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Revision 1.108 by root, Fri Jun 1 13:25:50 2007 UTC vs.
Revision 1.193 by root, Thu May 26 04:15:37 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
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51
52	=head1 DESCRIPTION	31	=head1 DESCRIPTION
53		32
54	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
55	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
56		36
57	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
58	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
59	will still block, but you can do something else in the meantime. This	39	will still block, but you can do something else in the meantime. This
60	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
64	on a RAID volume or over NFS when you do a number of stat operations	44	on a RAID volume or over NFS when you do a number of stat operations
65	concurrently.	45	concurrently.
66		46
67	While most of this works on all types of file descriptors (for	47	While most of this works on all types of file descriptors (for
68	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
69	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
70	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>
71	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.
72		52
73	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
74	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
75	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
…		…
85	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
86	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
87		67
88	=head2 EXAMPLE	68	=head2 EXAMPLE
89		69
90	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
91	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
92		72
93	use Fcntl;	73	use Fcntl;
94	use Event;	74	use EV;
95	use IO::AIO;	75	use IO::AIO;
96		76
97	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
98	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
99	poll => 'r',
100	cb => \&IO::AIO::poll_cb);
101		79
102	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
103	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
104	my $fh = shift	82	my $fh = shift
105	or die "error while opening: $!";	83	or die "error while opening: $!";
106		84
107	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
108	my $size = -s $fh;	86	my $size = -s $fh;
…		…
117		95
118	# file contents now in $contents	96	# file contents now in $contents
119	print $contents;	97	print $contents;
120		98
121	# exit event loop and program	99	# exit event loop and program
122	Event::unloop;	100	EV::unloop;
123	};	101	};
124	};	102	};
125		103
126	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
127	# check for sockets etc. etc.	105	# check for sockets etc. etc.
128		106
129	# process events as long as there are some:	107	# process events as long as there are some:
130	Event::loop;	108	EV::loop;
131		109
132	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
133		111
134	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
135	directly visible to Perl.	113	directly visible to Perl.
…		…
183		161
184	=cut	162	=cut
185		163
186	package IO::AIO;	164	package IO::AIO;
187		165
188	no warnings;	166	use Carp ();
189	use strict 'vars';	167
		168	use common::sense;
190		169
191	use base 'Exporter';	170	use base 'Exporter';
192		171
193	BEGIN {	172	BEGIN {
194	our $VERSION = '2.4';	173	our $VERSION = '3.8';
195		174
196	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
197	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
198	aio_readlink 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
199	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
200	aio_chown aio_chmod aio_utime);	181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs);
		184
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle idle_timeout
204	nreqs nready npending nthreads	188	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	189	max_poll_time max_poll_reqs
		190	sendfile fadvise madvise
		191	mmap munmap munlock munlockall);
		192
		193	push @AIO_REQ, qw(aio_busy); # not exported
206		194
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		196
209	require XSLoader;	197	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
211	}	199	}
212		200
213	=head1 FUNCTIONS	201	=head1 FUNCTIONS
		202
		203	=head2 QUICK OVERVIEW
		204
		205	This section simply lists the prototypes of the most important functions
		206	for quick reference. See the following sections for function-by-function
		207	documentation.
		208
		209	aio_open $pathname, $flags, $mode, $callback->($fh)
		210	aio_close $fh, $callback->($status)
		211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		214	aio_readahead $fh,$offset,$length, $callback->($retval)
		215	aio_stat $fh_or_path, $callback->($status)
		216	aio_lstat $fh, $callback->($status)
		217	aio_statvfs $fh_or_path, $callback->($statvfs)
		218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		220	aio_truncate $fh_or_path, $offset, $callback->($status)
		221	aio_chmod $fh_or_path, $mode, $callback->($status)
		222	aio_unlink $pathname, $callback->($status)
		223	aio_mknod $path, $mode, $dev, $callback->($status)
		224	aio_link $srcpath, $dstpath, $callback->($status)
		225	aio_symlink $srcpath, $dstpath, $callback->($status)
		226	aio_readlink $path, $callback->($link)
		227	aio_rename $srcpath, $dstpath, $callback->($status)
		228	aio_mkdir $pathname, $mode, $callback->($status)
		229	aio_rmdir $pathname, $callback->($status)
		230	aio_readdir $pathname, $callback->($entries)
		231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		234	aio_load $path, $data, $callback->($status)
		235	aio_copy $srcpath, $dstpath, $callback->($status)
		236	aio_move $srcpath, $dstpath, $callback->($status)
		237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		238	aio_rmtree $path, $callback->($status)
		239	aio_sync $callback->($status)
		240	aio_fsync $fh, $callback->($status)
		241	aio_fdatasync $fh, $callback->($status)
		242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		243	aio_pathsync $path, $callback->($status)
		244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		247	aio_mlockall $flags, $callback->($status)
		248	aio_group $callback->(...)
		249	aio_nop $callback->()
		250
		251	$prev_pri = aioreq_pri [$pri]
		252	aioreq_nice $pri_adjust
		253
		254	IO::AIO::poll_wait
		255	IO::AIO::poll_cb
		256	IO::AIO::poll
		257	IO::AIO::flush
		258	IO::AIO::max_poll_reqs $nreqs
		259	IO::AIO::max_poll_time $seconds
		260	IO::AIO::min_parallel $nthreads
		261	IO::AIO::max_parallel $nthreads
		262	IO::AIO::max_idle $nthreads
		263	IO::AIO::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, $length = undef
		274	IO::AIO::munlockall
214		275
215	=head2 AIO REQUEST FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
216		277
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	280	and they all accept an additional (and optional) C<$callback> argument
220	which must be a code reference. This code reference will get called with	281	which must be a code reference. This code reference will get called with
221	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	282	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
222	perl, which usually delivers "false") as it's sole argument when the given	283	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	284	syscall has been executed asynchronously.
224		285
225	All functions expecting a filehandle keep a copy of the filehandle	286	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	287	internally until the request has finished.
227		288
…		…
241	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
242	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)
243	use something else to ensure your scalar has the correct contents.	304	use something else to ensure your scalar has the correct contents.
244		305
245	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
246	handles correctly wether it is set or not.	307	handles correctly whether it is set or not.
247		308
248	=over 4	309	=over 4
249		310
250	=item $prev_pri = aioreq_pri [$pri]	311	=item $prev_pri = aioreq_pri [$pri]
251		312
…		…
298	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
299	change the umask.	360	change the umask.
300		361
301	Example:	362	Example:
302		363
303	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
304	if ($_[0]) {	365	if ($_[0]) {
305	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
306	...	367	...
307	} else {	368	} else {
308	die "open failed: $!\n";	369	die "open failed: $!\n";
…		…
311		372
312		373
313	=item aio_close $fh, $callback->($status)	374	=item aio_close $fh, $callback->($status)
314		375
315	Asynchronously close a file and call the callback with the result	376	Asynchronously close a file and call the callback with the result
316	code. I<WARNING:> although accepted, you should not pass in a perl	377	code.
317	filehandle here, as perl will likely close the file descriptor another
318	time when the filehandle is destroyed. Normally, you can safely call perls
319	C<close> or just let filehandles go out of scope.
320		378
321	This is supposed to be a bug in the API, so that might change. It's	379	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
322	therefore best to avoid this function.	380	closing the file descriptor associated with the filehandle itself.
323		381
		382	Therefore, C<aio_close> will not close the filehandle - instead it will
		383	use dup2 to overwrite the file descriptor with the write-end of a pipe
		384	(the pipe fd will be created on demand and will be cached).
		385
		386	Or in other words: the file descriptor will be closed, but it will not be
		387	free for reuse until the perl filehandle is closed.
		388
		389	=cut
324		390
325	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	391	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
326		392
327	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	393	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
328		394
329	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
330	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<$dataoffset>
331	callback without the actual number of bytes read (or -1 on error, just	397	and calls the callback without the actual number of bytes read (or -1 on
		398	error, just like the syscall).
		399
		400	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		401	offset plus the actual number of bytes read.
		402
332	like the syscall). If C<offset> is undefined, then the current file offset	403	If C<$offset> is undefined, then the current file descriptor offset will
333	will be used (and updated), otherwise the file offset will not be changed	404	be used (and updated), otherwise the file descriptor offset will not be
334	by these calls.	405	changed by these calls.
		406
		407	If C<$length> is undefined in C<aio_write>, use the remaining length of
		408	C<$data>.
		409
		410	If C<$dataoffset> is less than zero, it will be counted from the end of
		411	C<$data>.
335		412
336	The C<$data> scalar I<MUST NOT> be modified in any way while the request	413	The C<$data> scalar I<MUST NOT> be modified in any way while the request
337	is outstanding. Modifying it can result in segfaults or World War III (if	414	is outstanding. Modifying it can result in segfaults or World War III (if
338	the necessary/optional hardware is installed).	415	the necessary/optional hardware is installed).
339		416
…		…
352	reading at byte offset C<$in_offset>, and starts writing at the current	429	reading at byte offset C<$in_offset>, and starts writing at the current
353	file offset of C<$out_fh>. Because of that, it is not safe to issue more	430	file offset of C<$out_fh>. Because of that, it is not safe to issue more
354	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	431	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
355	other.	432	other.
356		433
		434	Please note that C<aio_sendfile> can read more bytes from C<$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
357	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
358	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
359	socket, and C<$in_fh> should refer to mmap'able file.	452	socket, and C<$in_fh> should refer to an mmap'able file.
360		453
361	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>,
362	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
363	regardless of the limitations of the operating system.	457	filehandle regardless of the limitations of the operating system.
364
365	Please note, however, that C<aio_sendfile> can read more bytes from
366	C<$in_fh> than are written, and there is no way to find out how many
367	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
368	provides the number of bytes written to C<$out_fh>. Only if the result
369	value equals C<$length> one can assume that C<$length> bytes have been
370	read.
371		458
372		459
373	=item aio_readahead $fh,$offset,$length, $callback->($retval)	460	=item aio_readahead $fh,$offset,$length, $callback->($retval)
374		461
375	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
…		…
398		485
399	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
400	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
401	unless perl itself is compiled with large file support.	488	unless perl itself is compiled with large file support.
402		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
403	Example: Print the length of F</etc/passwd>:	499	Example: Print the length of F</etc/passwd>:
404		500
405	aio_stat "/etc/passwd", sub {	501	aio_stat "/etc/passwd", sub {
406	$_[0] and die "stat failed: $!";	502	$_[0] and die "stat failed: $!";
407	print "size is ", -s _, "\n";	503	print "size is ", -s _, "\n";
408	};	504	};
409		505
410		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
411	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	552	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
412		553
413	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
414	and $mtime being undef). Fractional times are supported if the underlying	555	and $mtime being undef). Fractional times are supported if the underlying
415	syscalls support them.	556	syscalls support them.
…		…
437	aio_chown "path", 0, -1;	578	aio_chown "path", 0, -1;
438	# same as above:	579	# same as above:
439	aio_chown "path", 0, undef;	580	aio_chown "path", 0, undef;
440		581
441		582
		583	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		584
		585	Works like truncate(2) or ftruncate(2).
		586
		587
442	=item aio_chmod $fh_or_path, $mode, $callback->($status)	588	=item aio_chmod $fh_or_path, $mode, $callback->($status)
443		589
444	Works like perl's C<chmod> function.	590	Works like perl's C<chmod> function.
445		591
446		592
…		…
458		604
459	The only (POSIX-) portable way of calling this function is:	605	The only (POSIX-) portable way of calling this function is:
460		606
461	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	607	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
462		608
		609	See C<aio_stat> for info about some potentially helpful extra constants
		610	and functions.
463		611
464	=item aio_link $srcpath, $dstpath, $callback->($status)	612	=item aio_link $srcpath, $dstpath, $callback->($status)
465		613
466	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
467	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.
…		…
503		651
504	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
505	directory (i.e. opendir + readdir + closedir). The entries will not be	653	directory (i.e. opendir + readdir + closedir). The entries will not be
506	sorted, and will B<NOT> include the C<.> and C<..> entries.	654	sorted, and will B<NOT> include the C<.> and C<..> entries.
507		655
508	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
509	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<$entries> will be
		664	C<undef>.
		665
		666	The flags are a combination of the following constants, ORed together (the
		667	flags will also be passed to the callback, possibly modified):
		668
		669	=over 4
		670
		671	=item IO::AIO::READDIR_DENTS
		672
		673	When this flag is off, then the callback gets an arrayref consisting of
		674	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		675	C<[$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<$inode> is the inode number (which might not be exact on systems with 64
		691	bit inode numbers and 32 bit perls). This field has unspecified content on
		692	systems that do not deliver the inode information.
		693
		694	=item IO::AIO::READDIR_DIRS_FIRST
		695
		696	When this flag is set, then the names will be returned in an order where
		697	likely directories come first, in optimal stat order. This is useful when
		698	you need to quickly find directories, or you want to find all directories
		699	while avoiding to stat() each entry.
		700
		701	If the system returns type information in readdir, then this is used
		702	to find directories directly. Otherwise, likely directories are names
		703	beginning with ".", or otherwise names with no dots, of which names with
		704	short names are tried first.
		705
		706	=item IO::AIO::READDIR_STAT_ORDER
		707
		708	When this flag is set, then the names will be returned in an order
		709	suitable for stat()'ing each one. That is, when you plan to stat()
		710	all files in the given directory, then the returned order will likely
		711	be fastest.
		712
		713	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		714	the likely dirs come first, resulting in a less optimal stat order.
		715
		716	=item IO::AIO::READDIR_FOUND_UNKNOWN
		717
		718	This flag should not be set when calling C<aio_readdirx>. Instead, it
		719	is being set by C<aio_readdirx>, when any of the C<$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
510		724
511		725
512	=item aio_load $path, $data, $callback->($status)	726	=item aio_load $path, $data, $callback->($status)
513		727
514	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
515	memory. Status is the same as with aio_read.	729	memory. Status is the same as with aio_read.
516		730
517	=cut	731	=cut
518		732
519	sub aio_load($$;$) {	733	sub aio_load($$;$) {
520	aio_block {
521	my ($path, undef, $cb) = @_;	734	my ($path, undef, $cb) = @_;
522	my $data = \$_[1];	735	my $data = \$_[1];
523		736
524	my $pri = aioreq_pri;	737	my $pri = aioreq_pri;
525	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);
526		744
527	aioreq_pri $pri;	745	aioreq_pri $pri;
528	add $grp aio_open $path, O_RDONLY, 0, sub {
529	my $fh = shift
530	or return $grp->result (-1);
531
532	aioreq_pri $pri;
533	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	746	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
534	$grp->result ($_[0]);	747	$grp->result ($_[0]);
535	};
536	};	748	};
537
538	$grp
539	}	749	};
		750
		751	$grp
540	}	752	}
541		753
542	=item aio_copy $srcpath, $dstpath, $callback->($status)	754	=item aio_copy $srcpath, $dstpath, $callback->($status)
543		755
544	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
545	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
546	the C<0> (error) or C<-1> ok.	758	a status of C<0> (ok) or C<-1> (error, see C<$!>).
547		759
548	This is a composite request that it creates the destination file with	760	This is a composite request that creates the destination file with
549	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
550	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	762	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
551	uid/gid, in that order.	763	uid/gid, in that order.
552		764
553	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
…		…
555	errors are being ignored.	767	errors are being ignored.
556		768
557	=cut	769	=cut
558		770
559	sub aio_copy($$;$) {	771	sub aio_copy($$;$) {
560	aio_block {
561	my ($src, $dst, $cb) = @_;	772	my ($src, $dst, $cb) = @_;
562		773
563	my $pri = aioreq_pri;	774	my $pri = aioreq_pri;
564	my $grp = aio_group $cb;	775	my $grp = aio_group $cb;
565		776
566	aioreq_pri $pri;	777	aioreq_pri $pri;
567	add $grp aio_open $src, O_RDONLY, 0, sub {	778	add $grp aio_open $src, O_RDONLY, 0, sub {
568	if (my $src_fh = $_[0]) {	779	if (my $src_fh = $_[0]) {
569	my @stat = stat $src_fh;	780	my @stat = stat $src_fh; # hmm, might block over nfs?
570		781
571	aioreq_pri $pri;	782	aioreq_pri $pri;
572	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 {
573	if (my $dst_fh = $_[0]) {	784	if (my $dst_fh = $_[0]) {
574	aioreq_pri $pri;	785	aioreq_pri $pri;
575	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	786	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
576	if ($_[0] == $stat[7]) {	787	if ($_[0] == $stat[7]) {
577	$grp->result (0);	788	$grp->result (0);
578	close $src_fh;	789	close $src_fh;
579		790
580	# those should not normally block. should. should.
581	utime $stat[8], $stat[9], $dst;
582	chmod $stat[2] & 07777, $dst_fh;
583	chown $stat[4], $stat[5], $dst_fh;
584	close $dst_fh;
585	} else {	791	my $ch = sub {
586	$grp->result (-1);
587	close $src_fh;
588	close $dst_fh;
589
590	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;
591	add $grp aio_unlink $dst;	797	add $grp aio_close $dst_fh;
		798	}
		799	};
592	}	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;
593	};	818	}
594	} else {
595	$grp->result (-1);
596	}	819	};
		820	} else {
		821	$grp->result (-1);
597	},	822	}
598
599	} else {
600	$grp->result (-1);
601	}	823	},
		824
		825	} else {
		826	$grp->result (-1);
602	};	827	}
603
604	$grp
605	}	828	};
		829
		830	$grp
606	}	831	}
607		832
608	=item aio_move $srcpath, $dstpath, $callback->($status)	833	=item aio_move $srcpath, $dstpath, $callback->($status)
609		834
610	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
611	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
612	the C<0> (error) or C<-1> ok.	837	a status of C<0> (ok) or C<-1> (error, see C<$!>).
613		838
614	This is a composite request that tries to rename(2) the file first. If	839	This is a composite request that tries to rename(2) the file first; if
615	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	840	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
616	that is successful, unlinking the C<$srcpath>.	841	that is successful, unlinks the C<$srcpath>.
617		842
618	=cut	843	=cut
619		844
620	sub aio_move($$;$) {	845	sub aio_move($$;$) {
621	aio_block {
622	my ($src, $dst, $cb) = @_;	846	my ($src, $dst, $cb) = @_;
623		847
624	my $pri = aioreq_pri;	848	my $pri = aioreq_pri;
625	my $grp = aio_group $cb;	849	my $grp = aio_group $cb;
626		850
627	aioreq_pri $pri;	851	aioreq_pri $pri;
628	add $grp aio_rename $src, $dst, sub {	852	add $grp aio_rename $src, $dst, sub {
629	if ($_[0] && $! == EXDEV) {	853	if ($_[0] && $! == EXDEV) {
630	aioreq_pri $pri;	854	aioreq_pri $pri;
631	add $grp aio_copy $src, $dst, sub {	855	add $grp aio_copy $src, $dst, sub {
632	$grp->result ($_[0]);
633
634	if (!$_[0]) {
635	aioreq_pri $pri;
636	add $grp aio_unlink $src;
637	}
638	};
639	} else {
640	$grp->result ($_[0]);	856	$grp->result ($_[0]);
		857
		858	if (!$_[0]) {
		859	aioreq_pri $pri;
		860	add $grp aio_unlink $src;
		861	}
641	}	862	};
		863	} else {
		864	$grp->result ($_[0]);
642	};	865	}
643
644	$grp
645	}	866	};
		867
		868	$grp
646	}	869	}
647		870
648	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	871	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
649		872
650	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
…		…
670		893
671	Implementation notes.	894	Implementation notes.
672		895
673	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.
674		897
		898	If readdir returns file type information, then this is used directly to
		899	find directories.
		900
675	After reading the directory, the modification time, size etc. of the	901	Otherwise, after reading the directory, the modification time, size etc.
676	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
677	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
678	entries are directories (if >= 2). Otherwise, no knowledge of the number	904	how many entries are directories (if >= 2). Otherwise, no knowledge of the
679	of subdirectories will be assumed.	905	number of subdirectories will be assumed.
680		906
681	Then entries will be sorted into likely directories (everything without	907	Then entries will be sorted into likely directories a non-initial dot
682	a non-initial dot currently) and likely non-directories (everything	908	currently) and likely non-directories (see C<aio_readdirx>). Then every
683	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,
684	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
685	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
686	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
687	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
688	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.
689		916
690	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
691	rest of the entries is assumed to be non-directories.	918	rest of the entries is assumed to be non-directories.
692		919
693	This only works with certainty on POSIX (= UNIX) filesystems, which	920	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
698	directory counting heuristic.	925	directory counting heuristic.
699		926
700	=cut	927	=cut
701		928
702	sub aio_scandir($$;$) {	929	sub aio_scandir($$;$) {
703	aio_block {
704	my ($path, $maxreq, $cb) = @_;	930	my ($path, $maxreq, $cb) = @_;
705		931
706	my $pri = aioreq_pri;	932	my $pri = aioreq_pri;
707		933
708	my $grp = aio_group $cb;	934	my $grp = aio_group $cb;
709		935
710	$maxreq = 4 if $maxreq <= 0;	936	$maxreq = 4 if $maxreq <= 0;
711		937
712	# 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
713	aioreq_pri $pri;	946	aioreq_pri $pri;
714	add $grp aio_stat $path, sub {	947	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		948	my $entries = shift
715	return $grp->result () if $_[0];	949	or return $grp->result ();
716	my $now = time;
717	my $hash1 = join ":", (stat _)[0,1,3,7,9];
718		950
719	# read the directory entries	951	# stat the dir another time
720	aioreq_pri $pri;	952	aioreq_pri $pri;
721	add $grp aio_readdir $path, sub {
722	my $entries = shift
723	or return $grp->result ();
724
725	# stat the dir another time
726	aioreq_pri $pri;
727	add $grp aio_stat $path, sub {	953	add $grp aio_stat $path, sub {
728	my $hash2 = join ":", (stat _)[0,1,3,7,9];	954	my $hash2 = join ":", (stat _)[0,1,3,7,9];
729		955
730	my $ndirs;	956	my $ndirs;
731		957
732	# take the slow route if anything looks fishy	958	# take the slow route if anything looks fishy
733	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	959	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
734	$ndirs = -1;	960	$ndirs = -1;
735	} else {	961	} else {
736	# if nlink == 2, we are finished	962	# if nlink == 2, we are finished
737	# on non-posix-fs's, we rely on nlink < 2	963	# for non-posix-fs's, we rely on nlink < 2
738	$ndirs = (stat _)[3] - 2	964	$ndirs = (stat _)[3] - 2
739	or return $grp->result ([], $entries);	965	or return $grp->result ([], $entries);
740	}	966	}
741		967
742	# sort into likely dirs and likely nondirs
743	# dirs == files without ".", short entries first
744	$entries = [map $_->[0],
745	sort { $b->[1] cmp $a->[1] }
746	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
747	@$entries];
748
749	my (@dirs, @nondirs);	968	my (@dirs, @nondirs);
750		969
751	my $statgrp = add $grp aio_group sub {	970	my $statgrp = add $grp aio_group sub {
752	$grp->result (\@dirs, \@nondirs);	971	$grp->result (\@dirs, \@nondirs);
753	};	972	};
754		973
755	limit $statgrp $maxreq;	974	limit $statgrp $maxreq;
756	feed $statgrp sub {	975	feed $statgrp sub {
757	return unless @$entries;	976	return unless @$entries;
758	my $entry = pop @$entries;	977	my $entry = shift @$entries;
759		978
760	aioreq_pri $pri;	979	aioreq_pri $pri;
761	add $statgrp aio_stat "$path/$entry/.", sub {	980	add $statgrp aio_stat "$path/$entry/.", sub {
762	if ($_[0] < 0) {	981	if ($_[0] < 0) {
763	push @nondirs, $entry;	982	push @nondirs, $entry;
764	} else {	983	} else {
765	# need to check for real directory	984	# need to check for real directory
766	aioreq_pri $pri;	985	aioreq_pri $pri;
767	add $statgrp aio_lstat "$path/$entry", sub {	986	add $statgrp aio_lstat "$path/$entry", sub {
768	if (-d _) {	987	if (-d _) {
769	push @dirs, $entry;	988	push @dirs, $entry;
770		989
771	unless (--$ndirs) {	990	unless (--$ndirs) {
772	push @nondirs, @$entries;	991	push @nondirs, @$entries;
773	feed $statgrp;	992	feed $statgrp;
774	}
775	} else {
776	push @nondirs, $entry;
777	}	993	}
		994	} else {
		995	push @nondirs, $entry;
778	}	996	}
779	}	997	}
780	};	998	}
781	};	999	};
782	};	1000	};
783	};	1001	};
784	};	1002	};
785
786	$grp
787	}	1003	};
		1004
		1005	$grp
788	}	1006	}
789		1007
790	=item aio_rmtree $path, $callback->($status)	1008	=item aio_rmtree $path, $callback->($status)
791		1009
792	Delete a directory tree starting (and including) C<$path>, return the	1010	Delete a directory tree starting (and including) C<$path>, return the
…		…
796		1014
797	=cut	1015	=cut
798		1016
799	sub aio_rmtree;	1017	sub aio_rmtree;
800	sub aio_rmtree($;$) {	1018	sub aio_rmtree($;$) {
801	aio_block {
802	my ($path, $cb) = @_;	1019	my ($path, $cb) = @_;
803		1020
804	my $pri = aioreq_pri;	1021	my $pri = aioreq_pri;
805	my $grp = aio_group $cb;	1022	my $grp = aio_group $cb;
806		1023
807	aioreq_pri $pri;	1024	aioreq_pri $pri;
808	add $grp aio_scandir $path, 0, sub {	1025	add $grp aio_scandir $path, 0, sub {
809	my ($dirs, $nondirs) = @_;	1026	my ($dirs, $nondirs) = @_;
810		1027
811	my $dirgrp = aio_group sub {	1028	my $dirgrp = aio_group sub {
812	add $grp aio_rmdir $path, sub {	1029	add $grp aio_rmdir $path, sub {
813	$grp->result ($_[0]);	1030	$grp->result ($_[0]);
814	};
815	};	1031	};
816
817	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
818	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
819
820	add $grp $dirgrp;
821	};	1032	};
822		1033
823	$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;
824	}	1038	};
		1039
		1040	$grp
825	}	1041	}
		1042
		1043	=item aio_sync $callback->($status)
		1044
		1045	Asynchronously call sync and call the callback when finished.
826		1046
827	=item aio_fsync $fh, $callback->($status)	1047	=item aio_fsync $fh, $callback->($status)
828		1048
829	Asynchronously call fsync on the given filehandle and call the callback	1049	Asynchronously call fsync on the given filehandle and call the callback
830	with the fsync result code.	1050	with the fsync result code.
…		…
834	Asynchronously call fdatasync on the given filehandle and call the	1054	Asynchronously call fdatasync on the given filehandle and call the
835	callback with the fdatasync result code.	1055	callback with the fdatasync result code.
836		1056
837	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
838	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;
839		1178
840	=item aio_group $callback->(...)	1179	=item aio_group $callback->(...)
841		1180
842	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
843	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
…		…
893	=item cancel $req	1232	=item cancel $req
894		1233
895	Cancels the request, if possible. Has the effect of skipping execution	1234	Cancels the request, if possible. Has the effect of skipping execution
896	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
897	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
898	untouched. That means that requests that currently execute will not be	1237	untouched (with the exception of readdir). That means that requests that
899	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.
900		1240
901	=item cb $req $callback->(...)	1241	=item cb $req $callback->(...)
902		1242
903	Replace (or simply set) the callback registered to the request.	1243	Replace (or simply set) the callback registered to the request.
904		1244
…		…
955	Their lifetime, simplified, looks like this: when they are empty, they	1295	Their lifetime, simplified, looks like this: when they are empty, they
956	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
957	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
958	exist.	1298	exist.
959		1299
960	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
961	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
962	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
963	itself finish.	1303	further requests to the group. And only when all those requests have
		1304	finished will the the group itself finish.
964		1305
965	=over 4	1306	=over 4
966		1307
967	=item add $grp ...	1308	=item add $grp ...
968		1309
…		…
977	=item $grp->cancel_subs	1318	=item $grp->cancel_subs
978		1319
979	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
980	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.
981		1322
		1323	The group request will finish normally (you cannot add requests to the
		1324	group).
		1325
982	=item $grp->result (...)	1326	=item $grp->result (...)
983		1327
984	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
985	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
986	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,
987	no argument will be passed and errno is zero.	1331	no argument will be passed and errno is zero.
988		1332
989	=item $grp->errno ([$errno])	1333	=item $grp->errno ([$errno])
990		1334
…		…
1001	=item feed $grp $callback->($grp)	1345	=item feed $grp $callback->($grp)
1002		1346
1003	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
1004	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,
1005	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,
1006	this might starve other requests for a potentially long time. For	1350	this might starve other requests for a potentially long time. For example,
1007	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,
1008	requests, delaying any later requests for a long time.	1352	delaying any later requests for a long time.
1009		1353
1010	To avoid this, and allow incremental generation of requests, you can	1354	To avoid this, and allow incremental generation of requests, you can
1011	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
1012	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>,
1013	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
…		…
1017	not impose any limits).	1361	not impose any limits).
1018		1362
1019	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
1020	automatically removed from the group.	1364	automatically removed from the group.
1021		1365
1022	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.
1023		1368
1024	Example:	1369	Example:
1025		1370
1026	# 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:
1027		1372
…		…
1039	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
1040	the group contains less than this many requests.	1385	the group contains less than this many requests.
1041		1386
1042	Setting the limit to C<0> will pause the feeding process.	1387	Setting the limit to C<0> will pause the feeding process.
1043		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
1044	=back	1392	=back
1045		1393
1046	=head2 SUPPORT FUNCTIONS	1394	=head2 SUPPORT FUNCTIONS
1047		1395
1048	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1396	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1050	=over 4	1398	=over 4
1051		1399
1052	=item $fileno = IO::AIO::poll_fileno	1400	=item $fileno = IO::AIO::poll_fileno
1053		1401
1054	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
1055	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,
1056	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
1057	to call C<poll_cb> to check the results.	1405	you have to call C<poll_cb> to check the results.
1058		1406
1059	See C<poll_cb> for an example.	1407	See C<poll_cb> for an example.
1060		1408
1061	=item IO::AIO::poll_cb	1409	=item IO::AIO::poll_cb
1062		1410
1063	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
1064	regularly. Returns the number of events processed. Returns immediately	1412	this regularly. Returns C<0> if all events could be processed (or there
1065	when no events are outstanding. The amount of events processed depends on	1413	were no events to process), or C<-1> if it returned earlier for whatever
1066	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1414	reason. Returns immediately when no events are outstanding. The amount of
		1415	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1416	C<IO::AIO::max_poll_time>.
1067		1417
1068	If not all requests were processed for whatever reason, the filehandle	1418	If not all requests were processed for whatever reason, the filehandle
1069	will still be ready when C<poll_cb> returns.	1419	will still be ready when C<poll_cb> returns, so normally you don't have to
		1420	do anything special to have it called later.
		1421
		1422	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1423	ready, it can be beneficial to call this function from loops which submit
		1424	a lot of requests, to make sure the results get processed when they become
		1425	available and not just when the loop is finished and the event loop takes
		1426	over again. This function returns very fast when there are no outstanding
		1427	requests.
1070		1428
1071	Example: Install an Event watcher that automatically calls	1429	Example: Install an Event watcher that automatically calls
1072	IO::AIO::poll_cb with high priority:	1430	IO::AIO::poll_cb with high priority (more examples can be found in the
		1431	SYNOPSIS section, at the top of this document):
1073		1432
1074	Event->io (fd => IO::AIO::poll_fileno,	1433	Event->io (fd => IO::AIO::poll_fileno,
1075	poll => 'r', async => 1,	1434	poll => 'r', async => 1,
1076	cb => \&IO::AIO::poll_cb);	1435	cb => \&IO::AIO::poll_cb);
		1436
		1437	=item IO::AIO::poll_wait
		1438
		1439	If there are any outstanding requests and none of them in the result
		1440	phase, wait till the result filehandle becomes ready for reading (simply
		1441	does a C<select> on the filehandle. This is useful if you want to
		1442	synchronously wait for some requests to finish).
		1443
		1444	See C<nreqs> for an example.
		1445
		1446	=item IO::AIO::poll
		1447
		1448	Waits until some requests have been handled.
		1449
		1450	Returns the number of requests processed, but is otherwise strictly
		1451	equivalent to:
		1452
		1453	IO::AIO::poll_wait, IO::AIO::poll_cb
		1454
		1455	=item IO::AIO::flush
		1456
		1457	Wait till all outstanding AIO requests have been handled.
		1458
		1459	Strictly equivalent to:
		1460
		1461	IO::AIO::poll_wait, IO::AIO::poll_cb
		1462	while IO::AIO::nreqs;
1077		1463
1078	=item IO::AIO::max_poll_reqs $nreqs	1464	=item IO::AIO::max_poll_reqs $nreqs
1079		1465
1080	=item IO::AIO::max_poll_time $seconds	1466	=item IO::AIO::max_poll_time $seconds
1081		1467
…		…
1106	# use a low priority so other tasks have priority	1492	# use a low priority so other tasks have priority
1107	Event->io (fd => IO::AIO::poll_fileno,	1493	Event->io (fd => IO::AIO::poll_fileno,
1108	poll => 'r', nice => 1,	1494	poll => 'r', nice => 1,
1109	cb => &IO::AIO::poll_cb);	1495	cb => &IO::AIO::poll_cb);
1110		1496
1111	=item IO::AIO::poll_wait
1112
1113	If there are any outstanding requests and none of them in the result
1114	phase, wait till the result filehandle becomes ready for reading (simply
1115	does a C<select> on the filehandle. This is useful if you want to
1116	synchronously wait for some requests to finish).
1117
1118	See C<nreqs> for an example.
1119
1120	=item IO::AIO::poll
1121
1122	Waits until some requests have been handled.
1123
1124	Returns the number of requests processed, but is otherwise strictly
1125	equivalent to:
1126
1127	IO::AIO::poll_wait, IO::AIO::poll_cb
1128
1129	=item IO::AIO::flush
1130
1131	Wait till all outstanding AIO requests have been handled.
1132
1133	Strictly equivalent to:
1134
1135	IO::AIO::poll_wait, IO::AIO::poll_cb
1136	while IO::AIO::nreqs;
1137
1138	=back	1497	=back
1139		1498
1140	=head3 CONTROLLING THE NUMBER OF THREADS	1499	=head3 CONTROLLING THE NUMBER OF THREADS
1141		1500
1142	=over	1501	=over
…		…
1175		1534
1176	Under normal circumstances you don't need to call this function.	1535	Under normal circumstances you don't need to call this function.
1177		1536
1178	=item IO::AIO::max_idle $nthreads	1537	=item IO::AIO::max_idle $nthreads
1179		1538
1180	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1539	Limit the number of threads (default: 4) that are allowed to idle
1181	threads that did not get a request to process within 10 seconds). That	1540	(i.e., threads that did not get a request to process within the idle
1182	means if a thread becomes idle while C<$nthreads> other threads are also	1541	timeout (default: 10 seconds). That means if a thread becomes idle while
1183	idle, it will free its resources and exit.	1542	C<$nthreads> other threads are also idle, it will free its resources and
		1543	exit.
1184		1544
1185	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1545	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1186	to allow for extremely high load situations, but want to free resources	1546	to allow for extremely high load situations, but want to free resources
1187	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1547	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1188		1548
1189	The default is probably ok in most situations, especially if thread	1549	The default is probably ok in most situations, especially if thread
1190	creation is fast. If thread creation is very slow on your system you might	1550	creation is fast. If thread creation is very slow on your system you might
1191	want to use larger values.	1551	want to use larger values.
1192		1552
		1553	=item IO::AIO::idle_timeout $seconds
		1554
		1555	Sets the minimum idle timeout (default 10) after which worker threads are
		1556	allowed to exit. SEe C<IO::AIO::max_idle>.
		1557
1193	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1558	=item IO::AIO::max_outstanding $maxreqs
1194		1559
1195	This is a very bad function to use in interactive programs because it	1560	This is a very bad function to use in interactive programs because it
1196	blocks, and a bad way to reduce concurrency because it is inexact: Better	1561	blocks, and a bad way to reduce concurrency because it is inexact: Better
1197	use an C<aio_group> together with a feed callback.	1562	use an C<aio_group> together with a feed callback.
1198		1563
1199	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1564	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1200	to queue up more than this number of requests, the next call to the	1565	do queue up more than this number of requests, the next call to the
1201	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1566	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1202	function will block until the limit is no longer exceeded.	1567	function will block until the limit is no longer exceeded.
1203		1568
1204	The default value is very large, so there is no practical limit on the	1569	The default value is very large, so there is no practical limit on the
1205	number of outstanding requests.	1570	number of outstanding requests.
1206		1571
1207	You can still queue as many requests as you want. Therefore,	1572	You can still queue as many requests as you want. Therefore,
1208	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1573	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1209	as a stop gap to shield against fatal memory overflow (with large values).	1574	as a stop gap to shield against fatal memory overflow (with large values).
1210		1575
1211	=back	1576	=back
1212		1577
1213	=head3 STATISTICAL INFORMATION	1578	=head3 STATISTICAL INFORMATION
…		…
1234	Returns the number of requests currently in the pending state (executed,	1599	Returns the number of requests currently in the pending state (executed,
1235	but not yet processed by poll_cb).	1600	but not yet processed by poll_cb).
1236		1601
1237	=back	1602	=back
1238		1603
		1604	=head3 MISCELLANEOUS FUNCTIONS
		1605
		1606	IO::AIO implements some functions that might be useful, but are not
		1607	asynchronous.
		1608
		1609	=over 4
		1610
		1611	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1612
		1613	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1614	but is blocking (this makes most sense if you know the input data is
		1615	likely cached already and the output filehandle is set to non-blocking
		1616	operations).
		1617
		1618	Returns the number of bytes copied, or C<-1> on error.
		1619
		1620	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1621
		1622	Simply calls the C<posix_fadvise> function (see its
		1623	manpage for details). The following advice constants are
		1624	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1625	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1626	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1627
		1628	On systems that do not implement C<posix_fadvise>, this function returns
		1629	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1630
		1631	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1632
		1633	Simply calls the C<posix_madvise> function (see its
		1634	manpage for details). The following advice constants are
		1635	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1636	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1637
		1638	On systems that do not implement C<posix_madvise>, this function returns
		1639	ENOSYS, otherwise the return value of C<posix_madvise>.
		1640
		1641	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1642
		1643	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1644	$scalar (see its manpage for details). The following protect
		1645	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1646	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1647
		1648	On systems that do not implement C<mprotect>, this function returns
		1649	ENOSYS, otherwise the return value of C<mprotect>.
		1650
		1651	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1652
		1653	Memory-maps a file (or anonymous memory range) and attaches it to the
		1654	given C<$scalar>, which will act like a string scalar.
		1655
		1656	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1657	change the string length, and most read-only operations such as copying it
		1658	or searching it with regexes and so on.
		1659
		1660	Anything else is unsafe and will, at best, result in memory leaks.
		1661
		1662	The memory map associated with the C<$scalar> is automatically removed
		1663	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1664	C<IO::AIO::munmap> functions are called.
		1665
		1666	This calls the C<mmap>(2) function internally. See your system's manual
		1667	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1668
		1669	The C<$length> must be larger than zero and smaller than the actual
		1670	filesize.
		1671
		1672	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1673	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1674
		1675	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1676	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1677	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1678	(which is set to C<MAP_ANON> if your system only provides this
		1679	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1680	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1681	C<IO::AIO::MAP_NONBLOCK>
		1682
		1683	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1684
		1685	C<$offset> is the offset from the start of the file - it generally must be
		1686	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1687
		1688	Example:
		1689
		1690	use Digest::MD5;
		1691	use IO::AIO;
		1692
		1693	open my $fh, "<verybigfile"
		1694	or die "$!";
		1695
		1696	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1697	or die "verybigfile: $!";
		1698
		1699	my $fast_md5 = md5 $data;
		1700
		1701	=item IO::AIO::munmap $scalar
		1702
		1703	Removes a previous mmap and undefines the C<$scalar>.
		1704
		1705	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1706
		1707	Calls the C<munlock> function, undoing the effects of a previous
		1708	C<aio_mlock> call (see its description for details).
		1709
		1710	=item IO::AIO::munlockall
		1711
		1712	Calls the C<munlockall> function.
		1713
		1714	On systems that do not implement C<munlockall>, this function returns
		1715	ENOSYS, otherwise the return value of C<munlockall>.
		1716
		1717	=back
		1718
1239	=cut	1719	=cut
1240		1720
1241	# support function to convert a fd into a perl filehandle
1242	sub _fd2fh {
1243	return undef if $_[0] < 0;
1244
1245	# try to generate nice filehandles
1246	my $sym = "IO::AIO::fd#$_[0]";
1247	local *$sym;
1248
1249	open *$sym, "+<&=$_[0]" # usually works under any unix
1250	or open *$sym, "<&=$_[0]" # cygwin needs this
1251	or open *$sym, ">&=$_[0]" # or this
1252	or return undef;
1253
1254	*$sym
1255	}
1256
1257	min_parallel 8;	1721	min_parallel 8;
1258		1722
1259	END { flush }	1723	END { flush }
1260		1724
1261	1;	1725	1;
		1726
		1727	=head1 EVENT LOOP INTEGRATION
		1728
		1729	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1730	automatically into many event loops:
		1731
		1732	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1733	use AnyEvent::AIO;
		1734
		1735	You can also integrate IO::AIO manually into many event loops, here are
		1736	some examples of how to do this:
		1737
		1738	# EV integration
		1739	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1740
		1741	# Event integration
		1742	Event->io (fd => IO::AIO::poll_fileno,
		1743	poll => 'r',
		1744	cb => \&IO::AIO::poll_cb);
		1745
		1746	# Glib/Gtk2 integration
		1747	add_watch Glib::IO IO::AIO::poll_fileno,
		1748	in => sub { IO::AIO::poll_cb; 1 };
		1749
		1750	# Tk integration
		1751	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1752	readable => \&IO::AIO::poll_cb);
		1753
		1754	# Danga::Socket integration
		1755	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1756	\&IO::AIO::poll_cb);
1262		1757
1263	=head2 FORK BEHAVIOUR	1758	=head2 FORK BEHAVIOUR
1264		1759
1265	This module should do "the right thing" when the process using it forks:	1760	This module should do "the right thing" when the process using it forks:
1266		1761
…		…
1284	bytes of memory. In addition, stat requests need a stat buffer (possibly	1779	bytes of memory. In addition, stat requests need a stat buffer (possibly
1285	a few hundred bytes), readdir requires a result buffer and so on. Perl	1780	a few hundred bytes), readdir requires a result buffer and so on. Perl
1286	scalars and other data passed into aio requests will also be locked and	1781	scalars and other data passed into aio requests will also be locked and
1287	will consume memory till the request has entered the done state.	1782	will consume memory till the request has entered the done state.
1288		1783
1289	This is now awfully much, so queuing lots of requests is not usually a	1784	This is not awfully much, so queuing lots of requests is not usually a
1290	problem.	1785	problem.
1291		1786
1292	Per-thread usage:	1787	Per-thread usage:
1293		1788
1294	In the execution phase, some aio requests require more memory for	1789	In the execution phase, some aio requests require more memory for
…		…
1299		1794
1300	Known bugs will be fixed in the next release.	1795	Known bugs will be fixed in the next release.
1301		1796
1302	=head1 SEE ALSO	1797	=head1 SEE ALSO
1303		1798
1304	L<Coro::AIO>.	1799	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1800	more natural syntax.
1305		1801
1306	=head1 AUTHOR	1802	=head1 AUTHOR
1307		1803
1308	Marc Lehmann <schmorp@schmorp.de>	1804	Marc Lehmann <schmorp@schmorp.de>
1309	http://home.schmorp.de/	1805	http://home.schmorp.de/

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