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Revision 1.110 by root, Sun Jul 8 09:09:34 2007 UTC vs.
Revision 1.207 by root, Mon Jul 25 16:50:33 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
		178	aio_fsync aio_syncfs 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 aio_truncate);	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_syncfs $fh, $callback->($status)
		243	aio_fsync $fh, $callback->($status)
		244	aio_fdatasync $fh, $callback->($status)
		245	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		246	aio_pathsync $path, $callback->($status)
		247	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		248	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		249	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		250	aio_mlockall $flags, $callback->($status)
		251	aio_group $callback->(...)
		252	aio_nop $callback->()
		253
		254	$prev_pri = aioreq_pri [$pri]
		255	aioreq_nice $pri_adjust
		256
		257	IO::AIO::poll_wait
		258	IO::AIO::poll_cb
		259	IO::AIO::poll
		260	IO::AIO::flush
		261	IO::AIO::max_poll_reqs $nreqs
		262	IO::AIO::max_poll_time $seconds
		263	IO::AIO::min_parallel $nthreads
		264	IO::AIO::max_parallel $nthreads
		265	IO::AIO::max_idle $nthreads
		266	IO::AIO::idle_timeout $seconds
		267	IO::AIO::max_outstanding $maxreqs
		268	IO::AIO::nreqs
		269	IO::AIO::nready
		270	IO::AIO::npending
		271
		272	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		273	IO::AIO::fadvise $fh, $offset, $len, $advice
		274	IO::AIO::madvise $scalar, $offset, $length, $advice
		275	IO::AIO::mprotect $scalar, $offset, $length, $protect
		276	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		277	IO::AIO::munlockall
214		278
215	=head2 AIO REQUEST FUNCTIONS	279	=head2 AIO REQUEST FUNCTIONS
216		280
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	281	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	282	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	283	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	284	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	285	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	286	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	287	syscall has been executed asynchronously.
224		288
225	All functions expecting a filehandle keep a copy of the filehandle	289	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	290	internally until the request has finished.
227		291
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	305	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)	306	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	307	use something else to ensure your scalar has the correct contents.
244		308
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	309	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	310	handles correctly whether it is set or not.
247		311
248	=over 4	312	=over 4
249		313
250	=item $prev_pri = aioreq_pri [$pri]	314	=item $prev_pri = aioreq_pri [$pri]
251		315
…		…
298	by the umask in effect then the request is being executed, so better never	362	by the umask in effect then the request is being executed, so better never
299	change the umask.	363	change the umask.
300		364
301	Example:	365	Example:
302		366
303	aio_open "/etc/passwd", O_RDONLY, 0, sub {	367	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
304	if ($_[0]) {	368	if ($_[0]) {
305	print "open successful, fh is $_[0]\n";	369	print "open successful, fh is $_[0]\n";
306	...	370	...
307	} else {	371	} else {
308	die "open failed: $!\n";	372	die "open failed: $!\n";
309	}	373	}
310	};	374	};
311		375
		376	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		377	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		378	following POSIX and non-POSIX constants are available (missing ones on
		379	your system are, as usual, C<0>):
		380
		381	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		382	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		383	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		384
312		385
313	=item aio_close $fh, $callback->($status)	386	=item aio_close $fh, $callback->($status)
314		387
315	Asynchronously close a file and call the callback with the result	388	Asynchronously close a file and call the callback with the result
316	code. I<WARNING:> although accepted, you should not pass in a perl	389	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		390
321	This is supposed to be a bug in the API, so that might change. It's	391	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
322	therefore best to avoid this function.	392	closing the file descriptor associated with the filehandle itself.
323		393
		394	Therefore, C<aio_close> will not close the filehandle - instead it will
		395	use dup2 to overwrite the file descriptor with the write-end of a pipe
		396	(the pipe fd will be created on demand and will be cached).
		397
		398	Or in other words: the file descriptor will be closed, but it will not be
		399	free for reuse until the perl filehandle is closed.
		400
		401	=cut
324		402
325	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	403	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
326		404
327	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	405	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
328		406
329	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>	407	Reads or writes C<$length> bytes from or to the specified C<$fh> and
330	into the scalar given by C<$data> and offset C<$dataoffset> and calls the	408	C<$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	409	and calls the callback without the actual number of bytes read (or -1 on
332	like the syscall).	410	error, just like the syscall).
333		411
		412	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		413	offset plus the actual number of bytes read.
		414
334	If C<$offset> is undefined, then the current file offset will be used (and	415	If C<$offset> is undefined, then the current file descriptor offset will
335	updated), otherwise the file offset will not be changed by these calls.	416	be used (and updated), otherwise the file descriptor offset will not be
		417	changed by these calls.
336		418
337	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.	419	If C<$length> is undefined in C<aio_write>, use the remaining length of
		420	C<$data>.
338		421
339	If C<$dataoffset> is less than zero, it will be counted from the end of	422	If C<$dataoffset> is less than zero, it will be counted from the end of
340	C<$data>.	423	C<$data>.
341		424
342	The C<$data> scalar I<MUST NOT> be modified in any way while the request	425	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
356		439
357	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	440	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
358	reading at byte offset C<$in_offset>, and starts writing at the current	441	reading at byte offset C<$in_offset>, and starts writing at the current
359	file offset of C<$out_fh>. Because of that, it is not safe to issue more	442	file offset of C<$out_fh>. Because of that, it is not safe to issue more
360	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	443	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
361	other.	444	other. The same C<$in_fh> works fine though, as this function does not
		445	move or use the file offset of C<$in_fh>.
362		446
		447	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		448	are written, and there is no way to find out how many more bytes have been
		449	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		450	number of bytes written to C<$out_fh>. Only if the result value equals
		451	C<$length> one can assume that C<$length> bytes have been read.
		452
		453	Unlike with other C<aio_> functions, it makes a lot of sense to use
		454	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		455	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		456	the socket I/O will be non-blocking. Note, however, that you can run
		457	into a trap where C<aio_sendfile> reads some data with readahead, then
		458	fails to write all data, and when the socket is ready the next time, the
		459	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		460	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		461	resource usage.
		462
363	This call tries to make use of a native C<sendfile> syscall to provide	463	This call tries to make use of a native C<sendfile>-like syscall to
364	zero-copy operation. For this to work, C<$out_fh> should refer to a	464	provide zero-copy operation. For this to work, C<$out_fh> should refer to
365	socket, and C<$in_fh> should refer to mmap'able file.	465	a socket, and C<$in_fh> should refer to an mmap'able file.
366		466
367	If the native sendfile call fails or is not implemented, it will be	467	If a native sendfile cannot be found or it fails with C<ENOSYS>,
368	emulated, so you can call C<aio_sendfile> on any type of filehandle	468	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		469	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
369	regardless of the limitations of the operating system.	470	type of filehandle regardless of the limitations of the operating system.
370		471
371	Please note, however, that C<aio_sendfile> can read more bytes from	472	As native sendfile syscalls (as practically any non-POSIX interface hacked
372	C<$in_fh> than are written, and there is no way to find out how many	473	together in a hurry to improve benchmark numbers) tend to be rather buggy
373	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	474	on many systems, this implementation tries to work around some known bugs
374	provides the number of bytes written to C<$out_fh>. Only if the result	475	in Linux and FreeBSD kernels (probably others, too), but that might fail,
375	value equals C<$length> one can assume that C<$length> bytes have been	476	so you really really should check the return value of C<aio_sendfile> -
376	read.	477	fewre bytes than expected might have been transferred.
377		478
378		479
379	=item aio_readahead $fh,$offset,$length, $callback->($retval)	480	=item aio_readahead $fh,$offset,$length, $callback->($retval)
380		481
381	C<aio_readahead> populates the page cache with data from a file so that	482	C<aio_readahead> populates the page cache with data from a file so that
…		…
404		505
405	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	506	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
406	error when stat'ing a large file, the results will be silently truncated	507	error when stat'ing a large file, the results will be silently truncated
407	unless perl itself is compiled with large file support.	508	unless perl itself is compiled with large file support.
408		509
		510	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		511	following constants and functions (if not implemented, the constants will
		512	be C<0> and the functions will either C<croak> or fall back on traditional
		513	behaviour).
		514
		515	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		516	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		517	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		518
409	Example: Print the length of F</etc/passwd>:	519	Example: Print the length of F</etc/passwd>:
410		520
411	aio_stat "/etc/passwd", sub {	521	aio_stat "/etc/passwd", sub {
412	$_[0] and die "stat failed: $!";	522	$_[0] and die "stat failed: $!";
413	print "size is ", -s _, "\n";	523	print "size is ", -s _, "\n";
414	};	524	};
415		525
416		526
		527	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		528
		529	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		530	whether a file handle or path was passed.
		531
		532	On success, the callback is passed a hash reference with the following
		533	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		534	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		535	is passed.
		536
		537	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		538	C<ST_NOSUID>.
		539
		540	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		541	their correct value when available, or to C<0> on systems that do
		542	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		543	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		544	C<ST_NODIRATIME> and C<ST_RELATIME>.
		545
		546	Example: stat C</wd> and dump out the data if successful.
		547
		548	aio_statvfs "/wd", sub {
		549	my $f = $_[0]
		550	or die "statvfs: $!";
		551
		552	use Data::Dumper;
		553	say Dumper $f;
		554	};
		555
		556	# result:
		557	{
		558	bsize => 1024,
		559	bfree => 4333064312,
		560	blocks => 10253828096,
		561	files => 2050765568,
		562	flag => 4096,
		563	favail => 2042092649,
		564	bavail => 4333064312,
		565	ffree => 2042092649,
		566	namemax => 255,
		567	frsize => 1024,
		568	fsid => 1810
		569	}
		570
		571
417	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	572	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
418		573
419	Works like perl's C<utime> function (including the special case of $atime	574	Works like perl's C<utime> function (including the special case of $atime
420	and $mtime being undef). Fractional times are supported if the underlying	575	and $mtime being undef). Fractional times are supported if the underlying
421	syscalls support them.	576	syscalls support them.
…		…
469		624
470	The only (POSIX-) portable way of calling this function is:	625	The only (POSIX-) portable way of calling this function is:
471		626
472	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	627	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
473		628
		629	See C<aio_stat> for info about some potentially helpful extra constants
		630	and functions.
474		631
475	=item aio_link $srcpath, $dstpath, $callback->($status)	632	=item aio_link $srcpath, $dstpath, $callback->($status)
476		633
477	Asynchronously create a new link to the existing object at C<$srcpath> at	634	Asynchronously create a new link to the existing object at C<$srcpath> at
478	the path C<$dstpath> and call the callback with the result code.	635	the path C<$dstpath> and call the callback with the result code.
…		…
489	Asynchronously read the symlink specified by C<$path> and pass it to	646	Asynchronously read the symlink specified by C<$path> and pass it to
490	the callback. If an error occurs, nothing or undef gets passed to the	647	the callback. If an error occurs, nothing or undef gets passed to the
491	callback.	648	callback.
492		649
493		650
		651	=item aio_realpath $path, $callback->($path)
		652
		653	Asynchronously make the path absolute and resolve any symlinks in
		654	C<$path>. The resulting path only consists of directories (Same as
		655	L<Cwd::realpath>).
		656
		657	This request can be used to get the absolute path of the current working
		658	directory by passing it a path of F<.> (a single dot).
		659
		660
494	=item aio_rename $srcpath, $dstpath, $callback->($status)	661	=item aio_rename $srcpath, $dstpath, $callback->($status)
495		662
496	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	663	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
497	rename(2) and call the callback with the result code.	664	rename(2) and call the callback with the result code.
498		665
…		…
514		681
515	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	682	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
516	directory (i.e. opendir + readdir + closedir). The entries will not be	683	directory (i.e. opendir + readdir + closedir). The entries will not be
517	sorted, and will B<NOT> include the C<.> and C<..> entries.	684	sorted, and will B<NOT> include the C<.> and C<..> entries.
518		685
519	The callback a single argument which is either C<undef> or an array-ref	686	The callback is passed a single argument which is either C<undef> or an
520	with the filenames.	687	array-ref with the filenames.
		688
		689
		690	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		691
		692	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
		693	tune behaviour and output format. In case of an error, C<$entries> will be
		694	C<undef>.
		695
		696	The flags are a combination of the following constants, ORed together (the
		697	flags will also be passed to the callback, possibly modified):
		698
		699	=over 4
		700
		701	=item IO::AIO::READDIR_DENTS
		702
		703	When this flag is off, then the callback gets an arrayref consisting of
		704	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		705	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		706	entry in more detail.
		707
		708	C<$name> is the name of the entry.
		709
		710	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		711
		712	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		713	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		714	C<IO::AIO::DT_WHT>.
		715
		716	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		717	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		718	scalars are read-only: you can not modify them.
		719
		720	C<$inode> is the inode number (which might not be exact on systems with 64
		721	bit inode numbers and 32 bit perls). This field has unspecified content on
		722	systems that do not deliver the inode information.
		723
		724	=item IO::AIO::READDIR_DIRS_FIRST
		725
		726	When this flag is set, then the names will be returned in an order where
		727	likely directories come first, in optimal stat order. This is useful when
		728	you need to quickly find directories, or you want to find all directories
		729	while avoiding to stat() each entry.
		730
		731	If the system returns type information in readdir, then this is used
		732	to find directories directly. Otherwise, likely directories are names
		733	beginning with ".", or otherwise names with no dots, of which names with
		734	short names are tried first.
		735
		736	=item IO::AIO::READDIR_STAT_ORDER
		737
		738	When this flag is set, then the names will be returned in an order
		739	suitable for stat()'ing each one. That is, when you plan to stat()
		740	all files in the given directory, then the returned order will likely
		741	be fastest.
		742
		743	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		744	the likely dirs come first, resulting in a less optimal stat order.
		745
		746	=item IO::AIO::READDIR_FOUND_UNKNOWN
		747
		748	This flag should not be set when calling C<aio_readdirx>. Instead, it
		749	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		750	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
		751	C<$type>'s are known, which can be used to speed up some algorithms.
		752
		753	=back
521		754
522		755
523	=item aio_load $path, $data, $callback->($status)	756	=item aio_load $path, $data, $callback->($status)
524		757
525	This is a composite request that tries to fully load the given file into	758	This is a composite request that tries to fully load the given file into
526	memory. Status is the same as with aio_read.	759	memory. Status is the same as with aio_read.
527		760
528	=cut	761	=cut
529		762
530	sub aio_load($$;$) {	763	sub aio_load($$;$) {
531	aio_block {
532	my ($path, undef, $cb) = @_;	764	my ($path, undef, $cb) = @_;
533	my $data = \$_[1];	765	my $data = \$_[1];
534		766
535	my $pri = aioreq_pri;	767	my $pri = aioreq_pri;
536	my $grp = aio_group $cb;	768	my $grp = aio_group $cb;
		769
		770	aioreq_pri $pri;
		771	add $grp aio_open $path, O_RDONLY, 0, sub {
		772	my $fh = shift
		773	or return $grp->result (-1);
537		774
538	aioreq_pri $pri;	775	aioreq_pri $pri;
539	add $grp aio_open $path, O_RDONLY, 0, sub {
540	my $fh = shift
541	or return $grp->result (-1);
542
543	aioreq_pri $pri;
544	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	776	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
545	$grp->result ($_[0]);	777	$grp->result ($_[0]);
546	};
547	};	778	};
548
549	$grp
550	}	779	};
		780
		781	$grp
551	}	782	}
552		783
553	=item aio_copy $srcpath, $dstpath, $callback->($status)	784	=item aio_copy $srcpath, $dstpath, $callback->($status)
554		785
555	Try to copy the I<file> (directories not supported as either source or	786	Try to copy the I<file> (directories not supported as either source or
556	destination) from C<$srcpath> to C<$dstpath> and call the callback with	787	destination) from C<$srcpath> to C<$dstpath> and call the callback with
557	the C<0> (error) or C<-1> ok.	788	a status of C<0> (ok) or C<-1> (error, see C<$!>).
558		789
559	This is a composite request that it creates the destination file with	790	This is a composite request that creates the destination file with
560	mode 0200 and copies the contents of the source file into it using	791	mode 0200 and copies the contents of the source file into it using
561	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	792	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
562	uid/gid, in that order.	793	uid/gid, in that order.
563		794
564	If an error occurs, the partial destination file will be unlinked, if	795	If an error occurs, the partial destination file will be unlinked, if
…		…
566	errors are being ignored.	797	errors are being ignored.
567		798
568	=cut	799	=cut
569		800
570	sub aio_copy($$;$) {	801	sub aio_copy($$;$) {
571	aio_block {
572	my ($src, $dst, $cb) = @_;	802	my ($src, $dst, $cb) = @_;
573		803
574	my $pri = aioreq_pri;	804	my $pri = aioreq_pri;
575	my $grp = aio_group $cb;	805	my $grp = aio_group $cb;
576		806
577	aioreq_pri $pri;	807	aioreq_pri $pri;
578	add $grp aio_open $src, O_RDONLY, 0, sub {	808	add $grp aio_open $src, O_RDONLY, 0, sub {
579	if (my $src_fh = $_[0]) {	809	if (my $src_fh = $_[0]) {
580	my @stat = stat $src_fh;	810	my @stat = stat $src_fh; # hmm, might block over nfs?
581		811
582	aioreq_pri $pri;	812	aioreq_pri $pri;
583	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	813	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
584	if (my $dst_fh = $_[0]) {	814	if (my $dst_fh = $_[0]) {
585	aioreq_pri $pri;	815	aioreq_pri $pri;
586	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	816	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
587	if ($_[0] == $stat[7]) {	817	if ($_[0] == $stat[7]) {
588	$grp->result (0);	818	$grp->result (0);
589	close $src_fh;	819	close $src_fh;
590		820
591	# those should not normally block. should. should.
592	utime $stat[8], $stat[9], $dst;
593	chmod $stat[2] & 07777, $dst_fh;
594	chown $stat[4], $stat[5], $dst_fh;
595	close $dst_fh;
596	} else {	821	my $ch = sub {
597	$grp->result (-1);
598	close $src_fh;
599	close $dst_fh;
600
601	aioreq $pri;	822	aioreq_pri $pri;
		823	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		824	aioreq_pri $pri;
		825	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		826	aioreq_pri $pri;
602	add $grp aio_unlink $dst;	827	add $grp aio_close $dst_fh;
		828	}
		829	};
603	}	830	};
		831
		832	aioreq_pri $pri;
		833	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		834	if ($_[0] < 0 && $! == ENOSYS) {
		835	aioreq_pri $pri;
		836	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		837	} else {
		838	$ch->();
		839	}
		840	};
		841	} else {
		842	$grp->result (-1);
		843	close $src_fh;
		844	close $dst_fh;
		845
		846	aioreq $pri;
		847	add $grp aio_unlink $dst;
604	};	848	}
605	} else {
606	$grp->result (-1);
607	}	849	};
		850	} else {
		851	$grp->result (-1);
608	},	852	}
609
610	} else {
611	$grp->result (-1);
612	}	853	},
		854
		855	} else {
		856	$grp->result (-1);
613	};	857	}
614
615	$grp
616	}	858	};
		859
		860	$grp
617	}	861	}
618		862
619	=item aio_move $srcpath, $dstpath, $callback->($status)	863	=item aio_move $srcpath, $dstpath, $callback->($status)
620		864
621	Try to move the I<file> (directories not supported as either source or	865	Try to move the I<file> (directories not supported as either source or
622	destination) from C<$srcpath> to C<$dstpath> and call the callback with	866	destination) from C<$srcpath> to C<$dstpath> and call the callback with
623	the C<0> (error) or C<-1> ok.	867	a status of C<0> (ok) or C<-1> (error, see C<$!>).
624		868
625	This is a composite request that tries to rename(2) the file first. If	869	This is a composite request that tries to rename(2) the file first; if
626	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	870	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
627	that is successful, unlinking the C<$srcpath>.	871	that is successful, unlinks the C<$srcpath>.
628		872
629	=cut	873	=cut
630		874
631	sub aio_move($$;$) {	875	sub aio_move($$;$) {
632	aio_block {
633	my ($src, $dst, $cb) = @_;	876	my ($src, $dst, $cb) = @_;
634		877
635	my $pri = aioreq_pri;	878	my $pri = aioreq_pri;
636	my $grp = aio_group $cb;	879	my $grp = aio_group $cb;
637		880
638	aioreq_pri $pri;	881	aioreq_pri $pri;
639	add $grp aio_rename $src, $dst, sub {	882	add $grp aio_rename $src, $dst, sub {
640	if ($_[0] && $! == EXDEV) {	883	if ($_[0] && $! == EXDEV) {
641	aioreq_pri $pri;	884	aioreq_pri $pri;
642	add $grp aio_copy $src, $dst, sub {	885	add $grp aio_copy $src, $dst, sub {
643	$grp->result ($_[0]);
644
645	if (!$_[0]) {
646	aioreq_pri $pri;
647	add $grp aio_unlink $src;
648	}
649	};
650	} else {
651	$grp->result ($_[0]);	886	$grp->result ($_[0]);
		887
		888	unless ($_[0]) {
		889	aioreq_pri $pri;
		890	add $grp aio_unlink $src;
		891	}
652	}	892	};
		893	} else {
		894	$grp->result ($_[0]);
653	};	895	}
654
655	$grp
656	}	896	};
		897
		898	$grp
657	}	899	}
658		900
659	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	901	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
660		902
661	Scans a directory (similar to C<aio_readdir>) but additionally tries to	903	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
681		923
682	Implementation notes.	924	Implementation notes.
683		925
684	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	926	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
685		927
		928	If readdir returns file type information, then this is used directly to
		929	find directories.
		930
686	After reading the directory, the modification time, size etc. of the	931	Otherwise, after reading the directory, the modification time, size etc.
687	directory before and after the readdir is checked, and if they match (and	932	of the directory before and after the readdir is checked, and if they
688	isn't the current time), the link count will be used to decide how many	933	match (and isn't the current time), the link count will be used to decide
689	entries are directories (if >= 2). Otherwise, no knowledge of the number	934	how many entries are directories (if >= 2). Otherwise, no knowledge of the
690	of subdirectories will be assumed.	935	number of subdirectories will be assumed.
691		936
692	Then entries will be sorted into likely directories (everything without	937	Then entries will be sorted into likely directories a non-initial dot
693	a non-initial dot currently) and likely non-directories (everything	938	currently) and likely non-directories (see C<aio_readdirx>). Then every
694	else). Then every entry plus an appended C</.> will be C<stat>'ed,	939	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
695	likely directories first. If that succeeds, it assumes that the entry	940	in order of their inode numbers. If that succeeds, it assumes that the
696	is a directory or a symlink to directory (which will be checked	941	entry is a directory or a symlink to directory (which will be checked
697	seperately). This is often faster than stat'ing the entry itself because	942	separately). This is often faster than stat'ing the entry itself because
698	filesystems might detect the type of the entry without reading the inode	943	filesystems might detect the type of the entry without reading the inode
699	data (e.g. ext2fs filetype feature).	944	data (e.g. ext2fs filetype feature), even on systems that cannot return
		945	the filetype information on readdir.
700		946
701	If the known number of directories (link count - 2) has been reached, the	947	If the known number of directories (link count - 2) has been reached, the
702	rest of the entries is assumed to be non-directories.	948	rest of the entries is assumed to be non-directories.
703		949
704	This only works with certainty on POSIX (= UNIX) filesystems, which	950	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
709	directory counting heuristic.	955	directory counting heuristic.
710		956
711	=cut	957	=cut
712		958
713	sub aio_scandir($$;$) {	959	sub aio_scandir($$;$) {
714	aio_block {
715	my ($path, $maxreq, $cb) = @_;	960	my ($path, $maxreq, $cb) = @_;
716		961
717	my $pri = aioreq_pri;	962	my $pri = aioreq_pri;
718		963
719	my $grp = aio_group $cb;	964	my $grp = aio_group $cb;
720		965
721	$maxreq = 4 if $maxreq <= 0;	966	$maxreq = 4 if $maxreq <= 0;
722		967
723	# stat once	968	# stat once
		969	aioreq_pri $pri;
		970	add $grp aio_stat $path, sub {
		971	return $grp->result () if $_[0];
		972	my $now = time;
		973	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		974
		975	# read the directory entries
724	aioreq_pri $pri;	976	aioreq_pri $pri;
725	add $grp aio_stat $path, sub {	977	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		978	my $entries = shift
726	return $grp->result () if $_[0];	979	or return $grp->result ();
727	my $now = time;
728	my $hash1 = join ":", (stat _)[0,1,3,7,9];
729		980
730	# read the directory entries	981	# stat the dir another time
731	aioreq_pri $pri;	982	aioreq_pri $pri;
732	add $grp aio_readdir $path, sub {
733	my $entries = shift
734	or return $grp->result ();
735
736	# stat the dir another time
737	aioreq_pri $pri;
738	add $grp aio_stat $path, sub {	983	add $grp aio_stat $path, sub {
739	my $hash2 = join ":", (stat _)[0,1,3,7,9];	984	my $hash2 = join ":", (stat _)[0,1,3,7,9];
740		985
741	my $ndirs;	986	my $ndirs;
742		987
743	# take the slow route if anything looks fishy	988	# take the slow route if anything looks fishy
744	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	989	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
745	$ndirs = -1;	990	$ndirs = -1;
746	} else {	991	} else {
747	# if nlink == 2, we are finished	992	# if nlink == 2, we are finished
748	# on non-posix-fs's, we rely on nlink < 2	993	# for non-posix-fs's, we rely on nlink < 2
749	$ndirs = (stat _)[3] - 2	994	$ndirs = (stat _)[3] - 2
750	or return $grp->result ([], $entries);	995	or return $grp->result ([], $entries);
751	}	996	}
752		997
753	# sort into likely dirs and likely nondirs
754	# dirs == files without ".", short entries first
755	$entries = [map $_->[0],
756	sort { $b->[1] cmp $a->[1] }
757	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
758	@$entries];
759
760	my (@dirs, @nondirs);	998	my (@dirs, @nondirs);
761		999
762	my $statgrp = add $grp aio_group sub {	1000	my $statgrp = add $grp aio_group sub {
763	$grp->result (\@dirs, \@nondirs);	1001	$grp->result (\@dirs, \@nondirs);
764	};	1002	};
765		1003
766	limit $statgrp $maxreq;	1004	limit $statgrp $maxreq;
767	feed $statgrp sub {	1005	feed $statgrp sub {
768	return unless @$entries;	1006	return unless @$entries;
769	my $entry = pop @$entries;	1007	my $entry = shift @$entries;
770		1008
771	aioreq_pri $pri;	1009	aioreq_pri $pri;
772	add $statgrp aio_stat "$path/$entry/.", sub {	1010	add $statgrp aio_stat "$path/$entry/.", sub {
773	if ($_[0] < 0) {	1011	if ($_[0] < 0) {
774	push @nondirs, $entry;	1012	push @nondirs, $entry;
775	} else {	1013	} else {
776	# need to check for real directory	1014	# need to check for real directory
777	aioreq_pri $pri;	1015	aioreq_pri $pri;
778	add $statgrp aio_lstat "$path/$entry", sub {	1016	add $statgrp aio_lstat "$path/$entry", sub {
779	if (-d _) {	1017	if (-d _) {
780	push @dirs, $entry;	1018	push @dirs, $entry;
781		1019
782	unless (--$ndirs) {	1020	unless (--$ndirs) {
783	push @nondirs, @$entries;	1021	push @nondirs, @$entries;
784	feed $statgrp;	1022	feed $statgrp;
785	}
786	} else {
787	push @nondirs, $entry;
788	}	1023	}
		1024	} else {
		1025	push @nondirs, $entry;
789	}	1026	}
790	}	1027	}
791	};	1028	}
792	};	1029	};
793	};	1030	};
794	};	1031	};
795	};	1032	};
796
797	$grp
798	}	1033	};
		1034
		1035	$grp
799	}	1036	}
800		1037
801	=item aio_rmtree $path, $callback->($status)	1038	=item aio_rmtree $path, $callback->($status)
802		1039
803	Delete a directory tree starting (and including) C<$path>, return the	1040	Delete a directory tree starting (and including) C<$path>, return the
…		…
807		1044
808	=cut	1045	=cut
809		1046
810	sub aio_rmtree;	1047	sub aio_rmtree;
811	sub aio_rmtree($;$) {	1048	sub aio_rmtree($;$) {
812	aio_block {
813	my ($path, $cb) = @_;	1049	my ($path, $cb) = @_;
814		1050
815	my $pri = aioreq_pri;	1051	my $pri = aioreq_pri;
816	my $grp = aio_group $cb;	1052	my $grp = aio_group $cb;
817		1053
818	aioreq_pri $pri;	1054	aioreq_pri $pri;
819	add $grp aio_scandir $path, 0, sub {	1055	add $grp aio_scandir $path, 0, sub {
820	my ($dirs, $nondirs) = @_;	1056	my ($dirs, $nondirs) = @_;
821		1057
822	my $dirgrp = aio_group sub {	1058	my $dirgrp = aio_group sub {
823	add $grp aio_rmdir $path, sub {	1059	add $grp aio_rmdir $path, sub {
824	$grp->result ($_[0]);	1060	$grp->result ($_[0]);
825	};
826	};	1061	};
827
828	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
829	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
830
831	add $grp $dirgrp;
832	};	1062	};
833		1063
834	$grp	1064	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1065	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1066
		1067	add $grp $dirgrp;
835	}	1068	};
		1069
		1070	$grp
836	}	1071	}
		1072
		1073	=item aio_sync $callback->($status)
		1074
		1075	Asynchronously call sync and call the callback when finished.
837		1076
838	=item aio_fsync $fh, $callback->($status)	1077	=item aio_fsync $fh, $callback->($status)
839		1078
840	Asynchronously call fsync on the given filehandle and call the callback	1079	Asynchronously call fsync on the given filehandle and call the callback
841	with the fsync result code.	1080	with the fsync result code.
…		…
845	Asynchronously call fdatasync on the given filehandle and call the	1084	Asynchronously call fdatasync on the given filehandle and call the
846	callback with the fdatasync result code.	1085	callback with the fdatasync result code.
847		1086
848	If this call isn't available because your OS lacks it or it couldn't be	1087	If this call isn't available because your OS lacks it or it couldn't be
849	detected, it will be emulated by calling C<fsync> instead.	1088	detected, it will be emulated by calling C<fsync> instead.
		1089
		1090	=item aio_syncfs $fh, $callback->($status)
		1091
		1092	Asynchronously call the syncfs syscall to sync the filesystem associated
		1093	to the given filehandle and call the callback with the syncfs result
		1094	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1095	errno to C<ENOSYS> nevertheless.
		1096
		1097	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1098
		1099	Sync the data portion of the file specified by C<$offset> and C<$length>
		1100	to disk (but NOT the metadata), by calling the Linux-specific
		1101	sync_file_range call. If sync_file_range is not available or it returns
		1102	ENOSYS, then fdatasync or fsync is being substituted.
		1103
		1104	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1105	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1106	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1107	manpage for details.
		1108
		1109	=item aio_pathsync $path, $callback->($status)
		1110
		1111	This request tries to open, fsync and close the given path. This is a
		1112	composite request intended to sync directories after directory operations
		1113	(E.g. rename). This might not work on all operating systems or have any
		1114	specific effect, but usually it makes sure that directory changes get
		1115	written to disc. It works for anything that can be opened for read-only,
		1116	not just directories.
		1117
		1118	Future versions of this function might fall back to other methods when
		1119	C<fsync> on the directory fails (such as calling C<sync>).
		1120
		1121	Passes C<0> when everything went ok, and C<-1> on error.
		1122
		1123	=cut
		1124
		1125	sub aio_pathsync($;$) {
		1126	my ($path, $cb) = @_;
		1127
		1128	my $pri = aioreq_pri;
		1129	my $grp = aio_group $cb;
		1130
		1131	aioreq_pri $pri;
		1132	add $grp aio_open $path, O_RDONLY, 0, sub {
		1133	my ($fh) = @_;
		1134	if ($fh) {
		1135	aioreq_pri $pri;
		1136	add $grp aio_fsync $fh, sub {
		1137	$grp->result ($_[0]);
		1138
		1139	aioreq_pri $pri;
		1140	add $grp aio_close $fh;
		1141	};
		1142	} else {
		1143	$grp->result (-1);
		1144	}
		1145	};
		1146
		1147	$grp
		1148	}
		1149
		1150	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1151
		1152	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1153	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1154	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1155	scalar must only be modified in-place while an aio operation is pending on
		1156	it).
		1157
		1158	It calls the C<msync> function of your OS, if available, with the memory
		1159	area starting at C<$offset> in the string and ending C<$length> bytes
		1160	later. If C<$length> is negative, counts from the end, and if C<$length>
		1161	is C<undef>, then it goes till the end of the string. The flags can be
		1162	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1163	C<IO::AIO::MS_SYNC>.
		1164
		1165	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1166
		1167	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1168	scalars.
		1169
		1170	It touches (reads or writes) all memory pages in the specified
		1171	range inside the scalar. All caveats and parameters are the same
		1172	as for C<aio_msync>, above, except for flags, which must be either
		1173	C<0> (which reads all pages and ensures they are instantiated) or
		1174	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1175	writing an octet from it, which dirties the page).
		1176
		1177	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1178
		1179	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1180	scalars.
		1181
		1182	It reads in all the pages of the underlying storage into memory (if any)
		1183	and locks them, so they are not getting swapped/paged out or removed.
		1184
		1185	If C<$length> is undefined, then the scalar will be locked till the end.
		1186
		1187	On systems that do not implement C<mlock>, this function returns C<-1>
		1188	and sets errno to C<ENOSYS>.
		1189
		1190	Note that the corresponding C<munlock> is synchronous and is
		1191	documented under L<MISCELLANEOUS FUNCTIONS>.
		1192
		1193	Example: open a file, mmap and mlock it - both will be undone when
		1194	C<$data> gets destroyed.
		1195
		1196	open my $fh, "<", $path or die "$path: $!";
		1197	my $data;
		1198	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1199	aio_mlock $data; # mlock in background
		1200
		1201	=item aio_mlockall $flags, $callback->($status)
		1202
		1203	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1204	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1205
		1206	On systems that do not implement C<mlockall>, this function returns C<-1>
		1207	and sets errno to C<ENOSYS>.
		1208
		1209	Note that the corresponding C<munlockall> is synchronous and is
		1210	documented under L<MISCELLANEOUS FUNCTIONS>.
		1211
		1212	Example: asynchronously lock all current and future pages into memory.
		1213
		1214	aio_mlockall IO::AIO::MCL_FUTURE;
850		1215
851	=item aio_group $callback->(...)	1216	=item aio_group $callback->(...)
852		1217
853	This is a very special aio request: Instead of doing something, it is a	1218	This is a very special aio request: Instead of doing something, it is a
854	container for other aio requests, which is useful if you want to bundle	1219	container for other aio requests, which is useful if you want to bundle
…		…
904	=item cancel $req	1269	=item cancel $req
905		1270
906	Cancels the request, if possible. Has the effect of skipping execution	1271	Cancels the request, if possible. Has the effect of skipping execution
907	when entering the B<execute> state and skipping calling the callback when	1272	when entering the B<execute> state and skipping calling the callback when
908	entering the the B<result> state, but will leave the request otherwise	1273	entering the the B<result> state, but will leave the request otherwise
909	untouched. That means that requests that currently execute will not be	1274	untouched (with the exception of readdir). That means that requests that
910	stopped and resources held by the request will not be freed prematurely.	1275	currently execute will not be stopped and resources held by the request
		1276	will not be freed prematurely.
911		1277
912	=item cb $req $callback->(...)	1278	=item cb $req $callback->(...)
913		1279
914	Replace (or simply set) the callback registered to the request.	1280	Replace (or simply set) the callback registered to the request.
915		1281
…		…
966	Their lifetime, simplified, looks like this: when they are empty, they	1332	Their lifetime, simplified, looks like this: when they are empty, they
967	will finish very quickly. If they contain only requests that are in the	1333	will finish very quickly. If they contain only requests that are in the
968	C<done> state, they will also finish. Otherwise they will continue to	1334	C<done> state, they will also finish. Otherwise they will continue to
969	exist.	1335	exist.
970		1336
971	That means after creating a group you have some time to add requests. And	1337	That means after creating a group you have some time to add requests
972	in the callbacks of those requests, you can add further requests to the	1338	(precisely before the callback has been invoked, which is only done within
973	group. And only when all those requests have finished will the the group	1339	the C<poll_cb>). And in the callbacks of those requests, you can add
974	itself finish.	1340	further requests to the group. And only when all those requests have
		1341	finished will the the group itself finish.
975		1342
976	=over 4	1343	=over 4
977		1344
978	=item add $grp ...	1345	=item add $grp ...
979		1346
…		…
988	=item $grp->cancel_subs	1355	=item $grp->cancel_subs
989		1356
990	Cancel all subrequests and clears any feeder, but not the group request	1357	Cancel all subrequests and clears any feeder, but not the group request
991	itself. Useful when you queued a lot of events but got a result early.	1358	itself. Useful when you queued a lot of events but got a result early.
992		1359
		1360	The group request will finish normally (you cannot add requests to the
		1361	group).
		1362
993	=item $grp->result (...)	1363	=item $grp->result (...)
994		1364
995	Set the result value(s) that will be passed to the group callback when all	1365	Set the result value(s) that will be passed to the group callback when all
996	subrequests have finished and set thre groups errno to the current value	1366	subrequests have finished and set the groups errno to the current value
997	of errno (just like calling C<errno> without an error number). By default,	1367	of errno (just like calling C<errno> without an error number). By default,
998	no argument will be passed and errno is zero.	1368	no argument will be passed and errno is zero.
999		1369
1000	=item $grp->errno ([$errno])	1370	=item $grp->errno ([$errno])
1001		1371
…		…
1012	=item feed $grp $callback->($grp)	1382	=item feed $grp $callback->($grp)
1013		1383
1014	Sets a feeder/generator on this group: every group can have an attached	1384	Sets a feeder/generator on this group: every group can have an attached
1015	generator that generates requests if idle. The idea behind this is that,	1385	generator that generates requests if idle. The idea behind this is that,
1016	although you could just queue as many requests as you want in a group,	1386	although you could just queue as many requests as you want in a group,
1017	this might starve other requests for a potentially long time. For	1387	this might starve other requests for a potentially long time. For example,
1018	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1388	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1019	requests, delaying any later requests for a long time.	1389	delaying any later requests for a long time.
1020		1390
1021	To avoid this, and allow incremental generation of requests, you can	1391	To avoid this, and allow incremental generation of requests, you can
1022	instead a group and set a feeder on it that generates those requests. The	1392	instead a group and set a feeder on it that generates those requests. The
1023	feed callback will be called whenever there are few enough (see C<limit>,	1393	feed callback will be called whenever there are few enough (see C<limit>,
1024	below) requests active in the group itself and is expected to queue more	1394	below) requests active in the group itself and is expected to queue more
…		…
1028	not impose any limits).	1398	not impose any limits).
1029		1399
1030	If the feed does not queue more requests when called, it will be	1400	If the feed does not queue more requests when called, it will be
1031	automatically removed from the group.	1401	automatically removed from the group.
1032		1402
1033	If the feed limit is C<0>, it will be set to C<2> automatically.	1403	If the feed limit is C<0> when this method is called, it will be set to
		1404	C<2> automatically.
1034		1405
1035	Example:	1406	Example:
1036		1407
1037	# stat all files in @files, but only ever use four aio requests concurrently:	1408	# stat all files in @files, but only ever use four aio requests concurrently:
1038		1409
…		…
1050	Sets the feeder limit for the group: The feeder will be called whenever	1421	Sets the feeder limit for the group: The feeder will be called whenever
1051	the group contains less than this many requests.	1422	the group contains less than this many requests.
1052		1423
1053	Setting the limit to C<0> will pause the feeding process.	1424	Setting the limit to C<0> will pause the feeding process.
1054		1425
		1426	The default value for the limit is C<0>, but note that setting a feeder
		1427	automatically bumps it up to C<2>.
		1428
1055	=back	1429	=back
1056		1430
1057	=head2 SUPPORT FUNCTIONS	1431	=head2 SUPPORT FUNCTIONS
1058		1432
1059	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1433	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1061	=over 4	1435	=over 4
1062		1436
1063	=item $fileno = IO::AIO::poll_fileno	1437	=item $fileno = IO::AIO::poll_fileno
1064		1438
1065	Return the I<request result pipe file descriptor>. This filehandle must be	1439	Return the I<request result pipe file descriptor>. This filehandle must be
1066	polled for reading by some mechanism outside this module (e.g. Event or	1440	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1067	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1441	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1068	to call C<poll_cb> to check the results.	1442	you have to call C<poll_cb> to check the results.
1069		1443
1070	See C<poll_cb> for an example.	1444	See C<poll_cb> for an example.
1071		1445
1072	=item IO::AIO::poll_cb	1446	=item IO::AIO::poll_cb
1073		1447
1074	Process some outstanding events on the result pipe. You have to call this	1448	Process some outstanding events on the result pipe. You have to call
1075	regularly. Returns the number of events processed. Returns immediately	1449	this regularly. Returns C<0> if all events could be processed (or there
1076	when no events are outstanding. The amount of events processed depends on	1450	were no events to process), or C<-1> if it returned earlier for whatever
1077	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1451	reason. Returns immediately when no events are outstanding. The amount of
		1452	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1453	C<IO::AIO::max_poll_time>.
1078		1454
1079	If not all requests were processed for whatever reason, the filehandle	1455	If not all requests were processed for whatever reason, the filehandle
1080	will still be ready when C<poll_cb> returns.	1456	will still be ready when C<poll_cb> returns, so normally you don't have to
		1457	do anything special to have it called later.
		1458
		1459	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1460	ready, it can be beneficial to call this function from loops which submit
		1461	a lot of requests, to make sure the results get processed when they become
		1462	available and not just when the loop is finished and the event loop takes
		1463	over again. This function returns very fast when there are no outstanding
		1464	requests.
1081		1465
1082	Example: Install an Event watcher that automatically calls	1466	Example: Install an Event watcher that automatically calls
1083	IO::AIO::poll_cb with high priority:	1467	IO::AIO::poll_cb with high priority (more examples can be found in the
		1468	SYNOPSIS section, at the top of this document):
1084		1469
1085	Event->io (fd => IO::AIO::poll_fileno,	1470	Event->io (fd => IO::AIO::poll_fileno,
1086	poll => 'r', async => 1,	1471	poll => 'r', async => 1,
1087	cb => \&IO::AIO::poll_cb);	1472	cb => \&IO::AIO::poll_cb);
		1473
		1474	=item IO::AIO::poll_wait
		1475
		1476	If there are any outstanding requests and none of them in the result
		1477	phase, wait till the result filehandle becomes ready for reading (simply
		1478	does a C<select> on the filehandle. This is useful if you want to
		1479	synchronously wait for some requests to finish).
		1480
		1481	See C<nreqs> for an example.
		1482
		1483	=item IO::AIO::poll
		1484
		1485	Waits until some requests have been handled.
		1486
		1487	Returns the number of requests processed, but is otherwise strictly
		1488	equivalent to:
		1489
		1490	IO::AIO::poll_wait, IO::AIO::poll_cb
		1491
		1492	=item IO::AIO::flush
		1493
		1494	Wait till all outstanding AIO requests have been handled.
		1495
		1496	Strictly equivalent to:
		1497
		1498	IO::AIO::poll_wait, IO::AIO::poll_cb
		1499	while IO::AIO::nreqs;
1088		1500
1089	=item IO::AIO::max_poll_reqs $nreqs	1501	=item IO::AIO::max_poll_reqs $nreqs
1090		1502
1091	=item IO::AIO::max_poll_time $seconds	1503	=item IO::AIO::max_poll_time $seconds
1092		1504
…		…
1117	# use a low priority so other tasks have priority	1529	# use a low priority so other tasks have priority
1118	Event->io (fd => IO::AIO::poll_fileno,	1530	Event->io (fd => IO::AIO::poll_fileno,
1119	poll => 'r', nice => 1,	1531	poll => 'r', nice => 1,
1120	cb => &IO::AIO::poll_cb);	1532	cb => &IO::AIO::poll_cb);
1121		1533
1122	=item IO::AIO::poll_wait
1123
1124	If there are any outstanding requests and none of them in the result
1125	phase, wait till the result filehandle becomes ready for reading (simply
1126	does a C<select> on the filehandle. This is useful if you want to
1127	synchronously wait for some requests to finish).
1128
1129	See C<nreqs> for an example.
1130
1131	=item IO::AIO::poll
1132
1133	Waits until some requests have been handled.
1134
1135	Returns the number of requests processed, but is otherwise strictly
1136	equivalent to:
1137
1138	IO::AIO::poll_wait, IO::AIO::poll_cb
1139
1140	=item IO::AIO::flush
1141
1142	Wait till all outstanding AIO requests have been handled.
1143
1144	Strictly equivalent to:
1145
1146	IO::AIO::poll_wait, IO::AIO::poll_cb
1147	while IO::AIO::nreqs;
1148
1149	=back	1534	=back
1150		1535
1151	=head3 CONTROLLING THE NUMBER OF THREADS	1536	=head3 CONTROLLING THE NUMBER OF THREADS
1152		1537
1153	=over	1538	=over
…		…
1186		1571
1187	Under normal circumstances you don't need to call this function.	1572	Under normal circumstances you don't need to call this function.
1188		1573
1189	=item IO::AIO::max_idle $nthreads	1574	=item IO::AIO::max_idle $nthreads
1190		1575
1191	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1576	Limit the number of threads (default: 4) that are allowed to idle
1192	threads that did not get a request to process within 10 seconds). That	1577	(i.e., threads that did not get a request to process within the idle
1193	means if a thread becomes idle while C<$nthreads> other threads are also	1578	timeout (default: 10 seconds). That means if a thread becomes idle while
1194	idle, it will free its resources and exit.	1579	C<$nthreads> other threads are also idle, it will free its resources and
		1580	exit.
1195		1581
1196	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1582	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1197	to allow for extremely high load situations, but want to free resources	1583	to allow for extremely high load situations, but want to free resources
1198	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1584	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1199		1585
1200	The default is probably ok in most situations, especially if thread	1586	The default is probably ok in most situations, especially if thread
1201	creation is fast. If thread creation is very slow on your system you might	1587	creation is fast. If thread creation is very slow on your system you might
1202	want to use larger values.	1588	want to use larger values.
1203		1589
		1590	=item IO::AIO::idle_timeout $seconds
		1591
		1592	Sets the minimum idle timeout (default 10) after which worker threads are
		1593	allowed to exit. SEe C<IO::AIO::max_idle>.
		1594
1204	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1595	=item IO::AIO::max_outstanding $maxreqs
		1596
		1597	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1598	you do queue up more than this number of requests, the next call to
		1599	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1600	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1601	longer exceeded.
		1602
		1603	In other words, this setting does not enforce a queue limit, but can be
		1604	used to make poll functions block if the limit is exceeded.
1205		1605
1206	This is a very bad function to use in interactive programs because it	1606	This is a very bad function to use in interactive programs because it
1207	blocks, and a bad way to reduce concurrency because it is inexact: Better	1607	blocks, and a bad way to reduce concurrency because it is inexact: Better
1208	use an C<aio_group> together with a feed callback.	1608	use an C<aio_group> together with a feed callback.
1209		1609
1210	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1610	It's main use is in scripts without an event loop - when you want to stat
1211	to queue up more than this number of requests, the next call to the	1611	a lot of files, you can write somehting like this:
1212	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1213	function will block until the limit is no longer exceeded.
1214		1612
1215	The default value is very large, so there is no practical limit on the	1613	IO::AIO::max_outstanding 32;
1216	number of outstanding requests.
1217		1614
1218	You can still queue as many requests as you want. Therefore,	1615	for my $path (...) {
1219	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1616	aio_stat $path , ...;
1220	as a stop gap to shield against fatal memory overflow (with large values).	1617	IO::AIO::poll_cb;
		1618	}
		1619
		1620	IO::AIO::flush;
		1621
		1622	The call to C<poll_cb> inside the loop will normally return instantly, but
		1623	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1624	some requests have been handled. This keeps the loop from pushing a large
		1625	number of C<aio_stat> requests onto the queue.
		1626
		1627	The default value for C<max_outstanding> is very large, so there is no
		1628	practical limit on the number of outstanding requests.
1221		1629
1222	=back	1630	=back
1223		1631
1224	=head3 STATISTICAL INFORMATION	1632	=head3 STATISTICAL INFORMATION
1225		1633
…		…
1245	Returns the number of requests currently in the pending state (executed,	1653	Returns the number of requests currently in the pending state (executed,
1246	but not yet processed by poll_cb).	1654	but not yet processed by poll_cb).
1247		1655
1248	=back	1656	=back
1249		1657
		1658	=head3 MISCELLANEOUS FUNCTIONS
		1659
		1660	IO::AIO implements some functions that might be useful, but are not
		1661	asynchronous.
		1662
		1663	=over 4
		1664
		1665	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1666
		1667	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1668	but is blocking (this makes most sense if you know the input data is
		1669	likely cached already and the output filehandle is set to non-blocking
		1670	operations).
		1671
		1672	Returns the number of bytes copied, or C<-1> on error.
		1673
		1674	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1675
		1676	Simply calls the C<posix_fadvise> function (see its
		1677	manpage for details). The following advice constants are
		1678	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1679	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1680	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1681
		1682	On systems that do not implement C<posix_fadvise>, this function returns
		1683	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1684
		1685	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1686
		1687	Simply calls the C<posix_madvise> function (see its
		1688	manpage for details). The following advice constants are
		1689	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1690	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1691
		1692	On systems that do not implement C<posix_madvise>, this function returns
		1693	ENOSYS, otherwise the return value of C<posix_madvise>.
		1694
		1695	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1696
		1697	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1698	$scalar (see its manpage for details). The following protect
		1699	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1700	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1701
		1702	On systems that do not implement C<mprotect>, this function returns
		1703	ENOSYS, otherwise the return value of C<mprotect>.
		1704
		1705	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1706
		1707	Memory-maps a file (or anonymous memory range) and attaches it to the
		1708	given C<$scalar>, which will act like a string scalar.
		1709
		1710	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1711	change the string length, and most read-only operations such as copying it
		1712	or searching it with regexes and so on.
		1713
		1714	Anything else is unsafe and will, at best, result in memory leaks.
		1715
		1716	The memory map associated with the C<$scalar> is automatically removed
		1717	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1718	C<IO::AIO::munmap> functions are called.
		1719
		1720	This calls the C<mmap>(2) function internally. See your system's manual
		1721	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1722
		1723	The C<$length> must be larger than zero and smaller than the actual
		1724	filesize.
		1725
		1726	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1727	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1728
		1729	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1730	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1731	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1732	(which is set to C<MAP_ANON> if your system only provides this
		1733	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1734	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1735	C<IO::AIO::MAP_NONBLOCK>
		1736
		1737	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1738
		1739	C<$offset> is the offset from the start of the file - it generally must be
		1740	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1741
		1742	Example:
		1743
		1744	use Digest::MD5;
		1745	use IO::AIO;
		1746
		1747	open my $fh, "<verybigfile"
		1748	or die "$!";
		1749
		1750	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1751	or die "verybigfile: $!";
		1752
		1753	my $fast_md5 = md5 $data;
		1754
		1755	=item IO::AIO::munmap $scalar
		1756
		1757	Removes a previous mmap and undefines the C<$scalar>.
		1758
		1759	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1760
		1761	Calls the C<munlock> function, undoing the effects of a previous
		1762	C<aio_mlock> call (see its description for details).
		1763
		1764	=item IO::AIO::munlockall
		1765
		1766	Calls the C<munlockall> function.
		1767
		1768	On systems that do not implement C<munlockall>, this function returns
		1769	ENOSYS, otherwise the return value of C<munlockall>.
		1770
		1771	=back
		1772
1250	=cut	1773	=cut
1251		1774
1252	# support function to convert a fd into a perl filehandle
1253	sub _fd2fh {
1254	return undef if $_[0] < 0;
1255
1256	# try to generate nice filehandles
1257	my $sym = "IO::AIO::fd#$_[0]";
1258	local *$sym;
1259
1260	open *$sym, "+<&=$_[0]" # usually works under any unix
1261	or open *$sym, "<&=$_[0]" # cygwin needs this
1262	or open *$sym, ">&=$_[0]" # or this
1263	or return undef;
1264
1265	*$sym
1266	}
1267
1268	min_parallel 8;	1775	min_parallel 8;
1269		1776
1270	END { flush }	1777	END { flush }
1271		1778
1272	1;	1779	1;
1273		1780
		1781	=head1 EVENT LOOP INTEGRATION
		1782
		1783	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1784	automatically into many event loops:
		1785
		1786	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1787	use AnyEvent::AIO;
		1788
		1789	You can also integrate IO::AIO manually into many event loops, here are
		1790	some examples of how to do this:
		1791
		1792	# EV integration
		1793	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1794
		1795	# Event integration
		1796	Event->io (fd => IO::AIO::poll_fileno,
		1797	poll => 'r',
		1798	cb => \&IO::AIO::poll_cb);
		1799
		1800	# Glib/Gtk2 integration
		1801	add_watch Glib::IO IO::AIO::poll_fileno,
		1802	in => sub { IO::AIO::poll_cb; 1 };
		1803
		1804	# Tk integration
		1805	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1806	readable => \&IO::AIO::poll_cb);
		1807
		1808	# Danga::Socket integration
		1809	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1810	\&IO::AIO::poll_cb);
		1811
1274	=head2 FORK BEHAVIOUR	1812	=head2 FORK BEHAVIOUR
1275		1813
1276	This module should do "the right thing" when the process using it forks:	1814	Usage of pthreads in a program changes the semantics of fork
		1815	considerably. Specifically, only async-safe functions can be called after
		1816	fork. Perl doesn't know about this, so in general, you cannot call fork
		1817	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		1818	pthreads, so this applies, but many other extensions and (for inexplicable
		1819	reasons) perl itself often is linked against pthreads, so this limitation
		1820	applies to quite a lot of perls.
1277		1821
1278	Before the fork, IO::AIO enters a quiescent state where no requests	1822	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1279	can be added in other threads and no results will be processed. After	1823	only works in the process that loaded it. Forking is fully supported, but
1280	the fork the parent simply leaves the quiescent state and continues	1824	using IO::AIO in the child is not.
1281	request/result processing, while the child frees the request/result queue
1282	(so that the requests started before the fork will only be handled in the
1283	parent). Threads will be started on demand until the limit set in the
1284	parent process has been reached again.
1285		1825
1286	In short: the parent will, after a short pause, continue as if fork had	1826	You might get around by not I<using> IO::AIO before (or after)
1287	not been called, while the child will act as if IO::AIO has not been used	1827	forking. You could also try to call the L<IO::AIO::reinit> function in the
1288	yet.	1828	child:
		1829
		1830	=over 4
		1831
		1832	=item IO::AIO::reinit
		1833
		1834	Abandons all current requests and I/O threads and simply reinitialises all
		1835	data structures. This is not an operation supported by any standards, but
		1836	happens to work on GNU/Linux and some newer BSD systems.
		1837
		1838	The only reasonable use for this function is to call it after forking, if
		1839	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1840	the process will result in undefined behaviour. Calling it at any time
		1841	will also result in any undefined (by POSIX) behaviour.
		1842
		1843	=back
1289		1844
1290	=head2 MEMORY USAGE	1845	=head2 MEMORY USAGE
1291		1846
1292	Per-request usage:	1847	Per-request usage:
1293		1848
…		…
1295	bytes of memory. In addition, stat requests need a stat buffer (possibly	1850	bytes of memory. In addition, stat requests need a stat buffer (possibly
1296	a few hundred bytes), readdir requires a result buffer and so on. Perl	1851	a few hundred bytes), readdir requires a result buffer and so on. Perl
1297	scalars and other data passed into aio requests will also be locked and	1852	scalars and other data passed into aio requests will also be locked and
1298	will consume memory till the request has entered the done state.	1853	will consume memory till the request has entered the done state.
1299		1854
1300	This is now awfully much, so queuing lots of requests is not usually a	1855	This is not awfully much, so queuing lots of requests is not usually a
1301	problem.	1856	problem.
1302		1857
1303	Per-thread usage:	1858	Per-thread usage:
1304		1859
1305	In the execution phase, some aio requests require more memory for	1860	In the execution phase, some aio requests require more memory for
…		…
1310		1865
1311	Known bugs will be fixed in the next release.	1866	Known bugs will be fixed in the next release.
1312		1867
1313	=head1 SEE ALSO	1868	=head1 SEE ALSO
1314		1869
1315	L<Coro::AIO>.	1870	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1871	more natural syntax.
1316		1872
1317	=head1 AUTHOR	1873	=head1 AUTHOR
1318		1874
1319	Marc Lehmann <schmorp@schmorp.de>	1875	Marc Lehmann <schmorp@schmorp.de>
1320	http://home.schmorp.de/	1876	http://home.schmorp.de/

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