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Revision 1.108 by root, Fri Jun 1 13:25:50 2007 UTC vs.
Revision 1.205 by root, Mon Jul 18 03:09:06 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 = '4.0';
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_realpath aio_sync aio_fsync
		178	aio_fdatasync aio_sync_file_range aio_fallocate
		179	aio_pathsync aio_readahead
		180	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	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
200	aio_chown aio_chmod aio_utime);	182	aio_chmod aio_utime aio_truncate
		183	aio_msync aio_mtouch aio_mlock aio_mlockall
		184	aio_statvfs);
		185
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	188	min_parallel max_parallel max_idle idle_timeout
204	nreqs nready npending nthreads	189	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	190	max_poll_time max_poll_reqs
		191	sendfile fadvise madvise
		192	mmap munmap munlock munlockall);
		193
		194	push @AIO_REQ, qw(aio_busy); # not exported
206		195
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	196	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		197
209	require XSLoader;	198	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	199	XSLoader::load ("IO::AIO", $VERSION);
211	}	200	}
212		201
213	=head1 FUNCTIONS	202	=head1 FUNCTIONS
		203
		204	=head2 QUICK OVERVIEW
		205
		206	This section simply lists the prototypes of the most important functions
		207	for quick reference. See the following sections for function-by-function
		208	documentation.
		209
		210	aio_open $pathname, $flags, $mode, $callback->($fh)
		211	aio_close $fh, $callback->($status)
		212	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		214	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		215	aio_readahead $fh,$offset,$length, $callback->($retval)
		216	aio_stat $fh_or_path, $callback->($status)
		217	aio_lstat $fh, $callback->($status)
		218	aio_statvfs $fh_or_path, $callback->($statvfs)
		219	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		220	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		221	aio_truncate $fh_or_path, $offset, $callback->($status)
		222	aio_chmod $fh_or_path, $mode, $callback->($status)
		223	aio_unlink $pathname, $callback->($status)
		224	aio_mknod $path, $mode, $dev, $callback->($status)
		225	aio_link $srcpath, $dstpath, $callback->($status)
		226	aio_symlink $srcpath, $dstpath, $callback->($status)
		227	aio_readlink $path, $callback->($link)
		228	aio_realpath $path, $callback->($link)
		229	aio_rename $srcpath, $dstpath, $callback->($status)
		230	aio_mkdir $pathname, $mode, $callback->($status)
		231	aio_rmdir $pathname, $callback->($status)
		232	aio_readdir $pathname, $callback->($entries)
		233	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		234	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		235	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		236	aio_load $path, $data, $callback->($status)
		237	aio_copy $srcpath, $dstpath, $callback->($status)
		238	aio_move $srcpath, $dstpath, $callback->($status)
		239	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		240	aio_rmtree $path, $callback->($status)
		241	aio_sync $callback->($status)
		242	aio_fsync $fh, $callback->($status)
		243	aio_fdatasync $fh, $callback->($status)
		244	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		245	aio_pathsync $path, $callback->($status)
		246	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		247	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		248	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		249	aio_mlockall $flags, $callback->($status)
		250	aio_group $callback->(...)
		251	aio_nop $callback->()
		252
		253	$prev_pri = aioreq_pri [$pri]
		254	aioreq_nice $pri_adjust
		255
		256	IO::AIO::poll_wait
		257	IO::AIO::poll_cb
		258	IO::AIO::poll
		259	IO::AIO::flush
		260	IO::AIO::max_poll_reqs $nreqs
		261	IO::AIO::max_poll_time $seconds
		262	IO::AIO::min_parallel $nthreads
		263	IO::AIO::max_parallel $nthreads
		264	IO::AIO::max_idle $nthreads
		265	IO::AIO::idle_timeout $seconds
		266	IO::AIO::max_outstanding $maxreqs
		267	IO::AIO::nreqs
		268	IO::AIO::nready
		269	IO::AIO::npending
		270
		271	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		272	IO::AIO::fadvise $fh, $offset, $len, $advice
		273	IO::AIO::madvise $scalar, $offset, $length, $advice
		274	IO::AIO::mprotect $scalar, $offset, $length, $protect
		275	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		276	IO::AIO::munlockall
214		277
215	=head2 AIO REQUEST FUNCTIONS	278	=head2 AIO REQUEST FUNCTIONS
216		279
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	280	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	281	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	282	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	283	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	284	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	285	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	286	syscall has been executed asynchronously.
224		287
225	All functions expecting a filehandle keep a copy of the filehandle	288	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	289	internally until the request has finished.
227		290
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	304	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)	305	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	306	use something else to ensure your scalar has the correct contents.
244		307
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	308	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	309	handles correctly whether it is set or not.
247		310
248	=over 4	311	=over 4
249		312
250	=item $prev_pri = aioreq_pri [$pri]	313	=item $prev_pri = aioreq_pri [$pri]
251		314
…		…
298	by the umask in effect then the request is being executed, so better never	361	by the umask in effect then the request is being executed, so better never
299	change the umask.	362	change the umask.
300		363
301	Example:	364	Example:
302		365
303	aio_open "/etc/passwd", O_RDONLY, 0, sub {	366	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
304	if ($_[0]) {	367	if ($_[0]) {
305	print "open successful, fh is $_[0]\n";	368	print "open successful, fh is $_[0]\n";
306	...	369	...
307	} else {	370	} else {
308	die "open failed: $!\n";	371	die "open failed: $!\n";
309	}	372	}
310	};	373	};
311		374
		375	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		376	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		377	following POSIX and non-POSIX constants are available (missing ones on
		378	your system are, as usual, C<0>):
		379
		380	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		381	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		382	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		383
312		384
313	=item aio_close $fh, $callback->($status)	385	=item aio_close $fh, $callback->($status)
314		386
315	Asynchronously close a file and call the callback with the result	387	Asynchronously close a file and call the callback with the result
316	code. I<WARNING:> although accepted, you should not pass in a perl	388	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		389
321	This is supposed to be a bug in the API, so that might change. It's	390	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
322	therefore best to avoid this function.	391	closing the file descriptor associated with the filehandle itself.
323		392
		393	Therefore, C<aio_close> will not close the filehandle - instead it will
		394	use dup2 to overwrite the file descriptor with the write-end of a pipe
		395	(the pipe fd will be created on demand and will be cached).
		396
		397	Or in other words: the file descriptor will be closed, but it will not be
		398	free for reuse until the perl filehandle is closed.
		399
		400	=cut
324		401
325	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	402	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
326		403
327	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	404	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
328		405
329	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	406	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	407	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
331	callback without the actual number of bytes read (or -1 on error, just	408	and calls the callback without the actual number of bytes read (or -1 on
		409	error, just like the syscall).
		410
		411	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		412	offset plus the actual number of bytes read.
		413
332	like the syscall). If C<offset> is undefined, then the current file offset	414	If C<$offset> is undefined, then the current file descriptor offset will
333	will be used (and updated), otherwise the file offset will not be changed	415	be used (and updated), otherwise the file descriptor offset will not be
334	by these calls.	416	changed by these calls.
		417
		418	If C<$length> is undefined in C<aio_write>, use the remaining length of
		419	C<$data>.
		420
		421	If C<$dataoffset> is less than zero, it will be counted from the end of
		422	C<$data>.
335		423
336	The C<$data> scalar I<MUST NOT> be modified in any way while the request	424	The C<$data> scalar I<MUST NOT> be modified in any way while the request
337	is outstanding. Modifying it can result in segfaults or World War III (if	425	is outstanding. Modifying it can result in segfaults or World War III (if
338	the necessary/optional hardware is installed).	426	the necessary/optional hardware is installed).
339		427
…		…
350		438
351	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	439	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
352	reading at byte offset C<$in_offset>, and starts writing at the current	440	reading at byte offset C<$in_offset>, and starts writing at the current
353	file offset of C<$out_fh>. Because of that, it is not safe to issue more	441	file offset of C<$out_fh>. Because of that, it is not safe to issue more
354	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	442	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
355	other.	443	other. The same C<$in_fh> works fine though, as this function does not
		444	move or use the file offset of C<$in_fh>.
356		445
		446	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		447	are written, and there is no way to find out how many more bytes have been
		448	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		449	number of bytes written to C<$out_fh>. Only if the result value equals
		450	C<$length> one can assume that C<$length> bytes have been read.
		451
		452	Unlike with other C<aio_> functions, it makes a lot of sense to use
		453	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		454	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		455	the socket I/O will be non-blocking. Note, however, that you can run
		456	into a trap where C<aio_sendfile> reads some data with readahead, then
		457	fails to write all data, and when the socket is ready the next time, the
		458	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		459	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		460	resource usage.
		461
357	This call tries to make use of a native C<sendfile> syscall to provide	462	This call tries to make use of a native C<sendfile>-like syscall to
358	zero-copy operation. For this to work, C<$out_fh> should refer to a	463	provide zero-copy operation. For this to work, C<$out_fh> should refer to
359	socket, and C<$in_fh> should refer to mmap'able file.	464	a socket, and C<$in_fh> should refer to an mmap'able file.
360		465
361	If the native sendfile call fails or is not implemented, it will be	466	If a native sendfile cannot be found or it fails with C<ENOSYS>,
362	emulated, so you can call C<aio_sendfile> on any type of filehandle	467	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		468	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
363	regardless of the limitations of the operating system.	469	type of filehandle regardless of the limitations of the operating system.
364		470
365	Please note, however, that C<aio_sendfile> can read more bytes from	471	As native sendfile syscalls (as practically any non-POSIX interface hacked
366	C<$in_fh> than are written, and there is no way to find out how many	472	together in a hurry to improve benchmark numbers) tend to be rather buggy
367	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	473	on many systems, this implementation tries to work around some known bugs
368	provides the number of bytes written to C<$out_fh>. Only if the result	474	in Linux and FreeBSD kernels (probably others, too), but that might fail,
369	value equals C<$length> one can assume that C<$length> bytes have been	475	so you really really should check the return value of C<aio_sendfile> -
370	read.	476	fewre bytes than expected might have been transferred.
371		477
372		478
373	=item aio_readahead $fh,$offset,$length, $callback->($retval)	479	=item aio_readahead $fh,$offset,$length, $callback->($retval)
374		480
375	C<aio_readahead> populates the page cache with data from a file so that	481	C<aio_readahead> populates the page cache with data from a file so that
…		…
398		504
399	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	505	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
400	error when stat'ing a large file, the results will be silently truncated	506	error when stat'ing a large file, the results will be silently truncated
401	unless perl itself is compiled with large file support.	507	unless perl itself is compiled with large file support.
402		508
		509	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		510	following constants and functions (if not implemented, the constants will
		511	be C<0> and the functions will either C<croak> or fall back on traditional
		512	behaviour).
		513
		514	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		515	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		516	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		517
403	Example: Print the length of F</etc/passwd>:	518	Example: Print the length of F</etc/passwd>:
404		519
405	aio_stat "/etc/passwd", sub {	520	aio_stat "/etc/passwd", sub {
406	$_[0] and die "stat failed: $!";	521	$_[0] and die "stat failed: $!";
407	print "size is ", -s _, "\n";	522	print "size is ", -s _, "\n";
408	};	523	};
409		524
410		525
		526	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		527
		528	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		529	whether a file handle or path was passed.
		530
		531	On success, the callback is passed a hash reference with the following
		532	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		533	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		534	is passed.
		535
		536	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		537	C<ST_NOSUID>.
		538
		539	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		540	their correct value when available, or to C<0> on systems that do
		541	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		542	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		543	C<ST_NODIRATIME> and C<ST_RELATIME>.
		544
		545	Example: stat C</wd> and dump out the data if successful.
		546
		547	aio_statvfs "/wd", sub {
		548	my $f = $_[0]
		549	or die "statvfs: $!";
		550
		551	use Data::Dumper;
		552	say Dumper $f;
		553	};
		554
		555	# result:
		556	{
		557	bsize => 1024,
		558	bfree => 4333064312,
		559	blocks => 10253828096,
		560	files => 2050765568,
		561	flag => 4096,
		562	favail => 2042092649,
		563	bavail => 4333064312,
		564	ffree => 2042092649,
		565	namemax => 255,
		566	frsize => 1024,
		567	fsid => 1810
		568	}
		569
		570
411	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	571	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
412		572
413	Works like perl's C<utime> function (including the special case of $atime	573	Works like perl's C<utime> function (including the special case of $atime
414	and $mtime being undef). Fractional times are supported if the underlying	574	and $mtime being undef). Fractional times are supported if the underlying
415	syscalls support them.	575	syscalls support them.
…		…
437	aio_chown "path", 0, -1;	597	aio_chown "path", 0, -1;
438	# same as above:	598	# same as above:
439	aio_chown "path", 0, undef;	599	aio_chown "path", 0, undef;
440		600
441		601
		602	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		603
		604	Works like truncate(2) or ftruncate(2).
		605
		606
442	=item aio_chmod $fh_or_path, $mode, $callback->($status)	607	=item aio_chmod $fh_or_path, $mode, $callback->($status)
443		608
444	Works like perl's C<chmod> function.	609	Works like perl's C<chmod> function.
445		610
446		611
…		…
458		623
459	The only (POSIX-) portable way of calling this function is:	624	The only (POSIX-) portable way of calling this function is:
460		625
461	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	626	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
462		627
		628	See C<aio_stat> for info about some potentially helpful extra constants
		629	and functions.
463		630
464	=item aio_link $srcpath, $dstpath, $callback->($status)	631	=item aio_link $srcpath, $dstpath, $callback->($status)
465		632
466	Asynchronously create a new link to the existing object at C<$srcpath> at	633	Asynchronously create a new link to the existing object at C<$srcpath> at
467	the path C<$dstpath> and call the callback with the result code.	634	the path C<$dstpath> and call the callback with the result code.
…		…
478	Asynchronously read the symlink specified by C<$path> and pass it to	645	Asynchronously read the symlink specified by C<$path> and pass it to
479	the callback. If an error occurs, nothing or undef gets passed to the	646	the callback. If an error occurs, nothing or undef gets passed to the
480	callback.	647	callback.
481		648
482		649
		650	=item aio_realpath $path, $callback->($path)
		651
		652	Asynchronously make the path absolute and resolve any symlinks in
		653	C<$path>. The resulting path only consists of directories (Same as
		654	L<Cwd::realpath>).
		655
		656	This request can be used to get the absolute path of the current working
		657	directory by passing it a path of F<.> (a single dot).
		658
		659
483	=item aio_rename $srcpath, $dstpath, $callback->($status)	660	=item aio_rename $srcpath, $dstpath, $callback->($status)
484		661
485	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	662	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
486	rename(2) and call the callback with the result code.	663	rename(2) and call the callback with the result code.
487		664
…		…
503		680
504	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	681	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
505	directory (i.e. opendir + readdir + closedir). The entries will not be	682	directory (i.e. opendir + readdir + closedir). The entries will not be
506	sorted, and will B<NOT> include the C<.> and C<..> entries.	683	sorted, and will B<NOT> include the C<.> and C<..> entries.
507		684
508	The callback a single argument which is either C<undef> or an array-ref	685	The callback is passed a single argument which is either C<undef> or an
509	with the filenames.	686	array-ref with the filenames.
		687
		688
		689	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		690
		691	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		692	behaviour and output format. In case of an error, C<$entries> will be
		693	C<undef>.
		694
		695	The flags are a combination of the following constants, ORed together (the
		696	flags will also be passed to the callback, possibly modified):
		697
		698	=over 4
		699
		700	=item IO::AIO::READDIR_DENTS
		701
		702	When this flag is off, then the callback gets an arrayref consisting of
		703	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		704	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		705	entry in more detail.
		706
		707	C<$name> is the name of the entry.
		708
		709	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		710
		711	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		712	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		713	C<IO::AIO::DT_WHT>.
		714
		715	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		716	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		717	scalars are read-only: you can not modify them.
		718
		719	C<$inode> is the inode number (which might not be exact on systems with 64
		720	bit inode numbers and 32 bit perls). This field has unspecified content on
		721	systems that do not deliver the inode information.
		722
		723	=item IO::AIO::READDIR_DIRS_FIRST
		724
		725	When this flag is set, then the names will be returned in an order where
		726	likely directories come first, in optimal stat order. This is useful when
		727	you need to quickly find directories, or you want to find all directories
		728	while avoiding to stat() each entry.
		729
		730	If the system returns type information in readdir, then this is used
		731	to find directories directly. Otherwise, likely directories are names
		732	beginning with ".", or otherwise names with no dots, of which names with
		733	short names are tried first.
		734
		735	=item IO::AIO::READDIR_STAT_ORDER
		736
		737	When this flag is set, then the names will be returned in an order
		738	suitable for stat()'ing each one. That is, when you plan to stat()
		739	all files in the given directory, then the returned order will likely
		740	be fastest.
		741
		742	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		743	the likely dirs come first, resulting in a less optimal stat order.
		744
		745	=item IO::AIO::READDIR_FOUND_UNKNOWN
		746
		747	This flag should not be set when calling C<aio_readdirx>. Instead, it
		748	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		749	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		750	C<$type>'s are known, which can be used to speed up some algorithms.
		751
		752	=back
510		753
511		754
512	=item aio_load $path, $data, $callback->($status)	755	=item aio_load $path, $data, $callback->($status)
513		756
514	This is a composite request that tries to fully load the given file into	757	This is a composite request that tries to fully load the given file into
515	memory. Status is the same as with aio_read.	758	memory. Status is the same as with aio_read.
516		759
517	=cut	760	=cut
518		761
519	sub aio_load($$;$) {	762	sub aio_load($$;$) {
520	aio_block {
521	my ($path, undef, $cb) = @_;	763	my ($path, undef, $cb) = @_;
522	my $data = \$_[1];	764	my $data = \$_[1];
523		765
524	my $pri = aioreq_pri;	766	my $pri = aioreq_pri;
525	my $grp = aio_group $cb;	767	my $grp = aio_group $cb;
		768
		769	aioreq_pri $pri;
		770	add $grp aio_open $path, O_RDONLY, 0, sub {
		771	my $fh = shift
		772	or return $grp->result (-1);
526		773
527	aioreq_pri $pri;	774	aioreq_pri $pri;
528	add $grp aio_open $path, O_RDONLY, 0, sub {
529	my $fh = shift
530	or return $grp->result (-1);
531
532	aioreq_pri $pri;
533	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	775	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
534	$grp->result ($_[0]);	776	$grp->result ($_[0]);
535	};
536	};	777	};
537
538	$grp
539	}	778	};
		779
		780	$grp
540	}	781	}
541		782
542	=item aio_copy $srcpath, $dstpath, $callback->($status)	783	=item aio_copy $srcpath, $dstpath, $callback->($status)
543		784
544	Try to copy the I<file> (directories not supported as either source or	785	Try to copy the I<file> (directories not supported as either source or
545	destination) from C<$srcpath> to C<$dstpath> and call the callback with	786	destination) from C<$srcpath> to C<$dstpath> and call the callback with
546	the C<0> (error) or C<-1> ok.	787	a status of C<0> (ok) or C<-1> (error, see C<$!>).
547		788
548	This is a composite request that it creates the destination file with	789	This is a composite request that creates the destination file with
549	mode 0200 and copies the contents of the source file into it using	790	mode 0200 and copies the contents of the source file into it using
550	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	791	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
551	uid/gid, in that order.	792	uid/gid, in that order.
552		793
553	If an error occurs, the partial destination file will be unlinked, if	794	If an error occurs, the partial destination file will be unlinked, if
…		…
555	errors are being ignored.	796	errors are being ignored.
556		797
557	=cut	798	=cut
558		799
559	sub aio_copy($$;$) {	800	sub aio_copy($$;$) {
560	aio_block {
561	my ($src, $dst, $cb) = @_;	801	my ($src, $dst, $cb) = @_;
562		802
563	my $pri = aioreq_pri;	803	my $pri = aioreq_pri;
564	my $grp = aio_group $cb;	804	my $grp = aio_group $cb;
565		805
566	aioreq_pri $pri;	806	aioreq_pri $pri;
567	add $grp aio_open $src, O_RDONLY, 0, sub {	807	add $grp aio_open $src, O_RDONLY, 0, sub {
568	if (my $src_fh = $_[0]) {	808	if (my $src_fh = $_[0]) {
569	my @stat = stat $src_fh;	809	my @stat = stat $src_fh; # hmm, might block over nfs?
570		810
571	aioreq_pri $pri;	811	aioreq_pri $pri;
572	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	812	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
573	if (my $dst_fh = $_[0]) {	813	if (my $dst_fh = $_[0]) {
574	aioreq_pri $pri;	814	aioreq_pri $pri;
575	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	815	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
576	if ($_[0] == $stat[7]) {	816	if ($_[0] == $stat[7]) {
577	$grp->result (0);	817	$grp->result (0);
578	close $src_fh;	818	close $src_fh;
579		819
580	# those should not normally block. should. should.
581	utime $stat[8], $stat[9], $dst;
582	chmod $stat[2] & 07777, $dst_fh;
583	chown $stat[4], $stat[5], $dst_fh;
584	close $dst_fh;
585	} else {	820	my $ch = sub {
586	$grp->result (-1);
587	close $src_fh;
588	close $dst_fh;
589
590	aioreq $pri;	821	aioreq_pri $pri;
		822	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		823	aioreq_pri $pri;
		824	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		825	aioreq_pri $pri;
591	add $grp aio_unlink $dst;	826	add $grp aio_close $dst_fh;
		827	}
		828	};
592	}	829	};
		830
		831	aioreq_pri $pri;
		832	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		833	if ($_[0] < 0 && $! == ENOSYS) {
		834	aioreq_pri $pri;
		835	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		836	} else {
		837	$ch->();
		838	}
		839	};
		840	} else {
		841	$grp->result (-1);
		842	close $src_fh;
		843	close $dst_fh;
		844
		845	aioreq $pri;
		846	add $grp aio_unlink $dst;
593	};	847	}
594	} else {
595	$grp->result (-1);
596	}	848	};
		849	} else {
		850	$grp->result (-1);
597	},	851	}
598
599	} else {
600	$grp->result (-1);
601	}	852	},
		853
		854	} else {
		855	$grp->result (-1);
602	};	856	}
603
604	$grp
605	}	857	};
		858
		859	$grp
606	}	860	}
607		861
608	=item aio_move $srcpath, $dstpath, $callback->($status)	862	=item aio_move $srcpath, $dstpath, $callback->($status)
609		863
610	Try to move the I<file> (directories not supported as either source or	864	Try to move the I<file> (directories not supported as either source or
611	destination) from C<$srcpath> to C<$dstpath> and call the callback with	865	destination) from C<$srcpath> to C<$dstpath> and call the callback with
612	the C<0> (error) or C<-1> ok.	866	a status of C<0> (ok) or C<-1> (error, see C<$!>).
613		867
614	This is a composite request that tries to rename(2) the file first. If	868	This is a composite request that tries to rename(2) the file first; if
615	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	869	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
616	that is successful, unlinking the C<$srcpath>.	870	that is successful, unlinks the C<$srcpath>.
617		871
618	=cut	872	=cut
619		873
620	sub aio_move($$;$) {	874	sub aio_move($$;$) {
621	aio_block {
622	my ($src, $dst, $cb) = @_;	875	my ($src, $dst, $cb) = @_;
623		876
624	my $pri = aioreq_pri;	877	my $pri = aioreq_pri;
625	my $grp = aio_group $cb;	878	my $grp = aio_group $cb;
626		879
627	aioreq_pri $pri;	880	aioreq_pri $pri;
628	add $grp aio_rename $src, $dst, sub {	881	add $grp aio_rename $src, $dst, sub {
629	if ($_[0] && $! == EXDEV) {	882	if ($_[0] && $! == EXDEV) {
630	aioreq_pri $pri;	883	aioreq_pri $pri;
631	add $grp aio_copy $src, $dst, sub {	884	add $grp aio_copy $src, $dst, sub {
632	$grp->result ($_[0]);
633
634	if (!$_[0]) {
635	aioreq_pri $pri;
636	add $grp aio_unlink $src;
637	}
638	};
639	} else {
640	$grp->result ($_[0]);	885	$grp->result ($_[0]);
		886
		887	unless ($_[0]) {
		888	aioreq_pri $pri;
		889	add $grp aio_unlink $src;
		890	}
641	}	891	};
		892	} else {
		893	$grp->result ($_[0]);
642	};	894	}
643
644	$grp
645	}	895	};
		896
		897	$grp
646	}	898	}
647		899
648	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	900	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
649		901
650	Scans a directory (similar to C<aio_readdir>) but additionally tries to	902	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
670		922
671	Implementation notes.	923	Implementation notes.
672		924
673	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	925	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
674		926
		927	If readdir returns file type information, then this is used directly to
		928	find directories.
		929
675	After reading the directory, the modification time, size etc. of the	930	Otherwise, after reading the directory, the modification time, size etc.
676	directory before and after the readdir is checked, and if they match (and	931	of the directory before and after the readdir is checked, and if they
677	isn't the current time), the link count will be used to decide how many	932	match (and isn't the current time), the link count will be used to decide
678	entries are directories (if >= 2). Otherwise, no knowledge of the number	933	how many entries are directories (if >= 2). Otherwise, no knowledge of the
679	of subdirectories will be assumed.	934	number of subdirectories will be assumed.
680		935
681	Then entries will be sorted into likely directories (everything without	936	Then entries will be sorted into likely directories a non-initial dot
682	a non-initial dot currently) and likely non-directories (everything	937	currently) and likely non-directories (see C<aio_readdirx>). Then every
683	else). Then every entry plus an appended C</.> will be C<stat>'ed,	938	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
684	likely directories first. If that succeeds, it assumes that the entry	939	in order of their inode numbers. If that succeeds, it assumes that the
685	is a directory or a symlink to directory (which will be checked	940	entry is a directory or a symlink to directory (which will be checked
686	seperately). This is often faster than stat'ing the entry itself because	941	seperately). This is often faster than stat'ing the entry itself because
687	filesystems might detect the type of the entry without reading the inode	942	filesystems might detect the type of the entry without reading the inode
688	data (e.g. ext2fs filetype feature).	943	data (e.g. ext2fs filetype feature), even on systems that cannot return
		944	the filetype information on readdir.
689		945
690	If the known number of directories (link count - 2) has been reached, the	946	If the known number of directories (link count - 2) has been reached, the
691	rest of the entries is assumed to be non-directories.	947	rest of the entries is assumed to be non-directories.
692		948
693	This only works with certainty on POSIX (= UNIX) filesystems, which	949	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
698	directory counting heuristic.	954	directory counting heuristic.
699		955
700	=cut	956	=cut
701		957
702	sub aio_scandir($$;$) {	958	sub aio_scandir($$;$) {
703	aio_block {
704	my ($path, $maxreq, $cb) = @_;	959	my ($path, $maxreq, $cb) = @_;
705		960
706	my $pri = aioreq_pri;	961	my $pri = aioreq_pri;
707		962
708	my $grp = aio_group $cb;	963	my $grp = aio_group $cb;
709		964
710	$maxreq = 4 if $maxreq <= 0;	965	$maxreq = 4 if $maxreq <= 0;
711		966
712	# stat once	967	# stat once
		968	aioreq_pri $pri;
		969	add $grp aio_stat $path, sub {
		970	return $grp->result () if $_[0];
		971	my $now = time;
		972	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		973
		974	# read the directory entries
713	aioreq_pri $pri;	975	aioreq_pri $pri;
714	add $grp aio_stat $path, sub {	976	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		977	my $entries = shift
715	return $grp->result () if $_[0];	978	or return $grp->result ();
716	my $now = time;
717	my $hash1 = join ":", (stat _)[0,1,3,7,9];
718		979
719	# read the directory entries	980	# stat the dir another time
720	aioreq_pri $pri;	981	aioreq_pri $pri;
721	add $grp aio_readdir $path, sub {
722	my $entries = shift
723	or return $grp->result ();
724
725	# stat the dir another time
726	aioreq_pri $pri;
727	add $grp aio_stat $path, sub {	982	add $grp aio_stat $path, sub {
728	my $hash2 = join ":", (stat _)[0,1,3,7,9];	983	my $hash2 = join ":", (stat _)[0,1,3,7,9];
729		984
730	my $ndirs;	985	my $ndirs;
731		986
732	# take the slow route if anything looks fishy	987	# take the slow route if anything looks fishy
733	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	988	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
734	$ndirs = -1;	989	$ndirs = -1;
735	} else {	990	} else {
736	# if nlink == 2, we are finished	991	# if nlink == 2, we are finished
737	# on non-posix-fs's, we rely on nlink < 2	992	# for non-posix-fs's, we rely on nlink < 2
738	$ndirs = (stat _)[3] - 2	993	$ndirs = (stat _)[3] - 2
739	or return $grp->result ([], $entries);	994	or return $grp->result ([], $entries);
740	}	995	}
741		996
742	# sort into likely dirs and likely nondirs
743	# dirs == files without ".", short entries first
744	$entries = [map $_->[0],
745	sort { $b->[1] cmp $a->[1] }
746	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
747	@$entries];
748
749	my (@dirs, @nondirs);	997	my (@dirs, @nondirs);
750		998
751	my $statgrp = add $grp aio_group sub {	999	my $statgrp = add $grp aio_group sub {
752	$grp->result (\@dirs, \@nondirs);	1000	$grp->result (\@dirs, \@nondirs);
753	};	1001	};
754		1002
755	limit $statgrp $maxreq;	1003	limit $statgrp $maxreq;
756	feed $statgrp sub {	1004	feed $statgrp sub {
757	return unless @$entries;	1005	return unless @$entries;
758	my $entry = pop @$entries;	1006	my $entry = shift @$entries;
759		1007
760	aioreq_pri $pri;	1008	aioreq_pri $pri;
761	add $statgrp aio_stat "$path/$entry/.", sub {	1009	add $statgrp aio_stat "$path/$entry/.", sub {
762	if ($_[0] < 0) {	1010	if ($_[0] < 0) {
763	push @nondirs, $entry;	1011	push @nondirs, $entry;
764	} else {	1012	} else {
765	# need to check for real directory	1013	# need to check for real directory
766	aioreq_pri $pri;	1014	aioreq_pri $pri;
767	add $statgrp aio_lstat "$path/$entry", sub {	1015	add $statgrp aio_lstat "$path/$entry", sub {
768	if (-d _) {	1016	if (-d _) {
769	push @dirs, $entry;	1017	push @dirs, $entry;
770		1018
771	unless (--$ndirs) {	1019	unless (--$ndirs) {
772	push @nondirs, @$entries;	1020	push @nondirs, @$entries;
773	feed $statgrp;	1021	feed $statgrp;
774	}
775	} else {
776	push @nondirs, $entry;
777	}	1022	}
		1023	} else {
		1024	push @nondirs, $entry;
778	}	1025	}
779	}	1026	}
780	};	1027	}
781	};	1028	};
782	};	1029	};
783	};	1030	};
784	};	1031	};
785
786	$grp
787	}	1032	};
		1033
		1034	$grp
788	}	1035	}
789		1036
790	=item aio_rmtree $path, $callback->($status)	1037	=item aio_rmtree $path, $callback->($status)
791		1038
792	Delete a directory tree starting (and including) C<$path>, return the	1039	Delete a directory tree starting (and including) C<$path>, return the
…		…
796		1043
797	=cut	1044	=cut
798		1045
799	sub aio_rmtree;	1046	sub aio_rmtree;
800	sub aio_rmtree($;$) {	1047	sub aio_rmtree($;$) {
801	aio_block {
802	my ($path, $cb) = @_;	1048	my ($path, $cb) = @_;
803		1049
804	my $pri = aioreq_pri;	1050	my $pri = aioreq_pri;
805	my $grp = aio_group $cb;	1051	my $grp = aio_group $cb;
806		1052
807	aioreq_pri $pri;	1053	aioreq_pri $pri;
808	add $grp aio_scandir $path, 0, sub {	1054	add $grp aio_scandir $path, 0, sub {
809	my ($dirs, $nondirs) = @_;	1055	my ($dirs, $nondirs) = @_;
810		1056
811	my $dirgrp = aio_group sub {	1057	my $dirgrp = aio_group sub {
812	add $grp aio_rmdir $path, sub {	1058	add $grp aio_rmdir $path, sub {
813	$grp->result ($_[0]);	1059	$grp->result ($_[0]);
814	};
815	};	1060	};
816
817	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
818	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
819
820	add $grp $dirgrp;
821	};	1061	};
822		1062
823	$grp	1063	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1064	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1065
		1066	add $grp $dirgrp;
824	}	1067	};
		1068
		1069	$grp
825	}	1070	}
		1071
		1072	=item aio_sync $callback->($status)
		1073
		1074	Asynchronously call sync and call the callback when finished.
826		1075
827	=item aio_fsync $fh, $callback->($status)	1076	=item aio_fsync $fh, $callback->($status)
828		1077
829	Asynchronously call fsync on the given filehandle and call the callback	1078	Asynchronously call fsync on the given filehandle and call the callback
830	with the fsync result code.	1079	with the fsync result code.
…		…
834	Asynchronously call fdatasync on the given filehandle and call the	1083	Asynchronously call fdatasync on the given filehandle and call the
835	callback with the fdatasync result code.	1084	callback with the fdatasync result code.
836		1085
837	If this call isn't available because your OS lacks it or it couldn't be	1086	If this call isn't available because your OS lacks it or it couldn't be
838	detected, it will be emulated by calling C<fsync> instead.	1087	detected, it will be emulated by calling C<fsync> instead.
		1088
		1089	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1090
		1091	Sync the data portion of the file specified by C<$offset> and C<$length>
		1092	to disk (but NOT the metadata), by calling the Linux-specific
		1093	sync_file_range call. If sync_file_range is not available or it returns
		1094	ENOSYS, then fdatasync or fsync is being substituted.
		1095
		1096	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1097	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1098	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1099	manpage for details.
		1100
		1101	=item aio_pathsync $path, $callback->($status)
		1102
		1103	This request tries to open, fsync and close the given path. This is a
		1104	composite request intended to sync directories after directory operations
		1105	(E.g. rename). This might not work on all operating systems or have any
		1106	specific effect, but usually it makes sure that directory changes get
		1107	written to disc. It works for anything that can be opened for read-only,
		1108	not just directories.
		1109
		1110	Future versions of this function might fall back to other methods when
		1111	C<fsync> on the directory fails (such as calling C<sync>).
		1112
		1113	Passes C<0> when everything went ok, and C<-1> on error.
		1114
		1115	=cut
		1116
		1117	sub aio_pathsync($;$) {
		1118	my ($path, $cb) = @_;
		1119
		1120	my $pri = aioreq_pri;
		1121	my $grp = aio_group $cb;
		1122
		1123	aioreq_pri $pri;
		1124	add $grp aio_open $path, O_RDONLY, 0, sub {
		1125	my ($fh) = @_;
		1126	if ($fh) {
		1127	aioreq_pri $pri;
		1128	add $grp aio_fsync $fh, sub {
		1129	$grp->result ($_[0]);
		1130
		1131	aioreq_pri $pri;
		1132	add $grp aio_close $fh;
		1133	};
		1134	} else {
		1135	$grp->result (-1);
		1136	}
		1137	};
		1138
		1139	$grp
		1140	}
		1141
		1142	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1143
		1144	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1145	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1146	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1147	scalar must only be modified in-place while an aio operation is pending on
		1148	it).
		1149
		1150	It calls the C<msync> function of your OS, if available, with the memory
		1151	area starting at C<$offset> in the string and ending C<$length> bytes
		1152	later. If C<$length> is negative, counts from the end, and if C<$length>
		1153	is C<undef>, then it goes till the end of the string. The flags can be
		1154	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1155	C<IO::AIO::MS_SYNC>.
		1156
		1157	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1158
		1159	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1160	scalars.
		1161
		1162	It touches (reads or writes) all memory pages in the specified
		1163	range inside the scalar. All caveats and parameters are the same
		1164	as for C<aio_msync>, above, except for flags, which must be either
		1165	C<0> (which reads all pages and ensures they are instantiated) or
		1166	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1167	writing an octet from it, which dirties the page).
		1168
		1169	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1170
		1171	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1172	scalars.
		1173
		1174	It reads in all the pages of the underlying storage into memory (if any)
		1175	and locks them, so they are not getting swapped/paged out or removed.
		1176
		1177	If C<$length> is undefined, then the scalar will be locked till the end.
		1178
		1179	On systems that do not implement C<mlock>, this function returns C<-1>
		1180	and sets errno to C<ENOSYS>.
		1181
		1182	Note that the corresponding C<munlock> is synchronous and is
		1183	documented under L<MISCELLANEOUS FUNCTIONS>.
		1184
		1185	Example: open a file, mmap and mlock it - both will be undone when
		1186	C<$data> gets destroyed.
		1187
		1188	open my $fh, "<", $path or die "$path: $!";
		1189	my $data;
		1190	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1191	aio_mlock $data; # mlock in background
		1192
		1193	=item aio_mlockall $flags, $callback->($status)
		1194
		1195	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1196	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1197
		1198	On systems that do not implement C<mlockall>, this function returns C<-1>
		1199	and sets errno to C<ENOSYS>.
		1200
		1201	Note that the corresponding C<munlockall> is synchronous and is
		1202	documented under L<MISCELLANEOUS FUNCTIONS>.
		1203
		1204	Example: asynchronously lock all current and future pages into memory.
		1205
		1206	aio_mlockall IO::AIO::MCL_FUTURE;
839		1207
840	=item aio_group $callback->(...)	1208	=item aio_group $callback->(...)
841		1209
842	This is a very special aio request: Instead of doing something, it is a	1210	This is a very special aio request: Instead of doing something, it is a
843	container for other aio requests, which is useful if you want to bundle	1211	container for other aio requests, which is useful if you want to bundle
…		…
893	=item cancel $req	1261	=item cancel $req
894		1262
895	Cancels the request, if possible. Has the effect of skipping execution	1263	Cancels the request, if possible. Has the effect of skipping execution
896	when entering the B<execute> state and skipping calling the callback when	1264	when entering the B<execute> state and skipping calling the callback when
897	entering the the B<result> state, but will leave the request otherwise	1265	entering the the B<result> state, but will leave the request otherwise
898	untouched. That means that requests that currently execute will not be	1266	untouched (with the exception of readdir). That means that requests that
899	stopped and resources held by the request will not be freed prematurely.	1267	currently execute will not be stopped and resources held by the request
		1268	will not be freed prematurely.
900		1269
901	=item cb $req $callback->(...)	1270	=item cb $req $callback->(...)
902		1271
903	Replace (or simply set) the callback registered to the request.	1272	Replace (or simply set) the callback registered to the request.
904		1273
…		…
955	Their lifetime, simplified, looks like this: when they are empty, they	1324	Their lifetime, simplified, looks like this: when they are empty, they
956	will finish very quickly. If they contain only requests that are in the	1325	will finish very quickly. If they contain only requests that are in the
957	C<done> state, they will also finish. Otherwise they will continue to	1326	C<done> state, they will also finish. Otherwise they will continue to
958	exist.	1327	exist.
959		1328
960	That means after creating a group you have some time to add requests. And	1329	That means after creating a group you have some time to add requests
961	in the callbacks of those requests, you can add further requests to the	1330	(precisely before the callback has been invoked, which is only done within
962	group. And only when all those requests have finished will the the group	1331	the C<poll_cb>). And in the callbacks of those requests, you can add
963	itself finish.	1332	further requests to the group. And only when all those requests have
		1333	finished will the the group itself finish.
964		1334
965	=over 4	1335	=over 4
966		1336
967	=item add $grp ...	1337	=item add $grp ...
968		1338
…		…
977	=item $grp->cancel_subs	1347	=item $grp->cancel_subs
978		1348
979	Cancel all subrequests and clears any feeder, but not the group request	1349	Cancel all subrequests and clears any feeder, but not the group request
980	itself. Useful when you queued a lot of events but got a result early.	1350	itself. Useful when you queued a lot of events but got a result early.
981		1351
		1352	The group request will finish normally (you cannot add requests to the
		1353	group).
		1354
982	=item $grp->result (...)	1355	=item $grp->result (...)
983		1356
984	Set the result value(s) that will be passed to the group callback when all	1357	Set the result value(s) that will be passed to the group callback when all
985	subrequests have finished and set thre groups errno to the current value	1358	subrequests have finished and set the groups errno to the current value
986	of errno (just like calling C<errno> without an error number). By default,	1359	of errno (just like calling C<errno> without an error number). By default,
987	no argument will be passed and errno is zero.	1360	no argument will be passed and errno is zero.
988		1361
989	=item $grp->errno ([$errno])	1362	=item $grp->errno ([$errno])
990		1363
…		…
1001	=item feed $grp $callback->($grp)	1374	=item feed $grp $callback->($grp)
1002		1375
1003	Sets a feeder/generator on this group: every group can have an attached	1376	Sets a feeder/generator on this group: every group can have an attached
1004	generator that generates requests if idle. The idea behind this is that,	1377	generator that generates requests if idle. The idea behind this is that,
1005	although you could just queue as many requests as you want in a group,	1378	although you could just queue as many requests as you want in a group,
1006	this might starve other requests for a potentially long time. For	1379	this might starve other requests for a potentially long time. For example,
1007	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1380	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1008	requests, delaying any later requests for a long time.	1381	delaying any later requests for a long time.
1009		1382
1010	To avoid this, and allow incremental generation of requests, you can	1383	To avoid this, and allow incremental generation of requests, you can
1011	instead a group and set a feeder on it that generates those requests. The	1384	instead a group and set a feeder on it that generates those requests. The
1012	feed callback will be called whenever there are few enough (see C<limit>,	1385	feed callback will be called whenever there are few enough (see C<limit>,
1013	below) requests active in the group itself and is expected to queue more	1386	below) requests active in the group itself and is expected to queue more
…		…
1017	not impose any limits).	1390	not impose any limits).
1018		1391
1019	If the feed does not queue more requests when called, it will be	1392	If the feed does not queue more requests when called, it will be
1020	automatically removed from the group.	1393	automatically removed from the group.
1021		1394
1022	If the feed limit is C<0>, it will be set to C<2> automatically.	1395	If the feed limit is C<0> when this method is called, it will be set to
		1396	C<2> automatically.
1023		1397
1024	Example:	1398	Example:
1025		1399
1026	# stat all files in @files, but only ever use four aio requests concurrently:	1400	# stat all files in @files, but only ever use four aio requests concurrently:
1027		1401
…		…
1039	Sets the feeder limit for the group: The feeder will be called whenever	1413	Sets the feeder limit for the group: The feeder will be called whenever
1040	the group contains less than this many requests.	1414	the group contains less than this many requests.
1041		1415
1042	Setting the limit to C<0> will pause the feeding process.	1416	Setting the limit to C<0> will pause the feeding process.
1043		1417
		1418	The default value for the limit is C<0>, but note that setting a feeder
		1419	automatically bumps it up to C<2>.
		1420
1044	=back	1421	=back
1045		1422
1046	=head2 SUPPORT FUNCTIONS	1423	=head2 SUPPORT FUNCTIONS
1047		1424
1048	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1425	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1050	=over 4	1427	=over 4
1051		1428
1052	=item $fileno = IO::AIO::poll_fileno	1429	=item $fileno = IO::AIO::poll_fileno
1053		1430
1054	Return the I<request result pipe file descriptor>. This filehandle must be	1431	Return the I<request result pipe file descriptor>. This filehandle must be
1055	polled for reading by some mechanism outside this module (e.g. Event or	1432	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1056	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1433	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1057	to call C<poll_cb> to check the results.	1434	you have to call C<poll_cb> to check the results.
1058		1435
1059	See C<poll_cb> for an example.	1436	See C<poll_cb> for an example.
1060		1437
1061	=item IO::AIO::poll_cb	1438	=item IO::AIO::poll_cb
1062		1439
1063	Process some outstanding events on the result pipe. You have to call this	1440	Process some outstanding events on the result pipe. You have to call
1064	regularly. Returns the number of events processed. Returns immediately	1441	this regularly. Returns C<0> if all events could be processed (or there
1065	when no events are outstanding. The amount of events processed depends on	1442	were no events to process), or C<-1> if it returned earlier for whatever
1066	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1443	reason. Returns immediately when no events are outstanding. The amount of
		1444	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1445	C<IO::AIO::max_poll_time>.
1067		1446
1068	If not all requests were processed for whatever reason, the filehandle	1447	If not all requests were processed for whatever reason, the filehandle
1069	will still be ready when C<poll_cb> returns.	1448	will still be ready when C<poll_cb> returns, so normally you don't have to
		1449	do anything special to have it called later.
		1450
		1451	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1452	ready, it can be beneficial to call this function from loops which submit
		1453	a lot of requests, to make sure the results get processed when they become
		1454	available and not just when the loop is finished and the event loop takes
		1455	over again. This function returns very fast when there are no outstanding
		1456	requests.
1070		1457
1071	Example: Install an Event watcher that automatically calls	1458	Example: Install an Event watcher that automatically calls
1072	IO::AIO::poll_cb with high priority:	1459	IO::AIO::poll_cb with high priority (more examples can be found in the
		1460	SYNOPSIS section, at the top of this document):
1073		1461
1074	Event->io (fd => IO::AIO::poll_fileno,	1462	Event->io (fd => IO::AIO::poll_fileno,
1075	poll => 'r', async => 1,	1463	poll => 'r', async => 1,
1076	cb => \&IO::AIO::poll_cb);	1464	cb => \&IO::AIO::poll_cb);
		1465
		1466	=item IO::AIO::poll_wait
		1467
		1468	If there are any outstanding requests and none of them in the result
		1469	phase, wait till the result filehandle becomes ready for reading (simply
		1470	does a C<select> on the filehandle. This is useful if you want to
		1471	synchronously wait for some requests to finish).
		1472
		1473	See C<nreqs> for an example.
		1474
		1475	=item IO::AIO::poll
		1476
		1477	Waits until some requests have been handled.
		1478
		1479	Returns the number of requests processed, but is otherwise strictly
		1480	equivalent to:
		1481
		1482	IO::AIO::poll_wait, IO::AIO::poll_cb
		1483
		1484	=item IO::AIO::flush
		1485
		1486	Wait till all outstanding AIO requests have been handled.
		1487
		1488	Strictly equivalent to:
		1489
		1490	IO::AIO::poll_wait, IO::AIO::poll_cb
		1491	while IO::AIO::nreqs;
1077		1492
1078	=item IO::AIO::max_poll_reqs $nreqs	1493	=item IO::AIO::max_poll_reqs $nreqs
1079		1494
1080	=item IO::AIO::max_poll_time $seconds	1495	=item IO::AIO::max_poll_time $seconds
1081		1496
…		…
1106	# use a low priority so other tasks have priority	1521	# use a low priority so other tasks have priority
1107	Event->io (fd => IO::AIO::poll_fileno,	1522	Event->io (fd => IO::AIO::poll_fileno,
1108	poll => 'r', nice => 1,	1523	poll => 'r', nice => 1,
1109	cb => &IO::AIO::poll_cb);	1524	cb => &IO::AIO::poll_cb);
1110		1525
1111	=item IO::AIO::poll_wait
1112
1113	If there are any outstanding requests and none of them in the result
1114	phase, wait till the result filehandle becomes ready for reading (simply
1115	does a C<select> on the filehandle. This is useful if you want to
1116	synchronously wait for some requests to finish).
1117
1118	See C<nreqs> for an example.
1119
1120	=item IO::AIO::poll
1121
1122	Waits until some requests have been handled.
1123
1124	Returns the number of requests processed, but is otherwise strictly
1125	equivalent to:
1126
1127	IO::AIO::poll_wait, IO::AIO::poll_cb
1128
1129	=item IO::AIO::flush
1130
1131	Wait till all outstanding AIO requests have been handled.
1132
1133	Strictly equivalent to:
1134
1135	IO::AIO::poll_wait, IO::AIO::poll_cb
1136	while IO::AIO::nreqs;
1137
1138	=back	1526	=back
1139		1527
1140	=head3 CONTROLLING THE NUMBER OF THREADS	1528	=head3 CONTROLLING THE NUMBER OF THREADS
1141		1529
1142	=over	1530	=over
…		…
1175		1563
1176	Under normal circumstances you don't need to call this function.	1564	Under normal circumstances you don't need to call this function.
1177		1565
1178	=item IO::AIO::max_idle $nthreads	1566	=item IO::AIO::max_idle $nthreads
1179		1567
1180	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1568	Limit the number of threads (default: 4) that are allowed to idle
1181	threads that did not get a request to process within 10 seconds). That	1569	(i.e., threads that did not get a request to process within the idle
1182	means if a thread becomes idle while C<$nthreads> other threads are also	1570	timeout (default: 10 seconds). That means if a thread becomes idle while
1183	idle, it will free its resources and exit.	1571	C<$nthreads> other threads are also idle, it will free its resources and
		1572	exit.
1184		1573
1185	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1574	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1186	to allow for extremely high load situations, but want to free resources	1575	to allow for extremely high load situations, but want to free resources
1187	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1576	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1188		1577
1189	The default is probably ok in most situations, especially if thread	1578	The default is probably ok in most situations, especially if thread
1190	creation is fast. If thread creation is very slow on your system you might	1579	creation is fast. If thread creation is very slow on your system you might
1191	want to use larger values.	1580	want to use larger values.
1192		1581
		1582	=item IO::AIO::idle_timeout $seconds
		1583
		1584	Sets the minimum idle timeout (default 10) after which worker threads are
		1585	allowed to exit. SEe C<IO::AIO::max_idle>.
		1586
1193	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1587	=item IO::AIO::max_outstanding $maxreqs
		1588
		1589	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1590	you do queue up more than this number of requests, the next call to
		1591	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1592	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1593	longer exceeded.
		1594
		1595	In other words, this setting does not enforce a queue limit, but can be
		1596	used to make poll functions block if the limit is exceeded.
1194		1597
1195	This is a very bad function to use in interactive programs because it	1598	This is a very bad function to use in interactive programs because it
1196	blocks, and a bad way to reduce concurrency because it is inexact: Better	1599	blocks, and a bad way to reduce concurrency because it is inexact: Better
1197	use an C<aio_group> together with a feed callback.	1600	use an C<aio_group> together with a feed callback.
1198		1601
1199	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1602	It's main use is in scripts without an event loop - when you want to stat
1200	to queue up more than this number of requests, the next call to the	1603	a lot of files, you can write somehting like this:
1201	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1202	function will block until the limit is no longer exceeded.
1203		1604
1204	The default value is very large, so there is no practical limit on the	1605	IO::AIO::max_outstanding 32;
1205	number of outstanding requests.
1206		1606
1207	You can still queue as many requests as you want. Therefore,	1607	for my $path (...) {
1208	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1608	aio_stat $path , ...;
1209	as a stop gap to shield against fatal memory overflow (with large values).	1609	IO::AIO::poll_cb;
		1610	}
		1611
		1612	IO::AIO::flush;
		1613
		1614	The call to C<poll_cb> inside the loop will normally return instantly, but
		1615	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1616	some requests have been handled. This keeps the loop from pushing a large
		1617	number of C<aio_stat> requests onto the queue.
		1618
		1619	The default value for C<max_outstanding> is very large, so there is no
		1620	practical limit on the number of outstanding requests.
1210		1621
1211	=back	1622	=back
1212		1623
1213	=head3 STATISTICAL INFORMATION	1624	=head3 STATISTICAL INFORMATION
1214		1625
…		…
1234	Returns the number of requests currently in the pending state (executed,	1645	Returns the number of requests currently in the pending state (executed,
1235	but not yet processed by poll_cb).	1646	but not yet processed by poll_cb).
1236		1647
1237	=back	1648	=back
1238		1649
		1650	=head3 MISCELLANEOUS FUNCTIONS
		1651
		1652	IO::AIO implements some functions that might be useful, but are not
		1653	asynchronous.
		1654
		1655	=over 4
		1656
		1657	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1658
		1659	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1660	but is blocking (this makes most sense if you know the input data is
		1661	likely cached already and the output filehandle is set to non-blocking
		1662	operations).
		1663
		1664	Returns the number of bytes copied, or C<-1> on error.
		1665
		1666	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1667
		1668	Simply calls the C<posix_fadvise> function (see its
		1669	manpage for details). The following advice constants are
		1670	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1671	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1672	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1673
		1674	On systems that do not implement C<posix_fadvise>, this function returns
		1675	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1676
		1677	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1678
		1679	Simply calls the C<posix_madvise> function (see its
		1680	manpage for details). The following advice constants are
		1681	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1682	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1683
		1684	On systems that do not implement C<posix_madvise>, this function returns
		1685	ENOSYS, otherwise the return value of C<posix_madvise>.
		1686
		1687	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1688
		1689	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1690	$scalar (see its manpage for details). The following protect
		1691	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1692	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1693
		1694	On systems that do not implement C<mprotect>, this function returns
		1695	ENOSYS, otherwise the return value of C<mprotect>.
		1696
		1697	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1698
		1699	Memory-maps a file (or anonymous memory range) and attaches it to the
		1700	given C<$scalar>, which will act like a string scalar.
		1701
		1702	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1703	change the string length, and most read-only operations such as copying it
		1704	or searching it with regexes and so on.
		1705
		1706	Anything else is unsafe and will, at best, result in memory leaks.
		1707
		1708	The memory map associated with the C<$scalar> is automatically removed
		1709	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1710	C<IO::AIO::munmap> functions are called.
		1711
		1712	This calls the C<mmap>(2) function internally. See your system's manual
		1713	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1714
		1715	The C<$length> must be larger than zero and smaller than the actual
		1716	filesize.
		1717
		1718	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1719	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1720
		1721	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1722	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1723	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1724	(which is set to C<MAP_ANON> if your system only provides this
		1725	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1726	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1727	C<IO::AIO::MAP_NONBLOCK>
		1728
		1729	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1730
		1731	C<$offset> is the offset from the start of the file - it generally must be
		1732	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1733
		1734	Example:
		1735
		1736	use Digest::MD5;
		1737	use IO::AIO;
		1738
		1739	open my $fh, "<verybigfile"
		1740	or die "$!";
		1741
		1742	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1743	or die "verybigfile: $!";
		1744
		1745	my $fast_md5 = md5 $data;
		1746
		1747	=item IO::AIO::munmap $scalar
		1748
		1749	Removes a previous mmap and undefines the C<$scalar>.
		1750
		1751	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1752
		1753	Calls the C<munlock> function, undoing the effects of a previous
		1754	C<aio_mlock> call (see its description for details).
		1755
		1756	=item IO::AIO::munlockall
		1757
		1758	Calls the C<munlockall> function.
		1759
		1760	On systems that do not implement C<munlockall>, this function returns
		1761	ENOSYS, otherwise the return value of C<munlockall>.
		1762
		1763	=back
		1764
1239	=cut	1765	=cut
1240		1766
1241	# support function to convert a fd into a perl filehandle
1242	sub _fd2fh {
1243	return undef if $_[0] < 0;
1244
1245	# try to generate nice filehandles
1246	my $sym = "IO::AIO::fd#$_[0]";
1247	local *$sym;
1248
1249	open *$sym, "+<&=$_[0]" # usually works under any unix
1250	or open *$sym, "<&=$_[0]" # cygwin needs this
1251	or open *$sym, ">&=$_[0]" # or this
1252	or return undef;
1253
1254	*$sym
1255	}
1256
1257	min_parallel 8;	1767	min_parallel 8;
1258		1768
1259	END { flush }	1769	END { flush }
1260		1770
1261	1;	1771	1;
1262		1772
		1773	=head1 EVENT LOOP INTEGRATION
		1774
		1775	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1776	automatically into many event loops:
		1777
		1778	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1779	use AnyEvent::AIO;
		1780
		1781	You can also integrate IO::AIO manually into many event loops, here are
		1782	some examples of how to do this:
		1783
		1784	# EV integration
		1785	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1786
		1787	# Event integration
		1788	Event->io (fd => IO::AIO::poll_fileno,
		1789	poll => 'r',
		1790	cb => \&IO::AIO::poll_cb);
		1791
		1792	# Glib/Gtk2 integration
		1793	add_watch Glib::IO IO::AIO::poll_fileno,
		1794	in => sub { IO::AIO::poll_cb; 1 };
		1795
		1796	# Tk integration
		1797	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1798	readable => \&IO::AIO::poll_cb);
		1799
		1800	# Danga::Socket integration
		1801	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1802	\&IO::AIO::poll_cb);
		1803
1263	=head2 FORK BEHAVIOUR	1804	=head2 FORK BEHAVIOUR
1264		1805
1265	This module should do "the right thing" when the process using it forks:	1806	Usage of pthreads in a program changes the semantics of fork
		1807	considerably. Specifically, only async-safe functions can be called after
		1808	fork. Perl doesn't know about this, so in general, you cannot call fork
		1809	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		1810	pthreads, so this applies, but many other extensions and (for inexplicable
		1811	reasons) perl itself often is linked against pthreads, so this limitation
		1812	applies to quite a lot of perls.
1266		1813
1267	Before the fork, IO::AIO enters a quiescent state where no requests	1814	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1268	can be added in other threads and no results will be processed. After	1815	only works in the process that loaded it. Forking is fully supported, but
1269	the fork the parent simply leaves the quiescent state and continues	1816	using IO::AIO in the child is not.
1270	request/result processing, while the child frees the request/result queue
1271	(so that the requests started before the fork will only be handled in the
1272	parent). Threads will be started on demand until the limit set in the
1273	parent process has been reached again.
1274		1817
1275	In short: the parent will, after a short pause, continue as if fork had	1818	You might get around by not I<using> IO::AIO before (or after)
1276	not been called, while the child will act as if IO::AIO has not been used	1819	forking. You could also try to call the L<IO::AIO::reinit> function in the
1277	yet.	1820	child:
		1821
		1822	=over 4
		1823
		1824	=item IO::AIO::reinit
		1825
		1826	Abondons all current requests and I/O threads and simply reinitialises all
		1827	data structures. This is not an operation suppported by any standards, but
		1828	happens to work on GNU/Linux and some newer BSD systems.
		1829
		1830	The only reasonable use for this function is to call it after forking, if
		1831	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1832	the process will result in undefined behaviour. Calling it at any time
		1833	will also result in any undefined (by POSIX) behaviour.
		1834
		1835	=back
1278		1836
1279	=head2 MEMORY USAGE	1837	=head2 MEMORY USAGE
1280		1838
1281	Per-request usage:	1839	Per-request usage:
1282		1840
…		…
1284	bytes of memory. In addition, stat requests need a stat buffer (possibly	1842	bytes of memory. In addition, stat requests need a stat buffer (possibly
1285	a few hundred bytes), readdir requires a result buffer and so on. Perl	1843	a few hundred bytes), readdir requires a result buffer and so on. Perl
1286	scalars and other data passed into aio requests will also be locked and	1844	scalars and other data passed into aio requests will also be locked and
1287	will consume memory till the request has entered the done state.	1845	will consume memory till the request has entered the done state.
1288		1846
1289	This is now awfully much, so queuing lots of requests is not usually a	1847	This is not awfully much, so queuing lots of requests is not usually a
1290	problem.	1848	problem.
1291		1849
1292	Per-thread usage:	1850	Per-thread usage:
1293		1851
1294	In the execution phase, some aio requests require more memory for	1852	In the execution phase, some aio requests require more memory for
…		…
1299		1857
1300	Known bugs will be fixed in the next release.	1858	Known bugs will be fixed in the next release.
1301		1859
1302	=head1 SEE ALSO	1860	=head1 SEE ALSO
1303		1861
1304	L<Coro::AIO>.	1862	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1863	more natural syntax.
1305		1864
1306	=head1 AUTHOR	1865	=head1 AUTHOR
1307		1866
1308	Marc Lehmann <schmorp@schmorp.de>	1867	Marc Lehmann <schmorp@schmorp.de>
1309	http://home.schmorp.de/	1868	http://home.schmorp.de/

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