… | |
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2 | |
2 | |
3 | Coro - coroutine process abstraction |
3 | Coro - coroutine process abstraction |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
9 | async { |
9 | async { |
10 | # some asynchronous thread of execution |
10 | # some asynchronous thread of execution |
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11 | print "2\n"; |
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12 | cede; # yield back to main |
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13 | print "4\n"; |
11 | }; |
14 | }; |
12 | |
15 | print "1\n"; |
13 | # alternatively create an async coroutine like this: |
16 | cede; # yield to coroutine |
14 | |
17 | print "3\n"; |
15 | sub some_func : Coro { |
18 | cede; # and again |
16 | # some more async code |
19 | |
17 | } |
20 | # use locking |
18 | |
21 | use Coro::Semaphore; |
19 | cede; |
22 | my $lock = new Coro::Semaphore; |
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23 | my $locked; |
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24 | |
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25 | $lock->down; |
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26 | $locked = 1; |
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27 | $lock->up; |
20 | |
28 | |
21 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
22 | |
30 | |
23 | This module collection manages coroutines. Coroutines are similar |
31 | This module collection manages coroutines. Coroutines are similar to |
24 | to threads but don't run in parallel at the same time even on SMP |
32 | threads but don't (in general) run in parallel at the same time even |
25 | machines. The specific flavor of coroutine used in this module also |
33 | on SMP machines. The specific flavor of coroutine used in this module |
26 | guarantees you that it will not switch between coroutines unless |
34 | also guarantees you that it will not switch between coroutines unless |
27 | necessary, at easily-identified points in your program, so locking and |
35 | necessary, at easily-identified points in your program, so locking and |
28 | parallel access are rarely an issue, making coroutine programming much |
36 | parallel access are rarely an issue, making coroutine programming much |
29 | safer than threads programming. |
37 | safer and easier than threads programming. |
30 | |
38 | |
31 | (Perl, however, does not natively support real threads but instead does a |
39 | Unlike a normal perl program, however, coroutines allow you to have |
32 | very slow and memory-intensive emulation of processes using threads. This |
40 | multiple running interpreters that share data, which is especially useful |
33 | is a performance win on Windows machines, and a loss everywhere else). |
41 | to code pseudo-parallel processes and for event-based programming, such as |
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42 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
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43 | learn more. |
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44 | |
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45 | Coroutines are also useful because Perl has no support for threads (the so |
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46 | called "threads" that perl offers are nothing more than the (bad) process |
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47 | emulation coming from the Windows platform: On standard operating systems |
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48 | they serve no purpose whatsoever, except by making your programs slow and |
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49 | making them use a lot of memory. Best disable them when building perl, or |
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50 | aks your software vendor/distributor to do it for you). |
34 | |
51 | |
35 | In this module, coroutines are defined as "callchain + lexical variables + |
52 | In this module, coroutines are defined as "callchain + lexical variables + |
36 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
53 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
37 | its own set of lexicals and its own set of perls most important global |
54 | its own set of lexicals and its own set of perls most important global |
38 | variables. |
55 | variables (see L<Coro::State> for more configuration). |
39 | |
56 | |
40 | =cut |
57 | =cut |
41 | |
58 | |
42 | package Coro; |
59 | package Coro; |
43 | |
60 | |
44 | use strict; |
61 | use strict qw(vars subs); |
45 | no warnings "uninitialized"; |
62 | no warnings "uninitialized"; |
46 | |
63 | |
47 | use Coro::State; |
64 | use Coro::State; |
48 | |
65 | |
49 | use base qw(Coro::State Exporter); |
66 | use base qw(Coro::State Exporter); |
50 | |
67 | |
51 | our $idle; # idle handler |
68 | our $idle; # idle handler |
52 | our $main; # main coroutine |
69 | our $main; # main coroutine |
53 | our $current; # current coroutine |
70 | our $current; # current coroutine |
54 | |
71 | |
55 | our $VERSION = '4.01'; |
72 | our $VERSION = 5.0; |
56 | |
73 | |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
74 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
58 | our %EXPORT_TAGS = ( |
75 | our %EXPORT_TAGS = ( |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
76 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
60 | ); |
77 | ); |
61 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
78 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
62 | |
79 | |
63 | { |
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64 | my @async; |
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65 | my $init; |
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66 | |
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67 | # this way of handling attributes simply is NOT scalable ;() |
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68 | sub import { |
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69 | no strict 'refs'; |
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70 | |
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71 | Coro->export_to_level (1, @_); |
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72 | |
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73 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
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74 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
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75 | my ($package, $ref) = (shift, shift); |
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76 | my @attrs; |
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77 | for (@_) { |
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78 | if ($_ eq "Coro") { |
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79 | push @async, $ref; |
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80 | unless ($init++) { |
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81 | eval q{ |
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82 | sub INIT { |
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83 | &async(pop @async) while @async; |
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84 | } |
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85 | }; |
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86 | } |
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87 | } else { |
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88 | push @attrs, $_; |
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89 | } |
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90 | } |
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91 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
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92 | }; |
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93 | } |
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94 | |
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95 | } |
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96 | |
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97 | =over 4 |
80 | =over 4 |
98 | |
81 | |
99 | =item $main |
82 | =item $Coro::main |
100 | |
83 | |
101 | This coroutine represents the main program. |
84 | This variable stores the coroutine object that represents the main |
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85 | program. While you cna C<ready> it and do most other things you can do to |
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86 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
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87 | whether you are running in the main program or not. |
102 | |
88 | |
103 | =cut |
89 | =cut |
104 | |
90 | |
105 | $main = new Coro; |
91 | $main = new Coro; |
106 | |
92 | |
107 | =item $current (or as function: current) |
93 | =item $Coro::current |
108 | |
94 | |
109 | The current coroutine (the last coroutine switched to). The initial value |
95 | The coroutine object representing the current coroutine (the last |
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96 | coroutine that the Coro scheduler switched to). The initial value is |
110 | is C<$main> (of course). |
97 | C<$main> (of course). |
111 | |
98 | |
112 | This variable is B<strictly> I<read-only>. It is provided for performance |
99 | This variable is B<strictly> I<read-only>. You can take copies of the |
113 | reasons. If performance is not essential you are encouraged to use the |
100 | value stored in it and use it as any other coroutine object, but you must |
114 | C<Coro::current> function instead. |
101 | not otherwise modify the variable itself. |
115 | |
102 | |
116 | =cut |
103 | =cut |
117 | |
104 | |
118 | $main->{desc} = "[main::]"; |
105 | $main->{desc} = "[main::]"; |
119 | |
106 | |
… | |
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121 | $main->{_specific} = $current->{_specific} |
108 | $main->{_specific} = $current->{_specific} |
122 | if $current; |
109 | if $current; |
123 | |
110 | |
124 | _set_current $main; |
111 | _set_current $main; |
125 | |
112 | |
126 | sub current() { $current } |
113 | sub current() { $current } # [DEPRECATED] |
127 | |
114 | |
128 | =item $idle |
115 | =item $Coro::idle |
129 | |
116 | |
130 | A callback that is called whenever the scheduler finds no ready coroutines |
117 | This variable is mainly useful to integrate Coro into event loops. It is |
131 | to run. The default implementation prints "FATAL: deadlock detected" and |
118 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
132 | exits, because the program has no other way to continue. |
119 | pretty low-level functionality. |
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120 | |
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121 | This variable stores a callback that is called whenever the scheduler |
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122 | finds no ready coroutines to run. The default implementation prints |
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123 | "FATAL: deadlock detected" and exits, because the program has no other way |
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124 | to continue. |
133 | |
125 | |
134 | This hook is overwritten by modules such as C<Coro::Timer> and |
126 | This hook is overwritten by modules such as C<Coro::Timer> and |
135 | C<Coro::Event> to wait on an external event that hopefully wake up a |
127 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
136 | coroutine so the scheduler can run it. |
128 | coroutine so the scheduler can run it. |
137 | |
129 | |
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130 | Note that the callback I<must not>, under any circumstances, block |
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131 | the current coroutine. Normally, this is achieved by having an "idle |
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132 | coroutine" that calls the event loop and then blocks again, and then |
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133 | readying that coroutine in the idle handler. |
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134 | |
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135 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
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136 | technique. |
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137 | |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
139 | handlers), then it must be prepared to be called recursively. |
139 | handlers), then it must be prepared to be called recursively itself. |
140 | |
140 | |
141 | =cut |
141 | =cut |
142 | |
142 | |
143 | $idle = sub { |
143 | $idle = sub { |
144 | require Carp; |
144 | require Carp; |
… | |
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152 | $self->_destroy |
152 | $self->_destroy |
153 | or return; |
153 | or return; |
154 | |
154 | |
155 | # call all destruction callbacks |
155 | # call all destruction callbacks |
156 | $_->(@{$self->{_status}}) |
156 | $_->(@{$self->{_status}}) |
157 | for @{(delete $self->{_on_destroy}) || []}; |
157 | for @{ delete $self->{_on_destroy} || [] }; |
158 | } |
158 | } |
159 | |
159 | |
160 | # this coroutine is necessary because a coroutine |
160 | # this coroutine is necessary because a coroutine |
161 | # cannot destroy itself. |
161 | # cannot destroy itself. |
162 | my @destroy; |
162 | my @destroy; |
… | |
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168 | while @destroy; |
168 | while @destroy; |
169 | |
169 | |
170 | &schedule; |
170 | &schedule; |
171 | } |
171 | } |
172 | }; |
172 | }; |
173 | $manager->desc ("[coro manager]"); |
173 | $manager->{desc} = "[coro manager]"; |
174 | $manager->prio (PRIO_MAX); |
174 | $manager->prio (PRIO_MAX); |
175 | |
175 | |
176 | # static methods. not really. |
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177 | |
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178 | =back |
176 | =back |
179 | |
177 | |
180 | =head2 STATIC METHODS |
178 | =head2 SIMPLE COROUTINE CREATION |
181 | |
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182 | Static methods are actually functions that operate on the current coroutine only. |
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183 | |
179 | |
184 | =over 4 |
180 | =over 4 |
185 | |
181 | |
186 | =item async { ... } [@args...] |
182 | =item async { ... } [@args...] |
187 | |
183 | |
188 | Create a new asynchronous coroutine and return it's coroutine object |
184 | Create a new coroutine and return it's coroutine object (usually |
189 | (usually unused). When the sub returns the new coroutine is automatically |
185 | unused). The coroutine will be put into the ready queue, so |
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186 | it will start running automatically on the next scheduler run. |
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187 | |
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188 | The first argument is a codeblock/closure that should be executed in the |
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189 | coroutine. When it returns argument returns the coroutine is automatically |
190 | terminated. |
190 | terminated. |
191 | |
191 | |
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192 | The remaining arguments are passed as arguments to the closure. |
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193 | |
192 | See the C<Coro::State::new> constructor for info about the coroutine |
194 | See the C<Coro::State::new> constructor for info about the coroutine |
193 | environment. |
195 | environment in which coroutines are executed. |
194 | |
196 | |
195 | Calling C<exit> in a coroutine will do the same as calling exit outside |
197 | Calling C<exit> in a coroutine will do the same as calling exit outside |
196 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
198 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
197 | just as it would in the main program. |
199 | just as it would in the main program. |
198 | |
200 | |
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201 | If you do not want that, you can provide a default C<die> handler, or |
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202 | simply avoid dieing (by use of C<eval>). |
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203 | |
199 | # create a new coroutine that just prints its arguments |
204 | Example: Create a new coroutine that just prints its arguments. |
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205 | |
200 | async { |
206 | async { |
201 | print "@_\n"; |
207 | print "@_\n"; |
202 | } 1,2,3,4; |
208 | } 1,2,3,4; |
203 | |
209 | |
204 | =cut |
210 | =cut |
… | |
… | |
210 | } |
216 | } |
211 | |
217 | |
212 | =item async_pool { ... } [@args...] |
218 | =item async_pool { ... } [@args...] |
213 | |
219 | |
214 | Similar to C<async>, but uses a coroutine pool, so you should not call |
220 | Similar to C<async>, but uses a coroutine pool, so you should not call |
215 | terminate or join (although you are allowed to), and you get a coroutine |
221 | terminate or join on it (although you are allowed to), and you get a |
216 | that might have executed other code already (which can be good or bad :). |
222 | coroutine that might have executed other code already (which can be good |
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223 | or bad :). |
217 | |
224 | |
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225 | On the plus side, this function is faster than creating (and destroying) |
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226 | a completly new coroutine, so if you need a lot of generic coroutines in |
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227 | quick successsion, use C<async_pool>, not C<async>. |
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228 | |
218 | Also, the block is executed in an C<eval> context and a warning will be |
229 | The code block is executed in an C<eval> context and a warning will be |
219 | issued in case of an exception instead of terminating the program, as |
230 | issued in case of an exception instead of terminating the program, as |
220 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
231 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
221 | will not work in the expected way, unless you call terminate or cancel, |
232 | will not work in the expected way, unless you call terminate or cancel, |
222 | which somehow defeats the purpose of pooling. |
233 | which somehow defeats the purpose of pooling (but is fine in the |
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234 | exceptional case). |
223 | |
235 | |
224 | The priority will be reset to C<0> after each job, tracing will be |
236 | The priority will be reset to C<0> after each run, tracing will be |
225 | disabled, the description will be reset and the default output filehandle |
237 | disabled, the description will be reset and the default output filehandle |
226 | gets restored, so you can change alkl these. Otherwise the coroutine will |
238 | gets restored, so you can change all these. Otherwise the coroutine will |
227 | be re-used "as-is": most notably if you change other per-coroutine global |
239 | be re-used "as-is": most notably if you change other per-coroutine global |
228 | stuff such as C<$/> you need to revert that change, which is most simply |
240 | stuff such as C<$/> you I<must needs> revert that change, which is most |
229 | done by using local as in C< local $/ >. |
241 | simply done by using local as in: C<< local $/ >>. |
230 | |
242 | |
231 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
243 | The idle pool size is limited to C<8> idle coroutines (this can be |
232 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
244 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
233 | required. |
245 | coros as required. |
234 | |
246 | |
235 | If you are concerned about pooled coroutines growing a lot because a |
247 | If you are concerned about pooled coroutines growing a lot because a |
236 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
248 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
237 | { terminate }> once per second or so to slowly replenish the pool. In |
249 | { terminate }> once per second or so to slowly replenish the pool. In |
238 | addition to that, when the stacks used by a handler grows larger than 16kb |
250 | addition to that, when the stacks used by a handler grows larger than 16kb |
239 | (adjustable with $Coro::POOL_RSS) it will also exit. |
251 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
240 | |
252 | |
241 | =cut |
253 | =cut |
242 | |
254 | |
243 | our $POOL_SIZE = 8; |
255 | our $POOL_SIZE = 8; |
244 | our $POOL_RSS = 16 * 1024; |
256 | our $POOL_RSS = 16 * 1024; |
… | |
… | |
255 | _pool_2 $cb; |
267 | _pool_2 $cb; |
256 | &schedule; |
268 | &schedule; |
257 | } |
269 | } |
258 | }; |
270 | }; |
259 | |
271 | |
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272 | if ($@) { |
260 | last if $@ eq "\3terminate\2\n"; |
273 | last if $@ eq "\3async_pool terminate\2\n"; |
261 | warn $@ if $@; |
274 | warn $@; |
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275 | } |
262 | } |
276 | } |
263 | } |
277 | } |
264 | |
278 | |
265 | sub async_pool(&@) { |
279 | sub async_pool(&@) { |
266 | # this is also inlined into the unlock_scheduler |
280 | # this is also inlined into the unlock_scheduler |
… | |
… | |
270 | $coro->ready; |
284 | $coro->ready; |
271 | |
285 | |
272 | $coro |
286 | $coro |
273 | } |
287 | } |
274 | |
288 | |
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289 | =back |
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290 | |
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291 | =head2 STATIC METHODS |
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292 | |
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293 | Static methods are actually functions that operate on the current coroutine. |
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294 | |
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295 | =over 4 |
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296 | |
275 | =item schedule |
297 | =item schedule |
276 | |
298 | |
277 | Calls the scheduler. Please note that the current coroutine will not be put |
299 | Calls the scheduler. The scheduler will find the next coroutine that is |
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300 | to be run from the ready queue and switches to it. The next coroutine |
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301 | to be run is simply the one with the highest priority that is longest |
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302 | in its ready queue. If there is no coroutine ready, it will clal the |
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303 | C<$Coro::idle> hook. |
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304 | |
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305 | Please note that the current coroutine will I<not> be put into the ready |
278 | into the ready queue, so calling this function usually means you will |
306 | queue, so calling this function usually means you will never be called |
279 | never be called again unless something else (e.g. an event handler) calls |
307 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
280 | ready. |
308 | thus waking you up. |
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309 | |
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310 | This makes C<schedule> I<the> generic method to use to block the current |
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311 | coroutine and wait for events: first you remember the current coroutine in |
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312 | a variable, then arrange for some callback of yours to call C<< ->ready |
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313 | >> on that once some event happens, and last you call C<schedule> to put |
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314 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
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315 | so you need to check whether the event indeed happened, e.g. by storing the |
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316 | status in a variable. |
281 | |
317 | |
282 | The canonical way to wait on external events is this: |
318 | The canonical way to wait on external events is this: |
283 | |
319 | |
284 | { |
320 | { |
285 | # remember current coroutine |
321 | # remember current coroutine |
… | |
… | |
298 | Coro::schedule while $current; |
334 | Coro::schedule while $current; |
299 | } |
335 | } |
300 | |
336 | |
301 | =item cede |
337 | =item cede |
302 | |
338 | |
303 | "Cede" to other coroutines. This function puts the current coroutine into the |
339 | "Cede" to other coroutines. This function puts the current coroutine into |
304 | ready queue and calls C<schedule>, which has the effect of giving up the |
340 | the ready queue and calls C<schedule>, which has the effect of giving |
305 | current "timeslice" to other coroutines of the same or higher priority. |
341 | up the current "timeslice" to other coroutines of the same or higher |
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342 | priority. Once your coroutine gets its turn again it will automatically be |
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343 | resumed. |
306 | |
344 | |
307 | Returns true if at least one coroutine switch has happened. |
345 | This function is often called C<yield> in other languages. |
308 | |
346 | |
309 | =item Coro::cede_notself |
347 | =item Coro::cede_notself |
310 | |
348 | |
311 | Works like cede, but is not exported by default and will cede to any |
349 | Works like cede, but is not exported by default and will cede to I<any> |
312 | coroutine, regardless of priority, once. |
350 | coroutine, regardless of priority. This is useful sometimes to ensure |
313 | |
351 | progress is made. |
314 | Returns true if at least one coroutine switch has happened. |
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315 | |
352 | |
316 | =item terminate [arg...] |
353 | =item terminate [arg...] |
317 | |
354 | |
318 | Terminates the current coroutine with the given status values (see L<cancel>). |
355 | Terminates the current coroutine with the given status values (see L<cancel>). |
319 | |
356 | |
320 | =item killall |
357 | =item killall |
321 | |
358 | |
322 | Kills/terminates/cancels all coroutines except the currently running |
359 | Kills/terminates/cancels all coroutines except the currently running |
323 | one. This is useful after a fork, either in the child or the parent, as |
360 | one. This is useful after a fork, either in the child or the parent, as |
324 | usually only one of them should inherit the running coroutines. |
361 | usually only one of them should inherit the running coroutines. |
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362 | |
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363 | Note that while this will try to free some of the main programs resources, |
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364 | you cannot free all of them, so if a coroutine that is not the main |
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365 | program calls this function, there will be some one-time resource leak. |
325 | |
366 | |
326 | =cut |
367 | =cut |
327 | |
368 | |
328 | sub terminate { |
369 | sub terminate { |
329 | $current->cancel (@_); |
370 | $current->cancel (@_); |
… | |
… | |
336 | } |
377 | } |
337 | } |
378 | } |
338 | |
379 | |
339 | =back |
380 | =back |
340 | |
381 | |
341 | # dynamic methods |
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342 | |
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343 | =head2 COROUTINE METHODS |
382 | =head2 COROUTINE METHODS |
344 | |
383 | |
345 | These are the methods you can call on coroutine objects. |
384 | These are the methods you can call on coroutine objects (or to create |
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385 | them). |
346 | |
386 | |
347 | =over 4 |
387 | =over 4 |
348 | |
388 | |
349 | =item new Coro \&sub [, @args...] |
389 | =item new Coro \&sub [, @args...] |
350 | |
390 | |
351 | Create a new coroutine and return it. When the sub returns the coroutine |
391 | Create a new coroutine and return it. When the sub returns, the coroutine |
352 | automatically terminates as if C<terminate> with the returned values were |
392 | automatically terminates as if C<terminate> with the returned values were |
353 | called. To make the coroutine run you must first put it into the ready queue |
393 | called. To make the coroutine run you must first put it into the ready |
354 | by calling the ready method. |
394 | queue by calling the ready method. |
355 | |
395 | |
356 | See C<async> and C<Coro::State::new> for additional info about the |
396 | See C<async> and C<Coro::State::new> for additional info about the |
357 | coroutine environment. |
397 | coroutine environment. |
358 | |
398 | |
359 | =cut |
399 | =cut |
… | |
… | |
368 | $class->SUPER::new (\&_run_coro, @_) |
408 | $class->SUPER::new (\&_run_coro, @_) |
369 | } |
409 | } |
370 | |
410 | |
371 | =item $success = $coroutine->ready |
411 | =item $success = $coroutine->ready |
372 | |
412 | |
373 | Put the given coroutine into the ready queue (according to it's priority) |
413 | Put the given coroutine into the end of its ready queue (there is one |
374 | and return true. If the coroutine is already in the ready queue, do nothing |
414 | queue for each priority) and return true. If the coroutine is already in |
375 | and return false. |
415 | the ready queue, do nothing and return false. |
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416 | |
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417 | This ensures that the scheduler will resume this coroutine automatically |
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418 | once all the coroutines of higher priority and all coroutines of the same |
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419 | priority that were put into the ready queue earlier have been resumed. |
376 | |
420 | |
377 | =item $is_ready = $coroutine->is_ready |
421 | =item $is_ready = $coroutine->is_ready |
378 | |
422 | |
379 | Return wether the coroutine is currently the ready queue or not, |
423 | Return whether the coroutine is currently the ready queue or not, |
380 | |
424 | |
381 | =item $coroutine->cancel (arg...) |
425 | =item $coroutine->cancel (arg...) |
382 | |
426 | |
383 | Terminates the given coroutine and makes it return the given arguments as |
427 | Terminates the given coroutine and makes it return the given arguments as |
384 | status (default: the empty list). Never returns if the coroutine is the |
428 | status (default: the empty list). Never returns if the coroutine is the |
… | |
… | |
397 | } else { |
441 | } else { |
398 | $self->_cancel; |
442 | $self->_cancel; |
399 | } |
443 | } |
400 | } |
444 | } |
401 | |
445 | |
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446 | =item $coroutine->throw ([$scalar]) |
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447 | |
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448 | If C<$throw> is specified and defined, it will be thrown as an exception |
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449 | inside the coroutine at the next convenient point in time (usually after |
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450 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
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451 | exception object. |
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452 | |
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453 | The exception object will be thrown "as is" with the specified scalar in |
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454 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
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455 | (unlike with C<die>). |
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456 | |
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457 | This can be used as a softer means than C<cancel> to ask a coroutine to |
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458 | end itself, although there is no guarantee that the exception will lead to |
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459 | termination, and if the exception isn't caught it might well end the whole |
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460 | program. |
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461 | |
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462 | You might also think of C<throw> as being the moral equivalent of |
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463 | C<kill>ing a coroutine with a signal (in this case, a scalar). |
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464 | |
402 | =item $coroutine->join |
465 | =item $coroutine->join |
403 | |
466 | |
404 | Wait until the coroutine terminates and return any values given to the |
467 | Wait until the coroutine terminates and return any values given to the |
405 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
468 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
406 | from multiple coroutines. |
469 | from multiple coroutines, and all will be resumed and given the status |
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470 | return once the C<$coroutine> terminates. |
407 | |
471 | |
408 | =cut |
472 | =cut |
409 | |
473 | |
410 | sub join { |
474 | sub join { |
411 | my $self = shift; |
475 | my $self = shift; |
… | |
… | |
426 | |
490 | |
427 | =item $coroutine->on_destroy (\&cb) |
491 | =item $coroutine->on_destroy (\&cb) |
428 | |
492 | |
429 | Registers a callback that is called when this coroutine gets destroyed, |
493 | Registers a callback that is called when this coroutine gets destroyed, |
430 | but before it is joined. The callback gets passed the terminate arguments, |
494 | but before it is joined. The callback gets passed the terminate arguments, |
431 | if any. |
495 | if any, and I<must not> die, under any circumstances. |
432 | |
496 | |
433 | =cut |
497 | =cut |
434 | |
498 | |
435 | sub on_destroy { |
499 | sub on_destroy { |
436 | my ($self, $cb) = @_; |
500 | my ($self, $cb) = @_; |
… | |
… | |
466 | higher values mean lower priority, just as in unix). |
530 | higher values mean lower priority, just as in unix). |
467 | |
531 | |
468 | =item $olddesc = $coroutine->desc ($newdesc) |
532 | =item $olddesc = $coroutine->desc ($newdesc) |
469 | |
533 | |
470 | Sets (or gets in case the argument is missing) the description for this |
534 | Sets (or gets in case the argument is missing) the description for this |
471 | coroutine. This is just a free-form string you can associate with a coroutine. |
535 | coroutine. This is just a free-form string you can associate with a |
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536 | coroutine. |
472 | |
537 | |
473 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
538 | This method simply sets the C<< $coroutine->{desc} >> member to the given |
474 | can modify this member directly if you wish. |
539 | string. You can modify this member directly if you wish. |
475 | |
540 | |
476 | =cut |
541 | =cut |
477 | |
542 | |
478 | sub desc { |
543 | sub desc { |
479 | my $old = $_[0]{desc}; |
544 | my $old = $_[0]{desc}; |
… | |
… | |
488 | =over 4 |
553 | =over 4 |
489 | |
554 | |
490 | =item Coro::nready |
555 | =item Coro::nready |
491 | |
556 | |
492 | Returns the number of coroutines that are currently in the ready state, |
557 | Returns the number of coroutines that are currently in the ready state, |
493 | i.e. that can be switched to. The value C<0> means that the only runnable |
558 | i.e. that can be switched to by calling C<schedule> directory or |
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559 | indirectly. The value C<0> means that the only runnable coroutine is the |
494 | coroutine is the currently running one, so C<cede> would have no effect, |
560 | currently running one, so C<cede> would have no effect, and C<schedule> |
495 | and C<schedule> would cause a deadlock unless there is an idle handler |
561 | would cause a deadlock unless there is an idle handler that wakes up some |
496 | that wakes up some coroutines. |
562 | coroutines. |
497 | |
563 | |
498 | =item my $guard = Coro::guard { ... } |
564 | =item my $guard = Coro::guard { ... } |
499 | |
565 | |
500 | This creates and returns a guard object. Nothing happens until the object |
566 | This creates and returns a guard object. Nothing happens until the object |
501 | gets destroyed, in which case the codeblock given as argument will be |
567 | gets destroyed, in which case the codeblock given as argument will be |
… | |
… | |
530 | |
596 | |
531 | |
597 | |
532 | =item unblock_sub { ... } |
598 | =item unblock_sub { ... } |
533 | |
599 | |
534 | This utility function takes a BLOCK or code reference and "unblocks" it, |
600 | This utility function takes a BLOCK or code reference and "unblocks" it, |
535 | returning the new coderef. This means that the new coderef will return |
601 | returning a new coderef. Unblocking means that calling the new coderef |
536 | immediately without blocking, returning nothing, while the original code |
602 | will return immediately without blocking, returning nothing, while the |
537 | ref will be called (with parameters) from within its own coroutine. |
603 | original code ref will be called (with parameters) from within another |
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604 | coroutine. |
538 | |
605 | |
539 | The reason this function exists is that many event libraries (such as the |
606 | The reason this function exists is that many event libraries (such as the |
540 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
607 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
541 | of thread-safety). This means you must not block within event callbacks, |
608 | of thread-safety). This means you must not block within event callbacks, |
542 | otherwise you might suffer from crashes or worse. |
609 | otherwise you might suffer from crashes or worse. The only event library |
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610 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
543 | |
611 | |
544 | This function allows your callbacks to block by executing them in another |
612 | This function allows your callbacks to block by executing them in another |
545 | coroutine where it is safe to block. One example where blocking is handy |
613 | coroutine where it is safe to block. One example where blocking is handy |
546 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
614 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
547 | disk. |
615 | disk, for example. |
548 | |
616 | |
549 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
617 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
550 | creating event callbacks that want to block. |
618 | creating event callbacks that want to block. |
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619 | |
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620 | If your handler does not plan to block (e.g. simply sends a message to |
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621 | another coroutine, or puts some other coroutine into the ready queue), |
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622 | there is no reason to use C<unblock_sub>. |
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623 | |
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624 | Note that you also need to use C<unblock_sub> for any other callbacks that |
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625 | are indirectly executed by any C-based event loop. For example, when you |
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626 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
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627 | provides callbacks that are the result of some event callback, then you |
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628 | must not block either, or use C<unblock_sub>. |
551 | |
629 | |
552 | =cut |
630 | =cut |
553 | |
631 | |
554 | our @unblock_queue; |
632 | our @unblock_queue; |
555 | |
633 | |
… | |
… | |
568 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
646 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
569 | } |
647 | } |
570 | schedule; # sleep well |
648 | schedule; # sleep well |
571 | } |
649 | } |
572 | }; |
650 | }; |
573 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
651 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
574 | |
652 | |
575 | sub unblock_sub(&) { |
653 | sub unblock_sub(&) { |
576 | my $cb = shift; |
654 | my $cb = shift; |
577 | |
655 | |
578 | sub { |
656 | sub { |
… | |
… | |
587 | |
665 | |
588 | 1; |
666 | 1; |
589 | |
667 | |
590 | =head1 BUGS/LIMITATIONS |
668 | =head1 BUGS/LIMITATIONS |
591 | |
669 | |
592 | - you must make very sure that no coro is still active on global |
670 | =over 4 |
593 | destruction. very bad things might happen otherwise (usually segfaults). |
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594 | |
671 | |
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672 | =item perl process emulation ("threads") |
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673 | |
595 | - this module is not thread-safe. You should only ever use this module |
674 | This module is not perl-pseudo-thread-safe. You should only ever use this |
596 | from the same thread (this requirement might be loosened in the future |
675 | module from the same thread (this requirement might be removed in the |
597 | to allow per-thread schedulers, but Coro::State does not yet allow |
676 | future to allow per-thread schedulers, but Coro::State does not yet allow |
598 | this). |
677 | this). I recommend disabling thread support and using processes, as having |
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678 | the windows process emulation enabled under unix roughly halves perl |
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679 | performance, even when not used. |
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680 | |
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681 | =item coroutine switching not signal safe |
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682 | |
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683 | You must not switch to another coroutine from within a signal handler |
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684 | (only relevant with %SIG - most event libraries provide safe signals). |
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685 | |
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686 | That means you I<MUST NOT> call any fucntion that might "block" the |
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687 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
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688 | anything that calls those. Everything else, including calling C<ready>, |
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689 | works. |
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690 | |
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691 | =back |
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692 | |
599 | |
693 | |
600 | =head1 SEE ALSO |
694 | =head1 SEE ALSO |
601 | |
695 | |
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696 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
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697 | |
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698 | Debugging: L<Coro::Debug>. |
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699 | |
602 | Support/Utility: L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
700 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
603 | |
701 | |
604 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
702 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
605 | |
703 | |
606 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
704 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
607 | |
705 | |
608 | Embedding: L<Coro:MakeMaker> |
706 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
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707 | |
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708 | XS API: L<Coro::MakeMaker>. |
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709 | |
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710 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
609 | |
711 | |
610 | =head1 AUTHOR |
712 | =head1 AUTHOR |
611 | |
713 | |
612 | Marc Lehmann <schmorp@schmorp.de> |
714 | Marc Lehmann <schmorp@schmorp.de> |
613 | http://home.schmorp.de/ |
715 | http://home.schmorp.de/ |