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Revision 1.86 by root, Sat Oct 28 23:32:29 2006 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) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
30	# AnyEvent integration
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33
34	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',
37	cb => \&IO::AIO::poll_cb);
38
39	# Glib/Gtk2 integration
40	add_watch Glib::IO IO::AIO::poll_fileno,
41	in => sub { IO::AIO::poll_cb; 1 };
42
43	# Tk integration
44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
45	readable => \&IO::AIO::poll_cb);
46
47	# Danga::Socket integration
48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
49	\&IO::AIO::poll_cb);
50
51	=head1 DESCRIPTION	31	=head1 DESCRIPTION
52		32
53	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
54	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>).
55		36
56	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
57	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
58	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
59	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
61	etc.), but can also be used to easily do operations in parallel that are	42	etc.), but can also be used to easily do operations in parallel that are
62	normally done sequentially, e.g. stat'ing many files, which is much faster	43	normally done sequentially, e.g. stat'ing many files, which is much faster
63	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
64	concurrently.	45	concurrently.
65		46
66	While this works on all types of file descriptors (for example sockets),	47	While most of this works on all types of file descriptors (for
67	using these functions on file descriptors that support nonblocking	48	example sockets), using these functions on file descriptors that
68	operation (again, sockets, pipes etc.) is very inefficient. Use an event	49	support nonblocking operation (again, sockets, pipes etc.) is
69	loop for that (such as the L<Event|Event> module): IO::AIO will naturally	50	very inefficient. Use an event loop for that (such as the L<EV>
70	fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
71		52
72	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
73	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
74	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
75	to perl. In the future, this module might make use of the native aio	56	to perl. In the future, this module might make use of the native aio
…		…
77	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
78	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
79	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
80	using threads anyway.	61	using threads anyway.
81		62
82	Although the module will work with in the presence of other (Perl-)	63	Although the module will work in the presence of other (Perl-) threads,
83	threads, it is currently not reentrant in any way, so use appropriate	64	it is currently not reentrant in any way, so use appropriate locking
84	locking yourself, always call C<poll_cb> from within the same thread, or	65	yourself, always call C<poll_cb> from within the same thread, or never
85	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
86		67
87	=head2 EXAMPLE	68	=head2 EXAMPLE
88		69
89	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
90	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
91		72
92	use Fcntl;	73	use Fcntl;
93	use Event;	74	use EV;
94	use IO::AIO;	75	use IO::AIO;
95		76
96	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
97	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
98	poll => 'r',
99	cb => \&IO::AIO::poll_cb);
100		79
101	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
102	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
103	my $fh = $_[0]	82	my $fh = shift
104	or die "error while opening: $!";	83	or die "error while opening: $!";
105		84
106	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
107	my $size = -s $fh;	86	my $size = -s $fh;
108		87
…		…
116		95
117	# file contents now in $contents	96	# file contents now in $contents
118	print $contents;	97	print $contents;
119		98
120	# exit event loop and program	99	# exit event loop and program
121	Event::unloop;	100	EV::unloop;
122	};	101	};
123	};	102	};
124		103
125	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
126	# check for sockets etc. etc.	105	# check for sockets etc. etc.
127		106
128	# process events as long as there are some:	107	# process events as long as there are some:
129	Event::loop;	108	EV::loop;
130		109
131	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
132		111
133	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
134	directly visible to Perl.	113	directly visible to Perl.
…		…
176	Request has reached the end of its lifetime and holds no resources anymore	155	Request has reached the end of its lifetime and holds no resources anymore
177	(except possibly for the Perl object, but its connection to the actual	156	(except possibly for the Perl object, but its connection to the actual
178	aio request is severed and calling its methods will either do nothing or	157	aio request is severed and calling its methods will either do nothing or
179	result in a runtime error).	158	result in a runtime error).
180		159
		160	=back
		161
181	=cut	162	=cut
182		163
183	package IO::AIO;	164	package IO::AIO;
184		165
185	no warnings;	166	use Carp ();
186	use strict 'vars';	167
		168	use common::sense;
187		169
188	use base 'Exporter';	170	use base 'Exporter';
189		171
190	BEGIN {	172	BEGIN {
191	our $VERSION = '2.1';	173	our $VERSION = '3.9';
192		174
193	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
194	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
195	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
196	aio_copy aio_group aio_nop aio_mknod);	178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		179	aio_rename aio_link aio_move aio_copy aio_group
		180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs);
		184
197	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
198	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
199	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle idle_timeout
200	nreqs nready npending nthreads	188	nreqs nready npending nthreads
201	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
202		194
203	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
204		196
205	require XSLoader;	197	require XSLoader;
206	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
207	}	199	}
208		200
209	=head1 FUNCTIONS	201	=head1 FUNCTIONS
210		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, $length = undef
		274	IO::AIO::munlockall
		275
211	=head2 AIO FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
212		277
213	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
214	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
215	and they all accept an additional (and optional) C<$callback> argument	280	and they all accept an additional (and optional) C<$callback> argument
216	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
217	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
218	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
219	syscall has been executed asynchronously.	284	syscall has been executed asynchronously.
220		285
221	All functions expecting a filehandle keep a copy of the filehandle	286	All functions expecting a filehandle keep a copy of the filehandle
222	internally until the request has finished.	287	internally until the request has finished.
223		288
224	All requests return objects of type L<IO::AIO::REQ> that allow further	289	All functions return request objects of type L<IO::AIO::REQ> that allow
225	manipulation of those requests while they are in-flight.	290	further manipulation of those requests while they are in-flight.
226		291
227	The pathnames you pass to these routines I<must> be absolute and	292	The pathnames you pass to these routines I<must> be absolute and
228	encoded in byte form. The reason for the former is that at the time the	293	encoded as octets. The reason for the former is that at the time the
229	request is being executed, the current working directory could have	294	request is being executed, the current working directory could have
230	changed. Alternatively, you can make sure that you never change the	295	changed. Alternatively, you can make sure that you never change the
231	current working directory.	296	current working directory anywhere in the program and then use relative
		297	paths.
232		298
233	To encode pathnames to byte form, either make sure you either: a)	299	To encode pathnames as octets, either make sure you either: a) always pass
234	always pass in filenames you got from outside (command line, readdir	300	in filenames you got from outside (command line, readdir etc.) without
235	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	301	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
236	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
237	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)
238	use something else.	304	use something else to ensure your scalar has the correct contents.
		305
		306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		307	handles correctly whether it is set or not.
239		308
240	=over 4	309	=over 4
241		310
242	=item $prev_pri = aioreq_pri [$pri]	311	=item $prev_pri = aioreq_pri [$pri]
243		312
…		…
263	aio_read $_[0], ..., sub {	332	aio_read $_[0], ..., sub {
264	...	333	...
265	};	334	};
266	};	335	};
267		336
		337
268	=item aioreq_nice $pri_adjust	338	=item aioreq_nice $pri_adjust
269		339
270	Similar to C<aioreq_pri>, but subtracts the given value from the current	340	Similar to C<aioreq_pri>, but subtracts the given value from the current
271	priority, so effects are cumulative.	341	priority, so the effect is cumulative.
		342
272		343
273	=item aio_open $pathname, $flags, $mode, $callback->($fh)	344	=item aio_open $pathname, $flags, $mode, $callback->($fh)
274		345
275	Asynchronously open or create a file and call the callback with a newly	346	Asynchronously open or create a file and call the callback with a newly
276	created filehandle for the file.	347	created filehandle for the file.
…		…
282	list. They are the same as used by C<sysopen>.	353	list. They are the same as used by C<sysopen>.
283		354
284	Likewise, C<$mode> specifies the mode of the newly created file, if it	355	Likewise, C<$mode> specifies the mode of the newly created file, if it
285	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	356	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
286	except that it is mandatory (i.e. use C<0> if you don't create new files,	357	except that it is mandatory (i.e. use C<0> if you don't create new files,
287	and C<0666> or C<0777> if you do).	358	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		359	by the umask in effect then the request is being executed, so better never
		360	change the umask.
288		361
289	Example:	362	Example:
290		363
291	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
292	if ($_[0]) {	365	if ($_[0]) {
293	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
294	...	367	...
295	} else {	368	} else {
296	die "open failed: $!\n";	369	die "open failed: $!\n";
297	}	370	}
298	};	371	};
299		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
		382
300	=item aio_close $fh, $callback->($status)	383	=item aio_close $fh, $callback->($status)
301		384
302	Asynchronously close a file and call the callback with the result	385	Asynchronously close a file and call the callback with the result
303	code. I<WARNING:> although accepted, you should not pass in a perl	386	code.
304	filehandle here, as perl will likely close the file descriptor another
305	time when the filehandle is destroyed. Normally, you can safely call perls
306	C<close> or just let filehandles go out of scope.
307		387
308	This is supposed to be a bug in the API, so that might change. It's	388	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
309	therefore best to avoid this function.	389	closing the file descriptor associated with the filehandle itself.
		390
		391	Therefore, C<aio_close> will not close the filehandle - instead it will
		392	use dup2 to overwrite the file descriptor with the write-end of a pipe
		393	(the pipe fd will be created on demand and will be cached).
		394
		395	Or in other words: the file descriptor will be closed, but it will not be
		396	free for reuse until the perl filehandle is closed.
		397
		398	=cut
310		399
311	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	400	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
312		401
313	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	402	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
314		403
315	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
316	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<$dataoffset>
317	callback without the actual number of bytes read (or -1 on error, just	406	and calls the callback without the actual number of bytes read (or -1 on
318	like the syscall).	407	error, just like the syscall).
		408
		409	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		410	offset plus the actual number of bytes read.
		411
		412	If C<$offset> is undefined, then the current file descriptor offset will
		413	be used (and updated), otherwise the file descriptor offset will not be
		414	changed by these calls.
		415
		416	If C<$length> is undefined in C<aio_write>, use the remaining length of
		417	C<$data>.
		418
		419	If C<$dataoffset> is less than zero, it will be counted from the end of
		420	C<$data>.
319		421
320	The C<$data> scalar I<MUST NOT> be modified in any way while the request	422	The C<$data> scalar I<MUST NOT> be modified in any way while the request
321	is outstanding. Modifying it can result in segfaults or WW3 (if the	423	is outstanding. Modifying it can result in segfaults or World War III (if
322	necessary/optional hardware is installed).	424	the necessary/optional hardware is installed).
323		425
324	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	426	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
325	offset C<0> within the scalar:	427	offset C<0> within the scalar:
326		428
327	aio_read $fh, 7, 15, $buffer, 0, sub {	429	aio_read $fh, 7, 15, $buffer, 0, sub {
328	$_[0] > 0 or die "read error: $!";	430	$_[0] > 0 or die "read error: $!";
329	print "read $_[0] bytes: <$buffer>\n";	431	print "read $_[0] bytes: <$buffer>\n";
330	};	432	};
		433
331		434
332	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	435	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
333		436
334	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	437	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
335	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
336	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
337	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
338	other.	441	other.
339		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<$in_fh>) is a file - the file I/O will then be asynchronous, while
		452	the socket I/O will be non-blocking. Note, however, that you can run into
		453	a trap where C<aio_sendfile> reads some data with readahead, then fails
		454	to write all data, and when the socket is ready the next time, the data
		455	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		456	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		457	much better.
		458
340	This call tries to make use of a native C<sendfile> syscall to provide	459	This call tries to make use of a native C<sendfile> syscall to provide
341	zero-copy operation. For this to work, C<$out_fh> should refer to a	460	zero-copy operation. For this to work, C<$out_fh> should refer to a
342	socket, and C<$in_fh> should refer to mmap'able file.	461	socket, and C<$in_fh> should refer to an mmap'able file.
343		462
344	If the native sendfile call fails or is not implemented, it will be	463	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		464	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
345	emulated, so you can call C<aio_sendfile> on any type of filehandle	465	it will be emulated, so you can call C<aio_sendfile> on any type of
346	regardless of the limitations of the operating system.	466	filehandle regardless of the limitations of the operating system.
347		467
348	Please note, however, that C<aio_sendfile> can read more bytes from
349	C<$in_fh> than are written, and there is no way to find out how many
350	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
351	provides the number of bytes written to C<$out_fh>. Only if the result
352	value equals C<$length> one can assume that C<$length> bytes have been
353	read.
354		468
355	=item aio_readahead $fh,$offset,$length, $callback->($retval)	469	=item aio_readahead $fh,$offset,$length, $callback->($retval)
356		470
357	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
358	subsequent reads from that file will not block on disk I/O. The C<$offset>	472	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
364	file. The current file offset of the file is left unchanged.	478	file. The current file offset of the file is left unchanged.
365		479
366	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	480	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
367	emulated by simply reading the data, which would have a similar effect.	481	emulated by simply reading the data, which would have a similar effect.
368		482
		483
369	=item aio_stat $fh_or_path, $callback->($status)	484	=item aio_stat $fh_or_path, $callback->($status)
370		485
371	=item aio_lstat $fh, $callback->($status)	486	=item aio_lstat $fh, $callback->($status)
372		487
373	Works like perl's C<stat> or C<lstat> in void context. The callback will	488	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
378	for an explanation.	493	for an explanation.
379		494
380	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
381	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
382	unless perl itself is compiled with large file support.	497	unless perl itself is compiled with large file support.
		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>.
383		507
384	Example: Print the length of F</etc/passwd>:	508	Example: Print the length of F</etc/passwd>:
385		509
386	aio_stat "/etc/passwd", sub {	510	aio_stat "/etc/passwd", sub {
387	$_[0] and die "stat failed: $!";	511	$_[0] and die "stat failed: $!";
388	print "size is ", -s _, "\n";	512	print "size is ", -s _, "\n";
389	};	513	};
390		514
		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
		561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		562
		563	Works like perl's C<utime> function (including the special case of $atime
		564	and $mtime being undef). Fractional times are supported if the underlying
		565	syscalls support them.
		566
		567	When called with a pathname, uses utimes(2) if available, otherwise
		568	utime(2). If called on a file descriptor, uses futimes(2) if available,
		569	otherwise returns ENOSYS, so this is not portable.
		570
		571	Examples:
		572
		573	# set atime and mtime to current time (basically touch(1)):
		574	aio_utime "path", undef, undef;
		575	# set atime to current time and mtime to beginning of the epoch:
		576	aio_utime "path", time, undef; # undef==0
		577
		578
		579	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		580
		581	Works like perl's C<chown> function, except that C<undef> for either $uid
		582	or $gid is being interpreted as "do not change" (but -1 can also be used).
		583
		584	Examples:
		585
		586	# same as "chown root path" in the shell:
		587	aio_chown "path", 0, -1;
		588	# same as above:
		589	aio_chown "path", 0, undef;
		590
		591
		592	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		593
		594	Works like truncate(2) or ftruncate(2).
		595
		596
		597	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		598
		599	Works like perl's C<chmod> function.
		600
		601
391	=item aio_unlink $pathname, $callback->($status)	602	=item aio_unlink $pathname, $callback->($status)
392		603
393	Asynchronously unlink (delete) a file and call the callback with the	604	Asynchronously unlink (delete) a file and call the callback with the
394	result code.	605	result code.
395		606
		607
396	=item aio_mknod $path, $mode, $dev, $callback->($status)	608	=item aio_mknod $path, $mode, $dev, $callback->($status)
397		609
398	[EXPERIMENTAL]	610	[EXPERIMENTAL]
399		611
400	Asynchronously create a device node (or fifo). See mknod(2).	612	Asynchronously create a device node (or fifo). See mknod(2).
401		613
402	The only (POSIX-) portable way of calling this function is:	614	The only (POSIX-) portable way of calling this function is:
403		615
404	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	616	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		617
		618	See C<aio_stat> for info about some potentially helpful extra constants
		619	and functions.
405		620
406	=item aio_link $srcpath, $dstpath, $callback->($status)	621	=item aio_link $srcpath, $dstpath, $callback->($status)
407		622
408	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
409	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.
410		625
		626
411	=item aio_symlink $srcpath, $dstpath, $callback->($status)	627	=item aio_symlink $srcpath, $dstpath, $callback->($status)
412		628
413	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	629	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
414	the path C<$dstpath> and call the callback with the result code.	630	the path C<$dstpath> and call the callback with the result code.
415		631
		632
		633	=item aio_readlink $path, $callback->($link)
		634
		635	Asynchronously read the symlink specified by C<$path> and pass it to
		636	the callback. If an error occurs, nothing or undef gets passed to the
		637	callback.
		638
		639
416	=item aio_rename $srcpath, $dstpath, $callback->($status)	640	=item aio_rename $srcpath, $dstpath, $callback->($status)
417		641
418	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	642	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
419	rename(2) and call the callback with the result code.	643	rename(2) and call the callback with the result code.
420		644
		645
		646	=item aio_mkdir $pathname, $mode, $callback->($status)
		647
		648	Asynchronously mkdir (create) a directory and call the callback with
		649	the result code. C<$mode> will be modified by the umask at the time the
		650	request is executed, so do not change your umask.
		651
		652
421	=item aio_rmdir $pathname, $callback->($status)	653	=item aio_rmdir $pathname, $callback->($status)
422		654
423	Asynchronously rmdir (delete) a directory and call the callback with the	655	Asynchronously rmdir (delete) a directory and call the callback with the
424	result code.	656	result code.
		657
425		658
426	=item aio_readdir $pathname, $callback->($entries)	659	=item aio_readdir $pathname, $callback->($entries)
427		660
428	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
429	directory (i.e. opendir + readdir + closedir). The entries will not be	662	directory (i.e. opendir + readdir + closedir). The entries will not be
430	sorted, and will B<NOT> include the C<.> and C<..> entries.	663	sorted, and will B<NOT> include the C<.> and C<..> entries.
431		664
432	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
433	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
		733
		734
		735	=item aio_load $path, $data, $callback->($status)
		736
		737	This is a composite request that tries to fully load the given file into
		738	memory. Status is the same as with aio_read.
		739
		740	=cut
		741
		742	sub aio_load($$;$) {
		743	my ($path, undef, $cb) = @_;
		744	my $data = \$_[1];
		745
		746	my $pri = aioreq_pri;
		747	my $grp = aio_group $cb;
		748
		749	aioreq_pri $pri;
		750	add $grp aio_open $path, O_RDONLY, 0, sub {
		751	my $fh = shift
		752	or return $grp->result (-1);
		753
		754	aioreq_pri $pri;
		755	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		756	$grp->result ($_[0]);
		757	};
		758	};
		759
		760	$grp
		761	}
434		762
435	=item aio_copy $srcpath, $dstpath, $callback->($status)	763	=item aio_copy $srcpath, $dstpath, $callback->($status)
436		764
437	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
438	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
439	the C<0> (error) or C<-1> ok.	767	a status of C<0> (ok) or C<-1> (error, see C<$!>).
440		768
441	This is a composite request that it creates the destination file with	769	This is a composite request that creates the destination file with
442	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
443	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	771	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
444	uid/gid, in that order.	772	uid/gid, in that order.
445		773
446	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
…		…
456	my $grp = aio_group $cb;	784	my $grp = aio_group $cb;
457		785
458	aioreq_pri $pri;	786	aioreq_pri $pri;
459	add $grp aio_open $src, O_RDONLY, 0, sub {	787	add $grp aio_open $src, O_RDONLY, 0, sub {
460	if (my $src_fh = $_[0]) {	788	if (my $src_fh = $_[0]) {
461	my @stat = stat $src_fh;	789	my @stat = stat $src_fh; # hmm, might block over nfs?
462		790
463	aioreq_pri $pri;	791	aioreq_pri $pri;
464	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 {
465	if (my $dst_fh = $_[0]) {	793	if (my $dst_fh = $_[0]) {
466	aioreq_pri $pri;	794	aioreq_pri $pri;
467	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	795	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
468	if ($_[0] == $stat[7]) {	796	if ($_[0] == $stat[7]) {
469	$grp->result (0);	797	$grp->result (0);
470	close $src_fh;	798	close $src_fh;
471		799
472	# those should not normally block. should. should.	800	my $ch = sub {
		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;
		806	add $grp aio_close $dst_fh;
		807	}
		808	};
		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;
473	utime $stat[8], $stat[9], $dst;	815	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
474	chmod $stat[2] & 07777, $dst_fh;	816	} else {
475	chown $stat[4], $stat[5], $dst_fh;	817	$ch->();
		818	}
476	close $dst_fh;	819	};
477	} else {	820	} else {
478	$grp->result (-1);	821	$grp->result (-1);
479	close $src_fh;	822	close $src_fh;
480	close $dst_fh;	823	close $dst_fh;
481		824
…		…
498		841
499	=item aio_move $srcpath, $dstpath, $callback->($status)	842	=item aio_move $srcpath, $dstpath, $callback->($status)
500		843
501	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
502	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
503	the C<0> (error) or C<-1> ok.	846	a status of C<0> (ok) or C<-1> (error, see C<$!>).
504		847
505	This is a composite request that tries to rename(2) the file first. If	848	This is a composite request that tries to rename(2) the file first; if
506	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	849	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
507	that is successful, unlinking the C<$srcpath>.	850	that is successful, unlinks the C<$srcpath>.
508		851
509	=cut	852	=cut
510		853
511	sub aio_move($$;$) {	854	sub aio_move($$;$) {
512	my ($src, $dst, $cb) = @_;	855	my ($src, $dst, $cb) = @_;
…		…
559		902
560	Implementation notes.	903	Implementation notes.
561		904
562	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.
563		906
		907	If readdir returns file type information, then this is used directly to
		908	find directories.
		909
564	After reading the directory, the modification time, size etc. of the	910	Otherwise, after reading the directory, the modification time, size etc.
565	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
566	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
567	entries are directories (if >= 2). Otherwise, no knowledge of the number	913	how many entries are directories (if >= 2). Otherwise, no knowledge of the
568	of subdirectories will be assumed.	914	number of subdirectories will be assumed.
569		915
570	Then entries will be sorted into likely directories (everything without	916	Then entries will be sorted into likely directories a non-initial dot
571	a non-initial dot currently) and likely non-directories (everything	917	currently) and likely non-directories (see C<aio_readdirx>). Then every
572	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,
573	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
574	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
575	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
576	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
577	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.
578		925
579	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
580	rest of the entries is assumed to be non-directories.	927	rest of the entries is assumed to be non-directories.
581		928
582	This only works with certainty on POSIX (= UNIX) filesystems, which	929	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
586	as those tend to return 0 or 1 as link counts, which disables the	933	as those tend to return 0 or 1 as link counts, which disables the
587	directory counting heuristic.	934	directory counting heuristic.
588		935
589	=cut	936	=cut
590		937
591	sub aio_scandir($$$) {	938	sub aio_scandir($$;$) {
592	my ($path, $maxreq, $cb) = @_;	939	my ($path, $maxreq, $cb) = @_;
593		940
594	my $pri = aioreq_pri;	941	my $pri = aioreq_pri;
595		942
596	my $grp = aio_group $cb;	943	my $grp = aio_group $cb;
…		…
604	my $now = time;	951	my $now = time;
605	my $hash1 = join ":", (stat _)[0,1,3,7,9];	952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
606		953
607	# read the directory entries	954	# read the directory entries
608	aioreq_pri $pri;	955	aioreq_pri $pri;
609	add $grp aio_readdir $path, sub {	956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
610	my $entries = shift	957	my $entries = shift
611	or return $grp->result ();	958	or return $grp->result ();
612		959
613	# stat the dir another time	960	# stat the dir another time
614	aioreq_pri $pri;	961	aioreq_pri $pri;
…		…
620	# take the slow route if anything looks fishy	967	# take the slow route if anything looks fishy
621	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
622	$ndirs = -1;	969	$ndirs = -1;
623	} else {	970	} else {
624	# if nlink == 2, we are finished	971	# if nlink == 2, we are finished
625	# on non-posix-fs's, we rely on nlink < 2	972	# for non-posix-fs's, we rely on nlink < 2
626	$ndirs = (stat _)[3] - 2	973	$ndirs = (stat _)[3] - 2
627	or return $grp->result ([], $entries);	974	or return $grp->result ([], $entries);
628	}	975	}
629		976
630	# sort into likely dirs and likely nondirs
631	# dirs == files without ".", short entries first
632	$entries = [map $_->[0],
633	sort { $b->[1] cmp $a->[1] }
634	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
635	@$entries];
636
637	my (@dirs, @nondirs);	977	my (@dirs, @nondirs);
638		978
639	my $statgrp = add $grp aio_group sub {	979	my $statgrp = add $grp aio_group sub {
640	$grp->result (\@dirs, \@nondirs);	980	$grp->result (\@dirs, \@nondirs);
641	};	981	};
642		982
643	limit $statgrp $maxreq;	983	limit $statgrp $maxreq;
644	feed $statgrp sub {	984	feed $statgrp sub {
645	return unless @$entries;	985	return unless @$entries;
646	my $entry = pop @$entries;	986	my $entry = shift @$entries;
647		987
648	aioreq_pri $pri;	988	aioreq_pri $pri;
649	add $statgrp aio_stat "$path/$entry/.", sub {	989	add $statgrp aio_stat "$path/$entry/.", sub {
650	if ($_[0] < 0) {	990	if ($_[0] < 0) {
651	push @nondirs, $entry;	991	push @nondirs, $entry;
…		…
672	};	1012	};
673		1013
674	$grp	1014	$grp
675	}	1015	}
676		1016
		1017	=item aio_rmtree $path, $callback->($status)
		1018
		1019	Delete a directory tree starting (and including) C<$path>, return the
		1020	status of the final C<rmdir> only. This is a composite request that
		1021	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		1022	everything else.
		1023
		1024	=cut
		1025
		1026	sub aio_rmtree;
		1027	sub aio_rmtree($;$) {
		1028	my ($path, $cb) = @_;
		1029
		1030	my $pri = aioreq_pri;
		1031	my $grp = aio_group $cb;
		1032
		1033	aioreq_pri $pri;
		1034	add $grp aio_scandir $path, 0, sub {
		1035	my ($dirs, $nondirs) = @_;
		1036
		1037	my $dirgrp = aio_group sub {
		1038	add $grp aio_rmdir $path, sub {
		1039	$grp->result ($_[0]);
		1040	};
		1041	};
		1042
		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;
		1047	};
		1048
		1049	$grp
		1050	}
		1051
		1052	=item aio_sync $callback->($status)
		1053
		1054	Asynchronously call sync and call the callback when finished.
		1055
677	=item aio_fsync $fh, $callback->($status)	1056	=item aio_fsync $fh, $callback->($status)
678		1057
679	Asynchronously call fsync on the given filehandle and call the callback	1058	Asynchronously call fsync on the given filehandle and call the callback
680	with the fsync result code.	1059	with the fsync result code.
681		1060
…		…
684	Asynchronously call fdatasync on the given filehandle and call the	1063	Asynchronously call fdatasync on the given filehandle and call the
685	callback with the fdatasync result code.	1064	callback with the fdatasync result code.
686		1065
687	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
688	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;
689		1187
690	=item aio_group $callback->(...)	1188	=item aio_group $callback->(...)
691		1189
692	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
693	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
…		…
743	=item cancel $req	1241	=item cancel $req
744		1242
745	Cancels the request, if possible. Has the effect of skipping execution	1243	Cancels the request, if possible. Has the effect of skipping execution
746	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
747	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
748	untouched. That means that requests that currently execute will not be	1246	untouched (with the exception of readdir). That means that requests that
749	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.
750		1249
751	=item cb $req $callback->(...)	1250	=item cb $req $callback->(...)
752		1251
753	Replace (or simply set) the callback registered to the request.	1252	Replace (or simply set) the callback registered to the request.
754		1253
…		…
805	Their lifetime, simplified, looks like this: when they are empty, they	1304	Their lifetime, simplified, looks like this: when they are empty, they
806	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
807	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
808	exist.	1307	exist.
809		1308
810	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
811	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
812	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
813	itself finish.	1312	further requests to the group. And only when all those requests have
		1313	finished will the the group itself finish.
814		1314
815	=over 4	1315	=over 4
816		1316
817	=item add $grp ...	1317	=item add $grp ...
818		1318
…		…
827	=item $grp->cancel_subs	1327	=item $grp->cancel_subs
828		1328
829	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
830	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.
831		1331
		1332	The group request will finish normally (you cannot add requests to the
		1333	group).
		1334
832	=item $grp->result (...)	1335	=item $grp->result (...)
833		1336
834	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
835	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
836	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,
837	no argument will be passed and errno is zero.	1340	no argument will be passed and errno is zero.
838		1341
839	=item $grp->errno ([$errno])	1342	=item $grp->errno ([$errno])
840		1343
…		…
851	=item feed $grp $callback->($grp)	1354	=item feed $grp $callback->($grp)
852		1355
853	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
854	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,
855	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,
856	this might starve other requests for a potentially long time. For	1359	this might starve other requests for a potentially long time. For example,
857	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,
858	requests, delaying any later requests for a long time.	1361	delaying any later requests for a long time.
859		1362
860	To avoid this, and allow incremental generation of requests, you can	1363	To avoid this, and allow incremental generation of requests, you can
861	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
862	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>,
863	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
…		…
867	not impose any limits).	1370	not impose any limits).
868		1371
869	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
870	automatically removed from the group.	1373	automatically removed from the group.
871		1374
872	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.
873		1377
874	Example:	1378	Example:
875		1379
876	# 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:
877		1381
…		…
889	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
890	the group contains less than this many requests.	1394	the group contains less than this many requests.
891		1395
892	Setting the limit to C<0> will pause the feeding process.	1396	Setting the limit to C<0> will pause the feeding process.
893		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
894	=back	1401	=back
895		1402
896	=head2 SUPPORT FUNCTIONS	1403	=head2 SUPPORT FUNCTIONS
897		1404
898	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1405	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
900	=over 4	1407	=over 4
901		1408
902	=item $fileno = IO::AIO::poll_fileno	1409	=item $fileno = IO::AIO::poll_fileno
903		1410
904	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
905	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,
906	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
907	to call C<poll_cb> to check the results.	1414	you have to call C<poll_cb> to check the results.
908		1415
909	See C<poll_cb> for an example.	1416	See C<poll_cb> for an example.
910		1417
911	=item IO::AIO::poll_cb	1418	=item IO::AIO::poll_cb
912		1419
913	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
914	regularly. Returns the number of events processed. Returns immediately	1421	this regularly. Returns C<0> if all events could be processed (or there
915	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
916	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>.
917		1426
918	If not all requests were processed for whatever reason, the filehandle	1427	If not all requests were processed for whatever reason, the filehandle
919	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.
920		1437
921	Example: Install an Event watcher that automatically calls	1438	Example: Install an Event watcher that automatically calls
922	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):
923		1441
924	Event->io (fd => IO::AIO::poll_fileno,	1442	Event->io (fd => IO::AIO::poll_fileno,
925	poll => 'r', async => 1,	1443	poll => 'r', async => 1,
926	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;
927		1472
928	=item IO::AIO::max_poll_reqs $nreqs	1473	=item IO::AIO::max_poll_reqs $nreqs
929		1474
930	=item IO::AIO::max_poll_time $seconds	1475	=item IO::AIO::max_poll_time $seconds
931		1476
…		…
933	that are being processed by C<IO::AIO::poll_cb> in one call, respectively	1478	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
934	the maximum amount of time (default C<0>, meaning infinity) spent in	1479	the maximum amount of time (default C<0>, meaning infinity) spent in
935	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount	1480	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
936	of time C<poll_cb> is allowed to use).	1481	of time C<poll_cb> is allowed to use).
937		1482
		1483	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1484	syscall per request processed, which is not normally a problem unless your
		1485	callbacks are really really fast or your OS is really really slow (I am
		1486	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1487
938	Setting these is useful if you want to ensure some level of	1488	Setting these is useful if you want to ensure some level of
939	interactiveness when perl is not fast enough to process all requests in	1489	interactiveness when perl is not fast enough to process all requests in
940	time.	1490	time.
941		1491
942	For interactive programs, values such as C<0.01> to C<0.1> should be fine.	1492	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
943		1493
944	Example: Install an Event watcher that automatically calls	1494	Example: Install an Event watcher that automatically calls
945	IO::AIO::poll_some with low priority, to ensure that other parts of the	1495	IO::AIO::poll_cb with low priority, to ensure that other parts of the
946	program get the CPU sometimes even under high AIO load.	1496	program get the CPU sometimes even under high AIO load.
947		1497
948	# try not to spend much more than 0.1s in poll_cb	1498	# try not to spend much more than 0.1s in poll_cb
949	IO::AIO::max_poll_time 0.1;	1499	IO::AIO::max_poll_time 0.1;
950		1500
951	# use a low priority so other tasks have priority	1501	# use a low priority so other tasks have priority
952	Event->io (fd => IO::AIO::poll_fileno,	1502	Event->io (fd => IO::AIO::poll_fileno,
953	poll => 'r', nice => 1,	1503	poll => 'r', nice => 1,
954	cb => &IO::AIO::poll_cb);	1504	cb => &IO::AIO::poll_cb);
955		1505
956	=item IO::AIO::poll_wait	1506	=back
957
958	Wait till the result filehandle becomes ready for reading (simply does a
959	C<select> on the filehandle. This is useful if you want to synchronously
960	wait for some requests to finish).
961
962	See C<nreqs> for an example.
963
964	=item IO::AIO::poll
965
966	Waits until some requests have been handled.
967
968	Strictly equivalent to:
969
970	IO::AIO::poll_wait, IO::AIO::poll_cb
971	if IO::AIO::nreqs;
972
973	=item IO::AIO::flush
974
975	Wait till all outstanding AIO requests have been handled.
976
977	Strictly equivalent to:
978
979	IO::AIO::poll_wait, IO::AIO::poll_cb
980	while IO::AIO::nreqs;
981		1507
982	=head3 CONTROLLING THE NUMBER OF THREADS	1508	=head3 CONTROLLING THE NUMBER OF THREADS
		1509
		1510	=over
983		1511
984	=item IO::AIO::min_parallel $nthreads	1512	=item IO::AIO::min_parallel $nthreads
985		1513
986	Set the minimum number of AIO threads to C<$nthreads>. The current	1514	Set the minimum number of AIO threads to C<$nthreads>. The current
987	default is C<8>, which means eight asynchronous operations can execute	1515	default is C<8>, which means eight asynchronous operations can execute
…		…
1015		1543
1016	Under normal circumstances you don't need to call this function.	1544	Under normal circumstances you don't need to call this function.
1017		1545
1018	=item IO::AIO::max_idle $nthreads	1546	=item IO::AIO::max_idle $nthreads
1019		1547
1020	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1548	Limit the number of threads (default: 4) that are allowed to idle
1021	threads that did not get a request to process within 10 seconds). That	1549	(i.e., threads that did not get a request to process within the idle
1022	means if a thread becomes idle while C<$nthreads> other threads are also	1550	timeout (default: 10 seconds). That means if a thread becomes idle while
1023	idle, it will free its resources and exit.	1551	C<$nthreads> other threads are also idle, it will free its resources and
		1552	exit.
1024		1553
1025	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)
1026	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
1027	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1556	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1028		1557
1029	The default is probably ok in most situations, especially if thread	1558	The default is probably ok in most situations, especially if thread
1030	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
1031	want to use larger values.	1560	want to use larger values.
1032		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
1033	=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.
1034		1577
1035	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
1036	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
1037	use an C<aio_group> together with a feed callback.	1580	use an C<aio_group> together with a feed callback.
1038		1581
1039	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
1040	to queue up more than this number of requests, the next call to the	1583	a lot of files, you can write somehting like this:
1041	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1042	function will block until the limit is no longer exceeded.
1043		1584
1044	The default value is very large, so there is no practical limit on the	1585	IO::AIO::max_outstanding 32;
1045	number of outstanding requests.
1046		1586
1047	You can still queue as many requests as you want. Therefore,	1587	for my $path (...) {
1048	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1588	aio_stat $path , ...;
1049	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.
		1601
		1602	=back
1050		1603
1051	=head3 STATISTICAL INFORMATION	1604	=head3 STATISTICAL INFORMATION
		1605
		1606	=over
1052		1607
1053	=item IO::AIO::nreqs	1608	=item IO::AIO::nreqs
1054		1609
1055	Returns the number of requests currently in the ready, execute or pending	1610	Returns the number of requests currently in the ready, execute or pending
1056	states (i.e. for which their callback has not been invoked yet).	1611	states (i.e. for which their callback has not been invoked yet).
…		…
1070	Returns the number of requests currently in the pending state (executed,	1625	Returns the number of requests currently in the pending state (executed,
1071	but not yet processed by poll_cb).	1626	but not yet processed by poll_cb).
1072		1627
1073	=back	1628	=back
1074		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
1075	=cut	1745	=cut
1076		1746
1077	# support function to convert a fd into a perl filehandle
1078	sub _fd2fh {
1079	return undef if $_[0] < 0;
1080
1081	# try to generate nice filehandles
1082	my $sym = "IO::AIO::fd#$_[0]";
1083	local *$sym;
1084
1085	open *$sym, "+<&=$_[0]" # usually works under any unix
1086	or open *$sym, "<&=$_[0]" # cygwin needs this
1087	or open *$sym, ">&=$_[0]" # or this
1088	or return undef;
1089
1090	*$sym
1091	}
1092
1093	min_parallel 8;	1747	min_parallel 8;
1094		1748
1095	END {	1749	END { flush }
1096	min_parallel 1;
1097	flush;
1098	};
1099		1750
1100	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);
1101		1783
1102	=head2 FORK BEHAVIOUR	1784	=head2 FORK BEHAVIOUR
1103		1785
1104	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:
1105		1787
…		…
1123	bytes of memory. In addition, stat requests need a stat buffer (possibly	1805	bytes of memory. In addition, stat requests need a stat buffer (possibly
1124	a few hundred bytes), readdir requires a result buffer and so on. Perl	1806	a few hundred bytes), readdir requires a result buffer and so on. Perl
1125	scalars and other data passed into aio requests will also be locked and	1807	scalars and other data passed into aio requests will also be locked and
1126	will consume memory till the request has entered the done state.	1808	will consume memory till the request has entered the done state.
1127		1809
1128	This is now awfully much, so queuing lots of requests is not usually a	1810	This is not awfully much, so queuing lots of requests is not usually a
1129	problem.	1811	problem.
1130		1812
1131	Per-thread usage:	1813	Per-thread usage:
1132		1814
1133	In the execution phase, some aio requests require more memory for	1815	In the execution phase, some aio requests require more memory for
…		…
1138		1820
1139	Known bugs will be fixed in the next release.	1821	Known bugs will be fixed in the next release.
1140		1822
1141	=head1 SEE ALSO	1823	=head1 SEE ALSO
1142		1824
1143	L<Coro::AIO>.	1825	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1826	more natural syntax.
1144		1827
1145	=head1 AUTHOR	1828	=head1 AUTHOR
1146		1829
1147	Marc Lehmann <schmorp@schmorp.de>	1830	Marc Lehmann <schmorp@schmorp.de>
1148	http://home.schmorp.de/	1831	http://home.schmorp.de/

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