[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 1.67 by root, Thu May 12 16:54:01 2016 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
		183	This is where the wall of text ends and code speaks.
		184
10	# create a single new process, tell it to run your worker function	185	=head2 Create a single new process, tell it to run your worker function.
11		186
12	AnyEvent::Fork	187	AnyEvent::Fork
13	->new	188	->new
14	->require ("MyModule")	189	->require ("MyModule")
15	->run ("MyModule::worker, sub {	190	->run ("MyModule::worker, sub {
…		…
17		192
18	# now $master_filehandle is connected to the	193	# now $master_filehandle is connected to the
19	# $slave_filehandle in the new process.	194	# $slave_filehandle in the new process.
20	});	195	});
21		196
22	# MyModule::worker might look like this	197	C<MyModule> might look like this:
		198
		199	package MyModule;
		200
23	sub MyModule::worker {	201	sub worker {
24	my ($slave_filehandle) = @_;	202	my ($slave_filehandle) = @_;
25		203
26	# now $slave_filehandle is connected to the $master_filehandle	204	# now $slave_filehandle is connected to the $master_filehandle
27	# in the original prorcess. have fun!	205	# in the original process. have fun!
28	}	206	}
29		207
30	##################################################################
31	# create a pool of server processes all accepting on the same socket	208	=head2 Create a pool of server processes all accepting on the same socket.
32		209
33	# create listener socket	210	# create listener socket
34	my $listener = ...;	211	my $listener = ...;
35		212
36	# create a pool template, initialise it and give it the socket	213	# create a pool template, initialise it and give it the socket
…		…
48	}	225	}
49		226
50	# now do other things - maybe use the filehandle provided by run	227	# now do other things - maybe use the filehandle provided by run
51	# to wait for the processes to die. or whatever.	228	# to wait for the processes to die. or whatever.
52		229
53	# My::Server::run might look like this	230	C<My::Server> might look like this:
54	sub My::Server::run {	231
		232	package My::Server;
		233
		234	sub run {
55	my ($slave, $listener, $id) = @_;	235	my ($slave, $listener, $id) = @_;
56		236
57	close $slave; # we do not use the socket, so close it to save resources	237	close $slave; # we do not use the socket, so close it to save resources
58		238
59	# we could go ballistic and use e.g. AnyEvent here, or IO::AIO,	239	# we could go ballistic and use e.g. AnyEvent here, or IO::AIO,
…		…
61	while (my $socket = $listener->accept) {	241	while (my $socket = $listener->accept) {
62	# do sth. with new socket	242	# do sth. with new socket
63	}	243	}
64	}	244	}
65		245
66	##################################################################
67	# use AnyEvent::Fork as a faster fork+exec	246	=head2 use AnyEvent::Fork as a faster fork+exec
68		247
69	# this runs /bin/echo hi, with stdout redirected to /tmp/log	248	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	249	and standard error redirected to the communications socket. It is usually
71	# than fork+exec, but still let's you prepare the environment.	250	faster than fork+exec, but still lets you prepare the environment.
72		251
73	open my $output, ">/tmp/log" or die "$!";	252	open my $output, ">/tmp/log" or die "$!";
74		253
75	AnyEvent::Fork	254	AnyEvent::Fork
76	->new	255	->new
77	->eval ('	256	->eval ('
		257	# compile a helper function for later use
78	sub run {	258	sub run {
79	my ($fh, $output, @cmd) = @_;	259	my ($fh, $output, @cmd) = @_;
80		260
81	# perl will clear close-on-exec on STDOUT/STDERR	261	# perl will clear close-on-exec on STDOUT/STDERR
82	open STDOUT, ">&", $output or die;	262	open STDOUT, ">&", $output or die;
…		…
89	->send_arg ("/bin/echo", "hi")	269	->send_arg ("/bin/echo", "hi")
90	->run ("run", my $cv = AE::cv);	270	->run ("run", my $cv = AE::cv);
91		271
92	my $stderr = $cv->recv;	272	my $stderr = $cv->recv;
93		273
94	=head1 DESCRIPTION	274	=head2 For stingy users: put the worker code into a C<DATA> section.
95		275
96	This module allows you to create new processes, without actually forking	276	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	277	C<DATA> section of your module (or program):
98	preserving most of the advantages of fork.
99		278
100	It can be used to create new worker processes or new independent	279	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		280
106	Special care has been taken to make this module useful from other modules,	281	AnyEvent::Fork
107	while still supporting specialised environments such as L<App::Staticperl>	282	->new
108	or L<PAR::Packer>.	283	->eval (do { local $/; <DATA> })
		284	->run ("doit", sub { ... });
109		285
110	=head1 WHAT THIS MODULE IS NOT	286	__DATA__
111		287
112	This module only creates processes and lets you pass file handles and	288	sub doit {
113	strings to it, and run perl code. It does not implement any kind of RPC -	289	... do something!
114	there is no back channel from the process back to you, and there is no RPC	290	}
115	or message passing going on.
116		291
117	If you need some form of RPC, you can either implement it yourself	292	=head2 For stingy standalone programs: do not rely on external files at
118	in whatever way you like, use some message-passing module such	293	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		294
123	=head1 PROBLEM STATEMENT	295	For single-file scripts it can be inconvenient to rely on external
		296	files - even when using a C<DATA> section, you still need to C<exec> an
		297	external perl interpreter, which might not be available when using
		298	L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example.
124		299
125	There are two ways to implement parallel processing on UNIX like operating	300	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	301	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	302	forks the main program as a template process.
128	module tries to mitigate the disadvantages.
129		303
130	=over 4	304	Here is how your main program should look like:
131		305
132	=item Forking from a big process can be very slow (a 5GB process needs	306	#! 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		307
137	This module can help here by telling a small(er) helper process to fork,	308	# optional, as the very first thing.
138	or fork+exec instead.	309	# in case modules want to create their own processes.
		310	use AnyEvent::Fork::Early;
139		311
140	=item Forking usually creates a copy-on-write copy of the parent	312	# next, load all modules you need in your template process
141	process. Memory (for example, modules or data files that have been	313	use Example::My::Module
142	will not take additional memory). When exec'ing a new process, modules	314	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		315
148	This module allows the main program to do a controlled fork, and allows	316	# next, put your run function definition and anything else you
149	modules to exec processes safely at any time. When creating a custom	317	# need, but do not use code outside of BEGIN blocks.
150	process pool you can take advantage of data sharing via fork without	318	sub worker_run {
151	risking to share large dynamic data structures that will blow up child	319	my ($fh, @args) = @_;
152	memory usage.	320	...
		321	}
153		322
154	=item Exec'ing a new perl process might be difficult and slow. For	323	# now preserve everything so far as AnyEvent::Fork object
155	example, it is not easy to find the correct path to the perl interpreter,	324	# in $TEMPLATE.
156	and all modules have to be loaded from disk again. Long running processes	325	use AnyEvent::Fork::Template;
157	might run into problems when perl is upgraded for example.
158		326
159	This module supports creating pre-initialised perl processes to be used	327	# 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		328
164	=item Forking might be impossible when a program is running. For example,	329	# 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		330
170	This module can safely fork helper processes at any time, by calling	331	# for example: create 10 worker processes
171	fork+exec in C, in a POSIX-compatible way.	332	my @worker;
172		333	my $cv = AE::cv;
173	=item Parallel processing with fork might be inconvenient or difficult	334	for (1..10) {
174	to implement. For example, when a program uses an event loop and creates	335	$cv->begin;
175	watchers it becomes very hard to use the event loop from a child	336	$TEMPLATE->fork->send_arg ($_)->run ("worker_run", sub {
176	program, as the watchers already exist but are only meaningful in the	337	push @worker, shift;
177	parent. Worse, a module might want to use such a system, not knowing	338	$cv->end;
178	whether another module or the main program also does, leading to problems.	339	});
179		340	}
180	This module only lets the main program create pools by forking (because	341	$cv->recv;
181	only the main program can know when it is still safe to do so) - all other
182	pools are created by fork+exec, after which such modules can again be
183	loaded.
184
185	=back
186		342
187	=head1 CONCEPTS	343	=head1 CONCEPTS
188		344
189	This module can create new processes either by executing a new perl	345	This module can create new processes either by executing a new perl
190	process, or by forking from an existing "template" process.	346	process, or by forking from an existing "template" process.
		347
		348	All these processes are called "child processes" (whether they are direct
		349	children or not), while the process that manages them is called the
		350	"parent process".
191		351
192	Each such process comes with its own file handle that can be used to	352	Each such process comes with its own file handle that can be used to
193	communicate with it (it's actually a socket - one end in the new process,	353	communicate with it (it's actually a socket - one end in the new process,
194	one end in the main process), and among the things you can do in it are	354	one end in the main process), and among the things you can do in it are
195	load modules, fork new processes, send file handles to it, and execute	355	load modules, fork new processes, send file handles to it, and execute
…		…
269	my ($fork_fh) = @_;	429	my ($fork_fh) = @_;
270	});	430	});
271		431
272	=back	432	=back
273		433
274	=head1 FUNCTIONS	434	=head1 THE C<AnyEvent::Fork> CLASS
		435
		436	This module exports nothing, and only implements a single class -
		437	C<AnyEvent::Fork>.
		438
		439	There are two class constructors that both create new processes - C<new>
		440	and C<new_exec>. The C<fork> method creates a new process by forking an
		441	existing one and could be considered a third constructor.
		442
		443	Most of the remaining methods deal with preparing the new process, by
		444	loading code, evaluating code and sending data to the new process. They
		445	usually return the process object, so you can chain method calls.
		446
		447	If a process object is destroyed before calling its C<run> method, then
		448	the process simply exits. After C<run> is called, all responsibility is
		449	passed to the specified function.
		450
		451	As long as there is any outstanding work to be done, process objects
		452	resist being destroyed, so there is no reason to store them unless you
		453	need them later - configure and forget works just fine.
275		454
276	=over 4	455	=over 4
277		456
278	=cut	457	=cut
279		458
…		…
286	use AnyEvent;	465	use AnyEvent;
287	use AnyEvent::Util ();	466	use AnyEvent::Util ();
288		467
289	use IO::FDPass;	468	use IO::FDPass;
290		469
291	our $VERSION = 0.5;	470	our $VERSION = 1.3;
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		471
305	# the early fork template process	472	# the early fork template process
306	our $EARLY;	473	our $EARLY;
307		474
308	# the empty template process	475	# the empty template process
309	our $TEMPLATE;	476	our $TEMPLATE;
		477
		478	sub QUEUE() { 0 }
		479	sub FH() { 1 }
		480	sub WW() { 2 }
		481	sub PID() { 3 }
		482	sub CB() { 4 }
		483
		484	sub _new {
		485	my ($self, $fh, $pid) = @_;
		486
		487	AnyEvent::Util::fh_nonblocking $fh, 1;
		488
		489	$self = bless [
		490	[], # write queue - strings or fd's
		491	$fh,
		492	undef, # AE watcher
		493	$pid,
		494	], $self;
		495
		496	$self
		497	}
310		498
311	sub _cmd {	499	sub _cmd {
312	my $self = shift;	500	my $self = shift;
313		501
314	# ideally, we would want to use "a (w/a)*" as format string, but perl	502	# 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	503	# versions from at least 5.8.9 to 5.16.3 are all buggy and can't unpack
316	# it.	504	# it.
317	push @{ $self->[2] }, pack "a L/a*", $_[0], $_[1];	505	push @{ $self->[QUEUE] }, pack "a L/a*", $_[0], $_[1];
318		506
319	$self->[3] \|\|= AE::io $self->[1], 1, sub {	507	$self->[WW] \|\|= AE::io $self->[FH], 1, sub {
320	do {	508	do {
321	# send the next "thing" in the queue - either a reference to an fh,	509	# send the next "thing" in the queue - either a reference to an fh,
322	# or a plain string.	510	# or a plain string.
323		511
324	if (ref $self->[2][0]) {	512	if (ref $self->[QUEUE][0]) {
325	# send fh	513	# send fh
326	unless (IO::FDPass::send fileno $self->[1], fileno ${ $self->[2][0] }) {	514	unless (IO::FDPass::send fileno $self->[FH], fileno ${ $self->[QUEUE][0] }) {
327	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;	515	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;
328	undef $self->[3];	516	undef $self->[WW];
329	die "AnyEvent::Fork: file descriptor send failure: $!";	517	die "AnyEvent::Fork: file descriptor send failure: $!";
330	}	518	}
331		519
332	shift @{ $self->[2] };	520	shift @{ $self->[QUEUE] };
333		521
334	} else {	522	} else {
335	# send string	523	# send string
336	my $len = syswrite $self->[1], $self->[2][0];	524	my $len = syswrite $self->[FH], $self->[QUEUE][0];
337		525
338	unless ($len) {	526	unless ($len) {
339	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;	527	return if $! == Errno::EAGAIN \|\| $! == Errno::EWOULDBLOCK;
340	undef $self->[3];	528	undef $self->[WW];
341	die "AnyEvent::Fork: command write failure: $!";	529	die "AnyEvent::Fork: command write failure: $!";
342	}	530	}
343		531
344	substr $self->[2][0], 0, $len, "";	532	substr $self->[QUEUE][0], 0, $len, "";
345	shift @{ $self->[2] } unless length $self->[2][0];	533	shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];
346	}	534	}
347	} while @{ $self->[2] };	535	} while @{ $self->[QUEUE] };
348		536
349	# everything written	537	# everything written
350	undef $self->[3];	538	undef $self->[WW];
351		539
352	# invoke run callback, if any	540	# invoke run callback, if any
353	$self->[4]->($self->[1]) if $self->[4];	541	if ($self->[CB]) {
		542	$self->[CB]->($self->[FH]);
		543	@$self = ();
		544	}
354	};	545	};
355		546
356	() # make sure we don't leak the watcher	547	() # make sure we don't leak the watcher
357	}
358
359	sub _new {
360	my ($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	$self
372	}	548	}
373		549
374	# fork template from current process, used by AnyEvent::Fork::Early/Template	550	# fork template from current process, used by AnyEvent::Fork::Early/Template
375	sub _new_fork {	551	sub _new_fork {
376	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;	552	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;
…		…
381	if ($pid eq 0) {	557	if ($pid eq 0) {
382	require AnyEvent::Fork::Serve;	558	require AnyEvent::Fork::Serve;
383	$AnyEvent::Fork::Serve::OWNER = $parent;	559	$AnyEvent::Fork::Serve::OWNER = $parent;
384	close $fh;	560	close $fh;
385	$0 = "$_[1] of $parent";	561	$0 = "$_[1] of $parent";
386	$SIG{CHLD} = 'IGNORE';
387	AnyEvent::Fork::Serve::serve ($slave);	562	AnyEvent::Fork::Serve::serve ($slave);
388	exit 0;	563	exit 0;
389	} elsif (!$pid) {	564	} elsif (!$pid) {
390	die "AnyEvent::Fork::Early/Template: unable to fork template process: $!";	565	die "AnyEvent::Fork::Early/Template: unable to fork template process: $!";
391	}	566	}
…		…
398	Create a new "empty" perl interpreter process and returns its process	573	Create a new "empty" perl interpreter process and returns its process
399	object for further manipulation.	574	object for further manipulation.
400		575
401	The new process is forked from a template process that is kept around	576	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	577	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.	578	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		579
410	=cut	580	=cut
411		581
412	sub new {	582	sub new {
413	my $class = shift;	583	my $class = shift;
…		…
450		620
451	You should use C<new> whenever possible, except when having a template	621	You should use C<new> whenever possible, except when having a template
452	process around is unacceptable.	622	process around is unacceptable.
453		623
454	The path to the perl interpreter is divined using various methods - first	624	The path to the perl interpreter is divined using various methods - first
455	C<$^X> is investigated to see if the path ends with something that sounds	625	C<$^X> is investigated to see if the path ends with something that looks
456	as if it were the perl interpreter. Failing this, the module falls back to	626	as if it were the perl interpreter. Failing this, the module falls back to
457	using C<$Config::Config{perlpath}>.	627	using C<$Config::Config{perlpath}>.
458		628
		629	The path to perl can also be overriden by setting the global variable
		630	C<$AnyEvent::Fork::PERL> - it's value will be used for all subsequent
		631	invocations.
		632
459	=cut	633	=cut
		634
		635	our $PERL;
460		636
461	sub new_exec {	637	sub new_exec {
462	my ($self) = @_;	638	my ($self) = @_;
463		639
464	return $EARLY->fork	640	return $EARLY->fork
465	if $EARLY;	641	if $EARLY;
466		642
		643	unless (defined $PERL) {
467	# first find path of perl	644	# first find path of perl
468	my $perl = $;	645	my $perl = $^X;
469		646
470	# first we try $^X, but the path must be absolute (always on win32), and end in sth.	647	# first we try $^X, but the path must be absolute (always on win32), and end in sth.
471	# that looks like perl. this obviously only works for posix and win32	648	# that looks like perl. this obviously only works for posix and win32
472	unless (	649	unless (
473	($^O eq "MSWin32" \|\| $perl =~ m%^/%)	650	($^O eq "MSWin32" \|\| $perl =~ m%^/%)
474	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i	651	&& $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i
475	) {	652	) {
476	# if it doesn't look perlish enough, try Config	653	# if it doesn't look perlish enough, try Config
477	require Config;	654	require Config;
478	$perl = $Config::Config{perlpath};	655	$perl = $Config::Config{perlpath};
479	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;	656	$perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;
		657	}
		658
		659	$PERL = $perl;
480	}	660	}
481		661
482	require Proc::FastSpawn;	662	require Proc::FastSpawn;
483		663
484	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;	664	my ($fh, $slave) = AnyEvent::Util::portable_socketpair;
…		…
492	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;	672	#local $ENV{PERL5LIB} = join ":", grep !ref, @INC;
493	my %env = %ENV;	673	my %env = %ENV;
494	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;	674	$env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;
495		675
496	my $pid = Proc::FastSpawn::spawn (	676	my $pid = Proc::FastSpawn::spawn (
497	$perl,	677	$PERL,
498	["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],	678	[$PERL, "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],
499	[map "$_=$env{$_}", keys %env],	679	[map "$_=$env{$_}", keys %env],
500	) or die "unable to spawn AnyEvent::Fork server: $!";	680	) or die "unable to spawn AnyEvent::Fork server: $!";
501		681
502	$self->_new ($fh, $pid)	682	$self->_new ($fh, $pid)
503	}	683	}
504		684
505	=item $pid = $proc->pid	685	=item $pid = $proc->pid
506		686
507	Returns the process id of the process I<iff it is a direct child of the	687	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.	688	process running AnyEvent::Fork>, and C<undef> otherwise. As a general
		689	rule (that you cannot rely upon), processes created via C<new_exec>,
		690	L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template> are direct
		691	children, while all other processes are not.
509		692
510	Normally, only processes created via C<< AnyEvent::Fork->new_exec >> and	693	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	694	processes created via C<new>, but when in doubt, or zombies are a problem,
512	to clean up their zombies when they die.	695	you need to check whether a process is a diretc child by calling this
513		696	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		697
517	=cut	698	=cut
518		699
519	sub pid {	700	sub pid {
520	$_[0][0]	701	$_[0][PID]
521	}	702	}
522		703
523	=item $proc = $proc->eval ($perlcode, @args)	704	=item $proc = $proc->eval ($perlcode, @args)
524		705
525	Evaluates the given C<$perlcode> as ... perl code, while setting C<@_> to	706	Evaluates the given C<$perlcode> as ... Perl code, while setting C<@_> to
526	the strings specified by C<@args>, in the "main" package.	707	the strings specified by C<@args>, in the "main" package.
527		708
528	This call is meant to do any custom initialisation that might be required	709	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	710	(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.	711	to completely take over the process, use C<run> for that.
531		712
532	The code will usually be executed after this call returns, and there is no	713	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	714	way to pass anything back to the calling process. Any evaluation errors
534	will be reported to stderr and cause the process to exit.	715	will be reported to stderr and cause the process to exit.
535		716
536	If you want to execute some code to take over the process (see the	717	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	718	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	719	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.	720	C<send_xxx> methods, such as file handles. See the L<use AnyEvent::Fork as
		721	a faster fork+exec> example to see it in action.
540		722
541	Returns the process object for easy chaining of method calls.	723	Returns the process object for easy chaining of method calls.
		724
		725	It's common to want to call an iniitalisation function with some
		726	arguments. Make sure you actually pass C<@_> to that function (for example
		727	by using C<&name> syntax), and do not just specify a function name:
		728
		729	$proc->eval ('&MyModule::init', $string1, $string2);
542		730
543	=cut	731	=cut
544		732
545	sub eval {	733	sub eval {
546	my ($self, $code, @args) = @_;	734	my ($self, $code, @args) = @_;
…		…
570	=item $proc = $proc->send_fh ($handle, ...)	758	=item $proc = $proc->send_fh ($handle, ...)
571		759
572	Send one or more file handles (I<not> file descriptors) to the process,	760	Send one or more file handles (I<not> file descriptors) to the process,
573	to prepare a call to C<run>.	761	to prepare a call to C<run>.
574		762
575	The process object keeps a reference to the handles until this is done,	763	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	764	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	765	handles. This is most easily accomplished by simply not storing the file
578	them to this method.	766	handles anywhere after passing them to this method - when AnyEvent::Fork
		767	is finished using them, perl will automatically close them.
579		768
580	Returns the process object for easy chaining of method calls.	769	Returns the process object for easy chaining of method calls.
581		770
582	Example: pass a file handle to a process, and release it without	771	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.	772	closing. It will be closed automatically when it is no longer used.
…		…
590	sub send_fh {	779	sub send_fh {
591	my ($self, @fh) = @_;	780	my ($self, @fh) = @_;
592		781
593	for my $fh (@fh) {	782	for my $fh (@fh) {
594	$self->_cmd ("h");	783	$self->_cmd ("h");
595	push @{ $self->[2] }, \$fh;	784	push @{ $self->[QUEUE] }, \$fh;
596	}	785	}
597		786
598	$self	787	$self
599	}	788	}
600		789
601	=item $proc = $proc->send_arg ($string, ...)	790	=item $proc = $proc->send_arg ($string, ...)
602		791
603	Send one or more argument strings to the process, to prepare a call to	792	Send one or more argument strings to the process, to prepare a call to
604	C<run>. The strings can be any octet string.	793	C<run>. The strings can be any octet strings.
605		794
606	The protocol is optimised to pass a moderate number of relatively short	795	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	796	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	797	meant to pass some ID information or other startup info, not big chunks of
609	data.	798	data.
…		…
625	Enter the function specified by the function name in C<$func> in the	814	Enter the function specified by the function name in C<$func> in the
626	process. The function is called with the communication socket as first	815	process. The function is called with the communication socket as first
627	argument, followed by all file handles and string arguments sent earlier	816	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.	817	via C<send_fh> and C<send_arg> methods, in the order they were called.
629		818
		819	The process object becomes unusable on return from this function - any
		820	further method calls result in undefined behaviour.
		821
630	The function name should be fully qualified, but if it isn't, it will be	822	The function name should be fully qualified, but if it isn't, it will be
631	looked up in the main package.	823	looked up in the C<main> package.
632		824
633	If the called function returns, doesn't exist, or any error occurs, the	825	If the called function returns, doesn't exist, or any error occurs, the
634	process exits.	826	process exits.
635		827
636	Preparing the process is done in the background - when all commands have	828	Preparing the process is done in the background - when all commands have
637	been sent, the callback is invoked with the local communications socket	829	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	830	as argument. At this point you can start using the socket in any way you
639	like.	831	like.
640		832
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,	833	If the communication socket isn't used, it should be closed on both sides,
645	to save on kernel memory.	834	to save on kernel memory.
646		835
647	The socket is non-blocking in the parent, and blocking in the newly	836	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.	837	created process. The close-on-exec flag is set in both.
649		838
650	Even if not used otherwise, the socket can be a good indicator for the	839	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	840	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	841	event on it, because exiting the process closes the socket (if it didn't
653	create any children using fork).	842	create any children using fork).
		843
		844	=over 4
		845
		846	=item Compatibility to L<AnyEvent::Fork::Remote>
		847
		848	If you want to write code that works with both this module and
		849	L<AnyEvent::Fork::Remote>, you need to write your code so that it assumes
		850	there are two file handles for communications, which might not be unix
		851	domain sockets. The C<run> function should start like this:
		852
		853	sub run {
		854	my ($rfh, @args) = @_; # @args is your normal arguments
		855	my $wfh = fileno $rfh ? $rfh : *STDOUT;
		856
		857	# now use $rfh for reading and $wfh for writing
		858	}
		859
		860	This checks whether the passed file handle is, in fact, the process
		861	C<STDIN> handle. If it is, then the function was invoked visa
		862	L<AnyEvent::Fork::Remote>, so STDIN should be used for reading and
		863	C<STDOUT> should be used for writing.
		864
		865	In all other cases, the function was called via this module, and there is
		866	only one file handle that should be sued for reading and writing.
		867
		868	=back
654		869
655	Example: create a template for a process pool, pass a few strings, some	870	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.	871	file handles, then fork, pass one more string, and run some code.
657		872
658	my $pool = AnyEvent::Fork	873	my $pool = AnyEvent::Fork
…		…
686	=cut	901	=cut
687		902
688	sub run {	903	sub run {
689	my ($self, $func, $cb) = @_;	904	my ($self, $func, $cb) = @_;
690		905
691	$self->[4] = $cb;	906	$self->[CB] = $cb;
692	$self->_cmd (r => $func);	907	$self->_cmd (r => $func);
		908	}
		909
		910	=back
		911
		912	=head2 EXPERIMENTAL METHODS
		913
		914	These methods might go away completely or change behaviour, at any time.
		915
		916	=over 4
		917
		918	=item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED
		919
		920	Flushes all commands out to the process and then calls the callback with
		921	the communications socket.
		922
		923	The process object becomes unusable on return from this function - any
		924	further method calls result in undefined behaviour.
		925
		926	The point of this method is to give you a file handle that you can pass
		927	to another process. In that other process, you can call C<new_from_fh
		928	AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it,
		929	thereby effectively passing a fork object to another process.
		930
		931	=cut
		932
		933	sub to_fh {
		934	my ($self, $cb) = @_;
		935
		936	$self->[CB] = $cb;
		937
		938	unless ($self->[WW]) {
		939	$self->[CB]->($self->[FH]);
		940	@$self = ();
		941	}
		942	}
		943
		944	=item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED
		945
		946	Takes a file handle originally rceeived by the C<to_fh> method and creates
		947	a new C<AnyEvent:Fork> object. The child process itself will not change in
		948	any way, i.e. it will keep all the modifications done to it before calling
		949	C<to_fh>.
		950
		951	The new object is very much like the original object, except that the
		952	C<pid> method will return C<undef> even if the process is a direct child.
		953
		954	=cut
		955
		956	sub new_from_fh {
		957	my ($class, $fh) = @_;
		958
		959	$class->_new ($fh)
693	}	960	}
694		961
695	=back	962	=back
696		963
697	=head1 PERFORMANCE	964	=head1 PERFORMANCE
…		…
707		974
708	2079 new processes per second, using manual socketpair + fork	975	2079 new processes per second, using manual socketpair + fork
709		976
710	Then I did the same thing, but instead of calling fork, I called	977	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	978	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	979	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	980	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	981	(2440kB), and the socket needs to be passed to the server at the other end
715	of the socket first.	982	of the socket first.
716		983
717	2307 new processes per second, using AnyEvent::Fork->new	984	2307 new processes per second, using AnyEvent::Fork->new
…		…
722	479 vfork+execs per second, using AnyEvent::Fork->new_exec	989	479 vfork+execs per second, using AnyEvent::Fork->new_exec
723		990
724	So how can C<< AnyEvent->new >> be faster than a standard fork, even	991	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?	992	though it uses the same operations, but adds a lot of overhead?
726		993
727	The difference is simply the process size: forking the 6MB process takes	994	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	995	so much longer than forking the 2.5MB template process that the extra
729	introduced is canceled out.	996	overhead is canceled out.
730		997
731	If the benchmark process grows, the normal fork becomes even slower:	998	If the benchmark process grows, the normal fork becomes even slower:
732		999
733	1340 new processes, manual fork in a 20MB process	1000	1340 new processes, manual fork of a 20MB process
734	731 new processes, manual fork in a 200MB process	1001	731 new processes, manual fork of a 200MB process
735	235 new processes, manual fork in a 2000MB process	1002	235 new processes, manual fork of a 2000MB process
736		1003
737	What that means (to me) is that I can use this module without having a	1004	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	1005	conscience because of the extra overhead required to start new processes.
739	processes.
740		1006
741	=head1 TYPICAL PROBLEMS	1007	=head1 TYPICAL PROBLEMS
742		1008
743	This section lists typical problems that remain. I hope by recognising	1009	This section lists typical problems that remain. I hope by recognising
744	them, most can be avoided.	1010	them, most can be avoided.
745		1011
746	=over 4	1012	=over 4
747		1013
748	=item "leaked" file descriptors for exec'ed processes	1014	=item leaked file descriptors for exec'ed processes
749		1015
750	POSIX systems inherit file descriptors by default when exec'ing a new	1016	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	1017	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	1018	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.	1019	often not possible to set the flag in a race-free manner.
…		…
773	libraries or the code that leaks those file descriptors.	1039	libraries or the code that leaks those file descriptors.
774		1040
775	Fortunately, most of these leaked descriptors do no harm, other than	1041	Fortunately, most of these leaked descriptors do no harm, other than
776	sitting on some resources.	1042	sitting on some resources.
777		1043
778	=item "leaked" file descriptors for fork'ed processes	1044	=item leaked file descriptors for fork'ed processes
779		1045
780	Normally, L<AnyEvent::Fork> does start new processes by exec'ing them,	1046	Normally, L<AnyEvent::Fork> does start new processes by exec'ing them,
781	which closes file descriptors not marked for being inherited.	1047	which closes file descriptors not marked for being inherited.
782		1048
783	However, L<AnyEvent::Fork::Early> and L<AnyEvent::Fork::Template> offer	1049	However, L<AnyEvent::Fork::Early> and L<AnyEvent::Fork::Template> offer
…		…
792		1058
793	The solution is to either not load these modules before use'ing	1059	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	1060	L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template>, or to delay
795	initialising them, for example, by calling C<init Gtk2> manually.	1061	initialising them, for example, by calling C<init Gtk2> manually.
796		1062
797	=item exit runs destructors	1063	=item exiting calls object destructors
798		1064
799	This only applies to users of Lc<AnyEvent::Fork:Early> and	1065	This only applies to users of L<AnyEvent::Fork:Early> and
800	L<AnyEvent::Fork::Template>.	1066	L<AnyEvent::Fork::Template>, or when initialising code creates objects
		1067	that reference external resources.
801		1068
802	When a process created by AnyEvent::Fork exits, it might do so by calling	1069	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	1070	exit, or simply letting perl reach the end of the program. At which point
804	Perl runs all destructors.	1071	Perl runs all destructors.
805		1072
…		…
824	to make it so, mostly due to the bloody broken perl that nobody seems to	1091	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	1092	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	1093	useful that you can do with it without running into memory corruption
827	issues or other braindamage. Hrrrr.	1094	issues or other braindamage. Hrrrr.
828		1095
829	Cygwin perl is not supported at the moment, as it should implement fd	1096	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	1097	work within it's documented limits) and quite obviously it's not getting
831	support enough functionality to do it.	1098	improved any time soon, the best way to proceed on windows would be to
		1099	always use C<new_exec> and thus never rely on perl's fork "emulation".
		1100
		1101	Cygwin perl is not supported at the moment due to some hilarious
		1102	shortcomings of its API - see L<IO::FDPoll> for more details. If you never
		1103	use C<send_fh> and always use C<new_exec> to create processes, it should
		1104	work though.
		1105
		1106	=head1 USING AnyEvent::Fork IN SUBPROCESSES
		1107
		1108	AnyEvent::Fork itself cannot generally be used in subprocesses. As long as
		1109	only one process ever forks new processes, sharing the template processes
		1110	is possible (you could use a pipe as a lock by writing a byte into it to
		1111	unlock, and reading the byte to lock for example)
		1112
		1113	To make concurrent calls possible after fork, you should get rid of the
		1114	template and early fork processes. AnyEvent::Fork will create a new
		1115	template process as needed.
		1116
		1117	undef $AnyEvent::Fork::EARLY;
		1118	undef $AnyEvent::Fork::TEMPLATE;
		1119
		1120	It doesn't matter whether you get rid of them in the parent or child after
		1121	a fork.
832		1122
833	=head1 SEE ALSO	1123	=head1 SEE ALSO
834		1124
835	L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter),	1125	L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all
		1126	(part of this distribution).
		1127
836	L<AnyEvent::Fork::Template> (to create a process by forking the main	1128	L<AnyEvent::Fork::Template>, to create a process by forking the main
837	program at a convenient time).	1129	program at a convenient time (part of this distribution).
838		1130
839	=head1 AUTHOR	1131	L<AnyEvent::Fork::Remote>, for another way to create processes that is
		1132	mostly compatible to this module and modules building on top of it, but
		1133	works better with remote processes.
		1134
		1135	L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN).
		1136
		1137	L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN).
		1138
		1139	=head1 AUTHOR AND CONTACT INFORMATION
840		1140
841	Marc Lehmann <schmorp@schmorp.de>	1141	Marc Lehmann <schmorp@schmorp.de>
842	http://home.schmorp.de/	1142	http://software.schmorp.de/pkg/AnyEvent-Fork
843		1143
844	=cut	1144	=cut
845		1145
846	1	1146	1
847		1147

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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 1.67 by root, Thu May 12 16:54:01 2016 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 1.67 by root, Thu May 12 16:54:01 2016 UTC