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Revision 1.77 by root, Wed Oct 25 17:57:30 2006 UTC vs.
Revision 1.183 by root, Sun Sep 12 03:40:05 2010 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
30	# AnyEvent integration
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33
34	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',
37	cb => \&IO::AIO::poll_cb);
38
39	# Glib/Gtk2 integration
40	add_watch Glib::IO IO::AIO::poll_fileno,
41	in => sub { IO::AIO::poll_cb; 1 };
42
43	# Tk integration
44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
45	readable => \&IO::AIO::poll_cb);
46
47	# Danga::Socket integration
48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
49	\&IO::AIO::poll_cb);
50
51	=head1 DESCRIPTION	31	=head1 DESCRIPTION
52		32
53	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
54	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
		36
		37	Asynchronous means that operations that can normally block your program
		38	(e.g. reading from disk) will be done asynchronously: the operation
		39	will still block, but you can do something else in the meantime. This
		40	is extremely useful for programs that need to stay interactive even
		41	when doing heavy I/O (GUI programs, high performance network servers
		42	etc.), but can also be used to easily do operations in parallel that are
		43	normally done sequentially, e.g. stat'ing many files, which is much faster
		44	on a RAID volume or over NFS when you do a number of stat operations
		45	concurrently.
		46
		47	While most of this works on all types of file descriptors (for
		48	example sockets), using these functions on file descriptors that
		49	support nonblocking operation (again, sockets, pipes etc.) is
		50	very inefficient. Use an event loop for that (such as the L<EV>
		51	module): IO::AIO will naturally fit into such an event loop itself.
55		52
56	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
57	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
58	in perl, and the threads created by this module will not be visible	55	in perl, and the threads created by this module will not be visible
59	to perl. In the future, this module might make use of the native aio	56	to perl. In the future, this module might make use of the native aio
60	functions available on many operating systems. However, they are often	57	functions available on many operating systems. However, they are often
61	not well-supported or restricted (Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
63	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
64	using threads anyway.	61	using threads anyway.
65		62
66	Although the module will work with in the presence of other (Perl-)	63	Although the module will work in the presence of other (Perl-) threads,
67	threads, it is currently not reentrant in any way, so use appropriate	64	it is currently not reentrant in any way, so use appropriate locking
68	locking yourself, always call C<poll_cb> from within the same thread, or	65	yourself, always call C<poll_cb> from within the same thread, or never
69	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
		67
		68	=head2 EXAMPLE
		69
		70	This is a simple example that uses the EV module and loads
		71	F</etc/passwd> asynchronously:
		72
		73	use Fcntl;
		74	use EV;
		75	use IO::AIO;
		76
		77	# register the IO::AIO callback with EV
		78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		79
		80	# queue the request to open /etc/passwd
		81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
		82	my $fh = shift
		83	or die "error while opening: $!";
		84
		85	# stat'ing filehandles is generally non-blocking
		86	my $size = -s $fh;
		87
		88	# queue a request to read the file
		89	my $contents;
		90	aio_read $fh, 0, $size, $contents, 0, sub {
		91	$_[0] == $size
		92	or die "short read: $!";
		93
		94	close $fh;
		95
		96	# file contents now in $contents
		97	print $contents;
		98
		99	# exit event loop and program
		100	EV::unloop;
		101	};
		102	};
		103
		104	# possibly queue up other requests, or open GUI windows,
		105	# check for sockets etc. etc.
		106
		107	# process events as long as there are some:
		108	EV::loop;
70		109
71	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
72		111
73	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
74	directly visible to Perl.	113	directly visible to Perl.
…		…
116	Request has reached the end of its lifetime and holds no resources anymore	155	Request has reached the end of its lifetime and holds no resources anymore
117	(except possibly for the Perl object, but its connection to the actual	156	(except possibly for the Perl object, but its connection to the actual
118	aio request is severed and calling its methods will either do nothing or	157	aio request is severed and calling its methods will either do nothing or
119	result in a runtime error).	158	result in a runtime error).
120		159
		160	=back
		161
121	=cut	162	=cut
122		163
123	package IO::AIO;	164	package IO::AIO;
124		165
125	no warnings;	166	use Carp ();
126	use strict 'vars';	167
		168	use common::sense;
127		169
128	use base 'Exporter';	170	use base 'Exporter';
129		171
130	BEGIN {	172	BEGIN {
131	our $VERSION = '2.0';	173	our $VERSION = '3.65';
132		174
133	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
134	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
		178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		179	aio_rename aio_link aio_move aio_copy aio_group
		180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
136	aio_group aio_nop);	183	aio_statvfs);
		184
137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139	min_parallel max_parallel nreqs);	187	min_parallel max_parallel max_idle
		188	nreqs nready npending nthreads
		189	max_poll_time max_poll_reqs
		190	sendfile fadvise madvise
		191	mmap munmap munlock munlockall);
		192
		193	push @AIO_REQ, qw(aio_busy); # not exported
140		194
141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142		196
143	require XSLoader;	197	require XSLoader;
144	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
145	}	199	}
146		200
147	=head1 FUNCTIONS	201	=head1 FUNCTIONS
148		202
		203	=head2 QUICK OVERVIEW
		204
		205	This section simply lists the prototypes of the most important functions
		206	for quick reference. See the following sections for function-by-function
		207	documentation.
		208
		209	aio_open $pathname, $flags, $mode, $callback->($fh)
		210	aio_close $fh, $callback->($status)
		211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		214	aio_readahead $fh,$offset,$length, $callback->($retval)
		215	aio_stat $fh_or_path, $callback->($status)
		216	aio_lstat $fh, $callback->($status)
		217	aio_statvfs $fh_or_path, $callback->($statvfs)
		218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		220	aio_truncate $fh_or_path, $offset, $callback->($status)
		221	aio_chmod $fh_or_path, $mode, $callback->($status)
		222	aio_unlink $pathname, $callback->($status)
		223	aio_mknod $path, $mode, $dev, $callback->($status)
		224	aio_link $srcpath, $dstpath, $callback->($status)
		225	aio_symlink $srcpath, $dstpath, $callback->($status)
		226	aio_readlink $path, $callback->($link)
		227	aio_rename $srcpath, $dstpath, $callback->($status)
		228	aio_mkdir $pathname, $mode, $callback->($status)
		229	aio_rmdir $pathname, $callback->($status)
		230	aio_readdir $pathname, $callback->($entries)
		231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		234	aio_load $path, $data, $callback->($status)
		235	aio_copy $srcpath, $dstpath, $callback->($status)
		236	aio_move $srcpath, $dstpath, $callback->($status)
		237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		238	aio_rmtree $path, $callback->($status)
		239	aio_sync $callback->($status)
		240	aio_fsync $fh, $callback->($status)
		241	aio_fdatasync $fh, $callback->($status)
		242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		243	aio_pathsync $path, $callback->($status)
		244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		247	aio_mlockall $flags, $callback->($status)
		248	aio_group $callback->(...)
		249	aio_nop $callback->()
		250
		251	$prev_pri = aioreq_pri [$pri]
		252	aioreq_nice $pri_adjust
		253
		254	IO::AIO::poll_wait
		255	IO::AIO::poll_cb
		256	IO::AIO::poll
		257	IO::AIO::flush
		258	IO::AIO::max_poll_reqs $nreqs
		259	IO::AIO::max_poll_time $seconds
		260	IO::AIO::min_parallel $nthreads
		261	IO::AIO::max_parallel $nthreads
		262	IO::AIO::max_idle $nthreads
		263	IO::AIO::max_outstanding $maxreqs
		264	IO::AIO::nreqs
		265	IO::AIO::nready
		266	IO::AIO::npending
		267
		268	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		269	IO::AIO::fadvise $fh, $offset, $len, $advice
		270	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		271	IO::AIO::munlockall
		272
149	=head2 AIO FUNCTIONS	273	=head2 AIO REQUEST FUNCTIONS
150		274
151	All the C<aio_*> calls are more or less thin wrappers around the syscall	275	All the C<aio_*> calls are more or less thin wrappers around the syscall
152	with the same name (sans C<aio_>). The arguments are similar or identical,	276	with the same name (sans C<aio_>). The arguments are similar or identical,
153	and they all accept an additional (and optional) C<$callback> argument	277	and they all accept an additional (and optional) C<$callback> argument
154	which must be a code reference. This code reference will get called with	278	which must be a code reference. This code reference will get called with
155	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	279	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
156	perl, which usually delivers "false") as it's sole argument when the given	280	perl, which usually delivers "false") as its sole argument after the given
157	syscall has been executed asynchronously.	281	syscall has been executed asynchronously.
158		282
159	All functions expecting a filehandle keep a copy of the filehandle	283	All functions expecting a filehandle keep a copy of the filehandle
160	internally until the request has finished.	284	internally until the request has finished.
161		285
162	All requests return objects of type L<IO::AIO::REQ> that allow further	286	All functions return request objects of type L<IO::AIO::REQ> that allow
163	manipulation of those requests while they are in-flight.	287	further manipulation of those requests while they are in-flight.
164		288
165	The pathnames you pass to these routines I<must> be absolute and	289	The pathnames you pass to these routines I<must> be absolute and
166	encoded in byte form. The reason for the former is that at the time the	290	encoded as octets. The reason for the former is that at the time the
167	request is being executed, the current working directory could have	291	request is being executed, the current working directory could have
168	changed. Alternatively, you can make sure that you never change the	292	changed. Alternatively, you can make sure that you never change the
169	current working directory.	293	current working directory anywhere in the program and then use relative
		294	paths.
170		295
171	To encode pathnames to byte form, either make sure you either: a)	296	To encode pathnames as octets, either make sure you either: a) always pass
172	always pass in filenames you got from outside (command line, readdir	297	in filenames you got from outside (command line, readdir etc.) without
173	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	298	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174	your pathnames to the locale (or other) encoding in effect in the user	299	your pathnames to the locale (or other) encoding in effect in the user
175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	300	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176	use something else.	301	use something else to ensure your scalar has the correct contents.
		302
		303	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		304	handles correctly whether it is set or not.
177		305
178	=over 4	306	=over 4
179		307
180	=item aioreq_pri $pri	308	=item $prev_pri = aioreq_pri [$pri]
181		309
182	Sets the priority for the next aio request. The default priority	310	Returns the priority value that would be used for the next request and, if
		311	C<$pri> is given, sets the priority for the next aio request.
		312
183	is C<0>, the minimum and maximum priorities are C<-4> and C<4>,	313	The default priority is C<0>, the minimum and maximum priorities are C<-4>
184	respectively. Requests with higher priority will be serviced first.	314	and C<4>, respectively. Requests with higher priority will be serviced
		315	first.
185		316
186	The priority will be reset to C<0> after each call to one of the C<aio_>	317	The priority will be reset to C<0> after each call to one of the C<aio_*>
187	functions.	318	functions.
188		319
189	Example: open a file with low priority, then read something from it with	320	Example: open a file with low priority, then read something from it with
190	higher priority so the read request is serviced before other low priority	321	higher priority so the read request is serviced before other low priority
191	open requests (potentially spamming the cache):	322	open requests (potentially spamming the cache):
…		…
198	aio_read $_[0], ..., sub {	329	aio_read $_[0], ..., sub {
199	...	330	...
200	};	331	};
201	};	332	};
202		333
		334
203	=item aioreq_nice $pri_adjust	335	=item aioreq_nice $pri_adjust
204		336
205	Similar to C<aioreq_pri>, but subtracts the given value from the current	337	Similar to C<aioreq_pri>, but subtracts the given value from the current
206	priority, so effects are cumulative.	338	priority, so the effect is cumulative.
		339
207		340
208	=item aio_open $pathname, $flags, $mode, $callback->($fh)	341	=item aio_open $pathname, $flags, $mode, $callback->($fh)
209		342
210	Asynchronously open or create a file and call the callback with a newly	343	Asynchronously open or create a file and call the callback with a newly
211	created filehandle for the file.	344	created filehandle for the file.
…		…
217	list. They are the same as used by C<sysopen>.	350	list. They are the same as used by C<sysopen>.
218		351
219	Likewise, C<$mode> specifies the mode of the newly created file, if it	352	Likewise, C<$mode> specifies the mode of the newly created file, if it
220	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	353	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
221	except that it is mandatory (i.e. use C<0> if you don't create new files,	354	except that it is mandatory (i.e. use C<0> if you don't create new files,
222	and C<0666> or C<0777> if you do).	355	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		356	by the umask in effect then the request is being executed, so better never
		357	change the umask.
223		358
224	Example:	359	Example:
225		360
226	aio_open "/etc/passwd", O_RDONLY, 0, sub {	361	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
227	if ($_[0]) {	362	if ($_[0]) {
228	print "open successful, fh is $_[0]\n";	363	print "open successful, fh is $_[0]\n";
229	...	364	...
230	} else {	365	} else {
231	die "open failed: $!\n";	366	die "open failed: $!\n";
232	}	367	}
233	};	368	};
234		369
		370
235	=item aio_close $fh, $callback->($status)	371	=item aio_close $fh, $callback->($status)
236		372
237	Asynchronously close a file and call the callback with the result	373	Asynchronously close a file and call the callback with the result
238	code. I<WARNING:> although accepted, you should not pass in a perl	374	code.
239	filehandle here, as perl will likely close the file descriptor another
240	time when the filehandle is destroyed. Normally, you can safely call perls
241	C<close> or just let filehandles go out of scope.
242		375
243	This is supposed to be a bug in the API, so that might change. It's	376	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
244	therefore best to avoid this function.	377	closing the file descriptor associated with the filehandle itself.
		378
		379	Therefore, C<aio_close> will not close the filehandle - instead it will
		380	use dup2 to overwrite the file descriptor with the write-end of a pipe
		381	(the pipe fd will be created on demand and will be cached).
		382
		383	Or in other words: the file descriptor will be closed, but it will not be
		384	free for reuse until the perl filehandle is closed.
		385
		386	=cut
245		387
246	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	388	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
247		389
248	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	390	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
249		391
250	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	392	Reads or writes C<$length> bytes from or to the specified C<$fh> and
251	into the scalar given by C<data> and offset C<dataoffset> and calls the	393	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
252	callback without the actual number of bytes read (or -1 on error, just	394	and calls the callback without the actual number of bytes read (or -1 on
253	like the syscall).	395	error, just like the syscall).
		396
		397	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		398	offset plus the actual number of bytes read.
		399
		400	If C<$offset> is undefined, then the current file descriptor offset will
		401	be used (and updated), otherwise the file descriptor offset will not be
		402	changed by these calls.
		403
		404	If C<$length> is undefined in C<aio_write>, use the remaining length of
		405	C<$data>.
		406
		407	If C<$dataoffset> is less than zero, it will be counted from the end of
		408	C<$data>.
254		409
255	The C<$data> scalar I<MUST NOT> be modified in any way while the request	410	The C<$data> scalar I<MUST NOT> be modified in any way while the request
256	is outstanding. Modifying it can result in segfaults or WW3 (if the	411	is outstanding. Modifying it can result in segfaults or World War III (if
257	necessary/optional hardware is installed).	412	the necessary/optional hardware is installed).
258		413
259	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	414	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
260	offset C<0> within the scalar:	415	offset C<0> within the scalar:
261		416
262	aio_read $fh, 7, 15, $buffer, 0, sub {	417	aio_read $fh, 7, 15, $buffer, 0, sub {
263	$_[0] > 0 or die "read error: $!";	418	$_[0] > 0 or die "read error: $!";
264	print "read $_[0] bytes: <$buffer>\n";	419	print "read $_[0] bytes: <$buffer>\n";
265	};	420	};
266		421
267	=item aio_move $srcpath, $dstpath, $callback->($status)
268
269	Try to move the I<file> (directories not supported as either source or
270	destination) from C<$srcpath> to C<$dstpath> and call the callback with
271	the C<0> (error) or C<-1> ok.
272
273	This is a composite request that tries to rename(2) the file first. If
274	rename files with C<EXDEV>, it creates the destination file with mode 0200
275	and copies the contents of the source file into it using C<aio_sendfile>,
276	followed by restoring atime, mtime, access mode and uid/gid, in that
277	order, and unlinking the C<$srcpath>.
278
279	If an error occurs, the partial destination file will be unlinked, if
280	possible, except when setting atime, mtime, access mode and uid/gid, where
281	errors are being ignored.
282
283	=cut
284
285	sub aio_move($$$) {
286	my ($src, $dst, $cb) = @_;
287
288	my $grp = aio_group $cb;
289
290	add $grp aio_rename $src, $dst, sub {
291	if ($_[0] && $! == EXDEV) {
292	add $grp aio_open $src, O_RDONLY, 0, sub {
293	if (my $src_fh = $_[0]) {
294	my @stat = stat $src_fh;
295
296	add $grp aio_open $dst, O_WRONLY, 0200, sub {
297	if (my $dst_fh = $_[0]) {
298	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
299	close $src_fh;
300
301	if ($_[0] == $stat[7]) {
302	utime $stat[8], $stat[9], $dst;
303	chmod $stat[2] & 07777, $dst_fh;
304	chown $stat[4], $stat[5], $dst_fh;
305	close $dst_fh;
306
307	add $grp aio_unlink $src, sub {
308	$grp->result ($_[0]);
309	};
310	} else {
311	my $errno = $!;
312	add $grp aio_unlink $dst, sub {
313	$! = $errno;
314	$grp->result (-1);
315	};
316	}
317	};
318	} else {
319	$grp->result (-1);
320	}
321	},
322
323	} else {
324	$grp->result (-1);
325	}
326	};
327	} else {
328	$grp->result ($_[0]);
329	}
330	};
331
332	$grp
333	}
334		422
335	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	423	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
336		424
337	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	425	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
338	reading at byte offset C<$in_offset>, and starts writing at the current	426	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
340	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	428	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
341	other.	429	other.
342		430
343	This call tries to make use of a native C<sendfile> syscall to provide	431	This call tries to make use of a native C<sendfile> syscall to provide
344	zero-copy operation. For this to work, C<$out_fh> should refer to a	432	zero-copy operation. For this to work, C<$out_fh> should refer to a
345	socket, and C<$in_fh> should refer to mmap'able file.	433	socket, and C<$in_fh> should refer to an mmap'able file.
346		434
347	If the native sendfile call fails or is not implemented, it will be	435	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		436	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
348	emulated, so you can call C<aio_sendfile> on any type of filehandle	437	it will be emulated, so you can call C<aio_sendfile> on any type of
349	regardless of the limitations of the operating system.	438	filehandle regardless of the limitations of the operating system.
350		439
351	Please note, however, that C<aio_sendfile> can read more bytes from	440	Please note, however, that C<aio_sendfile> can read more bytes from
352	C<$in_fh> than are written, and there is no way to find out how many	441	C<$in_fh> than are written, and there is no way to find out how many
353	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	442	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
354	provides the number of bytes written to C<$out_fh>. Only if the result	443	provides the number of bytes written to C<$out_fh>. Only if the result
355	value equals C<$length> one can assume that C<$length> bytes have been	444	value equals C<$length> one can assume that C<$length> bytes have been
356	read.	445	read.
		446
357		447
358	=item aio_readahead $fh,$offset,$length, $callback->($retval)	448	=item aio_readahead $fh,$offset,$length, $callback->($retval)
359		449
360	C<aio_readahead> populates the page cache with data from a file so that	450	C<aio_readahead> populates the page cache with data from a file so that
361	subsequent reads from that file will not block on disk I/O. The C<$offset>	451	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
367	file. The current file offset of the file is left unchanged.	457	file. The current file offset of the file is left unchanged.
368		458
369	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	459	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
370	emulated by simply reading the data, which would have a similar effect.	460	emulated by simply reading the data, which would have a similar effect.
371		461
		462
372	=item aio_stat $fh_or_path, $callback->($status)	463	=item aio_stat $fh_or_path, $callback->($status)
373		464
374	=item aio_lstat $fh, $callback->($status)	465	=item aio_lstat $fh, $callback->($status)
375		466
376	Works like perl's C<stat> or C<lstat> in void context. The callback will	467	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
389	aio_stat "/etc/passwd", sub {	480	aio_stat "/etc/passwd", sub {
390	$_[0] and die "stat failed: $!";	481	$_[0] and die "stat failed: $!";
391	print "size is ", -s _, "\n";	482	print "size is ", -s _, "\n";
392	};	483	};
393		484
		485
		486	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		487
		488	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		489	whether a file handle or path was passed.
		490
		491	On success, the callback is passed a hash reference with the following
		492	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		493	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		494	is passed.
		495
		496	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		497	C<ST_NOSUID>.
		498
		499	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		500	their correct value when available, or to C<0> on systems that do
		501	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		502	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		503	C<ST_NODIRATIME> and C<ST_RELATIME>.
		504
		505	Example: stat C</wd> and dump out the data if successful.
		506
		507	aio_statvfs "/wd", sub {
		508	my $f = $_[0]
		509	or die "statvfs: $!";
		510
		511	use Data::Dumper;
		512	say Dumper $f;
		513	};
		514
		515	# result:
		516	{
		517	bsize => 1024,
		518	bfree => 4333064312,
		519	blocks => 10253828096,
		520	files => 2050765568,
		521	flag => 4096,
		522	favail => 2042092649,
		523	bavail => 4333064312,
		524	ffree => 2042092649,
		525	namemax => 255,
		526	frsize => 1024,
		527	fsid => 1810
		528	}
		529
		530
		531	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		532
		533	Works like perl's C<utime> function (including the special case of $atime
		534	and $mtime being undef). Fractional times are supported if the underlying
		535	syscalls support them.
		536
		537	When called with a pathname, uses utimes(2) if available, otherwise
		538	utime(2). If called on a file descriptor, uses futimes(2) if available,
		539	otherwise returns ENOSYS, so this is not portable.
		540
		541	Examples:
		542
		543	# set atime and mtime to current time (basically touch(1)):
		544	aio_utime "path", undef, undef;
		545	# set atime to current time and mtime to beginning of the epoch:
		546	aio_utime "path", time, undef; # undef==0
		547
		548
		549	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		550
		551	Works like perl's C<chown> function, except that C<undef> for either $uid
		552	or $gid is being interpreted as "do not change" (but -1 can also be used).
		553
		554	Examples:
		555
		556	# same as "chown root path" in the shell:
		557	aio_chown "path", 0, -1;
		558	# same as above:
		559	aio_chown "path", 0, undef;
		560
		561
		562	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		563
		564	Works like truncate(2) or ftruncate(2).
		565
		566
		567	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		568
		569	Works like perl's C<chmod> function.
		570
		571
394	=item aio_unlink $pathname, $callback->($status)	572	=item aio_unlink $pathname, $callback->($status)
395		573
396	Asynchronously unlink (delete) a file and call the callback with the	574	Asynchronously unlink (delete) a file and call the callback with the
397	result code.	575	result code.
398		576
		577
		578	=item aio_mknod $path, $mode, $dev, $callback->($status)
		579
		580	[EXPERIMENTAL]
		581
		582	Asynchronously create a device node (or fifo). See mknod(2).
		583
		584	The only (POSIX-) portable way of calling this function is:
		585
		586	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		587
		588
399	=item aio_link $srcpath, $dstpath, $callback->($status)	589	=item aio_link $srcpath, $dstpath, $callback->($status)
400		590
401	Asynchronously create a new link to the existing object at C<$srcpath> at	591	Asynchronously create a new link to the existing object at C<$srcpath> at
402	the path C<$dstpath> and call the callback with the result code.	592	the path C<$dstpath> and call the callback with the result code.
403		593
		594
404	=item aio_symlink $srcpath, $dstpath, $callback->($status)	595	=item aio_symlink $srcpath, $dstpath, $callback->($status)
405		596
406	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	597	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
407	the path C<$dstpath> and call the callback with the result code.	598	the path C<$dstpath> and call the callback with the result code.
408		599
		600
		601	=item aio_readlink $path, $callback->($link)
		602
		603	Asynchronously read the symlink specified by C<$path> and pass it to
		604	the callback. If an error occurs, nothing or undef gets passed to the
		605	callback.
		606
		607
409	=item aio_rename $srcpath, $dstpath, $callback->($status)	608	=item aio_rename $srcpath, $dstpath, $callback->($status)
410		609
411	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	610	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
412	rename(2) and call the callback with the result code.	611	rename(2) and call the callback with the result code.
413		612
		613
		614	=item aio_mkdir $pathname, $mode, $callback->($status)
		615
		616	Asynchronously mkdir (create) a directory and call the callback with
		617	the result code. C<$mode> will be modified by the umask at the time the
		618	request is executed, so do not change your umask.
		619
		620
414	=item aio_rmdir $pathname, $callback->($status)	621	=item aio_rmdir $pathname, $callback->($status)
415		622
416	Asynchronously rmdir (delete) a directory and call the callback with the	623	Asynchronously rmdir (delete) a directory and call the callback with the
417	result code.	624	result code.
		625
418		626
419	=item aio_readdir $pathname, $callback->($entries)	627	=item aio_readdir $pathname, $callback->($entries)
420		628
421	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	629	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
422	directory (i.e. opendir + readdir + closedir). The entries will not be	630	directory (i.e. opendir + readdir + closedir). The entries will not be
423	sorted, and will B<NOT> include the C<.> and C<..> entries.	631	sorted, and will B<NOT> include the C<.> and C<..> entries.
424		632
425	The callback a single argument which is either C<undef> or an array-ref	633	The callback is passed a single argument which is either C<undef> or an
426	with the filenames.	634	array-ref with the filenames.
		635
		636
		637	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		638
		639	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		640	behaviour and output format. In case of an error, C<$entries> will be
		641	C<undef>.
		642
		643	The flags are a combination of the following constants, ORed together (the
		644	flags will also be passed to the callback, possibly modified):
		645
		646	=over 4
		647
		648	=item IO::AIO::READDIR_DENTS
		649
		650	When this flag is off, then the callback gets an arrayref with of names
		651	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		652	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		653	entry in more detail.
		654
		655	C<$name> is the name of the entry.
		656
		657	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		658
		659	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		660	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		661	C<IO::AIO::DT_WHT>.
		662
		663	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		664	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		665	scalars are read-only: you can not modify them.
		666
		667	C<$inode> is the inode number (which might not be exact on systems with 64
		668	bit inode numbers and 32 bit perls). This field has unspecified content on
		669	systems that do not deliver the inode information.
		670
		671	=item IO::AIO::READDIR_DIRS_FIRST
		672
		673	When this flag is set, then the names will be returned in an order where
		674	likely directories come first. This is useful when you need to quickly
		675	find directories, or you want to find all directories while avoiding to
		676	stat() each entry.
		677
		678	If the system returns type information in readdir, then this is used
		679	to find directories directly. Otherwise, likely directories are files
		680	beginning with ".", or otherwise files with no dots, of which files with
		681	short names are tried first.
		682
		683	=item IO::AIO::READDIR_STAT_ORDER
		684
		685	When this flag is set, then the names will be returned in an order
		686	suitable for stat()'ing each one. That is, when you plan to stat()
		687	all files in the given directory, then the returned order will likely
		688	be fastest.
		689
		690	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		691	the likely dirs come first, resulting in a less optimal stat order.
		692
		693	=item IO::AIO::READDIR_FOUND_UNKNOWN
		694
		695	This flag should not be set when calling C<aio_readdirx>. Instead, it
		696	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		697	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		698	C<$type>'s are known, which can be used to speed up some algorithms.
		699
		700	=back
		701
		702
		703	=item aio_load $path, $data, $callback->($status)
		704
		705	This is a composite request that tries to fully load the given file into
		706	memory. Status is the same as with aio_read.
		707
		708	=cut
		709
		710	sub aio_load($$;$) {
		711	my ($path, undef, $cb) = @_;
		712	my $data = \$_[1];
		713
		714	my $pri = aioreq_pri;
		715	my $grp = aio_group $cb;
		716
		717	aioreq_pri $pri;
		718	add $grp aio_open $path, O_RDONLY, 0, sub {
		719	my $fh = shift
		720	or return $grp->result (-1);
		721
		722	aioreq_pri $pri;
		723	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		724	$grp->result ($_[0]);
		725	};
		726	};
		727
		728	$grp
		729	}
		730
		731	=item aio_copy $srcpath, $dstpath, $callback->($status)
		732
		733	Try to copy the I<file> (directories not supported as either source or
		734	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		735	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		736
		737	This is a composite request that creates the destination file with
		738	mode 0200 and copies the contents of the source file into it using
		739	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		740	uid/gid, in that order.
		741
		742	If an error occurs, the partial destination file will be unlinked, if
		743	possible, except when setting atime, mtime, access mode and uid/gid, where
		744	errors are being ignored.
		745
		746	=cut
		747
		748	sub aio_copy($$;$) {
		749	my ($src, $dst, $cb) = @_;
		750
		751	my $pri = aioreq_pri;
		752	my $grp = aio_group $cb;
		753
		754	aioreq_pri $pri;
		755	add $grp aio_open $src, O_RDONLY, 0, sub {
		756	if (my $src_fh = $_[0]) {
		757	my @stat = stat $src_fh; # hmm, might block over nfs?
		758
		759	aioreq_pri $pri;
		760	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
		761	if (my $dst_fh = $_[0]) {
		762	aioreq_pri $pri;
		763	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		764	if ($_[0] == $stat[7]) {
		765	$grp->result (0);
		766	close $src_fh;
		767
		768	my $ch = sub {
		769	aioreq_pri $pri;
		770	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		771	aioreq_pri $pri;
		772	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		773	aioreq_pri $pri;
		774	add $grp aio_close $dst_fh;
		775	}
		776	};
		777	};
		778
		779	aioreq_pri $pri;
		780	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		781	if ($_[0] < 0 && $! == ENOSYS) {
		782	aioreq_pri $pri;
		783	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		784	} else {
		785	$ch->();
		786	}
		787	};
		788	} else {
		789	$grp->result (-1);
		790	close $src_fh;
		791	close $dst_fh;
		792
		793	aioreq $pri;
		794	add $grp aio_unlink $dst;
		795	}
		796	};
		797	} else {
		798	$grp->result (-1);
		799	}
		800	},
		801
		802	} else {
		803	$grp->result (-1);
		804	}
		805	};
		806
		807	$grp
		808	}
		809
		810	=item aio_move $srcpath, $dstpath, $callback->($status)
		811
		812	Try to move the I<file> (directories not supported as either source or
		813	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		814	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		815
		816	This is a composite request that tries to rename(2) the file first; if
		817	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
		818	that is successful, unlinks the C<$srcpath>.
		819
		820	=cut
		821
		822	sub aio_move($$;$) {
		823	my ($src, $dst, $cb) = @_;
		824
		825	my $pri = aioreq_pri;
		826	my $grp = aio_group $cb;
		827
		828	aioreq_pri $pri;
		829	add $grp aio_rename $src, $dst, sub {
		830	if ($_[0] && $! == EXDEV) {
		831	aioreq_pri $pri;
		832	add $grp aio_copy $src, $dst, sub {
		833	$grp->result ($_[0]);
		834
		835	if (!$_[0]) {
		836	aioreq_pri $pri;
		837	add $grp aio_unlink $src;
		838	}
		839	};
		840	} else {
		841	$grp->result ($_[0]);
		842	}
		843	};
		844
		845	$grp
		846	}
427		847
428	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	848	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
429		849
430	Scans a directory (similar to C<aio_readdir>) but additionally tries to	850	Scans a directory (similar to C<aio_readdir>) but additionally tries to
431	efficiently separate the entries of directory C<$path> into two sets of	851	efficiently separate the entries of directory C<$path> into two sets of
…		…
433	recurse into (everything else, including symlinks to directories).	853	recurse into (everything else, including symlinks to directories).
434		854
435	C<aio_scandir> is a composite request that creates of many sub requests_	855	C<aio_scandir> is a composite request that creates of many sub requests_
436	C<$maxreq> specifies the maximum number of outstanding aio requests that	856	C<$maxreq> specifies the maximum number of outstanding aio requests that
437	this function generates. If it is C<< <= 0 >>, then a suitable default	857	this function generates. If it is C<< <= 0 >>, then a suitable default
438	will be chosen (currently 6).	858	will be chosen (currently 4).
439		859
440	On error, the callback is called without arguments, otherwise it receives	860	On error, the callback is called without arguments, otherwise it receives
441	two array-refs with path-relative entry names.	861	two array-refs with path-relative entry names.
442		862
443	Example:	863	Example:
…		…
450		870
451	Implementation notes.	871	Implementation notes.
452		872
453	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	873	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
454		874
		875	If readdir returns file type information, then this is used directly to
		876	find directories.
		877
455	After reading the directory, the modification time, size etc. of the	878	Otherwise, after reading the directory, the modification time, size etc.
456	directory before and after the readdir is checked, and if they match (and	879	of the directory before and after the readdir is checked, and if they
457	isn't the current time), the link count will be used to decide how many	880	match (and isn't the current time), the link count will be used to decide
458	entries are directories (if >= 2). Otherwise, no knowledge of the number	881	how many entries are directories (if >= 2). Otherwise, no knowledge of the
459	of subdirectories will be assumed.	882	number of subdirectories will be assumed.
460		883
461	Then entries will be sorted into likely directories (everything without	884	Then entries will be sorted into likely directories a non-initial dot
462	a non-initial dot currently) and likely non-directories (everything	885	currently) and likely non-directories (see C<aio_readdirx>). Then every
463	else). Then every entry plus an appended C</.> will be C<stat>'ed,	886	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
464	likely directories first. If that succeeds, it assumes that the entry	887	in order of their inode numbers. If that succeeds, it assumes that the
465	is a directory or a symlink to directory (which will be checked	888	entry is a directory or a symlink to directory (which will be checked
466	seperately). This is often faster than stat'ing the entry itself because	889	seperately). This is often faster than stat'ing the entry itself because
467	filesystems might detect the type of the entry without reading the inode	890	filesystems might detect the type of the entry without reading the inode
468	data (e.g. ext2fs filetype feature).	891	data (e.g. ext2fs filetype feature), even on systems that cannot return
		892	the filetype information on readdir.
469		893
470	If the known number of directories (link count - 2) has been reached, the	894	If the known number of directories (link count - 2) has been reached, the
471	rest of the entries is assumed to be non-directories.	895	rest of the entries is assumed to be non-directories.
472		896
473	This only works with certainty on POSIX (= UNIX) filesystems, which	897	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
477	as those tend to return 0 or 1 as link counts, which disables the	901	as those tend to return 0 or 1 as link counts, which disables the
478	directory counting heuristic.	902	directory counting heuristic.
479		903
480	=cut	904	=cut
481		905
482	sub aio_scandir($$$) {	906	sub aio_scandir($$;$) {
483	my ($path, $maxreq, $cb) = @_;	907	my ($path, $maxreq, $cb) = @_;
484		908
		909	my $pri = aioreq_pri;
		910
485	my $grp = aio_group $cb;	911	my $grp = aio_group $cb;
486		912
487	$maxreq = 6 if $maxreq <= 0;	913	$maxreq = 4 if $maxreq <= 0;
488		914
489	# stat once	915	# stat once
		916	aioreq_pri $pri;
490	add $grp aio_stat $path, sub {	917	add $grp aio_stat $path, sub {
491	return $grp->result () if $_[0];	918	return $grp->result () if $_[0];
492	my $now = time;	919	my $now = time;
493	my $hash1 = join ":", (stat _)[0,1,3,7,9];	920	my $hash1 = join ":", (stat _)[0,1,3,7,9];
494		921
495	# read the directory entries	922	# read the directory entries
		923	aioreq_pri $pri;
496	add $grp aio_readdir $path, sub {	924	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
497	my $entries = shift	925	my $entries = shift
498	or return $grp->result ();	926	or return $grp->result ();
499		927
500	# stat the dir another time	928	# stat the dir another time
		929	aioreq_pri $pri;
501	add $grp aio_stat $path, sub {	930	add $grp aio_stat $path, sub {
502	my $hash2 = join ":", (stat _)[0,1,3,7,9];	931	my $hash2 = join ":", (stat _)[0,1,3,7,9];
503		932
504	my $ndirs;	933	my $ndirs;
505		934
506	# take the slow route if anything looks fishy	935	# take the slow route if anything looks fishy
507	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	936	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
508	$ndirs = -1;	937	$ndirs = -1;
509	} else {	938	} else {
510	# if nlink == 2, we are finished	939	# if nlink == 2, we are finished
511	# on non-posix-fs's, we rely on nlink < 2	940	# for non-posix-fs's, we rely on nlink < 2
512	$ndirs = (stat _)[3] - 2	941	$ndirs = (stat _)[3] - 2
513	or return $grp->result ([], $entries);	942	or return $grp->result ([], $entries);
514	}	943	}
515		944
516	# sort into likely dirs and likely nondirs
517	# dirs == files without ".", short entries first
518	$entries = [map $_->[0],
519	sort { $b->[1] cmp $a->[1] }
520	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
521	@$entries];
522
523	my (@dirs, @nondirs);	945	my (@dirs, @nondirs);
524		946
525	my $statgrp = add $grp aio_group sub {	947	my $statgrp = add $grp aio_group sub {
526	$grp->result (\@dirs, \@nondirs);	948	$grp->result (\@dirs, \@nondirs);
527	};	949	};
528		950
529	limit $statgrp $maxreq;	951	limit $statgrp $maxreq;
530	feed $statgrp sub {	952	feed $statgrp sub {
531	return unless @$entries;	953	return unless @$entries;
532	my $entry = pop @$entries;	954	my $entry = shift @$entries;
533		955
		956	aioreq_pri $pri;
534	add $statgrp aio_stat "$path/$entry/.", sub {	957	add $statgrp aio_stat "$path/$entry/.", sub {
535	if ($_[0] < 0) {	958	if ($_[0] < 0) {
536	push @nondirs, $entry;	959	push @nondirs, $entry;
537	} else {	960	} else {
538	# need to check for real directory	961	# need to check for real directory
		962	aioreq_pri $pri;
539	add $statgrp aio_lstat "$path/$entry", sub {	963	add $statgrp aio_lstat "$path/$entry", sub {
540	if (-d _) {	964	if (-d _) {
541	push @dirs, $entry;	965	push @dirs, $entry;
542		966
543	unless (--$ndirs) {	967	unless (--$ndirs) {
…		…
556	};	980	};
557		981
558	$grp	982	$grp
559	}	983	}
560		984
		985	=item aio_rmtree $path, $callback->($status)
		986
		987	Delete a directory tree starting (and including) C<$path>, return the
		988	status of the final C<rmdir> only. This is a composite request that
		989	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		990	everything else.
		991
		992	=cut
		993
		994	sub aio_rmtree;
		995	sub aio_rmtree($;$) {
		996	my ($path, $cb) = @_;
		997
		998	my $pri = aioreq_pri;
		999	my $grp = aio_group $cb;
		1000
		1001	aioreq_pri $pri;
		1002	add $grp aio_scandir $path, 0, sub {
		1003	my ($dirs, $nondirs) = @_;
		1004
		1005	my $dirgrp = aio_group sub {
		1006	add $grp aio_rmdir $path, sub {
		1007	$grp->result ($_[0]);
		1008	};
		1009	};
		1010
		1011	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1012	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1013
		1014	add $grp $dirgrp;
		1015	};
		1016
		1017	$grp
		1018	}
		1019
		1020	=item aio_sync $callback->($status)
		1021
		1022	Asynchronously call sync and call the callback when finished.
		1023
561	=item aio_fsync $fh, $callback->($status)	1024	=item aio_fsync $fh, $callback->($status)
562		1025
563	Asynchronously call fsync on the given filehandle and call the callback	1026	Asynchronously call fsync on the given filehandle and call the callback
564	with the fsync result code.	1027	with the fsync result code.
565		1028
…		…
568	Asynchronously call fdatasync on the given filehandle and call the	1031	Asynchronously call fdatasync on the given filehandle and call the
569	callback with the fdatasync result code.	1032	callback with the fdatasync result code.
570		1033
571	If this call isn't available because your OS lacks it or it couldn't be	1034	If this call isn't available because your OS lacks it or it couldn't be
572	detected, it will be emulated by calling C<fsync> instead.	1035	detected, it will be emulated by calling C<fsync> instead.
		1036
		1037	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1038
		1039	Sync the data portion of the file specified by C<$offset> and C<$length>
		1040	to disk (but NOT the metadata), by calling the Linux-specific
		1041	sync_file_range call. If sync_file_range is not available or it returns
		1042	ENOSYS, then fdatasync or fsync is being substituted.
		1043
		1044	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1045	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1046	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1047	manpage for details.
		1048
		1049	=item aio_pathsync $path, $callback->($status)
		1050
		1051	This request tries to open, fsync and close the given path. This is a
		1052	composite request intended to sync directories after directory operations
		1053	(E.g. rename). This might not work on all operating systems or have any
		1054	specific effect, but usually it makes sure that directory changes get
		1055	written to disc. It works for anything that can be opened for read-only,
		1056	not just directories.
		1057
		1058	Future versions of this function might fall back to other methods when
		1059	C<fsync> on the directory fails (such as calling C<sync>).
		1060
		1061	Passes C<0> when everything went ok, and C<-1> on error.
		1062
		1063	=cut
		1064
		1065	sub aio_pathsync($;$) {
		1066	my ($path, $cb) = @_;
		1067
		1068	my $pri = aioreq_pri;
		1069	my $grp = aio_group $cb;
		1070
		1071	aioreq_pri $pri;
		1072	add $grp aio_open $path, O_RDONLY, 0, sub {
		1073	my ($fh) = @_;
		1074	if ($fh) {
		1075	aioreq_pri $pri;
		1076	add $grp aio_fsync $fh, sub {
		1077	$grp->result ($_[0]);
		1078
		1079	aioreq_pri $pri;
		1080	add $grp aio_close $fh;
		1081	};
		1082	} else {
		1083	$grp->result (-1);
		1084	}
		1085	};
		1086
		1087	$grp
		1088	}
		1089
		1090	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1091
		1092	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1093	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1094	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1095	scalar must only be modified in-place while an aio operation is pending on
		1096	it).
		1097
		1098	It calls the C<msync> function of your OS, if available, with the memory
		1099	area starting at C<$offset> in the string and ending C<$length> bytes
		1100	later. If C<$length> is negative, counts from the end, and if C<$length>
		1101	is C<undef>, then it goes till the end of the string. The flags can be
		1102	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1103	C<IO::AIO::MS_SYNC>.
		1104
		1105	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1106
		1107	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1108	scalars.
		1109
		1110	It touches (reads or writes) all memory pages in the specified
		1111	range inside the scalar. All caveats and parameters are the same
		1112	as for C<aio_msync>, above, except for flags, which must be either
		1113	C<0> (which reads all pages and ensures they are instantiated) or
		1114	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1115	writing an octet from it, which dirties the page).
		1116
		1117	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1118
		1119	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1120	scalars.
		1121
		1122	It reads in all the pages of the underlying storage into memory (if any)
		1123	and locks them, so they are not getting swapped/paged out or removed.
		1124
		1125	If C<$length> is undefined, then the scalar will be locked till the end.
		1126
		1127	On systems that do not implement C<mlock>, this function returns C<-1>
		1128	and sets errno to C<ENOSYS>.
		1129
		1130	Note that the corresponding C<munlock> is synchronous and is
		1131	documented under L<MISCELLANEOUS FUNCTIONS>.
		1132
		1133	Example: open a file, mmap and mlock it - both will be undone when
		1134	C<$data> gets destroyed.
		1135
		1136	open my $fh, "<", $path or die "$path: $!";
		1137	my $data;
		1138	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1139	aio_mlock $data; # mlock in background
		1140
		1141	=item aio_mlockall $flags, $callback->($status)
		1142
		1143	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1144	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1145
		1146	On systems that do not implement C<mlockall>, this function returns C<-1>
		1147	and sets errno to C<ENOSYS>.
		1148
		1149	Note that the corresponding C<munlockall> is synchronous and is
		1150	documented under L<MISCELLANEOUS FUNCTIONS>.
		1151
		1152	Example: asynchronously lock all current and future pages into memory.
		1153
		1154	aio_mlockall IO::AIO::MCL_FUTURE;
573		1155
574	=item aio_group $callback->(...)	1156	=item aio_group $callback->(...)
575		1157
576	This is a very special aio request: Instead of doing something, it is a	1158	This is a very special aio request: Instead of doing something, it is a
577	container for other aio requests, which is useful if you want to bundle	1159	container for other aio requests, which is useful if you want to bundle
…		…
627	=item cancel $req	1209	=item cancel $req
628		1210
629	Cancels the request, if possible. Has the effect of skipping execution	1211	Cancels the request, if possible. Has the effect of skipping execution
630	when entering the B<execute> state and skipping calling the callback when	1212	when entering the B<execute> state and skipping calling the callback when
631	entering the the B<result> state, but will leave the request otherwise	1213	entering the the B<result> state, but will leave the request otherwise
632	untouched. That means that requests that currently execute will not be	1214	untouched (with the exception of readdir). That means that requests that
633	stopped and resources held by the request will not be freed prematurely.	1215	currently execute will not be stopped and resources held by the request
		1216	will not be freed prematurely.
634		1217
635	=item cb $req $callback->(...)	1218	=item cb $req $callback->(...)
636		1219
637	Replace (or simply set) the callback registered to the request.	1220	Replace (or simply set) the callback registered to the request.
638		1221
…		…
689	Their lifetime, simplified, looks like this: when they are empty, they	1272	Their lifetime, simplified, looks like this: when they are empty, they
690	will finish very quickly. If they contain only requests that are in the	1273	will finish very quickly. If they contain only requests that are in the
691	C<done> state, they will also finish. Otherwise they will continue to	1274	C<done> state, they will also finish. Otherwise they will continue to
692	exist.	1275	exist.
693		1276
694	That means after creating a group you have some time to add requests. And	1277	That means after creating a group you have some time to add requests
695	in the callbacks of those requests, you can add further requests to the	1278	(precisely before the callback has been invoked, which is only done within
696	group. And only when all those requests have finished will the the group	1279	the C<poll_cb>). And in the callbacks of those requests, you can add
697	itself finish.	1280	further requests to the group. And only when all those requests have
		1281	finished will the the group itself finish.
698		1282
699	=over 4	1283	=over 4
700		1284
701	=item add $grp ...	1285	=item add $grp ...
702		1286
…		…
711	=item $grp->cancel_subs	1295	=item $grp->cancel_subs
712		1296
713	Cancel all subrequests and clears any feeder, but not the group request	1297	Cancel all subrequests and clears any feeder, but not the group request
714	itself. Useful when you queued a lot of events but got a result early.	1298	itself. Useful when you queued a lot of events but got a result early.
715		1299
		1300	The group request will finish normally (you cannot add requests to the
		1301	group).
		1302
716	=item $grp->result (...)	1303	=item $grp->result (...)
717		1304
718	Set the result value(s) that will be passed to the group callback when all	1305	Set the result value(s) that will be passed to the group callback when all
719	subrequests have finished. By default, no argument will be passed.	1306	subrequests have finished and set the groups errno to the current value
		1307	of errno (just like calling C<errno> without an error number). By default,
		1308	no argument will be passed and errno is zero.
		1309
		1310	=item $grp->errno ([$errno])
		1311
		1312	Sets the group errno value to C<$errno>, or the current value of errno
		1313	when the argument is missing.
		1314
		1315	Every aio request has an associated errno value that is restored when
		1316	the callback is invoked. This method lets you change this value from its
		1317	default (0).
		1318
		1319	Calling C<result> will also set errno, so make sure you either set C<$!>
		1320	before the call to C<result>, or call c<errno> after it.
720		1321
721	=item feed $grp $callback->($grp)	1322	=item feed $grp $callback->($grp)
722		1323
723	Sets a feeder/generator on this group: every group can have an attached	1324	Sets a feeder/generator on this group: every group can have an attached
724	generator that generates requests if idle. The idea behind this is that,	1325	generator that generates requests if idle. The idea behind this is that,
725	although you could just queue as many requests as you want in a group,	1326	although you could just queue as many requests as you want in a group,
726	this might starve other requests for a potentially long time. For	1327	this might starve other requests for a potentially long time. For example,
727	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1328	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
728	requests, delaying any later requests for a long time.	1329	delaying any later requests for a long time.
729		1330
730	To avoid this, and allow incremental generation of requests, you can	1331	To avoid this, and allow incremental generation of requests, you can
731	instead a group and set a feeder on it that generates those requests. The	1332	instead a group and set a feeder on it that generates those requests. The
732	feed callback will be called whenever there are few enough (see C<limit>,	1333	feed callback will be called whenever there are few enough (see C<limit>,
733	below) requests active in the group itself and is expected to queue more	1334	below) requests active in the group itself and is expected to queue more
…		…
737	not impose any limits).	1338	not impose any limits).
738		1339
739	If the feed does not queue more requests when called, it will be	1340	If the feed does not queue more requests when called, it will be
740	automatically removed from the group.	1341	automatically removed from the group.
741		1342
742	If the feed limit is C<0>, it will be set to C<2> automatically.	1343	If the feed limit is C<0> when this method is called, it will be set to
		1344	C<2> automatically.
743		1345
744	Example:	1346	Example:
745		1347
746	# stat all files in @files, but only ever use four aio requests concurrently:	1348	# stat all files in @files, but only ever use four aio requests concurrently:
747		1349
…		…
759	Sets the feeder limit for the group: The feeder will be called whenever	1361	Sets the feeder limit for the group: The feeder will be called whenever
760	the group contains less than this many requests.	1362	the group contains less than this many requests.
761		1363
762	Setting the limit to C<0> will pause the feeding process.	1364	Setting the limit to C<0> will pause the feeding process.
763		1365
		1366	The default value for the limit is C<0>, but note that setting a feeder
		1367	automatically bumps it up to C<2>.
		1368
764	=back	1369	=back
765		1370
766	=head2 SUPPORT FUNCTIONS	1371	=head2 SUPPORT FUNCTIONS
767		1372
		1373	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		1374
768	=over 4	1375	=over 4
769		1376
770	=item $fileno = IO::AIO::poll_fileno	1377	=item $fileno = IO::AIO::poll_fileno
771		1378
772	Return the I<request result pipe file descriptor>. This filehandle must be	1379	Return the I<request result pipe file descriptor>. This filehandle must be
773	polled for reading by some mechanism outside this module (e.g. Event or	1380	polled for reading by some mechanism outside this module (e.g. EV, Glib,
774	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1381	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
775	to call C<poll_cb> to check the results.	1382	you have to call C<poll_cb> to check the results.
776		1383
777	See C<poll_cb> for an example.	1384	See C<poll_cb> for an example.
778		1385
779	=item IO::AIO::poll_cb	1386	=item IO::AIO::poll_cb
780		1387
781	Process all outstanding events on the result pipe. You have to call this	1388	Process some outstanding events on the result pipe. You have to call this
782	regularly. Returns the number of events processed. Returns immediately	1389	regularly. Returns C<0> if all events could be processed, or C<-1> if it
783	when no events are outstanding.	1390	returned earlier for whatever reason. Returns immediately when no events
		1391	are outstanding. The amount of events processed depends on the settings of
		1392	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
		1393
		1394	If not all requests were processed for whatever reason, the filehandle
		1395	will still be ready when C<poll_cb> returns, so normally you don't have to
		1396	do anything special to have it called later.
784		1397
785	Example: Install an Event watcher that automatically calls	1398	Example: Install an Event watcher that automatically calls
786	IO::AIO::poll_cb with high priority:	1399	IO::AIO::poll_cb with high priority (more examples can be found in the
		1400	SYNOPSIS section, at the top of this document):
787		1401
788	Event->io (fd => IO::AIO::poll_fileno,	1402	Event->io (fd => IO::AIO::poll_fileno,
789	poll => 'r', async => 1,	1403	poll => 'r', async => 1,
790	cb => \&IO::AIO::poll_cb);	1404	cb => \&IO::AIO::poll_cb);
791		1405
792	=item IO::AIO::poll_wait	1406	=item IO::AIO::poll_wait
793		1407
		1408	If there are any outstanding requests and none of them in the result
794	Wait till the result filehandle becomes ready for reading (simply does a	1409	phase, wait till the result filehandle becomes ready for reading (simply
795	C<select> on the filehandle. This is useful if you want to synchronously wait	1410	does a C<select> on the filehandle. This is useful if you want to
796	for some requests to finish).	1411	synchronously wait for some requests to finish).
797		1412
798	See C<nreqs> for an example.	1413	See C<nreqs> for an example.
799		1414
		1415	=item IO::AIO::poll
		1416
		1417	Waits until some requests have been handled.
		1418
		1419	Returns the number of requests processed, but is otherwise strictly
		1420	equivalent to:
		1421
		1422	IO::AIO::poll_wait, IO::AIO::poll_cb
		1423
800	=item IO::AIO::nreqs	1424	=item IO::AIO::flush
801		1425
802	Returns the number of requests currently outstanding (i.e. for which their	1426	Wait till all outstanding AIO requests have been handled.
803	callback has not been invoked yet).
804		1427
805	Example: wait till there are no outstanding requests anymore:	1428	Strictly equivalent to:
806		1429
807	IO::AIO::poll_wait, IO::AIO::poll_cb	1430	IO::AIO::poll_wait, IO::AIO::poll_cb
808	while IO::AIO::nreqs;	1431	while IO::AIO::nreqs;
809		1432
810	=item IO::AIO::flush	1433	=item IO::AIO::max_poll_reqs $nreqs
811		1434
812	Wait till all outstanding AIO requests have been handled.	1435	=item IO::AIO::max_poll_time $seconds
813		1436
814	Strictly equivalent to:	1437	These set the maximum number of requests (default C<0>, meaning infinity)
		1438	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1439	the maximum amount of time (default C<0>, meaning infinity) spent in
		1440	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1441	of time C<poll_cb> is allowed to use).
815		1442
816	IO::AIO::poll_wait, IO::AIO::poll_cb	1443	Setting C<max_poll_time> to a non-zero value creates an overhead of one
817	while IO::AIO::nreqs;	1444	syscall per request processed, which is not normally a problem unless your
		1445	callbacks are really really fast or your OS is really really slow (I am
		1446	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
818		1447
819	=item IO::AIO::poll	1448	Setting these is useful if you want to ensure some level of
		1449	interactiveness when perl is not fast enough to process all requests in
		1450	time.
820		1451
821	Waits until some requests have been handled.	1452	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
822		1453
823	Strictly equivalent to:	1454	Example: Install an Event watcher that automatically calls
		1455	IO::AIO::poll_cb with low priority, to ensure that other parts of the
		1456	program get the CPU sometimes even under high AIO load.
824		1457
825	IO::AIO::poll_wait, IO::AIO::poll_cb	1458	# try not to spend much more than 0.1s in poll_cb
826	if IO::AIO::nreqs;	1459	IO::AIO::max_poll_time 0.1;
		1460
		1461	# use a low priority so other tasks have priority
		1462	Event->io (fd => IO::AIO::poll_fileno,
		1463	poll => 'r', nice => 1,
		1464	cb => &IO::AIO::poll_cb);
		1465
		1466	=back
		1467
		1468	=head3 CONTROLLING THE NUMBER OF THREADS
		1469
		1470	=over
827		1471
828	=item IO::AIO::min_parallel $nthreads	1472	=item IO::AIO::min_parallel $nthreads
829		1473
830	Set the minimum number of AIO threads to C<$nthreads>. The current	1474	Set the minimum number of AIO threads to C<$nthreads>. The current
831	default is C<8>, which means eight asynchronous operations can execute	1475	default is C<8>, which means eight asynchronous operations can execute
832	concurrently at any one time (the number of outstanding requests,	1476	concurrently at any one time (the number of outstanding requests,
833	however, is unlimited).	1477	however, is unlimited).
834		1478
835	IO::AIO starts threads only on demand, when an AIO request is queued and	1479	IO::AIO starts threads only on demand, when an AIO request is queued and
836	no free thread exists.	1480	no free thread exists. Please note that queueing up a hundred requests can
		1481	create demand for a hundred threads, even if it turns out that everything
		1482	is in the cache and could have been processed faster by a single thread.
837		1483
838	It is recommended to keep the number of threads relatively low, as some	1484	It is recommended to keep the number of threads relatively low, as some
839	Linux kernel versions will scale negatively with the number of threads	1485	Linux kernel versions will scale negatively with the number of threads
840	(higher parallelity => MUCH higher latency). With current Linux 2.6	1486	(higher parallelity => MUCH higher latency). With current Linux 2.6
841	versions, 4-32 threads should be fine.	1487	versions, 4-32 threads should be fine.
…		…
855	This module automatically runs C<max_parallel 0> at program end, to ensure	1501	This module automatically runs C<max_parallel 0> at program end, to ensure
856	that all threads are killed and that there are no outstanding requests.	1502	that all threads are killed and that there are no outstanding requests.
857		1503
858	Under normal circumstances you don't need to call this function.	1504	Under normal circumstances you don't need to call this function.
859		1505
		1506	=item IO::AIO::max_idle $nthreads
		1507
		1508	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1509	threads that did not get a request to process within 10 seconds). That
		1510	means if a thread becomes idle while C<$nthreads> other threads are also
		1511	idle, it will free its resources and exit.
		1512
		1513	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1514	to allow for extremely high load situations, but want to free resources
		1515	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1516
		1517	The default is probably ok in most situations, especially if thread
		1518	creation is fast. If thread creation is very slow on your system you might
		1519	want to use larger values.
		1520
860	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	1521	=item IO::AIO::max_outstanding $maxreqs
861		1522
862	[REMOVED]	1523	This is a very bad function to use in interactive programs because it
		1524	blocks, and a bad way to reduce concurrency because it is inexact: Better
		1525	use an C<aio_group> together with a feed callback.
863		1526
864	Pre-2.x versions used max_outstanding for a crude request queue length limit.
865
866	In 2.x+ you are advised to use a group and a feeder to limit
867	concurrency. The max_outstanding feature ran very unstable (endless
868	recursions causing segfaults, bad interaction with groups etc.) and was
869	removed.
870
871	I am deeply sorry, but I am still on the hunt for a good limiting interface.
872
873	Original description was as follows:
874
875	Sets the maximum number of outstanding requests to C<$nreqs>. If you try	1527	Sets the maximum number of outstanding requests to C<$nreqs>. If you
876	to queue up more than this number of requests, the caller will block until	1528	do queue up more than this number of requests, the next call to the
877	some requests have been handled.	1529	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		1530	function will block until the limit is no longer exceeded.
		1531
		1532	The default value is very large, so there is no practical limit on the
		1533	number of outstanding requests.
		1534
		1535	You can still queue as many requests as you want. Therefore,
		1536	C<max_outstanding> is mainly useful in simple scripts (with low values) or
		1537	as a stop gap to shield against fatal memory overflow (with large values).
878		1538
879	=back	1539	=back
880		1540
		1541	=head3 STATISTICAL INFORMATION
		1542
		1543	=over
		1544
		1545	=item IO::AIO::nreqs
		1546
		1547	Returns the number of requests currently in the ready, execute or pending
		1548	states (i.e. for which their callback has not been invoked yet).
		1549
		1550	Example: wait till there are no outstanding requests anymore:
		1551
		1552	IO::AIO::poll_wait, IO::AIO::poll_cb
		1553	while IO::AIO::nreqs;
		1554
		1555	=item IO::AIO::nready
		1556
		1557	Returns the number of requests currently in the ready state (not yet
		1558	executed).
		1559
		1560	=item IO::AIO::npending
		1561
		1562	Returns the number of requests currently in the pending state (executed,
		1563	but not yet processed by poll_cb).
		1564
		1565	=back
		1566
		1567	=head3 MISCELLANEOUS FUNCTIONS
		1568
		1569	IO::AIO implements some functions that might be useful, but are not
		1570	asynchronous.
		1571
		1572	=over 4
		1573
		1574	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1575
		1576	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1577	but is blocking (this makes most sense if you know the input data is
		1578	likely cached already and the output filehandle is set to non-blocking
		1579	operations).
		1580
		1581	Returns the number of bytes copied, or C<-1> on error.
		1582
		1583	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1584
		1585	Simply calls the C<posix_fadvise> function (see it's
		1586	manpage for details). The following advice constants are
		1587	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1588	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1589	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1590
		1591	On systems that do not implement C<posix_fadvise>, this function returns
		1592	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1593
		1594	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1595
		1596	Memory-maps a file (or anonymous memory range) and attaches it to the
		1597	given C<$scalar>, which will act like a string scalar.
		1598
		1599	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1600	change the string length, and most read-only operations such as copying it
		1601	or searching it with regexes and so on.
		1602
		1603	Anything else is unsafe and will, at best, result in memory leaks.
		1604
		1605	The memory map associated with the C<$scalar> is automatically removed
		1606	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1607	C<IO::AIO::munmap> functions are called.
		1608
		1609	This calls the C<mmap>(2) function internally. See your system's manual
		1610	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1611
		1612	The C<$length> must be larger than zero and smaller than the actual
		1613	filesize.
		1614
		1615	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1616	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1617
		1618	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1619	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1620	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1621	(which is set to C<MAP_ANON> if your system only provides this
		1622	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1623	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1624	C<IO::AIO::MAP_NONBLOCK>
		1625
		1626	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1627
		1628	C<$offset> is the offset from the start of the file - it generally must be
		1629	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1630
		1631	Example:
		1632
		1633	use Digest::MD5;
		1634	use IO::AIO;
		1635
		1636	open my $fh, "<verybigfile"
		1637	or die "$!";
		1638
		1639	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1640	or die "verybigfile: $!";
		1641
		1642	my $fast_md5 = md5 $data;
		1643
		1644	=item IO::AIO::munmap $scalar
		1645
		1646	Removes a previous mmap and undefines the C<$scalar>.
		1647
		1648	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1649
		1650	Calls the C<munlock> function, undoing the effects of a previous
		1651	C<aio_mlock> call (see its description for details).
		1652
		1653	=item IO::AIO::munlockall
		1654
		1655	Calls the C<munlockall> function.
		1656
		1657	On systems that do not implement C<munlockall>, this function returns
		1658	ENOSYS, otherwise the return value of C<munlockall>.
		1659
		1660	=back
		1661
881	=cut	1662	=cut
882		1663
883	# support function to convert a fd into a perl filehandle
884	sub _fd2fh {
885	return undef if $_[0] < 0;
886
887	# try to generate nice filehandles
888	my $sym = "IO::AIO::fd#$_[0]";
889	local *$sym;
890
891	open *$sym, "+<&=$_[0]" # usually works under any unix
892	or open *$sym, "<&=$_[0]" # cygwin needs this
893	or open *$sym, ">&=$_[0]" # or this
894	or return undef;
895
896	*$sym
897	}
898
899	min_parallel 8;	1664	min_parallel 8;
900		1665
901	END {	1666	END { flush }
902	max_parallel 0;
903	}
904		1667
905	1;	1668	1;
		1669
		1670	=head1 EVENT LOOP INTEGRATION
		1671
		1672	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1673	automatically into many event loops:
		1674
		1675	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1676	use AnyEvent::AIO;
		1677
		1678	You can also integrate IO::AIO manually into many event loops, here are
		1679	some examples of how to do this:
		1680
		1681	# EV integration
		1682	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1683
		1684	# Event integration
		1685	Event->io (fd => IO::AIO::poll_fileno,
		1686	poll => 'r',
		1687	cb => \&IO::AIO::poll_cb);
		1688
		1689	# Glib/Gtk2 integration
		1690	add_watch Glib::IO IO::AIO::poll_fileno,
		1691	in => sub { IO::AIO::poll_cb; 1 };
		1692
		1693	# Tk integration
		1694	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1695	readable => \&IO::AIO::poll_cb);
		1696
		1697	# Danga::Socket integration
		1698	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1699	\&IO::AIO::poll_cb);
906		1700
907	=head2 FORK BEHAVIOUR	1701	=head2 FORK BEHAVIOUR
908		1702
909	This module should do "the right thing" when the process using it forks:	1703	This module should do "the right thing" when the process using it forks:
910		1704
…		…
928	bytes of memory. In addition, stat requests need a stat buffer (possibly	1722	bytes of memory. In addition, stat requests need a stat buffer (possibly
929	a few hundred bytes), readdir requires a result buffer and so on. Perl	1723	a few hundred bytes), readdir requires a result buffer and so on. Perl
930	scalars and other data passed into aio requests will also be locked and	1724	scalars and other data passed into aio requests will also be locked and
931	will consume memory till the request has entered the done state.	1725	will consume memory till the request has entered the done state.
932		1726
933	This is now awfully much, so queuing lots of requests is not usually a	1727	This is not awfully much, so queuing lots of requests is not usually a
934	problem.	1728	problem.
935		1729
936	Per-thread usage:	1730	Per-thread usage:
937		1731
938	In the execution phase, some aio requests require more memory for	1732	In the execution phase, some aio requests require more memory for
…		…
943		1737
944	Known bugs will be fixed in the next release.	1738	Known bugs will be fixed in the next release.
945		1739
946	=head1 SEE ALSO	1740	=head1 SEE ALSO
947		1741
948	L<Coro::AIO>.	1742	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1743	more natural syntax.
949		1744
950	=head1 AUTHOR	1745	=head1 AUTHOR
951		1746
952	Marc Lehmann <schmorp@schmorp.de>	1747	Marc Lehmann <schmorp@schmorp.de>
953	http://home.schmorp.de/	1748	http://home.schmorp.de/

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