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Revision 1.115 by root, Mon Sep 24 18:14:00 2007 UTC vs.
Revision 1.206 by root, Sun Jul 24 03:32:51 2011 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51
52	=head1 DESCRIPTION	31	=head1 DESCRIPTION
53		32
54	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
55	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
56		36
57	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
58	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
59	will still block, but you can do something else in the meantime. This	39	will still block, but you can do something else in the meantime. This
60	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
64	on a RAID volume or over NFS when you do a number of stat operations	44	on a RAID volume or over NFS when you do a number of stat operations
65	concurrently.	45	concurrently.
66		46
67	While most of this works on all types of file descriptors (for	47	While most of this works on all types of file descriptors (for
68	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
69	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
70	inefficient. Use an event loop for that (such as the L<Event|Event>	50	very inefficient. Use an event loop for that (such as the L<EV>
71	module): IO::AIO will naturally fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
72		52
73	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
74	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
75	in perl, and the threads created by this module will not be visible	55	in perl, and the threads created by this module will not be visible
…		…
85	yourself, always call C<poll_cb> from within the same thread, or never	65	yourself, always call C<poll_cb> from within the same thread, or never
86	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
87		67
88	=head2 EXAMPLE	68	=head2 EXAMPLE
89		69
90	This is a simple example that uses the Event module and loads	70	This is a simple example that uses the EV module and loads
91	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
92		72
93	use Fcntl;	73	use Fcntl;
94	use Event;	74	use EV;
95	use IO::AIO;	75	use IO::AIO;
96		76
97	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
98	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
99	poll => 'r',
100	cb => \&IO::AIO::poll_cb);
101		79
102	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
103	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
104	my $fh = shift	82	my $fh = shift
105	or die "error while opening: $!";	83	or die "error while opening: $!";
106		84
107	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
108	my $size = -s $fh;	86	my $size = -s $fh;
…		…
117		95
118	# file contents now in $contents	96	# file contents now in $contents
119	print $contents;	97	print $contents;
120		98
121	# exit event loop and program	99	# exit event loop and program
122	Event::unloop;	100	EV::unloop;
123	};	101	};
124	};	102	};
125		103
126	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
127	# check for sockets etc. etc.	105	# check for sockets etc. etc.
128		106
129	# process events as long as there are some:	107	# process events as long as there are some:
130	Event::loop;	108	EV::loop;
131		109
132	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
133		111
134	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
135	directly visible to Perl.	113	directly visible to Perl.
…		…
183		161
184	=cut	162	=cut
185		163
186	package IO::AIO;	164	package IO::AIO;
187		165
188	no warnings;	166	use Carp ();
189	use strict 'vars';	167
		168	use common::sense;
190		169
191	use base 'Exporter';	170	use base 'Exporter';
192		171
193	BEGIN {	172	BEGIN {
194	our $VERSION = '2.41';	173	our $VERSION = '4.0';
195		174
196	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
197	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
198	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
		178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
		179	aio_pathsync aio_readahead
		180	aio_rename aio_link aio_move aio_copy aio_group
199	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
200	aio_chown aio_chmod aio_utime aio_truncate);	182	aio_chmod aio_utime aio_truncate
		183	aio_msync aio_mtouch aio_mlock aio_mlockall
		184	aio_statvfs);
		185
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	188	min_parallel max_parallel max_idle idle_timeout
204	nreqs nready npending nthreads	189	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	190	max_poll_time max_poll_reqs
		191	sendfile fadvise madvise
		192	mmap munmap munlock munlockall);
		193
		194	push @AIO_REQ, qw(aio_busy); # not exported
206		195
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	196	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		197
209	require XSLoader;	198	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	199	XSLoader::load ("IO::AIO", $VERSION);
211	}	200	}
212		201
213	=head1 FUNCTIONS	202	=head1 FUNCTIONS
		203
		204	=head2 QUICK OVERVIEW
		205
		206	This section simply lists the prototypes of the most important functions
		207	for quick reference. See the following sections for function-by-function
		208	documentation.
		209
		210	aio_open $pathname, $flags, $mode, $callback->($fh)
		211	aio_close $fh, $callback->($status)
		212	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		214	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		215	aio_readahead $fh,$offset,$length, $callback->($retval)
		216	aio_stat $fh_or_path, $callback->($status)
		217	aio_lstat $fh, $callback->($status)
		218	aio_statvfs $fh_or_path, $callback->($statvfs)
		219	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		220	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		221	aio_truncate $fh_or_path, $offset, $callback->($status)
		222	aio_chmod $fh_or_path, $mode, $callback->($status)
		223	aio_unlink $pathname, $callback->($status)
		224	aio_mknod $path, $mode, $dev, $callback->($status)
		225	aio_link $srcpath, $dstpath, $callback->($status)
		226	aio_symlink $srcpath, $dstpath, $callback->($status)
		227	aio_readlink $path, $callback->($link)
		228	aio_realpath $path, $callback->($link)
		229	aio_rename $srcpath, $dstpath, $callback->($status)
		230	aio_mkdir $pathname, $mode, $callback->($status)
		231	aio_rmdir $pathname, $callback->($status)
		232	aio_readdir $pathname, $callback->($entries)
		233	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		234	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		235	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		236	aio_load $path, $data, $callback->($status)
		237	aio_copy $srcpath, $dstpath, $callback->($status)
		238	aio_move $srcpath, $dstpath, $callback->($status)
		239	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		240	aio_rmtree $path, $callback->($status)
		241	aio_sync $callback->($status)
		242	aio_syncfs $fh, $callback->($status)
		243	aio_fsync $fh, $callback->($status)
		244	aio_fdatasync $fh, $callback->($status)
		245	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		246	aio_pathsync $path, $callback->($status)
		247	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		248	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		249	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		250	aio_mlockall $flags, $callback->($status)
		251	aio_group $callback->(...)
		252	aio_nop $callback->()
		253
		254	$prev_pri = aioreq_pri [$pri]
		255	aioreq_nice $pri_adjust
		256
		257	IO::AIO::poll_wait
		258	IO::AIO::poll_cb
		259	IO::AIO::poll
		260	IO::AIO::flush
		261	IO::AIO::max_poll_reqs $nreqs
		262	IO::AIO::max_poll_time $seconds
		263	IO::AIO::min_parallel $nthreads
		264	IO::AIO::max_parallel $nthreads
		265	IO::AIO::max_idle $nthreads
		266	IO::AIO::idle_timeout $seconds
		267	IO::AIO::max_outstanding $maxreqs
		268	IO::AIO::nreqs
		269	IO::AIO::nready
		270	IO::AIO::npending
		271
		272	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		273	IO::AIO::fadvise $fh, $offset, $len, $advice
		274	IO::AIO::madvise $scalar, $offset, $length, $advice
		275	IO::AIO::mprotect $scalar, $offset, $length, $protect
		276	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		277	IO::AIO::munlockall
214		278
215	=head2 AIO REQUEST FUNCTIONS	279	=head2 AIO REQUEST FUNCTIONS
216		280
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	281	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	282	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	283	and they all accept an additional (and optional) C<$callback> argument
220	which must be a code reference. This code reference will get called with	284	which must be a code reference. This code reference will get called with
221	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	285	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
222	perl, which usually delivers "false") as it's sole argument when the given	286	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	287	syscall has been executed asynchronously.
224		288
225	All functions expecting a filehandle keep a copy of the filehandle	289	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	290	internally until the request has finished.
227		291
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	305	your pathnames to the locale (or other) encoding in effect in the user
242	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	306	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	307	use something else to ensure your scalar has the correct contents.
244		308
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	309	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	310	handles correctly whether it is set or not.
247		311
248	=over 4	312	=over 4
249		313
250	=item $prev_pri = aioreq_pri [$pri]	314	=item $prev_pri = aioreq_pri [$pri]
251		315
…		…
298	by the umask in effect then the request is being executed, so better never	362	by the umask in effect then the request is being executed, so better never
299	change the umask.	363	change the umask.
300		364
301	Example:	365	Example:
302		366
303	aio_open "/etc/passwd", O_RDONLY, 0, sub {	367	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
304	if ($_[0]) {	368	if ($_[0]) {
305	print "open successful, fh is $_[0]\n";	369	print "open successful, fh is $_[0]\n";
306	...	370	...
307	} else {	371	} else {
308	die "open failed: $!\n";	372	die "open failed: $!\n";
309	}	373	}
310	};	374	};
311		375
		376	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		377	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		378	following POSIX and non-POSIX constants are available (missing ones on
		379	your system are, as usual, C<0>):
		380
		381	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		382	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		383	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		384
312		385
313	=item aio_close $fh, $callback->($status)	386	=item aio_close $fh, $callback->($status)
314		387
315	Asynchronously close a file and call the callback with the result	388	Asynchronously close a file and call the callback with the result
316	code. I<WARNING:> although accepted, you should not pass in a perl	389	code.
317	filehandle here, as perl will likely close the file descriptor another
318	time when the filehandle is destroyed. Normally, you can safely call perls
319	C<close> or just let filehandles go out of scope.
320		390
321	This is supposed to be a bug in the API, so that might change. It's	391	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
322	therefore best to avoid this function.	392	closing the file descriptor associated with the filehandle itself.
323		393
		394	Therefore, C<aio_close> will not close the filehandle - instead it will
		395	use dup2 to overwrite the file descriptor with the write-end of a pipe
		396	(the pipe fd will be created on demand and will be cached).
		397
		398	Or in other words: the file descriptor will be closed, but it will not be
		399	free for reuse until the perl filehandle is closed.
		400
		401	=cut
324		402
325	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	403	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
326		404
327	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	405	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
328		406
329	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>	407	Reads or writes C<$length> bytes from or to the specified C<$fh> and
330	into the scalar given by C<$data> and offset C<$dataoffset> and calls the	408	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
331	callback without the actual number of bytes read (or -1 on error, just	409	and calls the callback without the actual number of bytes read (or -1 on
332	like the syscall).	410	error, just like the syscall).
		411
		412	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		413	offset plus the actual number of bytes read.
333		414
334	If C<$offset> is undefined, then the current file descriptor offset will	415	If C<$offset> is undefined, then the current file descriptor offset will
335	be used (and updated), otherwise the file descriptor offset will not be	416	be used (and updated), otherwise the file descriptor offset will not be
336	changed by these calls.	417	changed by these calls.
337		418
338	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.	419	If C<$length> is undefined in C<aio_write>, use the remaining length of
		420	C<$data>.
339		421
340	If C<$dataoffset> is less than zero, it will be counted from the end of	422	If C<$dataoffset> is less than zero, it will be counted from the end of
341	C<$data>.	423	C<$data>.
342		424
343	The C<$data> scalar I<MUST NOT> be modified in any way while the request	425	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
357		439
358	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	440	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
359	reading at byte offset C<$in_offset>, and starts writing at the current	441	reading at byte offset C<$in_offset>, and starts writing at the current
360	file offset of C<$out_fh>. Because of that, it is not safe to issue more	442	file offset of C<$out_fh>. Because of that, it is not safe to issue more
361	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	443	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
362	other.	444	other. The same C<$in_fh> works fine though, as this function does not
		445	move or use the file offset of C<$in_fh>.
363		446
		447	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		448	are written, and there is no way to find out how many more bytes have been
		449	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		450	number of bytes written to C<$out_fh>. Only if the result value equals
		451	C<$length> one can assume that C<$length> bytes have been read.
		452
		453	Unlike with other C<aio_> functions, it makes a lot of sense to use
		454	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		455	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		456	the socket I/O will be non-blocking. Note, however, that you can run
		457	into a trap where C<aio_sendfile> reads some data with readahead, then
		458	fails to write all data, and when the socket is ready the next time, the
		459	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		460	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		461	resource usage.
		462
364	This call tries to make use of a native C<sendfile> syscall to provide	463	This call tries to make use of a native C<sendfile>-like syscall to
365	zero-copy operation. For this to work, C<$out_fh> should refer to a	464	provide zero-copy operation. For this to work, C<$out_fh> should refer to
366	socket, and C<$in_fh> should refer to mmap'able file.	465	a socket, and C<$in_fh> should refer to an mmap'able file.
367		466
368	If the native sendfile call fails or is not implemented, it will be	467	If a native sendfile cannot be found or it fails with C<ENOSYS>,
369	emulated, so you can call C<aio_sendfile> on any type of filehandle	468	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		469	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
370	regardless of the limitations of the operating system.	470	type of filehandle regardless of the limitations of the operating system.
371		471
372	Please note, however, that C<aio_sendfile> can read more bytes from	472	As native sendfile syscalls (as practically any non-POSIX interface hacked
373	C<$in_fh> than are written, and there is no way to find out how many	473	together in a hurry to improve benchmark numbers) tend to be rather buggy
374	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	474	on many systems, this implementation tries to work around some known bugs
375	provides the number of bytes written to C<$out_fh>. Only if the result	475	in Linux and FreeBSD kernels (probably others, too), but that might fail,
376	value equals C<$length> one can assume that C<$length> bytes have been	476	so you really really should check the return value of C<aio_sendfile> -
377	read.	477	fewre bytes than expected might have been transferred.
378		478
379		479
380	=item aio_readahead $fh,$offset,$length, $callback->($retval)	480	=item aio_readahead $fh,$offset,$length, $callback->($retval)
381		481
382	C<aio_readahead> populates the page cache with data from a file so that	482	C<aio_readahead> populates the page cache with data from a file so that
…		…
405		505
406	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	506	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
407	error when stat'ing a large file, the results will be silently truncated	507	error when stat'ing a large file, the results will be silently truncated
408	unless perl itself is compiled with large file support.	508	unless perl itself is compiled with large file support.
409		509
		510	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		511	following constants and functions (if not implemented, the constants will
		512	be C<0> and the functions will either C<croak> or fall back on traditional
		513	behaviour).
		514
		515	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		516	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		517	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		518
410	Example: Print the length of F</etc/passwd>:	519	Example: Print the length of F</etc/passwd>:
411		520
412	aio_stat "/etc/passwd", sub {	521	aio_stat "/etc/passwd", sub {
413	$_[0] and die "stat failed: $!";	522	$_[0] and die "stat failed: $!";
414	print "size is ", -s _, "\n";	523	print "size is ", -s _, "\n";
415	};	524	};
416		525
417		526
		527	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		528
		529	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		530	whether a file handle or path was passed.
		531
		532	On success, the callback is passed a hash reference with the following
		533	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		534	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		535	is passed.
		536
		537	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		538	C<ST_NOSUID>.
		539
		540	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		541	their correct value when available, or to C<0> on systems that do
		542	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		543	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		544	C<ST_NODIRATIME> and C<ST_RELATIME>.
		545
		546	Example: stat C</wd> and dump out the data if successful.
		547
		548	aio_statvfs "/wd", sub {
		549	my $f = $_[0]
		550	or die "statvfs: $!";
		551
		552	use Data::Dumper;
		553	say Dumper $f;
		554	};
		555
		556	# result:
		557	{
		558	bsize => 1024,
		559	bfree => 4333064312,
		560	blocks => 10253828096,
		561	files => 2050765568,
		562	flag => 4096,
		563	favail => 2042092649,
		564	bavail => 4333064312,
		565	ffree => 2042092649,
		566	namemax => 255,
		567	frsize => 1024,
		568	fsid => 1810
		569	}
		570
		571
418	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	572	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
419		573
420	Works like perl's C<utime> function (including the special case of $atime	574	Works like perl's C<utime> function (including the special case of $atime
421	and $mtime being undef). Fractional times are supported if the underlying	575	and $mtime being undef). Fractional times are supported if the underlying
422	syscalls support them.	576	syscalls support them.
…		…
470		624
471	The only (POSIX-) portable way of calling this function is:	625	The only (POSIX-) portable way of calling this function is:
472		626
473	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	627	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
474		628
		629	See C<aio_stat> for info about some potentially helpful extra constants
		630	and functions.
475		631
476	=item aio_link $srcpath, $dstpath, $callback->($status)	632	=item aio_link $srcpath, $dstpath, $callback->($status)
477		633
478	Asynchronously create a new link to the existing object at C<$srcpath> at	634	Asynchronously create a new link to the existing object at C<$srcpath> at
479	the path C<$dstpath> and call the callback with the result code.	635	the path C<$dstpath> and call the callback with the result code.
…		…
490	Asynchronously read the symlink specified by C<$path> and pass it to	646	Asynchronously read the symlink specified by C<$path> and pass it to
491	the callback. If an error occurs, nothing or undef gets passed to the	647	the callback. If an error occurs, nothing or undef gets passed to the
492	callback.	648	callback.
493		649
494		650
		651	=item aio_realpath $path, $callback->($path)
		652
		653	Asynchronously make the path absolute and resolve any symlinks in
		654	C<$path>. The resulting path only consists of directories (Same as
		655	L<Cwd::realpath>).
		656
		657	This request can be used to get the absolute path of the current working
		658	directory by passing it a path of F<.> (a single dot).
		659
		660
495	=item aio_rename $srcpath, $dstpath, $callback->($status)	661	=item aio_rename $srcpath, $dstpath, $callback->($status)
496		662
497	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	663	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
498	rename(2) and call the callback with the result code.	664	rename(2) and call the callback with the result code.
499		665
…		…
515		681
516	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	682	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
517	directory (i.e. opendir + readdir + closedir). The entries will not be	683	directory (i.e. opendir + readdir + closedir). The entries will not be
518	sorted, and will B<NOT> include the C<.> and C<..> entries.	684	sorted, and will B<NOT> include the C<.> and C<..> entries.
519		685
520	The callback a single argument which is either C<undef> or an array-ref	686	The callback is passed a single argument which is either C<undef> or an
521	with the filenames.	687	array-ref with the filenames.
		688
		689
		690	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		691
		692	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		693	behaviour and output format. In case of an error, C<$entries> will be
		694	C<undef>.
		695
		696	The flags are a combination of the following constants, ORed together (the
		697	flags will also be passed to the callback, possibly modified):
		698
		699	=over 4
		700
		701	=item IO::AIO::READDIR_DENTS
		702
		703	When this flag is off, then the callback gets an arrayref consisting of
		704	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		705	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		706	entry in more detail.
		707
		708	C<$name> is the name of the entry.
		709
		710	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		711
		712	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		713	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		714	C<IO::AIO::DT_WHT>.
		715
		716	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		717	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		718	scalars are read-only: you can not modify them.
		719
		720	C<$inode> is the inode number (which might not be exact on systems with 64
		721	bit inode numbers and 32 bit perls). This field has unspecified content on
		722	systems that do not deliver the inode information.
		723
		724	=item IO::AIO::READDIR_DIRS_FIRST
		725
		726	When this flag is set, then the names will be returned in an order where
		727	likely directories come first, in optimal stat order. This is useful when
		728	you need to quickly find directories, or you want to find all directories
		729	while avoiding to stat() each entry.
		730
		731	If the system returns type information in readdir, then this is used
		732	to find directories directly. Otherwise, likely directories are names
		733	beginning with ".", or otherwise names with no dots, of which names with
		734	short names are tried first.
		735
		736	=item IO::AIO::READDIR_STAT_ORDER
		737
		738	When this flag is set, then the names will be returned in an order
		739	suitable for stat()'ing each one. That is, when you plan to stat()
		740	all files in the given directory, then the returned order will likely
		741	be fastest.
		742
		743	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		744	the likely dirs come first, resulting in a less optimal stat order.
		745
		746	=item IO::AIO::READDIR_FOUND_UNKNOWN
		747
		748	This flag should not be set when calling C<aio_readdirx>. Instead, it
		749	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		750	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		751	C<$type>'s are known, which can be used to speed up some algorithms.
		752
		753	=back
522		754
523		755
524	=item aio_load $path, $data, $callback->($status)	756	=item aio_load $path, $data, $callback->($status)
525		757
526	This is a composite request that tries to fully load the given file into	758	This is a composite request that tries to fully load the given file into
527	memory. Status is the same as with aio_read.	759	memory. Status is the same as with aio_read.
528		760
529	=cut	761	=cut
530		762
531	sub aio_load($$;$) {	763	sub aio_load($$;$) {
532	aio_block {
533	my ($path, undef, $cb) = @_;	764	my ($path, undef, $cb) = @_;
534	my $data = \$_[1];	765	my $data = \$_[1];
535		766
536	my $pri = aioreq_pri;	767	my $pri = aioreq_pri;
537	my $grp = aio_group $cb;	768	my $grp = aio_group $cb;
		769
		770	aioreq_pri $pri;
		771	add $grp aio_open $path, O_RDONLY, 0, sub {
		772	my $fh = shift
		773	or return $grp->result (-1);
538		774
539	aioreq_pri $pri;	775	aioreq_pri $pri;
540	add $grp aio_open $path, O_RDONLY, 0, sub {
541	my $fh = shift
542	or return $grp->result (-1);
543
544	aioreq_pri $pri;
545	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	776	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
546	$grp->result ($_[0]);	777	$grp->result ($_[0]);
547	};
548	};	778	};
549
550	$grp
551	}	779	};
		780
		781	$grp
552	}	782	}
553		783
554	=item aio_copy $srcpath, $dstpath, $callback->($status)	784	=item aio_copy $srcpath, $dstpath, $callback->($status)
555		785
556	Try to copy the I<file> (directories not supported as either source or	786	Try to copy the I<file> (directories not supported as either source or
557	destination) from C<$srcpath> to C<$dstpath> and call the callback with	787	destination) from C<$srcpath> to C<$dstpath> and call the callback with
558	the C<0> (error) or C<-1> ok.	788	a status of C<0> (ok) or C<-1> (error, see C<$!>).
559		789
560	This is a composite request that it creates the destination file with	790	This is a composite request that creates the destination file with
561	mode 0200 and copies the contents of the source file into it using	791	mode 0200 and copies the contents of the source file into it using
562	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	792	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
563	uid/gid, in that order.	793	uid/gid, in that order.
564		794
565	If an error occurs, the partial destination file will be unlinked, if	795	If an error occurs, the partial destination file will be unlinked, if
…		…
567	errors are being ignored.	797	errors are being ignored.
568		798
569	=cut	799	=cut
570		800
571	sub aio_copy($$;$) {	801	sub aio_copy($$;$) {
572	aio_block {
573	my ($src, $dst, $cb) = @_;	802	my ($src, $dst, $cb) = @_;
574		803
575	my $pri = aioreq_pri;	804	my $pri = aioreq_pri;
576	my $grp = aio_group $cb;	805	my $grp = aio_group $cb;
577		806
578	aioreq_pri $pri;	807	aioreq_pri $pri;
579	add $grp aio_open $src, O_RDONLY, 0, sub {	808	add $grp aio_open $src, O_RDONLY, 0, sub {
580	if (my $src_fh = $_[0]) {	809	if (my $src_fh = $_[0]) {
581	my @stat = stat $src_fh;	810	my @stat = stat $src_fh; # hmm, might block over nfs?
582		811
583	aioreq_pri $pri;	812	aioreq_pri $pri;
584	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	813	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
585	if (my $dst_fh = $_[0]) {	814	if (my $dst_fh = $_[0]) {
586	aioreq_pri $pri;	815	aioreq_pri $pri;
587	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	816	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
588	if ($_[0] == $stat[7]) {	817	if ($_[0] == $stat[7]) {
589	$grp->result (0);	818	$grp->result (0);
590	close $src_fh;	819	close $src_fh;
591		820
592	# those should not normally block. should. should.
593	utime $stat[8], $stat[9], $dst;
594	chmod $stat[2] & 07777, $dst_fh;
595	chown $stat[4], $stat[5], $dst_fh;
596	close $dst_fh;
597	} else {	821	my $ch = sub {
598	$grp->result (-1);
599	close $src_fh;
600	close $dst_fh;
601
602	aioreq $pri;	822	aioreq_pri $pri;
		823	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		824	aioreq_pri $pri;
		825	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		826	aioreq_pri $pri;
603	add $grp aio_unlink $dst;	827	add $grp aio_close $dst_fh;
		828	}
		829	};
604	}	830	};
		831
		832	aioreq_pri $pri;
		833	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		834	if ($_[0] < 0 && $! == ENOSYS) {
		835	aioreq_pri $pri;
		836	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		837	} else {
		838	$ch->();
		839	}
		840	};
		841	} else {
		842	$grp->result (-1);
		843	close $src_fh;
		844	close $dst_fh;
		845
		846	aioreq $pri;
		847	add $grp aio_unlink $dst;
605	};	848	}
606	} else {
607	$grp->result (-1);
608	}	849	};
		850	} else {
		851	$grp->result (-1);
609	},	852	}
610
611	} else {
612	$grp->result (-1);
613	}	853	},
		854
		855	} else {
		856	$grp->result (-1);
614	};	857	}
615
616	$grp
617	}	858	};
		859
		860	$grp
618	}	861	}
619		862
620	=item aio_move $srcpath, $dstpath, $callback->($status)	863	=item aio_move $srcpath, $dstpath, $callback->($status)
621		864
622	Try to move the I<file> (directories not supported as either source or	865	Try to move the I<file> (directories not supported as either source or
623	destination) from C<$srcpath> to C<$dstpath> and call the callback with	866	destination) from C<$srcpath> to C<$dstpath> and call the callback with
624	the C<0> (error) or C<-1> ok.	867	a status of C<0> (ok) or C<-1> (error, see C<$!>).
625		868
626	This is a composite request that tries to rename(2) the file first. If	869	This is a composite request that tries to rename(2) the file first; if
627	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	870	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
628	that is successful, unlinking the C<$srcpath>.	871	that is successful, unlinks the C<$srcpath>.
629		872
630	=cut	873	=cut
631		874
632	sub aio_move($$;$) {	875	sub aio_move($$;$) {
633	aio_block {
634	my ($src, $dst, $cb) = @_;	876	my ($src, $dst, $cb) = @_;
635		877
636	my $pri = aioreq_pri;	878	my $pri = aioreq_pri;
637	my $grp = aio_group $cb;	879	my $grp = aio_group $cb;
638		880
639	aioreq_pri $pri;	881	aioreq_pri $pri;
640	add $grp aio_rename $src, $dst, sub {	882	add $grp aio_rename $src, $dst, sub {
641	if ($_[0] && $! == EXDEV) {	883	if ($_[0] && $! == EXDEV) {
642	aioreq_pri $pri;	884	aioreq_pri $pri;
643	add $grp aio_copy $src, $dst, sub {	885	add $grp aio_copy $src, $dst, sub {
644	$grp->result ($_[0]);
645
646	if (!$_[0]) {
647	aioreq_pri $pri;
648	add $grp aio_unlink $src;
649	}
650	};
651	} else {
652	$grp->result ($_[0]);	886	$grp->result ($_[0]);
		887
		888	unless ($_[0]) {
		889	aioreq_pri $pri;
		890	add $grp aio_unlink $src;
		891	}
653	}	892	};
		893	} else {
		894	$grp->result ($_[0]);
654	};	895	}
655
656	$grp
657	}	896	};
		897
		898	$grp
658	}	899	}
659		900
660	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	901	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
661		902
662	Scans a directory (similar to C<aio_readdir>) but additionally tries to	903	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
682		923
683	Implementation notes.	924	Implementation notes.
684		925
685	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	926	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
686		927
		928	If readdir returns file type information, then this is used directly to
		929	find directories.
		930
687	After reading the directory, the modification time, size etc. of the	931	Otherwise, after reading the directory, the modification time, size etc.
688	directory before and after the readdir is checked, and if they match (and	932	of the directory before and after the readdir is checked, and if they
689	isn't the current time), the link count will be used to decide how many	933	match (and isn't the current time), the link count will be used to decide
690	entries are directories (if >= 2). Otherwise, no knowledge of the number	934	how many entries are directories (if >= 2). Otherwise, no knowledge of the
691	of subdirectories will be assumed.	935	number of subdirectories will be assumed.
692		936
693	Then entries will be sorted into likely directories (everything without	937	Then entries will be sorted into likely directories a non-initial dot
694	a non-initial dot currently) and likely non-directories (everything	938	currently) and likely non-directories (see C<aio_readdirx>). Then every
695	else). Then every entry plus an appended C</.> will be C<stat>'ed,	939	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
696	likely directories first. If that succeeds, it assumes that the entry	940	in order of their inode numbers. If that succeeds, it assumes that the
697	is a directory or a symlink to directory (which will be checked	941	entry is a directory or a symlink to directory (which will be checked
698	seperately). This is often faster than stat'ing the entry itself because	942	seperately). This is often faster than stat'ing the entry itself because
699	filesystems might detect the type of the entry without reading the inode	943	filesystems might detect the type of the entry without reading the inode
700	data (e.g. ext2fs filetype feature).	944	data (e.g. ext2fs filetype feature), even on systems that cannot return
		945	the filetype information on readdir.
701		946
702	If the known number of directories (link count - 2) has been reached, the	947	If the known number of directories (link count - 2) has been reached, the
703	rest of the entries is assumed to be non-directories.	948	rest of the entries is assumed to be non-directories.
704		949
705	This only works with certainty on POSIX (= UNIX) filesystems, which	950	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
710	directory counting heuristic.	955	directory counting heuristic.
711		956
712	=cut	957	=cut
713		958
714	sub aio_scandir($$;$) {	959	sub aio_scandir($$;$) {
715	aio_block {
716	my ($path, $maxreq, $cb) = @_;	960	my ($path, $maxreq, $cb) = @_;
717		961
718	my $pri = aioreq_pri;	962	my $pri = aioreq_pri;
719		963
720	my $grp = aio_group $cb;	964	my $grp = aio_group $cb;
721		965
722	$maxreq = 4 if $maxreq <= 0;	966	$maxreq = 4 if $maxreq <= 0;
723		967
724	# stat once	968	# stat once
		969	aioreq_pri $pri;
		970	add $grp aio_stat $path, sub {
		971	return $grp->result () if $_[0];
		972	my $now = time;
		973	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		974
		975	# read the directory entries
725	aioreq_pri $pri;	976	aioreq_pri $pri;
726	add $grp aio_stat $path, sub {	977	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		978	my $entries = shift
727	return $grp->result () if $_[0];	979	or return $grp->result ();
728	my $now = time;
729	my $hash1 = join ":", (stat _)[0,1,3,7,9];
730		980
731	# read the directory entries	981	# stat the dir another time
732	aioreq_pri $pri;	982	aioreq_pri $pri;
733	add $grp aio_readdir $path, sub {
734	my $entries = shift
735	or return $grp->result ();
736
737	# stat the dir another time
738	aioreq_pri $pri;
739	add $grp aio_stat $path, sub {	983	add $grp aio_stat $path, sub {
740	my $hash2 = join ":", (stat _)[0,1,3,7,9];	984	my $hash2 = join ":", (stat _)[0,1,3,7,9];
741		985
742	my $ndirs;	986	my $ndirs;
743		987
744	# take the slow route if anything looks fishy	988	# take the slow route if anything looks fishy
745	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	989	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
746	$ndirs = -1;	990	$ndirs = -1;
747	} else {	991	} else {
748	# if nlink == 2, we are finished	992	# if nlink == 2, we are finished
749	# on non-posix-fs's, we rely on nlink < 2	993	# for non-posix-fs's, we rely on nlink < 2
750	$ndirs = (stat _)[3] - 2	994	$ndirs = (stat _)[3] - 2
751	or return $grp->result ([], $entries);	995	or return $grp->result ([], $entries);
752	}	996	}
753		997
754	# sort into likely dirs and likely nondirs
755	# dirs == files without ".", short entries first
756	$entries = [map $_->[0],
757	sort { $b->[1] cmp $a->[1] }
758	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
759	@$entries];
760
761	my (@dirs, @nondirs);	998	my (@dirs, @nondirs);
762		999
763	my $statgrp = add $grp aio_group sub {	1000	my $statgrp = add $grp aio_group sub {
764	$grp->result (\@dirs, \@nondirs);	1001	$grp->result (\@dirs, \@nondirs);
765	};	1002	};
766		1003
767	limit $statgrp $maxreq;	1004	limit $statgrp $maxreq;
768	feed $statgrp sub {	1005	feed $statgrp sub {
769	return unless @$entries;	1006	return unless @$entries;
770	my $entry = pop @$entries;	1007	my $entry = shift @$entries;
771		1008
772	aioreq_pri $pri;	1009	aioreq_pri $pri;
773	add $statgrp aio_stat "$path/$entry/.", sub {	1010	add $statgrp aio_stat "$path/$entry/.", sub {
774	if ($_[0] < 0) {	1011	if ($_[0] < 0) {
775	push @nondirs, $entry;	1012	push @nondirs, $entry;
776	} else {	1013	} else {
777	# need to check for real directory	1014	# need to check for real directory
778	aioreq_pri $pri;	1015	aioreq_pri $pri;
779	add $statgrp aio_lstat "$path/$entry", sub {	1016	add $statgrp aio_lstat "$path/$entry", sub {
780	if (-d _) {	1017	if (-d _) {
781	push @dirs, $entry;	1018	push @dirs, $entry;
782		1019
783	unless (--$ndirs) {	1020	unless (--$ndirs) {
784	push @nondirs, @$entries;	1021	push @nondirs, @$entries;
785	feed $statgrp;	1022	feed $statgrp;
786	}
787	} else {
788	push @nondirs, $entry;
789	}	1023	}
		1024	} else {
		1025	push @nondirs, $entry;
790	}	1026	}
791	}	1027	}
792	};	1028	}
793	};	1029	};
794	};	1030	};
795	};	1031	};
796	};	1032	};
797
798	$grp
799	}	1033	};
		1034
		1035	$grp
800	}	1036	}
801		1037
802	=item aio_rmtree $path, $callback->($status)	1038	=item aio_rmtree $path, $callback->($status)
803		1039
804	Delete a directory tree starting (and including) C<$path>, return the	1040	Delete a directory tree starting (and including) C<$path>, return the
…		…
808		1044
809	=cut	1045	=cut
810		1046
811	sub aio_rmtree;	1047	sub aio_rmtree;
812	sub aio_rmtree($;$) {	1048	sub aio_rmtree($;$) {
813	aio_block {
814	my ($path, $cb) = @_;	1049	my ($path, $cb) = @_;
815		1050
816	my $pri = aioreq_pri;	1051	my $pri = aioreq_pri;
817	my $grp = aio_group $cb;	1052	my $grp = aio_group $cb;
818		1053
819	aioreq_pri $pri;	1054	aioreq_pri $pri;
820	add $grp aio_scandir $path, 0, sub {	1055	add $grp aio_scandir $path, 0, sub {
821	my ($dirs, $nondirs) = @_;	1056	my ($dirs, $nondirs) = @_;
822		1057
823	my $dirgrp = aio_group sub {	1058	my $dirgrp = aio_group sub {
824	add $grp aio_rmdir $path, sub {	1059	add $grp aio_rmdir $path, sub {
825	$grp->result ($_[0]);	1060	$grp->result ($_[0]);
826	};
827	};	1061	};
828
829	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
830	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
831
832	add $grp $dirgrp;
833	};	1062	};
834		1063
835	$grp	1064	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1065	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1066
		1067	add $grp $dirgrp;
836	}	1068	};
		1069
		1070	$grp
837	}	1071	}
		1072
		1073	=item aio_sync $callback->($status)
		1074
		1075	Asynchronously call sync and call the callback when finished.
838		1076
839	=item aio_fsync $fh, $callback->($status)	1077	=item aio_fsync $fh, $callback->($status)
840		1078
841	Asynchronously call fsync on the given filehandle and call the callback	1079	Asynchronously call fsync on the given filehandle and call the callback
842	with the fsync result code.	1080	with the fsync result code.
…		…
846	Asynchronously call fdatasync on the given filehandle and call the	1084	Asynchronously call fdatasync on the given filehandle and call the
847	callback with the fdatasync result code.	1085	callback with the fdatasync result code.
848		1086
849	If this call isn't available because your OS lacks it or it couldn't be	1087	If this call isn't available because your OS lacks it or it couldn't be
850	detected, it will be emulated by calling C<fsync> instead.	1088	detected, it will be emulated by calling C<fsync> instead.
		1089
		1090	=item aio_syncfs $fh, $callback->($status)
		1091
		1092	Asynchronously call the syncfs syscall to sync the filesystem associated
		1093	to the given filehandle and call the callback with the syncfs result
		1094	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1095	errno to C<ENOSYS> nevertheless.
		1096
		1097	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1098
		1099	Sync the data portion of the file specified by C<$offset> and C<$length>
		1100	to disk (but NOT the metadata), by calling the Linux-specific
		1101	sync_file_range call. If sync_file_range is not available or it returns
		1102	ENOSYS, then fdatasync or fsync is being substituted.
		1103
		1104	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1105	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1106	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1107	manpage for details.
		1108
		1109	=item aio_pathsync $path, $callback->($status)
		1110
		1111	This request tries to open, fsync and close the given path. This is a
		1112	composite request intended to sync directories after directory operations
		1113	(E.g. rename). This might not work on all operating systems or have any
		1114	specific effect, but usually it makes sure that directory changes get
		1115	written to disc. It works for anything that can be opened for read-only,
		1116	not just directories.
		1117
		1118	Future versions of this function might fall back to other methods when
		1119	C<fsync> on the directory fails (such as calling C<sync>).
		1120
		1121	Passes C<0> when everything went ok, and C<-1> on error.
		1122
		1123	=cut
		1124
		1125	sub aio_pathsync($;$) {
		1126	my ($path, $cb) = @_;
		1127
		1128	my $pri = aioreq_pri;
		1129	my $grp = aio_group $cb;
		1130
		1131	aioreq_pri $pri;
		1132	add $grp aio_open $path, O_RDONLY, 0, sub {
		1133	my ($fh) = @_;
		1134	if ($fh) {
		1135	aioreq_pri $pri;
		1136	add $grp aio_fsync $fh, sub {
		1137	$grp->result ($_[0]);
		1138
		1139	aioreq_pri $pri;
		1140	add $grp aio_close $fh;
		1141	};
		1142	} else {
		1143	$grp->result (-1);
		1144	}
		1145	};
		1146
		1147	$grp
		1148	}
		1149
		1150	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1151
		1152	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1153	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1154	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1155	scalar must only be modified in-place while an aio operation is pending on
		1156	it).
		1157
		1158	It calls the C<msync> function of your OS, if available, with the memory
		1159	area starting at C<$offset> in the string and ending C<$length> bytes
		1160	later. If C<$length> is negative, counts from the end, and if C<$length>
		1161	is C<undef>, then it goes till the end of the string. The flags can be
		1162	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1163	C<IO::AIO::MS_SYNC>.
		1164
		1165	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1166
		1167	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1168	scalars.
		1169
		1170	It touches (reads or writes) all memory pages in the specified
		1171	range inside the scalar. All caveats and parameters are the same
		1172	as for C<aio_msync>, above, except for flags, which must be either
		1173	C<0> (which reads all pages and ensures they are instantiated) or
		1174	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1175	writing an octet from it, which dirties the page).
		1176
		1177	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1178
		1179	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1180	scalars.
		1181
		1182	It reads in all the pages of the underlying storage into memory (if any)
		1183	and locks them, so they are not getting swapped/paged out or removed.
		1184
		1185	If C<$length> is undefined, then the scalar will be locked till the end.
		1186
		1187	On systems that do not implement C<mlock>, this function returns C<-1>
		1188	and sets errno to C<ENOSYS>.
		1189
		1190	Note that the corresponding C<munlock> is synchronous and is
		1191	documented under L<MISCELLANEOUS FUNCTIONS>.
		1192
		1193	Example: open a file, mmap and mlock it - both will be undone when
		1194	C<$data> gets destroyed.
		1195
		1196	open my $fh, "<", $path or die "$path: $!";
		1197	my $data;
		1198	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1199	aio_mlock $data; # mlock in background
		1200
		1201	=item aio_mlockall $flags, $callback->($status)
		1202
		1203	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1204	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1205
		1206	On systems that do not implement C<mlockall>, this function returns C<-1>
		1207	and sets errno to C<ENOSYS>.
		1208
		1209	Note that the corresponding C<munlockall> is synchronous and is
		1210	documented under L<MISCELLANEOUS FUNCTIONS>.
		1211
		1212	Example: asynchronously lock all current and future pages into memory.
		1213
		1214	aio_mlockall IO::AIO::MCL_FUTURE;
851		1215
852	=item aio_group $callback->(...)	1216	=item aio_group $callback->(...)
853		1217
854	This is a very special aio request: Instead of doing something, it is a	1218	This is a very special aio request: Instead of doing something, it is a
855	container for other aio requests, which is useful if you want to bundle	1219	container for other aio requests, which is useful if you want to bundle
…		…
905	=item cancel $req	1269	=item cancel $req
906		1270
907	Cancels the request, if possible. Has the effect of skipping execution	1271	Cancels the request, if possible. Has the effect of skipping execution
908	when entering the B<execute> state and skipping calling the callback when	1272	when entering the B<execute> state and skipping calling the callback when
909	entering the the B<result> state, but will leave the request otherwise	1273	entering the the B<result> state, but will leave the request otherwise
910	untouched. That means that requests that currently execute will not be	1274	untouched (with the exception of readdir). That means that requests that
911	stopped and resources held by the request will not be freed prematurely.	1275	currently execute will not be stopped and resources held by the request
		1276	will not be freed prematurely.
912		1277
913	=item cb $req $callback->(...)	1278	=item cb $req $callback->(...)
914		1279
915	Replace (or simply set) the callback registered to the request.	1280	Replace (or simply set) the callback registered to the request.
916		1281
…		…
967	Their lifetime, simplified, looks like this: when they are empty, they	1332	Their lifetime, simplified, looks like this: when they are empty, they
968	will finish very quickly. If they contain only requests that are in the	1333	will finish very quickly. If they contain only requests that are in the
969	C<done> state, they will also finish. Otherwise they will continue to	1334	C<done> state, they will also finish. Otherwise they will continue to
970	exist.	1335	exist.
971		1336
972	That means after creating a group you have some time to add requests. And	1337	That means after creating a group you have some time to add requests
973	in the callbacks of those requests, you can add further requests to the	1338	(precisely before the callback has been invoked, which is only done within
974	group. And only when all those requests have finished will the the group	1339	the C<poll_cb>). And in the callbacks of those requests, you can add
975	itself finish.	1340	further requests to the group. And only when all those requests have
		1341	finished will the the group itself finish.
976		1342
977	=over 4	1343	=over 4
978		1344
979	=item add $grp ...	1345	=item add $grp ...
980		1346
…		…
989	=item $grp->cancel_subs	1355	=item $grp->cancel_subs
990		1356
991	Cancel all subrequests and clears any feeder, but not the group request	1357	Cancel all subrequests and clears any feeder, but not the group request
992	itself. Useful when you queued a lot of events but got a result early.	1358	itself. Useful when you queued a lot of events but got a result early.
993		1359
		1360	The group request will finish normally (you cannot add requests to the
		1361	group).
		1362
994	=item $grp->result (...)	1363	=item $grp->result (...)
995		1364
996	Set the result value(s) that will be passed to the group callback when all	1365	Set the result value(s) that will be passed to the group callback when all
997	subrequests have finished and set thre groups errno to the current value	1366	subrequests have finished and set the groups errno to the current value
998	of errno (just like calling C<errno> without an error number). By default,	1367	of errno (just like calling C<errno> without an error number). By default,
999	no argument will be passed and errno is zero.	1368	no argument will be passed and errno is zero.
1000		1369
1001	=item $grp->errno ([$errno])	1370	=item $grp->errno ([$errno])
1002		1371
…		…
1013	=item feed $grp $callback->($grp)	1382	=item feed $grp $callback->($grp)
1014		1383
1015	Sets a feeder/generator on this group: every group can have an attached	1384	Sets a feeder/generator on this group: every group can have an attached
1016	generator that generates requests if idle. The idea behind this is that,	1385	generator that generates requests if idle. The idea behind this is that,
1017	although you could just queue as many requests as you want in a group,	1386	although you could just queue as many requests as you want in a group,
1018	this might starve other requests for a potentially long time. For	1387	this might starve other requests for a potentially long time. For example,
1019	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1388	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1020	requests, delaying any later requests for a long time.	1389	delaying any later requests for a long time.
1021		1390
1022	To avoid this, and allow incremental generation of requests, you can	1391	To avoid this, and allow incremental generation of requests, you can
1023	instead a group and set a feeder on it that generates those requests. The	1392	instead a group and set a feeder on it that generates those requests. The
1024	feed callback will be called whenever there are few enough (see C<limit>,	1393	feed callback will be called whenever there are few enough (see C<limit>,
1025	below) requests active in the group itself and is expected to queue more	1394	below) requests active in the group itself and is expected to queue more
…		…
1029	not impose any limits).	1398	not impose any limits).
1030		1399
1031	If the feed does not queue more requests when called, it will be	1400	If the feed does not queue more requests when called, it will be
1032	automatically removed from the group.	1401	automatically removed from the group.
1033		1402
1034	If the feed limit is C<0>, it will be set to C<2> automatically.	1403	If the feed limit is C<0> when this method is called, it will be set to
		1404	C<2> automatically.
1035		1405
1036	Example:	1406	Example:
1037		1407
1038	# stat all files in @files, but only ever use four aio requests concurrently:	1408	# stat all files in @files, but only ever use four aio requests concurrently:
1039		1409
…		…
1051	Sets the feeder limit for the group: The feeder will be called whenever	1421	Sets the feeder limit for the group: The feeder will be called whenever
1052	the group contains less than this many requests.	1422	the group contains less than this many requests.
1053		1423
1054	Setting the limit to C<0> will pause the feeding process.	1424	Setting the limit to C<0> will pause the feeding process.
1055		1425
		1426	The default value for the limit is C<0>, but note that setting a feeder
		1427	automatically bumps it up to C<2>.
		1428
1056	=back	1429	=back
1057		1430
1058	=head2 SUPPORT FUNCTIONS	1431	=head2 SUPPORT FUNCTIONS
1059		1432
1060	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1433	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1062	=over 4	1435	=over 4
1063		1436
1064	=item $fileno = IO::AIO::poll_fileno	1437	=item $fileno = IO::AIO::poll_fileno
1065		1438
1066	Return the I<request result pipe file descriptor>. This filehandle must be	1439	Return the I<request result pipe file descriptor>. This filehandle must be
1067	polled for reading by some mechanism outside this module (e.g. Event or	1440	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1068	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1441	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1069	to call C<poll_cb> to check the results.	1442	you have to call C<poll_cb> to check the results.
1070		1443
1071	See C<poll_cb> for an example.	1444	See C<poll_cb> for an example.
1072		1445
1073	=item IO::AIO::poll_cb	1446	=item IO::AIO::poll_cb
1074		1447
1075	Process some outstanding events on the result pipe. You have to call this	1448	Process some outstanding events on the result pipe. You have to call
1076	regularly. Returns the number of events processed. Returns immediately	1449	this regularly. Returns C<0> if all events could be processed (or there
1077	when no events are outstanding. The amount of events processed depends on	1450	were no events to process), or C<-1> if it returned earlier for whatever
1078	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1451	reason. Returns immediately when no events are outstanding. The amount of
		1452	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1453	C<IO::AIO::max_poll_time>.
1079		1454
1080	If not all requests were processed for whatever reason, the filehandle	1455	If not all requests were processed for whatever reason, the filehandle
1081	will still be ready when C<poll_cb> returns.	1456	will still be ready when C<poll_cb> returns, so normally you don't have to
		1457	do anything special to have it called later.
		1458
		1459	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1460	ready, it can be beneficial to call this function from loops which submit
		1461	a lot of requests, to make sure the results get processed when they become
		1462	available and not just when the loop is finished and the event loop takes
		1463	over again. This function returns very fast when there are no outstanding
		1464	requests.
1082		1465
1083	Example: Install an Event watcher that automatically calls	1466	Example: Install an Event watcher that automatically calls
1084	IO::AIO::poll_cb with high priority:	1467	IO::AIO::poll_cb with high priority (more examples can be found in the
		1468	SYNOPSIS section, at the top of this document):
1085		1469
1086	Event->io (fd => IO::AIO::poll_fileno,	1470	Event->io (fd => IO::AIO::poll_fileno,
1087	poll => 'r', async => 1,	1471	poll => 'r', async => 1,
1088	cb => \&IO::AIO::poll_cb);	1472	cb => \&IO::AIO::poll_cb);
		1473
		1474	=item IO::AIO::poll_wait
		1475
		1476	If there are any outstanding requests and none of them in the result
		1477	phase, wait till the result filehandle becomes ready for reading (simply
		1478	does a C<select> on the filehandle. This is useful if you want to
		1479	synchronously wait for some requests to finish).
		1480
		1481	See C<nreqs> for an example.
		1482
		1483	=item IO::AIO::poll
		1484
		1485	Waits until some requests have been handled.
		1486
		1487	Returns the number of requests processed, but is otherwise strictly
		1488	equivalent to:
		1489
		1490	IO::AIO::poll_wait, IO::AIO::poll_cb
		1491
		1492	=item IO::AIO::flush
		1493
		1494	Wait till all outstanding AIO requests have been handled.
		1495
		1496	Strictly equivalent to:
		1497
		1498	IO::AIO::poll_wait, IO::AIO::poll_cb
		1499	while IO::AIO::nreqs;
1089		1500
1090	=item IO::AIO::max_poll_reqs $nreqs	1501	=item IO::AIO::max_poll_reqs $nreqs
1091		1502
1092	=item IO::AIO::max_poll_time $seconds	1503	=item IO::AIO::max_poll_time $seconds
1093		1504
…		…
1118	# use a low priority so other tasks have priority	1529	# use a low priority so other tasks have priority
1119	Event->io (fd => IO::AIO::poll_fileno,	1530	Event->io (fd => IO::AIO::poll_fileno,
1120	poll => 'r', nice => 1,	1531	poll => 'r', nice => 1,
1121	cb => &IO::AIO::poll_cb);	1532	cb => &IO::AIO::poll_cb);
1122		1533
1123	=item IO::AIO::poll_wait
1124
1125	If there are any outstanding requests and none of them in the result
1126	phase, wait till the result filehandle becomes ready for reading (simply
1127	does a C<select> on the filehandle. This is useful if you want to
1128	synchronously wait for some requests to finish).
1129
1130	See C<nreqs> for an example.
1131
1132	=item IO::AIO::poll
1133
1134	Waits until some requests have been handled.
1135
1136	Returns the number of requests processed, but is otherwise strictly
1137	equivalent to:
1138
1139	IO::AIO::poll_wait, IO::AIO::poll_cb
1140
1141	=item IO::AIO::flush
1142
1143	Wait till all outstanding AIO requests have been handled.
1144
1145	Strictly equivalent to:
1146
1147	IO::AIO::poll_wait, IO::AIO::poll_cb
1148	while IO::AIO::nreqs;
1149
1150	=back	1534	=back
1151		1535
1152	=head3 CONTROLLING THE NUMBER OF THREADS	1536	=head3 CONTROLLING THE NUMBER OF THREADS
1153		1537
1154	=over	1538	=over
…		…
1187		1571
1188	Under normal circumstances you don't need to call this function.	1572	Under normal circumstances you don't need to call this function.
1189		1573
1190	=item IO::AIO::max_idle $nthreads	1574	=item IO::AIO::max_idle $nthreads
1191		1575
1192	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1576	Limit the number of threads (default: 4) that are allowed to idle
1193	threads that did not get a request to process within 10 seconds). That	1577	(i.e., threads that did not get a request to process within the idle
1194	means if a thread becomes idle while C<$nthreads> other threads are also	1578	timeout (default: 10 seconds). That means if a thread becomes idle while
1195	idle, it will free its resources and exit.	1579	C<$nthreads> other threads are also idle, it will free its resources and
		1580	exit.
1196		1581
1197	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1582	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1198	to allow for extremely high load situations, but want to free resources	1583	to allow for extremely high load situations, but want to free resources
1199	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1584	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1200		1585
1201	The default is probably ok in most situations, especially if thread	1586	The default is probably ok in most situations, especially if thread
1202	creation is fast. If thread creation is very slow on your system you might	1587	creation is fast. If thread creation is very slow on your system you might
1203	want to use larger values.	1588	want to use larger values.
1204		1589
		1590	=item IO::AIO::idle_timeout $seconds
		1591
		1592	Sets the minimum idle timeout (default 10) after which worker threads are
		1593	allowed to exit. SEe C<IO::AIO::max_idle>.
		1594
1205	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1595	=item IO::AIO::max_outstanding $maxreqs
		1596
		1597	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1598	you do queue up more than this number of requests, the next call to
		1599	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1600	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1601	longer exceeded.
		1602
		1603	In other words, this setting does not enforce a queue limit, but can be
		1604	used to make poll functions block if the limit is exceeded.
1206		1605
1207	This is a very bad function to use in interactive programs because it	1606	This is a very bad function to use in interactive programs because it
1208	blocks, and a bad way to reduce concurrency because it is inexact: Better	1607	blocks, and a bad way to reduce concurrency because it is inexact: Better
1209	use an C<aio_group> together with a feed callback.	1608	use an C<aio_group> together with a feed callback.
1210		1609
1211	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1610	It's main use is in scripts without an event loop - when you want to stat
1212	do queue up more than this number of requests, the next call to the	1611	a lot of files, you can write somehting like this:
1213	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1214	function will block until the limit is no longer exceeded.
1215		1612
1216	The default value is very large, so there is no practical limit on the	1613	IO::AIO::max_outstanding 32;
1217	number of outstanding requests.
1218		1614
1219	You can still queue as many requests as you want. Therefore,	1615	for my $path (...) {
1220	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1616	aio_stat $path , ...;
1221	as a stop gap to shield against fatal memory overflow (with large values).	1617	IO::AIO::poll_cb;
		1618	}
		1619
		1620	IO::AIO::flush;
		1621
		1622	The call to C<poll_cb> inside the loop will normally return instantly, but
		1623	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1624	some requests have been handled. This keeps the loop from pushing a large
		1625	number of C<aio_stat> requests onto the queue.
		1626
		1627	The default value for C<max_outstanding> is very large, so there is no
		1628	practical limit on the number of outstanding requests.
1222		1629
1223	=back	1630	=back
1224		1631
1225	=head3 STATISTICAL INFORMATION	1632	=head3 STATISTICAL INFORMATION
1226		1633
…		…
1246	Returns the number of requests currently in the pending state (executed,	1653	Returns the number of requests currently in the pending state (executed,
1247	but not yet processed by poll_cb).	1654	but not yet processed by poll_cb).
1248		1655
1249	=back	1656	=back
1250		1657
		1658	=head3 MISCELLANEOUS FUNCTIONS
		1659
		1660	IO::AIO implements some functions that might be useful, but are not
		1661	asynchronous.
		1662
		1663	=over 4
		1664
		1665	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1666
		1667	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1668	but is blocking (this makes most sense if you know the input data is
		1669	likely cached already and the output filehandle is set to non-blocking
		1670	operations).
		1671
		1672	Returns the number of bytes copied, or C<-1> on error.
		1673
		1674	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1675
		1676	Simply calls the C<posix_fadvise> function (see its
		1677	manpage for details). The following advice constants are
		1678	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1679	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1680	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1681
		1682	On systems that do not implement C<posix_fadvise>, this function returns
		1683	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1684
		1685	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1686
		1687	Simply calls the C<posix_madvise> function (see its
		1688	manpage for details). The following advice constants are
		1689	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1690	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1691
		1692	On systems that do not implement C<posix_madvise>, this function returns
		1693	ENOSYS, otherwise the return value of C<posix_madvise>.
		1694
		1695	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1696
		1697	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1698	$scalar (see its manpage for details). The following protect
		1699	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1700	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1701
		1702	On systems that do not implement C<mprotect>, this function returns
		1703	ENOSYS, otherwise the return value of C<mprotect>.
		1704
		1705	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1706
		1707	Memory-maps a file (or anonymous memory range) and attaches it to the
		1708	given C<$scalar>, which will act like a string scalar.
		1709
		1710	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1711	change the string length, and most read-only operations such as copying it
		1712	or searching it with regexes and so on.
		1713
		1714	Anything else is unsafe and will, at best, result in memory leaks.
		1715
		1716	The memory map associated with the C<$scalar> is automatically removed
		1717	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1718	C<IO::AIO::munmap> functions are called.
		1719
		1720	This calls the C<mmap>(2) function internally. See your system's manual
		1721	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1722
		1723	The C<$length> must be larger than zero and smaller than the actual
		1724	filesize.
		1725
		1726	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1727	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1728
		1729	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1730	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1731	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1732	(which is set to C<MAP_ANON> if your system only provides this
		1733	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1734	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1735	C<IO::AIO::MAP_NONBLOCK>
		1736
		1737	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1738
		1739	C<$offset> is the offset from the start of the file - it generally must be
		1740	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1741
		1742	Example:
		1743
		1744	use Digest::MD5;
		1745	use IO::AIO;
		1746
		1747	open my $fh, "<verybigfile"
		1748	or die "$!";
		1749
		1750	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1751	or die "verybigfile: $!";
		1752
		1753	my $fast_md5 = md5 $data;
		1754
		1755	=item IO::AIO::munmap $scalar
		1756
		1757	Removes a previous mmap and undefines the C<$scalar>.
		1758
		1759	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1760
		1761	Calls the C<munlock> function, undoing the effects of a previous
		1762	C<aio_mlock> call (see its description for details).
		1763
		1764	=item IO::AIO::munlockall
		1765
		1766	Calls the C<munlockall> function.
		1767
		1768	On systems that do not implement C<munlockall>, this function returns
		1769	ENOSYS, otherwise the return value of C<munlockall>.
		1770
		1771	=back
		1772
1251	=cut	1773	=cut
1252		1774
1253	# support function to convert a fd into a perl filehandle
1254	sub _fd2fh {
1255	return undef if $_[0] < 0;
1256
1257	# try to generate nice filehandles
1258	my $sym = "IO::AIO::fd#$_[0]";
1259	local *$sym;
1260
1261	open *$sym, "+<&=$_[0]" # usually works under any unix
1262	or open *$sym, "<&=$_[0]" # cygwin needs this
1263	or open *$sym, ">&=$_[0]" # or this
1264	or return undef;
1265
1266	*$sym
1267	}
1268
1269	min_parallel 8;	1775	min_parallel 8;
1270		1776
1271	END { flush }	1777	END { flush }
1272		1778
1273	1;	1779	1;
1274		1780
		1781	=head1 EVENT LOOP INTEGRATION
		1782
		1783	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1784	automatically into many event loops:
		1785
		1786	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1787	use AnyEvent::AIO;
		1788
		1789	You can also integrate IO::AIO manually into many event loops, here are
		1790	some examples of how to do this:
		1791
		1792	# EV integration
		1793	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1794
		1795	# Event integration
		1796	Event->io (fd => IO::AIO::poll_fileno,
		1797	poll => 'r',
		1798	cb => \&IO::AIO::poll_cb);
		1799
		1800	# Glib/Gtk2 integration
		1801	add_watch Glib::IO IO::AIO::poll_fileno,
		1802	in => sub { IO::AIO::poll_cb; 1 };
		1803
		1804	# Tk integration
		1805	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1806	readable => \&IO::AIO::poll_cb);
		1807
		1808	# Danga::Socket integration
		1809	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1810	\&IO::AIO::poll_cb);
		1811
1275	=head2 FORK BEHAVIOUR	1812	=head2 FORK BEHAVIOUR
1276		1813
1277	This module should do "the right thing" when the process using it forks:	1814	Usage of pthreads in a program changes the semantics of fork
		1815	considerably. Specifically, only async-safe functions can be called after
		1816	fork. Perl doesn't know about this, so in general, you cannot call fork
		1817	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		1818	pthreads, so this applies, but many other extensions and (for inexplicable
		1819	reasons) perl itself often is linked against pthreads, so this limitation
		1820	applies to quite a lot of perls.
1278		1821
1279	Before the fork, IO::AIO enters a quiescent state where no requests	1822	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1280	can be added in other threads and no results will be processed. After	1823	only works in the process that loaded it. Forking is fully supported, but
1281	the fork the parent simply leaves the quiescent state and continues	1824	using IO::AIO in the child is not.
1282	request/result processing, while the child frees the request/result queue
1283	(so that the requests started before the fork will only be handled in the
1284	parent). Threads will be started on demand until the limit set in the
1285	parent process has been reached again.
1286		1825
1287	In short: the parent will, after a short pause, continue as if fork had	1826	You might get around by not I<using> IO::AIO before (or after)
1288	not been called, while the child will act as if IO::AIO has not been used	1827	forking. You could also try to call the L<IO::AIO::reinit> function in the
1289	yet.	1828	child:
		1829
		1830	=over 4
		1831
		1832	=item IO::AIO::reinit
		1833
		1834	Abondons all current requests and I/O threads and simply reinitialises all
		1835	data structures. This is not an operation suppported by any standards, but
		1836	happens to work on GNU/Linux and some newer BSD systems.
		1837
		1838	The only reasonable use for this function is to call it after forking, if
		1839	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1840	the process will result in undefined behaviour. Calling it at any time
		1841	will also result in any undefined (by POSIX) behaviour.
		1842
		1843	=back
1290		1844
1291	=head2 MEMORY USAGE	1845	=head2 MEMORY USAGE
1292		1846
1293	Per-request usage:	1847	Per-request usage:
1294		1848
…		…
1311		1865
1312	Known bugs will be fixed in the next release.	1866	Known bugs will be fixed in the next release.
1313		1867
1314	=head1 SEE ALSO	1868	=head1 SEE ALSO
1315		1869
1316	L<Coro::AIO>.	1870	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1871	more natural syntax.
1317		1872
1318	=head1 AUTHOR	1873	=head1 AUTHOR
1319		1874
1320	Marc Lehmann <schmorp@schmorp.de>	1875	Marc Lehmann <schmorp@schmorp.de>
1321	http://home.schmorp.de/	1876	http://home.schmorp.de/

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