1 | NAME |
1 | NAME |
2 | EV - perl interface to libev, a high performance full-featured event |
2 | EV - perl interface to libev, a high performance full-featured event |
3 | loop |
3 | loop |
4 | |
4 | |
5 | SYNOPSIS |
5 | SYNOPSIS |
6 | use EV; |
6 | use EV; |
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7 | |
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8 | # TIMERS |
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9 | |
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10 | my $w = EV::timer 2, 0, sub { |
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11 | warn "is called after 2s"; |
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12 | }; |
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13 | |
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14 | my $w = EV::timer 2, 2, sub { |
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15 | warn "is called roughly every 2s (repeat = 2)"; |
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16 | }; |
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17 | |
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18 | undef $w; # destroy event watcher again |
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19 | |
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20 | my $w = EV::periodic 0, 60, 0, sub { |
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21 | warn "is called every minute, on the minute, exactly"; |
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22 | }; |
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23 | |
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24 | # IO |
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25 | |
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26 | my $w = EV::io *STDIN, EV::READ, sub { |
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27 | my ($w, $revents) = @_; # all callbacks receive the watcher and event mask |
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28 | warn "stdin is readable, you entered: ", <STDIN>; |
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29 | }; |
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30 | |
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31 | # SIGNALS |
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32 | |
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33 | my $w = EV::signal 'QUIT', sub { |
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34 | warn "sigquit received\n"; |
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35 | }; |
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36 | |
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37 | # CHILD/PID STATUS CHANGES |
7 | |
38 | |
8 | # TIMERS |
39 | my $w = EV::child 666, 0, sub { |
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40 | my ($w, $revents) = @_; |
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41 | my $status = $w->rstatus; |
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42 | }; |
9 | |
43 | |
10 | my $w = EV::timer 2, 0, sub { |
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11 | warn "is called after 2s"; |
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12 | }; |
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13 | |
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14 | my $w = EV::timer 2, 1, sub { |
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15 | warn "is called roughly every 2s (repeat = 1)"; |
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16 | }; |
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17 | |
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18 | undef $w; # destroy event watcher again |
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19 | |
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20 | my $w = EV::periodic 0, 60, sub { |
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21 | warn "is called every minute, on the minute, exactly"; |
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22 | }; |
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23 | |
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24 | # IO |
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25 | |
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26 | my $w = EV::io *STDIN, EV::READ, sub { |
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27 | my ($w, $revents) = @_; # all callbacks get the watcher object and event mask |
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28 | warn "stdin is readable, you entered: ", <STDIN>; |
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29 | }; |
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30 | |
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31 | # SIGNALS |
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32 | |
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33 | my $w = EV::signal 'QUIT', sub { |
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34 | warn "sigquit received\n"; |
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35 | }; |
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36 | |
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37 | my $w = EV::signal 3, sub { |
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38 | warn "sigquit received (this is GNU/Linux, right?)\n"; |
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39 | }; |
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40 | |
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41 | # CHILD/PID STATUS CHANGES |
44 | # STAT CHANGES |
42 | |
45 | my $w = EV::stat "/etc/passwd", 10, sub { |
43 | my $w = EV::child 666, sub { |
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44 | my ($w, $revents) = @_; |
46 | my ($w, $revents) = @_; |
45 | # my $pid = $w->rpid; |
47 | warn $w->path, " has changed somehow.\n"; |
46 | my $status = $w->rstatus; |
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47 | }; |
48 | }; |
48 | |
49 | |
49 | # MAINLOOP |
50 | # MAINLOOP |
50 | EV::loop; # loop until EV::loop_done is called |
51 | EV::loop; # loop until EV::unloop is called or all watchers stop |
51 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
52 | EV::loop EV::LOOP_ONESHOT; # block until at least one event could be handled |
52 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
53 | EV::loop EV::LOOP_NONBLOCK; # try to handle same events, but do not block |
53 | |
54 | |
54 | DESCRIPTION |
55 | DESCRIPTION |
55 | This module provides an interface to libev |
56 | This module provides an interface to libev |
56 | (<http://software.schmorp.de/pkg/libev.html>). |
57 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
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58 | below is comprehensive, one might also consult the documentation of |
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59 | libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or |
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60 | perldoc EV::libev) for more subtle details on watcher semantics or some |
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61 | discussion on the available backends, or how to force a specific backend |
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62 | with "LIBEV_FLAGS", or just about in any case because it has much more |
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63 | detailed information. |
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64 | |
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65 | This module is very fast and scalable. It is actually so fast that you |
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66 | can use it through the AnyEvent module, stay portable to other event |
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67 | loops (if you don't rely on any watcher types not available through it) |
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68 | and still be faster than with any other event loop currently supported |
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69 | in Perl. |
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70 | |
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71 | MODULE EXPORTS |
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72 | This module does not export any symbols. |
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73 | |
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74 | EVENT LOOPS |
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75 | EV supports multiple event loops: There is a single "default event loop" |
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76 | that can handle everything including signals and child watchers, and any |
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77 | number of "dynamic event loops" that can use different backends (with |
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78 | various limitations), but no child and signal watchers. |
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79 | |
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80 | You do not have to do anything to create the default event loop: When |
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81 | the module is loaded a suitable backend is selected on the premise of |
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82 | selecting a working backend (which for example rules out kqueue on most |
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83 | BSDs). Modules should, unless they have "special needs" always use the |
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84 | default loop as this is fastest (perl-wise), best supported by other |
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85 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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86 | |
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87 | For specific programs you can create additional event loops dynamically. |
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88 | |
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89 | If you want to take advantage of kqueue (which often works properly for |
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90 | sockets only) even though the default loop doesn't enable it, you can |
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91 | *embed* a kqueue loop into the default loop: running the default loop |
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92 | will then also service the kqueue loop to some extent. See the example |
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93 | in the section about embed watchers for an example on how to achieve |
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94 | that. |
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95 | |
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96 | $loop = new EV::Loop [$flags] |
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97 | Create a new event loop as per the specified flags. Please refer to |
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98 | the "ev_loop_new ()" function description in the libev documentation |
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99 | (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI |
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100 | ONS>, or locally-installed as EV::libev manpage) for more info. |
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101 | |
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102 | The loop will automatically be destroyed when it is no longer |
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103 | referenced by any watcher and the loop object goes out of scope. |
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104 | |
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105 | If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK" |
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106 | is recommended, as only the default event loop is protected by this |
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107 | module. If you *are* embedding this loop in the default loop, this |
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108 | is not necessary, as "EV::embed" automatically does the right thing |
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109 | on fork. |
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110 | |
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111 | $loop->loop_fork |
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112 | Must be called after a fork in the child, before entering or |
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113 | continuing the event loop. An alternative is to use |
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114 | "EV::FLAG_FORKCHECK" which calls this function automatically, at |
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115 | some performance loss (refer to the libev documentation). |
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116 | |
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117 | $loop->loop_verify |
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118 | Calls "ev_verify" to make internal consistency checks (for debugging |
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119 | libev) and abort the program if any data structures were found to be |
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120 | corrupted. |
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121 | |
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122 | $loop = EV::default_loop [$flags] |
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123 | Return the default loop (which is a singleton object). Since this |
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124 | module already creates the default loop with default flags, |
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125 | specifying flags here will not have any effect unless you destroy |
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126 | the default loop first, which isn't supported. So in short: don't do |
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127 | it, and if you break it, you get to keep the pieces. |
57 | |
128 | |
58 | BASIC INTERFACE |
129 | BASIC INTERFACE |
59 | $EV::DIED |
130 | $EV::DIED |
60 | Must contain a reference to a function that is called when a |
131 | Must contain a reference to a function that is called when a |
61 | callback throws an exception (with $@ containing thr error). The |
132 | callback throws an exception (with $@ containing the error). The |
62 | default prints an informative message and continues. |
133 | default prints an informative message and continues. |
63 | |
134 | |
64 | If this callback throws an exception it will be silently ignored. |
135 | If this callback throws an exception it will be silently ignored. |
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136 | |
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137 | $flags = EV::supported_backends |
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138 | $flags = EV::recommended_backends |
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139 | $flags = EV::embeddable_backends |
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140 | Returns the set (see "EV::BACKEND_*" flags) of backends supported by |
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141 | this instance of EV, the set of recommended backends (supposed to be |
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142 | good) for this platform and the set of embeddable backends (see |
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143 | EMBED WATCHERS). |
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144 | |
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145 | EV::sleep $seconds |
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146 | Block the process for the given number of (fractional) seconds. |
65 | |
147 | |
66 | $time = EV::time |
148 | $time = EV::time |
67 | Returns the current time in (fractional) seconds since the epoch. |
149 | Returns the current time in (fractional) seconds since the epoch. |
68 | |
150 | |
69 | $time = EV::now |
151 | $time = EV::now |
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152 | $time = $loop->now |
70 | Returns the time the last event loop iteration has been started. |
153 | Returns the time the last event loop iteration has been started. |
71 | This is the time that (relative) timers are based on, and refering |
154 | This is the time that (relative) timers are based on, and referring |
72 | to it is usually faster then calling EV::time. |
155 | to it is usually faster then calling EV::time. |
73 | |
156 | |
74 | $method = EV::ev_method |
157 | EV::now_update |
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158 | $loop->now_update |
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159 | Establishes the current time by querying the kernel, updating the |
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160 | time returned by "EV::now" in the progress. This is a costly |
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161 | operation and is usually done automatically within "EV::loop". |
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162 | |
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163 | This function is rarely useful, but when some event callback runs |
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164 | for a very long time without entering the event loop, updating |
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165 | libev's idea of the current time is a good idea. |
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166 | |
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167 | EV::suspend |
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168 | $loop->suspend |
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169 | EV::resume |
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170 | $loop->resume |
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171 | These two functions suspend and resume a loop, for use when the loop |
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172 | is not used for a while and timeouts should not be processed. |
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173 | |
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174 | A typical use case would be an interactive program such as a game: |
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175 | When the user presses "^Z" to suspend the game and resumes it an |
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176 | hour later it would be best to handle timeouts as if no time had |
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177 | actually passed while the program was suspended. This can be |
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178 | achieved by calling "suspend" in your "SIGTSTP" handler, sending |
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179 | yourself a "SIGSTOP" and calling "resume" directly afterwards to |
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180 | resume timer processing. |
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181 | |
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182 | Effectively, all "timer" watchers will be delayed by the time spend |
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183 | between "suspend" and "resume", and all "periodic" watchers will be |
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184 | rescheduled (that is, they will lose any events that would have |
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185 | occured while suspended). |
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186 | |
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187 | After calling "suspend" you must not call *any* function on the |
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188 | given loop other than "resume", and you must not call "resume" |
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189 | without a previous call to "suspend". |
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190 | |
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191 | Calling "suspend"/"resume" has the side effect of updating the event |
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192 | loop time (see "now_update"). |
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193 | |
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194 | $backend = EV::backend |
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195 | $backend = $loop->backend |
75 | Returns an integer describing the backend used by libev |
196 | Returns an integer describing the backend used by libev |
76 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
197 | (EV::BACKEND_SELECT or EV::BACKEND_EPOLL). |
77 | |
198 | |
78 | EV::loop [$flags] |
199 | EV::loop [$flags] |
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200 | $loop->loop ([$flags]) |
79 | Begin checking for events and calling callbacks. It returns when a |
201 | Begin checking for events and calling callbacks. It returns when a |
80 | callback calls EV::loop_done. |
202 | callback calls EV::unloop. |
81 | |
203 | |
82 | The $flags argument can be one of the following: |
204 | The $flags argument can be one of the following: |
83 | |
205 | |
84 | 0 as above |
206 | 0 as above |
85 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
207 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
86 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
208 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
87 | |
209 | |
88 | EV::loop_done [$how] |
210 | EV::unloop [$how] |
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211 | $loop->unloop ([$how]) |
89 | When called with no arguments or an argument of 1, makes the |
212 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
90 | innermost call to EV::loop return. |
213 | makes the innermost call to EV::loop return. |
91 | |
214 | |
92 | When called with an agrument of 2, all calls to EV::loop will return |
215 | When called with an argument of EV::UNLOOP_ALL, all calls to |
93 | as fast as possible. |
216 | EV::loop will return as fast as possible. |
94 | |
217 | |
95 | WATCHER |
218 | $count = EV::loop_count |
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219 | $count = $loop->loop_count |
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220 | Return the number of times the event loop has polled for new events. |
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221 | Sometimes useful as a generation counter. |
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222 | |
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223 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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224 | $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
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225 | This function rolls together an I/O and a timer watcher for a single |
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226 | one-shot event without the need for managing a watcher object. |
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227 | |
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228 | If $fh_or_undef is a filehandle or file descriptor, then $events |
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229 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
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230 | "EV::READ | EV::WRITE", indicating the type of I/O event you want to |
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231 | wait for. If you do not want to wait for some I/O event, specify |
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232 | "undef" for $fh_or_undef and 0 for $events). |
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233 | |
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234 | If timeout is "undef" or negative, then there will be no timeout. |
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235 | Otherwise a EV::timer with this value will be started. |
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236 | |
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237 | When an error occurs or either the timeout or I/O watcher triggers, |
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238 | then the callback will be called with the received event set (in |
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239 | general you can expect it to be a combination of "EV::ERROR", |
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240 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
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241 | |
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242 | EV::once doesn't return anything: the watchers stay active till |
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243 | either of them triggers, then they will be stopped and freed, and |
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244 | the callback invoked. |
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245 | |
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246 | EV::feed_fd_event ($fd, $revents) |
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247 | $loop->feed_fd_event ($fd, $revents) |
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248 | Feed an event on a file descriptor into EV. EV will react to this |
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249 | call as if the readyness notifications specified by $revents (a |
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250 | combination of "EV::READ" and "EV::WRITE") happened on the file |
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251 | descriptor $fd. |
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252 | |
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253 | EV::feed_signal_event ($signal) |
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254 | Feed a signal event into EV. EV will react to this call as if the |
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255 | signal specified by $signal had occured. |
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256 | |
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257 | EV::set_io_collect_interval $time |
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258 | $loop->set_io_collect_interval ($time) |
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259 | EV::set_timeout_collect_interval $time |
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260 | $loop->set_timeout_collect_interval ($time) |
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261 | These advanced functions set the minimum block interval when polling |
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262 | for I/O events and the minimum wait interval for timer events. See |
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263 | the libev documentation at |
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264 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT |
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265 | ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more |
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266 | detailed discussion. |
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267 | |
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268 | $count = EV::pending_count |
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269 | $count = $loop->pending_count |
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270 | Returns the number of currently pending watchers. |
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271 | |
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272 | EV::invoke_pending |
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273 | $loop->invoke_pending |
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274 | Invoke all currently pending watchers. |
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275 | |
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276 | WATCHER OBJECTS |
96 | A watcher is an object that gets created to record your interest in some |
277 | A watcher is an object that gets created to record your interest in some |
97 | event. For instance, if you want to wait for STDIN to become readable, |
278 | event. For instance, if you want to wait for STDIN to become readable, |
98 | you would create an EV::io watcher for that: |
279 | you would create an EV::io watcher for that: |
99 | |
280 | |
100 | my $watcher = EV::io *STDIN, EV::READ, sub { |
281 | my $watcher = EV::io *STDIN, EV::READ, sub { |
101 | my ($watcher, $revents) = @_; |
282 | my ($watcher, $revents) = @_; |
102 | warn "yeah, STDIN should not be readable without blocking!\n" |
283 | warn "yeah, STDIN should now be readable without blocking!\n" |
103 | }; |
284 | }; |
104 | |
285 | |
105 | All watchers can be active (waiting for events) or inactive (paused). |
286 | All watchers can be active (waiting for events) or inactive (paused). |
106 | Only active watchers will have their callbacks invoked. All callbacks |
287 | Only active watchers will have their callbacks invoked. All callbacks |
107 | will be called with at least two arguments: the watcher and a bitmask of |
288 | will be called with at least two arguments: the watcher and a bitmask of |
108 | received events. |
289 | received events. |
109 | |
290 | |
110 | Each watcher type has its associated bit in revents, so you can use the |
291 | Each watcher type has its associated bit in revents, so you can use the |
111 | same callback for multiple watchers. The event mask is named after the |
292 | same callback for multiple watchers. The event mask is named after the |
112 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
293 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
113 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO |
294 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
114 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
295 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
115 | (which uses EV::TIMEOUT). |
296 | (which uses EV::TIMEOUT). |
116 | |
297 | |
117 | In the rare case where one wants to create a watcher but not start it at |
298 | In the rare case where one wants to create a watcher but not start it at |
118 | the same time, each constructor has a variant with a trailing "_ns" in |
299 | the same time, each constructor has a variant with a trailing "_ns" in |
… | |
… | |
124 | |
305 | |
125 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
306 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
126 | ->fh and so on) automatically stop and start it again if it is active, |
307 | ->fh and so on) automatically stop and start it again if it is active, |
127 | which means pending events get lost. |
308 | which means pending events get lost. |
128 | |
309 | |
129 | WATCHER TYPES |
310 | COMMON WATCHER METHODS |
130 | Now lets move to the existing watcher types and asociated methods. |
311 | This section lists methods common to all watchers. |
131 | |
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132 | The following methods are available for all watchers. Then followes a |
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133 | description of each watcher constructor (EV::io, EV::timer, |
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134 | EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and |
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135 | EV::check), followed by any type-specific methods (if any). |
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136 | |
312 | |
137 | $w->start |
313 | $w->start |
138 | Starts a watcher if it isn't active already. Does nothing to an |
314 | Starts a watcher if it isn't active already. Does nothing to an |
139 | already active watcher. By default, all watchers start out in the |
315 | already active watcher. By default, all watchers start out in the |
140 | active state (see the description of the "_ns" variants if you need |
316 | active state (see the description of the "_ns" variants if you need |
141 | stopped watchers). |
317 | stopped watchers). |
142 | |
318 | |
143 | $w->stop |
319 | $w->stop |
144 | Stop a watcher if it is active. Also clear any pending events |
320 | Stop a watcher if it is active. Also clear any pending events |
145 | (events that have been received but that didn't yet result in a |
321 | (events that have been received but that didn't yet result in a |
146 | callback invocation), regardless of wether the watcher was active or |
322 | callback invocation), regardless of whether the watcher was active |
147 | not. |
323 | or not. |
148 | |
324 | |
149 | $bool = $w->is_active |
325 | $bool = $w->is_active |
150 | Returns true if the watcher is active, false otherwise. |
326 | Returns true if the watcher is active, false otherwise. |
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327 | |
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328 | $current_data = $w->data |
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329 | $old_data = $w->data ($new_data) |
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330 | Queries a freely usable data scalar on the watcher and optionally |
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331 | changes it. This is a way to associate custom data with a watcher: |
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332 | |
|
|
333 | my $w = EV::timer 60, 0, sub { |
|
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334 | warn $_[0]->data; |
|
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335 | }; |
|
|
336 | $w->data ("print me!"); |
151 | |
337 | |
152 | $current_cb = $w->cb |
338 | $current_cb = $w->cb |
153 | $old_cb = $w->cb ($new_cb) |
339 | $old_cb = $w->cb ($new_cb) |
154 | Queries the callback on the watcher and optionally changes it. You |
340 | Queries the callback on the watcher and optionally changes it. You |
155 | can do this at any time without the watcher restarting. |
341 | can do this at any time without the watcher restarting. |
… | |
… | |
160 | Pending watchers with higher priority will be invoked first. The |
346 | Pending watchers with higher priority will be invoked first. The |
161 | valid range of priorities lies between EV::MAXPRI (default 2) and |
347 | valid range of priorities lies between EV::MAXPRI (default 2) and |
162 | EV::MINPRI (default -2). If the priority is outside this range it |
348 | EV::MINPRI (default -2). If the priority is outside this range it |
163 | will automatically be normalised to the nearest valid priority. |
349 | will automatically be normalised to the nearest valid priority. |
164 | |
350 | |
165 | The default priority of any newly-created weatcher is 0. |
351 | The default priority of any newly-created watcher is 0. |
166 | |
352 | |
|
|
353 | Note that the priority semantics have not yet been fleshed out and |
|
|
354 | are subject to almost certain change. |
|
|
355 | |
167 | $w->trigger ($revents) |
356 | $w->invoke ($revents) |
168 | Call the callback *now* with the given event mask. |
357 | Call the callback *now* with the given event mask. |
169 | |
358 | |
|
|
359 | $w->feed_event ($revents) |
|
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360 | Feed some events on this watcher into EV. EV will react to this call |
|
|
361 | as if the watcher had received the given $revents mask. |
|
|
362 | |
|
|
363 | $revents = $w->clear_pending |
|
|
364 | If the watcher is pending, this function clears its pending status |
|
|
365 | and returns its $revents bitset (as if its callback was invoked). If |
|
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366 | the watcher isn't pending it does nothing and returns 0. |
|
|
367 | |
|
|
368 | $previous_state = $w->keepalive ($bool) |
|
|
369 | Normally, "EV::loop" will return when there are no active watchers |
|
|
370 | (which is a "deadlock" because no progress can be made anymore). |
|
|
371 | This is convinient because it allows you to start your watchers (and |
|
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372 | your jobs), call "EV::loop" once and when it returns you know that |
|
|
373 | all your jobs are finished (or they forgot to register some watchers |
|
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374 | for their task :). |
|
|
375 | |
|
|
376 | Sometimes, however, this gets in your way, for example when the |
|
|
377 | module that calls "EV::loop" (usually the main program) is not the |
|
|
378 | same module as a long-living watcher (for example a DNS client |
|
|
379 | module written by somebody else even). Then you might want any |
|
|
380 | outstanding requests to be handled, but you would not want to keep |
|
|
381 | "EV::loop" from returning just because you happen to have this |
|
|
382 | long-running UDP port watcher. |
|
|
383 | |
|
|
384 | In this case you can clear the keepalive status, which means that |
|
|
385 | even though your watcher is active, it won't keep "EV::loop" from |
|
|
386 | returning. |
|
|
387 | |
|
|
388 | The initial value for keepalive is true (enabled), and you can |
|
|
389 | change it any time. |
|
|
390 | |
|
|
391 | Example: Register an I/O watcher for some UDP socket but do not keep |
|
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392 | the event loop from running just because of that watcher. |
|
|
393 | |
|
|
394 | my $udp_socket = ... |
|
|
395 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
|
|
396 | $udp_watcher->keepalive (0); |
|
|
397 | |
|
|
398 | $loop = $w->loop |
|
|
399 | Return the loop that this watcher is attached to. |
|
|
400 | |
|
|
401 | WATCHER TYPES |
|
|
402 | Each of the following subsections describes a single watcher type. |
|
|
403 | |
|
|
404 | I/O WATCHERS - is this file descriptor readable or writable? |
170 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
405 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
171 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
406 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
|
|
407 | $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
|
408 | $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
172 | As long as the returned watcher object is alive, call the $callback |
409 | As long as the returned watcher object is alive, call the $callback |
173 | when the events specified in $eventmask. |
410 | when at least one of events specified in $eventmask occurs. |
174 | |
411 | |
175 | The $eventmask can be one or more of these constants ORed together: |
412 | The $eventmask can be one or more of these constants ORed together: |
176 | |
413 | |
177 | EV::READ wait until read() wouldn't block anymore |
414 | EV::READ wait until read() wouldn't block anymore |
178 | EV::WRITE wait until write() wouldn't block anymore |
415 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
190 | |
427 | |
191 | $current_eventmask = $w->events |
428 | $current_eventmask = $w->events |
192 | $old_eventmask = $w->events ($new_eventmask) |
429 | $old_eventmask = $w->events ($new_eventmask) |
193 | Returns the previously set event mask and optionally set a new one. |
430 | Returns the previously set event mask and optionally set a new one. |
194 | |
431 | |
|
|
432 | TIMER WATCHERS - relative and optionally repeating timeouts |
195 | $w = EV::timer $after, $repeat, $callback |
433 | $w = EV::timer $after, $repeat, $callback |
196 | $w = EV::timer_ns $after, $repeat, $callback |
434 | $w = EV::timer_ns $after, $repeat, $callback |
197 | Calls the callback after $after seconds. If $repeat is non-zero, the |
435 | $w = $loop->timer ($after, $repeat, $callback) |
198 | timer will be restarted (with the $repeat value as $after) after the |
436 | $w = $loop->timer_ns ($after, $repeat, $callback) |
199 | callback returns. |
437 | Calls the callback after $after seconds (which may be fractional). |
|
|
438 | If $repeat is non-zero, the timer will be restarted (with the |
|
|
439 | $repeat value as $after) after the callback returns. |
200 | |
440 | |
201 | This means that the callback would be called roughly after $after |
441 | This means that the callback would be called roughly after $after |
202 | seconds, and then every $repeat seconds. "Roughly" because the time |
442 | seconds, and then every $repeat seconds. The timer does his best not |
203 | of callback processing is not taken into account, so the timer will |
443 | to drift, but it will not invoke the timer more often then once per |
204 | slowly drift. If that isn't acceptable, look at EV::periodic. |
444 | event loop iteration, and might drift in other cases. If that isn't |
|
|
445 | acceptable, look at EV::periodic, which can provide long-term stable |
|
|
446 | timers. |
205 | |
447 | |
206 | The timer is based on a monotonic clock, that is if somebody is |
448 | The timer is based on a monotonic clock, that is, if somebody is |
207 | sitting in front of the machine while the timer is running and |
449 | sitting in front of the machine while the timer is running and |
208 | changes the system clock, the timer will nevertheless run (roughly) |
450 | changes the system clock, the timer will nevertheless run (roughly) |
209 | the same time. |
451 | the same time. |
210 | |
452 | |
211 | The "timer_ns" variant doesn't start (activate) the newly created |
453 | The "timer_ns" variant doesn't start (activate) the newly created |
212 | watcher. |
454 | watcher. |
213 | |
455 | |
214 | $w->set ($after, $repeat) |
456 | $w->set ($after, $repeat) |
215 | Reconfigures the watcher, see the constructor above for details. Can |
457 | Reconfigures the watcher, see the constructor above for details. Can |
216 | be at any time. |
458 | be called at any time. |
217 | |
459 | |
218 | $w->again |
460 | $w->again |
219 | Similar to the "start" method, but has special semantics for |
461 | Similar to the "start" method, but has special semantics for |
220 | repeating timers: |
462 | repeating timers: |
221 | |
463 | |
|
|
464 | If the timer is active and non-repeating, it will be stopped. |
|
|
465 | |
222 | If the timer is active and repeating, reset the timeout to occur |
466 | If the timer is active and repeating, reset the timeout to occur |
223 | $repeat seconds after now. |
467 | $repeat seconds after now. |
224 | |
468 | |
225 | If the timer is active and non-repeating, it will be stopped. |
|
|
226 | |
|
|
227 | If the timer is in active and repeating, start it. |
469 | If the timer is inactive and repeating, start it using the repeat |
|
|
470 | value. |
228 | |
471 | |
229 | Otherwise do nothing. |
472 | Otherwise do nothing. |
230 | |
473 | |
231 | This behaviour is useful when you have a timeout for some IO |
474 | This behaviour is useful when you have a timeout for some IO |
232 | operation. You create a timer object with the same value for $after |
475 | operation. You create a timer object with the same value for $after |
233 | and $repeat, and then, in the read/write watcher, run the "again" |
476 | and $repeat, and then, in the read/write watcher, run the "again" |
234 | method on the timeout. |
477 | method on the timeout. |
235 | |
478 | |
|
|
479 | PERIODIC WATCHERS - to cron or not to cron? |
236 | $w = EV::periodic $at, $interval, $callback |
480 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
237 | $w = EV::periodic_ns $at, $interval, $callback |
481 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
238 | Similar to EV::timer, but the time is given as an absolute point in |
482 | $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
239 | time ($at), plus an optional $interval. |
483 | $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
|
|
484 | Similar to EV::timer, but is not based on relative timeouts but on |
|
|
485 | absolute times. Apart from creating "simple" timers that trigger |
|
|
486 | "at" the specified time, it can also be used for non-drifting |
|
|
487 | absolute timers and more complex, cron-like, setups that are not |
|
|
488 | adversely affected by time jumps (i.e. when the system clock is |
|
|
489 | changed by explicit date -s or other means such as ntpd). It is also |
|
|
490 | the most complex watcher type in EV. |
240 | |
491 | |
241 | If the $interval is zero, then the callback will be called at the |
492 | It has three distinct "modes": |
242 | time $at if that is in the future, or as soon as possible if it is |
|
|
243 | in the past. It will not automatically repeat. |
|
|
244 | |
493 | |
245 | If the $interval is nonzero, then the watcher will always be |
494 | * absolute timer ($interval = $reschedule_cb = 0) |
246 | scheduled to time out at the next "$at + N * $interval" time. |
|
|
247 | |
495 | |
248 | This can be used to schedule a callback to run at very regular |
496 | This time simply fires at the wallclock time $at and doesn't |
249 | intervals, as long as the processing time is less then the interval |
497 | repeat. It will not adjust when a time jump occurs, that is, if |
250 | (otherwise obviously events will be skipped). |
498 | it is to be run at January 1st 2011 then it will run when the |
|
|
499 | system time reaches or surpasses this time. |
251 | |
500 | |
|
|
501 | * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
502 | |
|
|
503 | In this mode the watcher will always be scheduled to time out at |
|
|
504 | the next "$at + N * $interval" time (for some integer N) and |
|
|
505 | then repeat, regardless of any time jumps. |
|
|
506 | |
|
|
507 | This can be used to create timers that do not drift with respect |
|
|
508 | to system time: |
|
|
509 | |
|
|
510 | my $hourly = EV::periodic 0, 3600, 0, sub { print "once/hour\n" }; |
|
|
511 | |
|
|
512 | That doesn't mean there will always be 3600 seconds in between |
|
|
513 | triggers, but only that the the clalback will be called when the |
|
|
514 | system time shows a full hour (UTC). |
|
|
515 | |
252 | Another way to think about it (for the mathematically inclined) is |
516 | Another way to think about it (for the mathematically inclined) |
253 | that EV::periodic will try to run the callback at the next possible |
517 | is that EV::periodic will try to run the callback in this mode |
254 | time where "$time = $at (mod $interval)", regardless of any time |
518 | at the next possible time where "$time = $at (mod $interval)", |
255 | jumps. |
519 | regardless of any time jumps. |
256 | |
520 | |
257 | This periodic timer is based on "wallclock time", that is, if the |
521 | * manual reschedule mode ($reschedule_cb = coderef) |
258 | clock changes ("ntp", "date -s" etc.), then the timer will |
522 | |
259 | nevertheless run at the specified time. This means it will never |
523 | In this mode $interval and $at are both being ignored. Instead, |
260 | drift (it might jitter, but it will not drift). |
524 | each time the periodic watcher gets scheduled, the reschedule |
|
|
525 | callback ($reschedule_cb) will be called with the watcher as |
|
|
526 | first, and the current time as second argument. |
|
|
527 | |
|
|
528 | *This callback MUST NOT stop or destroy this or any other |
|
|
529 | periodic watcher, ever, and MUST NOT call any event loop |
|
|
530 | functions or methods*. If you need to stop it, return 1e30 and |
|
|
531 | stop it afterwards. You may create and start a "EV::prepare" |
|
|
532 | watcher for this task. |
|
|
533 | |
|
|
534 | It must return the next time to trigger, based on the passed |
|
|
535 | time value (that is, the lowest time value larger than or equal |
|
|
536 | to to the second argument). It will usually be called just |
|
|
537 | before the callback will be triggered, but might be called at |
|
|
538 | other times, too. |
|
|
539 | |
|
|
540 | This can be used to create very complex timers, such as a timer |
|
|
541 | that triggers on each midnight, local time (actually 24 hours |
|
|
542 | after the last midnight, to keep the example simple. If you know |
|
|
543 | a way to do it correctly in about the same space (without |
|
|
544 | requiring elaborate modules), drop me a note :): |
|
|
545 | |
|
|
546 | my $daily = EV::periodic 0, 0, sub { |
|
|
547 | my ($w, $now) = @_; |
|
|
548 | |
|
|
549 | use Time::Local (); |
|
|
550 | my (undef, undef, undef, $d, $m, $y) = localtime $now; |
|
|
551 | 86400 + Time::Local::timelocal 0, 0, 0, $d, $m, $y |
|
|
552 | }, sub { |
|
|
553 | print "it's midnight or likely shortly after, now\n"; |
|
|
554 | }; |
261 | |
555 | |
262 | The "periodic_ns" variant doesn't start (activate) the newly created |
556 | The "periodic_ns" variant doesn't start (activate) the newly created |
263 | watcher. |
557 | watcher. |
264 | |
558 | |
265 | $w->set ($at, $interval) |
559 | $w->set ($at, $interval, $reschedule_cb) |
266 | Reconfigures the watcher, see the constructor above for details. Can |
560 | Reconfigures the watcher, see the constructor above for details. Can |
267 | be at any time. |
561 | be called at any time. |
268 | |
562 | |
|
|
563 | $w->again |
|
|
564 | Simply stops and starts the watcher again. |
|
|
565 | |
|
|
566 | $time = $w->at |
|
|
567 | Return the time that the watcher is expected to trigger next. |
|
|
568 | |
|
|
569 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
269 | $w = EV::signal $signal, $callback |
570 | $w = EV::signal $signal, $callback |
270 | $w = EV::signal_ns $signal, $callback |
571 | $w = EV::signal_ns $signal, $callback |
271 | Call the callback when $signal is received (the signal can be |
572 | Call the callback when $signal is received (the signal can be |
272 | specified by number or by name, just as with kill or %SIG). |
573 | specified by number or by name, just as with "kill" or %SIG). |
273 | |
574 | |
274 | EV will grab the signal for the process (the kernel only allows one |
575 | EV will grab the signal for the process (the kernel only allows one |
275 | component to receive a signal at a time) when you start a signal |
576 | component to receive a signal at a time) when you start a signal |
276 | watcher, and removes it again when you stop it. Perl does the same |
577 | watcher, and removes it again when you stop it. Perl does the same |
277 | when you add/remove callbacks to %SIG, so watch out. |
578 | when you add/remove callbacks to %SIG, so watch out. |
… | |
… | |
281 | The "signal_ns" variant doesn't start (activate) the newly created |
582 | The "signal_ns" variant doesn't start (activate) the newly created |
282 | watcher. |
583 | watcher. |
283 | |
584 | |
284 | $w->set ($signal) |
585 | $w->set ($signal) |
285 | Reconfigures the watcher, see the constructor above for details. Can |
586 | Reconfigures the watcher, see the constructor above for details. Can |
286 | be at any time. |
587 | be called at any time. |
287 | |
588 | |
288 | $current_signum = $w->signal |
589 | $current_signum = $w->signal |
289 | $old_signum = $w->signal ($new_signal) |
590 | $old_signum = $w->signal ($new_signal) |
290 | Returns the previously set signal (always as a number not name) and |
591 | Returns the previously set signal (always as a number not name) and |
291 | optionally set a new one. |
592 | optionally set a new one. |
292 | |
593 | |
|
|
594 | CHILD WATCHERS - watch out for process status changes |
293 | $w = EV::child $pid, $callback |
595 | $w = EV::child $pid, $trace, $callback |
294 | $w = EV::child_ns $pid, $callback |
596 | $w = EV::child_ns $pid, $trace, $callback |
|
|
597 | $w = $loop->child ($pid, $trace, $callback) |
|
|
598 | $w = $loop->child_ns ($pid, $trace, $callback) |
295 | Call the callback when a status change for pid $pid (or any pid if |
599 | Call the callback when a status change for pid $pid (or any pid if |
296 | $pid is 0) has been received. More precisely: when the process |
600 | $pid is 0) has been received (a status change happens when the |
|
|
601 | process terminates or is killed, or, when trace is true, |
|
|
602 | additionally when it is stopped or continued). More precisely: when |
297 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status |
603 | the process receives a "SIGCHLD", EV will fetch the outstanding |
298 | for all changed/zombie children and call the callback. |
604 | exit/wait status for all changed/zombie children and call the |
|
|
605 | callback. |
299 | |
606 | |
300 | You can access both status and pid by using the "rstatus" and "rpid" |
607 | It is valid (and fully supported) to install a child watcher after a |
|
|
608 | child has exited but before the event loop has started its next |
|
|
609 | iteration (for example, first you "fork", then the new child process |
|
|
610 | might exit, and only then do you install a child watcher in the |
|
|
611 | parent for the new pid). |
|
|
612 | |
|
|
613 | You can access both exit (or tracing) status and pid by using the |
301 | methods on the watcher object. |
614 | "rstatus" and "rpid" methods on the watcher object. |
302 | |
615 | |
303 | You can have as many pid watchers per pid as you want. |
616 | You can have as many pid watchers per pid as you want, they will all |
|
|
617 | be called. |
304 | |
618 | |
305 | The "child_ns" variant doesn't start (activate) the newly created |
619 | The "child_ns" variant doesn't start (activate) the newly created |
306 | watcher. |
620 | watcher. |
307 | |
621 | |
308 | $w->set ($pid) |
622 | $w->set ($pid, $trace) |
309 | Reconfigures the watcher, see the constructor above for details. Can |
623 | Reconfigures the watcher, see the constructor above for details. Can |
310 | be at any time. |
624 | be called at any time. |
311 | |
625 | |
312 | $current_pid = $w->pid |
626 | $current_pid = $w->pid |
313 | $old_pid = $w->pid ($new_pid) |
|
|
314 | Returns the previously set process id and optionally set a new one. |
627 | Returns the previously set process id and optionally set a new one. |
315 | |
628 | |
316 | $exit_status = $w->rstatus |
629 | $exit_status = $w->rstatus |
317 | Return the exit/wait status (as returned by waitpid, see the waitpid |
630 | Return the exit/wait status (as returned by waitpid, see the waitpid |
318 | entry in perlfunc). |
631 | entry in perlfunc). |
319 | |
632 | |
320 | $pid = $w->rpid |
633 | $pid = $w->rpid |
321 | Return the pid of the awaited child (useful when you have installed |
634 | Return the pid of the awaited child (useful when you have installed |
322 | a watcher for all pids). |
635 | a watcher for all pids). |
323 | |
636 | |
|
|
637 | STAT WATCHERS - did the file attributes just change? |
|
|
638 | $w = EV::stat $path, $interval, $callback |
|
|
639 | $w = EV::stat_ns $path, $interval, $callback |
|
|
640 | $w = $loop->stat ($path, $interval, $callback) |
|
|
641 | $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
642 | Call the callback when a file status change has been detected on |
|
|
643 | $path. The $path does not need to exist, changing from "path exists" |
|
|
644 | to "path does not exist" is a status change like any other. |
|
|
645 | |
|
|
646 | The $interval is a recommended polling interval for systems where |
|
|
647 | OS-supported change notifications don't exist or are not supported. |
|
|
648 | If you use 0 then an unspecified default is used (which is highly |
|
|
649 | recommended!), which is to be expected to be around five seconds |
|
|
650 | usually. |
|
|
651 | |
|
|
652 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
653 | as even with OS-supported change notifications, this can be |
|
|
654 | resource-intensive. |
|
|
655 | |
|
|
656 | The "stat_ns" variant doesn't start (activate) the newly created |
|
|
657 | watcher. |
|
|
658 | |
|
|
659 | ... = $w->stat |
|
|
660 | This call is very similar to the perl "stat" built-in: It stats |
|
|
661 | (using "lstat") the path specified in the watcher and sets perls |
|
|
662 | stat cache (as well as EV's idea of the current stat values) to the |
|
|
663 | values found. |
|
|
664 | |
|
|
665 | In scalar context, a boolean is return indicating success or failure |
|
|
666 | of the stat. In list context, the same 13-value list as with stat is |
|
|
667 | returned (except that the blksize and blocks fields are not |
|
|
668 | reliable). |
|
|
669 | |
|
|
670 | In the case of an error, errno is set to "ENOENT" (regardless of the |
|
|
671 | actual error value) and the "nlink" value is forced to zero (if the |
|
|
672 | stat was successful then nlink is guaranteed to be non-zero). |
|
|
673 | |
|
|
674 | See also the next two entries for more info. |
|
|
675 | |
|
|
676 | ... = $w->attr |
|
|
677 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
678 | the values most recently detected by EV. See the next entry for more |
|
|
679 | info. |
|
|
680 | |
|
|
681 | ... = $w->prev |
|
|
682 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
683 | the previous set of values, before the change. |
|
|
684 | |
|
|
685 | That is, when the watcher callback is invoked, "$w->prev" will be |
|
|
686 | set to the values found *before* a change was detected, while |
|
|
687 | "$w->attr" returns the values found leading to the change detection. |
|
|
688 | The difference (if any) between "prev" and "attr" is what triggered |
|
|
689 | the callback. |
|
|
690 | |
|
|
691 | If you did something to the filesystem object and do not want to |
|
|
692 | trigger yet another change, you can call "stat" to update EV's idea |
|
|
693 | of what the current attributes are. |
|
|
694 | |
|
|
695 | $w->set ($path, $interval) |
|
|
696 | Reconfigures the watcher, see the constructor above for details. Can |
|
|
697 | be called at any time. |
|
|
698 | |
|
|
699 | $current_path = $w->path |
|
|
700 | $old_path = $w->path ($new_path) |
|
|
701 | Returns the previously set path and optionally set a new one. |
|
|
702 | |
|
|
703 | $current_interval = $w->interval |
|
|
704 | $old_interval = $w->interval ($new_interval) |
|
|
705 | Returns the previously set interval and optionally set a new one. |
|
|
706 | Can be used to query the actual interval used. |
|
|
707 | |
|
|
708 | IDLE WATCHERS - when you've got nothing better to do... |
324 | $w = EV::idle $callback |
709 | $w = EV::idle $callback |
325 | $w = EV::idle_ns $callback |
710 | $w = EV::idle_ns $callback |
|
|
711 | $w = $loop->idle ($callback) |
|
|
712 | $w = $loop->idle_ns ($callback) |
326 | Call the callback when there are no pending io, timer/periodic, |
713 | Call the callback when there are no other pending watchers of the |
327 | signal or child events, i.e. when the process is idle. |
714 | same or higher priority (excluding check, prepare and other idle |
|
|
715 | watchers of the same or lower priority, of course). They are called |
|
|
716 | idle watchers because when the watcher is the highest priority |
|
|
717 | pending event in the process, the process is considered to be idle |
|
|
718 | at that priority. |
|
|
719 | |
|
|
720 | If you want a watcher that is only ever called when *no* other |
|
|
721 | events are outstanding you have to set the priority to "EV::MINPRI". |
328 | |
722 | |
329 | The process will not block as long as any idle watchers are active, |
723 | The process will not block as long as any idle watchers are active, |
330 | and they will be called repeatedly until stopped. |
724 | and they will be called repeatedly until stopped. |
331 | |
725 | |
|
|
726 | For example, if you have idle watchers at priority 0 and 1, and an |
|
|
727 | I/O watcher at priority 0, then the idle watcher at priority 1 and |
|
|
728 | the I/O watcher will always run when ready. Only when the idle |
|
|
729 | watcher at priority 1 is stopped and the I/O watcher at priority 0 |
|
|
730 | is not pending with the 0-priority idle watcher be invoked. |
|
|
731 | |
332 | The "idle_ns" variant doesn't start (activate) the newly created |
732 | The "idle_ns" variant doesn't start (activate) the newly created |
333 | watcher. |
733 | watcher. |
334 | |
734 | |
|
|
735 | PREPARE WATCHERS - customise your event loop! |
335 | $w = EV::prepare $callback |
736 | $w = EV::prepare $callback |
336 | $w = EV::prepare_ns $callback |
737 | $w = EV::prepare_ns $callback |
|
|
738 | $w = $loop->prepare ($callback) |
|
|
739 | $w = $loop->prepare_ns ($callback) |
337 | Call the callback just before the process would block. You can still |
740 | Call the callback just before the process would block. You can still |
338 | create/modify any watchers at this point. |
741 | create/modify any watchers at this point. |
339 | |
742 | |
340 | See the EV::check watcher, below, for explanations and an example. |
743 | See the EV::check watcher, below, for explanations and an example. |
341 | |
744 | |
342 | The "prepare_ns" variant doesn't start (activate) the newly created |
745 | The "prepare_ns" variant doesn't start (activate) the newly created |
343 | watcher. |
746 | watcher. |
344 | |
747 | |
|
|
748 | CHECK WATCHERS - customise your event loop even more! |
345 | $w = EV::check $callback |
749 | $w = EV::check $callback |
346 | $w = EV::check_ns $callback |
750 | $w = EV::check_ns $callback |
|
|
751 | $w = $loop->check ($callback) |
|
|
752 | $w = $loop->check_ns ($callback) |
347 | Call the callback just after the process wakes up again (after it |
753 | Call the callback just after the process wakes up again (after it |
348 | has gathered events), but before any other callbacks have been |
754 | has gathered events), but before any other callbacks have been |
349 | invoked. |
755 | invoked. |
350 | |
756 | |
351 | This is used to integrate other event-based software into the EV |
757 | This is used to integrate other event-based software into the EV |
… | |
… | |
360 | # do nothing unless active |
766 | # do nothing unless active |
361 | $dispatcher->{_event_queue_h} |
767 | $dispatcher->{_event_queue_h} |
362 | or return; |
768 | or return; |
363 | |
769 | |
364 | # make the dispatcher handle any outstanding stuff |
770 | # make the dispatcher handle any outstanding stuff |
|
|
771 | ... not shown |
365 | |
772 | |
366 | # create an IO watcher for each and every socket |
773 | # create an I/O watcher for each and every socket |
367 | @snmp_watcher = ( |
774 | @snmp_watcher = ( |
368 | (map { EV::io $_, EV::READ, sub { } } |
775 | (map { EV::io $_, EV::READ, sub { } } |
369 | keys %{ $dispatcher->{_descriptors} }), |
776 | keys %{ $dispatcher->{_descriptors} }), |
|
|
777 | |
|
|
778 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
|
|
779 | ? $event->[Net::SNMP::Dispatcher::_TIME] - EV::now : 0), |
|
|
780 | 0, sub { }, |
370 | ); |
781 | ); |
371 | |
|
|
372 | # if there are any timeouts, also create a timer |
|
|
373 | push @snmp_watcher, EV::timer $event->[Net::SNMP::Dispatcher::_TIME] - EV::now, 0, sub { } |
|
|
374 | if $event->[Net::SNMP::Dispatcher::_ACTIVE]; |
|
|
375 | }; |
782 | }; |
376 | |
783 | |
377 | The callbacks are irrelevant, the only purpose of those watchers is |
784 | The callbacks are irrelevant (and are not even being called), the |
378 | to wake up the process as soon as one of those events occurs (socket |
785 | only purpose of those watchers is to wake up the process as soon as |
379 | readable, or timer timed out). The corresponding EV::check watcher |
786 | one of those events occurs (socket readable, or timer timed out). |
380 | will then clean up: |
787 | The corresponding EV::check watcher will then clean up: |
381 | |
788 | |
382 | our $snmp_check = EV::check sub { |
789 | our $snmp_check = EV::check sub { |
383 | # destroy all watchers |
790 | # destroy all watchers |
384 | @snmp_watcher = (); |
791 | @snmp_watcher = (); |
385 | |
792 | |
386 | # make the dispatcher handle any new stuff |
793 | # make the dispatcher handle any new stuff |
|
|
794 | ... not shown |
387 | }; |
795 | }; |
388 | |
796 | |
389 | The callbacks of the created watchers will not be called as the |
797 | The callbacks of the created watchers will not be called as the |
390 | watchers are destroyed before this cna happen (remember EV::check |
798 | watchers are destroyed before this can happen (remember EV::check |
391 | gets called first). |
799 | gets called first). |
392 | |
800 | |
393 | The "check_ns" variant doesn't start (activate) the newly created |
801 | The "check_ns" variant doesn't start (activate) the newly created |
394 | watcher. |
802 | watcher. |
395 | |
803 | |
|
|
804 | FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
805 | Fork watchers are called when a "fork ()" was detected. The invocation |
|
|
806 | is done before the event loop blocks next and before "check" watchers |
|
|
807 | are being called, and only in the child after the fork. |
|
|
808 | |
|
|
809 | $w = EV::fork $callback |
|
|
810 | $w = EV::fork_ns $callback |
|
|
811 | $w = $loop->fork ($callback) |
|
|
812 | $w = $loop->fork_ns ($callback) |
|
|
813 | Call the callback before the event loop is resumed in the child |
|
|
814 | process after a fork. |
|
|
815 | |
|
|
816 | The "fork_ns" variant doesn't start (activate) the newly created |
|
|
817 | watcher. |
|
|
818 | |
|
|
819 | EMBED WATCHERS - when one backend isn't enough... |
|
|
820 | This is a rather advanced watcher type that lets you embed one event |
|
|
821 | loop into another (currently only IO events are supported in the |
|
|
822 | embedded loop, other types of watchers might be handled in a delayed or |
|
|
823 | incorrect fashion and must not be used). |
|
|
824 | |
|
|
825 | See the libev documentation at |
|
|
826 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code |
|
|
827 | _when_one_backend_> (locally installed as EV::libev) for more details. |
|
|
828 | |
|
|
829 | In short, this watcher is most useful on BSD systems without working |
|
|
830 | kqueue to still be able to handle a large number of sockets: |
|
|
831 | |
|
|
832 | my $socket_loop; |
|
|
833 | |
|
|
834 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
835 | if ( |
|
|
836 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
837 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
838 | ) { |
|
|
839 | # use kqueue for sockets |
|
|
840 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
841 | } |
|
|
842 | |
|
|
843 | # use the default loop otherwise |
|
|
844 | $socket_loop ||= EV::default_loop; |
|
|
845 | |
|
|
846 | $w = EV::embed $otherloop[, $callback] |
|
|
847 | $w = EV::embed_ns $otherloop[, $callback] |
|
|
848 | $w = $loop->embed ($otherloop[, $callback]) |
|
|
849 | $w = $loop->embed_ns ($otherloop[, $callback]) |
|
|
850 | Call the callback when the embedded event loop ($otherloop) has any |
|
|
851 | I/O activity. The $callback is optional: if it is missing, then the |
|
|
852 | embedded event loop will be managed automatically (which is |
|
|
853 | recommended), otherwise you have to invoke "sweep" yourself. |
|
|
854 | |
|
|
855 | The "embed_ns" variant doesn't start (activate) the newly created |
|
|
856 | watcher. |
|
|
857 | |
|
|
858 | ASYNC WATCHERS - how to wake up another event loop |
|
|
859 | Async watchers are provided by EV, but have little use in perl directly, |
|
|
860 | as perl neither supports threads running in parallel nor direct access |
|
|
861 | to signal handlers or other contexts where they could be of value. |
|
|
862 | |
|
|
863 | It is, however, possible to use them from the XS level. |
|
|
864 | |
|
|
865 | Please see the libev documentation for further details. |
|
|
866 | |
|
|
867 | $w = EV::async $callback |
|
|
868 | $w = EV::async_ns $callback |
|
|
869 | $w->send |
|
|
870 | $bool = $w->async_pending |
|
|
871 | |
|
|
872 | PERL SIGNALS |
|
|
873 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
|
|
874 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
875 | handled when Perl runs, which means your signal handler might be invoked |
|
|
876 | only the next time an event callback is invoked. |
|
|
877 | |
|
|
878 | The solution is to use EV signal watchers (see "EV::signal"), which will |
|
|
879 | ensure proper operations with regards to other event watchers. |
|
|
880 | |
|
|
881 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
882 | to be called on every event loop iteration by installing a "EV::check" |
|
|
883 | watcher: |
|
|
884 | |
|
|
885 | my $async_check = EV::check sub { }; |
|
|
886 | |
|
|
887 | This ensures that perl gets into control for a short time to handle any |
|
|
888 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
889 | |
396 | THREADS |
890 | ITHREADS |
397 | Threads are not supported by this in any way. Perl pseudo-threads is |
891 | Ithreads are not supported by this module in any way. Perl |
398 | evil stuff and must die. |
892 | pseudo-threads is evil stuff and must die. Real threads as provided by |
|
|
893 | Coro are fully supported (and enhanced support is available via |
|
|
894 | Coro::EV). |
|
|
895 | |
|
|
896 | FORK |
|
|
897 | Most of the "improved" event delivering mechanisms of modern operating |
|
|
898 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
|
|
899 | not supported and usually destructive). Libev makes it possible to work |
|
|
900 | around this by having a function that recreates the kernel state after |
|
|
901 | fork in the child. |
|
|
902 | |
|
|
903 | On non-win32 platforms, this module requires the pthread_atfork |
|
|
904 | functionality to do this automatically for you. This function is quite |
|
|
905 | buggy on most BSDs, though, so YMMV. The overhead for this is quite |
|
|
906 | negligible, because everything the function currently does is set a flag |
|
|
907 | that is checked only when the event loop gets used the next time, so |
|
|
908 | when you do fork but not use EV, the overhead is minimal. |
|
|
909 | |
|
|
910 | On win32, there is no notion of fork so all this doesn't apply, of |
|
|
911 | course. |
399 | |
912 | |
400 | SEE ALSO |
913 | SEE ALSO |
401 | L<EV::DNS>, L<EV::AnyEvent>. |
914 | EV::ADNS (asynchronous DNS), Glib::EV (makes Glib/Gtk2 use EV as event |
|
|
915 | loop), EV::Glib (embed Glib into EV), Coro::EV (efficient coroutines |
|
|
916 | with EV), Net::SNMP::EV (asynchronous SNMP), AnyEvent for event-loop |
|
|
917 | agnostic and portable event driven programming. |
402 | |
918 | |
403 | AUTHOR |
919 | AUTHOR |
404 | Marc Lehmann <schmorp@schmorp.de> |
920 | Marc Lehmann <schmorp@schmorp.de> |
405 | http://home.schmorp.de/ |
921 | http://home.schmorp.de/ |
406 | |
922 | |