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Revision 1.103 by root, Tue Jan 23 22:57:34 2007 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 = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51
52	=head1 DESCRIPTION	31	=head1 DESCRIPTION
53		32
54	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
55	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>).
56		36
57	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
58	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
59	will still block, but you can do something else in the meantime. This	39	will still block, but you can do something else in the meantime. This
60	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
62	etc.), but can also be used to easily do operations in parallel that are	42	etc.), but can also be used to easily do operations in parallel that are
63	normally done sequentially, e.g. stat'ing many files, which is much faster	43	normally done sequentially, e.g. stat'ing many files, which is much faster
64	on a RAID volume or over NFS when you do a number of stat operations	44	on a RAID volume or over NFS when you do a number of stat operations
65	concurrently.	45	concurrently.
66		46
67	While most of this works on all types of file descriptors (for example	47	While most of this works on all types of file descriptors (for
68	sockets), using these functions on file descriptors that support	48	example sockets), using these functions on file descriptors that
69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or	49	support nonblocking operation (again, sockets, pipes etc.) is
70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop	50	very inefficient. Use an event loop for that (such as the L<EV>
71	for that (such as the L<Event|Event> module): IO::AIO will naturally fit	51	module): IO::AIO will naturally fit into such an event loop itself.
72	into such an event loop itself.
73		52
74	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
75	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
76	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
77	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
…		…
79	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
80	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
81	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
82	using threads anyway.	61	using threads anyway.
83		62
84	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,
85	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
86	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
87	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
88		67
89	=head2 EXAMPLE	68	=head2 EXAMPLE
90		69
91	This is a simple example that uses the Event module and loads	70	This is a simple example that uses the EV module and loads
92	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
93		72
94	use Fcntl;	73	use Fcntl;
95	use Event;	74	use EV;
96	use IO::AIO;	75	use IO::AIO;
97		76
98	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
99	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
100	poll => 'r',
101	cb => \&IO::AIO::poll_cb);
102		79
103	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105	my $fh = shift	82	my $fh = shift
106	or die "error while opening: $!";	83	or die "error while opening: $!";
107		84
108	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
109	my $size = -s $fh;	86	my $size = -s $fh;
…		…
118		95
119	# file contents now in $contents	96	# file contents now in $contents
120	print $contents;	97	print $contents;
121		98
122	# exit event loop and program	99	# exit event loop and program
123	Event::unloop;	100	EV::unloop;
124	};	101	};
125	};	102	};
126		103
127	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
128	# check for sockets etc. etc.	105	# check for sockets etc. etc.
129		106
130	# process events as long as there are some:	107	# process events as long as there are some:
131	Event::loop;	108	EV::loop;
132		109
133	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
134		111
135	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
136	directly visible to Perl.	113	directly visible to Perl.
…		…
184		161
185	=cut	162	=cut
186		163
187	package IO::AIO;	164	package IO::AIO;
188		165
189	no warnings;	166	use Carp ();
190	use strict 'vars';	167
		168	use common::sense;
191		169
192	use base 'Exporter';	170	use base 'Exporter';
193		171
194	BEGIN {	172	BEGIN {
195	our $VERSION = '2.33';	173	our $VERSION = '3.65';
196		174
197	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
198	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
199	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link	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
200	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir);	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
		183	aio_statvfs);
		184
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle
204	nreqs nready npending nthreads	188	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	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
206		194
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		196
209	require XSLoader;	197	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
211	}	199	}
212		200
213	=head1 FUNCTIONS	201	=head1 FUNCTIONS
		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, $length = undef
		271	IO::AIO::munlockall
214		272
215	=head2 AIO REQUEST FUNCTIONS	273	=head2 AIO REQUEST FUNCTIONS
216		274
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	275	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	276	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	277	and they all accept an additional (and optional) C<$callback> argument
220	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
221	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
222	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
223	syscall has been executed asynchronously.	281	syscall has been executed asynchronously.
224		282
225	All functions expecting a filehandle keep a copy of the filehandle	283	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	284	internally until the request has finished.
227		285
…		…
241	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
242	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)
243	use something else to ensure your scalar has the correct contents.	301	use something else to ensure your scalar has the correct contents.
244		302
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	303	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	304	handles correctly whether it is set or not.
247		305
248	=over 4	306	=over 4
249		307
250	=item $prev_pri = aioreq_pri [$pri]	308	=item $prev_pri = aioreq_pri [$pri]
251		309
…		…
271	aio_read $_[0], ..., sub {	329	aio_read $_[0], ..., sub {
272	...	330	...
273	};	331	};
274	};	332	};
275		333
		334
276	=item aioreq_nice $pri_adjust	335	=item aioreq_nice $pri_adjust
277		336
278	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
279	priority, so the effect is cumulative.	338	priority, so the effect is cumulative.
		339
280		340
281	=item aio_open $pathname, $flags, $mode, $callback->($fh)	341	=item aio_open $pathname, $flags, $mode, $callback->($fh)
282		342
283	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
284	created filehandle for the file.	344	created filehandle for the file.
…		…
296	by the umask in effect then the request is being executed, so better never	356	by the umask in effect then the request is being executed, so better never
297	change the umask.	357	change the umask.
298		358
299	Example:	359	Example:
300		360
301	aio_open "/etc/passwd", O_RDONLY, 0, sub {	361	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
302	if ($_[0]) {	362	if ($_[0]) {
303	print "open successful, fh is $_[0]\n";	363	print "open successful, fh is $_[0]\n";
304	...	364	...
305	} else {	365	} else {
306	die "open failed: $!\n";	366	die "open failed: $!\n";
307	}	367	}
308	};	368	};
309		369
		370
310	=item aio_close $fh, $callback->($status)	371	=item aio_close $fh, $callback->($status)
311		372
312	Asynchronously close a file and call the callback with the result	373	Asynchronously close a file and call the callback with the result
313	code. I<WARNING:> although accepted, you should not pass in a perl	374	code.
314	filehandle here, as perl will likely close the file descriptor another
315	time when the filehandle is destroyed. Normally, you can safely call perls
316	C<close> or just let filehandles go out of scope.
317		375
318	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
319	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
320		387
321	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	388	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322		389
323	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	390	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
324		391
325	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
326	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<$dataoffset>
327	callback without the actual number of bytes read (or -1 on error, just	394	and calls the callback without the actual number of bytes read (or -1 on
328	like the syscall).	395	error, just like the syscall).
		396
		397	C<aio_read> will, like C<sysread>, shrink or grow the C<$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<$data>.
329		409
330	The C<$data> scalar I<MUST NOT> be modified in any way while the request	410	The C<$data> scalar I<MUST NOT> be modified in any way while the request
331	is outstanding. Modifying it can result in segfaults or WW3 (if the	411	is outstanding. Modifying it can result in segfaults or World War III (if
332	necessary/optional hardware is installed).	412	the necessary/optional hardware is installed).
333		413
334	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	414	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
335	offset C<0> within the scalar:	415	offset C<0> within the scalar:
336		416
337	aio_read $fh, 7, 15, $buffer, 0, sub {	417	aio_read $fh, 7, 15, $buffer, 0, sub {
338	$_[0] > 0 or die "read error: $!";	418	$_[0] > 0 or die "read error: $!";
339	print "read $_[0] bytes: <$buffer>\n";	419	print "read $_[0] bytes: <$buffer>\n";
340	};	420	};
		421
341		422
342	=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)
343		424
344	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
345	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
…		…
347	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
348	other.	429	other.
349		430
350	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
351	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
352	socket, and C<$in_fh> should refer to mmap'able file.	433	socket, and C<$in_fh> should refer to an mmap'able file.
353		434
354	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>,
355	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
356	regardless of the limitations of the operating system.	438	filehandle regardless of the limitations of the operating system.
357		439
358	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
359	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
360	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
361	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
362	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
363	read.	445	read.
		446
364		447
365	=item aio_readahead $fh,$offset,$length, $callback->($retval)	448	=item aio_readahead $fh,$offset,$length, $callback->($retval)
366		449
367	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
368	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>
…		…
374	file. The current file offset of the file is left unchanged.	457	file. The current file offset of the file is left unchanged.
375		458
376	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
377	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.
378		461
		462
379	=item aio_stat $fh_or_path, $callback->($status)	463	=item aio_stat $fh_or_path, $callback->($status)
380		464
381	=item aio_lstat $fh, $callback->($status)	465	=item aio_lstat $fh, $callback->($status)
382		466
383	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
…		…
396	aio_stat "/etc/passwd", sub {	480	aio_stat "/etc/passwd", sub {
397	$_[0] and die "stat failed: $!";	481	$_[0] and die "stat failed: $!";
398	print "size is ", -s _, "\n";	482	print "size is ", -s _, "\n";
399	};	483	};
400		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
401	=item aio_unlink $pathname, $callback->($status)	572	=item aio_unlink $pathname, $callback->($status)
402		573
403	Asynchronously unlink (delete) a file and call the callback with the	574	Asynchronously unlink (delete) a file and call the callback with the
404	result code.	575	result code.
405		576
		577
406	=item aio_mknod $path, $mode, $dev, $callback->($status)	578	=item aio_mknod $path, $mode, $dev, $callback->($status)
407		579
408	[EXPERIMENTAL]	580	[EXPERIMENTAL]
409		581
410	Asynchronously create a device node (or fifo). See mknod(2).	582	Asynchronously create a device node (or fifo). See mknod(2).
411		583
412	The only (POSIX-) portable way of calling this function is:	584	The only (POSIX-) portable way of calling this function is:
413		585
414	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	586	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		587
415		588
416	=item aio_link $srcpath, $dstpath, $callback->($status)	589	=item aio_link $srcpath, $dstpath, $callback->($status)
417		590
418	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
419	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.
420		593
		594
421	=item aio_symlink $srcpath, $dstpath, $callback->($status)	595	=item aio_symlink $srcpath, $dstpath, $callback->($status)
422		596
423	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
424	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.
		599
425		600
426	=item aio_readlink $path, $callback->($link)	601	=item aio_readlink $path, $callback->($link)
427		602
428	Asynchronously read the symlink specified by C<$path> and pass it to	603	Asynchronously read the symlink specified by C<$path> and pass it to
429	the callback. If an error occurs, nothing or undef gets passed to the	604	the callback. If an error occurs, nothing or undef gets passed to the
430	callback.	605	callback.
431		606
		607
432	=item aio_rename $srcpath, $dstpath, $callback->($status)	608	=item aio_rename $srcpath, $dstpath, $callback->($status)
433		609
434	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
435	rename(2) and call the callback with the result code.	611	rename(2) and call the callback with the result code.
		612
436		613
437	=item aio_mkdir $pathname, $mode, $callback->($status)	614	=item aio_mkdir $pathname, $mode, $callback->($status)
438		615
439	Asynchronously mkdir (create) a directory and call the callback with	616	Asynchronously mkdir (create) a directory and call the callback with
440	the result code. C<$mode> will be modified by the umask at the time the	617	the result code. C<$mode> will be modified by the umask at the time the
441	request is executed, so do not change your umask.	618	request is executed, so do not change your umask.
442		619
		620
443	=item aio_rmdir $pathname, $callback->($status)	621	=item aio_rmdir $pathname, $callback->($status)
444		622
445	Asynchronously rmdir (delete) a directory and call the callback with the	623	Asynchronously rmdir (delete) a directory and call the callback with the
446	result code.	624	result code.
		625
447		626
448	=item aio_readdir $pathname, $callback->($entries)	627	=item aio_readdir $pathname, $callback->($entries)
449		628
450	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
451	directory (i.e. opendir + readdir + closedir). The entries will not be	630	directory (i.e. opendir + readdir + closedir). The entries will not be
452	sorted, and will B<NOT> include the C<.> and C<..> entries.	631	sorted, and will B<NOT> include the C<.> and C<..> entries.
453		632
454	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
455	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
456		702
457	=item aio_load $path, $data, $callback->($status)	703	=item aio_load $path, $data, $callback->($status)
458		704
459	This is a composite request that tries to fully load the given file into	705	This is a composite request that tries to fully load the given file into
460	memory. Status is the same as with aio_read.	706	memory. Status is the same as with aio_read.
461		707
462	=cut	708	=cut
463		709
464	sub aio_load($$;$) {	710	sub aio_load($$;$) {
465	aio_block {
466	my ($path, undef, $cb) = @_;	711	my ($path, undef, $cb) = @_;
467	my $data = \$_[1];	712	my $data = \$_[1];
468		713
469	my $pri = aioreq_pri;	714	my $pri = aioreq_pri;
470	my $grp = aio_group $cb;	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);
471		721
472	aioreq_pri $pri;	722	aioreq_pri $pri;
473	add $grp aio_open $path, O_RDONLY, 0, sub {
474	my $fh = shift
475	or return $grp->result (-1);
476
477	aioreq_pri $pri;
478	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	723	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
479	$grp->result ($_[0]);	724	$grp->result ($_[0]);
480	};
481	};	725	};
482
483	$grp
484	}	726	};
		727
		728	$grp
485	}	729	}
486		730
487	=item aio_copy $srcpath, $dstpath, $callback->($status)	731	=item aio_copy $srcpath, $dstpath, $callback->($status)
488		732
489	Try to copy the I<file> (directories not supported as either source or	733	Try to copy the I<file> (directories not supported as either source or
490	destination) from C<$srcpath> to C<$dstpath> and call the callback with	734	destination) from C<$srcpath> to C<$dstpath> and call the callback with
491	the C<0> (error) or C<-1> ok.	735	a status of C<0> (ok) or C<-1> (error, see C<$!>).
492		736
493	This is a composite request that it creates the destination file with	737	This is a composite request that creates the destination file with
494	mode 0200 and copies the contents of the source file into it using	738	mode 0200 and copies the contents of the source file into it using
495	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	739	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
496	uid/gid, in that order.	740	uid/gid, in that order.
497		741
498	If an error occurs, the partial destination file will be unlinked, if	742	If an error occurs, the partial destination file will be unlinked, if
…		…
500	errors are being ignored.	744	errors are being ignored.
501		745
502	=cut	746	=cut
503		747
504	sub aio_copy($$;$) {	748	sub aio_copy($$;$) {
505	aio_block {
506	my ($src, $dst, $cb) = @_;	749	my ($src, $dst, $cb) = @_;
507		750
508	my $pri = aioreq_pri;	751	my $pri = aioreq_pri;
509	my $grp = aio_group $cb;	752	my $grp = aio_group $cb;
510		753
511	aioreq_pri $pri;	754	aioreq_pri $pri;
512	add $grp aio_open $src, O_RDONLY, 0, sub {	755	add $grp aio_open $src, O_RDONLY, 0, sub {
513	if (my $src_fh = $_[0]) {	756	if (my $src_fh = $_[0]) {
514	my @stat = stat $src_fh;	757	my @stat = stat $src_fh; # hmm, might block over nfs?
515		758
516	aioreq_pri $pri;	759	aioreq_pri $pri;
517	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	760	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
518	if (my $dst_fh = $_[0]) {	761	if (my $dst_fh = $_[0]) {
519	aioreq_pri $pri;	762	aioreq_pri $pri;
520	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	763	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
521	if ($_[0] == $stat[7]) {	764	if ($_[0] == $stat[7]) {
522	$grp->result (0);	765	$grp->result (0);
523	close $src_fh;	766	close $src_fh;
524		767
525	# those should not normally block. should. should.
526	utime $stat[8], $stat[9], $dst;
527	chmod $stat[2] & 07777, $dst_fh;
528	chown $stat[4], $stat[5], $dst_fh;
529	close $dst_fh;
530	} else {	768	my $ch = sub {
531	$grp->result (-1);
532	close $src_fh;
533	close $dst_fh;
534
535	aioreq $pri;	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;
536	add $grp aio_unlink $dst;	774	add $grp aio_close $dst_fh;
		775	}
		776	};
537	}	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;
538	};	795	}
539	} else {
540	$grp->result (-1);
541	}	796	};
		797	} else {
		798	$grp->result (-1);
542	},	799	}
543
544	} else {
545	$grp->result (-1);
546	}	800	},
		801
		802	} else {
		803	$grp->result (-1);
547	};	804	}
548
549	$grp
550	}	805	};
		806
		807	$grp
551	}	808	}
552		809
553	=item aio_move $srcpath, $dstpath, $callback->($status)	810	=item aio_move $srcpath, $dstpath, $callback->($status)
554		811
555	Try to move the I<file> (directories not supported as either source or	812	Try to move the I<file> (directories not supported as either source or
556	destination) from C<$srcpath> to C<$dstpath> and call the callback with	813	destination) from C<$srcpath> to C<$dstpath> and call the callback with
557	the C<0> (error) or C<-1> ok.	814	a status of C<0> (ok) or C<-1> (error, see C<$!>).
558		815
559	This is a composite request that tries to rename(2) the file first. If	816	This is a composite request that tries to rename(2) the file first; if
560	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	817	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
561	that is successful, unlinking the C<$srcpath>.	818	that is successful, unlinks the C<$srcpath>.
562		819
563	=cut	820	=cut
564		821
565	sub aio_move($$;$) {	822	sub aio_move($$;$) {
566	aio_block {
567	my ($src, $dst, $cb) = @_;	823	my ($src, $dst, $cb) = @_;
568		824
569	my $pri = aioreq_pri;	825	my $pri = aioreq_pri;
570	my $grp = aio_group $cb;	826	my $grp = aio_group $cb;
571		827
572	aioreq_pri $pri;	828	aioreq_pri $pri;
573	add $grp aio_rename $src, $dst, sub {	829	add $grp aio_rename $src, $dst, sub {
574	if ($_[0] && $! == EXDEV) {	830	if ($_[0] && $! == EXDEV) {
575	aioreq_pri $pri;	831	aioreq_pri $pri;
576	add $grp aio_copy $src, $dst, sub {	832	add $grp aio_copy $src, $dst, sub {
577	$grp->result ($_[0]);
578
579	if (!$_[0]) {
580	aioreq_pri $pri;
581	add $grp aio_unlink $src;
582	}
583	};
584	} else {
585	$grp->result ($_[0]);	833	$grp->result ($_[0]);
		834
		835	if (!$_[0]) {
		836	aioreq_pri $pri;
		837	add $grp aio_unlink $src;
		838	}
586	}	839	};
		840	} else {
		841	$grp->result ($_[0]);
587	};	842	}
588
589	$grp
590	}	843	};
		844
		845	$grp
591	}	846	}
592		847
593	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	848	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
594		849
595	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
…		…
615		870
616	Implementation notes.	871	Implementation notes.
617		872
618	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.
619		874
		875	If readdir returns file type information, then this is used directly to
		876	find directories.
		877
620	After reading the directory, the modification time, size etc. of the	878	Otherwise, after reading the directory, the modification time, size etc.
621	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
622	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
623	entries are directories (if >= 2). Otherwise, no knowledge of the number	881	how many entries are directories (if >= 2). Otherwise, no knowledge of the
624	of subdirectories will be assumed.	882	number of subdirectories will be assumed.
625		883
626	Then entries will be sorted into likely directories (everything without	884	Then entries will be sorted into likely directories a non-initial dot
627	a non-initial dot currently) and likely non-directories (everything	885	currently) and likely non-directories (see C<aio_readdirx>). Then every
628	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,
629	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
630	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
631	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
632	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
633	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.
634		893
635	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
636	rest of the entries is assumed to be non-directories.	895	rest of the entries is assumed to be non-directories.
637		896
638	This only works with certainty on POSIX (= UNIX) filesystems, which	897	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
643	directory counting heuristic.	902	directory counting heuristic.
644		903
645	=cut	904	=cut
646		905
647	sub aio_scandir($$;$) {	906	sub aio_scandir($$;$) {
648	aio_block {
649	my ($path, $maxreq, $cb) = @_;	907	my ($path, $maxreq, $cb) = @_;
650		908
651	my $pri = aioreq_pri;	909	my $pri = aioreq_pri;
652		910
653	my $grp = aio_group $cb;	911	my $grp = aio_group $cb;
654		912
655	$maxreq = 4 if $maxreq <= 0;	913	$maxreq = 4 if $maxreq <= 0;
656		914
657	# stat once	915	# stat once
		916	aioreq_pri $pri;
		917	add $grp aio_stat $path, sub {
		918	return $grp->result () if $_[0];
		919	my $now = time;
		920	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		921
		922	# read the directory entries
658	aioreq_pri $pri;	923	aioreq_pri $pri;
659	add $grp aio_stat $path, sub {	924	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		925	my $entries = shift
660	return $grp->result () if $_[0];	926	or return $grp->result ();
661	my $now = time;
662	my $hash1 = join ":", (stat _)[0,1,3,7,9];
663		927
664	# read the directory entries	928	# stat the dir another time
665	aioreq_pri $pri;	929	aioreq_pri $pri;
666	add $grp aio_readdir $path, sub {
667	my $entries = shift
668	or return $grp->result ();
669
670	# stat the dir another time
671	aioreq_pri $pri;
672	add $grp aio_stat $path, sub {	930	add $grp aio_stat $path, sub {
673	my $hash2 = join ":", (stat _)[0,1,3,7,9];	931	my $hash2 = join ":", (stat _)[0,1,3,7,9];
674		932
675	my $ndirs;	933	my $ndirs;
676		934
677	# take the slow route if anything looks fishy	935	# take the slow route if anything looks fishy
678	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	936	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
679	$ndirs = -1;	937	$ndirs = -1;
680	} else {	938	} else {
681	# if nlink == 2, we are finished	939	# if nlink == 2, we are finished
682	# on non-posix-fs's, we rely on nlink < 2	940	# for non-posix-fs's, we rely on nlink < 2
683	$ndirs = (stat _)[3] - 2	941	$ndirs = (stat _)[3] - 2
684	or return $grp->result ([], $entries);	942	or return $grp->result ([], $entries);
685	}	943	}
686		944
687	# sort into likely dirs and likely nondirs
688	# dirs == files without ".", short entries first
689	$entries = [map $_->[0],
690	sort { $b->[1] cmp $a->[1] }
691	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
692	@$entries];
693
694	my (@dirs, @nondirs);	945	my (@dirs, @nondirs);
695		946
696	my $statgrp = add $grp aio_group sub {	947	my $statgrp = add $grp aio_group sub {
697	$grp->result (\@dirs, \@nondirs);	948	$grp->result (\@dirs, \@nondirs);
698	};	949	};
699		950
700	limit $statgrp $maxreq;	951	limit $statgrp $maxreq;
701	feed $statgrp sub {	952	feed $statgrp sub {
702	return unless @$entries;	953	return unless @$entries;
703	my $entry = pop @$entries;	954	my $entry = shift @$entries;
704		955
705	aioreq_pri $pri;	956	aioreq_pri $pri;
706	add $statgrp aio_stat "$path/$entry/.", sub {	957	add $statgrp aio_stat "$path/$entry/.", sub {
707	if ($_[0] < 0) {	958	if ($_[0] < 0) {
708	push @nondirs, $entry;	959	push @nondirs, $entry;
709	} else {	960	} else {
710	# need to check for real directory	961	# need to check for real directory
711	aioreq_pri $pri;	962	aioreq_pri $pri;
712	add $statgrp aio_lstat "$path/$entry", sub {	963	add $statgrp aio_lstat "$path/$entry", sub {
713	if (-d _) {	964	if (-d _) {
714	push @dirs, $entry;	965	push @dirs, $entry;
715		966
716	unless (--$ndirs) {	967	unless (--$ndirs) {
717	push @nondirs, @$entries;	968	push @nondirs, @$entries;
718	feed $statgrp;	969	feed $statgrp;
719	}
720	} else {
721	push @nondirs, $entry;
722	}	970	}
		971	} else {
		972	push @nondirs, $entry;
723	}	973	}
724	}	974	}
725	};	975	}
726	};	976	};
727	};	977	};
728	};	978	};
729	};	979	};
730
731	$grp
732	}	980	};
		981
		982	$grp
733	}	983	}
734		984
735	=item aio_rmtree $path, $callback->($status)	985	=item aio_rmtree $path, $callback->($status)
736		986
737	Delete a directory tree starting (and including) C<$path>, return the	987	Delete a directory tree starting (and including) C<$path>, return the
…		…
741		991
742	=cut	992	=cut
743		993
744	sub aio_rmtree;	994	sub aio_rmtree;
745	sub aio_rmtree($;$) {	995	sub aio_rmtree($;$) {
746	aio_block {
747	my ($path, $cb) = @_;	996	my ($path, $cb) = @_;
748		997
749	my $pri = aioreq_pri;	998	my $pri = aioreq_pri;
750	my $grp = aio_group $cb;	999	my $grp = aio_group $cb;
751		1000
752	aioreq_pri $pri;	1001	aioreq_pri $pri;
753	add $grp aio_scandir $path, 0, sub {	1002	add $grp aio_scandir $path, 0, sub {
754	my ($dirs, $nondirs) = @_;	1003	my ($dirs, $nondirs) = @_;
755		1004
756	my $dirgrp = aio_group sub {	1005	my $dirgrp = aio_group sub {
757	add $grp aio_rmdir $path, sub {	1006	add $grp aio_rmdir $path, sub {
758	$grp->result ($_[0]);	1007	$grp->result ($_[0]);
759	};
760	};	1008	};
761
762	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
763	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
764
765	add $grp $dirgrp;
766	};	1009	};
767		1010
768	$grp	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;
769	}	1015	};
		1016
		1017	$grp
770	}	1018	}
		1019
		1020	=item aio_sync $callback->($status)
		1021
		1022	Asynchronously call sync and call the callback when finished.
771		1023
772	=item aio_fsync $fh, $callback->($status)	1024	=item aio_fsync $fh, $callback->($status)
773		1025
774	Asynchronously call fsync on the given filehandle and call the callback	1026	Asynchronously call fsync on the given filehandle and call the callback
775	with the fsync result code.	1027	with the fsync result code.
…		…
779	Asynchronously call fdatasync on the given filehandle and call the	1031	Asynchronously call fdatasync on the given filehandle and call the
780	callback with the fdatasync result code.	1032	callback with the fdatasync result code.
781		1033
782	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
783	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;
784		1155
785	=item aio_group $callback->(...)	1156	=item aio_group $callback->(...)
786		1157
787	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
788	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
…		…
838	=item cancel $req	1209	=item cancel $req
839		1210
840	Cancels the request, if possible. Has the effect of skipping execution	1211	Cancels the request, if possible. Has the effect of skipping execution
841	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
842	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
843	untouched. That means that requests that currently execute will not be	1214	untouched (with the exception of readdir). That means that requests that
844	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.
845		1217
846	=item cb $req $callback->(...)	1218	=item cb $req $callback->(...)
847		1219
848	Replace (or simply set) the callback registered to the request.	1220	Replace (or simply set) the callback registered to the request.
849		1221
…		…
900	Their lifetime, simplified, looks like this: when they are empty, they	1272	Their lifetime, simplified, looks like this: when they are empty, they
901	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
902	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
903	exist.	1275	exist.
904		1276
905	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
906	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
907	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
908	itself finish.	1280	further requests to the group. And only when all those requests have
		1281	finished will the the group itself finish.
909		1282
910	=over 4	1283	=over 4
911		1284
912	=item add $grp ...	1285	=item add $grp ...
913		1286
…		…
922	=item $grp->cancel_subs	1295	=item $grp->cancel_subs
923		1296
924	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
925	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.
926		1299
		1300	The group request will finish normally (you cannot add requests to the
		1301	group).
		1302
927	=item $grp->result (...)	1303	=item $grp->result (...)
928		1304
929	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
930	subrequests have finished and set thre groups errno to the current value	1306	subrequests have finished and set the groups errno to the current value
931	of errno (just like calling C<errno> without an error number). By default,	1307	of errno (just like calling C<errno> without an error number). By default,
932	no argument will be passed and errno is zero.	1308	no argument will be passed and errno is zero.
933		1309
934	=item $grp->errno ([$errno])	1310	=item $grp->errno ([$errno])
935		1311
…		…
946	=item feed $grp $callback->($grp)	1322	=item feed $grp $callback->($grp)
947		1323
948	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
949	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,
950	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,
951	this might starve other requests for a potentially long time. For	1327	this might starve other requests for a potentially long time. For example,
952	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,
953	requests, delaying any later requests for a long time.	1329	delaying any later requests for a long time.
954		1330
955	To avoid this, and allow incremental generation of requests, you can	1331	To avoid this, and allow incremental generation of requests, you can
956	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
957	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>,
958	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
…		…
962	not impose any limits).	1338	not impose any limits).
963		1339
964	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
965	automatically removed from the group.	1341	automatically removed from the group.
966		1342
967	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.
968		1345
969	Example:	1346	Example:
970		1347
971	# 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:
972		1349
…		…
984	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
985	the group contains less than this many requests.	1362	the group contains less than this many requests.
986		1363
987	Setting the limit to C<0> will pause the feeding process.	1364	Setting the limit to C<0> will pause the feeding process.
988		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
989	=back	1369	=back
990		1370
991	=head2 SUPPORT FUNCTIONS	1371	=head2 SUPPORT FUNCTIONS
992		1372
993	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1373	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
995	=over 4	1375	=over 4
996		1376
997	=item $fileno = IO::AIO::poll_fileno	1377	=item $fileno = IO::AIO::poll_fileno
998		1378
999	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
1000	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,
1001	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
1002	to call C<poll_cb> to check the results.	1382	you have to call C<poll_cb> to check the results.
1003		1383
1004	See C<poll_cb> for an example.	1384	See C<poll_cb> for an example.
1005		1385
1006	=item IO::AIO::poll_cb	1386	=item IO::AIO::poll_cb
1007		1387
1008	Process some 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
1009	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
		1390	returned earlier for whatever reason. Returns immediately when no events
1010	when no events are outstanding. The amount of events processed depends on	1391	are outstanding. The amount of events processed depends on the settings of
1011	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1392	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1012		1393
1013	If not all requests were processed for whatever reason, the filehandle	1394	If not all requests were processed for whatever reason, the filehandle
1014	will still be ready when C<poll_cb> returns.	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.
1015		1397
1016	Example: Install an Event watcher that automatically calls	1398	Example: Install an Event watcher that automatically calls
1017	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):
1018		1401
1019	Event->io (fd => IO::AIO::poll_fileno,	1402	Event->io (fd => IO::AIO::poll_fileno,
1020	poll => 'r', async => 1,	1403	poll => 'r', async => 1,
1021	cb => \&IO::AIO::poll_cb);	1404	cb => \&IO::AIO::poll_cb);
		1405
		1406	=item IO::AIO::poll_wait
		1407
		1408	If there are any outstanding requests and none of them in the result
		1409	phase, wait till the result filehandle becomes ready for reading (simply
		1410	does a C<select> on the filehandle. This is useful if you want to
		1411	synchronously wait for some requests to finish).
		1412
		1413	See C<nreqs> for an example.
		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
		1424	=item IO::AIO::flush
		1425
		1426	Wait till all outstanding AIO requests have been handled.
		1427
		1428	Strictly equivalent to:
		1429
		1430	IO::AIO::poll_wait, IO::AIO::poll_cb
		1431	while IO::AIO::nreqs;
1022		1432
1023	=item IO::AIO::max_poll_reqs $nreqs	1433	=item IO::AIO::max_poll_reqs $nreqs
1024		1434
1025	=item IO::AIO::max_poll_time $seconds	1435	=item IO::AIO::max_poll_time $seconds
1026		1436
…		…
1051	# use a low priority so other tasks have priority	1461	# use a low priority so other tasks have priority
1052	Event->io (fd => IO::AIO::poll_fileno,	1462	Event->io (fd => IO::AIO::poll_fileno,
1053	poll => 'r', nice => 1,	1463	poll => 'r', nice => 1,
1054	cb => &IO::AIO::poll_cb);	1464	cb => &IO::AIO::poll_cb);
1055		1465
1056	=item IO::AIO::poll_wait	1466	=back
1057
1058	If there are any outstanding requests and none of them in the result
1059	phase, wait till the result filehandle becomes ready for reading (simply
1060	does a C<select> on the filehandle. This is useful if you want to
1061	synchronously wait for some requests to finish).
1062
1063	See C<nreqs> for an example.
1064
1065	=item IO::AIO::poll
1066
1067	Waits until some requests have been handled.
1068
1069	Returns the number of requests processed, but is otherwise strictly
1070	equivalent to:
1071
1072	IO::AIO::poll_wait, IO::AIO::poll_cb
1073
1074	=item IO::AIO::flush
1075
1076	Wait till all outstanding AIO requests have been handled.
1077
1078	Strictly equivalent to:
1079
1080	IO::AIO::poll_wait, IO::AIO::poll_cb
1081	while IO::AIO::nreqs;
1082		1467
1083	=head3 CONTROLLING THE NUMBER OF THREADS	1468	=head3 CONTROLLING THE NUMBER OF THREADS
		1469
		1470	=over
1084		1471
1085	=item IO::AIO::min_parallel $nthreads	1472	=item IO::AIO::min_parallel $nthreads
1086		1473
1087	Set the minimum number of AIO threads to C<$nthreads>. The current	1474	Set the minimum number of AIO threads to C<$nthreads>. The current
1088	default is C<8>, which means eight asynchronous operations can execute	1475	default is C<8>, which means eight asynchronous operations can execute
…		…
1129		1516
1130	The default is probably ok in most situations, especially if thread	1517	The default is probably ok in most situations, especially if thread
1131	creation is fast. If thread creation is very slow on your system you might	1518	creation is fast. If thread creation is very slow on your system you might
1132	want to use larger values.	1519	want to use larger values.
1133		1520
1134	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1521	=item IO::AIO::max_outstanding $maxreqs
1135		1522
1136	This is a very bad function to use in interactive programs because it	1523	This is a very bad function to use in interactive programs because it
1137	blocks, and a bad way to reduce concurrency because it is inexact: Better	1524	blocks, and a bad way to reduce concurrency because it is inexact: Better
1138	use an C<aio_group> together with a feed callback.	1525	use an C<aio_group> together with a feed callback.
1139		1526
1140	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1527	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1141	to queue up more than this number of requests, the next call to the	1528	do queue up more than this number of requests, the next call to the
1142	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1529	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1143	function will block until the limit is no longer exceeded.	1530	function will block until the limit is no longer exceeded.
1144		1531
1145	The default value is very large, so there is no practical limit on the	1532	The default value is very large, so there is no practical limit on the
1146	number of outstanding requests.	1533	number of outstanding requests.
1147		1534
1148	You can still queue as many requests as you want. Therefore,	1535	You can still queue as many requests as you want. Therefore,
1149	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1536	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1150	as a stop gap to shield against fatal memory overflow (with large values).	1537	as a stop gap to shield against fatal memory overflow (with large values).
1151		1538
		1539	=back
		1540
1152	=head3 STATISTICAL INFORMATION	1541	=head3 STATISTICAL INFORMATION
		1542
		1543	=over
1153		1544
1154	=item IO::AIO::nreqs	1545	=item IO::AIO::nreqs
1155		1546
1156	Returns the number of requests currently in the ready, execute or pending	1547	Returns the number of requests currently in the ready, execute or pending
1157	states (i.e. for which their callback has not been invoked yet).	1548	states (i.e. for which their callback has not been invoked yet).
…		…
1171	Returns the number of requests currently in the pending state (executed,	1562	Returns the number of requests currently in the pending state (executed,
1172	but not yet processed by poll_cb).	1563	but not yet processed by poll_cb).
1173		1564
1174	=back	1565	=back
1175		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
1176	=cut	1662	=cut
1177		1663
1178	# support function to convert a fd into a perl filehandle
1179	sub _fd2fh {
1180	return undef if $_[0] < 0;
1181
1182	# try to generate nice filehandles
1183	my $sym = "IO::AIO::fd#$_[0]";
1184	local *$sym;
1185
1186	open *$sym, "+<&=$_[0]" # usually works under any unix
1187	or open *$sym, "<&=$_[0]" # cygwin needs this
1188	or open *$sym, ">&=$_[0]" # or this
1189	or return undef;
1190
1191	*$sym
1192	}
1193
1194	min_parallel 8;	1664	min_parallel 8;
1195		1665
1196	END { flush }	1666	END { flush }
1197		1667
1198	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);
1199		1700
1200	=head2 FORK BEHAVIOUR	1701	=head2 FORK BEHAVIOUR
1201		1702
1202	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:
1203		1704
…		…
1221	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
1222	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
1223	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
1224	will consume memory till the request has entered the done state.	1725	will consume memory till the request has entered the done state.
1225		1726
1226	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
1227	problem.	1728	problem.
1228		1729
1229	Per-thread usage:	1730	Per-thread usage:
1230		1731
1231	In the execution phase, some aio requests require more memory for	1732	In the execution phase, some aio requests require more memory for
…		…
1236		1737
1237	Known bugs will be fixed in the next release.	1738	Known bugs will be fixed in the next release.
1238		1739
1239	=head1 SEE ALSO	1740	=head1 SEE ALSO
1240		1741
1241	L<Coro::AIO>.	1742	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1743	more natural syntax.
1242		1744
1243	=head1 AUTHOR	1745	=head1 AUTHOR
1244		1746
1245	Marc Lehmann <schmorp@schmorp.de>	1747	Marc Lehmann <schmorp@schmorp.de>
1246	http://home.schmorp.de/	1748	http://home.schmorp.de/

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