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Revision 1.96 by root, Fri Dec 22 04:05:50 2006 UTC vs.
Revision 1.186 by root, Thu Dec 30 07:19:31 2010 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51
52	=head1 DESCRIPTION	31	=head1 DESCRIPTION
53		32
54	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
55	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
56		36
57	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
58	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
59	will still block, but you can do something else in the meantime. This	39	will still block, but you can do something else in the meantime. This
60	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
62	etc.), but can also be used to easily do operations in parallel that are	42	etc.), but can also be used to easily do operations in parallel that are
63	normally done sequentially, e.g. stat'ing many files, which is much faster	43	normally done sequentially, e.g. stat'ing many files, which is much faster
64	on a RAID volume or over NFS when you do a number of stat operations	44	on a RAID volume or over NFS when you do a number of stat operations
65	concurrently.	45	concurrently.
66		46
67	While most of this works on all types of file descriptors (for example	47	While most of this works on all types of file descriptors (for
68	sockets), using these functions on file descriptors that support	48	example sockets), using these functions on file descriptors that
69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or	49	support nonblocking operation (again, sockets, pipes etc.) is
70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop	50	very inefficient. Use an event loop for that (such as the L<EV>
71	for that (such as the L<Event|Event> module): IO::AIO will naturally fit	51	module): IO::AIO will naturally fit into such an event loop itself.
72	into such an event loop itself.
73		52
74	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
75	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
76	in perl, and the threads created by this module will not be visible	55	in perl, and the threads created by this module will not be visible
77	to perl. In the future, this module might make use of the native aio	56	to perl. In the future, this module might make use of the native aio
…		…
79	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
80	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
81	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
82	using threads anyway.	61	using threads anyway.
83		62
84	Although the module will work with in the presence of other (Perl-)	63	Although the module will work in the presence of other (Perl-) threads,
85	threads, it is currently not reentrant in any way, so use appropriate	64	it is currently not reentrant in any way, so use appropriate locking
86	locking yourself, always call C<poll_cb> from within the same thread, or	65	yourself, always call C<poll_cb> from within the same thread, or never
87	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
88		67
89	=head2 EXAMPLE	68	=head2 EXAMPLE
90		69
91	This is a simple example that uses the Event module and loads	70	This is a simple example that uses the EV module and loads
92	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
93		72
94	use Fcntl;	73	use Fcntl;
95	use Event;	74	use EV;
96	use IO::AIO;	75	use IO::AIO;
97		76
98	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
99	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
100	poll => 'r',
101	cb => \&IO::AIO::poll_cb);
102		79
103	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105	my $fh = shift	82	my $fh = shift
106	or die "error while opening: $!";	83	or die "error while opening: $!";
107		84
108	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
109	my $size = -s $fh;	86	my $size = -s $fh;
…		…
118		95
119	# file contents now in $contents	96	# file contents now in $contents
120	print $contents;	97	print $contents;
121		98
122	# exit event loop and program	99	# exit event loop and program
123	Event::unloop;	100	EV::unloop;
124	};	101	};
125	};	102	};
126		103
127	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
128	# check for sockets etc. etc.	105	# check for sockets etc. etc.
129		106
130	# process events as long as there are some:	107	# process events as long as there are some:
131	Event::loop;	108	EV::loop;
132		109
133	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
134		111
135	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
136	directly visible to Perl.	113	directly visible to Perl.
…		…
184		161
185	=cut	162	=cut
186		163
187	package IO::AIO;	164	package IO::AIO;
188		165
189	no warnings;	166	use Carp ();
190	use strict 'vars';	167
		168	use common::sense;
191		169
192	use base 'Exporter';	170	use base 'Exporter';
193		171
194	BEGIN {	172	BEGIN {
195	our $VERSION = '2.21';	173	our $VERSION = '3.71';
196		174
197	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
198	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
199	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
200	aio_move aio_copy aio_group aio_nop aio_mknod);	178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		179	aio_rename aio_link aio_move aio_copy aio_group
		180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs);
		184
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle
204	nreqs nready npending nthreads	188	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	189	max_poll_time max_poll_reqs
		190	sendfile fadvise madvise
		191	mmap munmap munlock munlockall);
		192
		193	push @AIO_REQ, qw(aio_busy); # not exported
206		194
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		196
209	require XSLoader;	197	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
211	}	199	}
212		200
213	=head1 FUNCTIONS	201	=head1 FUNCTIONS
		202
		203	=head2 QUICK OVERVIEW
		204
		205	This section simply lists the prototypes of the most important functions
		206	for quick reference. See the following sections for function-by-function
		207	documentation.
		208
		209	aio_open $pathname, $flags, $mode, $callback->($fh)
		210	aio_close $fh, $callback->($status)
		211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		214	aio_readahead $fh,$offset,$length, $callback->($retval)
		215	aio_stat $fh_or_path, $callback->($status)
		216	aio_lstat $fh, $callback->($status)
		217	aio_statvfs $fh_or_path, $callback->($statvfs)
		218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		220	aio_truncate $fh_or_path, $offset, $callback->($status)
		221	aio_chmod $fh_or_path, $mode, $callback->($status)
		222	aio_unlink $pathname, $callback->($status)
		223	aio_mknod $path, $mode, $dev, $callback->($status)
		224	aio_link $srcpath, $dstpath, $callback->($status)
		225	aio_symlink $srcpath, $dstpath, $callback->($status)
		226	aio_readlink $path, $callback->($link)
		227	aio_rename $srcpath, $dstpath, $callback->($status)
		228	aio_mkdir $pathname, $mode, $callback->($status)
		229	aio_rmdir $pathname, $callback->($status)
		230	aio_readdir $pathname, $callback->($entries)
		231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		234	aio_load $path, $data, $callback->($status)
		235	aio_copy $srcpath, $dstpath, $callback->($status)
		236	aio_move $srcpath, $dstpath, $callback->($status)
		237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		238	aio_rmtree $path, $callback->($status)
		239	aio_sync $callback->($status)
		240	aio_fsync $fh, $callback->($status)
		241	aio_fdatasync $fh, $callback->($status)
		242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		243	aio_pathsync $path, $callback->($status)
		244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		247	aio_mlockall $flags, $callback->($status)
		248	aio_group $callback->(...)
		249	aio_nop $callback->()
		250
		251	$prev_pri = aioreq_pri [$pri]
		252	aioreq_nice $pri_adjust
		253
		254	IO::AIO::poll_wait
		255	IO::AIO::poll_cb
		256	IO::AIO::poll
		257	IO::AIO::flush
		258	IO::AIO::max_poll_reqs $nreqs
		259	IO::AIO::max_poll_time $seconds
		260	IO::AIO::min_parallel $nthreads
		261	IO::AIO::max_parallel $nthreads
		262	IO::AIO::max_idle $nthreads
		263	IO::AIO::max_outstanding $maxreqs
		264	IO::AIO::nreqs
		265	IO::AIO::nready
		266	IO::AIO::npending
		267
		268	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		269	IO::AIO::fadvise $fh, $offset, $len, $advice
		270	IO::AIO::madvise $scalar, $offset, $length, $advice
		271	IO::AIO::mprotect $scalar, $offset, $length, $protect
		272	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		273	IO::AIO::munlockall
214		274
215	=head2 AIO REQUEST FUNCTIONS	275	=head2 AIO REQUEST FUNCTIONS
216		276
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	277	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	278	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	279	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	280	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	281	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	282	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	283	syscall has been executed asynchronously.
224		284
225	All functions expecting a filehandle keep a copy of the filehandle	285	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	286	internally until the request has finished.
227		287
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	301	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)	302	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	303	use something else to ensure your scalar has the correct contents.
244		304
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	305	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	306	handles correctly whether it is set or not.
247		307
248	=over 4	308	=over 4
249		309
250	=item $prev_pri = aioreq_pri [$pri]	310	=item $prev_pri = aioreq_pri [$pri]
251		311
…		…
271	aio_read $_[0], ..., sub {	331	aio_read $_[0], ..., sub {
272	...	332	...
273	};	333	};
274	};	334	};
275		335
		336
276	=item aioreq_nice $pri_adjust	337	=item aioreq_nice $pri_adjust
277		338
278	Similar to C<aioreq_pri>, but subtracts the given value from the current	339	Similar to C<aioreq_pri>, but subtracts the given value from the current
279	priority, so the effect is cumulative.	340	priority, so the effect is cumulative.
		341
280		342
281	=item aio_open $pathname, $flags, $mode, $callback->($fh)	343	=item aio_open $pathname, $flags, $mode, $callback->($fh)
282		344
283	Asynchronously open or create a file and call the callback with a newly	345	Asynchronously open or create a file and call the callback with a newly
284	created filehandle for the file.	346	created filehandle for the file.
…		…
290	list. They are the same as used by C<sysopen>.	352	list. They are the same as used by C<sysopen>.
291		353
292	Likewise, C<$mode> specifies the mode of the newly created file, if it	354	Likewise, C<$mode> specifies the mode of the newly created file, if it
293	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	355	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
294	except that it is mandatory (i.e. use C<0> if you don't create new files,	356	except that it is mandatory (i.e. use C<0> if you don't create new files,
295	and C<0666> or C<0777> if you do).	357	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		358	by the umask in effect then the request is being executed, so better never
		359	change the umask.
296		360
297	Example:	361	Example:
298		362
299	aio_open "/etc/passwd", O_RDONLY, 0, sub {	363	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
300	if ($_[0]) {	364	if ($_[0]) {
301	print "open successful, fh is $_[0]\n";	365	print "open successful, fh is $_[0]\n";
302	...	366	...
303	} else {	367	} else {
304	die "open failed: $!\n";	368	die "open failed: $!\n";
305	}	369	}
306	};	370	};
307		371
		372
308	=item aio_close $fh, $callback->($status)	373	=item aio_close $fh, $callback->($status)
309		374
310	Asynchronously close a file and call the callback with the result	375	Asynchronously close a file and call the callback with the result
311	code. I<WARNING:> although accepted, you should not pass in a perl	376	code.
312	filehandle here, as perl will likely close the file descriptor another
313	time when the filehandle is destroyed. Normally, you can safely call perls
314	C<close> or just let filehandles go out of scope.
315		377
316	This is supposed to be a bug in the API, so that might change. It's	378	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
317	therefore best to avoid this function.	379	closing the file descriptor associated with the filehandle itself.
		380
		381	Therefore, C<aio_close> will not close the filehandle - instead it will
		382	use dup2 to overwrite the file descriptor with the write-end of a pipe
		383	(the pipe fd will be created on demand and will be cached).
		384
		385	Or in other words: the file descriptor will be closed, but it will not be
		386	free for reuse until the perl filehandle is closed.
		387
		388	=cut
318		389
319	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	390	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320		391
321	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	392	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322		393
323	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	394	Reads or writes C<$length> bytes from or to the specified C<$fh> and
324	into the scalar given by C<data> and offset C<dataoffset> and calls the	395	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
325	callback without the actual number of bytes read (or -1 on error, just	396	and calls the callback without the actual number of bytes read (or -1 on
326	like the syscall).	397	error, just like the syscall).
		398
		399	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		400	offset plus the actual number of bytes read.
		401
		402	If C<$offset> is undefined, then the current file descriptor offset will
		403	be used (and updated), otherwise the file descriptor offset will not be
		404	changed by these calls.
		405
		406	If C<$length> is undefined in C<aio_write>, use the remaining length of
		407	C<$data>.
		408
		409	If C<$dataoffset> is less than zero, it will be counted from the end of
		410	C<$data>.
327		411
328	The C<$data> scalar I<MUST NOT> be modified in any way while the request	412	The C<$data> scalar I<MUST NOT> be modified in any way while the request
329	is outstanding. Modifying it can result in segfaults or WW3 (if the	413	is outstanding. Modifying it can result in segfaults or World War III (if
330	necessary/optional hardware is installed).	414	the necessary/optional hardware is installed).
331		415
332	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	416	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
333	offset C<0> within the scalar:	417	offset C<0> within the scalar:
334		418
335	aio_read $fh, 7, 15, $buffer, 0, sub {	419	aio_read $fh, 7, 15, $buffer, 0, sub {
336	$_[0] > 0 or die "read error: $!";	420	$_[0] > 0 or die "read error: $!";
337	print "read $_[0] bytes: <$buffer>\n";	421	print "read $_[0] bytes: <$buffer>\n";
338	};	422	};
		423
339		424
340	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	425	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
341		426
342	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	427	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
343	reading at byte offset C<$in_offset>, and starts writing at the current	428	reading at byte offset C<$in_offset>, and starts writing at the current
344	file offset of C<$out_fh>. Because of that, it is not safe to issue more	429	file offset of C<$out_fh>. Because of that, it is not safe to issue more
345	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	430	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
346	other.	431	other.
347		432
		433	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		434	are written, and there is no way to find out how many bytes have been read
		435	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
		436	bytes written to C<$out_fh>. Only if the result value equals C<$length>
		437	one can assume that C<$length> bytes have been read.
		438
		439	Unlike with other C<aio_> functions, it makes a lot of sense to use
		440	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		441	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		442	the socket I/O will be non-blocking. Note, however, that you can run into
		443	a trap where C<aio_sendfile> reads some data with readahead, then fails
		444	to write all data, and when the socket is ready the next time, the data
		445	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		446	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		447	much better.
		448
348	This call tries to make use of a native C<sendfile> syscall to provide	449	This call tries to make use of a native C<sendfile> syscall to provide
349	zero-copy operation. For this to work, C<$out_fh> should refer to a	450	zero-copy operation. For this to work, C<$out_fh> should refer to a
350	socket, and C<$in_fh> should refer to mmap'able file.	451	socket, and C<$in_fh> should refer to an mmap'able file.
351		452
352	If the native sendfile call fails or is not implemented, it will be	453	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		454	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
353	emulated, so you can call C<aio_sendfile> on any type of filehandle	455	it will be emulated, so you can call C<aio_sendfile> on any type of
354	regardless of the limitations of the operating system.	456	filehandle regardless of the limitations of the operating system.
355		457
356	Please note, however, that C<aio_sendfile> can read more bytes from
357	C<$in_fh> than are written, and there is no way to find out how many
358	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
359	provides the number of bytes written to C<$out_fh>. Only if the result
360	value equals C<$length> one can assume that C<$length> bytes have been
361	read.
362		458
363	=item aio_readahead $fh,$offset,$length, $callback->($retval)	459	=item aio_readahead $fh,$offset,$length, $callback->($retval)
364		460
365	C<aio_readahead> populates the page cache with data from a file so that	461	C<aio_readahead> populates the page cache with data from a file so that
366	subsequent reads from that file will not block on disk I/O. The C<$offset>	462	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
372	file. The current file offset of the file is left unchanged.	468	file. The current file offset of the file is left unchanged.
373		469
374	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	470	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
375	emulated by simply reading the data, which would have a similar effect.	471	emulated by simply reading the data, which would have a similar effect.
376		472
		473
377	=item aio_stat $fh_or_path, $callback->($status)	474	=item aio_stat $fh_or_path, $callback->($status)
378		475
379	=item aio_lstat $fh, $callback->($status)	476	=item aio_lstat $fh, $callback->($status)
380		477
381	Works like perl's C<stat> or C<lstat> in void context. The callback will	478	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
394	aio_stat "/etc/passwd", sub {	491	aio_stat "/etc/passwd", sub {
395	$_[0] and die "stat failed: $!";	492	$_[0] and die "stat failed: $!";
396	print "size is ", -s _, "\n";	493	print "size is ", -s _, "\n";
397	};	494	};
398		495
		496
		497	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		498
		499	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		500	whether a file handle or path was passed.
		501
		502	On success, the callback is passed a hash reference with the following
		503	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		504	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		505	is passed.
		506
		507	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		508	C<ST_NOSUID>.
		509
		510	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		511	their correct value when available, or to C<0> on systems that do
		512	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		513	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		514	C<ST_NODIRATIME> and C<ST_RELATIME>.
		515
		516	Example: stat C</wd> and dump out the data if successful.
		517
		518	aio_statvfs "/wd", sub {
		519	my $f = $_[0]
		520	or die "statvfs: $!";
		521
		522	use Data::Dumper;
		523	say Dumper $f;
		524	};
		525
		526	# result:
		527	{
		528	bsize => 1024,
		529	bfree => 4333064312,
		530	blocks => 10253828096,
		531	files => 2050765568,
		532	flag => 4096,
		533	favail => 2042092649,
		534	bavail => 4333064312,
		535	ffree => 2042092649,
		536	namemax => 255,
		537	frsize => 1024,
		538	fsid => 1810
		539	}
		540
		541
		542	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		543
		544	Works like perl's C<utime> function (including the special case of $atime
		545	and $mtime being undef). Fractional times are supported if the underlying
		546	syscalls support them.
		547
		548	When called with a pathname, uses utimes(2) if available, otherwise
		549	utime(2). If called on a file descriptor, uses futimes(2) if available,
		550	otherwise returns ENOSYS, so this is not portable.
		551
		552	Examples:
		553
		554	# set atime and mtime to current time (basically touch(1)):
		555	aio_utime "path", undef, undef;
		556	# set atime to current time and mtime to beginning of the epoch:
		557	aio_utime "path", time, undef; # undef==0
		558
		559
		560	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		561
		562	Works like perl's C<chown> function, except that C<undef> for either $uid
		563	or $gid is being interpreted as "do not change" (but -1 can also be used).
		564
		565	Examples:
		566
		567	# same as "chown root path" in the shell:
		568	aio_chown "path", 0, -1;
		569	# same as above:
		570	aio_chown "path", 0, undef;
		571
		572
		573	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		574
		575	Works like truncate(2) or ftruncate(2).
		576
		577
		578	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		579
		580	Works like perl's C<chmod> function.
		581
		582
399	=item aio_unlink $pathname, $callback->($status)	583	=item aio_unlink $pathname, $callback->($status)
400		584
401	Asynchronously unlink (delete) a file and call the callback with the	585	Asynchronously unlink (delete) a file and call the callback with the
402	result code.	586	result code.
403		587
		588
404	=item aio_mknod $path, $mode, $dev, $callback->($status)	589	=item aio_mknod $path, $mode, $dev, $callback->($status)
405		590
406	[EXPERIMENTAL]	591	[EXPERIMENTAL]
407		592
408	Asynchronously create a device node (or fifo). See mknod(2).	593	Asynchronously create a device node (or fifo). See mknod(2).
409		594
410	The only (POSIX-) portable way of calling this function is:	595	The only (POSIX-) portable way of calling this function is:
411		596
412	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	597	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		598
413		599
414	=item aio_link $srcpath, $dstpath, $callback->($status)	600	=item aio_link $srcpath, $dstpath, $callback->($status)
415		601
416	Asynchronously create a new link to the existing object at C<$srcpath> at	602	Asynchronously create a new link to the existing object at C<$srcpath> at
417	the path C<$dstpath> and call the callback with the result code.	603	the path C<$dstpath> and call the callback with the result code.
418		604
		605
419	=item aio_symlink $srcpath, $dstpath, $callback->($status)	606	=item aio_symlink $srcpath, $dstpath, $callback->($status)
420		607
421	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	608	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
422	the path C<$dstpath> and call the callback with the result code.	609	the path C<$dstpath> and call the callback with the result code.
		610
423		611
424	=item aio_readlink $path, $callback->($link)	612	=item aio_readlink $path, $callback->($link)
425		613
426	Asynchronously read the symlink specified by C<$path> and pass it to	614	Asynchronously read the symlink specified by C<$path> and pass it to
427	the callback. If an error occurs, nothing or undef gets passed to the	615	the callback. If an error occurs, nothing or undef gets passed to the
428	callback.	616	callback.
429		617
		618
430	=item aio_rename $srcpath, $dstpath, $callback->($status)	619	=item aio_rename $srcpath, $dstpath, $callback->($status)
431		620
432	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	621	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
433	rename(2) and call the callback with the result code.	622	rename(2) and call the callback with the result code.
434		623
		624
		625	=item aio_mkdir $pathname, $mode, $callback->($status)
		626
		627	Asynchronously mkdir (create) a directory and call the callback with
		628	the result code. C<$mode> will be modified by the umask at the time the
		629	request is executed, so do not change your umask.
		630
		631
435	=item aio_rmdir $pathname, $callback->($status)	632	=item aio_rmdir $pathname, $callback->($status)
436		633
437	Asynchronously rmdir (delete) a directory and call the callback with the	634	Asynchronously rmdir (delete) a directory and call the callback with the
438	result code.	635	result code.
		636
439		637
440	=item aio_readdir $pathname, $callback->($entries)	638	=item aio_readdir $pathname, $callback->($entries)
441		639
442	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	640	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
443	directory (i.e. opendir + readdir + closedir). The entries will not be	641	directory (i.e. opendir + readdir + closedir). The entries will not be
444	sorted, and will B<NOT> include the C<.> and C<..> entries.	642	sorted, and will B<NOT> include the C<.> and C<..> entries.
445		643
446	The callback a single argument which is either C<undef> or an array-ref	644	The callback is passed a single argument which is either C<undef> or an
447	with the filenames.	645	array-ref with the filenames.
		646
		647
		648	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		649
		650	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		651	behaviour and output format. In case of an error, C<$entries> will be
		652	C<undef>.
		653
		654	The flags are a combination of the following constants, ORed together (the
		655	flags will also be passed to the callback, possibly modified):
		656
		657	=over 4
		658
		659	=item IO::AIO::READDIR_DENTS
		660
		661	When this flag is off, then the callback gets an arrayref with of names
		662	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		663	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		664	entry in more detail.
		665
		666	C<$name> is the name of the entry.
		667
		668	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		669
		670	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		671	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		672	C<IO::AIO::DT_WHT>.
		673
		674	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		675	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		676	scalars are read-only: you can not modify them.
		677
		678	C<$inode> is the inode number (which might not be exact on systems with 64
		679	bit inode numbers and 32 bit perls). This field has unspecified content on
		680	systems that do not deliver the inode information.
		681
		682	=item IO::AIO::READDIR_DIRS_FIRST
		683
		684	When this flag is set, then the names will be returned in an order where
		685	likely directories come first. This is useful when you need to quickly
		686	find directories, or you want to find all directories while avoiding to
		687	stat() each entry.
		688
		689	If the system returns type information in readdir, then this is used
		690	to find directories directly. Otherwise, likely directories are files
		691	beginning with ".", or otherwise files with no dots, of which files with
		692	short names are tried first.
		693
		694	=item IO::AIO::READDIR_STAT_ORDER
		695
		696	When this flag is set, then the names will be returned in an order
		697	suitable for stat()'ing each one. That is, when you plan to stat()
		698	all files in the given directory, then the returned order will likely
		699	be fastest.
		700
		701	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		702	the likely dirs come first, resulting in a less optimal stat order.
		703
		704	=item IO::AIO::READDIR_FOUND_UNKNOWN
		705
		706	This flag should not be set when calling C<aio_readdirx>. Instead, it
		707	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		708	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		709	C<$type>'s are known, which can be used to speed up some algorithms.
		710
		711	=back
		712
		713
		714	=item aio_load $path, $data, $callback->($status)
		715
		716	This is a composite request that tries to fully load the given file into
		717	memory. Status is the same as with aio_read.
		718
		719	=cut
		720
		721	sub aio_load($$;$) {
		722	my ($path, undef, $cb) = @_;
		723	my $data = \$_[1];
		724
		725	my $pri = aioreq_pri;
		726	my $grp = aio_group $cb;
		727
		728	aioreq_pri $pri;
		729	add $grp aio_open $path, O_RDONLY, 0, sub {
		730	my $fh = shift
		731	or return $grp->result (-1);
		732
		733	aioreq_pri $pri;
		734	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		735	$grp->result ($_[0]);
		736	};
		737	};
		738
		739	$grp
		740	}
448		741
449	=item aio_copy $srcpath, $dstpath, $callback->($status)	742	=item aio_copy $srcpath, $dstpath, $callback->($status)
450		743
451	Try to copy the I<file> (directories not supported as either source or	744	Try to copy the I<file> (directories not supported as either source or
452	destination) from C<$srcpath> to C<$dstpath> and call the callback with	745	destination) from C<$srcpath> to C<$dstpath> and call the callback with
453	the C<0> (error) or C<-1> ok.	746	a status of C<0> (ok) or C<-1> (error, see C<$!>).
454		747
455	This is a composite request that it creates the destination file with	748	This is a composite request that creates the destination file with
456	mode 0200 and copies the contents of the source file into it using	749	mode 0200 and copies the contents of the source file into it using
457	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	750	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
458	uid/gid, in that order.	751	uid/gid, in that order.
459		752
460	If an error occurs, the partial destination file will be unlinked, if	753	If an error occurs, the partial destination file will be unlinked, if
…		…
462	errors are being ignored.	755	errors are being ignored.
463		756
464	=cut	757	=cut
465		758
466	sub aio_copy($$;$) {	759	sub aio_copy($$;$) {
467	aio_block {
468	my ($src, $dst, $cb) = @_;	760	my ($src, $dst, $cb) = @_;
469		761
470	my $pri = aioreq_pri;	762	my $pri = aioreq_pri;
471	my $grp = aio_group $cb;	763	my $grp = aio_group $cb;
472		764
473	aioreq_pri $pri;	765	aioreq_pri $pri;
474	add $grp aio_open $src, O_RDONLY, 0, sub {	766	add $grp aio_open $src, O_RDONLY, 0, sub {
475	if (my $src_fh = $_[0]) {	767	if (my $src_fh = $_[0]) {
476	my @stat = stat $src_fh;	768	my @stat = stat $src_fh; # hmm, might block over nfs?
477		769
478	aioreq_pri $pri;	770	aioreq_pri $pri;
479	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	771	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
480	if (my $dst_fh = $_[0]) {	772	if (my $dst_fh = $_[0]) {
481	aioreq_pri $pri;	773	aioreq_pri $pri;
482	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	774	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
483	if ($_[0] == $stat[7]) {	775	if ($_[0] == $stat[7]) {
484	$grp->result (0);	776	$grp->result (0);
485	close $src_fh;	777	close $src_fh;
486		778
487	# those should not normally block. should. should.
488	utime $stat[8], $stat[9], $dst;
489	chmod $stat[2] & 07777, $dst_fh;
490	chown $stat[4], $stat[5], $dst_fh;
491	close $dst_fh;
492	} else {	779	my $ch = sub {
493	$grp->result (-1);
494	close $src_fh;
495	close $dst_fh;
496
497	aioreq $pri;	780	aioreq_pri $pri;
		781	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		782	aioreq_pri $pri;
		783	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		784	aioreq_pri $pri;
498	add $grp aio_unlink $dst;	785	add $grp aio_close $dst_fh;
		786	}
		787	};
499	}	788	};
		789
		790	aioreq_pri $pri;
		791	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		792	if ($_[0] < 0 && $! == ENOSYS) {
		793	aioreq_pri $pri;
		794	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		795	} else {
		796	$ch->();
		797	}
		798	};
		799	} else {
		800	$grp->result (-1);
		801	close $src_fh;
		802	close $dst_fh;
		803
		804	aioreq $pri;
		805	add $grp aio_unlink $dst;
500	};	806	}
501	} else {
502	$grp->result (-1);
503	}	807	};
		808	} else {
		809	$grp->result (-1);
504	},	810	}
505
506	} else {
507	$grp->result (-1);
508	}	811	},
		812
		813	} else {
		814	$grp->result (-1);
509	};	815	}
510
511	$grp
512	}	816	};
		817
		818	$grp
513	}	819	}
514		820
515	=item aio_move $srcpath, $dstpath, $callback->($status)	821	=item aio_move $srcpath, $dstpath, $callback->($status)
516		822
517	Try to move the I<file> (directories not supported as either source or	823	Try to move the I<file> (directories not supported as either source or
518	destination) from C<$srcpath> to C<$dstpath> and call the callback with	824	destination) from C<$srcpath> to C<$dstpath> and call the callback with
519	the C<0> (error) or C<-1> ok.	825	a status of C<0> (ok) or C<-1> (error, see C<$!>).
520		826
521	This is a composite request that tries to rename(2) the file first. If	827	This is a composite request that tries to rename(2) the file first; if
522	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	828	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
523	that is successful, unlinking the C<$srcpath>.	829	that is successful, unlinks the C<$srcpath>.
524		830
525	=cut	831	=cut
526		832
527	sub aio_move($$;$) {	833	sub aio_move($$;$) {
528	aio_block {
529	my ($src, $dst, $cb) = @_;	834	my ($src, $dst, $cb) = @_;
530		835
531	my $pri = aioreq_pri;	836	my $pri = aioreq_pri;
532	my $grp = aio_group $cb;	837	my $grp = aio_group $cb;
533		838
534	aioreq_pri $pri;	839	aioreq_pri $pri;
535	add $grp aio_rename $src, $dst, sub {	840	add $grp aio_rename $src, $dst, sub {
536	if ($_[0] && $! == EXDEV) {	841	if ($_[0] && $! == EXDEV) {
537	aioreq_pri $pri;	842	aioreq_pri $pri;
538	add $grp aio_copy $src, $dst, sub {	843	add $grp aio_copy $src, $dst, sub {
539	$grp->result ($_[0]);
540
541	if (!$_[0]) {
542	aioreq_pri $pri;
543	add $grp aio_unlink $src;
544	}
545	};
546	} else {
547	$grp->result ($_[0]);	844	$grp->result ($_[0]);
		845
		846	if (!$_[0]) {
		847	aioreq_pri $pri;
		848	add $grp aio_unlink $src;
		849	}
548	}	850	};
		851	} else {
		852	$grp->result ($_[0]);
549	};	853	}
550
551	$grp
552	}	854	};
		855
		856	$grp
553	}	857	}
554		858
555	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	859	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
556		860
557	Scans a directory (similar to C<aio_readdir>) but additionally tries to	861	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
577		881
578	Implementation notes.	882	Implementation notes.
579		883
580	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	884	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
581		885
		886	If readdir returns file type information, then this is used directly to
		887	find directories.
		888
582	After reading the directory, the modification time, size etc. of the	889	Otherwise, after reading the directory, the modification time, size etc.
583	directory before and after the readdir is checked, and if they match (and	890	of the directory before and after the readdir is checked, and if they
584	isn't the current time), the link count will be used to decide how many	891	match (and isn't the current time), the link count will be used to decide
585	entries are directories (if >= 2). Otherwise, no knowledge of the number	892	how many entries are directories (if >= 2). Otherwise, no knowledge of the
586	of subdirectories will be assumed.	893	number of subdirectories will be assumed.
587		894
588	Then entries will be sorted into likely directories (everything without	895	Then entries will be sorted into likely directories a non-initial dot
589	a non-initial dot currently) and likely non-directories (everything	896	currently) and likely non-directories (see C<aio_readdirx>). Then every
590	else). Then every entry plus an appended C</.> will be C<stat>'ed,	897	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
591	likely directories first. If that succeeds, it assumes that the entry	898	in order of their inode numbers. If that succeeds, it assumes that the
592	is a directory or a symlink to directory (which will be checked	899	entry is a directory or a symlink to directory (which will be checked
593	seperately). This is often faster than stat'ing the entry itself because	900	seperately). This is often faster than stat'ing the entry itself because
594	filesystems might detect the type of the entry without reading the inode	901	filesystems might detect the type of the entry without reading the inode
595	data (e.g. ext2fs filetype feature).	902	data (e.g. ext2fs filetype feature), even on systems that cannot return
		903	the filetype information on readdir.
596		904
597	If the known number of directories (link count - 2) has been reached, the	905	If the known number of directories (link count - 2) has been reached, the
598	rest of the entries is assumed to be non-directories.	906	rest of the entries is assumed to be non-directories.
599		907
600	This only works with certainty on POSIX (= UNIX) filesystems, which	908	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
604	as those tend to return 0 or 1 as link counts, which disables the	912	as those tend to return 0 or 1 as link counts, which disables the
605	directory counting heuristic.	913	directory counting heuristic.
606		914
607	=cut	915	=cut
608		916
609	sub aio_scandir($$$) {	917	sub aio_scandir($$;$) {
610	aio_block {
611	my ($path, $maxreq, $cb) = @_;	918	my ($path, $maxreq, $cb) = @_;
612		919
613	my $pri = aioreq_pri;	920	my $pri = aioreq_pri;
614		921
615	my $grp = aio_group $cb;	922	my $grp = aio_group $cb;
616		923
617	$maxreq = 4 if $maxreq <= 0;	924	$maxreq = 4 if $maxreq <= 0;
618		925
619	# stat once	926	# stat once
		927	aioreq_pri $pri;
		928	add $grp aio_stat $path, sub {
		929	return $grp->result () if $_[0];
		930	my $now = time;
		931	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		932
		933	# read the directory entries
620	aioreq_pri $pri;	934	aioreq_pri $pri;
621	add $grp aio_stat $path, sub {	935	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		936	my $entries = shift
622	return $grp->result () if $_[0];	937	or return $grp->result ();
623	my $now = time;
624	my $hash1 = join ":", (stat _)[0,1,3,7,9];
625		938
626	# read the directory entries	939	# stat the dir another time
627	aioreq_pri $pri;	940	aioreq_pri $pri;
628	add $grp aio_readdir $path, sub {
629	my $entries = shift
630	or return $grp->result ();
631
632	# stat the dir another time
633	aioreq_pri $pri;
634	add $grp aio_stat $path, sub {	941	add $grp aio_stat $path, sub {
635	my $hash2 = join ":", (stat _)[0,1,3,7,9];	942	my $hash2 = join ":", (stat _)[0,1,3,7,9];
636		943
637	my $ndirs;	944	my $ndirs;
638		945
639	# take the slow route if anything looks fishy	946	# take the slow route if anything looks fishy
640	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	947	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
641	$ndirs = -1;	948	$ndirs = -1;
642	} else {	949	} else {
643	# if nlink == 2, we are finished	950	# if nlink == 2, we are finished
644	# on non-posix-fs's, we rely on nlink < 2	951	# for non-posix-fs's, we rely on nlink < 2
645	$ndirs = (stat _)[3] - 2	952	$ndirs = (stat _)[3] - 2
646	or return $grp->result ([], $entries);	953	or return $grp->result ([], $entries);
647	}	954	}
648		955
649	# sort into likely dirs and likely nondirs
650	# dirs == files without ".", short entries first
651	$entries = [map $_->[0],
652	sort { $b->[1] cmp $a->[1] }
653	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
654	@$entries];
655
656	my (@dirs, @nondirs);	956	my (@dirs, @nondirs);
657		957
658	my $statgrp = add $grp aio_group sub {	958	my $statgrp = add $grp aio_group sub {
659	$grp->result (\@dirs, \@nondirs);	959	$grp->result (\@dirs, \@nondirs);
660	};	960	};
661		961
662	limit $statgrp $maxreq;	962	limit $statgrp $maxreq;
663	feed $statgrp sub {	963	feed $statgrp sub {
664	return unless @$entries;	964	return unless @$entries;
665	my $entry = pop @$entries;	965	my $entry = shift @$entries;
666		966
667	aioreq_pri $pri;	967	aioreq_pri $pri;
668	add $statgrp aio_stat "$path/$entry/.", sub {	968	add $statgrp aio_stat "$path/$entry/.", sub {
669	if ($_[0] < 0) {	969	if ($_[0] < 0) {
670	push @nondirs, $entry;	970	push @nondirs, $entry;
671	} else {	971	} else {
672	# need to check for real directory	972	# need to check for real directory
673	aioreq_pri $pri;	973	aioreq_pri $pri;
674	add $statgrp aio_lstat "$path/$entry", sub {	974	add $statgrp aio_lstat "$path/$entry", sub {
675	if (-d _) {	975	if (-d _) {
676	push @dirs, $entry;	976	push @dirs, $entry;
677		977
678	unless (--$ndirs) {	978	unless (--$ndirs) {
679	push @nondirs, @$entries;	979	push @nondirs, @$entries;
680	feed $statgrp;	980	feed $statgrp;
681	}
682	} else {
683	push @nondirs, $entry;
684	}	981	}
		982	} else {
		983	push @nondirs, $entry;
685	}	984	}
686	}	985	}
687	};	986	}
688	};	987	};
689	};	988	};
690	};	989	};
691	};	990	};
692
693	$grp
694	}	991	};
		992
		993	$grp
695	}	994	}
		995
		996	=item aio_rmtree $path, $callback->($status)
		997
		998	Delete a directory tree starting (and including) C<$path>, return the
		999	status of the final C<rmdir> only. This is a composite request that
		1000	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		1001	everything else.
		1002
		1003	=cut
		1004
		1005	sub aio_rmtree;
		1006	sub aio_rmtree($;$) {
		1007	my ($path, $cb) = @_;
		1008
		1009	my $pri = aioreq_pri;
		1010	my $grp = aio_group $cb;
		1011
		1012	aioreq_pri $pri;
		1013	add $grp aio_scandir $path, 0, sub {
		1014	my ($dirs, $nondirs) = @_;
		1015
		1016	my $dirgrp = aio_group sub {
		1017	add $grp aio_rmdir $path, sub {
		1018	$grp->result ($_[0]);
		1019	};
		1020	};
		1021
		1022	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1023	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1024
		1025	add $grp $dirgrp;
		1026	};
		1027
		1028	$grp
		1029	}
		1030
		1031	=item aio_sync $callback->($status)
		1032
		1033	Asynchronously call sync and call the callback when finished.
696		1034
697	=item aio_fsync $fh, $callback->($status)	1035	=item aio_fsync $fh, $callback->($status)
698		1036
699	Asynchronously call fsync on the given filehandle and call the callback	1037	Asynchronously call fsync on the given filehandle and call the callback
700	with the fsync result code.	1038	with the fsync result code.
…		…
704	Asynchronously call fdatasync on the given filehandle and call the	1042	Asynchronously call fdatasync on the given filehandle and call the
705	callback with the fdatasync result code.	1043	callback with the fdatasync result code.
706		1044
707	If this call isn't available because your OS lacks it or it couldn't be	1045	If this call isn't available because your OS lacks it or it couldn't be
708	detected, it will be emulated by calling C<fsync> instead.	1046	detected, it will be emulated by calling C<fsync> instead.
		1047
		1048	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1049
		1050	Sync the data portion of the file specified by C<$offset> and C<$length>
		1051	to disk (but NOT the metadata), by calling the Linux-specific
		1052	sync_file_range call. If sync_file_range is not available or it returns
		1053	ENOSYS, then fdatasync or fsync is being substituted.
		1054
		1055	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1056	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1057	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1058	manpage for details.
		1059
		1060	=item aio_pathsync $path, $callback->($status)
		1061
		1062	This request tries to open, fsync and close the given path. This is a
		1063	composite request intended to sync directories after directory operations
		1064	(E.g. rename). This might not work on all operating systems or have any
		1065	specific effect, but usually it makes sure that directory changes get
		1066	written to disc. It works for anything that can be opened for read-only,
		1067	not just directories.
		1068
		1069	Future versions of this function might fall back to other methods when
		1070	C<fsync> on the directory fails (such as calling C<sync>).
		1071
		1072	Passes C<0> when everything went ok, and C<-1> on error.
		1073
		1074	=cut
		1075
		1076	sub aio_pathsync($;$) {
		1077	my ($path, $cb) = @_;
		1078
		1079	my $pri = aioreq_pri;
		1080	my $grp = aio_group $cb;
		1081
		1082	aioreq_pri $pri;
		1083	add $grp aio_open $path, O_RDONLY, 0, sub {
		1084	my ($fh) = @_;
		1085	if ($fh) {
		1086	aioreq_pri $pri;
		1087	add $grp aio_fsync $fh, sub {
		1088	$grp->result ($_[0]);
		1089
		1090	aioreq_pri $pri;
		1091	add $grp aio_close $fh;
		1092	};
		1093	} else {
		1094	$grp->result (-1);
		1095	}
		1096	};
		1097
		1098	$grp
		1099	}
		1100
		1101	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1102
		1103	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1104	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1105	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1106	scalar must only be modified in-place while an aio operation is pending on
		1107	it).
		1108
		1109	It calls the C<msync> function of your OS, if available, with the memory
		1110	area starting at C<$offset> in the string and ending C<$length> bytes
		1111	later. If C<$length> is negative, counts from the end, and if C<$length>
		1112	is C<undef>, then it goes till the end of the string. The flags can be
		1113	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1114	C<IO::AIO::MS_SYNC>.
		1115
		1116	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1117
		1118	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1119	scalars.
		1120
		1121	It touches (reads or writes) all memory pages in the specified
		1122	range inside the scalar. All caveats and parameters are the same
		1123	as for C<aio_msync>, above, except for flags, which must be either
		1124	C<0> (which reads all pages and ensures they are instantiated) or
		1125	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1126	writing an octet from it, which dirties the page).
		1127
		1128	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1129
		1130	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1131	scalars.
		1132
		1133	It reads in all the pages of the underlying storage into memory (if any)
		1134	and locks them, so they are not getting swapped/paged out or removed.
		1135
		1136	If C<$length> is undefined, then the scalar will be locked till the end.
		1137
		1138	On systems that do not implement C<mlock>, this function returns C<-1>
		1139	and sets errno to C<ENOSYS>.
		1140
		1141	Note that the corresponding C<munlock> is synchronous and is
		1142	documented under L<MISCELLANEOUS FUNCTIONS>.
		1143
		1144	Example: open a file, mmap and mlock it - both will be undone when
		1145	C<$data> gets destroyed.
		1146
		1147	open my $fh, "<", $path or die "$path: $!";
		1148	my $data;
		1149	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1150	aio_mlock $data; # mlock in background
		1151
		1152	=item aio_mlockall $flags, $callback->($status)
		1153
		1154	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1155	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1156
		1157	On systems that do not implement C<mlockall>, this function returns C<-1>
		1158	and sets errno to C<ENOSYS>.
		1159
		1160	Note that the corresponding C<munlockall> is synchronous and is
		1161	documented under L<MISCELLANEOUS FUNCTIONS>.
		1162
		1163	Example: asynchronously lock all current and future pages into memory.
		1164
		1165	aio_mlockall IO::AIO::MCL_FUTURE;
709		1166
710	=item aio_group $callback->(...)	1167	=item aio_group $callback->(...)
711		1168
712	This is a very special aio request: Instead of doing something, it is a	1169	This is a very special aio request: Instead of doing something, it is a
713	container for other aio requests, which is useful if you want to bundle	1170	container for other aio requests, which is useful if you want to bundle
…		…
763	=item cancel $req	1220	=item cancel $req
764		1221
765	Cancels the request, if possible. Has the effect of skipping execution	1222	Cancels the request, if possible. Has the effect of skipping execution
766	when entering the B<execute> state and skipping calling the callback when	1223	when entering the B<execute> state and skipping calling the callback when
767	entering the the B<result> state, but will leave the request otherwise	1224	entering the the B<result> state, but will leave the request otherwise
768	untouched. That means that requests that currently execute will not be	1225	untouched (with the exception of readdir). That means that requests that
769	stopped and resources held by the request will not be freed prematurely.	1226	currently execute will not be stopped and resources held by the request
		1227	will not be freed prematurely.
770		1228
771	=item cb $req $callback->(...)	1229	=item cb $req $callback->(...)
772		1230
773	Replace (or simply set) the callback registered to the request.	1231	Replace (or simply set) the callback registered to the request.
774		1232
…		…
825	Their lifetime, simplified, looks like this: when they are empty, they	1283	Their lifetime, simplified, looks like this: when they are empty, they
826	will finish very quickly. If they contain only requests that are in the	1284	will finish very quickly. If they contain only requests that are in the
827	C<done> state, they will also finish. Otherwise they will continue to	1285	C<done> state, they will also finish. Otherwise they will continue to
828	exist.	1286	exist.
829		1287
830	That means after creating a group you have some time to add requests. And	1288	That means after creating a group you have some time to add requests
831	in the callbacks of those requests, you can add further requests to the	1289	(precisely before the callback has been invoked, which is only done within
832	group. And only when all those requests have finished will the the group	1290	the C<poll_cb>). And in the callbacks of those requests, you can add
833	itself finish.	1291	further requests to the group. And only when all those requests have
		1292	finished will the the group itself finish.
834		1293
835	=over 4	1294	=over 4
836		1295
837	=item add $grp ...	1296	=item add $grp ...
838		1297
…		…
847	=item $grp->cancel_subs	1306	=item $grp->cancel_subs
848		1307
849	Cancel all subrequests and clears any feeder, but not the group request	1308	Cancel all subrequests and clears any feeder, but not the group request
850	itself. Useful when you queued a lot of events but got a result early.	1309	itself. Useful when you queued a lot of events but got a result early.
851		1310
		1311	The group request will finish normally (you cannot add requests to the
		1312	group).
		1313
852	=item $grp->result (...)	1314	=item $grp->result (...)
853		1315
854	Set the result value(s) that will be passed to the group callback when all	1316	Set the result value(s) that will be passed to the group callback when all
855	subrequests have finished and set thre groups errno to the current value	1317	subrequests have finished and set the groups errno to the current value
856	of errno (just like calling C<errno> without an error number). By default,	1318	of errno (just like calling C<errno> without an error number). By default,
857	no argument will be passed and errno is zero.	1319	no argument will be passed and errno is zero.
858		1320
859	=item $grp->errno ([$errno])	1321	=item $grp->errno ([$errno])
860		1322
…		…
871	=item feed $grp $callback->($grp)	1333	=item feed $grp $callback->($grp)
872		1334
873	Sets a feeder/generator on this group: every group can have an attached	1335	Sets a feeder/generator on this group: every group can have an attached
874	generator that generates requests if idle. The idea behind this is that,	1336	generator that generates requests if idle. The idea behind this is that,
875	although you could just queue as many requests as you want in a group,	1337	although you could just queue as many requests as you want in a group,
876	this might starve other requests for a potentially long time. For	1338	this might starve other requests for a potentially long time. For example,
877	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1339	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
878	requests, delaying any later requests for a long time.	1340	delaying any later requests for a long time.
879		1341
880	To avoid this, and allow incremental generation of requests, you can	1342	To avoid this, and allow incremental generation of requests, you can
881	instead a group and set a feeder on it that generates those requests. The	1343	instead a group and set a feeder on it that generates those requests. The
882	feed callback will be called whenever there are few enough (see C<limit>,	1344	feed callback will be called whenever there are few enough (see C<limit>,
883	below) requests active in the group itself and is expected to queue more	1345	below) requests active in the group itself and is expected to queue more
…		…
887	not impose any limits).	1349	not impose any limits).
888		1350
889	If the feed does not queue more requests when called, it will be	1351	If the feed does not queue more requests when called, it will be
890	automatically removed from the group.	1352	automatically removed from the group.
891		1353
892	If the feed limit is C<0>, it will be set to C<2> automatically.	1354	If the feed limit is C<0> when this method is called, it will be set to
		1355	C<2> automatically.
893		1356
894	Example:	1357	Example:
895		1358
896	# stat all files in @files, but only ever use four aio requests concurrently:	1359	# stat all files in @files, but only ever use four aio requests concurrently:
897		1360
…		…
909	Sets the feeder limit for the group: The feeder will be called whenever	1372	Sets the feeder limit for the group: The feeder will be called whenever
910	the group contains less than this many requests.	1373	the group contains less than this many requests.
911		1374
912	Setting the limit to C<0> will pause the feeding process.	1375	Setting the limit to C<0> will pause the feeding process.
913		1376
		1377	The default value for the limit is C<0>, but note that setting a feeder
		1378	automatically bumps it up to C<2>.
		1379
914	=back	1380	=back
915		1381
916	=head2 SUPPORT FUNCTIONS	1382	=head2 SUPPORT FUNCTIONS
917		1383
918	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1384	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
920	=over 4	1386	=over 4
921		1387
922	=item $fileno = IO::AIO::poll_fileno	1388	=item $fileno = IO::AIO::poll_fileno
923		1389
924	Return the I<request result pipe file descriptor>. This filehandle must be	1390	Return the I<request result pipe file descriptor>. This filehandle must be
925	polled for reading by some mechanism outside this module (e.g. Event or	1391	polled for reading by some mechanism outside this module (e.g. EV, Glib,
926	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1392	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
927	to call C<poll_cb> to check the results.	1393	you have to call C<poll_cb> to check the results.
928		1394
929	See C<poll_cb> for an example.	1395	See C<poll_cb> for an example.
930		1396
931	=item IO::AIO::poll_cb	1397	=item IO::AIO::poll_cb
932		1398
933	Process some outstanding events on the result pipe. You have to call this	1399	Process some outstanding events on the result pipe. You have to call this
934	regularly. Returns the number of events processed. Returns immediately	1400	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1401	returned earlier for whatever reason. Returns immediately when no events
935	when no events are outstanding. The amount of events processed depends on	1402	are outstanding. The amount of events processed depends on the settings of
936	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1403	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
937		1404
938	If not all requests were processed for whatever reason, the filehandle	1405	If not all requests were processed for whatever reason, the filehandle
939	will still be ready when C<poll_cb> returns.	1406	will still be ready when C<poll_cb> returns, so normally you don't have to
		1407	do anything special to have it called later.
940		1408
941	Example: Install an Event watcher that automatically calls	1409	Example: Install an Event watcher that automatically calls
942	IO::AIO::poll_cb with high priority:	1410	IO::AIO::poll_cb with high priority (more examples can be found in the
		1411	SYNOPSIS section, at the top of this document):
943		1412
944	Event->io (fd => IO::AIO::poll_fileno,	1413	Event->io (fd => IO::AIO::poll_fileno,
945	poll => 'r', async => 1,	1414	poll => 'r', async => 1,
946	cb => \&IO::AIO::poll_cb);	1415	cb => \&IO::AIO::poll_cb);
		1416
		1417	=item IO::AIO::poll_wait
		1418
		1419	If there are any outstanding requests and none of them in the result
		1420	phase, wait till the result filehandle becomes ready for reading (simply
		1421	does a C<select> on the filehandle. This is useful if you want to
		1422	synchronously wait for some requests to finish).
		1423
		1424	See C<nreqs> for an example.
		1425
		1426	=item IO::AIO::poll
		1427
		1428	Waits until some requests have been handled.
		1429
		1430	Returns the number of requests processed, but is otherwise strictly
		1431	equivalent to:
		1432
		1433	IO::AIO::poll_wait, IO::AIO::poll_cb
		1434
		1435	=item IO::AIO::flush
		1436
		1437	Wait till all outstanding AIO requests have been handled.
		1438
		1439	Strictly equivalent to:
		1440
		1441	IO::AIO::poll_wait, IO::AIO::poll_cb
		1442	while IO::AIO::nreqs;
947		1443
948	=item IO::AIO::max_poll_reqs $nreqs	1444	=item IO::AIO::max_poll_reqs $nreqs
949		1445
950	=item IO::AIO::max_poll_time $seconds	1446	=item IO::AIO::max_poll_time $seconds
951		1447
…		…
976	# use a low priority so other tasks have priority	1472	# use a low priority so other tasks have priority
977	Event->io (fd => IO::AIO::poll_fileno,	1473	Event->io (fd => IO::AIO::poll_fileno,
978	poll => 'r', nice => 1,	1474	poll => 'r', nice => 1,
979	cb => &IO::AIO::poll_cb);	1475	cb => &IO::AIO::poll_cb);
980		1476
981	=item IO::AIO::poll_wait	1477	=back
982
983	If there are any outstanding requests and none of them in the result
984	phase, wait till the result filehandle becomes ready for reading (simply
985	does a C<select> on the filehandle. This is useful if you want to
986	synchronously wait for some requests to finish).
987
988	See C<nreqs> for an example.
989
990	=item IO::AIO::poll
991
992	Waits until some requests have been handled.
993
994	Returns the number of requests processed, but is otherwise strictly
995	equivalent to:
996
997	IO::AIO::poll_wait, IO::AIO::poll_cb
998
999	=item IO::AIO::flush
1000
1001	Wait till all outstanding AIO requests have been handled.
1002
1003	Strictly equivalent to:
1004
1005	IO::AIO::poll_wait, IO::AIO::poll_cb
1006	while IO::AIO::nreqs;
1007		1478
1008	=head3 CONTROLLING THE NUMBER OF THREADS	1479	=head3 CONTROLLING THE NUMBER OF THREADS
		1480
		1481	=over
1009		1482
1010	=item IO::AIO::min_parallel $nthreads	1483	=item IO::AIO::min_parallel $nthreads
1011		1484
1012	Set the minimum number of AIO threads to C<$nthreads>. The current	1485	Set the minimum number of AIO threads to C<$nthreads>. The current
1013	default is C<8>, which means eight asynchronous operations can execute	1486	default is C<8>, which means eight asynchronous operations can execute
…		…
1054		1527
1055	The default is probably ok in most situations, especially if thread	1528	The default is probably ok in most situations, especially if thread
1056	creation is fast. If thread creation is very slow on your system you might	1529	creation is fast. If thread creation is very slow on your system you might
1057	want to use larger values.	1530	want to use larger values.
1058		1531
1059	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1532	=item IO::AIO::max_outstanding $maxreqs
1060		1533
1061	This is a very bad function to use in interactive programs because it	1534	This is a very bad function to use in interactive programs because it
1062	blocks, and a bad way to reduce concurrency because it is inexact: Better	1535	blocks, and a bad way to reduce concurrency because it is inexact: Better
1063	use an C<aio_group> together with a feed callback.	1536	use an C<aio_group> together with a feed callback.
1064		1537
1065	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1538	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1066	to queue up more than this number of requests, the next call to the	1539	do queue up more than this number of requests, the next call to the
1067	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1540	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1068	function will block until the limit is no longer exceeded.	1541	function will block until the limit is no longer exceeded.
1069		1542
1070	The default value is very large, so there is no practical limit on the	1543	The default value is very large, so there is no practical limit on the
1071	number of outstanding requests.	1544	number of outstanding requests.
1072		1545
1073	You can still queue as many requests as you want. Therefore,	1546	You can still queue as many requests as you want. Therefore,
1074	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1547	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1075	as a stop gap to shield against fatal memory overflow (with large values).	1548	as a stop gap to shield against fatal memory overflow (with large values).
1076		1549
		1550	=back
		1551
1077	=head3 STATISTICAL INFORMATION	1552	=head3 STATISTICAL INFORMATION
		1553
		1554	=over
1078		1555
1079	=item IO::AIO::nreqs	1556	=item IO::AIO::nreqs
1080		1557
1081	Returns the number of requests currently in the ready, execute or pending	1558	Returns the number of requests currently in the ready, execute or pending
1082	states (i.e. for which their callback has not been invoked yet).	1559	states (i.e. for which their callback has not been invoked yet).
…		…
1096	Returns the number of requests currently in the pending state (executed,	1573	Returns the number of requests currently in the pending state (executed,
1097	but not yet processed by poll_cb).	1574	but not yet processed by poll_cb).
1098		1575
1099	=back	1576	=back
1100		1577
		1578	=head3 MISCELLANEOUS FUNCTIONS
		1579
		1580	IO::AIO implements some functions that might be useful, but are not
		1581	asynchronous.
		1582
		1583	=over 4
		1584
		1585	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1586
		1587	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1588	but is blocking (this makes most sense if you know the input data is
		1589	likely cached already and the output filehandle is set to non-blocking
		1590	operations).
		1591
		1592	Returns the number of bytes copied, or C<-1> on error.
		1593
		1594	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1595
		1596	Simply calls the C<posix_fadvise> function (see its
		1597	manpage for details). The following advice constants are
		1598	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1599	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1600	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1601
		1602	On systems that do not implement C<posix_fadvise>, this function returns
		1603	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1604
		1605	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1606
		1607	Simply calls the C<posix_madvise> function (see its
		1608	manpage for details). The following advice constants are
		1609	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1610	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1611
		1612	On systems that do not implement C<posix_madvise>, this function returns
		1613	ENOSYS, otherwise the return value of C<posix_madvise>.
		1614
		1615	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1616
		1617	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1618	$scalar (see its manpage for details). The following protect
		1619	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1620	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1621
		1622	On systems that do not implement C<mprotect>, this function returns
		1623	ENOSYS, otherwise the return value of C<mprotect>.
		1624
		1625	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1626
		1627	Memory-maps a file (or anonymous memory range) and attaches it to the
		1628	given C<$scalar>, which will act like a string scalar.
		1629
		1630	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1631	change the string length, and most read-only operations such as copying it
		1632	or searching it with regexes and so on.
		1633
		1634	Anything else is unsafe and will, at best, result in memory leaks.
		1635
		1636	The memory map associated with the C<$scalar> is automatically removed
		1637	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1638	C<IO::AIO::munmap> functions are called.
		1639
		1640	This calls the C<mmap>(2) function internally. See your system's manual
		1641	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1642
		1643	The C<$length> must be larger than zero and smaller than the actual
		1644	filesize.
		1645
		1646	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1647	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1648
		1649	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1650	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1651	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1652	(which is set to C<MAP_ANON> if your system only provides this
		1653	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1654	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1655	C<IO::AIO::MAP_NONBLOCK>
		1656
		1657	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1658
		1659	C<$offset> is the offset from the start of the file - it generally must be
		1660	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1661
		1662	Example:
		1663
		1664	use Digest::MD5;
		1665	use IO::AIO;
		1666
		1667	open my $fh, "<verybigfile"
		1668	or die "$!";
		1669
		1670	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1671	or die "verybigfile: $!";
		1672
		1673	my $fast_md5 = md5 $data;
		1674
		1675	=item IO::AIO::munmap $scalar
		1676
		1677	Removes a previous mmap and undefines the C<$scalar>.
		1678
		1679	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1680
		1681	Calls the C<munlock> function, undoing the effects of a previous
		1682	C<aio_mlock> call (see its description for details).
		1683
		1684	=item IO::AIO::munlockall
		1685
		1686	Calls the C<munlockall> function.
		1687
		1688	On systems that do not implement C<munlockall>, this function returns
		1689	ENOSYS, otherwise the return value of C<munlockall>.
		1690
		1691	=back
		1692
1101	=cut	1693	=cut
1102		1694
1103	# support function to convert a fd into a perl filehandle
1104	sub _fd2fh {
1105	return undef if $_[0] < 0;
1106
1107	# try to generate nice filehandles
1108	my $sym = "IO::AIO::fd#$_[0]";
1109	local *$sym;
1110
1111	open *$sym, "+<&=$_[0]" # usually works under any unix
1112	or open *$sym, "<&=$_[0]" # cygwin needs this
1113	or open *$sym, ">&=$_[0]" # or this
1114	or return undef;
1115
1116	*$sym
1117	}
1118
1119	min_parallel 8;	1695	min_parallel 8;
1120		1696
1121	END { flush }	1697	END { flush }
1122		1698
1123	1;	1699	1;
		1700
		1701	=head1 EVENT LOOP INTEGRATION
		1702
		1703	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1704	automatically into many event loops:
		1705
		1706	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1707	use AnyEvent::AIO;
		1708
		1709	You can also integrate IO::AIO manually into many event loops, here are
		1710	some examples of how to do this:
		1711
		1712	# EV integration
		1713	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1714
		1715	# Event integration
		1716	Event->io (fd => IO::AIO::poll_fileno,
		1717	poll => 'r',
		1718	cb => \&IO::AIO::poll_cb);
		1719
		1720	# Glib/Gtk2 integration
		1721	add_watch Glib::IO IO::AIO::poll_fileno,
		1722	in => sub { IO::AIO::poll_cb; 1 };
		1723
		1724	# Tk integration
		1725	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1726	readable => \&IO::AIO::poll_cb);
		1727
		1728	# Danga::Socket integration
		1729	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1730	\&IO::AIO::poll_cb);
1124		1731
1125	=head2 FORK BEHAVIOUR	1732	=head2 FORK BEHAVIOUR
1126		1733
1127	This module should do "the right thing" when the process using it forks:	1734	This module should do "the right thing" when the process using it forks:
1128		1735
…		…
1146	bytes of memory. In addition, stat requests need a stat buffer (possibly	1753	bytes of memory. In addition, stat requests need a stat buffer (possibly
1147	a few hundred bytes), readdir requires a result buffer and so on. Perl	1754	a few hundred bytes), readdir requires a result buffer and so on. Perl
1148	scalars and other data passed into aio requests will also be locked and	1755	scalars and other data passed into aio requests will also be locked and
1149	will consume memory till the request has entered the done state.	1756	will consume memory till the request has entered the done state.
1150		1757
1151	This is now awfully much, so queuing lots of requests is not usually a	1758	This is not awfully much, so queuing lots of requests is not usually a
1152	problem.	1759	problem.
1153		1760
1154	Per-thread usage:	1761	Per-thread usage:
1155		1762
1156	In the execution phase, some aio requests require more memory for	1763	In the execution phase, some aio requests require more memory for
…		…
1161		1768
1162	Known bugs will be fixed in the next release.	1769	Known bugs will be fixed in the next release.
1163		1770
1164	=head1 SEE ALSO	1771	=head1 SEE ALSO
1165		1772
1166	L<Coro::AIO>.	1773	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1774	more natural syntax.
1167		1775
1168	=head1 AUTHOR	1776	=head1 AUTHOR
1169		1777
1170	Marc Lehmann <schmorp@schmorp.de>	1778	Marc Lehmann <schmorp@schmorp.de>
1171	http://home.schmorp.de/	1779	http://home.schmorp.de/

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