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Revision 1.88 by root, Sun Oct 29 01:50:29 2006 UTC vs.
Revision 1.187 by root, Fri Feb 11 00:05:17 2011 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my ($fh) = @_;	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>).
55		36
56	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
57	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
58	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
59	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
61	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
62	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
63	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
64	concurrently.	45	concurrently.
65		46
66	While this works on all types of file descriptors (for example sockets),	47	While most of this works on all types of file descriptors (for
67	using these functions on file descriptors that support nonblocking	48	example sockets), using these functions on file descriptors that
68	operation (again, sockets, pipes etc.) is very inefficient. Use an event	49	support nonblocking operation (again, sockets, pipes etc.) is
69	loop for that (such as the L<Event|Event> module): IO::AIO will naturally	50	very inefficient. Use an event loop for that (such as the L<EV>
70	fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
71		52
72	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
73	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
74	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
75	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
…		…
77	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
78	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
79	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
80	using threads anyway.	61	using threads anyway.
81		62
82	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,
83	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
84	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
85	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
86		67
87	=head2 EXAMPLE	68	=head2 EXAMPLE
88		69
89	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
90	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
91		72
92	use Fcntl;	73	use Fcntl;
93	use Event;	74	use EV;
94	use IO::AIO;	75	use IO::AIO;
95		76
96	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
97	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
98	poll => 'r',
99	cb => \&IO::AIO::poll_cb);
100		79
101	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
102	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
103	my $fh = $_[0]	82	my $fh = shift
104	or die "error while opening: $!";	83	or die "error while opening: $!";
105		84
106	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
107	my $size = -s $fh;	86	my $size = -s $fh;
108		87
…		…
116		95
117	# file contents now in $contents	96	# file contents now in $contents
118	print $contents;	97	print $contents;
119		98
120	# exit event loop and program	99	# exit event loop and program
121	Event::unloop;	100	EV::unloop;
122	};	101	};
123	};	102	};
124		103
125	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
126	# check for sockets etc. etc.	105	# check for sockets etc. etc.
127		106
128	# process events as long as there are some:	107	# process events as long as there are some:
129	Event::loop;	108	EV::loop;
130		109
131	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
132		111
133	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
134	directly visible to Perl.	113	directly visible to Perl.
…		…
182		161
183	=cut	162	=cut
184		163
185	package IO::AIO;	164	package IO::AIO;
186		165
187	no warnings;	166	use Carp ();
188	use strict 'vars';	167
		168	use common::sense;
189		169
190	use base 'Exporter';	170	use base 'Exporter';
191		171
192	BEGIN {	172	BEGIN {
193	our $VERSION = '2.1';	173	our $VERSION = '3.72';
194		174
195	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
196	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
197	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
198	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
199	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
200	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
201	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle
202	nreqs nready npending nthreads	188	nreqs nready npending nthreads
203	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
204		194
205	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
206		196
207	require XSLoader;	197	require XSLoader;
208	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
209	}	199	}
210		200
211	=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, $length = undef
		273	IO::AIO::munlockall
212		274
213	=head2 AIO REQUEST FUNCTIONS	275	=head2 AIO REQUEST FUNCTIONS
214		276
215	All the C<aio_*> calls are more or less thin wrappers around the syscall	277	All the C<aio_*> calls are more or less thin wrappers around the syscall
216	with the same name (sans C<aio_>). The arguments are similar or identical,	278	with the same name (sans C<aio_>). The arguments are similar or identical,
217	and they all accept an additional (and optional) C<$callback> argument	279	and they all accept an additional (and optional) C<$callback> argument
218	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
219	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
220	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
221	syscall has been executed asynchronously.	283	syscall has been executed asynchronously.
222		284
223	All functions expecting a filehandle keep a copy of the filehandle	285	All functions expecting a filehandle keep a copy of the filehandle
224	internally until the request has finished.	286	internally until the request has finished.
225		287
…		…
239	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
240	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)
241	use something else to ensure your scalar has the correct contents.	303	use something else to ensure your scalar has the correct contents.
242		304
243	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
244	handles correctly wether it is set or not.	306	handles correctly whether it is set or not.
245		307
246	=over 4	308	=over 4
247		309
248	=item $prev_pri = aioreq_pri [$pri]	310	=item $prev_pri = aioreq_pri [$pri]
249		311
…		…
269	aio_read $_[0], ..., sub {	331	aio_read $_[0], ..., sub {
270	...	332	...
271	};	333	};
272	};	334	};
273		335
		336
274	=item aioreq_nice $pri_adjust	337	=item aioreq_nice $pri_adjust
275		338
276	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
277	priority, so the effect is cumulative.	340	priority, so the effect is cumulative.
		341
278		342
279	=item aio_open $pathname, $flags, $mode, $callback->($fh)	343	=item aio_open $pathname, $flags, $mode, $callback->($fh)
280		344
281	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
282	created filehandle for the file.	346	created filehandle for the file.
…		…
288	list. They are the same as used by C<sysopen>.	352	list. They are the same as used by C<sysopen>.
289		353
290	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
291	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>,
292	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,
293	and C<0666> or C<0777> if you do).	357	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		358	by the umask in effect then the request is being executed, so better never
		359	change the umask.
294		360
295	Example:	361	Example:
296		362
297	aio_open "/etc/passwd", O_RDONLY, 0, sub {	363	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
298	if ($_[0]) {	364	if ($_[0]) {
299	print "open successful, fh is $_[0]\n";	365	print "open successful, fh is $_[0]\n";
300	...	366	...
301	} else {	367	} else {
302	die "open failed: $!\n";	368	die "open failed: $!\n";
303	}	369	}
304	};	370	};
305		371
		372
306	=item aio_close $fh, $callback->($status)	373	=item aio_close $fh, $callback->($status)
307		374
308	Asynchronously close a file and call the callback with the result	375	Asynchronously close a file and call the callback with the result
309	code. I<WARNING:> although accepted, you should not pass in a perl	376	code.
310	filehandle here, as perl will likely close the file descriptor another
311	time when the filehandle is destroyed. Normally, you can safely call perls
312	C<close> or just let filehandles go out of scope.
313		377
314	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
315	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
316		389
317	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	390	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
318		391
319	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	392	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320		393
321	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
322	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<$dataoffset>
323	callback without the actual number of bytes read (or -1 on error, just	396	and calls the callback without the actual number of bytes read (or -1 on
324	like the syscall).	397	error, just like the syscall).
		398
		399	C<aio_read> will, like C<sysread>, shrink or grow the C<$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<$data>.
325		411
326	The C<$data> scalar I<MUST NOT> be modified in any way while the request	412	The C<$data> scalar I<MUST NOT> be modified in any way while the request
327	is outstanding. Modifying it can result in segfaults or WW3 (if the	413	is outstanding. Modifying it can result in segfaults or World War III (if
328	necessary/optional hardware is installed).	414	the necessary/optional hardware is installed).
329		415
330	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	416	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
331	offset C<0> within the scalar:	417	offset C<0> within the scalar:
332		418
333	aio_read $fh, 7, 15, $buffer, 0, sub {	419	aio_read $fh, 7, 15, $buffer, 0, sub {
334	$_[0] > 0 or die "read error: $!";	420	$_[0] > 0 or die "read error: $!";
335	print "read $_[0] bytes: <$buffer>\n";	421	print "read $_[0] bytes: <$buffer>\n";
336	};	422	};
		423
337		424
338	=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)
339		426
340	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
341	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
342	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
343	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
344	other.	431	other.
345		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<$in_fh>) is a file - the file I/O will then be asynchronous, while
		442	the socket I/O will be non-blocking. Note, however, that you can run into
		443	a trap where C<aio_sendfile> reads some data with readahead, then fails
		444	to write all data, and when the socket is ready the next time, the data
		445	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		446	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		447	much better.
		448
346	This call tries to make use of a native C<sendfile> syscall to provide	449	This call tries to make use of a native C<sendfile> syscall to provide
347	zero-copy operation. For this to work, C<$out_fh> should refer to a	450	zero-copy operation. For this to work, C<$out_fh> should refer to a
348	socket, and C<$in_fh> should refer to mmap'able file.	451	socket, and C<$in_fh> should refer to an mmap'able file.
349		452
350	If the native sendfile call fails or is not implemented, it will be	453	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		454	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
351	emulated, so you can call C<aio_sendfile> on any type of filehandle	455	it will be emulated, so you can call C<aio_sendfile> on any type of
352	regardless of the limitations of the operating system.	456	filehandle regardless of the limitations of the operating system.
353		457
354	Please note, however, that C<aio_sendfile> can read more bytes from
355	C<$in_fh> than are written, and there is no way to find out how many
356	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
357	provides the number of bytes written to C<$out_fh>. Only if the result
358	value equals C<$length> one can assume that C<$length> bytes have been
359	read.
360		458
361	=item aio_readahead $fh,$offset,$length, $callback->($retval)	459	=item aio_readahead $fh,$offset,$length, $callback->($retval)
362		460
363	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
364	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>
…		…
370	file. The current file offset of the file is left unchanged.	468	file. The current file offset of the file is left unchanged.
371		469
372	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
373	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.
374		472
		473
375	=item aio_stat $fh_or_path, $callback->($status)	474	=item aio_stat $fh_or_path, $callback->($status)
376		475
377	=item aio_lstat $fh, $callback->($status)	476	=item aio_lstat $fh, $callback->($status)
378		477
379	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
…		…
384	for an explanation.	483	for an explanation.
385		484
386	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	485	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
387	error when stat'ing a large file, the results will be silently truncated	486	error when stat'ing a large file, the results will be silently truncated
388	unless perl itself is compiled with large file support.	487	unless perl itself is compiled with large file support.
		488
		489	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		490	following constants and functions (if not implemented, the constants will
		491	be C<0> and the functions will either C<croak> or fall back on traditional
		492	behaviour).
		493
		494	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		495	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		496	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
389		497
390	Example: Print the length of F</etc/passwd>:	498	Example: Print the length of F</etc/passwd>:
391		499
392	aio_stat "/etc/passwd", sub {	500	aio_stat "/etc/passwd", sub {
393	$_[0] and die "stat failed: $!";	501	$_[0] and die "stat failed: $!";
394	print "size is ", -s _, "\n";	502	print "size is ", -s _, "\n";
395	};	503	};
396		504
		505
		506	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		507
		508	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		509	whether a file handle or path was passed.
		510
		511	On success, the callback is passed a hash reference with the following
		512	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		513	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		514	is passed.
		515
		516	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		517	C<ST_NOSUID>.
		518
		519	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		520	their correct value when available, or to C<0> on systems that do
		521	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		522	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		523	C<ST_NODIRATIME> and C<ST_RELATIME>.
		524
		525	Example: stat C</wd> and dump out the data if successful.
		526
		527	aio_statvfs "/wd", sub {
		528	my $f = $_[0]
		529	or die "statvfs: $!";
		530
		531	use Data::Dumper;
		532	say Dumper $f;
		533	};
		534
		535	# result:
		536	{
		537	bsize => 1024,
		538	bfree => 4333064312,
		539	blocks => 10253828096,
		540	files => 2050765568,
		541	flag => 4096,
		542	favail => 2042092649,
		543	bavail => 4333064312,
		544	ffree => 2042092649,
		545	namemax => 255,
		546	frsize => 1024,
		547	fsid => 1810
		548	}
		549
		550
		551	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		552
		553	Works like perl's C<utime> function (including the special case of $atime
		554	and $mtime being undef). Fractional times are supported if the underlying
		555	syscalls support them.
		556
		557	When called with a pathname, uses utimes(2) if available, otherwise
		558	utime(2). If called on a file descriptor, uses futimes(2) if available,
		559	otherwise returns ENOSYS, so this is not portable.
		560
		561	Examples:
		562
		563	# set atime and mtime to current time (basically touch(1)):
		564	aio_utime "path", undef, undef;
		565	# set atime to current time and mtime to beginning of the epoch:
		566	aio_utime "path", time, undef; # undef==0
		567
		568
		569	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		570
		571	Works like perl's C<chown> function, except that C<undef> for either $uid
		572	or $gid is being interpreted as "do not change" (but -1 can also be used).
		573
		574	Examples:
		575
		576	# same as "chown root path" in the shell:
		577	aio_chown "path", 0, -1;
		578	# same as above:
		579	aio_chown "path", 0, undef;
		580
		581
		582	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		583
		584	Works like truncate(2) or ftruncate(2).
		585
		586
		587	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		588
		589	Works like perl's C<chmod> function.
		590
		591
397	=item aio_unlink $pathname, $callback->($status)	592	=item aio_unlink $pathname, $callback->($status)
398		593
399	Asynchronously unlink (delete) a file and call the callback with the	594	Asynchronously unlink (delete) a file and call the callback with the
400	result code.	595	result code.
401		596
		597
402	=item aio_mknod $path, $mode, $dev, $callback->($status)	598	=item aio_mknod $path, $mode, $dev, $callback->($status)
403		599
404	[EXPERIMENTAL]	600	[EXPERIMENTAL]
405		601
406	Asynchronously create a device node (or fifo). See mknod(2).	602	Asynchronously create a device node (or fifo). See mknod(2).
407		603
408	The only (POSIX-) portable way of calling this function is:	604	The only (POSIX-) portable way of calling this function is:
409		605
410	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	606	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		607
		608	See C<aio_stat> for info about some potentially helpful extra constants
		609	and functions.
411		610
412	=item aio_link $srcpath, $dstpath, $callback->($status)	611	=item aio_link $srcpath, $dstpath, $callback->($status)
413		612
414	Asynchronously create a new link to the existing object at C<$srcpath> at	613	Asynchronously create a new link to the existing object at C<$srcpath> at
415	the path C<$dstpath> and call the callback with the result code.	614	the path C<$dstpath> and call the callback with the result code.
416		615
		616
417	=item aio_symlink $srcpath, $dstpath, $callback->($status)	617	=item aio_symlink $srcpath, $dstpath, $callback->($status)
418		618
419	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	619	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
420	the path C<$dstpath> and call the callback with the result code.	620	the path C<$dstpath> and call the callback with the result code.
421		621
		622
		623	=item aio_readlink $path, $callback->($link)
		624
		625	Asynchronously read the symlink specified by C<$path> and pass it to
		626	the callback. If an error occurs, nothing or undef gets passed to the
		627	callback.
		628
		629
422	=item aio_rename $srcpath, $dstpath, $callback->($status)	630	=item aio_rename $srcpath, $dstpath, $callback->($status)
423		631
424	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	632	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
425	rename(2) and call the callback with the result code.	633	rename(2) and call the callback with the result code.
426		634
		635
		636	=item aio_mkdir $pathname, $mode, $callback->($status)
		637
		638	Asynchronously mkdir (create) a directory and call the callback with
		639	the result code. C<$mode> will be modified by the umask at the time the
		640	request is executed, so do not change your umask.
		641
		642
427	=item aio_rmdir $pathname, $callback->($status)	643	=item aio_rmdir $pathname, $callback->($status)
428		644
429	Asynchronously rmdir (delete) a directory and call the callback with the	645	Asynchronously rmdir (delete) a directory and call the callback with the
430	result code.	646	result code.
		647
431		648
432	=item aio_readdir $pathname, $callback->($entries)	649	=item aio_readdir $pathname, $callback->($entries)
433		650
434	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	651	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
435	directory (i.e. opendir + readdir + closedir). The entries will not be	652	directory (i.e. opendir + readdir + closedir). The entries will not be
436	sorted, and will B<NOT> include the C<.> and C<..> entries.	653	sorted, and will B<NOT> include the C<.> and C<..> entries.
437		654
438	The callback a single argument which is either C<undef> or an array-ref	655	The callback is passed a single argument which is either C<undef> or an
439	with the filenames.	656	array-ref with the filenames.
		657
		658
		659	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		660
		661	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		662	behaviour and output format. In case of an error, C<$entries> will be
		663	C<undef>.
		664
		665	The flags are a combination of the following constants, ORed together (the
		666	flags will also be passed to the callback, possibly modified):
		667
		668	=over 4
		669
		670	=item IO::AIO::READDIR_DENTS
		671
		672	When this flag is off, then the callback gets an arrayref with of names
		673	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		674	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		675	entry in more detail.
		676
		677	C<$name> is the name of the entry.
		678
		679	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		680
		681	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		682	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		683	C<IO::AIO::DT_WHT>.
		684
		685	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		686	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		687	scalars are read-only: you can not modify them.
		688
		689	C<$inode> is the inode number (which might not be exact on systems with 64
		690	bit inode numbers and 32 bit perls). This field has unspecified content on
		691	systems that do not deliver the inode information.
		692
		693	=item IO::AIO::READDIR_DIRS_FIRST
		694
		695	When this flag is set, then the names will be returned in an order where
		696	likely directories come first. This is useful when you need to quickly
		697	find directories, or you want to find all directories while avoiding to
		698	stat() each entry.
		699
		700	If the system returns type information in readdir, then this is used
		701	to find directories directly. Otherwise, likely directories are files
		702	beginning with ".", or otherwise files with no dots, of which files with
		703	short names are tried first.
		704
		705	=item IO::AIO::READDIR_STAT_ORDER
		706
		707	When this flag is set, then the names will be returned in an order
		708	suitable for stat()'ing each one. That is, when you plan to stat()
		709	all files in the given directory, then the returned order will likely
		710	be fastest.
		711
		712	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		713	the likely dirs come first, resulting in a less optimal stat order.
		714
		715	=item IO::AIO::READDIR_FOUND_UNKNOWN
		716
		717	This flag should not be set when calling C<aio_readdirx>. Instead, it
		718	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		719	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		720	C<$type>'s are known, which can be used to speed up some algorithms.
		721
		722	=back
		723
		724
		725	=item aio_load $path, $data, $callback->($status)
		726
		727	This is a composite request that tries to fully load the given file into
		728	memory. Status is the same as with aio_read.
		729
		730	=cut
		731
		732	sub aio_load($$;$) {
		733	my ($path, undef, $cb) = @_;
		734	my $data = \$_[1];
		735
		736	my $pri = aioreq_pri;
		737	my $grp = aio_group $cb;
		738
		739	aioreq_pri $pri;
		740	add $grp aio_open $path, O_RDONLY, 0, sub {
		741	my $fh = shift
		742	or return $grp->result (-1);
		743
		744	aioreq_pri $pri;
		745	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		746	$grp->result ($_[0]);
		747	};
		748	};
		749
		750	$grp
		751	}
440		752
441	=item aio_copy $srcpath, $dstpath, $callback->($status)	753	=item aio_copy $srcpath, $dstpath, $callback->($status)
442		754
443	Try to copy the I<file> (directories not supported as either source or	755	Try to copy the I<file> (directories not supported as either source or
444	destination) from C<$srcpath> to C<$dstpath> and call the callback with	756	destination) from C<$srcpath> to C<$dstpath> and call the callback with
445	the C<0> (error) or C<-1> ok.	757	a status of C<0> (ok) or C<-1> (error, see C<$!>).
446		758
447	This is a composite request that it creates the destination file with	759	This is a composite request that creates the destination file with
448	mode 0200 and copies the contents of the source file into it using	760	mode 0200 and copies the contents of the source file into it using
449	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	761	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
450	uid/gid, in that order.	762	uid/gid, in that order.
451		763
452	If an error occurs, the partial destination file will be unlinked, if	764	If an error occurs, the partial destination file will be unlinked, if
…		…
462	my $grp = aio_group $cb;	774	my $grp = aio_group $cb;
463		775
464	aioreq_pri $pri;	776	aioreq_pri $pri;
465	add $grp aio_open $src, O_RDONLY, 0, sub {	777	add $grp aio_open $src, O_RDONLY, 0, sub {
466	if (my $src_fh = $_[0]) {	778	if (my $src_fh = $_[0]) {
467	my @stat = stat $src_fh;	779	my @stat = stat $src_fh; # hmm, might block over nfs?
468		780
469	aioreq_pri $pri;	781	aioreq_pri $pri;
470	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	782	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
471	if (my $dst_fh = $_[0]) {	783	if (my $dst_fh = $_[0]) {
472	aioreq_pri $pri;	784	aioreq_pri $pri;
473	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	785	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
474	if ($_[0] == $stat[7]) {	786	if ($_[0] == $stat[7]) {
475	$grp->result (0);	787	$grp->result (0);
476	close $src_fh;	788	close $src_fh;
477		789
478	# those should not normally block. should. should.	790	my $ch = sub {
		791	aioreq_pri $pri;
		792	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		793	aioreq_pri $pri;
		794	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		795	aioreq_pri $pri;
		796	add $grp aio_close $dst_fh;
		797	}
		798	};
		799	};
		800
		801	aioreq_pri $pri;
		802	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		803	if ($_[0] < 0 && $! == ENOSYS) {
		804	aioreq_pri $pri;
479	utime $stat[8], $stat[9], $dst;	805	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
480	chmod $stat[2] & 07777, $dst_fh;	806	} else {
481	chown $stat[4], $stat[5], $dst_fh;	807	$ch->();
		808	}
482	close $dst_fh;	809	};
483	} else {	810	} else {
484	$grp->result (-1);	811	$grp->result (-1);
485	close $src_fh;	812	close $src_fh;
486	close $dst_fh;	813	close $dst_fh;
487		814
…		…
504		831
505	=item aio_move $srcpath, $dstpath, $callback->($status)	832	=item aio_move $srcpath, $dstpath, $callback->($status)
506		833
507	Try to move the I<file> (directories not supported as either source or	834	Try to move the I<file> (directories not supported as either source or
508	destination) from C<$srcpath> to C<$dstpath> and call the callback with	835	destination) from C<$srcpath> to C<$dstpath> and call the callback with
509	the C<0> (error) or C<-1> ok.	836	a status of C<0> (ok) or C<-1> (error, see C<$!>).
510		837
511	This is a composite request that tries to rename(2) the file first. If	838	This is a composite request that tries to rename(2) the file first; if
512	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	839	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
513	that is successful, unlinking the C<$srcpath>.	840	that is successful, unlinks the C<$srcpath>.
514		841
515	=cut	842	=cut
516		843
517	sub aio_move($$;$) {	844	sub aio_move($$;$) {
518	my ($src, $dst, $cb) = @_;	845	my ($src, $dst, $cb) = @_;
…		…
565		892
566	Implementation notes.	893	Implementation notes.
567		894
568	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	895	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
569		896
		897	If readdir returns file type information, then this is used directly to
		898	find directories.
		899
570	After reading the directory, the modification time, size etc. of the	900	Otherwise, after reading the directory, the modification time, size etc.
571	directory before and after the readdir is checked, and if they match (and	901	of the directory before and after the readdir is checked, and if they
572	isn't the current time), the link count will be used to decide how many	902	match (and isn't the current time), the link count will be used to decide
573	entries are directories (if >= 2). Otherwise, no knowledge of the number	903	how many entries are directories (if >= 2). Otherwise, no knowledge of the
574	of subdirectories will be assumed.	904	number of subdirectories will be assumed.
575		905
576	Then entries will be sorted into likely directories (everything without	906	Then entries will be sorted into likely directories a non-initial dot
577	a non-initial dot currently) and likely non-directories (everything	907	currently) and likely non-directories (see C<aio_readdirx>). Then every
578	else). Then every entry plus an appended C</.> will be C<stat>'ed,	908	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
579	likely directories first. If that succeeds, it assumes that the entry	909	in order of their inode numbers. If that succeeds, it assumes that the
580	is a directory or a symlink to directory (which will be checked	910	entry is a directory or a symlink to directory (which will be checked
581	seperately). This is often faster than stat'ing the entry itself because	911	seperately). This is often faster than stat'ing the entry itself because
582	filesystems might detect the type of the entry without reading the inode	912	filesystems might detect the type of the entry without reading the inode
583	data (e.g. ext2fs filetype feature).	913	data (e.g. ext2fs filetype feature), even on systems that cannot return
		914	the filetype information on readdir.
584		915
585	If the known number of directories (link count - 2) has been reached, the	916	If the known number of directories (link count - 2) has been reached, the
586	rest of the entries is assumed to be non-directories.	917	rest of the entries is assumed to be non-directories.
587		918
588	This only works with certainty on POSIX (= UNIX) filesystems, which	919	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
592	as those tend to return 0 or 1 as link counts, which disables the	923	as those tend to return 0 or 1 as link counts, which disables the
593	directory counting heuristic.	924	directory counting heuristic.
594		925
595	=cut	926	=cut
596		927
597	sub aio_scandir($$$) {	928	sub aio_scandir($$;$) {
598	my ($path, $maxreq, $cb) = @_;	929	my ($path, $maxreq, $cb) = @_;
599		930
600	my $pri = aioreq_pri;	931	my $pri = aioreq_pri;
601		932
602	my $grp = aio_group $cb;	933	my $grp = aio_group $cb;
…		…
610	my $now = time;	941	my $now = time;
611	my $hash1 = join ":", (stat _)[0,1,3,7,9];	942	my $hash1 = join ":", (stat _)[0,1,3,7,9];
612		943
613	# read the directory entries	944	# read the directory entries
614	aioreq_pri $pri;	945	aioreq_pri $pri;
615	add $grp aio_readdir $path, sub {	946	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
616	my $entries = shift	947	my $entries = shift
617	or return $grp->result ();	948	or return $grp->result ();
618		949
619	# stat the dir another time	950	# stat the dir another time
620	aioreq_pri $pri;	951	aioreq_pri $pri;
…		…
626	# take the slow route if anything looks fishy	957	# take the slow route if anything looks fishy
627	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	958	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
628	$ndirs = -1;	959	$ndirs = -1;
629	} else {	960	} else {
630	# if nlink == 2, we are finished	961	# if nlink == 2, we are finished
631	# on non-posix-fs's, we rely on nlink < 2	962	# for non-posix-fs's, we rely on nlink < 2
632	$ndirs = (stat _)[3] - 2	963	$ndirs = (stat _)[3] - 2
633	or return $grp->result ([], $entries);	964	or return $grp->result ([], $entries);
634	}	965	}
635		966
636	# sort into likely dirs and likely nondirs
637	# dirs == files without ".", short entries first
638	$entries = [map $_->[0],
639	sort { $b->[1] cmp $a->[1] }
640	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
641	@$entries];
642
643	my (@dirs, @nondirs);	967	my (@dirs, @nondirs);
644		968
645	my $statgrp = add $grp aio_group sub {	969	my $statgrp = add $grp aio_group sub {
646	$grp->result (\@dirs, \@nondirs);	970	$grp->result (\@dirs, \@nondirs);
647	};	971	};
648		972
649	limit $statgrp $maxreq;	973	limit $statgrp $maxreq;
650	feed $statgrp sub {	974	feed $statgrp sub {
651	return unless @$entries;	975	return unless @$entries;
652	my $entry = pop @$entries;	976	my $entry = shift @$entries;
653		977
654	aioreq_pri $pri;	978	aioreq_pri $pri;
655	add $statgrp aio_stat "$path/$entry/.", sub {	979	add $statgrp aio_stat "$path/$entry/.", sub {
656	if ($_[0] < 0) {	980	if ($_[0] < 0) {
657	push @nondirs, $entry;	981	push @nondirs, $entry;
…		…
678	};	1002	};
679		1003
680	$grp	1004	$grp
681	}	1005	}
682		1006
		1007	=item aio_rmtree $path, $callback->($status)
		1008
		1009	Delete a directory tree starting (and including) C<$path>, return the
		1010	status of the final C<rmdir> only. This is a composite request that
		1011	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		1012	everything else.
		1013
		1014	=cut
		1015
		1016	sub aio_rmtree;
		1017	sub aio_rmtree($;$) {
		1018	my ($path, $cb) = @_;
		1019
		1020	my $pri = aioreq_pri;
		1021	my $grp = aio_group $cb;
		1022
		1023	aioreq_pri $pri;
		1024	add $grp aio_scandir $path, 0, sub {
		1025	my ($dirs, $nondirs) = @_;
		1026
		1027	my $dirgrp = aio_group sub {
		1028	add $grp aio_rmdir $path, sub {
		1029	$grp->result ($_[0]);
		1030	};
		1031	};
		1032
		1033	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1034	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1035
		1036	add $grp $dirgrp;
		1037	};
		1038
		1039	$grp
		1040	}
		1041
		1042	=item aio_sync $callback->($status)
		1043
		1044	Asynchronously call sync and call the callback when finished.
		1045
683	=item aio_fsync $fh, $callback->($status)	1046	=item aio_fsync $fh, $callback->($status)
684		1047
685	Asynchronously call fsync on the given filehandle and call the callback	1048	Asynchronously call fsync on the given filehandle and call the callback
686	with the fsync result code.	1049	with the fsync result code.
687		1050
…		…
690	Asynchronously call fdatasync on the given filehandle and call the	1053	Asynchronously call fdatasync on the given filehandle and call the
691	callback with the fdatasync result code.	1054	callback with the fdatasync result code.
692		1055
693	If this call isn't available because your OS lacks it or it couldn't be	1056	If this call isn't available because your OS lacks it or it couldn't be
694	detected, it will be emulated by calling C<fsync> instead.	1057	detected, it will be emulated by calling C<fsync> instead.
		1058
		1059	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1060
		1061	Sync the data portion of the file specified by C<$offset> and C<$length>
		1062	to disk (but NOT the metadata), by calling the Linux-specific
		1063	sync_file_range call. If sync_file_range is not available or it returns
		1064	ENOSYS, then fdatasync or fsync is being substituted.
		1065
		1066	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1067	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1068	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1069	manpage for details.
		1070
		1071	=item aio_pathsync $path, $callback->($status)
		1072
		1073	This request tries to open, fsync and close the given path. This is a
		1074	composite request intended to sync directories after directory operations
		1075	(E.g. rename). This might not work on all operating systems or have any
		1076	specific effect, but usually it makes sure that directory changes get
		1077	written to disc. It works for anything that can be opened for read-only,
		1078	not just directories.
		1079
		1080	Future versions of this function might fall back to other methods when
		1081	C<fsync> on the directory fails (such as calling C<sync>).
		1082
		1083	Passes C<0> when everything went ok, and C<-1> on error.
		1084
		1085	=cut
		1086
		1087	sub aio_pathsync($;$) {
		1088	my ($path, $cb) = @_;
		1089
		1090	my $pri = aioreq_pri;
		1091	my $grp = aio_group $cb;
		1092
		1093	aioreq_pri $pri;
		1094	add $grp aio_open $path, O_RDONLY, 0, sub {
		1095	my ($fh) = @_;
		1096	if ($fh) {
		1097	aioreq_pri $pri;
		1098	add $grp aio_fsync $fh, sub {
		1099	$grp->result ($_[0]);
		1100
		1101	aioreq_pri $pri;
		1102	add $grp aio_close $fh;
		1103	};
		1104	} else {
		1105	$grp->result (-1);
		1106	}
		1107	};
		1108
		1109	$grp
		1110	}
		1111
		1112	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1113
		1114	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1115	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1116	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1117	scalar must only be modified in-place while an aio operation is pending on
		1118	it).
		1119
		1120	It calls the C<msync> function of your OS, if available, with the memory
		1121	area starting at C<$offset> in the string and ending C<$length> bytes
		1122	later. If C<$length> is negative, counts from the end, and if C<$length>
		1123	is C<undef>, then it goes till the end of the string. The flags can be
		1124	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1125	C<IO::AIO::MS_SYNC>.
		1126
		1127	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1128
		1129	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1130	scalars.
		1131
		1132	It touches (reads or writes) all memory pages in the specified
		1133	range inside the scalar. All caveats and parameters are the same
		1134	as for C<aio_msync>, above, except for flags, which must be either
		1135	C<0> (which reads all pages and ensures they are instantiated) or
		1136	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1137	writing an octet from it, which dirties the page).
		1138
		1139	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1140
		1141	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1142	scalars.
		1143
		1144	It reads in all the pages of the underlying storage into memory (if any)
		1145	and locks them, so they are not getting swapped/paged out or removed.
		1146
		1147	If C<$length> is undefined, then the scalar will be locked till the end.
		1148
		1149	On systems that do not implement C<mlock>, this function returns C<-1>
		1150	and sets errno to C<ENOSYS>.
		1151
		1152	Note that the corresponding C<munlock> is synchronous and is
		1153	documented under L<MISCELLANEOUS FUNCTIONS>.
		1154
		1155	Example: open a file, mmap and mlock it - both will be undone when
		1156	C<$data> gets destroyed.
		1157
		1158	open my $fh, "<", $path or die "$path: $!";
		1159	my $data;
		1160	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1161	aio_mlock $data; # mlock in background
		1162
		1163	=item aio_mlockall $flags, $callback->($status)
		1164
		1165	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1166	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1167
		1168	On systems that do not implement C<mlockall>, this function returns C<-1>
		1169	and sets errno to C<ENOSYS>.
		1170
		1171	Note that the corresponding C<munlockall> is synchronous and is
		1172	documented under L<MISCELLANEOUS FUNCTIONS>.
		1173
		1174	Example: asynchronously lock all current and future pages into memory.
		1175
		1176	aio_mlockall IO::AIO::MCL_FUTURE;
695		1177
696	=item aio_group $callback->(...)	1178	=item aio_group $callback->(...)
697		1179
698	This is a very special aio request: Instead of doing something, it is a	1180	This is a very special aio request: Instead of doing something, it is a
699	container for other aio requests, which is useful if you want to bundle	1181	container for other aio requests, which is useful if you want to bundle
…		…
749	=item cancel $req	1231	=item cancel $req
750		1232
751	Cancels the request, if possible. Has the effect of skipping execution	1233	Cancels the request, if possible. Has the effect of skipping execution
752	when entering the B<execute> state and skipping calling the callback when	1234	when entering the B<execute> state and skipping calling the callback when
753	entering the the B<result> state, but will leave the request otherwise	1235	entering the the B<result> state, but will leave the request otherwise
754	untouched. That means that requests that currently execute will not be	1236	untouched (with the exception of readdir). That means that requests that
755	stopped and resources held by the request will not be freed prematurely.	1237	currently execute will not be stopped and resources held by the request
		1238	will not be freed prematurely.
756		1239
757	=item cb $req $callback->(...)	1240	=item cb $req $callback->(...)
758		1241
759	Replace (or simply set) the callback registered to the request.	1242	Replace (or simply set) the callback registered to the request.
760		1243
…		…
811	Their lifetime, simplified, looks like this: when they are empty, they	1294	Their lifetime, simplified, looks like this: when they are empty, they
812	will finish very quickly. If they contain only requests that are in the	1295	will finish very quickly. If they contain only requests that are in the
813	C<done> state, they will also finish. Otherwise they will continue to	1296	C<done> state, they will also finish. Otherwise they will continue to
814	exist.	1297	exist.
815		1298
816	That means after creating a group you have some time to add requests. And	1299	That means after creating a group you have some time to add requests
817	in the callbacks of those requests, you can add further requests to the	1300	(precisely before the callback has been invoked, which is only done within
818	group. And only when all those requests have finished will the the group	1301	the C<poll_cb>). And in the callbacks of those requests, you can add
819	itself finish.	1302	further requests to the group. And only when all those requests have
		1303	finished will the the group itself finish.
820		1304
821	=over 4	1305	=over 4
822		1306
823	=item add $grp ...	1307	=item add $grp ...
824		1308
…		…
833	=item $grp->cancel_subs	1317	=item $grp->cancel_subs
834		1318
835	Cancel all subrequests and clears any feeder, but not the group request	1319	Cancel all subrequests and clears any feeder, but not the group request
836	itself. Useful when you queued a lot of events but got a result early.	1320	itself. Useful when you queued a lot of events but got a result early.
837		1321
		1322	The group request will finish normally (you cannot add requests to the
		1323	group).
		1324
838	=item $grp->result (...)	1325	=item $grp->result (...)
839		1326
840	Set the result value(s) that will be passed to the group callback when all	1327	Set the result value(s) that will be passed to the group callback when all
841	subrequests have finished and set thre groups errno to the current value	1328	subrequests have finished and set the groups errno to the current value
842	of errno (just like calling C<errno> without an error number). By default,	1329	of errno (just like calling C<errno> without an error number). By default,
843	no argument will be passed and errno is zero.	1330	no argument will be passed and errno is zero.
844		1331
845	=item $grp->errno ([$errno])	1332	=item $grp->errno ([$errno])
846		1333
…		…
857	=item feed $grp $callback->($grp)	1344	=item feed $grp $callback->($grp)
858		1345
859	Sets a feeder/generator on this group: every group can have an attached	1346	Sets a feeder/generator on this group: every group can have an attached
860	generator that generates requests if idle. The idea behind this is that,	1347	generator that generates requests if idle. The idea behind this is that,
861	although you could just queue as many requests as you want in a group,	1348	although you could just queue as many requests as you want in a group,
862	this might starve other requests for a potentially long time. For	1349	this might starve other requests for a potentially long time. For example,
863	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1350	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
864	requests, delaying any later requests for a long time.	1351	delaying any later requests for a long time.
865		1352
866	To avoid this, and allow incremental generation of requests, you can	1353	To avoid this, and allow incremental generation of requests, you can
867	instead a group and set a feeder on it that generates those requests. The	1354	instead a group and set a feeder on it that generates those requests. The
868	feed callback will be called whenever there are few enough (see C<limit>,	1355	feed callback will be called whenever there are few enough (see C<limit>,
869	below) requests active in the group itself and is expected to queue more	1356	below) requests active in the group itself and is expected to queue more
…		…
873	not impose any limits).	1360	not impose any limits).
874		1361
875	If the feed does not queue more requests when called, it will be	1362	If the feed does not queue more requests when called, it will be
876	automatically removed from the group.	1363	automatically removed from the group.
877		1364
878	If the feed limit is C<0>, it will be set to C<2> automatically.	1365	If the feed limit is C<0> when this method is called, it will be set to
		1366	C<2> automatically.
879		1367
880	Example:	1368	Example:
881		1369
882	# stat all files in @files, but only ever use four aio requests concurrently:	1370	# stat all files in @files, but only ever use four aio requests concurrently:
883		1371
…		…
895	Sets the feeder limit for the group: The feeder will be called whenever	1383	Sets the feeder limit for the group: The feeder will be called whenever
896	the group contains less than this many requests.	1384	the group contains less than this many requests.
897		1385
898	Setting the limit to C<0> will pause the feeding process.	1386	Setting the limit to C<0> will pause the feeding process.
899		1387
		1388	The default value for the limit is C<0>, but note that setting a feeder
		1389	automatically bumps it up to C<2>.
		1390
900	=back	1391	=back
901		1392
902	=head2 SUPPORT FUNCTIONS	1393	=head2 SUPPORT FUNCTIONS
903		1394
904	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1395	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
906	=over 4	1397	=over 4
907		1398
908	=item $fileno = IO::AIO::poll_fileno	1399	=item $fileno = IO::AIO::poll_fileno
909		1400
910	Return the I<request result pipe file descriptor>. This filehandle must be	1401	Return the I<request result pipe file descriptor>. This filehandle must be
911	polled for reading by some mechanism outside this module (e.g. Event or	1402	polled for reading by some mechanism outside this module (e.g. EV, Glib,
912	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1403	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
913	to call C<poll_cb> to check the results.	1404	you have to call C<poll_cb> to check the results.
914		1405
915	See C<poll_cb> for an example.	1406	See C<poll_cb> for an example.
916		1407
917	=item IO::AIO::poll_cb	1408	=item IO::AIO::poll_cb
918		1409
919	Process some outstanding events on the result pipe. You have to call this	1410	Process some outstanding events on the result pipe. You have to call this
920	regularly. Returns the number of events processed. Returns immediately	1411	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1412	returned earlier for whatever reason. Returns immediately when no events
921	when no events are outstanding. The amount of events processed depends on	1413	are outstanding. The amount of events processed depends on the settings of
922	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1414	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
923		1415
924	If not all requests were processed for whatever reason, the filehandle	1416	If not all requests were processed for whatever reason, the filehandle
925	will still be ready when C<poll_cb> returns.	1417	will still be ready when C<poll_cb> returns, so normally you don't have to
		1418	do anything special to have it called later.
926		1419
927	Example: Install an Event watcher that automatically calls	1420	Example: Install an Event watcher that automatically calls
928	IO::AIO::poll_cb with high priority:	1421	IO::AIO::poll_cb with high priority (more examples can be found in the
		1422	SYNOPSIS section, at the top of this document):
929		1423
930	Event->io (fd => IO::AIO::poll_fileno,	1424	Event->io (fd => IO::AIO::poll_fileno,
931	poll => 'r', async => 1,	1425	poll => 'r', async => 1,
932	cb => \&IO::AIO::poll_cb);	1426	cb => \&IO::AIO::poll_cb);
		1427
		1428	=item IO::AIO::poll_wait
		1429
		1430	If there are any outstanding requests and none of them in the result
		1431	phase, wait till the result filehandle becomes ready for reading (simply
		1432	does a C<select> on the filehandle. This is useful if you want to
		1433	synchronously wait for some requests to finish).
		1434
		1435	See C<nreqs> for an example.
		1436
		1437	=item IO::AIO::poll
		1438
		1439	Waits until some requests have been handled.
		1440
		1441	Returns the number of requests processed, but is otherwise strictly
		1442	equivalent to:
		1443
		1444	IO::AIO::poll_wait, IO::AIO::poll_cb
		1445
		1446	=item IO::AIO::flush
		1447
		1448	Wait till all outstanding AIO requests have been handled.
		1449
		1450	Strictly equivalent to:
		1451
		1452	IO::AIO::poll_wait, IO::AIO::poll_cb
		1453	while IO::AIO::nreqs;
933		1454
934	=item IO::AIO::max_poll_reqs $nreqs	1455	=item IO::AIO::max_poll_reqs $nreqs
935		1456
936	=item IO::AIO::max_poll_time $seconds	1457	=item IO::AIO::max_poll_time $seconds
937		1458
…		…
939	that are being processed by C<IO::AIO::poll_cb> in one call, respectively	1460	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
940	the maximum amount of time (default C<0>, meaning infinity) spent in	1461	the maximum amount of time (default C<0>, meaning infinity) spent in
941	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount	1462	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
942	of time C<poll_cb> is allowed to use).	1463	of time C<poll_cb> is allowed to use).
943		1464
		1465	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1466	syscall per request processed, which is not normally a problem unless your
		1467	callbacks are really really fast or your OS is really really slow (I am
		1468	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1469
944	Setting these is useful if you want to ensure some level of	1470	Setting these is useful if you want to ensure some level of
945	interactiveness when perl is not fast enough to process all requests in	1471	interactiveness when perl is not fast enough to process all requests in
946	time.	1472	time.
947		1473
948	For interactive programs, values such as C<0.01> to C<0.1> should be fine.	1474	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
949		1475
950	Example: Install an Event watcher that automatically calls	1476	Example: Install an Event watcher that automatically calls
951	IO::AIO::poll_some with low priority, to ensure that other parts of the	1477	IO::AIO::poll_cb with low priority, to ensure that other parts of the
952	program get the CPU sometimes even under high AIO load.	1478	program get the CPU sometimes even under high AIO load.
953		1479
954	# try not to spend much more than 0.1s in poll_cb	1480	# try not to spend much more than 0.1s in poll_cb
955	IO::AIO::max_poll_time 0.1;	1481	IO::AIO::max_poll_time 0.1;
956		1482
957	# use a low priority so other tasks have priority	1483	# use a low priority so other tasks have priority
958	Event->io (fd => IO::AIO::poll_fileno,	1484	Event->io (fd => IO::AIO::poll_fileno,
959	poll => 'r', nice => 1,	1485	poll => 'r', nice => 1,
960	cb => &IO::AIO::poll_cb);	1486	cb => &IO::AIO::poll_cb);
961		1487
962	=item IO::AIO::poll_wait	1488	=back
963
964	Wait till the result filehandle becomes ready for reading (simply does a
965	C<select> on the filehandle. This is useful if you want to synchronously
966	wait for some requests to finish).
967
968	See C<nreqs> for an example.
969
970	=item IO::AIO::poll
971
972	Waits until some requests have been handled.
973
974	Strictly equivalent to:
975
976	IO::AIO::poll_wait, IO::AIO::poll_cb
977	if IO::AIO::nreqs;
978
979	=item IO::AIO::flush
980
981	Wait till all outstanding AIO requests have been handled.
982
983	Strictly equivalent to:
984
985	IO::AIO::poll_wait, IO::AIO::poll_cb
986	while IO::AIO::nreqs;
987		1489
988	=head3 CONTROLLING THE NUMBER OF THREADS	1490	=head3 CONTROLLING THE NUMBER OF THREADS
		1491
		1492	=over
989		1493
990	=item IO::AIO::min_parallel $nthreads	1494	=item IO::AIO::min_parallel $nthreads
991		1495
992	Set the minimum number of AIO threads to C<$nthreads>. The current	1496	Set the minimum number of AIO threads to C<$nthreads>. The current
993	default is C<8>, which means eight asynchronous operations can execute	1497	default is C<8>, which means eight asynchronous operations can execute
…		…
1034		1538
1035	The default is probably ok in most situations, especially if thread	1539	The default is probably ok in most situations, especially if thread
1036	creation is fast. If thread creation is very slow on your system you might	1540	creation is fast. If thread creation is very slow on your system you might
1037	want to use larger values.	1541	want to use larger values.
1038		1542
1039	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1543	=item IO::AIO::max_outstanding $maxreqs
1040		1544
1041	This is a very bad function to use in interactive programs because it	1545	This is a very bad function to use in interactive programs because it
1042	blocks, and a bad way to reduce concurrency because it is inexact: Better	1546	blocks, and a bad way to reduce concurrency because it is inexact: Better
1043	use an C<aio_group> together with a feed callback.	1547	use an C<aio_group> together with a feed callback.
1044		1548
1045	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1549	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1046	to queue up more than this number of requests, the next call to the	1550	do queue up more than this number of requests, the next call to the
1047	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1551	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1048	function will block until the limit is no longer exceeded.	1552	function will block until the limit is no longer exceeded.
1049		1553
1050	The default value is very large, so there is no practical limit on the	1554	The default value is very large, so there is no practical limit on the
1051	number of outstanding requests.	1555	number of outstanding requests.
1052		1556
1053	You can still queue as many requests as you want. Therefore,	1557	You can still queue as many requests as you want. Therefore,
1054	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1558	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1055	as a stop gap to shield against fatal memory overflow (with large values).	1559	as a stop gap to shield against fatal memory overflow (with large values).
1056		1560
		1561	=back
		1562
1057	=head3 STATISTICAL INFORMATION	1563	=head3 STATISTICAL INFORMATION
		1564
		1565	=over
1058		1566
1059	=item IO::AIO::nreqs	1567	=item IO::AIO::nreqs
1060		1568
1061	Returns the number of requests currently in the ready, execute or pending	1569	Returns the number of requests currently in the ready, execute or pending
1062	states (i.e. for which their callback has not been invoked yet).	1570	states (i.e. for which their callback has not been invoked yet).
…		…
1076	Returns the number of requests currently in the pending state (executed,	1584	Returns the number of requests currently in the pending state (executed,
1077	but not yet processed by poll_cb).	1585	but not yet processed by poll_cb).
1078		1586
1079	=back	1587	=back
1080		1588
		1589	=head3 MISCELLANEOUS FUNCTIONS
		1590
		1591	IO::AIO implements some functions that might be useful, but are not
		1592	asynchronous.
		1593
		1594	=over 4
		1595
		1596	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1597
		1598	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1599	but is blocking (this makes most sense if you know the input data is
		1600	likely cached already and the output filehandle is set to non-blocking
		1601	operations).
		1602
		1603	Returns the number of bytes copied, or C<-1> on error.
		1604
		1605	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1606
		1607	Simply calls the C<posix_fadvise> function (see its
		1608	manpage for details). The following advice constants are
		1609	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1610	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1611	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1612
		1613	On systems that do not implement C<posix_fadvise>, this function returns
		1614	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1615
		1616	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1617
		1618	Simply calls the C<posix_madvise> function (see its
		1619	manpage for details). The following advice constants are
		1620	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1621	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1622
		1623	On systems that do not implement C<posix_madvise>, this function returns
		1624	ENOSYS, otherwise the return value of C<posix_madvise>.
		1625
		1626	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1627
		1628	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1629	$scalar (see its manpage for details). The following protect
		1630	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1631	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1632
		1633	On systems that do not implement C<mprotect>, this function returns
		1634	ENOSYS, otherwise the return value of C<mprotect>.
		1635
		1636	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1637
		1638	Memory-maps a file (or anonymous memory range) and attaches it to the
		1639	given C<$scalar>, which will act like a string scalar.
		1640
		1641	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1642	change the string length, and most read-only operations such as copying it
		1643	or searching it with regexes and so on.
		1644
		1645	Anything else is unsafe and will, at best, result in memory leaks.
		1646
		1647	The memory map associated with the C<$scalar> is automatically removed
		1648	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1649	C<IO::AIO::munmap> functions are called.
		1650
		1651	This calls the C<mmap>(2) function internally. See your system's manual
		1652	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1653
		1654	The C<$length> must be larger than zero and smaller than the actual
		1655	filesize.
		1656
		1657	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1658	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1659
		1660	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1661	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1662	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1663	(which is set to C<MAP_ANON> if your system only provides this
		1664	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1665	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1666	C<IO::AIO::MAP_NONBLOCK>
		1667
		1668	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1669
		1670	C<$offset> is the offset from the start of the file - it generally must be
		1671	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1672
		1673	Example:
		1674
		1675	use Digest::MD5;
		1676	use IO::AIO;
		1677
		1678	open my $fh, "<verybigfile"
		1679	or die "$!";
		1680
		1681	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1682	or die "verybigfile: $!";
		1683
		1684	my $fast_md5 = md5 $data;
		1685
		1686	=item IO::AIO::munmap $scalar
		1687
		1688	Removes a previous mmap and undefines the C<$scalar>.
		1689
		1690	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1691
		1692	Calls the C<munlock> function, undoing the effects of a previous
		1693	C<aio_mlock> call (see its description for details).
		1694
		1695	=item IO::AIO::munlockall
		1696
		1697	Calls the C<munlockall> function.
		1698
		1699	On systems that do not implement C<munlockall>, this function returns
		1700	ENOSYS, otherwise the return value of C<munlockall>.
		1701
		1702	=back
		1703
1081	=cut	1704	=cut
1082		1705
1083	# support function to convert a fd into a perl filehandle
1084	sub _fd2fh {
1085	return undef if $_[0] < 0;
1086
1087	# try to generate nice filehandles
1088	my $sym = "IO::AIO::fd#$_[0]";
1089	local *$sym;
1090
1091	open *$sym, "+<&=$_[0]" # usually works under any unix
1092	or open *$sym, "<&=$_[0]" # cygwin needs this
1093	or open *$sym, ">&=$_[0]" # or this
1094	or return undef;
1095
1096	*$sym
1097	}
1098
1099	min_parallel 8;	1706	min_parallel 8;
1100		1707
1101	END {	1708	END { flush }
1102	min_parallel 1;
1103	flush;
1104	};
1105		1709
1106	1;	1710	1;
		1711
		1712	=head1 EVENT LOOP INTEGRATION
		1713
		1714	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1715	automatically into many event loops:
		1716
		1717	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1718	use AnyEvent::AIO;
		1719
		1720	You can also integrate IO::AIO manually into many event loops, here are
		1721	some examples of how to do this:
		1722
		1723	# EV integration
		1724	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1725
		1726	# Event integration
		1727	Event->io (fd => IO::AIO::poll_fileno,
		1728	poll => 'r',
		1729	cb => \&IO::AIO::poll_cb);
		1730
		1731	# Glib/Gtk2 integration
		1732	add_watch Glib::IO IO::AIO::poll_fileno,
		1733	in => sub { IO::AIO::poll_cb; 1 };
		1734
		1735	# Tk integration
		1736	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1737	readable => \&IO::AIO::poll_cb);
		1738
		1739	# Danga::Socket integration
		1740	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1741	\&IO::AIO::poll_cb);
1107		1742
1108	=head2 FORK BEHAVIOUR	1743	=head2 FORK BEHAVIOUR
1109		1744
1110	This module should do "the right thing" when the process using it forks:	1745	This module should do "the right thing" when the process using it forks:
1111		1746
…		…
1129	bytes of memory. In addition, stat requests need a stat buffer (possibly	1764	bytes of memory. In addition, stat requests need a stat buffer (possibly
1130	a few hundred bytes), readdir requires a result buffer and so on. Perl	1765	a few hundred bytes), readdir requires a result buffer and so on. Perl
1131	scalars and other data passed into aio requests will also be locked and	1766	scalars and other data passed into aio requests will also be locked and
1132	will consume memory till the request has entered the done state.	1767	will consume memory till the request has entered the done state.
1133		1768
1134	This is now awfully much, so queuing lots of requests is not usually a	1769	This is not awfully much, so queuing lots of requests is not usually a
1135	problem.	1770	problem.
1136		1771
1137	Per-thread usage:	1772	Per-thread usage:
1138		1773
1139	In the execution phase, some aio requests require more memory for	1774	In the execution phase, some aio requests require more memory for
…		…
1144		1779
1145	Known bugs will be fixed in the next release.	1780	Known bugs will be fixed in the next release.
1146		1781
1147	=head1 SEE ALSO	1782	=head1 SEE ALSO
1148		1783
1149	L<Coro::AIO>.	1784	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1785	more natural syntax.
1150		1786
1151	=head1 AUTHOR	1787	=head1 AUTHOR
1152		1788
1153	Marc Lehmann <schmorp@schmorp.de>	1789	Marc Lehmann <schmorp@schmorp.de>
1154	http://home.schmorp.de/	1790	http://home.schmorp.de/

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