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3 | EV - perl interface to libev, a high performance full-featured event loop |
3 | EV - perl interface to libev, a high performance full-featured event loop |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use EV; |
7 | use EV; |
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8 | |
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9 | # TIMERS |
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10 | |
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11 | my $w = EV::timer 2, 0, sub { |
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12 | warn "is called after 2s"; |
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13 | }; |
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14 | |
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15 | my $w = EV::timer 2, 2, sub { |
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16 | warn "is called roughly every 2s (repeat = 2)"; |
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17 | }; |
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18 | |
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19 | undef $w; # destroy event watcher again |
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20 | |
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21 | my $w = EV::periodic 0, 60, 0, sub { |
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22 | warn "is called every minute, on the minute, exactly"; |
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23 | }; |
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24 | |
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25 | # IO |
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26 | |
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27 | my $w = EV::io *STDIN, EV::READ, sub { |
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28 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
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29 | warn "stdin is readable, you entered: ", <STDIN>; |
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30 | }; |
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31 | |
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32 | # SIGNALS |
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33 | |
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34 | my $w = EV::signal 'QUIT', sub { |
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35 | warn "sigquit received\n"; |
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36 | }; |
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37 | |
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38 | # CHILD/PID STATUS CHANGES |
8 | |
39 | |
9 | # TIMERS |
40 | my $w = EV::child 666, 0, sub { |
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41 | my ($w, $revents) = @_; |
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42 | my $status = $w->rstatus; |
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43 | }; |
10 | |
44 | |
11 | my $w = EV::timer 2, 0, sub { |
45 | # STAT CHANGES |
12 | warn "is called after 2s"; |
46 | my $w = EV::stat "/etc/passwd", 10, sub { |
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47 | my ($w, $revents) = @_; |
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48 | warn $w->path, " has changed somehow.\n"; |
13 | }; |
49 | }; |
14 | |
50 | |
15 | my $w = EV::timer 2, 1, sub { |
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16 | warn "is called roughly every 2s (repeat = 1)"; |
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17 | }; |
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18 | |
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19 | undef $w; # destroy event watcher again |
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20 | |
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21 | my $w = EV::periodic 0, 60, sub { |
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22 | warn "is called every minute, on the minute, exactly"; |
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23 | }; |
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24 | |
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25 | # IO |
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26 | |
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27 | my $w = EV::io *STDIN, EV::READ, sub { |
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28 | my ($w, $revents) = @_; # all callbacks get the watcher object and event mask |
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29 | warn "stdin is readable, you entered: ", <STDIN>; |
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30 | }; |
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31 | |
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32 | # SIGNALS |
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33 | |
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34 | my $w = EV::signal 'QUIT', sub { |
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35 | warn "sigquit received\n"; |
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36 | }; |
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37 | |
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38 | my $w = EV::signal 3, sub { |
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39 | warn "sigquit received (this is GNU/Linux, right?)\n"; |
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40 | }; |
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41 | |
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42 | # CHILD/PID STATUS CHANGES |
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43 | |
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44 | my $w = EV::child 666, sub { |
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45 | my ($w, $revents, $status) = @_; |
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46 | }; |
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47 | |
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48 | # MAINLOOP |
51 | # MAINLOOP |
49 | EV::loop; # loop until EV::loop_done is called |
52 | EV::loop; # loop until EV::unloop is called or all watchers stop |
50 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
53 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
51 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
54 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
52 | |
55 | |
53 | =head1 DESCRIPTION |
56 | =head1 DESCRIPTION |
54 | |
57 | |
55 | This module provides an interface to libev |
58 | This module provides an interface to libev |
56 | (L<http://software.schmorp.de/pkg/libev.html>). |
59 | (L<http://software.schmorp.de/pkg/libev.html>). While the documentation |
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60 | below is comprehensive, one might also consult the documentation of libev |
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61 | itself (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>) for more |
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62 | subtle details on watcher semantics or some discussion on the available |
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63 | backends, or how to force a specific backend with C<LIBEV_FLAGS>, or just |
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64 | about in any case because it has much more detailed information. |
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65 | |
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66 | This module is very fast and scalable. It is actually so fast that you |
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67 | can use it through the L<AnyEvent> module, stay portable to other event |
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68 | loops (if you don't rely on any watcher types not available through it) |
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69 | and still be faster than with any other event loop currently supported in |
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70 | Perl. |
57 | |
71 | |
58 | =cut |
72 | =cut |
59 | |
73 | |
60 | package EV; |
74 | package EV; |
61 | |
75 | |
62 | use strict; |
76 | use strict; |
63 | |
77 | |
64 | BEGIN { |
78 | BEGIN { |
65 | our $VERSION = '0.1'; |
79 | our $VERSION = '3.42'; |
66 | use XSLoader; |
80 | use XSLoader; |
67 | XSLoader::load "EV", $VERSION; |
81 | XSLoader::load "EV", $VERSION; |
68 | } |
82 | } |
69 | |
83 | |
70 | @EV::Io::ISA = |
84 | @EV::IO::ISA = |
71 | @EV::Timer::ISA = |
85 | @EV::Timer::ISA = |
72 | @EV::Periodic::ISA = |
86 | @EV::Periodic::ISA = |
73 | @EV::Signal::ISA = |
87 | @EV::Signal::ISA = |
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88 | @EV::Child::ISA = |
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89 | @EV::Stat::ISA = |
74 | @EV::Idle::ISA = |
90 | @EV::Idle::ISA = |
75 | @EV::Prepare::ISA = |
91 | @EV::Prepare::ISA = |
76 | @EV::Check::ISA = |
92 | @EV::Check::ISA = |
77 | @EV::Child::ISA = "EV::Watcher"; |
93 | @EV::Embed::ISA = |
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94 | @EV::Fork::ISA = |
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95 | @EV::Async::ISA = |
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96 | "EV::Watcher"; |
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97 | |
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98 | @EV::Loop::Default::ISA = "EV::Loop"; |
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99 | |
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100 | =head1 EVENT LOOPS |
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101 | |
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102 | EV supports multiple event loops: There is a single "default event loop" |
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103 | that can handle everything including signals and child watchers, and any |
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104 | number of "dynamic event loops" that can use different backends (with |
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105 | various limitations), but no child and signal watchers. |
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106 | |
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107 | You do not have to do anything to create the default event loop: When |
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108 | the module is loaded a suitable backend is selected on the premise of |
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109 | selecting a working backend (which for example rules out kqueue on most |
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110 | BSDs). Modules should, unless they have "special needs" always use the |
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111 | default loop as this is fastest (perl-wise), best supported by other |
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112 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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113 | |
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114 | For specific programs you can create additional event loops dynamically. |
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115 | |
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116 | If you want to take avdantage of kqueue (which often works properly for |
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117 | sockets only) even though the default loop doesn't enable it, you can |
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118 | I<embed> a kqueue loop into the default loop: running the default loop |
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119 | will then also service the kqueue loop to some extent. See the example in |
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120 | the section about embed watchers for an example on how to achieve that. |
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121 | |
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122 | =over 4 |
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123 | |
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124 | =item $loop = new EV::loop [$flags] |
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125 | |
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126 | Create a new event loop as per the specified flags. Please refer to the |
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127 | C<ev_loop_new ()> function description in the libev documentation |
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128 | (L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTIONS>) |
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129 | for more info. |
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130 | |
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131 | The loop will automatically be destroyed when it is no longer referenced |
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132 | by any watcher and the loop object goes out of scope. |
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133 | |
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134 | Using C<EV::FLAG_FORKCHECK> is recommended, as only the default event loop |
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135 | is protected by this module. |
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136 | |
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137 | =item $loop->loop_fork |
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138 | |
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139 | Must be called after a fork in the child, before entering or continuing |
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140 | the event loop. An alternative is to use C<EV::FLAG_FORKCHECK> which calls |
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141 | this function automatically, at some performance loss (refer to the libev |
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142 | documentation). |
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143 | |
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144 | =item $loop->loop_verify |
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145 | |
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146 | Calls C<ev_verify> to make internal consistency checks (for debugging |
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147 | libev) and abort the program if any data structures were found to be |
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148 | corrupted. |
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149 | |
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150 | =item $loop = EV::default_loop [$flags] |
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151 | |
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152 | Return the default loop (which is a singleton object). Since this module |
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153 | already creates the default loop with default flags, specifying flags here |
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154 | will not have any effect unless you destroy the default loop first, which |
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155 | isn't supported. So in short: don't do it, and if you break it, you get to |
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156 | keep the pieces. |
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157 | |
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158 | =back |
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159 | |
78 | |
160 | |
79 | =head1 BASIC INTERFACE |
161 | =head1 BASIC INTERFACE |
80 | |
162 | |
81 | =over 4 |
163 | =over 4 |
82 | |
164 | |
83 | =item $EV::DIED |
165 | =item $EV::DIED |
84 | |
166 | |
85 | Must contain a reference to a function that is called when a callback |
167 | Must contain a reference to a function that is called when a callback |
86 | throws an exception (with $@ containing thr error). The default prints an |
168 | throws an exception (with $@ containing the error). The default prints an |
87 | informative message and continues. |
169 | informative message and continues. |
88 | |
170 | |
89 | If this callback throws an exception it will be silently ignored. |
171 | If this callback throws an exception it will be silently ignored. |
90 | |
172 | |
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173 | =item $flags = EV::supported_backends |
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174 | |
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175 | =item $flags = EV::recommended_backends |
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176 | |
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177 | =item $flags = EV::embeddable_backends |
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178 | |
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179 | Returns the set (see C<EV::BACKEND_*> flags) of backends supported by this |
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180 | instance of EV, the set of recommended backends (supposed to be good) for |
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181 | this platform and the set of embeddable backends (see EMBED WATCHERS). |
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182 | |
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183 | =item EV::sleep $seconds |
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184 | |
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185 | Block the process for the given number of (fractional) seconds. |
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186 | |
91 | =item $time = EV::time |
187 | =item $time = EV::time |
92 | |
188 | |
93 | Returns the current time in (fractional) seconds since the epoch. |
189 | Returns the current time in (fractional) seconds since the epoch. |
94 | |
190 | |
95 | =item $time = EV::now |
191 | =item $time = EV::now |
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192 | |
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193 | =item $time = $loop->now |
96 | |
194 | |
97 | Returns the time the last event loop iteration has been started. This |
195 | Returns the time the last event loop iteration has been started. This |
98 | is the time that (relative) timers are based on, and refering to it is |
196 | is the time that (relative) timers are based on, and refering to it is |
99 | usually faster then calling EV::time. |
197 | usually faster then calling EV::time. |
100 | |
198 | |
101 | =item $method = EV::ev_method |
199 | =item $backend = EV::backend |
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200 | |
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201 | =item $backend = $loop->backend |
102 | |
202 | |
103 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
203 | Returns an integer describing the backend used by libev (EV::METHOD_SELECT |
104 | or EV::METHOD_EPOLL). |
204 | or EV::METHOD_EPOLL). |
105 | |
205 | |
106 | =item EV::loop [$flags] |
206 | =item EV::loop [$flags] |
107 | |
207 | |
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208 | =item $loop->loop ([$flags]) |
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209 | |
108 | Begin checking for events and calling callbacks. It returns when a |
210 | Begin checking for events and calling callbacks. It returns when a |
109 | callback calls EV::loop_done. |
211 | callback calls EV::unloop. |
110 | |
212 | |
111 | The $flags argument can be one of the following: |
213 | The $flags argument can be one of the following: |
112 | |
214 | |
113 | 0 as above |
215 | 0 as above |
114 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
216 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
115 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
217 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
116 | |
218 | |
117 | =item EV::loop_done [$how] |
219 | =item EV::unloop [$how] |
118 | |
220 | |
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221 | =item $loop->unloop ([$how]) |
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222 | |
119 | When called with no arguments or an argument of 1, makes the innermost |
223 | When called with no arguments or an argument of EV::UNLOOP_ONE, makes the |
120 | call to EV::loop return. |
224 | innermost call to EV::loop return. |
121 | |
225 | |
122 | When called with an agrument of 2, all calls to EV::loop will return as |
226 | When called with an argument of EV::UNLOOP_ALL, all calls to EV::loop will return as |
123 | fast as possible. |
227 | fast as possible. |
124 | |
228 | |
125 | =back |
229 | =item $count = EV::loop_count |
126 | |
230 | |
127 | =head2 WATCHER |
231 | =item $count = $loop->loop_count |
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232 | |
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233 | Return the number of times the event loop has polled for new |
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234 | events. Sometiems useful as a generation counter. |
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235 | |
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236 | =item EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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237 | |
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238 | =item $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
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239 | |
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240 | This function rolls together an I/O and a timer watcher for a single |
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241 | one-shot event without the need for managing a watcher object. |
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242 | |
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243 | If C<$fh_or_undef> is a filehandle or file descriptor, then C<$events> |
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244 | must be a bitset containing either C<EV::READ>, C<EV::WRITE> or C<EV::READ |
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245 | | EV::WRITE>, indicating the type of I/O event you want to wait for. If |
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246 | you do not want to wait for some I/O event, specify C<undef> for |
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247 | C<$fh_or_undef> and C<0> for C<$events>). |
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248 | |
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249 | If timeout is C<undef> or negative, then there will be no |
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250 | timeout. Otherwise a EV::timer with this value will be started. |
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251 | |
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252 | When an error occurs or either the timeout or I/O watcher triggers, then |
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253 | the callback will be called with the received event set (in general |
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254 | you can expect it to be a combination of C<EV::ERROR>, C<EV::READ>, |
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255 | C<EV::WRITE> and C<EV::TIMEOUT>). |
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256 | |
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257 | EV::once doesn't return anything: the watchers stay active till either |
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258 | of them triggers, then they will be stopped and freed, and the callback |
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259 | invoked. |
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260 | |
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261 | =item EV::feed_fd_event ($fd, $revents) |
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262 | |
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263 | =item $loop->feed_fd_event ($fd, $revents) |
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264 | |
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265 | Feed an event on a file descriptor into EV. EV will react to this call as |
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266 | if the readyness notifications specified by C<$revents> (a combination of |
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267 | C<EV::READ> and C<EV::WRITE>) happened on the file descriptor C<$fd>. |
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268 | |
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269 | =item EV::feed_signal_event ($signal) |
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270 | |
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271 | Feed a signal event into EV. EV will react to this call as if the signal |
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272 | specified by C<$signal> had occured. |
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273 | |
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274 | =item EV::set_io_collect_interval $time |
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275 | |
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276 | =item $loop->set_io_collect_interval ($time) |
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277 | |
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278 | =item EV::set_timeout_collect_interval $time |
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279 | |
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280 | =item $loop->set_timeout_collect_interval ($time) |
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281 | |
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282 | These advanced functions set the minimum block interval when polling for I/O events and the minimum |
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283 | wait interval for timer events. See the libev documentation at |
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284 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONTROLLING_THE_EVENT_LOOP> for |
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285 | a more detailed discussion. |
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286 | |
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287 | =back |
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288 | |
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289 | |
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290 | =head1 WATCHER OBJECTS |
128 | |
291 | |
129 | A watcher is an object that gets created to record your interest in some |
292 | A watcher is an object that gets created to record your interest in some |
130 | event. For instance, if you want to wait for STDIN to become readable, you |
293 | event. For instance, if you want to wait for STDIN to become readable, you |
131 | would create an EV::io watcher for that: |
294 | would create an EV::io watcher for that: |
132 | |
295 | |
133 | my $watcher = EV::io *STDIN, EV::READ, sub { |
296 | my $watcher = EV::io *STDIN, EV::READ, sub { |
134 | my ($watcher, $revents) = @_; |
297 | my ($watcher, $revents) = @_; |
135 | warn "yeah, STDIN should not be readable without blocking!\n" |
298 | warn "yeah, STDIN should now be readable without blocking!\n" |
136 | }; |
299 | }; |
137 | |
300 | |
138 | All watchers can be active (waiting for events) or inactive (paused). Only |
301 | All watchers can be active (waiting for events) or inactive (paused). Only |
139 | active watchers will have their callbacks invoked. All callbacks will be |
302 | active watchers will have their callbacks invoked. All callbacks will be |
140 | called with at least two arguments: the watcher and a bitmask of received |
303 | called with at least two arguments: the watcher and a bitmask of received |
141 | events. |
304 | events. |
142 | |
305 | |
143 | Each watcher type has its associated bit in revents, so you can use the |
306 | Each watcher type has its associated bit in revents, so you can use the |
144 | same callback for multiple watchers. The event mask is named after the |
307 | same callback for multiple watchers. The event mask is named after the |
145 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
308 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
146 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO events |
309 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O events |
147 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
310 | (which can set both EV::READ and EV::WRITE bits), and EV::timer (which |
148 | uses EV::TIMEOUT). |
311 | uses EV::TIMEOUT). |
149 | |
312 | |
150 | In the rare case where one wants to create a watcher but not start it at |
313 | In the rare case where one wants to create a watcher but not start it at |
151 | the same time, each constructor has a variant with a trailing C<_ns> in |
314 | the same time, each constructor has a variant with a trailing C<_ns> in |
152 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
315 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
153 | |
316 | |
154 | Please note that a watcher will automatically be stopped when the watcher |
317 | Please note that a watcher will automatically be stopped when the watcher |
155 | object is returned, so you I<need> to keep the watcher objects returned by |
318 | object is destroyed, so you I<need> to keep the watcher objects returned by |
156 | the constructors. |
319 | the constructors. |
157 | |
320 | |
158 | =head2 WATCHER TYPES |
321 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
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322 | ->fh and so on) automatically stop and start it again if it is active, |
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323 | which means pending events get lost. |
159 | |
324 | |
160 | Now lets move to the existing watcher types and asociated methods. |
325 | =head2 COMMON WATCHER METHODS |
161 | |
326 | |
162 | The following methods are available for all watchers. Then followes a |
327 | This section lists methods common to all watchers. |
163 | description of each watcher constructor (EV::io, EV::timer, EV::periodic, |
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164 | EV::signal, EV::child, EV::idle, EV::prepare and EV::check), followed by |
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165 | any type-specific methods (if any). |
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166 | |
328 | |
167 | =over 4 |
329 | =over 4 |
168 | |
330 | |
169 | =item $w->start |
331 | =item $w->start |
170 | |
332 | |
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… | |
174 | |
336 | |
175 | =item $w->stop |
337 | =item $w->stop |
176 | |
338 | |
177 | Stop a watcher if it is active. Also clear any pending events (events that |
339 | Stop a watcher if it is active. Also clear any pending events (events that |
178 | have been received but that didn't yet result in a callback invocation), |
340 | have been received but that didn't yet result in a callback invocation), |
179 | regardless of wether the watcher was active or not. |
341 | regardless of whether the watcher was active or not. |
180 | |
342 | |
181 | =item $bool = $w->is_active |
343 | =item $bool = $w->is_active |
182 | |
344 | |
183 | Returns true if the watcher is active, false otherwise. |
345 | Returns true if the watcher is active, false otherwise. |
184 | |
346 | |
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347 | =item $current_data = $w->data |
|
|
348 | |
|
|
349 | =item $old_data = $w->data ($new_data) |
|
|
350 | |
|
|
351 | Queries a freely usable data scalar on the watcher and optionally changes |
|
|
352 | it. This is a way to associate custom data with a watcher: |
|
|
353 | |
|
|
354 | my $w = EV::timer 60, 0, sub { |
|
|
355 | warn $_[0]->data; |
|
|
356 | }; |
|
|
357 | $w->data ("print me!"); |
|
|
358 | |
185 | =item $current_cb = $w->cb |
359 | =item $current_cb = $w->cb |
186 | |
360 | |
187 | =item $old_cb = $w->cb ($new_cb) |
361 | =item $old_cb = $w->cb ($new_cb) |
188 | |
362 | |
189 | Queries the callback on the watcher and optionally changes it. You cna do |
363 | Queries the callback on the watcher and optionally changes it. You can do |
190 | this at any time. |
364 | this at any time without the watcher restarting. |
191 | |
365 | |
|
|
366 | =item $current_priority = $w->priority |
|
|
367 | |
|
|
368 | =item $old_priority = $w->priority ($new_priority) |
|
|
369 | |
|
|
370 | Queries the priority on the watcher and optionally changes it. Pending |
|
|
371 | watchers with higher priority will be invoked first. The valid range of |
|
|
372 | priorities lies between EV::MAXPRI (default 2) and EV::MINPRI (default |
|
|
373 | -2). If the priority is outside this range it will automatically be |
|
|
374 | normalised to the nearest valid priority. |
|
|
375 | |
|
|
376 | The default priority of any newly-created watcher is 0. |
|
|
377 | |
|
|
378 | Note that the priority semantics have not yet been fleshed out and are |
|
|
379 | subject to almost certain change. |
|
|
380 | |
192 | =item $w->trigger ($revents) |
381 | =item $w->invoke ($revents) |
193 | |
382 | |
194 | Call the callback *now* with the given event mask. |
383 | Call the callback *now* with the given event mask. |
195 | |
384 | |
|
|
385 | =item $w->feed_event ($revents) |
|
|
386 | |
|
|
387 | Feed some events on this watcher into EV. EV will react to this call as if |
|
|
388 | the watcher had received the given C<$revents> mask. |
|
|
389 | |
|
|
390 | =item $revents = $w->clear_pending |
|
|
391 | |
|
|
392 | If the watcher is pending, this function clears its pending status and |
|
|
393 | returns its C<$revents> bitset (as if its callback was invoked). If the |
|
|
394 | watcher isn't pending it does nothing and returns C<0>. |
|
|
395 | |
|
|
396 | =item $previous_state = $w->keepalive ($bool) |
|
|
397 | |
|
|
398 | Normally, C<EV::loop> will return when there are no active watchers |
|
|
399 | (which is a "deadlock" because no progress can be made anymore). This is |
|
|
400 | convinient because it allows you to start your watchers (and your jobs), |
|
|
401 | call C<EV::loop> once and when it returns you know that all your jobs are |
|
|
402 | finished (or they forgot to register some watchers for their task :). |
|
|
403 | |
|
|
404 | Sometimes, however, this gets in your way, for example when the module |
|
|
405 | that calls C<EV::loop> (usually the main program) is not the same module |
|
|
406 | as a long-living watcher (for example a DNS client module written by |
|
|
407 | somebody else even). Then you might want any outstanding requests to be |
|
|
408 | handled, but you would not want to keep C<EV::loop> from returning just |
|
|
409 | because you happen to have this long-running UDP port watcher. |
|
|
410 | |
|
|
411 | In this case you can clear the keepalive status, which means that even |
|
|
412 | though your watcher is active, it won't keep C<EV::loop> from returning. |
|
|
413 | |
|
|
414 | The initial value for keepalive is true (enabled), and you cna change it |
|
|
415 | any time. |
|
|
416 | |
|
|
417 | Example: Register an I/O watcher for some UDP socket but do not keep the |
|
|
418 | event loop from running just because of that watcher. |
|
|
419 | |
|
|
420 | my $udp_socket = ... |
|
|
421 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
422 | $udp_watcher->keepalive (0); |
|
|
423 | |
|
|
424 | =item $loop = $w->loop |
|
|
425 | |
|
|
426 | Return the loop that this watcher is attached to. |
|
|
427 | |
|
|
428 | =back |
|
|
429 | |
|
|
430 | |
|
|
431 | =head1 WATCHER TYPES |
|
|
432 | |
|
|
433 | Each of the following subsections describes a single watcher type. |
|
|
434 | |
|
|
435 | =head3 I/O WATCHERS - is this file descriptor readable or writable? |
|
|
436 | |
|
|
437 | =over 4 |
196 | |
438 | |
197 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
439 | =item $w = EV::io $fileno_or_fh, $eventmask, $callback |
198 | |
440 | |
199 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
441 | =item $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
200 | |
442 | |
|
|
443 | =item $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
444 | |
|
|
445 | =item $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
|
|
446 | |
201 | As long as the returned watcher object is alive, call the C<$callback> |
447 | As long as the returned watcher object is alive, call the C<$callback> |
202 | when the events specified in C<$eventmask>. |
448 | when at least one of events specified in C<$eventmask> occurs. |
203 | |
449 | |
204 | The $eventmask can be one or more of these constants ORed together: |
450 | The $eventmask can be one or more of these constants ORed together: |
205 | |
451 | |
206 | EV::READ wait until read() wouldn't block anymore |
452 | EV::READ wait until read() wouldn't block anymore |
207 | EV::WRITE wait until write() wouldn't block anymore |
453 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
223 | |
469 | |
224 | =item $old_eventmask = $w->events ($new_eventmask) |
470 | =item $old_eventmask = $w->events ($new_eventmask) |
225 | |
471 | |
226 | Returns the previously set event mask and optionally set a new one. |
472 | Returns the previously set event mask and optionally set a new one. |
227 | |
473 | |
|
|
474 | =back |
|
|
475 | |
|
|
476 | |
|
|
477 | =head3 TIMER WATCHERS - relative and optionally repeating timeouts |
|
|
478 | |
|
|
479 | =over 4 |
228 | |
480 | |
229 | =item $w = EV::timer $after, $repeat, $callback |
481 | =item $w = EV::timer $after, $repeat, $callback |
230 | |
482 | |
231 | =item $w = EV::timer_ns $after, $repeat, $callback |
483 | =item $w = EV::timer_ns $after, $repeat, $callback |
232 | |
484 | |
233 | Calls the callback after C<$after> seconds. If C<$repeat> is non-zero, |
485 | =item $w = $loop->timer ($after, $repeat, $callback) |
234 | the timer will be restarted (with the $repeat value as $after) after the |
486 | |
235 | callback returns. |
487 | =item $w = $loop->timer_ns ($after, $repeat, $callback) |
|
|
488 | |
|
|
489 | Calls the callback after C<$after> seconds (which may be fractional). If |
|
|
490 | C<$repeat> is non-zero, the timer will be restarted (with the $repeat |
|
|
491 | value as $after) after the callback returns. |
236 | |
492 | |
237 | This means that the callback would be called roughly after C<$after> |
493 | This means that the callback would be called roughly after C<$after> |
238 | seconds, and then every C<$repeat> seconds. "Roughly" because the time of |
494 | seconds, and then every C<$repeat> seconds. The timer does his best not |
239 | callback processing is not taken into account, so the timer will slowly |
495 | to drift, but it will not invoke the timer more often then once per event |
240 | drift. If that isn't acceptable, look at EV::periodic. |
496 | loop iteration, and might drift in other cases. If that isn't acceptable, |
|
|
497 | look at EV::periodic, which can provide long-term stable timers. |
241 | |
498 | |
242 | The timer is based on a monotonic clock, that is if somebody is sitting |
499 | The timer is based on a monotonic clock, that is, if somebody is sitting |
243 | in front of the machine while the timer is running and changes the system |
500 | in front of the machine while the timer is running and changes the system |
244 | clock, the timer will nevertheless run (roughly) the same time. |
501 | clock, the timer will nevertheless run (roughly) the same time. |
245 | |
502 | |
246 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
503 | The C<timer_ns> variant doesn't start (activate) the newly created watcher. |
247 | |
504 | |
248 | =item $w->set ($after, $repeat) |
505 | =item $w->set ($after, $repeat) |
249 | |
506 | |
250 | Reconfigures the watcher, see the constructor above for details. Can be at |
507 | Reconfigures the watcher, see the constructor above for details. Can be called at |
251 | any time. |
508 | any time. |
252 | |
509 | |
253 | =item $w->again |
510 | =item $w->again |
254 | |
511 | |
255 | Similar to the C<start> method, but has special semantics for repeating timers: |
512 | Similar to the C<start> method, but has special semantics for repeating timers: |
|
|
513 | |
|
|
514 | If the timer is active and non-repeating, it will be stopped. |
256 | |
515 | |
257 | If the timer is active and repeating, reset the timeout to occur |
516 | If the timer is active and repeating, reset the timeout to occur |
258 | C<$repeat> seconds after now. |
517 | C<$repeat> seconds after now. |
259 | |
518 | |
260 | If the timer is active and non-repeating, it will be stopped. |
|
|
261 | |
|
|
262 | If the timer is in active and repeating, start it. |
519 | If the timer is inactive and repeating, start it using the repeat value. |
263 | |
520 | |
264 | Otherwise do nothing. |
521 | Otherwise do nothing. |
265 | |
522 | |
266 | This behaviour is useful when you have a timeout for some IO |
523 | This behaviour is useful when you have a timeout for some IO |
267 | operation. You create a timer object with the same value for C<$after> and |
524 | operation. You create a timer object with the same value for C<$after> and |
268 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
525 | C<$repeat>, and then, in the read/write watcher, run the C<again> method |
269 | on the timeout. |
526 | on the timeout. |
270 | |
527 | |
|
|
528 | =back |
271 | |
529 | |
|
|
530 | |
|
|
531 | =head3 PERIODIC WATCHERS - to cron or not to cron? |
|
|
532 | |
|
|
533 | =over 4 |
|
|
534 | |
272 | =item $w = EV::periodic $at, $interval, $callback |
535 | =item $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
273 | |
536 | |
274 | =item $w = EV::periodic_ns $at, $interval, $callback |
537 | =item $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
275 | |
538 | |
276 | Similar to EV::timer, but the time is given as an absolute point in time |
539 | =item $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
277 | (C<$at>), plus an optional C<$interval>. |
|
|
278 | |
540 | |
279 | If the C<$interval> is zero, then the callback will be called at the time |
541 | =item $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
280 | C<$at> if that is in the future, or as soon as possible if it is in the |
|
|
281 | past. It will not automatically repeat. |
|
|
282 | |
542 | |
283 | If the C<$interval> is nonzero, then the watcher will always be scheduled |
543 | Similar to EV::timer, but is not based on relative timeouts but on |
284 | to time out at the next C<$at + N * $interval> time. |
544 | absolute times. Apart from creating "simple" timers that trigger "at" the |
|
|
545 | specified time, it can also be used for non-drifting absolute timers and |
|
|
546 | more complex, cron-like, setups that are not adversely affected by time |
|
|
547 | jumps (i.e. when the system clock is changed by explicit date -s or other |
|
|
548 | means such as ntpd). It is also the most complex watcher type in EV. |
285 | |
549 | |
286 | This can be used to schedule a callback to run at very regular intervals, |
550 | It has three distinct "modes": |
287 | as long as the processing time is less then the interval (otherwise |
551 | |
288 | obviously events will be skipped). |
552 | =over 4 |
|
|
553 | |
|
|
554 | =item * absolute timer ($interval = $reschedule_cb = 0) |
|
|
555 | |
|
|
556 | This time simply fires at the wallclock time C<$at> and doesn't repeat. It |
|
|
557 | will not adjust when a time jump occurs, that is, if it is to be run |
|
|
558 | at January 1st 2011 then it will run when the system time reaches or |
|
|
559 | surpasses this time. |
|
|
560 | |
|
|
561 | =item * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
562 | |
|
|
563 | In this mode the watcher will always be scheduled to time out at the |
|
|
564 | next C<$at + N * $interval> time (for some integer N) and then repeat, |
|
|
565 | regardless of any time jumps. |
|
|
566 | |
|
|
567 | This can be used to create timers that do not drift with respect to system |
|
|
568 | time: |
|
|
569 | |
|
|
570 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
|
571 | |
|
|
572 | That doesn't mean there will always be 3600 seconds in between triggers, |
|
|
573 | but only that the the clalback will be called when the system time shows a |
|
|
574 | full hour (UTC). |
289 | |
575 | |
290 | Another way to think about it (for the mathematically inclined) is that |
576 | Another way to think about it (for the mathematically inclined) is that |
291 | EV::periodic will try to run the callback at the next possible time where |
577 | EV::periodic will try to run the callback in this mode at the next |
292 | C<$time = $at (mod $interval)>, regardless of any time jumps. |
578 | possible time where C<$time = $at (mod $interval)>, regardless of any time |
|
|
579 | jumps. |
293 | |
580 | |
294 | This periodic timer is based on "wallclock time", that is, if the clock |
581 | =item * manual reschedule mode ($reschedule_cb = coderef) |
295 | changes (C<ntp>, C<date -s> etc.), then the timer will nevertheless run at |
582 | |
296 | the specified time. This means it will never drift (it might jitter, but |
583 | In this mode $interval and $at are both being ignored. Instead, each |
297 | it will not drift). |
584 | time the periodic watcher gets scheduled, the reschedule callback |
|
|
585 | ($reschedule_cb) will be called with the watcher as first, and the current |
|
|
586 | time as second argument. |
|
|
587 | |
|
|
588 | I<This callback MUST NOT stop or destroy this or any other periodic |
|
|
589 | watcher, ever, and MUST NOT call any event loop functions or methods>. If |
|
|
590 | you need to stop it, return 1e30 and stop it afterwards. You may create |
|
|
591 | and start a C<EV::prepare> watcher for this task. |
|
|
592 | |
|
|
593 | It must return the next time to trigger, based on the passed time value |
|
|
594 | (that is, the lowest time value larger than or equal to to the second |
|
|
595 | argument). It will usually be called just before the callback will be |
|
|
596 | triggered, but might be called at other times, too. |
|
|
597 | |
|
|
598 | This can be used to create very complex timers, such as a timer that |
|
|
599 | triggers on each midnight, local time (actually 24 hours after the last |
|
|
600 | midnight, to keep the example simple. If you know a way to do it correctly |
|
|
601 | in about the same space (without requiring elaborate modules), drop me a |
|
|
602 | note :): |
|
|
603 | |
|
|
604 | my $daily = EV::periodic 0, 0, sub { |
|
|
605 | my ($w, $now) = @_; |
|
|
606 | |
|
|
607 | use Time::Local (); |
|
|
608 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
|
609 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
|
610 | }, sub { |
|
|
611 | print "it's midnight or likely shortly after, now\n"; |
|
|
612 | }; |
|
|
613 | |
|
|
614 | =back |
298 | |
615 | |
299 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
616 | The C<periodic_ns> variant doesn't start (activate) the newly created watcher. |
300 | |
617 | |
301 | =item $w->set ($at, $interval) |
618 | =item $w->set ($at, $interval, $reschedule_cb) |
302 | |
619 | |
303 | Reconfigures the watcher, see the constructor above for details. Can be at |
620 | Reconfigures the watcher, see the constructor above for details. Can be called at |
304 | any time. |
621 | any time. |
305 | |
622 | |
|
|
623 | =item $w->again |
|
|
624 | |
|
|
625 | Simply stops and starts the watcher again. |
|
|
626 | |
|
|
627 | =item $time = $w->at |
|
|
628 | |
|
|
629 | Return the time that the watcher is expected to trigger next. |
|
|
630 | |
|
|
631 | =back |
|
|
632 | |
|
|
633 | |
|
|
634 | =head3 SIGNAL WATCHERS - signal me when a signal gets signalled! |
|
|
635 | |
|
|
636 | =over 4 |
306 | |
637 | |
307 | =item $w = EV::signal $signal, $callback |
638 | =item $w = EV::signal $signal, $callback |
308 | |
639 | |
309 | =item $w = EV::signal_ns $signal, $callback |
640 | =item $w = EV::signal_ns $signal, $callback |
310 | |
641 | |
311 | Call the callback when $signal is received (the signal can be specified |
642 | Call the callback when $signal is received (the signal can be specified by |
312 | by number or by name, just as with kill or %SIG). |
643 | number or by name, just as with C<kill> or C<%SIG>). |
313 | |
644 | |
314 | EV will grab the signal for the process (the kernel only allows one |
645 | EV will grab the signal for the process (the kernel only allows one |
315 | component to receive a signal at a time) when you start a signal watcher, |
646 | component to receive a signal at a time) when you start a signal watcher, |
316 | and removes it again when you stop it. Perl does the same when you |
647 | and removes it again when you stop it. Perl does the same when you |
317 | add/remove callbacks to %SIG, so watch out. |
648 | add/remove callbacks to C<%SIG>, so watch out. |
318 | |
649 | |
319 | You can have as many signal watchers per signal as you want. |
650 | You can have as many signal watchers per signal as you want. |
320 | |
651 | |
321 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
652 | The C<signal_ns> variant doesn't start (activate) the newly created watcher. |
322 | |
653 | |
323 | =item $w->set ($signal) |
654 | =item $w->set ($signal) |
324 | |
655 | |
325 | Reconfigures the watcher, see the constructor above for details. Can be at |
656 | Reconfigures the watcher, see the constructor above for details. Can be |
326 | any time. |
657 | called at any time. |
327 | |
658 | |
328 | =item $current_signum = $w->signal |
659 | =item $current_signum = $w->signal |
329 | |
660 | |
330 | =item $old_signum = $w->signal ($new_signal) |
661 | =item $old_signum = $w->signal ($new_signal) |
331 | |
662 | |
332 | Returns the previously set signal (always as a number not name) and |
663 | Returns the previously set signal (always as a number not name) and |
333 | optionally set a new one. |
664 | optionally set a new one. |
334 | |
665 | |
|
|
666 | =back |
335 | |
667 | |
|
|
668 | |
|
|
669 | =head3 CHILD WATCHERS - watch out for process status changes |
|
|
670 | |
|
|
671 | =over 4 |
|
|
672 | |
336 | =item $w = EV::child $pid, $callback |
673 | =item $w = EV::child $pid, $trace, $callback |
337 | |
674 | |
338 | =item $w = EV::child_ns $pid, $callback |
675 | =item $w = EV::child_ns $pid, $trace, $callback |
|
|
676 | |
|
|
677 | =item $w = $loop->child ($pid, $trace, $callback) |
|
|
678 | |
|
|
679 | =item $w = $loop->child_ns ($pid, $trace, $callback) |
339 | |
680 | |
340 | Call the callback when a status change for pid C<$pid> (or any pid |
681 | Call the callback when a status change for pid C<$pid> (or any pid |
341 | if C<$pid> is 0) has been received. More precisely: when the process |
682 | if C<$pid> is 0) has been received (a status change happens when the |
|
|
683 | process terminates or is killed, or, when trace is true, additionally when |
|
|
684 | it is stopped or continued). More precisely: when the process receives |
342 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status for all |
685 | a C<SIGCHLD>, EV will fetch the outstanding exit/wait status for all |
343 | changed/zombie children and call the callback. |
686 | changed/zombie children and call the callback. |
344 | |
687 | |
345 | Unlike all other callbacks, this callback will be called with an |
688 | It is valid (and fully supported) to install a child watcher after a child |
346 | additional third argument which is the exit status. See the C<waitpid> |
689 | has exited but before the event loop has started its next iteration (for |
347 | function for details. |
690 | example, first you C<fork>, then the new child process might exit, and |
|
|
691 | only then do you install a child watcher in the parent for the new pid). |
348 | |
692 | |
|
|
693 | You can access both exit (or tracing) status and pid by using the |
|
|
694 | C<rstatus> and C<rpid> methods on the watcher object. |
|
|
695 | |
349 | You can have as many pid watchers per pid as you want. |
696 | You can have as many pid watchers per pid as you want, they will all be |
|
|
697 | called. |
350 | |
698 | |
351 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
699 | The C<child_ns> variant doesn't start (activate) the newly created watcher. |
352 | |
700 | |
353 | =item $w->set ($pid) |
701 | =item $w->set ($pid, $trace) |
354 | |
702 | |
355 | Reconfigures the watcher, see the constructor above for details. Can be at |
703 | Reconfigures the watcher, see the constructor above for details. Can be called at |
356 | any time. |
704 | any time. |
357 | |
705 | |
358 | =item $current_pid = $w->pid |
706 | =item $current_pid = $w->pid |
359 | |
707 | |
360 | =item $old_pid = $w->pid ($new_pid) |
|
|
361 | |
|
|
362 | Returns the previously set process id and optionally set a new one. |
708 | Returns the previously set process id and optionally set a new one. |
363 | |
709 | |
|
|
710 | =item $exit_status = $w->rstatus |
|
|
711 | |
|
|
712 | Return the exit/wait status (as returned by waitpid, see the waitpid entry |
|
|
713 | in perlfunc). |
|
|
714 | |
|
|
715 | =item $pid = $w->rpid |
|
|
716 | |
|
|
717 | Return the pid of the awaited child (useful when you have installed a |
|
|
718 | watcher for all pids). |
|
|
719 | |
|
|
720 | =back |
|
|
721 | |
|
|
722 | |
|
|
723 | =head3 STAT WATCHERS - did the file attributes just change? |
|
|
724 | |
|
|
725 | =over 4 |
|
|
726 | |
|
|
727 | =item $w = EV::stat $path, $interval, $callback |
|
|
728 | |
|
|
729 | =item $w = EV::stat_ns $path, $interval, $callback |
|
|
730 | |
|
|
731 | =item $w = $loop->stat ($path, $interval, $callback) |
|
|
732 | |
|
|
733 | =item $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
734 | |
|
|
735 | Call the callback when a file status change has been detected on |
|
|
736 | C<$path>. The C<$path> does not need to exist, changing from "path exists" |
|
|
737 | to "path does not exist" is a status change like any other. |
|
|
738 | |
|
|
739 | The C<$interval> is a recommended polling interval for systems where |
|
|
740 | OS-supported change notifications don't exist or are not supported. If |
|
|
741 | you use C<0> then an unspecified default is used (which is highly |
|
|
742 | recommended!), which is to be expected to be around five seconds usually. |
|
|
743 | |
|
|
744 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
745 | as even with OS-supported change notifications, this can be |
|
|
746 | resource-intensive. |
|
|
747 | |
|
|
748 | The C<stat_ns> variant doesn't start (activate) the newly created watcher. |
|
|
749 | |
|
|
750 | =item ... = $w->stat |
|
|
751 | |
|
|
752 | This call is very similar to the perl C<stat> built-in: It stats (using |
|
|
753 | C<lstat>) the path specified in the watcher and sets perls stat cache (as |
|
|
754 | well as EV's idea of the current stat values) to the values found. |
|
|
755 | |
|
|
756 | In scalar context, a boolean is return indicating success or failure of |
|
|
757 | the stat. In list context, the same 13-value list as with stat is returned |
|
|
758 | (except that the blksize and blocks fields are not reliable). |
|
|
759 | |
|
|
760 | In the case of an error, errno is set to C<ENOENT> (regardless of the |
|
|
761 | actual error value) and the C<nlink> value is forced to zero (if the stat |
|
|
762 | was successful then nlink is guaranteed to be non-zero). |
|
|
763 | |
|
|
764 | See also the next two entries for more info. |
|
|
765 | |
|
|
766 | =item ... = $w->attr |
|
|
767 | |
|
|
768 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
769 | the values most recently detected by EV. See the next entry for more info. |
|
|
770 | |
|
|
771 | =item ... = $w->prev |
|
|
772 | |
|
|
773 | Just like C<< $w->stat >>, but without the initial stat'ing: this returns |
|
|
774 | the previous set of values, before the change. |
|
|
775 | |
|
|
776 | That is, when the watcher callback is invoked, C<< $w->prev >> will be set |
|
|
777 | to the values found I<before> a change was detected, while C<< $w->attr >> |
|
|
778 | returns the values found leading to the change detection. The difference (if any) |
|
|
779 | between C<prev> and C<attr> is what triggered the callback. |
|
|
780 | |
|
|
781 | If you did something to the filesystem object and do not want to trigger |
|
|
782 | yet another change, you can call C<stat> to update EV's idea of what the |
|
|
783 | current attributes are. |
|
|
784 | |
|
|
785 | =item $w->set ($path, $interval) |
|
|
786 | |
|
|
787 | Reconfigures the watcher, see the constructor above for details. Can be |
|
|
788 | called at any time. |
|
|
789 | |
|
|
790 | =item $current_path = $w->path |
|
|
791 | |
|
|
792 | =item $old_path = $w->path ($new_path) |
|
|
793 | |
|
|
794 | Returns the previously set path and optionally set a new one. |
|
|
795 | |
|
|
796 | =item $current_interval = $w->interval |
|
|
797 | |
|
|
798 | =item $old_interval = $w->interval ($new_interval) |
|
|
799 | |
|
|
800 | Returns the previously set interval and optionally set a new one. Can be |
|
|
801 | used to query the actual interval used. |
|
|
802 | |
|
|
803 | =back |
|
|
804 | |
|
|
805 | |
|
|
806 | =head3 IDLE WATCHERS - when you've got nothing better to do... |
|
|
807 | |
|
|
808 | =over 4 |
364 | |
809 | |
365 | =item $w = EV::idle $callback |
810 | =item $w = EV::idle $callback |
366 | |
811 | |
367 | =item $w = EV::idle_ns $callback |
812 | =item $w = EV::idle_ns $callback |
368 | |
813 | |
369 | Call the callback when there are no pending io, timer/periodic, signal or |
814 | =item $w = $loop->idle ($callback) |
370 | child events, i.e. when the process is idle. |
815 | |
|
|
816 | =item $w = $loop->idle_ns ($callback) |
|
|
817 | |
|
|
818 | Call the callback when there are no other pending watchers of the same or |
|
|
819 | higher priority (excluding check, prepare and other idle watchers of the |
|
|
820 | same or lower priority, of course). They are called idle watchers because |
|
|
821 | when the watcher is the highest priority pending event in the process, the |
|
|
822 | process is considered to be idle at that priority. |
|
|
823 | |
|
|
824 | If you want a watcher that is only ever called when I<no> other events are |
|
|
825 | outstanding you have to set the priority to C<EV::MINPRI>. |
371 | |
826 | |
372 | The process will not block as long as any idle watchers are active, and |
827 | The process will not block as long as any idle watchers are active, and |
373 | they will be called repeatedly until stopped. |
828 | they will be called repeatedly until stopped. |
374 | |
829 | |
|
|
830 | For example, if you have idle watchers at priority C<0> and C<1>, and |
|
|
831 | an I/O watcher at priority C<0>, then the idle watcher at priority C<1> |
|
|
832 | and the I/O watcher will always run when ready. Only when the idle watcher |
|
|
833 | at priority C<1> is stopped and the I/O watcher at priority C<0> is not |
|
|
834 | pending with the C<0>-priority idle watcher be invoked. |
|
|
835 | |
375 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
836 | The C<idle_ns> variant doesn't start (activate) the newly created watcher. |
376 | |
837 | |
|
|
838 | =back |
|
|
839 | |
|
|
840 | |
|
|
841 | =head3 PREPARE WATCHERS - customise your event loop! |
|
|
842 | |
|
|
843 | =over 4 |
377 | |
844 | |
378 | =item $w = EV::prepare $callback |
845 | =item $w = EV::prepare $callback |
379 | |
846 | |
380 | =item $w = EV::prepare_ns $callback |
847 | =item $w = EV::prepare_ns $callback |
|
|
848 | |
|
|
849 | =item $w = $loop->prepare ($callback) |
|
|
850 | |
|
|
851 | =item $w = $loop->prepare_ns ($callback) |
381 | |
852 | |
382 | Call the callback just before the process would block. You can still |
853 | Call the callback just before the process would block. You can still |
383 | create/modify any watchers at this point. |
854 | create/modify any watchers at this point. |
384 | |
855 | |
385 | See the EV::check watcher, below, for explanations and an example. |
856 | See the EV::check watcher, below, for explanations and an example. |
386 | |
857 | |
387 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
858 | The C<prepare_ns> variant doesn't start (activate) the newly created watcher. |
388 | |
859 | |
|
|
860 | =back |
|
|
861 | |
|
|
862 | |
|
|
863 | =head3 CHECK WATCHERS - customise your event loop even more! |
|
|
864 | |
|
|
865 | =over 4 |
389 | |
866 | |
390 | =item $w = EV::check $callback |
867 | =item $w = EV::check $callback |
391 | |
868 | |
392 | =item $w = EV::check_ns $callback |
869 | =item $w = EV::check_ns $callback |
|
|
870 | |
|
|
871 | =item $w = $loop->check ($callback) |
|
|
872 | |
|
|
873 | =item $w = $loop->check_ns ($callback) |
393 | |
874 | |
394 | Call the callback just after the process wakes up again (after it has |
875 | Call the callback just after the process wakes up again (after it has |
395 | gathered events), but before any other callbacks have been invoked. |
876 | gathered events), but before any other callbacks have been invoked. |
396 | |
877 | |
397 | This is used to integrate other event-based software into the EV |
878 | This is used to integrate other event-based software into the EV |
… | |
… | |
405 | # do nothing unless active |
886 | # do nothing unless active |
406 | $dispatcher->{_event_queue_h} |
887 | $dispatcher->{_event_queue_h} |
407 | or return; |
888 | or return; |
408 | |
889 | |
409 | # make the dispatcher handle any outstanding stuff |
890 | # make the dispatcher handle any outstanding stuff |
|
|
891 | ... not shown |
410 | |
892 | |
411 | # create an IO watcher for each and every socket |
893 | # create an I/O watcher for each and every socket |
412 | @snmp_watcher = ( |
894 | @snmp_watcher = ( |
413 | (map { EV::io $_, EV::READ, sub { } } |
895 | (map { EV::io $_, EV::READ, sub { } } |
414 | keys %{ $dispatcher->{_descriptors} }), |
896 | keys %{ $dispatcher->{_descriptors} }), |
|
|
897 | |
|
|
898 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
899 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
900 | 0, sub { }, |
415 | ); |
901 | ); |
416 | |
|
|
417 | # if there are any timeouts, also create a timer |
|
|
418 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
419 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
420 | }; |
902 | }; |
421 | |
903 | |
422 | The callbacks are irrelevant, the only purpose of those watchers is |
904 | The callbacks are irrelevant (and are not even being called), the |
423 | to wake up the process as soon as one of those events occurs (socket |
905 | only purpose of those watchers is to wake up the process as soon as |
424 | readable, or timer timed out). The corresponding EV::check watcher will then |
906 | one of those events occurs (socket readable, or timer timed out). The |
425 | clean up: |
907 | corresponding EV::check watcher will then clean up: |
426 | |
908 | |
427 | our $snmp_check = EV::check sub { |
909 | our $snmp_check = EV::check sub { |
428 | # destroy all watchers |
910 | # destroy all watchers |
429 | @snmp_watcher = (); |
911 | @snmp_watcher = (); |
430 | |
912 | |
431 | # make the dispatcher handle any new stuff |
913 | # make the dispatcher handle any new stuff |
|
|
914 | ... not shown |
432 | }; |
915 | }; |
433 | |
916 | |
434 | The callbacks of the created watchers will not be called as the watchers |
917 | The callbacks of the created watchers will not be called as the watchers |
435 | are destroyed before this cna happen (remember EV::check gets called |
918 | are destroyed before this cna happen (remember EV::check gets called |
436 | first). |
919 | first). |
437 | |
920 | |
438 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
921 | The C<check_ns> variant doesn't start (activate) the newly created watcher. |
439 | |
922 | |
440 | =back |
923 | =back |
441 | |
924 | |
|
|
925 | |
|
|
926 | =head3 FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
927 | |
|
|
928 | Fork watchers are called when a C<fork ()> was detected. The invocation |
|
|
929 | is done before the event loop blocks next and before C<check> watchers |
|
|
930 | are being called, and only in the child after the fork. |
|
|
931 | |
|
|
932 | =over 4 |
|
|
933 | |
|
|
934 | =item $w = EV::fork $callback |
|
|
935 | |
|
|
936 | =item $w = EV::fork_ns $callback |
|
|
937 | |
|
|
938 | =item $w = $loop->fork ($callback) |
|
|
939 | |
|
|
940 | =item $w = $loop->fork_ns ($callback) |
|
|
941 | |
|
|
942 | Call the callback before the event loop is resumed in the child process |
|
|
943 | after a fork. |
|
|
944 | |
|
|
945 | The C<fork_ns> variant doesn't start (activate) the newly created watcher. |
|
|
946 | |
|
|
947 | =back |
|
|
948 | |
|
|
949 | |
|
|
950 | =head3 EMBED WATCHERS - when one backend isn't enough... |
|
|
951 | |
|
|
952 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
953 | into another (currently only IO events are supported in the embedded |
|
|
954 | loop, other types of watchers might be handled in a delayed or incorrect |
|
|
955 | fashion and must not be used). |
|
|
956 | |
|
|
957 | See the libev documentation at |
|
|
958 | L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code_when_one_backend_> |
|
|
959 | for more details. |
|
|
960 | |
|
|
961 | In short, this watcher is most useful on BSD systems without working |
|
|
962 | kqueue to still be able to handle a large number of sockets: |
|
|
963 | |
|
|
964 | my $socket_loop; |
|
|
965 | |
|
|
966 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
967 | if ( |
|
|
968 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
969 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
970 | ) { |
|
|
971 | # use kqueue for sockets |
|
|
972 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
973 | } |
|
|
974 | |
|
|
975 | # use the default loop otherwise |
|
|
976 | $socket_loop ||= EV::default_loop; |
|
|
977 | |
|
|
978 | =over 4 |
|
|
979 | |
|
|
980 | =item $w = EV::embed $otherloop, $callback |
|
|
981 | |
|
|
982 | =item $w = EV::embed_ns $otherloop, $callback |
|
|
983 | |
|
|
984 | =item $w = $loop->embed ($otherloop, $callback) |
|
|
985 | |
|
|
986 | =item $w = $loop->embed_ns ($otherloop, $callback) |
|
|
987 | |
|
|
988 | Call the callback when the embedded event loop (C<$otherloop>) has any |
|
|
989 | I/O activity. The C<$callback> should alwas be specified as C<undef> in |
|
|
990 | this version of EV, which means the embedded event loop will be managed |
|
|
991 | automatically. |
|
|
992 | |
|
|
993 | The C<embed_ns> variant doesn't start (activate) the newly created watcher. |
|
|
994 | |
|
|
995 | =back |
|
|
996 | |
|
|
997 | =head3 ASYNC WATCHERS - how to wake up another event loop |
|
|
998 | |
|
|
999 | Async watchers are provided by EV, but have little use in perl directly, as perl |
|
|
1000 | neither supports threads nor direct access to signal handlers or other |
|
|
1001 | contexts where they could be of value. |
|
|
1002 | |
|
|
1003 | It is, however, possible to use them from the XS level. |
|
|
1004 | |
|
|
1005 | Please see the libev documentation for further details. |
|
|
1006 | |
|
|
1007 | =over 4 |
|
|
1008 | |
|
|
1009 | =item $w = EV::async $callback |
|
|
1010 | |
|
|
1011 | =item $w = EV::async_ns $callback |
|
|
1012 | |
|
|
1013 | =item $w->send |
|
|
1014 | |
|
|
1015 | =item $bool = $w->async_pending |
|
|
1016 | |
|
|
1017 | =back |
|
|
1018 | |
|
|
1019 | |
|
|
1020 | =head1 PERL SIGNALS |
|
|
1021 | |
|
|
1022 | While Perl signal handling (C<%SIG>) is not affected by EV, the behaviour |
|
|
1023 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
1024 | handled when Perl runs, which means your signal handler might be invoked |
|
|
1025 | only the next time an event callback is invoked. |
|
|
1026 | |
|
|
1027 | The solution is to use EV signal watchers (see C<EV::signal>), which will |
|
|
1028 | ensure proper operations with regards to other event watchers. |
|
|
1029 | |
|
|
1030 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
1031 | to be called on every event loop iteration by installing a C<EV::check> |
|
|
1032 | watcher: |
|
|
1033 | |
|
|
1034 | my $async_check = EV::check sub { }; |
|
|
1035 | |
|
|
1036 | This ensures that perl gets into control for a short time to handle any |
|
|
1037 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
1038 | |
442 | =head1 THREADS |
1039 | =head1 THREADS |
443 | |
1040 | |
444 | Threads are not supported by this in any way. Perl pseudo-threads is evil |
1041 | Threads are not supported by this module in any way. Perl pseudo-threads |
445 | stuff and must die. |
1042 | is evil stuff and must die. As soon as Perl gains real threads I will work |
|
|
1043 | on thread support for it. |
|
|
1044 | |
|
|
1045 | =head1 FORK |
|
|
1046 | |
|
|
1047 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
1048 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
1049 | not supported and usually destructive). Libev makes it possible to work |
|
|
1050 | around this by having a function that recreates the kernel state after |
|
|
1051 | fork in the child. |
|
|
1052 | |
|
|
1053 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
1054 | functionality to do this automatically for you. This function is quite |
|
|
1055 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
1056 | negligible, because everything the function currently does is set a flag |
|
|
1057 | that is checked only when the event loop gets used the next time, so when |
|
|
1058 | you do fork but not use EV, the overhead is minimal. |
|
|
1059 | |
|
|
1060 | On win32, there is no notion of fork so all this doesn't apply, of course. |
446 | |
1061 | |
447 | =cut |
1062 | =cut |
448 | |
1063 | |
449 | our $DIED = sub { |
1064 | our $DIED = sub { |
450 | warn "EV: error in callback (ignoring): $@"; |
1065 | warn "EV: error in callback (ignoring): $@"; |
451 | }; |
1066 | }; |
452 | |
1067 | |
453 | init; |
1068 | default_loop |
454 | |
1069 | or die 'EV: cannot initialise libev backend. bad $ENV{LIBEV_FLAGS}?'; |
455 | push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"]; |
|
|
456 | |
1070 | |
457 | 1; |
1071 | 1; |
458 | |
1072 | |
459 | =head1 SEE ALSO |
1073 | =head1 SEE ALSO |
460 | |
1074 | |
461 | L<EV::DNS>, L<EV::AnyEvent>. |
1075 | L<EV::ADNS> (asynchronous DNS), L<Glib::EV> (makes Glib/Gtk2 use EV as |
|
|
1076 | event loop), L<EV::Glib> (embed Glib into EV), L<Coro::EV> (efficient |
|
|
1077 | coroutines with EV), L<Net::SNMP::EV> (asynchronous SNMP), L<AnyEvent> for |
|
|
1078 | event-loop agnostic and portable event driven programming. |
462 | |
1079 | |
463 | =head1 AUTHOR |
1080 | =head1 AUTHOR |
464 | |
1081 | |
465 | Marc Lehmann <schmorp@schmorp.de> |
1082 | Marc Lehmann <schmorp@schmorp.de> |
466 | http://home.schmorp.de/ |
1083 | http://home.schmorp.de/ |
467 | |
1084 | |
468 | =cut |
1085 | =cut |
469 | |
1086 | |