[ViewVC] Diff of: cvs/Coro/Coro.pm

Comparing Coro/Coro.pm (file contents):
Revision 1.136 by root, Sat Sep 22 22:59:31 2007 UTC vs.
Revision 1.202 by root, Tue Sep 30 17:12:34 2008 UTC

…		…
2		2
3	Coro - coroutine process abstraction	3	Coro - coroutine process abstraction
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use Coro;	7	use Coro;
8		8
9	async {	9	async {
10	# some asynchronous thread of execution	10	# some asynchronous thread of execution
		11	print "2\n";
		12	cede; # yield back to main
		13	print "4\n";
11	};	14	};
12		15	print "1\n";
13	# alternatively create an async coroutine like this:	16	cede; # yield to coroutine
14		17	print "3\n";
15	sub some_func : Coro {	18	cede; # and again
16	# some more async code	19
17	}	20	# use locking
18		21	use Coro::Semaphore;
19	cede;	22	my $lock = new Coro::Semaphore;
		23	my $locked;
		24
		25	$lock->down;
		26	$locked = 1;
		27	$lock->up;
20		28
21	=head1 DESCRIPTION	29	=head1 DESCRIPTION
22		30
23	This module collection manages coroutines. Coroutines are similar	31	This module collection manages coroutines. Coroutines are similar to
24	to threads but don't run in parallel at the same time even on SMP	32	threads but don't (in general) run in parallel at the same time even
25	machines. The specific flavor of coroutine used in this module also	33	on SMP machines. The specific flavor of coroutine used in this module
26	guarantees you that it will not switch between coroutines unless	34	also guarantees you that it will not switch between coroutines unless
27	necessary, at easily-identified points in your program, so locking and	35	necessary, at easily-identified points in your program, so locking and
28	parallel access are rarely an issue, making coroutine programming much	36	parallel access are rarely an issue, making coroutine programming much
29	safer than threads programming.	37	safer and easier than threads programming.
30		38
31	(Perl, however, does not natively support real threads but instead does a	39	Unlike a normal perl program, however, coroutines allow you to have
32	very slow and memory-intensive emulation of processes using threads. This	40	multiple running interpreters that share data, which is especially useful
33	is a performance win on Windows machines, and a loss everywhere else).	41	to code pseudo-parallel processes and for event-based programming, such as
		42	multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to
		43	learn more.
		44
		45	Coroutines are also useful because Perl has no support for threads (the so
		46	called "threads" that perl offers are nothing more than the (bad) process
		47	emulation coming from the Windows platform: On standard operating systems
		48	they serve no purpose whatsoever, except by making your programs slow and
		49	making them use a lot of memory. Best disable them when building perl, or
		50	aks your software vendor/distributor to do it for you).
34		51
35	In this module, coroutines are defined as "callchain + lexical variables +	52	In this module, coroutines are defined as "callchain + lexical variables +
36	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,	53	@_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain,
37	its own set of lexicals and its own set of perls most important global	54	its own set of lexicals and its own set of perls most important global
38	variables.	55	variables (see L<Coro::State> for more configuration).
39		56
40	=cut	57	=cut
41		58
42	package Coro;	59	package Coro;
43		60
…		…
50		67
51	our $idle; # idle handler	68	our $idle; # idle handler
52	our $main; # main coroutine	69	our $main; # main coroutine
53	our $current; # current coroutine	70	our $current; # current coroutine
54		71
55	our $VERSION = '3.7';	72	our $VERSION = 4.8;
56		73
57	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);	74	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub);
58	our %EXPORT_TAGS = (	75	our %EXPORT_TAGS = (
59	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	76	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
60	);	77	);
61	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));	78	our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready));
62		79
63	{
64	my @async;
65	my $init;
66
67	# this way of handling attributes simply is NOT scalable ;()
68	sub import {
69	no strict 'refs';
70
71	Coro->export_to_level (1, @_);
72
73	my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
74	*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
75	my ($package, $ref) = (shift, shift);
76	my @attrs;
77	for (@_) {
78	if ($_ eq "Coro") {
79	push @async, $ref;
80	unless ($init++) {
81	eval q{
82	sub INIT {
83	&async(pop @async) while @async;
84	}
85	};
86	}
87	} else {
88	push @attrs, $_;
89	}
90	}
91	return $old ? $old->($package, $ref, @attrs) : @attrs;
92	};
93	}
94
95	}
96
97	=over 4	80	=over 4
98		81
99	=item $main	82	=item $Coro::main
100		83
101	This coroutine represents the main program.	84	This variable stores the coroutine object that represents the main
		85	program. While you cna C<ready> it and do most other things you can do to
		86	coroutines, it is mainly useful to compare again C<$Coro::current>, to see
		87	whether you are running in the main program or not.
102		88
103	=cut	89	=cut
104		90
105	$main = new Coro;	91	$main = new Coro;
106		92
107	=item $current (or as function: current)	93	=item $Coro::current
108		94
109	The current coroutine (the last coroutine switched to). The initial value	95	The coroutine object representing the current coroutine (the last
		96	coroutine that the Coro scheduler switched to). The initial value is
110	is C<$main> (of course).	97	C<$main> (of course).
111		98
112	This variable is B<strictly> I<read-only>. It is provided for performance	99	This variable is B<strictly> I<read-only>. You can take copies of the
113	reasons. If performance is not essential you are encouraged to use the	100	value stored in it and use it as any other coroutine object, but you must
114	C<Coro::current> function instead.	101	not otherwise modify the variable itself.
115		102
116	=cut	103	=cut
117		104
118	$main->{desc} = "[main::]";	105	$main->{desc} = "[main::]";
119		106
120	# maybe some other module used Coro::Specific before...	107	# maybe some other module used Coro::Specific before...
121	$main->{specific} = $current->{specific}	108	$main->{_specific} = $current->{_specific}
122	if $current;	109	if $current;
123		110
124	_set_current $main;	111	_set_current $main;
125		112
126	sub current() { $current }	113	sub current() { $current } # [DEPRECATED]
127		114
128	=item $idle	115	=item $Coro::idle
129		116
130	A callback that is called whenever the scheduler finds no ready coroutines	117	This variable is mainly useful to integrate Coro into event loops. It is
131	to run. The default implementation prints "FATAL: deadlock detected" and	118	usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is
132	exits, because the program has no other way to continue.	119	pretty low-level functionality.
		120
		121	This variable stores a callback that is called whenever the scheduler
		122	finds no ready coroutines to run. The default implementation prints
		123	"FATAL: deadlock detected" and exits, because the program has no other way
		124	to continue.
133		125
134	This hook is overwritten by modules such as C<Coro::Timer> and	126	This hook is overwritten by modules such as C<Coro::Timer> and
135	C<Coro::Event> to wait on an external event that hopefully wake up a	127	C<Coro::AnyEvent> to wait on an external event that hopefully wake up a
136	coroutine so the scheduler can run it.	128	coroutine so the scheduler can run it.
137		129
		130	Note that the callback I<must not>, under any circumstances, block
		131	the current coroutine. Normally, this is achieved by having an "idle
		132	coroutine" that calls the event loop and then blocks again, and then
		133	readying that coroutine in the idle handler.
		134
		135	See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this
		136	technique.
		137
138	Please note that if your callback recursively invokes perl (e.g. for event	138	Please note that if your callback recursively invokes perl (e.g. for event
139	handlers), then it must be prepared to be called recursively.	139	handlers), then it must be prepared to be called recursively itself.
140		140
141	=cut	141	=cut
142		142
143	$idle = sub {	143	$idle = sub {
144	require Carp;	144	require Carp;
…		…
151	# free coroutine data and mark as destructed	151	# free coroutine data and mark as destructed
152	$self->_destroy	152	$self->_destroy
153	or return;	153	or return;
154		154
155	# call all destruction callbacks	155	# call all destruction callbacks
156	$_->(@{$self->{status}})	156	$_->(@{$self->{_status}})
157	for @{(delete $self->{destroy_cb}) \|\| []};	157	for @{(delete $self->{_on_destroy}) \|\| []};
158	}	158	}
159		159
160	# this coroutine is necessary because a coroutine	160	# this coroutine is necessary because a coroutine
161	# cannot destroy itself.	161	# cannot destroy itself.
162	my @destroy;	162	my @destroy;
…		…
171	}	171	}
172	};	172	};
173	$manager->desc ("[coro manager]");	173	$manager->desc ("[coro manager]");
174	$manager->prio (PRIO_MAX);	174	$manager->prio (PRIO_MAX);
175		175
176	# static methods. not really.
177
178	=back	176	=back
179		177
180	=head2 STATIC METHODS	178	=head2 SIMPLE COROUTINE CREATION
181
182	Static methods are actually functions that operate on the current coroutine only.
183		179
184	=over 4	180	=over 4
185		181
186	=item async { ... } [@args...]	182	=item async { ... } [@args...]
187		183
188	Create a new asynchronous coroutine and return it's coroutine object	184	Create a new coroutine and return it's coroutine object (usually
189	(usually unused). When the sub returns the new coroutine is automatically	185	unused). The coroutine will be put into the ready queue, so
		186	it will start running automatically on the next scheduler run.
		187
		188	The first argument is a codeblock/closure that should be executed in the
		189	coroutine. When it returns argument returns the coroutine is automatically
190	terminated.	190	terminated.
		191
		192	The remaining arguments are passed as arguments to the closure.
		193
		194	See the C<Coro::State::new> constructor for info about the coroutine
		195	environment in which coroutines are executed.
191		196
192	Calling C<exit> in a coroutine will do the same as calling exit outside	197	Calling C<exit> in a coroutine will do the same as calling exit outside
193	the coroutine. Likewise, when the coroutine dies, the program will exit,	198	the coroutine. Likewise, when the coroutine dies, the program will exit,
194	just as it would in the main program.	199	just as it would in the main program.
195		200
		201	If you do not want that, you can provide a default C<die> handler, or
		202	simply avoid dieing (by use of C<eval>).
		203
196	# create a new coroutine that just prints its arguments	204	Example: Create a new coroutine that just prints its arguments.
		205
197	async {	206	async {
198	print "@_\n";	207	print "@_\n";
199	} 1,2,3,4;	208	} 1,2,3,4;
200		209
201	=cut	210	=cut
…		…
207	}	216	}
208		217
209	=item async_pool { ... } [@args...]	218	=item async_pool { ... } [@args...]
210		219
211	Similar to C<async>, but uses a coroutine pool, so you should not call	220	Similar to C<async>, but uses a coroutine pool, so you should not call
212	terminate or join (although you are allowed to), and you get a coroutine	221	terminate or join on it (although you are allowed to), and you get a
213	that might have executed other code already (which can be good or bad :).	222	coroutine that might have executed other code already (which can be good
		223	or bad :).
214		224
		225	On the plus side, this function is faster than creating (and destroying)
		226	a completely new coroutine, so if you need a lot of generic coroutines in
		227	quick successsion, use C<async_pool>, not C<async>.
		228
215	Also, the block is executed in an C<eval> context and a warning will be	229	The code block is executed in an C<eval> context and a warning will be
216	issued in case of an exception instead of terminating the program, as	230	issued in case of an exception instead of terminating the program, as
217	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>	231	C<async> does. As the coroutine is being reused, stuff like C<on_destroy>
218	will not work in the expected way, unless you call terminate or cancel,	232	will not work in the expected way, unless you call terminate or cancel,
219	which somehow defeats the purpose of pooling.	233	which somehow defeats the purpose of pooling (but is fine in the
		234	exceptional case).
220		235
221	The priority will be reset to C<0> after each job, otherwise the coroutine	236	The priority will be reset to C<0> after each run, tracing will be
222	will be re-used "as-is".	237	disabled, the description will be reset and the default output filehandle
		238	gets restored, so you can change all these. Otherwise the coroutine will
		239	be re-used "as-is": most notably if you change other per-coroutine global
		240	stuff such as C<$/> you I<must needs> to revert that change, which is most
		241	simply done by using local as in: C< local $/ >.
223		242
224	The pool size is limited to 8 idle coroutines (this can be adjusted by	243	The pool size is limited to C<8> idle coroutines (this can be adjusted by
225	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as	244	changing $Coro::POOL_SIZE), and there can be as many non-idle coros as
226	required.	245	required.
227		246
228	If you are concerned about pooled coroutines growing a lot because a	247	If you are concerned about pooled coroutines growing a lot because a
229	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool	248	single C<async_pool> used a lot of stackspace you can e.g. C<async_pool
230	{ terminate }> once per second or so to slowly replenish the pool. In	249	{ terminate }> once per second or so to slowly replenish the pool. In
231	addition to that, when the stacks used by a handler grows larger than 16kb	250	addition to that, when the stacks used by a handler grows larger than 16kb
232	(adjustable with $Coro::POOL_RSS) it will also exit.	251	(adjustable via $Coro::POOL_RSS) it will also be destroyed.
233		252
234	=cut	253	=cut
235		254
236	our $POOL_SIZE = 8;	255	our $POOL_SIZE = 8;
237	our $POOL_RSS = 16 * 1024;	256	our $POOL_RSS = 16 * 1024;
…		…
248	_pool_2 $cb;	267	_pool_2 $cb;
249	&schedule;	268	&schedule;
250	}	269	}
251	};	270	};
252		271
		272	if ($@) {
253	last if $@ eq "\3terminate\2\n";	273	last if $@ eq "\3async_pool terminate\2\n";
254	warn $@ if $@;	274	warn $@;
		275	}
255	}	276	}
256	}	277	}
257		278
258	sub async_pool(&@) {	279	sub async_pool(&@) {
259	# this is also inlined into the unlock_scheduler	280	# this is also inlined into the unlock_scheduler
…		…
263	$coro->ready;	284	$coro->ready;
264		285
265	$coro	286	$coro
266	}	287	}
267		288
		289	=back
		290
		291	=head2 STATIC METHODS
		292
		293	Static methods are actually functions that operate on the current coroutine.
		294
		295	=over 4
		296
268	=item schedule	297	=item schedule
269		298
270	Calls the scheduler. Please note that the current coroutine will not be put	299	Calls the scheduler. The scheduler will find the next coroutine that is
		300	to be run from the ready queue and switches to it. The next coroutine
		301	to be run is simply the one with the highest priority that is longest
		302	in its ready queue. If there is no coroutine ready, it will clal the
		303	C<$Coro::idle> hook.
		304
		305	Please note that the current coroutine will I<not> be put into the ready
271	into the ready queue, so calling this function usually means you will	306	queue, so calling this function usually means you will never be called
272	never be called again unless something else (e.g. an event handler) calls	307	again unless something else (e.g. an event handler) calls C<< ->ready >>,
273	ready.	308	thus waking you up.
		309
		310	This makes C<schedule> I<the> generic method to use to block the current
		311	coroutine and wait for events: first you remember the current coroutine in
		312	a variable, then arrange for some callback of yours to call C<< ->ready
		313	>> on that once some event happens, and last you call C<schedule> to put
		314	yourself to sleep. Note that a lot of things can wake your coroutine up,
		315	so you need to check whether the event indeed happened, e.g. by storing the
		316	status in a variable.
274		317
275	The canonical way to wait on external events is this:	318	The canonical way to wait on external events is this:
276		319
277	{	320	{
278	# remember current coroutine	321	# remember current coroutine
…		…
291	Coro::schedule while $current;	334	Coro::schedule while $current;
292	}	335	}
293		336
294	=item cede	337	=item cede
295		338
296	"Cede" to other coroutines. This function puts the current coroutine into the	339	"Cede" to other coroutines. This function puts the current coroutine into
297	ready queue and calls C<schedule>, which has the effect of giving up the	340	the ready queue and calls C<schedule>, which has the effect of giving
298	current "timeslice" to other coroutines of the same or higher priority.	341	up the current "timeslice" to other coroutines of the same or higher
		342	priority. Once your coroutine gets its turn again it will automatically be
		343	resumed.
299		344
300	Returns true if at least one coroutine switch has happened.	345	This function is often called C<yield> in other languages.
301		346
302	=item Coro::cede_notself	347	=item Coro::cede_notself
303		348
304	Works like cede, but is not exported by default and will cede to any	349	Works like cede, but is not exported by default and will cede to I<any>
305	coroutine, regardless of priority, once.	350	coroutine, regardless of priority. This is useful sometimes to ensure
306		351	progress is made.
307	Returns true if at least one coroutine switch has happened.
308		352
309	=item terminate [arg...]	353	=item terminate [arg...]
310		354
311	Terminates the current coroutine with the given status values (see L<cancel>).	355	Terminates the current coroutine with the given status values (see L<cancel>).
		356
		357	=item killall
		358
		359	Kills/terminates/cancels all coroutines except the currently running
		360	one. This is useful after a fork, either in the child or the parent, as
		361	usually only one of them should inherit the running coroutines.
		362
		363	Note that while this will try to free some of the main programs resources,
		364	you cannot free all of them, so if a coroutine that is not the main
		365	program calls this function, there will be some one-time resource leak.
312		366
313	=cut	367	=cut
314		368
315	sub terminate {	369	sub terminate {
316	$current->cancel (@_);	370	$current->cancel (@_);
317	}	371	}
318		372
		373	sub killall {
		374	for (Coro::State::list) {
		375	$_->cancel
		376	if $_ != $current && UNIVERSAL::isa $_, "Coro";
		377	}
		378	}
		379
319	=back	380	=back
320		381
321	# dynamic methods
322
323	=head2 COROUTINE METHODS	382	=head2 COROUTINE METHODS
324		383
325	These are the methods you can call on coroutine objects.	384	These are the methods you can call on coroutine objects (or to create
		385	them).
326		386
327	=over 4	387	=over 4
328		388
329	=item new Coro \&sub [, @args...]	389	=item new Coro \&sub [, @args...]
330		390
331	Create a new coroutine and return it. When the sub returns the coroutine	391	Create a new coroutine and return it. When the sub returns, the coroutine
332	automatically terminates as if C<terminate> with the returned values were	392	automatically terminates as if C<terminate> with the returned values were
333	called. To make the coroutine run you must first put it into the ready queue	393	called. To make the coroutine run you must first put it into the ready
334	by calling the ready method.	394	queue by calling the ready method.
335		395
336	See C<async> for additional discussion.	396	See C<async> and C<Coro::State::new> for additional info about the
		397	coroutine environment.
337		398
338	=cut	399	=cut
339		400
340	sub _run_coro {	401	sub _run_coro {
341	terminate &{+shift};	402	terminate &{+shift};
…		…
347	$class->SUPER::new (\&_run_coro, @_)	408	$class->SUPER::new (\&_run_coro, @_)
348	}	409	}
349		410
350	=item $success = $coroutine->ready	411	=item $success = $coroutine->ready
351		412
352	Put the given coroutine into the ready queue (according to it's priority)	413	Put the given coroutine into the end of its ready queue (there is one
353	and return true. If the coroutine is already in the ready queue, do nothing	414	queue for each priority) and return true. If the coroutine is already in
354	and return false.	415	the ready queue, do nothing and return false.
		416
		417	This ensures that the scheduler will resume this coroutine automatically
		418	once all the coroutines of higher priority and all coroutines of the same
		419	priority that were put into the ready queue earlier have been resumed.
355		420
356	=item $is_ready = $coroutine->is_ready	421	=item $is_ready = $coroutine->is_ready
357		422
358	Return wether the coroutine is currently the ready queue or not,	423	Return whether the coroutine is currently the ready queue or not,
359		424
360	=item $coroutine->cancel (arg...)	425	=item $coroutine->cancel (arg...)
361		426
362	Terminates the given coroutine and makes it return the given arguments as	427	Terminates the given coroutine and makes it return the given arguments as
363	status (default: the empty list). Never returns if the coroutine is the	428	status (default: the empty list). Never returns if the coroutine is the
…		…
365		430
366	=cut	431	=cut
367		432
368	sub cancel {	433	sub cancel {
369	my $self = shift;	434	my $self = shift;
370	$self->{status} = [@_];	435	$self->{_status} = [@_];
371		436
372	if ($current == $self) {	437	if ($current == $self) {
373	push @destroy, $self;	438	push @destroy, $self;
374	$manager->ready;	439	$manager->ready;
375	&schedule while 1;	440	&schedule while 1;
…		…
379	}	444	}
380		445
381	=item $coroutine->join	446	=item $coroutine->join
382		447
383	Wait until the coroutine terminates and return any values given to the	448	Wait until the coroutine terminates and return any values given to the
384	C<terminate> or C<cancel> functions. C<join> can be called multiple times	449	C<terminate> or C<cancel> functions. C<join> can be called concurrently
385	from multiple coroutine.	450	from multiple coroutines, and all will be resumed and given the status
		451	return once the C<$coroutine> terminates.
386		452
387	=cut	453	=cut
388		454
389	sub join {	455	sub join {
390	my $self = shift;	456	my $self = shift;
391		457
392	unless ($self->{status}) {	458	unless ($self->{_status}) {
393	my $current = $current;	459	my $current = $current;
394		460
395	push @{$self->{destroy_cb}}, sub {	461	push @{$self->{_on_destroy}}, sub {
396	$current->ready;	462	$current->ready;
397	undef $current;	463	undef $current;
398	};	464	};
399		465
400	&schedule while $current;	466	&schedule while $current;
401	}	467	}
402		468
403	wantarray ? @{$self->{status}} : $self->{status}[0];	469	wantarray ? @{$self->{_status}} : $self->{_status}[0];
404	}	470	}
405		471
406	=item $coroutine->on_destroy (\&cb)	472	=item $coroutine->on_destroy (\&cb)
407		473
408	Registers a callback that is called when this coroutine gets destroyed,	474	Registers a callback that is called when this coroutine gets destroyed,
409	but before it is joined. The callback gets passed the terminate arguments,	475	but before it is joined. The callback gets passed the terminate arguments,
410	if any.	476	if any, and I<must not> die, under any circumstances.
411		477
412	=cut	478	=cut
413		479
414	sub on_destroy {	480	sub on_destroy {
415	my ($self, $cb) = @_;	481	my ($self, $cb) = @_;
416		482
417	push @{ $self->{destroy_cb} }, $cb;	483	push @{ $self->{_on_destroy} }, $cb;
418	}	484	}
419		485
420	=item $oldprio = $coroutine->prio ($newprio)	486	=item $oldprio = $coroutine->prio ($newprio)
421		487
422	Sets (or gets, if the argument is missing) the priority of the	488	Sets (or gets, if the argument is missing) the priority of the
…		…
447	=item $olddesc = $coroutine->desc ($newdesc)	513	=item $olddesc = $coroutine->desc ($newdesc)
448		514
449	Sets (or gets in case the argument is missing) the description for this	515	Sets (or gets in case the argument is missing) the description for this
450	coroutine. This is just a free-form string you can associate with a coroutine.	516	coroutine. This is just a free-form string you can associate with a coroutine.
451		517
		518	This method simply sets the C<< $coroutine->{desc} >> member to the given string. You
		519	can modify this member directly if you wish.
		520
		521	=item $coroutine->throw ([$scalar])
		522
		523	If C<$throw> is specified and defined, it will be thrown as an exception
		524	inside the coroutine at the next convinient point in time (usually after
		525	it gains control at the next schedule/transfer/cede). Otherwise clears the
		526	exception object.
		527
		528	The exception object will be thrown "as is" with the specified scalar in
		529	C<$@>, i.e. if it is a string, no line number or newline will be appended
		530	(unlike with C<die>).
		531
		532	This can be used as a softer means than C<cancel> to ask a coroutine to
		533	end itself, although there is no guarentee that the exception will lead to
		534	termination, and if the exception isn't caught it might well end the whole
		535	program.
		536
452	=cut	537	=cut
453		538
454	sub desc {	539	sub desc {
455	my $old = $_[0]{desc};	540	my $old = $_[0]{desc};
456	$_[0]{desc} = $_[1] if @_ > 1;	541	$_[0]{desc} = $_[1] if @_ > 1;
…		…
464	=over 4	549	=over 4
465		550
466	=item Coro::nready	551	=item Coro::nready
467		552
468	Returns the number of coroutines that are currently in the ready state,	553	Returns the number of coroutines that are currently in the ready state,
469	i.e. that can be switched to. The value C<0> means that the only runnable	554	i.e. that can be switched to by calling C<schedule> directory or
		555	indirectly. The value C<0> means that the only runnable coroutine is the
470	coroutine is the currently running one, so C<cede> would have no effect,	556	currently running one, so C<cede> would have no effect, and C<schedule>
471	and C<schedule> would cause a deadlock unless there is an idle handler	557	would cause a deadlock unless there is an idle handler that wakes up some
472	that wakes up some coroutines.	558	coroutines.
473		559
474	=item my $guard = Coro::guard { ... }	560	=item my $guard = Coro::guard { ... }
475		561
476	This creates and returns a guard object. Nothing happens until the object	562	This creates and returns a guard object. Nothing happens until the object
477	gets destroyed, in which case the codeblock given as argument will be	563	gets destroyed, in which case the codeblock given as argument will be
…		…
506		592
507		593
508	=item unblock_sub { ... }	594	=item unblock_sub { ... }
509		595
510	This utility function takes a BLOCK or code reference and "unblocks" it,	596	This utility function takes a BLOCK or code reference and "unblocks" it,
511	returning the new coderef. This means that the new coderef will return	597	returning a new coderef. Unblocking means that calling the new coderef
512	immediately without blocking, returning nothing, while the original code	598	will return immediately without blocking, returning nothing, while the
513	ref will be called (with parameters) from within its own coroutine.	599	original code ref will be called (with parameters) from within another
		600	coroutine.
514		601
515	The reason this function exists is that many event libraries (such as the	602	The reason this function exists is that many event libraries (such as the
516	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form	603	venerable L<Event\|Event> module) are not coroutine-safe (a weaker form
517	of thread-safety). This means you must not block within event callbacks,	604	of thread-safety). This means you must not block within event callbacks,
518	otherwise you might suffer from crashes or worse.	605	otherwise you might suffer from crashes or worse. The only event library
		606	currently known that is safe to use without C<unblock_sub> is L<EV>.
519		607
520	This function allows your callbacks to block by executing them in another	608	This function allows your callbacks to block by executing them in another
521	coroutine where it is safe to block. One example where blocking is handy	609	coroutine where it is safe to block. One example where blocking is handy
522	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to	610	is when you use the L<Coro::AIO\|Coro::AIO> functions to save results to
523	disk.	611	disk, for example.
524		612
525	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when	613	In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when
526	creating event callbacks that want to block.	614	creating event callbacks that want to block.
		615
		616	If your handler does not plan to block (e.g. simply sends a message to
		617	another coroutine, or puts some other coroutine into the ready queue),
		618	there is no reason to use C<unblock_sub>.
		619
		620	Note that you also need to use C<unblock_sub> for any other callbacks that
		621	are indirectly executed by any C-based event loop. For example, when you
		622	use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it
		623	provides callbacks that are the result of some event callback, then you
		624	must not block either, or use C<unblock_sub>.
527		625
528	=cut	626	=cut
529		627
530	our @unblock_queue;	628	our @unblock_queue;
531		629
…		…
563		661
564	1;	662	1;
565		663
566	=head1 BUGS/LIMITATIONS	664	=head1 BUGS/LIMITATIONS
567		665
568	- you must make very sure that no coro is still active on global
569	destruction. very bad things might happen otherwise (usually segfaults).
570
571	- this module is not thread-safe. You should only ever use this module	666	This module is not perl-pseudo-thread-safe. You should only ever use this
572	from the same thread (this requirement might be loosened in the future	667	module from the same thread (this requirement might be removed in the
573	to allow per-thread schedulers, but Coro::State does not yet allow	668	future to allow per-thread schedulers, but Coro::State does not yet allow
574	this).	669	this). I recommend disabling thread support and using processes, as this
		670	is much faster and uses less memory.
575		671
576	=head1 SEE ALSO	672	=head1 SEE ALSO
577		673
		674	Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
		675
		676	Debugging: L<Coro::Debug>.
		677
578	Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>.	678	Support/Utility: L<Coro::Specific>, L<Coro::Util>.
579		679
580	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.	680	Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>.
581		681
582	Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>.	682	IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>.
583		683
584	Embedding: L<Coro:MakeMaker>	684	Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>.
		685
		686	XS API: L<Coro::MakeMaker>.
		687
		688	Low level Configuration, Coroutine Environment: L<Coro::State>.
585		689
586	=head1 AUTHOR	690	=head1 AUTHOR
587		691
588	Marc Lehmann <schmorp@schmorp.de>	692	Marc Lehmann <schmorp@schmorp.de>
589	http://home.schmorp.de/	693	http://home.schmorp.de/

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Comparing Coro/Coro.pm (file contents): Revision 1.136 by root, Sat Sep 22 22:59:31 2007 UTC vs. Revision 1.202 by root, Tue Sep 30 17:12:34 2008 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.136 by root, Sat Sep 22 22:59:31 2007 UTC vs.
Revision 1.202 by root, Tue Sep 30 17:12:34 2008 UTC