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1 | package threads::shared; |
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2 | |
3 | use 5.007_003; |
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4 | use strict; |
5 | use warnings; |
6 | use Config; |
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7 | |
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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 | } |
29 | |
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30 | require Exporter; |
31 | our @ISA = qw(Exporter); |
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32 | our @EXPORT = qw(share cond_wait cond_broadcast cond_signal _refcnt _id _thrcnt); |
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33 | our $VERSION = '0.90'; |
34 | |
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35 | use Attribute::Handlers; |
36 | |
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37 | |
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38 | if ($Config{'useithreads'}) { |
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39 | *cond_wait = \&cond_wait_enabled; |
40 | *cond_signal = \&cond_signal_enabled; |
41 | *cond_broadcast = \&cond_broadcast_enabled; |
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42 | require XSLoader; |
43 | XSLoader::load('threads::shared',$VERSION); |
44 | } |
45 | else { |
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46 | *share = \&share_disabled; |
47 | *cond_wait = \&cond_wait_disabled; |
48 | *cond_signal = \&cond_signal_disabled; |
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49 | *cond_broadcast = \&cond_broadcast_disabled; |
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50 | } |
51 | |
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52 | |
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53 | sub cond_wait_disabled { return @_ }; |
54 | sub cond_signal_disabled { return @_}; |
55 | sub cond_broadcast_disabled { return @_}; |
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56 | sub share_disabled { return @_} |
57 | |
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58 | $threads::shared::threads_shared = 1; |
59 | |
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60 | sub _thrcnt { 42 } |
61 | |
62 | sub threads::shared::tie::SPLICE |
63 | { |
64 | die "Splice not implemented for shared arrays"; |
65 | } |
66 | |
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67 | sub UNIVERSAL::shared : ATTR { |
68 | my ($package, $symbol, $referent, $attr, $data, $phase) = @_; |
69 | share($referent); |
70 | } |
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71 | |
72 | __END__ |
73 | |
74 | =head1 NAME |
75 | |
76 | threads::shared - Perl extension for sharing data structures between threads |
77 | |
78 | =head1 SYNOPSIS |
79 | |
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80 | use threads; |
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81 | use threads::shared; |
82 | |
83 | my($foo, @foo, %foo); |
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84 | share($foo); |
85 | share(@foo); |
86 | share(%hash); |
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87 | my $bar = share([]); |
88 | $hash{bar} = share({}); |
89 | |
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90 | lock(%hash); |
91 | unlock(%hash); |
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92 | cond_wait($scalar); |
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93 | cond_broadcast(@array); |
94 | cond_signal(%hash); |
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95 | |
96 | =head1 DESCRIPTION |
97 | |
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98 | This modules allows you to share() variables. These variables will |
99 | then be shared across different threads (and pseudoforks on |
100 | win32). They are used together with the threads module. |
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101 | |
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102 | =head1 EXPORT |
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103 | |
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104 | C<share>, C<lock>, C<unlock>, C<cond_wait>, C<cond_signal>, C<cond_broadcast> |
105 | |
106 | =head1 FUNCTIONS |
107 | |
108 | =over 4 |
109 | |
110 | =item share VARIABLE |
111 | |
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112 | C<share> takes a value and marks it as shared, you can share a scalar, array, hash |
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113 | scalar ref, array ref and hash ref, C<share> will return the shared value. |
114 | |
115 | C<share> will traverse up references exactly I<one> level. |
116 | C<share(\$a)> is equivalent to C<share($a)>, while C<share(\\$a)> is not. |
117 | |
118 | =item lock VARIABLE |
119 | |
120 | C<lock> places a lock on a variable until the lock goes out of scope. If |
121 | the variable is locked by another thread, the C<lock> call will block until |
122 | it's available. C<lock> is recursive, so multiple calls to C<lock> are |
123 | safe--the variable will remain locked until the outermost lock on the |
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124 | variable goes out of scope or C<unlock> is called enough times to match |
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125 | the number of calls to <lock>. |
126 | |
127 | If a container object, such as a hash or array, is locked, all the elements |
128 | of that container are not locked. For example, if a thread does a C<lock |
129 | @a>, any other thread doing a C<lock($a[12])> won't block. |
130 | |
131 | C<lock> will traverse up references exactly I<one> level. |
132 | C<lock(\$a)> is equivalent to C<lock($a)>, while C<lock(\\$a)> is not. |
133 | |
134 | |
135 | =item unlock VARIABLE |
136 | |
137 | C<unlock> takes a locked shared value and decrements the lock count. |
138 | If the lock count is zero the variable is unlocked. It is not necessary |
139 | to call C<unlock> but it can be usefull to reduce lock contention. |
140 | |
141 | C<unlock> will traverse up references exactly I<one> level. |
142 | C<unlock(\$a)> is equivalent to C<unlock($a)>, while C<unlock(\\$a)> is not. |
143 | |
144 | =item cond_wait VARIABLE |
145 | |
146 | The C<cond_wait> function takes a B<locked> variable as a parameter, |
147 | unlocks the variable, and blocks until another thread does a C<cond_signal> |
148 | or C<cond_broadcast> for that same locked variable. The variable that |
149 | C<cond_wait> blocked on is relocked after the C<cond_wait> is satisfied. |
150 | If there are multiple threads C<cond_wait>ing on the same variable, all but |
151 | one will reblock waiting to reaquire the lock on the variable. (So if |
152 | you're only using C<cond_wait> for synchronization, give up the lock as |
153 | soon as possible) |
154 | |
155 | It is important to note that the variable can be notified even if no |
156 | thread C<cond_signal> or C<cond_broadcast> on the variable. It is therefore |
157 | important to check the value of the variable and go back to waiting if the |
158 | requirment is not fullfilled. |
159 | |
160 | =item cond_signal VARIABLE |
161 | |
162 | The C<cond_signal> function takes a B<locked> variable as a parameter and |
163 | unblocks one thread that's C<cond_wait>ing on that variable. If more than |
164 | one thread is blocked in a C<cond_wait> on that variable, only one (and |
165 | which one is indeterminate) will be unblocked. |
166 | |
167 | If there are no threads blocked in a C<cond_wait> on the variable, the |
168 | signal is discarded. |
169 | |
170 | =item cond_broadcast VARIABLE |
171 | |
172 | The C<cond_broadcast> function works similarly to C<cond_signal>. |
173 | C<cond_broadcast>, though, will unblock B<all> the threads that are blocked |
174 | in a C<cond_wait> on the locked variable, rather than only one. |
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175 | |
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176 | |
177 | =head1 NOTES |
178 | |
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179 | threads::shared is designed to disable itself silently if threads are |
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180 | not available. If you want access to threads, you must C<use threads> |
181 | before you C<use threads::shared>. threads will emit a warning if you |
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182 | use it after threads::shared. |
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183 | |
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184 | =head1 BUGS |
185 | |
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186 | C<bless> is not supported on shared references, in the current version |
187 | C<bless> will only bless the thread local reference and the blessing |
188 | will not propagate to the other threads, this is expected to be implmented |
189 | in the future. |
190 | |
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191 | Does not support splice on arrays! |
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192 | |
193 | =head1 AUTHOR |
194 | |
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195 | Arthur Bergman E<lt>arthur at contiller.seE<gt> |
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196 | |
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197 | threads::shared is released under the same license as Perl |
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198 | |
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199 | Documentation borrowed from Thread.pm |
200 | |
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201 | =head1 SEE ALSO |
202 | |
203 | L<perl> L<threads> |
204 | |
205 | =cut |
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206 | |
207 | |
208 | |
209 | |
210 | |