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, 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 |
44 | # STAT CHANGES |
38 | |
45 | my $w = EV::stat "/etc/passwd", 10, sub { |
39 | my $w = EV::child 666, sub { |
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40 | my ($w, $revents) = @_; |
46 | my ($w, $revents) = @_; |
41 | my $status = $w->rstatus; |
47 | warn $w->path, " has changed somehow.\n"; |
42 | }; |
48 | }; |
43 | |
49 | |
44 | # MAINLOOP |
50 | # MAINLOOP |
45 | EV::loop; # loop until EV::unloop is called or all watchers stop |
51 | EV::loop; # loop until EV::unloop is called or all watchers stop |
46 | 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 |
47 | 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 |
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54 | |
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55 | BEFORE YOU START USING THIS MODULE |
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56 | If you only need timer, I/O, signal, child and idle watchers and not the |
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57 | advanced functionality of this module, consider using AnyEvent instead, |
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58 | specifically the simplified API described in AE. |
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59 | |
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60 | When used with EV as backend, the AE API is as fast as the native EV |
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61 | API, but your programs/modules will still run with many other event |
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62 | loops. |
48 | |
63 | |
49 | DESCRIPTION |
64 | DESCRIPTION |
50 | This module provides an interface to libev |
65 | This module provides an interface to libev |
51 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
66 | (<http://software.schmorp.de/pkg/libev.html>). While the documentation |
52 | below is comprehensive, one might also consult the documentation of |
67 | below is comprehensive, one might also consult the documentation of |
53 | libev itself (<http://cvs.schmorp.de/libev/ev.html>) for more subtle |
68 | libev itself (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod> or |
54 | details on watcher semantics or some discussion on the available |
69 | perldoc EV::libev) for more subtle details on watcher semantics or some |
55 | backends, or how to force a specific backend with "LIBEV_FLAGS". |
70 | discussion on the available backends, or how to force a specific backend |
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71 | with "LIBEV_FLAGS", or just about in any case because it has much more |
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72 | detailed information. |
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73 | |
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74 | This module is very fast and scalable. It is actually so fast that you |
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75 | can use it through the AnyEvent module, stay portable to other event |
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76 | loops (if you don't rely on any watcher types not available through it) |
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77 | and still be faster than with any other event loop currently supported |
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78 | in Perl. |
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79 | |
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80 | PORTING FROM EV 3.X to 4.X |
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81 | EV version 4 introduces a number of incompatible changes summarised |
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82 | here. According to the depreciation strategy used by libev, there is a |
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83 | compatibility layer in place so programs should continue to run |
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84 | unchanged (the XS interface lacks this layer, so programs using that one |
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85 | need to be updated). |
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86 | |
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87 | This compatibility layer will be switched off in some future release. |
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88 | |
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89 | All changes relevant to Perl are renames of symbols, functions and |
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90 | methods: |
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91 | |
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92 | EV::loop => EV::run |
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93 | EV::LOOP_NONBLOCK => EV::RUN_NOWAIT |
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94 | EV::LOOP_ONESHOT => EV::RUN_ONCE |
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95 | |
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96 | EV::unloop => EV::break |
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97 | EV::UNLOOP_CANCEL => EV::BREAK_CANCEL |
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98 | EV::UNLOOP_ONE => EV::BREAK_ONE |
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99 | EV::UNLOOP_ALL => EV::BREAK_ALL |
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100 | |
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101 | EV::TIMEOUT => EV::TIMER |
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102 | |
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103 | EV::loop_count => EV::iteration |
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104 | EV::loop_depth => EV::depth |
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105 | EV::loop_verify => EV::verify |
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106 | |
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107 | The loop object methods corresponding to the functions above have been |
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108 | similarly renamed. |
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109 | |
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110 | MODULE EXPORTS |
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111 | This module does not export any symbols. |
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112 | |
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113 | EVENT LOOPS |
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114 | EV supports multiple event loops: There is a single "default event loop" |
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115 | that can handle everything including signals and child watchers, and any |
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116 | number of "dynamic event loops" that can use different backends (with |
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117 | various limitations), but no child and signal watchers. |
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118 | |
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119 | You do not have to do anything to create the default event loop: When |
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120 | the module is loaded a suitable backend is selected on the premise of |
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121 | selecting a working backend (which for example rules out kqueue on most |
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122 | BSDs). Modules should, unless they have "special needs" always use the |
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123 | default loop as this is fastest (perl-wise), best supported by other |
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124 | modules (e.g. AnyEvent or Coro) and most portable event loop. |
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125 | |
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126 | For specific programs you can create additional event loops dynamically. |
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127 | |
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128 | If you want to take advantage of kqueue (which often works properly for |
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129 | sockets only) even though the default loop doesn't enable it, you can |
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130 | *embed* a kqueue loop into the default loop: running the default loop |
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131 | will then also service the kqueue loop to some extent. See the example |
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132 | in the section about embed watchers for an example on how to achieve |
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133 | that. |
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134 | |
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135 | $loop = new EV::Loop [$flags] |
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136 | Create a new event loop as per the specified flags. Please refer to |
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137 | the "ev_loop_new ()" function description in the libev documentation |
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138 | (<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#GLOBAL_FUNCTI |
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139 | ONS>, or locally-installed as EV::libev manpage) for more info. |
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140 | |
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141 | The loop will automatically be destroyed when it is no longer |
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142 | referenced by any watcher and the loop object goes out of scope. |
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143 | |
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144 | If you are not embedding the loop, then Using "EV::FLAG_FORKCHECK" |
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145 | is recommended, as only the default event loop is protected by this |
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146 | module. If you *are* embedding this loop in the default loop, this |
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147 | is not necessary, as "EV::embed" automatically does the right thing |
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148 | on fork. |
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149 | |
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150 | $loop->loop_fork |
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151 | Must be called after a fork in the child, before entering or |
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152 | continuing the event loop. An alternative is to use |
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153 | "EV::FLAG_FORKCHECK" which calls this function automatically, at |
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154 | some performance loss (refer to the libev documentation). |
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155 | |
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156 | $loop->loop_verify |
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157 | Calls "ev_verify" to make internal consistency checks (for debugging |
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158 | libev) and abort the program if any data structures were found to be |
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159 | corrupted. |
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160 | |
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161 | $loop = EV::default_loop [$flags] |
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162 | Return the default loop (which is a singleton object). Since this |
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163 | module already creates the default loop with default flags, |
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164 | specifying flags here will not have any effect unless you destroy |
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165 | the default loop first, which isn't supported. So in short: don't do |
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166 | it, and if you break it, you get to keep the pieces. |
56 | |
167 | |
57 | BASIC INTERFACE |
168 | BASIC INTERFACE |
58 | $EV::DIED |
169 | $EV::DIED |
59 | Must contain a reference to a function that is called when a |
170 | Must contain a reference to a function that is called when a |
60 | callback throws an exception (with $@ containing thr error). The |
171 | callback throws an exception (with $@ containing the error). The |
61 | default prints an informative message and continues. |
172 | default prints an informative message and continues. |
62 | |
173 | |
63 | If this callback throws an exception it will be silently ignored. |
174 | If this callback throws an exception it will be silently ignored. |
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175 | |
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176 | $flags = EV::supported_backends |
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177 | $flags = EV::recommended_backends |
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178 | $flags = EV::embeddable_backends |
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179 | Returns the set (see "EV::BACKEND_*" flags) of backends supported by |
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180 | this instance of EV, the set of recommended backends (supposed to be |
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181 | good) for this platform and the set of embeddable backends (see |
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182 | EMBED WATCHERS). |
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183 | |
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184 | EV::sleep $seconds |
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185 | Block the process for the given number of (fractional) seconds. |
64 | |
186 | |
65 | $time = EV::time |
187 | $time = EV::time |
66 | Returns the current time in (fractional) seconds since the epoch. |
188 | Returns the current time in (fractional) seconds since the epoch. |
67 | |
189 | |
68 | $time = EV::now |
190 | $time = EV::now |
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191 | $time = $loop->now |
69 | Returns the time the last event loop iteration has been started. |
192 | Returns the time the last event loop iteration has been started. |
70 | This is the time that (relative) timers are based on, and refering |
193 | This is the time that (relative) timers are based on, and referring |
71 | to it is usually faster then calling EV::time. |
194 | to it is usually faster then calling EV::time. |
72 | |
195 | |
73 | $method = EV::method |
196 | EV::now_update |
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197 | $loop->now_update |
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198 | Establishes the current time by querying the kernel, updating the |
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199 | time returned by "EV::now" in the progress. This is a costly |
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200 | operation and is usually done automatically within "EV::loop". |
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201 | |
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202 | This function is rarely useful, but when some event callback runs |
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203 | for a very long time without entering the event loop, updating |
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204 | libev's idea of the current time is a good idea. |
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205 | |
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206 | EV::suspend |
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207 | $loop->suspend |
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208 | EV::resume |
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209 | $loop->resume |
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210 | These two functions suspend and resume a loop, for use when the loop |
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211 | is not used for a while and timeouts should not be processed. |
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212 | |
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213 | A typical use case would be an interactive program such as a game: |
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214 | When the user presses "^Z" to suspend the game and resumes it an |
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215 | hour later it would be best to handle timeouts as if no time had |
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216 | actually passed while the program was suspended. This can be |
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217 | achieved by calling "suspend" in your "SIGTSTP" handler, sending |
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218 | yourself a "SIGSTOP" and calling "resume" directly afterwards to |
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219 | resume timer processing. |
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220 | |
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221 | Effectively, all "timer" watchers will be delayed by the time spend |
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222 | between "suspend" and "resume", and all "periodic" watchers will be |
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223 | rescheduled (that is, they will lose any events that would have |
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224 | occured while suspended). |
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225 | |
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226 | After calling "suspend" you must not call *any* function on the |
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227 | given loop other than "resume", and you must not call "resume" |
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228 | without a previous call to "suspend". |
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229 | |
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230 | Calling "suspend"/"resume" has the side effect of updating the event |
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231 | loop time (see "now_update"). |
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232 | |
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233 | $backend = EV::backend |
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234 | $backend = $loop->backend |
74 | Returns an integer describing the backend used by libev |
235 | Returns an integer describing the backend used by libev |
75 | (EV::METHOD_SELECT or EV::METHOD_EPOLL). |
236 | (EV::BACKEND_SELECT or EV::BACKEND_EPOLL). |
76 | |
237 | |
77 | EV::loop [$flags] |
238 | EV::loop [$flags] |
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239 | $loop->loop ([$flags]) |
78 | Begin checking for events and calling callbacks. It returns when a |
240 | Begin checking for events and calling callbacks. It returns when a |
79 | callback calls EV::unloop. |
241 | callback calls EV::unloop. |
80 | |
242 | |
81 | The $flags argument can be one of the following: |
243 | The $flags argument can be one of the following: |
82 | |
244 | |
83 | 0 as above |
245 | 0 as above |
84 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
246 | EV::LOOP_ONESHOT block at most once (wait, but do not loop) |
85 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
247 | EV::LOOP_NONBLOCK do not block at all (fetch/handle events but do not wait) |
86 | |
248 | |
87 | EV::unloop [$how] |
249 | EV::unloop [$how] |
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250 | $loop->unloop ([$how]) |
88 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
251 | When called with no arguments or an argument of EV::UNLOOP_ONE, |
89 | makes the innermost call to EV::loop return. |
252 | makes the innermost call to EV::loop return. |
90 | |
253 | |
91 | When called with an argument of EV::UNLOOP_ALL, all calls to |
254 | When called with an argument of EV::UNLOOP_ALL, all calls to |
92 | EV::loop will return as fast as possible. |
255 | EV::loop will return as fast as possible. |
93 | |
256 | |
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257 | $count = EV::loop_count |
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258 | $count = $loop->loop_count |
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259 | Return the number of times the event loop has polled for new events. |
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260 | Sometimes useful as a generation counter. |
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261 | |
94 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
262 | EV::once $fh_or_undef, $events, $timeout, $cb->($revents) |
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263 | $loop->once ($fh_or_undef, $events, $timeout, $cb->($revents)) |
95 | This function rolls together an I/O and a timer watcher for a single |
264 | This function rolls together an I/O and a timer watcher for a single |
96 | one-shot event without the need for managing a watcher object. |
265 | one-shot event without the need for managing a watcher object. |
97 | |
266 | |
98 | If $fh_or_undef is a filehandle or file descriptor, then $events |
267 | If $fh_or_undef is a filehandle or file descriptor, then $events |
99 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
268 | must be a bitset containing either "EV::READ", "EV::WRITE" or |
… | |
… | |
104 | If timeout is "undef" or negative, then there will be no timeout. |
273 | If timeout is "undef" or negative, then there will be no timeout. |
105 | Otherwise a EV::timer with this value will be started. |
274 | Otherwise a EV::timer with this value will be started. |
106 | |
275 | |
107 | When an error occurs or either the timeout or I/O watcher triggers, |
276 | When an error occurs or either the timeout or I/O watcher triggers, |
108 | then the callback will be called with the received event set (in |
277 | then the callback will be called with the received event set (in |
109 | general you can expect it to be a combination of "EV:ERROR", |
278 | general you can expect it to be a combination of "EV::ERROR", |
110 | "EV::READ", "EV::WRITE" and "EV::TIMEOUT"). |
279 | "EV::READ", "EV::WRITE" and "EV::TIMER"). |
111 | |
280 | |
112 | EV::once doesn't return anything: the watchers stay active till |
281 | EV::once doesn't return anything: the watchers stay active till |
113 | either of them triggers, then they will be stopped and freed, and |
282 | either of them triggers, then they will be stopped and freed, and |
114 | the callback invoked. |
283 | the callback invoked. |
115 | |
284 | |
116 | WATCHER |
285 | EV::feed_fd_event ($fd, $revents) |
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286 | $loop->feed_fd_event ($fd, $revents) |
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287 | Feed an event on a file descriptor into EV. EV will react to this |
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288 | call as if the readyness notifications specified by $revents (a |
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289 | combination of "EV::READ" and "EV::WRITE") happened on the file |
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290 | descriptor $fd. |
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291 | |
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292 | EV::feed_signal_event ($signal) |
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293 | Feed a signal event into EV. EV will react to this call as if the |
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294 | signal specified by $signal had occured. |
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295 | |
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296 | EV::set_io_collect_interval $time |
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297 | $loop->set_io_collect_interval ($time) |
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298 | EV::set_timeout_collect_interval $time |
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299 | $loop->set_timeout_collect_interval ($time) |
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300 | These advanced functions set the minimum block interval when polling |
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301 | for I/O events and the minimum wait interval for timer events. See |
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302 | the libev documentation at |
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303 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#FUNCTIONS_CONT |
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304 | ROLLING_THE_EVENT_LOOP> (locally installed as EV::libev) for a more |
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305 | detailed discussion. |
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306 | |
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307 | $count = EV::pending_count |
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308 | $count = $loop->pending_count |
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309 | Returns the number of currently pending watchers. |
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310 | |
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311 | EV::invoke_pending |
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312 | $loop->invoke_pending |
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313 | Invoke all currently pending watchers. |
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314 | |
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315 | WATCHER OBJECTS |
117 | A watcher is an object that gets created to record your interest in some |
316 | A watcher is an object that gets created to record your interest in some |
118 | event. For instance, if you want to wait for STDIN to become readable, |
317 | event. For instance, if you want to wait for STDIN to become readable, |
119 | you would create an EV::io watcher for that: |
318 | you would create an EV::io watcher for that: |
120 | |
319 | |
121 | my $watcher = EV::io *STDIN, EV::READ, sub { |
320 | my $watcher = EV::io *STDIN, EV::READ, sub { |
122 | my ($watcher, $revents) = @_; |
321 | my ($watcher, $revents) = @_; |
123 | warn "yeah, STDIN should not be readable without blocking!\n" |
322 | warn "yeah, STDIN should now be readable without blocking!\n" |
124 | }; |
323 | }; |
125 | |
324 | |
126 | All watchers can be active (waiting for events) or inactive (paused). |
325 | All watchers can be active (waiting for events) or inactive (paused). |
127 | Only active watchers will have their callbacks invoked. All callbacks |
326 | Only active watchers will have their callbacks invoked. All callbacks |
128 | will be called with at least two arguments: the watcher and a bitmask of |
327 | will be called with at least two arguments: the watcher and a bitmask of |
129 | received events. |
328 | received events. |
130 | |
329 | |
131 | Each watcher type has its associated bit in revents, so you can use the |
330 | Each watcher type has its associated bit in revents, so you can use the |
132 | same callback for multiple watchers. The event mask is named after the |
331 | same callback for multiple watchers. The event mask is named after the |
133 | type, i..e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
332 | type, i.e. EV::child sets EV::CHILD, EV::prepare sets EV::PREPARE, |
134 | EV::periodic sets EV::PERIODIC and so on, with the exception of IO |
333 | EV::periodic sets EV::PERIODIC and so on, with the exception of I/O |
135 | events (which can set both EV::READ and EV::WRITE bits), and EV::timer |
334 | events (which can set both EV::READ and EV::WRITE bits). |
136 | (which uses EV::TIMEOUT). |
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137 | |
335 | |
138 | In the rare case where one wants to create a watcher but not start it at |
336 | In the rare case where one wants to create a watcher but not start it at |
139 | the same time, each constructor has a variant with a trailing "_ns" in |
337 | the same time, each constructor has a variant with a trailing "_ns" in |
140 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
338 | its name, e.g. EV::io has a non-starting variant EV::io_ns and so on. |
141 | |
339 | |
… | |
… | |
145 | |
343 | |
146 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
344 | Also, all methods changing some aspect of a watcher (->set, ->priority, |
147 | ->fh and so on) automatically stop and start it again if it is active, |
345 | ->fh and so on) automatically stop and start it again if it is active, |
148 | which means pending events get lost. |
346 | which means pending events get lost. |
149 | |
347 | |
150 | WATCHER TYPES |
348 | COMMON WATCHER METHODS |
151 | Now lets move to the existing watcher types and asociated methods. |
349 | This section lists methods common to all watchers. |
152 | |
|
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153 | The following methods are available for all watchers. Then followes a |
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154 | description of each watcher constructor (EV::io, EV::timer, |
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155 | EV::periodic, EV::signal, EV::child, EV::idle, EV::prepare and |
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156 | EV::check), followed by any type-specific methods (if any). |
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157 | |
350 | |
158 | $w->start |
351 | $w->start |
159 | Starts a watcher if it isn't active already. Does nothing to an |
352 | Starts a watcher if it isn't active already. Does nothing to an |
160 | already active watcher. By default, all watchers start out in the |
353 | already active watcher. By default, all watchers start out in the |
161 | active state (see the description of the "_ns" variants if you need |
354 | active state (see the description of the "_ns" variants if you need |
162 | stopped watchers). |
355 | stopped watchers). |
163 | |
356 | |
164 | $w->stop |
357 | $w->stop |
165 | Stop a watcher if it is active. Also clear any pending events |
358 | Stop a watcher if it is active. Also clear any pending events |
166 | (events that have been received but that didn't yet result in a |
359 | (events that have been received but that didn't yet result in a |
167 | callback invocation), regardless of wether the watcher was active or |
360 | callback invocation), regardless of whether the watcher was active |
168 | not. |
361 | or not. |
169 | |
362 | |
170 | $bool = $w->is_active |
363 | $bool = $w->is_active |
171 | Returns true if the watcher is active, false otherwise. |
364 | Returns true if the watcher is active, false otherwise. |
172 | |
365 | |
173 | $current_data = $w->data |
366 | $current_data = $w->data |
… | |
… | |
196 | The default priority of any newly-created watcher is 0. |
389 | The default priority of any newly-created watcher is 0. |
197 | |
390 | |
198 | Note that the priority semantics have not yet been fleshed out and |
391 | Note that the priority semantics have not yet been fleshed out and |
199 | are subject to almost certain change. |
392 | are subject to almost certain change. |
200 | |
393 | |
201 | $w->trigger ($revents) |
394 | $w->invoke ($revents) |
202 | Call the callback *now* with the given event mask. |
395 | Call the callback *now* with the given event mask. |
|
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396 | |
|
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397 | $w->feed_event ($revents) |
|
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398 | Feed some events on this watcher into EV. EV will react to this call |
|
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399 | as if the watcher had received the given $revents mask. |
|
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400 | |
|
|
401 | $revents = $w->clear_pending |
|
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402 | If the watcher is pending, this function clears its pending status |
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|
403 | and returns its $revents bitset (as if its callback was invoked). If |
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404 | the watcher isn't pending it does nothing and returns 0. |
203 | |
405 | |
204 | $previous_state = $w->keepalive ($bool) |
406 | $previous_state = $w->keepalive ($bool) |
205 | Normally, "EV::loop" will return when there are no active watchers |
407 | Normally, "EV::loop" will return when there are no active watchers |
206 | (which is a "deadlock" because no progress can be made anymore). |
408 | (which is a "deadlock" because no progress can be made anymore). |
207 | This is convinient because it allows you to start your watchers (and |
409 | This is convenient because it allows you to start your watchers (and |
208 | your jobs), call "EV::loop" once and when it returns you know that |
410 | your jobs), call "EV::loop" once and when it returns you know that |
209 | all your jobs are finished (or they forgot to register some watchers |
411 | all your jobs are finished (or they forgot to register some watchers |
210 | for their task :). |
412 | for their task :). |
211 | |
413 | |
212 | Sometimes, however, this gets in your way, for example when you the |
414 | Sometimes, however, this gets in your way, for example when the |
213 | module that calls "EV::loop" (usually the main program) is not the |
415 | module that calls "EV::loop" (usually the main program) is not the |
214 | same module as a long-living watcher (for example a DNS client |
416 | same module as a long-living watcher (for example a DNS client |
215 | module written by somebody else even). Then you might want any |
417 | module written by somebody else even). Then you might want any |
216 | outstanding requests to be handled, but you would not want to keep |
418 | outstanding requests to be handled, but you would not want to keep |
217 | "EV::loop" from returning just because you happen to have this |
419 | "EV::loop" from returning just because you happen to have this |
… | |
… | |
219 | |
421 | |
220 | In this case you can clear the keepalive status, which means that |
422 | In this case you can clear the keepalive status, which means that |
221 | even though your watcher is active, it won't keep "EV::loop" from |
423 | even though your watcher is active, it won't keep "EV::loop" from |
222 | returning. |
424 | returning. |
223 | |
425 | |
224 | The initial value for keepalive is true (enabled), and you cna |
426 | The initial value for keepalive is true (enabled), and you can |
225 | change it any time. |
427 | change it any time. |
226 | |
428 | |
227 | Example: Register an IO watcher for some UDP socket but do not keep |
429 | Example: Register an I/O watcher for some UDP socket but do not keep |
228 | the event loop from running just because of that watcher. |
430 | the event loop from running just because of that watcher. |
229 | |
431 | |
230 | my $udp_socket = ... |
432 | my $udp_socket = ... |
231 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
433 | my $udp_watcher = EV::io $udp_socket, EV::READ, sub { ... }; |
232 | $udp_watcher->keepalive (0); |
434 | $udp_watcher->keepalive (0); |
233 | |
435 | |
|
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436 | $loop = $w->loop |
|
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437 | Return the loop that this watcher is attached to. |
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438 | |
|
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439 | WATCHER TYPES |
|
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440 | Each of the following subsections describes a single watcher type. |
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441 | |
|
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442 | I/O WATCHERS - is this file descriptor readable or writable? |
234 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
443 | $w = EV::io $fileno_or_fh, $eventmask, $callback |
235 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
444 | $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
|
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445 | $w = $loop->io ($fileno_or_fh, $eventmask, $callback) |
|
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446 | $w = $loop->io_ns ($fileno_or_fh, $eventmask, $callback) |
236 | As long as the returned watcher object is alive, call the $callback |
447 | As long as the returned watcher object is alive, call the $callback |
237 | when the events specified in $eventmask. |
448 | when at least one of events specified in $eventmask occurs. |
238 | |
449 | |
239 | 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: |
240 | |
451 | |
241 | EV::READ wait until read() wouldn't block anymore |
452 | EV::READ wait until read() wouldn't block anymore |
242 | EV::WRITE wait until write() wouldn't block anymore |
453 | EV::WRITE wait until write() wouldn't block anymore |
… | |
… | |
254 | |
465 | |
255 | $current_eventmask = $w->events |
466 | $current_eventmask = $w->events |
256 | $old_eventmask = $w->events ($new_eventmask) |
467 | $old_eventmask = $w->events ($new_eventmask) |
257 | Returns the previously set event mask and optionally set a new one. |
468 | Returns the previously set event mask and optionally set a new one. |
258 | |
469 | |
|
|
470 | TIMER WATCHERS - relative and optionally repeating timeouts |
259 | $w = EV::timer $after, $repeat, $callback |
471 | $w = EV::timer $after, $repeat, $callback |
260 | $w = EV::timer_ns $after, $repeat, $callback |
472 | $w = EV::timer_ns $after, $repeat, $callback |
|
|
473 | $w = $loop->timer ($after, $repeat, $callback) |
|
|
474 | $w = $loop->timer_ns ($after, $repeat, $callback) |
261 | Calls the callback after $after seconds (which may be fractional). |
475 | Calls the callback after $after seconds (which may be fractional). |
262 | If $repeat is non-zero, the timer will be restarted (with the |
476 | If $repeat is non-zero, the timer will be restarted (with the |
263 | $repeat value as $after) after the callback returns. |
477 | $repeat value as $after) after the callback returns. |
264 | |
478 | |
265 | This means that the callback would be called roughly after $after |
479 | This means that the callback would be called roughly after $after |
… | |
… | |
277 | The "timer_ns" variant doesn't start (activate) the newly created |
491 | The "timer_ns" variant doesn't start (activate) the newly created |
278 | watcher. |
492 | watcher. |
279 | |
493 | |
280 | $w->set ($after, $repeat) |
494 | $w->set ($after, $repeat) |
281 | Reconfigures the watcher, see the constructor above for details. Can |
495 | Reconfigures the watcher, see the constructor above for details. Can |
282 | be at any time. |
496 | be called at any time. |
283 | |
497 | |
284 | $w->again |
498 | $w->again |
285 | Similar to the "start" method, but has special semantics for |
499 | Similar to the "start" method, but has special semantics for |
286 | repeating timers: |
500 | repeating timers: |
287 | |
501 | |
… | |
… | |
298 | This behaviour is useful when you have a timeout for some IO |
512 | This behaviour is useful when you have a timeout for some IO |
299 | operation. You create a timer object with the same value for $after |
513 | operation. You create a timer object with the same value for $after |
300 | and $repeat, and then, in the read/write watcher, run the "again" |
514 | and $repeat, and then, in the read/write watcher, run the "again" |
301 | method on the timeout. |
515 | method on the timeout. |
302 | |
516 | |
|
|
517 | PERIODIC WATCHERS - to cron or not to cron? |
303 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
518 | $w = EV::periodic $at, $interval, $reschedule_cb, $callback |
304 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
519 | $w = EV::periodic_ns $at, $interval, $reschedule_cb, $callback |
|
|
520 | $w = $loop->periodic ($at, $interval, $reschedule_cb, $callback) |
|
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521 | $w = $loop->periodic_ns ($at, $interval, $reschedule_cb, $callback) |
305 | Similar to EV::timer, but is not based on relative timeouts but on |
522 | Similar to EV::timer, but is not based on relative timeouts but on |
306 | absolute times. Apart from creating "simple" timers that trigger |
523 | absolute times. Apart from creating "simple" timers that trigger |
307 | "at" the specified time, it can also be used for non-drifting |
524 | "at" the specified time, it can also be used for non-drifting |
308 | absolute timers and more complex, cron-like, setups that are not |
525 | absolute timers and more complex, cron-like, setups that are not |
309 | adversely affected by time jumps (i.e. when the system clock is |
526 | adversely affected by time jumps (i.e. when the system clock is |
310 | changed by explicit date -s or other means such as ntpd). It is also |
527 | changed by explicit date -s or other means such as ntpd). It is also |
311 | the most complex watcher type in EV. |
528 | the most complex watcher type in EV. |
312 | |
529 | |
313 | It has three distinct "modes": |
530 | It has three distinct "modes": |
314 | |
531 | |
315 | * absolute timer ($interval = $reschedule_cb = 0) |
532 | * absolute timer ($interval = $reschedule_cb = 0) |
|
|
533 | |
316 | This time simply fires at the wallclock time $at and doesn't |
534 | This time simply fires at the wallclock time $at and doesn't |
317 | repeat. It will not adjust when a time jump occurs, that is, if |
535 | repeat. It will not adjust when a time jump occurs, that is, if |
318 | it is to be run at January 1st 2011 then it will run when the |
536 | it is to be run at January 1st 2011 then it will run when the |
319 | system time reaches or surpasses this time. |
537 | system time reaches or surpasses this time. |
320 | |
538 | |
321 | * non-repeating interval timer ($interval > 0, $reschedule_cb = 0) |
539 | * repeating interval timer ($interval > 0, $reschedule_cb = 0) |
|
|
540 | |
322 | In this mode the watcher will always be scheduled to time out at |
541 | In this mode the watcher will always be scheduled to time out at |
323 | the next "$at + N * $interval" time (for some integer N) and |
542 | the next "$at + N * $interval" time (for some integer N) and |
324 | then repeat, regardless of any time jumps. |
543 | then repeat, regardless of any time jumps. |
325 | |
544 | |
326 | This can be used to create timers that do not drift with respect |
545 | This can be used to create timers that do not drift with respect |
… | |
… | |
335 | Another way to think about it (for the mathematically inclined) |
554 | Another way to think about it (for the mathematically inclined) |
336 | is that EV::periodic will try to run the callback in this mode |
555 | is that EV::periodic will try to run the callback in this mode |
337 | at the next possible time where "$time = $at (mod $interval)", |
556 | at the next possible time where "$time = $at (mod $interval)", |
338 | regardless of any time jumps. |
557 | regardless of any time jumps. |
339 | |
558 | |
340 | * manual reschedule mode ($reschedule_cb = coderef) |
559 | * manual reschedule mode ($reschedule_cb = coderef) |
|
|
560 | |
341 | In this mode $interval and $at are both being ignored. Instead, |
561 | In this mode $interval and $at are both being ignored. Instead, |
342 | each time the periodic watcher gets scheduled, the reschedule |
562 | each time the periodic watcher gets scheduled, the reschedule |
343 | callback ($reschedule_cb) will be called with the watcher as |
563 | callback ($reschedule_cb) will be called with the watcher as |
344 | first, and the current time as second argument. |
564 | first, and the current time as second argument. |
345 | |
565 | |
346 | *This callback MUST NOT stop or destroy this or any other |
566 | *This callback MUST NOT stop or destroy this or any other |
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|
567 | periodic watcher, ever, and MUST NOT call any event loop |
347 | periodic watcher, ever*. If you need to stop it, return 1e30 and |
568 | functions or methods*. If you need to stop it, return 1e30 and |
348 | stop it afterwards. |
569 | stop it afterwards. You may create and start a "EV::prepare" |
|
|
570 | watcher for this task. |
349 | |
571 | |
350 | It must return the next time to trigger, based on the passed |
572 | It must return the next time to trigger, based on the passed |
351 | time value (that is, the lowest time value larger than to the |
573 | time value (that is, the lowest time value larger than or equal |
352 | second argument). It will usually be called just before the |
574 | to to the second argument). It will usually be called just |
353 | callback will be triggered, but might be called at other times, |
575 | before the callback will be triggered, but might be called at |
354 | too. |
576 | other times, too. |
355 | |
577 | |
356 | This can be used to create very complex timers, such as a timer |
578 | This can be used to create very complex timers, such as a timer |
357 | that triggers on each midnight, local time (actually 24 hours |
579 | that triggers on each midnight, local time (actually 24 hours |
358 | after the last midnight, to keep the example simple. If you know |
580 | after the last midnight, to keep the example simple. If you know |
359 | a way to do it correctly in about the same space (without |
581 | a way to do it correctly in about the same space (without |
… | |
… | |
372 | The "periodic_ns" variant doesn't start (activate) the newly created |
594 | The "periodic_ns" variant doesn't start (activate) the newly created |
373 | watcher. |
595 | watcher. |
374 | |
596 | |
375 | $w->set ($at, $interval, $reschedule_cb) |
597 | $w->set ($at, $interval, $reschedule_cb) |
376 | Reconfigures the watcher, see the constructor above for details. Can |
598 | Reconfigures the watcher, see the constructor above for details. Can |
377 | be at any time. |
599 | be called at any time. |
378 | |
600 | |
379 | $w->again |
601 | $w->again |
380 | Simply stops and starts the watcher again. |
602 | Simply stops and starts the watcher again. |
381 | |
603 | |
|
|
604 | $time = $w->at |
|
|
605 | Return the time that the watcher is expected to trigger next. |
|
|
606 | |
|
|
607 | SIGNAL WATCHERS - signal me when a signal gets signalled! |
382 | $w = EV::signal $signal, $callback |
608 | $w = EV::signal $signal, $callback |
383 | $w = EV::signal_ns $signal, $callback |
609 | $w = EV::signal_ns $signal, $callback |
|
|
610 | $w = $loop->signal ($signal, $callback) |
|
|
611 | $w = $loop->signal_ns ($signal, $callback) |
384 | Call the callback when $signal is received (the signal can be |
612 | Call the callback when $signal is received (the signal can be |
385 | specified by number or by name, just as with kill or %SIG). |
613 | specified by number or by name, just as with "kill" or %SIG). |
|
|
614 | |
|
|
615 | Only one event loop can grab a given signal - attempting to grab the |
|
|
616 | same signal from two EV loops will crash the program immediately or |
|
|
617 | cause data corruption. |
386 | |
618 | |
387 | EV will grab the signal for the process (the kernel only allows one |
619 | EV will grab the signal for the process (the kernel only allows one |
388 | component to receive a signal at a time) when you start a signal |
620 | component to receive a signal at a time) when you start a signal |
389 | watcher, and removes it again when you stop it. Perl does the same |
621 | watcher, and removes it again when you stop it. Perl does the same |
390 | when you add/remove callbacks to %SIG, so watch out. |
622 | when you add/remove callbacks to %SIG, so watch out. |
… | |
… | |
394 | The "signal_ns" variant doesn't start (activate) the newly created |
626 | The "signal_ns" variant doesn't start (activate) the newly created |
395 | watcher. |
627 | watcher. |
396 | |
628 | |
397 | $w->set ($signal) |
629 | $w->set ($signal) |
398 | Reconfigures the watcher, see the constructor above for details. Can |
630 | Reconfigures the watcher, see the constructor above for details. Can |
399 | be at any time. |
631 | be called at any time. |
400 | |
632 | |
401 | $current_signum = $w->signal |
633 | $current_signum = $w->signal |
402 | $old_signum = $w->signal ($new_signal) |
634 | $old_signum = $w->signal ($new_signal) |
403 | Returns the previously set signal (always as a number not name) and |
635 | Returns the previously set signal (always as a number not name) and |
404 | optionally set a new one. |
636 | optionally set a new one. |
405 | |
637 | |
|
|
638 | CHILD WATCHERS - watch out for process status changes |
406 | $w = EV::child $pid, $callback |
639 | $w = EV::child $pid, $trace, $callback |
407 | $w = EV::child_ns $pid, $callback |
640 | $w = EV::child_ns $pid, $trace, $callback |
|
|
641 | $w = $loop->child ($pid, $trace, $callback) |
|
|
642 | $w = $loop->child_ns ($pid, $trace, $callback) |
408 | Call the callback when a status change for pid $pid (or any pid if |
643 | Call the callback when a status change for pid $pid (or any pid if |
409 | $pid is 0) has been received. More precisely: when the process |
644 | $pid is 0) has been received (a status change happens when the |
|
|
645 | process terminates or is killed, or, when trace is true, |
|
|
646 | additionally when it is stopped or continued). More precisely: when |
410 | receives a SIGCHLD, EV will fetch the outstanding exit/wait status |
647 | the process receives a "SIGCHLD", EV will fetch the outstanding |
411 | for all changed/zombie children and call the callback. |
648 | exit/wait status for all changed/zombie children and call the |
|
|
649 | callback. |
412 | |
650 | |
413 | You can access both status and pid by using the "rstatus" and "rpid" |
651 | It is valid (and fully supported) to install a child watcher after a |
|
|
652 | child has exited but before the event loop has started its next |
|
|
653 | iteration (for example, first you "fork", then the new child process |
|
|
654 | might exit, and only then do you install a child watcher in the |
|
|
655 | parent for the new pid). |
|
|
656 | |
|
|
657 | You can access both exit (or tracing) status and pid by using the |
414 | methods on the watcher object. |
658 | "rstatus" and "rpid" methods on the watcher object. |
415 | |
659 | |
416 | You can have as many pid watchers per pid as you want. |
660 | You can have as many pid watchers per pid as you want, they will all |
|
|
661 | be called. |
417 | |
662 | |
418 | The "child_ns" variant doesn't start (activate) the newly created |
663 | The "child_ns" variant doesn't start (activate) the newly created |
419 | watcher. |
664 | watcher. |
420 | |
665 | |
421 | $w->set ($pid) |
666 | $w->set ($pid, $trace) |
422 | Reconfigures the watcher, see the constructor above for details. Can |
667 | Reconfigures the watcher, see the constructor above for details. Can |
423 | be at any time. |
668 | be called at any time. |
424 | |
669 | |
425 | $current_pid = $w->pid |
670 | $current_pid = $w->pid |
426 | $old_pid = $w->pid ($new_pid) |
|
|
427 | Returns the previously set process id and optionally set a new one. |
671 | Returns the previously set process id and optionally set a new one. |
428 | |
672 | |
429 | $exit_status = $w->rstatus |
673 | $exit_status = $w->rstatus |
430 | Return the exit/wait status (as returned by waitpid, see the waitpid |
674 | Return the exit/wait status (as returned by waitpid, see the waitpid |
431 | entry in perlfunc). |
675 | entry in perlfunc). |
432 | |
676 | |
433 | $pid = $w->rpid |
677 | $pid = $w->rpid |
434 | Return the pid of the awaited child (useful when you have installed |
678 | Return the pid of the awaited child (useful when you have installed |
435 | a watcher for all pids). |
679 | a watcher for all pids). |
436 | |
680 | |
|
|
681 | STAT WATCHERS - did the file attributes just change? |
|
|
682 | $w = EV::stat $path, $interval, $callback |
|
|
683 | $w = EV::stat_ns $path, $interval, $callback |
|
|
684 | $w = $loop->stat ($path, $interval, $callback) |
|
|
685 | $w = $loop->stat_ns ($path, $interval, $callback) |
|
|
686 | Call the callback when a file status change has been detected on |
|
|
687 | $path. The $path does not need to exist, changing from "path exists" |
|
|
688 | to "path does not exist" is a status change like any other. |
|
|
689 | |
|
|
690 | The $interval is a recommended polling interval for systems where |
|
|
691 | OS-supported change notifications don't exist or are not supported. |
|
|
692 | If you use 0 then an unspecified default is used (which is highly |
|
|
693 | recommended!), which is to be expected to be around five seconds |
|
|
694 | usually. |
|
|
695 | |
|
|
696 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
697 | as even with OS-supported change notifications, this can be |
|
|
698 | resource-intensive. |
|
|
699 | |
|
|
700 | The "stat_ns" variant doesn't start (activate) the newly created |
|
|
701 | watcher. |
|
|
702 | |
|
|
703 | ... = $w->stat |
|
|
704 | This call is very similar to the perl "stat" built-in: It stats |
|
|
705 | (using "lstat") the path specified in the watcher and sets perls |
|
|
706 | stat cache (as well as EV's idea of the current stat values) to the |
|
|
707 | values found. |
|
|
708 | |
|
|
709 | In scalar context, a boolean is return indicating success or failure |
|
|
710 | of the stat. In list context, the same 13-value list as with stat is |
|
|
711 | returned (except that the blksize and blocks fields are not |
|
|
712 | reliable). |
|
|
713 | |
|
|
714 | In the case of an error, errno is set to "ENOENT" (regardless of the |
|
|
715 | actual error value) and the "nlink" value is forced to zero (if the |
|
|
716 | stat was successful then nlink is guaranteed to be non-zero). |
|
|
717 | |
|
|
718 | See also the next two entries for more info. |
|
|
719 | |
|
|
720 | ... = $w->attr |
|
|
721 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
722 | the values most recently detected by EV. See the next entry for more |
|
|
723 | info. |
|
|
724 | |
|
|
725 | ... = $w->prev |
|
|
726 | Just like "$w->stat", but without the initial stat'ing: this returns |
|
|
727 | the previous set of values, before the change. |
|
|
728 | |
|
|
729 | That is, when the watcher callback is invoked, "$w->prev" will be |
|
|
730 | set to the values found *before* a change was detected, while |
|
|
731 | "$w->attr" returns the values found leading to the change detection. |
|
|
732 | The difference (if any) between "prev" and "attr" is what triggered |
|
|
733 | the callback. |
|
|
734 | |
|
|
735 | If you did something to the filesystem object and do not want to |
|
|
736 | trigger yet another change, you can call "stat" to update EV's idea |
|
|
737 | of what the current attributes are. |
|
|
738 | |
|
|
739 | $w->set ($path, $interval) |
|
|
740 | Reconfigures the watcher, see the constructor above for details. Can |
|
|
741 | be called at any time. |
|
|
742 | |
|
|
743 | $current_path = $w->path |
|
|
744 | $old_path = $w->path ($new_path) |
|
|
745 | Returns the previously set path and optionally set a new one. |
|
|
746 | |
|
|
747 | $current_interval = $w->interval |
|
|
748 | $old_interval = $w->interval ($new_interval) |
|
|
749 | Returns the previously set interval and optionally set a new one. |
|
|
750 | Can be used to query the actual interval used. |
|
|
751 | |
|
|
752 | IDLE WATCHERS - when you've got nothing better to do... |
437 | $w = EV::idle $callback |
753 | $w = EV::idle $callback |
438 | $w = EV::idle_ns $callback |
754 | $w = EV::idle_ns $callback |
|
|
755 | $w = $loop->idle ($callback) |
|
|
756 | $w = $loop->idle_ns ($callback) |
439 | Call the callback when there are no pending io, timer/periodic, |
757 | Call the callback when there are no other pending watchers of the |
440 | signal or child events, i.e. when the process is idle. |
758 | same or higher priority (excluding check, prepare and other idle |
|
|
759 | watchers of the same or lower priority, of course). They are called |
|
|
760 | idle watchers because when the watcher is the highest priority |
|
|
761 | pending event in the process, the process is considered to be idle |
|
|
762 | at that priority. |
|
|
763 | |
|
|
764 | If you want a watcher that is only ever called when *no* other |
|
|
765 | events are outstanding you have to set the priority to "EV::MINPRI". |
441 | |
766 | |
442 | The process will not block as long as any idle watchers are active, |
767 | The process will not block as long as any idle watchers are active, |
443 | and they will be called repeatedly until stopped. |
768 | and they will be called repeatedly until stopped. |
444 | |
769 | |
|
|
770 | For example, if you have idle watchers at priority 0 and 1, and an |
|
|
771 | I/O watcher at priority 0, then the idle watcher at priority 1 and |
|
|
772 | the I/O watcher will always run when ready. Only when the idle |
|
|
773 | watcher at priority 1 is stopped and the I/O watcher at priority 0 |
|
|
774 | is not pending with the 0-priority idle watcher be invoked. |
|
|
775 | |
445 | The "idle_ns" variant doesn't start (activate) the newly created |
776 | The "idle_ns" variant doesn't start (activate) the newly created |
446 | watcher. |
777 | watcher. |
447 | |
778 | |
|
|
779 | PREPARE WATCHERS - customise your event loop! |
448 | $w = EV::prepare $callback |
780 | $w = EV::prepare $callback |
449 | $w = EV::prepare_ns $callback |
781 | $w = EV::prepare_ns $callback |
|
|
782 | $w = $loop->prepare ($callback) |
|
|
783 | $w = $loop->prepare_ns ($callback) |
450 | Call the callback just before the process would block. You can still |
784 | Call the callback just before the process would block. You can still |
451 | create/modify any watchers at this point. |
785 | create/modify any watchers at this point. |
452 | |
786 | |
453 | See the EV::check watcher, below, for explanations and an example. |
787 | See the EV::check watcher, below, for explanations and an example. |
454 | |
788 | |
455 | The "prepare_ns" variant doesn't start (activate) the newly created |
789 | The "prepare_ns" variant doesn't start (activate) the newly created |
456 | watcher. |
790 | watcher. |
457 | |
791 | |
|
|
792 | CHECK WATCHERS - customise your event loop even more! |
458 | $w = EV::check $callback |
793 | $w = EV::check $callback |
459 | $w = EV::check_ns $callback |
794 | $w = EV::check_ns $callback |
|
|
795 | $w = $loop->check ($callback) |
|
|
796 | $w = $loop->check_ns ($callback) |
460 | Call the callback just after the process wakes up again (after it |
797 | Call the callback just after the process wakes up again (after it |
461 | has gathered events), but before any other callbacks have been |
798 | has gathered events), but before any other callbacks have been |
462 | invoked. |
799 | invoked. |
463 | |
800 | |
464 | This is used to integrate other event-based software into the EV |
801 | This can be used to integrate other event-based software into the EV |
465 | mainloop: You register a prepare callback and in there, you create |
802 | mainloop: You register a prepare callback and in there, you create |
466 | io and timer watchers as required by the other software. Here is a |
803 | io and timer watchers as required by the other software. Here is a |
467 | real-world example of integrating Net::SNMP (with some details left |
804 | real-world example of integrating Net::SNMP (with some details left |
468 | out): |
805 | out): |
469 | |
806 | |
… | |
… | |
475 | or return; |
812 | or return; |
476 | |
813 | |
477 | # make the dispatcher handle any outstanding stuff |
814 | # make the dispatcher handle any outstanding stuff |
478 | ... not shown |
815 | ... not shown |
479 | |
816 | |
480 | # create an IO watcher for each and every socket |
817 | # create an I/O watcher for each and every socket |
481 | @snmp_watcher = ( |
818 | @snmp_watcher = ( |
482 | (map { EV::io $_, EV::READ, sub { } } |
819 | (map { EV::io $_, EV::READ, sub { } } |
483 | keys %{ $dispatcher->{_descriptors} }), |
820 | keys %{ $dispatcher->{_descriptors} }), |
484 | |
821 | |
485 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
822 | EV::timer +($event->[Net::SNMP::Dispatcher::_ACTIVE] |
… | |
… | |
500 | # make the dispatcher handle any new stuff |
837 | # make the dispatcher handle any new stuff |
501 | ... not shown |
838 | ... not shown |
502 | }; |
839 | }; |
503 | |
840 | |
504 | The callbacks of the created watchers will not be called as the |
841 | The callbacks of the created watchers will not be called as the |
505 | watchers are destroyed before this cna happen (remember EV::check |
842 | watchers are destroyed before this can happen (remember EV::check |
506 | gets called first). |
843 | gets called first). |
507 | |
844 | |
508 | The "check_ns" variant doesn't start (activate) the newly created |
845 | The "check_ns" variant doesn't start (activate) the newly created |
509 | watcher. |
846 | watcher. |
510 | |
847 | |
|
|
848 | EV::CHECK constant issues |
|
|
849 | Like all other watcher types, there is a bitmask constant for use in |
|
|
850 | $revents and other places. The "EV::CHECK" is special as it has the |
|
|
851 | same name as the "CHECK" sub called by Perl. This doesn't cause big |
|
|
852 | issues on newer perls (beginning with 5.8.9), but it means thatthe |
|
|
853 | constant must be *inlined*, i.e. runtime calls will not work. That |
|
|
854 | means that as long as you always "use EV" and then "EV::CHECK" you |
|
|
855 | are on the safe side. |
|
|
856 | |
|
|
857 | FORK WATCHERS - the audacity to resume the event loop after a fork |
|
|
858 | Fork watchers are called when a "fork ()" was detected. The invocation |
|
|
859 | is done before the event loop blocks next and before "check" watchers |
|
|
860 | are being called, and only in the child after the fork. |
|
|
861 | |
|
|
862 | $w = EV::fork $callback |
|
|
863 | $w = EV::fork_ns $callback |
|
|
864 | $w = $loop->fork ($callback) |
|
|
865 | $w = $loop->fork_ns ($callback) |
|
|
866 | Call the callback before the event loop is resumed in the child |
|
|
867 | process after a fork. |
|
|
868 | |
|
|
869 | The "fork_ns" variant doesn't start (activate) the newly created |
|
|
870 | watcher. |
|
|
871 | |
|
|
872 | EMBED WATCHERS - when one backend isn't enough... |
|
|
873 | This is a rather advanced watcher type that lets you embed one event |
|
|
874 | loop into another (currently only IO events are supported in the |
|
|
875 | embedded loop, other types of watchers might be handled in a delayed or |
|
|
876 | incorrect fashion and must not be used). |
|
|
877 | |
|
|
878 | See the libev documentation at |
|
|
879 | <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#code_ev_embed_code |
|
|
880 | _when_one_backend_> (locally installed as EV::libev) for more details. |
|
|
881 | |
|
|
882 | In short, this watcher is most useful on BSD systems without working |
|
|
883 | kqueue to still be able to handle a large number of sockets: |
|
|
884 | |
|
|
885 | my $socket_loop; |
|
|
886 | |
|
|
887 | # check wether we use SELECT or POLL _and_ KQUEUE is supported |
|
|
888 | if ( |
|
|
889 | (EV::backend & (EV::BACKEND_POLL | EV::BACKEND_SELECT)) |
|
|
890 | && (EV::supported_backends & EV::embeddable_backends & EV::BACKEND_KQUEUE) |
|
|
891 | ) { |
|
|
892 | # use kqueue for sockets |
|
|
893 | $socket_loop = new EV::Loop EV::BACKEND_KQUEUE | EV::FLAG_NOENV; |
|
|
894 | } |
|
|
895 | |
|
|
896 | # use the default loop otherwise |
|
|
897 | $socket_loop ||= EV::default_loop; |
|
|
898 | |
|
|
899 | $w = EV::embed $otherloop[, $callback] |
|
|
900 | $w = EV::embed_ns $otherloop[, $callback] |
|
|
901 | $w = $loop->embed ($otherloop[, $callback]) |
|
|
902 | $w = $loop->embed_ns ($otherloop[, $callback]) |
|
|
903 | Call the callback when the embedded event loop ($otherloop) has any |
|
|
904 | I/O activity. The $callback is optional: if it is missing, then the |
|
|
905 | embedded event loop will be managed automatically (which is |
|
|
906 | recommended), otherwise you have to invoke "sweep" yourself. |
|
|
907 | |
|
|
908 | The "embed_ns" variant doesn't start (activate) the newly created |
|
|
909 | watcher. |
|
|
910 | |
|
|
911 | ASYNC WATCHERS - how to wake up another event loop |
|
|
912 | Async watchers are provided by EV, but have little use in perl directly, |
|
|
913 | as perl neither supports threads running in parallel nor direct access |
|
|
914 | to signal handlers or other contexts where they could be of value. |
|
|
915 | |
|
|
916 | It is, however, possible to use them from the XS level. |
|
|
917 | |
|
|
918 | Please see the libev documentation for further details. |
|
|
919 | |
|
|
920 | $w = EV::async $callback |
|
|
921 | $w = EV::async_ns $callback |
|
|
922 | $w->send |
|
|
923 | $bool = $w->async_pending |
|
|
924 | |
|
|
925 | PERL SIGNALS |
|
|
926 | While Perl signal handling (%SIG) is not affected by EV, the behaviour |
|
|
927 | with EV is as the same as any other C library: Perl-signals will only be |
|
|
928 | handled when Perl runs, which means your signal handler might be invoked |
|
|
929 | only the next time an event callback is invoked. |
|
|
930 | |
|
|
931 | The solution is to use EV signal watchers (see "EV::signal"), which will |
|
|
932 | ensure proper operations with regards to other event watchers. |
|
|
933 | |
|
|
934 | If you cannot do this for whatever reason, you can also force a watcher |
|
|
935 | to be called on every event loop iteration by installing a "EV::check" |
|
|
936 | watcher: |
|
|
937 | |
|
|
938 | my $async_check = EV::check sub { }; |
|
|
939 | |
|
|
940 | This ensures that perl gets into control for a short time to handle any |
|
|
941 | pending signals, and also ensures (slightly) slower overall operation. |
|
|
942 | |
511 | THREADS |
943 | ITHREADS |
512 | Threads are not supported by this module in any way. Perl pseudo-threads |
944 | Ithreads are not supported by this module in any way. Perl |
513 | is evil stuff and must die. As soon as Perl gains real threads I will |
945 | pseudo-threads is evil stuff and must die. Real threads as provided by |
514 | work on thread support for it. |
946 | Coro are fully supported (and enhanced support is available via |
|
|
947 | Coro::EV). |
515 | |
948 | |
516 | FORK |
949 | FORK |
517 | Most of the "improved" event delivering mechanisms of modern operating |
950 | Most of the "improved" event delivering mechanisms of modern operating |
518 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
951 | systems have quite a few problems with fork(2) (to put it bluntly: it is |
519 | not supported and usually destructive). Libev makes it possible to work |
952 | not supported and usually destructive). Libev makes it possible to work |
… | |
… | |
529 | |
962 | |
530 | On win32, there is no notion of fork so all this doesn't apply, of |
963 | On win32, there is no notion of fork so all this doesn't apply, of |
531 | course. |
964 | course. |
532 | |
965 | |
533 | SEE ALSO |
966 | SEE ALSO |
534 | L<EV::DNS>. |
967 | EV::MakeMaker - MakeMaker interface to XS API, EV::ADNS (asynchronous |
|
|
968 | DNS), Glib::EV (makes Glib/Gtk2 use EV as event loop), EV::Glib (embed |
|
|
969 | Glib into EV), Coro::EV (efficient thread integration), Net::SNMP::EV |
|
|
970 | (asynchronous SNMP), AnyEvent for event-loop agnostic and portable event |
|
|
971 | driven programming. |
535 | |
972 | |
536 | AUTHOR |
973 | AUTHOR |
537 | Marc Lehmann <schmorp@schmorp.de> |
974 | Marc Lehmann <schmorp@schmorp.de> |
538 | http://home.schmorp.de/ |
975 | http://home.schmorp.de/ |
539 | |
976 | |