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Revision 1.116 by root, Wed Oct 3 21:27:51 2007 UTC vs.
Revision 1.194 by root, Fri May 27 00:44:49 2011 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
…		…
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	47	While most of this works on all types of file descriptors (for
68	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
69	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
70	inefficient. Use an event loop for that (such as the L<Event|Event>	50	very inefficient. Use an event loop for that (such as the L<EV>
71	module): IO::AIO will naturally fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
72		52
73	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
74	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
75	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
…		…
85	yourself, always call C<poll_cb> from within the same thread, or never	65	yourself, always call C<poll_cb> from within the same thread, or never
86	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
87		67
88	=head2 EXAMPLE	68	=head2 EXAMPLE
89		69
90	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
91	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
92		72
93	use Fcntl;	73	use Fcntl;
94	use Event;	74	use EV;
95	use IO::AIO;	75	use IO::AIO;
96		76
97	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
98	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
99	poll => 'r',
100	cb => \&IO::AIO::poll_cb);
101		79
102	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
103	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
104	my $fh = shift	82	my $fh = shift
105	or die "error while opening: $!";	83	or die "error while opening: $!";
106		84
107	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
108	my $size = -s $fh;	86	my $size = -s $fh;
…		…
117		95
118	# file contents now in $contents	96	# file contents now in $contents
119	print $contents;	97	print $contents;
120		98
121	# exit event loop and program	99	# exit event loop and program
122	Event::unloop;	100	EV::unloop;
123	};	101	};
124	};	102	};
125		103
126	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
127	# check for sockets etc. etc.	105	# check for sockets etc. etc.
128		106
129	# process events as long as there are some:	107	# process events as long as there are some:
130	Event::loop;	108	EV::loop;
131		109
132	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
133		111
134	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
135	directly visible to Perl.	113	directly visible to Perl.
…		…
183		161
184	=cut	162	=cut
185		163
186	package IO::AIO;	164	package IO::AIO;
187		165
188	no warnings;	166	use Carp ();
189	use strict 'vars';	167
		168	use common::sense;
190		169
191	use base 'Exporter';	170	use base 'Exporter';
192		171
193	BEGIN {	172	BEGIN {
194	our $VERSION = '2.5';	173	our $VERSION = '3.9';
195		174
196	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
197	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
198	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
199	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
200	aio_chown 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
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 idle_timeout
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::idle_timeout $seconds
		264	IO::AIO::max_outstanding $maxreqs
		265	IO::AIO::nreqs
		266	IO::AIO::nready
		267	IO::AIO::npending
		268
		269	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		270	IO::AIO::fadvise $fh, $offset, $len, $advice
		271	IO::AIO::madvise $scalar, $offset, $length, $advice
		272	IO::AIO::mprotect $scalar, $offset, $length, $protect
		273	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		274	IO::AIO::munlockall
214		275
215	=head2 AIO REQUEST FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
216		277
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	280	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	281	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	282	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	283	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	284	syscall has been executed asynchronously.
224		285
225	All functions expecting a filehandle keep a copy of the filehandle	286	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	287	internally until the request has finished.
227		288
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	302	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)	303	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	304	use something else to ensure your scalar has the correct contents.
244		305
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	307	handles correctly whether it is set or not.
247		308
248	=over 4	309	=over 4
249		310
250	=item $prev_pri = aioreq_pri [$pri]	311	=item $prev_pri = aioreq_pri [$pri]
251		312
…		…
298	by the umask in effect then the request is being executed, so better never	359	by the umask in effect then the request is being executed, so better never
299	change the umask.	360	change the umask.
300		361
301	Example:	362	Example:
302		363
303	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
304	if ($_[0]) {	365	if ($_[0]) {
305	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
306	...	367	...
307	} else {	368	} else {
308	die "open failed: $!\n";	369	die "open failed: $!\n";
309	}	370	}
310	};	371	};
311		372
		373	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		374	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		375	following POSIX and non-POSIX constants are available (missing ones on
		376	your system are, as usual, C<0>):
		377
		378	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		379	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		380	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		381
312		382
313	=item aio_close $fh, $callback->($status)	383	=item aio_close $fh, $callback->($status)
314		384
315	Asynchronously close a file and call the callback with the result	385	Asynchronously close a file and call the callback with the result
316	code.	386	code.
317		387
318	Unlike the other functions operating on files, this function uses the	388	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
319	PerlIO layer to close the filehandle. The reason is that the PerlIO API	389	closing the file descriptor associated with the filehandle itself.
320	insists on closing the underlying fd itself, no matter what, and doesn't
321	allow modifications to the fd. Unfortunately, it is not clear that you can
322	call PerlIO from different threads (actually, its quite clear that this
323	won't work in some cases), so while it likely works perfectly with simple
324	file handles (such as the ones created by C<aio_open>) it might fail in
325	interesting ways for others.
326		390
327	Having said that, aio_close tries to clean up the filehandle as much as	391	Therefore, C<aio_close> will not close the filehandle - instead it will
328	possible before handing it to an io thread, and generally does work.	392	use dup2 to overwrite the file descriptor with the write-end of a pipe
		393	(the pipe fd will be created on demand and will be cached).
329		394
		395	Or in other words: the file descriptor will be closed, but it will not be
		396	free for reuse until the perl filehandle is closed.
		397
		398	=cut
330		399
331	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	400	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
332		401
333	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	402	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
334		403
335	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>	404	Reads or writes C<$length> bytes from or to the specified C<$fh> and
336	into the scalar given by C<$data> and offset C<$dataoffset> and calls the	405	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
337	callback without the actual number of bytes read (or -1 on error, just	406	and calls the callback without the actual number of bytes read (or -1 on
338	like the syscall).	407	error, just like the syscall).
		408
		409	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		410	offset plus the actual number of bytes read.
339		411
340	If C<$offset> is undefined, then the current file descriptor offset will	412	If C<$offset> is undefined, then the current file descriptor offset will
341	be used (and updated), otherwise the file descriptor offset will not be	413	be used (and updated), otherwise the file descriptor offset will not be
342	changed by these calls.	414	changed by these calls.
343		415
344	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.	416	If C<$length> is undefined in C<aio_write>, use the remaining length of
		417	C<$data>.
345		418
346	If C<$dataoffset> is less than zero, it will be counted from the end of	419	If C<$dataoffset> is less than zero, it will be counted from the end of
347	C<$data>.	420	C<$data>.
348		421
349	The C<$data> scalar I<MUST NOT> be modified in any way while the request	422	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
365	reading at byte offset C<$in_offset>, and starts writing at the current	438	reading at byte offset C<$in_offset>, and starts writing at the current
366	file offset of C<$out_fh>. Because of that, it is not safe to issue more	439	file offset of C<$out_fh>. Because of that, it is not safe to issue more
367	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	440	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
368	other.	441	other.
369		442
		443	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		444	are written, and there is no way to find out how many bytes have been read
		445	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
		446	bytes written to C<$out_fh>. Only if the result value equals C<$length>
		447	one can assume that C<$length> bytes have been read.
		448
		449	Unlike with other C<aio_> functions, it makes a lot of sense to use
		450	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		451	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		452	the socket I/O will be non-blocking. Note, however, that you can run into
		453	a trap where C<aio_sendfile> reads some data with readahead, then fails
		454	to write all data, and when the socket is ready the next time, the data
		455	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		456	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		457	much better.
		458
370	This call tries to make use of a native C<sendfile> syscall to provide	459	This call tries to make use of a native C<sendfile> syscall to provide
371	zero-copy operation. For this to work, C<$out_fh> should refer to a	460	zero-copy operation. For this to work, C<$out_fh> should refer to a
372	socket, and C<$in_fh> should refer to mmap'able file.	461	socket, and C<$in_fh> should refer to an mmap'able file.
373		462
374	If the native sendfile call fails or is not implemented, it will be	463	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		464	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
375	emulated, so you can call C<aio_sendfile> on any type of filehandle	465	it will be emulated, so you can call C<aio_sendfile> on any type of
376	regardless of the limitations of the operating system.	466	filehandle regardless of the limitations of the operating system.
377
378	Please note, however, that C<aio_sendfile> can read more bytes from
379	C<$in_fh> than are written, and there is no way to find out how many
380	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
381	provides the number of bytes written to C<$out_fh>. Only if the result
382	value equals C<$length> one can assume that C<$length> bytes have been
383	read.
384		467
385		468
386	=item aio_readahead $fh,$offset,$length, $callback->($retval)	469	=item aio_readahead $fh,$offset,$length, $callback->($retval)
387		470
388	C<aio_readahead> populates the page cache with data from a file so that	471	C<aio_readahead> populates the page cache with data from a file so that
…		…
411		494
412	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	495	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
413	error when stat'ing a large file, the results will be silently truncated	496	error when stat'ing a large file, the results will be silently truncated
414	unless perl itself is compiled with large file support.	497	unless perl itself is compiled with large file support.
415		498
		499	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		500	following constants and functions (if not implemented, the constants will
		501	be C<0> and the functions will either C<croak> or fall back on traditional
		502	behaviour).
		503
		504	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		505	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		506	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		507
416	Example: Print the length of F</etc/passwd>:	508	Example: Print the length of F</etc/passwd>:
417		509
418	aio_stat "/etc/passwd", sub {	510	aio_stat "/etc/passwd", sub {
419	$_[0] and die "stat failed: $!";	511	$_[0] and die "stat failed: $!";
420	print "size is ", -s _, "\n";	512	print "size is ", -s _, "\n";
421	};	513	};
422		514
423		515
		516	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		517
		518	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		519	whether a file handle or path was passed.
		520
		521	On success, the callback is passed a hash reference with the following
		522	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		523	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		524	is passed.
		525
		526	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		527	C<ST_NOSUID>.
		528
		529	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		530	their correct value when available, or to C<0> on systems that do
		531	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		532	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		533	C<ST_NODIRATIME> and C<ST_RELATIME>.
		534
		535	Example: stat C</wd> and dump out the data if successful.
		536
		537	aio_statvfs "/wd", sub {
		538	my $f = $_[0]
		539	or die "statvfs: $!";
		540
		541	use Data::Dumper;
		542	say Dumper $f;
		543	};
		544
		545	# result:
		546	{
		547	bsize => 1024,
		548	bfree => 4333064312,
		549	blocks => 10253828096,
		550	files => 2050765568,
		551	flag => 4096,
		552	favail => 2042092649,
		553	bavail => 4333064312,
		554	ffree => 2042092649,
		555	namemax => 255,
		556	frsize => 1024,
		557	fsid => 1810
		558	}
		559
		560
424	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
425		562
426	Works like perl's C<utime> function (including the special case of $atime	563	Works like perl's C<utime> function (including the special case of $atime
427	and $mtime being undef). Fractional times are supported if the underlying	564	and $mtime being undef). Fractional times are supported if the underlying
428	syscalls support them.	565	syscalls support them.
…		…
476		613
477	The only (POSIX-) portable way of calling this function is:	614	The only (POSIX-) portable way of calling this function is:
478		615
479	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	616	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
480		617
		618	See C<aio_stat> for info about some potentially helpful extra constants
		619	and functions.
481		620
482	=item aio_link $srcpath, $dstpath, $callback->($status)	621	=item aio_link $srcpath, $dstpath, $callback->($status)
483		622
484	Asynchronously create a new link to the existing object at C<$srcpath> at	623	Asynchronously create a new link to the existing object at C<$srcpath> at
485	the path C<$dstpath> and call the callback with the result code.	624	the path C<$dstpath> and call the callback with the result code.
…		…
521		660
522	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	661	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
523	directory (i.e. opendir + readdir + closedir). The entries will not be	662	directory (i.e. opendir + readdir + closedir). The entries will not be
524	sorted, and will B<NOT> include the C<.> and C<..> entries.	663	sorted, and will B<NOT> include the C<.> and C<..> entries.
525		664
526	The callback a single argument which is either C<undef> or an array-ref	665	The callback is passed a single argument which is either C<undef> or an
527	with the filenames.	666	array-ref with the filenames.
		667
		668
		669	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		670
		671	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		672	behaviour and output format. In case of an error, C<$entries> will be
		673	C<undef>.
		674
		675	The flags are a combination of the following constants, ORed together (the
		676	flags will also be passed to the callback, possibly modified):
		677
		678	=over 4
		679
		680	=item IO::AIO::READDIR_DENTS
		681
		682	When this flag is off, then the callback gets an arrayref consisting of
		683	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		684	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		685	entry in more detail.
		686
		687	C<$name> is the name of the entry.
		688
		689	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		690
		691	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		692	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		693	C<IO::AIO::DT_WHT>.
		694
		695	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		696	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		697	scalars are read-only: you can not modify them.
		698
		699	C<$inode> is the inode number (which might not be exact on systems with 64
		700	bit inode numbers and 32 bit perls). This field has unspecified content on
		701	systems that do not deliver the inode information.
		702
		703	=item IO::AIO::READDIR_DIRS_FIRST
		704
		705	When this flag is set, then the names will be returned in an order where
		706	likely directories come first, in optimal stat order. This is useful when
		707	you need to quickly find directories, or you want to find all directories
		708	while avoiding to stat() each entry.
		709
		710	If the system returns type information in readdir, then this is used
		711	to find directories directly. Otherwise, likely directories are names
		712	beginning with ".", or otherwise names with no dots, of which names with
		713	short names are tried first.
		714
		715	=item IO::AIO::READDIR_STAT_ORDER
		716
		717	When this flag is set, then the names will be returned in an order
		718	suitable for stat()'ing each one. That is, when you plan to stat()
		719	all files in the given directory, then the returned order will likely
		720	be fastest.
		721
		722	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		723	the likely dirs come first, resulting in a less optimal stat order.
		724
		725	=item IO::AIO::READDIR_FOUND_UNKNOWN
		726
		727	This flag should not be set when calling C<aio_readdirx>. Instead, it
		728	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		729	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		730	C<$type>'s are known, which can be used to speed up some algorithms.
		731
		732	=back
528		733
529		734
530	=item aio_load $path, $data, $callback->($status)	735	=item aio_load $path, $data, $callback->($status)
531		736
532	This is a composite request that tries to fully load the given file into	737	This is a composite request that tries to fully load the given file into
533	memory. Status is the same as with aio_read.	738	memory. Status is the same as with aio_read.
534		739
535	=cut	740	=cut
536		741
537	sub aio_load($$;$) {	742	sub aio_load($$;$) {
538	aio_block {
539	my ($path, undef, $cb) = @_;	743	my ($path, undef, $cb) = @_;
540	my $data = \$_[1];	744	my $data = \$_[1];
541		745
542	my $pri = aioreq_pri;	746	my $pri = aioreq_pri;
543	my $grp = aio_group $cb;	747	my $grp = aio_group $cb;
		748
		749	aioreq_pri $pri;
		750	add $grp aio_open $path, O_RDONLY, 0, sub {
		751	my $fh = shift
		752	or return $grp->result (-1);
544		753
545	aioreq_pri $pri;	754	aioreq_pri $pri;
546	add $grp aio_open $path, O_RDONLY, 0, sub {
547	my $fh = shift
548	or return $grp->result (-1);
549
550	aioreq_pri $pri;
551	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	755	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
552	$grp->result ($_[0]);	756	$grp->result ($_[0]);
553	};
554	};	757	};
555
556	$grp
557	}	758	};
		759
		760	$grp
558	}	761	}
559		762
560	=item aio_copy $srcpath, $dstpath, $callback->($status)	763	=item aio_copy $srcpath, $dstpath, $callback->($status)
561		764
562	Try to copy the I<file> (directories not supported as either source or	765	Try to copy the I<file> (directories not supported as either source or
563	destination) from C<$srcpath> to C<$dstpath> and call the callback with	766	destination) from C<$srcpath> to C<$dstpath> and call the callback with
564	the C<0> (error) or C<-1> ok.	767	a status of C<0> (ok) or C<-1> (error, see C<$!>).
565		768
566	This is a composite request that it creates the destination file with	769	This is a composite request that creates the destination file with
567	mode 0200 and copies the contents of the source file into it using	770	mode 0200 and copies the contents of the source file into it using
568	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	771	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
569	uid/gid, in that order.	772	uid/gid, in that order.
570		773
571	If an error occurs, the partial destination file will be unlinked, if	774	If an error occurs, the partial destination file will be unlinked, if
…		…
573	errors are being ignored.	776	errors are being ignored.
574		777
575	=cut	778	=cut
576		779
577	sub aio_copy($$;$) {	780	sub aio_copy($$;$) {
578	aio_block {
579	my ($src, $dst, $cb) = @_;	781	my ($src, $dst, $cb) = @_;
580		782
581	my $pri = aioreq_pri;	783	my $pri = aioreq_pri;
582	my $grp = aio_group $cb;	784	my $grp = aio_group $cb;
583		785
584	aioreq_pri $pri;	786	aioreq_pri $pri;
585	add $grp aio_open $src, O_RDONLY, 0, sub {	787	add $grp aio_open $src, O_RDONLY, 0, sub {
586	if (my $src_fh = $_[0]) {	788	if (my $src_fh = $_[0]) {
587	my @stat = stat $src_fh;	789	my @stat = stat $src_fh; # hmm, might block over nfs?
588		790
589	aioreq_pri $pri;	791	aioreq_pri $pri;
590	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	792	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
591	if (my $dst_fh = $_[0]) {	793	if (my $dst_fh = $_[0]) {
592	aioreq_pri $pri;	794	aioreq_pri $pri;
593	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	795	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
594	if ($_[0] == $stat[7]) {	796	if ($_[0] == $stat[7]) {
595	$grp->result (0);	797	$grp->result (0);
596	close $src_fh;	798	close $src_fh;
597		799
598	# those should not normally block. should. should.
599	utime $stat[8], $stat[9], $dst;
600	chmod $stat[2] & 07777, $dst_fh;
601	chown $stat[4], $stat[5], $dst_fh;
602	close $dst_fh;
603	} else {	800	my $ch = sub {
604	$grp->result (-1);
605	close $src_fh;
606	close $dst_fh;
607
608	aioreq $pri;	801	aioreq_pri $pri;
		802	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		803	aioreq_pri $pri;
		804	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		805	aioreq_pri $pri;
609	add $grp aio_unlink $dst;	806	add $grp aio_close $dst_fh;
		807	}
		808	};
610	}	809	};
		810
		811	aioreq_pri $pri;
		812	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		813	if ($_[0] < 0 && $! == ENOSYS) {
		814	aioreq_pri $pri;
		815	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		816	} else {
		817	$ch->();
		818	}
		819	};
		820	} else {
		821	$grp->result (-1);
		822	close $src_fh;
		823	close $dst_fh;
		824
		825	aioreq $pri;
		826	add $grp aio_unlink $dst;
611	};	827	}
612	} else {
613	$grp->result (-1);
614	}	828	};
		829	} else {
		830	$grp->result (-1);
615	},	831	}
616
617	} else {
618	$grp->result (-1);
619	}	832	},
		833
		834	} else {
		835	$grp->result (-1);
620	};	836	}
621
622	$grp
623	}	837	};
		838
		839	$grp
624	}	840	}
625		841
626	=item aio_move $srcpath, $dstpath, $callback->($status)	842	=item aio_move $srcpath, $dstpath, $callback->($status)
627		843
628	Try to move the I<file> (directories not supported as either source or	844	Try to move the I<file> (directories not supported as either source or
629	destination) from C<$srcpath> to C<$dstpath> and call the callback with	845	destination) from C<$srcpath> to C<$dstpath> and call the callback with
630	the C<0> (error) or C<-1> ok.	846	a status of C<0> (ok) or C<-1> (error, see C<$!>).
631		847
632	This is a composite request that tries to rename(2) the file first. If	848	This is a composite request that tries to rename(2) the file first; if
633	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	849	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
634	that is successful, unlinking the C<$srcpath>.	850	that is successful, unlinks the C<$srcpath>.
635		851
636	=cut	852	=cut
637		853
638	sub aio_move($$;$) {	854	sub aio_move($$;$) {
639	aio_block {
640	my ($src, $dst, $cb) = @_;	855	my ($src, $dst, $cb) = @_;
641		856
642	my $pri = aioreq_pri;	857	my $pri = aioreq_pri;
643	my $grp = aio_group $cb;	858	my $grp = aio_group $cb;
644		859
645	aioreq_pri $pri;	860	aioreq_pri $pri;
646	add $grp aio_rename $src, $dst, sub {	861	add $grp aio_rename $src, $dst, sub {
647	if ($_[0] && $! == EXDEV) {	862	if ($_[0] && $! == EXDEV) {
648	aioreq_pri $pri;	863	aioreq_pri $pri;
649	add $grp aio_copy $src, $dst, sub {	864	add $grp aio_copy $src, $dst, sub {
650	$grp->result ($_[0]);
651
652	if (!$_[0]) {
653	aioreq_pri $pri;
654	add $grp aio_unlink $src;
655	}
656	};
657	} else {
658	$grp->result ($_[0]);	865	$grp->result ($_[0]);
		866
		867	if (!$_[0]) {
		868	aioreq_pri $pri;
		869	add $grp aio_unlink $src;
		870	}
659	}	871	};
		872	} else {
		873	$grp->result ($_[0]);
660	};	874	}
661
662	$grp
663	}	875	};
		876
		877	$grp
664	}	878	}
665		879
666	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	880	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
667		881
668	Scans a directory (similar to C<aio_readdir>) but additionally tries to	882	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
688		902
689	Implementation notes.	903	Implementation notes.
690		904
691	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	905	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
692		906
		907	If readdir returns file type information, then this is used directly to
		908	find directories.
		909
693	After reading the directory, the modification time, size etc. of the	910	Otherwise, after reading the directory, the modification time, size etc.
694	directory before and after the readdir is checked, and if they match (and	911	of the directory before and after the readdir is checked, and if they
695	isn't the current time), the link count will be used to decide how many	912	match (and isn't the current time), the link count will be used to decide
696	entries are directories (if >= 2). Otherwise, no knowledge of the number	913	how many entries are directories (if >= 2). Otherwise, no knowledge of the
697	of subdirectories will be assumed.	914	number of subdirectories will be assumed.
698		915
699	Then entries will be sorted into likely directories (everything without	916	Then entries will be sorted into likely directories a non-initial dot
700	a non-initial dot currently) and likely non-directories (everything	917	currently) and likely non-directories (see C<aio_readdirx>). Then every
701	else). Then every entry plus an appended C</.> will be C<stat>'ed,	918	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
702	likely directories first. If that succeeds, it assumes that the entry	919	in order of their inode numbers. If that succeeds, it assumes that the
703	is a directory or a symlink to directory (which will be checked	920	entry is a directory or a symlink to directory (which will be checked
704	seperately). This is often faster than stat'ing the entry itself because	921	seperately). This is often faster than stat'ing the entry itself because
705	filesystems might detect the type of the entry without reading the inode	922	filesystems might detect the type of the entry without reading the inode
706	data (e.g. ext2fs filetype feature).	923	data (e.g. ext2fs filetype feature), even on systems that cannot return
		924	the filetype information on readdir.
707		925
708	If the known number of directories (link count - 2) has been reached, the	926	If the known number of directories (link count - 2) has been reached, the
709	rest of the entries is assumed to be non-directories.	927	rest of the entries is assumed to be non-directories.
710		928
711	This only works with certainty on POSIX (= UNIX) filesystems, which	929	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
716	directory counting heuristic.	934	directory counting heuristic.
717		935
718	=cut	936	=cut
719		937
720	sub aio_scandir($$;$) {	938	sub aio_scandir($$;$) {
721	aio_block {
722	my ($path, $maxreq, $cb) = @_;	939	my ($path, $maxreq, $cb) = @_;
723		940
724	my $pri = aioreq_pri;	941	my $pri = aioreq_pri;
725		942
726	my $grp = aio_group $cb;	943	my $grp = aio_group $cb;
727		944
728	$maxreq = 4 if $maxreq <= 0;	945	$maxreq = 4 if $maxreq <= 0;
729		946
730	# stat once	947	# stat once
		948	aioreq_pri $pri;
		949	add $grp aio_stat $path, sub {
		950	return $grp->result () if $_[0];
		951	my $now = time;
		952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		953
		954	# read the directory entries
731	aioreq_pri $pri;	955	aioreq_pri $pri;
732	add $grp aio_stat $path, sub {	956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		957	my $entries = shift
733	return $grp->result () if $_[0];	958	or return $grp->result ();
734	my $now = time;
735	my $hash1 = join ":", (stat _)[0,1,3,7,9];
736		959
737	# read the directory entries	960	# stat the dir another time
738	aioreq_pri $pri;	961	aioreq_pri $pri;
739	add $grp aio_readdir $path, sub {
740	my $entries = shift
741	or return $grp->result ();
742
743	# stat the dir another time
744	aioreq_pri $pri;
745	add $grp aio_stat $path, sub {	962	add $grp aio_stat $path, sub {
746	my $hash2 = join ":", (stat _)[0,1,3,7,9];	963	my $hash2 = join ":", (stat _)[0,1,3,7,9];
747		964
748	my $ndirs;	965	my $ndirs;
749		966
750	# take the slow route if anything looks fishy	967	# take the slow route if anything looks fishy
751	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
752	$ndirs = -1;	969	$ndirs = -1;
753	} else {	970	} else {
754	# if nlink == 2, we are finished	971	# if nlink == 2, we are finished
755	# on non-posix-fs's, we rely on nlink < 2	972	# for non-posix-fs's, we rely on nlink < 2
756	$ndirs = (stat _)[3] - 2	973	$ndirs = (stat _)[3] - 2
757	or return $grp->result ([], $entries);	974	or return $grp->result ([], $entries);
758	}	975	}
759		976
760	# sort into likely dirs and likely nondirs
761	# dirs == files without ".", short entries first
762	$entries = [map $_->[0],
763	sort { $b->[1] cmp $a->[1] }
764	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
765	@$entries];
766
767	my (@dirs, @nondirs);	977	my (@dirs, @nondirs);
768		978
769	my $statgrp = add $grp aio_group sub {	979	my $statgrp = add $grp aio_group sub {
770	$grp->result (\@dirs, \@nondirs);	980	$grp->result (\@dirs, \@nondirs);
771	};	981	};
772		982
773	limit $statgrp $maxreq;	983	limit $statgrp $maxreq;
774	feed $statgrp sub {	984	feed $statgrp sub {
775	return unless @$entries;	985	return unless @$entries;
776	my $entry = pop @$entries;	986	my $entry = shift @$entries;
777		987
778	aioreq_pri $pri;	988	aioreq_pri $pri;
779	add $statgrp aio_stat "$path/$entry/.", sub {	989	add $statgrp aio_stat "$path/$entry/.", sub {
780	if ($_[0] < 0) {	990	if ($_[0] < 0) {
781	push @nondirs, $entry;	991	push @nondirs, $entry;
782	} else {	992	} else {
783	# need to check for real directory	993	# need to check for real directory
784	aioreq_pri $pri;	994	aioreq_pri $pri;
785	add $statgrp aio_lstat "$path/$entry", sub {	995	add $statgrp aio_lstat "$path/$entry", sub {
786	if (-d _) {	996	if (-d _) {
787	push @dirs, $entry;	997	push @dirs, $entry;
788		998
789	unless (--$ndirs) {	999	unless (--$ndirs) {
790	push @nondirs, @$entries;	1000	push @nondirs, @$entries;
791	feed $statgrp;	1001	feed $statgrp;
792	}
793	} else {
794	push @nondirs, $entry;
795	}	1002	}
		1003	} else {
		1004	push @nondirs, $entry;
796	}	1005	}
797	}	1006	}
798	};	1007	}
799	};	1008	};
800	};	1009	};
801	};	1010	};
802	};	1011	};
803
804	$grp
805	}	1012	};
		1013
		1014	$grp
806	}	1015	}
807		1016
808	=item aio_rmtree $path, $callback->($status)	1017	=item aio_rmtree $path, $callback->($status)
809		1018
810	Delete a directory tree starting (and including) C<$path>, return the	1019	Delete a directory tree starting (and including) C<$path>, return the
…		…
814		1023
815	=cut	1024	=cut
816		1025
817	sub aio_rmtree;	1026	sub aio_rmtree;
818	sub aio_rmtree($;$) {	1027	sub aio_rmtree($;$) {
819	aio_block {
820	my ($path, $cb) = @_;	1028	my ($path, $cb) = @_;
821		1029
822	my $pri = aioreq_pri;	1030	my $pri = aioreq_pri;
823	my $grp = aio_group $cb;	1031	my $grp = aio_group $cb;
824		1032
825	aioreq_pri $pri;	1033	aioreq_pri $pri;
826	add $grp aio_scandir $path, 0, sub {	1034	add $grp aio_scandir $path, 0, sub {
827	my ($dirs, $nondirs) = @_;	1035	my ($dirs, $nondirs) = @_;
828		1036
829	my $dirgrp = aio_group sub {	1037	my $dirgrp = aio_group sub {
830	add $grp aio_rmdir $path, sub {	1038	add $grp aio_rmdir $path, sub {
831	$grp->result ($_[0]);	1039	$grp->result ($_[0]);
832	};
833	};	1040	};
834
835	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
836	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
837
838	add $grp $dirgrp;
839	};	1041	};
840		1042
841	$grp	1043	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1044	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1045
		1046	add $grp $dirgrp;
842	}	1047	};
		1048
		1049	$grp
843	}	1050	}
		1051
		1052	=item aio_sync $callback->($status)
		1053
		1054	Asynchronously call sync and call the callback when finished.
844		1055
845	=item aio_fsync $fh, $callback->($status)	1056	=item aio_fsync $fh, $callback->($status)
846		1057
847	Asynchronously call fsync on the given filehandle and call the callback	1058	Asynchronously call fsync on the given filehandle and call the callback
848	with the fsync result code.	1059	with the fsync result code.
…		…
852	Asynchronously call fdatasync on the given filehandle and call the	1063	Asynchronously call fdatasync on the given filehandle and call the
853	callback with the fdatasync result code.	1064	callback with the fdatasync result code.
854		1065
855	If this call isn't available because your OS lacks it or it couldn't be	1066	If this call isn't available because your OS lacks it or it couldn't be
856	detected, it will be emulated by calling C<fsync> instead.	1067	detected, it will be emulated by calling C<fsync> instead.
		1068
		1069	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1070
		1071	Sync the data portion of the file specified by C<$offset> and C<$length>
		1072	to disk (but NOT the metadata), by calling the Linux-specific
		1073	sync_file_range call. If sync_file_range is not available or it returns
		1074	ENOSYS, then fdatasync or fsync is being substituted.
		1075
		1076	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1077	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1078	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1079	manpage for details.
		1080
		1081	=item aio_pathsync $path, $callback->($status)
		1082
		1083	This request tries to open, fsync and close the given path. This is a
		1084	composite request intended to sync directories after directory operations
		1085	(E.g. rename). This might not work on all operating systems or have any
		1086	specific effect, but usually it makes sure that directory changes get
		1087	written to disc. It works for anything that can be opened for read-only,
		1088	not just directories.
		1089
		1090	Future versions of this function might fall back to other methods when
		1091	C<fsync> on the directory fails (such as calling C<sync>).
		1092
		1093	Passes C<0> when everything went ok, and C<-1> on error.
		1094
		1095	=cut
		1096
		1097	sub aio_pathsync($;$) {
		1098	my ($path, $cb) = @_;
		1099
		1100	my $pri = aioreq_pri;
		1101	my $grp = aio_group $cb;
		1102
		1103	aioreq_pri $pri;
		1104	add $grp aio_open $path, O_RDONLY, 0, sub {
		1105	my ($fh) = @_;
		1106	if ($fh) {
		1107	aioreq_pri $pri;
		1108	add $grp aio_fsync $fh, sub {
		1109	$grp->result ($_[0]);
		1110
		1111	aioreq_pri $pri;
		1112	add $grp aio_close $fh;
		1113	};
		1114	} else {
		1115	$grp->result (-1);
		1116	}
		1117	};
		1118
		1119	$grp
		1120	}
		1121
		1122	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1123
		1124	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1125	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1126	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1127	scalar must only be modified in-place while an aio operation is pending on
		1128	it).
		1129
		1130	It calls the C<msync> function of your OS, if available, with the memory
		1131	area starting at C<$offset> in the string and ending C<$length> bytes
		1132	later. If C<$length> is negative, counts from the end, and if C<$length>
		1133	is C<undef>, then it goes till the end of the string. The flags can be
		1134	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1135	C<IO::AIO::MS_SYNC>.
		1136
		1137	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1138
		1139	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1140	scalars.
		1141
		1142	It touches (reads or writes) all memory pages in the specified
		1143	range inside the scalar. All caveats and parameters are the same
		1144	as for C<aio_msync>, above, except for flags, which must be either
		1145	C<0> (which reads all pages and ensures they are instantiated) or
		1146	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1147	writing an octet from it, which dirties the page).
		1148
		1149	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1150
		1151	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1152	scalars.
		1153
		1154	It reads in all the pages of the underlying storage into memory (if any)
		1155	and locks them, so they are not getting swapped/paged out or removed.
		1156
		1157	If C<$length> is undefined, then the scalar will be locked till the end.
		1158
		1159	On systems that do not implement C<mlock>, this function returns C<-1>
		1160	and sets errno to C<ENOSYS>.
		1161
		1162	Note that the corresponding C<munlock> is synchronous and is
		1163	documented under L<MISCELLANEOUS FUNCTIONS>.
		1164
		1165	Example: open a file, mmap and mlock it - both will be undone when
		1166	C<$data> gets destroyed.
		1167
		1168	open my $fh, "<", $path or die "$path: $!";
		1169	my $data;
		1170	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1171	aio_mlock $data; # mlock in background
		1172
		1173	=item aio_mlockall $flags, $callback->($status)
		1174
		1175	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1176	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1177
		1178	On systems that do not implement C<mlockall>, this function returns C<-1>
		1179	and sets errno to C<ENOSYS>.
		1180
		1181	Note that the corresponding C<munlockall> is synchronous and is
		1182	documented under L<MISCELLANEOUS FUNCTIONS>.
		1183
		1184	Example: asynchronously lock all current and future pages into memory.
		1185
		1186	aio_mlockall IO::AIO::MCL_FUTURE;
857		1187
858	=item aio_group $callback->(...)	1188	=item aio_group $callback->(...)
859		1189
860	This is a very special aio request: Instead of doing something, it is a	1190	This is a very special aio request: Instead of doing something, it is a
861	container for other aio requests, which is useful if you want to bundle	1191	container for other aio requests, which is useful if you want to bundle
…		…
911	=item cancel $req	1241	=item cancel $req
912		1242
913	Cancels the request, if possible. Has the effect of skipping execution	1243	Cancels the request, if possible. Has the effect of skipping execution
914	when entering the B<execute> state and skipping calling the callback when	1244	when entering the B<execute> state and skipping calling the callback when
915	entering the the B<result> state, but will leave the request otherwise	1245	entering the the B<result> state, but will leave the request otherwise
916	untouched. That means that requests that currently execute will not be	1246	untouched (with the exception of readdir). That means that requests that
917	stopped and resources held by the request will not be freed prematurely.	1247	currently execute will not be stopped and resources held by the request
		1248	will not be freed prematurely.
918		1249
919	=item cb $req $callback->(...)	1250	=item cb $req $callback->(...)
920		1251
921	Replace (or simply set) the callback registered to the request.	1252	Replace (or simply set) the callback registered to the request.
922		1253
…		…
973	Their lifetime, simplified, looks like this: when they are empty, they	1304	Their lifetime, simplified, looks like this: when they are empty, they
974	will finish very quickly. If they contain only requests that are in the	1305	will finish very quickly. If they contain only requests that are in the
975	C<done> state, they will also finish. Otherwise they will continue to	1306	C<done> state, they will also finish. Otherwise they will continue to
976	exist.	1307	exist.
977		1308
978	That means after creating a group you have some time to add requests. And	1309	That means after creating a group you have some time to add requests
979	in the callbacks of those requests, you can add further requests to the	1310	(precisely before the callback has been invoked, which is only done within
980	group. And only when all those requests have finished will the the group	1311	the C<poll_cb>). And in the callbacks of those requests, you can add
981	itself finish.	1312	further requests to the group. And only when all those requests have
		1313	finished will the the group itself finish.
982		1314
983	=over 4	1315	=over 4
984		1316
985	=item add $grp ...	1317	=item add $grp ...
986		1318
…		…
995	=item $grp->cancel_subs	1327	=item $grp->cancel_subs
996		1328
997	Cancel all subrequests and clears any feeder, but not the group request	1329	Cancel all subrequests and clears any feeder, but not the group request
998	itself. Useful when you queued a lot of events but got a result early.	1330	itself. Useful when you queued a lot of events but got a result early.
999		1331
		1332	The group request will finish normally (you cannot add requests to the
		1333	group).
		1334
1000	=item $grp->result (...)	1335	=item $grp->result (...)
1001		1336
1002	Set the result value(s) that will be passed to the group callback when all	1337	Set the result value(s) that will be passed to the group callback when all
1003	subrequests have finished and set thre groups errno to the current value	1338	subrequests have finished and set the groups errno to the current value
1004	of errno (just like calling C<errno> without an error number). By default,	1339	of errno (just like calling C<errno> without an error number). By default,
1005	no argument will be passed and errno is zero.	1340	no argument will be passed and errno is zero.
1006		1341
1007	=item $grp->errno ([$errno])	1342	=item $grp->errno ([$errno])
1008		1343
…		…
1019	=item feed $grp $callback->($grp)	1354	=item feed $grp $callback->($grp)
1020		1355
1021	Sets a feeder/generator on this group: every group can have an attached	1356	Sets a feeder/generator on this group: every group can have an attached
1022	generator that generates requests if idle. The idea behind this is that,	1357	generator that generates requests if idle. The idea behind this is that,
1023	although you could just queue as many requests as you want in a group,	1358	although you could just queue as many requests as you want in a group,
1024	this might starve other requests for a potentially long time. For	1359	this might starve other requests for a potentially long time. For example,
1025	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1360	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1026	requests, delaying any later requests for a long time.	1361	delaying any later requests for a long time.
1027		1362
1028	To avoid this, and allow incremental generation of requests, you can	1363	To avoid this, and allow incremental generation of requests, you can
1029	instead a group and set a feeder on it that generates those requests. The	1364	instead a group and set a feeder on it that generates those requests. The
1030	feed callback will be called whenever there are few enough (see C<limit>,	1365	feed callback will be called whenever there are few enough (see C<limit>,
1031	below) requests active in the group itself and is expected to queue more	1366	below) requests active in the group itself and is expected to queue more
…		…
1035	not impose any limits).	1370	not impose any limits).
1036		1371
1037	If the feed does not queue more requests when called, it will be	1372	If the feed does not queue more requests when called, it will be
1038	automatically removed from the group.	1373	automatically removed from the group.
1039		1374
1040	If the feed limit is C<0>, it will be set to C<2> automatically.	1375	If the feed limit is C<0> when this method is called, it will be set to
		1376	C<2> automatically.
1041		1377
1042	Example:	1378	Example:
1043		1379
1044	# stat all files in @files, but only ever use four aio requests concurrently:	1380	# stat all files in @files, but only ever use four aio requests concurrently:
1045		1381
…		…
1057	Sets the feeder limit for the group: The feeder will be called whenever	1393	Sets the feeder limit for the group: The feeder will be called whenever
1058	the group contains less than this many requests.	1394	the group contains less than this many requests.
1059		1395
1060	Setting the limit to C<0> will pause the feeding process.	1396	Setting the limit to C<0> will pause the feeding process.
1061		1397
		1398	The default value for the limit is C<0>, but note that setting a feeder
		1399	automatically bumps it up to C<2>.
		1400
1062	=back	1401	=back
1063		1402
1064	=head2 SUPPORT FUNCTIONS	1403	=head2 SUPPORT FUNCTIONS
1065		1404
1066	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1405	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1068	=over 4	1407	=over 4
1069		1408
1070	=item $fileno = IO::AIO::poll_fileno	1409	=item $fileno = IO::AIO::poll_fileno
1071		1410
1072	Return the I<request result pipe file descriptor>. This filehandle must be	1411	Return the I<request result pipe file descriptor>. This filehandle must be
1073	polled for reading by some mechanism outside this module (e.g. Event or	1412	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1074	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1413	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1075	to call C<poll_cb> to check the results.	1414	you have to call C<poll_cb> to check the results.
1076		1415
1077	See C<poll_cb> for an example.	1416	See C<poll_cb> for an example.
1078		1417
1079	=item IO::AIO::poll_cb	1418	=item IO::AIO::poll_cb
1080		1419
1081	Process some outstanding events on the result pipe. You have to call this	1420	Process some outstanding events on the result pipe. You have to call
1082	regularly. Returns the number of events processed. Returns immediately	1421	this regularly. Returns C<0> if all events could be processed (or there
1083	when no events are outstanding. The amount of events processed depends on	1422	were no events to process), or C<-1> if it returned earlier for whatever
1084	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1423	reason. Returns immediately when no events are outstanding. The amount of
		1424	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1425	C<IO::AIO::max_poll_time>.
1085		1426
1086	If not all requests were processed for whatever reason, the filehandle	1427	If not all requests were processed for whatever reason, the filehandle
1087	will still be ready when C<poll_cb> returns.	1428	will still be ready when C<poll_cb> returns, so normally you don't have to
		1429	do anything special to have it called later.
		1430
		1431	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1432	ready, it can be beneficial to call this function from loops which submit
		1433	a lot of requests, to make sure the results get processed when they become
		1434	available and not just when the loop is finished and the event loop takes
		1435	over again. This function returns very fast when there are no outstanding
		1436	requests.
1088		1437
1089	Example: Install an Event watcher that automatically calls	1438	Example: Install an Event watcher that automatically calls
1090	IO::AIO::poll_cb with high priority:	1439	IO::AIO::poll_cb with high priority (more examples can be found in the
		1440	SYNOPSIS section, at the top of this document):
1091		1441
1092	Event->io (fd => IO::AIO::poll_fileno,	1442	Event->io (fd => IO::AIO::poll_fileno,
1093	poll => 'r', async => 1,	1443	poll => 'r', async => 1,
1094	cb => \&IO::AIO::poll_cb);	1444	cb => \&IO::AIO::poll_cb);
		1445
		1446	=item IO::AIO::poll_wait
		1447
		1448	If there are any outstanding requests and none of them in the result
		1449	phase, wait till the result filehandle becomes ready for reading (simply
		1450	does a C<select> on the filehandle. This is useful if you want to
		1451	synchronously wait for some requests to finish).
		1452
		1453	See C<nreqs> for an example.
		1454
		1455	=item IO::AIO::poll
		1456
		1457	Waits until some requests have been handled.
		1458
		1459	Returns the number of requests processed, but is otherwise strictly
		1460	equivalent to:
		1461
		1462	IO::AIO::poll_wait, IO::AIO::poll_cb
		1463
		1464	=item IO::AIO::flush
		1465
		1466	Wait till all outstanding AIO requests have been handled.
		1467
		1468	Strictly equivalent to:
		1469
		1470	IO::AIO::poll_wait, IO::AIO::poll_cb
		1471	while IO::AIO::nreqs;
1095		1472
1096	=item IO::AIO::max_poll_reqs $nreqs	1473	=item IO::AIO::max_poll_reqs $nreqs
1097		1474
1098	=item IO::AIO::max_poll_time $seconds	1475	=item IO::AIO::max_poll_time $seconds
1099		1476
…		…
1124	# use a low priority so other tasks have priority	1501	# use a low priority so other tasks have priority
1125	Event->io (fd => IO::AIO::poll_fileno,	1502	Event->io (fd => IO::AIO::poll_fileno,
1126	poll => 'r', nice => 1,	1503	poll => 'r', nice => 1,
1127	cb => &IO::AIO::poll_cb);	1504	cb => &IO::AIO::poll_cb);
1128		1505
1129	=item IO::AIO::poll_wait
1130
1131	If there are any outstanding requests and none of them in the result
1132	phase, wait till the result filehandle becomes ready for reading (simply
1133	does a C<select> on the filehandle. This is useful if you want to
1134	synchronously wait for some requests to finish).
1135
1136	See C<nreqs> for an example.
1137
1138	=item IO::AIO::poll
1139
1140	Waits until some requests have been handled.
1141
1142	Returns the number of requests processed, but is otherwise strictly
1143	equivalent to:
1144
1145	IO::AIO::poll_wait, IO::AIO::poll_cb
1146
1147	=item IO::AIO::flush
1148
1149	Wait till all outstanding AIO requests have been handled.
1150
1151	Strictly equivalent to:
1152
1153	IO::AIO::poll_wait, IO::AIO::poll_cb
1154	while IO::AIO::nreqs;
1155
1156	=back	1506	=back
1157		1507
1158	=head3 CONTROLLING THE NUMBER OF THREADS	1508	=head3 CONTROLLING THE NUMBER OF THREADS
1159		1509
1160	=over	1510	=over
…		…
1193		1543
1194	Under normal circumstances you don't need to call this function.	1544	Under normal circumstances you don't need to call this function.
1195		1545
1196	=item IO::AIO::max_idle $nthreads	1546	=item IO::AIO::max_idle $nthreads
1197		1547
1198	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1548	Limit the number of threads (default: 4) that are allowed to idle
1199	threads that did not get a request to process within 10 seconds). That	1549	(i.e., threads that did not get a request to process within the idle
1200	means if a thread becomes idle while C<$nthreads> other threads are also	1550	timeout (default: 10 seconds). That means if a thread becomes idle while
1201	idle, it will free its resources and exit.	1551	C<$nthreads> other threads are also idle, it will free its resources and
		1552	exit.
1202		1553
1203	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1554	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1204	to allow for extremely high load situations, but want to free resources	1555	to allow for extremely high load situations, but want to free resources
1205	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1556	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1206		1557
1207	The default is probably ok in most situations, especially if thread	1558	The default is probably ok in most situations, especially if thread
1208	creation is fast. If thread creation is very slow on your system you might	1559	creation is fast. If thread creation is very slow on your system you might
1209	want to use larger values.	1560	want to use larger values.
1210		1561
		1562	=item IO::AIO::idle_timeout $seconds
		1563
		1564	Sets the minimum idle timeout (default 10) after which worker threads are
		1565	allowed to exit. SEe C<IO::AIO::max_idle>.
		1566
1211	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1567	=item IO::AIO::max_outstanding $maxreqs
1212		1568
1213	This is a very bad function to use in interactive programs because it	1569	This is a very bad function to use in interactive programs because it
1214	blocks, and a bad way to reduce concurrency because it is inexact: Better	1570	blocks, and a bad way to reduce concurrency because it is inexact: Better
1215	use an C<aio_group> together with a feed callback.	1571	use an C<aio_group> together with a feed callback.
1216		1572
…		…
1221		1577
1222	The default value is very large, so there is no practical limit on the	1578	The default value is very large, so there is no practical limit on the
1223	number of outstanding requests.	1579	number of outstanding requests.
1224		1580
1225	You can still queue as many requests as you want. Therefore,	1581	You can still queue as many requests as you want. Therefore,
1226	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1582	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1227	as a stop gap to shield against fatal memory overflow (with large values).	1583	as a stop gap to shield against fatal memory overflow (with large values).
1228		1584
1229	=back	1585	=back
1230		1586
1231	=head3 STATISTICAL INFORMATION	1587	=head3 STATISTICAL INFORMATION
…		…
1252	Returns the number of requests currently in the pending state (executed,	1608	Returns the number of requests currently in the pending state (executed,
1253	but not yet processed by poll_cb).	1609	but not yet processed by poll_cb).
1254		1610
1255	=back	1611	=back
1256		1612
		1613	=head3 MISCELLANEOUS FUNCTIONS
		1614
		1615	IO::AIO implements some functions that might be useful, but are not
		1616	asynchronous.
		1617
		1618	=over 4
		1619
		1620	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1621
		1622	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1623	but is blocking (this makes most sense if you know the input data is
		1624	likely cached already and the output filehandle is set to non-blocking
		1625	operations).
		1626
		1627	Returns the number of bytes copied, or C<-1> on error.
		1628
		1629	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1630
		1631	Simply calls the C<posix_fadvise> function (see its
		1632	manpage for details). The following advice constants are
		1633	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1634	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1635	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1636
		1637	On systems that do not implement C<posix_fadvise>, this function returns
		1638	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1639
		1640	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1641
		1642	Simply calls the C<posix_madvise> function (see its
		1643	manpage for details). The following advice constants are
		1644	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1645	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1646
		1647	On systems that do not implement C<posix_madvise>, this function returns
		1648	ENOSYS, otherwise the return value of C<posix_madvise>.
		1649
		1650	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1651
		1652	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1653	$scalar (see its manpage for details). The following protect
		1654	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1655	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1656
		1657	On systems that do not implement C<mprotect>, this function returns
		1658	ENOSYS, otherwise the return value of C<mprotect>.
		1659
		1660	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1661
		1662	Memory-maps a file (or anonymous memory range) and attaches it to the
		1663	given C<$scalar>, which will act like a string scalar.
		1664
		1665	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1666	change the string length, and most read-only operations such as copying it
		1667	or searching it with regexes and so on.
		1668
		1669	Anything else is unsafe and will, at best, result in memory leaks.
		1670
		1671	The memory map associated with the C<$scalar> is automatically removed
		1672	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1673	C<IO::AIO::munmap> functions are called.
		1674
		1675	This calls the C<mmap>(2) function internally. See your system's manual
		1676	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1677
		1678	The C<$length> must be larger than zero and smaller than the actual
		1679	filesize.
		1680
		1681	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1682	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1683
		1684	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1685	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1686	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1687	(which is set to C<MAP_ANON> if your system only provides this
		1688	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1689	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1690	C<IO::AIO::MAP_NONBLOCK>
		1691
		1692	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1693
		1694	C<$offset> is the offset from the start of the file - it generally must be
		1695	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1696
		1697	Example:
		1698
		1699	use Digest::MD5;
		1700	use IO::AIO;
		1701
		1702	open my $fh, "<verybigfile"
		1703	or die "$!";
		1704
		1705	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1706	or die "verybigfile: $!";
		1707
		1708	my $fast_md5 = md5 $data;
		1709
		1710	=item IO::AIO::munmap $scalar
		1711
		1712	Removes a previous mmap and undefines the C<$scalar>.
		1713
		1714	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1715
		1716	Calls the C<munlock> function, undoing the effects of a previous
		1717	C<aio_mlock> call (see its description for details).
		1718
		1719	=item IO::AIO::munlockall
		1720
		1721	Calls the C<munlockall> function.
		1722
		1723	On systems that do not implement C<munlockall>, this function returns
		1724	ENOSYS, otherwise the return value of C<munlockall>.
		1725
		1726	=back
		1727
1257	=cut	1728	=cut
1258		1729
1259	min_parallel 8;	1730	min_parallel 8;
1260		1731
1261	END { flush }	1732	END { flush }
1262		1733
1263	1;	1734	1;
		1735
		1736	=head1 EVENT LOOP INTEGRATION
		1737
		1738	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1739	automatically into many event loops:
		1740
		1741	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1742	use AnyEvent::AIO;
		1743
		1744	You can also integrate IO::AIO manually into many event loops, here are
		1745	some examples of how to do this:
		1746
		1747	# EV integration
		1748	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1749
		1750	# Event integration
		1751	Event->io (fd => IO::AIO::poll_fileno,
		1752	poll => 'r',
		1753	cb => \&IO::AIO::poll_cb);
		1754
		1755	# Glib/Gtk2 integration
		1756	add_watch Glib::IO IO::AIO::poll_fileno,
		1757	in => sub { IO::AIO::poll_cb; 1 };
		1758
		1759	# Tk integration
		1760	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1761	readable => \&IO::AIO::poll_cb);
		1762
		1763	# Danga::Socket integration
		1764	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1765	\&IO::AIO::poll_cb);
1264		1766
1265	=head2 FORK BEHAVIOUR	1767	=head2 FORK BEHAVIOUR
1266		1768
1267	This module should do "the right thing" when the process using it forks:	1769	This module should do "the right thing" when the process using it forks:
1268		1770
…		…
1301		1803
1302	Known bugs will be fixed in the next release.	1804	Known bugs will be fixed in the next release.
1303		1805
1304	=head1 SEE ALSO	1806	=head1 SEE ALSO
1305		1807
1306	L<Coro::AIO>.	1808	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1809	more natural syntax.
1307		1810
1308	=head1 AUTHOR	1811	=head1 AUTHOR
1309		1812
1310	Marc Lehmann <schmorp@schmorp.de>	1813	Marc Lehmann <schmorp@schmorp.de>
1311	http://home.schmorp.de/	1814	http://home.schmorp.de/

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