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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 { |
45 | # STAT CHANGES |
12 | warn "is called after 2s"; |
46 | my $w = EV::stat "/etc/passwd", 10, sub { |
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, $revents) = @_; |
47 | my ($w, $revents) = @_; |
42 | my $status = $w->rstatus; |
48 | warn $w->path, " has changed somehow.\n"; |
43 | }; |
49 | }; |
44 | |
50 | |
45 | # MAINLOOP |
51 | # MAINLOOP |
46 | 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 |
47 | 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 |
48 | 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 |
49 | |
55 | |
50 | =head1 DESCRIPTION |
56 | =head1 DESCRIPTION |
51 | |
57 | |
52 | This module provides an interface to libev |
58 | This module provides an interface to libev |
53 | (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. |
54 | |
76 | |
55 | =cut |
77 | =cut |
56 | |
78 | |
57 | package EV; |
79 | package EV; |
58 | |
80 | |
59 | use strict; |
81 | use common::sense; |
60 | |
82 | |
61 | BEGIN { |
83 | BEGIN { |
62 | our $VERSION = '1.2'; |
84 | our $VERSION = '3.8'; |
63 | use XSLoader; |
85 | use XSLoader; |
64 | XSLoader::load "EV", $VERSION; |
86 | XSLoader::load "EV", $VERSION; |
65 | } |
87 | } |
66 | |
88 | |
67 | @EV::Io::ISA = |
89 | @EV::IO::ISA = |
68 | @EV::Timer::ISA = |
90 | @EV::Timer::ISA = |
69 | @EV::Periodic::ISA = |
91 | @EV::Periodic::ISA = |
70 | @EV::Signal::ISA = |
92 | @EV::Signal::ISA = |
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93 | @EV::Child::ISA = |
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94 | @EV::Stat::ISA = |
71 | @EV::Idle::ISA = |
95 | @EV::Idle::ISA = |
72 | @EV::Prepare::ISA = |
96 | @EV::Prepare::ISA = |
73 | @EV::Check::ISA = |
97 | @EV::Check::ISA = |
74 | @EV::Child::ISA = "EV::Watcher"; |
98 | @EV::Embed::ISA = |
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99 | @EV::Fork::ISA = |
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100 | @EV::Async::ISA = |
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101 | "EV::Watcher"; |
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102 | |
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103 | @EV::Loop::Default::ISA = "EV::Loop"; |
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104 | |
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105 | =head1 EVENT LOOPS |
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106 | |
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107 | EV supports multiple event loops: There is a single "default event loop" |
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108 | that can handle everything including signals and child watchers, and any |
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109 | number of "dynamic event loops" that can use different backends (with |
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110 | various limitations), but no child and signal watchers. |
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111 | |
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112 | You do not have to do anything to create the default event loop: When |
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113 | the module is loaded a suitable backend is selected on the premise of |
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114 | selecting a working backend (which for example rules out kqueue on most |
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115 | BSDs). Modules should, unless they have "special needs" always use the |
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116 | default loop as this is fastest (perl-wise), best supported by other |
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117 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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118 | |
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119 | For specific programs you can create additional event loops dynamically. |
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120 | |
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121 | If you want to take advantage of kqueue (which often works properly for |
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122 | sockets only) even though the default loop doesn't enable it, you can |
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123 | I<embed> a kqueue loop into the default loop: running the default loop |
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124 | will then also service the kqueue loop to some extent. See the example in |
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125 | the section about embed watchers for an example on how to achieve that. |
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126 | |
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127 | =over 4 |
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128 | |
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129 | =item $loop = new EV::Loop [$flags] |
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130 | |
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131 | Create a new event loop as per the specified flags. Please refer to |
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132 | the C<ev_loop_new ()> function description in the libev documentation |
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133 | (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>, |
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134 | or locally-installed as F<EV::libev> manpage) for more info. |
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135 | |
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136 | The loop will automatically be destroyed when it is no longer referenced |
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137 | by any watcher and the loop object goes out of scope. |
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138 | |
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139 | If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK> |
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140 | is recommended, as only the default event loop is protected by this |
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141 | module. If you I<are> embedding this loop in the default loop, this is not |
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142 | necessary, as C<EV::embed> automatically does the right thing on fork. |
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143 | |
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144 | =item $loop->loop_fork |
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145 | |
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146 | Must be called after a fork in the child, before entering or continuing |
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147 | the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls |
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148 | this function automatically, at some performance loss (refer to the libev |
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149 | documentation). |
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150 | |
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151 | =item $loop->loop_verify |
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152 | |
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153 | Calls C<ev_verify> to make internal consistency checks (for debugging |
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154 | libev) and abort the program if any data structures were found to be |
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155 | corrupted. |
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156 | |
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157 | =item $loop = EV::default_loop [$flags] |
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158 | |
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159 | Return the default loop (which is a singleton object). Since this module |
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160 | already creates the default loop with default flags, specifying flags here |
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161 | will not have any effect unless you destroy the default loop first, which |
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162 | isn't supported. So in short: don't do it, and if you break it, you get to |
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163 | keep the pieces. |
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164 | |
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165 | =back |
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166 | |
75 | |
167 | |
76 | =head1 BASIC INTERFACE |
168 | =head1 BASIC INTERFACE |
77 | |
169 | |
78 | =over 4 |
170 | =over 4 |
79 | |
171 | |
80 | =item $EV::DIED |
172 | =item $EV::DIED |
81 | |
173 | |
82 | Must contain a reference to a function that is called when a callback |
174 | Must contain a reference to a function that is called when a callback |
83 | throws an exception (with $@ containing thr error). The default prints an |
175 | throws an exception (with $@ containing the error). The default prints an |
84 | informative message and continues. |
176 | informative message and continues. |
85 | |
177 | |
86 | If this callback throws an exception it will be silently ignored. |
178 | If this callback throws an exception it will be silently ignored. |
87 | |
179 | |
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180 | =item $flags = EV::supported_backends |
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181 | |
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182 | =item $flags = EV::recommended_backends |
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183 | |
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184 | =item $flags = EV::embeddable_backends |
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185 | |
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186 | Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this |
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187 | instance of EV, the set of recommended backends (supposed to be good) for |
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188 | this platform and the set of embeddable backends (see EMBED WATCHERS). |
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189 | |
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190 | =item EV::sleep $seconds |
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191 | |
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192 | Block the process for the given number of (fractional) seconds. |
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193 | |
88 | =item $time = EV::time |
194 | =item $time = EV::time |
89 | |
195 | |
90 | Returns the current time in (fractional) seconds since the epoch. |
196 | Returns the current time in (fractional) seconds since the epoch. |
91 | |
197 | |
92 | =item $time = EV::now |
198 | =item $time = EV::now |
93 | |
199 | |
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200 | =item $time = $loop->now |
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201 | |
94 | Returns the time the last event loop iteration has been started. This |
202 | Returns the time the last event loop iteration has been started. This |
95 | is the time that (relative) timers are based on, and refering to it is |
203 | is the time that (relative) timers are based on, and referring to it is |
96 | usually faster then calling EV::time. |
204 | usually faster then calling EV::time. |
97 | |
205 | |
98 | =item $method = EV::method |
206 | =item EV::now_update |
99 | |
207 | |
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208 | =item $loop->now_update |
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209 | |
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210 | Establishes the current time by querying the kernel, updating the time |
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211 | returned by C<EV::now> in the progress. This is a costly operation and |
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212 | is usually done automatically within C<EV::loop>. |
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213 | |
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214 | This function is rarely useful, but when some event callback runs for a |
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215 | very long time without entering the event loop, updating libev's idea of |
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216 | the current time is a good idea. |
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217 | |
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218 | =item EV::suspend |
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219 | |
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220 | =item $loop->suspend |
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221 | |
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222 | =item EV::resume |
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223 | |
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224 | =item $loop->resume |
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225 | |
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226 | These two functions suspend and resume a loop, for use when the loop is |
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227 | not used for a while and timeouts should not be processed. |
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228 | |
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229 | A typical use case would be an interactive program such as a game: When |
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230 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
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231 | would be best to handle timeouts as if no time had actually passed while |
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232 | the program was suspended. This can be achieved by calling C<suspend> |
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233 | in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling |
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234 | C<resume> directly afterwards to resume timer processing. |
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235 | |
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236 | Effectively, all C<timer> watchers will be delayed by the time spend |
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237 | between C<suspend> and C<resume>, and all C<periodic> watchers |
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238 | will be rescheduled (that is, they will lose any events that would have |
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239 | occured while suspended). |
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240 | |
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241 | After calling C<suspend> you B<must not> call I<any> function on the given |
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242 | loop other than C<resume>, and you B<must not> call C<resume> |
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243 | without a previous call to C<suspend>. |
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244 | |
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245 | Calling C<suspend>/C<resume> has the side effect of updating the event |
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246 | loop time (see C<now_update>). |
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247 | |
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248 | =item $backend = EV::backend |
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249 | |
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250 | =item $backend = $loop->backend |
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251 | |
100 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
252 | Returns an integer describing the backend used by libev (EV::BACKEND_SELECT |
101 | or EV::METHOD_EPOLL). |
253 | or EV::BACKEND_EPOLL). |
102 | |
254 | |
103 | =item EV::loop [$flags] |
255 | =item EV::loop [$flags] |
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256 | |
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257 | =item $loop->loop ([$flags]) |
104 | |
258 | |
105 | Begin checking for events and calling callbacks. It returns when a |
259 | Begin checking for events and calling callbacks. It returns when a |
106 | callback calls EV::unloop. |
260 | callback calls EV::unloop. |
107 | |
261 | |
108 | The $flags argument can be one of the following: |
262 | The $flags argument can be one of the following: |
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111 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
265 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
112 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
266 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
113 | |
267 | |
114 | =item EV::unloop [$how] |
268 | =item EV::unloop [$how] |
115 | |
269 | |
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270 | =item $loop->unloop ([$how]) |
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271 | |
116 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
272 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
117 | innermost call to EV::loop return. |
273 | innermost call to EV::loop return. |
118 | |
274 | |
119 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
275 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
120 | fast as possible. |
276 | fast as possible. |
121 | |
277 | |
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278 | =item $count = EV::loop_count |
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279 | |
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280 | =item $count = $loop->loop_count |
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281 | |
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282 | Return the number of times the event loop has polled for new |
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283 | events. Sometimes useful as a generation counter. |
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284 | |
122 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($events) |
285 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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286 | |
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287 | =item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
123 | |
288 | |
124 | This function rolls together an I/O and a timer watcher for a single |
289 | This function rolls together an I/O and a timer watcher for a single |
125 | one-shot event without the need for managing a watcher object. |
290 | one-shot event without the need for managing a watcher object. |
126 | |
291 | |
127 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
292 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
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133 | If timeout is C<undef> or negative, then there will be no |
298 | If timeout is C<undef> or negative, then there will be no |
134 | timeout. Otherwise a EV::timer with this value will be started. |
299 | timeout. Otherwise a EV::timer with this value will be started. |
135 | |
300 | |
136 | When an error occurs or either the timeout or I/O watcher triggers, then |
301 | When an error occurs or either the timeout or I/O watcher triggers, then |
137 | the callback will be called with the received event set (in general |
302 | the callback will be called with the received event set (in general |
138 | you can expect it to be a combination of C<EV:ERROR>, C<EV::READ>, |
303 | you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, |
139 | C<EV::WRITE> and C<EV::TIMEOUT>). |
304 | C<EV::WRITE> and C<EV::TIMEOUT>). |
140 | |
305 | |
141 | EV::once doesn't return anything: the watchers stay active till either |
306 | EV::once doesn't return anything: the watchers stay active till either |
142 | of them triggers, then they will be stopped and freed, and the callback |
307 | of them triggers, then they will be stopped and freed, and the callback |
143 | invoked. |
308 | invoked. |
144 | |
309 | |
145 | =back |
310 | =item EV::feed_fd_event ($fd, $revents) |
146 | |
311 | |
147 | =head2 WATCHER |
312 | =item $loop->feed_fd_event ($fd, $revents) |
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313 | |
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314 | Feed an event on a file descriptor into EV. EV will react to this call as |
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315 | if the readyness notifications specified by C<$revents> (a combination of |
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316 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
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317 | |
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318 | =item EV::feed_signal_event ($signal) |
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319 | |
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320 | Feed a signal event into EV. EV will react to this call as if the signal |
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321 | specified by C<$signal> had occured. |
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322 | |
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323 | =item EV::set_io_collect_interval $time |
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324 | |
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325 | =item $loop->set_io_collect_interval ($time) |
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326 | |
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327 | =item EV::set_timeout_collect_interval $time |
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328 | |
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329 | =item $loop->set_timeout_collect_interval ($time) |
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330 | |
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331 | These advanced functions set the minimum block interval when polling for I/O events and the minimum |
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332 | wait interval for timer events. See the libev documentation at |
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333 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> |
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334 | (locally installed as F<EV::libev>) for a more detailed discussion. |
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335 | |
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336 | =item $count = EV::pending_count |
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337 | |
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338 | =item $count = $loop->pending_count |
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339 | |
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340 | Returns the number of currently pending watchers. |
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341 | |
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342 | =item EV::invoke_pending |
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343 | |
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344 | =item $loop->invoke_pending |
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345 | |
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346 | Invoke all currently pending watchers. |
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347 | |
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348 | =back |
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349 | |
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350 | |
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351 | =head1 WATCHER OBJECTS |
148 | |
352 | |
149 | A watcher is an object that gets created to record your interest in some |
353 | A watcher is an object that gets created to record your interest in some |
150 | event. For instance, if you want to wait for STDIN to become readable, you |
354 | event. For instance, if you want to wait for STDIN to become readable, you |
151 | would create an EV::io watcher for that: |
355 | would create an EV::io watcher for that: |
152 | |
356 | |
153 | my $watcher = EV::io *STDIN, EV::READ, sub { |
357 | my $watcher = EV::io *STDIN, EV::READ, sub { |
154 | my ($watcher, $revents) = @_; |
358 | my ($watcher, $revents) = @_; |
155 | warn "yeah, STDIN should not be readable without blocking!\n" |
359 | warn "yeah, STDIN should now be readable without blocking!\n" |
156 | }; |
360 | }; |
157 | |
361 | |
158 | All watchers can be active (waiting for events) or inactive (paused). Only |
362 | All watchers can be active (waiting for events) or inactive (paused). Only |
159 | active watchers will have their callbacks invoked. All callbacks will be |
363 | active watchers will have their callbacks invoked. All callbacks will be |
160 | called with at least two arguments: the watcher and a bitmask of received |
364 | called with at least two arguments: the watcher and a bitmask of received |
161 | events. |
365 | events. |
162 | |
366 | |
163 | Each watcher type has its associated bit in revents, so you can use the |
367 | Each watcher type has its associated bit in revents, so you can use the |
164 | same callback for multiple watchers. The event mask is named after the |
368 | same callback for multiple watchers. The event mask is named after the |
165 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
369 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
166 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
370 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
167 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
371 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
168 | uses EV::TIMEOUT). |
372 | uses EV::TIMEOUT). |
169 | |
373 | |
170 | In the rare case where one wants to create a watcher but not start it at |
374 | In the rare case where one wants to create a watcher but not start it at |
171 | the same time, each constructor has a variant with a trailing C<_ns> in |
375 | the same time, each constructor has a variant with a trailing C<_ns> in |
… | |
… | |
177 | |
381 | |
178 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
382 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
179 | ->fh and so on) automatically stop and start it again if it is active, |
383 | ->fh and so on) automatically stop and start it again if it is active, |
180 | which means pending events get lost. |
384 | which means pending events get lost. |
181 | |
385 | |
182 | =head2 WATCHER TYPES |
386 | =head2 COMMON WATCHER METHODS |
183 | |
387 | |
184 | Now lets move to the existing watcher types and asociated methods. |
388 | This section lists methods common to all watchers. |
185 | |
|
|
186 | The following methods are available for all watchers. Then followes a |
|
|
187 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
|
|
188 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
|
|
189 | any type-specific methods (if any). |
|
|
190 | |
389 | |
191 | =over 4 |
390 | =over 4 |
192 | |
391 | |
193 | =item $w->start |
392 | =item $w->start |
194 | |
393 | |
… | |
… | |
198 | |
397 | |
199 | =item $w->stop |
398 | =item $w->stop |
200 | |
399 | |
201 | Stop a watcher if it is active. Also clear any pending events (events that |
400 | Stop a watcher if it is active. Also clear any pending events (events that |
202 | have been received but that didn't yet result in a callback invocation), |
401 | have been received but that didn't yet result in a callback invocation), |
203 | regardless of wether the watcher was active or not. |
402 | regardless of whether the watcher was active or not. |
204 | |
403 | |
205 | =item $bool = $w->is_active |
404 | =item $bool = $w->is_active |
206 | |
405 | |
207 | Returns true if the watcher is active, false otherwise. |
406 | Returns true if the watcher is active, false otherwise. |
208 | |
407 | |
… | |
… | |
233 | watchers with higher priority will be invoked first. The valid range of |
432 | watchers with higher priority will be invoked first. The valid range of |
234 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
433 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
235 | -2). If the priority is outside this range it will automatically be |
434 | -2). If the priority is outside this range it will automatically be |
236 | normalised to the nearest valid priority. |
435 | normalised to the nearest valid priority. |
237 | |
436 | |
238 | The default priority of any newly-created weatcher is 0. |
437 | The default priority of any newly-created watcher is 0. |
239 | |
438 | |
|
|
439 | Note that the priority semantics have not yet been fleshed out and are |
|
|
440 | subject to almost certain change. |
|
|
441 | |
240 | =item $w->trigger ($revents) |
442 | =item $w->invoke ($revents) |
241 | |
443 | |
242 | Call the callback *now* with the given event mask. |
444 | Call the callback *now* with the given event mask. |
243 | |
445 | |
|
|
446 | =item $w->feed_event ($revents) |
|
|
447 | |
|
|
448 | Feed some events on this watcher into EV. EV will react to this call as if |
|
|
449 | the watcher had received the given C<$revents> mask. |
|
|
450 | |
|
|
451 | =item $revents = $w->clear_pending |
|
|
452 | |
|
|
453 | If the watcher is pending, this function clears its pending status and |
|
|
454 | returns its C<$revents> bitset (as if its callback was invoked). If the |
|
|
455 | watcher isn't pending it does nothing and returns C<0>. |
|
|
456 | |
|
|
457 | =item $previous_state = $w->keepalive ($bool) |
|
|
458 | |
|
|
459 | Normally, C<EV::loop> will return when there are no active watchers |
|
|
460 | (which is a "deadlock" because no progress can be made anymore). This is |
|
|
461 | convinient because it allows you to start your watchers (and your jobs), |
|
|
462 | call C<EV::loop> once and when it returns you know that all your jobs are |
|
|
463 | finished (or they forgot to register some watchers for their task :). |
|
|
464 | |
|
|
465 | Sometimes, however, this gets in your way, for example when the module |
|
|
466 | that calls C<EV::loop> (usually the main program) is not the same module |
|
|
467 | as a long-living watcher (for example a DNS client module written by |
|
|
468 | somebody else even). Then you might want any outstanding requests to be |
|
|
469 | handled, but you would not want to keep C<EV::loop> from returning just |
|
|
470 | because you happen to have this long-running UDP port watcher. |
|
|
471 | |
|
|
472 | In this case you can clear the keepalive status, which means that even |
|
|
473 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
|
474 | |
|
|
475 | The initial value for keepalive is true (enabled), and you can change it |
|
|
476 | any time. |
|
|
477 | |
|
|
478 | Example: Register an I/O watcher for some UDP socket but do not keep the |
|
|
479 | event loop from running just because of that watcher. |
|
|
480 | |
|
|
481 | my $udp_socket = ... |
|
|
482 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
483 | $udp_watcher->keepalive (0); |
|
|
484 | |
|
|
485 | =item $loop = $w->loop |
|
|
486 | |
|
|
487 | Return the loop that this watcher is attached to. |
|
|
488 | |
|
|
489 | =back |
|
|
490 | |
|
|
491 | |
|
|
492 | =head1 WATCHER TYPES |
|
|
493 | |
|
|
494 | Each of the following subsections describes a single watcher type. |
|
|
495 | |
|
|
496 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
|
497 | |
|
|
498 | =over 4 |
244 | |
499 | |
245 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
500 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
246 | |
501 | |
247 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
502 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
248 | |
503 | |
|
|
504 | =item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
505 | |
|
|
506 | =item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
|
|
507 | |
249 | As long as the returned watcher object is alive, call the C<$callback> |
508 | As long as the returned watcher object is alive, call the C<$callback> |
250 | when the events specified in C<$eventmask>. |
509 | when at least one of events specified in C<$eventmask> occurs. |
251 | |
510 | |
252 | The $eventmask can be one or more of these constants ORed together: |
511 | The $eventmask can be one or more of these constants ORed together: |
253 | |
512 | |
254 | EV::READ wait until read() wouldn't block anymore |
513 | EV::READ wait until read() wouldn't block anymore |
255 | EV::WRITE wait until write() wouldn't block anymore |
514 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
271 | |
530 | |
272 | =item $old_eventmask = $w->events ($new_eventmask) |
531 | =item $old_eventmask = $w->events ($new_eventmask) |
273 | |
532 | |
274 | Returns the previously set event mask and optionally set a new one. |
533 | Returns the previously set event mask and optionally set a new one. |
275 | |
534 | |
|
|
535 | =back |
|
|
536 | |
|
|
537 | |
|
|
538 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
|
539 | |
|
|
540 | =over 4 |
276 | |
541 | |
277 | =item $w = EV::timer $after, $repeat, $callback |
542 | =item $w = EV::timer $after, $repeat, $callback |
278 | |
543 | |
279 | =item $w = EV::timer_ns $after, $repeat, $callback |
544 | =item $w = EV::timer_ns $after, $repeat, $callback |
280 | |
545 | |
281 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
546 | =item $w = $loop->timer ($after, $repeat, $callback) |
282 | the timer will be restarted (with the $repeat value as $after) after the |
547 | |
283 | callback returns. |
548 | =item $w = $loop->timer_ns ($after, $repeat, $callback) |
|
|
549 | |
|
|
550 | Calls the callback after C<$after> seconds (which may be fractional). If |
|
|
551 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
|
|
552 | value as $after) after the callback returns. |
284 | |
553 | |
285 | This means that the callback would be called roughly after C<$after> |
554 | This means that the callback would be called roughly after C<$after> |
286 | seconds, and then every C<$repeat> seconds. The timer does his best not |
555 | seconds, and then every C<$repeat> seconds. The timer does his best not |
287 | to drift, but it will not invoke the timer more often then once per event |
556 | to drift, but it will not invoke the timer more often then once per event |
288 | loop iteration, and might drift in other cases. If that isn't acceptable, |
557 | loop iteration, and might drift in other cases. If that isn't acceptable, |
… | |
… | |
294 | |
563 | |
295 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
564 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
296 | |
565 | |
297 | =item $w->set ($after, $repeat) |
566 | =item $w->set ($after, $repeat) |
298 | |
567 | |
299 | Reconfigures the watcher, see the constructor above for details. Can be at |
568 | Reconfigures the watcher, see the constructor above for details. Can be called at |
300 | any time. |
569 | any time. |
301 | |
570 | |
302 | =item $w->again |
571 | =item $w->again |
303 | |
572 | |
304 | Similar to the C<start> method, but has special semantics for repeating timers: |
573 | Similar to the C<start> method, but has special semantics for repeating timers: |
… | |
… | |
315 | This behaviour is useful when you have a timeout for some IO |
584 | This behaviour is useful when you have a timeout for some IO |
316 | operation. You create a timer object with the same value for C<$after> and |
585 | operation. You create a timer object with the same value for C<$after> and |
317 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
586 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
318 | on the timeout. |
587 | on the timeout. |
319 | |
588 | |
|
|
589 | =back |
|
|
590 | |
|
|
591 | |
|
|
592 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
593 | |
|
|
594 | =over 4 |
320 | |
595 | |
321 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
596 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
322 | |
597 | |
323 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
598 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
|
|
599 | |
|
|
600 | =item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
|
|
601 | |
|
|
602 | =item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
324 | |
603 | |
325 | Similar to EV::timer, but is not based on relative timeouts but on |
604 | Similar to EV::timer, but is not based on relative timeouts but on |
326 | absolute times. Apart from creating "simple" timers that trigger "at" the |
605 | absolute times. Apart from creating "simple" timers that trigger "at" the |
327 | specified time, it can also be used for non-drifting absolute timers and |
606 | specified time, it can also be used for non-drifting absolute timers and |
328 | more complex, cron-like, setups that are not adversely affected by time |
607 | more complex, cron-like, setups that are not adversely affected by time |
… | |
… | |
338 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
617 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
339 | will not adjust when a time jump occurs, that is, if it is to be run |
618 | will not adjust when a time jump occurs, that is, if it is to be run |
340 | at January 1st 2011 then it will run when the system time reaches or |
619 | at January 1st 2011 then it will run when the system time reaches or |
341 | surpasses this time. |
620 | surpasses this time. |
342 | |
621 | |
343 | =item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
622 | =item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
344 | |
623 | |
345 | In this mode the watcher will always be scheduled to time out at the |
624 | In this mode the watcher will always be scheduled to time out at the |
346 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
625 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
347 | regardless of any time jumps. |
626 | regardless of any time jumps. |
348 | |
627 | |
… | |
… | |
366 | time the periodic watcher gets scheduled, the reschedule callback |
645 | time the periodic watcher gets scheduled, the reschedule callback |
367 | ($reschedule_cb) will be called with the watcher as first, and the current |
646 | ($reschedule_cb) will be called with the watcher as first, and the current |
368 | time as second argument. |
647 | time as second argument. |
369 | |
648 | |
370 | I<This callback MUST NOT stop or destroy this or any other periodic |
649 | I<This callback MUST NOT stop or destroy this or any other periodic |
371 | watcher, ever>. If you need to stop it, return 1e30 and stop it |
650 | watcher, ever, and MUST NOT call any event loop functions or methods>. If |
372 | afterwards. |
651 | you need to stop it, return 1e30 and stop it afterwards. You may create |
|
|
652 | and start a C<EV::prepare> watcher for this task. |
373 | |
653 | |
374 | It must return the next time to trigger, based on the passed time value |
654 | It must return the next time to trigger, based on the passed time value |
375 | (that is, the lowest time value larger than to the second argument). It |
655 | (that is, the lowest time value larger than or equal to to the second |
376 | will usually be called just before the callback will be triggered, but |
656 | argument). It will usually be called just before the callback will be |
377 | might be called at other times, too. |
657 | triggered, but might be called at other times, too. |
378 | |
658 | |
379 | This can be used to create very complex timers, such as a timer that |
659 | This can be used to create very complex timers, such as a timer that |
380 | triggers on each midnight, local time (actually 24 hours after the last |
660 | triggers on each midnight, local time (actually 24 hours after the last |
381 | midnight, to keep the example simple. If you know a way to do it correctly |
661 | midnight, to keep the example simple. If you know a way to do it correctly |
382 | in about the same space (without requiring elaborate modules), drop me a |
662 | in about the same space (without requiring elaborate modules), drop me a |
… | |
… | |
396 | |
676 | |
397 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
677 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
398 | |
678 | |
399 | =item $w->set ($at, $interval, $reschedule_cb) |
679 | =item $w->set ($at, $interval, $reschedule_cb) |
400 | |
680 | |
401 | Reconfigures the watcher, see the constructor above for details. Can be at |
681 | Reconfigures the watcher, see the constructor above for details. Can be called at |
402 | any time. |
682 | any time. |
403 | |
683 | |
404 | =item $w->again |
684 | =item $w->again |
405 | |
685 | |
406 | Simply stops and starts the watcher again. |
686 | Simply stops and starts the watcher again. |
407 | |
687 | |
|
|
688 | =item $time = $w->at |
|
|
689 | |
|
|
690 | Return the time that the watcher is expected to trigger next. |
|
|
691 | |
|
|
692 | =back |
|
|
693 | |
|
|
694 | |
|
|
695 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
696 | |
|
|
697 | =over 4 |
408 | |
698 | |
409 | =item $w = EV::signal $signal, $callback |
699 | =item $w = EV::signal $signal, $callback |
410 | |
700 | |
411 | =item $w = EV::signal_ns $signal, $callback |
701 | =item $w = EV::signal_ns $signal, $callback |
412 | |
702 | |
413 | Call the callback when $signal is received (the signal can be specified |
703 | Call the callback when $signal is received (the signal can be specified by |
414 | by number or by name, just as with kill or %SIG). |
704 | number or by name, just as with C<kill> or C<%SIG>). |
415 | |
705 | |
416 | EV will grab the signal for the process (the kernel only allows one |
706 | EV will grab the signal for the process (the kernel only allows one |
417 | component to receive a signal at a time) when you start a signal watcher, |
707 | component to receive a signal at a time) when you start a signal watcher, |
418 | and removes it again when you stop it. Perl does the same when you |
708 | and removes it again when you stop it. Perl does the same when you |
419 | add/remove callbacks to %SIG, so watch out. |
709 | add/remove callbacks to C<%SIG>, so watch out. |
420 | |
710 | |
421 | You can have as many signal watchers per signal as you want. |
711 | You can have as many signal watchers per signal as you want. |
422 | |
712 | |
423 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
713 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
424 | |
714 | |
425 | =item $w->set ($signal) |
715 | =item $w->set ($signal) |
426 | |
716 | |
427 | Reconfigures the watcher, see the constructor above for details. Can be at |
717 | Reconfigures the watcher, see the constructor above for details. Can be |
428 | any time. |
718 | called at any time. |
429 | |
719 | |
430 | =item $current_signum = $w->signal |
720 | =item $current_signum = $w->signal |
431 | |
721 | |
432 | =item $old_signum = $w->signal ($new_signal) |
722 | =item $old_signum = $w->signal ($new_signal) |
433 | |
723 | |
434 | Returns the previously set signal (always as a number not name) and |
724 | Returns the previously set signal (always as a number not name) and |
435 | optionally set a new one. |
725 | optionally set a new one. |
436 | |
726 | |
|
|
727 | =back |
437 | |
728 | |
|
|
729 | |
|
|
730 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
731 | |
|
|
732 | =over 4 |
|
|
733 | |
438 | =item $w = EV::child $pid, $callback |
734 | =item $w = EV::child $pid, $trace, $callback |
439 | |
735 | |
440 | =item $w = EV::child_ns $pid, $callback |
736 | =item $w = EV::child_ns $pid, $trace, $callback |
|
|
737 | |
|
|
738 | =item $w = $loop->child ($pid, $trace, $callback) |
|
|
739 | |
|
|
740 | =item $w = $loop->child_ns ($pid, $trace, $callback) |
441 | |
741 | |
442 | Call the callback when a status change for pid C<$pid> (or any pid |
742 | Call the callback when a status change for pid C<$pid> (or any pid |
443 | if C<$pid> is 0) has been received. More precisely: when the process |
743 | if C<$pid> is 0) has been received (a status change happens when the |
|
|
744 | process terminates or is killed, or, when trace is true, additionally when |
|
|
745 | it is stopped or continued). More precisely: when the process receives |
444 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
746 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
445 | changed/zombie children and call the callback. |
747 | changed/zombie children and call the callback. |
446 | |
748 | |
447 | You can access both status and pid by using the C<rstatus> and C<rpid> |
749 | It is valid (and fully supported) to install a child watcher after a child |
448 | methods on the watcher object. |
750 | has exited but before the event loop has started its next iteration (for |
|
|
751 | example, first you C<fork>, then the new child process might exit, and |
|
|
752 | only then do you install a child watcher in the parent for the new pid). |
449 | |
753 | |
|
|
754 | You can access both exit (or tracing) status and pid by using the |
|
|
755 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
756 | |
450 | You can have as many pid watchers per pid as you want. |
757 | You can have as many pid watchers per pid as you want, they will all be |
|
|
758 | called. |
451 | |
759 | |
452 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
760 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
453 | |
761 | |
454 | =item $w->set ($pid) |
762 | =item $w->set ($pid, $trace) |
455 | |
763 | |
456 | Reconfigures the watcher, see the constructor above for details. Can be at |
764 | Reconfigures the watcher, see the constructor above for details. Can be called at |
457 | any time. |
765 | any time. |
458 | |
766 | |
459 | =item $current_pid = $w->pid |
767 | =item $current_pid = $w->pid |
460 | |
|
|
461 | =item $old_pid = $w->pid ($new_pid) |
|
|
462 | |
768 | |
463 | Returns the previously set process id and optionally set a new one. |
769 | Returns the previously set process id and optionally set a new one. |
464 | |
770 | |
465 | =item $exit_status = $w->rstatus |
771 | =item $exit_status = $w->rstatus |
466 | |
772 | |
… | |
… | |
470 | =item $pid = $w->rpid |
776 | =item $pid = $w->rpid |
471 | |
777 | |
472 | Return the pid of the awaited child (useful when you have installed a |
778 | Return the pid of the awaited child (useful when you have installed a |
473 | watcher for all pids). |
779 | watcher for all pids). |
474 | |
780 | |
|
|
781 | =back |
|
|
782 | |
|
|
783 | |
|
|
784 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
785 | |
|
|
786 | =over 4 |
|
|
787 | |
|
|
788 | =item $w = EV::stat $path, $interval, $callback |
|
|
789 | |
|
|
790 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
791 | |
|
|
792 | =item $w = $loop->stat ($path, $interval, $callback) |
|
|
793 | |
|
|
794 | =item $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
795 | |
|
|
796 | Call the callback when a file status change has been detected on |
|
|
797 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
798 | to "path does not exist" is a status change like any other. |
|
|
799 | |
|
|
800 | The C<$interval> is a recommended polling interval for systems where |
|
|
801 | OS-supported change notifications don't exist or are not supported. If |
|
|
802 | you use C<0> then an unspecified default is used (which is highly |
|
|
803 | recommended!), which is to be expected to be around five seconds usually. |
|
|
804 | |
|
|
805 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
806 | as even with OS-supported change notifications, this can be |
|
|
807 | resource-intensive. |
|
|
808 | |
|
|
809 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
810 | |
|
|
811 | =item ... = $w->stat |
|
|
812 | |
|
|
813 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
814 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
815 | well as EV's idea of the current stat values) to the values found. |
|
|
816 | |
|
|
817 | In scalar context, a boolean is return indicating success or failure of |
|
|
818 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
819 | (except that the blksize and blocks fields are not reliable). |
|
|
820 | |
|
|
821 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
822 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
823 | was successful then nlink is guaranteed to be non-zero). |
|
|
824 | |
|
|
825 | See also the next two entries for more info. |
|
|
826 | |
|
|
827 | =item ... = $w->attr |
|
|
828 | |
|
|
829 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
830 | the values most recently detected by EV. See the next entry for more info. |
|
|
831 | |
|
|
832 | =item ... = $w->prev |
|
|
833 | |
|
|
834 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
835 | the previous set of values, before the change. |
|
|
836 | |
|
|
837 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
838 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
839 | returns the values found leading to the change detection. The difference (if any) |
|
|
840 | between C<prev> and C<attr> is what triggered the callback. |
|
|
841 | |
|
|
842 | If you did something to the filesystem object and do not want to trigger |
|
|
843 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
844 | current attributes are. |
|
|
845 | |
|
|
846 | =item $w->set ($path, $interval) |
|
|
847 | |
|
|
848 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
849 | called at any time. |
|
|
850 | |
|
|
851 | =item $current_path = $w->path |
|
|
852 | |
|
|
853 | =item $old_path = $w->path ($new_path) |
|
|
854 | |
|
|
855 | Returns the previously set path and optionally set a new one. |
|
|
856 | |
|
|
857 | =item $current_interval = $w->interval |
|
|
858 | |
|
|
859 | =item $old_interval = $w->interval ($new_interval) |
|
|
860 | |
|
|
861 | Returns the previously set interval and optionally set a new one. Can be |
|
|
862 | used to query the actual interval used. |
|
|
863 | |
|
|
864 | =back |
|
|
865 | |
|
|
866 | |
|
|
867 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
868 | |
|
|
869 | =over 4 |
475 | |
870 | |
476 | =item $w = EV::idle $callback |
871 | =item $w = EV::idle $callback |
477 | |
872 | |
478 | =item $w = EV::idle_ns $callback |
873 | =item $w = EV::idle_ns $callback |
479 | |
874 | |
480 | Call the callback when there are no pending io, timer/periodic, signal or |
875 | =item $w = $loop->idle ($callback) |
481 | child events, i.e. when the process is idle. |
876 | |
|
|
877 | =item $w = $loop->idle_ns ($callback) |
|
|
878 | |
|
|
879 | Call the callback when there are no other pending watchers of the same or |
|
|
880 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
881 | same or lower priority, of course). They are called idle watchers because |
|
|
882 | when the watcher is the highest priority pending event in the process, the |
|
|
883 | process is considered to be idle at that priority. |
|
|
884 | |
|
|
885 | If you want a watcher that is only ever called when I<no> other events are |
|
|
886 | outstanding you have to set the priority to C<EV::MINPRI>. |
482 | |
887 | |
483 | The process will not block as long as any idle watchers are active, and |
888 | The process will not block as long as any idle watchers are active, and |
484 | they will be called repeatedly until stopped. |
889 | they will be called repeatedly until stopped. |
485 | |
890 | |
|
|
891 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
892 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
893 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
894 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
895 | pending with the C<0>-priority idle watcher be invoked. |
|
|
896 | |
486 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
897 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
487 | |
898 | |
|
|
899 | =back |
|
|
900 | |
|
|
901 | |
|
|
902 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
903 | |
|
|
904 | =over 4 |
488 | |
905 | |
489 | =item $w = EV::prepare $callback |
906 | =item $w = EV::prepare $callback |
490 | |
907 | |
491 | =item $w = EV::prepare_ns $callback |
908 | =item $w = EV::prepare_ns $callback |
|
|
909 | |
|
|
910 | =item $w = $loop->prepare ($callback) |
|
|
911 | |
|
|
912 | =item $w = $loop->prepare_ns ($callback) |
492 | |
913 | |
493 | Call the callback just before the process would block. You can still |
914 | Call the callback just before the process would block. You can still |
494 | create/modify any watchers at this point. |
915 | create/modify any watchers at this point. |
495 | |
916 | |
496 | See the EV::check watcher, below, for explanations and an example. |
917 | See the EV::check watcher, below, for explanations and an example. |
497 | |
918 | |
498 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
919 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
499 | |
920 | |
|
|
921 | =back |
|
|
922 | |
|
|
923 | |
|
|
924 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
925 | |
|
|
926 | =over 4 |
500 | |
927 | |
501 | =item $w = EV::check $callback |
928 | =item $w = EV::check $callback |
502 | |
929 | |
503 | =item $w = EV::check_ns $callback |
930 | =item $w = EV::check_ns $callback |
|
|
931 | |
|
|
932 | =item $w = $loop->check ($callback) |
|
|
933 | |
|
|
934 | =item $w = $loop->check_ns ($callback) |
504 | |
935 | |
505 | Call the callback just after the process wakes up again (after it has |
936 | Call the callback just after the process wakes up again (after it has |
506 | gathered events), but before any other callbacks have been invoked. |
937 | gathered events), but before any other callbacks have been invoked. |
507 | |
938 | |
508 | This is used to integrate other event-based software into the EV |
939 | This is used to integrate other event-based software into the EV |
… | |
… | |
518 | or return; |
949 | or return; |
519 | |
950 | |
520 | # make the dispatcher handle any outstanding stuff |
951 | # make the dispatcher handle any outstanding stuff |
521 | ... not shown |
952 | ... not shown |
522 | |
953 | |
523 | # create an IO watcher for each and every socket |
954 | # create an I/O watcher for each and every socket |
524 | @snmp_watcher = ( |
955 | @snmp_watcher = ( |
525 | (map { EV::io $_, EV::READ, sub { } } |
956 | (map { EV::io $_, EV::READ, sub { } } |
526 | keys %{ $dispatcher->{_descriptors} }), |
957 | keys %{ $dispatcher->{_descriptors} }), |
527 | |
958 | |
528 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
959 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
… | |
… | |
543 | # make the dispatcher handle any new stuff |
974 | # make the dispatcher handle any new stuff |
544 | ... not shown |
975 | ... not shown |
545 | }; |
976 | }; |
546 | |
977 | |
547 | The callbacks of the created watchers will not be called as the watchers |
978 | The callbacks of the created watchers will not be called as the watchers |
548 | are destroyed before this cna happen (remember EV::check gets called |
979 | are destroyed before this can happen (remember EV::check gets called |
549 | first). |
980 | first). |
550 | |
981 | |
551 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
982 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
552 | |
983 | |
553 | =back |
984 | =back |
554 | |
985 | |
|
|
986 | |
|
|
987 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
988 | |
|
|
989 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
990 | is done before the event loop blocks next and before C<check> watchers |
|
|
991 | are being called, and only in the child after the fork. |
|
|
992 | |
|
|
993 | =over 4 |
|
|
994 | |
|
|
995 | =item $w = EV::fork $callback |
|
|
996 | |
|
|
997 | =item $w = EV::fork_ns $callback |
|
|
998 | |
|
|
999 | =item $w = $loop->fork ($callback) |
|
|
1000 | |
|
|
1001 | =item $w = $loop->fork_ns ($callback) |
|
|
1002 | |
|
|
1003 | Call the callback before the event loop is resumed in the child process |
|
|
1004 | after a fork. |
|
|
1005 | |
|
|
1006 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
1007 | |
|
|
1008 | =back |
|
|
1009 | |
|
|
1010 | |
|
|
1011 | =head3 EMBED WATCHERS - when one backend isn't enough... |
|
|
1012 | |
|
|
1013 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1014 | into another (currently only IO events are supported in the embedded |
|
|
1015 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1016 | fashion and must not be used). |
|
|
1017 | |
|
|
1018 | See the libev documentation at |
|
|
1019 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> |
|
|
1020 | (locally installed as F<EV::libev>) for more details. |
|
|
1021 | |
|
|
1022 | In short, this watcher is most useful on BSD systems without working |
|
|
1023 | kqueue to still be able to handle a large number of sockets: |
|
|
1024 | |
|
|
1025 | my $socket_loop; |
|
|
1026 | |
|
|
1027 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
1028 | if ( |
|
|
1029 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
1030 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
1031 | ) { |
|
|
1032 | # use kqueue for sockets |
|
|
1033 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
1034 | } |
|
|
1035 | |
|
|
1036 | # use the default loop otherwise |
|
|
1037 | $socket_loop ||= EV::default_loop; |
|
|
1038 | |
|
|
1039 | =over 4 |
|
|
1040 | |
|
|
1041 | =item $w = EV::embed $otherloop[, $callback] |
|
|
1042 | |
|
|
1043 | =item $w = EV::embed_ns $otherloop[, $callback] |
|
|
1044 | |
|
|
1045 | =item $w = $loop->embed ($otherloop[, $callback]) |
|
|
1046 | |
|
|
1047 | =item $w = $loop->embed_ns ($otherloop[, $callback]) |
|
|
1048 | |
|
|
1049 | Call the callback when the embedded event loop (C<$otherloop>) has any |
|
|
1050 | I/O activity. The C<$callback> is optional: if it is missing, then the |
|
|
1051 | embedded event loop will be managed automatically (which is recommended), |
|
|
1052 | otherwise you have to invoke C<sweep> yourself. |
|
|
1053 | |
|
|
1054 | The C<embed_ns> variant doesn't start (activate) the newly created watcher. |
|
|
1055 | |
|
|
1056 | =back |
|
|
1057 | |
|
|
1058 | =head3 ASYNC WATCHERS - how to wake up another event loop |
|
|
1059 | |
|
|
1060 | Async watchers are provided by EV, but have little use in perl directly, |
|
|
1061 | as perl neither supports threads running in parallel nor direct access to |
|
|
1062 | signal handlers or other contexts where they could be of value. |
|
|
1063 | |
|
|
1064 | It is, however, possible to use them from the XS level. |
|
|
1065 | |
|
|
1066 | Please see the libev documentation for further details. |
|
|
1067 | |
|
|
1068 | =over 4 |
|
|
1069 | |
|
|
1070 | =item $w = EV::async $callback |
|
|
1071 | |
|
|
1072 | =item $w = EV::async_ns $callback |
|
|
1073 | |
|
|
1074 | =item $w->send |
|
|
1075 | |
|
|
1076 | =item $bool = $w->async_pending |
|
|
1077 | |
|
|
1078 | =back |
|
|
1079 | |
|
|
1080 | |
|
|
1081 | =head1 PERL SIGNALS |
|
|
1082 | |
|
|
1083 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
1084 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
1085 | handled when Perl runs, which means your signal handler might be invoked |
|
|
1086 | only the next time an event callback is invoked. |
|
|
1087 | |
|
|
1088 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
1089 | ensure proper operations with regards to other event watchers. |
|
|
1090 | |
|
|
1091 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
1092 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
1093 | watcher: |
|
|
1094 | |
|
|
1095 | my $async_check = EV::check sub { }; |
|
|
1096 | |
|
|
1097 | This ensures that perl gets into control for a short time to handle any |
|
|
1098 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
1099 | |
555 | =head1 THREADS |
1100 | =head1 ITHREADS |
556 | |
1101 | |
557 | Threads are not supported by this module in any way. Perl pseudo-threads |
1102 | Ithreads are not supported by this module in any way. Perl pseudo-threads |
558 | is evil stuff and must die. As soon as Perl gains real threads I will work |
1103 | is evil stuff and must die. Real threads as provided by Coro are fully |
559 | on thread support for it. |
1104 | supported (and enhanced support is available via L<Coro::EV>). |
560 | |
1105 | |
561 | =head1 FORK |
1106 | =head1 FORK |
562 | |
1107 | |
563 | Most of the "improved" event delivering mechanisms of modern operating |
1108 | Most of the "improved" event delivering mechanisms of modern operating |
564 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
1109 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
… | |
… | |
580 | our $DIED = sub { |
1125 | our $DIED = sub { |
581 | warn "EV: error in callback (ignoring): $@"; |
1126 | warn "EV: error in callback (ignoring): $@"; |
582 | }; |
1127 | }; |
583 | |
1128 | |
584 | default_loop |
1129 | default_loop |
585 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
1130 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
586 | |
1131 | |
587 | 1; |
1132 | 1; |
588 | |
1133 | |
589 | =head1 SEE ALSO |
1134 | =head1 SEE ALSO |
590 | |
1135 | |
591 | L<EV::DNS>. |
1136 | L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
1137 | event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient |
|
|
1138 | coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for |
|
|
1139 | event-loop agnostic and portable event driven programming. |
592 | |
1140 | |
593 | =head1 AUTHOR |
1141 | =head1 AUTHOR |
594 | |
1142 | |
595 | Marc Lehmann <schmorp@schmorp.de> |
1143 | Marc Lehmann <schmorp@schmorp.de> |
596 | http://home.schmorp.de/ |
1144 | http://home.schmorp.de/ |
597 | |
1145 | |
598 | =cut |
1146 | =cut |
599 | |
1147 | |