[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC vs.
Revision 1.233 by root, Mon Aug 13 01:01:04 2012 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
…		…
25	my $req = aio_unlink "/tmp/file", sub { };	25	my $req = aio_unlink "/tmp/file", sub { };
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
31	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32	use AnyEvent::AIO;
33
34	# EV integration
35	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37	# Event integration
38	Event->io (fd => IO::AIO::poll_fileno,
39	poll => 'r',
40	cb => \&IO::AIO::poll_cb);
41
42	# Glib/Gtk2 integration
43	add_watch Glib::IO IO::AIO::poll_fileno,
44	in => sub { IO::AIO::poll_cb; 1 };
45
46	# Tk integration
47	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48	readable => \&IO::AIO::poll_cb);
49
50	# Danga::Socket integration
51	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52	\&IO::AIO::poll_cb);
53		30
54	=head1 DESCRIPTION	31	=head1 DESCRIPTION
55		32
56	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
57	operating system supports. It is implemented as an interface to C<libeio>	34	operating system supports. It is implemented as an interface to C<libeio>
…		…
99		76
100	# register the IO::AIO callback with EV	77	# register the IO::AIO callback with EV
101	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102		79
103	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105	my $fh = shift	82	my $fh = shift
106	or die "error while opening: $!";	83	or die "error while opening: $!";
107		84
108	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
109	my $size = -s $fh;	86	my $size = -s $fh;
…		…
191	use common::sense;	168	use common::sense;
192		169
193	use base 'Exporter';	170	use base 'Exporter';
194		171
195	BEGIN {	172	BEGIN {
196	our $VERSION = '3.4';	173	our $VERSION = '4.15';
197		174
198	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	175	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
199	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
200	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
201	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
		179	aio_pathsync aio_readahead aio_fiemap
202	aio_rename aio_link aio_move aio_copy aio_group	180	aio_rename aio_link aio_move aio_copy aio_group
203	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
204	aio_chmod aio_utime aio_truncate	182	aio_chmod aio_utime aio_truncate
205	aio_msync aio_mtouch);	183	aio_msync aio_mtouch aio_mlock aio_mlockall
		184	aio_statvfs
		185	aio_wd);
206		186
207	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209	min_parallel max_parallel max_idle	189	min_parallel max_parallel max_idle idle_timeout
210	nreqs nready npending nthreads	190	nreqs nready npending nthreads
211	max_poll_time max_poll_reqs	191	max_poll_time max_poll_reqs
212	sendfile fadvise);	192	sendfile fadvise madvise
		193	mmap munmap munlock munlockall);
213		194
214	push @AIO_REQ, qw(aio_busy); # not exported	195	push @AIO_REQ, qw(aio_busy); # not exported
215		196
216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	197	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217		198
…		…
219	XSLoader::load ("IO::AIO", $VERSION);	200	XSLoader::load ("IO::AIO", $VERSION);
220	}	201	}
221		202
222	=head1 FUNCTIONS	203	=head1 FUNCTIONS
223		204
224	=head2 AIO REQUEST FUNCTIONS	205	=head2 QUICK OVERVIEW
		206
		207	This section simply lists the prototypes most of the functions for
		208	quick reference. See the following sections for function-by-function
		209	documentation.
		210
		211	aio_wd $pathname, $callback->($wd)
		212	aio_open $pathname, $flags, $mode, $callback->($fh)
		213	aio_close $fh, $callback->($status)
		214	aio_seek $fh,$offset,$whence, $callback->($offs)
		215	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		216	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		217	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		218	aio_readahead $fh,$offset,$length, $callback->($retval)
		219	aio_stat $fh_or_path, $callback->($status)
		220	aio_lstat $fh, $callback->($status)
		221	aio_statvfs $fh_or_path, $callback->($statvfs)
		222	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		223	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		224	aio_chmod $fh_or_path, $mode, $callback->($status)
		225	aio_truncate $fh_or_path, $offset, $callback->($status)
		226	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		227	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		228	aio_unlink $pathname, $callback->($status)
		229	aio_mknod $pathname, $mode, $dev, $callback->($status)
		230	aio_link $srcpath, $dstpath, $callback->($status)
		231	aio_symlink $srcpath, $dstpath, $callback->($status)
		232	aio_readlink $pathname, $callback->($link)
		233	aio_realpath $pathname, $callback->($link)
		234	aio_rename $srcpath, $dstpath, $callback->($status)
		235	aio_mkdir $pathname, $mode, $callback->($status)
		236	aio_rmdir $pathname, $callback->($status)
		237	aio_readdir $pathname, $callback->($entries)
		238	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		239	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		240	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
		242	aio_load $pathname, $data, $callback->($status)
		243	aio_copy $srcpath, $dstpath, $callback->($status)
		244	aio_move $srcpath, $dstpath, $callback->($status)
		245	aio_rmtree $pathname, $callback->($status)
		246	aio_sync $callback->($status)
		247	aio_syncfs $fh, $callback->($status)
		248	aio_fsync $fh, $callback->($status)
		249	aio_fdatasync $fh, $callback->($status)
		250	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		251	aio_pathsync $pathname, $callback->($status)
		252	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		253	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		254	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		255	aio_mlockall $flags, $callback->($status)
		256	aio_group $callback->(...)
		257	aio_nop $callback->()
		258
		259	$prev_pri = aioreq_pri [$pri]
		260	aioreq_nice $pri_adjust
		261
		262	IO::AIO::poll_wait
		263	IO::AIO::poll_cb
		264	IO::AIO::poll
		265	IO::AIO::flush
		266	IO::AIO::max_poll_reqs $nreqs
		267	IO::AIO::max_poll_time $seconds
		268	IO::AIO::min_parallel $nthreads
		269	IO::AIO::max_parallel $nthreads
		270	IO::AIO::max_idle $nthreads
		271	IO::AIO::idle_timeout $seconds
		272	IO::AIO::max_outstanding $maxreqs
		273	IO::AIO::nreqs
		274	IO::AIO::nready
		275	IO::AIO::npending
		276
		277	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		278	IO::AIO::fadvise $fh, $offset, $len, $advice
		279	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		280	IO::AIO::munmap $scalar
		281	IO::AIO::madvise $scalar, $offset, $length, $advice
		282	IO::AIO::mprotect $scalar, $offset, $length, $protect
		283	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		284	IO::AIO::munlockall
		285
		286	=head2 API NOTES
225		287
226	All the C<aio_*> calls are more or less thin wrappers around the syscall	288	All the C<aio_*> calls are more or less thin wrappers around the syscall
227	with the same name (sans C<aio_>). The arguments are similar or identical,	289	with the same name (sans C<aio_>). The arguments are similar or identical,
228	and they all accept an additional (and optional) C<$callback> argument	290	and they all accept an additional (and optional) C<$callback> argument
229	which must be a code reference. This code reference will get called with	291	which must be a code reference. This code reference will be called after
230	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	292	the syscall has been executed in an asynchronous fashion. The results
231	perl, which usually delivers "false") as its sole argument after the given	293	of the request will be passed as arguments to the callback (and, if an
232	syscall has been executed asynchronously.	294	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		295	most syscalls return C<-1> on error, unlike perl, which usually delivers
		296	"false").
		297
		298	Some requests (such as C<aio_readdir>) pass the actual results and
		299	communicate failures by passing C<undef>.
233		300
234	All functions expecting a filehandle keep a copy of the filehandle	301	All functions expecting a filehandle keep a copy of the filehandle
235	internally until the request has finished.	302	internally until the request has finished.
236		303
237	All functions return request objects of type L<IO::AIO::REQ> that allow	304	All functions return request objects of type L<IO::AIO::REQ> that allow
238	further manipulation of those requests while they are in-flight.	305	further manipulation of those requests while they are in-flight.
239		306
240	The pathnames you pass to these routines I<must> be absolute and	307	The pathnames you pass to these routines I<should> be absolute. The
241	encoded as octets. The reason for the former is that at the time the	308	reason for this is that at the time the request is being executed, the
242	request is being executed, the current working directory could have	309	current working directory could have changed. Alternatively, you can
243	changed. Alternatively, you can make sure that you never change the	310	make sure that you never change the current working directory anywhere
244	current working directory anywhere in the program and then use relative	311	in the program and then use relative paths. You can also take advantage
245	paths.	312	of IO::AIOs working directory abstraction, that lets you specify paths
		313	relative to some previously-opened "working directory object" - see the
		314	description of the C<IO::AIO::WD> class later in this document.
246		315
247	To encode pathnames as octets, either make sure you either: a) always pass	316	To encode pathnames as octets, either make sure you either: a) always pass
248	in filenames you got from outside (command line, readdir etc.) without	317	in filenames you got from outside (command line, readdir etc.) without
249	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	318	tinkering, b) are in your native filesystem encoding, c) use the Encode
250	your pathnames to the locale (or other) encoding in effect in the user	319	module and encode your pathnames to the locale (or other) encoding in
251	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	320	effect in the user environment, d) use Glib::filename_from_unicode on
252	use something else to ensure your scalar has the correct contents.	321	unicode filenames or e) use something else to ensure your scalar has the
		322	correct contents.
253		323
254	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	324	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
255	handles correctly whether it is set or not.	325	handles correctly whether it is set or not.
		326
		327	=head2 AIO REQUEST FUNCTIONS
256		328
257	=over 4	329	=over 4
258		330
259	=item $prev_pri = aioreq_pri [$pri]	331	=item $prev_pri = aioreq_pri [$pri]
260		332
…		…
290		362
291		363
292	=item aio_open $pathname, $flags, $mode, $callback->($fh)	364	=item aio_open $pathname, $flags, $mode, $callback->($fh)
293		365
294	Asynchronously open or create a file and call the callback with a newly	366	Asynchronously open or create a file and call the callback with a newly
295	created filehandle for the file.	367	created filehandle for the file (or C<undef> in case of an error).
296		368
297	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	369	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
298	for an explanation.	370	for an explanation.
299		371
300	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	372	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
307	by the umask in effect then the request is being executed, so better never	379	by the umask in effect then the request is being executed, so better never
308	change the umask.	380	change the umask.
309		381
310	Example:	382	Example:
311		383
312	aio_open "/etc/passwd", O_RDONLY, 0, sub {	384	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313	if ($_[0]) {	385	if ($_[0]) {
314	print "open successful, fh is $_[0]\n";	386	print "open successful, fh is $_[0]\n";
315	...	387	...
316	} else {	388	} else {
317	die "open failed: $!\n";	389	die "open failed: $!\n";
318	}	390	}
319	};	391	};
320		392
		393	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		394	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		395	following POSIX and non-POSIX constants are available (missing ones on
		396	your system are, as usual, C<0>):
		397
		398	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		399	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		400	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		401
321		402
322	=item aio_close $fh, $callback->($status)	403	=item aio_close $fh, $callback->($status)
323		404
324	Asynchronously close a file and call the callback with the result	405	Asynchronously close a file and call the callback with the result
325	code.	406	code.
…		…
333		414
334	Or in other words: the file descriptor will be closed, but it will not be	415	Or in other words: the file descriptor will be closed, but it will not be
335	free for reuse until the perl filehandle is closed.	416	free for reuse until the perl filehandle is closed.
336		417
337	=cut	418	=cut
		419
		420	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		421
		422	Seeks the filehandle to the new C<$offset>, similarly to perl's
		423	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		424	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		425	C<IO::AIO::SEEK_END>).
		426
		427	The resulting absolute offset will be passed to the callback, or C<-1> in
		428	case of an error.
		429
		430	In theory, the C<$whence> constants could be different than the
		431	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		432	so don't panic.
		433
		434	As a GNU/Linux (and maybe Solaris) extension, also the constants
		435	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		436	could be found. No guarantees about suitability for use in C<aio_seek> or
		437	Perl's C<sysseek> can be made though, although I would naively assume they
		438	"just work".
338		439
339	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	440	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
340		441
341	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	442	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
342		443
…		…
375		476
376	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	477	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377	reading at byte offset C<$in_offset>, and starts writing at the current	478	reading at byte offset C<$in_offset>, and starts writing at the current
378	file offset of C<$out_fh>. Because of that, it is not safe to issue more	479	file offset of C<$out_fh>. Because of that, it is not safe to issue more
379	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	480	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380	other.	481	other. The same C<$in_fh> works fine though, as this function does not
		482	move or use the file offset of C<$in_fh>.
381		483
		484	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		485	are written, and there is no way to find out how many more bytes have been
		486	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		487	number of bytes written to C<$out_fh>. Only if the result value equals
		488	C<$length> one can assume that C<$length> bytes have been read.
		489
		490	Unlike with other C<aio_> functions, it makes a lot of sense to use
		491	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		492	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		493	the socket I/O will be non-blocking. Note, however, that you can run
		494	into a trap where C<aio_sendfile> reads some data with readahead, then
		495	fails to write all data, and when the socket is ready the next time, the
		496	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		497	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		498	resource usage.
		499
382	This call tries to make use of a native C<sendfile> syscall to provide	500	This call tries to make use of a native C<sendfile>-like syscall to
383	zero-copy operation. For this to work, C<$out_fh> should refer to a	501	provide zero-copy operation. For this to work, C<$out_fh> should refer to
384	socket, and C<$in_fh> should refer to mmap'able file.	502	a socket, and C<$in_fh> should refer to an mmap'able file.
385		503
386	If a native sendfile cannot be found or it fails with C<ENOSYS>,	504	If a native sendfile cannot be found or it fails with C<ENOSYS>,
387	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	505	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388	it will be emulated, so you can call C<aio_sendfile> on any type of	506	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389	filehandle regardless of the limitations of the operating system.	507	type of filehandle regardless of the limitations of the operating system.
390		508
391	Please note, however, that C<aio_sendfile> can read more bytes from	509	As native sendfile syscalls (as practically any non-POSIX interface hacked
392	C<$in_fh> than are written, and there is no way to find out how many	510	together in a hurry to improve benchmark numbers) tend to be rather buggy
393	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	511	on many systems, this implementation tries to work around some known bugs
394	provides the number of bytes written to C<$out_fh>. Only if the result	512	in Linux and FreeBSD kernels (probably others, too), but that might fail,
395	value equals C<$length> one can assume that C<$length> bytes have been	513	so you really really should check the return value of C<aio_sendfile> -
396	read.	514	fewre bytes than expected might have been transferred.
397		515
398		516
399	=item aio_readahead $fh,$offset,$length, $callback->($retval)	517	=item aio_readahead $fh,$offset,$length, $callback->($retval)
400		518
401	C<aio_readahead> populates the page cache with data from a file so that	519	C<aio_readahead> populates the page cache with data from a file so that
…		…
424		542
425	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	543	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
426	error when stat'ing a large file, the results will be silently truncated	544	error when stat'ing a large file, the results will be silently truncated
427	unless perl itself is compiled with large file support.	545	unless perl itself is compiled with large file support.
428		546
		547	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		548	following constants and functions (if not implemented, the constants will
		549	be C<0> and the functions will either C<croak> or fall back on traditional
		550	behaviour).
		551
		552	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		553	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		554	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		555
429	Example: Print the length of F</etc/passwd>:	556	Example: Print the length of F</etc/passwd>:
430		557
431	aio_stat "/etc/passwd", sub {	558	aio_stat "/etc/passwd", sub {
432	$_[0] and die "stat failed: $!";	559	$_[0] and die "stat failed: $!";
433	print "size is ", -s _, "\n";	560	print "size is ", -s _, "\n";
434	};	561	};
435		562
436		563
		564	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		565
		566	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		567	whether a file handle or path was passed.
		568
		569	On success, the callback is passed a hash reference with the following
		570	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		571	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		572	is passed.
		573
		574	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		575	C<ST_NOSUID>.
		576
		577	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		578	their correct value when available, or to C<0> on systems that do
		579	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		580	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		581	C<ST_NODIRATIME> and C<ST_RELATIME>.
		582
		583	Example: stat C</wd> and dump out the data if successful.
		584
		585	aio_statvfs "/wd", sub {
		586	my $f = $_[0]
		587	or die "statvfs: $!";
		588
		589	use Data::Dumper;
		590	say Dumper $f;
		591	};
		592
		593	# result:
		594	{
		595	bsize => 1024,
		596	bfree => 4333064312,
		597	blocks => 10253828096,
		598	files => 2050765568,
		599	flag => 4096,
		600	favail => 2042092649,
		601	bavail => 4333064312,
		602	ffree => 2042092649,
		603	namemax => 255,
		604	frsize => 1024,
		605	fsid => 1810
		606	}
		607
		608
437	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	609	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
438		610
439	Works like perl's C<utime> function (including the special case of $atime	611	Works like perl's C<utime> function (including the special case of $atime
440	and $mtime being undef). Fractional times are supported if the underlying	612	and $mtime being undef). Fractional times are supported if the underlying
441	syscalls support them.	613	syscalls support them.
…		…
468	=item aio_truncate $fh_or_path, $offset, $callback->($status)	640	=item aio_truncate $fh_or_path, $offset, $callback->($status)
469		641
470	Works like truncate(2) or ftruncate(2).	642	Works like truncate(2) or ftruncate(2).
471		643
472		644
		645	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		646
		647	Allocates or freed disk space according to the C<$mode> argument. See the
		648	linux C<fallocate> docuemntation for details.
		649
		650	C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
		651	to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \|
		652	IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
		653
		654	The file system block size used by C<fallocate> is presumably the
		655	C<f_bsize> returned by C<statvfs>.
		656
		657	If C<fallocate> isn't available or cannot be emulated (currently no
		658	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		659
		660
473	=item aio_chmod $fh_or_path, $mode, $callback->($status)	661	=item aio_chmod $fh_or_path, $mode, $callback->($status)
474		662
475	Works like perl's C<chmod> function.	663	Works like perl's C<chmod> function.
476		664
477		665
…		…
479		667
480	Asynchronously unlink (delete) a file and call the callback with the	668	Asynchronously unlink (delete) a file and call the callback with the
481	result code.	669	result code.
482		670
483		671
484	=item aio_mknod $path, $mode, $dev, $callback->($status)	672	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
485		673
486	[EXPERIMENTAL]	674	[EXPERIMENTAL]
487		675
488	Asynchronously create a device node (or fifo). See mknod(2).	676	Asynchronously create a device node (or fifo). See mknod(2).
489		677
490	The only (POSIX-) portable way of calling this function is:	678	The only (POSIX-) portable way of calling this function is:
491		679
492	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	680	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
493		681
		682	See C<aio_stat> for info about some potentially helpful extra constants
		683	and functions.
494		684
495	=item aio_link $srcpath, $dstpath, $callback->($status)	685	=item aio_link $srcpath, $dstpath, $callback->($status)
496		686
497	Asynchronously create a new link to the existing object at C<$srcpath> at	687	Asynchronously create a new link to the existing object at C<$srcpath> at
498	the path C<$dstpath> and call the callback with the result code.	688	the path C<$dstpath> and call the callback with the result code.
…		…
502		692
503	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	693	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
504	the path C<$dstpath> and call the callback with the result code.	694	the path C<$dstpath> and call the callback with the result code.
505		695
506		696
507	=item aio_readlink $path, $callback->($link)	697	=item aio_readlink $pathname, $callback->($link)
508		698
509	Asynchronously read the symlink specified by C<$path> and pass it to	699	Asynchronously read the symlink specified by C<$path> and pass it to
510	the callback. If an error occurs, nothing or undef gets passed to the	700	the callback. If an error occurs, nothing or undef gets passed to the
511	callback.	701	callback.
512		702
513		703
		704	=item aio_realpath $pathname, $callback->($path)
		705
		706	Asynchronously make the path absolute and resolve any symlinks in
		707	C<$path>. The resulting path only consists of directories (Same as
		708	L<Cwd::realpath>).
		709
		710	This request can be used to get the absolute path of the current working
		711	directory by passing it a path of F<.> (a single dot).
		712
		713
514	=item aio_rename $srcpath, $dstpath, $callback->($status)	714	=item aio_rename $srcpath, $dstpath, $callback->($status)
515		715
516	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	716	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
517	rename(2) and call the callback with the result code.	717	rename(2) and call the callback with the result code.
518		718
…		…
540	array-ref with the filenames.	740	array-ref with the filenames.
541		741
542		742
543	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	743	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
544		744
545	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	745	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
546	behaviour and output format. In case of an error, C<$entries> will be	746	tune behaviour and output format. In case of an error, C<$entries> will be
547	C<undef>.	747	C<undef>.
548		748
549	The flags are a combination of the following constants, ORed together (the	749	The flags are a combination of the following constants, ORed together (the
550	flags will also be passed to the callback, possibly modified):	750	flags will also be passed to the callback, possibly modified):
551		751
552	=over 4	752	=over 4
553		753
554	=item IO::AIO::READDIR_DENTS	754	=item IO::AIO::READDIR_DENTS
555		755
556	When this flag is off, then the callback gets an arrayref with of names	756	When this flag is off, then the callback gets an arrayref consisting of
557	only (as with C<aio_readdir>), otherwise it gets an arrayref with	757	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
558	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	758	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
559	entry in more detail.	759	entry in more detail.
560		760
561	C<$name> is the name of the entry.	761	C<$name> is the name of the entry.
562		762
…		…
575	systems that do not deliver the inode information.	775	systems that do not deliver the inode information.
576		776
577	=item IO::AIO::READDIR_DIRS_FIRST	777	=item IO::AIO::READDIR_DIRS_FIRST
578		778
579	When this flag is set, then the names will be returned in an order where	779	When this flag is set, then the names will be returned in an order where
580	likely directories come first. This is useful when you need to quickly	780	likely directories come first, in optimal stat order. This is useful when
581	find directories, or you want to find all directories while avoiding to	781	you need to quickly find directories, or you want to find all directories
582	stat() each entry.	782	while avoiding to stat() each entry.
583		783
584	If the system returns type information in readdir, then this is used	784	If the system returns type information in readdir, then this is used
585	to find directories directly. Otherwise, likely directories are files	785	to find directories directly. Otherwise, likely directories are names
586	beginning with ".", or otherwise files with no dots, of which files with	786	beginning with ".", or otherwise names with no dots, of which names with
587	short names are tried first.	787	short names are tried first.
588		788
589	=item IO::AIO::READDIR_STAT_ORDER	789	=item IO::AIO::READDIR_STAT_ORDER
590		790
591	When this flag is set, then the names will be returned in an order	791	When this flag is set, then the names will be returned in an order
…		…
598		798
599	=item IO::AIO::READDIR_FOUND_UNKNOWN	799	=item IO::AIO::READDIR_FOUND_UNKNOWN
600		800
601	This flag should not be set when calling C<aio_readdirx>. Instead, it	801	This flag should not be set when calling C<aio_readdirx>. Instead, it
602	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	802	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
603	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	803	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
604	C<$type>'s are known, which can be used to speed up some algorithms.	804	C<$type>'s are known, which can be used to speed up some algorithms.
605		805
606	=back	806	=back
607		807
608		808
609	=item aio_load $path, $data, $callback->($status)	809	=item aio_load $pathname, $data, $callback->($status)
610		810
611	This is a composite request that tries to fully load the given file into	811	This is a composite request that tries to fully load the given file into
612	memory. Status is the same as with aio_read.	812	memory. Status is the same as with aio_read.
613		813
614	=cut	814	=cut
…		…
736	if ($_[0] && $! == EXDEV) {	936	if ($_[0] && $! == EXDEV) {
737	aioreq_pri $pri;	937	aioreq_pri $pri;
738	add $grp aio_copy $src, $dst, sub {	938	add $grp aio_copy $src, $dst, sub {
739	$grp->result ($_[0]);	939	$grp->result ($_[0]);
740		940
741	if (!$_[0]) {	941	unless ($_[0]) {
742	aioreq_pri $pri;	942	aioreq_pri $pri;
743	add $grp aio_unlink $src;	943	add $grp aio_unlink $src;
744	}	944	}
745	};	945	};
746	} else {	946	} else {
…		…
749	};	949	};
750		950
751	$grp	951	$grp
752	}	952	}
753		953
754	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	954	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
755		955
756	Scans a directory (similar to C<aio_readdir>) but additionally tries to	956	Scans a directory (similar to C<aio_readdir>) but additionally tries to
757	efficiently separate the entries of directory C<$path> into two sets of	957	efficiently separate the entries of directory C<$path> into two sets of
758	names, directories you can recurse into (directories), and ones you cannot	958	names, directories you can recurse into (directories), and ones you cannot
759	recurse into (everything else, including symlinks to directories).	959	recurse into (everything else, including symlinks to directories).
…		…
790	Then entries will be sorted into likely directories a non-initial dot	990	Then entries will be sorted into likely directories a non-initial dot
791	currently) and likely non-directories (see C<aio_readdirx>). Then every	991	currently) and likely non-directories (see C<aio_readdirx>). Then every
792	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	992	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
793	in order of their inode numbers. If that succeeds, it assumes that the	993	in order of their inode numbers. If that succeeds, it assumes that the
794	entry is a directory or a symlink to directory (which will be checked	994	entry is a directory or a symlink to directory (which will be checked
795	seperately). This is often faster than stat'ing the entry itself because	995	separately). This is often faster than stat'ing the entry itself because
796	filesystems might detect the type of the entry without reading the inode	996	filesystems might detect the type of the entry without reading the inode
797	data (e.g. ext2fs filetype feature), even on systems that cannot return	997	data (e.g. ext2fs filetype feature), even on systems that cannot return
798	the filetype information on readdir.	998	the filetype information on readdir.
799		999
800	If the known number of directories (link count - 2) has been reached, the	1000	If the known number of directories (link count - 2) has been reached, the
…		…
816		1016
817	my $grp = aio_group $cb;	1017	my $grp = aio_group $cb;
818		1018
819	$maxreq = 4 if $maxreq <= 0;	1019	$maxreq = 4 if $maxreq <= 0;
820		1020
821	# stat once	1021	# get a wd object
822	aioreq_pri $pri;	1022	aioreq_pri $pri;
823	add $grp aio_stat $path, sub {	1023	add $grp aio_wd $path, sub {
		1024	$_[0]
824	return $grp->result () if $_[0];	1025	or return $grp->result ();
825	my $now = time;
826	my $hash1 = join ":", (stat _)[0,1,3,7,9];
827		1026
828	# read the directory entries	1027	my $wd = [shift, "."];
		1028
		1029	# stat once
829	aioreq_pri $pri;	1030	aioreq_pri $pri;
830	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1031	add $grp aio_stat $wd, sub {
831	my $entries = shift
832	or return $grp->result ();	1032	return $grp->result () if $_[0];
		1033	my $now = time;
		1034	my $hash1 = join ":", (stat _)[0,1,3,7,9];
833		1035
834	# stat the dir another time	1036	# read the directory entries
835	aioreq_pri $pri;	1037	aioreq_pri $pri;
		1038	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1039	my $entries = shift
		1040	or return $grp->result ();
		1041
		1042	# stat the dir another time
		1043	aioreq_pri $pri;
836	add $grp aio_stat $path, sub {	1044	add $grp aio_stat $wd, sub {
837	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1045	my $hash2 = join ":", (stat _)[0,1,3,7,9];
838		1046
839	my $ndirs;	1047	my $ndirs;
840		1048
841	# take the slow route if anything looks fishy	1049	# take the slow route if anything looks fishy
842	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1050	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
843	$ndirs = -1;	1051	$ndirs = -1;
844	} else {	1052	} else {
845	# if nlink == 2, we are finished	1053	# if nlink == 2, we are finished
846	# for non-posix-fs's, we rely on nlink < 2	1054	# for non-posix-fs's, we rely on nlink < 2
847	$ndirs = (stat _)[3] - 2	1055	$ndirs = (stat _)[3] - 2
848	or return $grp->result ([], $entries);	1056	or return $grp->result ([], $entries);
849	}	1057	}
850		1058
851	my (@dirs, @nondirs);	1059	my (@dirs, @nondirs);
852		1060
853	my $statgrp = add $grp aio_group sub {	1061	my $statgrp = add $grp aio_group sub {
854	$grp->result (\@dirs, \@nondirs);	1062	$grp->result (\@dirs, \@nondirs);
855	};	1063	};
856		1064
857	limit $statgrp $maxreq;	1065	limit $statgrp $maxreq;
858	feed $statgrp sub {	1066	feed $statgrp sub {
859	return unless @$entries;	1067	return unless @$entries;
860	my $entry = shift @$entries;	1068	my $entry = shift @$entries;
861		1069
862	aioreq_pri $pri;	1070	aioreq_pri $pri;
		1071	$wd->[1] = "$entry/.";
863	add $statgrp aio_stat "$path/$entry/.", sub {	1072	add $statgrp aio_stat $wd, sub {
864	if ($_[0] < 0) {	1073	if ($_[0] < 0) {
865	push @nondirs, $entry;	1074	push @nondirs, $entry;
866	} else {	1075	} else {
867	# need to check for real directory	1076	# need to check for real directory
868	aioreq_pri $pri;	1077	aioreq_pri $pri;
		1078	$wd->[1] = $entry;
869	add $statgrp aio_lstat "$path/$entry", sub {	1079	add $statgrp aio_lstat $wd, sub {
870	if (-d _) {	1080	if (-d _) {
871	push @dirs, $entry;	1081	push @dirs, $entry;
872		1082
873	unless (--$ndirs) {	1083	unless (--$ndirs) {
874	push @nondirs, @$entries;	1084	push @nondirs, @$entries;
875	feed $statgrp;	1085	feed $statgrp;
		1086	}
		1087	} else {
		1088	push @nondirs, $entry;
876	}	1089	}
877	} else {
878	push @nondirs, $entry;
879	}	1090	}
880	}	1091	}
881	}	1092	};
882	};	1093	};
883	};	1094	};
884	};	1095	};
885	};	1096	};
886	};	1097	};
887		1098
888	$grp	1099	$grp
889	}	1100	}
890		1101
891	=item aio_rmtree $path, $callback->($status)	1102	=item aio_rmtree $pathname, $callback->($status)
892		1103
893	Delete a directory tree starting (and including) C<$path>, return the	1104	Delete a directory tree starting (and including) C<$path>, return the
894	status of the final C<rmdir> only. This is a composite request that	1105	status of the final C<rmdir> only. This is a composite request that
895	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1106	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
896	everything else.	1107	everything else.
…		…
938	callback with the fdatasync result code.	1149	callback with the fdatasync result code.
939		1150
940	If this call isn't available because your OS lacks it or it couldn't be	1151	If this call isn't available because your OS lacks it or it couldn't be
941	detected, it will be emulated by calling C<fsync> instead.	1152	detected, it will be emulated by calling C<fsync> instead.
942		1153
		1154	=item aio_syncfs $fh, $callback->($status)
		1155
		1156	Asynchronously call the syncfs syscall to sync the filesystem associated
		1157	to the given filehandle and call the callback with the syncfs result
		1158	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1159	errno to C<ENOSYS> nevertheless.
		1160
943	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1161	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
944		1162
945	Sync the data portion of the file specified by C<$offset> and C<$length>	1163	Sync the data portion of the file specified by C<$offset> and C<$length>
946	to disk (but NOT the metadata), by calling the Linux-specific	1164	to disk (but NOT the metadata), by calling the Linux-specific
947	sync_file_range call. If sync_file_range is not available or it returns	1165	sync_file_range call. If sync_file_range is not available or it returns
…		…
950	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1168	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
951	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1169	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
952	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1170	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
953	manpage for details.	1171	manpage for details.
954		1172
955	=item aio_pathsync $path, $callback->($status)	1173	=item aio_pathsync $pathname, $callback->($status)
956		1174
957	This request tries to open, fsync and close the given path. This is a	1175	This request tries to open, fsync and close the given path. This is a
958	composite request intended to sync directories after directory operations	1176	composite request intended to sync directories after directory operations
959	(E.g. rename). This might not work on all operating systems or have any	1177	(E.g. rename). This might not work on all operating systems or have any
960	specific effect, but usually it makes sure that directory changes get	1178	specific effect, but usually it makes sure that directory changes get
…		…
994	}	1212	}
995		1213
996	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1214	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
997		1215
998	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1216	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
999	scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note	1217	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1218	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1000	that the scalar must only be modified in-place while an aio operation is	1219	scalar must only be modified in-place while an aio operation is pending on
1001	pending on it).	1220	it).
1002		1221
1003	It calls the C<msync> function of your OS, if available, with the memory	1222	It calls the C<msync> function of your OS, if available, with the memory
1004	area starting at C<$offset> in the string and ending C<$length> bytes	1223	area starting at C<$offset> in the string and ending C<$length> bytes
1005	later. If C<$length> is negative, counts from the end, and if C<$length>	1224	later. If C<$length> is negative, counts from the end, and if C<$length>
1006	is C<undef>, then it goes till the end of the string. The flags can be	1225	is C<undef>, then it goes till the end of the string. The flags can be
…		…
1017	as for C<aio_msync>, above, except for flags, which must be either	1236	as for C<aio_msync>, above, except for flags, which must be either
1018	C<0> (which reads all pages and ensures they are instantiated) or	1237	C<0> (which reads all pages and ensures they are instantiated) or
1019	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1238	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1020	writing an octet from it, which dirties the page).	1239	writing an octet from it, which dirties the page).
1021		1240
		1241	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1242
		1243	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1244	scalars.
		1245
		1246	It reads in all the pages of the underlying storage into memory (if any)
		1247	and locks them, so they are not getting swapped/paged out or removed.
		1248
		1249	If C<$length> is undefined, then the scalar will be locked till the end.
		1250
		1251	On systems that do not implement C<mlock>, this function returns C<-1>
		1252	and sets errno to C<ENOSYS>.
		1253
		1254	Note that the corresponding C<munlock> is synchronous and is
		1255	documented under L<MISCELLANEOUS FUNCTIONS>.
		1256
		1257	Example: open a file, mmap and mlock it - both will be undone when
		1258	C<$data> gets destroyed.
		1259
		1260	open my $fh, "<", $path or die "$path: $!";
		1261	my $data;
		1262	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1263	aio_mlock $data; # mlock in background
		1264
		1265	=item aio_mlockall $flags, $callback->($status)
		1266
		1267	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1268	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1269
		1270	On systems that do not implement C<mlockall>, this function returns C<-1>
		1271	and sets errno to C<ENOSYS>.
		1272
		1273	Note that the corresponding C<munlockall> is synchronous and is
		1274	documented under L<MISCELLANEOUS FUNCTIONS>.
		1275
		1276	Example: asynchronously lock all current and future pages into memory.
		1277
		1278	aio_mlockall IO::AIO::MCL_FUTURE;
		1279
		1280	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1281
		1282	Queries the extents of the given file (by calling the Linux FIEMAP ioctl,
		1283	see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the
		1284	C<ioctl> is not available on your OS, then this request will fail with
		1285	C<ENOSYS>.
		1286
		1287	C<$start> is the starting offset to query extents for, C<$length> is the
		1288	size of the range to query - if it is C<undef>, then the whole file will
		1289	be queried.
		1290
		1291	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1292	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1293	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1294	the data portion.
		1295
		1296	C<$count> is the maximum number of extent records to return. If it is
		1297	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1298	case, if it is C<0>, then the callback receives the number of extents
		1299	instead of the extents themselves (which is unreliable, see below).
		1300
		1301	If an error occurs, the callback receives no arguments. The special
		1302	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1303
		1304	Otherwise, the callback receives an array reference with extent
		1305	structures. Each extent structure is an array reference itself, with the
		1306	following members:
		1307
		1308	[$logical, $physical, $length, $flags]
		1309
		1310	Flags is any combination of the following flag values (typically either C<0>
		1311	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1312
		1313	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1314	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1315	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1316	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1317	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1318	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1319
		1320	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1321	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1322	it to return all extents of a range for files with large number of
		1323	extents. The code works around all these issues if C<$count> is undef.
		1324
1022	=item aio_group $callback->(...)	1325	=item aio_group $callback->(...)
1023		1326
1024	This is a very special aio request: Instead of doing something, it is a	1327	This is a very special aio request: Instead of doing something, it is a
1025	container for other aio requests, which is useful if you want to bundle	1328	container for other aio requests, which is useful if you want to bundle
1026	many requests into a single, composite, request with a definite callback	1329	many requests into a single, composite, request with a definite callback
…		…
1062	like sleep and file handle readable/writable, the overhead this creates is	1365	like sleep and file handle readable/writable, the overhead this creates is
1063	immense (it blocks a thread for a long time) so do not use this function	1366	immense (it blocks a thread for a long time) so do not use this function
1064	except to put your application under artificial I/O pressure.	1367	except to put your application under artificial I/O pressure.
1065		1368
1066	=back	1369	=back
		1370
		1371
		1372	=head2 IO::AIO::WD - multiple working directories
		1373
		1374	Your process only has one current working directory, which is used by all
		1375	threads. This makes it hard to use relative paths (some other component
		1376	could call C<chdir> at any time, and it is hard to control when the path
		1377	will be used by IO::AIO).
		1378
		1379	One solution for this is to always use absolute paths. This usually works,
		1380	but can be quite slow (the kernel has to walk the whole path on every
		1381	access), and can also be a hassle to implement.
		1382
		1383	Newer POSIX systems have a number of functions (openat, fdopendir,
		1384	futimensat and so on) that make it possible to specify working directories
		1385	per operation.
		1386
		1387	For portability, and because the clowns who "designed", or shall I write,
		1388	perpetrated this new interface were obviously half-drunk, this abstraction
		1389	cannot be perfect, though.
		1390
		1391	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1392	object. This object stores the canonicalised, absolute version of the
		1393	path, and on systems that allow it, also a directory file descriptor.
		1394
		1395	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1396	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1397	object and a pathname instead (or the IO::AIO::WD object alone, which
		1398	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1399	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1400	to that IO::AIO::WD object.
		1401
		1402	For example, to get a wd object for F</etc> and then stat F<passwd>
		1403	inside, you would write:
		1404
		1405	aio_wd "/etc", sub {
		1406	my $etcdir = shift;
		1407
		1408	# although $etcdir can be undef on error, there is generally no reason
		1409	# to check for errors here, as aio_stat will fail with ENOENT
		1410	# when $etcdir is undef.
		1411
		1412	aio_stat [$etcdir, "passwd"], sub {
		1413	# yay
		1414	};
		1415	};
		1416
		1417	That C<aio_wd> is a request and not a normal function shows that creating
		1418	an IO::AIO::WD object is itself a potentially blocking operation, which is
		1419	why it is done asynchronously.
		1420
		1421	To stat the directory obtained with C<aio_wd> above, one could write
		1422	either of the following three request calls:
		1423
		1424	aio_lstat "/etc" , sub { ... # pathname as normal string
		1425	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1426	aio_lstat $wd , sub { ... # shorthand for the previous
		1427
		1428	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1429	object and the pathname string, so you could write the following without
		1430	causing any issues due to C<$path> getting reused:
		1431
		1432	my $path = [$wd, undef];
		1433
		1434	for my $name (qw(abc def ghi)) {
		1435	$path->[1] = $name;
		1436	aio_stat $path, sub {
		1437	# ...
		1438	};
		1439	}
		1440
		1441	There are some caveats: when directories get renamed (or deleted), the
		1442	pathname string doesn't change, so will point to the new directory (or
		1443	nowhere at all), while the directory fd, if available on the system,
		1444	will still point to the original directory. Most functions accepting a
		1445	pathname will use the directory fd on newer systems, and the string on
		1446	older systems. Some functions (such as realpath) will always rely on the
		1447	string form of the pathname.
		1448
		1449	So this fucntionality is mainly useful to get some protection against
		1450	C<chdir>, to easily get an absolute path out of a relative path for future
		1451	reference, and to speed up doing many operations in the same directory
		1452	(e.g. when stat'ing all files in a directory).
		1453
		1454	The following functions implement this working directory abstraction:
		1455
		1456	=over 4
		1457
		1458	=item aio_wd $pathname, $callback->($wd)
		1459
		1460	Asynchonously canonicalise the given pathname and convert it to an
		1461	IO::AIO::WD object representing it. If possible and supported on the
		1462	system, also open a directory fd to speed up pathname resolution relative
		1463	to this working directory.
		1464
		1465	If something goes wrong, then C<undef> is passwd to the callback instead
		1466	of a working directory object and C<$!> is set appropriately. Since
		1467	passing C<undef> as working directory component of a pathname fails the
		1468	request with C<ENOENT>, there is often no need for error checking in the
		1469	C<aio_wd> callback, as future requests using the value will fail in the
		1470	expected way.
		1471
		1472	If this call isn't available because your OS lacks it or it couldn't be
		1473	detected, it will be emulated by calling C<fsync> instead.
		1474
		1475	=item IO::AIO::CWD
		1476
		1477	This is a compiletime constant (object) that represents the process
		1478	current working directory.
		1479
		1480	Specifying this object as working directory object for a pathname is as
		1481	if the pathname would be specified directly, without a directory object,
		1482	e.g., these calls are functionally identical:
		1483
		1484	aio_stat "somefile", sub { ... };
		1485	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1486
		1487	=back
		1488
1067		1489
1068	=head2 IO::AIO::REQ CLASS	1490	=head2 IO::AIO::REQ CLASS
1069		1491
1070	All non-aggregate C<aio_*> functions return an object of this class when	1492	All non-aggregate C<aio_*> functions return an object of this class when
1071	called in non-void context.	1493	called in non-void context.
…		…
1189		1611
1190	Sets a feeder/generator on this group: every group can have an attached	1612	Sets a feeder/generator on this group: every group can have an attached
1191	generator that generates requests if idle. The idea behind this is that,	1613	generator that generates requests if idle. The idea behind this is that,
1192	although you could just queue as many requests as you want in a group,	1614	although you could just queue as many requests as you want in a group,
1193	this might starve other requests for a potentially long time. For example,	1615	this might starve other requests for a potentially long time. For example,
1194	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1616	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1195	delaying any later requests for a long time.	1617	requests, delaying any later requests for a long time.
1196		1618
1197	To avoid this, and allow incremental generation of requests, you can	1619	To avoid this, and allow incremental generation of requests, you can
1198	instead a group and set a feeder on it that generates those requests. The	1620	instead a group and set a feeder on it that generates those requests. The
1199	feed callback will be called whenever there are few enough (see C<limit>,	1621	feed callback will be called whenever there are few enough (see C<limit>,
1200	below) requests active in the group itself and is expected to queue more	1622	below) requests active in the group itself and is expected to queue more
…		…
1249		1671
1250	See C<poll_cb> for an example.	1672	See C<poll_cb> for an example.
1251		1673
1252	=item IO::AIO::poll_cb	1674	=item IO::AIO::poll_cb
1253		1675
1254	Process some outstanding events on the result pipe. You have to call this	1676	Process some outstanding events on the result pipe. You have to call
1255	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1677	this regularly. Returns C<0> if all events could be processed (or there
1256	returned earlier for whatever reason. Returns immediately when no events	1678	were no events to process), or C<-1> if it returned earlier for whatever
1257	are outstanding. The amount of events processed depends on the settings of	1679	reason. Returns immediately when no events are outstanding. The amount of
1258	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1680	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1681	C<IO::AIO::max_poll_time>.
1259		1682
1260	If not all requests were processed for whatever reason, the filehandle	1683	If not all requests were processed for whatever reason, the filehandle
1261	will still be ready when C<poll_cb> returns, so normally you don't have to	1684	will still be ready when C<poll_cb> returns, so normally you don't have to
1262	do anything special to have it called later.	1685	do anything special to have it called later.
1263		1686
		1687	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1688	ready, it can be beneficial to call this function from loops which submit
		1689	a lot of requests, to make sure the results get processed when they become
		1690	available and not just when the loop is finished and the event loop takes
		1691	over again. This function returns very fast when there are no outstanding
		1692	requests.
		1693
1264	Example: Install an Event watcher that automatically calls	1694	Example: Install an Event watcher that automatically calls
1265	IO::AIO::poll_cb with high priority (more examples can be found in the	1695	IO::AIO::poll_cb with high priority (more examples can be found in the
1266	SYNOPSIS section, at the top of this document):	1696	SYNOPSIS section, at the top of this document):
1267		1697
1268	Event->io (fd => IO::AIO::poll_fileno,	1698	Event->io (fd => IO::AIO::poll_fileno,
1269	poll => 'r', async => 1,	1699	poll => 'r', async => 1,
1270	cb => \&IO::AIO::poll_cb);	1700	cb => \&IO::AIO::poll_cb);
		1701
		1702	=item IO::AIO::poll_wait
		1703
		1704	If there are any outstanding requests and none of them in the result
		1705	phase, wait till the result filehandle becomes ready for reading (simply
		1706	does a C<select> on the filehandle. This is useful if you want to
		1707	synchronously wait for some requests to finish).
		1708
		1709	See C<nreqs> for an example.
		1710
		1711	=item IO::AIO::poll
		1712
		1713	Waits until some requests have been handled.
		1714
		1715	Returns the number of requests processed, but is otherwise strictly
		1716	equivalent to:
		1717
		1718	IO::AIO::poll_wait, IO::AIO::poll_cb
		1719
		1720	=item IO::AIO::flush
		1721
		1722	Wait till all outstanding AIO requests have been handled.
		1723
		1724	Strictly equivalent to:
		1725
		1726	IO::AIO::poll_wait, IO::AIO::poll_cb
		1727	while IO::AIO::nreqs;
1271		1728
1272	=item IO::AIO::max_poll_reqs $nreqs	1729	=item IO::AIO::max_poll_reqs $nreqs
1273		1730
1274	=item IO::AIO::max_poll_time $seconds	1731	=item IO::AIO::max_poll_time $seconds
1275		1732
…		…
1300	# use a low priority so other tasks have priority	1757	# use a low priority so other tasks have priority
1301	Event->io (fd => IO::AIO::poll_fileno,	1758	Event->io (fd => IO::AIO::poll_fileno,
1302	poll => 'r', nice => 1,	1759	poll => 'r', nice => 1,
1303	cb => &IO::AIO::poll_cb);	1760	cb => &IO::AIO::poll_cb);
1304		1761
1305	=item IO::AIO::poll_wait
1306
1307	If there are any outstanding requests and none of them in the result
1308	phase, wait till the result filehandle becomes ready for reading (simply
1309	does a C<select> on the filehandle. This is useful if you want to
1310	synchronously wait for some requests to finish).
1311
1312	See C<nreqs> for an example.
1313
1314	=item IO::AIO::poll
1315
1316	Waits until some requests have been handled.
1317
1318	Returns the number of requests processed, but is otherwise strictly
1319	equivalent to:
1320
1321	IO::AIO::poll_wait, IO::AIO::poll_cb
1322
1323	=item IO::AIO::flush
1324
1325	Wait till all outstanding AIO requests have been handled.
1326
1327	Strictly equivalent to:
1328
1329	IO::AIO::poll_wait, IO::AIO::poll_cb
1330	while IO::AIO::nreqs;
1331
1332	=back	1762	=back
1333		1763
1334	=head3 CONTROLLING THE NUMBER OF THREADS	1764	=head3 CONTROLLING THE NUMBER OF THREADS
1335		1765
1336	=over	1766	=over
…		…
1369		1799
1370	Under normal circumstances you don't need to call this function.	1800	Under normal circumstances you don't need to call this function.
1371		1801
1372	=item IO::AIO::max_idle $nthreads	1802	=item IO::AIO::max_idle $nthreads
1373		1803
1374	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1804	Limit the number of threads (default: 4) that are allowed to idle
1375	threads that did not get a request to process within 10 seconds). That	1805	(i.e., threads that did not get a request to process within the idle
1376	means if a thread becomes idle while C<$nthreads> other threads are also	1806	timeout (default: 10 seconds). That means if a thread becomes idle while
1377	idle, it will free its resources and exit.	1807	C<$nthreads> other threads are also idle, it will free its resources and
		1808	exit.
1378		1809
1379	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1810	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1380	to allow for extremely high load situations, but want to free resources	1811	to allow for extremely high load situations, but want to free resources
1381	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1812	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1382		1813
1383	The default is probably ok in most situations, especially if thread	1814	The default is probably ok in most situations, especially if thread
1384	creation is fast. If thread creation is very slow on your system you might	1815	creation is fast. If thread creation is very slow on your system you might
1385	want to use larger values.	1816	want to use larger values.
1386		1817
		1818	=item IO::AIO::idle_timeout $seconds
		1819
		1820	Sets the minimum idle timeout (default 10) after which worker threads are
		1821	allowed to exit. SEe C<IO::AIO::max_idle>.
		1822
1387	=item IO::AIO::max_outstanding $maxreqs	1823	=item IO::AIO::max_outstanding $maxreqs
		1824
		1825	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1826	you do queue up more than this number of requests, the next call to
		1827	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1828	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1829	longer exceeded.
		1830
		1831	In other words, this setting does not enforce a queue limit, but can be
		1832	used to make poll functions block if the limit is exceeded.
1388		1833
1389	This is a very bad function to use in interactive programs because it	1834	This is a very bad function to use in interactive programs because it
1390	blocks, and a bad way to reduce concurrency because it is inexact: Better	1835	blocks, and a bad way to reduce concurrency because it is inexact: Better
1391	use an C<aio_group> together with a feed callback.	1836	use an C<aio_group> together with a feed callback.
1392		1837
1393	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1838	It's main use is in scripts without an event loop - when you want to stat
1394	do queue up more than this number of requests, the next call to the	1839	a lot of files, you can write somehting like this:
1395	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1396	function will block until the limit is no longer exceeded.
1397		1840
1398	The default value is very large, so there is no practical limit on the	1841	IO::AIO::max_outstanding 32;
1399	number of outstanding requests.
1400		1842
1401	You can still queue as many requests as you want. Therefore,	1843	for my $path (...) {
1402	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1844	aio_stat $path , ...;
1403	as a stop gap to shield against fatal memory overflow (with large values).	1845	IO::AIO::poll_cb;
		1846	}
		1847
		1848	IO::AIO::flush;
		1849
		1850	The call to C<poll_cb> inside the loop will normally return instantly, but
		1851	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1852	some requests have been handled. This keeps the loop from pushing a large
		1853	number of C<aio_stat> requests onto the queue.
		1854
		1855	The default value for C<max_outstanding> is very large, so there is no
		1856	practical limit on the number of outstanding requests.
1404		1857
1405	=back	1858	=back
1406		1859
1407	=head3 STATISTICAL INFORMATION	1860	=head3 STATISTICAL INFORMATION
1408		1861
…		…
1446		1899
1447	Returns the number of bytes copied, or C<-1> on error.	1900	Returns the number of bytes copied, or C<-1> on error.
1448		1901
1449	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1902	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1450		1903
1451	Simply calls the C<posix_fadvise> function (see it's	1904	Simply calls the C<posix_fadvise> function (see its
1452	manpage for details). The following advice constants are	1905	manpage for details). The following advice constants are
1453	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1906	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1454	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1907	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1455	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	1908	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1456		1909
1457	On systems that do not implement C<posix_fadvise>, this function returns	1910	On systems that do not implement C<posix_fadvise>, this function returns
1458	ENOSYS, otherwise the return value of C<posix_fadvise>.	1911	ENOSYS, otherwise the return value of C<posix_fadvise>.
1459		1912
		1913	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1914
		1915	Simply calls the C<posix_madvise> function (see its
		1916	manpage for details). The following advice constants are
		1917	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1918	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1919
		1920	On systems that do not implement C<posix_madvise>, this function returns
		1921	ENOSYS, otherwise the return value of C<posix_madvise>.
		1922
		1923	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1924
		1925	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1926	$scalar (see its manpage for details). The following protect
		1927	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1928	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1929
		1930	On systems that do not implement C<mprotect>, this function returns
		1931	ENOSYS, otherwise the return value of C<mprotect>.
		1932
		1933	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1934
		1935	Memory-maps a file (or anonymous memory range) and attaches it to the
		1936	given C<$scalar>, which will act like a string scalar. Returns true on
		1937	success, and false otherwise.
		1938
		1939	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1940	change the string length, and most read-only operations such as copying it
		1941	or searching it with regexes and so on.
		1942
		1943	Anything else is unsafe and will, at best, result in memory leaks.
		1944
		1945	The memory map associated with the C<$scalar> is automatically removed
		1946	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1947	C<IO::AIO::munmap> functions are called.
		1948
		1949	This calls the C<mmap>(2) function internally. See your system's manual
		1950	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1951
		1952	The C<$length> must be larger than zero and smaller than the actual
		1953	filesize.
		1954
		1955	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1956	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1957
		1958	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1959	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1960	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1961	(which is set to C<MAP_ANON> if your system only provides this
		1962	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1963	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1964	C<IO::AIO::MAP_NONBLOCK>
		1965
		1966	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1967
		1968	C<$offset> is the offset from the start of the file - it generally must be
		1969	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1970
		1971	Example:
		1972
		1973	use Digest::MD5;
		1974	use IO::AIO;
		1975
		1976	open my $fh, "<verybigfile"
		1977	or die "$!";
		1978
		1979	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1980	or die "verybigfile: $!";
		1981
		1982	my $fast_md5 = md5 $data;
		1983
		1984	=item IO::AIO::munmap $scalar
		1985
		1986	Removes a previous mmap and undefines the C<$scalar>.
		1987
		1988	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1989
		1990	Calls the C<munlock> function, undoing the effects of a previous
		1991	C<aio_mlock> call (see its description for details).
		1992
		1993	=item IO::AIO::munlockall
		1994
		1995	Calls the C<munlockall> function.
		1996
		1997	On systems that do not implement C<munlockall>, this function returns
		1998	ENOSYS, otherwise the return value of C<munlockall>.
		1999
		2000	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2001
		2002	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2003	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2004	should be the file offset.
		2005
		2006	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2007	silently corrupt the data in this case.
		2008
		2009	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2010	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2011	C<IO::AIO::SPLICE_F_GIFT>.
		2012
		2013	See the C<splice(2)> manpage for details.
		2014
		2015	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2016
		2017	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
		2018	description for C<IO::AIO::splice> above for details.
		2019
1460	=back	2020	=back
1461		2021
1462	=cut	2022	=cut
1463		2023
1464	min_parallel 8;	2024	min_parallel 8;
1465		2025
1466	END { flush }	2026	END { flush }
1467		2027
1468	1;	2028	1;
1469		2029
		2030	=head1 EVENT LOOP INTEGRATION
		2031
		2032	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		2033	automatically into many event loops:
		2034
		2035	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		2036	use AnyEvent::AIO;
		2037
		2038	You can also integrate IO::AIO manually into many event loops, here are
		2039	some examples of how to do this:
		2040
		2041	# EV integration
		2042	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		2043
		2044	# Event integration
		2045	Event->io (fd => IO::AIO::poll_fileno,
		2046	poll => 'r',
		2047	cb => \&IO::AIO::poll_cb);
		2048
		2049	# Glib/Gtk2 integration
		2050	add_watch Glib::IO IO::AIO::poll_fileno,
		2051	in => sub { IO::AIO::poll_cb; 1 };
		2052
		2053	# Tk integration
		2054	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		2055	readable => \&IO::AIO::poll_cb);
		2056
		2057	# Danga::Socket integration
		2058	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		2059	\&IO::AIO::poll_cb);
		2060
1470	=head2 FORK BEHAVIOUR	2061	=head2 FORK BEHAVIOUR
1471		2062
1472	This module should do "the right thing" when the process using it forks:	2063	Usage of pthreads in a program changes the semantics of fork
		2064	considerably. Specifically, only async-safe functions can be called after
		2065	fork. Perl doesn't know about this, so in general, you cannot call fork
		2066	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2067	pthreads, so this applies, but many other extensions and (for inexplicable
		2068	reasons) perl itself often is linked against pthreads, so this limitation
		2069	applies to quite a lot of perls.
1473		2070
1474	Before the fork, IO::AIO enters a quiescent state where no requests	2071	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1475	can be added in other threads and no results will be processed. After	2072	only works in the process that loaded it. Forking is fully supported, but
1476	the fork the parent simply leaves the quiescent state and continues	2073	using IO::AIO in the child is not.
1477	request/result processing, while the child frees the request/result queue
1478	(so that the requests started before the fork will only be handled in the
1479	parent). Threads will be started on demand until the limit set in the
1480	parent process has been reached again.
1481		2074
1482	In short: the parent will, after a short pause, continue as if fork had	2075	You might get around by not I<using> IO::AIO before (or after)
1483	not been called, while the child will act as if IO::AIO has not been used	2076	forking. You could also try to call the L<IO::AIO::reinit> function in the
1484	yet.	2077	child:
		2078
		2079	=over 4
		2080
		2081	=item IO::AIO::reinit
		2082
		2083	Abandons all current requests and I/O threads and simply reinitialises all
		2084	data structures. This is not an operation supported by any standards, but
		2085	happens to work on GNU/Linux and some newer BSD systems.
		2086
		2087	The only reasonable use for this function is to call it after forking, if
		2088	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2089	the process will result in undefined behaviour. Calling it at any time
		2090	will also result in any undefined (by POSIX) behaviour.
		2091
		2092	=back
1485		2093
1486	=head2 MEMORY USAGE	2094	=head2 MEMORY USAGE
1487		2095
1488	Per-request usage:	2096	Per-request usage:
1489		2097

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC vs. Revision 1.233 by root, Mon Aug 13 01:01:04 2012 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC vs.
Revision 1.233 by root, Mon Aug 13 01:01:04 2012 UTC