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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 |
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55 | |
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56 | =head1 BEFORE YOU START USING THIS MODULE |
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57 | |
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58 | If you only need timer, I/O, signal, child and idle watchers and not the |
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59 | advanced functionality of this module, consider using L<AnyEvent> instead, |
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60 | specifically the simplified API described in L<AE>. |
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61 | |
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62 | When used with EV as backend, the L<AE> API is as fast as the native L<EV> |
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63 | API, but your programs/modules will still run with many other event loops. |
49 | |
64 | |
50 | =head1 DESCRIPTION |
65 | =head1 DESCRIPTION |
51 | |
66 | |
52 | This module provides an interface to libev |
67 | This module provides an interface to libev |
53 | (L<http://software.schmorp.de/pkg/libev.html>). |
68 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
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69 | below is comprehensive, one might also consult the documentation of |
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70 | libev itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or |
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71 | F<perldoc EV::libev>) for more subtle details on watcher semantics or some |
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72 | discussion on the available backends, or how to force a specific backend |
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73 | with C<LIBEV_FLAGS>, or just about in any case because it has much more |
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74 | detailed information. |
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75 | |
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76 | This module is very fast and scalable. It is actually so fast that you |
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77 | can use it through the L<AnyEvent> module, stay portable to other event |
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78 | loops (if you don't rely on any watcher types not available through it) |
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79 | and still be faster than with any other event loop currently supported in |
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80 | Perl. |
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81 | |
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82 | =head2 MODULE EXPORTS |
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83 | |
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84 | This module does not export any symbols. |
54 | |
85 | |
55 | =cut |
86 | =cut |
56 | |
87 | |
57 | package EV; |
88 | package EV; |
58 | |
89 | |
59 | use strict; |
90 | use common::sense; |
60 | |
91 | |
61 | BEGIN { |
92 | BEGIN { |
62 | our $VERSION = '1.2'; |
93 | our $VERSION = '4.00'; |
63 | use XSLoader; |
94 | use XSLoader; |
64 | XSLoader::load "EV", $VERSION; |
95 | XSLoader::load "EV", $VERSION; |
65 | } |
96 | } |
66 | |
97 | |
67 | @EV::Io::ISA = |
98 | @EV::IO::ISA = |
68 | @EV::Timer::ISA = |
99 | @EV::Timer::ISA = |
69 | @EV::Periodic::ISA = |
100 | @EV::Periodic::ISA = |
70 | @EV::Signal::ISA = |
101 | @EV::Signal::ISA = |
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102 | @EV::Child::ISA = |
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103 | @EV::Stat::ISA = |
71 | @EV::Idle::ISA = |
104 | @EV::Idle::ISA = |
72 | @EV::Prepare::ISA = |
105 | @EV::Prepare::ISA = |
73 | @EV::Check::ISA = |
106 | @EV::Check::ISA = |
74 | @EV::Child::ISA = "EV::Watcher"; |
107 | @EV::Embed::ISA = |
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108 | @EV::Fork::ISA = |
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109 | @EV::Async::ISA = |
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110 | "EV::Watcher"; |
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111 | |
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112 | @EV::Loop::Default::ISA = "EV::Loop"; |
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113 | |
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114 | =head1 EVENT LOOPS |
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115 | |
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116 | EV supports multiple event loops: There is a single "default event loop" |
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117 | that can handle everything including signals and child watchers, and any |
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118 | number of "dynamic event loops" that can use different backends (with |
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119 | various limitations), but no child and signal watchers. |
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120 | |
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121 | You do not have to do anything to create the default event loop: When |
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122 | the module is loaded a suitable backend is selected on the premise of |
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123 | selecting a working backend (which for example rules out kqueue on most |
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124 | BSDs). Modules should, unless they have "special needs" always use the |
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125 | default loop as this is fastest (perl-wise), best supported by other |
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126 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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127 | |
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128 | For specific programs you can create additional event loops dynamically. |
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129 | |
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130 | If you want to take advantage of kqueue (which often works properly for |
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131 | sockets only) even though the default loop doesn't enable it, you can |
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132 | I<embed> a kqueue loop into the default loop: running the default loop |
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133 | will then also service the kqueue loop to some extent. See the example in |
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134 | the section about embed watchers for an example on how to achieve that. |
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135 | |
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136 | =over 4 |
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137 | |
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138 | =item $loop = new EV::Loop [$flags] |
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139 | |
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140 | Create a new event loop as per the specified flags. Please refer to |
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141 | the C<ev_loop_new ()> function description in the libev documentation |
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142 | (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>, |
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143 | or locally-installed as F<EV::libev> manpage) for more info. |
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144 | |
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145 | The loop will automatically be destroyed when it is no longer referenced |
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146 | by any watcher and the loop object goes out of scope. |
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147 | |
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148 | If you are not embedding the loop, then Using C<EV::FLAG_FORKCHECK> |
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149 | is recommended, as only the default event loop is protected by this |
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150 | module. If you I<are> embedding this loop in the default loop, this is not |
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151 | necessary, as C<EV::embed> automatically does the right thing on fork. |
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152 | |
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153 | =item $loop->loop_fork |
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154 | |
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155 | Must be called after a fork in the child, before entering or continuing |
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156 | the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls |
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157 | this function automatically, at some performance loss (refer to the libev |
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158 | documentation). |
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159 | |
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160 | =item $loop->loop_verify |
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161 | |
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162 | Calls C<ev_verify> to make internal consistency checks (for debugging |
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163 | libev) and abort the program if any data structures were found to be |
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164 | corrupted. |
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165 | |
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166 | =item $loop = EV::default_loop [$flags] |
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167 | |
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168 | Return the default loop (which is a singleton object). Since this module |
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169 | already creates the default loop with default flags, specifying flags here |
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170 | will not have any effect unless you destroy the default loop first, which |
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171 | isn't supported. So in short: don't do it, and if you break it, you get to |
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172 | keep the pieces. |
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173 | |
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174 | =back |
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175 | |
75 | |
176 | |
76 | =head1 BASIC INTERFACE |
177 | =head1 BASIC INTERFACE |
77 | |
178 | |
78 | =over 4 |
179 | =over 4 |
79 | |
180 | |
80 | =item $EV::DIED |
181 | =item $EV::DIED |
81 | |
182 | |
82 | Must contain a reference to a function that is called when a callback |
183 | Must contain a reference to a function that is called when a callback |
83 | throws an exception (with $@ containing thr error). The default prints an |
184 | throws an exception (with $@ containing the error). The default prints an |
84 | informative message and continues. |
185 | informative message and continues. |
85 | |
186 | |
86 | If this callback throws an exception it will be silently ignored. |
187 | If this callback throws an exception it will be silently ignored. |
87 | |
188 | |
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189 | =item $flags = EV::supported_backends |
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190 | |
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191 | =item $flags = EV::recommended_backends |
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192 | |
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193 | =item $flags = EV::embeddable_backends |
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194 | |
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195 | Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this |
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196 | instance of EV, the set of recommended backends (supposed to be good) for |
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197 | this platform and the set of embeddable backends (see EMBED WATCHERS). |
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198 | |
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199 | =item EV::sleep $seconds |
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200 | |
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201 | Block the process for the given number of (fractional) seconds. |
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202 | |
88 | =item $time = EV::time |
203 | =item $time = EV::time |
89 | |
204 | |
90 | Returns the current time in (fractional) seconds since the epoch. |
205 | Returns the current time in (fractional) seconds since the epoch. |
91 | |
206 | |
92 | =item $time = EV::now |
207 | =item $time = EV::now |
93 | |
208 | |
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209 | =item $time = $loop->now |
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210 | |
94 | Returns the time the last event loop iteration has been started. This |
211 | Returns the time the last event loop iteration has been started. This |
95 | is the time that (relative) timers are based on, and refering to it is |
212 | is the time that (relative) timers are based on, and referring to it is |
96 | usually faster then calling EV::time. |
213 | usually faster then calling EV::time. |
97 | |
214 | |
98 | =item $method = EV::method |
215 | =item EV::now_update |
99 | |
216 | |
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217 | =item $loop->now_update |
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218 | |
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219 | Establishes the current time by querying the kernel, updating the time |
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220 | returned by C<EV::now> in the progress. This is a costly operation and |
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221 | is usually done automatically within C<EV::loop>. |
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222 | |
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223 | This function is rarely useful, but when some event callback runs for a |
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224 | very long time without entering the event loop, updating libev's idea of |
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225 | the current time is a good idea. |
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226 | |
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227 | =item EV::suspend |
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228 | |
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229 | =item $loop->suspend |
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230 | |
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231 | =item EV::resume |
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232 | |
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233 | =item $loop->resume |
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234 | |
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235 | These two functions suspend and resume a loop, for use when the loop is |
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236 | not used for a while and timeouts should not be processed. |
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237 | |
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238 | A typical use case would be an interactive program such as a game: When |
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239 | the user presses C<^Z> to suspend the game and resumes it an hour later it |
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240 | would be best to handle timeouts as if no time had actually passed while |
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241 | the program was suspended. This can be achieved by calling C<suspend> |
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242 | in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling |
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243 | C<resume> directly afterwards to resume timer processing. |
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244 | |
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245 | Effectively, all C<timer> watchers will be delayed by the time spend |
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246 | between C<suspend> and C<resume>, and all C<periodic> watchers |
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247 | will be rescheduled (that is, they will lose any events that would have |
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248 | occured while suspended). |
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249 | |
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250 | After calling C<suspend> you B<must not> call I<any> function on the given |
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251 | loop other than C<resume>, and you B<must not> call C<resume> |
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252 | without a previous call to C<suspend>. |
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253 | |
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254 | Calling C<suspend>/C<resume> has the side effect of updating the event |
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255 | loop time (see C<now_update>). |
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256 | |
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257 | =item $backend = EV::backend |
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258 | |
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259 | =item $backend = $loop->backend |
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260 | |
100 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
261 | Returns an integer describing the backend used by libev (EV::BACKEND_SELECT |
101 | or EV::METHOD_EPOLL). |
262 | or EV::BACKEND_EPOLL). |
102 | |
263 | |
103 | =item EV::loop [$flags] |
264 | =item EV::loop [$flags] |
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265 | |
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266 | =item $loop->loop ([$flags]) |
104 | |
267 | |
105 | Begin checking for events and calling callbacks. It returns when a |
268 | Begin checking for events and calling callbacks. It returns when a |
106 | callback calls EV::unloop. |
269 | callback calls EV::unloop. |
107 | |
270 | |
108 | The $flags argument can be one of the following: |
271 | The $flags argument can be one of the following: |
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111 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
274 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
112 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
275 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
113 | |
276 | |
114 | =item EV::unloop [$how] |
277 | =item EV::unloop [$how] |
115 | |
278 | |
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279 | =item $loop->unloop ([$how]) |
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280 | |
116 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
281 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
117 | innermost call to EV::loop return. |
282 | innermost call to EV::loop return. |
118 | |
283 | |
119 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
284 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
120 | fast as possible. |
285 | fast as possible. |
121 | |
286 | |
122 | =back |
287 | =item $count = EV::loop_count |
123 | |
288 | |
124 | =head2 WATCHER |
289 | =item $count = $loop->loop_count |
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290 | |
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291 | Return the number of times the event loop has polled for new |
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292 | events. Sometimes useful as a generation counter. |
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293 | |
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294 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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295 | |
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296 | =item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
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297 | |
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298 | This function rolls together an I/O and a timer watcher for a single |
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299 | one-shot event without the need for managing a watcher object. |
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300 | |
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301 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
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302 | must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
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303 | | EV::WRITE>, indicating the type of I/O event you want to wait for. If |
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304 | you do not want to wait for some I/O event, specify C<undef> for |
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305 | C<$fh_or_undef> and C<0> for C<$events>). |
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306 | |
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307 | If timeout is C<undef> or negative, then there will be no |
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308 | timeout. Otherwise a EV::timer with this value will be started. |
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309 | |
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310 | When an error occurs or either the timeout or I/O watcher triggers, then |
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311 | the callback will be called with the received event set (in general |
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312 | you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, |
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313 | C<EV::WRITE> and C<EV::TIMER>). |
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314 | |
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315 | EV::once doesn't return anything: the watchers stay active till either |
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316 | of them triggers, then they will be stopped and freed, and the callback |
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317 | invoked. |
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318 | |
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319 | =item EV::feed_fd_event ($fd, $revents) |
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320 | |
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321 | =item $loop->feed_fd_event ($fd, $revents) |
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322 | |
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323 | Feed an event on a file descriptor into EV. EV will react to this call as |
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324 | if the readyness notifications specified by C<$revents> (a combination of |
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325 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
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326 | |
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327 | =item EV::feed_signal_event ($signal) |
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328 | |
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329 | Feed a signal event into EV. EV will react to this call as if the signal |
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330 | specified by C<$signal> had occured. |
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331 | |
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332 | =item EV::set_io_collect_interval $time |
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333 | |
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334 | =item $loop->set_io_collect_interval ($time) |
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335 | |
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336 | =item EV::set_timeout_collect_interval $time |
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337 | |
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338 | =item $loop->set_timeout_collect_interval ($time) |
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339 | |
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340 | These advanced functions set the minimum block interval when polling for I/O events and the minimum |
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341 | wait interval for timer events. See the libev documentation at |
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342 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> |
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343 | (locally installed as F<EV::libev>) for a more detailed discussion. |
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344 | |
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345 | =item $count = EV::pending_count |
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346 | |
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347 | =item $count = $loop->pending_count |
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348 | |
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349 | Returns the number of currently pending watchers. |
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350 | |
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351 | =item EV::invoke_pending |
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352 | |
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353 | =item $loop->invoke_pending |
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354 | |
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355 | Invoke all currently pending watchers. |
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356 | |
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357 | =back |
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358 | |
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359 | |
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360 | =head1 WATCHER OBJECTS |
125 | |
361 | |
126 | A watcher is an object that gets created to record your interest in some |
362 | A watcher is an object that gets created to record your interest in some |
127 | event. For instance, if you want to wait for STDIN to become readable, you |
363 | event. For instance, if you want to wait for STDIN to become readable, you |
128 | would create an EV::io watcher for that: |
364 | would create an EV::io watcher for that: |
129 | |
365 | |
130 | my $watcher = EV::io *STDIN, EV::READ, sub { |
366 | my $watcher = EV::io *STDIN, EV::READ, sub { |
131 | my ($watcher, $revents) = @_; |
367 | my ($watcher, $revents) = @_; |
132 | warn "yeah, STDIN should not be readable without blocking!\n" |
368 | warn "yeah, STDIN should now be readable without blocking!\n" |
133 | }; |
369 | }; |
134 | |
370 | |
135 | All watchers can be active (waiting for events) or inactive (paused). Only |
371 | All watchers can be active (waiting for events) or inactive (paused). Only |
136 | active watchers will have their callbacks invoked. All callbacks will be |
372 | active watchers will have their callbacks invoked. All callbacks will be |
137 | called with at least two arguments: the watcher and a bitmask of received |
373 | called with at least two arguments: the watcher and a bitmask of received |
138 | events. |
374 | events. |
139 | |
375 | |
140 | Each watcher type has its associated bit in revents, so you can use the |
376 | Each watcher type has its associated bit in revents, so you can use the |
141 | same callback for multiple watchers. The event mask is named after the |
377 | same callback for multiple watchers. The event mask is named after the |
142 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
378 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
143 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
379 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
144 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
380 | (which can set both EV::READ and EV::WRITE bits). |
145 | uses EV::TIMEOUT). |
|
|
146 | |
381 | |
147 | In the rare case where one wants to create a watcher but not start it at |
382 | In the rare case where one wants to create a watcher but not start it at |
148 | the same time, each constructor has a variant with a trailing C<_ns> in |
383 | the same time, each constructor has a variant with a trailing C<_ns> in |
149 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
384 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
150 | |
385 | |
… | |
… | |
154 | |
389 | |
155 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
390 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
156 | ->fh and so on) automatically stop and start it again if it is active, |
391 | ->fh and so on) automatically stop and start it again if it is active, |
157 | which means pending events get lost. |
392 | which means pending events get lost. |
158 | |
393 | |
159 | =head2 WATCHER TYPES |
394 | =head2 COMMON WATCHER METHODS |
160 | |
395 | |
161 | Now lets move to the existing watcher types and asociated methods. |
396 | This section lists methods common to all watchers. |
162 | |
|
|
163 | The following methods are available for all watchers. Then followes a |
|
|
164 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
|
|
165 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
|
|
166 | any type-specific methods (if any). |
|
|
167 | |
397 | |
168 | =over 4 |
398 | =over 4 |
169 | |
399 | |
170 | =item $w->start |
400 | =item $w->start |
171 | |
401 | |
… | |
… | |
175 | |
405 | |
176 | =item $w->stop |
406 | =item $w->stop |
177 | |
407 | |
178 | Stop a watcher if it is active. Also clear any pending events (events that |
408 | Stop a watcher if it is active. Also clear any pending events (events that |
179 | have been received but that didn't yet result in a callback invocation), |
409 | have been received but that didn't yet result in a callback invocation), |
180 | regardless of wether the watcher was active or not. |
410 | regardless of whether the watcher was active or not. |
181 | |
411 | |
182 | =item $bool = $w->is_active |
412 | =item $bool = $w->is_active |
183 | |
413 | |
184 | Returns true if the watcher is active, false otherwise. |
414 | Returns true if the watcher is active, false otherwise. |
185 | |
415 | |
… | |
… | |
210 | watchers with higher priority will be invoked first. The valid range of |
440 | watchers with higher priority will be invoked first. The valid range of |
211 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
441 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
212 | -2). If the priority is outside this range it will automatically be |
442 | -2). If the priority is outside this range it will automatically be |
213 | normalised to the nearest valid priority. |
443 | normalised to the nearest valid priority. |
214 | |
444 | |
215 | The default priority of any newly-created weatcher is 0. |
445 | The default priority of any newly-created watcher is 0. |
216 | |
446 | |
|
|
447 | Note that the priority semantics have not yet been fleshed out and are |
|
|
448 | subject to almost certain change. |
|
|
449 | |
217 | =item $w->trigger ($revents) |
450 | =item $w->invoke ($revents) |
218 | |
451 | |
219 | Call the callback *now* with the given event mask. |
452 | Call the callback *now* with the given event mask. |
220 | |
453 | |
|
|
454 | =item $w->feed_event ($revents) |
|
|
455 | |
|
|
456 | Feed some events on this watcher into EV. EV will react to this call as if |
|
|
457 | the watcher had received the given C<$revents> mask. |
|
|
458 | |
|
|
459 | =item $revents = $w->clear_pending |
|
|
460 | |
|
|
461 | If the watcher is pending, this function clears its pending status and |
|
|
462 | returns its C<$revents> bitset (as if its callback was invoked). If the |
|
|
463 | watcher isn't pending it does nothing and returns C<0>. |
|
|
464 | |
|
|
465 | =item $previous_state = $w->keepalive ($bool) |
|
|
466 | |
|
|
467 | Normally, C<EV::loop> will return when there are no active watchers |
|
|
468 | (which is a "deadlock" because no progress can be made anymore). This is |
|
|
469 | convenient because it allows you to start your watchers (and your jobs), |
|
|
470 | call C<EV::loop> once and when it returns you know that all your jobs are |
|
|
471 | finished (or they forgot to register some watchers for their task :). |
|
|
472 | |
|
|
473 | Sometimes, however, this gets in your way, for example when the module |
|
|
474 | that calls C<EV::loop> (usually the main program) is not the same module |
|
|
475 | as a long-living watcher (for example a DNS client module written by |
|
|
476 | somebody else even). Then you might want any outstanding requests to be |
|
|
477 | handled, but you would not want to keep C<EV::loop> from returning just |
|
|
478 | because you happen to have this long-running UDP port watcher. |
|
|
479 | |
|
|
480 | In this case you can clear the keepalive status, which means that even |
|
|
481 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
|
482 | |
|
|
483 | The initial value for keepalive is true (enabled), and you can change it |
|
|
484 | any time. |
|
|
485 | |
|
|
486 | Example: Register an I/O watcher for some UDP socket but do not keep the |
|
|
487 | event loop from running just because of that watcher. |
|
|
488 | |
|
|
489 | my $udp_socket = ... |
|
|
490 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
491 | $udp_watcher->keepalive (0); |
|
|
492 | |
|
|
493 | =item $loop = $w->loop |
|
|
494 | |
|
|
495 | Return the loop that this watcher is attached to. |
|
|
496 | |
|
|
497 | =back |
|
|
498 | |
|
|
499 | |
|
|
500 | =head1 WATCHER TYPES |
|
|
501 | |
|
|
502 | Each of the following subsections describes a single watcher type. |
|
|
503 | |
|
|
504 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
|
505 | |
|
|
506 | =over 4 |
221 | |
507 | |
222 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
508 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
223 | |
509 | |
224 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
510 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
225 | |
511 | |
|
|
512 | =item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
513 | |
|
|
514 | =item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
|
|
515 | |
226 | As long as the returned watcher object is alive, call the C<$callback> |
516 | As long as the returned watcher object is alive, call the C<$callback> |
227 | when the events specified in C<$eventmask>. |
517 | when at least one of events specified in C<$eventmask> occurs. |
228 | |
518 | |
229 | The $eventmask can be one or more of these constants ORed together: |
519 | The $eventmask can be one or more of these constants ORed together: |
230 | |
520 | |
231 | EV::READ wait until read() wouldn't block anymore |
521 | EV::READ wait until read() wouldn't block anymore |
232 | EV::WRITE wait until write() wouldn't block anymore |
522 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
248 | |
538 | |
249 | =item $old_eventmask = $w->events ($new_eventmask) |
539 | =item $old_eventmask = $w->events ($new_eventmask) |
250 | |
540 | |
251 | Returns the previously set event mask and optionally set a new one. |
541 | Returns the previously set event mask and optionally set a new one. |
252 | |
542 | |
|
|
543 | =back |
|
|
544 | |
|
|
545 | |
|
|
546 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
|
547 | |
|
|
548 | =over 4 |
253 | |
549 | |
254 | =item $w = EV::timer $after, $repeat, $callback |
550 | =item $w = EV::timer $after, $repeat, $callback |
255 | |
551 | |
256 | =item $w = EV::timer_ns $after, $repeat, $callback |
552 | =item $w = EV::timer_ns $after, $repeat, $callback |
257 | |
553 | |
258 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
554 | =item $w = $loop->timer ($after, $repeat, $callback) |
259 | the timer will be restarted (with the $repeat value as $after) after the |
555 | |
260 | callback returns. |
556 | =item $w = $loop->timer_ns ($after, $repeat, $callback) |
|
|
557 | |
|
|
558 | Calls the callback after C<$after> seconds (which may be fractional). If |
|
|
559 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
|
|
560 | value as $after) after the callback returns. |
261 | |
561 | |
262 | This means that the callback would be called roughly after C<$after> |
562 | This means that the callback would be called roughly after C<$after> |
263 | seconds, and then every C<$repeat> seconds. The timer does his best not |
563 | seconds, and then every C<$repeat> seconds. The timer does his best not |
264 | to drift, but it will not invoke the timer more often then once per event |
564 | to drift, but it will not invoke the timer more often then once per event |
265 | loop iteration, and might drift in other cases. If that isn't acceptable, |
565 | loop iteration, and might drift in other cases. If that isn't acceptable, |
… | |
… | |
271 | |
571 | |
272 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
572 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
273 | |
573 | |
274 | =item $w->set ($after, $repeat) |
574 | =item $w->set ($after, $repeat) |
275 | |
575 | |
276 | Reconfigures the watcher, see the constructor above for details. Can be at |
576 | Reconfigures the watcher, see the constructor above for details. Can be called at |
277 | any time. |
577 | any time. |
278 | |
578 | |
279 | =item $w->again |
579 | =item $w->again |
280 | |
580 | |
281 | Similar to the C<start> method, but has special semantics for repeating timers: |
581 | Similar to the C<start> method, but has special semantics for repeating timers: |
… | |
… | |
292 | This behaviour is useful when you have a timeout for some IO |
592 | This behaviour is useful when you have a timeout for some IO |
293 | operation. You create a timer object with the same value for C<$after> and |
593 | operation. You create a timer object with the same value for C<$after> and |
294 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
594 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
295 | on the timeout. |
595 | on the timeout. |
296 | |
596 | |
|
|
597 | =back |
|
|
598 | |
|
|
599 | |
|
|
600 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
601 | |
|
|
602 | =over 4 |
297 | |
603 | |
298 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
604 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
299 | |
605 | |
300 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
606 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
|
|
607 | |
|
|
608 | =item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
|
|
609 | |
|
|
610 | =item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
301 | |
611 | |
302 | Similar to EV::timer, but is not based on relative timeouts but on |
612 | Similar to EV::timer, but is not based on relative timeouts but on |
303 | absolute times. Apart from creating "simple" timers that trigger "at" the |
613 | absolute times. Apart from creating "simple" timers that trigger "at" the |
304 | specified time, it can also be used for non-drifting absolute timers and |
614 | specified time, it can also be used for non-drifting absolute timers and |
305 | more complex, cron-like, setups that are not adversely affected by time |
615 | more complex, cron-like, setups that are not adversely affected by time |
… | |
… | |
315 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
625 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
316 | will not adjust when a time jump occurs, that is, if it is to be run |
626 | will not adjust when a time jump occurs, that is, if it is to be run |
317 | at January 1st 2011 then it will run when the system time reaches or |
627 | at January 1st 2011 then it will run when the system time reaches or |
318 | surpasses this time. |
628 | surpasses this time. |
319 | |
629 | |
320 | =item * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
630 | =item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
321 | |
631 | |
322 | In this mode the watcher will always be scheduled to time out at the |
632 | In this mode the watcher will always be scheduled to time out at the |
323 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
633 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
324 | regardless of any time jumps. |
634 | regardless of any time jumps. |
325 | |
635 | |
… | |
… | |
343 | time the periodic watcher gets scheduled, the reschedule callback |
653 | time the periodic watcher gets scheduled, the reschedule callback |
344 | ($reschedule_cb) will be called with the watcher as first, and the current |
654 | ($reschedule_cb) will be called with the watcher as first, and the current |
345 | time as second argument. |
655 | time as second argument. |
346 | |
656 | |
347 | I<This callback MUST NOT stop or destroy this or any other periodic |
657 | I<This callback MUST NOT stop or destroy this or any other periodic |
348 | watcher, ever>. If you need to stop it, return 1e30 and stop it |
658 | watcher, ever, and MUST NOT call any event loop functions or methods>. If |
349 | afterwards. |
659 | you need to stop it, return 1e30 and stop it afterwards. You may create |
|
|
660 | and start a C<EV::prepare> watcher for this task. |
350 | |
661 | |
351 | It must return the next time to trigger, based on the passed time value |
662 | It must return the next time to trigger, based on the passed time value |
352 | (that is, the lowest time value larger than to the second argument). It |
663 | (that is, the lowest time value larger than or equal to to the second |
353 | will usually be called just before the callback will be triggered, but |
664 | argument). It will usually be called just before the callback will be |
354 | might be called at other times, too. |
665 | triggered, but might be called at other times, too. |
355 | |
666 | |
356 | This can be used to create very complex timers, such as a timer that |
667 | This can be used to create very complex timers, such as a timer that |
357 | triggers on each midnight, local time (actually 24 hours after the last |
668 | triggers on each midnight, local time (actually 24 hours after the last |
358 | midnight, to keep the example simple. If you know a way to do it correctly |
669 | midnight, to keep the example simple. If you know a way to do it correctly |
359 | in about the same space (without requiring elaborate modules), drop me a |
670 | in about the same space (without requiring elaborate modules), drop me a |
… | |
… | |
373 | |
684 | |
374 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
685 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
375 | |
686 | |
376 | =item $w->set ($at, $interval, $reschedule_cb) |
687 | =item $w->set ($at, $interval, $reschedule_cb) |
377 | |
688 | |
378 | Reconfigures the watcher, see the constructor above for details. Can be at |
689 | Reconfigures the watcher, see the constructor above for details. Can be called at |
379 | any time. |
690 | any time. |
380 | |
691 | |
381 | =item $w->again |
692 | =item $w->again |
382 | |
693 | |
383 | Simply stops and starts the watcher again. |
694 | Simply stops and starts the watcher again. |
384 | |
695 | |
|
|
696 | =item $time = $w->at |
|
|
697 | |
|
|
698 | Return the time that the watcher is expected to trigger next. |
|
|
699 | |
|
|
700 | =back |
|
|
701 | |
|
|
702 | |
|
|
703 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
704 | |
|
|
705 | =over 4 |
385 | |
706 | |
386 | =item $w = EV::signal $signal, $callback |
707 | =item $w = EV::signal $signal, $callback |
387 | |
708 | |
388 | =item $w = EV::signal_ns $signal, $callback |
709 | =item $w = EV::signal_ns $signal, $callback |
389 | |
710 | |
|
|
711 | =item $w = $loop->signal ($signal, $callback) |
|
|
712 | |
|
|
713 | =item $w = $loop->signal_ns ($signal, $callback) |
|
|
714 | |
390 | Call the callback when $signal is received (the signal can be specified |
715 | Call the callback when $signal is received (the signal can be specified by |
391 | by number or by name, just as with kill or %SIG). |
716 | number or by name, just as with C<kill> or C<%SIG>). |
|
|
717 | |
|
|
718 | Only one event loop can grab a given signal - attempting to grab the same |
|
|
719 | signal from two EV loops will crash the program immediately or cause data |
|
|
720 | corruption. |
392 | |
721 | |
393 | EV will grab the signal for the process (the kernel only allows one |
722 | EV will grab the signal for the process (the kernel only allows one |
394 | component to receive a signal at a time) when you start a signal watcher, |
723 | component to receive a signal at a time) when you start a signal watcher, |
395 | and removes it again when you stop it. Perl does the same when you |
724 | and removes it again when you stop it. Perl does the same when you |
396 | add/remove callbacks to %SIG, so watch out. |
725 | add/remove callbacks to C<%SIG>, so watch out. |
397 | |
726 | |
398 | You can have as many signal watchers per signal as you want. |
727 | You can have as many signal watchers per signal as you want. |
399 | |
728 | |
400 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
729 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
401 | |
730 | |
402 | =item $w->set ($signal) |
731 | =item $w->set ($signal) |
403 | |
732 | |
404 | Reconfigures the watcher, see the constructor above for details. Can be at |
733 | Reconfigures the watcher, see the constructor above for details. Can be |
405 | any time. |
734 | called at any time. |
406 | |
735 | |
407 | =item $current_signum = $w->signal |
736 | =item $current_signum = $w->signal |
408 | |
737 | |
409 | =item $old_signum = $w->signal ($new_signal) |
738 | =item $old_signum = $w->signal ($new_signal) |
410 | |
739 | |
411 | Returns the previously set signal (always as a number not name) and |
740 | Returns the previously set signal (always as a number not name) and |
412 | optionally set a new one. |
741 | optionally set a new one. |
413 | |
742 | |
|
|
743 | =back |
414 | |
744 | |
|
|
745 | |
|
|
746 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
747 | |
|
|
748 | =over 4 |
|
|
749 | |
415 | =item $w = EV::child $pid, $callback |
750 | =item $w = EV::child $pid, $trace, $callback |
416 | |
751 | |
417 | =item $w = EV::child_ns $pid, $callback |
752 | =item $w = EV::child_ns $pid, $trace, $callback |
|
|
753 | |
|
|
754 | =item $w = $loop->child ($pid, $trace, $callback) |
|
|
755 | |
|
|
756 | =item $w = $loop->child_ns ($pid, $trace, $callback) |
418 | |
757 | |
419 | Call the callback when a status change for pid C<$pid> (or any pid |
758 | Call the callback when a status change for pid C<$pid> (or any pid |
420 | if C<$pid> is 0) has been received. More precisely: when the process |
759 | if C<$pid> is 0) has been received (a status change happens when the |
|
|
760 | process terminates or is killed, or, when trace is true, additionally when |
|
|
761 | it is stopped or continued). More precisely: when the process receives |
421 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
762 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
422 | changed/zombie children and call the callback. |
763 | changed/zombie children and call the callback. |
423 | |
764 | |
424 | You can access both status and pid by using the C<rstatus> and C<rpid> |
765 | It is valid (and fully supported) to install a child watcher after a child |
425 | methods on the watcher object. |
766 | has exited but before the event loop has started its next iteration (for |
|
|
767 | example, first you C<fork>, then the new child process might exit, and |
|
|
768 | only then do you install a child watcher in the parent for the new pid). |
426 | |
769 | |
|
|
770 | You can access both exit (or tracing) status and pid by using the |
|
|
771 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
772 | |
427 | You can have as many pid watchers per pid as you want. |
773 | You can have as many pid watchers per pid as you want, they will all be |
|
|
774 | called. |
428 | |
775 | |
429 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
776 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
430 | |
777 | |
431 | =item $w->set ($pid) |
778 | =item $w->set ($pid, $trace) |
432 | |
779 | |
433 | Reconfigures the watcher, see the constructor above for details. Can be at |
780 | Reconfigures the watcher, see the constructor above for details. Can be called at |
434 | any time. |
781 | any time. |
435 | |
782 | |
436 | =item $current_pid = $w->pid |
783 | =item $current_pid = $w->pid |
437 | |
|
|
438 | =item $old_pid = $w->pid ($new_pid) |
|
|
439 | |
784 | |
440 | Returns the previously set process id and optionally set a new one. |
785 | Returns the previously set process id and optionally set a new one. |
441 | |
786 | |
442 | =item $exit_status = $w->rstatus |
787 | =item $exit_status = $w->rstatus |
443 | |
788 | |
… | |
… | |
447 | =item $pid = $w->rpid |
792 | =item $pid = $w->rpid |
448 | |
793 | |
449 | Return the pid of the awaited child (useful when you have installed a |
794 | Return the pid of the awaited child (useful when you have installed a |
450 | watcher for all pids). |
795 | watcher for all pids). |
451 | |
796 | |
|
|
797 | =back |
|
|
798 | |
|
|
799 | |
|
|
800 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
801 | |
|
|
802 | =over 4 |
|
|
803 | |
|
|
804 | =item $w = EV::stat $path, $interval, $callback |
|
|
805 | |
|
|
806 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
807 | |
|
|
808 | =item $w = $loop->stat ($path, $interval, $callback) |
|
|
809 | |
|
|
810 | =item $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
811 | |
|
|
812 | Call the callback when a file status change has been detected on |
|
|
813 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
814 | to "path does not exist" is a status change like any other. |
|
|
815 | |
|
|
816 | The C<$interval> is a recommended polling interval for systems where |
|
|
817 | OS-supported change notifications don't exist or are not supported. If |
|
|
818 | you use C<0> then an unspecified default is used (which is highly |
|
|
819 | recommended!), which is to be expected to be around five seconds usually. |
|
|
820 | |
|
|
821 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
822 | as even with OS-supported change notifications, this can be |
|
|
823 | resource-intensive. |
|
|
824 | |
|
|
825 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
826 | |
|
|
827 | =item ... = $w->stat |
|
|
828 | |
|
|
829 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
830 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
831 | well as EV's idea of the current stat values) to the values found. |
|
|
832 | |
|
|
833 | In scalar context, a boolean is return indicating success or failure of |
|
|
834 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
835 | (except that the blksize and blocks fields are not reliable). |
|
|
836 | |
|
|
837 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
838 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
839 | was successful then nlink is guaranteed to be non-zero). |
|
|
840 | |
|
|
841 | See also the next two entries for more info. |
|
|
842 | |
|
|
843 | =item ... = $w->attr |
|
|
844 | |
|
|
845 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
846 | the values most recently detected by EV. See the next entry for more info. |
|
|
847 | |
|
|
848 | =item ... = $w->prev |
|
|
849 | |
|
|
850 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
851 | the previous set of values, before the change. |
|
|
852 | |
|
|
853 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
854 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
855 | returns the values found leading to the change detection. The difference (if any) |
|
|
856 | between C<prev> and C<attr> is what triggered the callback. |
|
|
857 | |
|
|
858 | If you did something to the filesystem object and do not want to trigger |
|
|
859 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
860 | current attributes are. |
|
|
861 | |
|
|
862 | =item $w->set ($path, $interval) |
|
|
863 | |
|
|
864 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
865 | called at any time. |
|
|
866 | |
|
|
867 | =item $current_path = $w->path |
|
|
868 | |
|
|
869 | =item $old_path = $w->path ($new_path) |
|
|
870 | |
|
|
871 | Returns the previously set path and optionally set a new one. |
|
|
872 | |
|
|
873 | =item $current_interval = $w->interval |
|
|
874 | |
|
|
875 | =item $old_interval = $w->interval ($new_interval) |
|
|
876 | |
|
|
877 | Returns the previously set interval and optionally set a new one. Can be |
|
|
878 | used to query the actual interval used. |
|
|
879 | |
|
|
880 | =back |
|
|
881 | |
|
|
882 | |
|
|
883 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
884 | |
|
|
885 | =over 4 |
452 | |
886 | |
453 | =item $w = EV::idle $callback |
887 | =item $w = EV::idle $callback |
454 | |
888 | |
455 | =item $w = EV::idle_ns $callback |
889 | =item $w = EV::idle_ns $callback |
456 | |
890 | |
457 | Call the callback when there are no pending io, timer/periodic, signal or |
891 | =item $w = $loop->idle ($callback) |
458 | child events, i.e. when the process is idle. |
892 | |
|
|
893 | =item $w = $loop->idle_ns ($callback) |
|
|
894 | |
|
|
895 | Call the callback when there are no other pending watchers of the same or |
|
|
896 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
897 | same or lower priority, of course). They are called idle watchers because |
|
|
898 | when the watcher is the highest priority pending event in the process, the |
|
|
899 | process is considered to be idle at that priority. |
|
|
900 | |
|
|
901 | If you want a watcher that is only ever called when I<no> other events are |
|
|
902 | outstanding you have to set the priority to C<EV::MINPRI>. |
459 | |
903 | |
460 | The process will not block as long as any idle watchers are active, and |
904 | The process will not block as long as any idle watchers are active, and |
461 | they will be called repeatedly until stopped. |
905 | they will be called repeatedly until stopped. |
462 | |
906 | |
|
|
907 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
908 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
909 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
910 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
911 | pending with the C<0>-priority idle watcher be invoked. |
|
|
912 | |
463 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
913 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
464 | |
914 | |
|
|
915 | =back |
|
|
916 | |
|
|
917 | |
|
|
918 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
919 | |
|
|
920 | =over 4 |
465 | |
921 | |
466 | =item $w = EV::prepare $callback |
922 | =item $w = EV::prepare $callback |
467 | |
923 | |
468 | =item $w = EV::prepare_ns $callback |
924 | =item $w = EV::prepare_ns $callback |
|
|
925 | |
|
|
926 | =item $w = $loop->prepare ($callback) |
|
|
927 | |
|
|
928 | =item $w = $loop->prepare_ns ($callback) |
469 | |
929 | |
470 | Call the callback just before the process would block. You can still |
930 | Call the callback just before the process would block. You can still |
471 | create/modify any watchers at this point. |
931 | create/modify any watchers at this point. |
472 | |
932 | |
473 | See the EV::check watcher, below, for explanations and an example. |
933 | See the EV::check watcher, below, for explanations and an example. |
474 | |
934 | |
475 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
935 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
476 | |
936 | |
|
|
937 | =back |
|
|
938 | |
|
|
939 | |
|
|
940 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
941 | |
|
|
942 | =over 4 |
477 | |
943 | |
478 | =item $w = EV::check $callback |
944 | =item $w = EV::check $callback |
479 | |
945 | |
480 | =item $w = EV::check_ns $callback |
946 | =item $w = EV::check_ns $callback |
|
|
947 | |
|
|
948 | =item $w = $loop->check ($callback) |
|
|
949 | |
|
|
950 | =item $w = $loop->check_ns ($callback) |
481 | |
951 | |
482 | Call the callback just after the process wakes up again (after it has |
952 | Call the callback just after the process wakes up again (after it has |
483 | gathered events), but before any other callbacks have been invoked. |
953 | gathered events), but before any other callbacks have been invoked. |
484 | |
954 | |
485 | This is used to integrate other event-based software into the EV |
955 | This can be used to integrate other event-based software into the EV |
486 | mainloop: You register a prepare callback and in there, you create io and |
956 | mainloop: You register a prepare callback and in there, you create io and |
487 | timer watchers as required by the other software. Here is a real-world |
957 | timer watchers as required by the other software. Here is a real-world |
488 | example of integrating Net::SNMP (with some details left out): |
958 | example of integrating Net::SNMP (with some details left out): |
489 | |
959 | |
490 | our @snmp_watcher; |
960 | our @snmp_watcher; |
… | |
… | |
493 | # do nothing unless active |
963 | # do nothing unless active |
494 | $dispatcher->{_event_queue_h} |
964 | $dispatcher->{_event_queue_h} |
495 | or return; |
965 | or return; |
496 | |
966 | |
497 | # make the dispatcher handle any outstanding stuff |
967 | # make the dispatcher handle any outstanding stuff |
|
|
968 | ... not shown |
498 | |
969 | |
499 | # create an IO watcher for each and every socket |
970 | # create an I/O watcher for each and every socket |
500 | @snmp_watcher = ( |
971 | @snmp_watcher = ( |
501 | (map { EV::io $_, EV::READ, sub { } } |
972 | (map { EV::io $_, EV::READ, sub { } } |
502 | keys %{ $dispatcher->{_descriptors} }), |
973 | keys %{ $dispatcher->{_descriptors} }), |
|
|
974 | |
|
|
975 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
976 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
977 | 0, sub { }, |
503 | ); |
978 | ); |
504 | |
|
|
505 | # if there are any timeouts, also create a timer |
|
|
506 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
507 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
508 | }; |
979 | }; |
509 | |
980 | |
510 | The callbacks are irrelevant, the only purpose of those watchers is |
981 | The callbacks are irrelevant (and are not even being called), the |
511 | to wake up the process as soon as one of those events occurs (socket |
982 | only purpose of those watchers is to wake up the process as soon as |
512 | readable, or timer timed out). The corresponding EV::check watcher will then |
983 | one of those events occurs (socket readable, or timer timed out). The |
513 | clean up: |
984 | corresponding EV::check watcher will then clean up: |
514 | |
985 | |
515 | our $snmp_check = EV::check sub { |
986 | our $snmp_check = EV::check sub { |
516 | # destroy all watchers |
987 | # destroy all watchers |
517 | @snmp_watcher = (); |
988 | @snmp_watcher = (); |
518 | |
989 | |
519 | # make the dispatcher handle any new stuff |
990 | # make the dispatcher handle any new stuff |
|
|
991 | ... not shown |
520 | }; |
992 | }; |
521 | |
993 | |
522 | The callbacks of the created watchers will not be called as the watchers |
994 | The callbacks of the created watchers will not be called as the watchers |
523 | are destroyed before this cna happen (remember EV::check gets called |
995 | are destroyed before this can happen (remember EV::check gets called |
524 | first). |
996 | first). |
525 | |
997 | |
526 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
998 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
527 | |
999 | |
528 | =back |
1000 | =item EV::CHECK constant issues |
529 | |
1001 | |
|
|
1002 | Like all other watcher types, there is a bitmask constant for use in |
|
|
1003 | C<$revents> and other places. The C<EV::CHECK> is special as it has |
|
|
1004 | the same name as the C<CHECK> sub called by Perl. This doesn't cause |
|
|
1005 | big issues on newer perls (beginning with 5.8.9), but it means thatthe |
|
|
1006 | constant must be I<inlined>, i.e. runtime calls will not work. That means |
|
|
1007 | that as long as you always C<use EV> and then C<EV::CHECK> you are on the |
|
|
1008 | safe side. |
|
|
1009 | |
|
|
1010 | =back |
|
|
1011 | |
|
|
1012 | |
|
|
1013 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
1014 | |
|
|
1015 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
1016 | is done before the event loop blocks next and before C<check> watchers |
|
|
1017 | are being called, and only in the child after the fork. |
|
|
1018 | |
|
|
1019 | =over 4 |
|
|
1020 | |
|
|
1021 | =item $w = EV::fork $callback |
|
|
1022 | |
|
|
1023 | =item $w = EV::fork_ns $callback |
|
|
1024 | |
|
|
1025 | =item $w = $loop->fork ($callback) |
|
|
1026 | |
|
|
1027 | =item $w = $loop->fork_ns ($callback) |
|
|
1028 | |
|
|
1029 | Call the callback before the event loop is resumed in the child process |
|
|
1030 | after a fork. |
|
|
1031 | |
|
|
1032 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
1033 | |
|
|
1034 | =back |
|
|
1035 | |
|
|
1036 | |
|
|
1037 | =head3 EMBED WATCHERS - when one backend isn't enough... |
|
|
1038 | |
|
|
1039 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1040 | into another (currently only IO events are supported in the embedded |
|
|
1041 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
1042 | fashion and must not be used). |
|
|
1043 | |
|
|
1044 | See the libev documentation at |
|
|
1045 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> |
|
|
1046 | (locally installed as F<EV::libev>) for more details. |
|
|
1047 | |
|
|
1048 | In short, this watcher is most useful on BSD systems without working |
|
|
1049 | kqueue to still be able to handle a large number of sockets: |
|
|
1050 | |
|
|
1051 | my $socket_loop; |
|
|
1052 | |
|
|
1053 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
1054 | if ( |
|
|
1055 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
1056 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
1057 | ) { |
|
|
1058 | # use kqueue for sockets |
|
|
1059 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
1060 | } |
|
|
1061 | |
|
|
1062 | # use the default loop otherwise |
|
|
1063 | $socket_loop ||= EV::default_loop; |
|
|
1064 | |
|
|
1065 | =over 4 |
|
|
1066 | |
|
|
1067 | =item $w = EV::embed $otherloop[, $callback] |
|
|
1068 | |
|
|
1069 | =item $w = EV::embed_ns $otherloop[, $callback] |
|
|
1070 | |
|
|
1071 | =item $w = $loop->embed ($otherloop[, $callback]) |
|
|
1072 | |
|
|
1073 | =item $w = $loop->embed_ns ($otherloop[, $callback]) |
|
|
1074 | |
|
|
1075 | Call the callback when the embedded event loop (C<$otherloop>) has any |
|
|
1076 | I/O activity. The C<$callback> is optional: if it is missing, then the |
|
|
1077 | embedded event loop will be managed automatically (which is recommended), |
|
|
1078 | otherwise you have to invoke C<sweep> yourself. |
|
|
1079 | |
|
|
1080 | The C<embed_ns> variant doesn't start (activate) the newly created watcher. |
|
|
1081 | |
|
|
1082 | =back |
|
|
1083 | |
|
|
1084 | =head3 ASYNC WATCHERS - how to wake up another event loop |
|
|
1085 | |
|
|
1086 | Async watchers are provided by EV, but have little use in perl directly, |
|
|
1087 | as perl neither supports threads running in parallel nor direct access to |
|
|
1088 | signal handlers or other contexts where they could be of value. |
|
|
1089 | |
|
|
1090 | It is, however, possible to use them from the XS level. |
|
|
1091 | |
|
|
1092 | Please see the libev documentation for further details. |
|
|
1093 | |
|
|
1094 | =over 4 |
|
|
1095 | |
|
|
1096 | =item $w = EV::async $callback |
|
|
1097 | |
|
|
1098 | =item $w = EV::async_ns $callback |
|
|
1099 | |
|
|
1100 | =item $w->send |
|
|
1101 | |
|
|
1102 | =item $bool = $w->async_pending |
|
|
1103 | |
|
|
1104 | =back |
|
|
1105 | |
|
|
1106 | |
|
|
1107 | =head1 PERL SIGNALS |
|
|
1108 | |
|
|
1109 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
1110 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
1111 | handled when Perl runs, which means your signal handler might be invoked |
|
|
1112 | only the next time an event callback is invoked. |
|
|
1113 | |
|
|
1114 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
1115 | ensure proper operations with regards to other event watchers. |
|
|
1116 | |
|
|
1117 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
1118 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
1119 | watcher: |
|
|
1120 | |
|
|
1121 | my $async_check = EV::check sub { }; |
|
|
1122 | |
|
|
1123 | This ensures that perl gets into control for a short time to handle any |
|
|
1124 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
1125 | |
530 | =head1 THREADS |
1126 | =head1 ITHREADS |
531 | |
1127 | |
532 | Threads are not supported by this in any way. Perl pseudo-threads is evil |
1128 | Ithreads are not supported by this module in any way. Perl pseudo-threads |
533 | stuff and must die. |
1129 | is evil stuff and must die. Real threads as provided by Coro are fully |
|
|
1130 | supported (and enhanced support is available via L<Coro::EV>). |
|
|
1131 | |
|
|
1132 | =head1 FORK |
|
|
1133 | |
|
|
1134 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
1135 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
1136 | not supported and usually destructive). Libev makes it possible to work |
|
|
1137 | around this by having a function that recreates the kernel state after |
|
|
1138 | fork in the child. |
|
|
1139 | |
|
|
1140 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
1141 | functionality to do this automatically for you. This function is quite |
|
|
1142 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
1143 | negligible, because everything the function currently does is set a flag |
|
|
1144 | that is checked only when the event loop gets used the next time, so when |
|
|
1145 | you do fork but not use EV, the overhead is minimal. |
|
|
1146 | |
|
|
1147 | On win32, there is no notion of fork so all this doesn't apply, of course. |
534 | |
1148 | |
535 | =cut |
1149 | =cut |
536 | |
1150 | |
537 | our $DIED = sub { |
1151 | our $DIED = sub { |
538 | warn "EV: error in callback (ignoring): $@"; |
1152 | warn "EV: error in callback (ignoring): $@"; |
539 | }; |
1153 | }; |
540 | |
1154 | |
541 | default_loop |
1155 | default_loop |
542 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_METHODS}?'; |
1156 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
543 | |
1157 | |
544 | 1; |
1158 | 1; |
545 | |
1159 | |
546 | =head1 SEE ALSO |
1160 | =head1 SEE ALSO |
547 | |
1161 | |
548 | L<EV::DNS>. |
1162 | L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
1163 | event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient |
|
|
1164 | coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for |
|
|
1165 | event-loop agnostic and portable event driven programming. |
549 | |
1166 | |
550 | =head1 AUTHOR |
1167 | =head1 AUTHOR |
551 | |
1168 | |
552 | Marc Lehmann <schmorp@schmorp.de> |
1169 | Marc Lehmann <schmorp@schmorp.de> |
553 | http://home.schmorp.de/ |
1170 | http://home.schmorp.de/ |
554 | |
1171 | |
555 | =cut |
1172 | =cut |
556 | |
1173 | |