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Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC vs.
Revision 1.178 by root, Sun Jan 10 23:10:58 2010 UTC

…		…
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", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
30	# AnyEvent integration
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33
34	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',
37	cb => \&IO::AIO::poll_cb);
38
39	# Glib/Gtk2 integration
40	add_watch Glib::IO IO::AIO::poll_fileno,
41	in => sub { IO::AIO::poll_cb; 1 };
42
43	# Tk integration
44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
45	readable => \&IO::AIO::poll_cb);
46
47	# Danga::Socket integration
48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
49	\&IO::AIO::poll_cb);
50
51	=head1 DESCRIPTION	31	=head1 DESCRIPTION
52		32
53	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
54	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
		36
		37	Asynchronous means that operations that can normally block your program
		38	(e.g. reading from disk) will be done asynchronously: the operation
		39	will still block, but you can do something else in the meantime. This
		40	is extremely useful for programs that need to stay interactive even
		41	when doing heavy I/O (GUI programs, high performance network servers
		42	etc.), but can also be used to easily do operations in parallel that are
		43	normally done sequentially, e.g. stat'ing many files, which is much faster
		44	on a RAID volume or over NFS when you do a number of stat operations
		45	concurrently.
		46
		47	While most of this works on all types of file descriptors (for
		48	example sockets), using these functions on file descriptors that
		49	support nonblocking operation (again, sockets, pipes etc.) is
		50	very inefficient. Use an event loop for that (such as the L<EV>
		51	module): IO::AIO will naturally fit into such an event loop itself.
55		52
56	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
57	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
58	in perl, and the threads created by this module will not be visible	55	in perl, and the threads created by this module will not be visible
59	to perl. In the future, this module might make use of the native aio	56	to perl. In the future, this module might make use of the native aio
60	functions available on many operating systems. However, they are often	57	functions available on many operating systems. However, they are often
61	not well-supported or restricted (Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
63	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
64	using threads anyway.	61	using threads anyway.
65		62
66	Although the module will work with in the presence of other (Perl-)	63	Although the module will work in the presence of other (Perl-) threads,
67	threads, it is currently not reentrant in any way, so use appropriate	64	it is currently not reentrant in any way, so use appropriate locking
68	locking yourself, always call C<poll_cb> from within the same thread, or	65	yourself, always call C<poll_cb> from within the same thread, or never
69	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
		67
		68	=head2 EXAMPLE
		69
		70	This is a simple example that uses the EV module and loads
		71	F</etc/passwd> asynchronously:
		72
		73	use Fcntl;
		74	use EV;
		75	use IO::AIO;
		76
		77	# register the IO::AIO callback with EV
		78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		79
		80	# queue the request to open /etc/passwd
		81	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		82	my $fh = shift
		83	or die "error while opening: $!";
		84
		85	# stat'ing filehandles is generally non-blocking
		86	my $size = -s $fh;
		87
		88	# queue a request to read the file
		89	my $contents;
		90	aio_read $fh, 0, $size, $contents, 0, sub {
		91	$_[0] == $size
		92	or die "short read: $!";
		93
		94	close $fh;
		95
		96	# file contents now in $contents
		97	print $contents;
		98
		99	# exit event loop and program
		100	EV::unloop;
		101	};
		102	};
		103
		104	# possibly queue up other requests, or open GUI windows,
		105	# check for sockets etc. etc.
		106
		107	# process events as long as there are some:
		108	EV::loop;
70		109
71	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
72		111
73	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
74	directly visible to Perl.	113	directly visible to Perl.
…		…
116	Request has reached the end of its lifetime and holds no resources anymore	155	Request has reached the end of its lifetime and holds no resources anymore
117	(except possibly for the Perl object, but its connection to the actual	156	(except possibly for the Perl object, but its connection to the actual
118	aio request is severed and calling its methods will either do nothing or	157	aio request is severed and calling its methods will either do nothing or
119	result in a runtime error).	158	result in a runtime error).
120		159
		160	=back
		161
121	=cut	162	=cut
122		163
123	package IO::AIO;	164	package IO::AIO;
124		165
125	no warnings;	166	use Carp ();
126	use strict 'vars';	167
		168	use common::sense;
127		169
128	use base 'Exporter';	170	use base 'Exporter';
129		171
130	BEGIN {	172	BEGIN {
131	our $VERSION = '2.0';	173	our $VERSION = '3.6';
132		174
133	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
134	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
136	aio_group aio_nop);	178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		179	aio_rename aio_link aio_move aio_copy aio_group
		180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_statvfs);
		183
137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	184	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	185	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139	min_parallel max_parallel nreqs nready npending);	186	min_parallel max_parallel max_idle
		187	nreqs nready npending nthreads
		188	max_poll_time max_poll_reqs
		189	sendfile fadvise);
		190
		191	push @AIO_REQ, qw(aio_busy); # not exported
140		192
141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	193	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142		194
143	require XSLoader;	195	require XSLoader;
144	XSLoader::load ("IO::AIO", $VERSION);	196	XSLoader::load ("IO::AIO", $VERSION);
145	}	197	}
146		198
147	=head1 FUNCTIONS	199	=head1 FUNCTIONS
148		200
		201	=head2 QUICK OVERVIEW
		202
		203	This section simply lists the prototypes of the most important functions
		204	for quick reference. See the following sections for function-by-function
		205	documentation.
		206
		207	aio_open $pathname, $flags, $mode, $callback->($fh)
		208	aio_close $fh, $callback->($status)
		209	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		210	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		211	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		212	aio_readahead $fh,$offset,$length, $callback->($retval)
		213	aio_stat $fh_or_path, $callback->($status)
		214	aio_lstat $fh, $callback->($status)
		215	aio_statvfs $fh_or_path, $callback->($statvfs)
		216	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		217	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		218	aio_truncate $fh_or_path, $offset, $callback->($status)
		219	aio_chmod $fh_or_path, $mode, $callback->($status)
		220	aio_unlink $pathname, $callback->($status)
		221	aio_mknod $path, $mode, $dev, $callback->($status)
		222	aio_link $srcpath, $dstpath, $callback->($status)
		223	aio_symlink $srcpath, $dstpath, $callback->($status)
		224	aio_readlink $path, $callback->($link)
		225	aio_rename $srcpath, $dstpath, $callback->($status)
		226	aio_mkdir $pathname, $mode, $callback->($status)
		227	aio_rmdir $pathname, $callback->($status)
		228	aio_readdir $pathname, $callback->($entries)
		229	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		230	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		231	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		232	aio_load $path, $data, $callback->($status)
		233	aio_copy $srcpath, $dstpath, $callback->($status)
		234	aio_move $srcpath, $dstpath, $callback->($status)
		235	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		236	aio_rmtree $path, $callback->($status)
		237	aio_sync $callback->($status)
		238	aio_fsync $fh, $callback->($status)
		239	aio_fdatasync $fh, $callback->($status)
		240	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		241	aio_pathsync $path, $callback->($status)
		242	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		243	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		244	aio_group $callback->(...)
		245	aio_nop $callback->()
		246
		247	$prev_pri = aioreq_pri [$pri]
		248	aioreq_nice $pri_adjust
		249
		250	IO::AIO::poll_wait
		251	IO::AIO::poll_cb
		252	IO::AIO::poll
		253	IO::AIO::flush
		254	IO::AIO::max_poll_reqs $nreqs
		255	IO::AIO::max_poll_time $seconds
		256	IO::AIO::min_parallel $nthreads
		257	IO::AIO::max_parallel $nthreads
		258	IO::AIO::max_idle $nthreads
		259	IO::AIO::max_outstanding $maxreqs
		260	IO::AIO::nreqs
		261	IO::AIO::nready
		262	IO::AIO::npending
		263
		264	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		265	IO::AIO::fadvise $fh, $offset, $len, $advice
		266	IO::AIO::mlockall $flags
		267	IO::AIO::munlockall
		268
149	=head2 AIO FUNCTIONS	269	=head2 AIO REQUEST FUNCTIONS
150		270
151	All the C<aio_*> calls are more or less thin wrappers around the syscall	271	All the C<aio_*> calls are more or less thin wrappers around the syscall
152	with the same name (sans C<aio_>). The arguments are similar or identical,	272	with the same name (sans C<aio_>). The arguments are similar or identical,
153	and they all accept an additional (and optional) C<$callback> argument	273	and they all accept an additional (and optional) C<$callback> argument
154	which must be a code reference. This code reference will get called with	274	which must be a code reference. This code reference will get called with
155	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	275	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
156	perl, which usually delivers "false") as it's sole argument when the given	276	perl, which usually delivers "false") as its sole argument after the given
157	syscall has been executed asynchronously.	277	syscall has been executed asynchronously.
158		278
159	All functions expecting a filehandle keep a copy of the filehandle	279	All functions expecting a filehandle keep a copy of the filehandle
160	internally until the request has finished.	280	internally until the request has finished.
161		281
162	All requests return objects of type L<IO::AIO::REQ> that allow further	282	All functions return request objects of type L<IO::AIO::REQ> that allow
163	manipulation of those requests while they are in-flight.	283	further manipulation of those requests while they are in-flight.
164		284
165	The pathnames you pass to these routines I<must> be absolute and	285	The pathnames you pass to these routines I<must> be absolute and
166	encoded in byte form. The reason for the former is that at the time the	286	encoded as octets. The reason for the former is that at the time the
167	request is being executed, the current working directory could have	287	request is being executed, the current working directory could have
168	changed. Alternatively, you can make sure that you never change the	288	changed. Alternatively, you can make sure that you never change the
169	current working directory.	289	current working directory anywhere in the program and then use relative
		290	paths.
170		291
171	To encode pathnames to byte form, either make sure you either: a)	292	To encode pathnames as octets, either make sure you either: a) always pass
172	always pass in filenames you got from outside (command line, readdir	293	in filenames you got from outside (command line, readdir etc.) without
173	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	294	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174	your pathnames to the locale (or other) encoding in effect in the user	295	your pathnames to the locale (or other) encoding in effect in the user
175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	296	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176	use something else.	297	use something else to ensure your scalar has the correct contents.
		298
		299	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		300	handles correctly whether it is set or not.
177		301
178	=over 4	302	=over 4
179		303
180	=item $prev_pri = aioreq_pri [$pri]	304	=item $prev_pri = aioreq_pri [$pri]
181		305
…		…
201	aio_read $_[0], ..., sub {	325	aio_read $_[0], ..., sub {
202	...	326	...
203	};	327	};
204	};	328	};
205		329
		330
206	=item aioreq_nice $pri_adjust	331	=item aioreq_nice $pri_adjust
207		332
208	Similar to C<aioreq_pri>, but subtracts the given value from the current	333	Similar to C<aioreq_pri>, but subtracts the given value from the current
209	priority, so effects are cumulative.	334	priority, so the effect is cumulative.
		335
210		336
211	=item aio_open $pathname, $flags, $mode, $callback->($fh)	337	=item aio_open $pathname, $flags, $mode, $callback->($fh)
212		338
213	Asynchronously open or create a file and call the callback with a newly	339	Asynchronously open or create a file and call the callback with a newly
214	created filehandle for the file.	340	created filehandle for the file.
…		…
220	list. They are the same as used by C<sysopen>.	346	list. They are the same as used by C<sysopen>.
221		347
222	Likewise, C<$mode> specifies the mode of the newly created file, if it	348	Likewise, C<$mode> specifies the mode of the newly created file, if it
223	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	349	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
224	except that it is mandatory (i.e. use C<0> if you don't create new files,	350	except that it is mandatory (i.e. use C<0> if you don't create new files,
225	and C<0666> or C<0777> if you do).	351	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		352	by the umask in effect then the request is being executed, so better never
		353	change the umask.
226		354
227	Example:	355	Example:
228		356
229	aio_open "/etc/passwd", O_RDONLY, 0, sub {	357	aio_open "/etc/passwd", O_RDONLY, 0, sub {
230	if ($_[0]) {	358	if ($_[0]) {
…		…
233	} else {	361	} else {
234	die "open failed: $!\n";	362	die "open failed: $!\n";
235	}	363	}
236	};	364	};
237		365
		366
238	=item aio_close $fh, $callback->($status)	367	=item aio_close $fh, $callback->($status)
239		368
240	Asynchronously close a file and call the callback with the result	369	Asynchronously close a file and call the callback with the result
241	code. I<WARNING:> although accepted, you should not pass in a perl	370	code.
242	filehandle here, as perl will likely close the file descriptor another
243	time when the filehandle is destroyed. Normally, you can safely call perls
244	C<close> or just let filehandles go out of scope.
245		371
246	This is supposed to be a bug in the API, so that might change. It's	372	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247	therefore best to avoid this function.	373	closing the file descriptor associated with the filehandle itself.
		374
		375	Therefore, C<aio_close> will not close the filehandle - instead it will
		376	use dup2 to overwrite the file descriptor with the write-end of a pipe
		377	(the pipe fd will be created on demand and will be cached).
		378
		379	Or in other words: the file descriptor will be closed, but it will not be
		380	free for reuse until the perl filehandle is closed.
		381
		382	=cut
248		383
249	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	384	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250		385
251	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	386	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252		387
253	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	388	Reads or writes C<$length> bytes from or to the specified C<$fh> and
254	into the scalar given by C<data> and offset C<dataoffset> and calls the	389	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
255	callback without the actual number of bytes read (or -1 on error, just	390	and calls the callback without the actual number of bytes read (or -1 on
256	like the syscall).	391	error, just like the syscall).
		392
		393	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		394	offset plus the actual number of bytes read.
		395
		396	If C<$offset> is undefined, then the current file descriptor offset will
		397	be used (and updated), otherwise the file descriptor offset will not be
		398	changed by these calls.
		399
		400	If C<$length> is undefined in C<aio_write>, use the remaining length of
		401	C<$data>.
		402
		403	If C<$dataoffset> is less than zero, it will be counted from the end of
		404	C<$data>.
257		405
258	The C<$data> scalar I<MUST NOT> be modified in any way while the request	406	The C<$data> scalar I<MUST NOT> be modified in any way while the request
259	is outstanding. Modifying it can result in segfaults or WW3 (if the	407	is outstanding. Modifying it can result in segfaults or World War III (if
260	necessary/optional hardware is installed).	408	the necessary/optional hardware is installed).
261		409
262	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	410	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263	offset C<0> within the scalar:	411	offset C<0> within the scalar:
264		412
265	aio_read $fh, 7, 15, $buffer, 0, sub {	413	aio_read $fh, 7, 15, $buffer, 0, sub {
266	$_[0] > 0 or die "read error: $!";	414	$_[0] > 0 or die "read error: $!";
267	print "read $_[0] bytes: <$buffer>\n";	415	print "read $_[0] bytes: <$buffer>\n";
268	};	416	};
269		417
270	=item aio_move $srcpath, $dstpath, $callback->($status)
271
272	Try to move the I<file> (directories not supported as either source or
273	destination) from C<$srcpath> to C<$dstpath> and call the callback with
274	the C<0> (error) or C<-1> ok.
275
276	This is a composite request that tries to rename(2) the file first. If
277	rename files with C<EXDEV>, it creates the destination file with mode 0200
278	and copies the contents of the source file into it using C<aio_sendfile>,
279	followed by restoring atime, mtime, access mode and uid/gid, in that
280	order, and unlinking the C<$srcpath>.
281
282	If an error occurs, the partial destination file will be unlinked, if
283	possible, except when setting atime, mtime, access mode and uid/gid, where
284	errors are being ignored.
285
286	=cut
287
288	sub aio_move($$$) {
289	my ($src, $dst, $cb) = @_;
290
291	my $pri = aioreq_pri;
292	my $grp = aio_group $cb;
293
294	aioreq_pri $pri;
295	add $grp aio_rename $src, $dst, sub {
296	if ($_[0] && $! == EXDEV) {
297	aioreq_pri $pri;
298	add $grp aio_open $src, O_RDONLY, 0, sub {
299	if (my $src_fh = $_[0]) {
300	my @stat = stat $src_fh;
301
302	aioreq_pri $pri;
303	add $grp aio_open $dst, O_WRONLY, 0200, sub {
304	if (my $dst_fh = $_[0]) {
305	aioreq_pri $pri;
306	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
307	close $src_fh;
308
309	if ($_[0] == $stat[7]) {
310	utime $stat[8], $stat[9], $dst;
311	chmod $stat[2] & 07777, $dst_fh;
312	chown $stat[4], $stat[5], $dst_fh;
313	close $dst_fh;
314
315	aioreq_pri $pri;
316	add $grp aio_unlink $src, sub {
317	$grp->result ($_[0]);
318	};
319	} else {
320	my $errno = $!;
321	aioreq_pri $pri;
322	add $grp aio_unlink $dst, sub {
323	$! = $errno;
324	$grp->result (-1);
325	};
326	}
327	};
328	} else {
329	$grp->result (-1);
330	}
331	},
332
333	} else {
334	$grp->result (-1);
335	}
336	};
337	} else {
338	$grp->result ($_[0]);
339	}
340	};
341
342	$grp
343	}
344		418
345	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	419	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
346		420
347	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	421	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
348	reading at byte offset C<$in_offset>, and starts writing at the current	422	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
350	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	424	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
351	other.	425	other.
352		426
353	This call tries to make use of a native C<sendfile> syscall to provide	427	This call tries to make use of a native C<sendfile> syscall to provide
354	zero-copy operation. For this to work, C<$out_fh> should refer to a	428	zero-copy operation. For this to work, C<$out_fh> should refer to a
355	socket, and C<$in_fh> should refer to mmap'able file.	429	socket, and C<$in_fh> should refer to an mmap'able file.
356		430
357	If the native sendfile call fails or is not implemented, it will be	431	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		432	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
358	emulated, so you can call C<aio_sendfile> on any type of filehandle	433	it will be emulated, so you can call C<aio_sendfile> on any type of
359	regardless of the limitations of the operating system.	434	filehandle regardless of the limitations of the operating system.
360		435
361	Please note, however, that C<aio_sendfile> can read more bytes from	436	Please note, however, that C<aio_sendfile> can read more bytes from
362	C<$in_fh> than are written, and there is no way to find out how many	437	C<$in_fh> than are written, and there is no way to find out how many
363	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	438	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
364	provides the number of bytes written to C<$out_fh>. Only if the result	439	provides the number of bytes written to C<$out_fh>. Only if the result
365	value equals C<$length> one can assume that C<$length> bytes have been	440	value equals C<$length> one can assume that C<$length> bytes have been
366	read.	441	read.
		442
367		443
368	=item aio_readahead $fh,$offset,$length, $callback->($retval)	444	=item aio_readahead $fh,$offset,$length, $callback->($retval)
369		445
370	C<aio_readahead> populates the page cache with data from a file so that	446	C<aio_readahead> populates the page cache with data from a file so that
371	subsequent reads from that file will not block on disk I/O. The C<$offset>	447	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
377	file. The current file offset of the file is left unchanged.	453	file. The current file offset of the file is left unchanged.
378		454
379	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	455	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
380	emulated by simply reading the data, which would have a similar effect.	456	emulated by simply reading the data, which would have a similar effect.
381		457
		458
382	=item aio_stat $fh_or_path, $callback->($status)	459	=item aio_stat $fh_or_path, $callback->($status)
383		460
384	=item aio_lstat $fh, $callback->($status)	461	=item aio_lstat $fh, $callback->($status)
385		462
386	Works like perl's C<stat> or C<lstat> in void context. The callback will	463	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
399	aio_stat "/etc/passwd", sub {	476	aio_stat "/etc/passwd", sub {
400	$_[0] and die "stat failed: $!";	477	$_[0] and die "stat failed: $!";
401	print "size is ", -s _, "\n";	478	print "size is ", -s _, "\n";
402	};	479	};
403		480
		481
		482	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		483
		484	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		485	whether a file handle or path was passed.
		486
		487	On success, the callback is passed a hash reference with the following
		488	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		489	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		490	is passed.
		491
		492	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		493	C<ST_NOSUID>.
		494
		495	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		496	their correct value when available, or to C<0> on systems that do
		497	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		498	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		499	C<ST_NODIRATIME> and C<ST_RELATIME>.
		500
		501	Example: stat C</wd> and dump out the data if successful.
		502
		503	aio_statvfs "/wd", sub {
		504	my $f = $_[0]
		505	or die "statvfs: $!";
		506
		507	use Data::Dumper;
		508	say Dumper $f;
		509	};
		510
		511	# result:
		512	{
		513	bsize => 1024,
		514	bfree => 4333064312,
		515	blocks => 10253828096,
		516	files => 2050765568,
		517	flag => 4096,
		518	favail => 2042092649,
		519	bavail => 4333064312,
		520	ffree => 2042092649,
		521	namemax => 255,
		522	frsize => 1024,
		523	fsid => 1810
		524	}
		525
		526
		527	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		528
		529	Works like perl's C<utime> function (including the special case of $atime
		530	and $mtime being undef). Fractional times are supported if the underlying
		531	syscalls support them.
		532
		533	When called with a pathname, uses utimes(2) if available, otherwise
		534	utime(2). If called on a file descriptor, uses futimes(2) if available,
		535	otherwise returns ENOSYS, so this is not portable.
		536
		537	Examples:
		538
		539	# set atime and mtime to current time (basically touch(1)):
		540	aio_utime "path", undef, undef;
		541	# set atime to current time and mtime to beginning of the epoch:
		542	aio_utime "path", time, undef; # undef==0
		543
		544
		545	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		546
		547	Works like perl's C<chown> function, except that C<undef> for either $uid
		548	or $gid is being interpreted as "do not change" (but -1 can also be used).
		549
		550	Examples:
		551
		552	# same as "chown root path" in the shell:
		553	aio_chown "path", 0, -1;
		554	# same as above:
		555	aio_chown "path", 0, undef;
		556
		557
		558	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		559
		560	Works like truncate(2) or ftruncate(2).
		561
		562
		563	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		564
		565	Works like perl's C<chmod> function.
		566
		567
404	=item aio_unlink $pathname, $callback->($status)	568	=item aio_unlink $pathname, $callback->($status)
405		569
406	Asynchronously unlink (delete) a file and call the callback with the	570	Asynchronously unlink (delete) a file and call the callback with the
407	result code.	571	result code.
408		572
		573
		574	=item aio_mknod $path, $mode, $dev, $callback->($status)
		575
		576	[EXPERIMENTAL]
		577
		578	Asynchronously create a device node (or fifo). See mknod(2).
		579
		580	The only (POSIX-) portable way of calling this function is:
		581
		582	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		583
		584
409	=item aio_link $srcpath, $dstpath, $callback->($status)	585	=item aio_link $srcpath, $dstpath, $callback->($status)
410		586
411	Asynchronously create a new link to the existing object at C<$srcpath> at	587	Asynchronously create a new link to the existing object at C<$srcpath> at
412	the path C<$dstpath> and call the callback with the result code.	588	the path C<$dstpath> and call the callback with the result code.
413		589
		590
414	=item aio_symlink $srcpath, $dstpath, $callback->($status)	591	=item aio_symlink $srcpath, $dstpath, $callback->($status)
415		592
416	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	593	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
417	the path C<$dstpath> and call the callback with the result code.	594	the path C<$dstpath> and call the callback with the result code.
418		595
		596
		597	=item aio_readlink $path, $callback->($link)
		598
		599	Asynchronously read the symlink specified by C<$path> and pass it to
		600	the callback. If an error occurs, nothing or undef gets passed to the
		601	callback.
		602
		603
419	=item aio_rename $srcpath, $dstpath, $callback->($status)	604	=item aio_rename $srcpath, $dstpath, $callback->($status)
420		605
421	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	606	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422	rename(2) and call the callback with the result code.	607	rename(2) and call the callback with the result code.
423		608
		609
		610	=item aio_mkdir $pathname, $mode, $callback->($status)
		611
		612	Asynchronously mkdir (create) a directory and call the callback with
		613	the result code. C<$mode> will be modified by the umask at the time the
		614	request is executed, so do not change your umask.
		615
		616
424	=item aio_rmdir $pathname, $callback->($status)	617	=item aio_rmdir $pathname, $callback->($status)
425		618
426	Asynchronously rmdir (delete) a directory and call the callback with the	619	Asynchronously rmdir (delete) a directory and call the callback with the
427	result code.	620	result code.
		621
428		622
429	=item aio_readdir $pathname, $callback->($entries)	623	=item aio_readdir $pathname, $callback->($entries)
430		624
431	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	625	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432	directory (i.e. opendir + readdir + closedir). The entries will not be	626	directory (i.e. opendir + readdir + closedir). The entries will not be
433	sorted, and will B<NOT> include the C<.> and C<..> entries.	627	sorted, and will B<NOT> include the C<.> and C<..> entries.
434		628
435	The callback a single argument which is either C<undef> or an array-ref	629	The callback is passed a single argument which is either C<undef> or an
436	with the filenames.	630	array-ref with the filenames.
		631
		632
		633	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		634
		635	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		636	behaviour and output format. In case of an error, C<$entries> will be
		637	C<undef>.
		638
		639	The flags are a combination of the following constants, ORed together (the
		640	flags will also be passed to the callback, possibly modified):
		641
		642	=over 4
		643
		644	=item IO::AIO::READDIR_DENTS
		645
		646	When this flag is off, then the callback gets an arrayref with of names
		647	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		648	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		649	entry in more detail.
		650
		651	C<$name> is the name of the entry.
		652
		653	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		654
		655	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		656	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		657	C<IO::AIO::DT_WHT>.
		658
		659	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		660	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		661	scalars are read-only: you can not modify them.
		662
		663	C<$inode> is the inode number (which might not be exact on systems with 64
		664	bit inode numbers and 32 bit perls). This field has unspecified content on
		665	systems that do not deliver the inode information.
		666
		667	=item IO::AIO::READDIR_DIRS_FIRST
		668
		669	When this flag is set, then the names will be returned in an order where
		670	likely directories come first. This is useful when you need to quickly
		671	find directories, or you want to find all directories while avoiding to
		672	stat() each entry.
		673
		674	If the system returns type information in readdir, then this is used
		675	to find directories directly. Otherwise, likely directories are files
		676	beginning with ".", or otherwise files with no dots, of which files with
		677	short names are tried first.
		678
		679	=item IO::AIO::READDIR_STAT_ORDER
		680
		681	When this flag is set, then the names will be returned in an order
		682	suitable for stat()'ing each one. That is, when you plan to stat()
		683	all files in the given directory, then the returned order will likely
		684	be fastest.
		685
		686	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		687	the likely dirs come first, resulting in a less optimal stat order.
		688
		689	=item IO::AIO::READDIR_FOUND_UNKNOWN
		690
		691	This flag should not be set when calling C<aio_readdirx>. Instead, it
		692	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		693	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		694	C<$type>'s are known, which can be used to speed up some algorithms.
		695
		696	=back
		697
		698
		699	=item aio_load $path, $data, $callback->($status)
		700
		701	This is a composite request that tries to fully load the given file into
		702	memory. Status is the same as with aio_read.
		703
		704	=cut
		705
		706	sub aio_load($$;$) {
		707	my ($path, undef, $cb) = @_;
		708	my $data = \$_[1];
		709
		710	my $pri = aioreq_pri;
		711	my $grp = aio_group $cb;
		712
		713	aioreq_pri $pri;
		714	add $grp aio_open $path, O_RDONLY, 0, sub {
		715	my $fh = shift
		716	or return $grp->result (-1);
		717
		718	aioreq_pri $pri;
		719	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		720	$grp->result ($_[0]);
		721	};
		722	};
		723
		724	$grp
		725	}
		726
		727	=item aio_copy $srcpath, $dstpath, $callback->($status)
		728
		729	Try to copy the I<file> (directories not supported as either source or
		730	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		731	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		732
		733	This is a composite request that creates the destination file with
		734	mode 0200 and copies the contents of the source file into it using
		735	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		736	uid/gid, in that order.
		737
		738	If an error occurs, the partial destination file will be unlinked, if
		739	possible, except when setting atime, mtime, access mode and uid/gid, where
		740	errors are being ignored.
		741
		742	=cut
		743
		744	sub aio_copy($$;$) {
		745	my ($src, $dst, $cb) = @_;
		746
		747	my $pri = aioreq_pri;
		748	my $grp = aio_group $cb;
		749
		750	aioreq_pri $pri;
		751	add $grp aio_open $src, O_RDONLY, 0, sub {
		752	if (my $src_fh = $_[0]) {
		753	my @stat = stat $src_fh; # hmm, might block over nfs?
		754
		755	aioreq_pri $pri;
		756	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
		757	if (my $dst_fh = $_[0]) {
		758	aioreq_pri $pri;
		759	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		760	if ($_[0] == $stat[7]) {
		761	$grp->result (0);
		762	close $src_fh;
		763
		764	my $ch = sub {
		765	aioreq_pri $pri;
		766	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		767	aioreq_pri $pri;
		768	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		769	aioreq_pri $pri;
		770	add $grp aio_close $dst_fh;
		771	}
		772	};
		773	};
		774
		775	aioreq_pri $pri;
		776	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		777	if ($_[0] < 0 && $! == ENOSYS) {
		778	aioreq_pri $pri;
		779	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		780	} else {
		781	$ch->();
		782	}
		783	};
		784	} else {
		785	$grp->result (-1);
		786	close $src_fh;
		787	close $dst_fh;
		788
		789	aioreq $pri;
		790	add $grp aio_unlink $dst;
		791	}
		792	};
		793	} else {
		794	$grp->result (-1);
		795	}
		796	},
		797
		798	} else {
		799	$grp->result (-1);
		800	}
		801	};
		802
		803	$grp
		804	}
		805
		806	=item aio_move $srcpath, $dstpath, $callback->($status)
		807
		808	Try to move the I<file> (directories not supported as either source or
		809	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		810	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		811
		812	This is a composite request that tries to rename(2) the file first; if
		813	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
		814	that is successful, unlinks the C<$srcpath>.
		815
		816	=cut
		817
		818	sub aio_move($$;$) {
		819	my ($src, $dst, $cb) = @_;
		820
		821	my $pri = aioreq_pri;
		822	my $grp = aio_group $cb;
		823
		824	aioreq_pri $pri;
		825	add $grp aio_rename $src, $dst, sub {
		826	if ($_[0] && $! == EXDEV) {
		827	aioreq_pri $pri;
		828	add $grp aio_copy $src, $dst, sub {
		829	$grp->result ($_[0]);
		830
		831	if (!$_[0]) {
		832	aioreq_pri $pri;
		833	add $grp aio_unlink $src;
		834	}
		835	};
		836	} else {
		837	$grp->result ($_[0]);
		838	}
		839	};
		840
		841	$grp
		842	}
437		843
438	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	844	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439		845
440	Scans a directory (similar to C<aio_readdir>) but additionally tries to	846	Scans a directory (similar to C<aio_readdir>) but additionally tries to
441	efficiently separate the entries of directory C<$path> into two sets of	847	efficiently separate the entries of directory C<$path> into two sets of
…		…
460		866
461	Implementation notes.	867	Implementation notes.
462		868
463	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	869	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
464		870
		871	If readdir returns file type information, then this is used directly to
		872	find directories.
		873
465	After reading the directory, the modification time, size etc. of the	874	Otherwise, after reading the directory, the modification time, size etc.
466	directory before and after the readdir is checked, and if they match (and	875	of the directory before and after the readdir is checked, and if they
467	isn't the current time), the link count will be used to decide how many	876	match (and isn't the current time), the link count will be used to decide
468	entries are directories (if >= 2). Otherwise, no knowledge of the number	877	how many entries are directories (if >= 2). Otherwise, no knowledge of the
469	of subdirectories will be assumed.	878	number of subdirectories will be assumed.
470		879
471	Then entries will be sorted into likely directories (everything without	880	Then entries will be sorted into likely directories a non-initial dot
472	a non-initial dot currently) and likely non-directories (everything	881	currently) and likely non-directories (see C<aio_readdirx>). Then every
473	else). Then every entry plus an appended C</.> will be C<stat>'ed,	882	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
474	likely directories first. If that succeeds, it assumes that the entry	883	in order of their inode numbers. If that succeeds, it assumes that the
475	is a directory or a symlink to directory (which will be checked	884	entry is a directory or a symlink to directory (which will be checked
476	seperately). This is often faster than stat'ing the entry itself because	885	seperately). This is often faster than stat'ing the entry itself because
477	filesystems might detect the type of the entry without reading the inode	886	filesystems might detect the type of the entry without reading the inode
478	data (e.g. ext2fs filetype feature).	887	data (e.g. ext2fs filetype feature), even on systems that cannot return
		888	the filetype information on readdir.
479		889
480	If the known number of directories (link count - 2) has been reached, the	890	If the known number of directories (link count - 2) has been reached, the
481	rest of the entries is assumed to be non-directories.	891	rest of the entries is assumed to be non-directories.
482		892
483	This only works with certainty on POSIX (= UNIX) filesystems, which	893	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
487	as those tend to return 0 or 1 as link counts, which disables the	897	as those tend to return 0 or 1 as link counts, which disables the
488	directory counting heuristic.	898	directory counting heuristic.
489		899
490	=cut	900	=cut
491		901
492	sub aio_scandir($$$) {	902	sub aio_scandir($$;$) {
493	my ($path, $maxreq, $cb) = @_;	903	my ($path, $maxreq, $cb) = @_;
494		904
495	my $pri = aioreq_pri;	905	my $pri = aioreq_pri;
496		906
497	my $grp = aio_group $cb;	907	my $grp = aio_group $cb;
…		…
505	my $now = time;	915	my $now = time;
506	my $hash1 = join ":", (stat _)[0,1,3,7,9];	916	my $hash1 = join ":", (stat _)[0,1,3,7,9];
507		917
508	# read the directory entries	918	# read the directory entries
509	aioreq_pri $pri;	919	aioreq_pri $pri;
510	add $grp aio_readdir $path, sub {	920	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
511	my $entries = shift	921	my $entries = shift
512	or return $grp->result ();	922	or return $grp->result ();
513		923
514	# stat the dir another time	924	# stat the dir another time
515	aioreq_pri $pri;	925	aioreq_pri $pri;
…		…
521	# take the slow route if anything looks fishy	931	# take the slow route if anything looks fishy
522	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	932	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
523	$ndirs = -1;	933	$ndirs = -1;
524	} else {	934	} else {
525	# if nlink == 2, we are finished	935	# if nlink == 2, we are finished
526	# on non-posix-fs's, we rely on nlink < 2	936	# for non-posix-fs's, we rely on nlink < 2
527	$ndirs = (stat _)[3] - 2	937	$ndirs = (stat _)[3] - 2
528	or return $grp->result ([], $entries);	938	or return $grp->result ([], $entries);
529	}	939	}
530		940
531	# sort into likely dirs and likely nondirs
532	# dirs == files without ".", short entries first
533	$entries = [map $_->[0],
534	sort { $b->[1] cmp $a->[1] }
535	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
536	@$entries];
537
538	my (@dirs, @nondirs);	941	my (@dirs, @nondirs);
539		942
540	my $statgrp = add $grp aio_group sub {	943	my $statgrp = add $grp aio_group sub {
541	$grp->result (\@dirs, \@nondirs);	944	$grp->result (\@dirs, \@nondirs);
542	};	945	};
543		946
544	limit $statgrp $maxreq;	947	limit $statgrp $maxreq;
545	feed $statgrp sub {	948	feed $statgrp sub {
546	return unless @$entries;	949	return unless @$entries;
547	my $entry = pop @$entries;	950	my $entry = shift @$entries;
548		951
549	aioreq_pri $pri;	952	aioreq_pri $pri;
550	add $statgrp aio_stat "$path/$entry/.", sub {	953	add $statgrp aio_stat "$path/$entry/.", sub {
551	if ($_[0] < 0) {	954	if ($_[0] < 0) {
552	push @nondirs, $entry;	955	push @nondirs, $entry;
…		…
573	};	976	};
574		977
575	$grp	978	$grp
576	}	979	}
577		980
		981	=item aio_rmtree $path, $callback->($status)
		982
		983	Delete a directory tree starting (and including) C<$path>, return the
		984	status of the final C<rmdir> only. This is a composite request that
		985	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		986	everything else.
		987
		988	=cut
		989
		990	sub aio_rmtree;
		991	sub aio_rmtree($;$) {
		992	my ($path, $cb) = @_;
		993
		994	my $pri = aioreq_pri;
		995	my $grp = aio_group $cb;
		996
		997	aioreq_pri $pri;
		998	add $grp aio_scandir $path, 0, sub {
		999	my ($dirs, $nondirs) = @_;
		1000
		1001	my $dirgrp = aio_group sub {
		1002	add $grp aio_rmdir $path, sub {
		1003	$grp->result ($_[0]);
		1004	};
		1005	};
		1006
		1007	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1008	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1009
		1010	add $grp $dirgrp;
		1011	};
		1012
		1013	$grp
		1014	}
		1015
		1016	=item aio_sync $callback->($status)
		1017
		1018	Asynchronously call sync and call the callback when finished.
		1019
578	=item aio_fsync $fh, $callback->($status)	1020	=item aio_fsync $fh, $callback->($status)
579		1021
580	Asynchronously call fsync on the given filehandle and call the callback	1022	Asynchronously call fsync on the given filehandle and call the callback
581	with the fsync result code.	1023	with the fsync result code.
582		1024
…		…
585	Asynchronously call fdatasync on the given filehandle and call the	1027	Asynchronously call fdatasync on the given filehandle and call the
586	callback with the fdatasync result code.	1028	callback with the fdatasync result code.
587		1029
588	If this call isn't available because your OS lacks it or it couldn't be	1030	If this call isn't available because your OS lacks it or it couldn't be
589	detected, it will be emulated by calling C<fsync> instead.	1031	detected, it will be emulated by calling C<fsync> instead.
		1032
		1033	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1034
		1035	Sync the data portion of the file specified by C<$offset> and C<$length>
		1036	to disk (but NOT the metadata), by calling the Linux-specific
		1037	sync_file_range call. If sync_file_range is not available or it returns
		1038	ENOSYS, then fdatasync or fsync is being substituted.
		1039
		1040	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1041	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1042	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1043	manpage for details.
		1044
		1045	=item aio_pathsync $path, $callback->($status)
		1046
		1047	This request tries to open, fsync and close the given path. This is a
		1048	composite request intended to sync directories after directory operations
		1049	(E.g. rename). This might not work on all operating systems or have any
		1050	specific effect, but usually it makes sure that directory changes get
		1051	written to disc. It works for anything that can be opened for read-only,
		1052	not just directories.
		1053
		1054	Future versions of this function might fall back to other methods when
		1055	C<fsync> on the directory fails (such as calling C<sync>).
		1056
		1057	Passes C<0> when everything went ok, and C<-1> on error.
		1058
		1059	=cut
		1060
		1061	sub aio_pathsync($;$) {
		1062	my ($path, $cb) = @_;
		1063
		1064	my $pri = aioreq_pri;
		1065	my $grp = aio_group $cb;
		1066
		1067	aioreq_pri $pri;
		1068	add $grp aio_open $path, O_RDONLY, 0, sub {
		1069	my ($fh) = @_;
		1070	if ($fh) {
		1071	aioreq_pri $pri;
		1072	add $grp aio_fsync $fh, sub {
		1073	$grp->result ($_[0]);
		1074
		1075	aioreq_pri $pri;
		1076	add $grp aio_close $fh;
		1077	};
		1078	} else {
		1079	$grp->result (-1);
		1080	}
		1081	};
		1082
		1083	$grp
		1084	}
		1085
		1086	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1087
		1088	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1089	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1090	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1091	scalar must only be modified in-place while an aio operation is pending on
		1092	it).
		1093
		1094	It calls the C<msync> function of your OS, if available, with the memory
		1095	area starting at C<$offset> in the string and ending C<$length> bytes
		1096	later. If C<$length> is negative, counts from the end, and if C<$length>
		1097	is C<undef>, then it goes till the end of the string. The flags can be
		1098	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1099	C<IO::AIO::MS_SYNC>.
		1100
		1101	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1102
		1103	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1104	scalars.
		1105
		1106	It touches (reads or writes) all memory pages in the specified
		1107	range inside the scalar. All caveats and parameters are the same
		1108	as for C<aio_msync>, above, except for flags, which must be either
		1109	C<0> (which reads all pages and ensures they are instantiated) or
		1110	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1111	writing an octet from it, which dirties the page).
590		1112
591	=item aio_group $callback->(...)	1113	=item aio_group $callback->(...)
592		1114
593	This is a very special aio request: Instead of doing something, it is a	1115	This is a very special aio request: Instead of doing something, it is a
594	container for other aio requests, which is useful if you want to bundle	1116	container for other aio requests, which is useful if you want to bundle
…		…
644	=item cancel $req	1166	=item cancel $req
645		1167
646	Cancels the request, if possible. Has the effect of skipping execution	1168	Cancels the request, if possible. Has the effect of skipping execution
647	when entering the B<execute> state and skipping calling the callback when	1169	when entering the B<execute> state and skipping calling the callback when
648	entering the the B<result> state, but will leave the request otherwise	1170	entering the the B<result> state, but will leave the request otherwise
649	untouched. That means that requests that currently execute will not be	1171	untouched (with the exception of readdir). That means that requests that
650	stopped and resources held by the request will not be freed prematurely.	1172	currently execute will not be stopped and resources held by the request
		1173	will not be freed prematurely.
651		1174
652	=item cb $req $callback->(...)	1175	=item cb $req $callback->(...)
653		1176
654	Replace (or simply set) the callback registered to the request.	1177	Replace (or simply set) the callback registered to the request.
655		1178
…		…
706	Their lifetime, simplified, looks like this: when they are empty, they	1229	Their lifetime, simplified, looks like this: when they are empty, they
707	will finish very quickly. If they contain only requests that are in the	1230	will finish very quickly. If they contain only requests that are in the
708	C<done> state, they will also finish. Otherwise they will continue to	1231	C<done> state, they will also finish. Otherwise they will continue to
709	exist.	1232	exist.
710		1233
711	That means after creating a group you have some time to add requests. And	1234	That means after creating a group you have some time to add requests
712	in the callbacks of those requests, you can add further requests to the	1235	(precisely before the callback has been invoked, which is only done within
713	group. And only when all those requests have finished will the the group	1236	the C<poll_cb>). And in the callbacks of those requests, you can add
714	itself finish.	1237	further requests to the group. And only when all those requests have
		1238	finished will the the group itself finish.
715		1239
716	=over 4	1240	=over 4
717		1241
718	=item add $grp ...	1242	=item add $grp ...
719		1243
…		…
728	=item $grp->cancel_subs	1252	=item $grp->cancel_subs
729		1253
730	Cancel all subrequests and clears any feeder, but not the group request	1254	Cancel all subrequests and clears any feeder, but not the group request
731	itself. Useful when you queued a lot of events but got a result early.	1255	itself. Useful when you queued a lot of events but got a result early.
732		1256
		1257	The group request will finish normally (you cannot add requests to the
		1258	group).
		1259
733	=item $grp->result (...)	1260	=item $grp->result (...)
734		1261
735	Set the result value(s) that will be passed to the group callback when all	1262	Set the result value(s) that will be passed to the group callback when all
736	subrequests have finished and set thre groups errno to the current value	1263	subrequests have finished and set the groups errno to the current value
737	of errno (just like calling C<errno> without an error number). By default,	1264	of errno (just like calling C<errno> without an error number). By default,
738	no argument will be passed and errno is zero.	1265	no argument will be passed and errno is zero.
739		1266
740	=item $grp->errno ([$errno])	1267	=item $grp->errno ([$errno])
741		1268
…		…
752	=item feed $grp $callback->($grp)	1279	=item feed $grp $callback->($grp)
753		1280
754	Sets a feeder/generator on this group: every group can have an attached	1281	Sets a feeder/generator on this group: every group can have an attached
755	generator that generates requests if idle. The idea behind this is that,	1282	generator that generates requests if idle. The idea behind this is that,
756	although you could just queue as many requests as you want in a group,	1283	although you could just queue as many requests as you want in a group,
757	this might starve other requests for a potentially long time. For	1284	this might starve other requests for a potentially long time. For example,
758	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1285	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
759	requests, delaying any later requests for a long time.	1286	delaying any later requests for a long time.
760		1287
761	To avoid this, and allow incremental generation of requests, you can	1288	To avoid this, and allow incremental generation of requests, you can
762	instead a group and set a feeder on it that generates those requests. The	1289	instead a group and set a feeder on it that generates those requests. The
763	feed callback will be called whenever there are few enough (see C<limit>,	1290	feed callback will be called whenever there are few enough (see C<limit>,
764	below) requests active in the group itself and is expected to queue more	1291	below) requests active in the group itself and is expected to queue more
…		…
768	not impose any limits).	1295	not impose any limits).
769		1296
770	If the feed does not queue more requests when called, it will be	1297	If the feed does not queue more requests when called, it will be
771	automatically removed from the group.	1298	automatically removed from the group.
772		1299
773	If the feed limit is C<0>, it will be set to C<2> automatically.	1300	If the feed limit is C<0> when this method is called, it will be set to
		1301	C<2> automatically.
774		1302
775	Example:	1303	Example:
776		1304
777	# stat all files in @files, but only ever use four aio requests concurrently:	1305	# stat all files in @files, but only ever use four aio requests concurrently:
778		1306
…		…
790	Sets the feeder limit for the group: The feeder will be called whenever	1318	Sets the feeder limit for the group: The feeder will be called whenever
791	the group contains less than this many requests.	1319	the group contains less than this many requests.
792		1320
793	Setting the limit to C<0> will pause the feeding process.	1321	Setting the limit to C<0> will pause the feeding process.
794		1322
		1323	The default value for the limit is C<0>, but note that setting a feeder
		1324	automatically bumps it up to C<2>.
		1325
795	=back	1326	=back
796		1327
797	=head2 SUPPORT FUNCTIONS	1328	=head2 SUPPORT FUNCTIONS
798		1329
		1330	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		1331
799	=over 4	1332	=over 4
800		1333
801	=item $fileno = IO::AIO::poll_fileno	1334	=item $fileno = IO::AIO::poll_fileno
802		1335
803	Return the I<request result pipe file descriptor>. This filehandle must be	1336	Return the I<request result pipe file descriptor>. This filehandle must be
804	polled for reading by some mechanism outside this module (e.g. Event or	1337	polled for reading by some mechanism outside this module (e.g. EV, Glib,
805	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1338	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
806	to call C<poll_cb> to check the results.	1339	you have to call C<poll_cb> to check the results.
807		1340
808	See C<poll_cb> for an example.	1341	See C<poll_cb> for an example.
809		1342
810	=item IO::AIO::poll_cb	1343	=item IO::AIO::poll_cb
811		1344
812	Process all outstanding events on the result pipe. You have to call this	1345	Process some outstanding events on the result pipe. You have to call this
813	regularly. Returns the number of events processed. Returns immediately	1346	regularly. Returns C<0> if all events could be processed, or C<-1> if it
814	when no events are outstanding.	1347	returned earlier for whatever reason. Returns immediately when no events
		1348	are outstanding. The amount of events processed depends on the settings of
		1349	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815		1350
816	If not all requests were processed for whatever reason, the filehandle	1351	If not all requests were processed for whatever reason, the filehandle
817	will still be ready when C<poll_cb> returns.	1352	will still be ready when C<poll_cb> returns, so normally you don't have to
		1353	do anything special to have it called later.
818		1354
819	Example: Install an Event watcher that automatically calls	1355	Example: Install an Event watcher that automatically calls
820	IO::AIO::poll_cb with high priority:	1356	IO::AIO::poll_cb with high priority (more examples can be found in the
		1357	SYNOPSIS section, at the top of this document):
821		1358
822	Event->io (fd => IO::AIO::poll_fileno,	1359	Event->io (fd => IO::AIO::poll_fileno,
823	poll => 'r', async => 1,	1360	poll => 'r', async => 1,
824	cb => \&IO::AIO::poll_cb);	1361	cb => \&IO::AIO::poll_cb);
825		1362
826	=item IO::AIO::poll_some $max_requests	1363	=item IO::AIO::poll_wait
827		1364
828	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests	1365	If there are any outstanding requests and none of them in the result
829	at a time.	1366	phase, wait till the result filehandle becomes ready for reading (simply
		1367	does a C<select> on the filehandle. This is useful if you want to
		1368	synchronously wait for some requests to finish).
830		1369
831	Useful if you want to ensure some level of interactiveness when perl is	1370	See C<nreqs> for an example.
832	not fast enough to process all requests in time.	1371
		1372	=item IO::AIO::poll
		1373
		1374	Waits until some requests have been handled.
		1375
		1376	Returns the number of requests processed, but is otherwise strictly
		1377	equivalent to:
		1378
		1379	IO::AIO::poll_wait, IO::AIO::poll_cb
		1380
		1381	=item IO::AIO::flush
		1382
		1383	Wait till all outstanding AIO requests have been handled.
		1384
		1385	Strictly equivalent to:
		1386
		1387	IO::AIO::poll_wait, IO::AIO::poll_cb
		1388	while IO::AIO::nreqs;
		1389
		1390	=item IO::AIO::max_poll_reqs $nreqs
		1391
		1392	=item IO::AIO::max_poll_time $seconds
		1393
		1394	These set the maximum number of requests (default C<0>, meaning infinity)
		1395	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1396	the maximum amount of time (default C<0>, meaning infinity) spent in
		1397	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1398	of time C<poll_cb> is allowed to use).
		1399
		1400	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1401	syscall per request processed, which is not normally a problem unless your
		1402	callbacks are really really fast or your OS is really really slow (I am
		1403	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1404
		1405	Setting these is useful if you want to ensure some level of
		1406	interactiveness when perl is not fast enough to process all requests in
		1407	time.
		1408
		1409	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833		1410
834	Example: Install an Event watcher that automatically calls	1411	Example: Install an Event watcher that automatically calls
835	IO::AIO::poll_some with low priority, to ensure that other parts of the	1412	IO::AIO::poll_cb with low priority, to ensure that other parts of the
836	program get the CPU sometimes even under high AIO load.	1413	program get the CPU sometimes even under high AIO load.
837		1414
		1415	# try not to spend much more than 0.1s in poll_cb
		1416	IO::AIO::max_poll_time 0.1;
		1417
		1418	# use a low priority so other tasks have priority
838	Event->io (fd => IO::AIO::poll_fileno,	1419	Event->io (fd => IO::AIO::poll_fileno,
839	poll => 'r', nice => 1,	1420	poll => 'r', nice => 1,
840	cb => sub { IO::AIO::poll_some 256 });	1421	cb => &IO::AIO::poll_cb);
841		1422
842	=item IO::AIO::poll_wait	1423	=back
843		1424
844	Wait till the result filehandle becomes ready for reading (simply does a	1425	=head3 CONTROLLING THE NUMBER OF THREADS
845	C<select> on the filehandle. This is useful if you want to synchronously wait
846	for some requests to finish).
847		1426
848	See C<nreqs> for an example.	1427	=over
849
850	=item IO::AIO::nreqs
851
852	Returns the number of requests currently in the ready, execute or pending
853	states (i.e. for which their callback has not been invoked yet).
854
855	Example: wait till there are no outstanding requests anymore:
856
857	IO::AIO::poll_wait, IO::AIO::poll_cb
858	while IO::AIO::nreqs;
859
860	=item IO::AIO::nready
861
862	Returns the number of requests currently in the ready state (not yet
863	executed).
864
865	=item IO::AIO::npending
866
867	Returns the number of requests currently in the pending state (executed,
868	but not yet processed by poll_cb).
869
870	=item IO::AIO::flush
871
872	Wait till all outstanding AIO requests have been handled.
873
874	Strictly equivalent to:
875
876	IO::AIO::poll_wait, IO::AIO::poll_cb
877	while IO::AIO::nreqs;
878
879	=item IO::AIO::poll
880
881	Waits until some requests have been handled.
882
883	Strictly equivalent to:
884
885	IO::AIO::poll_wait, IO::AIO::poll_cb
886	if IO::AIO::nreqs;
887		1428
888	=item IO::AIO::min_parallel $nthreads	1429	=item IO::AIO::min_parallel $nthreads
889		1430
890	Set the minimum number of AIO threads to C<$nthreads>. The current	1431	Set the minimum number of AIO threads to C<$nthreads>. The current
891	default is C<8>, which means eight asynchronous operations can execute	1432	default is C<8>, which means eight asynchronous operations can execute
892	concurrently at any one time (the number of outstanding requests,	1433	concurrently at any one time (the number of outstanding requests,
893	however, is unlimited).	1434	however, is unlimited).
894		1435
895	IO::AIO starts threads only on demand, when an AIO request is queued and	1436	IO::AIO starts threads only on demand, when an AIO request is queued and
896	no free thread exists.	1437	no free thread exists. Please note that queueing up a hundred requests can
		1438	create demand for a hundred threads, even if it turns out that everything
		1439	is in the cache and could have been processed faster by a single thread.
897		1440
898	It is recommended to keep the number of threads relatively low, as some	1441	It is recommended to keep the number of threads relatively low, as some
899	Linux kernel versions will scale negatively with the number of threads	1442	Linux kernel versions will scale negatively with the number of threads
900	(higher parallelity => MUCH higher latency). With current Linux 2.6	1443	(higher parallelity => MUCH higher latency). With current Linux 2.6
901	versions, 4-32 threads should be fine.	1444	versions, 4-32 threads should be fine.
…		…
915	This module automatically runs C<max_parallel 0> at program end, to ensure	1458	This module automatically runs C<max_parallel 0> at program end, to ensure
916	that all threads are killed and that there are no outstanding requests.	1459	that all threads are killed and that there are no outstanding requests.
917		1460
918	Under normal circumstances you don't need to call this function.	1461	Under normal circumstances you don't need to call this function.
919		1462
		1463	=item IO::AIO::max_idle $nthreads
		1464
		1465	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1466	threads that did not get a request to process within 10 seconds). That
		1467	means if a thread becomes idle while C<$nthreads> other threads are also
		1468	idle, it will free its resources and exit.
		1469
		1470	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1471	to allow for extremely high load situations, but want to free resources
		1472	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1473
		1474	The default is probably ok in most situations, especially if thread
		1475	creation is fast. If thread creation is very slow on your system you might
		1476	want to use larger values.
		1477
920	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1478	=item IO::AIO::max_outstanding $maxreqs
921		1479
922	This is a very bad function to use in interactive programs because it	1480	This is a very bad function to use in interactive programs because it
923	blocks, and a bad way to reduce concurrency because it is inexact: Better	1481	blocks, and a bad way to reduce concurrency because it is inexact: Better
924	use an C<aio_group> together with a feed callback.	1482	use an C<aio_group> together with a feed callback.
925		1483
926	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1484	Sets the maximum number of outstanding requests to C<$nreqs>. If you
927	to queue up more than this number of requests, the next call to the	1485	do queue up more than this number of requests, the next call to the
928	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1486	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
929	function will block until the limit is no longer exceeded.	1487	function will block until the limit is no longer exceeded.
930		1488
931	The default value is very large, so there is no practical limit on the	1489	The default value is very large, so there is no practical limit on the
932	number of outstanding requests.	1490	number of outstanding requests.
933		1491
934	You can still queue as many requests as you want. Therefore,	1492	You can still queue as many requests as you want. Therefore,
935	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1493	C<max_outstanding> is mainly useful in simple scripts (with low values) or
936	as a stop gap to shield against fatal memory overflow (with large values).	1494	as a stop gap to shield against fatal memory overflow (with large values).
937		1495
938	=back	1496	=back
939		1497
		1498	=head3 STATISTICAL INFORMATION
		1499
		1500	=over
		1501
		1502	=item IO::AIO::nreqs
		1503
		1504	Returns the number of requests currently in the ready, execute or pending
		1505	states (i.e. for which their callback has not been invoked yet).
		1506
		1507	Example: wait till there are no outstanding requests anymore:
		1508
		1509	IO::AIO::poll_wait, IO::AIO::poll_cb
		1510	while IO::AIO::nreqs;
		1511
		1512	=item IO::AIO::nready
		1513
		1514	Returns the number of requests currently in the ready state (not yet
		1515	executed).
		1516
		1517	=item IO::AIO::npending
		1518
		1519	Returns the number of requests currently in the pending state (executed,
		1520	but not yet processed by poll_cb).
		1521
		1522	=back
		1523
		1524	=head3 MISCELLANEOUS FUNCTIONS
		1525
		1526	IO::AIO implements some functions that might be useful, but are not
		1527	asynchronous.
		1528
		1529	=over 4
		1530
		1531	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1532
		1533	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1534	but is blocking (this makes most sense if you know the input data is
		1535	likely cached already and the output filehandle is set to non-blocking
		1536	operations).
		1537
		1538	Returns the number of bytes copied, or C<-1> on error.
		1539
		1540	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1541
		1542	Simply calls the C<posix_fadvise> function (see it's
		1543	manpage for details). The following advice constants are
		1544	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1545	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1546	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1547
		1548	On systems that do not implement C<posix_fadvise>, this function returns
		1549	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1550
		1551	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1552
		1553	Memory-maps a file (or anonymous memory range) and attaches it to the
		1554	given C<$scalar>, which will act like a string scalar.
		1555
		1556	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1557	change the string length, and most read-only operations such as copying it
		1558	or searching it with regexes and so on.
		1559
		1560	Anything else is unsafe and will, at best, result in memory leaks.
		1561
		1562	The memory map associated with the C<$scalar> is automatically removed
		1563	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1564	C<IO::AIO::munmap> functions are called.
		1565
		1566	This calls the C<mmap>(2) function internally. See your system's manual
		1567	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1568
		1569	The C<$length> must be larger than zero and smaller than the actual
		1570	filesize.
		1571
		1572	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1573	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1574
		1575	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1576	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1577	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1578	(which is set to C<MAP_ANON> if your system only provides this
		1579	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1580	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1581	C<IO::AIO::MAP_NONBLOCK>
		1582
		1583	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1584
		1585	Example:
		1586
		1587	use Digest::MD5;
		1588	use IO::AIO;
		1589
		1590	open my $fh, "<verybigfile"
		1591	or die "$!";
		1592
		1593	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1594	or die "verybigfile: $!";
		1595
		1596	my $fast_md5 = md5 $data;
		1597
		1598	=item IO::AIO::munmap $scalar
		1599
		1600	Removes a previous mmap and undefines the C<$scalar>.
		1601
		1602	=item IO::AIO::mlockall $flags
		1603
		1604	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1605	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL__FUTURE>).
		1606
		1607	On systems that do not implement C<mlockall>, this function returns
		1608	ENOSYS, otherwise the return value of C<mlockall>.
		1609
		1610	=item IO::AIO::munlockall
		1611
		1612	Calls the C<munlockall> function.
		1613
		1614	On systems that do not implement C<munlockall>, this function returns
		1615	ENOSYS, otherwise the return value of C<munlockall>.
		1616
		1617	=back
		1618
940	=cut	1619	=cut
941		1620
942	# support function to convert a fd into a perl filehandle
943	sub _fd2fh {
944	return undef if $_[0] < 0;
945
946	# try to generate nice filehandles
947	my $sym = "IO::AIO::fd#$_[0]";
948	local *$sym;
949
950	open *$sym, "+<&=$_[0]" # usually works under any unix
951	or open *$sym, "<&=$_[0]" # cygwin needs this
952	or open *$sym, ">&=$_[0]" # or this
953	or return undef;
954
955	*$sym
956	}
957
958	min_parallel 8;	1621	min_parallel 8;
959		1622
		1623	END { flush }
		1624
960	1;	1625	1;
		1626
		1627	=head1 EVENT LOOP INTEGRATION
		1628
		1629	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1630	automatically into many event loops:
		1631
		1632	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1633	use AnyEvent::AIO;
		1634
		1635	You can also integrate IO::AIO manually into many event loops, here are
		1636	some examples of how to do this:
		1637
		1638	# EV integration
		1639	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1640
		1641	# Event integration
		1642	Event->io (fd => IO::AIO::poll_fileno,
		1643	poll => 'r',
		1644	cb => \&IO::AIO::poll_cb);
		1645
		1646	# Glib/Gtk2 integration
		1647	add_watch Glib::IO IO::AIO::poll_fileno,
		1648	in => sub { IO::AIO::poll_cb; 1 };
		1649
		1650	# Tk integration
		1651	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1652	readable => \&IO::AIO::poll_cb);
		1653
		1654	# Danga::Socket integration
		1655	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1656	\&IO::AIO::poll_cb);
961		1657
962	=head2 FORK BEHAVIOUR	1658	=head2 FORK BEHAVIOUR
963		1659
964	This module should do "the right thing" when the process using it forks:	1660	This module should do "the right thing" when the process using it forks:
965		1661
…		…
983	bytes of memory. In addition, stat requests need a stat buffer (possibly	1679	bytes of memory. In addition, stat requests need a stat buffer (possibly
984	a few hundred bytes), readdir requires a result buffer and so on. Perl	1680	a few hundred bytes), readdir requires a result buffer and so on. Perl
985	scalars and other data passed into aio requests will also be locked and	1681	scalars and other data passed into aio requests will also be locked and
986	will consume memory till the request has entered the done state.	1682	will consume memory till the request has entered the done state.
987		1683
988	This is now awfully much, so queuing lots of requests is not usually a	1684	This is not awfully much, so queuing lots of requests is not usually a
989	problem.	1685	problem.
990		1686
991	Per-thread usage:	1687	Per-thread usage:
992		1688
993	In the execution phase, some aio requests require more memory for	1689	In the execution phase, some aio requests require more memory for
…		…
998		1694
999	Known bugs will be fixed in the next release.	1695	Known bugs will be fixed in the next release.
1000		1696
1001	=head1 SEE ALSO	1697	=head1 SEE ALSO
1002		1698
1003	L<Coro::AIO>.	1699	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1700	more natural syntax.
1004		1701
1005	=head1 AUTHOR	1702	=head1 AUTHOR
1006		1703
1007	Marc Lehmann <schmorp@schmorp.de>	1704	Marc Lehmann <schmorp@schmorp.de>
1008	http://home.schmorp.de/	1705	http://home.schmorp.de/

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