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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 { |
45 | # STAT CHANGES |
12 | warn "is called after 2s"; |
46 | my $w = EV::stat "/etc/passwd", 10, sub { |
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47 | my ($w, $revents) = @_; |
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48 | warn $w->path, " has changed somehow.\n"; |
13 | }; |
49 | }; |
14 | |
50 | |
15 | my $w = EV::timer 2, 1, sub { |
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16 | warn "is called roughly every 2s (repeat = 1)"; |
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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, 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 get the watcher object 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 | my $w = EV::signal 3, sub { |
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39 | warn "sigquit received (this is GNU/Linux, right?)\n"; |
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40 | }; |
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41 | |
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42 | # CHILD/PID STATUS CHANGES |
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43 | |
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44 | my $w = EV::child 666, sub { |
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45 | my ($w, $revents, $status) = @_; |
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46 | }; |
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47 | |
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48 | # MAINLOOP |
51 | # MAINLOOP |
49 | EV::loop; # loop until EV::loop_done is called |
52 | EV::loop; # loop until EV::unloop is called or all watchers stop |
50 | 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 |
51 | 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 |
52 | |
55 | |
53 | =head1 DESCRIPTION |
56 | =head1 DESCRIPTION |
54 | |
57 | |
55 | This module provides an interface to libev |
58 | This module provides an interface to libev |
56 | (L<http://software.schmorp.de/pkg/libev.html>). |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
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60 | below is comprehensive, one might also consult the documentation of |
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61 | libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or |
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62 | F<perldoc EV::libev>) for more subtle details on watcher semantics or some |
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63 | discussion on the available backends, or how to force a specific backend |
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64 | with C<LIBEV_FLAGS>, or just about in any case because it has much more |
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65 | detailed information. |
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66 | |
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67 | This module is very fast and scalable. It is actually so fast that you |
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68 | can use it through the L<AnyEvent> module, stay portable to other event |
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69 | loops (if you don't rely on any watcher types not available through it) |
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70 | and still be faster than with any other event loop currently supported in |
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71 | Perl. |
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72 | |
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73 | =head2 MODULE EXPORTS |
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74 | |
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75 | This module does not export any symbols. |
57 | |
76 | |
58 | =cut |
77 | =cut |
59 | |
78 | |
60 | package EV; |
79 | package EV; |
61 | |
80 | |
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81 | no warnings; |
62 | use strict; |
82 | use strict; |
63 | |
83 | |
64 | BEGIN { |
84 | BEGIN { |
65 | our $VERSION = '0.1'; |
85 | our $VERSION = '3.53'; |
66 | use XSLoader; |
86 | use XSLoader; |
67 | XSLoader::load "EV", $VERSION; |
87 | XSLoader::load "EV", $VERSION; |
68 | } |
88 | } |
69 | |
89 | |
70 | @EV::Io::ISA = |
90 | @EV::IO::ISA = |
71 | @EV::Timer::ISA = |
91 | @EV::Timer::ISA = |
72 | @EV::Periodic::ISA = |
92 | @EV::Periodic::ISA = |
73 | @EV::Signal::ISA = |
93 | @EV::Signal::ISA = |
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94 | @EV::Child::ISA = |
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95 | @EV::Stat::ISA = |
74 | @EV::Idle::ISA = |
96 | @EV::Idle::ISA = |
75 | @EV::Prepare::ISA = |
97 | @EV::Prepare::ISA = |
76 | @EV::Check::ISA = |
98 | @EV::Check::ISA = |
77 | @EV::Child::ISA = "EV::Watcher"; |
99 | @EV::Embed::ISA = |
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100 | @EV::Fork::ISA = |
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101 | @EV::Async::ISA = |
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102 | "EV::Watcher"; |
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103 | |
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104 | @EV::Loop::Default::ISA = "EV::Loop"; |
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105 | |
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106 | =head1 EVENT LOOPS |
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107 | |
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108 | EV supports multiple event loops: There is a single "default event loop" |
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109 | that can handle everything including signals and child watchers, and any |
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110 | number of "dynamic event loops" that can use different backends (with |
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111 | various limitations), but no child and signal watchers. |
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112 | |
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113 | You do not have to do anything to create the default event loop: When |
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114 | the module is loaded a suitable backend is selected on the premise of |
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115 | selecting a working backend (which for example rules out kqueue on most |
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116 | BSDs). Modules should, unless they have "special needs" always use the |
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117 | default loop as this is fastest (perl-wise), best supported by other |
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118 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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119 | |
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120 | For specific programs you can create additional event loops dynamically. |
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121 | |
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122 | If you want to take advantage of kqueue (which often works properly for |
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123 | sockets only) even though the default loop doesn't enable it, you can |
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124 | I<embed> a kqueue loop into the default loop: running the default loop |
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125 | will then also service the kqueue loop to some extent. See the example in |
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126 | the section about embed watchers for an example on how to achieve that. |
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127 | |
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128 | =over 4 |
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129 | |
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130 | =item $loop = new EV::Loop [$flags] |
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131 | |
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132 | Create a new event loop as per the specified flags. Please refer to |
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133 | the C<ev_loop_new ()> function description in the libev documentation |
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134 | (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>, |
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135 | or locally-installed as F<EV::libev> manpage) for more info. |
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136 | |
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137 | The loop will automatically be destroyed when it is no longer referenced |
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138 | by any watcher and the loop object goes out of scope. |
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139 | |
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140 | If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK> |
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141 | is recommended, as only the default event loop is protected by this |
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142 | module. If you I<are> embedding this loop in the default loop, this is not |
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143 | necessary, as C<EV::embed> automatically does the right thing on fork. |
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144 | |
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145 | =item $loop->loop_fork |
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146 | |
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147 | Must be called after a fork in the child, before entering or continuing |
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148 | the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls |
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149 | this function automatically, at some performance loss (refer to the libev |
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150 | documentation). |
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151 | |
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152 | =item $loop->loop_verify |
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153 | |
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154 | Calls C<ev_verify> to make internal consistency checks (for debugging |
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155 | libev) and abort the program if any data structures were found to be |
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156 | corrupted. |
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157 | |
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158 | =item $loop = EV::default_loop [$flags] |
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159 | |
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160 | Return the default loop (which is a singleton object). Since this module |
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161 | already creates the default loop with default flags, specifying flags here |
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162 | will not have any effect unless you destroy the default loop first, which |
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163 | isn't supported. So in short: don't do it, and if you break it, you get to |
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164 | keep the pieces. |
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165 | |
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166 | =back |
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167 | |
78 | |
168 | |
79 | =head1 BASIC INTERFACE |
169 | =head1 BASIC INTERFACE |
80 | |
170 | |
81 | =over 4 |
171 | =over 4 |
82 | |
172 | |
83 | =item $EV::DIED |
173 | =item $EV::DIED |
84 | |
174 | |
85 | Must contain a reference to a function that is called when a callback |
175 | Must contain a reference to a function that is called when a callback |
86 | throws an exception (with $@ containing thr error). The default prints an |
176 | throws an exception (with $@ containing the error). The default prints an |
87 | informative message and continues. |
177 | informative message and continues. |
88 | |
178 | |
89 | If this callback throws an exception it will be silently ignored. |
179 | If this callback throws an exception it will be silently ignored. |
90 | |
180 | |
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181 | =item $flags = EV::supported_backends |
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182 | |
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183 | =item $flags = EV::recommended_backends |
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184 | |
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185 | =item $flags = EV::embeddable_backends |
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186 | |
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187 | Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this |
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188 | instance of EV, the set of recommended backends (supposed to be good) for |
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189 | this platform and the set of embeddable backends (see EMBED WATCHERS). |
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190 | |
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191 | =item EV::sleep $seconds |
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192 | |
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193 | Block the process for the given number of (fractional) seconds. |
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194 | |
91 | =item $time = EV::time |
195 | =item $time = EV::time |
92 | |
196 | |
93 | Returns the current time in (fractional) seconds since the epoch. |
197 | Returns the current time in (fractional) seconds since the epoch. |
94 | |
198 | |
95 | =item $time = EV::now |
199 | =item $time = EV::now |
96 | |
200 | |
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201 | =item $time = $loop->now |
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202 | |
97 | Returns the time the last event loop iteration has been started. This |
203 | Returns the time the last event loop iteration has been started. This |
98 | is the time that (relative) timers are based on, and refering to it is |
204 | is the time that (relative) timers are based on, and referring to it is |
99 | usually faster then calling EV::time. |
205 | usually faster then calling EV::time. |
100 | |
206 | |
101 | =item $method = EV::ev_method |
207 | =item EV::now_update |
102 | |
208 | |
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209 | =item $loop->now_update |
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210 | |
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211 | Establishes the current time by querying the kernel, updating the time |
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212 | returned by C<EV::now> in the progress. This is a costly operation and |
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213 | is usually done automatically within C<EV::loop>. |
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214 | |
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215 | This function is rarely useful, but when some event callback runs for a |
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216 | very long time without entering the event loop, updating libev's idea of |
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217 | the current time is a good idea. |
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218 | |
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219 | =item EV::suspend |
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220 | |
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221 | =item $loop->suspend |
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222 | |
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223 | =item EV::resume |
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224 | |
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225 | =item $loop->resume |
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226 | |
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227 | These two functions suspend and resume a loop, for use when the loop is |
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228 | not used for a while and timeouts should not be processed. |
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229 | |
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230 | A typical use case would be an interactive program such as a game: When |
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231 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
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232 | would be best to handle timeouts as if no time had actually passed while |
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233 | the program was suspended. This can be achieved by calling C<suspend> |
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234 | in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling |
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235 | C<resume> directly afterwards to resume timer processing. |
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236 | |
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237 | Effectively, all C<timer> watchers will be delayed by the time spend |
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238 | between C<suspend> and C<resume>, and all C<periodic> watchers |
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239 | will be rescheduled (that is, they will lose any events that would have |
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240 | occured while suspended). |
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241 | |
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242 | After calling C<suspend> you B<must not> call I<any> function on the given |
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243 | loop other than C<resume>, and you B<must not> call C<resume> |
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244 | without a previous call to C<suspend>. |
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245 | |
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246 | Calling C<suspend>/C<resume> has the side effect of updating the event |
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247 | loop time (see C<now_update>). |
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248 | |
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249 | =item $backend = EV::backend |
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250 | |
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251 | =item $backend = $loop->backend |
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252 | |
103 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
253 | Returns an integer describing the backend used by libev (EV::BACKEND_SELECT |
104 | or EV::METHOD_EPOLL). |
254 | or EV::BACKEND_EPOLL). |
105 | |
255 | |
106 | =item EV::loop [$flags] |
256 | =item EV::loop [$flags] |
107 | |
257 | |
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258 | =item $loop->loop ([$flags]) |
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259 | |
108 | Begin checking for events and calling callbacks. It returns when a |
260 | Begin checking for events and calling callbacks. It returns when a |
109 | callback calls EV::loop_done. |
261 | callback calls EV::unloop. |
110 | |
262 | |
111 | The $flags argument can be one of the following: |
263 | The $flags argument can be one of the following: |
112 | |
264 | |
113 | 0 as above |
265 | 0 as above |
114 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
266 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
115 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
267 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
116 | |
268 | |
117 | =item EV::loop_done [$how] |
269 | =item EV::unloop [$how] |
118 | |
270 | |
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271 | =item $loop->unloop ([$how]) |
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272 | |
119 | When called with no arguments or an argument of 1, makes the innermost |
273 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
120 | call to EV::loop return. |
274 | innermost call to EV::loop return. |
121 | |
275 | |
122 | When called with an agrument of 2, all calls to EV::loop will return as |
276 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
123 | fast as possible. |
277 | fast as possible. |
124 | |
278 | |
125 | =back |
279 | =item $count = EV::loop_count |
126 | |
280 | |
127 | =head2 WATCHER |
281 | =item $count = $loop->loop_count |
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282 | |
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283 | Return the number of times the event loop has polled for new |
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284 | events. Sometimes useful as a generation counter. |
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285 | |
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286 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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287 | |
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288 | =item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
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289 | |
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290 | This function rolls together an I/O and a timer watcher for a single |
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291 | one-shot event without the need for managing a watcher object. |
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292 | |
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293 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
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294 | must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
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295 | | EV::WRITE>, indicating the type of I/O event you want to wait for. If |
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296 | you do not want to wait for some I/O event, specify C<undef> for |
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297 | C<$fh_or_undef> and C<0> for C<$events>). |
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298 | |
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299 | If timeout is C<undef> or negative, then there will be no |
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300 | timeout. Otherwise a EV::timer with this value will be started. |
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301 | |
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302 | When an error occurs or either the timeout or I/O watcher triggers, then |
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303 | the callback will be called with the received event set (in general |
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304 | you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, |
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305 | C<EV::WRITE> and C<EV::TIMEOUT>). |
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306 | |
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307 | EV::once doesn't return anything: the watchers stay active till either |
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308 | of them triggers, then they will be stopped and freed, and the callback |
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309 | invoked. |
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310 | |
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311 | =item EV::feed_fd_event ($fd, $revents) |
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312 | |
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313 | =item $loop->feed_fd_event ($fd, $revents) |
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314 | |
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315 | Feed an event on a file descriptor into EV. EV will react to this call as |
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316 | if the readyness notifications specified by C<$revents> (a combination of |
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317 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
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318 | |
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319 | =item EV::feed_signal_event ($signal) |
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320 | |
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321 | Feed a signal event into EV. EV will react to this call as if the signal |
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322 | specified by C<$signal> had occured. |
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323 | |
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324 | =item EV::set_io_collect_interval $time |
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325 | |
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326 | =item $loop->set_io_collect_interval ($time) |
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327 | |
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328 | =item EV::set_timeout_collect_interval $time |
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329 | |
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330 | =item $loop->set_timeout_collect_interval ($time) |
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331 | |
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332 | These advanced functions set the minimum block interval when polling for I/O events and the minimum |
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333 | wait interval for timer events. See the libev documentation at |
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334 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> |
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335 | (locally installed as F<EV::libev>) for a more detailed discussion. |
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336 | |
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337 | =back |
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338 | |
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339 | |
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340 | =head1 WATCHER OBJECTS |
128 | |
341 | |
129 | A watcher is an object that gets created to record your interest in some |
342 | A watcher is an object that gets created to record your interest in some |
130 | event. For instance, if you want to wait for STDIN to become readable, you |
343 | event. For instance, if you want to wait for STDIN to become readable, you |
131 | would create an EV::io watcher for that: |
344 | would create an EV::io watcher for that: |
132 | |
345 | |
133 | my $watcher = EV::io *STDIN, EV::READ, sub { |
346 | my $watcher = EV::io *STDIN, EV::READ, sub { |
134 | my ($watcher, $revents) = @_; |
347 | my ($watcher, $revents) = @_; |
135 | warn "yeah, STDIN should not be readable without blocking!\n" |
348 | warn "yeah, STDIN should now be readable without blocking!\n" |
136 | }; |
349 | }; |
137 | |
350 | |
138 | All watchers can be active (waiting for events) or inactive (paused). Only |
351 | All watchers can be active (waiting for events) or inactive (paused). Only |
139 | active watchers will have their callbacks invoked. All callbacks will be |
352 | active watchers will have their callbacks invoked. All callbacks will be |
140 | called with at least two arguments: the watcher and a bitmask of received |
353 | called with at least two arguments: the watcher and a bitmask of received |
141 | events. |
354 | events. |
142 | |
355 | |
143 | Each watcher type has its associated bit in revents, so you can use the |
356 | Each watcher type has its associated bit in revents, so you can use the |
144 | same callback for multiple watchers. The event mask is named after the |
357 | same callback for multiple watchers. The event mask is named after the |
145 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
358 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
146 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
359 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
147 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
360 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
148 | uses EV::TIMEOUT). |
361 | uses EV::TIMEOUT). |
149 | |
362 | |
150 | In the rare case where one wants to create a watcher but not start it at |
363 | In the rare case where one wants to create a watcher but not start it at |
151 | the same time, each constructor has a variant with a trailing C<_ns> in |
364 | the same time, each constructor has a variant with a trailing C<_ns> in |
152 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
365 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
153 | |
366 | |
154 | Please note that a watcher will automatically be stopped when the watcher |
367 | Please note that a watcher will automatically be stopped when the watcher |
155 | object is returned, so you I<need> to keep the watcher objects returned by |
368 | object is destroyed, so you I<need> to keep the watcher objects returned by |
156 | the constructors. |
369 | the constructors. |
157 | |
370 | |
158 | =head2 WATCHER TYPES |
371 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
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372 | ->fh and so on) automatically stop and start it again if it is active, |
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373 | which means pending events get lost. |
159 | |
374 | |
160 | Now lets move to the existing watcher types and asociated methods. |
375 | =head2 COMMON WATCHER METHODS |
161 | |
376 | |
162 | The following methods are available for all watchers. Then followes a |
377 | This section lists methods common to all watchers. |
163 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
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164 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
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165 | any type-specific methods (if any). |
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166 | |
378 | |
167 | =over 4 |
379 | =over 4 |
168 | |
380 | |
169 | =item $w->start |
381 | =item $w->start |
170 | |
382 | |
… | |
… | |
174 | |
386 | |
175 | =item $w->stop |
387 | =item $w->stop |
176 | |
388 | |
177 | Stop a watcher if it is active. Also clear any pending events (events that |
389 | Stop a watcher if it is active. Also clear any pending events (events that |
178 | have been received but that didn't yet result in a callback invocation), |
390 | have been received but that didn't yet result in a callback invocation), |
179 | regardless of wether the watcher was active or not. |
391 | regardless of whether the watcher was active or not. |
180 | |
392 | |
181 | =item $bool = $w->is_active |
393 | =item $bool = $w->is_active |
182 | |
394 | |
183 | Returns true if the watcher is active, false otherwise. |
395 | Returns true if the watcher is active, false otherwise. |
184 | |
396 | |
|
|
397 | =item $current_data = $w->data |
|
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398 | |
|
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399 | =item $old_data = $w->data ($new_data) |
|
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400 | |
|
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401 | Queries a freely usable data scalar on the watcher and optionally changes |
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402 | it. This is a way to associate custom data with a watcher: |
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403 | |
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404 | my $w = EV::timer 60, 0, sub { |
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405 | warn $_[0]->data; |
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406 | }; |
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407 | $w->data ("print me!"); |
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408 | |
185 | =item $current_cb = $w->cb |
409 | =item $current_cb = $w->cb |
186 | |
410 | |
187 | =item $old_cb = $w->cb ($new_cb) |
411 | =item $old_cb = $w->cb ($new_cb) |
188 | |
412 | |
189 | Queries the callback on the watcher and optionally changes it. You cna do |
413 | Queries the callback on the watcher and optionally changes it. You can do |
190 | this at any time. |
414 | this at any time without the watcher restarting. |
191 | |
415 | |
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416 | =item $current_priority = $w->priority |
|
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417 | |
|
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418 | =item $old_priority = $w->priority ($new_priority) |
|
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419 | |
|
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420 | Queries the priority on the watcher and optionally changes it. Pending |
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421 | watchers with higher priority will be invoked first. The valid range of |
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422 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
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423 | -2). If the priority is outside this range it will automatically be |
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424 | normalised to the nearest valid priority. |
|
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425 | |
|
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426 | The default priority of any newly-created watcher is 0. |
|
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427 | |
|
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428 | Note that the priority semantics have not yet been fleshed out and are |
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429 | subject to almost certain change. |
|
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430 | |
192 | =item $w->trigger ($revents) |
431 | =item $w->invoke ($revents) |
193 | |
432 | |
194 | Call the callback *now* with the given event mask. |
433 | Call the callback *now* with the given event mask. |
195 | |
434 | |
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435 | =item $w->feed_event ($revents) |
|
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436 | |
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437 | Feed some events on this watcher into EV. EV will react to this call as if |
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438 | the watcher had received the given C<$revents> mask. |
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439 | |
|
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440 | =item $revents = $w->clear_pending |
|
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441 | |
|
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442 | If the watcher is pending, this function clears its pending status and |
|
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443 | returns its C<$revents> bitset (as if its callback was invoked). If the |
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444 | watcher isn't pending it does nothing and returns C<0>. |
|
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445 | |
|
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446 | =item $previous_state = $w->keepalive ($bool) |
|
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447 | |
|
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448 | Normally, C<EV::loop> will return when there are no active watchers |
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449 | (which is a "deadlock" because no progress can be made anymore). This is |
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450 | convinient because it allows you to start your watchers (and your jobs), |
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451 | call C<EV::loop> once and when it returns you know that all your jobs are |
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452 | finished (or they forgot to register some watchers for their task :). |
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453 | |
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454 | Sometimes, however, this gets in your way, for example when the module |
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455 | that calls C<EV::loop> (usually the main program) is not the same module |
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456 | as a long-living watcher (for example a DNS client module written by |
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457 | somebody else even). Then you might want any outstanding requests to be |
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458 | handled, but you would not want to keep C<EV::loop> from returning just |
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459 | because you happen to have this long-running UDP port watcher. |
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460 | |
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461 | In this case you can clear the keepalive status, which means that even |
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462 | though your watcher is active, it won't keep C<EV::loop> from returning. |
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463 | |
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464 | The initial value for keepalive is true (enabled), and you can change it |
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465 | any time. |
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466 | |
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467 | Example: Register an I/O watcher for some UDP socket but do not keep the |
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468 | event loop from running just because of that watcher. |
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469 | |
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470 | my $udp_socket = ... |
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471 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
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472 | $udp_watcher->keepalive (0); |
|
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473 | |
|
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474 | =item $loop = $w->loop |
|
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475 | |
|
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476 | Return the loop that this watcher is attached to. |
|
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477 | |
|
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478 | =back |
|
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479 | |
|
|
480 | |
|
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481 | =head1 WATCHER TYPES |
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482 | |
|
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483 | Each of the following subsections describes a single watcher type. |
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484 | |
|
|
485 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
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486 | |
|
|
487 | =over 4 |
196 | |
488 | |
197 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
489 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
198 | |
490 | |
199 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
491 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
200 | |
492 | |
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493 | =item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
494 | |
|
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495 | =item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
|
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496 | |
201 | As long as the returned watcher object is alive, call the C<$callback> |
497 | As long as the returned watcher object is alive, call the C<$callback> |
202 | when the events specified in C<$eventmask>. |
498 | when at least one of events specified in C<$eventmask> occurs. |
203 | |
499 | |
204 | The $eventmask can be one or more of these constants ORed together: |
500 | The $eventmask can be one or more of these constants ORed together: |
205 | |
501 | |
206 | EV::READ wait until read() wouldn't block anymore |
502 | EV::READ wait until read() wouldn't block anymore |
207 | EV::WRITE wait until write() wouldn't block anymore |
503 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
223 | |
519 | |
224 | =item $old_eventmask = $w->events ($new_eventmask) |
520 | =item $old_eventmask = $w->events ($new_eventmask) |
225 | |
521 | |
226 | Returns the previously set event mask and optionally set a new one. |
522 | Returns the previously set event mask and optionally set a new one. |
227 | |
523 | |
|
|
524 | =back |
|
|
525 | |
|
|
526 | |
|
|
527 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
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528 | |
|
|
529 | =over 4 |
228 | |
530 | |
229 | =item $w = EV::timer $after, $repeat, $callback |
531 | =item $w = EV::timer $after, $repeat, $callback |
230 | |
532 | |
231 | =item $w = EV::timer_ns $after, $repeat, $callback |
533 | =item $w = EV::timer_ns $after, $repeat, $callback |
232 | |
534 | |
233 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
535 | =item $w = $loop->timer ($after, $repeat, $callback) |
234 | the timer will be restarted (with the $repeat value as $after) after the |
536 | |
235 | callback returns. |
537 | =item $w = $loop->timer_ns ($after, $repeat, $callback) |
|
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538 | |
|
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539 | Calls the callback after C<$after> seconds (which may be fractional). If |
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540 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
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541 | value as $after) after the callback returns. |
236 | |
542 | |
237 | This means that the callback would be called roughly after C<$after> |
543 | This means that the callback would be called roughly after C<$after> |
238 | seconds, and then every C<$repeat> seconds. "Roughly" because the time of |
544 | seconds, and then every C<$repeat> seconds. The timer does his best not |
239 | callback processing is not taken into account, so the timer will slowly |
545 | to drift, but it will not invoke the timer more often then once per event |
240 | drift. If that isn't acceptable, look at EV::periodic. |
546 | loop iteration, and might drift in other cases. If that isn't acceptable, |
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|
547 | look at EV::periodic, which can provide long-term stable timers. |
241 | |
548 | |
242 | The timer is based on a monotonic clock, that is if somebody is sitting |
549 | The timer is based on a monotonic clock, that is, if somebody is sitting |
243 | in front of the machine while the timer is running and changes the system |
550 | in front of the machine while the timer is running and changes the system |
244 | clock, the timer will nevertheless run (roughly) the same time. |
551 | clock, the timer will nevertheless run (roughly) the same time. |
245 | |
552 | |
246 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
553 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
247 | |
554 | |
248 | =item $w->set ($after, $repeat) |
555 | =item $w->set ($after, $repeat) |
249 | |
556 | |
250 | Reconfigures the watcher, see the constructor above for details. Can be at |
557 | Reconfigures the watcher, see the constructor above for details. Can be called at |
251 | any time. |
558 | any time. |
252 | |
559 | |
253 | =item $w->again |
560 | =item $w->again |
254 | |
561 | |
255 | Similar to the C<start> method, but has special semantics for repeating timers: |
562 | Similar to the C<start> method, but has special semantics for repeating timers: |
|
|
563 | |
|
|
564 | If the timer is active and non-repeating, it will be stopped. |
256 | |
565 | |
257 | If the timer is active and repeating, reset the timeout to occur |
566 | If the timer is active and repeating, reset the timeout to occur |
258 | C<$repeat> seconds after now. |
567 | C<$repeat> seconds after now. |
259 | |
568 | |
260 | If the timer is active and non-repeating, it will be stopped. |
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261 | |
|
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262 | If the timer is in active and repeating, start it. |
569 | If the timer is inactive and repeating, start it using the repeat value. |
263 | |
570 | |
264 | Otherwise do nothing. |
571 | Otherwise do nothing. |
265 | |
572 | |
266 | This behaviour is useful when you have a timeout for some IO |
573 | This behaviour is useful when you have a timeout for some IO |
267 | operation. You create a timer object with the same value for C<$after> and |
574 | operation. You create a timer object with the same value for C<$after> and |
268 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
575 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
269 | on the timeout. |
576 | on the timeout. |
270 | |
577 | |
|
|
578 | =back |
271 | |
579 | |
|
|
580 | |
|
|
581 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
582 | |
|
|
583 | =over 4 |
|
|
584 | |
272 | =item $w = EV::periodic $at, $interval, $callback |
585 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
273 | |
586 | |
274 | =item $w = EV::periodic_ns $at, $interval, $callback |
587 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
275 | |
588 | |
276 | Similar to EV::timer, but the time is given as an absolute point in time |
589 | =item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
277 | (C<$at>), plus an optional C<$interval>. |
|
|
278 | |
590 | |
279 | If the C<$interval> is zero, then the callback will be called at the time |
591 | =item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
280 | C<$at> if that is in the future, or as soon as possible if it is in the |
|
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281 | past. It will not automatically repeat. |
|
|
282 | |
592 | |
283 | If the C<$interval> is nonzero, then the watcher will always be scheduled |
593 | Similar to EV::timer, but is not based on relative timeouts but on |
284 | to time out at the next C<$at + N * $interval> time. |
594 | absolute times. Apart from creating "simple" timers that trigger "at" the |
|
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595 | specified time, it can also be used for non-drifting absolute timers and |
|
|
596 | more complex, cron-like, setups that are not adversely affected by time |
|
|
597 | jumps (i.e. when the system clock is changed by explicit date -s or other |
|
|
598 | means such as ntpd). It is also the most complex watcher type in EV. |
285 | |
599 | |
286 | This can be used to schedule a callback to run at very regular intervals, |
600 | It has three distinct "modes": |
287 | as long as the processing time is less then the interval (otherwise |
601 | |
288 | obviously events will be skipped). |
602 | =over 4 |
|
|
603 | |
|
|
604 | =item * absolute timer ($interval = $reschedule_cb = 0) |
|
|
605 | |
|
|
606 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
|
|
607 | will not adjust when a time jump occurs, that is, if it is to be run |
|
|
608 | at January 1st 2011 then it will run when the system time reaches or |
|
|
609 | surpasses this time. |
|
|
610 | |
|
|
611 | =item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
612 | |
|
|
613 | In this mode the watcher will always be scheduled to time out at the |
|
|
614 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
|
|
615 | regardless of any time jumps. |
|
|
616 | |
|
|
617 | This can be used to create timers that do not drift with respect to system |
|
|
618 | time: |
|
|
619 | |
|
|
620 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
|
621 | |
|
|
622 | That doesn't mean there will always be 3600 seconds in between triggers, |
|
|
623 | but only that the the clalback will be called when the system time shows a |
|
|
624 | full hour (UTC). |
289 | |
625 | |
290 | Another way to think about it (for the mathematically inclined) is that |
626 | Another way to think about it (for the mathematically inclined) is that |
291 | EV::periodic will try to run the callback at the next possible time where |
627 | EV::periodic will try to run the callback in this mode at the next |
292 | C<$time = $at (mod $interval)>, regardless of any time jumps. |
628 | possible time where C<$time = $at (mod $interval)>, regardless of any time |
|
|
629 | jumps. |
293 | |
630 | |
294 | This periodic timer is based on "wallclock time", that is, if the clock |
631 | =item * manual reschedule mode ($reschedule_cb = coderef) |
295 | changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at |
632 | |
296 | the specified time. This means it will never drift (it might jitter, but |
633 | In this mode $interval and $at are both being ignored. Instead, each |
297 | it will not drift). |
634 | time the periodic watcher gets scheduled, the reschedule callback |
|
|
635 | ($reschedule_cb) will be called with the watcher as first, and the current |
|
|
636 | time as second argument. |
|
|
637 | |
|
|
638 | I<This callback MUST NOT stop or destroy this or any other periodic |
|
|
639 | watcher, ever, and MUST NOT call any event loop functions or methods>. If |
|
|
640 | you need to stop it, return 1e30 and stop it afterwards. You may create |
|
|
641 | and start a C<EV::prepare> watcher for this task. |
|
|
642 | |
|
|
643 | It must return the next time to trigger, based on the passed time value |
|
|
644 | (that is, the lowest time value larger than or equal to to the second |
|
|
645 | argument). It will usually be called just before the callback will be |
|
|
646 | triggered, but might be called at other times, too. |
|
|
647 | |
|
|
648 | This can be used to create very complex timers, such as a timer that |
|
|
649 | triggers on each midnight, local time (actually 24 hours after the last |
|
|
650 | midnight, to keep the example simple. If you know a way to do it correctly |
|
|
651 | in about the same space (without requiring elaborate modules), drop me a |
|
|
652 | note :): |
|
|
653 | |
|
|
654 | my $daily = EV::periodic 0, 0, sub { |
|
|
655 | my ($w, $now) = @_; |
|
|
656 | |
|
|
657 | use Time::Local (); |
|
|
658 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
|
659 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
|
660 | }, sub { |
|
|
661 | print "it's midnight or likely shortly after, now\n"; |
|
|
662 | }; |
|
|
663 | |
|
|
664 | =back |
298 | |
665 | |
299 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
666 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
300 | |
667 | |
301 | =item $w->set ($at, $interval) |
668 | =item $w->set ($at, $interval, $reschedule_cb) |
302 | |
669 | |
303 | Reconfigures the watcher, see the constructor above for details. Can be at |
670 | Reconfigures the watcher, see the constructor above for details. Can be called at |
304 | any time. |
671 | any time. |
305 | |
672 | |
|
|
673 | =item $w->again |
|
|
674 | |
|
|
675 | Simply stops and starts the watcher again. |
|
|
676 | |
|
|
677 | =item $time = $w->at |
|
|
678 | |
|
|
679 | Return the time that the watcher is expected to trigger next. |
|
|
680 | |
|
|
681 | =back |
|
|
682 | |
|
|
683 | |
|
|
684 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
685 | |
|
|
686 | =over 4 |
306 | |
687 | |
307 | =item $w = EV::signal $signal, $callback |
688 | =item $w = EV::signal $signal, $callback |
308 | |
689 | |
309 | =item $w = EV::signal_ns $signal, $callback |
690 | =item $w = EV::signal_ns $signal, $callback |
310 | |
691 | |
311 | Call the callback when $signal is received (the signal can be specified |
692 | Call the callback when $signal is received (the signal can be specified by |
312 | by number or by name, just as with kill or %SIG). |
693 | number or by name, just as with C<kill> or C<%SIG>). |
313 | |
694 | |
314 | EV will grab the signal for the process (the kernel only allows one |
695 | EV will grab the signal for the process (the kernel only allows one |
315 | component to receive a signal at a time) when you start a signal watcher, |
696 | component to receive a signal at a time) when you start a signal watcher, |
316 | and removes it again when you stop it. Perl does the same when you |
697 | and removes it again when you stop it. Perl does the same when you |
317 | add/remove callbacks to %SIG, so watch out. |
698 | add/remove callbacks to C<%SIG>, so watch out. |
318 | |
699 | |
319 | You can have as many signal watchers per signal as you want. |
700 | You can have as many signal watchers per signal as you want. |
320 | |
701 | |
321 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
702 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
322 | |
703 | |
323 | =item $w->set ($signal) |
704 | =item $w->set ($signal) |
324 | |
705 | |
325 | Reconfigures the watcher, see the constructor above for details. Can be at |
706 | Reconfigures the watcher, see the constructor above for details. Can be |
326 | any time. |
707 | called at any time. |
327 | |
708 | |
328 | =item $current_signum = $w->signal |
709 | =item $current_signum = $w->signal |
329 | |
710 | |
330 | =item $old_signum = $w->signal ($new_signal) |
711 | =item $old_signum = $w->signal ($new_signal) |
331 | |
712 | |
332 | Returns the previously set signal (always as a number not name) and |
713 | Returns the previously set signal (always as a number not name) and |
333 | optionally set a new one. |
714 | optionally set a new one. |
334 | |
715 | |
|
|
716 | =back |
335 | |
717 | |
|
|
718 | |
|
|
719 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
720 | |
|
|
721 | =over 4 |
|
|
722 | |
336 | =item $w = EV::child $pid, $callback |
723 | =item $w = EV::child $pid, $trace, $callback |
337 | |
724 | |
338 | =item $w = EV::child_ns $pid, $callback |
725 | =item $w = EV::child_ns $pid, $trace, $callback |
|
|
726 | |
|
|
727 | =item $w = $loop->child ($pid, $trace, $callback) |
|
|
728 | |
|
|
729 | =item $w = $loop->child_ns ($pid, $trace, $callback) |
339 | |
730 | |
340 | Call the callback when a status change for pid C<$pid> (or any pid |
731 | Call the callback when a status change for pid C<$pid> (or any pid |
341 | if C<$pid> is 0) has been received. More precisely: when the process |
732 | if C<$pid> is 0) has been received (a status change happens when the |
|
|
733 | process terminates or is killed, or, when trace is true, additionally when |
|
|
734 | it is stopped or continued). More precisely: when the process receives |
342 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
735 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
343 | changed/zombie children and call the callback. |
736 | changed/zombie children and call the callback. |
344 | |
737 | |
345 | Unlike all other callbacks, this callback will be called with an |
738 | It is valid (and fully supported) to install a child watcher after a child |
346 | additional third argument which is the exit status. See the C<waitpid> |
739 | has exited but before the event loop has started its next iteration (for |
347 | function for details. |
740 | example, first you C<fork>, then the new child process might exit, and |
|
|
741 | only then do you install a child watcher in the parent for the new pid). |
348 | |
742 | |
|
|
743 | You can access both exit (or tracing) status and pid by using the |
|
|
744 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
745 | |
349 | You can have as many pid watchers per pid as you want. |
746 | You can have as many pid watchers per pid as you want, they will all be |
|
|
747 | called. |
350 | |
748 | |
351 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
749 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
352 | |
750 | |
353 | =item $w->set ($pid) |
751 | =item $w->set ($pid, $trace) |
354 | |
752 | |
355 | Reconfigures the watcher, see the constructor above for details. Can be at |
753 | Reconfigures the watcher, see the constructor above for details. Can be called at |
356 | any time. |
754 | any time. |
357 | |
755 | |
358 | =item $current_pid = $w->pid |
756 | =item $current_pid = $w->pid |
359 | |
757 | |
360 | =item $old_pid = $w->pid ($new_pid) |
|
|
361 | |
|
|
362 | Returns the previously set process id and optionally set a new one. |
758 | Returns the previously set process id and optionally set a new one. |
363 | |
759 | |
|
|
760 | =item $exit_status = $w->rstatus |
|
|
761 | |
|
|
762 | Return the exit/wait status (as returned by waitpid, see the waitpid entry |
|
|
763 | in perlfunc). |
|
|
764 | |
|
|
765 | =item $pid = $w->rpid |
|
|
766 | |
|
|
767 | Return the pid of the awaited child (useful when you have installed a |
|
|
768 | watcher for all pids). |
|
|
769 | |
|
|
770 | =back |
|
|
771 | |
|
|
772 | |
|
|
773 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
774 | |
|
|
775 | =over 4 |
|
|
776 | |
|
|
777 | =item $w = EV::stat $path, $interval, $callback |
|
|
778 | |
|
|
779 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
780 | |
|
|
781 | =item $w = $loop->stat ($path, $interval, $callback) |
|
|
782 | |
|
|
783 | =item $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
784 | |
|
|
785 | Call the callback when a file status change has been detected on |
|
|
786 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
787 | to "path does not exist" is a status change like any other. |
|
|
788 | |
|
|
789 | The C<$interval> is a recommended polling interval for systems where |
|
|
790 | OS-supported change notifications don't exist or are not supported. If |
|
|
791 | you use C<0> then an unspecified default is used (which is highly |
|
|
792 | recommended!), which is to be expected to be around five seconds usually. |
|
|
793 | |
|
|
794 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
795 | as even with OS-supported change notifications, this can be |
|
|
796 | resource-intensive. |
|
|
797 | |
|
|
798 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
799 | |
|
|
800 | =item ... = $w->stat |
|
|
801 | |
|
|
802 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
803 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
804 | well as EV's idea of the current stat values) to the values found. |
|
|
805 | |
|
|
806 | In scalar context, a boolean is return indicating success or failure of |
|
|
807 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
808 | (except that the blksize and blocks fields are not reliable). |
|
|
809 | |
|
|
810 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
811 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
812 | was successful then nlink is guaranteed to be non-zero). |
|
|
813 | |
|
|
814 | See also the next two entries for more info. |
|
|
815 | |
|
|
816 | =item ... = $w->attr |
|
|
817 | |
|
|
818 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
819 | the values most recently detected by EV. See the next entry for more info. |
|
|
820 | |
|
|
821 | =item ... = $w->prev |
|
|
822 | |
|
|
823 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
824 | the previous set of values, before the change. |
|
|
825 | |
|
|
826 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
827 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
828 | returns the values found leading to the change detection. The difference (if any) |
|
|
829 | between C<prev> and C<attr> is what triggered the callback. |
|
|
830 | |
|
|
831 | If you did something to the filesystem object and do not want to trigger |
|
|
832 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
833 | current attributes are. |
|
|
834 | |
|
|
835 | =item $w->set ($path, $interval) |
|
|
836 | |
|
|
837 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
838 | called at any time. |
|
|
839 | |
|
|
840 | =item $current_path = $w->path |
|
|
841 | |
|
|
842 | =item $old_path = $w->path ($new_path) |
|
|
843 | |
|
|
844 | Returns the previously set path and optionally set a new one. |
|
|
845 | |
|
|
846 | =item $current_interval = $w->interval |
|
|
847 | |
|
|
848 | =item $old_interval = $w->interval ($new_interval) |
|
|
849 | |
|
|
850 | Returns the previously set interval and optionally set a new one. Can be |
|
|
851 | used to query the actual interval used. |
|
|
852 | |
|
|
853 | =back |
|
|
854 | |
|
|
855 | |
|
|
856 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
857 | |
|
|
858 | =over 4 |
364 | |
859 | |
365 | =item $w = EV::idle $callback |
860 | =item $w = EV::idle $callback |
366 | |
861 | |
367 | =item $w = EV::idle_ns $callback |
862 | =item $w = EV::idle_ns $callback |
368 | |
863 | |
369 | Call the callback when there are no pending io, timer/periodic, signal or |
864 | =item $w = $loop->idle ($callback) |
370 | child events, i.e. when the process is idle. |
865 | |
|
|
866 | =item $w = $loop->idle_ns ($callback) |
|
|
867 | |
|
|
868 | Call the callback when there are no other pending watchers of the same or |
|
|
869 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
870 | same or lower priority, of course). They are called idle watchers because |
|
|
871 | when the watcher is the highest priority pending event in the process, the |
|
|
872 | process is considered to be idle at that priority. |
|
|
873 | |
|
|
874 | If you want a watcher that is only ever called when I<no> other events are |
|
|
875 | outstanding you have to set the priority to C<EV::MINPRI>. |
371 | |
876 | |
372 | The process will not block as long as any idle watchers are active, and |
877 | The process will not block as long as any idle watchers are active, and |
373 | they will be called repeatedly until stopped. |
878 | they will be called repeatedly until stopped. |
374 | |
879 | |
|
|
880 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
881 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
882 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
883 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
884 | pending with the C<0>-priority idle watcher be invoked. |
|
|
885 | |
375 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
886 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
376 | |
887 | |
|
|
888 | =back |
|
|
889 | |
|
|
890 | |
|
|
891 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
892 | |
|
|
893 | =over 4 |
377 | |
894 | |
378 | =item $w = EV::prepare $callback |
895 | =item $w = EV::prepare $callback |
379 | |
896 | |
380 | =item $w = EV::prepare_ns $callback |
897 | =item $w = EV::prepare_ns $callback |
|
|
898 | |
|
|
899 | =item $w = $loop->prepare ($callback) |
|
|
900 | |
|
|
901 | =item $w = $loop->prepare_ns ($callback) |
381 | |
902 | |
382 | Call the callback just before the process would block. You can still |
903 | Call the callback just before the process would block. You can still |
383 | create/modify any watchers at this point. |
904 | create/modify any watchers at this point. |
384 | |
905 | |
385 | See the EV::check watcher, below, for explanations and an example. |
906 | See the EV::check watcher, below, for explanations and an example. |
386 | |
907 | |
387 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
908 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
388 | |
909 | |
|
|
910 | =back |
|
|
911 | |
|
|
912 | |
|
|
913 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
914 | |
|
|
915 | =over 4 |
389 | |
916 | |
390 | =item $w = EV::check $callback |
917 | =item $w = EV::check $callback |
391 | |
918 | |
392 | =item $w = EV::check_ns $callback |
919 | =item $w = EV::check_ns $callback |
|
|
920 | |
|
|
921 | =item $w = $loop->check ($callback) |
|
|
922 | |
|
|
923 | =item $w = $loop->check_ns ($callback) |
393 | |
924 | |
394 | Call the callback just after the process wakes up again (after it has |
925 | Call the callback just after the process wakes up again (after it has |
395 | gathered events), but before any other callbacks have been invoked. |
926 | gathered events), but before any other callbacks have been invoked. |
396 | |
927 | |
397 | This is used to integrate other event-based software into the EV |
928 | This is used to integrate other event-based software into the EV |
… | |
… | |
405 | # do nothing unless active |
936 | # do nothing unless active |
406 | $dispatcher->{_event_queue_h} |
937 | $dispatcher->{_event_queue_h} |
407 | or return; |
938 | or return; |
408 | |
939 | |
409 | # make the dispatcher handle any outstanding stuff |
940 | # make the dispatcher handle any outstanding stuff |
|
|
941 | ... not shown |
410 | |
942 | |
411 | # create an IO watcher for each and every socket |
943 | # create an I/O watcher for each and every socket |
412 | @snmp_watcher = ( |
944 | @snmp_watcher = ( |
413 | (map { EV::io $_, EV::READ, sub { } } |
945 | (map { EV::io $_, EV::READ, sub { } } |
414 | keys %{ $dispatcher->{_descriptors} }), |
946 | keys %{ $dispatcher->{_descriptors} }), |
|
|
947 | |
|
|
948 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
949 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
950 | 0, sub { }, |
415 | ); |
951 | ); |
416 | |
|
|
417 | # if there are any timeouts, also create a timer |
|
|
418 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
419 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
420 | }; |
952 | }; |
421 | |
953 | |
422 | The callbacks are irrelevant, the only purpose of those watchers is |
954 | The callbacks are irrelevant (and are not even being called), the |
423 | to wake up the process as soon as one of those events occurs (socket |
955 | only purpose of those watchers is to wake up the process as soon as |
424 | readable, or timer timed out). The corresponding EV::check watcher will then |
956 | one of those events occurs (socket readable, or timer timed out). The |
425 | clean up: |
957 | corresponding EV::check watcher will then clean up: |
426 | |
958 | |
427 | our $snmp_check = EV::check sub { |
959 | our $snmp_check = EV::check sub { |
428 | # destroy all watchers |
960 | # destroy all watchers |
429 | @snmp_watcher = (); |
961 | @snmp_watcher = (); |
430 | |
962 | |
431 | # make the dispatcher handle any new stuff |
963 | # make the dispatcher handle any new stuff |
|
|
964 | ... not shown |
432 | }; |
965 | }; |
433 | |
966 | |
434 | The callbacks of the created watchers will not be called as the watchers |
967 | The callbacks of the created watchers will not be called as the watchers |
435 | are destroyed before this cna happen (remember EV::check gets called |
968 | are destroyed before this can happen (remember EV::check gets called |
436 | first). |
969 | first). |
437 | |
970 | |
438 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
971 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
439 | |
972 | |
440 | =back |
973 | =back |
441 | |
974 | |
|
|
975 | |
|
|
976 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
977 | |
|
|
978 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
979 | is done before the event loop blocks next and before C<check> watchers |
|
|
980 | are being called, and only in the child after the fork. |
|
|
981 | |
|
|
982 | =over 4 |
|
|
983 | |
|
|
984 | =item $w = EV::fork $callback |
|
|
985 | |
|
|
986 | =item $w = EV::fork_ns $callback |
|
|
987 | |
|
|
988 | =item $w = $loop->fork ($callback) |
|
|
989 | |
|
|
990 | =item $w = $loop->fork_ns ($callback) |
|
|
991 | |
|
|
992 | Call the callback before the event loop is resumed in the child process |
|
|
993 | after a fork. |
|
|
994 | |
|
|
995 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
996 | |
|
|
997 | =back |
|
|
998 | |
|
|
999 | |
|
|
1000 | =head3 EMBED WATCHERS - when one backend isn't enough... |
|
|
1001 | |
|
|
1002 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1003 | into another (currently only IO events are supported in the embedded |
|
|
1004 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1005 | fashion and must not be used). |
|
|
1006 | |
|
|
1007 | See the libev documentation at |
|
|
1008 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> |
|
|
1009 | (locally installed as F<EV::libev>) for more details. |
|
|
1010 | |
|
|
1011 | In short, this watcher is most useful on BSD systems without working |
|
|
1012 | kqueue to still be able to handle a large number of sockets: |
|
|
1013 | |
|
|
1014 | my $socket_loop; |
|
|
1015 | |
|
|
1016 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
1017 | if ( |
|
|
1018 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
1019 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
1020 | ) { |
|
|
1021 | # use kqueue for sockets |
|
|
1022 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
1023 | } |
|
|
1024 | |
|
|
1025 | # use the default loop otherwise |
|
|
1026 | $socket_loop ||= EV::default_loop; |
|
|
1027 | |
|
|
1028 | =over 4 |
|
|
1029 | |
|
|
1030 | =item $w = EV::embed $otherloop[, $callback] |
|
|
1031 | |
|
|
1032 | =item $w = EV::embed_ns $otherloop[, $callback] |
|
|
1033 | |
|
|
1034 | =item $w = $loop->embed ($otherloop[, $callback]) |
|
|
1035 | |
|
|
1036 | =item $w = $loop->embed_ns ($otherloop[, $callback]) |
|
|
1037 | |
|
|
1038 | Call the callback when the embedded event loop (C<$otherloop>) has any |
|
|
1039 | I/O activity. The C<$callback> is optional: if it is missing, then the |
|
|
1040 | embedded event loop will be managed automatically (which is recommended), |
|
|
1041 | otherwise you have to invoke C<sweep> yourself. |
|
|
1042 | |
|
|
1043 | The C<embed_ns> variant doesn't start (activate) the newly created watcher. |
|
|
1044 | |
|
|
1045 | =back |
|
|
1046 | |
|
|
1047 | =head3 ASYNC WATCHERS - how to wake up another event loop |
|
|
1048 | |
|
|
1049 | Async watchers are provided by EV, but have little use in perl directly, as perl |
|
|
1050 | neither supports threads nor direct access to signal handlers or other |
|
|
1051 | contexts where they could be of value. |
|
|
1052 | |
|
|
1053 | It is, however, possible to use them from the XS level. |
|
|
1054 | |
|
|
1055 | Please see the libev documentation for further details. |
|
|
1056 | |
|
|
1057 | =over 4 |
|
|
1058 | |
|
|
1059 | =item $w = EV::async $callback |
|
|
1060 | |
|
|
1061 | =item $w = EV::async_ns $callback |
|
|
1062 | |
|
|
1063 | =item $w->send |
|
|
1064 | |
|
|
1065 | =item $bool = $w->async_pending |
|
|
1066 | |
|
|
1067 | =back |
|
|
1068 | |
|
|
1069 | |
|
|
1070 | =head1 PERL SIGNALS |
|
|
1071 | |
|
|
1072 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
1073 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
1074 | handled when Perl runs, which means your signal handler might be invoked |
|
|
1075 | only the next time an event callback is invoked. |
|
|
1076 | |
|
|
1077 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
1078 | ensure proper operations with regards to other event watchers. |
|
|
1079 | |
|
|
1080 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
1081 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
1082 | watcher: |
|
|
1083 | |
|
|
1084 | my $async_check = EV::check sub { }; |
|
|
1085 | |
|
|
1086 | This ensures that perl gets into control for a short time to handle any |
|
|
1087 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
1088 | |
442 | =head1 THREADS |
1089 | =head1 THREADS |
443 | |
1090 | |
444 | Threads are not supported by this in any way. Perl pseudo-threads is evil |
1091 | Threads are not supported by this module in any way. Perl pseudo-threads |
445 | stuff and must die. |
1092 | is evil stuff and must die. As soon as Perl gains real threads I will work |
|
|
1093 | on thread support for it. |
|
|
1094 | |
|
|
1095 | =head1 FORK |
|
|
1096 | |
|
|
1097 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
1098 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
1099 | not supported and usually destructive). Libev makes it possible to work |
|
|
1100 | around this by having a function that recreates the kernel state after |
|
|
1101 | fork in the child. |
|
|
1102 | |
|
|
1103 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
1104 | functionality to do this automatically for you. This function is quite |
|
|
1105 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
1106 | negligible, because everything the function currently does is set a flag |
|
|
1107 | that is checked only when the event loop gets used the next time, so when |
|
|
1108 | you do fork but not use EV, the overhead is minimal. |
|
|
1109 | |
|
|
1110 | On win32, there is no notion of fork so all this doesn't apply, of course. |
446 | |
1111 | |
447 | =cut |
1112 | =cut |
448 | |
1113 | |
449 | our $DIED = sub { |
1114 | our $DIED = sub { |
450 | warn "EV: error in callback (ignoring): $@"; |
1115 | warn "EV: error in callback (ignoring): $@"; |
451 | }; |
1116 | }; |
452 | |
1117 | |
453 | init; |
1118 | default_loop |
454 | |
1119 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
455 | push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"]; |
|
|
456 | |
1120 | |
457 | 1; |
1121 | 1; |
458 | |
1122 | |
459 | =head1 SEE ALSO |
1123 | =head1 SEE ALSO |
460 | |
1124 | |
461 | L<EV::DNS>, L<EV::AnyEvent>. |
1125 | L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
1126 | event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient |
|
|
1127 | coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for |
|
|
1128 | event-loop agnostic and portable event driven programming. |
462 | |
1129 | |
463 | =head1 AUTHOR |
1130 | =head1 AUTHOR |
464 | |
1131 | |
465 | Marc Lehmann <schmorp@schmorp.de> |
1132 | Marc Lehmann <schmorp@schmorp.de> |
466 | http://home.schmorp.de/ |
1133 | http://home.schmorp.de/ |
467 | |
1134 | |
468 | =cut |
1135 | =cut |
469 | |
1136 | |