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Revision 1.119 by root, Sun Dec 2 20:54:33 2007 UTC vs.
Revision 1.189 by root, Sun Mar 27 10:26:08 2011 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration (EV, Event, Glib, Tk, urxvt, pureperl...)
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35	# EV integration
36	my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
37
38	# Event integration
39	Event->io (fd => IO::AIO::poll_fileno,
40	poll => 'r',
41	cb => \&IO::AIO::poll_cb);
42
43	# Glib/Gtk2 integration
44	add_watch Glib::IO IO::AIO::poll_fileno,
45	in => sub { IO::AIO::poll_cb; 1 };
46
47	# Tk integration
48	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
49	readable => \&IO::AIO::poll_cb);
50
51	# Danga::Socket integration
52	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
53	\&IO::AIO::poll_cb);
54
55	=head1 DESCRIPTION	31	=head1 DESCRIPTION
56		32
57	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
58	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>).
59		36
60	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
61	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
62	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
63	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
67	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
68	concurrently.	45	concurrently.
69		46
70	While most of this works on all types of file descriptors (for	47	While most of this works on all types of file descriptors (for
71	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
72	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
73	inefficient. Use an event loop for that (such as the L<Event|Event>	50	very inefficient. Use an event loop for that (such as the L<EV>
74	module): IO::AIO will naturally fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
75		52
76	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
77	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
78	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
…		…
88	yourself, always call C<poll_cb> from within the same thread, or never	65	yourself, always call C<poll_cb> from within the same thread, or never
89	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
90		67
91	=head2 EXAMPLE	68	=head2 EXAMPLE
92		69
93	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
94	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
95		72
96	use Fcntl;	73	use Fcntl;
97	use Event;	74	use EV;
98	use IO::AIO;	75	use IO::AIO;
99		76
100	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
101	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102	poll => 'r',
103	cb => \&IO::AIO::poll_cb);
104		79
105	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
106	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
107	my $fh = shift	82	my $fh = shift
108	or die "error while opening: $!";	83	or die "error while opening: $!";
109		84
110	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
111	my $size = -s $fh;	86	my $size = -s $fh;
…		…
120		95
121	# file contents now in $contents	96	# file contents now in $contents
122	print $contents;	97	print $contents;
123		98
124	# exit event loop and program	99	# exit event loop and program
125	Event::unloop;	100	EV::unloop;
126	};	101	};
127	};	102	};
128		103
129	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
130	# check for sockets etc. etc.	105	# check for sockets etc. etc.
131		106
132	# process events as long as there are some:	107	# process events as long as there are some:
133	Event::loop;	108	EV::loop;
134		109
135	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
136		111
137	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
138	directly visible to Perl.	113	directly visible to Perl.
…		…
188		163
189	package IO::AIO;	164	package IO::AIO;
190		165
191	use Carp ();	166	use Carp ();
192		167
193	no warnings;	168	use common::sense;
194	use strict 'vars';
195		169
196	use base 'Exporter';	170	use base 'Exporter';
197		171
198	BEGIN {	172	BEGIN {
199	our $VERSION = '2.6';	173	our $VERSION = '3.8';
200		174
201	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
202	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
203	aio_readlink aio_sync aio_fsync aio_fdatasync aio_readahead aio_rename aio_link	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
		178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		179	aio_rename aio_link aio_move aio_copy aio_group
204	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
205	aio_chown aio_chmod aio_utime aio_truncate);	181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs);
		184
206	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
207	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
208	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle idle_timeout
209	nreqs nready npending nthreads	188	nreqs nready npending nthreads
210	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
211		194
212	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
213		196
214	require XSLoader;	197	require XSLoader;
215	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
216	}	199	}
217		200
218	=head1 FUNCTIONS	201	=head1 FUNCTIONS
		202
		203	=head2 QUICK OVERVIEW
		204
		205	This section simply lists the prototypes of the most important functions
		206	for quick reference. See the following sections for function-by-function
		207	documentation.
		208
		209	aio_open $pathname, $flags, $mode, $callback->($fh)
		210	aio_close $fh, $callback->($status)
		211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		214	aio_readahead $fh,$offset,$length, $callback->($retval)
		215	aio_stat $fh_or_path, $callback->($status)
		216	aio_lstat $fh, $callback->($status)
		217	aio_statvfs $fh_or_path, $callback->($statvfs)
		218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		220	aio_truncate $fh_or_path, $offset, $callback->($status)
		221	aio_chmod $fh_or_path, $mode, $callback->($status)
		222	aio_unlink $pathname, $callback->($status)
		223	aio_mknod $path, $mode, $dev, $callback->($status)
		224	aio_link $srcpath, $dstpath, $callback->($status)
		225	aio_symlink $srcpath, $dstpath, $callback->($status)
		226	aio_readlink $path, $callback->($link)
		227	aio_rename $srcpath, $dstpath, $callback->($status)
		228	aio_mkdir $pathname, $mode, $callback->($status)
		229	aio_rmdir $pathname, $callback->($status)
		230	aio_readdir $pathname, $callback->($entries)
		231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		234	aio_load $path, $data, $callback->($status)
		235	aio_copy $srcpath, $dstpath, $callback->($status)
		236	aio_move $srcpath, $dstpath, $callback->($status)
		237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		238	aio_rmtree $path, $callback->($status)
		239	aio_sync $callback->($status)
		240	aio_fsync $fh, $callback->($status)
		241	aio_fdatasync $fh, $callback->($status)
		242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		243	aio_pathsync $path, $callback->($status)
		244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		247	aio_mlockall $flags, $callback->($status)
		248	aio_group $callback->(...)
		249	aio_nop $callback->()
		250
		251	$prev_pri = aioreq_pri [$pri]
		252	aioreq_nice $pri_adjust
		253
		254	IO::AIO::poll_wait
		255	IO::AIO::poll_cb
		256	IO::AIO::poll
		257	IO::AIO::flush
		258	IO::AIO::max_poll_reqs $nreqs
		259	IO::AIO::max_poll_time $seconds
		260	IO::AIO::min_parallel $nthreads
		261	IO::AIO::max_parallel $nthreads
		262	IO::AIO::max_idle $nthreads
		263	IO::AIO::idle_timeout $seconds
		264	IO::AIO::max_outstanding $maxreqs
		265	IO::AIO::nreqs
		266	IO::AIO::nready
		267	IO::AIO::npending
		268
		269	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		270	IO::AIO::fadvise $fh, $offset, $len, $advice
		271	IO::AIO::madvise $scalar, $offset, $length, $advice
		272	IO::AIO::mprotect $scalar, $offset, $length, $protect
		273	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		274	IO::AIO::munlockall
219		275
220	=head2 AIO REQUEST FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
221		277
222	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
223	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
224	and they all accept an additional (and optional) C<$callback> argument	280	and they all accept an additional (and optional) C<$callback> argument
225	which must be a code reference. This code reference will get called with	281	which must be a code reference. This code reference will get called with
226	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	282	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
227	perl, which usually delivers "false") as it's sole argument when the given	283	perl, which usually delivers "false") as its sole argument after the given
228	syscall has been executed asynchronously.	284	syscall has been executed asynchronously.
229		285
230	All functions expecting a filehandle keep a copy of the filehandle	286	All functions expecting a filehandle keep a copy of the filehandle
231	internally until the request has finished.	287	internally until the request has finished.
232		288
…		…
246	your pathnames to the locale (or other) encoding in effect in the user	302	your pathnames to the locale (or other) encoding in effect in the user
247	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	303	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
248	use something else to ensure your scalar has the correct contents.	304	use something else to ensure your scalar has the correct contents.
249		305
250	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
251	handles correctly wether it is set or not.	307	handles correctly whether it is set or not.
252		308
253	=over 4	309	=over 4
254		310
255	=item $prev_pri = aioreq_pri [$pri]	311	=item $prev_pri = aioreq_pri [$pri]
256		312
…		…
303	by the umask in effect then the request is being executed, so better never	359	by the umask in effect then the request is being executed, so better never
304	change the umask.	360	change the umask.
305		361
306	Example:	362	Example:
307		363
308	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
309	if ($_[0]) {	365	if ($_[0]) {
310	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
311	...	367	...
312	} else {	368	} else {
313	die "open failed: $!\n";	369	die "open failed: $!\n";
…		…
319		375
320	Asynchronously close a file and call the callback with the result	376	Asynchronously close a file and call the callback with the result
321	code.	377	code.
322		378
323	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on	379	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
324	closing the file descriptor associated with the filehandle itself. Here is	380	closing the file descriptor associated with the filehandle itself.
325	what aio_close will try:
326		381
327	1. dup()licate the fd	382	Therefore, C<aio_close> will not close the filehandle - instead it will
328	2. asynchronously close() the duplicated fd	383	use dup2 to overwrite the file descriptor with the write-end of a pipe
329	3. dup()licate the fd once more	384	(the pipe fd will be created on demand and will be cached).
330	4. let perl close() the filehandle
331	5. asynchronously close the duplicated fd
332		385
333	The idea is that the first close() flushes stuff to disk that closing an	386	Or in other words: the file descriptor will be closed, but it will not be
334	fd will flush, so when perl closes the fd, nothing much will need to be	387	free for reuse until the perl filehandle is closed.
335	flushed. The second async. close() will then flush stuff to disk that
336	closing the last fd to the file will flush.
337
338	Just FYI, SuSv3 has this to say on close:
339
340	All outstanding record locks owned by the process on the file
341	associated with the file descriptor shall be removed.
342
343	If fildes refers to a socket, close() shall cause the socket to be
344	destroyed. ... close() shall block for up to the current linger
345	interval until all data is transmitted.
346	[this actually sounds like a specification bug, but who knows]
347
348	And at least Linux additionally actually flushes stuff on every close,
349	even when the file itself is still open.
350
351	Sounds enourmously inefficient and complicated? Yes... please show me how
352	to nuke perl's fd out of existence...
353		388
354	=cut	389	=cut
355		390
356	sub aio_close($;$) {
357	aio_block {
358	my ($fh, $cb) = @_;
359
360	my $pri = aioreq_pri;
361	my $grp = aio_group $cb;
362
363	my $fd = fileno $fh;
364
365	defined $fd or Carp::croak "aio_close called with fd-less filehandle";
366
367	# if the dups fail we will simply get EBADF
368	my $fd2 = _dup $fd;
369	aioreq_pri $pri;
370	add $grp _aio_close $fd2, sub {
371	my $fd2 = _dup $fd;
372	close $fh;
373	aioreq_pri $pri;
374	add $grp _aio_close $fd2, sub {
375	$grp->result ($_[0]);
376	};
377	};
378
379	$grp
380	}
381	}
382
383
384	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	391	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
385		392
386	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	393	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
387		394
388	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>	395	Reads or writes C<$length> bytes from or to the specified C<$fh> and
389	into the scalar given by C<$data> and offset C<$dataoffset> and calls the	396	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
390	callback without the actual number of bytes read (or -1 on error, just	397	and calls the callback without the actual number of bytes read (or -1 on
391	like the syscall).	398	error, just like the syscall).
		399
		400	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		401	offset plus the actual number of bytes read.
392		402
393	If C<$offset> is undefined, then the current file descriptor offset will	403	If C<$offset> is undefined, then the current file descriptor offset will
394	be used (and updated), otherwise the file descriptor offset will not be	404	be used (and updated), otherwise the file descriptor offset will not be
395	changed by these calls.	405	changed by these calls.
396		406
397	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.	407	If C<$length> is undefined in C<aio_write>, use the remaining length of
		408	C<$data>.
398		409
399	If C<$dataoffset> is less than zero, it will be counted from the end of	410	If C<$dataoffset> is less than zero, it will be counted from the end of
400	C<$data>.	411	C<$data>.
401		412
402	The C<$data> scalar I<MUST NOT> be modified in any way while the request	413	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
418	reading at byte offset C<$in_offset>, and starts writing at the current	429	reading at byte offset C<$in_offset>, and starts writing at the current
419	file offset of C<$out_fh>. Because of that, it is not safe to issue more	430	file offset of C<$out_fh>. Because of that, it is not safe to issue more
420	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	431	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
421	other.	432	other.
422		433
		434	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		435	are written, and there is no way to find out how many bytes have been read
		436	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
		437	bytes written to C<$out_fh>. Only if the result value equals C<$length>
		438	one can assume that C<$length> bytes have been read.
		439
		440	Unlike with other C<aio_> functions, it makes a lot of sense to use
		441	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		442	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		443	the socket I/O will be non-blocking. Note, however, that you can run into
		444	a trap where C<aio_sendfile> reads some data with readahead, then fails
		445	to write all data, and when the socket is ready the next time, the data
		446	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		447	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		448	much better.
		449
423	This call tries to make use of a native C<sendfile> syscall to provide	450	This call tries to make use of a native C<sendfile> syscall to provide
424	zero-copy operation. For this to work, C<$out_fh> should refer to a	451	zero-copy operation. For this to work, C<$out_fh> should refer to a
425	socket, and C<$in_fh> should refer to mmap'able file.	452	socket, and C<$in_fh> should refer to an mmap'able file.
426		453
427	If the native sendfile call fails or is not implemented, it will be	454	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		455	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
428	emulated, so you can call C<aio_sendfile> on any type of filehandle	456	it will be emulated, so you can call C<aio_sendfile> on any type of
429	regardless of the limitations of the operating system.	457	filehandle regardless of the limitations of the operating system.
430
431	Please note, however, that C<aio_sendfile> can read more bytes from
432	C<$in_fh> than are written, and there is no way to find out how many
433	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
434	provides the number of bytes written to C<$out_fh>. Only if the result
435	value equals C<$length> one can assume that C<$length> bytes have been
436	read.
437		458
438		459
439	=item aio_readahead $fh,$offset,$length, $callback->($retval)	460	=item aio_readahead $fh,$offset,$length, $callback->($retval)
440		461
441	C<aio_readahead> populates the page cache with data from a file so that	462	C<aio_readahead> populates the page cache with data from a file so that
…		…
464		485
465	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	486	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
466	error when stat'ing a large file, the results will be silently truncated	487	error when stat'ing a large file, the results will be silently truncated
467	unless perl itself is compiled with large file support.	488	unless perl itself is compiled with large file support.
468		489
		490	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		491	following constants and functions (if not implemented, the constants will
		492	be C<0> and the functions will either C<croak> or fall back on traditional
		493	behaviour).
		494
		495	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		496	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		497	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		498
469	Example: Print the length of F</etc/passwd>:	499	Example: Print the length of F</etc/passwd>:
470		500
471	aio_stat "/etc/passwd", sub {	501	aio_stat "/etc/passwd", sub {
472	$_[0] and die "stat failed: $!";	502	$_[0] and die "stat failed: $!";
473	print "size is ", -s _, "\n";	503	print "size is ", -s _, "\n";
474	};	504	};
475		505
476		506
		507	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		508
		509	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		510	whether a file handle or path was passed.
		511
		512	On success, the callback is passed a hash reference with the following
		513	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		514	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		515	is passed.
		516
		517	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		518	C<ST_NOSUID>.
		519
		520	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		521	their correct value when available, or to C<0> on systems that do
		522	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		523	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		524	C<ST_NODIRATIME> and C<ST_RELATIME>.
		525
		526	Example: stat C</wd> and dump out the data if successful.
		527
		528	aio_statvfs "/wd", sub {
		529	my $f = $_[0]
		530	or die "statvfs: $!";
		531
		532	use Data::Dumper;
		533	say Dumper $f;
		534	};
		535
		536	# result:
		537	{
		538	bsize => 1024,
		539	bfree => 4333064312,
		540	blocks => 10253828096,
		541	files => 2050765568,
		542	flag => 4096,
		543	favail => 2042092649,
		544	bavail => 4333064312,
		545	ffree => 2042092649,
		546	namemax => 255,
		547	frsize => 1024,
		548	fsid => 1810
		549	}
		550
		551
477	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	552	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
478		553
479	Works like perl's C<utime> function (including the special case of $atime	554	Works like perl's C<utime> function (including the special case of $atime
480	and $mtime being undef). Fractional times are supported if the underlying	555	and $mtime being undef). Fractional times are supported if the underlying
481	syscalls support them.	556	syscalls support them.
…		…
529		604
530	The only (POSIX-) portable way of calling this function is:	605	The only (POSIX-) portable way of calling this function is:
531		606
532	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	607	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
533		608
		609	See C<aio_stat> for info about some potentially helpful extra constants
		610	and functions.
534		611
535	=item aio_link $srcpath, $dstpath, $callback->($status)	612	=item aio_link $srcpath, $dstpath, $callback->($status)
536		613
537	Asynchronously create a new link to the existing object at C<$srcpath> at	614	Asynchronously create a new link to the existing object at C<$srcpath> at
538	the path C<$dstpath> and call the callback with the result code.	615	the path C<$dstpath> and call the callback with the result code.
…		…
574		651
575	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	652	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
576	directory (i.e. opendir + readdir + closedir). The entries will not be	653	directory (i.e. opendir + readdir + closedir). The entries will not be
577	sorted, and will B<NOT> include the C<.> and C<..> entries.	654	sorted, and will B<NOT> include the C<.> and C<..> entries.
578		655
579	The callback a single argument which is either C<undef> or an array-ref	656	The callback is passed a single argument which is either C<undef> or an
580	with the filenames.	657	array-ref with the filenames.
		658
		659
		660	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		661
		662	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		663	behaviour and output format. In case of an error, C<$entries> will be
		664	C<undef>.
		665
		666	The flags are a combination of the following constants, ORed together (the
		667	flags will also be passed to the callback, possibly modified):
		668
		669	=over 4
		670
		671	=item IO::AIO::READDIR_DENTS
		672
		673	When this flag is off, then the callback gets an arrayref with of names
		674	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		675	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		676	entry in more detail.
		677
		678	C<$name> is the name of the entry.
		679
		680	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		681
		682	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		683	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		684	C<IO::AIO::DT_WHT>.
		685
		686	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		687	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		688	scalars are read-only: you can not modify them.
		689
		690	C<$inode> is the inode number (which might not be exact on systems with 64
		691	bit inode numbers and 32 bit perls). This field has unspecified content on
		692	systems that do not deliver the inode information.
		693
		694	=item IO::AIO::READDIR_DIRS_FIRST
		695
		696	When this flag is set, then the names will be returned in an order where
		697	likely directories come first. This is useful when you need to quickly
		698	find directories, or you want to find all directories while avoiding to
		699	stat() each entry.
		700
		701	If the system returns type information in readdir, then this is used
		702	to find directories directly. Otherwise, likely directories are files
		703	beginning with ".", or otherwise files with no dots, of which files with
		704	short names are tried first.
		705
		706	=item IO::AIO::READDIR_STAT_ORDER
		707
		708	When this flag is set, then the names will be returned in an order
		709	suitable for stat()'ing each one. That is, when you plan to stat()
		710	all files in the given directory, then the returned order will likely
		711	be fastest.
		712
		713	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		714	the likely dirs come first, resulting in a less optimal stat order.
		715
		716	=item IO::AIO::READDIR_FOUND_UNKNOWN
		717
		718	This flag should not be set when calling C<aio_readdirx>. Instead, it
		719	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		720	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		721	C<$type>'s are known, which can be used to speed up some algorithms.
		722
		723	=back
581		724
582		725
583	=item aio_load $path, $data, $callback->($status)	726	=item aio_load $path, $data, $callback->($status)
584		727
585	This is a composite request that tries to fully load the given file into	728	This is a composite request that tries to fully load the given file into
586	memory. Status is the same as with aio_read.	729	memory. Status is the same as with aio_read.
587		730
588	=cut	731	=cut
589		732
590	sub aio_load($$;$) {	733	sub aio_load($$;$) {
591	aio_block {
592	my ($path, undef, $cb) = @_;	734	my ($path, undef, $cb) = @_;
593	my $data = \$_[1];	735	my $data = \$_[1];
594		736
595	my $pri = aioreq_pri;	737	my $pri = aioreq_pri;
596	my $grp = aio_group $cb;	738	my $grp = aio_group $cb;
		739
		740	aioreq_pri $pri;
		741	add $grp aio_open $path, O_RDONLY, 0, sub {
		742	my $fh = shift
		743	or return $grp->result (-1);
597		744
598	aioreq_pri $pri;	745	aioreq_pri $pri;
599	add $grp aio_open $path, O_RDONLY, 0, sub {
600	my $fh = shift
601	or return $grp->result (-1);
602
603	aioreq_pri $pri;
604	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	746	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
605	$grp->result ($_[0]);	747	$grp->result ($_[0]);
606	};
607	};	748	};
608
609	$grp
610	}	749	};
		750
		751	$grp
611	}	752	}
612		753
613	=item aio_copy $srcpath, $dstpath, $callback->($status)	754	=item aio_copy $srcpath, $dstpath, $callback->($status)
614		755
615	Try to copy the I<file> (directories not supported as either source or	756	Try to copy the I<file> (directories not supported as either source or
616	destination) from C<$srcpath> to C<$dstpath> and call the callback with	757	destination) from C<$srcpath> to C<$dstpath> and call the callback with
617	the C<0> (error) or C<-1> ok.	758	a status of C<0> (ok) or C<-1> (error, see C<$!>).
618		759
619	This is a composite request that it creates the destination file with	760	This is a composite request that creates the destination file with
620	mode 0200 and copies the contents of the source file into it using	761	mode 0200 and copies the contents of the source file into it using
621	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	762	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
622	uid/gid, in that order.	763	uid/gid, in that order.
623		764
624	If an error occurs, the partial destination file will be unlinked, if	765	If an error occurs, the partial destination file will be unlinked, if
…		…
626	errors are being ignored.	767	errors are being ignored.
627		768
628	=cut	769	=cut
629		770
630	sub aio_copy($$;$) {	771	sub aio_copy($$;$) {
631	aio_block {
632	my ($src, $dst, $cb) = @_;	772	my ($src, $dst, $cb) = @_;
633		773
634	my $pri = aioreq_pri;	774	my $pri = aioreq_pri;
635	my $grp = aio_group $cb;	775	my $grp = aio_group $cb;
636		776
637	aioreq_pri $pri;	777	aioreq_pri $pri;
638	add $grp aio_open $src, O_RDONLY, 0, sub {	778	add $grp aio_open $src, O_RDONLY, 0, sub {
639	if (my $src_fh = $_[0]) {	779	if (my $src_fh = $_[0]) {
640	my @stat = stat $src_fh;	780	my @stat = stat $src_fh; # hmm, might block over nfs?
641		781
642	aioreq_pri $pri;	782	aioreq_pri $pri;
643	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	783	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
644	if (my $dst_fh = $_[0]) {	784	if (my $dst_fh = $_[0]) {
645	aioreq_pri $pri;	785	aioreq_pri $pri;
646	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	786	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
647	if ($_[0] == $stat[7]) {	787	if ($_[0] == $stat[7]) {
648	$grp->result (0);	788	$grp->result (0);
649	close $src_fh;	789	close $src_fh;
650		790
651	# those should not normally block. should. should.
652	utime $stat[8], $stat[9], $dst;
653	chmod $stat[2] & 07777, $dst_fh;
654	chown $stat[4], $stat[5], $dst_fh;
655	close $dst_fh;
656	} else {	791	my $ch = sub {
657	$grp->result (-1);
658	close $src_fh;
659	close $dst_fh;
660
661	aioreq $pri;	792	aioreq_pri $pri;
		793	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		794	aioreq_pri $pri;
		795	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		796	aioreq_pri $pri;
662	add $grp aio_unlink $dst;	797	add $grp aio_close $dst_fh;
		798	}
		799	};
663	}	800	};
		801
		802	aioreq_pri $pri;
		803	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		804	if ($_[0] < 0 && $! == ENOSYS) {
		805	aioreq_pri $pri;
		806	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		807	} else {
		808	$ch->();
		809	}
		810	};
		811	} else {
		812	$grp->result (-1);
		813	close $src_fh;
		814	close $dst_fh;
		815
		816	aioreq $pri;
		817	add $grp aio_unlink $dst;
664	};	818	}
665	} else {
666	$grp->result (-1);
667	}	819	};
		820	} else {
		821	$grp->result (-1);
668	},	822	}
669
670	} else {
671	$grp->result (-1);
672	}	823	},
		824
		825	} else {
		826	$grp->result (-1);
673	};	827	}
674
675	$grp
676	}	828	};
		829
		830	$grp
677	}	831	}
678		832
679	=item aio_move $srcpath, $dstpath, $callback->($status)	833	=item aio_move $srcpath, $dstpath, $callback->($status)
680		834
681	Try to move the I<file> (directories not supported as either source or	835	Try to move the I<file> (directories not supported as either source or
682	destination) from C<$srcpath> to C<$dstpath> and call the callback with	836	destination) from C<$srcpath> to C<$dstpath> and call the callback with
683	the C<0> (error) or C<-1> ok.	837	a status of C<0> (ok) or C<-1> (error, see C<$!>).
684		838
685	This is a composite request that tries to rename(2) the file first. If	839	This is a composite request that tries to rename(2) the file first; if
686	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	840	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
687	that is successful, unlinking the C<$srcpath>.	841	that is successful, unlinks the C<$srcpath>.
688		842
689	=cut	843	=cut
690		844
691	sub aio_move($$;$) {	845	sub aio_move($$;$) {
692	aio_block {
693	my ($src, $dst, $cb) = @_;	846	my ($src, $dst, $cb) = @_;
694		847
695	my $pri = aioreq_pri;	848	my $pri = aioreq_pri;
696	my $grp = aio_group $cb;	849	my $grp = aio_group $cb;
697		850
698	aioreq_pri $pri;	851	aioreq_pri $pri;
699	add $grp aio_rename $src, $dst, sub {	852	add $grp aio_rename $src, $dst, sub {
700	if ($_[0] && $! == EXDEV) {	853	if ($_[0] && $! == EXDEV) {
701	aioreq_pri $pri;	854	aioreq_pri $pri;
702	add $grp aio_copy $src, $dst, sub {	855	add $grp aio_copy $src, $dst, sub {
703	$grp->result ($_[0]);
704
705	if (!$_[0]) {
706	aioreq_pri $pri;
707	add $grp aio_unlink $src;
708	}
709	};
710	} else {
711	$grp->result ($_[0]);	856	$grp->result ($_[0]);
		857
		858	if (!$_[0]) {
		859	aioreq_pri $pri;
		860	add $grp aio_unlink $src;
		861	}
712	}	862	};
		863	} else {
		864	$grp->result ($_[0]);
713	};	865	}
714
715	$grp
716	}	866	};
		867
		868	$grp
717	}	869	}
718		870
719	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	871	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
720		872
721	Scans a directory (similar to C<aio_readdir>) but additionally tries to	873	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
741		893
742	Implementation notes.	894	Implementation notes.
743		895
744	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	896	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
745		897
		898	If readdir returns file type information, then this is used directly to
		899	find directories.
		900
746	After reading the directory, the modification time, size etc. of the	901	Otherwise, after reading the directory, the modification time, size etc.
747	directory before and after the readdir is checked, and if they match (and	902	of the directory before and after the readdir is checked, and if they
748	isn't the current time), the link count will be used to decide how many	903	match (and isn't the current time), the link count will be used to decide
749	entries are directories (if >= 2). Otherwise, no knowledge of the number	904	how many entries are directories (if >= 2). Otherwise, no knowledge of the
750	of subdirectories will be assumed.	905	number of subdirectories will be assumed.
751		906
752	Then entries will be sorted into likely directories (everything without	907	Then entries will be sorted into likely directories a non-initial dot
753	a non-initial dot currently) and likely non-directories (everything	908	currently) and likely non-directories (see C<aio_readdirx>). Then every
754	else). Then every entry plus an appended C</.> will be C<stat>'ed,	909	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
755	likely directories first. If that succeeds, it assumes that the entry	910	in order of their inode numbers. If that succeeds, it assumes that the
756	is a directory or a symlink to directory (which will be checked	911	entry is a directory or a symlink to directory (which will be checked
757	seperately). This is often faster than stat'ing the entry itself because	912	seperately). This is often faster than stat'ing the entry itself because
758	filesystems might detect the type of the entry without reading the inode	913	filesystems might detect the type of the entry without reading the inode
759	data (e.g. ext2fs filetype feature).	914	data (e.g. ext2fs filetype feature), even on systems that cannot return
		915	the filetype information on readdir.
760		916
761	If the known number of directories (link count - 2) has been reached, the	917	If the known number of directories (link count - 2) has been reached, the
762	rest of the entries is assumed to be non-directories.	918	rest of the entries is assumed to be non-directories.
763		919
764	This only works with certainty on POSIX (= UNIX) filesystems, which	920	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
769	directory counting heuristic.	925	directory counting heuristic.
770		926
771	=cut	927	=cut
772		928
773	sub aio_scandir($$;$) {	929	sub aio_scandir($$;$) {
774	aio_block {
775	my ($path, $maxreq, $cb) = @_;	930	my ($path, $maxreq, $cb) = @_;
776		931
777	my $pri = aioreq_pri;	932	my $pri = aioreq_pri;
778		933
779	my $grp = aio_group $cb;	934	my $grp = aio_group $cb;
780		935
781	$maxreq = 4 if $maxreq <= 0;	936	$maxreq = 4 if $maxreq <= 0;
782		937
783	# stat once	938	# stat once
		939	aioreq_pri $pri;
		940	add $grp aio_stat $path, sub {
		941	return $grp->result () if $_[0];
		942	my $now = time;
		943	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		944
		945	# read the directory entries
784	aioreq_pri $pri;	946	aioreq_pri $pri;
785	add $grp aio_stat $path, sub {	947	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		948	my $entries = shift
786	return $grp->result () if $_[0];	949	or return $grp->result ();
787	my $now = time;
788	my $hash1 = join ":", (stat _)[0,1,3,7,9];
789		950
790	# read the directory entries	951	# stat the dir another time
791	aioreq_pri $pri;	952	aioreq_pri $pri;
792	add $grp aio_readdir $path, sub {
793	my $entries = shift
794	or return $grp->result ();
795
796	# stat the dir another time
797	aioreq_pri $pri;
798	add $grp aio_stat $path, sub {	953	add $grp aio_stat $path, sub {
799	my $hash2 = join ":", (stat _)[0,1,3,7,9];	954	my $hash2 = join ":", (stat _)[0,1,3,7,9];
800		955
801	my $ndirs;	956	my $ndirs;
802		957
803	# take the slow route if anything looks fishy	958	# take the slow route if anything looks fishy
804	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	959	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
805	$ndirs = -1;	960	$ndirs = -1;
806	} else {	961	} else {
807	# if nlink == 2, we are finished	962	# if nlink == 2, we are finished
808	# on non-posix-fs's, we rely on nlink < 2	963	# for non-posix-fs's, we rely on nlink < 2
809	$ndirs = (stat _)[3] - 2	964	$ndirs = (stat _)[3] - 2
810	or return $grp->result ([], $entries);	965	or return $grp->result ([], $entries);
811	}	966	}
812		967
813	# sort into likely dirs and likely nondirs
814	# dirs == files without ".", short entries first
815	$entries = [map $_->[0],
816	sort { $b->[1] cmp $a->[1] }
817	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
818	@$entries];
819
820	my (@dirs, @nondirs);	968	my (@dirs, @nondirs);
821		969
822	my $statgrp = add $grp aio_group sub {	970	my $statgrp = add $grp aio_group sub {
823	$grp->result (\@dirs, \@nondirs);	971	$grp->result (\@dirs, \@nondirs);
824	};	972	};
825		973
826	limit $statgrp $maxreq;	974	limit $statgrp $maxreq;
827	feed $statgrp sub {	975	feed $statgrp sub {
828	return unless @$entries;	976	return unless @$entries;
829	my $entry = pop @$entries;	977	my $entry = shift @$entries;
830		978
831	aioreq_pri $pri;	979	aioreq_pri $pri;
832	add $statgrp aio_stat "$path/$entry/.", sub {	980	add $statgrp aio_stat "$path/$entry/.", sub {
833	if ($_[0] < 0) {	981	if ($_[0] < 0) {
834	push @nondirs, $entry;	982	push @nondirs, $entry;
835	} else {	983	} else {
836	# need to check for real directory	984	# need to check for real directory
837	aioreq_pri $pri;	985	aioreq_pri $pri;
838	add $statgrp aio_lstat "$path/$entry", sub {	986	add $statgrp aio_lstat "$path/$entry", sub {
839	if (-d _) {	987	if (-d _) {
840	push @dirs, $entry;	988	push @dirs, $entry;
841		989
842	unless (--$ndirs) {	990	unless (--$ndirs) {
843	push @nondirs, @$entries;	991	push @nondirs, @$entries;
844	feed $statgrp;	992	feed $statgrp;
845	}
846	} else {
847	push @nondirs, $entry;
848	}	993	}
		994	} else {
		995	push @nondirs, $entry;
849	}	996	}
850	}	997	}
851	};	998	}
852	};	999	};
853	};	1000	};
854	};	1001	};
855	};	1002	};
856
857	$grp
858	}	1003	};
		1004
		1005	$grp
859	}	1006	}
860		1007
861	=item aio_rmtree $path, $callback->($status)	1008	=item aio_rmtree $path, $callback->($status)
862		1009
863	Delete a directory tree starting (and including) C<$path>, return the	1010	Delete a directory tree starting (and including) C<$path>, return the
…		…
867		1014
868	=cut	1015	=cut
869		1016
870	sub aio_rmtree;	1017	sub aio_rmtree;
871	sub aio_rmtree($;$) {	1018	sub aio_rmtree($;$) {
872	aio_block {
873	my ($path, $cb) = @_;	1019	my ($path, $cb) = @_;
874		1020
875	my $pri = aioreq_pri;	1021	my $pri = aioreq_pri;
876	my $grp = aio_group $cb;	1022	my $grp = aio_group $cb;
877		1023
878	aioreq_pri $pri;	1024	aioreq_pri $pri;
879	add $grp aio_scandir $path, 0, sub {	1025	add $grp aio_scandir $path, 0, sub {
880	my ($dirs, $nondirs) = @_;	1026	my ($dirs, $nondirs) = @_;
881		1027
882	my $dirgrp = aio_group sub {	1028	my $dirgrp = aio_group sub {
883	add $grp aio_rmdir $path, sub {	1029	add $grp aio_rmdir $path, sub {
884	$grp->result ($_[0]);	1030	$grp->result ($_[0]);
885	};
886	};	1031	};
887
888	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
889	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
890
891	add $grp $dirgrp;
892	};	1032	};
893		1033
894	$grp	1034	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1035	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1036
		1037	add $grp $dirgrp;
895	}	1038	};
		1039
		1040	$grp
896	}	1041	}
897		1042
898	=item aio_sync $callback->($status)	1043	=item aio_sync $callback->($status)
899		1044
900	Asynchronously call sync and call the callback when finished.	1045	Asynchronously call sync and call the callback when finished.
…		…
909	Asynchronously call fdatasync on the given filehandle and call the	1054	Asynchronously call fdatasync on the given filehandle and call the
910	callback with the fdatasync result code.	1055	callback with the fdatasync result code.
911		1056
912	If this call isn't available because your OS lacks it or it couldn't be	1057	If this call isn't available because your OS lacks it or it couldn't be
913	detected, it will be emulated by calling C<fsync> instead.	1058	detected, it will be emulated by calling C<fsync> instead.
		1059
		1060	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1061
		1062	Sync the data portion of the file specified by C<$offset> and C<$length>
		1063	to disk (but NOT the metadata), by calling the Linux-specific
		1064	sync_file_range call. If sync_file_range is not available or it returns
		1065	ENOSYS, then fdatasync or fsync is being substituted.
		1066
		1067	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1068	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1069	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1070	manpage for details.
		1071
		1072	=item aio_pathsync $path, $callback->($status)
		1073
		1074	This request tries to open, fsync and close the given path. This is a
		1075	composite request intended to sync directories after directory operations
		1076	(E.g. rename). This might not work on all operating systems or have any
		1077	specific effect, but usually it makes sure that directory changes get
		1078	written to disc. It works for anything that can be opened for read-only,
		1079	not just directories.
		1080
		1081	Future versions of this function might fall back to other methods when
		1082	C<fsync> on the directory fails (such as calling C<sync>).
		1083
		1084	Passes C<0> when everything went ok, and C<-1> on error.
		1085
		1086	=cut
		1087
		1088	sub aio_pathsync($;$) {
		1089	my ($path, $cb) = @_;
		1090
		1091	my $pri = aioreq_pri;
		1092	my $grp = aio_group $cb;
		1093
		1094	aioreq_pri $pri;
		1095	add $grp aio_open $path, O_RDONLY, 0, sub {
		1096	my ($fh) = @_;
		1097	if ($fh) {
		1098	aioreq_pri $pri;
		1099	add $grp aio_fsync $fh, sub {
		1100	$grp->result ($_[0]);
		1101
		1102	aioreq_pri $pri;
		1103	add $grp aio_close $fh;
		1104	};
		1105	} else {
		1106	$grp->result (-1);
		1107	}
		1108	};
		1109
		1110	$grp
		1111	}
		1112
		1113	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1114
		1115	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1116	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1117	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1118	scalar must only be modified in-place while an aio operation is pending on
		1119	it).
		1120
		1121	It calls the C<msync> function of your OS, if available, with the memory
		1122	area starting at C<$offset> in the string and ending C<$length> bytes
		1123	later. If C<$length> is negative, counts from the end, and if C<$length>
		1124	is C<undef>, then it goes till the end of the string. The flags can be
		1125	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1126	C<IO::AIO::MS_SYNC>.
		1127
		1128	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1129
		1130	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1131	scalars.
		1132
		1133	It touches (reads or writes) all memory pages in the specified
		1134	range inside the scalar. All caveats and parameters are the same
		1135	as for C<aio_msync>, above, except for flags, which must be either
		1136	C<0> (which reads all pages and ensures they are instantiated) or
		1137	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1138	writing an octet from it, which dirties the page).
		1139
		1140	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1141
		1142	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1143	scalars.
		1144
		1145	It reads in all the pages of the underlying storage into memory (if any)
		1146	and locks them, so they are not getting swapped/paged out or removed.
		1147
		1148	If C<$length> is undefined, then the scalar will be locked till the end.
		1149
		1150	On systems that do not implement C<mlock>, this function returns C<-1>
		1151	and sets errno to C<ENOSYS>.
		1152
		1153	Note that the corresponding C<munlock> is synchronous and is
		1154	documented under L<MISCELLANEOUS FUNCTIONS>.
		1155
		1156	Example: open a file, mmap and mlock it - both will be undone when
		1157	C<$data> gets destroyed.
		1158
		1159	open my $fh, "<", $path or die "$path: $!";
		1160	my $data;
		1161	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1162	aio_mlock $data; # mlock in background
		1163
		1164	=item aio_mlockall $flags, $callback->($status)
		1165
		1166	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1167	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1168
		1169	On systems that do not implement C<mlockall>, this function returns C<-1>
		1170	and sets errno to C<ENOSYS>.
		1171
		1172	Note that the corresponding C<munlockall> is synchronous and is
		1173	documented under L<MISCELLANEOUS FUNCTIONS>.
		1174
		1175	Example: asynchronously lock all current and future pages into memory.
		1176
		1177	aio_mlockall IO::AIO::MCL_FUTURE;
914		1178
915	=item aio_group $callback->(...)	1179	=item aio_group $callback->(...)
916		1180
917	This is a very special aio request: Instead of doing something, it is a	1181	This is a very special aio request: Instead of doing something, it is a
918	container for other aio requests, which is useful if you want to bundle	1182	container for other aio requests, which is useful if you want to bundle
…		…
968	=item cancel $req	1232	=item cancel $req
969		1233
970	Cancels the request, if possible. Has the effect of skipping execution	1234	Cancels the request, if possible. Has the effect of skipping execution
971	when entering the B<execute> state and skipping calling the callback when	1235	when entering the B<execute> state and skipping calling the callback when
972	entering the the B<result> state, but will leave the request otherwise	1236	entering the the B<result> state, but will leave the request otherwise
973	untouched. That means that requests that currently execute will not be	1237	untouched (with the exception of readdir). That means that requests that
974	stopped and resources held by the request will not be freed prematurely.	1238	currently execute will not be stopped and resources held by the request
		1239	will not be freed prematurely.
975		1240
976	=item cb $req $callback->(...)	1241	=item cb $req $callback->(...)
977		1242
978	Replace (or simply set) the callback registered to the request.	1243	Replace (or simply set) the callback registered to the request.
979		1244
…		…
1030	Their lifetime, simplified, looks like this: when they are empty, they	1295	Their lifetime, simplified, looks like this: when they are empty, they
1031	will finish very quickly. If they contain only requests that are in the	1296	will finish very quickly. If they contain only requests that are in the
1032	C<done> state, they will also finish. Otherwise they will continue to	1297	C<done> state, they will also finish. Otherwise they will continue to
1033	exist.	1298	exist.
1034		1299
1035	That means after creating a group you have some time to add requests. And	1300	That means after creating a group you have some time to add requests
1036	in the callbacks of those requests, you can add further requests to the	1301	(precisely before the callback has been invoked, which is only done within
1037	group. And only when all those requests have finished will the the group	1302	the C<poll_cb>). And in the callbacks of those requests, you can add
1038	itself finish.	1303	further requests to the group. And only when all those requests have
		1304	finished will the the group itself finish.
1039		1305
1040	=over 4	1306	=over 4
1041		1307
1042	=item add $grp ...	1308	=item add $grp ...
1043		1309
…		…
1052	=item $grp->cancel_subs	1318	=item $grp->cancel_subs
1053		1319
1054	Cancel all subrequests and clears any feeder, but not the group request	1320	Cancel all subrequests and clears any feeder, but not the group request
1055	itself. Useful when you queued a lot of events but got a result early.	1321	itself. Useful when you queued a lot of events but got a result early.
1056		1322
		1323	The group request will finish normally (you cannot add requests to the
		1324	group).
		1325
1057	=item $grp->result (...)	1326	=item $grp->result (...)
1058		1327
1059	Set the result value(s) that will be passed to the group callback when all	1328	Set the result value(s) that will be passed to the group callback when all
1060	subrequests have finished and set thre groups errno to the current value	1329	subrequests have finished and set the groups errno to the current value
1061	of errno (just like calling C<errno> without an error number). By default,	1330	of errno (just like calling C<errno> without an error number). By default,
1062	no argument will be passed and errno is zero.	1331	no argument will be passed and errno is zero.
1063		1332
1064	=item $grp->errno ([$errno])	1333	=item $grp->errno ([$errno])
1065		1334
…		…
1076	=item feed $grp $callback->($grp)	1345	=item feed $grp $callback->($grp)
1077		1346
1078	Sets a feeder/generator on this group: every group can have an attached	1347	Sets a feeder/generator on this group: every group can have an attached
1079	generator that generates requests if idle. The idea behind this is that,	1348	generator that generates requests if idle. The idea behind this is that,
1080	although you could just queue as many requests as you want in a group,	1349	although you could just queue as many requests as you want in a group,
1081	this might starve other requests for a potentially long time. For	1350	this might starve other requests for a potentially long time. For example,
1082	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1351	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1083	requests, delaying any later requests for a long time.	1352	delaying any later requests for a long time.
1084		1353
1085	To avoid this, and allow incremental generation of requests, you can	1354	To avoid this, and allow incremental generation of requests, you can
1086	instead a group and set a feeder on it that generates those requests. The	1355	instead a group and set a feeder on it that generates those requests. The
1087	feed callback will be called whenever there are few enough (see C<limit>,	1356	feed callback will be called whenever there are few enough (see C<limit>,
1088	below) requests active in the group itself and is expected to queue more	1357	below) requests active in the group itself and is expected to queue more
…		…
1092	not impose any limits).	1361	not impose any limits).
1093		1362
1094	If the feed does not queue more requests when called, it will be	1363	If the feed does not queue more requests when called, it will be
1095	automatically removed from the group.	1364	automatically removed from the group.
1096		1365
1097	If the feed limit is C<0>, it will be set to C<2> automatically.	1366	If the feed limit is C<0> when this method is called, it will be set to
		1367	C<2> automatically.
1098		1368
1099	Example:	1369	Example:
1100		1370
1101	# stat all files in @files, but only ever use four aio requests concurrently:	1371	# stat all files in @files, but only ever use four aio requests concurrently:
1102		1372
…		…
1114	Sets the feeder limit for the group: The feeder will be called whenever	1384	Sets the feeder limit for the group: The feeder will be called whenever
1115	the group contains less than this many requests.	1385	the group contains less than this many requests.
1116		1386
1117	Setting the limit to C<0> will pause the feeding process.	1387	Setting the limit to C<0> will pause the feeding process.
1118		1388
		1389	The default value for the limit is C<0>, but note that setting a feeder
		1390	automatically bumps it up to C<2>.
		1391
1119	=back	1392	=back
1120		1393
1121	=head2 SUPPORT FUNCTIONS	1394	=head2 SUPPORT FUNCTIONS
1122		1395
1123	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1396	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1125	=over 4	1398	=over 4
1126		1399
1127	=item $fileno = IO::AIO::poll_fileno	1400	=item $fileno = IO::AIO::poll_fileno
1128		1401
1129	Return the I<request result pipe file descriptor>. This filehandle must be	1402	Return the I<request result pipe file descriptor>. This filehandle must be
1130	polled for reading by some mechanism outside this module (e.g. Event or	1403	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1131	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1404	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1132	to call C<poll_cb> to check the results.	1405	you have to call C<poll_cb> to check the results.
1133		1406
1134	See C<poll_cb> for an example.	1407	See C<poll_cb> for an example.
1135		1408
1136	=item IO::AIO::poll_cb	1409	=item IO::AIO::poll_cb
1137		1410
1138	Process some outstanding events on the result pipe. You have to call this	1411	Process some outstanding events on the result pipe. You have to call this
1139	regularly. Returns the number of events processed. Returns immediately	1412	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1413	returned earlier for whatever reason. Returns immediately when no events
1140	when no events are outstanding. The amount of events processed depends on	1414	are outstanding. The amount of events processed depends on the settings of
1141	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1415	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1142		1416
1143	If not all requests were processed for whatever reason, the filehandle	1417	If not all requests were processed for whatever reason, the filehandle
1144	will still be ready when C<poll_cb> returns.	1418	will still be ready when C<poll_cb> returns, so normally you don't have to
		1419	do anything special to have it called later.
1145		1420
1146	Example: Install an Event watcher that automatically calls	1421	Example: Install an Event watcher that automatically calls
1147	IO::AIO::poll_cb with high priority:	1422	IO::AIO::poll_cb with high priority (more examples can be found in the
		1423	SYNOPSIS section, at the top of this document):
1148		1424
1149	Event->io (fd => IO::AIO::poll_fileno,	1425	Event->io (fd => IO::AIO::poll_fileno,
1150	poll => 'r', async => 1,	1426	poll => 'r', async => 1,
1151	cb => \&IO::AIO::poll_cb);	1427	cb => \&IO::AIO::poll_cb);
		1428
		1429	=item IO::AIO::poll_wait
		1430
		1431	If there are any outstanding requests and none of them in the result
		1432	phase, wait till the result filehandle becomes ready for reading (simply
		1433	does a C<select> on the filehandle. This is useful if you want to
		1434	synchronously wait for some requests to finish).
		1435
		1436	See C<nreqs> for an example.
		1437
		1438	=item IO::AIO::poll
		1439
		1440	Waits until some requests have been handled.
		1441
		1442	Returns the number of requests processed, but is otherwise strictly
		1443	equivalent to:
		1444
		1445	IO::AIO::poll_wait, IO::AIO::poll_cb
		1446
		1447	=item IO::AIO::flush
		1448
		1449	Wait till all outstanding AIO requests have been handled.
		1450
		1451	Strictly equivalent to:
		1452
		1453	IO::AIO::poll_wait, IO::AIO::poll_cb
		1454	while IO::AIO::nreqs;
1152		1455
1153	=item IO::AIO::max_poll_reqs $nreqs	1456	=item IO::AIO::max_poll_reqs $nreqs
1154		1457
1155	=item IO::AIO::max_poll_time $seconds	1458	=item IO::AIO::max_poll_time $seconds
1156		1459
…		…
1181	# use a low priority so other tasks have priority	1484	# use a low priority so other tasks have priority
1182	Event->io (fd => IO::AIO::poll_fileno,	1485	Event->io (fd => IO::AIO::poll_fileno,
1183	poll => 'r', nice => 1,	1486	poll => 'r', nice => 1,
1184	cb => &IO::AIO::poll_cb);	1487	cb => &IO::AIO::poll_cb);
1185		1488
1186	=item IO::AIO::poll_wait
1187
1188	If there are any outstanding requests and none of them in the result
1189	phase, wait till the result filehandle becomes ready for reading (simply
1190	does a C<select> on the filehandle. This is useful if you want to
1191	synchronously wait for some requests to finish).
1192
1193	See C<nreqs> for an example.
1194
1195	=item IO::AIO::poll
1196
1197	Waits until some requests have been handled.
1198
1199	Returns the number of requests processed, but is otherwise strictly
1200	equivalent to:
1201
1202	IO::AIO::poll_wait, IO::AIO::poll_cb
1203
1204	=item IO::AIO::flush
1205
1206	Wait till all outstanding AIO requests have been handled.
1207
1208	Strictly equivalent to:
1209
1210	IO::AIO::poll_wait, IO::AIO::poll_cb
1211	while IO::AIO::nreqs;
1212
1213	=back	1489	=back
1214		1490
1215	=head3 CONTROLLING THE NUMBER OF THREADS	1491	=head3 CONTROLLING THE NUMBER OF THREADS
1216		1492
1217	=over	1493	=over
…		…
1250		1526
1251	Under normal circumstances you don't need to call this function.	1527	Under normal circumstances you don't need to call this function.
1252		1528
1253	=item IO::AIO::max_idle $nthreads	1529	=item IO::AIO::max_idle $nthreads
1254		1530
1255	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1531	Limit the number of threads (default: 4) that are allowed to idle
1256	threads that did not get a request to process within 10 seconds). That	1532	(i.e., threads that did not get a request to process within the idle
1257	means if a thread becomes idle while C<$nthreads> other threads are also	1533	timeout (default: 10 seconds). That means if a thread becomes idle while
1258	idle, it will free its resources and exit.	1534	C<$nthreads> other threads are also idle, it will free its resources and
		1535	exit.
1259		1536
1260	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1537	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1261	to allow for extremely high load situations, but want to free resources	1538	to allow for extremely high load situations, but want to free resources
1262	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1539	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1263		1540
1264	The default is probably ok in most situations, especially if thread	1541	The default is probably ok in most situations, especially if thread
1265	creation is fast. If thread creation is very slow on your system you might	1542	creation is fast. If thread creation is very slow on your system you might
1266	want to use larger values.	1543	want to use larger values.
1267		1544
		1545	=item IO::AIO::idle_timeout $seconds
		1546
		1547	Sets the minimum idle timeout (default 10) after which worker threads are
		1548	allowed to exit. SEe C<IO::AIO::max_idle>.
		1549
1268	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1550	=item IO::AIO::max_outstanding $maxreqs
1269		1551
1270	This is a very bad function to use in interactive programs because it	1552	This is a very bad function to use in interactive programs because it
1271	blocks, and a bad way to reduce concurrency because it is inexact: Better	1553	blocks, and a bad way to reduce concurrency because it is inexact: Better
1272	use an C<aio_group> together with a feed callback.	1554	use an C<aio_group> together with a feed callback.
1273		1555
…		…
1278		1560
1279	The default value is very large, so there is no practical limit on the	1561	The default value is very large, so there is no practical limit on the
1280	number of outstanding requests.	1562	number of outstanding requests.
1281		1563
1282	You can still queue as many requests as you want. Therefore,	1564	You can still queue as many requests as you want. Therefore,
1283	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1565	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1284	as a stop gap to shield against fatal memory overflow (with large values).	1566	as a stop gap to shield against fatal memory overflow (with large values).
1285		1567
1286	=back	1568	=back
1287		1569
1288	=head3 STATISTICAL INFORMATION	1570	=head3 STATISTICAL INFORMATION
…		…
1309	Returns the number of requests currently in the pending state (executed,	1591	Returns the number of requests currently in the pending state (executed,
1310	but not yet processed by poll_cb).	1592	but not yet processed by poll_cb).
1311		1593
1312	=back	1594	=back
1313		1595
		1596	=head3 MISCELLANEOUS FUNCTIONS
		1597
		1598	IO::AIO implements some functions that might be useful, but are not
		1599	asynchronous.
		1600
		1601	=over 4
		1602
		1603	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1604
		1605	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1606	but is blocking (this makes most sense if you know the input data is
		1607	likely cached already and the output filehandle is set to non-blocking
		1608	operations).
		1609
		1610	Returns the number of bytes copied, or C<-1> on error.
		1611
		1612	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1613
		1614	Simply calls the C<posix_fadvise> function (see its
		1615	manpage for details). The following advice constants are
		1616	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1617	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1618	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1619
		1620	On systems that do not implement C<posix_fadvise>, this function returns
		1621	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1622
		1623	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1624
		1625	Simply calls the C<posix_madvise> function (see its
		1626	manpage for details). The following advice constants are
		1627	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1628	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1629
		1630	On systems that do not implement C<posix_madvise>, this function returns
		1631	ENOSYS, otherwise the return value of C<posix_madvise>.
		1632
		1633	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1634
		1635	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1636	$scalar (see its manpage for details). The following protect
		1637	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1638	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1639
		1640	On systems that do not implement C<mprotect>, this function returns
		1641	ENOSYS, otherwise the return value of C<mprotect>.
		1642
		1643	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1644
		1645	Memory-maps a file (or anonymous memory range) and attaches it to the
		1646	given C<$scalar>, which will act like a string scalar.
		1647
		1648	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1649	change the string length, and most read-only operations such as copying it
		1650	or searching it with regexes and so on.
		1651
		1652	Anything else is unsafe and will, at best, result in memory leaks.
		1653
		1654	The memory map associated with the C<$scalar> is automatically removed
		1655	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1656	C<IO::AIO::munmap> functions are called.
		1657
		1658	This calls the C<mmap>(2) function internally. See your system's manual
		1659	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1660
		1661	The C<$length> must be larger than zero and smaller than the actual
		1662	filesize.
		1663
		1664	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1665	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1666
		1667	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1668	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1669	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1670	(which is set to C<MAP_ANON> if your system only provides this
		1671	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1672	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1673	C<IO::AIO::MAP_NONBLOCK>
		1674
		1675	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1676
		1677	C<$offset> is the offset from the start of the file - it generally must be
		1678	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1679
		1680	Example:
		1681
		1682	use Digest::MD5;
		1683	use IO::AIO;
		1684
		1685	open my $fh, "<verybigfile"
		1686	or die "$!";
		1687
		1688	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1689	or die "verybigfile: $!";
		1690
		1691	my $fast_md5 = md5 $data;
		1692
		1693	=item IO::AIO::munmap $scalar
		1694
		1695	Removes a previous mmap and undefines the C<$scalar>.
		1696
		1697	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1698
		1699	Calls the C<munlock> function, undoing the effects of a previous
		1700	C<aio_mlock> call (see its description for details).
		1701
		1702	=item IO::AIO::munlockall
		1703
		1704	Calls the C<munlockall> function.
		1705
		1706	On systems that do not implement C<munlockall>, this function returns
		1707	ENOSYS, otherwise the return value of C<munlockall>.
		1708
		1709	=back
		1710
1314	=cut	1711	=cut
1315		1712
1316	min_parallel 8;	1713	min_parallel 8;
1317		1714
1318	END { flush }	1715	END { flush }
1319		1716
1320	1;	1717	1;
		1718
		1719	=head1 EVENT LOOP INTEGRATION
		1720
		1721	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1722	automatically into many event loops:
		1723
		1724	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1725	use AnyEvent::AIO;
		1726
		1727	You can also integrate IO::AIO manually into many event loops, here are
		1728	some examples of how to do this:
		1729
		1730	# EV integration
		1731	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1732
		1733	# Event integration
		1734	Event->io (fd => IO::AIO::poll_fileno,
		1735	poll => 'r',
		1736	cb => \&IO::AIO::poll_cb);
		1737
		1738	# Glib/Gtk2 integration
		1739	add_watch Glib::IO IO::AIO::poll_fileno,
		1740	in => sub { IO::AIO::poll_cb; 1 };
		1741
		1742	# Tk integration
		1743	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1744	readable => \&IO::AIO::poll_cb);
		1745
		1746	# Danga::Socket integration
		1747	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1748	\&IO::AIO::poll_cb);
1321		1749
1322	=head2 FORK BEHAVIOUR	1750	=head2 FORK BEHAVIOUR
1323		1751
1324	This module should do "the right thing" when the process using it forks:	1752	This module should do "the right thing" when the process using it forks:
1325		1753
…		…
1358		1786
1359	Known bugs will be fixed in the next release.	1787	Known bugs will be fixed in the next release.
1360		1788
1361	=head1 SEE ALSO	1789	=head1 SEE ALSO
1362		1790
1363	L<Coro::AIO>.	1791	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1792	more natural syntax.
1364		1793
1365	=head1 AUTHOR	1794	=head1 AUTHOR
1366		1795
1367	Marc Lehmann <schmorp@schmorp.de>	1796	Marc Lehmann <schmorp@schmorp.de>
1368	http://home.schmorp.de/	1797	http://home.schmorp.de/

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