[ViewVC] Diff of: cvs/AnyEvent-Fork/Fork.pm

Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.23 by root, Sat Apr 6 08:29:43 2013 UTC vs.
Revision 1.63 by root, Wed Nov 26 13:36:18 2014 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::Fork;	7	use AnyEvent::Fork;
8		8
9	##################################################################	9	AnyEvent::Fork
		10	->new
		11	->require ("MyModule")
		12	->run ("MyModule::server", my $cv = AE::cv);
		13
		14	my $fh = $cv->recv;
		15
		16	=head1 DESCRIPTION
		17
		18	This module allows you to create new processes, without actually forking
		19	them from your current process (avoiding the problems of forking), but
		20	preserving most of the advantages of fork.
		21
		22	It can be used to create new worker processes or new independent
		23	subprocesses for short- and long-running jobs, process pools (e.g. for use
		24	in pre-forked servers) but also to spawn new external processes (such as
		25	CGI scripts from a web server), which can be faster (and more well behaved)
		26	than using fork+exec in big processes.
		27
		28	Special care has been taken to make this module useful from other modules,
		29	while still supporting specialised environments such as L<App::Staticperl>
		30	or L<PAR::Packer>.
		31
		32	=head2 WHAT THIS MODULE IS NOT
		33
		34	This module only creates processes and lets you pass file handles and
		35	strings to it, and run perl code. It does not implement any kind of RPC -
		36	there is no back channel from the process back to you, and there is no RPC
		37	or message passing going on.
		38
		39	If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC>
		40	companion module, which adds simple RPC/job queueing to a process created
		41	by this module.
		42
		43	And if you need some automatic process pool management on top of
		44	L<AnyEvent::Fork::RPC>, you can look at the L<AnyEvent::Fork::Pool>
		45	companion module.
		46
		47	Or you can implement it yourself in whatever way you like: use some
		48	message-passing module such as L<AnyEvent::MP>, some pipe such as
		49	L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send
		50	e.g. JSON or Storable messages, and so on.
		51
		52	=head2 COMPARISON TO OTHER MODULES
		53
		54	There is an abundance of modules on CPAN that do "something fork", such as
		55	L<Parallel::ForkManager>, L<AnyEvent::ForkManager>, L<AnyEvent::Worker>
		56	or L<AnyEvent::Subprocess>. There are modules that implement their own
		57	process management, such as L<AnyEvent::DBI>.
		58
		59	The problems that all these modules try to solve are real, however, none
		60	of them (from what I have seen) tackle the very real problems of unwanted
		61	memory sharing, efficiency or not being able to use event processing, GUI
		62	toolkits or similar modules in the processes they create.
		63
		64	This module doesn't try to replace any of them - instead it tries to solve
		65	the problem of creating processes with a minimum of fuss and overhead (and
		66	also luxury). Ideally, most of these would use AnyEvent::Fork internally,
		67	except they were written before AnyEvent:Fork was available, so obviously
		68	had to roll their own.
		69
		70	=head2 PROBLEM STATEMENT
		71
		72	There are two traditional ways to implement parallel processing on UNIX
		73	like operating systems - fork and process, and fork+exec and process. They
		74	have different advantages and disadvantages that I describe below,
		75	together with how this module tries to mitigate the disadvantages.
		76
		77	=over 4
		78
		79	=item Forking from a big process can be very slow.
		80
		81	A 5GB process needs 0.05s to fork on my 3.6GHz amd64 GNU/Linux box. This
		82	overhead is often shared with exec (because you have to fork first), but
		83	in some circumstances (e.g. when vfork is used), fork+exec can be much
		84	faster.
		85
		86	This module can help here by telling a small(er) helper process to fork,
		87	which is faster then forking the main process, and also uses vfork where
		88	possible. This gives the speed of vfork, with the flexibility of fork.
		89
		90	=item Forking usually creates a copy-on-write copy of the parent
		91	process.
		92
		93	For example, modules or data files that are loaded will not use additional
		94	memory after a fork. Exec'ing a new process, in contrast, means modules
		95	and data files might need to be loaded again, at extra CPU and memory
		96	cost.
		97
		98	But when forking, you still create a copy of your data structures - if
		99	the program frees them and replaces them by new data, the child processes
		100	will retain the old version even if it isn't used, which can suddenly and
		101	unexpectedly increase memory usage when freeing memory.
		102
		103	For example, L<Gtk2::CV> is an image viewer optimised for large
		104	directories (millions of pictures). It also forks subprocesses for
		105	thumbnail generation, which inherit the data structure that stores all
		106	file information. If the user changes the directory, it gets freed in
		107	the main process, leaving a copy in the thumbnailer processes. This can
		108	lead to many times the memory usage that would actually be required. The
		109	solution is to fork early (and being unable to dynamically generate more
		110	subprocesses or do this from a module)... or to use L<AnyEvent:Fork>.
		111
		112	There is a trade-off between more sharing with fork (which can be good or
		113	bad), and no sharing with exec.
		114
		115	This module allows the main program to do a controlled fork, and allows
		116	modules to exec processes safely at any time. When creating a custom
		117	process pool you can take advantage of data sharing via fork without
		118	risking to share large dynamic data structures that will blow up child
		119	memory usage.
		120
		121	In other words, this module puts you into control over what is being
		122	shared and what isn't, at all times.
		123
		124	=item Exec'ing a new perl process might be difficult.
		125
		126	For example, it is not easy to find the correct path to the perl
		127	interpreter - C<$^X> might not be a perl interpreter at all. Worse, there
		128	might not even be a perl binary installed on the system.
		129
		130	This module tries hard to identify the correct path to the perl
		131	interpreter. With a cooperative main program, exec'ing the interpreter
		132	might not even be necessary, but even without help from the main program,
		133	it will still work when used from a module.
		134
		135	=item Exec'ing a new perl process might be slow, as all necessary modules
		136	have to be loaded from disk again, with no guarantees of success.
		137
		138	Long running processes might run into problems when perl is upgraded
		139	and modules are no longer loadable because they refer to a different
		140	perl version, or parts of a distribution are newer than the ones already
		141	loaded.
		142
		143	This module supports creating pre-initialised perl processes to be used as
		144	a template for new processes at a later time, e.g. for use in a process
		145	pool.
		146
		147	=item Forking might be impossible when a program is running.
		148
		149	For example, POSIX makes it almost impossible to fork from a
		150	multi-threaded program while doing anything useful in the child - in
		151	fact, if your perl program uses POSIX threads (even indirectly via
		152	e.g. L<IO::AIO> or L<threads>), you cannot call fork on the perl level
		153	anymore without risking memory corruption or worse on a number of
		154	operating systems.
		155
		156	This module can safely fork helper processes at any time, by calling
		157	fork+exec in C, in a POSIX-compatible way (via L<Proc::FastSpawn>).
		158
		159	=item Parallel processing with fork might be inconvenient or difficult
		160	to implement. Modules might not work in both parent and child.
		161
		162	For example, when a program uses an event loop and creates watchers it
		163	becomes very hard to use the event loop from a child program, as the
		164	watchers already exist but are only meaningful in the parent. Worse, a
		165	module might want to use such a module, not knowing whether another module
		166	or the main program also does, leading to problems.
		167
		168	Apart from event loops, graphical toolkits also commonly fall into the
		169	"unsafe module" category, or just about anything that communicates with
		170	the external world, such as network libraries and file I/O modules, which
		171	usually don't like being copied and then allowed to continue in two
		172	processes.
		173
		174	With this module only the main program is allowed to create new processes
		175	by forking (because only the main program can know when it is still safe
		176	to do so) - all other processes are created via fork+exec, which makes it
		177	possible to use modules such as event loops or window interfaces safely.
		178
		179	=back
		180
		181	=head1 EXAMPLES
		182
10	# create a single new process, tell it to run your worker function	183	=head2 Create a single new process, tell it to run your worker function.
11		184
12	AnyEvent::Fork	185	AnyEvent::Fork
13	->new	186	->new
14	->require ("MyModule")	187	->require ("MyModule")
15	->run ("MyModule::worker, sub {	188	->run ("MyModule::worker, sub {
…		…
17		190
18	# now $master_filehandle is connected to the	191	# now $master_filehandle is connected to the
19	# $slave_filehandle in the new process.	192	# $slave_filehandle in the new process.
20	});	193	});
21		194
22	# MyModule::worker might look like this	195	C<MyModule> might look like this:
		196
		197	package MyModule;
		198
23	sub MyModule::worker {	199	sub worker {
24	my ($slave_filehandle) = @_;	200	my ($slave_filehandle) = @_;
25		201
26	# now $slave_filehandle is connected to the $master_filehandle	202	# now $slave_filehandle is connected to the $master_filehandle
27	# in the original prorcess. have fun!	203	# in the original prorcess. have fun!
28	}	204	}
29		205
30	##################################################################
31	# create a pool of server processes all accepting on the same socket	206	=head2 Create a pool of server processes all accepting on the same socket.
32		207
33	# create listener socket	208	# create listener socket
34	my $listener = ...;	209	my $listener = ...;
35		210
36	# create a pool template, initialise it and give it the socket	211	# create a pool template, initialise it and give it the socket
…		…
48	}	223	}
49		224
50	# now do other things - maybe use the filehandle provided by run	225	# now do other things - maybe use the filehandle provided by run
51	# to wait for the processes to die. or whatever.	226	# to wait for the processes to die. or whatever.
52		227
53	# My::Server::run might look like this	228	C<My::Server> might look like this:
54	sub My::Server::run {	229
		230	package My::Server;
		231
		232	sub run {
55	my ($slave, $listener, $id) = @_;	233	my ($slave, $listener, $id) = @_;
56		234
57	close $slave; # we do not use the socket, so close it to save resources	235	close $slave; # we do not use the socket, so close it to save resources
58		236
59	# we could go ballistic and use e.g. AnyEvent here, or IO::AIO,	237	# we could go ballistic and use e.g. AnyEvent here, or IO::AIO,
…		…
61	while (my $socket = $listener->accept) {	239	while (my $socket = $listener->accept) {
62	# do sth. with new socket	240	# do sth. with new socket
63	}	241	}
64	}	242	}
65		243
66	##################################################################
67	# use AnyEvent::Fork as a faster fork+exec	244	=head2 use AnyEvent::Fork as a faster fork+exec
68		245
69	# this runs /bin/echo hi, with stdout redirected to /tmp/log	246	This runs C</bin/echo hi>, with standard output redirected to F</tmp/log>
70	# and stderr to the communications socket. it is usually faster	247	and standard error redirected to the communications socket. It is usually
71	# than fork+exec, but still let's you prepare the environment.	248	faster than fork+exec, but still lets you prepare the environment.
72		249
73	open my $output, ">/tmp/log" or die "$!";	250	open my $output, ">/tmp/log" or die "$!";
74		251
75	AnyEvent::Fork	252	AnyEvent::Fork
76	->new	253	->new
77	->eval ('	254	->eval ('
		255	# compile a helper function for later use
78	sub run {	256	sub run {
79	my ($fh, $output, @cmd) = @_;	257	my ($fh, $output, @cmd) = @_;
80		258
81	# perl will clear close-on-exec on STDOUT/STDERR	259	# perl will clear close-on-exec on STDOUT/STDERR
82	open STDOUT, ">&", $output or die;	260	open STDOUT, ">&", $output or die;
…		…
89	->send_arg ("/bin/echo", "hi")	267	->send_arg ("/bin/echo", "hi")
90	->run ("run", my $cv = AE::cv);	268	->run ("run", my $cv = AE::cv);
91		269
92	my $stderr = $cv->recv;	270	my $stderr = $cv->recv;
93		271
94	=head1 DESCRIPTION	272	=head2 For stingy users: put the worker code into a C<DATA> section.
95		273
96	This module allows you to create new processes, without actually forking	274	When you want to be stingy with files, you can put your code into the
97	them from your current process (avoiding the problems of forking), but	275	C<DATA> section of your module (or program):
98	preserving most of the advantages of fork.
99		276
100	It can be used to create new worker processes or new independent	277	use AnyEvent::Fork;
101	subprocesses for short- and long-running jobs, process pools (e.g. for use
102	in pre-forked servers) but also to spawn new external processes (such as
103	CGI scripts from a web server), which can be faster (and more well behaved)
104	than using fork+exec in big processes.
105		278
106	Special care has been taken to make this module useful from other modules,	279	AnyEvent::Fork
107	while still supporting specialised environments such as L<App::Staticperl>	280	->new
108	or L<PAR::Packer>.	281	->eval (do { local $/; <DATA> })
		282	->run ("doit", sub { ... });
109		283
110	=head1 WHAT THIS MODULE IS NOT	284	__DATA__
111		285
112	This module only creates processes and lets you pass file handles and	286	sub doit {
113	strings to it, and run perl code. It does not implement any kind of RPC -	287	... do something!
114	there is no back channel from the process back to you, and there is no RPC	288	}
115	or message passing going on.
116		289
117	If you need some form of RPC, you can either implement it yourself	290	=head2 For stingy standalone programs: do not rely on external files at
118	in whatever way you like, use some message-passing module such	291	all.
119	as L<AnyEvent::MP>, some pipe such as L<AnyEvent::ZeroMQ>, use
120	L<AnyEvent::Handle> on both sides to send e.g. JSON or Storable messages,
121	and so on.
122		292
123	=head1 PROBLEM STATEMENT	293	For single-file scripts it can be inconvenient to rely on external
		294	files - even when using a C<DATA> section, you still need to C<exec> an
		295	external perl interpreter, which might not be available when using
		296	L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example.
124		297
125	There are two ways to implement parallel processing on UNIX like operating	298	Two modules help here - L<AnyEvent::Fork::Early> forks a template process
126	systems - fork and process, and fork+exec and process. They have different	299	for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template>
127	advantages and disadvantages that I describe below, together with how this	300	forks the main program as a template process.
128	module tries to mitigate the disadvantages.
129		301
130	=over 4	302	Here is how your main program should look like:
131		303
132	=item Forking from a big process can be very slow (a 5GB process needs	304	#! perl
133	0.05s to fork on my 3.6GHz amd64 GNU/Linux box for example). This overhead
134	is often shared with exec (because you have to fork first), but in some
135	circumstances (e.g. when vfork is used), fork+exec can be much faster.
136		305
137	This module can help here by telling a small(er) helper process to fork,	306	# optional, as the very first thing.
138	or fork+exec instead.	307	# in case modules want to create their own processes.
		308	use AnyEvent::Fork::Early;
139		309
140	=item Forking usually creates a copy-on-write copy of the parent	310	# next, load all modules you need in your template process
141	process. Memory (for example, modules or data files that have been	311	use Example::My::Module
142	will not take additional memory). When exec'ing a new process, modules	312	use Example::Whatever;
143	and data files might need to be loaded again, at extra CPU and memory
144	cost. Likewise when forking, all data structures are copied as well - if
145	the program frees them and replaces them by new data, the child processes
146	will retain the memory even if it isn't used.
147		313
148	This module allows the main program to do a controlled fork, and allows	314	# next, put your run function definition and anything else you
149	modules to exec processes safely at any time. When creating a custom	315	# need, but do not use code outside of BEGIN blocks.
150	process pool you can take advantage of data sharing via fork without	316	sub worker_run {
151	risking to share large dynamic data structures that will blow up child	317	my ($fh, @args) = @_;
152	memory usage.	318	...
		319	}
153		320
154	=item Exec'ing a new perl process might be difficult and slow. For	321	# now preserve everything so far as AnyEvent::Fork object
155	example, it is not easy to find the correct path to the perl interpreter,	322	# in $TEMPLATE.
156	and all modules have to be loaded from disk again. Long running processes	323	use AnyEvent::Fork::Template;
157	might run into problems when perl is upgraded for example.
158		324
159	This module supports creating pre-initialised perl processes to be used	325	# do not put code outside of BEGIN blocks until here
160	as template, and also tries hard to identify the correct path to the perl
161	interpreter. With a cooperative main program, exec'ing the interpreter
162	might not even be necessary.
163		326
164	=item Forking might be impossible when a program is running. For example,	327	# now use the $TEMPLATE process in any way you like
165	POSIX makes it almost impossible to fork from a multi-threaded program and
166	do anything useful in the child - strictly speaking, if your perl program
167	uses posix threads (even indirectly via e.g. L<IO::AIO> or L<threads>),
168	you cannot call fork on the perl level anymore, at all.
169		328
170	This module can safely fork helper processes at any time, by calling	329	# for example: create 10 worker processes
171	fork+exec in C, in a POSIX-compatible way.	330	my @worker;
172		331	my $cv = AE::cv;
173	=item Parallel processing with fork might be inconvenient or difficult	332	for (1..10) {
174	to implement. For example, when a program uses an event loop and creates	333	$cv->begin;
175	watchers it becomes very hard to use the event loop from a child	334	$TEMPLATE->fork->send_arg ($_)->run ("worker_run", sub {
176	program, as the watchers already exist but are only meaningful in the	335	push @worker, shift;
177	parent. Worse, a module might want to use such a system, not knowing	336	$cv->end;
178	whether another module or the main program also does, leading to problems.	337	});
179		338	}
180	This module only lets the main program create pools by forking (because	339	$cv->recv;
181	only the main program can know when it is still safe to do so) - all other
182	pools are created by fork+exec, after which such modules can again be
183	loaded.
184
185	=back
186		340
187	=head1 CONCEPTS	341	=head1 CONCEPTS
188		342
189	This module can create new processes either by executing a new perl	343	This module can create new processes either by executing a new perl
190	process, or by forking from an existing "template" process.	344	process, or by forking from an existing "template" process.
		345
		346	All these processes are called "child processes" (whether they are direct
		347	children or not), while the process that manages them is called the
		348	"parent process".
191		349
192	Each such process comes with its own file handle that can be used to	350	Each such process comes with its own file handle that can be used to
193	communicate with it (it's actually a socket - one end in the new process,	351	communicate with it (it's actually a socket - one end in the new process,
194	one end in the main process), and among the things you can do in it are	352	one end in the main process), and among the things you can do in it are
195	load modules, fork new processes, send file handles to it, and execute	353	load modules, fork new processes, send file handles to it, and execute
…		…
269	my ($fork_fh) = @_;	427	my ($fork_fh) = @_;
270	});	428	});
271		429
272	=back	430	=back
273		431
274	=head1 FUNCTIONS	432	=head1 THE C<AnyEvent::Fork> CLASS
		433
		434	This module exports nothing, and only implements a single class -
		435	C<AnyEvent::Fork>.
		436
		437	There are two class constructors that both create new processes - C<new>
		438	and C<new_exec>. The C<fork> method creates a new process by forking an
		439	existing one and could be considered a third constructor.
		440
		441	Most of the remaining methods deal with preparing the new process, by
		442	loading code, evaluating code and sending data to the new process. They
		443	usually return the process object, so you can chain method calls.
		444
		445	If a process object is destroyed before calling its C<run> method, then
		446	the process simply exits. After C<run> is called, all responsibility is
		447	passed to the specified function.
		448
		449	As long as there is any outstanding work to be done, process objects
		450	resist being destroyed, so there is no reason to store them unless you
		451	need them later - configure and forget works just fine.
275		452
276	=over 4	453	=over 4
277		454
278	=cut	455	=cut
279		456
…		…
286	use AnyEvent;	463	use AnyEvent;
287	use AnyEvent::Util ();	464	use AnyEvent::Util ();
288		465
289	use IO::FDPass;	466	use IO::FDPass;
290		467
291	our $VERSION = 0.5;	468	our $VERSION = 1.2;
292
293	our $PERL; # the path to the perl interpreter, deduces with various forms of magic
294
295	=item my $pool = new AnyEvent::Fork key => value...
296
297	Create a new process pool. The following named parameters are supported:
298
299	=over 4
300
301	=back
302
303	=cut
304		469
305	# the early fork template process	470	# the early fork template process
306	our $EARLY;	471	our $EARLY;
307		472
308	# the empty template process	473	# the empty template process
309	our $TEMPLATE;	474	our $TEMPLATE;
		475
		476	sub QUEUE() { 0 }
		477	sub FH() { 1 }
		478	sub WW() { 2 }
		479	sub PID() { 3 }
		480	sub CB() { 4 }
		481
		482	sub _new {
		483	my ($self, $fh, $pid) = @_;
		484
		485	AnyEvent::Util::fh_nonblocking $fh, 1;
		486
		487	$self = bless [
		488	[], # write queue - strings or fd's
		489	$fh,
		490	undef, # AE watcher
		491	$pid,
		492	], $self;
		493
		494	$self
		495	}
310		496
311	sub _cmd {	497	sub _cmd {
312	my $self = shift;	498	my $self = shift;
313		499
314	# ideally, we would want to use "a (w/a)*" as format string, but perl	500	# ideally, we would want to use "a (w/a)*" as format string, but perl
315	# versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack	501	# versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack
316	# it.	502	# it.
317	push @{ $self->[2] }, pack "a L/a*", $_[0], $_[1];	503	push @{ $self->[QUEUE] }, pack "a L/a*", $_[0], $_[1];
318		504
319	$self->[3] \|\|= AE::io $self->[1], 1, sub {	505	$self->[WW] \|\|= AE::io $self->[FH], 1, sub {
320	do {	506	do {
321	# send the next "thing" in the queue - either a reference to an fh,	507	# send the next "thing" in the queue - either a reference to an fh,
322	# or a plain string.	508	# or a plain string.
323		509
324	if (ref $self->[2][0]) {	510	if (ref $self->[QUEUE][0]) {
325	# send fh	511	# send fh
326	unless (IO::FDPass::send fileno $self->[1], fileno ${ $self->[2][0] }) {	512	unless (IO::FDPass::send fileno $self->[FH], fileno ${ $self->[QUEUE][0] }) {
327	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;	513	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;
328	undef $self->[3];	514	undef $self->[WW];
329	die "AnyEvent::Fork: file descriptor send failure: $!";	515	die "AnyEvent::Fork: file descriptor send failure: $!";
330	}	516	}
331		517
332	shift @{ $self->[2] };	518	shift @{ $self->[QUEUE] };
333		519
334	} else {	520	} else {
335	# send string	521	# send string
336	my $len = syswrite $self->[1], $self->[2][0];	522	my $len = syswrite $self->[FH], $self->[QUEUE][0];
337		523
338	unless ($len) {	524	unless ($len) {
339	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;	525	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;
340	undef $self->[3];	526	undef $self->[WW];
341	die "AnyEvent::Fork: command write failure: $!";	527	die "AnyEvent::Fork: command write failure: $!";
342	}	528	}
343		529
344	substr $self->[2][0], 0, $len, "";	530	substr $self->[QUEUE][0], 0, $len, "";
345	shift @{ $self->[2] } unless length $self->[2][0];	531	shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];
346	}	532	}
347	} while @{ $self->[2] };	533	} while @{ $self->[QUEUE] };
348		534
349	# everything written	535	# everything written
350	undef $self->[3];	536	undef $self->[WW];
351		537
352	# invoke run callback, if any	538	# invoke run callback, if any
353	$self->[4]->($self->[1]) if $self->[4];	539	if ($self->[CB]) {
		540	$self->[CB]->($self->[FH]);
		541	@$self = ();
		542	}
354	};	543	};
355		544
356	() # make sure we don't leak the watcher	545	() # make sure we don't leak the watcher
357	}
358
359	sub _new {
360	my ($self, $fh, $pid) = @_;
361
362	AnyEvent::Util::fh_nonblocking $fh, 1;
363
364	$self = bless [
365	$pid,
366	$fh,
367	[], # write queue - strings or fd's
368	undef, # AE watcher
369	], $self;
370
371	$self
372	}	546	}
373		547
374	# fork template from current process, used by AnyEvent::Fork::Early/Template	548	# fork template from current process, used by AnyEvent::Fork::Early/Template
375	sub _new_fork {	549	sub _new_fork {
376	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;	550	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;
…		…
381	if ($pid eq 0) {	555	if ($pid eq 0) {
382	require AnyEvent::Fork::Serve;	556	require AnyEvent::Fork::Serve;
383	$AnyEvent::Fork::Serve::OWNER = $parent;	557	$AnyEvent::Fork::Serve::OWNER = $parent;
384	close $fh;	558	close $fh;
385	$0 = "$_[1] of $parent";	559	$0 = "$_[1] of $parent";
386	$SIG{CHLD} = 'IGNORE';
387	AnyEvent::Fork::Serve::serve ($slave);	560	AnyEvent::Fork::Serve::serve ($slave);
388	exit 0;	561	exit 0;
389	} elsif (!$pid) {	562	} elsif (!$pid) {
390	die "AnyEvent::Fork::Early/Template: unable to fork template process: $!";	563	die "AnyEvent::Fork::Early/Template: unable to fork template process: $!";
391	}	564	}
…		…
398	Create a new "empty" perl interpreter process and returns its process	571	Create a new "empty" perl interpreter process and returns its process
399	object for further manipulation.	572	object for further manipulation.
400		573
401	The new process is forked from a template process that is kept around	574	The new process is forked from a template process that is kept around
402	for this purpose. When it doesn't exist yet, it is created by a call to	575	for this purpose. When it doesn't exist yet, it is created by a call to
403	C<new_exec> and kept around for future calls.	576	C<new_exec> first and then stays around for future calls.
404
405	When the process object is destroyed, it will release the file handle
406	that connects it with the new process. When the new process has not yet
407	called C<run>, then the process will exit. Otherwise, what happens depends
408	entirely on the code that is executed.
409		577
410	=cut	578	=cut
411		579
412	sub new {	580	sub new {
413	my $class = shift;	581	my $class = shift;
…		…
450		618
451	You should use C<new> whenever possible, except when having a template	619	You should use C<new> whenever possible, except when having a template
452	process around is unacceptable.	620	process around is unacceptable.
453		621
454	The path to the perl interpreter is divined using various methods - first	622	The path to the perl interpreter is divined using various methods - first
455	C<$^X> is investigated to see if the path ends with something that sounds	623	C<$^X> is investigated to see if the path ends with something that looks
456	as if it were the perl interpreter. Failing this, the module falls back to	624	as if it were the perl interpreter. Failing this, the module falls back to
457	using C<$Config::Config{perlpath}>.	625	using C<$Config::Config{perlpath}>.
458		626
		627	The path to perl can also be overriden by setting the global variable
		628	C<$AnyEvent::Fork::PERL> - it's value will be used for all subsequent
		629	invocations.
		630
459	=cut	631	=cut
		632
		633	our $PERL;
460		634
461	sub new_exec {	635	sub new_exec {
462	my ($self) = @_;	636	my ($self) = @_;
463		637
464	return $EARLY->fork	638	return $EARLY->fork
465	if $EARLY;	639	if $EARLY;
466		640
		641	unless (defined $PERL) {
467	# first find path of perl	642	# first find path of perl
468	my $perl = $;	643	my $perl = $^X;
469		644
470	# first we try $^X, but the path must be absolute (always on win32), and end in sth.	645	# first we try $^X, but the path must be absolute (always on win32), and end in sth.
471	# that looks like perl. this obviously only works for posix and win32	646	# that looks like perl. this obviously only works for posix and win32
472	unless (	647	unless (
473	($^O eq "MSWin32" \|\| $perl =~ m%^/%)	648	($^O eq "MSWin32" \|\| $perl =~ m%^/%)
474	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i	649	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i
475	) {	650	) {
476	# if it doesn't look perlish enough, try Config	651	# if it doesn't look perlish enough, try Config
477	require Config;	652	require Config;
478	$perl = $Config::Config{perlpath};	653	$perl = $Config::Config{perlpath};
479	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;	654	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;
		655	}
		656
		657	$PERL = $perl;
480	}	658	}
481		659
482	require Proc::FastSpawn;	660	require Proc::FastSpawn;
483		661
484	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;	662	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;
…		…
492	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;	670	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;
493	my %env = %ENV;	671	my %env = %ENV;
494	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;	672	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;
495		673
496	my $pid = Proc::FastSpawn::spawn (	674	my $pid = Proc::FastSpawn::spawn (
497	$perl,	675	$PERL,
498	["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],	676	["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],
499	[map "$_=$env{$_}", keys %env],	677	[map "$_=$env{$_}", keys %env],
500	) or die "unable to spawn AnyEvent::Fork server: $!";	678	) or die "unable to spawn AnyEvent::Fork server: $!";
501		679
502	$self->_new ($fh, $pid)	680	$self->_new ($fh, $pid)
503	}	681	}
504		682
505	=item $pid = $proc->pid	683	=item $pid = $proc->pid
506		684
507	Returns the process id of the process I<iff it is a direct child of the	685	Returns the process id of the process I<iff it is a direct child of the
508	process> running AnyEvent::Fork, and C<undef> otherwise.	686	process running AnyEvent::Fork>, and C<undef> otherwise. As a general
		687	rule (that you cannot rely upon), processes created via C<new_exec>,
		688	L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template> are direct
		689	children, while all other processes are not.
509		690
510	Normally, only processes created via C<< AnyEvent::Fork->new_exec >> and	691	Or in other words, you do not normally have to take care of zombies for
511	L<AnyEvent::Fork::Template> are direct children, and you are responsible	692	processes created via C<new>, but when in doubt, or zombies are a problem,
512	to clean up their zombies when they die.	693	you need to check whether a process is a diretc child by calling this
513		694	method, and possibly creating a child watcher or reap it manually.
514	All other processes are not direct children, and will be cleaned up by
515	AnyEvent::Fork.
516		695
517	=cut	696	=cut
518		697
519	sub pid {	698	sub pid {
520	$_[0][0]	699	$_[0][PID]
521	}	700	}
522		701
523	=item $proc = $proc->eval ($perlcode, @args)	702	=item $proc = $proc->eval ($perlcode, @args)
524		703
525	Evaluates the given C<$perlcode> as ... perl code, while setting C<@_> to	704	Evaluates the given C<$perlcode> as ... Perl code, while setting C<@_> to
526	the strings specified by C<@args>, in the "main" package.	705	the strings specified by C<@args>, in the "main" package.
527		706
528	This call is meant to do any custom initialisation that might be required	707	This call is meant to do any custom initialisation that might be required
529	(for example, the C<require> method uses it). It's not supposed to be used	708	(for example, the C<require> method uses it). It's not supposed to be used
530	to completely take over the process, use C<run> for that.	709	to completely take over the process, use C<run> for that.
531		710
532	The code will usually be executed after this call returns, and there is no	711	The code will usually be executed after this call returns, and there is no
533	way to pass anything back to the calling process. Any evaluation errors	712	way to pass anything back to the calling process. Any evaluation errors
534	will be reported to stderr and cause the process to exit.	713	will be reported to stderr and cause the process to exit.
535		714
536	If you want to execute some code to take over the process (see the	715	If you want to execute some code (that isn't in a module) to take over the
537	"fork+exec" example in the SYNOPSIS), you should compile a function via	716	process, you should compile a function via C<eval> first, and then call
538	C<eval> first, and then call it via C<run>. This also gives you access to	717	it via C<run>. This also gives you access to any arguments passed via the
539	any arguments passed via the C<send_xxx> methods, such as file handles.	718	C<send_xxx> methods, such as file handles. See the L<use AnyEvent::Fork as
		719	a faster fork+exec> example to see it in action.
540		720
541	Returns the process object for easy chaining of method calls.	721	Returns the process object for easy chaining of method calls.
542		722
543	=cut	723	=cut
544		724
…		…
570	=item $proc = $proc->send_fh ($handle, ...)	750	=item $proc = $proc->send_fh ($handle, ...)
571		751
572	Send one or more file handles (I<not> file descriptors) to the process,	752	Send one or more file handles (I<not> file descriptors) to the process,
573	to prepare a call to C<run>.	753	to prepare a call to C<run>.
574		754
575	The process object keeps a reference to the handles until this is done,	755	The process object keeps a reference to the handles until they have
576	so you must not explicitly close the handles. This is most easily	756	been passed over to the process, so you must not explicitly close the
577	accomplished by simply not storing the file handles anywhere after passing	757	handles. This is most easily accomplished by simply not storing the file
578	them to this method.	758	handles anywhere after passing them to this method - when AnyEvent::Fork
		759	is finished using them, perl will automatically close them.
579		760
580	Returns the process object for easy chaining of method calls.	761	Returns the process object for easy chaining of method calls.
581		762
582	Example: pass a file handle to a process, and release it without	763	Example: pass a file handle to a process, and release it without
583	closing. It will be closed automatically when it is no longer used.	764	closing. It will be closed automatically when it is no longer used.
…		…
590	sub send_fh {	771	sub send_fh {
591	my ($self, @fh) = @_;	772	my ($self, @fh) = @_;
592		773
593	for my $fh (@fh) {	774	for my $fh (@fh) {
594	$self->_cmd ("h");	775	$self->_cmd ("h");
595	push @{ $self->[2] }, \$fh;	776	push @{ $self->[QUEUE] }, \$fh;
596	}	777	}
597		778
598	$self	779	$self
599	}	780	}
600		781
601	=item $proc = $proc->send_arg ($string, ...)	782	=item $proc = $proc->send_arg ($string, ...)
602		783
603	Send one or more argument strings to the process, to prepare a call to	784	Send one or more argument strings to the process, to prepare a call to
604	C<run>. The strings can be any octet string.	785	C<run>. The strings can be any octet strings.
605		786
606	The protocol is optimised to pass a moderate number of relatively short	787	The protocol is optimised to pass a moderate number of relatively short
607	strings - while you can pass up to 4GB of data in one go, this is more	788	strings - while you can pass up to 4GB of data in one go, this is more
608	meant to pass some ID information or other startup info, not big chunks of	789	meant to pass some ID information or other startup info, not big chunks of
609	data.	790	data.
…		…
625	Enter the function specified by the function name in C<$func> in the	806	Enter the function specified by the function name in C<$func> in the
626	process. The function is called with the communication socket as first	807	process. The function is called with the communication socket as first
627	argument, followed by all file handles and string arguments sent earlier	808	argument, followed by all file handles and string arguments sent earlier
628	via C<send_fh> and C<send_arg> methods, in the order they were called.	809	via C<send_fh> and C<send_arg> methods, in the order they were called.
629		810
		811	The process object becomes unusable on return from this function - any
		812	further method calls result in undefined behaviour.
		813
630	The function name should be fully qualified, but if it isn't, it will be	814	The function name should be fully qualified, but if it isn't, it will be
631	looked up in the main package.	815	looked up in the C<main> package.
632		816
633	If the called function returns, doesn't exist, or any error occurs, the	817	If the called function returns, doesn't exist, or any error occurs, the
634	process exits.	818	process exits.
635		819
636	Preparing the process is done in the background - when all commands have	820	Preparing the process is done in the background - when all commands have
637	been sent, the callback is invoked with the local communications socket	821	been sent, the callback is invoked with the local communications socket
638	as argument. At this point you can start using the socket in any way you	822	as argument. At this point you can start using the socket in any way you
639	like.	823	like.
640		824
641	The process object becomes unusable on return from this function - any
642	further method calls result in undefined behaviour.
643
644	If the communication socket isn't used, it should be closed on both sides,	825	If the communication socket isn't used, it should be closed on both sides,
645	to save on kernel memory.	826	to save on kernel memory.
646		827
647	The socket is non-blocking in the parent, and blocking in the newly	828	The socket is non-blocking in the parent, and blocking in the newly
648	created process. The close-on-exec flag is set in both.	829	created process. The close-on-exec flag is set in both.
649		830
650	Even if not used otherwise, the socket can be a good indicator for the	831	Even if not used otherwise, the socket can be a good indicator for the
651	existence of the process - if the other process exits, you get a readable	832	existence of the process - if the other process exits, you get a readable
652	event on it, because exiting the process closes the socket (if it didn't	833	event on it, because exiting the process closes the socket (if it didn't
653	create any children using fork).	834	create any children using fork).
		835
		836	=over 4
		837
		838	=item Compatibility to L<AnyEvent::Fork::Remote>
		839
		840	If you want to write code that works with both this module and
		841	L<AnyEvent::Fork::Remote>, you need to write your code so that it assumes
		842	there are two file handles for communications, which might not be unix
		843	domain sockets. The C<run> function should start like this:
		844
		845	sub run {
		846	my ($rfh, @args) = @_; # @args is your normal arguments
		847	my $wfh = fileno $rfh ? $rfh : *STDOUT;
		848
		849	# now use $rfh for reading and $wfh for writing
		850	}
		851
		852	This checks whether the passed file handle is, in fact, the process
		853	C<STDIN> handle. If it is, then the function was invoked visa
		854	L<AnyEvent::Fork::Remote>, so STDIN should be used for reading and
		855	C<STDOUT> should be used for writing.
		856
		857	In all other cases, the function was called via this module, and there is
		858	only one file handle that should be sued for reading and writing.
		859
		860	=back
654		861
655	Example: create a template for a process pool, pass a few strings, some	862	Example: create a template for a process pool, pass a few strings, some
656	file handles, then fork, pass one more string, and run some code.	863	file handles, then fork, pass one more string, and run some code.
657		864
658	my $pool = AnyEvent::Fork	865	my $pool = AnyEvent::Fork
…		…
686	=cut	893	=cut
687		894
688	sub run {	895	sub run {
689	my ($self, $func, $cb) = @_;	896	my ($self, $func, $cb) = @_;
690		897
691	$self->[4] = $cb;	898	$self->[CB] = $cb;
692	$self->_cmd (r => $func);	899	$self->_cmd (r => $func);
		900	}
		901
		902	=back
		903
		904	=head2 EXPERIMENTAL METHODS
		905
		906	These methods might go away completely or change behaviour, at any time.
		907
		908	=over 4
		909
		910	=item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED
		911
		912	Flushes all commands out to the process and then calls the callback with
		913	the communications socket.
		914
		915	The process object becomes unusable on return from this function - any
		916	further method calls result in undefined behaviour.
		917
		918	The point of this method is to give you a file handle that you can pass
		919	to another process. In that other process, you can call C<new_from_fh
		920	AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it,
		921	thereby effectively passing a fork object to another process.
		922
		923	=cut
		924
		925	sub to_fh {
		926	my ($self, $cb) = @_;
		927
		928	$self->[CB] = $cb;
		929
		930	unless ($self->[WW]) {
		931	$self->[CB]->($self->[FH]);
		932	@$self = ();
		933	}
		934	}
		935
		936	=item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED
		937
		938	Takes a file handle originally rceeived by the C<to_fh> method and creates
		939	a new C<AnyEvent:Fork> object. The child process itself will not change in
		940	any way, i.e. it will keep all the modifications done to it before calling
		941	C<to_fh>.
		942
		943	The new object is very much like the original object, except that the
		944	C<pid> method will return C<undef> even if the process is a direct child.
		945
		946	=cut
		947
		948	sub new_from_fh {
		949	my ($class, $fh) = @_;
		950
		951	$class->_new ($fh)
693	}	952	}
694		953
695	=back	954	=back
696		955
697	=head1 PERFORMANCE	956	=head1 PERFORMANCE
…		…
707		966
708	2079 new processes per second, using manual socketpair + fork	967	2079 new processes per second, using manual socketpair + fork
709		968
710	Then I did the same thing, but instead of calling fork, I called	969	Then I did the same thing, but instead of calling fork, I called
711	AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the	970	AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the
712	socket form the child to close on exit. This does the same thing as manual	971	socket from the child to close on exit. This does the same thing as manual
713	socket pair + fork, except that what is forked is the template process	972	socket pair + fork, except that what is forked is the template process
714	(2440kB), and the socket needs to be passed to the server at the other end	973	(2440kB), and the socket needs to be passed to the server at the other end
715	of the socket first.	974	of the socket first.
716		975
717	2307 new processes per second, using AnyEvent::Fork->new	976	2307 new processes per second, using AnyEvent::Fork->new
…		…
722	479 vfork+execs per second, using AnyEvent::Fork->new_exec	981	479 vfork+execs per second, using AnyEvent::Fork->new_exec
723		982
724	So how can C<< AnyEvent->new >> be faster than a standard fork, even	983	So how can C<< AnyEvent->new >> be faster than a standard fork, even
725	though it uses the same operations, but adds a lot of overhead?	984	though it uses the same operations, but adds a lot of overhead?
726		985
727	The difference is simply the process size: forking the 6MB process takes	986	The difference is simply the process size: forking the 5MB process takes
728	so much longer than forking the 2.5MB template process that the overhead	987	so much longer than forking the 2.5MB template process that the extra
729	introduced is canceled out.	988	overhead is canceled out.
730		989
731	If the benchmark process grows, the normal fork becomes even slower:	990	If the benchmark process grows, the normal fork becomes even slower:
732		991
733	1340 new processes, manual fork in a 20MB process	992	1340 new processes, manual fork of a 20MB process
734	731 new processes, manual fork in a 200MB process	993	731 new processes, manual fork of a 200MB process
735	235 new processes, manual fork in a 2000MB process	994	235 new processes, manual fork of a 2000MB process
736		995
737	What that means (to me) is that I can use this module without having a	996	What that means (to me) is that I can use this module without having a bad
738	very bad conscience because of the extra overhead required to start new	997	conscience because of the extra overhead required to start new processes.
739	processes.
740		998
741	=head1 TYPICAL PROBLEMS	999	=head1 TYPICAL PROBLEMS
742		1000
743	This section lists typical problems that remain. I hope by recognising	1001	This section lists typical problems that remain. I hope by recognising
744	them, most can be avoided.	1002	them, most can be avoided.
745		1003
746	=over 4	1004	=over 4
747		1005
748	=item "leaked" file descriptors for exec'ed processes	1006	=item leaked file descriptors for exec'ed processes
749		1007
750	POSIX systems inherit file descriptors by default when exec'ing a new	1008	POSIX systems inherit file descriptors by default when exec'ing a new
751	process. While perl itself laudably sets the close-on-exec flags on new	1009	process. While perl itself laudably sets the close-on-exec flags on new
752	file handles, most C libraries don't care, and even if all cared, it's	1010	file handles, most C libraries don't care, and even if all cared, it's
753	often not possible to set the flag in a race-free manner.	1011	often not possible to set the flag in a race-free manner.
…		…
773	libraries or the code that leaks those file descriptors.	1031	libraries or the code that leaks those file descriptors.
774		1032
775	Fortunately, most of these leaked descriptors do no harm, other than	1033	Fortunately, most of these leaked descriptors do no harm, other than
776	sitting on some resources.	1034	sitting on some resources.
777		1035
778	=item "leaked" file descriptors for fork'ed processes	1036	=item leaked file descriptors for fork'ed processes
779		1037
780	Normally, L<AnyEvent::Fork> does start new processes by exec'ing them,	1038	Normally, L<AnyEvent::Fork> does start new processes by exec'ing them,
781	which closes file descriptors not marked for being inherited.	1039	which closes file descriptors not marked for being inherited.
782		1040
783	However, L<AnyEvent::Fork::Early> and L<AnyEvent::Fork::Template> offer	1041	However, L<AnyEvent::Fork::Early> and L<AnyEvent::Fork::Template> offer
…		…
792		1050
793	The solution is to either not load these modules before use'ing	1051	The solution is to either not load these modules before use'ing
794	L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template>, or to delay	1052	L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template>, or to delay
795	initialising them, for example, by calling C<init Gtk2> manually.	1053	initialising them, for example, by calling C<init Gtk2> manually.
796		1054
797	=item exit runs destructors	1055	=item exiting calls object destructors
798		1056
799	This only applies to users of Lc<AnyEvent::Fork:Early> and	1057	This only applies to users of L<AnyEvent::Fork:Early> and
800	L<AnyEvent::Fork::Template>.	1058	L<AnyEvent::Fork::Template>, or when initialising code creates objects
		1059	that reference external resources.
801		1060
802	When a process created by AnyEvent::Fork exits, it might do so by calling	1061	When a process created by AnyEvent::Fork exits, it might do so by calling
803	exit, or simply letting perl reach the end of the program. At which point	1062	exit, or simply letting perl reach the end of the program. At which point
804	Perl runs all destructors.	1063	Perl runs all destructors.
805		1064
…		…
824	to make it so, mostly due to the bloody broken perl that nobody seems to	1083	to make it so, mostly due to the bloody broken perl that nobody seems to
825	care about. The fork emulation is a bad joke - I have yet to see something	1084	care about. The fork emulation is a bad joke - I have yet to see something
826	useful that you can do with it without running into memory corruption	1085	useful that you can do with it without running into memory corruption
827	issues or other braindamage. Hrrrr.	1086	issues or other braindamage. Hrrrr.
828		1087
829	Cygwin perl is not supported at the moment, as it should implement fd	1088	Since fork is endlessly broken on win32 perls (it doesn't even remotely
830	passing, but doesn't, and rolling my own is hard, as cygwin doesn't	1089	work within it's documented limits) and quite obviously it's not getting
831	support enough functionality to do it.	1090	improved any time soon, the best way to proceed on windows would be to
		1091	always use C<new_exec> and thus never rely on perl's fork "emulation".
		1092
		1093	Cygwin perl is not supported at the moment due to some hilarious
		1094	shortcomings of its API - see L<IO::FDPoll> for more details. If you never
		1095	use C<send_fh> and always use C<new_exec> to create processes, it should
		1096	work though.
		1097
		1098	=head1 USING AnyEvent::Fork IN SUBPROCESSES
		1099
		1100	AnyEvent::Fork itself cannot generally be used in subprocesses. As long as
		1101	only one process ever forks new processes, sharing the template processes
		1102	is possible (you could use a pipe as a lock by writing a byte into it to
		1103	unlock, and reading the byte to lock for example)
		1104
		1105	To make concurrent calls possible after fork, you should get rid of the
		1106	template and early fork processes. AnyEvent::Fork will create a new
		1107	template process as needed.
		1108
		1109	undef $AnyEvent::Fork::EARLY;
		1110	undef $AnyEvent::Fork::TEMPLATE;
		1111
		1112	It doesn't matter whether you get rid of them in the parent or child after
		1113	a fork.
832		1114
833	=head1 SEE ALSO	1115	=head1 SEE ALSO
834		1116
835	L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter),	1117	L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all
		1118	(part of this distribution).
		1119
836	L<AnyEvent::Fork::Template> (to create a process by forking the main	1120	L<AnyEvent::Fork::Template>, to create a process by forking the main
837	program at a convenient time).	1121	program at a convenient time (part of this distribution).
838		1122
839	=head1 AUTHOR	1123	L<AnyEvent::Fork::Remote>, for another way to create processes that is
		1124	mostly compatible to this module and modules building on top of it, but
		1125	works better with remote processes.
		1126
		1127	L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN).
		1128
		1129	L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN).
		1130
		1131	=head1 AUTHOR AND CONTACT INFORMATION
840		1132
841	Marc Lehmann <schmorp@schmorp.de>	1133	Marc Lehmann <schmorp@schmorp.de>
842	http://home.schmorp.de/	1134	http://software.schmorp.de/pkg/AnyEvent-Fork
843		1135
844	=cut	1136	=cut
845		1137
846	1	1138	1
847		1139

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Comparing AnyEvent-Fork/Fork.pm (file contents): Revision 1.23 by root, Sat Apr 6 08:29:43 2013 UTC vs. Revision 1.63 by root, Wed Nov 26 13:36:18 2014 UTC

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Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.23 by root, Sat Apr 6 08:29:43 2013 UTC vs.
Revision 1.63 by root, Wed Nov 26 13:36:18 2014 UTC