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Revision 1.117 by root, Sat Oct 6 14:05:19 2007 UTC vs.
Revision 1.195 by root, Fri May 27 19:56:31 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.
…		…
185		163
186	package IO::AIO;	164	package IO::AIO;
187		165
188	use Carp ();	166	use Carp ();
189		167
190	no warnings;	168	use common::sense;
191	use strict 'vars';
192		169
193	use base 'Exporter';	170	use base 'Exporter';
194		171
195	BEGIN {	172	BEGIN {
196	our $VERSION = '2.51';	173	our $VERSION = '3.9';
197		174
198	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
199	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
200	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
		178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		179	aio_rename aio_link aio_move aio_copy aio_group
201	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
202	aio_chown aio_chmod aio_utime aio_truncate);	181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs);
		184
203	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
204	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
205	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle idle_timeout
206	nreqs nready npending nthreads	188	nreqs nready npending nthreads
207	max_poll_time max_poll_reqs);	189	max_poll_time max_poll_reqs
		190	sendfile fadvise madvise
		191	mmap munmap munlock munlockall);
		192
		193	push @AIO_REQ, qw(aio_busy); # not exported
208		194
209	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
210		196
211	require XSLoader;	197	require XSLoader;
212	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
213	}	199	}
214		200
215	=head1 FUNCTIONS	201	=head1 FUNCTIONS
		202
		203	=head2 QUICK OVERVIEW
		204
		205	This section simply lists the prototypes of the most important functions
		206	for quick reference. See the following sections for function-by-function
		207	documentation.
		208
		209	aio_open $pathname, $flags, $mode, $callback->($fh)
		210	aio_close $fh, $callback->($status)
		211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		214	aio_readahead $fh,$offset,$length, $callback->($retval)
		215	aio_stat $fh_or_path, $callback->($status)
		216	aio_lstat $fh, $callback->($status)
		217	aio_statvfs $fh_or_path, $callback->($statvfs)
		218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		220	aio_truncate $fh_or_path, $offset, $callback->($status)
		221	aio_chmod $fh_or_path, $mode, $callback->($status)
		222	aio_unlink $pathname, $callback->($status)
		223	aio_mknod $path, $mode, $dev, $callback->($status)
		224	aio_link $srcpath, $dstpath, $callback->($status)
		225	aio_symlink $srcpath, $dstpath, $callback->($status)
		226	aio_readlink $path, $callback->($link)
		227	aio_rename $srcpath, $dstpath, $callback->($status)
		228	aio_mkdir $pathname, $mode, $callback->($status)
		229	aio_rmdir $pathname, $callback->($status)
		230	aio_readdir $pathname, $callback->($entries)
		231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		234	aio_load $path, $data, $callback->($status)
		235	aio_copy $srcpath, $dstpath, $callback->($status)
		236	aio_move $srcpath, $dstpath, $callback->($status)
		237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		238	aio_rmtree $path, $callback->($status)
		239	aio_sync $callback->($status)
		240	aio_fsync $fh, $callback->($status)
		241	aio_fdatasync $fh, $callback->($status)
		242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		243	aio_pathsync $path, $callback->($status)
		244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		247	aio_mlockall $flags, $callback->($status)
		248	aio_group $callback->(...)
		249	aio_nop $callback->()
		250
		251	$prev_pri = aioreq_pri [$pri]
		252	aioreq_nice $pri_adjust
		253
		254	IO::AIO::poll_wait
		255	IO::AIO::poll_cb
		256	IO::AIO::poll
		257	IO::AIO::flush
		258	IO::AIO::max_poll_reqs $nreqs
		259	IO::AIO::max_poll_time $seconds
		260	IO::AIO::min_parallel $nthreads
		261	IO::AIO::max_parallel $nthreads
		262	IO::AIO::max_idle $nthreads
		263	IO::AIO::idle_timeout $seconds
		264	IO::AIO::max_outstanding $maxreqs
		265	IO::AIO::nreqs
		266	IO::AIO::nready
		267	IO::AIO::npending
		268
		269	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		270	IO::AIO::fadvise $fh, $offset, $len, $advice
		271	IO::AIO::madvise $scalar, $offset, $length, $advice
		272	IO::AIO::mprotect $scalar, $offset, $length, $protect
		273	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		274	IO::AIO::munlockall
216		275
217	=head2 AIO REQUEST FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
218		277
219	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
220	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
221	and they all accept an additional (and optional) C<$callback> argument	280	and they all accept an additional (and optional) C<$callback> argument
222	which must be a code reference. This code reference will get called with	281	which must be a code reference. This code reference will get called with
223	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	282	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
224	perl, which usually delivers "false") as it's sole argument when the given	283	perl, which usually delivers "false") as its sole argument after the given
225	syscall has been executed asynchronously.	284	syscall has been executed asynchronously.
226		285
227	All functions expecting a filehandle keep a copy of the filehandle	286	All functions expecting a filehandle keep a copy of the filehandle
228	internally until the request has finished.	287	internally until the request has finished.
229		288
…		…
243	your pathnames to the locale (or other) encoding in effect in the user	302	your pathnames to the locale (or other) encoding in effect in the user
244	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	303	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
245	use something else to ensure your scalar has the correct contents.	304	use something else to ensure your scalar has the correct contents.
246		305
247	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
248	handles correctly wether it is set or not.	307	handles correctly whether it is set or not.
249		308
250	=over 4	309	=over 4
251		310
252	=item $prev_pri = aioreq_pri [$pri]	311	=item $prev_pri = aioreq_pri [$pri]
253		312
…		…
300	by the umask in effect then the request is being executed, so better never	359	by the umask in effect then the request is being executed, so better never
301	change the umask.	360	change the umask.
302		361
303	Example:	362	Example:
304		363
305	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
306	if ($_[0]) {	365	if ($_[0]) {
307	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
308	...	367	...
309	} else {	368	} else {
310	die "open failed: $!\n";	369	die "open failed: $!\n";
311	}	370	}
312	};	371	};
313		372
		373	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		374	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		375	following POSIX and non-POSIX constants are available (missing ones on
		376	your system are, as usual, C<0>):
		377
		378	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		379	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		380	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		381
314		382
315	=item aio_close $fh, $callback->($status)	383	=item aio_close $fh, $callback->($status)
316		384
317	Asynchronously close a file and call the callback with the result	385	Asynchronously close a file and call the callback with the result
318	code.	386	code.
319		387
320	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on	388	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
321	closing the file descriptor associated with the filehandle itself. Here is	389	closing the file descriptor associated with the filehandle itself.
322	what aio_close will try:
323		390
324	1. dup()licate the fd	391	Therefore, C<aio_close> will not close the filehandle - instead it will
325	2. asynchronously close() the duplicated fd	392	use dup2 to overwrite the file descriptor with the write-end of a pipe
326	3. dup()licate the fd once more	393	(the pipe fd will be created on demand and will be cached).
327	4. let perl close() the filehandle
328	5. asynchronously close the duplicated fd
329		394
330	The idea is that the first close() flushes stuff to disk that closing an	395	Or in other words: the file descriptor will be closed, but it will not be
331	fd will flush, so when perl closes the fd, nothing much will need to be	396	free for reuse until the perl filehandle is closed.
332	flushed. The second async. close() will then flush stuff to disk that
333	closing the last fd to the file will flush.
334
335	Just FYI, SuSv3 has this to say on close:
336
337	All outstanding record locks owned by the process on the file
338	associated with the file descriptor shall be removed.
339
340	If fildes refers to a socket, close() shall cause the socket to be
341	destroyed. ... close() shall block for up to the current linger
342	interval until all data is transmitted.
343	[this actually sounds like a specification bug, but who knows]
344
345	And at least Linux additionally actually flushes stuff on every close,
346	even when the file itself is still open.
347
348	Sounds enourmously inefficient and complicated? Yes... please show me how
349	to nuke perl's fd out of existence...
350		397
351	=cut	398	=cut
352		399
353	sub aio_close($;$) {
354	aio_block {
355	my ($fh, $cb) = @_;
356
357	my $pri = aioreq_pri;
358	my $grp = aio_group $cb;
359
360	my $fd = fileno $fh;
361
362	defined $fd or Carp::croak "aio_close called with fd-less filehandle";
363
364	# if the dups fail we will simply get EBADF
365	my $fd2 = _dup $fd;
366	aioreq_pri $pri;
367	add $grp _aio_close $fd2, sub {
368	my $fd2 = _dup $fd;
369	close $fh;
370	aioreq_pri $pri;
371	add $grp _aio_close $fd2, sub {
372	$grp->result ($_[0]);
373	};
374	};
375
376	$grp
377	}
378	}
379
380
381	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	400	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
382		401
383	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	402	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
384		403
385	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>	404	Reads or writes C<$length> bytes from or to the specified C<$fh> and
386	into the scalar given by C<$data> and offset C<$dataoffset> and calls the	405	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
387	callback without the actual number of bytes read (or -1 on error, just	406	and calls the callback without the actual number of bytes read (or -1 on
388	like the syscall).	407	error, just like the syscall).
		408
		409	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		410	offset plus the actual number of bytes read.
389		411
390	If C<$offset> is undefined, then the current file descriptor offset will	412	If C<$offset> is undefined, then the current file descriptor offset will
391	be used (and updated), otherwise the file descriptor offset will not be	413	be used (and updated), otherwise the file descriptor offset will not be
392	changed by these calls.	414	changed by these calls.
393		415
394	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.	416	If C<$length> is undefined in C<aio_write>, use the remaining length of
		417	C<$data>.
395		418
396	If C<$dataoffset> is less than zero, it will be counted from the end of	419	If C<$dataoffset> is less than zero, it will be counted from the end of
397	C<$data>.	420	C<$data>.
398		421
399	The C<$data> scalar I<MUST NOT> be modified in any way while the request	422	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
415	reading at byte offset C<$in_offset>, and starts writing at the current	438	reading at byte offset C<$in_offset>, and starts writing at the current
416	file offset of C<$out_fh>. Because of that, it is not safe to issue more	439	file offset of C<$out_fh>. Because of that, it is not safe to issue more
417	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	440	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
418	other.	441	other.
419		442
		443	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		444	are written, and there is no way to find out how many bytes have been read
		445	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
		446	bytes written to C<$out_fh>. Only if the result value equals C<$length>
		447	one can assume that C<$length> bytes have been read.
		448
		449	Unlike with other C<aio_> functions, it makes a lot of sense to use
		450	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		451	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		452	the socket I/O will be non-blocking. Note, however, that you can run into
		453	a trap where C<aio_sendfile> reads some data with readahead, then fails
		454	to write all data, and when the socket is ready the next time, the data
		455	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		456	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		457	much better.
		458
420	This call tries to make use of a native C<sendfile> syscall to provide	459	This call tries to make use of a native C<sendfile> syscall to provide
421	zero-copy operation. For this to work, C<$out_fh> should refer to a	460	zero-copy operation. For this to work, C<$out_fh> should refer to a
422	socket, and C<$in_fh> should refer to mmap'able file.	461	socket, and C<$in_fh> should refer to an mmap'able file.
423		462
424	If the native sendfile call fails or is not implemented, it will be	463	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		464	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
425	emulated, so you can call C<aio_sendfile> on any type of filehandle	465	it will be emulated, so you can call C<aio_sendfile> on any type of
426	regardless of the limitations of the operating system.	466	filehandle regardless of the limitations of the operating system.
427
428	Please note, however, that C<aio_sendfile> can read more bytes from
429	C<$in_fh> than are written, and there is no way to find out how many
430	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
431	provides the number of bytes written to C<$out_fh>. Only if the result
432	value equals C<$length> one can assume that C<$length> bytes have been
433	read.
434		467
435		468
436	=item aio_readahead $fh,$offset,$length, $callback->($retval)	469	=item aio_readahead $fh,$offset,$length, $callback->($retval)
437		470
438	C<aio_readahead> populates the page cache with data from a file so that	471	C<aio_readahead> populates the page cache with data from a file so that
…		…
461		494
462	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	495	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
463	error when stat'ing a large file, the results will be silently truncated	496	error when stat'ing a large file, the results will be silently truncated
464	unless perl itself is compiled with large file support.	497	unless perl itself is compiled with large file support.
465		498
		499	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		500	following constants and functions (if not implemented, the constants will
		501	be C<0> and the functions will either C<croak> or fall back on traditional
		502	behaviour).
		503
		504	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		505	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		506	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		507
466	Example: Print the length of F</etc/passwd>:	508	Example: Print the length of F</etc/passwd>:
467		509
468	aio_stat "/etc/passwd", sub {	510	aio_stat "/etc/passwd", sub {
469	$_[0] and die "stat failed: $!";	511	$_[0] and die "stat failed: $!";
470	print "size is ", -s _, "\n";	512	print "size is ", -s _, "\n";
471	};	513	};
472		514
473		515
		516	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		517
		518	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		519	whether a file handle or path was passed.
		520
		521	On success, the callback is passed a hash reference with the following
		522	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		523	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		524	is passed.
		525
		526	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		527	C<ST_NOSUID>.
		528
		529	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		530	their correct value when available, or to C<0> on systems that do
		531	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		532	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		533	C<ST_NODIRATIME> and C<ST_RELATIME>.
		534
		535	Example: stat C</wd> and dump out the data if successful.
		536
		537	aio_statvfs "/wd", sub {
		538	my $f = $_[0]
		539	or die "statvfs: $!";
		540
		541	use Data::Dumper;
		542	say Dumper $f;
		543	};
		544
		545	# result:
		546	{
		547	bsize => 1024,
		548	bfree => 4333064312,
		549	blocks => 10253828096,
		550	files => 2050765568,
		551	flag => 4096,
		552	favail => 2042092649,
		553	bavail => 4333064312,
		554	ffree => 2042092649,
		555	namemax => 255,
		556	frsize => 1024,
		557	fsid => 1810
		558	}
		559
		560
474	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
475		562
476	Works like perl's C<utime> function (including the special case of $atime	563	Works like perl's C<utime> function (including the special case of $atime
477	and $mtime being undef). Fractional times are supported if the underlying	564	and $mtime being undef). Fractional times are supported if the underlying
478	syscalls support them.	565	syscalls support them.
…		…
526		613
527	The only (POSIX-) portable way of calling this function is:	614	The only (POSIX-) portable way of calling this function is:
528		615
529	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	616	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
530		617
		618	See C<aio_stat> for info about some potentially helpful extra constants
		619	and functions.
531		620
532	=item aio_link $srcpath, $dstpath, $callback->($status)	621	=item aio_link $srcpath, $dstpath, $callback->($status)
533		622
534	Asynchronously create a new link to the existing object at C<$srcpath> at	623	Asynchronously create a new link to the existing object at C<$srcpath> at
535	the path C<$dstpath> and call the callback with the result code.	624	the path C<$dstpath> and call the callback with the result code.
…		…
571		660
572	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	661	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
573	directory (i.e. opendir + readdir + closedir). The entries will not be	662	directory (i.e. opendir + readdir + closedir). The entries will not be
574	sorted, and will B<NOT> include the C<.> and C<..> entries.	663	sorted, and will B<NOT> include the C<.> and C<..> entries.
575		664
576	The callback a single argument which is either C<undef> or an array-ref	665	The callback is passed a single argument which is either C<undef> or an
577	with the filenames.	666	array-ref with the filenames.
		667
		668
		669	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		670
		671	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		672	behaviour and output format. In case of an error, C<$entries> will be
		673	C<undef>.
		674
		675	The flags are a combination of the following constants, ORed together (the
		676	flags will also be passed to the callback, possibly modified):
		677
		678	=over 4
		679
		680	=item IO::AIO::READDIR_DENTS
		681
		682	When this flag is off, then the callback gets an arrayref consisting of
		683	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		684	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		685	entry in more detail.
		686
		687	C<$name> is the name of the entry.
		688
		689	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		690
		691	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		692	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		693	C<IO::AIO::DT_WHT>.
		694
		695	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		696	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		697	scalars are read-only: you can not modify them.
		698
		699	C<$inode> is the inode number (which might not be exact on systems with 64
		700	bit inode numbers and 32 bit perls). This field has unspecified content on
		701	systems that do not deliver the inode information.
		702
		703	=item IO::AIO::READDIR_DIRS_FIRST
		704
		705	When this flag is set, then the names will be returned in an order where
		706	likely directories come first, in optimal stat order. This is useful when
		707	you need to quickly find directories, or you want to find all directories
		708	while avoiding to stat() each entry.
		709
		710	If the system returns type information in readdir, then this is used
		711	to find directories directly. Otherwise, likely directories are names
		712	beginning with ".", or otherwise names with no dots, of which names with
		713	short names are tried first.
		714
		715	=item IO::AIO::READDIR_STAT_ORDER
		716
		717	When this flag is set, then the names will be returned in an order
		718	suitable for stat()'ing each one. That is, when you plan to stat()
		719	all files in the given directory, then the returned order will likely
		720	be fastest.
		721
		722	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		723	the likely dirs come first, resulting in a less optimal stat order.
		724
		725	=item IO::AIO::READDIR_FOUND_UNKNOWN
		726
		727	This flag should not be set when calling C<aio_readdirx>. Instead, it
		728	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		729	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		730	C<$type>'s are known, which can be used to speed up some algorithms.
		731
		732	=back
578		733
579		734
580	=item aio_load $path, $data, $callback->($status)	735	=item aio_load $path, $data, $callback->($status)
581		736
582	This is a composite request that tries to fully load the given file into	737	This is a composite request that tries to fully load the given file into
583	memory. Status is the same as with aio_read.	738	memory. Status is the same as with aio_read.
584		739
585	=cut	740	=cut
586		741
587	sub aio_load($$;$) {	742	sub aio_load($$;$) {
588	aio_block {
589	my ($path, undef, $cb) = @_;	743	my ($path, undef, $cb) = @_;
590	my $data = \$_[1];	744	my $data = \$_[1];
591		745
592	my $pri = aioreq_pri;	746	my $pri = aioreq_pri;
593	my $grp = aio_group $cb;	747	my $grp = aio_group $cb;
		748
		749	aioreq_pri $pri;
		750	add $grp aio_open $path, O_RDONLY, 0, sub {
		751	my $fh = shift
		752	or return $grp->result (-1);
594		753
595	aioreq_pri $pri;	754	aioreq_pri $pri;
596	add $grp aio_open $path, O_RDONLY, 0, sub {
597	my $fh = shift
598	or return $grp->result (-1);
599
600	aioreq_pri $pri;
601	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	755	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
602	$grp->result ($_[0]);	756	$grp->result ($_[0]);
603	};
604	};	757	};
605
606	$grp
607	}	758	};
		759
		760	$grp
608	}	761	}
609		762
610	=item aio_copy $srcpath, $dstpath, $callback->($status)	763	=item aio_copy $srcpath, $dstpath, $callback->($status)
611		764
612	Try to copy the I<file> (directories not supported as either source or	765	Try to copy the I<file> (directories not supported as either source or
613	destination) from C<$srcpath> to C<$dstpath> and call the callback with	766	destination) from C<$srcpath> to C<$dstpath> and call the callback with
614	the C<0> (error) or C<-1> ok.	767	a status of C<0> (ok) or C<-1> (error, see C<$!>).
615		768
616	This is a composite request that it creates the destination file with	769	This is a composite request that creates the destination file with
617	mode 0200 and copies the contents of the source file into it using	770	mode 0200 and copies the contents of the source file into it using
618	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	771	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
619	uid/gid, in that order.	772	uid/gid, in that order.
620		773
621	If an error occurs, the partial destination file will be unlinked, if	774	If an error occurs, the partial destination file will be unlinked, if
…		…
623	errors are being ignored.	776	errors are being ignored.
624		777
625	=cut	778	=cut
626		779
627	sub aio_copy($$;$) {	780	sub aio_copy($$;$) {
628	aio_block {
629	my ($src, $dst, $cb) = @_;	781	my ($src, $dst, $cb) = @_;
630		782
631	my $pri = aioreq_pri;	783	my $pri = aioreq_pri;
632	my $grp = aio_group $cb;	784	my $grp = aio_group $cb;
633		785
634	aioreq_pri $pri;	786	aioreq_pri $pri;
635	add $grp aio_open $src, O_RDONLY, 0, sub {	787	add $grp aio_open $src, O_RDONLY, 0, sub {
636	if (my $src_fh = $_[0]) {	788	if (my $src_fh = $_[0]) {
637	my @stat = stat $src_fh;	789	my @stat = stat $src_fh; # hmm, might block over nfs?
638		790
639	aioreq_pri $pri;	791	aioreq_pri $pri;
640	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	792	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
641	if (my $dst_fh = $_[0]) {	793	if (my $dst_fh = $_[0]) {
642	aioreq_pri $pri;	794	aioreq_pri $pri;
643	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	795	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
644	if ($_[0] == $stat[7]) {	796	if ($_[0] == $stat[7]) {
645	$grp->result (0);	797	$grp->result (0);
646	close $src_fh;	798	close $src_fh;
647		799
648	# those should not normally block. should. should.
649	utime $stat[8], $stat[9], $dst;
650	chmod $stat[2] & 07777, $dst_fh;
651	chown $stat[4], $stat[5], $dst_fh;
652	close $dst_fh;
653	} else {	800	my $ch = sub {
654	$grp->result (-1);
655	close $src_fh;
656	close $dst_fh;
657
658	aioreq $pri;	801	aioreq_pri $pri;
		802	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		803	aioreq_pri $pri;
		804	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		805	aioreq_pri $pri;
659	add $grp aio_unlink $dst;	806	add $grp aio_close $dst_fh;
		807	}
		808	};
660	}	809	};
		810
		811	aioreq_pri $pri;
		812	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		813	if ($_[0] < 0 && $! == ENOSYS) {
		814	aioreq_pri $pri;
		815	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		816	} else {
		817	$ch->();
		818	}
		819	};
		820	} else {
		821	$grp->result (-1);
		822	close $src_fh;
		823	close $dst_fh;
		824
		825	aioreq $pri;
		826	add $grp aio_unlink $dst;
661	};	827	}
662	} else {
663	$grp->result (-1);
664	}	828	};
		829	} else {
		830	$grp->result (-1);
665	},	831	}
666
667	} else {
668	$grp->result (-1);
669	}	832	},
		833
		834	} else {
		835	$grp->result (-1);
670	};	836	}
671
672	$grp
673	}	837	};
		838
		839	$grp
674	}	840	}
675		841
676	=item aio_move $srcpath, $dstpath, $callback->($status)	842	=item aio_move $srcpath, $dstpath, $callback->($status)
677		843
678	Try to move the I<file> (directories not supported as either source or	844	Try to move the I<file> (directories not supported as either source or
679	destination) from C<$srcpath> to C<$dstpath> and call the callback with	845	destination) from C<$srcpath> to C<$dstpath> and call the callback with
680	the C<0> (error) or C<-1> ok.	846	a status of C<0> (ok) or C<-1> (error, see C<$!>).
681		847
682	This is a composite request that tries to rename(2) the file first. If	848	This is a composite request that tries to rename(2) the file first; if
683	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	849	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
684	that is successful, unlinking the C<$srcpath>.	850	that is successful, unlinks the C<$srcpath>.
685		851
686	=cut	852	=cut
687		853
688	sub aio_move($$;$) {	854	sub aio_move($$;$) {
689	aio_block {
690	my ($src, $dst, $cb) = @_;	855	my ($src, $dst, $cb) = @_;
691		856
692	my $pri = aioreq_pri;	857	my $pri = aioreq_pri;
693	my $grp = aio_group $cb;	858	my $grp = aio_group $cb;
694		859
695	aioreq_pri $pri;	860	aioreq_pri $pri;
696	add $grp aio_rename $src, $dst, sub {	861	add $grp aio_rename $src, $dst, sub {
697	if ($_[0] && $! == EXDEV) {	862	if ($_[0] && $! == EXDEV) {
698	aioreq_pri $pri;	863	aioreq_pri $pri;
699	add $grp aio_copy $src, $dst, sub {	864	add $grp aio_copy $src, $dst, sub {
700	$grp->result ($_[0]);
701
702	if (!$_[0]) {
703	aioreq_pri $pri;
704	add $grp aio_unlink $src;
705	}
706	};
707	} else {
708	$grp->result ($_[0]);	865	$grp->result ($_[0]);
		866
		867	if (!$_[0]) {
		868	aioreq_pri $pri;
		869	add $grp aio_unlink $src;
		870	}
709	}	871	};
		872	} else {
		873	$grp->result ($_[0]);
710	};	874	}
711
712	$grp
713	}	875	};
		876
		877	$grp
714	}	878	}
715		879
716	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	880	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
717		881
718	Scans a directory (similar to C<aio_readdir>) but additionally tries to	882	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
738		902
739	Implementation notes.	903	Implementation notes.
740		904
741	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	905	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
742		906
		907	If readdir returns file type information, then this is used directly to
		908	find directories.
		909
743	After reading the directory, the modification time, size etc. of the	910	Otherwise, after reading the directory, the modification time, size etc.
744	directory before and after the readdir is checked, and if they match (and	911	of the directory before and after the readdir is checked, and if they
745	isn't the current time), the link count will be used to decide how many	912	match (and isn't the current time), the link count will be used to decide
746	entries are directories (if >= 2). Otherwise, no knowledge of the number	913	how many entries are directories (if >= 2). Otherwise, no knowledge of the
747	of subdirectories will be assumed.	914	number of subdirectories will be assumed.
748		915
749	Then entries will be sorted into likely directories (everything without	916	Then entries will be sorted into likely directories a non-initial dot
750	a non-initial dot currently) and likely non-directories (everything	917	currently) and likely non-directories (see C<aio_readdirx>). Then every
751	else). Then every entry plus an appended C</.> will be C<stat>'ed,	918	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
752	likely directories first. If that succeeds, it assumes that the entry	919	in order of their inode numbers. If that succeeds, it assumes that the
753	is a directory or a symlink to directory (which will be checked	920	entry is a directory or a symlink to directory (which will be checked
754	seperately). This is often faster than stat'ing the entry itself because	921	seperately). This is often faster than stat'ing the entry itself because
755	filesystems might detect the type of the entry without reading the inode	922	filesystems might detect the type of the entry without reading the inode
756	data (e.g. ext2fs filetype feature).	923	data (e.g. ext2fs filetype feature), even on systems that cannot return
		924	the filetype information on readdir.
757		925
758	If the known number of directories (link count - 2) has been reached, the	926	If the known number of directories (link count - 2) has been reached, the
759	rest of the entries is assumed to be non-directories.	927	rest of the entries is assumed to be non-directories.
760		928
761	This only works with certainty on POSIX (= UNIX) filesystems, which	929	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
766	directory counting heuristic.	934	directory counting heuristic.
767		935
768	=cut	936	=cut
769		937
770	sub aio_scandir($$;$) {	938	sub aio_scandir($$;$) {
771	aio_block {
772	my ($path, $maxreq, $cb) = @_;	939	my ($path, $maxreq, $cb) = @_;
773		940
774	my $pri = aioreq_pri;	941	my $pri = aioreq_pri;
775		942
776	my $grp = aio_group $cb;	943	my $grp = aio_group $cb;
777		944
778	$maxreq = 4 if $maxreq <= 0;	945	$maxreq = 4 if $maxreq <= 0;
779		946
780	# stat once	947	# stat once
		948	aioreq_pri $pri;
		949	add $grp aio_stat $path, sub {
		950	return $grp->result () if $_[0];
		951	my $now = time;
		952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		953
		954	# read the directory entries
781	aioreq_pri $pri;	955	aioreq_pri $pri;
782	add $grp aio_stat $path, sub {	956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		957	my $entries = shift
783	return $grp->result () if $_[0];	958	or return $grp->result ();
784	my $now = time;
785	my $hash1 = join ":", (stat _)[0,1,3,7,9];
786		959
787	# read the directory entries	960	# stat the dir another time
788	aioreq_pri $pri;	961	aioreq_pri $pri;
789	add $grp aio_readdir $path, sub {
790	my $entries = shift
791	or return $grp->result ();
792
793	# stat the dir another time
794	aioreq_pri $pri;
795	add $grp aio_stat $path, sub {	962	add $grp aio_stat $path, sub {
796	my $hash2 = join ":", (stat _)[0,1,3,7,9];	963	my $hash2 = join ":", (stat _)[0,1,3,7,9];
797		964
798	my $ndirs;	965	my $ndirs;
799		966
800	# take the slow route if anything looks fishy	967	# take the slow route if anything looks fishy
801	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
802	$ndirs = -1;	969	$ndirs = -1;
803	} else {	970	} else {
804	# if nlink == 2, we are finished	971	# if nlink == 2, we are finished
805	# on non-posix-fs's, we rely on nlink < 2	972	# for non-posix-fs's, we rely on nlink < 2
806	$ndirs = (stat _)[3] - 2	973	$ndirs = (stat _)[3] - 2
807	or return $grp->result ([], $entries);	974	or return $grp->result ([], $entries);
808	}	975	}
809		976
810	# sort into likely dirs and likely nondirs
811	# dirs == files without ".", short entries first
812	$entries = [map $_->[0],
813	sort { $b->[1] cmp $a->[1] }
814	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
815	@$entries];
816
817	my (@dirs, @nondirs);	977	my (@dirs, @nondirs);
818		978
819	my $statgrp = add $grp aio_group sub {	979	my $statgrp = add $grp aio_group sub {
820	$grp->result (\@dirs, \@nondirs);	980	$grp->result (\@dirs, \@nondirs);
821	};	981	};
822		982
823	limit $statgrp $maxreq;	983	limit $statgrp $maxreq;
824	feed $statgrp sub {	984	feed $statgrp sub {
825	return unless @$entries;	985	return unless @$entries;
826	my $entry = pop @$entries;	986	my $entry = shift @$entries;
827		987
828	aioreq_pri $pri;	988	aioreq_pri $pri;
829	add $statgrp aio_stat "$path/$entry/.", sub {	989	add $statgrp aio_stat "$path/$entry/.", sub {
830	if ($_[0] < 0) {	990	if ($_[0] < 0) {
831	push @nondirs, $entry;	991	push @nondirs, $entry;
832	} else {	992	} else {
833	# need to check for real directory	993	# need to check for real directory
834	aioreq_pri $pri;	994	aioreq_pri $pri;
835	add $statgrp aio_lstat "$path/$entry", sub {	995	add $statgrp aio_lstat "$path/$entry", sub {
836	if (-d _) {	996	if (-d _) {
837	push @dirs, $entry;	997	push @dirs, $entry;
838		998
839	unless (--$ndirs) {	999	unless (--$ndirs) {
840	push @nondirs, @$entries;	1000	push @nondirs, @$entries;
841	feed $statgrp;	1001	feed $statgrp;
842	}
843	} else {
844	push @nondirs, $entry;
845	}	1002	}
		1003	} else {
		1004	push @nondirs, $entry;
846	}	1005	}
847	}	1006	}
848	};	1007	}
849	};	1008	};
850	};	1009	};
851	};	1010	};
852	};	1011	};
853
854	$grp
855	}	1012	};
		1013
		1014	$grp
856	}	1015	}
857		1016
858	=item aio_rmtree $path, $callback->($status)	1017	=item aio_rmtree $path, $callback->($status)
859		1018
860	Delete a directory tree starting (and including) C<$path>, return the	1019	Delete a directory tree starting (and including) C<$path>, return the
…		…
864		1023
865	=cut	1024	=cut
866		1025
867	sub aio_rmtree;	1026	sub aio_rmtree;
868	sub aio_rmtree($;$) {	1027	sub aio_rmtree($;$) {
869	aio_block {
870	my ($path, $cb) = @_;	1028	my ($path, $cb) = @_;
871		1029
872	my $pri = aioreq_pri;	1030	my $pri = aioreq_pri;
873	my $grp = aio_group $cb;	1031	my $grp = aio_group $cb;
874		1032
875	aioreq_pri $pri;	1033	aioreq_pri $pri;
876	add $grp aio_scandir $path, 0, sub {	1034	add $grp aio_scandir $path, 0, sub {
877	my ($dirs, $nondirs) = @_;	1035	my ($dirs, $nondirs) = @_;
878		1036
879	my $dirgrp = aio_group sub {	1037	my $dirgrp = aio_group sub {
880	add $grp aio_rmdir $path, sub {	1038	add $grp aio_rmdir $path, sub {
881	$grp->result ($_[0]);	1039	$grp->result ($_[0]);
882	};
883	};	1040	};
884
885	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
886	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
887
888	add $grp $dirgrp;
889	};	1041	};
890		1042
891	$grp	1043	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1044	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1045
		1046	add $grp $dirgrp;
892	}	1047	};
		1048
		1049	$grp
893	}	1050	}
		1051
		1052	=item aio_sync $callback->($status)
		1053
		1054	Asynchronously call sync and call the callback when finished.
894		1055
895	=item aio_fsync $fh, $callback->($status)	1056	=item aio_fsync $fh, $callback->($status)
896		1057
897	Asynchronously call fsync on the given filehandle and call the callback	1058	Asynchronously call fsync on the given filehandle and call the callback
898	with the fsync result code.	1059	with the fsync result code.
…		…
902	Asynchronously call fdatasync on the given filehandle and call the	1063	Asynchronously call fdatasync on the given filehandle and call the
903	callback with the fdatasync result code.	1064	callback with the fdatasync result code.
904		1065
905	If this call isn't available because your OS lacks it or it couldn't be	1066	If this call isn't available because your OS lacks it or it couldn't be
906	detected, it will be emulated by calling C<fsync> instead.	1067	detected, it will be emulated by calling C<fsync> instead.
		1068
		1069	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1070
		1071	Sync the data portion of the file specified by C<$offset> and C<$length>
		1072	to disk (but NOT the metadata), by calling the Linux-specific
		1073	sync_file_range call. If sync_file_range is not available or it returns
		1074	ENOSYS, then fdatasync or fsync is being substituted.
		1075
		1076	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1077	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1078	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1079	manpage for details.
		1080
		1081	=item aio_pathsync $path, $callback->($status)
		1082
		1083	This request tries to open, fsync and close the given path. This is a
		1084	composite request intended to sync directories after directory operations
		1085	(E.g. rename). This might not work on all operating systems or have any
		1086	specific effect, but usually it makes sure that directory changes get
		1087	written to disc. It works for anything that can be opened for read-only,
		1088	not just directories.
		1089
		1090	Future versions of this function might fall back to other methods when
		1091	C<fsync> on the directory fails (such as calling C<sync>).
		1092
		1093	Passes C<0> when everything went ok, and C<-1> on error.
		1094
		1095	=cut
		1096
		1097	sub aio_pathsync($;$) {
		1098	my ($path, $cb) = @_;
		1099
		1100	my $pri = aioreq_pri;
		1101	my $grp = aio_group $cb;
		1102
		1103	aioreq_pri $pri;
		1104	add $grp aio_open $path, O_RDONLY, 0, sub {
		1105	my ($fh) = @_;
		1106	if ($fh) {
		1107	aioreq_pri $pri;
		1108	add $grp aio_fsync $fh, sub {
		1109	$grp->result ($_[0]);
		1110
		1111	aioreq_pri $pri;
		1112	add $grp aio_close $fh;
		1113	};
		1114	} else {
		1115	$grp->result (-1);
		1116	}
		1117	};
		1118
		1119	$grp
		1120	}
		1121
		1122	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1123
		1124	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1125	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1126	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1127	scalar must only be modified in-place while an aio operation is pending on
		1128	it).
		1129
		1130	It calls the C<msync> function of your OS, if available, with the memory
		1131	area starting at C<$offset> in the string and ending C<$length> bytes
		1132	later. If C<$length> is negative, counts from the end, and if C<$length>
		1133	is C<undef>, then it goes till the end of the string. The flags can be
		1134	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1135	C<IO::AIO::MS_SYNC>.
		1136
		1137	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1138
		1139	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1140	scalars.
		1141
		1142	It touches (reads or writes) all memory pages in the specified
		1143	range inside the scalar. All caveats and parameters are the same
		1144	as for C<aio_msync>, above, except for flags, which must be either
		1145	C<0> (which reads all pages and ensures they are instantiated) or
		1146	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1147	writing an octet from it, which dirties the page).
		1148
		1149	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1150
		1151	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1152	scalars.
		1153
		1154	It reads in all the pages of the underlying storage into memory (if any)
		1155	and locks them, so they are not getting swapped/paged out or removed.
		1156
		1157	If C<$length> is undefined, then the scalar will be locked till the end.
		1158
		1159	On systems that do not implement C<mlock>, this function returns C<-1>
		1160	and sets errno to C<ENOSYS>.
		1161
		1162	Note that the corresponding C<munlock> is synchronous and is
		1163	documented under L<MISCELLANEOUS FUNCTIONS>.
		1164
		1165	Example: open a file, mmap and mlock it - both will be undone when
		1166	C<$data> gets destroyed.
		1167
		1168	open my $fh, "<", $path or die "$path: $!";
		1169	my $data;
		1170	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1171	aio_mlock $data; # mlock in background
		1172
		1173	=item aio_mlockall $flags, $callback->($status)
		1174
		1175	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1176	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1177
		1178	On systems that do not implement C<mlockall>, this function returns C<-1>
		1179	and sets errno to C<ENOSYS>.
		1180
		1181	Note that the corresponding C<munlockall> is synchronous and is
		1182	documented under L<MISCELLANEOUS FUNCTIONS>.
		1183
		1184	Example: asynchronously lock all current and future pages into memory.
		1185
		1186	aio_mlockall IO::AIO::MCL_FUTURE;
907		1187
908	=item aio_group $callback->(...)	1188	=item aio_group $callback->(...)
909		1189
910	This is a very special aio request: Instead of doing something, it is a	1190	This is a very special aio request: Instead of doing something, it is a
911	container for other aio requests, which is useful if you want to bundle	1191	container for other aio requests, which is useful if you want to bundle
…		…
961	=item cancel $req	1241	=item cancel $req
962		1242
963	Cancels the request, if possible. Has the effect of skipping execution	1243	Cancels the request, if possible. Has the effect of skipping execution
964	when entering the B<execute> state and skipping calling the callback when	1244	when entering the B<execute> state and skipping calling the callback when
965	entering the the B<result> state, but will leave the request otherwise	1245	entering the the B<result> state, but will leave the request otherwise
966	untouched. That means that requests that currently execute will not be	1246	untouched (with the exception of readdir). That means that requests that
967	stopped and resources held by the request will not be freed prematurely.	1247	currently execute will not be stopped and resources held by the request
		1248	will not be freed prematurely.
968		1249
969	=item cb $req $callback->(...)	1250	=item cb $req $callback->(...)
970		1251
971	Replace (or simply set) the callback registered to the request.	1252	Replace (or simply set) the callback registered to the request.
972		1253
…		…
1023	Their lifetime, simplified, looks like this: when they are empty, they	1304	Their lifetime, simplified, looks like this: when they are empty, they
1024	will finish very quickly. If they contain only requests that are in the	1305	will finish very quickly. If they contain only requests that are in the
1025	C<done> state, they will also finish. Otherwise they will continue to	1306	C<done> state, they will also finish. Otherwise they will continue to
1026	exist.	1307	exist.
1027		1308
1028	That means after creating a group you have some time to add requests. And	1309	That means after creating a group you have some time to add requests
1029	in the callbacks of those requests, you can add further requests to the	1310	(precisely before the callback has been invoked, which is only done within
1030	group. And only when all those requests have finished will the the group	1311	the C<poll_cb>). And in the callbacks of those requests, you can add
1031	itself finish.	1312	further requests to the group. And only when all those requests have
		1313	finished will the the group itself finish.
1032		1314
1033	=over 4	1315	=over 4
1034		1316
1035	=item add $grp ...	1317	=item add $grp ...
1036		1318
…		…
1045	=item $grp->cancel_subs	1327	=item $grp->cancel_subs
1046		1328
1047	Cancel all subrequests and clears any feeder, but not the group request	1329	Cancel all subrequests and clears any feeder, but not the group request
1048	itself. Useful when you queued a lot of events but got a result early.	1330	itself. Useful when you queued a lot of events but got a result early.
1049		1331
		1332	The group request will finish normally (you cannot add requests to the
		1333	group).
		1334
1050	=item $grp->result (...)	1335	=item $grp->result (...)
1051		1336
1052	Set the result value(s) that will be passed to the group callback when all	1337	Set the result value(s) that will be passed to the group callback when all
1053	subrequests have finished and set thre groups errno to the current value	1338	subrequests have finished and set the groups errno to the current value
1054	of errno (just like calling C<errno> without an error number). By default,	1339	of errno (just like calling C<errno> without an error number). By default,
1055	no argument will be passed and errno is zero.	1340	no argument will be passed and errno is zero.
1056		1341
1057	=item $grp->errno ([$errno])	1342	=item $grp->errno ([$errno])
1058		1343
…		…
1069	=item feed $grp $callback->($grp)	1354	=item feed $grp $callback->($grp)
1070		1355
1071	Sets a feeder/generator on this group: every group can have an attached	1356	Sets a feeder/generator on this group: every group can have an attached
1072	generator that generates requests if idle. The idea behind this is that,	1357	generator that generates requests if idle. The idea behind this is that,
1073	although you could just queue as many requests as you want in a group,	1358	although you could just queue as many requests as you want in a group,
1074	this might starve other requests for a potentially long time. For	1359	this might starve other requests for a potentially long time. For example,
1075	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1360	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1076	requests, delaying any later requests for a long time.	1361	delaying any later requests for a long time.
1077		1362
1078	To avoid this, and allow incremental generation of requests, you can	1363	To avoid this, and allow incremental generation of requests, you can
1079	instead a group and set a feeder on it that generates those requests. The	1364	instead a group and set a feeder on it that generates those requests. The
1080	feed callback will be called whenever there are few enough (see C<limit>,	1365	feed callback will be called whenever there are few enough (see C<limit>,
1081	below) requests active in the group itself and is expected to queue more	1366	below) requests active in the group itself and is expected to queue more
…		…
1085	not impose any limits).	1370	not impose any limits).
1086		1371
1087	If the feed does not queue more requests when called, it will be	1372	If the feed does not queue more requests when called, it will be
1088	automatically removed from the group.	1373	automatically removed from the group.
1089		1374
1090	If the feed limit is C<0>, it will be set to C<2> automatically.	1375	If the feed limit is C<0> when this method is called, it will be set to
		1376	C<2> automatically.
1091		1377
1092	Example:	1378	Example:
1093		1379
1094	# stat all files in @files, but only ever use four aio requests concurrently:	1380	# stat all files in @files, but only ever use four aio requests concurrently:
1095		1381
…		…
1107	Sets the feeder limit for the group: The feeder will be called whenever	1393	Sets the feeder limit for the group: The feeder will be called whenever
1108	the group contains less than this many requests.	1394	the group contains less than this many requests.
1109		1395
1110	Setting the limit to C<0> will pause the feeding process.	1396	Setting the limit to C<0> will pause the feeding process.
1111		1397
		1398	The default value for the limit is C<0>, but note that setting a feeder
		1399	automatically bumps it up to C<2>.
		1400
1112	=back	1401	=back
1113		1402
1114	=head2 SUPPORT FUNCTIONS	1403	=head2 SUPPORT FUNCTIONS
1115		1404
1116	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1405	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1118	=over 4	1407	=over 4
1119		1408
1120	=item $fileno = IO::AIO::poll_fileno	1409	=item $fileno = IO::AIO::poll_fileno
1121		1410
1122	Return the I<request result pipe file descriptor>. This filehandle must be	1411	Return the I<request result pipe file descriptor>. This filehandle must be
1123	polled for reading by some mechanism outside this module (e.g. Event or	1412	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1124	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1413	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1125	to call C<poll_cb> to check the results.	1414	you have to call C<poll_cb> to check the results.
1126		1415
1127	See C<poll_cb> for an example.	1416	See C<poll_cb> for an example.
1128		1417
1129	=item IO::AIO::poll_cb	1418	=item IO::AIO::poll_cb
1130		1419
1131	Process some outstanding events on the result pipe. You have to call this	1420	Process some outstanding events on the result pipe. You have to call
1132	regularly. Returns the number of events processed. Returns immediately	1421	this regularly. Returns C<0> if all events could be processed (or there
1133	when no events are outstanding. The amount of events processed depends on	1422	were no events to process), or C<-1> if it returned earlier for whatever
1134	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1423	reason. Returns immediately when no events are outstanding. The amount of
		1424	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1425	C<IO::AIO::max_poll_time>.
1135		1426
1136	If not all requests were processed for whatever reason, the filehandle	1427	If not all requests were processed for whatever reason, the filehandle
1137	will still be ready when C<poll_cb> returns.	1428	will still be ready when C<poll_cb> returns, so normally you don't have to
		1429	do anything special to have it called later.
		1430
		1431	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1432	ready, it can be beneficial to call this function from loops which submit
		1433	a lot of requests, to make sure the results get processed when they become
		1434	available and not just when the loop is finished and the event loop takes
		1435	over again. This function returns very fast when there are no outstanding
		1436	requests.
1138		1437
1139	Example: Install an Event watcher that automatically calls	1438	Example: Install an Event watcher that automatically calls
1140	IO::AIO::poll_cb with high priority:	1439	IO::AIO::poll_cb with high priority (more examples can be found in the
		1440	SYNOPSIS section, at the top of this document):
1141		1441
1142	Event->io (fd => IO::AIO::poll_fileno,	1442	Event->io (fd => IO::AIO::poll_fileno,
1143	poll => 'r', async => 1,	1443	poll => 'r', async => 1,
1144	cb => \&IO::AIO::poll_cb);	1444	cb => \&IO::AIO::poll_cb);
		1445
		1446	=item IO::AIO::poll_wait
		1447
		1448	If there are any outstanding requests and none of them in the result
		1449	phase, wait till the result filehandle becomes ready for reading (simply
		1450	does a C<select> on the filehandle. This is useful if you want to
		1451	synchronously wait for some requests to finish).
		1452
		1453	See C<nreqs> for an example.
		1454
		1455	=item IO::AIO::poll
		1456
		1457	Waits until some requests have been handled.
		1458
		1459	Returns the number of requests processed, but is otherwise strictly
		1460	equivalent to:
		1461
		1462	IO::AIO::poll_wait, IO::AIO::poll_cb
		1463
		1464	=item IO::AIO::flush
		1465
		1466	Wait till all outstanding AIO requests have been handled.
		1467
		1468	Strictly equivalent to:
		1469
		1470	IO::AIO::poll_wait, IO::AIO::poll_cb
		1471	while IO::AIO::nreqs;
1145		1472
1146	=item IO::AIO::max_poll_reqs $nreqs	1473	=item IO::AIO::max_poll_reqs $nreqs
1147		1474
1148	=item IO::AIO::max_poll_time $seconds	1475	=item IO::AIO::max_poll_time $seconds
1149		1476
…		…
1174	# use a low priority so other tasks have priority	1501	# use a low priority so other tasks have priority
1175	Event->io (fd => IO::AIO::poll_fileno,	1502	Event->io (fd => IO::AIO::poll_fileno,
1176	poll => 'r', nice => 1,	1503	poll => 'r', nice => 1,
1177	cb => &IO::AIO::poll_cb);	1504	cb => &IO::AIO::poll_cb);
1178		1505
1179	=item IO::AIO::poll_wait
1180
1181	If there are any outstanding requests and none of them in the result
1182	phase, wait till the result filehandle becomes ready for reading (simply
1183	does a C<select> on the filehandle. This is useful if you want to
1184	synchronously wait for some requests to finish).
1185
1186	See C<nreqs> for an example.
1187
1188	=item IO::AIO::poll
1189
1190	Waits until some requests have been handled.
1191
1192	Returns the number of requests processed, but is otherwise strictly
1193	equivalent to:
1194
1195	IO::AIO::poll_wait, IO::AIO::poll_cb
1196
1197	=item IO::AIO::flush
1198
1199	Wait till all outstanding AIO requests have been handled.
1200
1201	Strictly equivalent to:
1202
1203	IO::AIO::poll_wait, IO::AIO::poll_cb
1204	while IO::AIO::nreqs;
1205
1206	=back	1506	=back
1207		1507
1208	=head3 CONTROLLING THE NUMBER OF THREADS	1508	=head3 CONTROLLING THE NUMBER OF THREADS
1209		1509
1210	=over	1510	=over
…		…
1243		1543
1244	Under normal circumstances you don't need to call this function.	1544	Under normal circumstances you don't need to call this function.
1245		1545
1246	=item IO::AIO::max_idle $nthreads	1546	=item IO::AIO::max_idle $nthreads
1247		1547
1248	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1548	Limit the number of threads (default: 4) that are allowed to idle
1249	threads that did not get a request to process within 10 seconds). That	1549	(i.e., threads that did not get a request to process within the idle
1250	means if a thread becomes idle while C<$nthreads> other threads are also	1550	timeout (default: 10 seconds). That means if a thread becomes idle while
1251	idle, it will free its resources and exit.	1551	C<$nthreads> other threads are also idle, it will free its resources and
		1552	exit.
1252		1553
1253	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1554	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1254	to allow for extremely high load situations, but want to free resources	1555	to allow for extremely high load situations, but want to free resources
1255	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1556	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1256		1557
1257	The default is probably ok in most situations, especially if thread	1558	The default is probably ok in most situations, especially if thread
1258	creation is fast. If thread creation is very slow on your system you might	1559	creation is fast. If thread creation is very slow on your system you might
1259	want to use larger values.	1560	want to use larger values.
1260		1561
		1562	=item IO::AIO::idle_timeout $seconds
		1563
		1564	Sets the minimum idle timeout (default 10) after which worker threads are
		1565	allowed to exit. SEe C<IO::AIO::max_idle>.
		1566
1261	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1567	=item IO::AIO::max_outstanding $maxreqs
		1568
		1569	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1570	you do queue up more than this number of requests, the next call to
		1571	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1572	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1573	longer exceeded.
		1574
		1575	In other words, this setting does not enforce a queue limit, but can be
		1576	used to make poll functions block if the limit is exceeded.
1262		1577
1263	This is a very bad function to use in interactive programs because it	1578	This is a very bad function to use in interactive programs because it
1264	blocks, and a bad way to reduce concurrency because it is inexact: Better	1579	blocks, and a bad way to reduce concurrency because it is inexact: Better
1265	use an C<aio_group> together with a feed callback.	1580	use an C<aio_group> together with a feed callback.
1266		1581
1267	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1582	It's main use is in scripts without an event loop - when you want to stat
1268	do queue up more than this number of requests, the next call to the	1583	a lot of files, you can write somehting like this:
1269	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1270	function will block until the limit is no longer exceeded.
1271		1584
1272	The default value is very large, so there is no practical limit on the	1585	IO::AIO::max_outstanding 32;
1273	number of outstanding requests.
1274		1586
1275	You can still queue as many requests as you want. Therefore,	1587	for my $path (...) {
1276	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1588	aio_stat $path , ...;
1277	as a stop gap to shield against fatal memory overflow (with large values).	1589	IO::AIO::poll_cb;
		1590	}
		1591
		1592	IO::AIO::flush;
		1593
		1594	The call to C<poll_cb> inside the loop will normally return instantly, but
		1595	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1596	some requests have been handled. This keeps the loop from pushing a large
		1597	number of C<aio_stat> requests onto the queue.
		1598
		1599	The default value for C<max_outstanding> is very large, so there is no
		1600	practical limit on the number of outstanding requests.
1278		1601
1279	=back	1602	=back
1280		1603
1281	=head3 STATISTICAL INFORMATION	1604	=head3 STATISTICAL INFORMATION
1282		1605
…		…
1302	Returns the number of requests currently in the pending state (executed,	1625	Returns the number of requests currently in the pending state (executed,
1303	but not yet processed by poll_cb).	1626	but not yet processed by poll_cb).
1304		1627
1305	=back	1628	=back
1306		1629
		1630	=head3 MISCELLANEOUS FUNCTIONS
		1631
		1632	IO::AIO implements some functions that might be useful, but are not
		1633	asynchronous.
		1634
		1635	=over 4
		1636
		1637	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1638
		1639	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1640	but is blocking (this makes most sense if you know the input data is
		1641	likely cached already and the output filehandle is set to non-blocking
		1642	operations).
		1643
		1644	Returns the number of bytes copied, or C<-1> on error.
		1645
		1646	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1647
		1648	Simply calls the C<posix_fadvise> function (see its
		1649	manpage for details). The following advice constants are
		1650	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1651	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1652	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1653
		1654	On systems that do not implement C<posix_fadvise>, this function returns
		1655	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1656
		1657	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1658
		1659	Simply calls the C<posix_madvise> function (see its
		1660	manpage for details). The following advice constants are
		1661	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1662	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1663
		1664	On systems that do not implement C<posix_madvise>, this function returns
		1665	ENOSYS, otherwise the return value of C<posix_madvise>.
		1666
		1667	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1668
		1669	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1670	$scalar (see its manpage for details). The following protect
		1671	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1672	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1673
		1674	On systems that do not implement C<mprotect>, this function returns
		1675	ENOSYS, otherwise the return value of C<mprotect>.
		1676
		1677	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1678
		1679	Memory-maps a file (or anonymous memory range) and attaches it to the
		1680	given C<$scalar>, which will act like a string scalar.
		1681
		1682	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1683	change the string length, and most read-only operations such as copying it
		1684	or searching it with regexes and so on.
		1685
		1686	Anything else is unsafe and will, at best, result in memory leaks.
		1687
		1688	The memory map associated with the C<$scalar> is automatically removed
		1689	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1690	C<IO::AIO::munmap> functions are called.
		1691
		1692	This calls the C<mmap>(2) function internally. See your system's manual
		1693	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1694
		1695	The C<$length> must be larger than zero and smaller than the actual
		1696	filesize.
		1697
		1698	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1699	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1700
		1701	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1702	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1703	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1704	(which is set to C<MAP_ANON> if your system only provides this
		1705	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1706	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1707	C<IO::AIO::MAP_NONBLOCK>
		1708
		1709	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1710
		1711	C<$offset> is the offset from the start of the file - it generally must be
		1712	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1713
		1714	Example:
		1715
		1716	use Digest::MD5;
		1717	use IO::AIO;
		1718
		1719	open my $fh, "<verybigfile"
		1720	or die "$!";
		1721
		1722	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1723	or die "verybigfile: $!";
		1724
		1725	my $fast_md5 = md5 $data;
		1726
		1727	=item IO::AIO::munmap $scalar
		1728
		1729	Removes a previous mmap and undefines the C<$scalar>.
		1730
		1731	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1732
		1733	Calls the C<munlock> function, undoing the effects of a previous
		1734	C<aio_mlock> call (see its description for details).
		1735
		1736	=item IO::AIO::munlockall
		1737
		1738	Calls the C<munlockall> function.
		1739
		1740	On systems that do not implement C<munlockall>, this function returns
		1741	ENOSYS, otherwise the return value of C<munlockall>.
		1742
		1743	=back
		1744
1307	=cut	1745	=cut
1308		1746
1309	min_parallel 8;	1747	min_parallel 8;
1310		1748
1311	END { flush }	1749	END { flush }
1312		1750
1313	1;	1751	1;
		1752
		1753	=head1 EVENT LOOP INTEGRATION
		1754
		1755	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1756	automatically into many event loops:
		1757
		1758	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1759	use AnyEvent::AIO;
		1760
		1761	You can also integrate IO::AIO manually into many event loops, here are
		1762	some examples of how to do this:
		1763
		1764	# EV integration
		1765	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1766
		1767	# Event integration
		1768	Event->io (fd => IO::AIO::poll_fileno,
		1769	poll => 'r',
		1770	cb => \&IO::AIO::poll_cb);
		1771
		1772	# Glib/Gtk2 integration
		1773	add_watch Glib::IO IO::AIO::poll_fileno,
		1774	in => sub { IO::AIO::poll_cb; 1 };
		1775
		1776	# Tk integration
		1777	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1778	readable => \&IO::AIO::poll_cb);
		1779
		1780	# Danga::Socket integration
		1781	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1782	\&IO::AIO::poll_cb);
1314		1783
1315	=head2 FORK BEHAVIOUR	1784	=head2 FORK BEHAVIOUR
1316		1785
1317	This module should do "the right thing" when the process using it forks:	1786	This module should do "the right thing" when the process using it forks:
1318		1787
…		…
1351		1820
1352	Known bugs will be fixed in the next release.	1821	Known bugs will be fixed in the next release.
1353		1822
1354	=head1 SEE ALSO	1823	=head1 SEE ALSO
1355		1824
1356	L<Coro::AIO>.	1825	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1826	more natural syntax.
1357		1827
1358	=head1 AUTHOR	1828	=head1 AUTHOR
1359		1829
1360	Marc Lehmann <schmorp@schmorp.de>	1830	Marc Lehmann <schmorp@schmorp.de>
1361	http://home.schmorp.de/	1831	http://home.schmorp.de/

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