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Revision 1.156 by root, Tue Jun 16 23:41:59 2009 UTC vs.
Revision 1.260 by root, Sun May 1 17:19:39 2016 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
…		…
25	my $req = aio_unlink "/tmp/file", sub { };	25	my $req = aio_unlink "/tmp/file", sub { };
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
31	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32	use AnyEvent::AIO;
33
34	# EV integration
35	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37	# Event integration
38	Event->io (fd => IO::AIO::poll_fileno,
39	poll => 'r',
40	cb => \&IO::AIO::poll_cb);
41
42	# Glib/Gtk2 integration
43	add_watch Glib::IO IO::AIO::poll_fileno,
44	in => sub { IO::AIO::poll_cb; 1 };
45
46	# Tk integration
47	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48	readable => \&IO::AIO::poll_cb);
49
50	# Danga::Socket integration
51	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52	\&IO::AIO::poll_cb);
53		30
54	=head1 DESCRIPTION	31	=head1 DESCRIPTION
55		32
56	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
57	operating system supports. It is implemented as an interface to C<libeio>	34	operating system supports. It is implemented as an interface to C<libeio>
…		…
91	=head2 EXAMPLE	68	=head2 EXAMPLE
92		69
93	This is a simple example that uses the EV module and loads	70	This is a simple example that uses the EV module and loads
94	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
95		72
96	use Fcntl;
97	use EV;	73	use EV;
98	use IO::AIO;	74	use IO::AIO;
99		75
100	# register the IO::AIO callback with EV	76	# register the IO::AIO callback with EV
101	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	77	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102		78
103	# queue the request to open /etc/passwd	79	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	80	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105	my $fh = shift	81	my $fh = shift
106	or die "error while opening: $!";	82	or die "error while opening: $!";
107		83
108	# stat'ing filehandles is generally non-blocking	84	# stat'ing filehandles is generally non-blocking
109	my $size = -s $fh;	85	my $size = -s $fh;
…		…
118		94
119	# file contents now in $contents	95	# file contents now in $contents
120	print $contents;	96	print $contents;
121		97
122	# exit event loop and program	98	# exit event loop and program
123	EV::unloop;	99	EV::break;
124	};	100	};
125	};	101	};
126		102
127	# possibly queue up other requests, or open GUI windows,	103	# possibly queue up other requests, or open GUI windows,
128	# check for sockets etc. etc.	104	# check for sockets etc. etc.
129		105
130	# process events as long as there are some:	106	# process events as long as there are some:
131	EV::loop;	107	EV::run;
132		108
133	=head1 REQUEST ANATOMY AND LIFETIME	109	=head1 REQUEST ANATOMY AND LIFETIME
134		110
135	Every C<aio_*> function creates a request. which is a C data structure not	111	Every C<aio_*> function creates a request. which is a C data structure not
136	directly visible to Perl.	112	directly visible to Perl.
…		…
186		162
187	package IO::AIO;	163	package IO::AIO;
188		164
189	use Carp ();	165	use Carp ();
190		166
191	no warnings;	167	use common::sense;
192	use strict 'vars';
193		168
194	use base 'Exporter';	169	use base 'Exporter';
195		170
196	BEGIN {	171	BEGIN {
197	our $VERSION = '3.23';	172	our $VERSION = 4.34;
198		173
199	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	174	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
200	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	175	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
201	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	176	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
202	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	177	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
		178	aio_pathsync aio_readahead aio_fiemap aio_allocate
203	aio_rename aio_link aio_move aio_copy aio_group	179	aio_rename aio_link aio_move aio_copy aio_group
204	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
205	aio_chmod aio_utime aio_truncate);	181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs
		184	aio_wd);
206		185
207	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209	min_parallel max_parallel max_idle	188	min_parallel max_parallel max_idle idle_timeout
210	nreqs nready npending nthreads	189	nreqs nready npending nthreads
211	max_poll_time max_poll_reqs);	190	max_poll_time max_poll_reqs
		191	sendfile fadvise madvise
		192	mmap munmap munlock munlockall);
212		193
213	push @AIO_REQ, qw(aio_busy); # not exported	194	push @AIO_REQ, qw(aio_busy); # not exported
214		195
215	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	196	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
216		197
…		…
218	XSLoader::load ("IO::AIO", $VERSION);	199	XSLoader::load ("IO::AIO", $VERSION);
219	}	200	}
220		201
221	=head1 FUNCTIONS	202	=head1 FUNCTIONS
222		203
223	=head2 AIO REQUEST FUNCTIONS	204	=head2 QUICK OVERVIEW
		205
		206	This section simply lists the prototypes most of the functions for
		207	quick reference. See the following sections for function-by-function
		208	documentation.
		209
		210	aio_wd $pathname, $callback->($wd)
		211	aio_open $pathname, $flags, $mode, $callback->($fh)
		212	aio_close $fh, $callback->($status)
		213	aio_seek $fh,$offset,$whence, $callback->($offs)
		214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		217	aio_readahead $fh,$offset,$length, $callback->($retval)
		218	aio_stat $fh_or_path, $callback->($status)
		219	aio_lstat $fh, $callback->($status)
		220	aio_statvfs $fh_or_path, $callback->($statvfs)
		221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		223	aio_chmod $fh_or_path, $mode, $callback->($status)
		224	aio_truncate $fh_or_path, $offset, $callback->($status)
		225	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		226	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		227	aio_unlink $pathname, $callback->($status)
		228	aio_mknod $pathname, $mode, $dev, $callback->($status)
		229	aio_link $srcpath, $dstpath, $callback->($status)
		230	aio_symlink $srcpath, $dstpath, $callback->($status)
		231	aio_readlink $pathname, $callback->($link)
		232	aio_realpath $pathname, $callback->($path)
		233	aio_rename $srcpath, $dstpath, $callback->($status)
		234	aio_mkdir $pathname, $mode, $callback->($status)
		235	aio_rmdir $pathname, $callback->($status)
		236	aio_readdir $pathname, $callback->($entries)
		237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		239	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		240	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
		241	aio_load $pathname, $data, $callback->($status)
		242	aio_copy $srcpath, $dstpath, $callback->($status)
		243	aio_move $srcpath, $dstpath, $callback->($status)
		244	aio_rmtree $pathname, $callback->($status)
		245	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		246	aio_ioctl $fh, $request, $buf, $callback->($status)
		247	aio_sync $callback->($status)
		248	aio_syncfs $fh, $callback->($status)
		249	aio_fsync $fh, $callback->($status)
		250	aio_fdatasync $fh, $callback->($status)
		251	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		252	aio_pathsync $pathname, $callback->($status)
		253	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		254	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		255	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		256	aio_mlockall $flags, $callback->($status)
		257	aio_group $callback->(...)
		258	aio_nop $callback->()
		259
		260	$prev_pri = aioreq_pri [$pri]
		261	aioreq_nice $pri_adjust
		262
		263	IO::AIO::poll_wait
		264	IO::AIO::poll_cb
		265	IO::AIO::poll
		266	IO::AIO::flush
		267	IO::AIO::max_poll_reqs $nreqs
		268	IO::AIO::max_poll_time $seconds
		269	IO::AIO::min_parallel $nthreads
		270	IO::AIO::max_parallel $nthreads
		271	IO::AIO::max_idle $nthreads
		272	IO::AIO::idle_timeout $seconds
		273	IO::AIO::max_outstanding $maxreqs
		274	IO::AIO::nreqs
		275	IO::AIO::nready
		276	IO::AIO::npending
		277
		278	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		279	IO::AIO::fadvise $fh, $offset, $len, $advice
		280	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		281	IO::AIO::munmap $scalar
		282	IO::AIO::madvise $scalar, $offset, $length, $advice
		283	IO::AIO::mprotect $scalar, $offset, $length, $protect
		284	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		285	IO::AIO::munlockall
		286
		287	=head2 API NOTES
224		288
225	All the C<aio_*> calls are more or less thin wrappers around the syscall	289	All the C<aio_*> calls are more or less thin wrappers around the syscall
226	with the same name (sans C<aio_>). The arguments are similar or identical,	290	with the same name (sans C<aio_>). The arguments are similar or identical,
227	and they all accept an additional (and optional) C<$callback> argument	291	and they all accept an additional (and optional) C<$callback> argument
228	which must be a code reference. This code reference will get called with	292	which must be a code reference. This code reference will be called after
229	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	293	the syscall has been executed in an asynchronous fashion. The results
230	perl, which usually delivers "false") as its sole argument after the given	294	of the request will be passed as arguments to the callback (and, if an
231	syscall has been executed asynchronously.	295	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		296	most syscalls return C<-1> on error, unlike perl, which usually delivers
		297	"false").
		298
		299	Some requests (such as C<aio_readdir>) pass the actual results and
		300	communicate failures by passing C<undef>.
232		301
233	All functions expecting a filehandle keep a copy of the filehandle	302	All functions expecting a filehandle keep a copy of the filehandle
234	internally until the request has finished.	303	internally until the request has finished.
235		304
236	All functions return request objects of type L<IO::AIO::REQ> that allow	305	All functions return request objects of type L<IO::AIO::REQ> that allow
237	further manipulation of those requests while they are in-flight.	306	further manipulation of those requests while they are in-flight.
238		307
239	The pathnames you pass to these routines I<must> be absolute and	308	The pathnames you pass to these routines I<should> be absolute. The
240	encoded as octets. The reason for the former is that at the time the	309	reason for this is that at the time the request is being executed, the
241	request is being executed, the current working directory could have	310	current working directory could have changed. Alternatively, you can
242	changed. Alternatively, you can make sure that you never change the	311	make sure that you never change the current working directory anywhere
243	current working directory anywhere in the program and then use relative	312	in the program and then use relative paths. You can also take advantage
244	paths.	313	of IO::AIOs working directory abstraction, that lets you specify paths
		314	relative to some previously-opened "working directory object" - see the
		315	description of the C<IO::AIO::WD> class later in this document.
245		316
246	To encode pathnames as octets, either make sure you either: a) always pass	317	To encode pathnames as octets, either make sure you either: a) always pass
247	in filenames you got from outside (command line, readdir etc.) without	318	in filenames you got from outside (command line, readdir etc.) without
248	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	319	tinkering, b) are in your native filesystem encoding, c) use the Encode
249	your pathnames to the locale (or other) encoding in effect in the user	320	module and encode your pathnames to the locale (or other) encoding in
250	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	321	effect in the user environment, d) use Glib::filename_from_unicode on
251	use something else to ensure your scalar has the correct contents.	322	unicode filenames or e) use something else to ensure your scalar has the
		323	correct contents.
252		324
253	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	325	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
254	handles correctly whether it is set or not.	326	handles correctly whether it is set or not.
		327
		328	=head2 AIO REQUEST FUNCTIONS
255		329
256	=over 4	330	=over 4
257		331
258	=item $prev_pri = aioreq_pri [$pri]	332	=item $prev_pri = aioreq_pri [$pri]
259		333
…		…
289		363
290		364
291	=item aio_open $pathname, $flags, $mode, $callback->($fh)	365	=item aio_open $pathname, $flags, $mode, $callback->($fh)
292		366
293	Asynchronously open or create a file and call the callback with a newly	367	Asynchronously open or create a file and call the callback with a newly
294	created filehandle for the file.	368	created filehandle for the file (or C<undef> in case of an error).
295		369
296	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	370	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
297	for an explanation.	371	for an explanation.
298		372
299	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	373	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
306	by the umask in effect then the request is being executed, so better never	380	by the umask in effect then the request is being executed, so better never
307	change the umask.	381	change the umask.
308		382
309	Example:	383	Example:
310		384
311	aio_open "/etc/passwd", O_RDONLY, 0, sub {	385	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
312	if ($_[0]) {	386	if ($_[0]) {
313	print "open successful, fh is $_[0]\n";	387	print "open successful, fh is $_[0]\n";
314	...	388	...
315	} else {	389	} else {
316	die "open failed: $!\n";	390	die "open failed: $!\n";
317	}	391	}
318	};	392	};
319		393
		394	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		395	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		396	following POSIX and non-POSIX constants are available (missing ones on
		397	your system are, as usual, C<0>):
		398
		399	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		400	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		401	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
		402
320		403
321	=item aio_close $fh, $callback->($status)	404	=item aio_close $fh, $callback->($status)
322		405
323	Asynchronously close a file and call the callback with the result	406	Asynchronously close a file and call the callback with the result
324	code.	407	code.
…		…
332		415
333	Or in other words: the file descriptor will be closed, but it will not be	416	Or in other words: the file descriptor will be closed, but it will not be
334	free for reuse until the perl filehandle is closed.	417	free for reuse until the perl filehandle is closed.
335		418
336	=cut	419	=cut
		420
		421	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		422
		423	Seeks the filehandle to the new C<$offset>, similarly to perl's
		424	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		425	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		426	C<IO::AIO::SEEK_END>).
		427
		428	The resulting absolute offset will be passed to the callback, or C<-1> in
		429	case of an error.
		430
		431	In theory, the C<$whence> constants could be different than the
		432	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		433	so don't panic.
		434
		435	As a GNU/Linux (and maybe Solaris) extension, also the constants
		436	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		437	could be found. No guarantees about suitability for use in C<aio_seek> or
		438	Perl's C<sysseek> can be made though, although I would naively assume they
		439	"just work".
337		440
338	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	441	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
339		442
340	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	443	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
341		444
…		…
374		477
375	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	478	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
376	reading at byte offset C<$in_offset>, and starts writing at the current	479	reading at byte offset C<$in_offset>, and starts writing at the current
377	file offset of C<$out_fh>. Because of that, it is not safe to issue more	480	file offset of C<$out_fh>. Because of that, it is not safe to issue more
378	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	481	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
379	other.	482	other. The same C<$in_fh> works fine though, as this function does not
		483	move or use the file offset of C<$in_fh>.
380		484
		485	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		486	are written, and there is no way to find out how many more bytes have been
		487	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		488	number of bytes written to C<$out_fh>. Only if the result value equals
		489	C<$length> one can assume that C<$length> bytes have been read.
		490
		491	Unlike with other C<aio_> functions, it makes a lot of sense to use
		492	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		493	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		494	the socket I/O will be non-blocking. Note, however, that you can run
		495	into a trap where C<aio_sendfile> reads some data with readahead, then
		496	fails to write all data, and when the socket is ready the next time, the
		497	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		498	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		499	resource usage.
		500
381	This call tries to make use of a native C<sendfile> syscall to provide	501	This call tries to make use of a native C<sendfile>-like syscall to
382	zero-copy operation. For this to work, C<$out_fh> should refer to a	502	provide zero-copy operation. For this to work, C<$out_fh> should refer to
383	socket, and C<$in_fh> should refer to mmap'able file.	503	a socket, and C<$in_fh> should refer to an mmap'able file.
384		504
385	If the native sendfile call fails or is not implemented, it will be	505	If a native sendfile cannot be found or it fails with C<ENOSYS>,
386	emulated, so you can call C<aio_sendfile> on any type of filehandle	506	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		507	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
387	regardless of the limitations of the operating system.	508	type of filehandle regardless of the limitations of the operating system.
388		509
389	Please note, however, that C<aio_sendfile> can read more bytes from	510	As native sendfile syscalls (as practically any non-POSIX interface hacked
390	C<$in_fh> than are written, and there is no way to find out how many	511	together in a hurry to improve benchmark numbers) tend to be rather buggy
391	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	512	on many systems, this implementation tries to work around some known bugs
392	provides the number of bytes written to C<$out_fh>. Only if the result	513	in Linux and FreeBSD kernels (probably others, too), but that might fail,
393	value equals C<$length> one can assume that C<$length> bytes have been	514	so you really really should check the return value of C<aio_sendfile> -
394	read.	515	fewre bytes than expected might have been transferred.
395		516
396		517
397	=item aio_readahead $fh,$offset,$length, $callback->($retval)	518	=item aio_readahead $fh,$offset,$length, $callback->($retval)
398		519
399	C<aio_readahead> populates the page cache with data from a file so that	520	C<aio_readahead> populates the page cache with data from a file so that
…		…
422		543
423	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	544	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
424	error when stat'ing a large file, the results will be silently truncated	545	error when stat'ing a large file, the results will be silently truncated
425	unless perl itself is compiled with large file support.	546	unless perl itself is compiled with large file support.
426		547
		548	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		549	following constants and functions (if not implemented, the constants will
		550	be C<0> and the functions will either C<croak> or fall back on traditional
		551	behaviour).
		552
		553	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		554	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		555	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		556
427	Example: Print the length of F</etc/passwd>:	557	Example: Print the length of F</etc/passwd>:
428		558
429	aio_stat "/etc/passwd", sub {	559	aio_stat "/etc/passwd", sub {
430	$_[0] and die "stat failed: $!";	560	$_[0] and die "stat failed: $!";
431	print "size is ", -s _, "\n";	561	print "size is ", -s _, "\n";
432	};	562	};
433		563
434		564
		565	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		566
		567	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		568	whether a file handle or path was passed.
		569
		570	On success, the callback is passed a hash reference with the following
		571	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		572	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		573	is passed.
		574
		575	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		576	C<ST_NOSUID>.
		577
		578	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		579	their correct value when available, or to C<0> on systems that do
		580	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		581	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		582	C<ST_NODIRATIME> and C<ST_RELATIME>.
		583
		584	Example: stat C</wd> and dump out the data if successful.
		585
		586	aio_statvfs "/wd", sub {
		587	my $f = $_[0]
		588	or die "statvfs: $!";
		589
		590	use Data::Dumper;
		591	say Dumper $f;
		592	};
		593
		594	# result:
		595	{
		596	bsize => 1024,
		597	bfree => 4333064312,
		598	blocks => 10253828096,
		599	files => 2050765568,
		600	flag => 4096,
		601	favail => 2042092649,
		602	bavail => 4333064312,
		603	ffree => 2042092649,
		604	namemax => 255,
		605	frsize => 1024,
		606	fsid => 1810
		607	}
		608
		609	Here is a (likely partial - send me updates!) list of fsid values used by
		610	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		611
		612	0x0000adf5 adfs
		613	0x0000adff affs
		614	0x5346414f afs
		615	0x09041934 anon-inode filesystem
		616	0x00000187 autofs
		617	0x42465331 befs
		618	0x1badface bfs
		619	0x42494e4d binfmt_misc
		620	0x9123683e btrfs
		621	0x0027e0eb cgroupfs
		622	0xff534d42 cifs
		623	0x73757245 coda
		624	0x012ff7b7 coh
		625	0x28cd3d45 cramfs
		626	0x453dcd28 cramfs-wend (wrong endianness)
		627	0x64626720 debugfs
		628	0x00001373 devfs
		629	0x00001cd1 devpts
		630	0x0000f15f ecryptfs
		631	0x00414a53 efs
		632	0x0000137d ext
		633	0x0000ef53 ext2/ext3/ext4
		634	0x0000ef51 ext2
		635	0xf2f52010 f2fs
		636	0x00004006 fat
		637	0x65735546 fuseblk
		638	0x65735543 fusectl
		639	0x0bad1dea futexfs
		640	0x01161970 gfs2
		641	0x47504653 gpfs
		642	0x00004244 hfs
		643	0xf995e849 hpfs
		644	0x00c0ffee hostfs
		645	0x958458f6 hugetlbfs
		646	0x2bad1dea inotifyfs
		647	0x00009660 isofs
		648	0x000072b6 jffs2
		649	0x3153464a jfs
		650	0x6b414653 k-afs
		651	0x0bd00bd0 lustre
		652	0x0000137f minix
		653	0x0000138f minix 30 char names
		654	0x00002468 minix v2
		655	0x00002478 minix v2 30 char names
		656	0x00004d5a minix v3
		657	0x19800202 mqueue
		658	0x00004d44 msdos
		659	0x0000564c novell
		660	0x00006969 nfs
		661	0x6e667364 nfsd
		662	0x00003434 nilfs
		663	0x5346544e ntfs
		664	0x00009fa1 openprom
		665	0x7461636F ocfs2
		666	0x00009fa0 proc
		667	0x6165676c pstorefs
		668	0x0000002f qnx4
		669	0x68191122 qnx6
		670	0x858458f6 ramfs
		671	0x52654973 reiserfs
		672	0x00007275 romfs
		673	0x67596969 rpc_pipefs
		674	0x73636673 securityfs
		675	0xf97cff8c selinux
		676	0x0000517b smb
		677	0x534f434b sockfs
		678	0x73717368 squashfs
		679	0x62656572 sysfs
		680	0x012ff7b6 sysv2
		681	0x012ff7b5 sysv4
		682	0x01021994 tmpfs
		683	0x15013346 udf
		684	0x00011954 ufs
		685	0x54190100 ufs byteswapped
		686	0x00009fa2 usbdevfs
		687	0x01021997 v9fs
		688	0xa501fcf5 vxfs
		689	0xabba1974 xenfs
		690	0x012ff7b4 xenix
		691	0x58465342 xfs
		692	0x012fd16d xia
		693
435	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	694	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
436		695
437	Works like perl's C<utime> function (including the special case of $atime	696	Works like perl's C<utime> function (including the special case of $atime
438	and $mtime being undef). Fractional times are supported if the underlying	697	and $mtime being undef). Fractional times are supported if the underlying
439	syscalls support them.	698	syscalls support them.
…		…
466	=item aio_truncate $fh_or_path, $offset, $callback->($status)	725	=item aio_truncate $fh_or_path, $offset, $callback->($status)
467		726
468	Works like truncate(2) or ftruncate(2).	727	Works like truncate(2) or ftruncate(2).
469		728
470		729
		730	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		731
		732	Allocates or frees disk space according to the C<$mode> argument. See the
		733	linux C<fallocate> documentation for details.
		734
		735	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		736	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
		737	to deallocate a file range.
		738
		739	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		740	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		741	your L<fallocate(2)> manpage).
		742
		743	The file system block size used by C<fallocate> is presumably the
		744	C<f_bsize> returned by C<statvfs>.
		745
		746	If C<fallocate> isn't available or cannot be emulated (currently no
		747	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		748
		749
471	=item aio_chmod $fh_or_path, $mode, $callback->($status)	750	=item aio_chmod $fh_or_path, $mode, $callback->($status)
472		751
473	Works like perl's C<chmod> function.	752	Works like perl's C<chmod> function.
474		753
475		754
…		…
477		756
478	Asynchronously unlink (delete) a file and call the callback with the	757	Asynchronously unlink (delete) a file and call the callback with the
479	result code.	758	result code.
480		759
481		760
482	=item aio_mknod $path, $mode, $dev, $callback->($status)	761	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
483		762
484	[EXPERIMENTAL]	763	[EXPERIMENTAL]
485		764
486	Asynchronously create a device node (or fifo). See mknod(2).	765	Asynchronously create a device node (or fifo). See mknod(2).
487		766
488	The only (POSIX-) portable way of calling this function is:	767	The only (POSIX-) portable way of calling this function is:
489		768
490	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	769	aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
491		770
		771	See C<aio_stat> for info about some potentially helpful extra constants
		772	and functions.
492		773
493	=item aio_link $srcpath, $dstpath, $callback->($status)	774	=item aio_link $srcpath, $dstpath, $callback->($status)
494		775
495	Asynchronously create a new link to the existing object at C<$srcpath> at	776	Asynchronously create a new link to the existing object at C<$srcpath> at
496	the path C<$dstpath> and call the callback with the result code.	777	the path C<$dstpath> and call the callback with the result code.
…		…
500		781
501	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	782	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
502	the path C<$dstpath> and call the callback with the result code.	783	the path C<$dstpath> and call the callback with the result code.
503		784
504		785
505	=item aio_readlink $path, $callback->($link)	786	=item aio_readlink $pathname, $callback->($link)
506		787
507	Asynchronously read the symlink specified by C<$path> and pass it to	788	Asynchronously read the symlink specified by C<$path> and pass it to
508	the callback. If an error occurs, nothing or undef gets passed to the	789	the callback. If an error occurs, nothing or undef gets passed to the
509	callback.	790	callback.
510		791
511		792
		793	=item aio_realpath $pathname, $callback->($path)
		794
		795	Asynchronously make the path absolute and resolve any symlinks in
		796	C<$path>. The resulting path only consists of directories (same as
		797	L<Cwd::realpath>).
		798
		799	This request can be used to get the absolute path of the current working
		800	directory by passing it a path of F<.> (a single dot).
		801
		802
512	=item aio_rename $srcpath, $dstpath, $callback->($status)	803	=item aio_rename $srcpath, $dstpath, $callback->($status)
513		804
514	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	805	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
515	rename(2) and call the callback with the result code.	806	rename(2) and call the callback with the result code.
		807
		808	On systems that support the AIO::WD working directory abstraction
		809	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		810	of failing, C<rename> is called on the absolute path of C<$wd>.
516		811
517		812
518	=item aio_mkdir $pathname, $mode, $callback->($status)	813	=item aio_mkdir $pathname, $mode, $callback->($status)
519		814
520	Asynchronously mkdir (create) a directory and call the callback with	815	Asynchronously mkdir (create) a directory and call the callback with
…		…
525	=item aio_rmdir $pathname, $callback->($status)	820	=item aio_rmdir $pathname, $callback->($status)
526		821
527	Asynchronously rmdir (delete) a directory and call the callback with the	822	Asynchronously rmdir (delete) a directory and call the callback with the
528	result code.	823	result code.
529		824
		825	On systems that support the AIO::WD working directory abstraction
		826	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		827	C<rmdir> is called on the absolute path of C<$wd>.
		828
530		829
531	=item aio_readdir $pathname, $callback->($entries)	830	=item aio_readdir $pathname, $callback->($entries)
532		831
533	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	832	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
534	directory (i.e. opendir + readdir + closedir). The entries will not be	833	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
538	array-ref with the filenames.	837	array-ref with the filenames.
539		838
540		839
541	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	840	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
542		841
543	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	842	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
544	behaviour and output format. In case of an error, C<$entries> will be	843	tune behaviour and output format. In case of an error, C<$entries> will be
545	C<undef>.	844	C<undef>.
546		845
547	The flags are a combination of the following constants, ORed together (the	846	The flags are a combination of the following constants, ORed together (the
548	flags will also be passed to the callback, possibly modified):	847	flags will also be passed to the callback, possibly modified):
549		848
550	=over 4	849	=over 4
551		850
552	=item IO::AIO::READDIR_DENTS	851	=item IO::AIO::READDIR_DENTS
553		852
554	When this flag is off, then the callback gets an arrayref with of names	853	When this flag is off, then the callback gets an arrayref consisting of
555	only (as with C<aio_readdir>), otherwise it gets an arrayref with	854	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
556	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	855	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
557	entry in more detail.	856	entry in more detail.
558		857
559	C<$name> is the name of the entry.	858	C<$name> is the name of the entry.
560		859
…		…
573	systems that do not deliver the inode information.	872	systems that do not deliver the inode information.
574		873
575	=item IO::AIO::READDIR_DIRS_FIRST	874	=item IO::AIO::READDIR_DIRS_FIRST
576		875
577	When this flag is set, then the names will be returned in an order where	876	When this flag is set, then the names will be returned in an order where
578	likely directories come first. This is useful when you need to quickly	877	likely directories come first, in optimal stat order. This is useful when
579	find directories, or you want to find all directories while avoiding to	878	you need to quickly find directories, or you want to find all directories
580	stat() each entry.	879	while avoiding to stat() each entry.
581		880
582	If the system returns type information in readdir, then this is used	881	If the system returns type information in readdir, then this is used
583	to find directories directly. Otherwise, likely directories are files	882	to find directories directly. Otherwise, likely directories are names
584	beginning with ".", or otherwise files with no dots, of which files with	883	beginning with ".", or otherwise names with no dots, of which names with
585	short names are tried first.	884	short names are tried first.
586		885
587	=item IO::AIO::READDIR_STAT_ORDER	886	=item IO::AIO::READDIR_STAT_ORDER
588		887
589	When this flag is set, then the names will be returned in an order	888	When this flag is set, then the names will be returned in an order
…		…
596		895
597	=item IO::AIO::READDIR_FOUND_UNKNOWN	896	=item IO::AIO::READDIR_FOUND_UNKNOWN
598		897
599	This flag should not be set when calling C<aio_readdirx>. Instead, it	898	This flag should not be set when calling C<aio_readdirx>. Instead, it
600	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	899	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
601	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	900	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
602	C<$type>'s are known, which can be used to speed up some algorithms.	901	C<$type>'s are known, which can be used to speed up some algorithms.
603		902
604	=back	903	=back
605		904
606		905
607	=item aio_load $path, $data, $callback->($status)	906	=item aio_load $pathname, $data, $callback->($status)
608		907
609	This is a composite request that tries to fully load the given file into	908	This is a composite request that tries to fully load the given file into
610	memory. Status is the same as with aio_read.	909	memory. Status is the same as with aio_read.
611		910
612	=cut	911	=cut
…		…
634		933
635	=item aio_copy $srcpath, $dstpath, $callback->($status)	934	=item aio_copy $srcpath, $dstpath, $callback->($status)
636		935
637	Try to copy the I<file> (directories not supported as either source or	936	Try to copy the I<file> (directories not supported as either source or
638	destination) from C<$srcpath> to C<$dstpath> and call the callback with	937	destination) from C<$srcpath> to C<$dstpath> and call the callback with
639	the C<0> (error) or C<-1> ok.	938	a status of C<0> (ok) or C<-1> (error, see C<$!>).
640		939
641	This is a composite request that creates the destination file with	940	This is a composite request that creates the destination file with
642	mode 0200 and copies the contents of the source file into it using	941	mode 0200 and copies the contents of the source file into it using
643	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	942	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
644	uid/gid, in that order.	943	uid/gid, in that order.
…		…
656	my $grp = aio_group $cb;	955	my $grp = aio_group $cb;
657		956
658	aioreq_pri $pri;	957	aioreq_pri $pri;
659	add $grp aio_open $src, O_RDONLY, 0, sub {	958	add $grp aio_open $src, O_RDONLY, 0, sub {
660	if (my $src_fh = $_[0]) {	959	if (my $src_fh = $_[0]) {
661	my @stat = stat $src_fh; # hmm, might bock over nfs?	960	my @stat = stat $src_fh; # hmm, might block over nfs?
662		961
663	aioreq_pri $pri;	962	aioreq_pri $pri;
664	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	963	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
665	if (my $dst_fh = $_[0]) {	964	if (my $dst_fh = $_[0]) {
666	aioreq_pri $pri;	965	aioreq_pri $pri;
…		…
713		1012
714	=item aio_move $srcpath, $dstpath, $callback->($status)	1013	=item aio_move $srcpath, $dstpath, $callback->($status)
715		1014
716	Try to move the I<file> (directories not supported as either source or	1015	Try to move the I<file> (directories not supported as either source or
717	destination) from C<$srcpath> to C<$dstpath> and call the callback with	1016	destination) from C<$srcpath> to C<$dstpath> and call the callback with
718	the C<0> (error) or C<-1> ok.	1017	a status of C<0> (ok) or C<-1> (error, see C<$!>).
719		1018
720	This is a composite request that tries to rename(2) the file first; if	1019	This is a composite request that tries to rename(2) the file first; if
721	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if	1020	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
722	that is successful, unlinks the C<$srcpath>.	1021	that is successful, unlinks the C<$srcpath>.
723		1022
…		…
734	if ($_[0] && $! == EXDEV) {	1033	if ($_[0] && $! == EXDEV) {
735	aioreq_pri $pri;	1034	aioreq_pri $pri;
736	add $grp aio_copy $src, $dst, sub {	1035	add $grp aio_copy $src, $dst, sub {
737	$grp->result ($_[0]);	1036	$grp->result ($_[0]);
738		1037
739	if (!$_[0]) {	1038	unless ($_[0]) {
740	aioreq_pri $pri;	1039	aioreq_pri $pri;
741	add $grp aio_unlink $src;	1040	add $grp aio_unlink $src;
742	}	1041	}
743	};	1042	};
744	} else {	1043	} else {
…		…
747	};	1046	};
748		1047
749	$grp	1048	$grp
750	}	1049	}
751		1050
752	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1051	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
753		1052
754	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1053	Scans a directory (similar to C<aio_readdir>) but additionally tries to
755	efficiently separate the entries of directory C<$path> into two sets of	1054	efficiently separate the entries of directory C<$path> into two sets of
756	names, directories you can recurse into (directories), and ones you cannot	1055	names, directories you can recurse into (directories), and ones you cannot
757	recurse into (everything else, including symlinks to directories).	1056	recurse into (everything else, including symlinks to directories).
…		…
788	Then entries will be sorted into likely directories a non-initial dot	1087	Then entries will be sorted into likely directories a non-initial dot
789	currently) and likely non-directories (see C<aio_readdirx>). Then every	1088	currently) and likely non-directories (see C<aio_readdirx>). Then every
790	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1089	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
791	in order of their inode numbers. If that succeeds, it assumes that the	1090	in order of their inode numbers. If that succeeds, it assumes that the
792	entry is a directory or a symlink to directory (which will be checked	1091	entry is a directory or a symlink to directory (which will be checked
793	seperately). This is often faster than stat'ing the entry itself because	1092	separately). This is often faster than stat'ing the entry itself because
794	filesystems might detect the type of the entry without reading the inode	1093	filesystems might detect the type of the entry without reading the inode
795	data (e.g. ext2fs filetype feature), even on systems that cannot return	1094	data (e.g. ext2fs filetype feature), even on systems that cannot return
796	the filetype information on readdir.	1095	the filetype information on readdir.
797		1096
798	If the known number of directories (link count - 2) has been reached, the	1097	If the known number of directories (link count - 2) has been reached, the
…		…
814		1113
815	my $grp = aio_group $cb;	1114	my $grp = aio_group $cb;
816		1115
817	$maxreq = 4 if $maxreq <= 0;	1116	$maxreq = 4 if $maxreq <= 0;
818		1117
819	# stat once	1118	# get a wd object
820	aioreq_pri $pri;	1119	aioreq_pri $pri;
821	add $grp aio_stat $path, sub {	1120	add $grp aio_wd $path, sub {
		1121	$_[0]
822	return $grp->result () if $_[0];	1122	or return $grp->result ();
823	my $now = time;
824	my $hash1 = join ":", (stat _)[0,1,3,7,9];
825		1123
826	# read the directory entries	1124	my $wd = [shift, "."];
		1125
		1126	# stat once
827	aioreq_pri $pri;	1127	aioreq_pri $pri;
828	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1128	add $grp aio_stat $wd, sub {
829	my $entries = shift
830	or return $grp->result ();	1129	return $grp->result () if $_[0];
		1130	my $now = time;
		1131	my $hash1 = join ":", (stat _)[0,1,3,7,9];
831		1132
832	# stat the dir another time	1133	# read the directory entries
833	aioreq_pri $pri;	1134	aioreq_pri $pri;
		1135	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1136	my $entries = shift
		1137	or return $grp->result ();
		1138
		1139	# stat the dir another time
		1140	aioreq_pri $pri;
834	add $grp aio_stat $path, sub {	1141	add $grp aio_stat $wd, sub {
835	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1142	my $hash2 = join ":", (stat _)[0,1,3,7,9];
836		1143
837	my $ndirs;	1144	my $ndirs;
838		1145
839	# take the slow route if anything looks fishy	1146	# take the slow route if anything looks fishy
840	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1147	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
841	$ndirs = -1;	1148	$ndirs = -1;
842	} else {	1149	} else {
843	# if nlink == 2, we are finished	1150	# if nlink == 2, we are finished
844	# for non-posix-fs's, we rely on nlink < 2	1151	# for non-posix-fs's, we rely on nlink < 2
845	$ndirs = (stat _)[3] - 2	1152	$ndirs = (stat _)[3] - 2
846	or return $grp->result ([], $entries);	1153	or return $grp->result ([], $entries);
847	}	1154	}
848		1155
849	my (@dirs, @nondirs);	1156	my (@dirs, @nondirs);
850		1157
851	my $statgrp = add $grp aio_group sub {	1158	my $statgrp = add $grp aio_group sub {
852	$grp->result (\@dirs, \@nondirs);	1159	$grp->result (\@dirs, \@nondirs);
853	};	1160	};
854		1161
855	limit $statgrp $maxreq;	1162	limit $statgrp $maxreq;
856	feed $statgrp sub {	1163	feed $statgrp sub {
857	return unless @$entries;	1164	return unless @$entries;
858	my $entry = shift @$entries;	1165	my $entry = shift @$entries;
859		1166
860	aioreq_pri $pri;	1167	aioreq_pri $pri;
		1168	$wd->[1] = "$entry/.";
861	add $statgrp aio_stat "$path/$entry/.", sub {	1169	add $statgrp aio_stat $wd, sub {
862	if ($_[0] < 0) {	1170	if ($_[0] < 0) {
863	push @nondirs, $entry;	1171	push @nondirs, $entry;
864	} else {	1172	} else {
865	# need to check for real directory	1173	# need to check for real directory
866	aioreq_pri $pri;	1174	aioreq_pri $pri;
		1175	$wd->[1] = $entry;
867	add $statgrp aio_lstat "$path/$entry", sub {	1176	add $statgrp aio_lstat $wd, sub {
868	if (-d _) {	1177	if (-d _) {
869	push @dirs, $entry;	1178	push @dirs, $entry;
870		1179
871	unless (--$ndirs) {	1180	unless (--$ndirs) {
872	push @nondirs, @$entries;	1181	push @nondirs, @$entries;
873	feed $statgrp;	1182	feed $statgrp;
		1183	}
		1184	} else {
		1185	push @nondirs, $entry;
874	}	1186	}
875	} else {
876	push @nondirs, $entry;
877	}	1187	}
878	}	1188	}
879	}	1189	};
880	};	1190	};
881	};	1191	};
882	};	1192	};
883	};	1193	};
884	};	1194	};
885		1195
886	$grp	1196	$grp
887	}	1197	}
888		1198
889	=item aio_rmtree $path, $callback->($status)	1199	=item aio_rmtree $pathname, $callback->($status)
890		1200
891	Delete a directory tree starting (and including) C<$path>, return the	1201	Delete a directory tree starting (and including) C<$path>, return the
892	status of the final C<rmdir> only. This is a composite request that	1202	status of the final C<rmdir> only. This is a composite request that
893	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1203	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
894	everything else.	1204	everything else.
895		1205
896	=cut	1206	=cut
897		1207
…		…
919	};	1229	};
920		1230
921	$grp	1231	$grp
922	}	1232	}
923		1233
		1234	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1235
		1236	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1237
		1238	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1239	they execute asynchronously and pass the return value to the callback.
		1240
		1241	Both calls can be used for a lot of things, some of which make more sense
		1242	to run asynchronously in their own thread, while some others make less
		1243	sense. For example, calls that block waiting for external events, such
		1244	as locking, will also lock down an I/O thread while it is waiting, which
		1245	can deadlock the whole I/O system. At the same time, there might be no
		1246	alternative to using a thread to wait.
		1247
		1248	So in general, you should only use these calls for things that do
		1249	(filesystem) I/O, not for things that wait for other events (network,
		1250	other processes), although if you are careful and know what you are doing,
		1251	you still can.
		1252
924	=item aio_sync $callback->($status)	1253	=item aio_sync $callback->($status)
925		1254
926	Asynchronously call sync and call the callback when finished.	1255	Asynchronously call sync and call the callback when finished.
927		1256
928	=item aio_fsync $fh, $callback->($status)	1257	=item aio_fsync $fh, $callback->($status)
…		…
935	Asynchronously call fdatasync on the given filehandle and call the	1264	Asynchronously call fdatasync on the given filehandle and call the
936	callback with the fdatasync result code.	1265	callback with the fdatasync result code.
937		1266
938	If this call isn't available because your OS lacks it or it couldn't be	1267	If this call isn't available because your OS lacks it or it couldn't be
939	detected, it will be emulated by calling C<fsync> instead.	1268	detected, it will be emulated by calling C<fsync> instead.
		1269
		1270	=item aio_syncfs $fh, $callback->($status)
		1271
		1272	Asynchronously call the syncfs syscall to sync the filesystem associated
		1273	to the given filehandle and call the callback with the syncfs result
		1274	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1275	errno to C<ENOSYS> nevertheless.
940		1276
941	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1277	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
942		1278
943	Sync the data portion of the file specified by C<$offset> and C<$length>	1279	Sync the data portion of the file specified by C<$offset> and C<$length>
944	to disk (but NOT the metadata), by calling the Linux-specific	1280	to disk (but NOT the metadata), by calling the Linux-specific
…		…
948	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1284	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
949	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1285	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
950	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1286	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
951	manpage for details.	1287	manpage for details.
952		1288
953	=item aio_pathsync $path, $callback->($status)	1289	=item aio_pathsync $pathname, $callback->($status)
954		1290
955	This request tries to open, fsync and close the given path. This is a	1291	This request tries to open, fsync and close the given path. This is a
956	composite request intended to sync directories after directory operations	1292	composite request intended to sync directories after directory operations
957	(E.g. rename). This might not work on all operating systems or have any	1293	(E.g. rename). This might not work on all operating systems or have any
958	specific effect, but usually it makes sure that directory changes get	1294	specific effect, but usually it makes sure that directory changes get
959	written to disc. It works for anything that can be opened for read-only,	1295	written to disc. It works for anything that can be opened for read-only,
960	not just directories.	1296	not just directories.
		1297
		1298	Future versions of this function might fall back to other methods when
		1299	C<fsync> on the directory fails (such as calling C<sync>).
961		1300
962	Passes C<0> when everything went ok, and C<-1> on error.	1301	Passes C<0> when everything went ok, and C<-1> on error.
963		1302
964	=cut	1303	=cut
965		1304
…		…
986	};	1325	};
987		1326
988	$grp	1327	$grp
989	}	1328	}
990		1329
		1330	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1331
		1332	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1333	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1334	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1335	scalar must only be modified in-place while an aio operation is pending on
		1336	it).
		1337
		1338	It calls the C<msync> function of your OS, if available, with the memory
		1339	area starting at C<$offset> in the string and ending C<$length> bytes
		1340	later. If C<$length> is negative, counts from the end, and if C<$length>
		1341	is C<undef>, then it goes till the end of the string. The flags can be
		1342	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1343	C<IO::AIO::MS_SYNC>.
		1344
		1345	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1346
		1347	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1348	scalars.
		1349
		1350	It touches (reads or writes) all memory pages in the specified
		1351	range inside the scalar. All caveats and parameters are the same
		1352	as for C<aio_msync>, above, except for flags, which must be either
		1353	C<0> (which reads all pages and ensures they are instantiated) or
		1354	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
		1355	writing an octet from it, which dirties the page).
		1356
		1357	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1358
		1359	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1360	scalars.
		1361
		1362	It reads in all the pages of the underlying storage into memory (if any)
		1363	and locks them, so they are not getting swapped/paged out or removed.
		1364
		1365	If C<$length> is undefined, then the scalar will be locked till the end.
		1366
		1367	On systems that do not implement C<mlock>, this function returns C<-1>
		1368	and sets errno to C<ENOSYS>.
		1369
		1370	Note that the corresponding C<munlock> is synchronous and is
		1371	documented under L<MISCELLANEOUS FUNCTIONS>.
		1372
		1373	Example: open a file, mmap and mlock it - both will be undone when
		1374	C<$data> gets destroyed.
		1375
		1376	open my $fh, "<", $path or die "$path: $!";
		1377	my $data;
		1378	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1379	aio_mlock $data; # mlock in background
		1380
		1381	=item aio_mlockall $flags, $callback->($status)
		1382
		1383	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1384	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1385
		1386	On systems that do not implement C<mlockall>, this function returns C<-1>
		1387	and sets errno to C<ENOSYS>.
		1388
		1389	Note that the corresponding C<munlockall> is synchronous and is
		1390	documented under L<MISCELLANEOUS FUNCTIONS>.
		1391
		1392	Example: asynchronously lock all current and future pages into memory.
		1393
		1394	aio_mlockall IO::AIO::MCL_FUTURE;
		1395
		1396	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1397
		1398	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1399	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1400	the ioctl is not available on your OS, then this request will fail with
		1401	C<ENOSYS>.
		1402
		1403	C<$start> is the starting offset to query extents for, C<$length> is the
		1404	size of the range to query - if it is C<undef>, then the whole file will
		1405	be queried.
		1406
		1407	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1408	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1409	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1410	the data portion.
		1411
		1412	C<$count> is the maximum number of extent records to return. If it is
		1413	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1414	case, if it is C<0>, then the callback receives the number of extents
		1415	instead of the extents themselves (which is unreliable, see below).
		1416
		1417	If an error occurs, the callback receives no arguments. The special
		1418	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1419
		1420	Otherwise, the callback receives an array reference with extent
		1421	structures. Each extent structure is an array reference itself, with the
		1422	following members:
		1423
		1424	[$logical, $physical, $length, $flags]
		1425
		1426	Flags is any combination of the following flag values (typically either C<0>
		1427	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1428
		1429	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1430	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1431	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1432	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1433	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1434	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1435
		1436	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1437	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1438	it to return all extents of a range for files with large number of
		1439	extents. The code works around all these issues if C<$count> is undef.
		1440
991	=item aio_group $callback->(...)	1441	=item aio_group $callback->(...)
992		1442
993	This is a very special aio request: Instead of doing something, it is a	1443	This is a very special aio request: Instead of doing something, it is a
994	container for other aio requests, which is useful if you want to bundle	1444	container for other aio requests, which is useful if you want to bundle
995	many requests into a single, composite, request with a definite callback	1445	many requests into a single, composite, request with a definite callback
…		…
1031	like sleep and file handle readable/writable, the overhead this creates is	1481	like sleep and file handle readable/writable, the overhead this creates is
1032	immense (it blocks a thread for a long time) so do not use this function	1482	immense (it blocks a thread for a long time) so do not use this function
1033	except to put your application under artificial I/O pressure.	1483	except to put your application under artificial I/O pressure.
1034		1484
1035	=back	1485	=back
		1486
		1487
		1488	=head2 IO::AIO::WD - multiple working directories
		1489
		1490	Your process only has one current working directory, which is used by all
		1491	threads. This makes it hard to use relative paths (some other component
		1492	could call C<chdir> at any time, and it is hard to control when the path
		1493	will be used by IO::AIO).
		1494
		1495	One solution for this is to always use absolute paths. This usually works,
		1496	but can be quite slow (the kernel has to walk the whole path on every
		1497	access), and can also be a hassle to implement.
		1498
		1499	Newer POSIX systems have a number of functions (openat, fdopendir,
		1500	futimensat and so on) that make it possible to specify working directories
		1501	per operation.
		1502
		1503	For portability, and because the clowns who "designed", or shall I write,
		1504	perpetrated this new interface were obviously half-drunk, this abstraction
		1505	cannot be perfect, though.
		1506
		1507	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1508	object. This object stores the canonicalised, absolute version of the
		1509	path, and on systems that allow it, also a directory file descriptor.
		1510
		1511	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1512	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1513	object and a pathname instead (or the IO::AIO::WD object alone, which
		1514	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1515	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1516	to that IO::AIO::WD object.
		1517
		1518	For example, to get a wd object for F</etc> and then stat F<passwd>
		1519	inside, you would write:
		1520
		1521	aio_wd "/etc", sub {
		1522	my $etcdir = shift;
		1523
		1524	# although $etcdir can be undef on error, there is generally no reason
		1525	# to check for errors here, as aio_stat will fail with ENOENT
		1526	# when $etcdir is undef.
		1527
		1528	aio_stat [$etcdir, "passwd"], sub {
		1529	# yay
		1530	};
		1531	};
		1532
		1533	The fact that C<aio_wd> is a request and not a normal function shows that
		1534	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1535	which is why it is done asynchronously.
		1536
		1537	To stat the directory obtained with C<aio_wd> above, one could write
		1538	either of the following three request calls:
		1539
		1540	aio_lstat "/etc" , sub { ... # pathname as normal string
		1541	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1542	aio_lstat $wd , sub { ... # shorthand for the previous
		1543
		1544	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1545	object and the pathname string, so you could write the following without
		1546	causing any issues due to C<$path> getting reused:
		1547
		1548	my $path = [$wd, undef];
		1549
		1550	for my $name (qw(abc def ghi)) {
		1551	$path->[1] = $name;
		1552	aio_stat $path, sub {
		1553	# ...
		1554	};
		1555	}
		1556
		1557	There are some caveats: when directories get renamed (or deleted), the
		1558	pathname string doesn't change, so will point to the new directory (or
		1559	nowhere at all), while the directory fd, if available on the system,
		1560	will still point to the original directory. Most functions accepting a
		1561	pathname will use the directory fd on newer systems, and the string on
		1562	older systems. Some functions (such as realpath) will always rely on the
		1563	string form of the pathname.
		1564
		1565	So this functionality is mainly useful to get some protection against
		1566	C<chdir>, to easily get an absolute path out of a relative path for future
		1567	reference, and to speed up doing many operations in the same directory
		1568	(e.g. when stat'ing all files in a directory).
		1569
		1570	The following functions implement this working directory abstraction:
		1571
		1572	=over 4
		1573
		1574	=item aio_wd $pathname, $callback->($wd)
		1575
		1576	Asynchonously canonicalise the given pathname and convert it to an
		1577	IO::AIO::WD object representing it. If possible and supported on the
		1578	system, also open a directory fd to speed up pathname resolution relative
		1579	to this working directory.
		1580
		1581	If something goes wrong, then C<undef> is passwd to the callback instead
		1582	of a working directory object and C<$!> is set appropriately. Since
		1583	passing C<undef> as working directory component of a pathname fails the
		1584	request with C<ENOENT>, there is often no need for error checking in the
		1585	C<aio_wd> callback, as future requests using the value will fail in the
		1586	expected way.
		1587
		1588	=item IO::AIO::CWD
		1589
		1590	This is a compiletime constant (object) that represents the process
		1591	current working directory.
		1592
		1593	Specifying this object as working directory object for a pathname is as if
		1594	the pathname would be specified directly, without a directory object. For
		1595	example, these calls are functionally identical:
		1596
		1597	aio_stat "somefile", sub { ... };
		1598	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1599
		1600	=back
		1601
		1602	To recover the path associated with an IO::AIO::WD object, you can use
		1603	C<aio_realpath>:
		1604
		1605	aio_realpath $wd, sub {
		1606	warn "path is $_[0]\n";
		1607	};
		1608
		1609	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1610	sometimes, fall back to using an absolue path.
1036		1611
1037	=head2 IO::AIO::REQ CLASS	1612	=head2 IO::AIO::REQ CLASS
1038		1613
1039	All non-aggregate C<aio_*> functions return an object of this class when	1614	All non-aggregate C<aio_*> functions return an object of this class when
1040	called in non-void context.	1615	called in non-void context.
…		…
1130	=item $grp->cancel_subs	1705	=item $grp->cancel_subs
1131		1706
1132	Cancel all subrequests and clears any feeder, but not the group request	1707	Cancel all subrequests and clears any feeder, but not the group request
1133	itself. Useful when you queued a lot of events but got a result early.	1708	itself. Useful when you queued a lot of events but got a result early.
1134		1709
		1710	The group request will finish normally (you cannot add requests to the
		1711	group).
		1712
1135	=item $grp->result (...)	1713	=item $grp->result (...)
1136		1714
1137	Set the result value(s) that will be passed to the group callback when all	1715	Set the result value(s) that will be passed to the group callback when all
1138	subrequests have finished and set the groups errno to the current value	1716	subrequests have finished and set the groups errno to the current value
1139	of errno (just like calling C<errno> without an error number). By default,	1717	of errno (just like calling C<errno> without an error number). By default,
…		…
1155		1733
1156	Sets a feeder/generator on this group: every group can have an attached	1734	Sets a feeder/generator on this group: every group can have an attached
1157	generator that generates requests if idle. The idea behind this is that,	1735	generator that generates requests if idle. The idea behind this is that,
1158	although you could just queue as many requests as you want in a group,	1736	although you could just queue as many requests as you want in a group,
1159	this might starve other requests for a potentially long time. For example,	1737	this might starve other requests for a potentially long time. For example,
1160	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1738	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1161	delaying any later requests for a long time.	1739	requests, delaying any later requests for a long time.
1162		1740
1163	To avoid this, and allow incremental generation of requests, you can	1741	To avoid this, and allow incremental generation of requests, you can
1164	instead a group and set a feeder on it that generates those requests. The	1742	instead a group and set a feeder on it that generates those requests. The
1165	feed callback will be called whenever there are few enough (see C<limit>,	1743	feed callback will be called whenever there are few enough (see C<limit>,
1166	below) requests active in the group itself and is expected to queue more	1744	below) requests active in the group itself and is expected to queue more
…		…
1215		1793
1216	See C<poll_cb> for an example.	1794	See C<poll_cb> for an example.
1217		1795
1218	=item IO::AIO::poll_cb	1796	=item IO::AIO::poll_cb
1219		1797
1220	Process some outstanding events on the result pipe. You have to call this	1798	Process some requests that have reached the result phase (i.e. they have
1221	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1799	been executed but the results are not yet reported). You have to call
1222	returned earlier for whatever reason. Returns immediately when no events	1800	this "regularly" to finish outstanding requests.
1223	are outstanding. The amount of events processed depends on the settings of
1224	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1225		1801
		1802	Returns C<0> if all events could be processed (or there were no
		1803	events to process), or C<-1> if it returned earlier for whatever
		1804	reason. Returns immediately when no events are outstanding. The amount
		1805	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
		1806	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
		1807
1226	If not all requests were processed for whatever reason, the filehandle	1808	If not all requests were processed for whatever reason, the poll file
1227	will still be ready when C<poll_cb> returns, so normally you don't have to	1809	descriptor will still be ready when C<poll_cb> returns, so normally you
1228	do anything special to have it called later.	1810	don't have to do anything special to have it called later.
		1811
		1812	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1813	ready, it can be beneficial to call this function from loops which submit
		1814	a lot of requests, to make sure the results get processed when they become
		1815	available and not just when the loop is finished and the event loop takes
		1816	over again. This function returns very fast when there are no outstanding
		1817	requests.
1229		1818
1230	Example: Install an Event watcher that automatically calls	1819	Example: Install an Event watcher that automatically calls
1231	IO::AIO::poll_cb with high priority (more examples can be found in the	1820	IO::AIO::poll_cb with high priority (more examples can be found in the
1232	SYNOPSIS section, at the top of this document):	1821	SYNOPSIS section, at the top of this document):
1233		1822
1234	Event->io (fd => IO::AIO::poll_fileno,	1823	Event->io (fd => IO::AIO::poll_fileno,
1235	poll => 'r', async => 1,	1824	poll => 'r', async => 1,
1236	cb => \&IO::AIO::poll_cb);	1825	cb => \&IO::AIO::poll_cb);
		1826
		1827	=item IO::AIO::poll_wait
		1828
		1829	Wait until either at least one request is in the result phase or no
		1830	requests are outstanding anymore.
		1831
		1832	This is useful if you want to synchronously wait for some requests to
		1833	become ready, without actually handling them.
		1834
		1835	See C<nreqs> for an example.
		1836
		1837	=item IO::AIO::poll
		1838
		1839	Waits until some requests have been handled.
		1840
		1841	Returns the number of requests processed, but is otherwise strictly
		1842	equivalent to:
		1843
		1844	IO::AIO::poll_wait, IO::AIO::poll_cb
		1845
		1846	=item IO::AIO::flush
		1847
		1848	Wait till all outstanding AIO requests have been handled.
		1849
		1850	Strictly equivalent to:
		1851
		1852	IO::AIO::poll_wait, IO::AIO::poll_cb
		1853	while IO::AIO::nreqs;
1237		1854
1238	=item IO::AIO::max_poll_reqs $nreqs	1855	=item IO::AIO::max_poll_reqs $nreqs
1239		1856
1240	=item IO::AIO::max_poll_time $seconds	1857	=item IO::AIO::max_poll_time $seconds
1241		1858
…		…
1266	# use a low priority so other tasks have priority	1883	# use a low priority so other tasks have priority
1267	Event->io (fd => IO::AIO::poll_fileno,	1884	Event->io (fd => IO::AIO::poll_fileno,
1268	poll => 'r', nice => 1,	1885	poll => 'r', nice => 1,
1269	cb => &IO::AIO::poll_cb);	1886	cb => &IO::AIO::poll_cb);
1270		1887
1271	=item IO::AIO::poll_wait
1272
1273	If there are any outstanding requests and none of them in the result
1274	phase, wait till the result filehandle becomes ready for reading (simply
1275	does a C<select> on the filehandle. This is useful if you want to
1276	synchronously wait for some requests to finish).
1277
1278	See C<nreqs> for an example.
1279
1280	=item IO::AIO::poll
1281
1282	Waits until some requests have been handled.
1283
1284	Returns the number of requests processed, but is otherwise strictly
1285	equivalent to:
1286
1287	IO::AIO::poll_wait, IO::AIO::poll_cb
1288
1289	=item IO::AIO::flush
1290
1291	Wait till all outstanding AIO requests have been handled.
1292
1293	Strictly equivalent to:
1294
1295	IO::AIO::poll_wait, IO::AIO::poll_cb
1296	while IO::AIO::nreqs;
1297
1298	=back	1888	=back
1299		1889
1300	=head3 CONTROLLING THE NUMBER OF THREADS	1890	=head3 CONTROLLING THE NUMBER OF THREADS
1301		1891
1302	=over	1892	=over
…		…
1335		1925
1336	Under normal circumstances you don't need to call this function.	1926	Under normal circumstances you don't need to call this function.
1337		1927
1338	=item IO::AIO::max_idle $nthreads	1928	=item IO::AIO::max_idle $nthreads
1339		1929
1340	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1930	Limit the number of threads (default: 4) that are allowed to idle
1341	threads that did not get a request to process within 10 seconds). That	1931	(i.e., threads that did not get a request to process within the idle
1342	means if a thread becomes idle while C<$nthreads> other threads are also	1932	timeout (default: 10 seconds). That means if a thread becomes idle while
1343	idle, it will free its resources and exit.	1933	C<$nthreads> other threads are also idle, it will free its resources and
		1934	exit.
1344		1935
1345	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1936	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1346	to allow for extremely high load situations, but want to free resources	1937	to allow for extremely high load situations, but want to free resources
1347	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1938	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1348		1939
1349	The default is probably ok in most situations, especially if thread	1940	The default is probably ok in most situations, especially if thread
1350	creation is fast. If thread creation is very slow on your system you might	1941	creation is fast. If thread creation is very slow on your system you might
1351	want to use larger values.	1942	want to use larger values.
1352		1943
		1944	=item IO::AIO::idle_timeout $seconds
		1945
		1946	Sets the minimum idle timeout (default 10) after which worker threads are
		1947	allowed to exit. SEe C<IO::AIO::max_idle>.
		1948
1353	=item IO::AIO::max_outstanding $maxreqs	1949	=item IO::AIO::max_outstanding $maxreqs
		1950
		1951	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1952	you do queue up more than this number of requests, the next call to
		1953	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1954	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1955	longer exceeded.
		1956
		1957	In other words, this setting does not enforce a queue limit, but can be
		1958	used to make poll functions block if the limit is exceeded.
1354		1959
1355	This is a very bad function to use in interactive programs because it	1960	This is a very bad function to use in interactive programs because it
1356	blocks, and a bad way to reduce concurrency because it is inexact: Better	1961	blocks, and a bad way to reduce concurrency because it is inexact: Better
1357	use an C<aio_group> together with a feed callback.	1962	use an C<aio_group> together with a feed callback.
1358		1963
1359	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1964	Its main use is in scripts without an event loop - when you want to stat
1360	do queue up more than this number of requests, the next call to the	1965	a lot of files, you can write somehting like this:
1361	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1362	function will block until the limit is no longer exceeded.
1363		1966
1364	The default value is very large, so there is no practical limit on the	1967	IO::AIO::max_outstanding 32;
1365	number of outstanding requests.
1366		1968
1367	You can still queue as many requests as you want. Therefore,	1969	for my $path (...) {
1368	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1970	aio_stat $path , ...;
1369	as a stop gap to shield against fatal memory overflow (with large values).	1971	IO::AIO::poll_cb;
		1972	}
		1973
		1974	IO::AIO::flush;
		1975
		1976	The call to C<poll_cb> inside the loop will normally return instantly, but
		1977	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1978	some requests have been handled. This keeps the loop from pushing a large
		1979	number of C<aio_stat> requests onto the queue.
		1980
		1981	The default value for C<max_outstanding> is very large, so there is no
		1982	practical limit on the number of outstanding requests.
1370		1983
1371	=back	1984	=back
1372		1985
1373	=head3 STATISTICAL INFORMATION	1986	=head3 STATISTICAL INFORMATION
1374		1987
…		…
1394	Returns the number of requests currently in the pending state (executed,	2007	Returns the number of requests currently in the pending state (executed,
1395	but not yet processed by poll_cb).	2008	but not yet processed by poll_cb).
1396		2009
1397	=back	2010	=back
1398		2011
		2012	=head3 MISCELLANEOUS FUNCTIONS
		2013
		2014	IO::AIO implements some functions that are useful when you want to use
		2015	some "Advanced I/O" function not available to in Perl, without going the
		2016	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2017	counterpart.
		2018
		2019	=over 4
		2020
		2021	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		2022
		2023	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		2024	but is blocking (this makes most sense if you know the input data is
		2025	likely cached already and the output filehandle is set to non-blocking
		2026	operations).
		2027
		2028	Returns the number of bytes copied, or C<-1> on error.
		2029
		2030	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		2031
		2032	Simply calls the C<posix_fadvise> function (see its
		2033	manpage for details). The following advice constants are
		2034	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		2035	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		2036	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		2037
		2038	On systems that do not implement C<posix_fadvise>, this function returns
		2039	ENOSYS, otherwise the return value of C<posix_fadvise>.
		2040
		2041	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		2042
		2043	Simply calls the C<posix_madvise> function (see its
		2044	manpage for details). The following advice constants are
		2045	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		2046	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		2047
		2048	On systems that do not implement C<posix_madvise>, this function returns
		2049	ENOSYS, otherwise the return value of C<posix_madvise>.
		2050
		2051	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		2052
		2053	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		2054	$scalar (see its manpage for details). The following protect
		2055	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		2056	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		2057
		2058	On systems that do not implement C<mprotect>, this function returns
		2059	ENOSYS, otherwise the return value of C<mprotect>.
		2060
		2061	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		2062
		2063	Memory-maps a file (or anonymous memory range) and attaches it to the
		2064	given C<$scalar>, which will act like a string scalar. Returns true on
		2065	success, and false otherwise.
		2066
		2067	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		2068	change the string length, and most read-only operations such as copying it
		2069	or searching it with regexes and so on.
		2070
		2071	Anything else is unsafe and will, at best, result in memory leaks.
		2072
		2073	The memory map associated with the C<$scalar> is automatically removed
		2074	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		2075	C<IO::AIO::munmap> functions are called.
		2076
		2077	This calls the C<mmap>(2) function internally. See your system's manual
		2078	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		2079
		2080	The C<$length> must be larger than zero and smaller than the actual
		2081	filesize.
		2082
		2083	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		2084	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		2085
		2086	C<$flags> can be a combination of
		2087	C<IO::AIO::MAP_SHARED> or
		2088	C<IO::AIO::MAP_PRIVATE>,
		2089	or a number of system-specific flags (when not available, the are C<0>):
		2090	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
		2091	C<IO::AIO::MAP_LOCKED>,
		2092	C<IO::AIO::MAP_NORESERVE>,
		2093	C<IO::AIO::MAP_POPULATE>,
		2094	C<IO::AIO::MAP_NONBLOCK>,
		2095	C<IO::AIO::MAP_FIXED>,
		2096	C<IO::AIO::MAP_GROWSDOWN>,
		2097	C<IO::AIO::MAP_32BIT>,
		2098	C<IO::AIO::MAP_HUGETLB> or
		2099	C<IO::AIO::MAP_STACK>.
		2100
		2101	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		2102
		2103	C<$offset> is the offset from the start of the file - it generally must be
		2104	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		2105
		2106	Example:
		2107
		2108	use Digest::MD5;
		2109	use IO::AIO;
		2110
		2111	open my $fh, "<verybigfile"
		2112	or die "$!";
		2113
		2114	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		2115	or die "verybigfile: $!";
		2116
		2117	my $fast_md5 = md5 $data;
		2118
		2119	=item IO::AIO::munmap $scalar
		2120
		2121	Removes a previous mmap and undefines the C<$scalar>.
		2122
		2123	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		2124
		2125	Calls the C<munlock> function, undoing the effects of a previous
		2126	C<aio_mlock> call (see its description for details).
		2127
		2128	=item IO::AIO::munlockall
		2129
		2130	Calls the C<munlockall> function.
		2131
		2132	On systems that do not implement C<munlockall>, this function returns
		2133	ENOSYS, otherwise the return value of C<munlockall>.
		2134
		2135	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2136
		2137	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2138	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2139	should be the file offset.
		2140
		2141	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2142	silently corrupt the data in this case.
		2143
		2144	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2145	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2146	C<IO::AIO::SPLICE_F_GIFT>.
		2147
		2148	See the C<splice(2)> manpage for details.
		2149
		2150	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2151
		2152	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2153	description for C<IO::AIO::splice> above for details.
		2154
		2155	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2156
		2157	Attempts to query or change the pipe buffer size. Obviously works only
		2158	on pipes, and currently works only on GNU/Linux systems, and fails with
		2159	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2160	size on other systems, drop me a note.
		2161
		2162	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2163
		2164	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2165	C<$flags> is missing or C<0>, then this should be the same as a call to
		2166	perl's built-in C<pipe> function and create a new pipe, and works on
		2167	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2168	(..., 4096, O_BINARY)>.
		2169
		2170	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2171	the given flags (Linux 2.6.27, glibc 2.9).
		2172
		2173	On success, the read and write file handles are returned.
		2174
		2175	On error, nothing will be returned. If the pipe2 syscall is missing and
		2176	C<$flags> is non-zero, fails with C<ENOSYS>.
		2177
		2178	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2179	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2180	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2181
		2182	=back
		2183
1399	=cut	2184	=cut
1400		2185
1401	min_parallel 8;	2186	min_parallel 8;
1402		2187
1403	END { flush }	2188	END { flush }
1404		2189
1405	1;	2190	1;
1406		2191
		2192	=head1 EVENT LOOP INTEGRATION
		2193
		2194	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		2195	automatically into many event loops:
		2196
		2197	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		2198	use AnyEvent::AIO;
		2199
		2200	You can also integrate IO::AIO manually into many event loops, here are
		2201	some examples of how to do this:
		2202
		2203	# EV integration
		2204	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		2205
		2206	# Event integration
		2207	Event->io (fd => IO::AIO::poll_fileno,
		2208	poll => 'r',
		2209	cb => \&IO::AIO::poll_cb);
		2210
		2211	# Glib/Gtk2 integration
		2212	add_watch Glib::IO IO::AIO::poll_fileno,
		2213	in => sub { IO::AIO::poll_cb; 1 };
		2214
		2215	# Tk integration
		2216	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		2217	readable => \&IO::AIO::poll_cb);
		2218
		2219	# Danga::Socket integration
		2220	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		2221	\&IO::AIO::poll_cb);
		2222
1407	=head2 FORK BEHAVIOUR	2223	=head2 FORK BEHAVIOUR
1408		2224
1409	This module should do "the right thing" when the process using it forks:	2225	Usage of pthreads in a program changes the semantics of fork
		2226	considerably. Specifically, only async-safe functions can be called after
		2227	fork. Perl doesn't know about this, so in general, you cannot call fork
		2228	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2229	pthreads, so this applies, but many other extensions and (for inexplicable
		2230	reasons) perl itself often is linked against pthreads, so this limitation
		2231	applies to quite a lot of perls.
1410		2232
1411	Before the fork, IO::AIO enters a quiescent state where no requests	2233	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1412	can be added in other threads and no results will be processed. After	2234	only works in the process that loaded it. Forking is fully supported, but
1413	the fork the parent simply leaves the quiescent state and continues	2235	using IO::AIO in the child is not.
1414	request/result processing, while the child frees the request/result queue
1415	(so that the requests started before the fork will only be handled in the
1416	parent). Threads will be started on demand until the limit set in the
1417	parent process has been reached again.
1418		2236
1419	In short: the parent will, after a short pause, continue as if fork had	2237	You might get around by not I<using> IO::AIO before (or after)
1420	not been called, while the child will act as if IO::AIO has not been used	2238	forking. You could also try to call the L<IO::AIO::reinit> function in the
1421	yet.	2239	child:
		2240
		2241	=over 4
		2242
		2243	=item IO::AIO::reinit
		2244
		2245	Abandons all current requests and I/O threads and simply reinitialises all
		2246	data structures. This is not an operation supported by any standards, but
		2247	happens to work on GNU/Linux and some newer BSD systems.
		2248
		2249	The only reasonable use for this function is to call it after forking, if
		2250	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2251	the process will result in undefined behaviour. Calling it at any time
		2252	will also result in any undefined (by POSIX) behaviour.
		2253
		2254	=back
1422		2255
1423	=head2 MEMORY USAGE	2256	=head2 MEMORY USAGE
1424		2257
1425	Per-request usage:	2258	Per-request usage:
1426		2259

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