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Revision 1.119 by root, Sun Dec 2 20:54:33 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 (EV, Event, Glib, Tk, urxvt, pureperl...)
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	# EV integration
36	my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
37
38	# Event integration
39	Event->io (fd => IO::AIO::poll_fileno,
40	poll => 'r',
41	cb => \&IO::AIO::poll_cb);
42
43	# Glib/Gtk2 integration
44	add_watch Glib::IO IO::AIO::poll_fileno,
45	in => sub { IO::AIO::poll_cb; 1 };
46
47	# Tk integration
48	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
49	readable => \&IO::AIO::poll_cb);
50
51	# Danga::Socket integration
52	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
53	\&IO::AIO::poll_cb);
54
55	=head1 DESCRIPTION	31	=head1 DESCRIPTION
56		32
57	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
58	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>).
59		36
60	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
61	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
62	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
63	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
67	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
68	concurrently.	45	concurrently.
69		46
70	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
71	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
72	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
73	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>
74	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.
75		52
76	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
77	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
78	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
…		…
88	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
89	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
90		67
91	=head2 EXAMPLE	68	=head2 EXAMPLE
92		69
93	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
94	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
95		72
96	use Fcntl;	73	use Fcntl;
97	use Event;	74	use EV;
98	use IO::AIO;	75	use IO::AIO;
99		76
100	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
101	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102	poll => 'r',
103	cb => \&IO::AIO::poll_cb);
104		79
105	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
106	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
107	my $fh = shift	82	my $fh = shift
108	or die "error while opening: $!";	83	or die "error while opening: $!";
109		84
110	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
111	my $size = -s $fh;	86	my $size = -s $fh;
…		…
120		95
121	# file contents now in $contents	96	# file contents now in $contents
122	print $contents;	97	print $contents;
123		98
124	# exit event loop and program	99	# exit event loop and program
125	Event::unloop;	100	EV::unloop;
126	};	101	};
127	};	102	};
128		103
129	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
130	# check for sockets etc. etc.	105	# check for sockets etc. etc.
131		106
132	# process events as long as there are some:	107	# process events as long as there are some:
133	Event::loop;	108	EV::loop;
134		109
135	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
136		111
137	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
138	directly visible to Perl.	113	directly visible to Perl.
…		…
188		163
189	package IO::AIO;	164	package IO::AIO;
190		165
191	use Carp ();	166	use Carp ();
192		167
193	no warnings;	168	use common::sense;
194	use strict 'vars';
195		169
196	use base 'Exporter';	170	use base 'Exporter';
197		171
198	BEGIN {	172	BEGIN {
199	our $VERSION = '2.6';	173	our $VERSION = '3.9';
200		174
201	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
202	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
203	aio_readlink aio_sync 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
204	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
205	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
206	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
207	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
208	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle idle_timeout
209	nreqs nready npending nthreads	188	nreqs nready npending nthreads
210	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
211		194
212	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
213		196
214	require XSLoader;	197	require XSLoader;
215	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
216	}	199	}
217		200
218	=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, $length = undef
		274	IO::AIO::munlockall
219		275
220	=head2 AIO REQUEST FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
221		277
222	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
223	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
224	and they all accept an additional (and optional) C<$callback> argument	280	and they all accept an additional (and optional) C<$callback> argument
225	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
226	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
227	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
228	syscall has been executed asynchronously.	284	syscall has been executed asynchronously.
229		285
230	All functions expecting a filehandle keep a copy of the filehandle	286	All functions expecting a filehandle keep a copy of the filehandle
231	internally until the request has finished.	287	internally until the request has finished.
232		288
…		…
246	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
247	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)
248	use something else to ensure your scalar has the correct contents.	304	use something else to ensure your scalar has the correct contents.
249		305
250	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
251	handles correctly wether it is set or not.	307	handles correctly whether it is set or not.
252		308
253	=over 4	309	=over 4
254		310
255	=item $prev_pri = aioreq_pri [$pri]	311	=item $prev_pri = aioreq_pri [$pri]
256		312
…		…
303	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
304	change the umask.	360	change the umask.
305		361
306	Example:	362	Example:
307		363
308	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
309	if ($_[0]) {	365	if ($_[0]) {
310	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
311	...	367	...
312	} else {	368	} else {
313	die "open failed: $!\n";	369	die "open failed: $!\n";
314	}	370	}
315	};	371	};
316		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
317		382
318	=item aio_close $fh, $callback->($status)	383	=item aio_close $fh, $callback->($status)
319		384
320	Asynchronously close a file and call the callback with the result	385	Asynchronously close a file and call the callback with the result
321	code.	386	code.
322		387
323	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
324	closing the file descriptor associated with the filehandle itself. Here is	389	closing the file descriptor associated with the filehandle itself.
325	what aio_close will try:
326		390
327	1. dup()licate the fd	391	Therefore, C<aio_close> will not close the filehandle - instead it will
328	2. asynchronously close() the duplicated fd	392	use dup2 to overwrite the file descriptor with the write-end of a pipe
329	3. dup()licate the fd once more	393	(the pipe fd will be created on demand and will be cached).
330	4. let perl close() the filehandle
331	5. asynchronously close the duplicated fd
332		394
333	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
334	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.
335	flushed. The second async. close() will then flush stuff to disk that
336	closing the last fd to the file will flush.
337
338	Just FYI, SuSv3 has this to say on close:
339
340	All outstanding record locks owned by the process on the file
341	associated with the file descriptor shall be removed.
342
343	If fildes refers to a socket, close() shall cause the socket to be
344	destroyed. ... close() shall block for up to the current linger
345	interval until all data is transmitted.
346	[this actually sounds like a specification bug, but who knows]
347
348	And at least Linux additionally actually flushes stuff on every close,
349	even when the file itself is still open.
350
351	Sounds enourmously inefficient and complicated? Yes... please show me how
352	to nuke perl's fd out of existence...
353		397
354	=cut	398	=cut
355		399
356	sub aio_close($;$) {
357	aio_block {
358	my ($fh, $cb) = @_;
359
360	my $pri = aioreq_pri;
361	my $grp = aio_group $cb;
362
363	my $fd = fileno $fh;
364
365	defined $fd or Carp::croak "aio_close called with fd-less filehandle";
366
367	# if the dups fail we will simply get EBADF
368	my $fd2 = _dup $fd;
369	aioreq_pri $pri;
370	add $grp _aio_close $fd2, sub {
371	my $fd2 = _dup $fd;
372	close $fh;
373	aioreq_pri $pri;
374	add $grp _aio_close $fd2, sub {
375	$grp->result ($_[0]);
376	};
377	};
378
379	$grp
380	}
381	}
382
383
384	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	400	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
385		401
386	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	402	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
387		403
388	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<$fh> and
389	into the scalar given by C<$data> and offset C<$dataoffset> and calls the	405	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
390	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
391	like the syscall).	407	error, just like the syscall).
		408
		409	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		410	offset plus the actual number of bytes read.
392		411
393	If C<$offset> is undefined, then the current file descriptor offset will	412	If C<$offset> is undefined, then the current file descriptor offset will
394	be used (and updated), otherwise the file descriptor offset will not be	413	be used (and updated), otherwise the file descriptor offset will not be
395	changed by these calls.	414	changed by these calls.
396		415
397	If C<$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<$data>.
398		418
399	If C<$dataoffset> is less than zero, it will be counted from the end of	419	If C<$dataoffset> is less than zero, it will be counted from the end of
400	C<$data>.	420	C<$data>.
401		421
402	The C<$data> scalar I<MUST NOT> be modified in any way while the request	422	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
418	reading at byte offset C<$in_offset>, and starts writing at the current	438	reading at byte offset C<$in_offset>, and starts writing at the current
419	file offset of C<$out_fh>. Because of that, it is not safe to issue more	439	file offset of C<$out_fh>. Because of that, it is not safe to issue more
420	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	440	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
421	other.	441	other.
422		442
		443	Please note that C<aio_sendfile> can read more bytes from C<$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
423	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
424	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
425	socket, and C<$in_fh> should refer to mmap'able file.	461	socket, and C<$in_fh> should refer to an mmap'able file.
426		462
427	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>,
428	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
429	regardless of the limitations of the operating system.	466	filehandle regardless of the limitations of the operating system.
430
431	Please note, however, that C<aio_sendfile> can read more bytes from
432	C<$in_fh> than are written, and there is no way to find out how many
433	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
434	provides the number of bytes written to C<$out_fh>. Only if the result
435	value equals C<$length> one can assume that C<$length> bytes have been
436	read.
437		467
438		468
439	=item aio_readahead $fh,$offset,$length, $callback->($retval)	469	=item aio_readahead $fh,$offset,$length, $callback->($retval)
440		470
441	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
…		…
464		494
465	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
466	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
467	unless perl itself is compiled with large file support.	497	unless perl itself is compiled with large file support.
468		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
469	Example: Print the length of F</etc/passwd>:	508	Example: Print the length of F</etc/passwd>:
470		509
471	aio_stat "/etc/passwd", sub {	510	aio_stat "/etc/passwd", sub {
472	$_[0] and die "stat failed: $!";	511	$_[0] and die "stat failed: $!";
473	print "size is ", -s _, "\n";	512	print "size is ", -s _, "\n";
474	};	513	};
475		514
476		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
477	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
478		562
479	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
480	and $mtime being undef). Fractional times are supported if the underlying	564	and $mtime being undef). Fractional times are supported if the underlying
481	syscalls support them.	565	syscalls support them.
…		…
529		613
530	The only (POSIX-) portable way of calling this function is:	614	The only (POSIX-) portable way of calling this function is:
531		615
532	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	616	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
533		617
		618	See C<aio_stat> for info about some potentially helpful extra constants
		619	and functions.
534		620
535	=item aio_link $srcpath, $dstpath, $callback->($status)	621	=item aio_link $srcpath, $dstpath, $callback->($status)
536		622
537	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
538	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.
…		…
574		660
575	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
576	directory (i.e. opendir + readdir + closedir). The entries will not be	662	directory (i.e. opendir + readdir + closedir). The entries will not be
577	sorted, and will B<NOT> include the C<.> and C<..> entries.	663	sorted, and will B<NOT> include the C<.> and C<..> entries.
578		664
579	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
580	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
581		733
582		734
583	=item aio_load $path, $data, $callback->($status)	735	=item aio_load $path, $data, $callback->($status)
584		736
585	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
586	memory. Status is the same as with aio_read.	738	memory. Status is the same as with aio_read.
587		739
588	=cut	740	=cut
589		741
590	sub aio_load($$;$) {	742	sub aio_load($$;$) {
591	aio_block {
592	my ($path, undef, $cb) = @_;	743	my ($path, undef, $cb) = @_;
593	my $data = \$_[1];	744	my $data = \$_[1];
594		745
595	my $pri = aioreq_pri;	746	my $pri = aioreq_pri;
596	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);
597		753
598	aioreq_pri $pri;	754	aioreq_pri $pri;
599	add $grp aio_open $path, O_RDONLY, 0, sub {
600	my $fh = shift
601	or return $grp->result (-1);
602
603	aioreq_pri $pri;
604	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	755	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
605	$grp->result ($_[0]);	756	$grp->result ($_[0]);
606	};
607	};	757	};
608
609	$grp
610	}	758	};
		759
		760	$grp
611	}	761	}
612		762
613	=item aio_copy $srcpath, $dstpath, $callback->($status)	763	=item aio_copy $srcpath, $dstpath, $callback->($status)
614		764
615	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
616	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
617	the C<0> (error) or C<-1> ok.	767	a status of C<0> (ok) or C<-1> (error, see C<$!>).
618		768
619	This is a composite request that it creates the destination file with	769	This is a composite request that creates the destination file with
620	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
621	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	771	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
622	uid/gid, in that order.	772	uid/gid, in that order.
623		773
624	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
…		…
626	errors are being ignored.	776	errors are being ignored.
627		777
628	=cut	778	=cut
629		779
630	sub aio_copy($$;$) {	780	sub aio_copy($$;$) {
631	aio_block {
632	my ($src, $dst, $cb) = @_;	781	my ($src, $dst, $cb) = @_;
633		782
634	my $pri = aioreq_pri;	783	my $pri = aioreq_pri;
635	my $grp = aio_group $cb;	784	my $grp = aio_group $cb;
636		785
637	aioreq_pri $pri;	786	aioreq_pri $pri;
638	add $grp aio_open $src, O_RDONLY, 0, sub {	787	add $grp aio_open $src, O_RDONLY, 0, sub {
639	if (my $src_fh = $_[0]) {	788	if (my $src_fh = $_[0]) {
640	my @stat = stat $src_fh;	789	my @stat = stat $src_fh; # hmm, might block over nfs?
641		790
642	aioreq_pri $pri;	791	aioreq_pri $pri;
643	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 {
644	if (my $dst_fh = $_[0]) {	793	if (my $dst_fh = $_[0]) {
645	aioreq_pri $pri;	794	aioreq_pri $pri;
646	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	795	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
647	if ($_[0] == $stat[7]) {	796	if ($_[0] == $stat[7]) {
648	$grp->result (0);	797	$grp->result (0);
649	close $src_fh;	798	close $src_fh;
650		799
651	# those should not normally block. should. should.
652	utime $stat[8], $stat[9], $dst;
653	chmod $stat[2] & 07777, $dst_fh;
654	chown $stat[4], $stat[5], $dst_fh;
655	close $dst_fh;
656	} else {	800	my $ch = sub {
657	$grp->result (-1);
658	close $src_fh;
659	close $dst_fh;
660
661	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;
662	add $grp aio_unlink $dst;	806	add $grp aio_close $dst_fh;
		807	}
		808	};
663	}	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;
664	};	827	}
665	} else {
666	$grp->result (-1);
667	}	828	};
		829	} else {
		830	$grp->result (-1);
668	},	831	}
669
670	} else {
671	$grp->result (-1);
672	}	832	},
		833
		834	} else {
		835	$grp->result (-1);
673	};	836	}
674
675	$grp
676	}	837	};
		838
		839	$grp
677	}	840	}
678		841
679	=item aio_move $srcpath, $dstpath, $callback->($status)	842	=item aio_move $srcpath, $dstpath, $callback->($status)
680		843
681	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
682	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
683	the C<0> (error) or C<-1> ok.	846	a status of C<0> (ok) or C<-1> (error, see C<$!>).
684		847
685	This is a composite request that tries to rename(2) the file first. If	848	This is a composite request that tries to rename(2) the file first; if
686	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	849	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
687	that is successful, unlinking the C<$srcpath>.	850	that is successful, unlinks the C<$srcpath>.
688		851
689	=cut	852	=cut
690		853
691	sub aio_move($$;$) {	854	sub aio_move($$;$) {
692	aio_block {
693	my ($src, $dst, $cb) = @_;	855	my ($src, $dst, $cb) = @_;
694		856
695	my $pri = aioreq_pri;	857	my $pri = aioreq_pri;
696	my $grp = aio_group $cb;	858	my $grp = aio_group $cb;
697		859
698	aioreq_pri $pri;	860	aioreq_pri $pri;
699	add $grp aio_rename $src, $dst, sub {	861	add $grp aio_rename $src, $dst, sub {
700	if ($_[0] && $! == EXDEV) {	862	if ($_[0] && $! == EXDEV) {
701	aioreq_pri $pri;	863	aioreq_pri $pri;
702	add $grp aio_copy $src, $dst, sub {	864	add $grp aio_copy $src, $dst, sub {
703	$grp->result ($_[0]);
704
705	if (!$_[0]) {
706	aioreq_pri $pri;
707	add $grp aio_unlink $src;
708	}
709	};
710	} else {
711	$grp->result ($_[0]);	865	$grp->result ($_[0]);
		866
		867	if (!$_[0]) {
		868	aioreq_pri $pri;
		869	add $grp aio_unlink $src;
		870	}
712	}	871	};
		872	} else {
		873	$grp->result ($_[0]);
713	};	874	}
714
715	$grp
716	}	875	};
		876
		877	$grp
717	}	878	}
718		879
719	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	880	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
720		881
721	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
…		…
741		902
742	Implementation notes.	903	Implementation notes.
743		904
744	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.
745		906
		907	If readdir returns file type information, then this is used directly to
		908	find directories.
		909
746	After reading the directory, the modification time, size etc. of the	910	Otherwise, after reading the directory, the modification time, size etc.
747	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
748	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
749	entries are directories (if >= 2). Otherwise, no knowledge of the number	913	how many entries are directories (if >= 2). Otherwise, no knowledge of the
750	of subdirectories will be assumed.	914	number of subdirectories will be assumed.
751		915
752	Then entries will be sorted into likely directories (everything without	916	Then entries will be sorted into likely directories a non-initial dot
753	a non-initial dot currently) and likely non-directories (everything	917	currently) and likely non-directories (see C<aio_readdirx>). Then every
754	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,
755	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
756	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
757	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
758	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
759	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.
760		925
761	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
762	rest of the entries is assumed to be non-directories.	927	rest of the entries is assumed to be non-directories.
763		928
764	This only works with certainty on POSIX (= UNIX) filesystems, which	929	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
769	directory counting heuristic.	934	directory counting heuristic.
770		935
771	=cut	936	=cut
772		937
773	sub aio_scandir($$;$) {	938	sub aio_scandir($$;$) {
774	aio_block {
775	my ($path, $maxreq, $cb) = @_;	939	my ($path, $maxreq, $cb) = @_;
776		940
777	my $pri = aioreq_pri;	941	my $pri = aioreq_pri;
778		942
779	my $grp = aio_group $cb;	943	my $grp = aio_group $cb;
780		944
781	$maxreq = 4 if $maxreq <= 0;	945	$maxreq = 4 if $maxreq <= 0;
782		946
783	# 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
784	aioreq_pri $pri;	955	aioreq_pri $pri;
785	add $grp aio_stat $path, sub {	956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		957	my $entries = shift
786	return $grp->result () if $_[0];	958	or return $grp->result ();
787	my $now = time;
788	my $hash1 = join ":", (stat _)[0,1,3,7,9];
789		959
790	# read the directory entries	960	# stat the dir another time
791	aioreq_pri $pri;	961	aioreq_pri $pri;
792	add $grp aio_readdir $path, sub {
793	my $entries = shift
794	or return $grp->result ();
795
796	# stat the dir another time
797	aioreq_pri $pri;
798	add $grp aio_stat $path, sub {	962	add $grp aio_stat $path, sub {
799	my $hash2 = join ":", (stat _)[0,1,3,7,9];	963	my $hash2 = join ":", (stat _)[0,1,3,7,9];
800		964
801	my $ndirs;	965	my $ndirs;
802		966
803	# take the slow route if anything looks fishy	967	# take the slow route if anything looks fishy
804	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
805	$ndirs = -1;	969	$ndirs = -1;
806	} else {	970	} else {
807	# if nlink == 2, we are finished	971	# if nlink == 2, we are finished
808	# on non-posix-fs's, we rely on nlink < 2	972	# for non-posix-fs's, we rely on nlink < 2
809	$ndirs = (stat _)[3] - 2	973	$ndirs = (stat _)[3] - 2
810	or return $grp->result ([], $entries);	974	or return $grp->result ([], $entries);
811	}	975	}
812		976
813	# sort into likely dirs and likely nondirs
814	# dirs == files without ".", short entries first
815	$entries = [map $_->[0],
816	sort { $b->[1] cmp $a->[1] }
817	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
818	@$entries];
819
820	my (@dirs, @nondirs);	977	my (@dirs, @nondirs);
821		978
822	my $statgrp = add $grp aio_group sub {	979	my $statgrp = add $grp aio_group sub {
823	$grp->result (\@dirs, \@nondirs);	980	$grp->result (\@dirs, \@nondirs);
824	};	981	};
825		982
826	limit $statgrp $maxreq;	983	limit $statgrp $maxreq;
827	feed $statgrp sub {	984	feed $statgrp sub {
828	return unless @$entries;	985	return unless @$entries;
829	my $entry = pop @$entries;	986	my $entry = shift @$entries;
830		987
831	aioreq_pri $pri;	988	aioreq_pri $pri;
832	add $statgrp aio_stat "$path/$entry/.", sub {	989	add $statgrp aio_stat "$path/$entry/.", sub {
833	if ($_[0] < 0) {	990	if ($_[0] < 0) {
834	push @nondirs, $entry;	991	push @nondirs, $entry;
835	} else {	992	} else {
836	# need to check for real directory	993	# need to check for real directory
837	aioreq_pri $pri;	994	aioreq_pri $pri;
838	add $statgrp aio_lstat "$path/$entry", sub {	995	add $statgrp aio_lstat "$path/$entry", sub {
839	if (-d _) {	996	if (-d _) {
840	push @dirs, $entry;	997	push @dirs, $entry;
841		998
842	unless (--$ndirs) {	999	unless (--$ndirs) {
843	push @nondirs, @$entries;	1000	push @nondirs, @$entries;
844	feed $statgrp;	1001	feed $statgrp;
845	}
846	} else {
847	push @nondirs, $entry;
848	}	1002	}
		1003	} else {
		1004	push @nondirs, $entry;
849	}	1005	}
850	}	1006	}
851	};	1007	}
852	};	1008	};
853	};	1009	};
854	};	1010	};
855	};	1011	};
856
857	$grp
858	}	1012	};
		1013
		1014	$grp
859	}	1015	}
860		1016
861	=item aio_rmtree $path, $callback->($status)	1017	=item aio_rmtree $path, $callback->($status)
862		1018
863	Delete a directory tree starting (and including) C<$path>, return the	1019	Delete a directory tree starting (and including) C<$path>, return the
…		…
867		1023
868	=cut	1024	=cut
869		1025
870	sub aio_rmtree;	1026	sub aio_rmtree;
871	sub aio_rmtree($;$) {	1027	sub aio_rmtree($;$) {
872	aio_block {
873	my ($path, $cb) = @_;	1028	my ($path, $cb) = @_;
874		1029
875	my $pri = aioreq_pri;	1030	my $pri = aioreq_pri;
876	my $grp = aio_group $cb;	1031	my $grp = aio_group $cb;
877		1032
878	aioreq_pri $pri;	1033	aioreq_pri $pri;
879	add $grp aio_scandir $path, 0, sub {	1034	add $grp aio_scandir $path, 0, sub {
880	my ($dirs, $nondirs) = @_;	1035	my ($dirs, $nondirs) = @_;
881		1036
882	my $dirgrp = aio_group sub {	1037	my $dirgrp = aio_group sub {
883	add $grp aio_rmdir $path, sub {	1038	add $grp aio_rmdir $path, sub {
884	$grp->result ($_[0]);	1039	$grp->result ($_[0]);
885	};
886	};	1040	};
887
888	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
889	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
890
891	add $grp $dirgrp;
892	};	1041	};
893		1042
894	$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;
895	}	1047	};
		1048
		1049	$grp
896	}	1050	}
897		1051
898	=item aio_sync $callback->($status)	1052	=item aio_sync $callback->($status)
899		1053
900	Asynchronously call sync and call the callback when finished.	1054	Asynchronously call sync and call the callback when finished.
…		…
909	Asynchronously call fdatasync on the given filehandle and call the	1063	Asynchronously call fdatasync on the given filehandle and call the
910	callback with the fdatasync result code.	1064	callback with the fdatasync result code.
911		1065
912	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
913	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;
914		1187
915	=item aio_group $callback->(...)	1188	=item aio_group $callback->(...)
916		1189
917	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
918	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
…		…
968	=item cancel $req	1241	=item cancel $req
969		1242
970	Cancels the request, if possible. Has the effect of skipping execution	1243	Cancels the request, if possible. Has the effect of skipping execution
971	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
972	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
973	untouched. That means that requests that currently execute will not be	1246	untouched (with the exception of readdir). That means that requests that
974	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.
975		1249
976	=item cb $req $callback->(...)	1250	=item cb $req $callback->(...)
977		1251
978	Replace (or simply set) the callback registered to the request.	1252	Replace (or simply set) the callback registered to the request.
979		1253
…		…
1030	Their lifetime, simplified, looks like this: when they are empty, they	1304	Their lifetime, simplified, looks like this: when they are empty, they
1031	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
1032	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
1033	exist.	1307	exist.
1034		1308
1035	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
1036	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
1037	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
1038	itself finish.	1312	further requests to the group. And only when all those requests have
		1313	finished will the the group itself finish.
1039		1314
1040	=over 4	1315	=over 4
1041		1316
1042	=item add $grp ...	1317	=item add $grp ...
1043		1318
…		…
1052	=item $grp->cancel_subs	1327	=item $grp->cancel_subs
1053		1328
1054	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
1055	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.
1056		1331
		1332	The group request will finish normally (you cannot add requests to the
		1333	group).
		1334
1057	=item $grp->result (...)	1335	=item $grp->result (...)
1058		1336
1059	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
1060	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
1061	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,
1062	no argument will be passed and errno is zero.	1340	no argument will be passed and errno is zero.
1063		1341
1064	=item $grp->errno ([$errno])	1342	=item $grp->errno ([$errno])
1065		1343
…		…
1076	=item feed $grp $callback->($grp)	1354	=item feed $grp $callback->($grp)
1077		1355
1078	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
1079	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,
1080	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,
1081	this might starve other requests for a potentially long time. For	1359	this might starve other requests for a potentially long time. For example,
1082	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,
1083	requests, delaying any later requests for a long time.	1361	delaying any later requests for a long time.
1084		1362
1085	To avoid this, and allow incremental generation of requests, you can	1363	To avoid this, and allow incremental generation of requests, you can
1086	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
1087	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>,
1088	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
…		…
1092	not impose any limits).	1370	not impose any limits).
1093		1371
1094	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
1095	automatically removed from the group.	1373	automatically removed from the group.
1096		1374
1097	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.
1098		1377
1099	Example:	1378	Example:
1100		1379
1101	# 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:
1102		1381
…		…
1114	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
1115	the group contains less than this many requests.	1394	the group contains less than this many requests.
1116		1395
1117	Setting the limit to C<0> will pause the feeding process.	1396	Setting the limit to C<0> will pause the feeding process.
1118		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
1119	=back	1401	=back
1120		1402
1121	=head2 SUPPORT FUNCTIONS	1403	=head2 SUPPORT FUNCTIONS
1122		1404
1123	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1405	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1125	=over 4	1407	=over 4
1126		1408
1127	=item $fileno = IO::AIO::poll_fileno	1409	=item $fileno = IO::AIO::poll_fileno
1128		1410
1129	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
1130	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,
1131	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
1132	to call C<poll_cb> to check the results.	1414	you have to call C<poll_cb> to check the results.
1133		1415
1134	See C<poll_cb> for an example.	1416	See C<poll_cb> for an example.
1135		1417
1136	=item IO::AIO::poll_cb	1418	=item IO::AIO::poll_cb
1137		1419
1138	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
1139	regularly. Returns the number of events processed. Returns immediately	1421	this regularly. Returns C<0> if all events could be processed (or there
1140	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
1141	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>.
1142		1426
1143	If not all requests were processed for whatever reason, the filehandle	1427	If not all requests were processed for whatever reason, the filehandle
1144	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.
1145		1437
1146	Example: Install an Event watcher that automatically calls	1438	Example: Install an Event watcher that automatically calls
1147	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):
1148		1441
1149	Event->io (fd => IO::AIO::poll_fileno,	1442	Event->io (fd => IO::AIO::poll_fileno,
1150	poll => 'r', async => 1,	1443	poll => 'r', async => 1,
1151	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;
1152		1472
1153	=item IO::AIO::max_poll_reqs $nreqs	1473	=item IO::AIO::max_poll_reqs $nreqs
1154		1474
1155	=item IO::AIO::max_poll_time $seconds	1475	=item IO::AIO::max_poll_time $seconds
1156		1476
…		…
1181	# use a low priority so other tasks have priority	1501	# use a low priority so other tasks have priority
1182	Event->io (fd => IO::AIO::poll_fileno,	1502	Event->io (fd => IO::AIO::poll_fileno,
1183	poll => 'r', nice => 1,	1503	poll => 'r', nice => 1,
1184	cb => &IO::AIO::poll_cb);	1504	cb => &IO::AIO::poll_cb);
1185		1505
1186	=item IO::AIO::poll_wait
1187
1188	If there are any outstanding requests and none of them in the result
1189	phase, wait till the result filehandle becomes ready for reading (simply
1190	does a C<select> on the filehandle. This is useful if you want to
1191	synchronously wait for some requests to finish).
1192
1193	See C<nreqs> for an example.
1194
1195	=item IO::AIO::poll
1196
1197	Waits until some requests have been handled.
1198
1199	Returns the number of requests processed, but is otherwise strictly
1200	equivalent to:
1201
1202	IO::AIO::poll_wait, IO::AIO::poll_cb
1203
1204	=item IO::AIO::flush
1205
1206	Wait till all outstanding AIO requests have been handled.
1207
1208	Strictly equivalent to:
1209
1210	IO::AIO::poll_wait, IO::AIO::poll_cb
1211	while IO::AIO::nreqs;
1212
1213	=back	1506	=back
1214		1507
1215	=head3 CONTROLLING THE NUMBER OF THREADS	1508	=head3 CONTROLLING THE NUMBER OF THREADS
1216		1509
1217	=over	1510	=over
…		…
1250		1543
1251	Under normal circumstances you don't need to call this function.	1544	Under normal circumstances you don't need to call this function.
1252		1545
1253	=item IO::AIO::max_idle $nthreads	1546	=item IO::AIO::max_idle $nthreads
1254		1547
1255	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1548	Limit the number of threads (default: 4) that are allowed to idle
1256	threads that did not get a request to process within 10 seconds). That	1549	(i.e., threads that did not get a request to process within the idle
1257	means if a thread becomes idle while C<$nthreads> other threads are also	1550	timeout (default: 10 seconds). That means if a thread becomes idle while
1258	idle, it will free its resources and exit.	1551	C<$nthreads> other threads are also idle, it will free its resources and
		1552	exit.
1259		1553
1260	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)
1261	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
1262	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1556	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1263		1557
1264	The default is probably ok in most situations, especially if thread	1558	The default is probably ok in most situations, especially if thread
1265	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
1266	want to use larger values.	1560	want to use larger values.
1267		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
1268	=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.
1269		1577
1270	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
1271	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
1272	use an C<aio_group> together with a feed callback.	1580	use an C<aio_group> together with a feed callback.
1273		1581
1274	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
1275	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:
1276	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1277	function will block until the limit is no longer exceeded.
1278		1584
1279	The default value is very large, so there is no practical limit on the	1585	IO::AIO::max_outstanding 32;
1280	number of outstanding requests.
1281		1586
1282	You can still queue as many requests as you want. Therefore,	1587	for my $path (...) {
1283	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1588	aio_stat $path , ...;
1284	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.
1285		1601
1286	=back	1602	=back
1287		1603
1288	=head3 STATISTICAL INFORMATION	1604	=head3 STATISTICAL INFORMATION
1289		1605
…		…
1309	Returns the number of requests currently in the pending state (executed,	1625	Returns the number of requests currently in the pending state (executed,
1310	but not yet processed by poll_cb).	1626	but not yet processed by poll_cb).
1311		1627
1312	=back	1628	=back
1313		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
1314	=cut	1745	=cut
1315		1746
1316	min_parallel 8;	1747	min_parallel 8;
1317		1748
1318	END { flush }	1749	END { flush }
1319		1750
1320	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);
1321		1783
1322	=head2 FORK BEHAVIOUR	1784	=head2 FORK BEHAVIOUR
1323		1785
1324	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:
1325		1787
…		…
1358		1820
1359	Known bugs will be fixed in the next release.	1821	Known bugs will be fixed in the next release.
1360		1822
1361	=head1 SEE ALSO	1823	=head1 SEE ALSO
1362		1824
1363	L<Coro::AIO>.	1825	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1826	more natural syntax.
1364		1827
1365	=head1 AUTHOR	1828	=head1 AUTHOR
1366		1829
1367	Marc Lehmann <schmorp@schmorp.de>	1830	Marc Lehmann <schmorp@schmorp.de>
1368	http://home.schmorp.de/	1831	http://home.schmorp.de/

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