1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | Coro - coroutine process abstraction |
3 | Coro - real threads in perl |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
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26 | $locked = 1; |
26 | $locked = 1; |
27 | $lock->up; |
27 | $lock->up; |
28 | |
28 | |
29 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
30 | |
30 | |
31 | This module collection manages coroutines. Coroutines are similar to |
31 | This module collection manages coroutines, that is, cooperative |
32 | threads but don't (in general) run in parallel at the same time even |
32 | threads. Coroutines are similar to kernel threads but don't (in general) |
33 | on SMP machines. The specific flavor of coroutine used in this module |
33 | run in parallel at the same time even on SMP machines. The specific flavor |
34 | also guarantees you that it will not switch between coroutines unless |
34 | of coroutine used in this module also guarantees you that it will not |
35 | necessary, at easily-identified points in your program, so locking and |
35 | switch between coroutines unless necessary, at easily-identified points |
36 | parallel access are rarely an issue, making coroutine programming much |
36 | in your program, so locking and parallel access are rarely an issue, |
37 | safer and easier than threads programming. |
37 | making coroutine programming much safer and easier than using other thread |
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38 | models. |
38 | |
39 | |
39 | Unlike a normal perl program, however, coroutines allow you to have |
40 | Unlike the so-called "Perl threads" (which are not actually real threads |
40 | multiple running interpreters that share data, which is especially useful |
41 | but only the windows process emulation ported to unix), Coro provides a |
41 | to code pseudo-parallel processes and for event-based programming, such as |
42 | full shared address space, which makes communication between coroutines |
42 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
43 | very easy. And coroutines are fast, too: disabling the Windows process |
43 | learn more. |
44 | emulation code in your perl and using Coro can easily result in a two to |
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45 | four times speed increase for your programs. |
44 | |
46 | |
45 | Coroutines are also useful because Perl has no support for threads (the so |
47 | Coro achieves that by supporting multiple running interpreters that share |
46 | called "threads" that perl offers are nothing more than the (bad) process |
48 | data, which is especially useful to code pseudo-parallel processes and |
47 | emulation coming from the Windows platform: On standard operating systems |
49 | for event-based programming, such as multiple HTTP-GET requests running |
48 | they serve no purpose whatsoever, except by making your programs slow and |
50 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
49 | making them use a lot of memory. Best disable them when building perl, or |
51 | into an event-based environment. |
50 | aks your software vendor/distributor to do it for you). |
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51 | |
52 | |
52 | In this module, coroutines are defined as "callchain + lexical variables + |
53 | In this module, a coroutines is defined as "callchain + lexical variables |
53 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
54 | + @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own |
54 | its own set of lexicals and its own set of perls most important global |
55 | callchain, its own set of lexicals and its own set of perls most important |
55 | variables (see L<Coro::State> for more configuration). |
56 | global variables (see L<Coro::State> for more configuration and background |
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57 | info). |
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58 | |
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59 | See also the C<SEE ALSO> section at the end of this document - the Coro |
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60 | module family is quite large. |
56 | |
61 | |
57 | =cut |
62 | =cut |
58 | |
63 | |
59 | package Coro; |
64 | package Coro; |
60 | |
65 | |
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67 | |
72 | |
68 | our $idle; # idle handler |
73 | our $idle; # idle handler |
69 | our $main; # main coroutine |
74 | our $main; # main coroutine |
70 | our $current; # current coroutine |
75 | our $current; # current coroutine |
71 | |
76 | |
72 | our $VERSION = 5.0; |
77 | our $VERSION = "5.0"; |
73 | |
78 | |
74 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
79 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
75 | our %EXPORT_TAGS = ( |
80 | our %EXPORT_TAGS = ( |
76 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
81 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
77 | ); |
82 | ); |
78 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
83 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
79 | |
84 | |
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85 | =head1 GLOBAL VARIABLES |
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86 | |
80 | =over 4 |
87 | =over 4 |
81 | |
88 | |
82 | =item $Coro::main |
89 | =item $Coro::main |
83 | |
90 | |
84 | This variable stores the coroutine object that represents the main |
91 | This variable stores the coroutine object that represents the main |
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135 | $idle = sub { |
142 | $idle = sub { |
136 | require Carp; |
143 | require Carp; |
137 | Carp::croak ("FATAL: deadlock detected"); |
144 | Carp::croak ("FATAL: deadlock detected"); |
138 | }; |
145 | }; |
139 | |
146 | |
140 | sub _cancel { |
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141 | my ($self) = @_; |
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142 | |
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143 | # free coroutine data and mark as destructed |
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144 | $self->_destroy |
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145 | or return; |
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146 | |
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147 | # call all destruction callbacks |
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148 | $_->(@{$self->{_status}}) |
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149 | for @{ delete $self->{_on_destroy} || [] }; |
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150 | } |
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151 | |
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152 | # this coroutine is necessary because a coroutine |
147 | # this coroutine is necessary because a coroutine |
153 | # cannot destroy itself. |
148 | # cannot destroy itself. |
154 | our @destroy; |
149 | our @destroy; |
155 | our $manager; |
150 | our $manager; |
156 | |
151 | |
157 | $manager = new Coro sub { |
152 | $manager = new Coro sub { |
158 | while () { |
153 | while () { |
159 | (shift @destroy)->_cancel |
154 | Coro::_cancel shift @destroy |
160 | while @destroy; |
155 | while @destroy; |
161 | |
156 | |
162 | &schedule; |
157 | &schedule; |
163 | } |
158 | } |
164 | }; |
159 | }; |
165 | $manager->{desc} = "[coro manager]"; |
160 | $manager->{desc} = "[coro manager]"; |
166 | $manager->prio (PRIO_MAX); |
161 | $manager->prio (PRIO_MAX); |
167 | |
162 | |
168 | =back |
163 | =back |
169 | |
164 | |
170 | =head2 SIMPLE COROUTINE CREATION |
165 | =head1 SIMPLE COROUTINE CREATION |
171 | |
166 | |
172 | =over 4 |
167 | =over 4 |
173 | |
168 | |
174 | =item async { ... } [@args...] |
169 | =item async { ... } [@args...] |
175 | |
170 | |
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212 | Similar to C<async>, but uses a coroutine pool, so you should not call |
207 | Similar to C<async>, but uses a coroutine pool, so you should not call |
213 | terminate or join on it (although you are allowed to), and you get a |
208 | terminate or join on it (although you are allowed to), and you get a |
214 | coroutine that might have executed other code already (which can be good |
209 | coroutine that might have executed other code already (which can be good |
215 | or bad :). |
210 | or bad :). |
216 | |
211 | |
217 | On the plus side, this function is faster than creating (and destroying) |
212 | On the plus side, this function is about twice as fast as creating (and |
218 | a completly new coroutine, so if you need a lot of generic coroutines in |
213 | destroying) a completely new coroutine, so if you need a lot of generic |
219 | quick successsion, use C<async_pool>, not C<async>. |
214 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
220 | |
215 | |
221 | The code block is executed in an C<eval> context and a warning will be |
216 | The code block is executed in an C<eval> context and a warning will be |
222 | issued in case of an exception instead of terminating the program, as |
217 | issued in case of an exception instead of terminating the program, as |
223 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
218 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
224 | will not work in the expected way, unless you call terminate or cancel, |
219 | will not work in the expected way, unless you call terminate or cancel, |
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237 | coros as required. |
232 | coros as required. |
238 | |
233 | |
239 | If you are concerned about pooled coroutines growing a lot because a |
234 | If you are concerned about pooled coroutines growing a lot because a |
240 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
235 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
241 | { terminate }> once per second or so to slowly replenish the pool. In |
236 | { terminate }> once per second or so to slowly replenish the pool. In |
242 | addition to that, when the stacks used by a handler grows larger than 16kb |
237 | addition to that, when the stacks used by a handler grows larger than 32kb |
243 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
238 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
244 | |
239 | |
245 | =cut |
240 | =cut |
246 | |
241 | |
247 | our $POOL_SIZE = 8; |
242 | our $POOL_SIZE = 8; |
248 | our $POOL_RSS = 16 * 1024; |
243 | our $POOL_RSS = 32 * 1024; |
249 | our @async_pool; |
244 | our @async_pool; |
250 | |
245 | |
251 | sub pool_handler { |
246 | sub pool_handler { |
252 | my $cb; |
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253 | |
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254 | while () { |
247 | while () { |
255 | eval { |
248 | eval { |
256 | while () { |
249 | &{&_pool_handler} while 1; |
257 | _pool_1 $cb; |
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258 | &$cb; |
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259 | _pool_2 $cb; |
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260 | &schedule; |
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261 | } |
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262 | }; |
250 | }; |
263 | |
251 | |
264 | if ($@) { |
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265 | last if $@ eq "\3async_pool terminate\2\n"; |
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266 | warn $@; |
252 | warn $@ if $@; |
267 | } |
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268 | } |
253 | } |
269 | } |
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270 | |
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271 | sub async_pool(&@) { |
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272 | # this is also inlined into the unblock_scheduler |
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273 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
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274 | |
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275 | $coro->{_invoke} = [@_]; |
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276 | $coro->ready; |
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277 | |
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278 | $coro |
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279 | } |
254 | } |
280 | |
255 | |
281 | =back |
256 | =back |
282 | |
257 | |
283 | =head2 STATIC METHODS |
258 | =head1 STATIC METHODS |
284 | |
259 | |
285 | Static methods are actually functions that operate on the current coroutine. |
260 | Static methods are actually functions that implicitly operate on the |
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261 | current coroutine. |
286 | |
262 | |
287 | =over 4 |
263 | =over 4 |
288 | |
264 | |
289 | =item schedule |
265 | =item schedule |
290 | |
266 | |
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339 | you cannot free all of them, so if a coroutine that is not the main |
315 | you cannot free all of them, so if a coroutine that is not the main |
340 | program calls this function, there will be some one-time resource leak. |
316 | program calls this function, there will be some one-time resource leak. |
341 | |
317 | |
342 | =cut |
318 | =cut |
343 | |
319 | |
344 | sub terminate { |
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345 | $current->{_status} = [@_]; |
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346 | push @destroy, $current; |
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347 | $manager->ready; |
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348 | do { &schedule } while 1; |
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349 | } |
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350 | |
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351 | sub killall { |
320 | sub killall { |
352 | for (Coro::State::list) { |
321 | for (Coro::State::list) { |
353 | $_->cancel |
322 | $_->cancel |
354 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
323 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
355 | } |
324 | } |
356 | } |
325 | } |
357 | |
326 | |
358 | =back |
327 | =back |
359 | |
328 | |
360 | =head2 COROUTINE METHODS |
329 | =head1 COROUTINE OBJECT METHODS |
361 | |
330 | |
362 | These are the methods you can call on coroutine objects (or to create |
331 | These are the methods you can call on coroutine objects (or to create |
363 | them). |
332 | them). |
364 | |
333 | |
365 | =over 4 |
334 | =over 4 |
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411 | $self->{_status} = [@_]; |
380 | $self->{_status} = [@_]; |
412 | $self->_cancel; |
381 | $self->_cancel; |
413 | } |
382 | } |
414 | } |
383 | } |
415 | |
384 | |
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385 | =item $coroutine->schedule_to |
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386 | |
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387 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
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388 | of continuing with the next coro from the ready queue, always switch to |
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389 | the given coroutine object (regardless of priority etc.). The readyness |
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390 | state of that coroutine isn't changed. |
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391 | |
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392 | This is an advanced method for special cases - I'd love to hear about any |
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393 | uses for this one. |
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394 | |
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395 | =item $coroutine->cede_to |
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396 | |
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397 | Like C<schedule_to>, but puts the current coroutine into the ready |
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398 | queue. This has the effect of temporarily switching to the given |
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399 | coroutine, and continuing some time later. |
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400 | |
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401 | This is an advanced method for special cases - I'd love to hear about any |
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402 | uses for this one. |
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403 | |
416 | =item $coroutine->throw ([$scalar]) |
404 | =item $coroutine->throw ([$scalar]) |
417 | |
405 | |
418 | If C<$throw> is specified and defined, it will be thrown as an exception |
406 | If C<$throw> is specified and defined, it will be thrown as an exception |
419 | inside the coroutine at the next convenient point in time. Otherwise |
407 | inside the coroutine at the next convenient point in time. Otherwise |
420 | clears the exception object. |
408 | clears the exception object. |
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518 | my $old = $_[0]{desc}; |
506 | my $old = $_[0]{desc}; |
519 | $_[0]{desc} = $_[1] if @_ > 1; |
507 | $_[0]{desc} = $_[1] if @_ > 1; |
520 | $old; |
508 | $old; |
521 | } |
509 | } |
522 | |
510 | |
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511 | sub transfer { |
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512 | require Carp; |
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513 | Carp::croak ("You must not call ->transfer on Coro objects. Use Coro::State objects or the ->schedule_to method. Caught"); |
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514 | } |
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515 | |
523 | =back |
516 | =back |
524 | |
517 | |
525 | =head2 GLOBAL FUNCTIONS |
518 | =head1 GLOBAL FUNCTIONS |
526 | |
519 | |
527 | =over 4 |
520 | =over 4 |
528 | |
521 | |
529 | =item Coro::nready |
522 | =item Coro::nready |
530 | |
523 | |
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610 | # return immediately and can be reused) and because we cannot cede |
603 | # return immediately and can be reused) and because we cannot cede |
611 | # inside an event callback. |
604 | # inside an event callback. |
612 | our $unblock_scheduler = new Coro sub { |
605 | our $unblock_scheduler = new Coro sub { |
613 | while () { |
606 | while () { |
614 | while (my $cb = pop @unblock_queue) { |
607 | while (my $cb = pop @unblock_queue) { |
615 | # this is an inlined copy of async_pool |
608 | &async_pool (@$cb); |
616 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
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617 | |
609 | |
618 | $coro->{_invoke} = $cb; |
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619 | $coro->ready; |
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620 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
610 | # for short-lived callbacks, this reduces pressure on the coro pool |
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611 | # as the chance is very high that the async_poll coro will be back |
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612 | # in the idle state when cede returns |
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613 | cede; |
621 | } |
614 | } |
622 | schedule; # sleep well |
615 | schedule; # sleep well |
623 | } |
616 | } |
624 | }; |
617 | }; |
625 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
618 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
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763 | |
756 | |
764 | Debugging: L<Coro::Debug>. |
757 | Debugging: L<Coro::Debug>. |
765 | |
758 | |
766 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
759 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
767 | |
760 | |
768 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
761 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
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762 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
769 | |
763 | |
770 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
764 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
771 | |
765 | |
772 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
766 | Compatibility: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
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767 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
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768 | L<Coro::Select>. |
773 | |
769 | |
774 | XS API: L<Coro::MakeMaker>. |
770 | XS API: L<Coro::MakeMaker>. |
775 | |
771 | |
776 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
772 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
777 | |
773 | |