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Revision 1.113 by root, Thu Sep 20 14:06:21 2007 UTC vs.
Revision 1.191 by root, Thu May 19 23:57:12 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 aio_truncate);	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
332	like the syscall).	398	error, just like the syscall).
		399
		400	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		401	offset plus the actual number of bytes read.
333		402
334	If C<$offset> is undefined, then the current file descriptor offset will	403	If C<$offset> is undefined, then the current file descriptor offset will
335	be used (and updated), otherwise the file descriptor offset will not be	404	be used (and updated), otherwise the file descriptor offset will not be
336	changed by these calls.	405	changed by these calls.
337		406
338	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.	407	If C<$length> is undefined in C<aio_write>, use the remaining length of
		408	C<$data>.
339		409
340	If C<$dataoffset> is less than zero, it will be counted from the end of	410	If C<$dataoffset> is less than zero, it will be counted from the end of
341	C<$data>.	411	C<$data>.
342		412
343	The C<$data> scalar I<MUST NOT> be modified in any way while the request	413	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
359	reading at byte offset C<$in_offset>, and starts writing at the current	429	reading at byte offset C<$in_offset>, and starts writing at the current
360	file offset of C<$out_fh>. Because of that, it is not safe to issue more	430	file offset of C<$out_fh>. Because of that, it is not safe to issue more
361	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	431	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
362	other.	432	other.
363		433
		434	Please note that C<aio_sendfile> can read more bytes from C<$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
364	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
365	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
366	socket, and C<$in_fh> should refer to mmap'able file.	452	socket, and C<$in_fh> should refer to an mmap'able file.
367		453
368	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>,
369	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
370	regardless of the limitations of the operating system.	457	filehandle regardless of the limitations of the operating system.
371
372	Please note, however, that C<aio_sendfile> can read more bytes from
373	C<$in_fh> than are written, and there is no way to find out how many
374	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
375	provides the number of bytes written to C<$out_fh>. Only if the result
376	value equals C<$length> one can assume that C<$length> bytes have been
377	read.
378		458
379		459
380	=item aio_readahead $fh,$offset,$length, $callback->($retval)	460	=item aio_readahead $fh,$offset,$length, $callback->($retval)
381		461
382	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
…		…
405		485
406	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
407	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
408	unless perl itself is compiled with large file support.	488	unless perl itself is compiled with large file support.
409		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
410	Example: Print the length of F</etc/passwd>:	499	Example: Print the length of F</etc/passwd>:
411		500
412	aio_stat "/etc/passwd", sub {	501	aio_stat "/etc/passwd", sub {
413	$_[0] and die "stat failed: $!";	502	$_[0] and die "stat failed: $!";
414	print "size is ", -s _, "\n";	503	print "size is ", -s _, "\n";
415	};	504	};
416		505
417		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
418	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	552	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
419		553
420	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
421	and $mtime being undef). Fractional times are supported if the underlying	555	and $mtime being undef). Fractional times are supported if the underlying
422	syscalls support them.	556	syscalls support them.
…		…
470		604
471	The only (POSIX-) portable way of calling this function is:	605	The only (POSIX-) portable way of calling this function is:
472		606
473	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	607	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
474		608
		609	See C<aio_stat> for info about some potentially helpful extra constants
		610	and functions.
475		611
476	=item aio_link $srcpath, $dstpath, $callback->($status)	612	=item aio_link $srcpath, $dstpath, $callback->($status)
477		613
478	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
479	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.
…		…
515		651
516	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
517	directory (i.e. opendir + readdir + closedir). The entries will not be	653	directory (i.e. opendir + readdir + closedir). The entries will not be
518	sorted, and will B<NOT> include the C<.> and C<..> entries.	654	sorted, and will B<NOT> include the C<.> and C<..> entries.
519		655
520	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
521	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<$inode> is the inode number (which might not be exact on systems with 64
		691	bit inode numbers and 32 bit perls). This field has unspecified content on
		692	systems that do not deliver the inode information.
		693
		694	=item IO::AIO::READDIR_DIRS_FIRST
		695
		696	When this flag is set, then the names will be returned in an order where
		697	likely directories come first. This is useful when you need to quickly
		698	find directories, or you want to find all directories while avoiding to
		699	stat() each entry.
		700
		701	If the system returns type information in readdir, then this is used
		702	to find directories directly. Otherwise, likely directories are files
		703	beginning with ".", or otherwise files with no dots, of which files with
		704	short names are tried first.
		705
		706	=item IO::AIO::READDIR_STAT_ORDER
		707
		708	When this flag is set, then the names will be returned in an order
		709	suitable for stat()'ing each one. That is, when you plan to stat()
		710	all files in the given directory, then the returned order will likely
		711	be fastest.
		712
		713	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		714	the likely dirs come first, resulting in a less optimal stat order.
		715
		716	=item IO::AIO::READDIR_FOUND_UNKNOWN
		717
		718	This flag should not be set when calling C<aio_readdirx>. Instead, it
		719	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		720	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		721	C<$type>'s are known, which can be used to speed up some algorithms.
		722
		723	=back
522		724
523		725
524	=item aio_load $path, $data, $callback->($status)	726	=item aio_load $path, $data, $callback->($status)
525		727
526	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
527	memory. Status is the same as with aio_read.	729	memory. Status is the same as with aio_read.
528		730
529	=cut	731	=cut
530		732
531	sub aio_load($$;$) {	733	sub aio_load($$;$) {
532	aio_block {
533	my ($path, undef, $cb) = @_;	734	my ($path, undef, $cb) = @_;
534	my $data = \$_[1];	735	my $data = \$_[1];
535		736
536	my $pri = aioreq_pri;	737	my $pri = aioreq_pri;
537	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);
538		744
539	aioreq_pri $pri;	745	aioreq_pri $pri;
540	add $grp aio_open $path, O_RDONLY, 0, sub {
541	my $fh = shift
542	or return $grp->result (-1);
543
544	aioreq_pri $pri;
545	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	746	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
546	$grp->result ($_[0]);	747	$grp->result ($_[0]);
547	};
548	};	748	};
549
550	$grp
551	}	749	};
		750
		751	$grp
552	}	752	}
553		753
554	=item aio_copy $srcpath, $dstpath, $callback->($status)	754	=item aio_copy $srcpath, $dstpath, $callback->($status)
555		755
556	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
557	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
558	the C<0> (error) or C<-1> ok.	758	a status of C<0> (ok) or C<-1> (error, see C<$!>).
559		759
560	This is a composite request that it creates the destination file with	760	This is a composite request that creates the destination file with
561	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
562	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	762	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
563	uid/gid, in that order.	763	uid/gid, in that order.
564		764
565	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
…		…
567	errors are being ignored.	767	errors are being ignored.
568		768
569	=cut	769	=cut
570		770
571	sub aio_copy($$;$) {	771	sub aio_copy($$;$) {
572	aio_block {
573	my ($src, $dst, $cb) = @_;	772	my ($src, $dst, $cb) = @_;
574		773
575	my $pri = aioreq_pri;	774	my $pri = aioreq_pri;
576	my $grp = aio_group $cb;	775	my $grp = aio_group $cb;
577		776
578	aioreq_pri $pri;	777	aioreq_pri $pri;
579	add $grp aio_open $src, O_RDONLY, 0, sub {	778	add $grp aio_open $src, O_RDONLY, 0, sub {
580	if (my $src_fh = $_[0]) {	779	if (my $src_fh = $_[0]) {
581	my @stat = stat $src_fh;	780	my @stat = stat $src_fh; # hmm, might block over nfs?
582		781
583	aioreq_pri $pri;	782	aioreq_pri $pri;
584	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 {
585	if (my $dst_fh = $_[0]) {	784	if (my $dst_fh = $_[0]) {
586	aioreq_pri $pri;	785	aioreq_pri $pri;
587	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	786	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
588	if ($_[0] == $stat[7]) {	787	if ($_[0] == $stat[7]) {
589	$grp->result (0);	788	$grp->result (0);
590	close $src_fh;	789	close $src_fh;
591		790
592	# those should not normally block. should. should.
593	utime $stat[8], $stat[9], $dst;
594	chmod $stat[2] & 07777, $dst_fh;
595	chown $stat[4], $stat[5], $dst_fh;
596	close $dst_fh;
597	} else {	791	my $ch = sub {
598	$grp->result (-1);
599	close $src_fh;
600	close $dst_fh;
601
602	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;
603	add $grp aio_unlink $dst;	797	add $grp aio_close $dst_fh;
		798	}
		799	};
604	}	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;
605	};	818	}
606	} else {
607	$grp->result (-1);
608	}	819	};
		820	} else {
		821	$grp->result (-1);
609	},	822	}
610
611	} else {
612	$grp->result (-1);
613	}	823	},
		824
		825	} else {
		826	$grp->result (-1);
614	};	827	}
615
616	$grp
617	}	828	};
		829
		830	$grp
618	}	831	}
619		832
620	=item aio_move $srcpath, $dstpath, $callback->($status)	833	=item aio_move $srcpath, $dstpath, $callback->($status)
621		834
622	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
623	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
624	the C<0> (error) or C<-1> ok.	837	a status of C<0> (ok) or C<-1> (error, see C<$!>).
625		838
626	This is a composite request that tries to rename(2) the file first. If	839	This is a composite request that tries to rename(2) the file first; if
627	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	840	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
628	that is successful, unlinking the C<$srcpath>.	841	that is successful, unlinks the C<$srcpath>.
629		842
630	=cut	843	=cut
631		844
632	sub aio_move($$;$) {	845	sub aio_move($$;$) {
633	aio_block {
634	my ($src, $dst, $cb) = @_;	846	my ($src, $dst, $cb) = @_;
635		847
636	my $pri = aioreq_pri;	848	my $pri = aioreq_pri;
637	my $grp = aio_group $cb;	849	my $grp = aio_group $cb;
638		850
639	aioreq_pri $pri;	851	aioreq_pri $pri;
640	add $grp aio_rename $src, $dst, sub {	852	add $grp aio_rename $src, $dst, sub {
641	if ($_[0] && $! == EXDEV) {	853	if ($_[0] && $! == EXDEV) {
642	aioreq_pri $pri;	854	aioreq_pri $pri;
643	add $grp aio_copy $src, $dst, sub {	855	add $grp aio_copy $src, $dst, sub {
644	$grp->result ($_[0]);
645
646	if (!$_[0]) {
647	aioreq_pri $pri;
648	add $grp aio_unlink $src;
649	}
650	};
651	} else {
652	$grp->result ($_[0]);	856	$grp->result ($_[0]);
		857
		858	if (!$_[0]) {
		859	aioreq_pri $pri;
		860	add $grp aio_unlink $src;
		861	}
653	}	862	};
		863	} else {
		864	$grp->result ($_[0]);
654	};	865	}
655
656	$grp
657	}	866	};
		867
		868	$grp
658	}	869	}
659		870
660	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	871	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
661		872
662	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
…		…
682		893
683	Implementation notes.	894	Implementation notes.
684		895
685	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.
686		897
		898	If readdir returns file type information, then this is used directly to
		899	find directories.
		900
687	After reading the directory, the modification time, size etc. of the	901	Otherwise, after reading the directory, the modification time, size etc.
688	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
689	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
690	entries are directories (if >= 2). Otherwise, no knowledge of the number	904	how many entries are directories (if >= 2). Otherwise, no knowledge of the
691	of subdirectories will be assumed.	905	number of subdirectories will be assumed.
692		906
693	Then entries will be sorted into likely directories (everything without	907	Then entries will be sorted into likely directories a non-initial dot
694	a non-initial dot currently) and likely non-directories (everything	908	currently) and likely non-directories (see C<aio_readdirx>). Then every
695	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,
696	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
697	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
698	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
699	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
700	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.
701		916
702	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
703	rest of the entries is assumed to be non-directories.	918	rest of the entries is assumed to be non-directories.
704		919
705	This only works with certainty on POSIX (= UNIX) filesystems, which	920	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
710	directory counting heuristic.	925	directory counting heuristic.
711		926
712	=cut	927	=cut
713		928
714	sub aio_scandir($$;$) {	929	sub aio_scandir($$;$) {
715	aio_block {
716	my ($path, $maxreq, $cb) = @_;	930	my ($path, $maxreq, $cb) = @_;
717		931
718	my $pri = aioreq_pri;	932	my $pri = aioreq_pri;
719		933
720	my $grp = aio_group $cb;	934	my $grp = aio_group $cb;
721		935
722	$maxreq = 4 if $maxreq <= 0;	936	$maxreq = 4 if $maxreq <= 0;
723		937
724	# 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
725	aioreq_pri $pri;	946	aioreq_pri $pri;
726	add $grp aio_stat $path, sub {	947	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		948	my $entries = shift
727	return $grp->result () if $_[0];	949	or return $grp->result ();
728	my $now = time;
729	my $hash1 = join ":", (stat _)[0,1,3,7,9];
730		950
731	# read the directory entries	951	# stat the dir another time
732	aioreq_pri $pri;	952	aioreq_pri $pri;
733	add $grp aio_readdir $path, sub {
734	my $entries = shift
735	or return $grp->result ();
736
737	# stat the dir another time
738	aioreq_pri $pri;
739	add $grp aio_stat $path, sub {	953	add $grp aio_stat $path, sub {
740	my $hash2 = join ":", (stat _)[0,1,3,7,9];	954	my $hash2 = join ":", (stat _)[0,1,3,7,9];
741		955
742	my $ndirs;	956	my $ndirs;
743		957
744	# take the slow route if anything looks fishy	958	# take the slow route if anything looks fishy
745	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	959	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
746	$ndirs = -1;	960	$ndirs = -1;
747	} else {	961	} else {
748	# if nlink == 2, we are finished	962	# if nlink == 2, we are finished
749	# on non-posix-fs's, we rely on nlink < 2	963	# for non-posix-fs's, we rely on nlink < 2
750	$ndirs = (stat _)[3] - 2	964	$ndirs = (stat _)[3] - 2
751	or return $grp->result ([], $entries);	965	or return $grp->result ([], $entries);
752	}	966	}
753		967
754	# sort into likely dirs and likely nondirs
755	# dirs == files without ".", short entries first
756	$entries = [map $_->[0],
757	sort { $b->[1] cmp $a->[1] }
758	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
759	@$entries];
760
761	my (@dirs, @nondirs);	968	my (@dirs, @nondirs);
762		969
763	my $statgrp = add $grp aio_group sub {	970	my $statgrp = add $grp aio_group sub {
764	$grp->result (\@dirs, \@nondirs);	971	$grp->result (\@dirs, \@nondirs);
765	};	972	};
766		973
767	limit $statgrp $maxreq;	974	limit $statgrp $maxreq;
768	feed $statgrp sub {	975	feed $statgrp sub {
769	return unless @$entries;	976	return unless @$entries;
770	my $entry = pop @$entries;	977	my $entry = shift @$entries;
771		978
772	aioreq_pri $pri;	979	aioreq_pri $pri;
773	add $statgrp aio_stat "$path/$entry/.", sub {	980	add $statgrp aio_stat "$path/$entry/.", sub {
774	if ($_[0] < 0) {	981	if ($_[0] < 0) {
775	push @nondirs, $entry;	982	push @nondirs, $entry;
776	} else {	983	} else {
777	# need to check for real directory	984	# need to check for real directory
778	aioreq_pri $pri;	985	aioreq_pri $pri;
779	add $statgrp aio_lstat "$path/$entry", sub {	986	add $statgrp aio_lstat "$path/$entry", sub {
780	if (-d _) {	987	if (-d _) {
781	push @dirs, $entry;	988	push @dirs, $entry;
782		989
783	unless (--$ndirs) {	990	unless (--$ndirs) {
784	push @nondirs, @$entries;	991	push @nondirs, @$entries;
785	feed $statgrp;	992	feed $statgrp;
786	}
787	} else {
788	push @nondirs, $entry;
789	}	993	}
		994	} else {
		995	push @nondirs, $entry;
790	}	996	}
791	}	997	}
792	};	998	}
793	};	999	};
794	};	1000	};
795	};	1001	};
796	};	1002	};
797
798	$grp
799	}	1003	};
		1004
		1005	$grp
800	}	1006	}
801		1007
802	=item aio_rmtree $path, $callback->($status)	1008	=item aio_rmtree $path, $callback->($status)
803		1009
804	Delete a directory tree starting (and including) C<$path>, return the	1010	Delete a directory tree starting (and including) C<$path>, return the
…		…
808		1014
809	=cut	1015	=cut
810		1016
811	sub aio_rmtree;	1017	sub aio_rmtree;
812	sub aio_rmtree($;$) {	1018	sub aio_rmtree($;$) {
813	aio_block {
814	my ($path, $cb) = @_;	1019	my ($path, $cb) = @_;
815		1020
816	my $pri = aioreq_pri;	1021	my $pri = aioreq_pri;
817	my $grp = aio_group $cb;	1022	my $grp = aio_group $cb;
818		1023
819	aioreq_pri $pri;	1024	aioreq_pri $pri;
820	add $grp aio_scandir $path, 0, sub {	1025	add $grp aio_scandir $path, 0, sub {
821	my ($dirs, $nondirs) = @_;	1026	my ($dirs, $nondirs) = @_;
822		1027
823	my $dirgrp = aio_group sub {	1028	my $dirgrp = aio_group sub {
824	add $grp aio_rmdir $path, sub {	1029	add $grp aio_rmdir $path, sub {
825	$grp->result ($_[0]);	1030	$grp->result ($_[0]);
826	};
827	};	1031	};
828
829	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
830	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
831
832	add $grp $dirgrp;
833	};	1032	};
834		1033
835	$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;
836	}	1038	};
		1039
		1040	$grp
837	}	1041	}
		1042
		1043	=item aio_sync $callback->($status)
		1044
		1045	Asynchronously call sync and call the callback when finished.
838		1046
839	=item aio_fsync $fh, $callback->($status)	1047	=item aio_fsync $fh, $callback->($status)
840		1048
841	Asynchronously call fsync on the given filehandle and call the callback	1049	Asynchronously call fsync on the given filehandle and call the callback
842	with the fsync result code.	1050	with the fsync result code.
…		…
846	Asynchronously call fdatasync on the given filehandle and call the	1054	Asynchronously call fdatasync on the given filehandle and call the
847	callback with the fdatasync result code.	1055	callback with the fdatasync result code.
848		1056
849	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
850	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;
851		1178
852	=item aio_group $callback->(...)	1179	=item aio_group $callback->(...)
853		1180
854	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
855	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
…		…
905	=item cancel $req	1232	=item cancel $req
906		1233
907	Cancels the request, if possible. Has the effect of skipping execution	1234	Cancels the request, if possible. Has the effect of skipping execution
908	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
909	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
910	untouched. That means that requests that currently execute will not be	1237	untouched (with the exception of readdir). That means that requests that
911	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.
912		1240
913	=item cb $req $callback->(...)	1241	=item cb $req $callback->(...)
914		1242
915	Replace (or simply set) the callback registered to the request.	1243	Replace (or simply set) the callback registered to the request.
916		1244
…		…
967	Their lifetime, simplified, looks like this: when they are empty, they	1295	Their lifetime, simplified, looks like this: when they are empty, they
968	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
969	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
970	exist.	1298	exist.
971		1299
972	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
973	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
974	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
975	itself finish.	1303	further requests to the group. And only when all those requests have
		1304	finished will the the group itself finish.
976		1305
977	=over 4	1306	=over 4
978		1307
979	=item add $grp ...	1308	=item add $grp ...
980		1309
…		…
989	=item $grp->cancel_subs	1318	=item $grp->cancel_subs
990		1319
991	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
992	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.
993		1322
		1323	The group request will finish normally (you cannot add requests to the
		1324	group).
		1325
994	=item $grp->result (...)	1326	=item $grp->result (...)
995		1327
996	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
997	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
998	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,
999	no argument will be passed and errno is zero.	1331	no argument will be passed and errno is zero.
1000		1332
1001	=item $grp->errno ([$errno])	1333	=item $grp->errno ([$errno])
1002		1334
…		…
1013	=item feed $grp $callback->($grp)	1345	=item feed $grp $callback->($grp)
1014		1346
1015	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
1016	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,
1017	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,
1018	this might starve other requests for a potentially long time. For	1350	this might starve other requests for a potentially long time. For example,
1019	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,
1020	requests, delaying any later requests for a long time.	1352	delaying any later requests for a long time.
1021		1353
1022	To avoid this, and allow incremental generation of requests, you can	1354	To avoid this, and allow incremental generation of requests, you can
1023	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
1024	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>,
1025	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
…		…
1029	not impose any limits).	1361	not impose any limits).
1030		1362
1031	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
1032	automatically removed from the group.	1364	automatically removed from the group.
1033		1365
1034	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.
1035		1368
1036	Example:	1369	Example:
1037		1370
1038	# 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:
1039		1372
…		…
1051	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
1052	the group contains less than this many requests.	1385	the group contains less than this many requests.
1053		1386
1054	Setting the limit to C<0> will pause the feeding process.	1387	Setting the limit to C<0> will pause the feeding process.
1055		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
1056	=back	1392	=back
1057		1393
1058	=head2 SUPPORT FUNCTIONS	1394	=head2 SUPPORT FUNCTIONS
1059		1395
1060	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1396	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1062	=over 4	1398	=over 4
1063		1399
1064	=item $fileno = IO::AIO::poll_fileno	1400	=item $fileno = IO::AIO::poll_fileno
1065		1401
1066	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
1067	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,
1068	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
1069	to call C<poll_cb> to check the results.	1405	you have to call C<poll_cb> to check the results.
1070		1406
1071	See C<poll_cb> for an example.	1407	See C<poll_cb> for an example.
1072		1408
1073	=item IO::AIO::poll_cb	1409	=item IO::AIO::poll_cb
1074		1410
1075	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
1076	regularly. Returns the number of events processed. Returns immediately	1412	this regularly. Returns C<0> if all events could be processed (or there
1077	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
1078	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>.
1079		1417
1080	If not all requests were processed for whatever reason, the filehandle	1418	If not all requests were processed for whatever reason, the filehandle
1081	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.
1082		1421
1083	Example: Install an Event watcher that automatically calls	1422	Example: Install an Event watcher that automatically calls
1084	IO::AIO::poll_cb with high priority:	1423	IO::AIO::poll_cb with high priority (more examples can be found in the
		1424	SYNOPSIS section, at the top of this document):
1085		1425
1086	Event->io (fd => IO::AIO::poll_fileno,	1426	Event->io (fd => IO::AIO::poll_fileno,
1087	poll => 'r', async => 1,	1427	poll => 'r', async => 1,
1088	cb => \&IO::AIO::poll_cb);	1428	cb => \&IO::AIO::poll_cb);
		1429
		1430	=item IO::AIO::poll_wait
		1431
		1432	If there are any outstanding requests and none of them in the result
		1433	phase, wait till the result filehandle becomes ready for reading (simply
		1434	does a C<select> on the filehandle. This is useful if you want to
		1435	synchronously wait for some requests to finish).
		1436
		1437	See C<nreqs> for an example.
		1438
		1439	=item IO::AIO::poll
		1440
		1441	Waits until some requests have been handled.
		1442
		1443	Returns the number of requests processed, but is otherwise strictly
		1444	equivalent to:
		1445
		1446	IO::AIO::poll_wait, IO::AIO::poll_cb
		1447
		1448	=item IO::AIO::flush
		1449
		1450	Wait till all outstanding AIO requests have been handled.
		1451
		1452	Strictly equivalent to:
		1453
		1454	IO::AIO::poll_wait, IO::AIO::poll_cb
		1455	while IO::AIO::nreqs;
1089		1456
1090	=item IO::AIO::max_poll_reqs $nreqs	1457	=item IO::AIO::max_poll_reqs $nreqs
1091		1458
1092	=item IO::AIO::max_poll_time $seconds	1459	=item IO::AIO::max_poll_time $seconds
1093		1460
…		…
1118	# use a low priority so other tasks have priority	1485	# use a low priority so other tasks have priority
1119	Event->io (fd => IO::AIO::poll_fileno,	1486	Event->io (fd => IO::AIO::poll_fileno,
1120	poll => 'r', nice => 1,	1487	poll => 'r', nice => 1,
1121	cb => &IO::AIO::poll_cb);	1488	cb => &IO::AIO::poll_cb);
1122		1489
1123	=item IO::AIO::poll_wait
1124
1125	If there are any outstanding requests and none of them in the result
1126	phase, wait till the result filehandle becomes ready for reading (simply
1127	does a C<select> on the filehandle. This is useful if you want to
1128	synchronously wait for some requests to finish).
1129
1130	See C<nreqs> for an example.
1131
1132	=item IO::AIO::poll
1133
1134	Waits until some requests have been handled.
1135
1136	Returns the number of requests processed, but is otherwise strictly
1137	equivalent to:
1138
1139	IO::AIO::poll_wait, IO::AIO::poll_cb
1140
1141	=item IO::AIO::flush
1142
1143	Wait till all outstanding AIO requests have been handled.
1144
1145	Strictly equivalent to:
1146
1147	IO::AIO::poll_wait, IO::AIO::poll_cb
1148	while IO::AIO::nreqs;
1149
1150	=back	1490	=back
1151		1491
1152	=head3 CONTROLLING THE NUMBER OF THREADS	1492	=head3 CONTROLLING THE NUMBER OF THREADS
1153		1493
1154	=over	1494	=over
…		…
1187		1527
1188	Under normal circumstances you don't need to call this function.	1528	Under normal circumstances you don't need to call this function.
1189		1529
1190	=item IO::AIO::max_idle $nthreads	1530	=item IO::AIO::max_idle $nthreads
1191		1531
1192	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1532	Limit the number of threads (default: 4) that are allowed to idle
1193	threads that did not get a request to process within 10 seconds). That	1533	(i.e., threads that did not get a request to process within the idle
1194	means if a thread becomes idle while C<$nthreads> other threads are also	1534	timeout (default: 10 seconds). That means if a thread becomes idle while
1195	idle, it will free its resources and exit.	1535	C<$nthreads> other threads are also idle, it will free its resources and
		1536	exit.
1196		1537
1197	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1538	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1198	to allow for extremely high load situations, but want to free resources	1539	to allow for extremely high load situations, but want to free resources
1199	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1540	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1200		1541
1201	The default is probably ok in most situations, especially if thread	1542	The default is probably ok in most situations, especially if thread
1202	creation is fast. If thread creation is very slow on your system you might	1543	creation is fast. If thread creation is very slow on your system you might
1203	want to use larger values.	1544	want to use larger values.
1204		1545
		1546	=item IO::AIO::idle_timeout $seconds
		1547
		1548	Sets the minimum idle timeout (default 10) after which worker threads are
		1549	allowed to exit. SEe C<IO::AIO::max_idle>.
		1550
1205	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1551	=item IO::AIO::max_outstanding $maxreqs
1206		1552
1207	This is a very bad function to use in interactive programs because it	1553	This is a very bad function to use in interactive programs because it
1208	blocks, and a bad way to reduce concurrency because it is inexact: Better	1554	blocks, and a bad way to reduce concurrency because it is inexact: Better
1209	use an C<aio_group> together with a feed callback.	1555	use an C<aio_group> together with a feed callback.
1210		1556
…		…
1215		1561
1216	The default value is very large, so there is no practical limit on the	1562	The default value is very large, so there is no practical limit on the
1217	number of outstanding requests.	1563	number of outstanding requests.
1218		1564
1219	You can still queue as many requests as you want. Therefore,	1565	You can still queue as many requests as you want. Therefore,
1220	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1566	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1221	as a stop gap to shield against fatal memory overflow (with large values).	1567	as a stop gap to shield against fatal memory overflow (with large values).
1222		1568
1223	=back	1569	=back
1224		1570
1225	=head3 STATISTICAL INFORMATION	1571	=head3 STATISTICAL INFORMATION
…		…
1246	Returns the number of requests currently in the pending state (executed,	1592	Returns the number of requests currently in the pending state (executed,
1247	but not yet processed by poll_cb).	1593	but not yet processed by poll_cb).
1248		1594
1249	=back	1595	=back
1250		1596
		1597	=head3 MISCELLANEOUS FUNCTIONS
		1598
		1599	IO::AIO implements some functions that might be useful, but are not
		1600	asynchronous.
		1601
		1602	=over 4
		1603
		1604	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1605
		1606	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1607	but is blocking (this makes most sense if you know the input data is
		1608	likely cached already and the output filehandle is set to non-blocking
		1609	operations).
		1610
		1611	Returns the number of bytes copied, or C<-1> on error.
		1612
		1613	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1614
		1615	Simply calls the C<posix_fadvise> function (see its
		1616	manpage for details). The following advice constants are
		1617	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1618	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1619	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1620
		1621	On systems that do not implement C<posix_fadvise>, this function returns
		1622	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1623
		1624	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1625
		1626	Simply calls the C<posix_madvise> function (see its
		1627	manpage for details). The following advice constants are
		1628	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1629	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1630
		1631	On systems that do not implement C<posix_madvise>, this function returns
		1632	ENOSYS, otherwise the return value of C<posix_madvise>.
		1633
		1634	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1635
		1636	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1637	$scalar (see its manpage for details). The following protect
		1638	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1639	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1640
		1641	On systems that do not implement C<mprotect>, this function returns
		1642	ENOSYS, otherwise the return value of C<mprotect>.
		1643
		1644	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1645
		1646	Memory-maps a file (or anonymous memory range) and attaches it to the
		1647	given C<$scalar>, which will act like a string scalar.
		1648
		1649	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1650	change the string length, and most read-only operations such as copying it
		1651	or searching it with regexes and so on.
		1652
		1653	Anything else is unsafe and will, at best, result in memory leaks.
		1654
		1655	The memory map associated with the C<$scalar> is automatically removed
		1656	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1657	C<IO::AIO::munmap> functions are called.
		1658
		1659	This calls the C<mmap>(2) function internally. See your system's manual
		1660	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1661
		1662	The C<$length> must be larger than zero and smaller than the actual
		1663	filesize.
		1664
		1665	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1666	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1667
		1668	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1669	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1670	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1671	(which is set to C<MAP_ANON> if your system only provides this
		1672	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1673	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1674	C<IO::AIO::MAP_NONBLOCK>
		1675
		1676	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1677
		1678	C<$offset> is the offset from the start of the file - it generally must be
		1679	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1680
		1681	Example:
		1682
		1683	use Digest::MD5;
		1684	use IO::AIO;
		1685
		1686	open my $fh, "<verybigfile"
		1687	or die "$!";
		1688
		1689	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1690	or die "verybigfile: $!";
		1691
		1692	my $fast_md5 = md5 $data;
		1693
		1694	=item IO::AIO::munmap $scalar
		1695
		1696	Removes a previous mmap and undefines the C<$scalar>.
		1697
		1698	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1699
		1700	Calls the C<munlock> function, undoing the effects of a previous
		1701	C<aio_mlock> call (see its description for details).
		1702
		1703	=item IO::AIO::munlockall
		1704
		1705	Calls the C<munlockall> function.
		1706
		1707	On systems that do not implement C<munlockall>, this function returns
		1708	ENOSYS, otherwise the return value of C<munlockall>.
		1709
		1710	=back
		1711
1251	=cut	1712	=cut
1252		1713
1253	# support function to convert a fd into a perl filehandle
1254	sub _fd2fh {
1255	return undef if $_[0] < 0;
1256
1257	# try to generate nice filehandles
1258	my $sym = "IO::AIO::fd#$_[0]";
1259	local *$sym;
1260
1261	open *$sym, "+<&=$_[0]" # usually works under any unix
1262	or open *$sym, "<&=$_[0]" # cygwin needs this
1263	or open *$sym, ">&=$_[0]" # or this
1264	or return undef;
1265
1266	*$sym
1267	}
1268
1269	min_parallel 8;	1714	min_parallel 8;
1270		1715
1271	END { flush }	1716	END { flush }
1272		1717
1273	1;	1718	1;
		1719
		1720	=head1 EVENT LOOP INTEGRATION
		1721
		1722	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1723	automatically into many event loops:
		1724
		1725	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1726	use AnyEvent::AIO;
		1727
		1728	You can also integrate IO::AIO manually into many event loops, here are
		1729	some examples of how to do this:
		1730
		1731	# EV integration
		1732	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1733
		1734	# Event integration
		1735	Event->io (fd => IO::AIO::poll_fileno,
		1736	poll => 'r',
		1737	cb => \&IO::AIO::poll_cb);
		1738
		1739	# Glib/Gtk2 integration
		1740	add_watch Glib::IO IO::AIO::poll_fileno,
		1741	in => sub { IO::AIO::poll_cb; 1 };
		1742
		1743	# Tk integration
		1744	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1745	readable => \&IO::AIO::poll_cb);
		1746
		1747	# Danga::Socket integration
		1748	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1749	\&IO::AIO::poll_cb);
1274		1750
1275	=head2 FORK BEHAVIOUR	1751	=head2 FORK BEHAVIOUR
1276		1752
1277	This module should do "the right thing" when the process using it forks:	1753	This module should do "the right thing" when the process using it forks:
1278		1754
…		…
1311		1787
1312	Known bugs will be fixed in the next release.	1788	Known bugs will be fixed in the next release.
1313		1789
1314	=head1 SEE ALSO	1790	=head1 SEE ALSO
1315		1791
1316	L<Coro::AIO>.	1792	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1793	more natural syntax.
1317		1794
1318	=head1 AUTHOR	1795	=head1 AUTHOR
1319		1796
1320	Marc Lehmann <schmorp@schmorp.de>	1797	Marc Lehmann <schmorp@schmorp.de>
1321	http://home.schmorp.de/	1798	http://home.schmorp.de/

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