 | |
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19 | undef $w; # destroy event watcher again |
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20 | |
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21 | my $w = EV::periodic 0, 60, 0, sub { |
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22 | warn "is called every minute, on the minute, exactly"; |
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23 | }; |
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24 | |
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25 | # IO |
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26 | |
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27 | my $w = EV::io *STDIN, EV::READ, sub { |
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28 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
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29 | warn "stdin is readable, you entered: ", <STDIN>; |
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30 | }; |
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31 | |
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32 | # SIGNALS |
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33 | |
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34 | my $w = EV::signal 'QUIT', sub { |
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35 | warn "sigquit received\n"; |
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36 | }; |
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37 | |
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38 | # CHILD/PID STATUS CHANGES |
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39 | |
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40 | my $w = EV::child 666, sub { |
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41 | my ($w, $revents) = @_; |
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42 | my $status = $w->rstatus; |
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43 | }; |
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44 | |
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45 | # STAT CHANGES |
45 | # STAT CHANGES |
46 | my $w = EV::stat "/etc/passwd", 10, sub { |
46 | my $w = EV::stat "/etc/passwd", 10, sub { |
47 | my ($w, $revents) = @_; |
47 | my ($w, $revents) = @_; |
48 | warn $w->path, " has changed somehow.\n"; |
48 | warn $w->path, " has changed somehow.\n"; |
49 | }; |
49 | }; |
50 | |
50 | |
51 | # MAINLOOP |
51 | # MAINLOOP |
52 | EV::loop; # loop until EV::unloop is called or all watchers stop |
52 | EV::loop; # loop until EV::unloop is called or all watchers stop |
53 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
53 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
54 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
54 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
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55 | |
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56 | =head1 BEFORE YOU START USING THIS MODULE |
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57 | |
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58 | If you only need timer, I/O, signal, child and idle watchers and not the |
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59 | advanced functionality of this module, consider using L<AnyEvent> instead, |
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60 | specifically the simplified API described in L<AE>. |
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61 | |
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62 | When used with EV as backend, the L<AE> API is as fast as the native L<EV> |
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63 | API, but your programs/modules will still run with many other event loops. |
55 | |
64 | |
56 | =head1 DESCRIPTION |
65 | =head1 DESCRIPTION |
57 | |
66 | |
58 | This module provides an interface to libev |
67 | This module provides an interface to libev |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
68 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
60 | below is comprehensive, one might also consult the documentation of libev |
69 | below is comprehensive, one might also consult the documentation of |
61 | itself (L<http://cvs.schmorp.de/libev/ev.html>) for more subtle details on |
70 | libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or |
62 | watcher semantics or some discussion on the available backends, or how to |
71 | F<perldoc EV::libev>) for more subtle details on watcher semantics or some |
63 | force a specific backend with C<LIBEV_FLAGS>. |
72 | discussion on the available backends, or how to force a specific backend |
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73 | with C<LIBEV_FLAGS>, or just about in any case because it has much more |
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74 | detailed information. |
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75 | |
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76 | This module is very fast and scalable. It is actually so fast that you |
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77 | can use it through the L<AnyEvent> module, stay portable to other event |
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78 | loops (if you don't rely on any watcher types not available through it) |
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79 | and still be faster than with any other event loop currently supported in |
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80 | Perl. |
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81 | |
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82 | =head2 MODULE EXPORTS |
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83 | |
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84 | This module does not export any symbols. |
64 | |
85 | |
65 | =cut |
86 | =cut |
66 | |
87 | |
67 | package EV; |
88 | package EV; |
68 | |
89 | |
69 | use strict; |
90 | use common::sense; |
70 | |
91 | |
71 | BEGIN { |
92 | BEGIN { |
72 | our $VERSION = '1.4'; |
93 | our $VERSION = '4.00'; |
73 | use XSLoader; |
94 | use XSLoader; |
74 | XSLoader::load "EV", $VERSION; |
95 | XSLoader::load "EV", $VERSION; |
75 | } |
96 | } |
76 | |
97 | |
77 | @EV::IO::ISA = |
98 | @EV::IO::ISA = |
78 | @EV::Timer::ISA = |
99 | @EV::Timer::ISA = |
79 | @EV::Periodic::ISA = |
100 | @EV::Periodic::ISA = |
80 | @EV::Signal::ISA = |
101 | @EV::Signal::ISA = |
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102 | @EV::Child::ISA = |
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103 | @EV::Stat::ISA = |
81 | @EV::Idle::ISA = |
104 | @EV::Idle::ISA = |
82 | @EV::Prepare::ISA = |
105 | @EV::Prepare::ISA = |
83 | @EV::Check::ISA = |
106 | @EV::Check::ISA = |
84 | @EV::Child::ISA = |
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85 | @EV::Embed::ISA = |
107 | @EV::Embed::ISA = |
86 | @EV::Stat::ISA = "EV::Watcher"; |
108 | @EV::Fork::ISA = |
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109 | @EV::Async::ISA = |
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110 | "EV::Watcher"; |
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111 | |
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112 | @EV::Loop::Default::ISA = "EV::Loop"; |
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113 | |
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114 | =head1 EVENT LOOPS |
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115 | |
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116 | EV supports multiple event loops: There is a single "default event loop" |
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117 | that can handle everything including signals and child watchers, and any |
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118 | number of "dynamic event loops" that can use different backends (with |
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119 | various limitations), but no child and signal watchers. |
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120 | |
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121 | You do not have to do anything to create the default event loop: When |
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122 | the module is loaded a suitable backend is selected on the premise of |
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123 | selecting a working backend (which for example rules out kqueue on most |
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124 | BSDs). Modules should, unless they have "special needs" always use the |
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125 | default loop as this is fastest (perl-wise), best supported by other |
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126 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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127 | |
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128 | For specific programs you can create additional event loops dynamically. |
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129 | |
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130 | If you want to take advantage of kqueue (which often works properly for |
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131 | sockets only) even though the default loop doesn't enable it, you can |
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132 | I<embed> a kqueue loop into the default loop: running the default loop |
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133 | will then also service the kqueue loop to some extent. See the example in |
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134 | the section about embed watchers for an example on how to achieve that. |
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135 | |
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136 | =over 4 |
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137 | |
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138 | =item $loop = new EV::Loop [$flags] |
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139 | |
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140 | Create a new event loop as per the specified flags. Please refer to |
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141 | the C<ev_loop_new ()> function description in the libev documentation |
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142 | (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>, |
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143 | or locally-installed as F<EV::libev> manpage) for more info. |
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144 | |
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145 | The loop will automatically be destroyed when it is no longer referenced |
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146 | by any watcher and the loop object goes out of scope. |
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147 | |
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148 | If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK> |
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149 | is recommended, as only the default event loop is protected by this |
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150 | module. If you I<are> embedding this loop in the default loop, this is not |
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151 | necessary, as C<EV::embed> automatically does the right thing on fork. |
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152 | |
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153 | =item $loop->loop_fork |
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154 | |
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155 | Must be called after a fork in the child, before entering or continuing |
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156 | the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls |
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157 | this function automatically, at some performance loss (refer to the libev |
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158 | documentation). |
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159 | |
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160 | =item $loop->loop_verify |
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161 | |
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162 | Calls C<ev_verify> to make internal consistency checks (for debugging |
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163 | libev) and abort the program if any data structures were found to be |
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164 | corrupted. |
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165 | |
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166 | =item $loop = EV::default_loop [$flags] |
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167 | |
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168 | Return the default loop (which is a singleton object). Since this module |
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169 | already creates the default loop with default flags, specifying flags here |
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170 | will not have any effect unless you destroy the default loop first, which |
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171 | isn't supported. So in short: don't do it, and if you break it, you get to |
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172 | keep the pieces. |
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173 | |
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174 | =back |
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175 | |
87 | |
176 | |
88 | =head1 BASIC INTERFACE |
177 | =head1 BASIC INTERFACE |
89 | |
178 | |
90 | =over 4 |
179 | =over 4 |
91 | |
180 | |
92 | =item $EV::DIED |
181 | =item $EV::DIED |
93 | |
182 | |
94 | Must contain a reference to a function that is called when a callback |
183 | Must contain a reference to a function that is called when a callback |
95 | throws an exception (with $@ containing thr error). The default prints an |
184 | throws an exception (with $@ containing the error). The default prints an |
96 | informative message and continues. |
185 | informative message and continues. |
97 | |
186 | |
98 | If this callback throws an exception it will be silently ignored. |
187 | If this callback throws an exception it will be silently ignored. |
99 | |
188 | |
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189 | =item $flags = EV::supported_backends |
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190 | |
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191 | =item $flags = EV::recommended_backends |
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192 | |
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193 | =item $flags = EV::embeddable_backends |
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194 | |
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195 | Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this |
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196 | instance of EV, the set of recommended backends (supposed to be good) for |
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197 | this platform and the set of embeddable backends (see EMBED WATCHERS). |
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198 | |
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199 | =item EV::sleep $seconds |
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200 | |
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201 | Block the process for the given number of (fractional) seconds. |
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202 | |
100 | =item $time = EV::time |
203 | =item $time = EV::time |
101 | |
204 | |
102 | Returns the current time in (fractional) seconds since the epoch. |
205 | Returns the current time in (fractional) seconds since the epoch. |
103 | |
206 | |
104 | =item $time = EV::now |
207 | =item $time = EV::now |
105 | |
208 | |
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209 | =item $time = $loop->now |
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210 | |
106 | Returns the time the last event loop iteration has been started. This |
211 | Returns the time the last event loop iteration has been started. This |
107 | is the time that (relative) timers are based on, and refering to it is |
212 | is the time that (relative) timers are based on, and referring to it is |
108 | usually faster then calling EV::time. |
213 | usually faster then calling EV::time. |
109 | |
214 | |
110 | =item $method = EV::method |
215 | =item EV::now_update |
111 | |
216 | |
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217 | =item $loop->now_update |
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218 | |
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219 | Establishes the current time by querying the kernel, updating the time |
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220 | returned by C<EV::now> in the progress. This is a costly operation and |
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221 | is usually done automatically within C<EV::loop>. |
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222 | |
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223 | This function is rarely useful, but when some event callback runs for a |
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224 | very long time without entering the event loop, updating libev's idea of |
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225 | the current time is a good idea. |
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226 | |
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227 | =item EV::suspend |
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228 | |
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229 | =item $loop->suspend |
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230 | |
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231 | =item EV::resume |
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232 | |
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233 | =item $loop->resume |
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234 | |
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235 | These two functions suspend and resume a loop, for use when the loop is |
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236 | not used for a while and timeouts should not be processed. |
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237 | |
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238 | A typical use case would be an interactive program such as a game: When |
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239 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
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240 | would be best to handle timeouts as if no time had actually passed while |
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241 | the program was suspended. This can be achieved by calling C<suspend> |
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242 | in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling |
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243 | C<resume> directly afterwards to resume timer processing. |
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244 | |
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245 | Effectively, all C<timer> watchers will be delayed by the time spend |
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246 | between C<suspend> and C<resume>, and all C<periodic> watchers |
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247 | will be rescheduled (that is, they will lose any events that would have |
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248 | occured while suspended). |
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249 | |
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250 | After calling C<suspend> you B<must not> call I<any> function on the given |
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251 | loop other than C<resume>, and you B<must not> call C<resume> |
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252 | without a previous call to C<suspend>. |
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253 | |
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254 | Calling C<suspend>/C<resume> has the side effect of updating the event |
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255 | loop time (see C<now_update>). |
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256 | |
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257 | =item $backend = EV::backend |
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258 | |
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259 | =item $backend = $loop->backend |
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260 | |
112 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
261 | Returns an integer describing the backend used by libev (EV::BACKEND_SELECT |
113 | or EV::METHOD_EPOLL). |
262 | or EV::BACKEND_EPOLL). |
114 | |
263 | |
115 | =item EV::loop [$flags] |
264 | =item EV::loop [$flags] |
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265 | |
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266 | =item $loop->loop ([$flags]) |
116 | |
267 | |
117 | Begin checking for events and calling callbacks. It returns when a |
268 | Begin checking for events and calling callbacks. It returns when a |
118 | callback calls EV::unloop. |
269 | callback calls EV::unloop. |
119 | |
270 | |
120 | The $flags argument can be one of the following: |
271 | The $flags argument can be one of the following: |
… | |
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123 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
274 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
124 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
275 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
125 | |
276 | |
126 | =item EV::unloop [$how] |
277 | =item EV::unloop [$how] |
127 | |
278 | |
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279 | =item $loop->unloop ([$how]) |
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280 | |
128 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
281 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
129 | innermost call to EV::loop return. |
282 | innermost call to EV::loop return. |
130 | |
283 | |
131 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
284 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
132 | fast as possible. |
285 | fast as possible. |
133 | |
286 | |
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287 | =item $count = EV::loop_count |
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288 | |
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289 | =item $count = $loop->loop_count |
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290 | |
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291 | Return the number of times the event loop has polled for new |
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292 | events. Sometimes useful as a generation counter. |
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293 | |
134 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
294 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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295 | |
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296 | =item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
135 | |
297 | |
136 | This function rolls together an I/O and a timer watcher for a single |
298 | This function rolls together an I/O and a timer watcher for a single |
137 | one-shot event without the need for managing a watcher object. |
299 | one-shot event without the need for managing a watcher object. |
138 | |
300 | |
139 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
301 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
… | |
… | |
145 | If timeout is C<undef> or negative, then there will be no |
307 | If timeout is C<undef> or negative, then there will be no |
146 | timeout. Otherwise a EV::timer with this value will be started. |
308 | timeout. Otherwise a EV::timer with this value will be started. |
147 | |
309 | |
148 | When an error occurs or either the timeout or I/O watcher triggers, then |
310 | When an error occurs or either the timeout or I/O watcher triggers, then |
149 | the callback will be called with the received event set (in general |
311 | the callback will be called with the received event set (in general |
150 | you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, |
312 | you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, |
151 | C<EV::WRITE> and C<EV::TIMEOUT>). |
313 | C<EV::WRITE> and C<EV::TIMER>). |
152 | |
314 | |
153 | EV::once doesn't return anything: the watchers stay active till either |
315 | EV::once doesn't return anything: the watchers stay active till either |
154 | of them triggers, then they will be stopped and freed, and the callback |
316 | of them triggers, then they will be stopped and freed, and the callback |
155 | invoked. |
317 | invoked. |
156 | |
318 | |
157 | =back |
319 | =item EV::feed_fd_event ($fd, $revents) |
158 | |
320 | |
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321 | =item $loop->feed_fd_event ($fd, $revents) |
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322 | |
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323 | Feed an event on a file descriptor into EV. EV will react to this call as |
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324 | if the readyness notifications specified by C<$revents> (a combination of |
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325 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
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326 | |
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327 | =item EV::feed_signal_event ($signal) |
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328 | |
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329 | Feed a signal event into EV. EV will react to this call as if the signal |
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330 | specified by C<$signal> had occured. |
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331 | |
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332 | =item EV::set_io_collect_interval $time |
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333 | |
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334 | =item $loop->set_io_collect_interval ($time) |
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335 | |
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336 | =item EV::set_timeout_collect_interval $time |
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337 | |
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338 | =item $loop->set_timeout_collect_interval ($time) |
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339 | |
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340 | These advanced functions set the minimum block interval when polling for I/O events and the minimum |
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341 | wait interval for timer events. See the libev documentation at |
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342 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> |
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343 | (locally installed as F<EV::libev>) for a more detailed discussion. |
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344 | |
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345 | =item $count = EV::pending_count |
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346 | |
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347 | =item $count = $loop->pending_count |
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348 | |
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349 | Returns the number of currently pending watchers. |
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350 | |
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351 | =item EV::invoke_pending |
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352 | |
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353 | =item $loop->invoke_pending |
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354 | |
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355 | Invoke all currently pending watchers. |
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356 | |
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357 | =back |
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358 | |
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359 | |
159 | =head2 WATCHER OBJECTS |
360 | =head1 WATCHER OBJECTS |
160 | |
361 | |
161 | A watcher is an object that gets created to record your interest in some |
362 | A watcher is an object that gets created to record your interest in some |
162 | event. For instance, if you want to wait for STDIN to become readable, you |
363 | event. For instance, if you want to wait for STDIN to become readable, you |
163 | would create an EV::io watcher for that: |
364 | would create an EV::io watcher for that: |
164 | |
365 | |
165 | my $watcher = EV::io *STDIN, EV::READ, sub { |
366 | my $watcher = EV::io *STDIN, EV::READ, sub { |
166 | my ($watcher, $revents) = @_; |
367 | my ($watcher, $revents) = @_; |
167 | warn "yeah, STDIN should not be readable without blocking!\n" |
368 | warn "yeah, STDIN should now be readable without blocking!\n" |
168 | }; |
369 | }; |
169 | |
370 | |
170 | All watchers can be active (waiting for events) or inactive (paused). Only |
371 | All watchers can be active (waiting for events) or inactive (paused). Only |
171 | active watchers will have their callbacks invoked. All callbacks will be |
372 | active watchers will have their callbacks invoked. All callbacks will be |
172 | called with at least two arguments: the watcher and a bitmask of received |
373 | called with at least two arguments: the watcher and a bitmask of received |
173 | events. |
374 | events. |
174 | |
375 | |
175 | Each watcher type has its associated bit in revents, so you can use the |
376 | Each watcher type has its associated bit in revents, so you can use the |
176 | same callback for multiple watchers. The event mask is named after the |
377 | same callback for multiple watchers. The event mask is named after the |
177 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
378 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
178 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
379 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
179 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
380 | (which can set both EV::READ and EV::WRITE bits). |
180 | uses EV::TIMEOUT). |
|
|
181 | |
381 | |
182 | In the rare case where one wants to create a watcher but not start it at |
382 | In the rare case where one wants to create a watcher but not start it at |
183 | the same time, each constructor has a variant with a trailing C<_ns> in |
383 | the same time, each constructor has a variant with a trailing C<_ns> in |
184 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
384 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
185 | |
385 | |
… | |
… | |
205 | |
405 | |
206 | =item $w->stop |
406 | =item $w->stop |
207 | |
407 | |
208 | Stop a watcher if it is active. Also clear any pending events (events that |
408 | Stop a watcher if it is active. Also clear any pending events (events that |
209 | have been received but that didn't yet result in a callback invocation), |
409 | have been received but that didn't yet result in a callback invocation), |
210 | regardless of wether the watcher was active or not. |
410 | regardless of whether the watcher was active or not. |
211 | |
411 | |
212 | =item $bool = $w->is_active |
412 | =item $bool = $w->is_active |
213 | |
413 | |
214 | Returns true if the watcher is active, false otherwise. |
414 | Returns true if the watcher is active, false otherwise. |
215 | |
415 | |
… | |
… | |
245 | The default priority of any newly-created watcher is 0. |
445 | The default priority of any newly-created watcher is 0. |
246 | |
446 | |
247 | Note that the priority semantics have not yet been fleshed out and are |
447 | Note that the priority semantics have not yet been fleshed out and are |
248 | subject to almost certain change. |
448 | subject to almost certain change. |
249 | |
449 | |
250 | =item $w->trigger ($revents) |
450 | =item $w->invoke ($revents) |
251 | |
451 | |
252 | Call the callback *now* with the given event mask. |
452 | Call the callback *now* with the given event mask. |
|
|
453 | |
|
|
454 | =item $w->feed_event ($revents) |
|
|
455 | |
|
|
456 | Feed some events on this watcher into EV. EV will react to this call as if |
|
|
457 | the watcher had received the given C<$revents> mask. |
|
|
458 | |
|
|
459 | =item $revents = $w->clear_pending |
|
|
460 | |
|
|
461 | If the watcher is pending, this function clears its pending status and |
|
|
462 | returns its C<$revents> bitset (as if its callback was invoked). If the |
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|
463 | watcher isn't pending it does nothing and returns C<0>. |
253 | |
464 | |
254 | =item $previous_state = $w->keepalive ($bool) |
465 | =item $previous_state = $w->keepalive ($bool) |
255 | |
466 | |
256 | Normally, C<EV::loop> will return when there are no active watchers |
467 | Normally, C<EV::loop> will return when there are no active watchers |
257 | (which is a "deadlock" because no progress can be made anymore). This is |
468 | (which is a "deadlock" because no progress can be made anymore). This is |
258 | convinient because it allows you to start your watchers (and your jobs), |
469 | convenient because it allows you to start your watchers (and your jobs), |
259 | call C<EV::loop> once and when it returns you know that all your jobs are |
470 | call C<EV::loop> once and when it returns you know that all your jobs are |
260 | finished (or they forgot to register some watchers for their task :). |
471 | finished (or they forgot to register some watchers for their task :). |
261 | |
472 | |
262 | Sometimes, however, this gets in your way, for example when you the module |
473 | Sometimes, however, this gets in your way, for example when the module |
263 | that calls C<EV::loop> (usually the main program) is not the same module |
474 | that calls C<EV::loop> (usually the main program) is not the same module |
264 | as a long-living watcher (for example a DNS client module written by |
475 | as a long-living watcher (for example a DNS client module written by |
265 | somebody else even). Then you might want any outstanding requests to be |
476 | somebody else even). Then you might want any outstanding requests to be |
266 | handled, but you would not want to keep C<EV::loop> from returning just |
477 | handled, but you would not want to keep C<EV::loop> from returning just |
267 | because you happen to have this long-running UDP port watcher. |
478 | because you happen to have this long-running UDP port watcher. |
268 | |
479 | |
269 | In this case you can clear the keepalive status, which means that even |
480 | In this case you can clear the keepalive status, which means that even |
270 | though your watcher is active, it won't keep C<EV::loop> from returning. |
481 | though your watcher is active, it won't keep C<EV::loop> from returning. |
271 | |
482 | |
272 | The initial value for keepalive is true (enabled), and you cna change it |
483 | The initial value for keepalive is true (enabled), and you can change it |
273 | any time. |
484 | any time. |
274 | |
485 | |
275 | Example: Register an IO watcher for some UDP socket but do not keep the |
486 | Example: Register an I/O watcher for some UDP socket but do not keep the |
276 | event loop from running just because of that watcher. |
487 | event loop from running just because of that watcher. |
277 | |
488 | |
278 | my $udp_socket = ... |
489 | my $udp_socket = ... |
279 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
490 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
280 | $udp_watcher->keepalive (0); |
491 | $udp_watcher->keepalive (0); |
281 | |
492 | |
282 | =back |
493 | =item $loop = $w->loop |
283 | |
494 | |
|
|
495 | Return the loop that this watcher is attached to. |
284 | |
496 | |
|
|
497 | =back |
|
|
498 | |
|
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499 | |
285 | =head2 WATCHER TYPES |
500 | =head1 WATCHER TYPES |
286 | |
501 | |
287 | Each of the following subsections describes a single watcher type. |
502 | Each of the following subsections describes a single watcher type. |
288 | |
503 | |
289 | =head3 IO WATCHERS - is this file descriptor readable or writable? |
504 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
290 | |
505 | |
291 | =over 4 |
506 | =over 4 |
292 | |
507 | |
293 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
508 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
294 | |
509 | |
295 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
510 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
|
|
511 | |
|
|
512 | =item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
513 | |
|
|
514 | =item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
296 | |
515 | |
297 | As long as the returned watcher object is alive, call the C<$callback> |
516 | As long as the returned watcher object is alive, call the C<$callback> |
298 | when at least one of events specified in C<$eventmask> occurs. |
517 | when at least one of events specified in C<$eventmask> occurs. |
299 | |
518 | |
300 | The $eventmask can be one or more of these constants ORed together: |
519 | The $eventmask can be one or more of these constants ORed together: |
… | |
… | |
329 | =over 4 |
548 | =over 4 |
330 | |
549 | |
331 | =item $w = EV::timer $after, $repeat, $callback |
550 | =item $w = EV::timer $after, $repeat, $callback |
332 | |
551 | |
333 | =item $w = EV::timer_ns $after, $repeat, $callback |
552 | =item $w = EV::timer_ns $after, $repeat, $callback |
|
|
553 | |
|
|
554 | =item $w = $loop->timer ($after, $repeat, $callback) |
|
|
555 | |
|
|
556 | =item $w = $loop->timer_ns ($after, $repeat, $callback) |
334 | |
557 | |
335 | Calls the callback after C<$after> seconds (which may be fractional). If |
558 | Calls the callback after C<$after> seconds (which may be fractional). If |
336 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
559 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
337 | value as $after) after the callback returns. |
560 | value as $after) after the callback returns. |
338 | |
561 | |
… | |
… | |
379 | =over 4 |
602 | =over 4 |
380 | |
603 | |
381 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
604 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
382 | |
605 | |
383 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
606 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
|
|
607 | |
|
|
608 | =item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
|
|
609 | |
|
|
610 | =item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
384 | |
611 | |
385 | Similar to EV::timer, but is not based on relative timeouts but on |
612 | Similar to EV::timer, but is not based on relative timeouts but on |
386 | absolute times. Apart from creating "simple" timers that trigger "at" the |
613 | absolute times. Apart from creating "simple" timers that trigger "at" the |
387 | specified time, it can also be used for non-drifting absolute timers and |
614 | specified time, it can also be used for non-drifting absolute timers and |
388 | more complex, cron-like, setups that are not adversely affected by time |
615 | more complex, cron-like, setups that are not adversely affected by time |
… | |
… | |
398 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
625 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
399 | will not adjust when a time jump occurs, that is, if it is to be run |
626 | will not adjust when a time jump occurs, that is, if it is to be run |
400 | at January 1st 2011 then it will run when the system time reaches or |
627 | at January 1st 2011 then it will run when the system time reaches or |
401 | surpasses this time. |
628 | surpasses this time. |
402 | |
629 | |
403 | =item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
630 | =item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
404 | |
631 | |
405 | In this mode the watcher will always be scheduled to time out at the |
632 | In this mode the watcher will always be scheduled to time out at the |
406 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
633 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
407 | regardless of any time jumps. |
634 | regardless of any time jumps. |
408 | |
635 | |
… | |
… | |
426 | time the periodic watcher gets scheduled, the reschedule callback |
653 | time the periodic watcher gets scheduled, the reschedule callback |
427 | ($reschedule_cb) will be called with the watcher as first, and the current |
654 | ($reschedule_cb) will be called with the watcher as first, and the current |
428 | time as second argument. |
655 | time as second argument. |
429 | |
656 | |
430 | I<This callback MUST NOT stop or destroy this or any other periodic |
657 | I<This callback MUST NOT stop or destroy this or any other periodic |
431 | watcher, ever>. If you need to stop it, return 1e30 and stop it |
658 | watcher, ever, and MUST NOT call any event loop functions or methods>. If |
432 | afterwards. |
659 | you need to stop it, return 1e30 and stop it afterwards. You may create |
|
|
660 | and start a C<EV::prepare> watcher for this task. |
433 | |
661 | |
434 | It must return the next time to trigger, based on the passed time value |
662 | It must return the next time to trigger, based on the passed time value |
435 | (that is, the lowest time value larger than to the second argument). It |
663 | (that is, the lowest time value larger than or equal to to the second |
436 | will usually be called just before the callback will be triggered, but |
664 | argument). It will usually be called just before the callback will be |
437 | might be called at other times, too. |
665 | triggered, but might be called at other times, too. |
438 | |
666 | |
439 | This can be used to create very complex timers, such as a timer that |
667 | This can be used to create very complex timers, such as a timer that |
440 | triggers on each midnight, local time (actually 24 hours after the last |
668 | triggers on each midnight, local time (actually 24 hours after the last |
441 | midnight, to keep the example simple. If you know a way to do it correctly |
669 | midnight, to keep the example simple. If you know a way to do it correctly |
442 | in about the same space (without requiring elaborate modules), drop me a |
670 | in about the same space (without requiring elaborate modules), drop me a |
… | |
… | |
463 | |
691 | |
464 | =item $w->again |
692 | =item $w->again |
465 | |
693 | |
466 | Simply stops and starts the watcher again. |
694 | Simply stops and starts the watcher again. |
467 | |
695 | |
|
|
696 | =item $time = $w->at |
|
|
697 | |
|
|
698 | Return the time that the watcher is expected to trigger next. |
|
|
699 | |
468 | =back |
700 | =back |
469 | |
701 | |
470 | |
702 | |
471 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
703 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
472 | |
704 | |
473 | =over 4 |
705 | =over 4 |
474 | |
706 | |
475 | =item $w = EV::signal $signal, $callback |
707 | =item $w = EV::signal $signal, $callback |
476 | |
708 | |
477 | =item $w = EV::signal_ns $signal, $callback |
709 | =item $w = EV::signal_ns $signal, $callback |
|
|
710 | |
|
|
711 | =item $w = $loop->signal ($signal, $callback) |
|
|
712 | |
|
|
713 | =item $w = $loop->signal_ns ($signal, $callback) |
478 | |
714 | |
479 | Call the callback when $signal is received (the signal can be specified by |
715 | Call the callback when $signal is received (the signal can be specified by |
480 | number or by name, just as with C<kill> or C<%SIG>). |
716 | number or by name, just as with C<kill> or C<%SIG>). |
|
|
717 | |
|
|
718 | Only one event loop can grab a given signal - attempting to grab the same |
|
|
719 | signal from two EV loops will crash the program immediately or cause data |
|
|
720 | corruption. |
481 | |
721 | |
482 | EV will grab the signal for the process (the kernel only allows one |
722 | EV will grab the signal for the process (the kernel only allows one |
483 | component to receive a signal at a time) when you start a signal watcher, |
723 | component to receive a signal at a time) when you start a signal watcher, |
484 | and removes it again when you stop it. Perl does the same when you |
724 | and removes it again when you stop it. Perl does the same when you |
485 | add/remove callbacks to C<%SIG>, so watch out. |
725 | add/remove callbacks to C<%SIG>, so watch out. |
… | |
… | |
505 | |
745 | |
506 | =head3 CHILD WATCHERS - watch out for process status changes |
746 | =head3 CHILD WATCHERS - watch out for process status changes |
507 | |
747 | |
508 | =over 4 |
748 | =over 4 |
509 | |
749 | |
510 | =item $w = EV::child $pid, $callback |
750 | =item $w = EV::child $pid, $trace, $callback |
511 | |
751 | |
512 | =item $w = EV::child_ns $pid, $callback |
752 | =item $w = EV::child_ns $pid, $trace, $callback |
513 | |
753 | |
|
|
754 | =item $w = $loop->child ($pid, $trace, $callback) |
|
|
755 | |
|
|
756 | =item $w = $loop->child_ns ($pid, $trace, $callback) |
|
|
757 | |
514 | Call the callback when a status change for pid C<$pid> (or any pid if |
758 | Call the callback when a status change for pid C<$pid> (or any pid |
515 | C<$pid> is 0) has been received. More precisely: when the process receives |
759 | if C<$pid> is 0) has been received (a status change happens when the |
|
|
760 | process terminates or is killed, or, when trace is true, additionally when |
|
|
761 | it is stopped or continued). More precisely: when the process receives |
516 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
762 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
517 | changed/zombie children and call the callback. |
763 | changed/zombie children and call the callback. |
518 | |
764 | |
519 | It is valid (and fully supported) to install a child watcher after a child |
765 | It is valid (and fully supported) to install a child watcher after a child |
520 | has exited but before the event loop has started its next iteration (for |
766 | has exited but before the event loop has started its next iteration (for |
… | |
… | |
527 | You can have as many pid watchers per pid as you want, they will all be |
773 | You can have as many pid watchers per pid as you want, they will all be |
528 | called. |
774 | called. |
529 | |
775 | |
530 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
776 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
531 | |
777 | |
532 | =item $w->set ($pid) |
778 | =item $w->set ($pid, $trace) |
533 | |
779 | |
534 | Reconfigures the watcher, see the constructor above for details. Can be called at |
780 | Reconfigures the watcher, see the constructor above for details. Can be called at |
535 | any time. |
781 | any time. |
536 | |
782 | |
537 | =item $current_pid = $w->pid |
783 | =item $current_pid = $w->pid |
538 | |
784 | |
539 | =item $old_pid = $w->pid ($new_pid) |
|
|
540 | |
|
|
541 | Returns the previously set process id and optionally set a new one. |
785 | Returns the previously set process id and optionally set a new one. |
542 | |
786 | |
543 | =item $exit_status = $w->rstatus |
787 | =item $exit_status = $w->rstatus |
544 | |
788 | |
545 | Return the exit/wait status (as returned by waitpid, see the waitpid entry |
789 | Return the exit/wait status (as returned by waitpid, see the waitpid entry |
… | |
… | |
551 | watcher for all pids). |
795 | watcher for all pids). |
552 | |
796 | |
553 | =back |
797 | =back |
554 | |
798 | |
555 | |
799 | |
|
|
800 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
801 | |
|
|
802 | =over 4 |
|
|
803 | |
|
|
804 | =item $w = EV::stat $path, $interval, $callback |
|
|
805 | |
|
|
806 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
807 | |
|
|
808 | =item $w = $loop->stat ($path, $interval, $callback) |
|
|
809 | |
|
|
810 | =item $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
811 | |
|
|
812 | Call the callback when a file status change has been detected on |
|
|
813 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
814 | to "path does not exist" is a status change like any other. |
|
|
815 | |
|
|
816 | The C<$interval> is a recommended polling interval for systems where |
|
|
817 | OS-supported change notifications don't exist or are not supported. If |
|
|
818 | you use C<0> then an unspecified default is used (which is highly |
|
|
819 | recommended!), which is to be expected to be around five seconds usually. |
|
|
820 | |
|
|
821 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
822 | as even with OS-supported change notifications, this can be |
|
|
823 | resource-intensive. |
|
|
824 | |
|
|
825 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
826 | |
|
|
827 | =item ... = $w->stat |
|
|
828 | |
|
|
829 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
830 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
831 | well as EV's idea of the current stat values) to the values found. |
|
|
832 | |
|
|
833 | In scalar context, a boolean is return indicating success or failure of |
|
|
834 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
835 | (except that the blksize and blocks fields are not reliable). |
|
|
836 | |
|
|
837 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
838 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
839 | was successful then nlink is guaranteed to be non-zero). |
|
|
840 | |
|
|
841 | See also the next two entries for more info. |
|
|
842 | |
|
|
843 | =item ... = $w->attr |
|
|
844 | |
|
|
845 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
846 | the values most recently detected by EV. See the next entry for more info. |
|
|
847 | |
|
|
848 | =item ... = $w->prev |
|
|
849 | |
|
|
850 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
851 | the previous set of values, before the change. |
|
|
852 | |
|
|
853 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
854 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
855 | returns the values found leading to the change detection. The difference (if any) |
|
|
856 | between C<prev> and C<attr> is what triggered the callback. |
|
|
857 | |
|
|
858 | If you did something to the filesystem object and do not want to trigger |
|
|
859 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
860 | current attributes are. |
|
|
861 | |
|
|
862 | =item $w->set ($path, $interval) |
|
|
863 | |
|
|
864 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
865 | called at any time. |
|
|
866 | |
|
|
867 | =item $current_path = $w->path |
|
|
868 | |
|
|
869 | =item $old_path = $w->path ($new_path) |
|
|
870 | |
|
|
871 | Returns the previously set path and optionally set a new one. |
|
|
872 | |
|
|
873 | =item $current_interval = $w->interval |
|
|
874 | |
|
|
875 | =item $old_interval = $w->interval ($new_interval) |
|
|
876 | |
|
|
877 | Returns the previously set interval and optionally set a new one. Can be |
|
|
878 | used to query the actual interval used. |
|
|
879 | |
|
|
880 | =back |
|
|
881 | |
|
|
882 | |
556 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
883 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
557 | |
884 | |
558 | =over 4 |
885 | =over 4 |
559 | |
886 | |
560 | =item $w = EV::idle $callback |
887 | =item $w = EV::idle $callback |
561 | |
888 | |
562 | =item $w = EV::idle_ns $callback |
889 | =item $w = EV::idle_ns $callback |
563 | |
890 | |
564 | Call the callback when there are no pending io, timer/periodic, signal or |
891 | =item $w = $loop->idle ($callback) |
565 | child events, i.e. when the process is idle. |
892 | |
|
|
893 | =item $w = $loop->idle_ns ($callback) |
|
|
894 | |
|
|
895 | Call the callback when there are no other pending watchers of the same or |
|
|
896 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
897 | same or lower priority, of course). They are called idle watchers because |
|
|
898 | when the watcher is the highest priority pending event in the process, the |
|
|
899 | process is considered to be idle at that priority. |
|
|
900 | |
|
|
901 | If you want a watcher that is only ever called when I<no> other events are |
|
|
902 | outstanding you have to set the priority to C<EV::MINPRI>. |
566 | |
903 | |
567 | The process will not block as long as any idle watchers are active, and |
904 | The process will not block as long as any idle watchers are active, and |
568 | they will be called repeatedly until stopped. |
905 | they will be called repeatedly until stopped. |
569 | |
906 | |
|
|
907 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
908 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
909 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
910 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
911 | pending with the C<0>-priority idle watcher be invoked. |
|
|
912 | |
570 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
913 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
571 | |
914 | |
572 | =back |
915 | =back |
573 | |
916 | |
574 | |
917 | |
… | |
… | |
577 | =over 4 |
920 | =over 4 |
578 | |
921 | |
579 | =item $w = EV::prepare $callback |
922 | =item $w = EV::prepare $callback |
580 | |
923 | |
581 | =item $w = EV::prepare_ns $callback |
924 | =item $w = EV::prepare_ns $callback |
|
|
925 | |
|
|
926 | =item $w = $loop->prepare ($callback) |
|
|
927 | |
|
|
928 | =item $w = $loop->prepare_ns ($callback) |
582 | |
929 | |
583 | Call the callback just before the process would block. You can still |
930 | Call the callback just before the process would block. You can still |
584 | create/modify any watchers at this point. |
931 | create/modify any watchers at this point. |
585 | |
932 | |
586 | See the EV::check watcher, below, for explanations and an example. |
933 | See the EV::check watcher, below, for explanations and an example. |
… | |
… | |
595 | =over 4 |
942 | =over 4 |
596 | |
943 | |
597 | =item $w = EV::check $callback |
944 | =item $w = EV::check $callback |
598 | |
945 | |
599 | =item $w = EV::check_ns $callback |
946 | =item $w = EV::check_ns $callback |
|
|
947 | |
|
|
948 | =item $w = $loop->check ($callback) |
|
|
949 | |
|
|
950 | =item $w = $loop->check_ns ($callback) |
600 | |
951 | |
601 | Call the callback just after the process wakes up again (after it has |
952 | Call the callback just after the process wakes up again (after it has |
602 | gathered events), but before any other callbacks have been invoked. |
953 | gathered events), but before any other callbacks have been invoked. |
603 | |
954 | |
604 | This is used to integrate other event-based software into the EV |
955 | This is used to integrate other event-based software into the EV |
… | |
… | |
614 | or return; |
965 | or return; |
615 | |
966 | |
616 | # make the dispatcher handle any outstanding stuff |
967 | # make the dispatcher handle any outstanding stuff |
617 | ... not shown |
968 | ... not shown |
618 | |
969 | |
619 | # create an IO watcher for each and every socket |
970 | # create an I/O watcher for each and every socket |
620 | @snmp_watcher = ( |
971 | @snmp_watcher = ( |
621 | (map { EV::io $_, EV::READ, sub { } } |
972 | (map { EV::io $_, EV::READ, sub { } } |
622 | keys %{ $dispatcher->{_descriptors} }), |
973 | keys %{ $dispatcher->{_descriptors} }), |
623 | |
974 | |
624 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
975 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
… | |
… | |
639 | # make the dispatcher handle any new stuff |
990 | # make the dispatcher handle any new stuff |
640 | ... not shown |
991 | ... not shown |
641 | }; |
992 | }; |
642 | |
993 | |
643 | The callbacks of the created watchers will not be called as the watchers |
994 | The callbacks of the created watchers will not be called as the watchers |
644 | are destroyed before this cna happen (remember EV::check gets called |
995 | are destroyed before this can happen (remember EV::check gets called |
645 | first). |
996 | first). |
646 | |
997 | |
647 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
998 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
648 | |
999 | |
649 | =back |
1000 | =back |
650 | |
1001 | |
651 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
652 | |
1002 | |
653 | =over 4 |
1003 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
654 | |
1004 | |
655 | =item $w = EV::stat $path, $interval, $callback |
1005 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
1006 | is done before the event loop blocks next and before C<check> watchers |
|
|
1007 | are being called, and only in the child after the fork. |
656 | |
1008 | |
657 | =item $w = EV::stat_ns $path, $interval, $callback |
1009 | =over 4 |
658 | |
1010 | |
659 | Call the callback when a file status change has been detected on |
1011 | =item $w = EV::fork $callback |
660 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
661 | to "path does not exist" is a status change like any other. |
|
|
662 | |
1012 | |
663 | The C<$interval> is a recommended polling interval for systems where |
1013 | =item $w = EV::fork_ns $callback |
664 | OS-supported change notifications don't exist or are not supported. If |
|
|
665 | you use C<0> then an unspecified default is used (which is highly |
|
|
666 | recommended!), which is to be expected to be around five seconds usually. |
|
|
667 | |
1014 | |
668 | This watcher type is not meant for massive numbers of stat watchers, |
1015 | =item $w = $loop->fork ($callback) |
669 | as even with OS-supported change notifications, this can be |
|
|
670 | resource-intensive. |
|
|
671 | |
1016 | |
|
|
1017 | =item $w = $loop->fork_ns ($callback) |
|
|
1018 | |
|
|
1019 | Call the callback before the event loop is resumed in the child process |
|
|
1020 | after a fork. |
|
|
1021 | |
672 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
1022 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
673 | |
1023 | |
674 | =item $w->set ($path, $interval) |
|
|
675 | |
|
|
676 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
677 | called at any time. |
|
|
678 | |
|
|
679 | =item $current_path = $w->path |
|
|
680 | |
|
|
681 | =item $old_path = $w->path ($new_path) |
|
|
682 | |
|
|
683 | Returns the previously set path and optionally set a new one. |
|
|
684 | |
|
|
685 | =item $current_interval = $w->interval |
|
|
686 | |
|
|
687 | =item $old_interval = $w->interval ($new_interval) |
|
|
688 | |
|
|
689 | Returns the previously set interval and optionally set a new one. Can be |
|
|
690 | used to query the actual interval used. |
|
|
691 | |
|
|
692 | =back |
1024 | =back |
693 | |
1025 | |
694 | |
1026 | |
|
|
1027 | =head3 EMBED WATCHERS - when one backend isn't enough... |
|
|
1028 | |
|
|
1029 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1030 | into another (currently only IO events are supported in the embedded |
|
|
1031 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1032 | fashion and must not be used). |
|
|
1033 | |
|
|
1034 | See the libev documentation at |
|
|
1035 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> |
|
|
1036 | (locally installed as F<EV::libev>) for more details. |
|
|
1037 | |
|
|
1038 | In short, this watcher is most useful on BSD systems without working |
|
|
1039 | kqueue to still be able to handle a large number of sockets: |
|
|
1040 | |
|
|
1041 | my $socket_loop; |
|
|
1042 | |
|
|
1043 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
1044 | if ( |
|
|
1045 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
1046 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
1047 | ) { |
|
|
1048 | # use kqueue for sockets |
|
|
1049 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
1050 | } |
|
|
1051 | |
|
|
1052 | # use the default loop otherwise |
|
|
1053 | $socket_loop ||= EV::default_loop; |
|
|
1054 | |
|
|
1055 | =over 4 |
|
|
1056 | |
|
|
1057 | =item $w = EV::embed $otherloop[, $callback] |
|
|
1058 | |
|
|
1059 | =item $w = EV::embed_ns $otherloop[, $callback] |
|
|
1060 | |
|
|
1061 | =item $w = $loop->embed ($otherloop[, $callback]) |
|
|
1062 | |
|
|
1063 | =item $w = $loop->embed_ns ($otherloop[, $callback]) |
|
|
1064 | |
|
|
1065 | Call the callback when the embedded event loop (C<$otherloop>) has any |
|
|
1066 | I/O activity. The C<$callback> is optional: if it is missing, then the |
|
|
1067 | embedded event loop will be managed automatically (which is recommended), |
|
|
1068 | otherwise you have to invoke C<sweep> yourself. |
|
|
1069 | |
|
|
1070 | The C<embed_ns> variant doesn't start (activate) the newly created watcher. |
|
|
1071 | |
|
|
1072 | =back |
|
|
1073 | |
|
|
1074 | =head3 ASYNC WATCHERS - how to wake up another event loop |
|
|
1075 | |
|
|
1076 | Async watchers are provided by EV, but have little use in perl directly, |
|
|
1077 | as perl neither supports threads running in parallel nor direct access to |
|
|
1078 | signal handlers or other contexts where they could be of value. |
|
|
1079 | |
|
|
1080 | It is, however, possible to use them from the XS level. |
|
|
1081 | |
|
|
1082 | Please see the libev documentation for further details. |
|
|
1083 | |
|
|
1084 | =over 4 |
|
|
1085 | |
|
|
1086 | =item $w = EV::async $callback |
|
|
1087 | |
|
|
1088 | =item $w = EV::async_ns $callback |
|
|
1089 | |
|
|
1090 | =item $w->send |
|
|
1091 | |
|
|
1092 | =item $bool = $w->async_pending |
|
|
1093 | |
|
|
1094 | =back |
|
|
1095 | |
|
|
1096 | |
|
|
1097 | =head1 PERL SIGNALS |
|
|
1098 | |
|
|
1099 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
1100 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
1101 | handled when Perl runs, which means your signal handler might be invoked |
|
|
1102 | only the next time an event callback is invoked. |
|
|
1103 | |
|
|
1104 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
1105 | ensure proper operations with regards to other event watchers. |
|
|
1106 | |
|
|
1107 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
1108 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
1109 | watcher: |
|
|
1110 | |
|
|
1111 | my $async_check = EV::check sub { }; |
|
|
1112 | |
|
|
1113 | This ensures that perl gets into control for a short time to handle any |
|
|
1114 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
1115 | |
695 | =head1 THREADS |
1116 | =head1 ITHREADS |
696 | |
1117 | |
697 | Threads are not supported by this module in any way. Perl pseudo-threads |
1118 | Ithreads are not supported by this module in any way. Perl pseudo-threads |
698 | is evil stuff and must die. As soon as Perl gains real threads I will work |
1119 | is evil stuff and must die. Real threads as provided by Coro are fully |
699 | on thread support for it. |
1120 | supported (and enhanced support is available via L<Coro::EV>). |
700 | |
1121 | |
701 | =head1 FORK |
1122 | =head1 FORK |
702 | |
1123 | |
703 | Most of the "improved" event delivering mechanisms of modern operating |
1124 | Most of the "improved" event delivering mechanisms of modern operating |
704 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
1125 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
… | |
… | |
720 | our $DIED = sub { |
1141 | our $DIED = sub { |
721 | warn "EV: error in callback (ignoring): $@"; |
1142 | warn "EV: error in callback (ignoring): $@"; |
722 | }; |
1143 | }; |
723 | |
1144 | |
724 | default_loop |
1145 | default_loop |
725 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
1146 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
726 | |
1147 | |
727 | 1; |
1148 | 1; |
728 | |
1149 | |
729 | =head1 SEE ALSO |
1150 | =head1 SEE ALSO |
730 | |
1151 | |
731 | L<EV::DNS>. |
1152 | L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
1153 | event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient |
|
|
1154 | coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for |
|
|
1155 | event-loop agnostic and portable event driven programming. |
732 | |
1156 | |
733 | =head1 AUTHOR |
1157 | =head1 AUTHOR |
734 | |
1158 | |
735 | Marc Lehmann <schmorp@schmorp.de> |
1159 | Marc Lehmann <schmorp@schmorp.de> |
736 | http://home.schmorp.de/ |
1160 | http://home.schmorp.de/ |
737 | |
1161 | |
738 | =cut |
1162 | =cut |
739 | |
1163 | |