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11 print "2\n"; 11 print "2\n";
12 cede; # yield back to main 12 cede; # yield back to main
13 print "4\n"; 13 print "4\n";
14 }; 14 };
15 print "1\n"; 15 print "1\n";
16 cede; # yield to coroutine 16 cede; # yield to coro
17 print "3\n"; 17 print "3\n";
18 cede; # and again 18 cede; # and again
19 19
20 # use locking 20 # use locking
21 use Coro::Semaphore; 21 use Coro::Semaphore;
29=head1 DESCRIPTION 29=head1 DESCRIPTION
30 30
31For a tutorial-style introduction, please read the L<Coro::Intro> 31For a tutorial-style introduction, please read the L<Coro::Intro>
32manpage. This manpage mainly contains reference information. 32manpage. This manpage mainly contains reference information.
33 33
34This module collection manages continuations in general, most often 34This module collection manages continuations in general, most often in
35in the form of cooperative threads (also called coroutines in the 35the form of cooperative threads (also called coros, or simply "coro"
36documentation). They are similar to kernel threads but don't (in general) 36in the documentation). They are similar to kernel threads but don't (in
37run in parallel at the same time even on SMP machines. The specific flavor 37general) run in parallel at the same time even on SMP machines. The
38of thread offered by this module also guarantees you that it will not 38specific flavor of thread offered by this module also guarantees you that
39switch between threads unless necessary, at easily-identified points in 39it will not switch between threads unless necessary, at easily-identified
40your program, so locking and parallel access are rarely an issue, making 40points in your program, so locking and parallel access are rarely an
41thread programming much safer and easier than using other thread models. 41issue, making thread programming much safer and easier than using other
42thread models.
42 43
43Unlike the so-called "Perl threads" (which are not actually real threads 44Unlike the so-called "Perl threads" (which are not actually real threads
44but only the windows process emulation ported to unix), Coro provides a 45but only the windows process emulation ported to unix), Coro provides a
45full shared address space, which makes communication between threads 46full shared address space, which makes communication between threads
46very easy. And threads are fast, too: disabling the Windows process 47very easy. And threads are fast, too: disabling the Windows process
73use Coro::State; 74use Coro::State;
74 75
75use base qw(Coro::State Exporter); 76use base qw(Coro::State Exporter);
76 77
77our $idle; # idle handler 78our $idle; # idle handler
78our $main; # main coroutine 79our $main; # main coro
79our $current; # current coroutine 80our $current; # current coro
80 81
81our $VERSION = 5.13; 82our $VERSION = 5.13;
82 83
83our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); 84our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
84our %EXPORT_TAGS = ( 85our %EXPORT_TAGS = (
90 91
91=over 4 92=over 4
92 93
93=item $Coro::main 94=item $Coro::main
94 95
95This variable stores the coroutine object that represents the main 96This variable stores the Coro object that represents the main
96program. While you cna C<ready> it and do most other things you can do to 97program. While you cna C<ready> it and do most other things you can do to
97coroutines, it is mainly useful to compare again C<$Coro::current>, to see 98coro, it is mainly useful to compare again C<$Coro::current>, to see
98whether you are running in the main program or not. 99whether you are running in the main program or not.
99 100
100=cut 101=cut
101 102
102# $main is now being initialised by Coro::State 103# $main is now being initialised by Coro::State
103 104
104=item $Coro::current 105=item $Coro::current
105 106
106The coroutine object representing the current coroutine (the last 107The Coro object representing the current coro (the last
107coroutine that the Coro scheduler switched to). The initial value is 108coro that the Coro scheduler switched to). The initial value is
108C<$Coro::main> (of course). 109C<$Coro::main> (of course).
109 110
110This variable is B<strictly> I<read-only>. You can take copies of the 111This variable is B<strictly> I<read-only>. You can take copies of the
111value stored in it and use it as any other coroutine object, but you must 112value stored in it and use it as any other Coro object, but you must
112not otherwise modify the variable itself. 113not otherwise modify the variable itself.
113 114
114=cut 115=cut
115 116
116sub current() { $current } # [DEPRECATED] 117sub current() { $current } # [DEPRECATED]
119 120
120This variable is mainly useful to integrate Coro into event loops. It is 121This variable is mainly useful to integrate Coro into event loops. It is
121usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is 122usually better to rely on L<Coro::AnyEvent> or L<Coro::EV>, as this is
122pretty low-level functionality. 123pretty low-level functionality.
123 124
124This variable stores either a coroutine or a callback. 125This variable stores either a Coro object or a callback.
125 126
126If it is a callback, the it is called whenever the scheduler finds no 127If it is a callback, the it is called whenever the scheduler finds no
127ready coroutines to run. The default implementation prints "FATAL: 128ready coros to run. The default implementation prints "FATAL:
128deadlock detected" and exits, because the program has no other way to 129deadlock detected" and exits, because the program has no other way to
129continue. 130continue.
130 131
131If it is a coroutine object, then this object will be readied (without 132If it is a coro object, then this object will be readied (without
132invoking any ready hooks, however) when the scheduler finds no other ready 133invoking any ready hooks, however) when the scheduler finds no other ready
133coroutines to run. 134coros to run.
134 135
135This hook is overwritten by modules such as C<Coro::EV> and 136This hook is overwritten by modules such as C<Coro::EV> and
136C<Coro::AnyEvent> to wait on an external event that hopefully wake up a 137C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
137coroutine so the scheduler can run it. 138coro so the scheduler can run it.
138 139
139Note that the callback I<must not>, under any circumstances, block 140Note that the callback I<must not>, under any circumstances, block
140the current coroutine. Normally, this is achieved by having an "idle 141the current coro. Normally, this is achieved by having an "idle
141coroutine" that calls the event loop and then blocks again, and then 142coro" that calls the event loop and then blocks again, and then
142readying that coroutine in the idle handler, or by simply placing the idle 143readying that coro in the idle handler, or by simply placing the idle
143coroutine in this variable. 144coro in this variable.
144 145
145See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this 146See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
146technique. 147technique.
147 148
148Please note that if your callback recursively invokes perl (e.g. for event 149Please note that if your callback recursively invokes perl (e.g. for event
153$idle = sub { 154$idle = sub {
154 require Carp; 155 require Carp;
155 Carp::croak ("FATAL: deadlock detected"); 156 Carp::croak ("FATAL: deadlock detected");
156}; 157};
157 158
158# this coroutine is necessary because a coroutine 159# this coro is necessary because a coro
159# cannot destroy itself. 160# cannot destroy itself.
160our @destroy; 161our @destroy;
161our $manager; 162our $manager;
162 163
163$manager = new Coro sub { 164$manager = new Coro sub {
164 while () { 165 while () {
165 Coro::_cancel shift @destroy 166 Coro::State::cancel shift @destroy
166 while @destroy; 167 while @destroy;
167 168
168 &schedule; 169 &schedule;
169 } 170 }
170}; 171};
171$manager->{desc} = "[coro manager]"; 172$manager->{desc} = "[coro manager]";
172$manager->prio (PRIO_MAX); 173$manager->prio (PRIO_MAX);
173 174
174=back 175=back
175 176
176=head1 SIMPLE COROUTINE CREATION 177=head1 SIMPLE CORO CREATION
177 178
178=over 4 179=over 4
179 180
180=item async { ... } [@args...] 181=item async { ... } [@args...]
181 182
182Create a new coroutine and return its coroutine object (usually 183Create a new coro and return its Coro object (usually
183unused). The coroutine will be put into the ready queue, so 184unused). The coro will be put into the ready queue, so
184it will start running automatically on the next scheduler run. 185it will start running automatically on the next scheduler run.
185 186
186The first argument is a codeblock/closure that should be executed in the 187The first argument is a codeblock/closure that should be executed in the
187coroutine. When it returns argument returns the coroutine is automatically 188coro. When it returns argument returns the coro is automatically
188terminated. 189terminated.
189 190
190The remaining arguments are passed as arguments to the closure. 191The remaining arguments are passed as arguments to the closure.
191 192
192See the C<Coro::State::new> constructor for info about the coroutine 193See the C<Coro::State::new> constructor for info about the coro
193environment in which coroutines are executed. 194environment in which coro are executed.
194 195
195Calling C<exit> in a coroutine will do the same as calling exit outside 196Calling C<exit> in a coro will do the same as calling exit outside
196the coroutine. Likewise, when the coroutine dies, the program will exit, 197the coro. Likewise, when the coro dies, the program will exit,
197just as it would in the main program. 198just as it would in the main program.
198 199
199If you do not want that, you can provide a default C<die> handler, or 200If you do not want that, you can provide a default C<die> handler, or
200simply avoid dieing (by use of C<eval>). 201simply avoid dieing (by use of C<eval>).
201 202
202Example: Create a new coroutine that just prints its arguments. 203Example: Create a new coro that just prints its arguments.
203 204
204 async { 205 async {
205 print "@_\n"; 206 print "@_\n";
206 } 1,2,3,4; 207 } 1,2,3,4;
207 208
213 $coro 214 $coro
214} 215}
215 216
216=item async_pool { ... } [@args...] 217=item async_pool { ... } [@args...]
217 218
218Similar to C<async>, but uses a coroutine pool, so you should not call 219Similar to C<async>, but uses a coro pool, so you should not call
219terminate or join on it (although you are allowed to), and you get a 220terminate or join on it (although you are allowed to), and you get a
220coroutine that might have executed other code already (which can be good 221coro that might have executed other code already (which can be good
221or bad :). 222or bad :).
222 223
223On the plus side, this function is about twice as fast as creating (and 224On the plus side, this function is about twice as fast as creating (and
224destroying) a completely new coroutine, so if you need a lot of generic 225destroying) a completely new coro, so if you need a lot of generic
225coroutines in quick successsion, use C<async_pool>, not C<async>. 226coros in quick successsion, use C<async_pool>, not C<async>.
226 227
227The code block is executed in an C<eval> context and a warning will be 228The code block is executed in an C<eval> context and a warning will be
228issued in case of an exception instead of terminating the program, as 229issued in case of an exception instead of terminating the program, as
229C<async> does. As the coroutine is being reused, stuff like C<on_destroy> 230C<async> does. As the coro is being reused, stuff like C<on_destroy>
230will not work in the expected way, unless you call terminate or cancel, 231will not work in the expected way, unless you call terminate or cancel,
231which somehow defeats the purpose of pooling (but is fine in the 232which somehow defeats the purpose of pooling (but is fine in the
232exceptional case). 233exceptional case).
233 234
234The priority will be reset to C<0> after each run, tracing will be 235The priority will be reset to C<0> after each run, tracing will be
235disabled, the description will be reset and the default output filehandle 236disabled, the description will be reset and the default output filehandle
236gets restored, so you can change all these. Otherwise the coroutine will 237gets restored, so you can change all these. Otherwise the coro will
237be re-used "as-is": most notably if you change other per-coroutine global 238be re-used "as-is": most notably if you change other per-coro global
238stuff such as C<$/> you I<must needs> revert that change, which is most 239stuff such as C<$/> you I<must needs> revert that change, which is most
239simply done by using local as in: C<< local $/ >>. 240simply done by using local as in: C<< local $/ >>.
240 241
241The idle pool size is limited to C<8> idle coroutines (this can be 242The idle pool size is limited to C<8> idle coros (this can be
242adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle 243adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle
243coros as required. 244coros as required.
244 245
245If you are concerned about pooled coroutines growing a lot because a 246If you are concerned about pooled coros growing a lot because a
246single C<async_pool> used a lot of stackspace you can e.g. C<async_pool 247single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
247{ terminate }> once per second or so to slowly replenish the pool. In 248{ terminate }> once per second or so to slowly replenish the pool. In
248addition to that, when the stacks used by a handler grows larger than 32kb 249addition to that, when the stacks used by a handler grows larger than 32kb
249(adjustable via $Coro::POOL_RSS) it will also be destroyed. 250(adjustable via $Coro::POOL_RSS) it will also be destroyed.
250 251
267=back 268=back
268 269
269=head1 STATIC METHODS 270=head1 STATIC METHODS
270 271
271Static methods are actually functions that implicitly operate on the 272Static methods are actually functions that implicitly operate on the
272current coroutine. 273current coro.
273 274
274=over 4 275=over 4
275 276
276=item schedule 277=item schedule
277 278
278Calls the scheduler. The scheduler will find the next coroutine that is 279Calls the scheduler. The scheduler will find the next coro that is
279to be run from the ready queue and switches to it. The next coroutine 280to be run from the ready queue and switches to it. The next coro
280to be run is simply the one with the highest priority that is longest 281to be run is simply the one with the highest priority that is longest
281in its ready queue. If there is no coroutine ready, it will clal the 282in its ready queue. If there is no coro ready, it will clal the
282C<$Coro::idle> hook. 283C<$Coro::idle> hook.
283 284
284Please note that the current coroutine will I<not> be put into the ready 285Please note that the current coro will I<not> be put into the ready
285queue, so calling this function usually means you will never be called 286queue, so calling this function usually means you will never be called
286again unless something else (e.g. an event handler) calls C<< ->ready >>, 287again unless something else (e.g. an event handler) calls C<< ->ready >>,
287thus waking you up. 288thus waking you up.
288 289
289This makes C<schedule> I<the> generic method to use to block the current 290This makes C<schedule> I<the> generic method to use to block the current
290coroutine and wait for events: first you remember the current coroutine in 291coro and wait for events: first you remember the current coro in
291a variable, then arrange for some callback of yours to call C<< ->ready 292a variable, then arrange for some callback of yours to call C<< ->ready
292>> on that once some event happens, and last you call C<schedule> to put 293>> on that once some event happens, and last you call C<schedule> to put
293yourself to sleep. Note that a lot of things can wake your coroutine up, 294yourself to sleep. Note that a lot of things can wake your coro up,
294so you need to check whether the event indeed happened, e.g. by storing the 295so you need to check whether the event indeed happened, e.g. by storing the
295status in a variable. 296status in a variable.
296 297
297See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. 298See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks.
298 299
299=item cede 300=item cede
300 301
301"Cede" to other coroutines. This function puts the current coroutine into 302"Cede" to other coros. This function puts the current coro into
302the ready queue and calls C<schedule>, which has the effect of giving 303the ready queue and calls C<schedule>, which has the effect of giving
303up the current "timeslice" to other coroutines of the same or higher 304up the current "timeslice" to other coros of the same or higher
304priority. Once your coroutine gets its turn again it will automatically be 305priority. Once your coro gets its turn again it will automatically be
305resumed. 306resumed.
306 307
307This function is often called C<yield> in other languages. 308This function is often called C<yield> in other languages.
308 309
309=item Coro::cede_notself 310=item Coro::cede_notself
310 311
311Works like cede, but is not exported by default and will cede to I<any> 312Works like cede, but is not exported by default and will cede to I<any>
312coroutine, regardless of priority. This is useful sometimes to ensure 313coro, regardless of priority. This is useful sometimes to ensure
313progress is made. 314progress is made.
314 315
315=item terminate [arg...] 316=item terminate [arg...]
316 317
317Terminates the current coroutine with the given status values (see L<cancel>). 318Terminates the current coro with the given status values (see L<cancel>).
318 319
319=item Coro::on_enter BLOCK, Coro::on_leave BLOCK 320=item Coro::on_enter BLOCK, Coro::on_leave BLOCK
320 321
321These function install enter and leave winders in the current scope. The 322These function install enter and leave winders in the current scope. The
322enter block will be executed when on_enter is called and whenever the 323enter block will be executed when on_enter is called and whenever the
323current coroutine is re-entered by the scheduler, while the leave block is 324current coro is re-entered by the scheduler, while the leave block is
324executed whenever the current coroutine is blocked by the scheduler, and 325executed whenever the current coro is blocked by the scheduler, and
325also when the containing scope is exited (by whatever means, be it exit, 326also when the containing scope is exited (by whatever means, be it exit,
326die, last etc.). 327die, last etc.).
327 328
328I<Neither invoking the scheduler, nor exceptions, are allowed within those 329I<Neither invoking the scheduler, nor exceptions, are allowed within those
329BLOCKs>. That means: do not even think about calling C<die> without an 330BLOCKs>. That means: do not even think about calling C<die> without an
332Since both BLOCKs are tied to the current scope, they will automatically 333Since both BLOCKs are tied to the current scope, they will automatically
333be removed when the current scope exits. 334be removed when the current scope exits.
334 335
335These functions implement the same concept as C<dynamic-wind> in scheme 336These functions implement the same concept as C<dynamic-wind> in scheme
336does, and are useful when you want to localise some resource to a specific 337does, and are useful when you want to localise some resource to a specific
337coroutine. 338coro.
338 339
339They slow down coroutine switching considerably for coroutines that use 340They slow down coro switching considerably for coros that use
340them (But coroutine switching is still reasonably fast if the handlers are 341them (But coro switching is still reasonably fast if the handlers are
341fast). 342fast).
342 343
343These functions are best understood by an example: The following function 344These functions are best understood by an example: The following function
344will change the current timezone to "Antarctica/South_Pole", which 345will change the current timezone to "Antarctica/South_Pole", which
345requires a call to C<tzset>, but by using C<on_enter> and C<on_leave>, 346requires a call to C<tzset>, but by using C<on_enter> and C<on_leave>,
346which remember/change the current timezone and restore the previous 347which remember/change the current timezone and restore the previous
347value, respectively, the timezone is only changes for the coroutine that 348value, respectively, the timezone is only changes for the coro that
348installed those handlers. 349installed those handlers.
349 350
350 use POSIX qw(tzset); 351 use POSIX qw(tzset);
351 352
352 async { 353 async {
363 $ENV{TZ} = $old_tz; 364 $ENV{TZ} = $old_tz;
364 tzset; # restore old value 365 tzset; # restore old value
365 }; 366 };
366 367
367 # at this place, the timezone is Antarctica/South_Pole, 368 # at this place, the timezone is Antarctica/South_Pole,
368 # without disturbing the TZ of any other coroutine. 369 # without disturbing the TZ of any other coro.
369 }; 370 };
370 371
371This can be used to localise about any resource (locale, uid, current 372This can be used to localise about any resource (locale, uid, current
372working directory etc.) to a block, despite the existance of other 373working directory etc.) to a block, despite the existance of other
373coroutines. 374coros.
374 375
375=item killall 376=item killall
376 377
377Kills/terminates/cancels all coroutines except the currently running one. 378Kills/terminates/cancels all coros except the currently running one.
378 379
379Note that while this will try to free some of the main interpreter 380Note that while this will try to free some of the main interpreter
380resources if the calling coroutine isn't the main coroutine, but one 381resources if the calling coro isn't the main coro, but one
381cannot free all of them, so if a coroutine that is not the main coroutine 382cannot free all of them, so if a coro that is not the main coro
382calls this function, there will be some one-time resource leak. 383calls this function, there will be some one-time resource leak.
383 384
384=cut 385=cut
385 386
386sub killall { 387sub killall {
390 } 391 }
391} 392}
392 393
393=back 394=back
394 395
395=head1 COROUTINE OBJECT METHODS 396=head1 CORO OBJECT METHODS
396 397
397These are the methods you can call on coroutine objects (or to create 398These are the methods you can call on coro objects (or to create
398them). 399them).
399 400
400=over 4 401=over 4
401 402
402=item new Coro \&sub [, @args...] 403=item new Coro \&sub [, @args...]
403 404
404Create a new coroutine and return it. When the sub returns, the coroutine 405Create a new coro and return it. When the sub returns, the coro
405automatically terminates as if C<terminate> with the returned values were 406automatically terminates as if C<terminate> with the returned values were
406called. To make the coroutine run you must first put it into the ready 407called. To make the coro run you must first put it into the ready
407queue by calling the ready method. 408queue by calling the ready method.
408 409
409See C<async> and C<Coro::State::new> for additional info about the 410See C<async> and C<Coro::State::new> for additional info about the
410coroutine environment. 411coro environment.
411 412
412=cut 413=cut
413 414
414sub _coro_run { 415sub _coro_run {
415 terminate &{+shift}; 416 terminate &{+shift};
416} 417}
417 418
418=item $success = $coroutine->ready 419=item $success = $coro->ready
419 420
420Put the given coroutine into the end of its ready queue (there is one 421Put the given coro into the end of its ready queue (there is one
421queue for each priority) and return true. If the coroutine is already in 422queue for each priority) and return true. If the coro is already in
422the ready queue, do nothing and return false. 423the ready queue, do nothing and return false.
423 424
424This ensures that the scheduler will resume this coroutine automatically 425This ensures that the scheduler will resume this coro automatically
425once all the coroutines of higher priority and all coroutines of the same 426once all the coro of higher priority and all coro of the same
426priority that were put into the ready queue earlier have been resumed. 427priority that were put into the ready queue earlier have been resumed.
427 428
428=item $is_ready = $coroutine->is_ready 429=item $is_ready = $coro->is_ready
429 430
430Return whether the coroutine is currently the ready queue or not, 431Returns true iff the Coro object is in the ready queue. Unless the Coro
432object gets destroyed, it will eventually be scheduled by the scheduler.
431 433
434=item $is_running = $coro->is_running
435
436Returns true iff the Coro object is currently running. Only one Coro object
437can ever be in the running state (but it currently is possible to have
438multiple running Coro::States).
439
440=item $is_suspended = $coro->is_suspended
441
442Returns true iff this Coro object has been suspended. Suspended Coros will
443not ever be scheduled.
444
432=item $coroutine->cancel (arg...) 445=item $coro->cancel (arg...)
433 446
434Terminates the given coroutine and makes it return the given arguments as 447Terminates the given Coro and makes it return the given arguments as
435status (default: the empty list). Never returns if the coroutine is the 448status (default: the empty list). Never returns if the Coro is the
436current coroutine. 449current Coro.
437 450
438=cut 451=cut
439 452
440sub cancel { 453sub cancel {
441 my $self = shift; 454 my $self = shift;
442 455
443 if ($current == $self) { 456 if ($current == $self) {
444 terminate @_; 457 terminate @_;
445 } else { 458 } else {
446 $self->{_status} = [@_]; 459 $self->{_status} = [@_];
447 $self->_cancel; 460 Coro::State::cancel $self;
448 } 461 }
449} 462}
450 463
451=item $coroutine->schedule_to 464=item $coro->schedule_to
452 465
453Puts the current coroutine to sleep (like C<Coro::schedule>), but instead 466Puts the current coro to sleep (like C<Coro::schedule>), but instead
454of continuing with the next coro from the ready queue, always switch to 467of continuing with the next coro from the ready queue, always switch to
455the given coroutine object (regardless of priority etc.). The readyness 468the given coro object (regardless of priority etc.). The readyness
456state of that coroutine isn't changed. 469state of that coro isn't changed.
457 470
458This is an advanced method for special cases - I'd love to hear about any 471This is an advanced method for special cases - I'd love to hear about any
459uses for this one. 472uses for this one.
460 473
461=item $coroutine->cede_to 474=item $coro->cede_to
462 475
463Like C<schedule_to>, but puts the current coroutine into the ready 476Like C<schedule_to>, but puts the current coro into the ready
464queue. This has the effect of temporarily switching to the given 477queue. This has the effect of temporarily switching to the given
465coroutine, and continuing some time later. 478coro, and continuing some time later.
466 479
467This is an advanced method for special cases - I'd love to hear about any 480This is an advanced method for special cases - I'd love to hear about any
468uses for this one. 481uses for this one.
469 482
470=item $coroutine->throw ([$scalar]) 483=item $coro->throw ([$scalar])
471 484
472If C<$throw> is specified and defined, it will be thrown as an exception 485If C<$throw> is specified and defined, it will be thrown as an exception
473inside the coroutine at the next convenient point in time. Otherwise 486inside the coro at the next convenient point in time. Otherwise
474clears the exception object. 487clears the exception object.
475 488
476Coro will check for the exception each time a schedule-like-function 489Coro will check for the exception each time a schedule-like-function
477returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down 490returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down
478>>, C<< Coro::Handle->readable >> and so on. Most of these functions 491>>, C<< Coro::Handle->readable >> and so on. Most of these functions
480 493
481The exception object will be thrown "as is" with the specified scalar in 494The exception object will be thrown "as is" with the specified scalar in
482C<$@>, i.e. if it is a string, no line number or newline will be appended 495C<$@>, i.e. if it is a string, no line number or newline will be appended
483(unlike with C<die>). 496(unlike with C<die>).
484 497
485This can be used as a softer means than C<cancel> to ask a coroutine to 498This can be used as a softer means than C<cancel> to ask a coro to
486end itself, although there is no guarantee that the exception will lead to 499end itself, although there is no guarantee that the exception will lead to
487termination, and if the exception isn't caught it might well end the whole 500termination, and if the exception isn't caught it might well end the whole
488program. 501program.
489 502
490You might also think of C<throw> as being the moral equivalent of 503You might also think of C<throw> as being the moral equivalent of
491C<kill>ing a coroutine with a signal (in this case, a scalar). 504C<kill>ing a coro with a signal (in this case, a scalar).
492 505
493=item $coroutine->join 506=item $coro->join
494 507
495Wait until the coroutine terminates and return any values given to the 508Wait until the coro terminates and return any values given to the
496C<terminate> or C<cancel> functions. C<join> can be called concurrently 509C<terminate> or C<cancel> functions. C<join> can be called concurrently
497from multiple coroutines, and all will be resumed and given the status 510from multiple coro, and all will be resumed and given the status
498return once the C<$coroutine> terminates. 511return once the C<$coro> terminates.
499 512
500=cut 513=cut
501 514
502sub join { 515sub join {
503 my $self = shift; 516 my $self = shift;
514 } 527 }
515 528
516 wantarray ? @{$self->{_status}} : $self->{_status}[0]; 529 wantarray ? @{$self->{_status}} : $self->{_status}[0];
517} 530}
518 531
519=item $coroutine->on_destroy (\&cb) 532=item $coro->on_destroy (\&cb)
520 533
521Registers a callback that is called when this coroutine gets destroyed, 534Registers a callback that is called when this coro gets destroyed,
522but before it is joined. The callback gets passed the terminate arguments, 535but before it is joined. The callback gets passed the terminate arguments,
523if any, and I<must not> die, under any circumstances. 536if any, and I<must not> die, under any circumstances.
524 537
525=cut 538=cut
526 539
528 my ($self, $cb) = @_; 541 my ($self, $cb) = @_;
529 542
530 push @{ $self->{_on_destroy} }, $cb; 543 push @{ $self->{_on_destroy} }, $cb;
531} 544}
532 545
533=item $oldprio = $coroutine->prio ($newprio) 546=item $oldprio = $coro->prio ($newprio)
534 547
535Sets (or gets, if the argument is missing) the priority of the 548Sets (or gets, if the argument is missing) the priority of the
536coroutine. Higher priority coroutines get run before lower priority 549coro. Higher priority coro get run before lower priority
537coroutines. Priorities are small signed integers (currently -4 .. +3), 550coro. Priorities are small signed integers (currently -4 .. +3),
538that you can refer to using PRIO_xxx constants (use the import tag :prio 551that you can refer to using PRIO_xxx constants (use the import tag :prio
539to get then): 552to get then):
540 553
541 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN 554 PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
542 3 > 1 > 0 > -1 > -3 > -4 555 3 > 1 > 0 > -1 > -3 > -4
543 556
544 # set priority to HIGH 557 # set priority to HIGH
545 current->prio(PRIO_HIGH); 558 current->prio (PRIO_HIGH);
546 559
547The idle coroutine ($Coro::idle) always has a lower priority than any 560The idle coro ($Coro::idle) always has a lower priority than any
548existing coroutine. 561existing coro.
549 562
550Changing the priority of the current coroutine will take effect immediately, 563Changing the priority of the current coro will take effect immediately,
551but changing the priority of coroutines in the ready queue (but not 564but changing the priority of coro in the ready queue (but not
552running) will only take effect after the next schedule (of that 565running) will only take effect after the next schedule (of that
553coroutine). This is a bug that will be fixed in some future version. 566coro). This is a bug that will be fixed in some future version.
554 567
555=item $newprio = $coroutine->nice ($change) 568=item $newprio = $coro->nice ($change)
556 569
557Similar to C<prio>, but subtract the given value from the priority (i.e. 570Similar to C<prio>, but subtract the given value from the priority (i.e.
558higher values mean lower priority, just as in unix). 571higher values mean lower priority, just as in unix).
559 572
560=item $olddesc = $coroutine->desc ($newdesc) 573=item $olddesc = $coro->desc ($newdesc)
561 574
562Sets (or gets in case the argument is missing) the description for this 575Sets (or gets in case the argument is missing) the description for this
563coroutine. This is just a free-form string you can associate with a 576coro. This is just a free-form string you can associate with a
564coroutine. 577coro.
565 578
566This method simply sets the C<< $coroutine->{desc} >> member to the given 579This method simply sets the C<< $coro->{desc} >> member to the given
567string. You can modify this member directly if you wish. 580string. You can modify this member directly if you wish.
568 581
569=cut 582=cut
570 583
571sub desc { 584sub desc {
585 598
586=over 4 599=over 4
587 600
588=item Coro::nready 601=item Coro::nready
589 602
590Returns the number of coroutines that are currently in the ready state, 603Returns the number of coro that are currently in the ready state,
591i.e. that can be switched to by calling C<schedule> directory or 604i.e. that can be switched to by calling C<schedule> directory or
592indirectly. The value C<0> means that the only runnable coroutine is the 605indirectly. The value C<0> means that the only runnable coro is the
593currently running one, so C<cede> would have no effect, and C<schedule> 606currently running one, so C<cede> would have no effect, and C<schedule>
594would cause a deadlock unless there is an idle handler that wakes up some 607would cause a deadlock unless there is an idle handler that wakes up some
595coroutines. 608coro.
596 609
597=item my $guard = Coro::guard { ... } 610=item my $guard = Coro::guard { ... }
598 611
599This function still exists, but is deprecated. Please use the 612This function still exists, but is deprecated. Please use the
600C<Guard::guard> function instead. 613C<Guard::guard> function instead.
607 620
608This utility function takes a BLOCK or code reference and "unblocks" it, 621This utility function takes a BLOCK or code reference and "unblocks" it,
609returning a new coderef. Unblocking means that calling the new coderef 622returning a new coderef. Unblocking means that calling the new coderef
610will return immediately without blocking, returning nothing, while the 623will return immediately without blocking, returning nothing, while the
611original code ref will be called (with parameters) from within another 624original code ref will be called (with parameters) from within another
612coroutine. 625coro.
613 626
614The reason this function exists is that many event libraries (such as the 627The reason this function exists is that many event libraries (such as the
615venerable L<Event|Event> module) are not coroutine-safe (a weaker form 628venerable L<Event|Event> module) are not thread-safe (a weaker form
616of reentrancy). This means you must not block within event callbacks, 629of reentrancy). This means you must not block within event callbacks,
617otherwise you might suffer from crashes or worse. The only event library 630otherwise you might suffer from crashes or worse. The only event library
618currently known that is safe to use without C<unblock_sub> is L<EV>. 631currently known that is safe to use without C<unblock_sub> is L<EV>.
619 632
620This function allows your callbacks to block by executing them in another 633This function allows your callbacks to block by executing them in another
621coroutine where it is safe to block. One example where blocking is handy 634coro where it is safe to block. One example where blocking is handy
622is when you use the L<Coro::AIO|Coro::AIO> functions to save results to 635is when you use the L<Coro::AIO|Coro::AIO> functions to save results to
623disk, for example. 636disk, for example.
624 637
625In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when 638In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
626creating event callbacks that want to block. 639creating event callbacks that want to block.
627 640
628If your handler does not plan to block (e.g. simply sends a message to 641If your handler does not plan to block (e.g. simply sends a message to
629another coroutine, or puts some other coroutine into the ready queue), 642another coro, or puts some other coro into the ready queue), there is
630there is no reason to use C<unblock_sub>. 643no reason to use C<unblock_sub>.
631 644
632Note that you also need to use C<unblock_sub> for any other callbacks that 645Note that you also need to use C<unblock_sub> for any other callbacks that
633are indirectly executed by any C-based event loop. For example, when you 646are indirectly executed by any C-based event loop. For example, when you
634use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it 647use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
635provides callbacks that are the result of some event callback, then you 648provides callbacks that are the result of some event callback, then you
669 682
670=item $cb = Coro::rouse_cb 683=item $cb = Coro::rouse_cb
671 684
672Create and return a "rouse callback". That's a code reference that, 685Create and return a "rouse callback". That's a code reference that,
673when called, will remember a copy of its arguments and notify the owner 686when called, will remember a copy of its arguments and notify the owner
674coroutine of the callback. 687coro of the callback.
675 688
676See the next function. 689See the next function.
677 690
678=item @args = Coro::rouse_wait [$cb] 691=item @args = Coro::rouse_wait [$cb]
679 692
680Wait for the specified rouse callback (or the last one that was created in 693Wait for the specified rouse callback (or the last one that was created in
681this coroutine). 694this coro).
682 695
683As soon as the callback is invoked (or when the callback was invoked 696As soon as the callback is invoked (or when the callback was invoked
684before C<rouse_wait>), it will return the arguments originally passed to 697before C<rouse_wait>), it will return the arguments originally passed to
685the rouse callback. 698the rouse callback.
686 699
692 705
6931; 7061;
694 707
695=head1 HOW TO WAIT FOR A CALLBACK 708=head1 HOW TO WAIT FOR A CALLBACK
696 709
697It is very common for a coroutine to wait for some callback to be 710It is very common for a coro to wait for some callback to be
698called. This occurs naturally when you use coroutines in an otherwise 711called. This occurs naturally when you use coro in an otherwise
699event-based program, or when you use event-based libraries. 712event-based program, or when you use event-based libraries.
700 713
701These typically register a callback for some event, and call that callback 714These typically register a callback for some event, and call that callback
702when the event occured. In a coroutine, however, you typically want to 715when the event occured. In a coro, however, you typically want to
703just wait for the event, simplyifying things. 716just wait for the event, simplyifying things.
704 717
705For example C<< AnyEvent->child >> registers a callback to be called when 718For example C<< AnyEvent->child >> registers a callback to be called when
706a specific child has exited: 719a specific child has exited:
707 720
708 my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); 721 my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... });
709 722
710But from withina coroutine, you often just want to write this: 723But from within a coro, you often just want to write this:
711 724
712 my $status = wait_for_child $pid; 725 my $status = wait_for_child $pid;
713 726
714Coro offers two functions specifically designed to make this easy, 727Coro offers two functions specifically designed to make this easy,
715C<Coro::rouse_cb> and C<Coro::rouse_wait>. 728C<Coro::rouse_cb> and C<Coro::rouse_wait>.
716 729
717The first function, C<rouse_cb>, generates and returns a callback that, 730The first function, C<rouse_cb>, generates and returns a callback that,
718when invoked, will save its arguments and notify the coroutine that 731when invoked, will save its arguments and notify the coro that
719created the callback. 732created the callback.
720 733
721The second function, C<rouse_wait>, waits for the callback to be called 734The second function, C<rouse_wait>, waits for the callback to be called
722(by calling C<schedule> to go to sleep) and returns the arguments 735(by calling C<schedule> to go to sleep) and returns the arguments
723originally passed to the callback. 736originally passed to the callback.
738you can roll your own, using C<schedule>: 751you can roll your own, using C<schedule>:
739 752
740 sub wait_for_child($) { 753 sub wait_for_child($) {
741 my ($pid) = @_; 754 my ($pid) = @_;
742 755
743 # store the current coroutine in $current, 756 # store the current coro in $current,
744 # and provide result variables for the closure passed to ->child 757 # and provide result variables for the closure passed to ->child
745 my $current = $Coro::current; 758 my $current = $Coro::current;
746 my ($done, $rstatus); 759 my ($done, $rstatus);
747 760
748 # pass a closure to ->child 761 # pass a closure to ->child
764 777
765=item fork with pthread backend 778=item fork with pthread backend
766 779
767When Coro is compiled using the pthread backend (which isn't recommended 780When Coro is compiled using the pthread backend (which isn't recommended
768but required on many BSDs as their libcs are completely broken), then 781but required on many BSDs as their libcs are completely broken), then
769coroutines will not survive a fork. There is no known workaround except to 782coro will not survive a fork. There is no known workaround except to
770fix your libc and use a saner backend. 783fix your libc and use a saner backend.
771 784
772=item perl process emulation ("threads") 785=item perl process emulation ("threads")
773 786
774This module is not perl-pseudo-thread-safe. You should only ever use this 787This module is not perl-pseudo-thread-safe. You should only ever use this
776future to allow per-thread schedulers, but Coro::State does not yet allow 789future to allow per-thread schedulers, but Coro::State does not yet allow
777this). I recommend disabling thread support and using processes, as having 790this). I recommend disabling thread support and using processes, as having
778the windows process emulation enabled under unix roughly halves perl 791the windows process emulation enabled under unix roughly halves perl
779performance, even when not used. 792performance, even when not used.
780 793
781=item coroutine switching not signal safe 794=item coro switching is not signal safe
782 795
783You must not switch to another coroutine from within a signal handler 796You must not switch to another coro from within a signal handler
784(only relevant with %SIG - most event libraries provide safe signals). 797(only relevant with %SIG - most event libraries provide safe signals).
785 798
786That means you I<MUST NOT> call any function that might "block" the 799That means you I<MUST NOT> call any function that might "block" the
787current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or 800current coro - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or
788anything that calls those. Everything else, including calling C<ready>, 801anything that calls those. Everything else, including calling C<ready>,
789works. 802works.
790 803
791=back 804=back
792 805

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