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Revision 1.81 by root, Fri Oct 27 19:17:23 2006 UTC vs.
Revision 1.184 by root, Mon Nov 1 22:03:43 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) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
30	# AnyEvent integration
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33
34	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',
37	cb => \&IO::AIO::poll_cb);
38
39	# Glib/Gtk2 integration
40	add_watch Glib::IO IO::AIO::poll_fileno,
41	in => sub { IO::AIO::poll_cb; 1 };
42
43	# Tk integration
44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
45	readable => \&IO::AIO::poll_cb);
46
47	# Danga::Socket integration
48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
49	\&IO::AIO::poll_cb);
50
51	=head1 DESCRIPTION	31	=head1 DESCRIPTION
52		32
53	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
54	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
		36
		37	Asynchronous means that operations that can normally block your program
		38	(e.g. reading from disk) will be done asynchronously: the operation
		39	will still block, but you can do something else in the meantime. This
		40	is extremely useful for programs that need to stay interactive even
		41	when doing heavy I/O (GUI programs, high performance network servers
		42	etc.), but can also be used to easily do operations in parallel that are
		43	normally done sequentially, e.g. stat'ing many files, which is much faster
		44	on a RAID volume or over NFS when you do a number of stat operations
		45	concurrently.
		46
		47	While most of this works on all types of file descriptors (for
		48	example sockets), using these functions on file descriptors that
		49	support nonblocking operation (again, sockets, pipes etc.) is
		50	very inefficient. Use an event loop for that (such as the L<EV>
		51	module): IO::AIO will naturally fit into such an event loop itself.
55		52
56	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
57	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
58	in perl, and the threads created by this module will not be visible	55	in perl, and the threads created by this module will not be visible
59	to perl. In the future, this module might make use of the native aio	56	to perl. In the future, this module might make use of the native aio
60	functions available on many operating systems. However, they are often	57	functions available on many operating systems. However, they are often
61	not well-supported or restricted (Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
63	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
64	using threads anyway.	61	using threads anyway.
65		62
66	Although the module will work with in the presence of other (Perl-)	63	Although the module will work in the presence of other (Perl-) threads,
67	threads, it is currently not reentrant in any way, so use appropriate	64	it is currently not reentrant in any way, so use appropriate locking
68	locking yourself, always call C<poll_cb> from within the same thread, or	65	yourself, always call C<poll_cb> from within the same thread, or never
69	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
		67
		68	=head2 EXAMPLE
		69
		70	This is a simple example that uses the EV module and loads
		71	F</etc/passwd> asynchronously:
		72
		73	use Fcntl;
		74	use EV;
		75	use IO::AIO;
		76
		77	# register the IO::AIO callback with EV
		78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		79
		80	# queue the request to open /etc/passwd
		81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
		82	my $fh = shift
		83	or die "error while opening: $!";
		84
		85	# stat'ing filehandles is generally non-blocking
		86	my $size = -s $fh;
		87
		88	# queue a request to read the file
		89	my $contents;
		90	aio_read $fh, 0, $size, $contents, 0, sub {
		91	$_[0] == $size
		92	or die "short read: $!";
		93
		94	close $fh;
		95
		96	# file contents now in $contents
		97	print $contents;
		98
		99	# exit event loop and program
		100	EV::unloop;
		101	};
		102	};
		103
		104	# possibly queue up other requests, or open GUI windows,
		105	# check for sockets etc. etc.
		106
		107	# process events as long as there are some:
		108	EV::loop;
70		109
71	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
72		111
73	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
74	directly visible to Perl.	113	directly visible to Perl.
…		…
116	Request has reached the end of its lifetime and holds no resources anymore	155	Request has reached the end of its lifetime and holds no resources anymore
117	(except possibly for the Perl object, but its connection to the actual	156	(except possibly for the Perl object, but its connection to the actual
118	aio request is severed and calling its methods will either do nothing or	157	aio request is severed and calling its methods will either do nothing or
119	result in a runtime error).	158	result in a runtime error).
120		159
		160	=back
		161
121	=cut	162	=cut
122		163
123	package IO::AIO;	164	package IO::AIO;
124		165
125	no warnings;	166	use Carp ();
126	use strict 'vars';	167
		168	use common::sense;
127		169
128	use base 'Exporter';	170	use base 'Exporter';
129		171
130	BEGIN {	172	BEGIN {
131	our $VERSION = '2.0';	173	our $VERSION = '3.7';
132		174
133	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
134	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
		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
136	aio_group aio_nop);	183	aio_statvfs);
		184
137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139	min_parallel max_parallel nreqs nready npending);	187	min_parallel max_parallel max_idle
		188	nreqs nready npending nthreads
		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
140		194
141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142		196
143	require XSLoader;	197	require XSLoader;
144	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
145	}	199	}
146		200
147	=head1 FUNCTIONS	201	=head1 FUNCTIONS
148		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, $length = undef
		273	IO::AIO::munlockall
		274
149	=head2 AIO FUNCTIONS	275	=head2 AIO REQUEST FUNCTIONS
150		276
151	All the C<aio_*> calls are more or less thin wrappers around the syscall	277	All the C<aio_*> calls are more or less thin wrappers around the syscall
152	with the same name (sans C<aio_>). The arguments are similar or identical,	278	with the same name (sans C<aio_>). The arguments are similar or identical,
153	and they all accept an additional (and optional) C<$callback> argument	279	and they all accept an additional (and optional) C<$callback> argument
154	which must be a code reference. This code reference will get called with	280	which must be a code reference. This code reference will get called with
155	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	281	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
156	perl, which usually delivers "false") as it's sole argument when the given	282	perl, which usually delivers "false") as its sole argument after the given
157	syscall has been executed asynchronously.	283	syscall has been executed asynchronously.
158		284
159	All functions expecting a filehandle keep a copy of the filehandle	285	All functions expecting a filehandle keep a copy of the filehandle
160	internally until the request has finished.	286	internally until the request has finished.
161		287
162	All requests return objects of type L<IO::AIO::REQ> that allow further	288	All functions return request objects of type L<IO::AIO::REQ> that allow
163	manipulation of those requests while they are in-flight.	289	further manipulation of those requests while they are in-flight.
164		290
165	The pathnames you pass to these routines I<must> be absolute and	291	The pathnames you pass to these routines I<must> be absolute and
166	encoded in byte form. The reason for the former is that at the time the	292	encoded as octets. The reason for the former is that at the time the
167	request is being executed, the current working directory could have	293	request is being executed, the current working directory could have
168	changed. Alternatively, you can make sure that you never change the	294	changed. Alternatively, you can make sure that you never change the
169	current working directory.	295	current working directory anywhere in the program and then use relative
		296	paths.
170		297
171	To encode pathnames to byte form, either make sure you either: a)	298	To encode pathnames as octets, either make sure you either: a) always pass
172	always pass in filenames you got from outside (command line, readdir	299	in filenames you got from outside (command line, readdir etc.) without
173	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	300	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174	your pathnames to the locale (or other) encoding in effect in the user	301	your pathnames to the locale (or other) encoding in effect in the user
175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	302	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176	use something else.	303	use something else to ensure your scalar has the correct contents.
		304
		305	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		306	handles correctly whether it is set or not.
177		307
178	=over 4	308	=over 4
179		309
180	=item $prev_pri = aioreq_pri [$pri]	310	=item $prev_pri = aioreq_pri [$pri]
181		311
…		…
201	aio_read $_[0], ..., sub {	331	aio_read $_[0], ..., sub {
202	...	332	...
203	};	333	};
204	};	334	};
205		335
		336
206	=item aioreq_nice $pri_adjust	337	=item aioreq_nice $pri_adjust
207		338
208	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
209	priority, so effects are cumulative.	340	priority, so the effect is cumulative.
		341
210		342
211	=item aio_open $pathname, $flags, $mode, $callback->($fh)	343	=item aio_open $pathname, $flags, $mode, $callback->($fh)
212		344
213	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
214	created filehandle for the file.	346	created filehandle for the file.
…		…
220	list. They are the same as used by C<sysopen>.	352	list. They are the same as used by C<sysopen>.
221		353
222	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
223	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>,
224	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,
225	and C<0666> or C<0777> if you do).	357	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		358	by the umask in effect then the request is being executed, so better never
		359	change the umask.
226		360
227	Example:	361	Example:
228		362
229	aio_open "/etc/passwd", O_RDONLY, 0, sub {	363	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
230	if ($_[0]) {	364	if ($_[0]) {
231	print "open successful, fh is $_[0]\n";	365	print "open successful, fh is $_[0]\n";
232	...	366	...
233	} else {	367	} else {
234	die "open failed: $!\n";	368	die "open failed: $!\n";
235	}	369	}
236	};	370	};
237		371
		372
238	=item aio_close $fh, $callback->($status)	373	=item aio_close $fh, $callback->($status)
239		374
240	Asynchronously close a file and call the callback with the result	375	Asynchronously close a file and call the callback with the result
241	code. I<WARNING:> although accepted, you should not pass in a perl	376	code.
242	filehandle here, as perl will likely close the file descriptor another
243	time when the filehandle is destroyed. Normally, you can safely call perls
244	C<close> or just let filehandles go out of scope.
245		377
246	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
247	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
248		389
249	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	390	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250		391
251	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	392	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252		393
253	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
254	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<$dataoffset>
255	callback without the actual number of bytes read (or -1 on error, just	396	and calls the callback without the actual number of bytes read (or -1 on
256	like the syscall).	397	error, just like the syscall).
		398
		399	C<aio_read> will, like C<sysread>, shrink or grow the C<$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<$data>.
257		411
258	The C<$data> scalar I<MUST NOT> be modified in any way while the request	412	The C<$data> scalar I<MUST NOT> be modified in any way while the request
259	is outstanding. Modifying it can result in segfaults or WW3 (if the	413	is outstanding. Modifying it can result in segfaults or World War III (if
260	necessary/optional hardware is installed).	414	the necessary/optional hardware is installed).
261		415
262	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	416	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263	offset C<0> within the scalar:	417	offset C<0> within the scalar:
264		418
265	aio_read $fh, 7, 15, $buffer, 0, sub {	419	aio_read $fh, 7, 15, $buffer, 0, sub {
266	$_[0] > 0 or die "read error: $!";	420	$_[0] > 0 or die "read error: $!";
267	print "read $_[0] bytes: <$buffer>\n";	421	print "read $_[0] bytes: <$buffer>\n";
268	};	422	};
269		423
270	=item aio_move $srcpath, $dstpath, $callback->($status)
271
272	Try to move the I<file> (directories not supported as either source or
273	destination) from C<$srcpath> to C<$dstpath> and call the callback with
274	the C<0> (error) or C<-1> ok.
275
276	This is a composite request that tries to rename(2) the file first. If
277	rename files with C<EXDEV>, it creates the destination file with mode 0200
278	and copies the contents of the source file into it using C<aio_sendfile>,
279	followed by restoring atime, mtime, access mode and uid/gid, in that
280	order, and unlinking the C<$srcpath>.
281
282	If an error occurs, the partial destination file will be unlinked, if
283	possible, except when setting atime, mtime, access mode and uid/gid, where
284	errors are being ignored.
285
286	=cut
287
288	sub aio_move($$$) {
289	my ($src, $dst, $cb) = @_;
290
291	my $pri = aioreq_pri;
292	my $grp = aio_group $cb;
293
294	aioreq_pri $pri;
295	add $grp aio_rename $src, $dst, sub {
296	if ($_[0] && $! == EXDEV) {
297	aioreq_pri $pri;
298	add $grp aio_open $src, O_RDONLY, 0, sub {
299	if (my $src_fh = $_[0]) {
300	my @stat = stat $src_fh;
301
302	aioreq_pri $pri;
303	add $grp aio_open $dst, O_WRONLY, 0200, sub {
304	if (my $dst_fh = $_[0]) {
305	aioreq_pri $pri;
306	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
307	close $src_fh;
308
309	if ($_[0] == $stat[7]) {
310	utime $stat[8], $stat[9], $dst;
311	chmod $stat[2] & 07777, $dst_fh;
312	chown $stat[4], $stat[5], $dst_fh;
313	close $dst_fh;
314
315	aioreq_pri $pri;
316	add $grp aio_unlink $src, sub {
317	$grp->result ($_[0]);
318	};
319	} else {
320	my $errno = $!;
321	aioreq_pri $pri;
322	add $grp aio_unlink $dst, sub {
323	$! = $errno;
324	$grp->result (-1);
325	};
326	}
327	};
328	} else {
329	$grp->result (-1);
330	}
331	},
332
333	} else {
334	$grp->result (-1);
335	}
336	};
337	} else {
338	$grp->result ($_[0]);
339	}
340	};
341
342	$grp
343	}
344		424
345	=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)
346		426
347	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
348	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
…		…
350	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
351	other.	431	other.
352		432
353	This call tries to make use of a native C<sendfile> syscall to provide	433	This call tries to make use of a native C<sendfile> syscall to provide
354	zero-copy operation. For this to work, C<$out_fh> should refer to a	434	zero-copy operation. For this to work, C<$out_fh> should refer to a
355	socket, and C<$in_fh> should refer to mmap'able file.	435	socket, and C<$in_fh> should refer to an mmap'able file.
356		436
357	If the native sendfile call fails or is not implemented, it will be	437	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		438	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
358	emulated, so you can call C<aio_sendfile> on any type of filehandle	439	it will be emulated, so you can call C<aio_sendfile> on any type of
359	regardless of the limitations of the operating system.	440	filehandle regardless of the limitations of the operating system.
360		441
361	Please note, however, that C<aio_sendfile> can read more bytes from	442	Please note, however, that C<aio_sendfile> can read more bytes from
362	C<$in_fh> than are written, and there is no way to find out how many	443	C<$in_fh> than are written, and there is no way to find out how many
363	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	444	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
364	provides the number of bytes written to C<$out_fh>. Only if the result	445	provides the number of bytes written to C<$out_fh>. Only if the result
365	value equals C<$length> one can assume that C<$length> bytes have been	446	value equals C<$length> one can assume that C<$length> bytes have been
366	read.	447	read.
		448
367		449
368	=item aio_readahead $fh,$offset,$length, $callback->($retval)	450	=item aio_readahead $fh,$offset,$length, $callback->($retval)
369		451
370	C<aio_readahead> populates the page cache with data from a file so that	452	C<aio_readahead> populates the page cache with data from a file so that
371	subsequent reads from that file will not block on disk I/O. The C<$offset>	453	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
377	file. The current file offset of the file is left unchanged.	459	file. The current file offset of the file is left unchanged.
378		460
379	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	461	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
380	emulated by simply reading the data, which would have a similar effect.	462	emulated by simply reading the data, which would have a similar effect.
381		463
		464
382	=item aio_stat $fh_or_path, $callback->($status)	465	=item aio_stat $fh_or_path, $callback->($status)
383		466
384	=item aio_lstat $fh, $callback->($status)	467	=item aio_lstat $fh, $callback->($status)
385		468
386	Works like perl's C<stat> or C<lstat> in void context. The callback will	469	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
399	aio_stat "/etc/passwd", sub {	482	aio_stat "/etc/passwd", sub {
400	$_[0] and die "stat failed: $!";	483	$_[0] and die "stat failed: $!";
401	print "size is ", -s _, "\n";	484	print "size is ", -s _, "\n";
402	};	485	};
403		486
		487
		488	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		489
		490	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		491	whether a file handle or path was passed.
		492
		493	On success, the callback is passed a hash reference with the following
		494	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		495	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		496	is passed.
		497
		498	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		499	C<ST_NOSUID>.
		500
		501	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		502	their correct value when available, or to C<0> on systems that do
		503	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		504	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		505	C<ST_NODIRATIME> and C<ST_RELATIME>.
		506
		507	Example: stat C</wd> and dump out the data if successful.
		508
		509	aio_statvfs "/wd", sub {
		510	my $f = $_[0]
		511	or die "statvfs: $!";
		512
		513	use Data::Dumper;
		514	say Dumper $f;
		515	};
		516
		517	# result:
		518	{
		519	bsize => 1024,
		520	bfree => 4333064312,
		521	blocks => 10253828096,
		522	files => 2050765568,
		523	flag => 4096,
		524	favail => 2042092649,
		525	bavail => 4333064312,
		526	ffree => 2042092649,
		527	namemax => 255,
		528	frsize => 1024,
		529	fsid => 1810
		530	}
		531
		532
		533	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		534
		535	Works like perl's C<utime> function (including the special case of $atime
		536	and $mtime being undef). Fractional times are supported if the underlying
		537	syscalls support them.
		538
		539	When called with a pathname, uses utimes(2) if available, otherwise
		540	utime(2). If called on a file descriptor, uses futimes(2) if available,
		541	otherwise returns ENOSYS, so this is not portable.
		542
		543	Examples:
		544
		545	# set atime and mtime to current time (basically touch(1)):
		546	aio_utime "path", undef, undef;
		547	# set atime to current time and mtime to beginning of the epoch:
		548	aio_utime "path", time, undef; # undef==0
		549
		550
		551	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		552
		553	Works like perl's C<chown> function, except that C<undef> for either $uid
		554	or $gid is being interpreted as "do not change" (but -1 can also be used).
		555
		556	Examples:
		557
		558	# same as "chown root path" in the shell:
		559	aio_chown "path", 0, -1;
		560	# same as above:
		561	aio_chown "path", 0, undef;
		562
		563
		564	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		565
		566	Works like truncate(2) or ftruncate(2).
		567
		568
		569	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		570
		571	Works like perl's C<chmod> function.
		572
		573
404	=item aio_unlink $pathname, $callback->($status)	574	=item aio_unlink $pathname, $callback->($status)
405		575
406	Asynchronously unlink (delete) a file and call the callback with the	576	Asynchronously unlink (delete) a file and call the callback with the
407	result code.	577	result code.
408		578
		579
		580	=item aio_mknod $path, $mode, $dev, $callback->($status)
		581
		582	[EXPERIMENTAL]
		583
		584	Asynchronously create a device node (or fifo). See mknod(2).
		585
		586	The only (POSIX-) portable way of calling this function is:
		587
		588	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		589
		590
409	=item aio_link $srcpath, $dstpath, $callback->($status)	591	=item aio_link $srcpath, $dstpath, $callback->($status)
410		592
411	Asynchronously create a new link to the existing object at C<$srcpath> at	593	Asynchronously create a new link to the existing object at C<$srcpath> at
412	the path C<$dstpath> and call the callback with the result code.	594	the path C<$dstpath> and call the callback with the result code.
413		595
		596
414	=item aio_symlink $srcpath, $dstpath, $callback->($status)	597	=item aio_symlink $srcpath, $dstpath, $callback->($status)
415		598
416	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	599	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
417	the path C<$dstpath> and call the callback with the result code.	600	the path C<$dstpath> and call the callback with the result code.
418		601
		602
		603	=item aio_readlink $path, $callback->($link)
		604
		605	Asynchronously read the symlink specified by C<$path> and pass it to
		606	the callback. If an error occurs, nothing or undef gets passed to the
		607	callback.
		608
		609
419	=item aio_rename $srcpath, $dstpath, $callback->($status)	610	=item aio_rename $srcpath, $dstpath, $callback->($status)
420		611
421	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	612	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
422	rename(2) and call the callback with the result code.	613	rename(2) and call the callback with the result code.
423		614
		615
		616	=item aio_mkdir $pathname, $mode, $callback->($status)
		617
		618	Asynchronously mkdir (create) a directory and call the callback with
		619	the result code. C<$mode> will be modified by the umask at the time the
		620	request is executed, so do not change your umask.
		621
		622
424	=item aio_rmdir $pathname, $callback->($status)	623	=item aio_rmdir $pathname, $callback->($status)
425		624
426	Asynchronously rmdir (delete) a directory and call the callback with the	625	Asynchronously rmdir (delete) a directory and call the callback with the
427	result code.	626	result code.
		627
428		628
429	=item aio_readdir $pathname, $callback->($entries)	629	=item aio_readdir $pathname, $callback->($entries)
430		630
431	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	631	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
432	directory (i.e. opendir + readdir + closedir). The entries will not be	632	directory (i.e. opendir + readdir + closedir). The entries will not be
433	sorted, and will B<NOT> include the C<.> and C<..> entries.	633	sorted, and will B<NOT> include the C<.> and C<..> entries.
434		634
435	The callback a single argument which is either C<undef> or an array-ref	635	The callback is passed a single argument which is either C<undef> or an
436	with the filenames.	636	array-ref with the filenames.
		637
		638
		639	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		640
		641	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		642	behaviour and output format. In case of an error, C<$entries> will be
		643	C<undef>.
		644
		645	The flags are a combination of the following constants, ORed together (the
		646	flags will also be passed to the callback, possibly modified):
		647
		648	=over 4
		649
		650	=item IO::AIO::READDIR_DENTS
		651
		652	When this flag is off, then the callback gets an arrayref with of names
		653	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		654	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		655	entry in more detail.
		656
		657	C<$name> is the name of the entry.
		658
		659	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		660
		661	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		662	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		663	C<IO::AIO::DT_WHT>.
		664
		665	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		666	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		667	scalars are read-only: you can not modify them.
		668
		669	C<$inode> is the inode number (which might not be exact on systems with 64
		670	bit inode numbers and 32 bit perls). This field has unspecified content on
		671	systems that do not deliver the inode information.
		672
		673	=item IO::AIO::READDIR_DIRS_FIRST
		674
		675	When this flag is set, then the names will be returned in an order where
		676	likely directories come first. This is useful when you need to quickly
		677	find directories, or you want to find all directories while avoiding to
		678	stat() each entry.
		679
		680	If the system returns type information in readdir, then this is used
		681	to find directories directly. Otherwise, likely directories are files
		682	beginning with ".", or otherwise files with no dots, of which files with
		683	short names are tried first.
		684
		685	=item IO::AIO::READDIR_STAT_ORDER
		686
		687	When this flag is set, then the names will be returned in an order
		688	suitable for stat()'ing each one. That is, when you plan to stat()
		689	all files in the given directory, then the returned order will likely
		690	be fastest.
		691
		692	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		693	the likely dirs come first, resulting in a less optimal stat order.
		694
		695	=item IO::AIO::READDIR_FOUND_UNKNOWN
		696
		697	This flag should not be set when calling C<aio_readdirx>. Instead, it
		698	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		699	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		700	C<$type>'s are known, which can be used to speed up some algorithms.
		701
		702	=back
		703
		704
		705	=item aio_load $path, $data, $callback->($status)
		706
		707	This is a composite request that tries to fully load the given file into
		708	memory. Status is the same as with aio_read.
		709
		710	=cut
		711
		712	sub aio_load($$;$) {
		713	my ($path, undef, $cb) = @_;
		714	my $data = \$_[1];
		715
		716	my $pri = aioreq_pri;
		717	my $grp = aio_group $cb;
		718
		719	aioreq_pri $pri;
		720	add $grp aio_open $path, O_RDONLY, 0, sub {
		721	my $fh = shift
		722	or return $grp->result (-1);
		723
		724	aioreq_pri $pri;
		725	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		726	$grp->result ($_[0]);
		727	};
		728	};
		729
		730	$grp
		731	}
		732
		733	=item aio_copy $srcpath, $dstpath, $callback->($status)
		734
		735	Try to copy the I<file> (directories not supported as either source or
		736	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		737	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		738
		739	This is a composite request that creates the destination file with
		740	mode 0200 and copies the contents of the source file into it using
		741	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		742	uid/gid, in that order.
		743
		744	If an error occurs, the partial destination file will be unlinked, if
		745	possible, except when setting atime, mtime, access mode and uid/gid, where
		746	errors are being ignored.
		747
		748	=cut
		749
		750	sub aio_copy($$;$) {
		751	my ($src, $dst, $cb) = @_;
		752
		753	my $pri = aioreq_pri;
		754	my $grp = aio_group $cb;
		755
		756	aioreq_pri $pri;
		757	add $grp aio_open $src, O_RDONLY, 0, sub {
		758	if (my $src_fh = $_[0]) {
		759	my @stat = stat $src_fh; # hmm, might block over nfs?
		760
		761	aioreq_pri $pri;
		762	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
		763	if (my $dst_fh = $_[0]) {
		764	aioreq_pri $pri;
		765	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		766	if ($_[0] == $stat[7]) {
		767	$grp->result (0);
		768	close $src_fh;
		769
		770	my $ch = sub {
		771	aioreq_pri $pri;
		772	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		773	aioreq_pri $pri;
		774	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		775	aioreq_pri $pri;
		776	add $grp aio_close $dst_fh;
		777	}
		778	};
		779	};
		780
		781	aioreq_pri $pri;
		782	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		783	if ($_[0] < 0 && $! == ENOSYS) {
		784	aioreq_pri $pri;
		785	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		786	} else {
		787	$ch->();
		788	}
		789	};
		790	} else {
		791	$grp->result (-1);
		792	close $src_fh;
		793	close $dst_fh;
		794
		795	aioreq $pri;
		796	add $grp aio_unlink $dst;
		797	}
		798	};
		799	} else {
		800	$grp->result (-1);
		801	}
		802	},
		803
		804	} else {
		805	$grp->result (-1);
		806	}
		807	};
		808
		809	$grp
		810	}
		811
		812	=item aio_move $srcpath, $dstpath, $callback->($status)
		813
		814	Try to move the I<file> (directories not supported as either source or
		815	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		816	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		817
		818	This is a composite request that tries to rename(2) the file first; if
		819	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
		820	that is successful, unlinks the C<$srcpath>.
		821
		822	=cut
		823
		824	sub aio_move($$;$) {
		825	my ($src, $dst, $cb) = @_;
		826
		827	my $pri = aioreq_pri;
		828	my $grp = aio_group $cb;
		829
		830	aioreq_pri $pri;
		831	add $grp aio_rename $src, $dst, sub {
		832	if ($_[0] && $! == EXDEV) {
		833	aioreq_pri $pri;
		834	add $grp aio_copy $src, $dst, sub {
		835	$grp->result ($_[0]);
		836
		837	if (!$_[0]) {
		838	aioreq_pri $pri;
		839	add $grp aio_unlink $src;
		840	}
		841	};
		842	} else {
		843	$grp->result ($_[0]);
		844	}
		845	};
		846
		847	$grp
		848	}
437		849
438	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	850	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
439		851
440	Scans a directory (similar to C<aio_readdir>) but additionally tries to	852	Scans a directory (similar to C<aio_readdir>) but additionally tries to
441	efficiently separate the entries of directory C<$path> into two sets of	853	efficiently separate the entries of directory C<$path> into two sets of
…		…
460		872
461	Implementation notes.	873	Implementation notes.
462		874
463	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	875	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
464		876
		877	If readdir returns file type information, then this is used directly to
		878	find directories.
		879
465	After reading the directory, the modification time, size etc. of the	880	Otherwise, after reading the directory, the modification time, size etc.
466	directory before and after the readdir is checked, and if they match (and	881	of the directory before and after the readdir is checked, and if they
467	isn't the current time), the link count will be used to decide how many	882	match (and isn't the current time), the link count will be used to decide
468	entries are directories (if >= 2). Otherwise, no knowledge of the number	883	how many entries are directories (if >= 2). Otherwise, no knowledge of the
469	of subdirectories will be assumed.	884	number of subdirectories will be assumed.
470		885
471	Then entries will be sorted into likely directories (everything without	886	Then entries will be sorted into likely directories a non-initial dot
472	a non-initial dot currently) and likely non-directories (everything	887	currently) and likely non-directories (see C<aio_readdirx>). Then every
473	else). Then every entry plus an appended C</.> will be C<stat>'ed,	888	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
474	likely directories first. If that succeeds, it assumes that the entry	889	in order of their inode numbers. If that succeeds, it assumes that the
475	is a directory or a symlink to directory (which will be checked	890	entry is a directory or a symlink to directory (which will be checked
476	seperately). This is often faster than stat'ing the entry itself because	891	seperately). This is often faster than stat'ing the entry itself because
477	filesystems might detect the type of the entry without reading the inode	892	filesystems might detect the type of the entry without reading the inode
478	data (e.g. ext2fs filetype feature).	893	data (e.g. ext2fs filetype feature), even on systems that cannot return
		894	the filetype information on readdir.
479		895
480	If the known number of directories (link count - 2) has been reached, the	896	If the known number of directories (link count - 2) has been reached, the
481	rest of the entries is assumed to be non-directories.	897	rest of the entries is assumed to be non-directories.
482		898
483	This only works with certainty on POSIX (= UNIX) filesystems, which	899	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
487	as those tend to return 0 or 1 as link counts, which disables the	903	as those tend to return 0 or 1 as link counts, which disables the
488	directory counting heuristic.	904	directory counting heuristic.
489		905
490	=cut	906	=cut
491		907
492	sub aio_scandir($$$) {	908	sub aio_scandir($$;$) {
493	my ($path, $maxreq, $cb) = @_;	909	my ($path, $maxreq, $cb) = @_;
494		910
495	my $pri = aioreq_pri;	911	my $pri = aioreq_pri;
496		912
497	my $grp = aio_group $cb;	913	my $grp = aio_group $cb;
…		…
505	my $now = time;	921	my $now = time;
506	my $hash1 = join ":", (stat _)[0,1,3,7,9];	922	my $hash1 = join ":", (stat _)[0,1,3,7,9];
507		923
508	# read the directory entries	924	# read the directory entries
509	aioreq_pri $pri;	925	aioreq_pri $pri;
510	add $grp aio_readdir $path, sub {	926	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
511	my $entries = shift	927	my $entries = shift
512	or return $grp->result ();	928	or return $grp->result ();
513		929
514	# stat the dir another time	930	# stat the dir another time
515	aioreq_pri $pri;	931	aioreq_pri $pri;
…		…
521	# take the slow route if anything looks fishy	937	# take the slow route if anything looks fishy
522	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	938	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
523	$ndirs = -1;	939	$ndirs = -1;
524	} else {	940	} else {
525	# if nlink == 2, we are finished	941	# if nlink == 2, we are finished
526	# on non-posix-fs's, we rely on nlink < 2	942	# for non-posix-fs's, we rely on nlink < 2
527	$ndirs = (stat _)[3] - 2	943	$ndirs = (stat _)[3] - 2
528	or return $grp->result ([], $entries);	944	or return $grp->result ([], $entries);
529	}	945	}
530		946
531	# sort into likely dirs and likely nondirs
532	# dirs == files without ".", short entries first
533	$entries = [map $_->[0],
534	sort { $b->[1] cmp $a->[1] }
535	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
536	@$entries];
537
538	my (@dirs, @nondirs);	947	my (@dirs, @nondirs);
539		948
540	my $statgrp = add $grp aio_group sub {	949	my $statgrp = add $grp aio_group sub {
541	$grp->result (\@dirs, \@nondirs);	950	$grp->result (\@dirs, \@nondirs);
542	};	951	};
543		952
544	limit $statgrp $maxreq;	953	limit $statgrp $maxreq;
545	feed $statgrp sub {	954	feed $statgrp sub {
546	return unless @$entries;	955	return unless @$entries;
547	my $entry = pop @$entries;	956	my $entry = shift @$entries;
548		957
549	aioreq_pri $pri;	958	aioreq_pri $pri;
550	add $statgrp aio_stat "$path/$entry/.", sub {	959	add $statgrp aio_stat "$path/$entry/.", sub {
551	if ($_[0] < 0) {	960	if ($_[0] < 0) {
552	push @nondirs, $entry;	961	push @nondirs, $entry;
…		…
573	};	982	};
574		983
575	$grp	984	$grp
576	}	985	}
577		986
		987	=item aio_rmtree $path, $callback->($status)
		988
		989	Delete a directory tree starting (and including) C<$path>, return the
		990	status of the final C<rmdir> only. This is a composite request that
		991	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		992	everything else.
		993
		994	=cut
		995
		996	sub aio_rmtree;
		997	sub aio_rmtree($;$) {
		998	my ($path, $cb) = @_;
		999
		1000	my $pri = aioreq_pri;
		1001	my $grp = aio_group $cb;
		1002
		1003	aioreq_pri $pri;
		1004	add $grp aio_scandir $path, 0, sub {
		1005	my ($dirs, $nondirs) = @_;
		1006
		1007	my $dirgrp = aio_group sub {
		1008	add $grp aio_rmdir $path, sub {
		1009	$grp->result ($_[0]);
		1010	};
		1011	};
		1012
		1013	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1014	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1015
		1016	add $grp $dirgrp;
		1017	};
		1018
		1019	$grp
		1020	}
		1021
		1022	=item aio_sync $callback->($status)
		1023
		1024	Asynchronously call sync and call the callback when finished.
		1025
578	=item aio_fsync $fh, $callback->($status)	1026	=item aio_fsync $fh, $callback->($status)
579		1027
580	Asynchronously call fsync on the given filehandle and call the callback	1028	Asynchronously call fsync on the given filehandle and call the callback
581	with the fsync result code.	1029	with the fsync result code.
582		1030
…		…
585	Asynchronously call fdatasync on the given filehandle and call the	1033	Asynchronously call fdatasync on the given filehandle and call the
586	callback with the fdatasync result code.	1034	callback with the fdatasync result code.
587		1035
588	If this call isn't available because your OS lacks it or it couldn't be	1036	If this call isn't available because your OS lacks it or it couldn't be
589	detected, it will be emulated by calling C<fsync> instead.	1037	detected, it will be emulated by calling C<fsync> instead.
		1038
		1039	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1040
		1041	Sync the data portion of the file specified by C<$offset> and C<$length>
		1042	to disk (but NOT the metadata), by calling the Linux-specific
		1043	sync_file_range call. If sync_file_range is not available or it returns
		1044	ENOSYS, then fdatasync or fsync is being substituted.
		1045
		1046	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1047	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1048	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1049	manpage for details.
		1050
		1051	=item aio_pathsync $path, $callback->($status)
		1052
		1053	This request tries to open, fsync and close the given path. This is a
		1054	composite request intended to sync directories after directory operations
		1055	(E.g. rename). This might not work on all operating systems or have any
		1056	specific effect, but usually it makes sure that directory changes get
		1057	written to disc. It works for anything that can be opened for read-only,
		1058	not just directories.
		1059
		1060	Future versions of this function might fall back to other methods when
		1061	C<fsync> on the directory fails (such as calling C<sync>).
		1062
		1063	Passes C<0> when everything went ok, and C<-1> on error.
		1064
		1065	=cut
		1066
		1067	sub aio_pathsync($;$) {
		1068	my ($path, $cb) = @_;
		1069
		1070	my $pri = aioreq_pri;
		1071	my $grp = aio_group $cb;
		1072
		1073	aioreq_pri $pri;
		1074	add $grp aio_open $path, O_RDONLY, 0, sub {
		1075	my ($fh) = @_;
		1076	if ($fh) {
		1077	aioreq_pri $pri;
		1078	add $grp aio_fsync $fh, sub {
		1079	$grp->result ($_[0]);
		1080
		1081	aioreq_pri $pri;
		1082	add $grp aio_close $fh;
		1083	};
		1084	} else {
		1085	$grp->result (-1);
		1086	}
		1087	};
		1088
		1089	$grp
		1090	}
		1091
		1092	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1093
		1094	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1095	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1096	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1097	scalar must only be modified in-place while an aio operation is pending on
		1098	it).
		1099
		1100	It calls the C<msync> function of your OS, if available, with the memory
		1101	area starting at C<$offset> in the string and ending C<$length> bytes
		1102	later. If C<$length> is negative, counts from the end, and if C<$length>
		1103	is C<undef>, then it goes till the end of the string. The flags can be
		1104	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1105	C<IO::AIO::MS_SYNC>.
		1106
		1107	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1108
		1109	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1110	scalars.
		1111
		1112	It touches (reads or writes) all memory pages in the specified
		1113	range inside the scalar. All caveats and parameters are the same
		1114	as for C<aio_msync>, above, except for flags, which must be either
		1115	C<0> (which reads all pages and ensures they are instantiated) or
		1116	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1117	writing an octet from it, which dirties the page).
		1118
		1119	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1120
		1121	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1122	scalars.
		1123
		1124	It reads in all the pages of the underlying storage into memory (if any)
		1125	and locks them, so they are not getting swapped/paged out or removed.
		1126
		1127	If C<$length> is undefined, then the scalar will be locked till the end.
		1128
		1129	On systems that do not implement C<mlock>, this function returns C<-1>
		1130	and sets errno to C<ENOSYS>.
		1131
		1132	Note that the corresponding C<munlock> is synchronous and is
		1133	documented under L<MISCELLANEOUS FUNCTIONS>.
		1134
		1135	Example: open a file, mmap and mlock it - both will be undone when
		1136	C<$data> gets destroyed.
		1137
		1138	open my $fh, "<", $path or die "$path: $!";
		1139	my $data;
		1140	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1141	aio_mlock $data; # mlock in background
		1142
		1143	=item aio_mlockall $flags, $callback->($status)
		1144
		1145	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1146	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1147
		1148	On systems that do not implement C<mlockall>, this function returns C<-1>
		1149	and sets errno to C<ENOSYS>.
		1150
		1151	Note that the corresponding C<munlockall> is synchronous and is
		1152	documented under L<MISCELLANEOUS FUNCTIONS>.
		1153
		1154	Example: asynchronously lock all current and future pages into memory.
		1155
		1156	aio_mlockall IO::AIO::MCL_FUTURE;
590		1157
591	=item aio_group $callback->(...)	1158	=item aio_group $callback->(...)
592		1159
593	This is a very special aio request: Instead of doing something, it is a	1160	This is a very special aio request: Instead of doing something, it is a
594	container for other aio requests, which is useful if you want to bundle	1161	container for other aio requests, which is useful if you want to bundle
…		…
644	=item cancel $req	1211	=item cancel $req
645		1212
646	Cancels the request, if possible. Has the effect of skipping execution	1213	Cancels the request, if possible. Has the effect of skipping execution
647	when entering the B<execute> state and skipping calling the callback when	1214	when entering the B<execute> state and skipping calling the callback when
648	entering the the B<result> state, but will leave the request otherwise	1215	entering the the B<result> state, but will leave the request otherwise
649	untouched. That means that requests that currently execute will not be	1216	untouched (with the exception of readdir). That means that requests that
650	stopped and resources held by the request will not be freed prematurely.	1217	currently execute will not be stopped and resources held by the request
		1218	will not be freed prematurely.
651		1219
652	=item cb $req $callback->(...)	1220	=item cb $req $callback->(...)
653		1221
654	Replace (or simply set) the callback registered to the request.	1222	Replace (or simply set) the callback registered to the request.
655		1223
…		…
706	Their lifetime, simplified, looks like this: when they are empty, they	1274	Their lifetime, simplified, looks like this: when they are empty, they
707	will finish very quickly. If they contain only requests that are in the	1275	will finish very quickly. If they contain only requests that are in the
708	C<done> state, they will also finish. Otherwise they will continue to	1276	C<done> state, they will also finish. Otherwise they will continue to
709	exist.	1277	exist.
710		1278
711	That means after creating a group you have some time to add requests. And	1279	That means after creating a group you have some time to add requests
712	in the callbacks of those requests, you can add further requests to the	1280	(precisely before the callback has been invoked, which is only done within
713	group. And only when all those requests have finished will the the group	1281	the C<poll_cb>). And in the callbacks of those requests, you can add
714	itself finish.	1282	further requests to the group. And only when all those requests have
		1283	finished will the the group itself finish.
715		1284
716	=over 4	1285	=over 4
717		1286
718	=item add $grp ...	1287	=item add $grp ...
719		1288
…		…
728	=item $grp->cancel_subs	1297	=item $grp->cancel_subs
729		1298
730	Cancel all subrequests and clears any feeder, but not the group request	1299	Cancel all subrequests and clears any feeder, but not the group request
731	itself. Useful when you queued a lot of events but got a result early.	1300	itself. Useful when you queued a lot of events but got a result early.
732		1301
		1302	The group request will finish normally (you cannot add requests to the
		1303	group).
		1304
733	=item $grp->result (...)	1305	=item $grp->result (...)
734		1306
735	Set the result value(s) that will be passed to the group callback when all	1307	Set the result value(s) that will be passed to the group callback when all
736	subrequests have finished and set thre groups errno to the current value	1308	subrequests have finished and set the groups errno to the current value
737	of errno (just like calling C<errno> without an error number). By default,	1309	of errno (just like calling C<errno> without an error number). By default,
738	no argument will be passed and errno is zero.	1310	no argument will be passed and errno is zero.
739		1311
740	=item $grp->errno ([$errno])	1312	=item $grp->errno ([$errno])
741		1313
…		…
752	=item feed $grp $callback->($grp)	1324	=item feed $grp $callback->($grp)
753		1325
754	Sets a feeder/generator on this group: every group can have an attached	1326	Sets a feeder/generator on this group: every group can have an attached
755	generator that generates requests if idle. The idea behind this is that,	1327	generator that generates requests if idle. The idea behind this is that,
756	although you could just queue as many requests as you want in a group,	1328	although you could just queue as many requests as you want in a group,
757	this might starve other requests for a potentially long time. For	1329	this might starve other requests for a potentially long time. For example,
758	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1330	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
759	requests, delaying any later requests for a long time.	1331	delaying any later requests for a long time.
760		1332
761	To avoid this, and allow incremental generation of requests, you can	1333	To avoid this, and allow incremental generation of requests, you can
762	instead a group and set a feeder on it that generates those requests. The	1334	instead a group and set a feeder on it that generates those requests. The
763	feed callback will be called whenever there are few enough (see C<limit>,	1335	feed callback will be called whenever there are few enough (see C<limit>,
764	below) requests active in the group itself and is expected to queue more	1336	below) requests active in the group itself and is expected to queue more
…		…
768	not impose any limits).	1340	not impose any limits).
769		1341
770	If the feed does not queue more requests when called, it will be	1342	If the feed does not queue more requests when called, it will be
771	automatically removed from the group.	1343	automatically removed from the group.
772		1344
773	If the feed limit is C<0>, it will be set to C<2> automatically.	1345	If the feed limit is C<0> when this method is called, it will be set to
		1346	C<2> automatically.
774		1347
775	Example:	1348	Example:
776		1349
777	# stat all files in @files, but only ever use four aio requests concurrently:	1350	# stat all files in @files, but only ever use four aio requests concurrently:
778		1351
…		…
790	Sets the feeder limit for the group: The feeder will be called whenever	1363	Sets the feeder limit for the group: The feeder will be called whenever
791	the group contains less than this many requests.	1364	the group contains less than this many requests.
792		1365
793	Setting the limit to C<0> will pause the feeding process.	1366	Setting the limit to C<0> will pause the feeding process.
794		1367
		1368	The default value for the limit is C<0>, but note that setting a feeder
		1369	automatically bumps it up to C<2>.
		1370
795	=back	1371	=back
796		1372
797	=head2 SUPPORT FUNCTIONS	1373	=head2 SUPPORT FUNCTIONS
798		1374
		1375	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		1376
799	=over 4	1377	=over 4
800		1378
801	=item $fileno = IO::AIO::poll_fileno	1379	=item $fileno = IO::AIO::poll_fileno
802		1380
803	Return the I<request result pipe file descriptor>. This filehandle must be	1381	Return the I<request result pipe file descriptor>. This filehandle must be
804	polled for reading by some mechanism outside this module (e.g. Event or	1382	polled for reading by some mechanism outside this module (e.g. EV, Glib,
805	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1383	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
806	to call C<poll_cb> to check the results.	1384	you have to call C<poll_cb> to check the results.
807		1385
808	See C<poll_cb> for an example.	1386	See C<poll_cb> for an example.
809		1387
810	=item IO::AIO::poll_cb	1388	=item IO::AIO::poll_cb
811		1389
812	Process all outstanding events on the result pipe. You have to call this	1390	Process some outstanding events on the result pipe. You have to call this
813	regularly. Returns the number of events processed. Returns immediately	1391	regularly. Returns C<0> if all events could be processed, or C<-1> if it
814	when no events are outstanding.	1392	returned earlier for whatever reason. Returns immediately when no events
		1393	are outstanding. The amount of events processed depends on the settings of
		1394	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
815		1395
816	If not all requests were processed for whatever reason, the filehandle	1396	If not all requests were processed for whatever reason, the filehandle
817	will still be ready when C<poll_cb> returns.	1397	will still be ready when C<poll_cb> returns, so normally you don't have to
		1398	do anything special to have it called later.
818		1399
819	Example: Install an Event watcher that automatically calls	1400	Example: Install an Event watcher that automatically calls
820	IO::AIO::poll_cb with high priority:	1401	IO::AIO::poll_cb with high priority (more examples can be found in the
		1402	SYNOPSIS section, at the top of this document):
821		1403
822	Event->io (fd => IO::AIO::poll_fileno,	1404	Event->io (fd => IO::AIO::poll_fileno,
823	poll => 'r', async => 1,	1405	poll => 'r', async => 1,
824	cb => \&IO::AIO::poll_cb);	1406	cb => \&IO::AIO::poll_cb);
825		1407
826	=item IO::AIO::poll_some $max_requests	1408	=item IO::AIO::poll_wait
827		1409
828	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests	1410	If there are any outstanding requests and none of them in the result
829	at a time.	1411	phase, wait till the result filehandle becomes ready for reading (simply
		1412	does a C<select> on the filehandle. This is useful if you want to
		1413	synchronously wait for some requests to finish).
830		1414
831	Useful if you want to ensure some level of interactiveness when perl is	1415	See C<nreqs> for an example.
832	not fast enough to process all requests in time.	1416
		1417	=item IO::AIO::poll
		1418
		1419	Waits until some requests have been handled.
		1420
		1421	Returns the number of requests processed, but is otherwise strictly
		1422	equivalent to:
		1423
		1424	IO::AIO::poll_wait, IO::AIO::poll_cb
		1425
		1426	=item IO::AIO::flush
		1427
		1428	Wait till all outstanding AIO requests have been handled.
		1429
		1430	Strictly equivalent to:
		1431
		1432	IO::AIO::poll_wait, IO::AIO::poll_cb
		1433	while IO::AIO::nreqs;
		1434
		1435	=item IO::AIO::max_poll_reqs $nreqs
		1436
		1437	=item IO::AIO::max_poll_time $seconds
		1438
		1439	These set the maximum number of requests (default C<0>, meaning infinity)
		1440	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1441	the maximum amount of time (default C<0>, meaning infinity) spent in
		1442	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1443	of time C<poll_cb> is allowed to use).
		1444
		1445	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1446	syscall per request processed, which is not normally a problem unless your
		1447	callbacks are really really fast or your OS is really really slow (I am
		1448	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1449
		1450	Setting these is useful if you want to ensure some level of
		1451	interactiveness when perl is not fast enough to process all requests in
		1452	time.
		1453
		1454	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
833		1455
834	Example: Install an Event watcher that automatically calls	1456	Example: Install an Event watcher that automatically calls
835	IO::AIO::poll_some with low priority, to ensure that other parts of the	1457	IO::AIO::poll_cb with low priority, to ensure that other parts of the
836	program get the CPU sometimes even under high AIO load.	1458	program get the CPU sometimes even under high AIO load.
837		1459
		1460	# try not to spend much more than 0.1s in poll_cb
		1461	IO::AIO::max_poll_time 0.1;
		1462
		1463	# use a low priority so other tasks have priority
838	Event->io (fd => IO::AIO::poll_fileno,	1464	Event->io (fd => IO::AIO::poll_fileno,
839	poll => 'r', nice => 1,	1465	poll => 'r', nice => 1,
840	cb => sub { IO::AIO::poll_some 256 });	1466	cb => &IO::AIO::poll_cb);
841		1467
842	=item IO::AIO::poll_wait	1468	=back
843		1469
844	Wait till the result filehandle becomes ready for reading (simply does a	1470	=head3 CONTROLLING THE NUMBER OF THREADS
845	C<select> on the filehandle. This is useful if you want to synchronously wait
846	for some requests to finish).
847		1471
848	See C<nreqs> for an example.	1472	=over
849
850	=item IO::AIO::nreqs
851
852	Returns the number of requests currently in the ready, execute or pending
853	states (i.e. for which their callback has not been invoked yet).
854
855	Example: wait till there are no outstanding requests anymore:
856
857	IO::AIO::poll_wait, IO::AIO::poll_cb
858	while IO::AIO::nreqs;
859
860	=item IO::AIO::nready
861
862	Returns the number of requests currently in the ready state (not yet
863	executed).
864
865	=item IO::AIO::npending
866
867	Returns the number of requests currently in the pending state (executed,
868	but not yet processed by poll_cb).
869
870	=item IO::AIO::flush
871
872	Wait till all outstanding AIO requests have been handled.
873
874	Strictly equivalent to:
875
876	IO::AIO::poll_wait, IO::AIO::poll_cb
877	while IO::AIO::nreqs;
878
879	=item IO::AIO::poll
880
881	Waits until some requests have been handled.
882
883	Strictly equivalent to:
884
885	IO::AIO::poll_wait, IO::AIO::poll_cb
886	if IO::AIO::nreqs;
887		1473
888	=item IO::AIO::min_parallel $nthreads	1474	=item IO::AIO::min_parallel $nthreads
889		1475
890	Set the minimum number of AIO threads to C<$nthreads>. The current	1476	Set the minimum number of AIO threads to C<$nthreads>. The current
891	default is C<8>, which means eight asynchronous operations can execute	1477	default is C<8>, which means eight asynchronous operations can execute
892	concurrently at any one time (the number of outstanding requests,	1478	concurrently at any one time (the number of outstanding requests,
893	however, is unlimited).	1479	however, is unlimited).
894		1480
895	IO::AIO starts threads only on demand, when an AIO request is queued and	1481	IO::AIO starts threads only on demand, when an AIO request is queued and
896	no free thread exists.	1482	no free thread exists. Please note that queueing up a hundred requests can
		1483	create demand for a hundred threads, even if it turns out that everything
		1484	is in the cache and could have been processed faster by a single thread.
897		1485
898	It is recommended to keep the number of threads relatively low, as some	1486	It is recommended to keep the number of threads relatively low, as some
899	Linux kernel versions will scale negatively with the number of threads	1487	Linux kernel versions will scale negatively with the number of threads
900	(higher parallelity => MUCH higher latency). With current Linux 2.6	1488	(higher parallelity => MUCH higher latency). With current Linux 2.6
901	versions, 4-32 threads should be fine.	1489	versions, 4-32 threads should be fine.
…		…
915	This module automatically runs C<max_parallel 0> at program end, to ensure	1503	This module automatically runs C<max_parallel 0> at program end, to ensure
916	that all threads are killed and that there are no outstanding requests.	1504	that all threads are killed and that there are no outstanding requests.
917		1505
918	Under normal circumstances you don't need to call this function.	1506	Under normal circumstances you don't need to call this function.
919		1507
		1508	=item IO::AIO::max_idle $nthreads
		1509
		1510	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1511	threads that did not get a request to process within 10 seconds). That
		1512	means if a thread becomes idle while C<$nthreads> other threads are also
		1513	idle, it will free its resources and exit.
		1514
		1515	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1516	to allow for extremely high load situations, but want to free resources
		1517	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1518
		1519	The default is probably ok in most situations, especially if thread
		1520	creation is fast. If thread creation is very slow on your system you might
		1521	want to use larger values.
		1522
920	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1523	=item IO::AIO::max_outstanding $maxreqs
921		1524
922	This is a very bad function to use in interactive programs because it	1525	This is a very bad function to use in interactive programs because it
923	blocks, and a bad way to reduce concurrency because it is inexact: Better	1526	blocks, and a bad way to reduce concurrency because it is inexact: Better
924	use an C<aio_group> together with a feed callback.	1527	use an C<aio_group> together with a feed callback.
925		1528
926	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1529	Sets the maximum number of outstanding requests to C<$nreqs>. If you
927	to queue up more than this number of requests, the next call to the	1530	do queue up more than this number of requests, the next call to the
928	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1531	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
929	function will block until the limit is no longer exceeded.	1532	function will block until the limit is no longer exceeded.
930		1533
931	The default value is very large, so there is no practical limit on the	1534	The default value is very large, so there is no practical limit on the
932	number of outstanding requests.	1535	number of outstanding requests.
933		1536
934	You can still queue as many requests as you want. Therefore,	1537	You can still queue as many requests as you want. Therefore,
935	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1538	C<max_outstanding> is mainly useful in simple scripts (with low values) or
936	as a stop gap to shield against fatal memory overflow (with large values).	1539	as a stop gap to shield against fatal memory overflow (with large values).
937		1540
938	=back	1541	=back
939		1542
		1543	=head3 STATISTICAL INFORMATION
		1544
		1545	=over
		1546
		1547	=item IO::AIO::nreqs
		1548
		1549	Returns the number of requests currently in the ready, execute or pending
		1550	states (i.e. for which their callback has not been invoked yet).
		1551
		1552	Example: wait till there are no outstanding requests anymore:
		1553
		1554	IO::AIO::poll_wait, IO::AIO::poll_cb
		1555	while IO::AIO::nreqs;
		1556
		1557	=item IO::AIO::nready
		1558
		1559	Returns the number of requests currently in the ready state (not yet
		1560	executed).
		1561
		1562	=item IO::AIO::npending
		1563
		1564	Returns the number of requests currently in the pending state (executed,
		1565	but not yet processed by poll_cb).
		1566
		1567	=back
		1568
		1569	=head3 MISCELLANEOUS FUNCTIONS
		1570
		1571	IO::AIO implements some functions that might be useful, but are not
		1572	asynchronous.
		1573
		1574	=over 4
		1575
		1576	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1577
		1578	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1579	but is blocking (this makes most sense if you know the input data is
		1580	likely cached already and the output filehandle is set to non-blocking
		1581	operations).
		1582
		1583	Returns the number of bytes copied, or C<-1> on error.
		1584
		1585	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1586
		1587	Simply calls the C<posix_fadvise> function (see its
		1588	manpage for details). The following advice constants are
		1589	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1590	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1591	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1592
		1593	On systems that do not implement C<posix_fadvise>, this function returns
		1594	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1595
		1596	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1597
		1598	Simply calls the C<posix_madvise> function (see its
		1599	manpage for details). The following advice constants are
		1600	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1601	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1602
		1603	On systems that do not implement C<posix_madvise>, this function returns
		1604	ENOSYS, otherwise the return value of C<posix_madvise>.
		1605
		1606	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1607
		1608	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1609	$scalar (see its manpage for details). The following protect
		1610	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1611	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1612
		1613	On systems that do not implement C<mprotect>, this function returns
		1614	ENOSYS, otherwise the return value of C<mprotect>.
		1615
		1616	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1617
		1618	Memory-maps a file (or anonymous memory range) and attaches it to the
		1619	given C<$scalar>, which will act like a string scalar.
		1620
		1621	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1622	change the string length, and most read-only operations such as copying it
		1623	or searching it with regexes and so on.
		1624
		1625	Anything else is unsafe and will, at best, result in memory leaks.
		1626
		1627	The memory map associated with the C<$scalar> is automatically removed
		1628	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1629	C<IO::AIO::munmap> functions are called.
		1630
		1631	This calls the C<mmap>(2) function internally. See your system's manual
		1632	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1633
		1634	The C<$length> must be larger than zero and smaller than the actual
		1635	filesize.
		1636
		1637	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1638	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1639
		1640	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1641	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1642	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1643	(which is set to C<MAP_ANON> if your system only provides this
		1644	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1645	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1646	C<IO::AIO::MAP_NONBLOCK>
		1647
		1648	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1649
		1650	C<$offset> is the offset from the start of the file - it generally must be
		1651	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1652
		1653	Example:
		1654
		1655	use Digest::MD5;
		1656	use IO::AIO;
		1657
		1658	open my $fh, "<verybigfile"
		1659	or die "$!";
		1660
		1661	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1662	or die "verybigfile: $!";
		1663
		1664	my $fast_md5 = md5 $data;
		1665
		1666	=item IO::AIO::munmap $scalar
		1667
		1668	Removes a previous mmap and undefines the C<$scalar>.
		1669
		1670	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1671
		1672	Calls the C<munlock> function, undoing the effects of a previous
		1673	C<aio_mlock> call (see its description for details).
		1674
		1675	=item IO::AIO::munlockall
		1676
		1677	Calls the C<munlockall> function.
		1678
		1679	On systems that do not implement C<munlockall>, this function returns
		1680	ENOSYS, otherwise the return value of C<munlockall>.
		1681
		1682	=back
		1683
940	=cut	1684	=cut
941		1685
942	# support function to convert a fd into a perl filehandle
943	sub _fd2fh {
944	return undef if $_[0] < 0;
945
946	# try to generate nice filehandles
947	my $sym = "IO::AIO::fd#$_[0]";
948	local *$sym;
949
950	open *$sym, "+<&=$_[0]" # usually works under any unix
951	or open *$sym, "<&=$_[0]" # cygwin needs this
952	or open *$sym, ">&=$_[0]" # or this
953	or return undef;
954
955	*$sym
956	}
957
958	min_parallel 8;	1686	min_parallel 8;
959		1687
		1688	END { flush }
		1689
960	1;	1690	1;
		1691
		1692	=head1 EVENT LOOP INTEGRATION
		1693
		1694	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1695	automatically into many event loops:
		1696
		1697	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1698	use AnyEvent::AIO;
		1699
		1700	You can also integrate IO::AIO manually into many event loops, here are
		1701	some examples of how to do this:
		1702
		1703	# EV integration
		1704	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1705
		1706	# Event integration
		1707	Event->io (fd => IO::AIO::poll_fileno,
		1708	poll => 'r',
		1709	cb => \&IO::AIO::poll_cb);
		1710
		1711	# Glib/Gtk2 integration
		1712	add_watch Glib::IO IO::AIO::poll_fileno,
		1713	in => sub { IO::AIO::poll_cb; 1 };
		1714
		1715	# Tk integration
		1716	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1717	readable => \&IO::AIO::poll_cb);
		1718
		1719	# Danga::Socket integration
		1720	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1721	\&IO::AIO::poll_cb);
961		1722
962	=head2 FORK BEHAVIOUR	1723	=head2 FORK BEHAVIOUR
963		1724
964	This module should do "the right thing" when the process using it forks:	1725	This module should do "the right thing" when the process using it forks:
965		1726
…		…
983	bytes of memory. In addition, stat requests need a stat buffer (possibly	1744	bytes of memory. In addition, stat requests need a stat buffer (possibly
984	a few hundred bytes), readdir requires a result buffer and so on. Perl	1745	a few hundred bytes), readdir requires a result buffer and so on. Perl
985	scalars and other data passed into aio requests will also be locked and	1746	scalars and other data passed into aio requests will also be locked and
986	will consume memory till the request has entered the done state.	1747	will consume memory till the request has entered the done state.
987		1748
988	This is now awfully much, so queuing lots of requests is not usually a	1749	This is not awfully much, so queuing lots of requests is not usually a
989	problem.	1750	problem.
990		1751
991	Per-thread usage:	1752	Per-thread usage:
992		1753
993	In the execution phase, some aio requests require more memory for	1754	In the execution phase, some aio requests require more memory for
…		…
998		1759
999	Known bugs will be fixed in the next release.	1760	Known bugs will be fixed in the next release.
1000		1761
1001	=head1 SEE ALSO	1762	=head1 SEE ALSO
1002		1763
1003	L<Coro::AIO>.	1764	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1765	more natural syntax.
1004		1766
1005	=head1 AUTHOR	1767	=head1 AUTHOR
1006		1768
1007	Marc Lehmann <schmorp@schmorp.de>	1769	Marc Lehmann <schmorp@schmorp.de>
1008	http://home.schmorp.de/	1770	http://home.schmorp.de/

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