1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | Coro - coroutine process abstraction |
3 | Coro - the only 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 | For a tutorial-style introduction, please read the L<Coro::Intro> |
32 | threads but don't (in general) run in parallel at the same time even |
32 | manpage. This manpage mainly contains reference information. |
33 | on SMP machines. The specific flavor of coroutine used in this module |
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34 | also guarantees you that it will not switch between coroutines unless |
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35 | necessary, at easily-identified points in your program, so locking and |
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36 | parallel access are rarely an issue, making coroutine programming much |
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37 | safer and easier than threads programming. |
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38 | |
33 | |
39 | Unlike a normal perl program, however, coroutines allow you to have |
34 | This module collection manages continuations in general, most often |
40 | multiple running interpreters that share data, which is especially useful |
35 | in the form of cooperative threads (also called coroutines in the |
41 | to code pseudo-parallel processes and for event-based programming, such as |
36 | documentation). They are similar to kernel threads but don't (in general) |
42 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
37 | run in parallel at the same time even on SMP machines. The specific flavor |
43 | learn more. |
38 | of thread offered by this module also guarantees you that it will not |
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39 | switch between threads unless necessary, at easily-identified points in |
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40 | your program, so locking and parallel access are rarely an issue, making |
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41 | thread programming much safer and easier than using other thread models. |
44 | |
42 | |
45 | Coroutines are also useful because Perl has no support for threads (the so |
43 | Unlike the so-called "Perl threads" (which are not actually real threads |
46 | called "threads" that perl offers are nothing more than the (bad) process |
44 | but only the windows process emulation ported to unix), Coro provides a |
47 | emulation coming from the Windows platform: On standard operating systems |
45 | full shared address space, which makes communication between threads |
48 | they serve no purpose whatsoever, except by making your programs slow and |
46 | very easy. And threads are fast, too: disabling the Windows process |
49 | making them use a lot of memory. Best disable them when building perl, or |
47 | emulation code in your perl and using Coro can easily result in a two to |
50 | aks your software vendor/distributor to do it for you). |
48 | four times speed increase for your programs. |
51 | |
49 | |
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50 | Coro achieves that by supporting multiple running interpreters that share |
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51 | data, which is especially useful to code pseudo-parallel processes and |
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52 | for event-based programming, such as multiple HTTP-GET requests running |
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53 | concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro |
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54 | into an event-based environment. |
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55 | |
52 | In this module, coroutines are defined as "callchain + lexical variables + |
56 | In this module, a thread is defined as "callchain + lexical variables + |
53 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
57 | @_ + $_ + $@ + $/ + C stack), that is, a thread has its own callchain, |
54 | its own set of lexicals and its own set of perls most important global |
58 | its own set of lexicals and its own set of perls most important global |
55 | variables (see L<Coro::State> for more configuration). |
59 | variables (see L<Coro::State> for more configuration and background info). |
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60 | |
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61 | See also the C<SEE ALSO> section at the end of this document - the Coro |
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62 | module family is quite large. |
56 | |
63 | |
57 | =cut |
64 | =cut |
58 | |
65 | |
59 | package Coro; |
66 | package Coro; |
60 | |
67 | |
61 | use strict qw(vars subs); |
68 | use strict qw(vars subs); |
62 | no warnings "uninitialized"; |
69 | no warnings "uninitialized"; |
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70 | |
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71 | use Guard (); |
63 | |
72 | |
64 | use Coro::State; |
73 | use Coro::State; |
65 | |
74 | |
66 | use base qw(Coro::State Exporter); |
75 | use base qw(Coro::State Exporter); |
67 | |
76 | |
68 | our $idle; # idle handler |
77 | our $idle; # idle handler |
69 | our $main; # main coroutine |
78 | our $main; # main coroutine |
70 | our $current; # current coroutine |
79 | our $current; # current coroutine |
71 | |
80 | |
72 | our $VERSION = 5.0; |
81 | our $VERSION = 5.13; |
73 | |
82 | |
74 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
83 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
75 | our %EXPORT_TAGS = ( |
84 | our %EXPORT_TAGS = ( |
76 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
85 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
77 | ); |
86 | ); |
78 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
87 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
79 | |
88 | |
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89 | =head1 GLOBAL VARIABLES |
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90 | |
80 | =over 4 |
91 | =over 4 |
81 | |
92 | |
82 | =item $Coro::main |
93 | =item $Coro::main |
83 | |
94 | |
84 | This variable stores the coroutine object that represents the main |
95 | This variable stores the coroutine object that represents the main |
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105 | sub current() { $current } # [DEPRECATED] |
116 | sub current() { $current } # [DEPRECATED] |
106 | |
117 | |
107 | =item $Coro::idle |
118 | =item $Coro::idle |
108 | |
119 | |
109 | This variable is mainly useful to integrate Coro into event loops. It is |
120 | This variable is mainly useful to integrate Coro into event loops. It is |
110 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
121 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
111 | pretty low-level functionality. |
122 | pretty low-level functionality. |
112 | |
123 | |
113 | This variable stores a callback that is called whenever the scheduler |
124 | This variable stores either a coroutine or a callback. |
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125 | |
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126 | If it is a callback, the it is called whenever the scheduler finds no |
114 | finds no ready coroutines to run. The default implementation prints |
127 | ready coroutines to run. The default implementation prints "FATAL: |
115 | "FATAL: deadlock detected" and exits, because the program has no other way |
128 | deadlock detected" and exits, because the program has no other way to |
116 | to continue. |
129 | continue. |
117 | |
130 | |
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131 | If it is a coroutine object, then this object will be readied (without |
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132 | invoking any ready hooks, however) when the scheduler finds no other ready |
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133 | coroutines to run. |
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134 | |
118 | This hook is overwritten by modules such as C<Coro::Timer> and |
135 | This hook is overwritten by modules such as C<Coro::EV> and |
119 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
136 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
120 | coroutine so the scheduler can run it. |
137 | coroutine so the scheduler can run it. |
121 | |
138 | |
122 | Note that the callback I<must not>, under any circumstances, block |
139 | Note that the callback I<must not>, under any circumstances, block |
123 | the current coroutine. Normally, this is achieved by having an "idle |
140 | the current coroutine. Normally, this is achieved by having an "idle |
124 | coroutine" that calls the event loop and then blocks again, and then |
141 | coroutine" that calls the event loop and then blocks again, and then |
125 | readying that coroutine in the idle handler. |
142 | readying that coroutine in the idle handler, or by simply placing the idle |
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143 | coroutine in this variable. |
126 | |
144 | |
127 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
145 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
128 | technique. |
146 | technique. |
129 | |
147 | |
130 | Please note that if your callback recursively invokes perl (e.g. for event |
148 | Please note that if your callback recursively invokes perl (e.g. for event |
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135 | $idle = sub { |
153 | $idle = sub { |
136 | require Carp; |
154 | require Carp; |
137 | Carp::croak ("FATAL: deadlock detected"); |
155 | Carp::croak ("FATAL: deadlock detected"); |
138 | }; |
156 | }; |
139 | |
157 | |
140 | sub _cancel { |
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141 | my ($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 |
158 | # this coroutine is necessary because a coroutine |
153 | # cannot destroy itself. |
159 | # cannot destroy itself. |
154 | my @destroy; |
160 | our @destroy; |
155 | my $manager; |
161 | our $manager; |
156 | |
162 | |
157 | $manager = new Coro sub { |
163 | $manager = new Coro sub { |
158 | while () { |
164 | while () { |
159 | (shift @destroy)->_cancel |
165 | Coro::_cancel shift @destroy |
160 | while @destroy; |
166 | while @destroy; |
161 | |
167 | |
162 | &schedule; |
168 | &schedule; |
163 | } |
169 | } |
164 | }; |
170 | }; |
165 | $manager->{desc} = "[coro manager]"; |
171 | $manager->{desc} = "[coro manager]"; |
166 | $manager->prio (PRIO_MAX); |
172 | $manager->prio (PRIO_MAX); |
167 | |
173 | |
168 | =back |
174 | =back |
169 | |
175 | |
170 | =head2 SIMPLE COROUTINE CREATION |
176 | =head1 SIMPLE COROUTINE CREATION |
171 | |
177 | |
172 | =over 4 |
178 | =over 4 |
173 | |
179 | |
174 | =item async { ... } [@args...] |
180 | =item async { ... } [@args...] |
175 | |
181 | |
176 | Create a new coroutine and return it's coroutine object (usually |
182 | Create a new coroutine and return its coroutine object (usually |
177 | unused). The coroutine will be put into the ready queue, so |
183 | unused). The coroutine will be put into the ready queue, so |
178 | it will start running automatically on the next scheduler run. |
184 | it will start running automatically on the next scheduler run. |
179 | |
185 | |
180 | The first argument is a codeblock/closure that should be executed in the |
186 | The first argument is a codeblock/closure that should be executed in the |
181 | coroutine. When it returns argument returns the coroutine is automatically |
187 | coroutine. When it returns argument returns the coroutine is automatically |
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212 | Similar to C<async>, but uses a coroutine pool, so you should not call |
218 | 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 |
219 | 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 |
220 | coroutine that might have executed other code already (which can be good |
215 | or bad :). |
221 | or bad :). |
216 | |
222 | |
217 | On the plus side, this function is faster than creating (and destroying) |
223 | 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 |
224 | destroying) a completely new coroutine, so if you need a lot of generic |
219 | quick successsion, use C<async_pool>, not C<async>. |
225 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
220 | |
226 | |
221 | The code block is executed in an C<eval> context and a warning will be |
227 | 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 |
228 | 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> |
229 | 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, |
230 | will not work in the expected way, unless you call terminate or cancel, |
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237 | coros as required. |
243 | coros as required. |
238 | |
244 | |
239 | If you are concerned about pooled coroutines growing a lot because a |
245 | 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 |
246 | 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 |
247 | { 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 |
248 | 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. |
249 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
244 | |
250 | |
245 | =cut |
251 | =cut |
246 | |
252 | |
247 | our $POOL_SIZE = 8; |
253 | our $POOL_SIZE = 8; |
248 | our $POOL_RSS = 16 * 1024; |
254 | our $POOL_RSS = 32 * 1024; |
249 | our @async_pool; |
255 | our @async_pool; |
250 | |
256 | |
251 | sub pool_handler { |
257 | sub pool_handler { |
252 | my $cb; |
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253 | |
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254 | while () { |
258 | while () { |
255 | eval { |
259 | eval { |
256 | while () { |
260 | &{&_pool_handler} while 1; |
257 | _pool_1 $cb; |
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258 | &$cb; |
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259 | _pool_2 $cb; |
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260 | &schedule; |
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261 | } |
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262 | }; |
261 | }; |
263 | |
262 | |
264 | if ($@) { |
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265 | last if $@ eq "\3async_pool terminate\2\n"; |
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266 | warn $@; |
263 | warn $@ if $@; |
267 | } |
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268 | } |
264 | } |
269 | } |
265 | } |
270 | |
266 | |
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 | } |
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280 | |
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281 | =back |
267 | =back |
282 | |
268 | |
283 | =head2 STATIC METHODS |
269 | =head1 STATIC METHODS |
284 | |
270 | |
285 | Static methods are actually functions that operate on the current coroutine. |
271 | Static methods are actually functions that implicitly operate on the |
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272 | current coroutine. |
286 | |
273 | |
287 | =over 4 |
274 | =over 4 |
288 | |
275 | |
289 | =item schedule |
276 | =item schedule |
290 | |
277 | |
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305 | >> on that once some event happens, and last you call C<schedule> to put |
292 | >> on that once some event happens, and last you call C<schedule> to put |
306 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
293 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
307 | so you need to check whether the event indeed happened, e.g. by storing the |
294 | so you need to check whether the event indeed happened, e.g. by storing the |
308 | status in a variable. |
295 | status in a variable. |
309 | |
296 | |
310 | The canonical way to wait on external events is this: |
297 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
311 | |
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312 | { |
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313 | # remember current coroutine |
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314 | my $current = $Coro::current; |
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315 | |
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316 | # register a hypothetical event handler |
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317 | on_event_invoke sub { |
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318 | # wake up sleeping coroutine |
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319 | $current->ready; |
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320 | undef $current; |
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321 | }; |
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322 | |
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323 | # call schedule until event occurred. |
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324 | # in case we are woken up for other reasons |
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325 | # (current still defined), loop. |
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326 | Coro::schedule while $current; |
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327 | } |
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328 | |
298 | |
329 | =item cede |
299 | =item cede |
330 | |
300 | |
331 | "Cede" to other coroutines. This function puts the current coroutine into |
301 | "Cede" to other coroutines. This function puts the current coroutine into |
332 | the ready queue and calls C<schedule>, which has the effect of giving |
302 | the ready queue and calls C<schedule>, which has the effect of giving |
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344 | |
314 | |
345 | =item terminate [arg...] |
315 | =item terminate [arg...] |
346 | |
316 | |
347 | Terminates the current coroutine with the given status values (see L<cancel>). |
317 | Terminates the current coroutine with the given status values (see L<cancel>). |
348 | |
318 | |
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319 | =item Coro::on_enter BLOCK, Coro::on_leave BLOCK |
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320 | |
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321 | These function install enter and leave winders in the current scope. The |
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322 | enter block will be executed when on_enter is called and whenever the |
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323 | current coroutine is re-entered by the scheduler, while the leave block is |
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324 | executed whenever the current coroutine is blocked by the scheduler, and |
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325 | also when the containing scope is exited (by whatever means, be it exit, |
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326 | die, last etc.). |
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327 | |
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328 | I<Neither invoking the scheduler, nor exceptions, are allowed within those |
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329 | BLOCKs>. That means: do not even think about calling C<die> without an |
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330 | eval, and do not even think of entering the scheduler in any way. |
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331 | |
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332 | Since both BLOCKs are tied to the current scope, they will automatically |
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333 | be removed when the current scope exits. |
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334 | |
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335 | These functions implement the same concept as C<dynamic-wind> in scheme |
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336 | does, and are useful when you want to localise some resource to a specific |
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337 | coroutine. |
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338 | |
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339 | They slow down coroutine switching considerably for coroutines that use |
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340 | them (But coroutine switching is still reasonably fast if the handlers are |
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341 | fast). |
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342 | |
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343 | These functions are best understood by an example: The following function |
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344 | will change the current timezone to "Antarctica/South_Pole", which |
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345 | requires a call to C<tzset>, but by using C<on_enter> and C<on_leave>, |
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346 | which remember/change the current timezone and restore the previous |
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347 | value, respectively, the timezone is only changes for the coroutine that |
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348 | installed those handlers. |
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349 | |
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350 | use POSIX qw(tzset); |
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351 | |
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352 | async { |
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353 | my $old_tz; # store outside TZ value here |
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354 | |
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355 | Coro::on_enter { |
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356 | $old_tz = $ENV{TZ}; # remember the old value |
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357 | |
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358 | $ENV{TZ} = "Antarctica/South_Pole"; |
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359 | tzset; # enable new value |
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360 | }; |
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361 | |
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362 | Coro::on_leave { |
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363 | $ENV{TZ} = $old_tz; |
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364 | tzset; # restore old value |
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365 | }; |
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366 | |
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367 | # at this place, the timezone is Antarctica/South_Pole, |
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368 | # without disturbing the TZ of any other coroutine. |
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369 | }; |
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370 | |
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371 | This can be used to localise about any resource (locale, uid, current |
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372 | working directory etc.) to a block, despite the existance of other |
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373 | coroutines. |
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374 | |
349 | =item killall |
375 | =item killall |
350 | |
376 | |
351 | Kills/terminates/cancels all coroutines except the currently running |
377 | Kills/terminates/cancels all coroutines except the currently running one. |
352 | one. This is useful after a fork, either in the child or the parent, as |
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353 | usually only one of them should inherit the running coroutines. |
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354 | |
378 | |
355 | Note that while this will try to free some of the main programs resources, |
379 | Note that while this will try to free some of the main interpreter |
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380 | resources if the calling coroutine isn't the main coroutine, but one |
356 | you cannot free all of them, so if a coroutine that is not the main |
381 | cannot free all of them, so if a coroutine that is not the main coroutine |
357 | program calls this function, there will be some one-time resource leak. |
382 | calls this function, there will be some one-time resource leak. |
358 | |
383 | |
359 | =cut |
384 | =cut |
360 | |
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361 | sub terminate { |
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362 | $current->cancel (@_); |
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363 | } |
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364 | |
385 | |
365 | sub killall { |
386 | sub killall { |
366 | for (Coro::State::list) { |
387 | for (Coro::State::list) { |
367 | $_->cancel |
388 | $_->cancel |
368 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
389 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
369 | } |
390 | } |
370 | } |
391 | } |
371 | |
392 | |
372 | =back |
393 | =back |
373 | |
394 | |
374 | =head2 COROUTINE METHODS |
395 | =head1 COROUTINE OBJECT METHODS |
375 | |
396 | |
376 | These are the methods you can call on coroutine objects (or to create |
397 | These are the methods you can call on coroutine objects (or to create |
377 | them). |
398 | them). |
378 | |
399 | |
379 | =over 4 |
400 | =over 4 |
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388 | See C<async> and C<Coro::State::new> for additional info about the |
409 | See C<async> and C<Coro::State::new> for additional info about the |
389 | coroutine environment. |
410 | coroutine environment. |
390 | |
411 | |
391 | =cut |
412 | =cut |
392 | |
413 | |
393 | sub _run_coro { |
414 | sub _coro_run { |
394 | terminate &{+shift}; |
415 | terminate &{+shift}; |
395 | } |
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396 | |
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397 | sub new { |
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398 | my $class = shift; |
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399 | |
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400 | $class->SUPER::new (\&_run_coro, @_) |
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401 | } |
416 | } |
402 | |
417 | |
403 | =item $success = $coroutine->ready |
418 | =item $success = $coroutine->ready |
404 | |
419 | |
405 | Put the given coroutine into the end of its ready queue (there is one |
420 | Put the given coroutine into the end of its ready queue (there is one |
… | |
… | |
422 | |
437 | |
423 | =cut |
438 | =cut |
424 | |
439 | |
425 | sub cancel { |
440 | sub cancel { |
426 | my $self = shift; |
441 | my $self = shift; |
427 | $self->{_status} = [@_]; |
|
|
428 | |
442 | |
429 | if ($current == $self) { |
443 | if ($current == $self) { |
430 | push @destroy, $self; |
444 | terminate @_; |
431 | $manager->ready; |
|
|
432 | &schedule while 1; |
|
|
433 | } else { |
445 | } else { |
|
|
446 | $self->{_status} = [@_]; |
434 | $self->_cancel; |
447 | $self->_cancel; |
435 | } |
448 | } |
436 | } |
449 | } |
|
|
450 | |
|
|
451 | =item $coroutine->schedule_to |
|
|
452 | |
|
|
453 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
|
|
454 | of continuing with the next coro from the ready queue, always switch to |
|
|
455 | the given coroutine object (regardless of priority etc.). The readyness |
|
|
456 | state of that coroutine isn't changed. |
|
|
457 | |
|
|
458 | This is an advanced method for special cases - I'd love to hear about any |
|
|
459 | uses for this one. |
|
|
460 | |
|
|
461 | =item $coroutine->cede_to |
|
|
462 | |
|
|
463 | Like C<schedule_to>, but puts the current coroutine into the ready |
|
|
464 | queue. This has the effect of temporarily switching to the given |
|
|
465 | coroutine, and continuing some time later. |
|
|
466 | |
|
|
467 | This is an advanced method for special cases - I'd love to hear about any |
|
|
468 | uses for this one. |
437 | |
469 | |
438 | =item $coroutine->throw ([$scalar]) |
470 | =item $coroutine->throw ([$scalar]) |
439 | |
471 | |
440 | If C<$throw> is specified and defined, it will be thrown as an exception |
472 | If C<$throw> is specified and defined, it will be thrown as an exception |
441 | inside the coroutine at the next convenient point in time. Otherwise |
473 | inside the coroutine at the next convenient point in time. Otherwise |
442 | clears the exception object. |
474 | clears the exception object. |
443 | |
475 | |
444 | Coro will check for the exception each time a schedule-like-function |
476 | Coro will check for the exception each time a schedule-like-function |
445 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
477 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
446 | >>, C<< Coro::Handle->readable >> and so on. Note that this means that |
478 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
447 | when a coroutine is acquiring a lock, it might only throw after it has |
479 | detect this case and return early in case an exception is pending. |
448 | sucessfully acquired it. |
|
|
449 | |
480 | |
450 | The exception object will be thrown "as is" with the specified scalar in |
481 | The exception object will be thrown "as is" with the specified scalar in |
451 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
482 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
452 | (unlike with C<die>). |
483 | (unlike with C<die>). |
453 | |
484 | |
… | |
… | |
541 | my $old = $_[0]{desc}; |
572 | my $old = $_[0]{desc}; |
542 | $_[0]{desc} = $_[1] if @_ > 1; |
573 | $_[0]{desc} = $_[1] if @_ > 1; |
543 | $old; |
574 | $old; |
544 | } |
575 | } |
545 | |
576 | |
|
|
577 | sub transfer { |
|
|
578 | require Carp; |
|
|
579 | Carp::croak ("You must not call ->transfer on Coro objects. Use Coro::State objects or the ->schedule_to method. Caught"); |
|
|
580 | } |
|
|
581 | |
546 | =back |
582 | =back |
547 | |
583 | |
548 | =head2 GLOBAL FUNCTIONS |
584 | =head1 GLOBAL FUNCTIONS |
549 | |
585 | |
550 | =over 4 |
586 | =over 4 |
551 | |
587 | |
552 | =item Coro::nready |
588 | =item Coro::nready |
553 | |
589 | |
… | |
… | |
558 | would cause a deadlock unless there is an idle handler that wakes up some |
594 | would cause a deadlock unless there is an idle handler that wakes up some |
559 | coroutines. |
595 | coroutines. |
560 | |
596 | |
561 | =item my $guard = Coro::guard { ... } |
597 | =item my $guard = Coro::guard { ... } |
562 | |
598 | |
563 | This creates and returns a guard object. Nothing happens until the object |
599 | This function still exists, but is deprecated. Please use the |
564 | gets destroyed, in which case the codeblock given as argument will be |
600 | C<Guard::guard> function instead. |
565 | executed. This is useful to free locks or other resources in case of a |
|
|
566 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
567 | guard block will be executed. The guard object supports only one method, |
|
|
568 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
|
569 | |
601 | |
570 | Example: set some flag and clear it again when the coroutine gets canceled |
|
|
571 | or the function returns: |
|
|
572 | |
|
|
573 | sub do_something { |
|
|
574 | my $guard = Coro::guard { $busy = 0 }; |
|
|
575 | $busy = 1; |
|
|
576 | |
|
|
577 | # do something that requires $busy to be true |
|
|
578 | } |
|
|
579 | |
|
|
580 | =cut |
602 | =cut |
581 | |
603 | |
582 | sub guard(&) { |
604 | BEGIN { *guard = \&Guard::guard } |
583 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
584 | } |
|
|
585 | |
|
|
586 | sub Coro::guard::cancel { |
|
|
587 | ${$_[0]} = sub { }; |
|
|
588 | } |
|
|
589 | |
|
|
590 | sub Coro::guard::DESTROY { |
|
|
591 | ${$_[0]}->(); |
|
|
592 | } |
|
|
593 | |
|
|
594 | |
605 | |
595 | =item unblock_sub { ... } |
606 | =item unblock_sub { ... } |
596 | |
607 | |
597 | This utility function takes a BLOCK or code reference and "unblocks" it, |
608 | This utility function takes a BLOCK or code reference and "unblocks" it, |
598 | returning a new coderef. Unblocking means that calling the new coderef |
609 | returning a new coderef. Unblocking means that calling the new coderef |
… | |
… | |
600 | original code ref will be called (with parameters) from within another |
611 | original code ref will be called (with parameters) from within another |
601 | coroutine. |
612 | coroutine. |
602 | |
613 | |
603 | The reason this function exists is that many event libraries (such as the |
614 | The reason this function exists is that many event libraries (such as the |
604 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
615 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
605 | of thread-safety). This means you must not block within event callbacks, |
616 | of reentrancy). This means you must not block within event callbacks, |
606 | otherwise you might suffer from crashes or worse. The only event library |
617 | otherwise you might suffer from crashes or worse. The only event library |
607 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
618 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
608 | |
619 | |
609 | This function allows your callbacks to block by executing them in another |
620 | This function allows your callbacks to block by executing them in another |
610 | coroutine where it is safe to block. One example where blocking is handy |
621 | coroutine where it is safe to block. One example where blocking is handy |
… | |
… | |
633 | # return immediately and can be reused) and because we cannot cede |
644 | # return immediately and can be reused) and because we cannot cede |
634 | # inside an event callback. |
645 | # inside an event callback. |
635 | our $unblock_scheduler = new Coro sub { |
646 | our $unblock_scheduler = new Coro sub { |
636 | while () { |
647 | while () { |
637 | while (my $cb = pop @unblock_queue) { |
648 | while (my $cb = pop @unblock_queue) { |
638 | # this is an inlined copy of async_pool |
649 | &async_pool (@$cb); |
639 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
640 | |
650 | |
641 | $coro->{_invoke} = $cb; |
|
|
642 | $coro->ready; |
|
|
643 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
651 | # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
652 | # as the chance is very high that the async_poll coro will be back |
|
|
653 | # in the idle state when cede returns |
|
|
654 | cede; |
644 | } |
655 | } |
645 | schedule; # sleep well |
656 | schedule; # sleep well |
646 | } |
657 | } |
647 | }; |
658 | }; |
648 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
659 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
… | |
… | |
654 | unshift @unblock_queue, [$cb, @_]; |
665 | unshift @unblock_queue, [$cb, @_]; |
655 | $unblock_scheduler->ready; |
666 | $unblock_scheduler->ready; |
656 | } |
667 | } |
657 | } |
668 | } |
658 | |
669 | |
|
|
670 | =item $cb = Coro::rouse_cb |
|
|
671 | |
|
|
672 | Create and return a "rouse callback". That's a code reference that, |
|
|
673 | when called, will remember a copy of its arguments and notify the owner |
|
|
674 | coroutine of the callback. |
|
|
675 | |
|
|
676 | See the next function. |
|
|
677 | |
|
|
678 | =item @args = Coro::rouse_wait [$cb] |
|
|
679 | |
|
|
680 | Wait for the specified rouse callback (or the last one that was created in |
|
|
681 | this coroutine). |
|
|
682 | |
|
|
683 | As soon as the callback is invoked (or when the callback was invoked |
|
|
684 | before C<rouse_wait>), it will return the arguments originally passed to |
|
|
685 | the rouse callback. |
|
|
686 | |
|
|
687 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
|
|
688 | |
659 | =back |
689 | =back |
660 | |
690 | |
661 | =cut |
691 | =cut |
662 | |
692 | |
663 | 1; |
693 | 1; |
|
|
694 | |
|
|
695 | =head1 HOW TO WAIT FOR A CALLBACK |
|
|
696 | |
|
|
697 | It is very common for a coroutine to wait for some callback to be |
|
|
698 | called. This occurs naturally when you use coroutines in an otherwise |
|
|
699 | event-based program, or when you use event-based libraries. |
|
|
700 | |
|
|
701 | These typically register a callback for some event, and call that callback |
|
|
702 | when the event occured. In a coroutine, however, you typically want to |
|
|
703 | just wait for the event, simplyifying things. |
|
|
704 | |
|
|
705 | For example C<< AnyEvent->child >> registers a callback to be called when |
|
|
706 | a specific child has exited: |
|
|
707 | |
|
|
708 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
|
|
709 | |
|
|
710 | But from withina coroutine, you often just want to write this: |
|
|
711 | |
|
|
712 | my $status = wait_for_child $pid; |
|
|
713 | |
|
|
714 | Coro offers two functions specifically designed to make this easy, |
|
|
715 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
|
|
716 | |
|
|
717 | The first function, C<rouse_cb>, generates and returns a callback that, |
|
|
718 | when invoked, will save its arguments and notify the coroutine that |
|
|
719 | created the callback. |
|
|
720 | |
|
|
721 | The second function, C<rouse_wait>, waits for the callback to be called |
|
|
722 | (by calling C<schedule> to go to sleep) and returns the arguments |
|
|
723 | originally passed to the callback. |
|
|
724 | |
|
|
725 | Using these functions, it becomes easy to write the C<wait_for_child> |
|
|
726 | function mentioned above: |
|
|
727 | |
|
|
728 | sub wait_for_child($) { |
|
|
729 | my ($pid) = @_; |
|
|
730 | |
|
|
731 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
|
|
732 | |
|
|
733 | my ($rpid, $rstatus) = Coro::rouse_wait; |
|
|
734 | $rstatus |
|
|
735 | } |
|
|
736 | |
|
|
737 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
|
|
738 | you can roll your own, using C<schedule>: |
|
|
739 | |
|
|
740 | sub wait_for_child($) { |
|
|
741 | my ($pid) = @_; |
|
|
742 | |
|
|
743 | # store the current coroutine in $current, |
|
|
744 | # and provide result variables for the closure passed to ->child |
|
|
745 | my $current = $Coro::current; |
|
|
746 | my ($done, $rstatus); |
|
|
747 | |
|
|
748 | # pass a closure to ->child |
|
|
749 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
|
|
750 | $rstatus = $_[1]; # remember rstatus |
|
|
751 | $done = 1; # mark $rstatus as valud |
|
|
752 | }); |
|
|
753 | |
|
|
754 | # wait until the closure has been called |
|
|
755 | schedule while !$done; |
|
|
756 | |
|
|
757 | $rstatus |
|
|
758 | } |
|
|
759 | |
664 | |
760 | |
665 | =head1 BUGS/LIMITATIONS |
761 | =head1 BUGS/LIMITATIONS |
666 | |
762 | |
667 | =over 4 |
763 | =over 4 |
668 | |
764 | |
… | |
… | |
674 | fix your libc and use a saner backend. |
770 | fix your libc and use a saner backend. |
675 | |
771 | |
676 | =item perl process emulation ("threads") |
772 | =item perl process emulation ("threads") |
677 | |
773 | |
678 | This module is not perl-pseudo-thread-safe. You should only ever use this |
774 | This module is not perl-pseudo-thread-safe. You should only ever use this |
679 | module from the same thread (this requirement might be removed in the |
775 | module from the first thread (this requirement might be removed in the |
680 | future to allow per-thread schedulers, but Coro::State does not yet allow |
776 | future to allow per-thread schedulers, but Coro::State does not yet allow |
681 | this). I recommend disabling thread support and using processes, as having |
777 | this). I recommend disabling thread support and using processes, as having |
682 | the windows process emulation enabled under unix roughly halves perl |
778 | the windows process emulation enabled under unix roughly halves perl |
683 | performance, even when not used. |
779 | performance, even when not used. |
684 | |
780 | |
… | |
… | |
701 | |
797 | |
702 | Debugging: L<Coro::Debug>. |
798 | Debugging: L<Coro::Debug>. |
703 | |
799 | |
704 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
800 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
705 | |
801 | |
706 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
802 | Locking and IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
|
|
803 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
707 | |
804 | |
708 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
805 | I/O and Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
709 | |
806 | |
710 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
807 | Compatibility with other modules: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
|
|
808 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
|
|
809 | L<Coro::Select>. |
711 | |
810 | |
712 | XS API: L<Coro::MakeMaker>. |
811 | XS API: L<Coro::MakeMaker>. |
713 | |
812 | |
714 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
813 | Low level Configuration, Thread Environment, Continuations: L<Coro::State>. |
715 | |
814 | |
716 | =head1 AUTHOR |
815 | =head1 AUTHOR |
717 | |
816 | |
718 | Marc Lehmann <schmorp@schmorp.de> |
817 | Marc Lehmann <schmorp@schmorp.de> |
719 | http://home.schmorp.de/ |
818 | http://home.schmorp.de/ |