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…		…
1	NAME	1	NAME
2	Coro - coroutine process abstraction	2	Coro - coroutine process abstraction
3		3
4	SYNOPSIS	4	SYNOPSIS
5	use Coro;	5	use Coro;
6		6
7	async {	7	async {
8	# some asynchronous thread of execution	8	# some asynchronous thread of execution
9	print "2\n";	9	print "2\n";
10	cede; # yield back to main	10	cede; # yield back to main
11	print "4\n";	11	print "4\n";
12	};	12	};
13	print "1\n";	13	print "1\n";
14	cede; # yield to coroutine	14	cede; # yield to coroutine
15	print "3\n";	15	print "3\n";
16	cede; # and again	16	cede; # and again
17		17
18	# use locking	18	# use locking
		19	use Coro::Semaphore;
19	my $lock = new Coro::Semaphore;	20	my $lock = new Coro::Semaphore;
20	my $locked;	21	my $locked;
21		22
22	$lock->down;	23	$lock->down;
23	$locked = 1;	24	$locked = 1;
24	$lock->up;	25	$lock->up;
25		26
26	DESCRIPTION	27	DESCRIPTION
27	This module collection manages coroutines. Coroutines are similar to	28	This module collection manages coroutines. Coroutines are similar to
28	threads but don't run in parallel at the same time even on SMP machines.	29	threads but don't (in general) run in parallel at the same time even on
29	The specific flavor of coroutine used in this module also guarantees you	30	SMP machines. The specific flavor of coroutine used in this module also
30	that it will not switch between coroutines unless necessary, at	31	guarantees you that it will not switch between coroutines unless
31	easily-identified points in your program, so locking and parallel access	32	necessary, at easily-identified points in your program, so locking and
32	are rarely an issue, making coroutine programming much safer than	33	parallel access are rarely an issue, making coroutine programming much
33	threads programming.	34	safer and easier than threads programming.
34		35
35	(Perl, however, does not natively support real threads but instead does	36	Unlike a normal perl program, however, coroutines allow you to have
36	a very slow and memory-intensive emulation of processes using threads.	37	multiple running interpreters that share data, which is especially
37	This is a performance win on Windows machines, and a loss everywhere	38	useful to code pseudo-parallel processes and for event-based
38	else).	39	programming, such as multiple HTTP-GET requests running concurrently.
		40	See Coro::AnyEvent to learn more.
		41
		42	Coroutines are also useful because Perl has no support for threads (the
		43	so called "threads" that perl offers are nothing more than the (bad)
		44	process emulation coming from the Windows platform: On standard
		45	operating systems they serve no purpose whatsoever, except by making
		46	your programs slow and making them use a lot of memory. Best disable
		47	them when building perl, or aks your software vendor/distributor to do
		48	it for you).
39		49
40	In this module, coroutines are defined as "callchain + lexical variables	50	In this module, coroutines are defined as "callchain + lexical variables
41	+ @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own	51	+ @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own
42	callchain, its own set of lexicals and its own set of perls most	52	callchain, its own set of lexicals and its own set of perls most
43	important global variables (see Coro::State for more configuration).	53	important global variables (see Coro::State for more configuration).
44		54
45	$main	55	$Coro::main
46	This coroutine represents the main program.	56	This variable stores the coroutine object that represents the main
		57	program. While you cna "ready" it and do most other things you can
		58	do to coroutines, it is mainly useful to compare again
		59	$Coro::current, to see whether you are running in the main program
		60	or not.
47		61
48	$current (or as function: current)	62	$Coro::current
49	The current coroutine (the last coroutine switched to). The initial	63	The coroutine object representing the current coroutine (the last
		64	coroutine that the Coro scheduler switched to). The initial value is
50	value is $main (of course).	65	$Coro::main (of course).
51		66
52	This variable is strictly read-only. It is provided for	67	This variable is strictly read-only. You can take copies of the
53	performance reasons. If performance is not essential you are	68	value stored in it and use it as any other coroutine object, but you
54	encouraged to use the "Coro::current" function instead.	69	must not otherwise modify the variable itself.
55		70
56	$idle	71	$Coro::idle
57	A callback that is called whenever the scheduler finds no ready	72	This variable is mainly useful to integrate Coro into event loops.
58	coroutines to run. The default implementation prints "FATAL:	73	It is usually better to rely on Coro::AnyEvent or L"Coro::EV", as
59	deadlock detected" and exits, because the program has no other way	74	this is pretty low-level functionality.
60	to continue.	75
		76	This variable stores a callback that is called whenever the
		77	scheduler finds no ready coroutines to run. The default
		78	implementation prints "FATAL: deadlock detected" and exits, because
		79	the program has no other way to continue.
61		80
62	This hook is overwritten by modules such as "Coro::Timer" and	81	This hook is overwritten by modules such as "Coro::Timer" and
63	"Coro::Event" to wait on an external event that hopefully wake up a	82	"Coro::AnyEvent" to wait on an external event that hopefully wake up
64	coroutine so the scheduler can run it.	83	a coroutine so the scheduler can run it.
		84
		85	Note that the callback must not, under any circumstances, block
		86	the current coroutine. Normally, this is achieved by having an "idle
		87	coroutine" that calls the event loop and then blocks again, and then
		88	readying that coroutine in the idle handler.
		89
		90	See Coro::Event or Coro::AnyEvent for examples of using this
		91	technique.
65		92
66	Please note that if your callback recursively invokes perl (e.g. for	93	Please note that if your callback recursively invokes perl (e.g. for
67	event handlers), then it must be prepared to be called recursively	94	event handlers), then it must be prepared to be called recursively
68	itself.	95	itself.
69		96
70	STATIC METHODS	97	SIMPLE COROUTINE CREATION
71	Static methods are actually functions that operate on the current
72	coroutine only.
73
74	async { ... } [@args...]	98	async { ... } [@args...]
75	Create a new asynchronous coroutine and return it's coroutine object	99	Create a new coroutine and return it's coroutine object (usually
76	(usually unused). When the sub returns the new coroutine is	100	unused). The coroutine will be put into the ready queue, so it will
		101	start running automatically on the next scheduler run.
		102
		103	The first argument is a codeblock/closure that should be executed in
		104	the coroutine. When it returns argument returns the coroutine is
77	automatically terminated.	105	automatically terminated.
78		106
		107	The remaining arguments are passed as arguments to the closure.
		108
79	See the "Coro::State::new" constructor for info about the coroutine	109	See the "Coro::State::new" constructor for info about the coroutine
80	environment in which coroutines run.	110	environment in which coroutines are executed.
81		111
82	Calling "exit" in a coroutine will do the same as calling exit	112	Calling "exit" in a coroutine will do the same as calling exit
83	outside the coroutine. Likewise, when the coroutine dies, the	113	outside the coroutine. Likewise, when the coroutine dies, the
84	program will exit, just as it would in the main program.	114	program will exit, just as it would in the main program.
85		115
		116	If you do not want that, you can provide a default "die" handler, or
		117	simply avoid dieing (by use of "eval").
		118
86	# create a new coroutine that just prints its arguments	119	Example: Create a new coroutine that just prints its arguments.
		120
87	async {	121	async {
88	print "@_\n";	122	print "@_\n";
89	} 1,2,3,4;	123	} 1,2,3,4;
90		124
91	async_pool { ... } [@args...]	125	async_pool { ... } [@args...]
92	Similar to "async", but uses a coroutine pool, so you should not	126	Similar to "async", but uses a coroutine pool, so you should not
93	call terminate or join (although you are allowed to), and you get a	127	call terminate or join on it (although you are allowed to), and you
94	coroutine that might have executed other code already (which can be	128	get a coroutine that might have executed other code already (which
95	good or bad :).	129	can be good or bad :).
96		130
		131	On the plus side, this function is about twice as fast as creating
		132	(and destroying) a completely new coroutine, so if you need a lot of
		133	generic coroutines in quick successsion, use "async_pool", not
		134	"async".
		135
97	Also, the block is executed in an "eval" context and a warning will	136	The code block is executed in an "eval" context and a warning will
98	be issued in case of an exception instead of terminating the	137	be issued in case of an exception instead of terminating the
99	program, as "async" does. As the coroutine is being reused, stuff	138	program, as "async" does. As the coroutine is being reused, stuff
100	like "on_destroy" will not work in the expected way, unless you call	139	like "on_destroy" will not work in the expected way, unless you call
101	terminate or cancel, which somehow defeats the purpose of pooling.	140	terminate or cancel, which somehow defeats the purpose of pooling
		141	(but is fine in the exceptional case).
102		142
103	The priority will be reset to 0 after each job, tracing will be	143	The priority will be reset to 0 after each run, tracing will be
104	disabled, the description will be reset and the default output	144	disabled, the description will be reset and the default output
105	filehandle gets restored, so you can change alkl these. Otherwise	145	filehandle gets restored, so you can change all these. Otherwise the
106	the coroutine will be re-used "as-is": most notably if you change	146	coroutine will be re-used "as-is": most notably if you change other
107	other per-coroutine global stuff such as $/ you need to revert that	147	per-coroutine global stuff such as $/ you must needs revert that
108	change, which is most simply done by using local as in " local $/ ".	148	change, which is most simply done by using local as in: "local $/".
109		149
110	The pool size is limited to 8 idle coroutines (this can be adjusted	150	The idle pool size is limited to 8 idle coroutines (this can be
111	by changing $Coro::POOL_SIZE), and there can be as many non-idle	151	adjusted by changing $Coro::POOL_SIZE), but there can be as many
112	coros as required.	152	non-idle coros as required.
113		153
114	If you are concerned about pooled coroutines growing a lot because a	154	If you are concerned about pooled coroutines growing a lot because a
115	single "async_pool" used a lot of stackspace you can e.g.	155	single "async_pool" used a lot of stackspace you can e.g.
116	"async_pool { terminate }" once per second or so to slowly replenish	156	"async_pool { terminate }" once per second or so to slowly replenish
117	the pool. In addition to that, when the stacks used by a handler	157	the pool. In addition to that, when the stacks used by a handler
118	grows larger than 16kb (adjustable with $Coro::POOL_RSS) it will	158	grows larger than 16kb (adjustable via $Coro::POOL_RSS) it will also
119	also exit.	159	be destroyed.
		160
		161	STATIC METHODS
		162	Static methods are actually functions that operate on the current
		163	coroutine.
120		164
121	schedule	165	schedule
122	Calls the scheduler. Please note that the current coroutine will not	166	Calls the scheduler. The scheduler will find the next coroutine that
		167	is to be run from the ready queue and switches to it. The next
		168	coroutine to be run is simply the one with the highest priority that
		169	is longest in its ready queue. If there is no coroutine ready, it
		170	will clal the $Coro::idle hook.
		171
		172	Please note that the current coroutine will not be put into the
123	be put into the ready queue, so calling this function usually means	173	ready queue, so calling this function usually means you will never
124	you will never be called again unless something else (e.g. an event	174	be called again unless something else (e.g. an event handler) calls
125	handler) calls ready.	175	"->ready", thus waking you up.
126		176
127	The canonical way to wait on external events is this:	177	This makes "schedule" the generic method to use to block the
		178	current coroutine and wait for events: first you remember the
		179	current coroutine in a variable, then arrange for some callback of
		180	yours to call "->ready" on that once some event happens, and last
		181	you call "schedule" to put yourself to sleep. Note that a lot of
		182	things can wake your coroutine up, so you need to check whether the
		183	event indeed happened, e.g. by storing the status in a variable.
128		184
129	{	185	See HOW TO WAIT FOR A CALLBACK, below, for some ways to wait for
130	# remember current coroutine	186	callbacks.
131	my $current = $Coro::current;
132
133	# register a hypothetical event handler
134	on_event_invoke sub {
135	# wake up sleeping coroutine
136	$current->ready;
137	undef $current;
138	};
139
140	# call schedule until event occurred.
141	# in case we are woken up for other reasons
142	# (current still defined), loop.
143	Coro::schedule while $current;
144	}
145		187
146	cede	188	cede
147	"Cede" to other coroutines. This function puts the current coroutine	189	"Cede" to other coroutines. This function puts the current coroutine
148	into the ready queue and calls "schedule", which has the effect of	190	into the ready queue and calls "schedule", which has the effect of
149	giving up the current "timeslice" to other coroutines of the same or	191	giving up the current "timeslice" to other coroutines of the same or
150	higher priority.	192	higher priority. Once your coroutine gets its turn again it will
		193	automatically be resumed.
		194
		195	This function is often called "yield" in other languages.
151		196
152	Coro::cede_notself	197	Coro::cede_notself
153	Works like cede, but is not exported by default and will cede to any	198	Works like cede, but is not exported by default and will cede to
154	coroutine, regardless of priority, once.	199	any coroutine, regardless of priority. This is useful sometimes to
		200	ensure progress is made.
155		201
156	terminate [arg...]	202	terminate [arg...]
157	Terminates the current coroutine with the given status values (see	203	Terminates the current coroutine with the given status values (see
158	cancel).	204	cancel).
159		205
160	killall	206	killall
161	Kills/terminates/cancels all coroutines except the currently running	207	Kills/terminates/cancels all coroutines except the currently running
162	one. This is useful after a fork, either in the child or the parent,	208	one. This is useful after a fork, either in the child or the parent,
163	as usually only one of them should inherit the running coroutines.	209	as usually only one of them should inherit the running coroutines.
164		210
165	# dynamic methods	211	Note that while this will try to free some of the main programs
		212	resources, you cannot free all of them, so if a coroutine that is
		213	not the main program calls this function, there will be some
		214	one-time resource leak.
166		215
167	COROUTINE METHODS	216	COROUTINE METHODS
168	These are the methods you can call on coroutine objects.	217	These are the methods you can call on coroutine objects (or to create
		218	them).
169		219
170	new Coro \&sub [, @args...]	220	new Coro \&sub [, @args...]
171	Create a new coroutine and return it. When the sub returns the	221	Create a new coroutine and return it. When the sub returns, the
172	coroutine automatically terminates as if "terminate" with the	222	coroutine automatically terminates as if "terminate" with the
173	returned values were called. To make the coroutine run you must	223	returned values were called. To make the coroutine run you must
174	first put it into the ready queue by calling the ready method.	224	first put it into the ready queue by calling the ready method.
175		225
176	See "async" and "Coro::State::new" for additional info about the	226	See "async" and "Coro::State::new" for additional info about the
177	coroutine environment.	227	coroutine environment.
178		228
179	$success = $coroutine->ready	229	$success = $coroutine->ready
180	Put the given coroutine into the ready queue (according to it's	230	Put the given coroutine into the end of its ready queue (there is
181	priority) and return true. If the coroutine is already in the ready	231	one queue for each priority) and return true. If the coroutine is
182	queue, do nothing and return false.	232	already in the ready queue, do nothing and return false.
		233
		234	This ensures that the scheduler will resume this coroutine
		235	automatically once all the coroutines of higher priority and all
		236	coroutines of the same priority that were put into the ready queue
		237	earlier have been resumed.
183		238
184	$is_ready = $coroutine->is_ready	239	$is_ready = $coroutine->is_ready
185	Return wether the coroutine is currently the ready queue or not,	240	Return whether the coroutine is currently the ready queue or not,
186		241
187	$coroutine->cancel (arg...)	242	$coroutine->cancel (arg...)
188	Terminates the given coroutine and makes it return the given	243	Terminates the given coroutine and makes it return the given
189	arguments as status (default: the empty list). Never returns if the	244	arguments as status (default: the empty list). Never returns if the
190	coroutine is the current coroutine.	245	coroutine is the current coroutine.
191		246
		247	$coroutine->schedule_to
		248	Puts the current coroutine to sleep (like "Coro::schedule"), but
		249	instead of continuing with the next coro from the ready queue,
		250	always switch to the given coroutine object (regardless of priority
		251	etc.). The readyness state of that coroutine isn't changed.
		252
		253	This is an advanced method for special cases - I'd love to hear
		254	about any uses for this one.
		255
		256	$coroutine->cede_to
		257	Like "schedule_to", but puts the current coroutine into the ready
		258	queue. This has the effect of temporarily switching to the given
		259	coroutine, and continuing some time later.
		260
		261	This is an advanced method for special cases - I'd love to hear
		262	about any uses for this one.
		263
		264	$coroutine->throw ([$scalar])
		265	If $throw is specified and defined, it will be thrown as an
		266	exception inside the coroutine at the next convenient point in time.
		267	Otherwise clears the exception object.
		268
		269	Coro will check for the exception each time a schedule-like-function
		270	returns, i.e. after each "schedule", "cede",
		271	"Coro::Semaphore->down", "Coro::Handle->readable" and so on. Most of
		272	these functions detect this case and return early in case an
		273	exception is pending.
		274
		275	The exception object will be thrown "as is" with the specified
		276	scalar in $@, i.e. if it is a string, no line number or newline will
		277	be appended (unlike with "die").
		278
		279	This can be used as a softer means than "cancel" to ask a coroutine
		280	to end itself, although there is no guarantee that the exception
		281	will lead to termination, and if the exception isn't caught it might
		282	well end the whole program.
		283
		284	You might also think of "throw" as being the moral equivalent of
		285	"kill"ing a coroutine with a signal (in this case, a scalar).
		286
192	$coroutine->join	287	$coroutine->join
193	Wait until the coroutine terminates and return any values given to	288	Wait until the coroutine terminates and return any values given to
194	the "terminate" or "cancel" functions. "join" can be called	289	the "terminate" or "cancel" functions. "join" can be called
195	concurrently from multiple coroutines.	290	concurrently from multiple coroutines, and all will be resumed and
		291	given the status return once the $coroutine terminates.
196		292
197	$coroutine->on_destroy (\&cb)	293	$coroutine->on_destroy (\&cb)
198	Registers a callback that is called when this coroutine gets	294	Registers a callback that is called when this coroutine gets
199	destroyed, but before it is joined. The callback gets passed the	295	destroyed, but before it is joined. The callback gets passed the
200	terminate arguments, if any.	296	terminate arguments, if any, and must not die, under any
		297	circumstances.
201		298
202	$oldprio = $coroutine->prio ($newprio)	299	$oldprio = $coroutine->prio ($newprio)
203	Sets (or gets, if the argument is missing) the priority of the	300	Sets (or gets, if the argument is missing) the priority of the
204	coroutine. Higher priority coroutines get run before lower priority	301	coroutine. Higher priority coroutines get run before lower priority
205	coroutines. Priorities are small signed integers (currently -4 ..	302	coroutines. Priorities are small signed integers (currently -4 ..
231	with a coroutine.	328	with a coroutine.
232		329
233	This method simply sets the "$coroutine->{desc}" member to the given	330	This method simply sets the "$coroutine->{desc}" member to the given
234	string. You can modify this member directly if you wish.	331	string. You can modify this member directly if you wish.
235		332
236	$coroutine->throw ([$scalar])
237	If $throw is specified and defined, it will be thrown as an
238	exception inside the coroutine at the next convinient point in time
239	(usually after it gains control at the next schedule/transfer/cede).
240	Otherwise clears the exception object.
241
242	The exception object will be thrown "as is" with the specified
243	scalar in $@, i.e. if it is a string, no line number or newline will
244	be appended (unlike with "die").
245
246	This can be used as a softer means than "cancel" to ask a coroutine
247	to end itself, although there is no guarentee that the exception
248	will lead to termination, and if the exception isn't caught it might
249	well end the whole program.
250
251	GLOBAL FUNCTIONS	333	GLOBAL FUNCTIONS
252	Coro::nready	334	Coro::nready
253	Returns the number of coroutines that are currently in the ready	335	Returns the number of coroutines that are currently in the ready
254	state, i.e. that can be switched to. The value 0 means that the only	336	state, i.e. that can be switched to by calling "schedule" directory
255	runnable coroutine is the currently running one, so "cede" would	337	or indirectly. The value 0 means that the only runnable coroutine is
256	have no effect, and "schedule" would cause a deadlock unless there	338	the currently running one, so "cede" would have no effect, and
		339	"schedule" would cause a deadlock unless there is an idle handler
257	is an idle handler that wakes up some coroutines.	340	that wakes up some coroutines.
258		341
259	my $guard = Coro::guard { ... }	342	my $guard = Coro::guard { ... }
260	This creates and returns a guard object. Nothing happens until the	343	This creates and returns a guard object. Nothing happens until the
261	object gets destroyed, in which case the codeblock given as argument	344	object gets destroyed, in which case the codeblock given as argument
262	will be executed. This is useful to free locks or other resources in	345	will be executed. This is useful to free locks or other resources in
…		…
275	# do something that requires $busy to be true	358	# do something that requires $busy to be true
276	}	359	}
277		360
278	unblock_sub { ... }	361	unblock_sub { ... }
279	This utility function takes a BLOCK or code reference and "unblocks"	362	This utility function takes a BLOCK or code reference and "unblocks"
280	it, returning the new coderef. This means that the new coderef will	363	it, returning a new coderef. Unblocking means that calling the new
281	return immediately without blocking, returning nothing, while the	364	coderef will return immediately without blocking, returning nothing,
282	original code ref will be called (with parameters) from within its	365	while the original code ref will be called (with parameters) from
283	own coroutine.	366	within another coroutine.
284		367
285	The reason this function exists is that many event libraries (such	368	The reason this function exists is that many event libraries (such
286	as the venerable Event module) are not coroutine-safe (a weaker form	369	as the venerable Event module) are not coroutine-safe (a weaker form
287	of thread-safety). This means you must not block within event	370	of thread-safety). This means you must not block within event
288	callbacks, otherwise you might suffer from crashes or worse.	371	callbacks, otherwise you might suffer from crashes or worse. The
		372	only event library currently known that is safe to use without
		373	"unblock_sub" is EV.
289		374
290	This function allows your callbacks to block by executing them in	375	This function allows your callbacks to block by executing them in
291	another coroutine where it is safe to block. One example where	376	another coroutine where it is safe to block. One example where
292	blocking is handy is when you use the Coro::AIO functions to save	377	blocking is handy is when you use the Coro::AIO functions to save
293	results to disk.	378	results to disk, for example.
294		379
295	In short: simply use "unblock_sub { ... }" instead of "sub { ... }"	380	In short: simply use "unblock_sub { ... }" instead of "sub { ... }"
296	when creating event callbacks that want to block.	381	when creating event callbacks that want to block.
297		382
		383	If your handler does not plan to block (e.g. simply sends a message
		384	to another coroutine, or puts some other coroutine into the ready
		385	queue), there is no reason to use "unblock_sub".
		386
		387	Note that you also need to use "unblock_sub" for any other callbacks
		388	that are indirectly executed by any C-based event loop. For example,
		389	when you use a module that uses AnyEvent (and you use
		390	Coro::AnyEvent) and it provides callbacks that are the result of
		391	some event callback, then you must not block either, or use
		392	"unblock_sub".
		393
		394	$cb = Coro::rouse_cb
		395	Create and return a "rouse callback". That's a code reference that,
		396	when called, will save its arguments and notify the owner coroutine
		397	of the callback.
		398
		399	See the next function.
		400
		401	@args = Coro::rouse_wait [$cb]
		402	Wait for the specified rouse callback (or the last one tht was
		403	created in this coroutine).
		404
		405	As soon as the callback is invoked (or when the calback was invoked
		406	before "rouse_wait"), it will return a copy of the arguments
		407	originally passed to the rouse callback.
		408
		409	See the section HOW TO WAIT FOR A CALLBACK for an actual usage
		410	example.
		411
		412	HOW TO WAIT FOR A CALLBACK
		413	It is very common for a coroutine to wait for some callback to be
		414	called. This occurs naturally when you use coroutines in an otherwise
		415	event-based program, or when you use event-based libraries.
		416
		417	These typically register a callback for some event, and call that
		418	callback when the event occured. In a coroutine, however, you typically
		419	want to just wait for the event, simplyifying things.
		420
		421	For example "AnyEvent->child" registers a callback to be called when a
		422	specific child has exited:
		423
		424	my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... });
		425
		426	But from withina coroutine, you often just want to write this:
		427
		428	my $status = wait_for_child $pid;
		429
		430	Coro offers two functions specifically designed to make this easy,
		431	"Coro::rouse_cb" and "Coro::rouse_wait".
		432
		433	The first function, "rouse_cb", generates and returns a callback that,
		434	when invoked, will save it's arguments and notify the coroutine that
		435	created the callback.
		436
		437	The second function, "rouse_wait", waits for the callback to be called
		438	(by calling "schedule" to go to sleep) and returns the arguments
		439	originally passed to the callback.
		440
		441	Using these functions, it becomes easy to write the "wait_for_child"
		442	function mentioned above:
		443
		444	sub wait_for_child($) {
		445	my ($pid) = @_;
		446
		447	my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb);
		448
		449	my ($rpid, $rstatus) = Coro::rouse_wait;
		450	$rstatus
		451	}
		452
		453	In the case where "rouse_cb" and "rouse_wait" are not flexible enough,
		454	you can roll your own, using "schedule":
		455
		456	sub wait_for_child($) {
		457	my ($pid) = @_;
		458
		459	# store the current coroutine in $current,
		460	# and provide result variables for the closure passed to ->child
		461	my $current = $Coro::current;
		462	my ($done, $rstatus);
		463
		464	# pass a closure to ->child
		465	my $watcher = AnyEvent->child (pid => $pid, cb => sub {
		466	$rstatus = $_[1]; # remember rstatus
		467	$done = 1; # mark $rstatus as valud
		468	});
		469
		470	# wait until the closure has been called
		471	schedule while !$done;
		472
		473	$rstatus
		474	}
		475
298	BUGS/LIMITATIONS	476	BUGS/LIMITATIONS
299	- you must make very sure that no coro is still active on global	477	fork with pthread backend
300	destruction. very bad things might happen otherwise (usually segfaults).	478	When Coro is compiled using the pthread backend (which isn't
		479	recommended but required on many BSDs as their libcs are completely
		480	broken), then coroutines will not survive a fork. There is no known
		481	workaround except to fix your libc and use a saner backend.
301		482
		483	perl process emulation ("threads")
302	- this module is not thread-safe. You should only ever use this module	484	This module is not perl-pseudo-thread-safe. You should only ever use
303	from the same thread (this requirement might be loosened in the future	485	this module from the same thread (this requirement might be removed
304	to allow per-thread schedulers, but Coro::State does not yet allow	486	in the future to allow per-thread schedulers, but Coro::State does
305	this).	487	not yet allow this). I recommend disabling thread support and using
		488	processes, as having the windows process emulation enabled under
		489	unix roughly halves perl performance, even when not used.
		490
		491	coroutine switching not signal safe
		492	You must not switch to another coroutine from within a signal
		493	handler (only relevant with %SIG - most event libraries provide safe
		494	signals).
		495
		496	That means you MUST NOT call any function that might "block" the
		497	current coroutine - "cede", "schedule" "Coro::Semaphore->down" or
		498	anything that calls those. Everything else, including calling
		499	"ready", works.
306		500
307	SEE ALSO	501	SEE ALSO
308	Lower level Configuration, Coroutine Environment: Coro::State.	502	Event-Loop integration: Coro::AnyEvent, Coro::EV, Coro::Event.
309		503
310	Debugging: Coro::Debug.	504	Debugging: Coro::Debug.
311		505
312	Support/Utility: Coro::Specific, Coro::Util.	506	Support/Utility: Coro::Specific, Coro::Util.
313		507
314	Locking/IPC: Coro::Signal, Coro::Channel, Coro::Semaphore,	508	Locking/IPC: Coro::Signal, Coro::Channel, Coro::Semaphore,
315	Coro::SemaphoreSet, Coro::RWLock.	509	Coro::SemaphoreSet, Coro::RWLock.
316		510
317	Event/IO: Coro::Timer, Coro::Event, Coro::Handle, Coro::Socket.	511	IO/Timers: Coro::Timer, Coro::Handle, Coro::Socket, Coro::AIO.
318		512
319	Compatibility: Coro::LWP, Coro::Storable, Coro::Select.	513	Compatibility: Coro::LWP, Coro::BDB, Coro::Storable, Coro::Select.
320		514
321	Embedding: Coro::MakeMaker.	515	XS API: Coro::MakeMaker.
		516
		517	Low level Configuration, Coroutine Environment: Coro::State.
322		518
323	AUTHOR	519	AUTHOR
324	Marc Lehmann <schmorp@schmorp.de>	520	Marc Lehmann <schmorp@schmorp.de>
325	http://home.schmorp.de/	521	http://home.schmorp.de/
326		522

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Revision 1.18 by root, Thu Nov 20 09:37:21 2008 UTC