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 | |
… | |
… | |
16 | cede; # yield to coroutine |
16 | cede; # yield to coroutine |
17 | print "3\n"; |
17 | print "3\n"; |
18 | cede; # and again |
18 | cede; # and again |
19 | |
19 | |
20 | # use locking |
20 | # use locking |
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21 | use Coro::Semaphore; |
21 | my $lock = new Coro::Semaphore; |
22 | my $lock = new Coro::Semaphore; |
22 | my $locked; |
23 | my $locked; |
23 | |
24 | |
24 | $lock->down; |
25 | $lock->down; |
25 | $locked = 1; |
26 | $locked = 1; |
26 | $lock->up; |
27 | $lock->up; |
27 | |
28 | |
28 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
29 | |
30 | |
30 | This module collection manages coroutines. Coroutines are similar to |
31 | For a tutorial-style introduction, please read the L<Coro::Intro> |
31 | threads but don't (in general) run in parallel at the same time even |
32 | manpage. This manpage mainly contains reference information. |
32 | on SMP machines. The specific flavor of coroutine used in this module |
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33 | also guarantees you that it will not switch between coroutines unless |
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34 | necessary, at easily-identified points in your program, so locking and |
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35 | parallel access are rarely an issue, making coroutine programming much |
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36 | safer and easier than threads programming. |
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37 | |
33 | |
38 | Unlike a normal perl program, however, coroutines allow you to have |
34 | This module collection manages continuations in general, most often |
39 | multiple running interpreters that share data, which is especially useful |
35 | in the form of cooperative threads (also called coroutines in the |
40 | 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) |
41 | 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 |
42 | 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. |
43 | |
42 | |
44 | 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 |
45 | 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 |
46 | emulation coming from the Windows platform: On standard operating systems |
45 | full shared address space, which makes communication between threads |
47 | they serve no purpose whatsoever, except by making your programs slow and |
46 | very easy. And threads are fast, too: disabling the Windows process |
48 | 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 |
49 | aks your software vendor/distributor to do it for you). |
48 | four times speed increase for your programs. |
50 | |
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 | |
51 | In this module, coroutines are defined as "callchain + lexical variables + |
56 | In this module, a thread is defined as "callchain + lexical variables + |
52 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
57 | @_ + $_ + $@ + $/ + C stack), that is, a thread has its own callchain, |
53 | 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 |
54 | 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. |
55 | |
63 | |
56 | =cut |
64 | =cut |
57 | |
65 | |
58 | package Coro; |
66 | package Coro; |
59 | |
67 | |
60 | use strict; |
68 | use strict qw(vars subs); |
61 | no warnings "uninitialized"; |
69 | no warnings "uninitialized"; |
62 | |
70 | |
63 | use Coro::State; |
71 | use Coro::State; |
64 | |
72 | |
65 | use base qw(Coro::State Exporter); |
73 | use base qw(Coro::State Exporter); |
66 | |
74 | |
67 | our $idle; # idle handler |
75 | our $idle; # idle handler |
68 | our $main; # main coroutine |
76 | our $main; # main coroutine |
69 | our $current; # current coroutine |
77 | our $current; # current coroutine |
70 | |
78 | |
71 | our $VERSION = '4.72'; |
79 | our $VERSION = 5.12; |
72 | |
80 | |
73 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
81 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
74 | our %EXPORT_TAGS = ( |
82 | our %EXPORT_TAGS = ( |
75 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
83 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
76 | ); |
84 | ); |
77 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
85 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
78 | |
86 | |
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87 | =head1 GLOBAL VARIABLES |
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88 | |
79 | =over 4 |
89 | =over 4 |
80 | |
90 | |
81 | =item $Coro::main |
91 | =item $Coro::main |
82 | |
92 | |
83 | This variable stores the coroutine object that represents the main |
93 | This variable stores the coroutine object that represents the main |
84 | program. While you cna C<ready> it and do most other things you can do to |
94 | program. While you cna C<ready> it and do most other things you can do to |
85 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
95 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
86 | wether you are running in the main program or not. |
96 | whether you are running in the main program or not. |
87 | |
97 | |
88 | =cut |
98 | =cut |
89 | |
99 | |
90 | $main = new Coro; |
100 | # $main is now being initialised by Coro::State |
91 | |
101 | |
92 | =item $Coro::current |
102 | =item $Coro::current |
93 | |
103 | |
94 | The coroutine object representing the current coroutine (the last |
104 | The coroutine object representing the current coroutine (the last |
95 | coroutine that the Coro scheduler switched to). The initial value is |
105 | coroutine that the Coro scheduler switched to). The initial value is |
96 | C<$main> (of course). |
106 | C<$Coro::main> (of course). |
97 | |
107 | |
98 | This variable is B<strictly> I<read-only>. You can take copies of the |
108 | This variable is B<strictly> I<read-only>. You can take copies of the |
99 | value stored in it and use it as any other coroutine object, but you must |
109 | value stored in it and use it as any other coroutine object, but you must |
100 | not otherwise modify the variable itself. |
110 | not otherwise modify the variable itself. |
101 | |
111 | |
102 | =cut |
112 | =cut |
103 | |
113 | |
104 | $main->{desc} = "[main::]"; |
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105 | |
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106 | # maybe some other module used Coro::Specific before... |
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107 | $main->{_specific} = $current->{_specific} |
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108 | if $current; |
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109 | |
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110 | _set_current $main; |
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111 | |
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112 | sub current() { $current } # [DEPRECATED] |
114 | sub current() { $current } # [DEPRECATED] |
113 | |
115 | |
114 | =item $Coro::idle |
116 | =item $Coro::idle |
115 | |
117 | |
116 | This variable is mainly useful to integrate Coro into event loops. It is |
118 | This variable is mainly useful to integrate Coro into event loops. It is |
117 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
119 | usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is |
118 | pretty low-level functionality. |
120 | pretty low-level functionality. |
119 | |
121 | |
120 | This variable stores a callback that is called whenever the scheduler |
122 | This variable stores either a coroutine or a callback. |
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123 | |
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124 | If it is a callback, the it is called whenever the scheduler finds no |
121 | finds no ready coroutines to run. The default implementation prints |
125 | ready coroutines to run. The default implementation prints "FATAL: |
122 | "FATAL: deadlock detected" and exits, because the program has no other way |
126 | deadlock detected" and exits, because the program has no other way to |
123 | to continue. |
127 | continue. |
124 | |
128 | |
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129 | If it is a coroutine object, then this object will be readied (without |
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130 | invoking any ready hooks, however) when the scheduler finds no other ready |
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131 | coroutines to run. |
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132 | |
125 | This hook is overwritten by modules such as C<Coro::Timer> and |
133 | This hook is overwritten by modules such as C<Coro::EV> and |
126 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
134 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
127 | coroutine so the scheduler can run it. |
135 | coroutine so the scheduler can run it. |
128 | |
136 | |
129 | Note that the callback I<must not>, under any circumstances, block |
137 | Note that the callback I<must not>, under any circumstances, block |
130 | the current coroutine. Normally, this is achieved by having an "idle |
138 | the current coroutine. Normally, this is achieved by having an "idle |
131 | coroutine" that calls the event loop and then blocks again, and then |
139 | coroutine" that calls the event loop and then blocks again, and then |
132 | readying that coroutine in the idle handler. |
140 | readying that coroutine in the idle handler, or by simply placing the idle |
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141 | coroutine in this variable. |
133 | |
142 | |
134 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
143 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
135 | technique. |
144 | technique. |
136 | |
145 | |
137 | Please note that if your callback recursively invokes perl (e.g. for event |
146 | Please note that if your callback recursively invokes perl (e.g. for event |
… | |
… | |
142 | $idle = sub { |
151 | $idle = sub { |
143 | require Carp; |
152 | require Carp; |
144 | Carp::croak ("FATAL: deadlock detected"); |
153 | Carp::croak ("FATAL: deadlock detected"); |
145 | }; |
154 | }; |
146 | |
155 | |
147 | sub _cancel { |
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148 | my ($self) = @_; |
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149 | |
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150 | # free coroutine data and mark as destructed |
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151 | $self->_destroy |
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152 | or return; |
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153 | |
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154 | # call all destruction callbacks |
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155 | $_->(@{$self->{_status}}) |
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156 | for @{(delete $self->{_on_destroy}) || []}; |
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157 | } |
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158 | |
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159 | # this coroutine is necessary because a coroutine |
156 | # this coroutine is necessary because a coroutine |
160 | # cannot destroy itself. |
157 | # cannot destroy itself. |
161 | my @destroy; |
158 | our @destroy; |
162 | my $manager; |
159 | our $manager; |
163 | |
160 | |
164 | $manager = new Coro sub { |
161 | $manager = new Coro sub { |
165 | while () { |
162 | while () { |
166 | (shift @destroy)->_cancel |
163 | Coro::_cancel shift @destroy |
167 | while @destroy; |
164 | while @destroy; |
168 | |
165 | |
169 | &schedule; |
166 | &schedule; |
170 | } |
167 | } |
171 | }; |
168 | }; |
172 | $manager->desc ("[coro manager]"); |
169 | $manager->{desc} = "[coro manager]"; |
173 | $manager->prio (PRIO_MAX); |
170 | $manager->prio (PRIO_MAX); |
174 | |
171 | |
175 | =back |
172 | =back |
176 | |
173 | |
177 | =head2 SIMPLE COROUTINE CREATION |
174 | =head1 SIMPLE COROUTINE CREATION |
178 | |
175 | |
179 | =over 4 |
176 | =over 4 |
180 | |
177 | |
181 | =item async { ... } [@args...] |
178 | =item async { ... } [@args...] |
182 | |
179 | |
183 | Create a new coroutine and return it's coroutine object (usually |
180 | Create a new coroutine and return its coroutine object (usually |
184 | unused). The coroutine will be put into the ready queue, so |
181 | unused). The coroutine will be put into the ready queue, so |
185 | it will start running automatically on the next scheduler run. |
182 | it will start running automatically on the next scheduler run. |
186 | |
183 | |
187 | The first argument is a codeblock/closure that should be executed in the |
184 | The first argument is a codeblock/closure that should be executed in the |
188 | coroutine. When it returns argument returns the coroutine is automatically |
185 | coroutine. When it returns argument returns the coroutine is automatically |
… | |
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219 | Similar to C<async>, but uses a coroutine pool, so you should not call |
216 | Similar to C<async>, but uses a coroutine pool, so you should not call |
220 | terminate or join on it (although you are allowed to), and you get a |
217 | terminate or join on it (although you are allowed to), and you get a |
221 | coroutine that might have executed other code already (which can be good |
218 | coroutine that might have executed other code already (which can be good |
222 | or bad :). |
219 | or bad :). |
223 | |
220 | |
224 | On the plus side, this function is faster than creating (and destroying) |
221 | On the plus side, this function is about twice as fast as creating (and |
225 | a completely new coroutine, so if you need a lot of generic coroutines in |
222 | destroying) a completely new coroutine, so if you need a lot of generic |
226 | quick successsion, use C<async_pool>, not C<async>. |
223 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
227 | |
224 | |
228 | The code block is executed in an C<eval> context and a warning will be |
225 | The code block is executed in an C<eval> context and a warning will be |
229 | issued in case of an exception instead of terminating the program, as |
226 | issued in case of an exception instead of terminating the program, as |
230 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
227 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
231 | will not work in the expected way, unless you call terminate or cancel, |
228 | will not work in the expected way, unless you call terminate or cancel, |
… | |
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234 | |
231 | |
235 | The priority will be reset to C<0> after each run, tracing will be |
232 | The priority will be reset to C<0> after each run, tracing will be |
236 | disabled, the description will be reset and the default output filehandle |
233 | disabled, the description will be reset and the default output filehandle |
237 | gets restored, so you can change all these. Otherwise the coroutine will |
234 | gets restored, so you can change all these. Otherwise the coroutine will |
238 | be re-used "as-is": most notably if you change other per-coroutine global |
235 | be re-used "as-is": most notably if you change other per-coroutine global |
239 | stuff such as C<$/> you I<must needs> to revert that change, which is most |
236 | stuff such as C<$/> you I<must needs> revert that change, which is most |
240 | simply done by using local as in: C< local $/ >. |
237 | simply done by using local as in: C<< local $/ >>. |
241 | |
238 | |
242 | The pool size is limited to C<8> idle coroutines (this can be adjusted by |
239 | The idle pool size is limited to C<8> idle coroutines (this can be |
243 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
240 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
244 | required. |
241 | coros as required. |
245 | |
242 | |
246 | If you are concerned about pooled coroutines growing a lot because a |
243 | If you are concerned about pooled coroutines growing a lot because a |
247 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
244 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
248 | { terminate }> once per second or so to slowly replenish the pool. In |
245 | { terminate }> once per second or so to slowly replenish the pool. In |
249 | addition to that, when the stacks used by a handler grows larger than 16kb |
246 | addition to that, when the stacks used by a handler grows larger than 32kb |
250 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
247 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
251 | |
248 | |
252 | =cut |
249 | =cut |
253 | |
250 | |
254 | our $POOL_SIZE = 8; |
251 | our $POOL_SIZE = 8; |
255 | our $POOL_RSS = 16 * 1024; |
252 | our $POOL_RSS = 32 * 1024; |
256 | our @async_pool; |
253 | our @async_pool; |
257 | |
254 | |
258 | sub pool_handler { |
255 | sub pool_handler { |
259 | my $cb; |
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260 | |
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261 | while () { |
256 | while () { |
262 | eval { |
257 | eval { |
263 | while () { |
258 | &{&_pool_handler} while 1; |
264 | _pool_1 $cb; |
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265 | &$cb; |
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266 | _pool_2 $cb; |
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267 | &schedule; |
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268 | } |
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269 | }; |
259 | }; |
270 | |
260 | |
271 | last if $@ eq "\3async_pool terminate\2\n"; |
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272 | warn $@ if $@; |
261 | warn $@ if $@; |
273 | } |
262 | } |
274 | } |
263 | } |
275 | |
264 | |
276 | sub async_pool(&@) { |
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277 | # this is also inlined into the unlock_scheduler |
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278 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
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279 | |
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280 | $coro->{_invoke} = [@_]; |
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281 | $coro->ready; |
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282 | |
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283 | $coro |
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284 | } |
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285 | |
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286 | =back |
265 | =back |
287 | |
266 | |
288 | =head2 STATIC METHODS |
267 | =head1 STATIC METHODS |
289 | |
268 | |
290 | Static methods are actually functions that operate on the current coroutine. |
269 | Static methods are actually functions that implicitly operate on the |
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270 | current coroutine. |
291 | |
271 | |
292 | =over 4 |
272 | =over 4 |
293 | |
273 | |
294 | =item schedule |
274 | =item schedule |
295 | |
275 | |
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… | |
307 | This makes C<schedule> I<the> generic method to use to block the current |
287 | This makes C<schedule> I<the> generic method to use to block the current |
308 | coroutine and wait for events: first you remember the current coroutine in |
288 | coroutine and wait for events: first you remember the current coroutine in |
309 | a variable, then arrange for some callback of yours to call C<< ->ready |
289 | a variable, then arrange for some callback of yours to call C<< ->ready |
310 | >> on that once some event happens, and last you call C<schedule> to put |
290 | >> on that once some event happens, and last you call C<schedule> to put |
311 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
291 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
312 | so you need to check wether the event indeed happened, e.g. by storing the |
292 | so you need to check whether the event indeed happened, e.g. by storing the |
313 | status in a variable. |
293 | status in a variable. |
314 | |
294 | |
315 | The canonical way to wait on external events is this: |
295 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
316 | |
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317 | { |
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318 | # remember current coroutine |
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319 | my $current = $Coro::current; |
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320 | |
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321 | # register a hypothetical event handler |
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322 | on_event_invoke sub { |
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323 | # wake up sleeping coroutine |
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324 | $current->ready; |
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325 | undef $current; |
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326 | }; |
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327 | |
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328 | # call schedule until event occurred. |
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329 | # in case we are woken up for other reasons |
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330 | # (current still defined), loop. |
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331 | Coro::schedule while $current; |
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332 | } |
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333 | |
296 | |
334 | =item cede |
297 | =item cede |
335 | |
298 | |
336 | "Cede" to other coroutines. This function puts the current coroutine into |
299 | "Cede" to other coroutines. This function puts the current coroutine into |
337 | the ready queue and calls C<schedule>, which has the effect of giving |
300 | the ready queue and calls C<schedule>, which has the effect of giving |
… | |
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356 | Kills/terminates/cancels all coroutines except the currently running |
319 | Kills/terminates/cancels all coroutines except the currently running |
357 | one. This is useful after a fork, either in the child or the parent, as |
320 | one. This is useful after a fork, either in the child or the parent, as |
358 | usually only one of them should inherit the running coroutines. |
321 | usually only one of them should inherit the running coroutines. |
359 | |
322 | |
360 | Note that while this will try to free some of the main programs resources, |
323 | Note that while this will try to free some of the main programs resources, |
361 | you cnanot free all of them, so if a coroutine that is not the main |
324 | you cannot free all of them, so if a coroutine that is not the main |
362 | program calls this function, there will be some one-time resource leak. |
325 | program calls this function, there will be some one-time resource leak. |
363 | |
326 | |
364 | =cut |
327 | =cut |
365 | |
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366 | sub terminate { |
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367 | $current->cancel (@_); |
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368 | } |
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369 | |
328 | |
370 | sub killall { |
329 | sub killall { |
371 | for (Coro::State::list) { |
330 | for (Coro::State::list) { |
372 | $_->cancel |
331 | $_->cancel |
373 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
332 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
374 | } |
333 | } |
375 | } |
334 | } |
376 | |
335 | |
377 | =back |
336 | =back |
378 | |
337 | |
379 | =head2 COROUTINE METHODS |
338 | =head1 COROUTINE OBJECT METHODS |
380 | |
339 | |
381 | These are the methods you can call on coroutine objects (or to create |
340 | These are the methods you can call on coroutine objects (or to create |
382 | them). |
341 | them). |
383 | |
342 | |
384 | =over 4 |
343 | =over 4 |
… | |
… | |
393 | See C<async> and C<Coro::State::new> for additional info about the |
352 | See C<async> and C<Coro::State::new> for additional info about the |
394 | coroutine environment. |
353 | coroutine environment. |
395 | |
354 | |
396 | =cut |
355 | =cut |
397 | |
356 | |
398 | sub _run_coro { |
357 | sub _coro_run { |
399 | terminate &{+shift}; |
358 | terminate &{+shift}; |
400 | } |
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|
401 | |
|
|
402 | sub new { |
|
|
403 | my $class = shift; |
|
|
404 | |
|
|
405 | $class->SUPER::new (\&_run_coro, @_) |
|
|
406 | } |
359 | } |
407 | |
360 | |
408 | =item $success = $coroutine->ready |
361 | =item $success = $coroutine->ready |
409 | |
362 | |
410 | Put the given coroutine into the end of its ready queue (there is one |
363 | Put the given coroutine into the end of its ready queue (there is one |
… | |
… | |
415 | once all the coroutines of higher priority and all coroutines of the same |
368 | once all the coroutines of higher priority and all coroutines of the same |
416 | priority that were put into the ready queue earlier have been resumed. |
369 | priority that were put into the ready queue earlier have been resumed. |
417 | |
370 | |
418 | =item $is_ready = $coroutine->is_ready |
371 | =item $is_ready = $coroutine->is_ready |
419 | |
372 | |
420 | Return wether the coroutine is currently the ready queue or not, |
373 | Return whether the coroutine is currently the ready queue or not, |
421 | |
374 | |
422 | =item $coroutine->cancel (arg...) |
375 | =item $coroutine->cancel (arg...) |
423 | |
376 | |
424 | Terminates the given coroutine and makes it return the given arguments as |
377 | Terminates the given coroutine and makes it return the given arguments as |
425 | status (default: the empty list). Never returns if the coroutine is the |
378 | status (default: the empty list). Never returns if the coroutine is the |
… | |
… | |
427 | |
380 | |
428 | =cut |
381 | =cut |
429 | |
382 | |
430 | sub cancel { |
383 | sub cancel { |
431 | my $self = shift; |
384 | my $self = shift; |
432 | $self->{_status} = [@_]; |
|
|
433 | |
385 | |
434 | if ($current == $self) { |
386 | if ($current == $self) { |
435 | push @destroy, $self; |
387 | terminate @_; |
436 | $manager->ready; |
|
|
437 | &schedule while 1; |
|
|
438 | } else { |
388 | } else { |
|
|
389 | $self->{_status} = [@_]; |
439 | $self->_cancel; |
390 | $self->_cancel; |
440 | } |
391 | } |
441 | } |
392 | } |
|
|
393 | |
|
|
394 | =item $coroutine->schedule_to |
|
|
395 | |
|
|
396 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
|
|
397 | of continuing with the next coro from the ready queue, always switch to |
|
|
398 | the given coroutine object (regardless of priority etc.). The readyness |
|
|
399 | state of that coroutine isn't changed. |
|
|
400 | |
|
|
401 | This is an advanced method for special cases - I'd love to hear about any |
|
|
402 | uses for this one. |
|
|
403 | |
|
|
404 | =item $coroutine->cede_to |
|
|
405 | |
|
|
406 | Like C<schedule_to>, but puts the current coroutine into the ready |
|
|
407 | queue. This has the effect of temporarily switching to the given |
|
|
408 | coroutine, and continuing some time later. |
|
|
409 | |
|
|
410 | This is an advanced method for special cases - I'd love to hear about any |
|
|
411 | uses for this one. |
|
|
412 | |
|
|
413 | =item $coroutine->throw ([$scalar]) |
|
|
414 | |
|
|
415 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
416 | inside the coroutine at the next convenient point in time. Otherwise |
|
|
417 | clears the exception object. |
|
|
418 | |
|
|
419 | Coro will check for the exception each time a schedule-like-function |
|
|
420 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
|
|
421 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
|
|
422 | detect this case and return early in case an exception is pending. |
|
|
423 | |
|
|
424 | The exception object will be thrown "as is" with the specified scalar in |
|
|
425 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
426 | (unlike with C<die>). |
|
|
427 | |
|
|
428 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
429 | end itself, although there is no guarantee that the exception will lead to |
|
|
430 | termination, and if the exception isn't caught it might well end the whole |
|
|
431 | program. |
|
|
432 | |
|
|
433 | You might also think of C<throw> as being the moral equivalent of |
|
|
434 | C<kill>ing a coroutine with a signal (in this case, a scalar). |
442 | |
435 | |
443 | =item $coroutine->join |
436 | =item $coroutine->join |
444 | |
437 | |
445 | Wait until the coroutine terminates and return any values given to the |
438 | Wait until the coroutine terminates and return any values given to the |
446 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
439 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
… | |
… | |
508 | higher values mean lower priority, just as in unix). |
501 | higher values mean lower priority, just as in unix). |
509 | |
502 | |
510 | =item $olddesc = $coroutine->desc ($newdesc) |
503 | =item $olddesc = $coroutine->desc ($newdesc) |
511 | |
504 | |
512 | Sets (or gets in case the argument is missing) the description for this |
505 | Sets (or gets in case the argument is missing) the description for this |
513 | coroutine. This is just a free-form string you can associate with a coroutine. |
506 | coroutine. This is just a free-form string you can associate with a |
|
|
507 | coroutine. |
514 | |
508 | |
515 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
509 | This method simply sets the C<< $coroutine->{desc} >> member to the given |
516 | can modify this member directly if you wish. |
510 | string. You can modify this member directly if you wish. |
517 | |
|
|
518 | =item $coroutine->throw ([$scalar]) |
|
|
519 | |
|
|
520 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
521 | inside the coroutine at the next convinient point in time (usually after |
|
|
522 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
523 | exception object. |
|
|
524 | |
|
|
525 | The exception object will be thrown "as is" with the specified scalar in |
|
|
526 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
527 | (unlike with C<die>). |
|
|
528 | |
|
|
529 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
530 | end itself, although there is no guarentee that the exception will lead to |
|
|
531 | termination, and if the exception isn't caught it might well end the whole |
|
|
532 | program. |
|
|
533 | |
511 | |
534 | =cut |
512 | =cut |
535 | |
513 | |
536 | sub desc { |
514 | sub desc { |
537 | my $old = $_[0]{desc}; |
515 | my $old = $_[0]{desc}; |
538 | $_[0]{desc} = $_[1] if @_ > 1; |
516 | $_[0]{desc} = $_[1] if @_ > 1; |
539 | $old; |
517 | $old; |
540 | } |
518 | } |
541 | |
519 | |
|
|
520 | sub transfer { |
|
|
521 | require Carp; |
|
|
522 | Carp::croak ("You must not call ->transfer on Coro objects. Use Coro::State objects or the ->schedule_to method. Caught"); |
|
|
523 | } |
|
|
524 | |
542 | =back |
525 | =back |
543 | |
526 | |
544 | =head2 GLOBAL FUNCTIONS |
527 | =head1 GLOBAL FUNCTIONS |
545 | |
528 | |
546 | =over 4 |
529 | =over 4 |
547 | |
530 | |
548 | =item Coro::nready |
531 | =item Coro::nready |
549 | |
532 | |
… | |
… | |
596 | original code ref will be called (with parameters) from within another |
579 | original code ref will be called (with parameters) from within another |
597 | coroutine. |
580 | coroutine. |
598 | |
581 | |
599 | The reason this function exists is that many event libraries (such as the |
582 | The reason this function exists is that many event libraries (such as the |
600 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
583 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
601 | of thread-safety). This means you must not block within event callbacks, |
584 | of reentrancy). This means you must not block within event callbacks, |
602 | otherwise you might suffer from crashes or worse. The only event library |
585 | otherwise you might suffer from crashes or worse. The only event library |
603 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
586 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
604 | |
587 | |
605 | This function allows your callbacks to block by executing them in another |
588 | This function allows your callbacks to block by executing them in another |
606 | coroutine where it is safe to block. One example where blocking is handy |
589 | coroutine where it is safe to block. One example where blocking is handy |
… | |
… | |
629 | # return immediately and can be reused) and because we cannot cede |
612 | # return immediately and can be reused) and because we cannot cede |
630 | # inside an event callback. |
613 | # inside an event callback. |
631 | our $unblock_scheduler = new Coro sub { |
614 | our $unblock_scheduler = new Coro sub { |
632 | while () { |
615 | while () { |
633 | while (my $cb = pop @unblock_queue) { |
616 | while (my $cb = pop @unblock_queue) { |
634 | # this is an inlined copy of async_pool |
617 | &async_pool (@$cb); |
635 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
636 | |
618 | |
637 | $coro->{_invoke} = $cb; |
|
|
638 | $coro->ready; |
|
|
639 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
619 | # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
620 | # as the chance is very high that the async_poll coro will be back |
|
|
621 | # in the idle state when cede returns |
|
|
622 | cede; |
640 | } |
623 | } |
641 | schedule; # sleep well |
624 | schedule; # sleep well |
642 | } |
625 | } |
643 | }; |
626 | }; |
644 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
627 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
645 | |
628 | |
646 | sub unblock_sub(&) { |
629 | sub unblock_sub(&) { |
647 | my $cb = shift; |
630 | my $cb = shift; |
648 | |
631 | |
649 | sub { |
632 | sub { |
650 | unshift @unblock_queue, [$cb, @_]; |
633 | unshift @unblock_queue, [$cb, @_]; |
651 | $unblock_scheduler->ready; |
634 | $unblock_scheduler->ready; |
652 | } |
635 | } |
653 | } |
636 | } |
654 | |
637 | |
|
|
638 | =item $cb = Coro::rouse_cb |
|
|
639 | |
|
|
640 | Create and return a "rouse callback". That's a code reference that, |
|
|
641 | when called, will remember a copy of its arguments and notify the owner |
|
|
642 | coroutine of the callback. |
|
|
643 | |
|
|
644 | See the next function. |
|
|
645 | |
|
|
646 | =item @args = Coro::rouse_wait [$cb] |
|
|
647 | |
|
|
648 | Wait for the specified rouse callback (or the last one that was created in |
|
|
649 | this coroutine). |
|
|
650 | |
|
|
651 | As soon as the callback is invoked (or when the callback was invoked |
|
|
652 | before C<rouse_wait>), it will return the arguments originally passed to |
|
|
653 | the rouse callback. |
|
|
654 | |
|
|
655 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
|
|
656 | |
655 | =back |
657 | =back |
656 | |
658 | |
657 | =cut |
659 | =cut |
658 | |
660 | |
659 | 1; |
661 | 1; |
660 | |
662 | |
|
|
663 | =head1 HOW TO WAIT FOR A CALLBACK |
|
|
664 | |
|
|
665 | It is very common for a coroutine to wait for some callback to be |
|
|
666 | called. This occurs naturally when you use coroutines in an otherwise |
|
|
667 | event-based program, or when you use event-based libraries. |
|
|
668 | |
|
|
669 | These typically register a callback for some event, and call that callback |
|
|
670 | when the event occured. In a coroutine, however, you typically want to |
|
|
671 | just wait for the event, simplyifying things. |
|
|
672 | |
|
|
673 | For example C<< AnyEvent->child >> registers a callback to be called when |
|
|
674 | a specific child has exited: |
|
|
675 | |
|
|
676 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
|
|
677 | |
|
|
678 | But from withina coroutine, you often just want to write this: |
|
|
679 | |
|
|
680 | my $status = wait_for_child $pid; |
|
|
681 | |
|
|
682 | Coro offers two functions specifically designed to make this easy, |
|
|
683 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
|
|
684 | |
|
|
685 | The first function, C<rouse_cb>, generates and returns a callback that, |
|
|
686 | when invoked, will save its arguments and notify the coroutine that |
|
|
687 | created the callback. |
|
|
688 | |
|
|
689 | The second function, C<rouse_wait>, waits for the callback to be called |
|
|
690 | (by calling C<schedule> to go to sleep) and returns the arguments |
|
|
691 | originally passed to the callback. |
|
|
692 | |
|
|
693 | Using these functions, it becomes easy to write the C<wait_for_child> |
|
|
694 | function mentioned above: |
|
|
695 | |
|
|
696 | sub wait_for_child($) { |
|
|
697 | my ($pid) = @_; |
|
|
698 | |
|
|
699 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
|
|
700 | |
|
|
701 | my ($rpid, $rstatus) = Coro::rouse_wait; |
|
|
702 | $rstatus |
|
|
703 | } |
|
|
704 | |
|
|
705 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
|
|
706 | you can roll your own, using C<schedule>: |
|
|
707 | |
|
|
708 | sub wait_for_child($) { |
|
|
709 | my ($pid) = @_; |
|
|
710 | |
|
|
711 | # store the current coroutine in $current, |
|
|
712 | # and provide result variables for the closure passed to ->child |
|
|
713 | my $current = $Coro::current; |
|
|
714 | my ($done, $rstatus); |
|
|
715 | |
|
|
716 | # pass a closure to ->child |
|
|
717 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
|
|
718 | $rstatus = $_[1]; # remember rstatus |
|
|
719 | $done = 1; # mark $rstatus as valud |
|
|
720 | }); |
|
|
721 | |
|
|
722 | # wait until the closure has been called |
|
|
723 | schedule while !$done; |
|
|
724 | |
|
|
725 | $rstatus |
|
|
726 | } |
|
|
727 | |
|
|
728 | |
661 | =head1 BUGS/LIMITATIONS |
729 | =head1 BUGS/LIMITATIONS |
662 | |
730 | |
|
|
731 | =over 4 |
|
|
732 | |
|
|
733 | =item fork with pthread backend |
|
|
734 | |
|
|
735 | When Coro is compiled using the pthread backend (which isn't recommended |
|
|
736 | but required on many BSDs as their libcs are completely broken), then |
|
|
737 | coroutines will not survive a fork. There is no known workaround except to |
|
|
738 | fix your libc and use a saner backend. |
|
|
739 | |
|
|
740 | =item perl process emulation ("threads") |
|
|
741 | |
663 | This module is not perl-pseudo-thread-safe. You should only ever use this |
742 | This module is not perl-pseudo-thread-safe. You should only ever use this |
664 | module from the same thread (this requirement might be removed in the |
743 | module from the first thread (this requirement might be removed in the |
665 | future to allow per-thread schedulers, but Coro::State does not yet allow |
744 | future to allow per-thread schedulers, but Coro::State does not yet allow |
666 | this). I recommend disabling thread support and using processes, as this |
745 | this). I recommend disabling thread support and using processes, as having |
667 | is much faster and uses less memory. |
746 | the windows process emulation enabled under unix roughly halves perl |
|
|
747 | performance, even when not used. |
|
|
748 | |
|
|
749 | =item coroutine switching not signal safe |
|
|
750 | |
|
|
751 | You must not switch to another coroutine from within a signal handler |
|
|
752 | (only relevant with %SIG - most event libraries provide safe signals). |
|
|
753 | |
|
|
754 | That means you I<MUST NOT> call any function that might "block" the |
|
|
755 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
|
|
756 | anything that calls those. Everything else, including calling C<ready>, |
|
|
757 | works. |
|
|
758 | |
|
|
759 | =back |
|
|
760 | |
668 | |
761 | |
669 | =head1 SEE ALSO |
762 | =head1 SEE ALSO |
670 | |
763 | |
671 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
764 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
672 | |
765 | |
673 | Debugging: L<Coro::Debug>. |
766 | Debugging: L<Coro::Debug>. |
674 | |
767 | |
675 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
768 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
676 | |
769 | |
677 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
770 | Locking and IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, |
|
|
771 | L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
678 | |
772 | |
679 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
773 | I/O and Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
680 | |
774 | |
681 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
775 | Compatibility with other modules: L<Coro::LWP> (but see also L<AnyEvent::HTTP> for |
|
|
776 | a better-working alternative), L<Coro::BDB>, L<Coro::Storable>, |
|
|
777 | L<Coro::Select>. |
682 | |
778 | |
683 | XS API: L<Coro::MakeMaker>. |
779 | XS API: L<Coro::MakeMaker>. |
684 | |
780 | |
685 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
781 | Low level Configuration, Thread Environment, Continuations: L<Coro::State>. |
686 | |
782 | |
687 | =head1 AUTHOR |
783 | =head1 AUTHOR |
688 | |
784 | |
689 | Marc Lehmann <schmorp@schmorp.de> |
785 | Marc Lehmann <schmorp@schmorp.de> |
690 | http://home.schmorp.de/ |
786 | http://home.schmorp.de/ |