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1 | package threads; |
2 | |
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3 | use 5.007_003; |
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4 | use strict; |
5 | use warnings; |
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6 | use Config; |
7 | |
8 | BEGIN { |
9 | unless ($Config{useithreads}) { |
10 | my @caller = caller(2); |
11 | die <<EOF; |
12 | $caller[1] line $caller[2]: |
13 | |
14 | This Perl hasn't been configured and built properly for the threads |
15 | module to work. (The 'useithreads' configuration option hasn't been used.) |
16 | |
17 | Having threads support requires all of Perl and all of the modules in |
18 | the Perl installation to be rebuilt, it is not just a question of adding |
19 | the threads module. (In other words, threaded and non-threaded Perls |
20 | are binary incompatible.) |
21 | |
22 | If you want to the use the threads module, please contact the people |
23 | who built your Perl. |
24 | |
25 | Cannot continue, aborting. |
26 | EOF |
27 | } |
28 | } |
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29 | |
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30 | use overload |
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31 | '==' => \&equal, |
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32 | 'fallback' => 1; |
33 | |
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34 | #use threads::Shared; |
35 | |
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36 | BEGIN { |
37 | warn "Warning, threads::shared has already been loaded. ". |
38 | "To enable shared variables for these modules 'use threads' ". |
39 | "must be called before any of those modules are loaded\n" |
40 | if($threads::shared::threads_shared); |
41 | } |
42 | |
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43 | require Exporter; |
44 | require DynaLoader; |
45 | |
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46 | our @ISA = qw(Exporter DynaLoader); |
47 | |
48 | our %EXPORT_TAGS = ( all => [qw()]); |
49 | |
50 | our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } ); |
51 | |
52 | our @EXPORT = qw( |
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53 | async |
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54 | ); |
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55 | our $VERSION = '0.99'; |
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56 | |
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57 | |
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58 | sub equal { |
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59 | return 1 if($_[0]->tid() == $_[1]->tid()); |
60 | return 0; |
61 | } |
62 | |
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63 | sub async (&;@) { |
64 | my $cref = shift; |
65 | return threads->new($cref,@_); |
66 | } |
67 | |
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68 | $threads::threads = 1; |
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69 | |
70 | bootstrap threads $VERSION; |
71 | |
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72 | # why document 'new' then use 'create' in the tests! |
73 | *create = \&new; |
74 | |
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75 | # Preloaded methods go here. |
76 | |
77 | 1; |
78 | __END__ |
79 | |
80 | =head1 NAME |
81 | |
82 | threads - Perl extension allowing use of interpreter based threads from perl |
83 | |
84 | =head1 SYNOPSIS |
85 | |
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86 | use threads; |
87 | |
88 | sub start_thread { |
89 | print "Thread started\n"; |
90 | } |
91 | |
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92 | my $thread = threads->create("start_thread","argument"); |
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93 | |
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94 | $thread->create(sub { print "I am a thread"},"argument"); |
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95 | |
96 | $thread->join(); |
97 | |
98 | $thread->detach(); |
99 | |
100 | $thread = threads->self(); |
101 | |
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102 | threads->tid(); |
103 | threads->self->tid(); |
104 | |
105 | $thread->tid(); |
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106 | |
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107 | threads->yield(); |
108 | |
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109 | threads->list(); |
110 | |
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111 | =head1 DESCRIPTION |
112 | |
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113 | Perl 5.6 introduced something called interpreter threads. Interpreter |
114 | threads are different from "5005threads" (the thread model of Perl |
115 | 5.005) by creating a new perl interpreter per thread and not sharing |
116 | any data or state between threads. |
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117 | |
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118 | Prior to perl 5.8 this has only been available to people embedding |
119 | perl and for emulating fork() on windows. |
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120 | |
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121 | The threads API is loosely based on the old Thread.pm API. It is very |
122 | important to note that variables are not shared between threads, all |
123 | variables are per default thread local. To use shared variables one |
124 | must use threads::shared. |
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125 | |
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126 | It is also important to note that you preferably enable threads by |
127 | doing C<use threads> as early as possible and that it is not possible |
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128 | to enable threading inside an eval ""; In particular, if you are |
129 | intending to share variables with threads::shared, you must |
130 | C<use threads> before you C<use threads::shared> and threads will emit |
131 | a warning if you do it the other way around. |
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132 | |
133 | =over |
134 | |
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135 | =item $thread = threads->create(function, LIST) |
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136 | |
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137 | This will create a new thread with the entry point function and give |
138 | it LIST as parameters. It will return the corresponding threads |
139 | object. |
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140 | |
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141 | =item $thread->join |
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142 | |
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143 | This will wait for the corresponding thread to join. When it finishes |
144 | join will return the return values of the entry point function. If a |
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145 | thread has been detached, an error will be thrown.. |
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146 | |
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147 | =item $thread->detach |
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148 | |
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149 | Will throw away the return value from the thread and make it |
150 | non-joinable. |
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151 | |
152 | =item threads->self |
153 | |
154 | This will return the object for the current thread. |
155 | |
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156 | =item $thread->tid |
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157 | |
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158 | This will return the id of the thread. threads->tid() is a quick way |
159 | to get current thread id if you don't have your thread handy. |
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160 | |
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161 | =item threads->yield(); |
162 | |
163 | This will tell the OS to let this thread yield CPU time to other threads. |
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164 | However this is highly depending on the underlying thread implementation. |
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165 | |
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166 | =item threads->list(); |
167 | |
168 | This will return a list of all non joined, non detached threads. |
169 | |
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170 | =item async BLOCK; |
171 | |
172 | C<async> creates a thread to execute the block immediately following |
173 | it. This block is treated as an anonymous sub, and so must have a |
174 | semi-colon after the closing brace. Like C<threads->new>, C<async> |
175 | returns a thread object. |
176 | |
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177 | =back |
178 | |
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179 | =head1 WARNINGS |
180 | |
181 | =over 4 |
182 | |
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183 | =item A thread exited while %d other threads were still running |
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184 | |
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185 | A thread (not necessarily the main thread) exited while there were |
186 | still other threads running. Usually it's a good idea to first collect |
187 | the return values of the created threads by joining them, and only then |
188 | exit from then main thread. |
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189 | |
190 | =back |
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191 | |
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192 | =head1 BUGS / TODO |
193 | |
194 | The current implmentation of threads has been an attempt to get |
195 | a correct threading system working that could be built on, |
196 | and optimized, in newer versions of perl. |
197 | |
198 | Current the overhead of creating a thread is rather large, |
199 | also the cost of returning values can be large. These are areas |
200 | were there most likely will be work done to optimize what data |
201 | that needs to be cloned. |
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202 | |
203 | =over |
204 | |
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205 | =item Parent-Child threads. |
206 | |
207 | On some platforms it might not be possible to destroy "parent" |
208 | threads while there are still existing child "threads". |
209 | |
210 | This will be possibly be fixed in later versions of perl. |
211 | |
212 | =item tid is I32 |
213 | |
214 | The tid is a 32 bit integer, it can potentially overflow. |
215 | This might be fixed in a later version of perl. |
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216 | |
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217 | =item Returning objects |
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218 | |
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219 | When you return an object the entire stash that the object is blessed |
220 | as well. This will lead to a large memory usage. |
221 | The ideal situation would be to detect the original stash if it existed. |
222 | |
223 | =item PERL_OLD_SIGNALS are not threadsafe, will not be. |
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224 | |
225 | =back |
226 | |
227 | =head1 AUTHOR and COPYRIGHT |
228 | |
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229 | Arthur Bergman E<lt>arthur at contiller.seE<gt> |
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230 | |
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231 | threads is released under the same license as Perl. |
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232 | |
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233 | Thanks to |
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234 | |
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235 | Richard Soderberg E<lt>rs at crystalflame.netE<gt> |
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236 | Helping me out tons, trying to find reasons for races and other weird bugs! |
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237 | |
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238 | Simon Cozens E<lt>simon at brecon.co.ukE<gt> |
239 | Being there to answer zillions of annoying questions |
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240 | |
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241 | Rocco Caputo E<lt>troc at netrus.netE<gt> |
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242 | |
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243 | Vipul Ved Prakash E<lt>mail at vipul.netE<gt> |
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244 | Helping with debugging. |
245 | |
246 | please join perl-ithreads@perl.org for more information |
247 | |
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248 | |
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249 | |
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250 | |
251 | =head1 SEE ALSO |
252 | |
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253 | L<perl>, L<threads::shared>, L<perlcall>, L<perlembed>, L<perlguts> |
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254 | |
255 | =cut |