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

Comparing Coro/Coro.pm (file contents):
Revision 1.282 by root, Sun Dec 26 16:23:51 2010 UTC vs.
Revision 1.297 by root, Thu May 12 23:55:39 2011 UTC

…		…
40	points in your program, so locking and parallel access are rarely an	40	points in your program, so locking and parallel access are rarely an
41	issue, making thread programming much safer and easier than using other	41	issue, making thread programming much safer and easier than using other
42	thread models.	42	thread models.
43		43
44	Unlike the so-called "Perl threads" (which are not actually real threads	44	Unlike the so-called "Perl threads" (which are not actually real threads
45	but only the windows process emulation (see section of same name for more	45	but only the windows process emulation (see section of same name for
46	details) ported to unix, and as such act as processes), Coro provides	46	more details) ported to UNIX, and as such act as processes), Coro
47	a full shared address space, which makes communication between threads	47	provides a full shared address space, which makes communication between
48	very easy. And Coro's threads are fast, too: disabling the Windows	48	threads very easy. And coro threads are fast, too: disabling the Windows
49	process emulation code in your perl and using Coro can easily result in	49	process emulation code in your perl and using Coro can easily result in
50	a two to four times speed increase for your programs. A parallel matrix	50	a two to four times speed increase for your programs. A parallel matrix
51	multiplication benchmark runs over 300 times faster on a single core than	51	multiplication benchmark (very communication-intensive) runs over 300
52	perl's pseudo-threads on a quad core using all four cores.	52	times faster on a single core than perls pseudo-threads on a quad core
		53	using all four cores.
53		54
54	Coro achieves that by supporting multiple running interpreters that share	55	Coro achieves that by supporting multiple running interpreters that share
55	data, which is especially useful to code pseudo-parallel processes and	56	data, which is especially useful to code pseudo-parallel processes and
56	for event-based programming, such as multiple HTTP-GET requests running	57	for event-based programming, such as multiple HTTP-GET requests running
57	concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro	58	concurrently. See L<Coro::AnyEvent> to learn more on how to integrate Coro
…		…
63	variables (see L<Coro::State> for more configuration and background info).	64	variables (see L<Coro::State> for more configuration and background info).
64		65
65	See also the C<SEE ALSO> section at the end of this document - the Coro	66	See also the C<SEE ALSO> section at the end of this document - the Coro
66	module family is quite large.	67	module family is quite large.
67		68
		69	=head1 CORO THREAD LIFE CYCLE
		70
		71	During the long and exciting (or not) life of a coro thread, it goes
		72	through a number of states:
		73
		74	=over 4
		75
		76	=item 1. Creation
		77
		78	The first thing in the life of a coro thread is it's creation -
		79	obviously. The typical way to create a thread is to call the C<async
		80	BLOCK> function:
		81
		82	async {
		83	# thread code goes here
		84	};
		85
		86	You can also pass arguments, which are put in C<@_>:
		87
		88	async {
		89	print $_[1]; # prints 2
		90	} 1, 2, 3;
		91
		92	This creates a new coro thread and puts it into the ready queue, meaning
		93	it will run as soon as the CPU is free for it.
		94
		95	C<async> will return a Coro object - you can store this for future
		96	reference or ignore it - a thread that is running, ready to run or waiting
		97	for some event is alive on it's own.
		98
		99	Another way to create a thread is to call the C<new> constructor with a
		100	code-reference:
		101
		102	new Coro sub {
		103	# thread code goes here
		104	}, @optional_arguments;
		105
		106	This is quite similar to calling C<async>, but the important difference is
		107	that the new thread is not put into the ready queue, so the thread will
		108	not run until somebody puts it there. C<async> is, therefore, identical to
		109	this sequence:
		110
		111	my $coro = new Coro sub {
		112	# thread code goes here
		113	};
		114	$coro->ready;
		115	return $coro;
		116
		117	=item 2. Startup
		118
		119	When a new coro thread is created, only a copy of the code reference
		120	and the arguments are stored, no extra memory for stacks and so on is
		121	allocated, keeping the coro thread in a low-memory state.
		122
		123	Only when it actually starts executing will all the resources be finally
		124	allocated.
		125
		126	The optional arguments specified at coro creation are available in C<@_>,
		127	similar to function calls.
		128
		129	=item 3. Running / Blocking
		130
		131	A lot can happen after the coro thread has started running. Quite usually,
		132	it will not run to the end in one go (because you could use a function
		133	instead), but it will give up the CPU regularly because it waits for
		134	external events.
		135
		136	As long as a coro thread runs, its Coro object is available in the global
		137	variable C<$Coro::current>.
		138
		139	The low-level way to give up the CPU is to call the scheduler, which
		140	selects a new coro thread to run:
		141
		142	Coro::schedule;
		143
		144	Since running threads are not in the ready queue, calling the scheduler
		145	without doing anything else will block the coro thread forever - you need
		146	to arrange either for the coro to put woken up (readied) by some other
		147	event or some other thread, or you can put it into the ready queue before
		148	scheduling:
		149
		150	# this is exactly what Coro::cede does
		151	$Coro::current->ready;
		152	Coro::schedule;
		153
		154	All the higher-level synchronisation methods (Coro::Semaphore,
		155	Coro::rouse_*...) are actually implemented via C<< ->ready >> and C<<
		156	Coro::schedule >>.
		157
		158	While the coro thread is running it also might get assigned a C-level
		159	thread, or the C-level thread might be unassigned from it, as the Coro
		160	runtime wishes. A C-level thread needs to be assigned when your perl
		161	thread calls into some C-level function and that function in turn calls
		162	perl and perl then wants to switch coroutines. This happens most often
		163	when you run an event loop and block in the callback, or when perl
		164	itself calls some function such as C<AUTOLOAD> or methods via the C<tie>
		165	mechanism.
		166
		167	=item 4. Termination
		168
		169	Many threads actually terminate after some time. There are a number of
		170	ways to terminate a coro thread, the simplest is returning from the
		171	top-level code reference:
		172
		173	async {
		174	# after returning from here, the coro thread is terminated
		175	};
		176
		177	async {
		178	return if 0.5 < rand; # terminate a little earlier, maybe
		179	print "got a chance to print this\n";
		180	# or here
		181	};
		182
		183	Any values returned from the coroutine can be recovered using C<< ->join
		184	>>:
		185
		186	my $coro = async {
		187	"hello, world\n" # return a string
		188	};
		189
		190	my $hello_world = $coro->join;
		191
		192	print $hello_world;
		193
		194	Another way to terminate is to call C<< Coro::terminate >>, which at any
		195	subroutine call nesting level:
		196
		197	async {
		198	Coro::terminate "return value 1", "return value 2";
		199	};
		200
		201	And yet another way is to C<< ->cancel >> (or C<< ->safe_cancel >>) the
		202	coro thread from another thread:
		203
		204	my $coro = async {
		205	exit 1;
		206	};
		207
		208	$coro->cancel; # also accepts values for ->join to retrieve
		209
		210	Cancellation I<can> be dangerous - it's a bit like calling C<exit> without
		211	actually exiting, and might leave C libraries and XS modules in a weird
		212	state. Unlike other thread implementations, however, Coro is exceptionally
		213	safe with regards to cancellation, as perl will always be in a consistent
		214	state, and for those cases where you want to do truly marvellous things
		215	with your coro while it is being cancelled - that is, make sure all
		216	cleanup code is executed from the thread being cancelled - there is even a
		217	C<< ->safe_cancel >> method.
		218
		219	So, cancelling a thread that runs in an XS event loop might not be the
		220	best idea, but any other combination that deals with perl only (cancelling
		221	when a thread is in a C<tie> method or an C<AUTOLOAD> for example) is
		222	safe.
		223
		224	Lastly, a coro thread object that isn't referenced is C<< ->cancel >>'ed
		225	automatically - just like other objects in Perl. This is not such a common
		226	case, however - a running thread is referencedy b C<$Coro::current>, a
		227	thread ready to run is referenced by the ready queue, a thread waiting
		228	on a lock or semaphore is referenced by being in some wait list and so
		229	on. But a thread that isn't in any of those queues gets cancelled:
		230
		231	async {
		232	schedule; # cede to other coros, don't go into the ready queue
		233	};
		234
		235	cede;
		236	# now the async above is destroyed, as it is not referenced by anything.
		237
		238	=item 5. Cleanup
		239
		240	Threads will allocate various resources. Most but not all will be returned
		241	when a thread terminates, during clean-up.
		242
		243	Cleanup is quite similar to throwing an uncaught exception: perl will
		244	work it's way up through all subroutine calls and blocks. On it's way, it
		245	will release all C<my> variables, undo all C<local>'s and free any other
		246	resources truly local to the thread.
		247
		248	So, a common way to free resources is to keep them referenced only by my
		249	variables:
		250
		251	async {
		252	my $big_cache = new Cache ...;
		253	};
		254
		255	If there are no other references, then the C<$big_cache> object will be
		256	freed when the thread terminates, regardless of how it does so.
		257
		258	What it does C<NOT> do is unlock any Coro::Semaphores or similar
		259	resources, but that's where the C<guard> methods come in handy:
		260
		261	my $sem = new Coro::Semaphore;
		262
		263	async {
		264	my $lock_guard = $sem->guard;
		265	# if we reutrn, or die or get cancelled, here,
		266	# then the semaphore will be "up"ed.
		267	};
		268
		269	The C<Guard::guard> function comes in handy for any custom cleanup you
		270	might want to do (but you cannot switch to other coroutines form those
		271	code blocks):
		272
		273	async {
		274	my $window = new Gtk2::Window "toplevel";
		275	# The window will not be cleaned up automatically, even when $window
		276	# gets freed, so use a guard to ensure it's destruction
		277	# in case of an error:
		278	my $window_guard = Guard::guard { $window->destroy };
		279
		280	# we are safe here
		281	};
		282
		283	Last not least, C<local> can often be handy, too, e.g. when temporarily
		284	replacing the coro thread description:
		285
		286	sub myfunction {
		287	local $Coro::current->{desc} = "inside myfunction(@_)";
		288
		289	# if we return or die here, the description will be restored
		290	}
		291
		292	=item 6. Viva La Zombie Muerte
		293
		294	Even after a thread has terminated and cleaned up its resources, the Coro
		295	object still is there and stores the return values of the thread.
		296
		297	The means the Coro object gets freed automatically when the thread has
		298	terminated and cleaned up and there arenot other references.
		299
		300	If there are, the Coro object will stay around, and you can call C<<
		301	->join >> as many times as you wish to retrieve the result values:
		302
		303	async {
		304	print "hi\n";
		305	1
		306	};
		307
		308	# run the async above, and free everything before returning
		309	# from Coro::cede:
		310	Coro::cede;
		311
		312	{
		313	my $coro = async {
		314	print "hi\n";
		315	1
		316	};
		317
		318	# run the async above, and clean up, but do not free the coro
		319	# object:
		320	Coro::cede;
		321
		322	# optionally retrieve the result values
		323	my @results = $coro->join;
		324
		325	# now $coro goes out of scope, and presumably gets freed
		326	};
		327
		328	=back
		329
68	=cut	330	=cut
69		331
70	package Coro;	332	package Coro;
71		333
72	use common::sense;	334	use common::sense;
…		…
81		343
82	our $idle; # idle handler	344	our $idle; # idle handler
83	our $main; # main coro	345	our $main; # main coro
84	our $current; # current coro	346	our $current; # current coro
85		347
86	our $VERSION = 5.25;	348	our $VERSION = 5.372;
87		349
88	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait);	350	our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub rouse_cb rouse_wait);
89	our %EXPORT_TAGS = (	351	our %EXPORT_TAGS = (
90	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],	352	prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)],
91	);	353	);
…		…
131		393
132	The default implementation dies with "FATAL: deadlock detected.", followed	394	The default implementation dies with "FATAL: deadlock detected.", followed
133	by a thread listing, because the program has no other way to continue.	395	by a thread listing, because the program has no other way to continue.
134		396
135	This hook is overwritten by modules such as C<Coro::EV> and	397	This hook is overwritten by modules such as C<Coro::EV> and
136	C<Coro::AnyEvent> to wait on an external event that hopefully wake up a	398	C<Coro::AnyEvent> to wait on an external event that hopefully wakes up a
137	coro so the scheduler can run it.	399	coro so the scheduler can run it.
138		400
139	See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique.	401	See L<Coro::EV> or L<Coro::AnyEvent> for examples of using this technique.
140		402
141	=cut	403	=cut
…		…
152	our @destroy;	414	our @destroy;
153	our $manager;	415	our $manager;
154		416
155	$manager = new Coro sub {	417	$manager = new Coro sub {
156	while () {	418	while () {
157	Coro::State::cancel shift @destroy	419	_destroy shift @destroy
158	while @destroy;	420	while @destroy;
159		421
160	&schedule;	422	&schedule;
161	}	423	}
162	};	424	};
…		…
296	coro, regardless of priority. This is useful sometimes to ensure	558	coro, regardless of priority. This is useful sometimes to ensure
297	progress is made.	559	progress is made.
298		560
299	=item terminate [arg...]	561	=item terminate [arg...]
300		562
301	Terminates the current coro with the given status values (see L<cancel>).	563	Terminates the current coro with the given status values (see
		564	L<cancel>). The values will not be copied, but referenced directly.
302		565
303	=item Coro::on_enter BLOCK, Coro::on_leave BLOCK	566	=item Coro::on_enter BLOCK, Coro::on_leave BLOCK
304		567
305	These function install enter and leave winders in the current scope. The	568	These function install enter and leave winders in the current scope. The
306	enter block will be executed when on_enter is called and whenever the	569	enter block will be executed when on_enter is called and whenever the
…		…
462	To avoid this, it is best to put a suspended coro into the ready queue	725	To avoid this, it is best to put a suspended coro into the ready queue
463	unconditionally, as every synchronisation mechanism must protect itself	726	unconditionally, as every synchronisation mechanism must protect itself
464	against spurious wakeups, and the one in the Coro family certainly do	727	against spurious wakeups, and the one in the Coro family certainly do
465	that.	728	that.
466		729
		730	=item $state->is_new
		731
		732	Returns true iff this Coro object is "new", i.e. has never been run
		733	yet. Those states basically consist of only the code reference to call and
		734	the arguments, but consumes very little other resources. New states will
		735	automatically get assigned a perl interpreter when they are transfered to.
		736
		737	=item $state->is_zombie
		738
		739	Returns true iff the Coro object has been cancelled, i.e.
		740	it's resources freed because they were C<cancel>'ed, C<terminate>'d,
		741	C<safe_cancel>'ed or simply went out of scope.
		742
		743	The name "zombie" stems from UNIX culture, where a process that has
		744	exited and only stores and exit status and no other resources is called a
		745	"zombie".
		746
467	=item $is_ready = $coro->is_ready	747	=item $is_ready = $coro->is_ready
468		748
469	Returns true iff the Coro object is in the ready queue. Unless the Coro	749	Returns true iff the Coro object is in the ready queue. Unless the Coro
470	object gets destroyed, it will eventually be scheduled by the scheduler.	750	object gets destroyed, it will eventually be scheduled by the scheduler.
471		751
…		…
480	Returns true iff this Coro object has been suspended. Suspended Coros will	760	Returns true iff this Coro object has been suspended. Suspended Coros will
481	not ever be scheduled.	761	not ever be scheduled.
482		762
483	=item $coro->cancel (arg...)	763	=item $coro->cancel (arg...)
484		764
485	Terminates the given Coro and makes it return the given arguments as	765	Terminates the given Coro thread and makes it return the given arguments as
486	status (default: the empty list). Never returns if the Coro is the	766	status (default: an empty list). Never returns if the Coro is the
487	current Coro.	767	current Coro.
488		768
489	=cut	769	This is a rather brutal way to free a coro, with some limitations - if
		770	the thread is inside a C callback that doesn't expect to be canceled,
		771	bad things can happen, or if the cancelled thread insists on running
		772	complicated cleanup handlers that rely on it'S thread context, things will
		773	not work.
490		774
491	sub cancel {	775	Any cleanup code being run (e.g. from C<guard> blocks) will be run without
492	my $self = shift;	776	a thread context, and is not allowed to switch to other threads. On the
		777	plus side, C<< ->cancel >> will always clean up the thread, no matter
		778	what. If your cleanup code is complex or you want to avoid cancelling a
		779	C-thread that doesn't know how to clean up itself, it can be better to C<<
		780	->throw >> an exception, or use C<< ->safe_cancel >>.
493		781
494	if ($current == $self) {	782	The arguments to C<< ->cancel >> are not copied, but instead will
495	terminate @_;	783	be referenced directly (e.g. if you pass C<$var> and after the call
496	} else {	784	change that variable, then you might change the return values passed to
497	$self->{_status} = [@_];	785	e.g. C<join>, so don't do that).
498	Coro::State::cancel $self;	786
		787	The resources of the Coro are usually freed (or destructed) before this
		788	call returns, but this can be delayed for an indefinite amount of time, as
		789	in some cases the manager thread has to run first to actually destruct the
		790	Coro object.
		791
		792	=item $coro->safe_cancel ($arg...)
		793
		794	Works mostly like C<< ->cancel >>, but is inherently "safer", and
		795	consequently, can fail with an exception in cases the thread is not in a
		796	cancellable state.
		797
		798	This method works a bit like throwing an exception that cannot be caught
		799	- specifically, it will clean up the thread from within itself, so
		800	all cleanup handlers (e.g. C<guard> blocks) are run with full thread
		801	context and can block if they wish. The downside is that there is no
		802	guarantee that the thread can be cancelled when you call this method, and
		803	therefore, it might fail. It is also considerably slower than C<cancel> or
		804	C<terminate>.
		805
		806	A thread is in a safe-cancellable state if it either hasn't been run yet,
		807	or it has no C context attached and is inside an SLF function.
		808
		809	The latter two basically mean that the thread isn't currently inside a
		810	perl callback called from some C function (usually via some XS modules)
		811	and isn't currently executing inside some C function itself (via Coro's XS
		812	API).
		813
		814	This call returns true when it could cancel the thread, or croaks with an
		815	error otherwise (i.e. it either returns true or doesn't return at all).
		816
		817	Why the weird interface? Well, there are two common models on how and
		818	when to cancel things. In the first, you have the expectation that your
		819	coro thread can be cancelled when you want to cancel it - if the thread
		820	isn't cancellable, this would be a bug somewhere, so C<< ->safe_cancel >>
		821	croaks to notify of the bug.
		822
		823	In the second model you sometimes want to ask nicely to cancel a thread,
		824	but if it's not a good time, well, then don't cancel. This can be done
		825	relatively easy like this:
		826
		827	if (! eval { $coro->safe_cancel }) {
		828	warn "unable to cancel thread: $@";
499	}	829	}
500	}	830
		831	However, what you never should do is first try to cancel "safely" and
		832	if that fails, cancel the "hard" way with C<< ->cancel >>. That makes
		833	no sense: either you rely on being able to execute cleanup code in your
		834	thread context, or you don't. If you do, then C<< ->safe_cancel >> is the
		835	only way, and if you don't, then C<< ->cancel >> is always faster and more
		836	direct.
501		837
502	=item $coro->schedule_to	838	=item $coro->schedule_to
503		839
504	Puts the current coro to sleep (like C<Coro::schedule>), but instead	840	Puts the current coro to sleep (like C<Coro::schedule>), but instead
505	of continuing with the next coro from the ready queue, always switch to	841	of continuing with the next coro from the ready queue, always switch to
…		…
524	inside the coro at the next convenient point in time. Otherwise	860	inside the coro at the next convenient point in time. Otherwise
525	clears the exception object.	861	clears the exception object.
526		862
527	Coro will check for the exception each time a schedule-like-function	863	Coro will check for the exception each time a schedule-like-function
528	returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down	864	returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down
529	>>, C<< Coro::Handle->readable >> and so on. Most of these functions	865	>>, C<< Coro::Handle->readable >> and so on. Most of those functions (all
530	detect this case and return early in case an exception is pending.	866	that are part of Coro itself) detect this case and return early in case an
		867	exception is pending.
531		868
532	The exception object will be thrown "as is" with the specified scalar in	869	The exception object will be thrown "as is" with the specified scalar in
533	C<$@>, i.e. if it is a string, no line number or newline will be appended	870	C<$@>, i.e. if it is a string, no line number or newline will be appended
534	(unlike with C<die>).	871	(unlike with C<die>).
535		872
536	This can be used as a softer means than C<cancel> to ask a coro to	873	This can be used as a softer means than either C<cancel> or C<safe_cancel
537	end itself, although there is no guarantee that the exception will lead to	874	>to ask a coro to end itself, although there is no guarantee that the
538	termination, and if the exception isn't caught it might well end the whole	875	exception will lead to termination, and if the exception isn't caught it
539	program.	876	might well end the whole program.
540		877
541	You might also think of C<throw> as being the moral equivalent of	878	You might also think of C<throw> as being the moral equivalent of
542	C<kill>ing a coro with a signal (in this case, a scalar).	879	C<kill>ing a coro with a signal (in this case, a scalar).
543		880
544	=item $coro->join	881	=item $coro->join
545		882
546	Wait until the coro terminates and return any values given to the	883	Wait until the coro terminates and return any values given to the
547	C<terminate> or C<cancel> functions. C<join> can be called concurrently	884	C<terminate> or C<cancel> functions. C<join> can be called concurrently
548	from multiple coro, and all will be resumed and given the status	885	from multiple threads, and all will be resumed and given the status
549	return once the C<$coro> terminates.	886	return once the C<$coro> terminates.
550		887
551	=cut
552
553	sub join {
554	my $self = shift;
555
556	unless ($self->{_status}) {
557	my $current = $current;
558
559	push @{$self->{_on_destroy}}, sub {
560	$current->ready;
561	undef $current;
562	};
563
564	&schedule while $current;
565	}
566
567	wantarray ? @{$self->{_status}} : $self->{_status}[0];
568	}
569
570	=item $coro->on_destroy (\&cb)	888	=item $coro->on_destroy (\&cb)
571		889
572	Registers a callback that is called when this coro gets destroyed,	890	Registers a callback that is called when this coro thread gets destroyed,
573	but before it is joined. The callback gets passed the terminate arguments,	891	that is, after it's resources have been freed but before it is joined. The
		892	callback gets passed the terminate/cancel arguments, if any, and I<must
574	if any, and I<must not> die, under any circumstances.	893	not> die, under any circumstances.
575		894
576	=cut	895	There can be any number of C<on_destroy> callbacks per coro, and there is
577		896	no way currently to remove a callback once added.
578	sub on_destroy {
579	my ($self, $cb) = @_;
580
581	push @{ $self->{_on_destroy} }, $cb;
582	}
583		897
584	=item $oldprio = $coro->prio ($newprio)	898	=item $oldprio = $coro->prio ($newprio)
585		899
586	Sets (or gets, if the argument is missing) the priority of the	900	Sets (or gets, if the argument is missing) the priority of the
587	coro. Higher priority coro get run before lower priority	901	coro thread. Higher priority coro get run before lower priority
588	coro. Priorities are small signed integers (currently -4 .. +3),	902	coros. Priorities are small signed integers (currently -4 .. +3),
589	that you can refer to using PRIO_xxx constants (use the import tag :prio	903	that you can refer to using PRIO_xxx constants (use the import tag :prio
590	to get then):	904	to get then):
591		905
592	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN	906	PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN
593	3 > 1 > 0 > -1 > -3 > -4	907	3 > 1 > 0 > -1 > -3 > -4
594		908
595	# set priority to HIGH	909	# set priority to HIGH
596	current->prio (PRIO_HIGH);	910	current->prio (PRIO_HIGH);
597		911
598	The idle coro ($Coro::idle) always has a lower priority than any	912	The idle coro thread ($Coro::idle) always has a lower priority than any
599	existing coro.	913	existing coro.
600		914
601	Changing the priority of the current coro will take effect immediately,	915	Changing the priority of the current coro will take effect immediately,
602	but changing the priority of coro in the ready queue (but not	916	but changing the priority of a coro in the ready queue (but not running)
603	running) will only take effect after the next schedule (of that	917	will only take effect after the next schedule (of that coro). This is a
604	coro). This is a bug that will be fixed in some future version.	918	bug that will be fixed in some future version.
605		919
606	=item $newprio = $coro->nice ($change)	920	=item $newprio = $coro->nice ($change)
607		921
608	Similar to C<prio>, but subtract the given value from the priority (i.e.	922	Similar to C<prio>, but subtract the given value from the priority (i.e.
609	higher values mean lower priority, just as in unix).	923	higher values mean lower priority, just as in UNIX's nice command).
610		924
611	=item $olddesc = $coro->desc ($newdesc)	925	=item $olddesc = $coro->desc ($newdesc)
612		926
613	Sets (or gets in case the argument is missing) the description for this	927	Sets (or gets in case the argument is missing) the description for this
614	coro. This is just a free-form string you can associate with a	928	coro thread. This is just a free-form string you can associate with a
615	coro.	929	coro.
616		930
617	This method simply sets the C<< $coro->{desc} >> member to the given	931	This method simply sets the C<< $coro->{desc} >> member to the given
618	string. You can modify this member directly if you wish, and in fact, this	932	string. You can modify this member directly if you wish, and in fact, this
619	is often preferred to indicate major processing states that cna then be	933	is often preferred to indicate major processing states that cna then be
…		…
757		1071
758	=back	1072	=back
759		1073
760	=cut	1074	=cut
761		1075
		1076	for my $module (qw(Channel RWLock Semaphore SemaphoreSet Signal Specific)) {
		1077	my $old = defined &{"Coro::$module\::new"} && \&{"Coro::$module\::new"};
		1078
		1079	*{"Coro::$module\::new"} = sub {
		1080	require "Coro/$module.pm";
		1081
		1082	# some modules have their new predefined in State.xs, some don't
		1083	*{"Coro::$module\::new"} = $old
		1084	if $old;
		1085
		1086	goto &{"Coro::$module\::new"};
		1087	};
		1088	}
		1089
762	1;	1090	1;
763		1091
764	=head1 HOW TO WAIT FOR A CALLBACK	1092	=head1 HOW TO WAIT FOR A CALLBACK
765		1093
766	It is very common for a coro to wait for some callback to be	1094	It is very common for a coro to wait for some callback to be
…		…
844	module from the first thread (this requirement might be removed in the	1172	module from the first thread (this requirement might be removed in the
845	future to allow per-thread schedulers, but Coro::State does not yet allow	1173	future to allow per-thread schedulers, but Coro::State does not yet allow
846	this). I recommend disabling thread support and using processes, as having	1174	this). I recommend disabling thread support and using processes, as having
847	the windows process emulation enabled under unix roughly halves perl	1175	the windows process emulation enabled under unix roughly halves perl
848	performance, even when not used.	1176	performance, even when not used.
		1177
		1178	Attempts to use threads created in another emulated process will crash
		1179	("cleanly", with a null pointer exception).
849		1180
850	=item coro switching is not signal safe	1181	=item coro switching is not signal safe
851		1182
852	You must not switch to another coro from within a signal handler (only	1183	You must not switch to another coro from within a signal handler (only
853	relevant with %SIG - most event libraries provide safe signals), I<unless>	1184	relevant with %SIG - most event libraries provide safe signals), I<unless>

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Comparing Coro/Coro.pm (file contents): Revision 1.282 by root, Sun Dec 26 16:23:51 2010 UTC vs. Revision 1.297 by root, Thu May 12 23:55:39 2011 UTC

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Comparing Coro/Coro.pm (file contents):
Revision 1.282 by root, Sun Dec 26 16:23:51 2010 UTC vs.
Revision 1.297 by root, Thu May 12 23:55:39 2011 UTC