[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs.
Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32	use AnyEvent::AIO;
33
34	# EV integration
35	my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37	# Event integration
38	Event->io (fd => IO::AIO::poll_fileno,
39	poll => 'r',
40	cb => \&IO::AIO::poll_cb);
41
42	# Glib/Gtk2 integration
43	add_watch Glib::IO IO::AIO::poll_fileno,
44	in => sub { IO::AIO::poll_cb; 1 };
45
46	# Tk integration
47	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48	readable => \&IO::AIO::poll_cb);
49
50	# Danga::Socket integration
51	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52	\&IO::AIO::poll_cb);
53
54	=head1 DESCRIPTION	31	=head1 DESCRIPTION
55		32
56	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
57	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>).
58		36
59	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
60	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
61	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
62	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
66	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
67	concurrently.	45	concurrently.
68		46
69	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
70	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
71	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
72	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>
73	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.
74		52
75	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
76	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
77	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
…		…
87	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
88	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
89		67
90	=head2 EXAMPLE	68	=head2 EXAMPLE
91		69
92	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
93	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
94		72
95	use Fcntl;	73	use Fcntl;
96	use Event;	74	use EV;
97	use IO::AIO;	75	use IO::AIO;
98		76
99	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
100	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
101	poll => 'r',
102	cb => \&IO::AIO::poll_cb);
103		79
104	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
105	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
106	my $fh = shift	82	my $fh = shift
107	or die "error while opening: $!";	83	or die "error while opening: $!";
108		84
109	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
110	my $size = -s $fh;	86	my $size = -s $fh;
…		…
119		95
120	# file contents now in $contents	96	# file contents now in $contents
121	print $contents;	97	print $contents;
122		98
123	# exit event loop and program	99	# exit event loop and program
124	Event::unloop;	100	EV::unloop;
125	};	101	};
126	};	102	};
127		103
128	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
129	# check for sockets etc. etc.	105	# check for sockets etc. etc.
130		106
131	# process events as long as there are some:	107	# process events as long as there are some:
132	Event::loop;	108	EV::loop;
133		109
134	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
135		111
136	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
137	directly visible to Perl.	113	directly visible to Perl.
…		…
187		163
188	package IO::AIO;	164	package IO::AIO;
189		165
190	use Carp ();	166	use Carp ();
191		167
192	no warnings;	168	use common::sense;
193	use strict 'vars';
194		169
195	use base 'Exporter';	170	use base 'Exporter';
196		171
197	BEGIN {	172	BEGIN {
198	our $VERSION = '3.19';	173	our $VERSION = '3.9';
199		174
200	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
201	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
202	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
203	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
204	aio_rename aio_link aio_move aio_copy aio_group	179	aio_rename aio_link aio_move aio_copy aio_group
205	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
206	aio_chmod aio_utime aio_truncate);	181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs);
207		184
208	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
209	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
210	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle idle_timeout
211	nreqs nready npending nthreads	188	nreqs nready npending nthreads
212	max_poll_time max_poll_reqs);	189	max_poll_time max_poll_reqs
		190	sendfile fadvise madvise
		191	mmap munmap munlock munlockall);
213		192
214	push @AIO_REQ, qw(aio_busy); # not exported	193	push @AIO_REQ, qw(aio_busy); # not exported
215		194
216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217		196
218	require XSLoader;	197	require XSLoader;
219	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
220	}	199	}
221		200
222	=head1 FUNCTIONS	201	=head1 FUNCTIONS
		202
		203	=head2 QUICK OVERVIEW
		204
		205	This section simply lists the prototypes of the most important functions
		206	for quick reference. See the following sections for function-by-function
		207	documentation.
		208
		209	aio_open $pathname, $flags, $mode, $callback->($fh)
		210	aio_close $fh, $callback->($status)
		211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		214	aio_readahead $fh,$offset,$length, $callback->($retval)
		215	aio_stat $fh_or_path, $callback->($status)
		216	aio_lstat $fh, $callback->($status)
		217	aio_statvfs $fh_or_path, $callback->($statvfs)
		218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		220	aio_truncate $fh_or_path, $offset, $callback->($status)
		221	aio_chmod $fh_or_path, $mode, $callback->($status)
		222	aio_unlink $pathname, $callback->($status)
		223	aio_mknod $path, $mode, $dev, $callback->($status)
		224	aio_link $srcpath, $dstpath, $callback->($status)
		225	aio_symlink $srcpath, $dstpath, $callback->($status)
		226	aio_readlink $path, $callback->($link)
		227	aio_rename $srcpath, $dstpath, $callback->($status)
		228	aio_mkdir $pathname, $mode, $callback->($status)
		229	aio_rmdir $pathname, $callback->($status)
		230	aio_readdir $pathname, $callback->($entries)
		231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		234	aio_load $path, $data, $callback->($status)
		235	aio_copy $srcpath, $dstpath, $callback->($status)
		236	aio_move $srcpath, $dstpath, $callback->($status)
		237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		238	aio_rmtree $path, $callback->($status)
		239	aio_sync $callback->($status)
		240	aio_fsync $fh, $callback->($status)
		241	aio_fdatasync $fh, $callback->($status)
		242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		243	aio_pathsync $path, $callback->($status)
		244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		247	aio_mlockall $flags, $callback->($status)
		248	aio_group $callback->(...)
		249	aio_nop $callback->()
		250
		251	$prev_pri = aioreq_pri [$pri]
		252	aioreq_nice $pri_adjust
		253
		254	IO::AIO::poll_wait
		255	IO::AIO::poll_cb
		256	IO::AIO::poll
		257	IO::AIO::flush
		258	IO::AIO::max_poll_reqs $nreqs
		259	IO::AIO::max_poll_time $seconds
		260	IO::AIO::min_parallel $nthreads
		261	IO::AIO::max_parallel $nthreads
		262	IO::AIO::max_idle $nthreads
		263	IO::AIO::idle_timeout $seconds
		264	IO::AIO::max_outstanding $maxreqs
		265	IO::AIO::nreqs
		266	IO::AIO::nready
		267	IO::AIO::npending
		268
		269	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		270	IO::AIO::fadvise $fh, $offset, $len, $advice
		271	IO::AIO::madvise $scalar, $offset, $length, $advice
		272	IO::AIO::mprotect $scalar, $offset, $length, $protect
		273	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		274	IO::AIO::munlockall
223		275
224	=head2 AIO REQUEST FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
225		277
226	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
227	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
…		…
307	by the umask in effect then the request is being executed, so better never	359	by the umask in effect then the request is being executed, so better never
308	change the umask.	360	change the umask.
309		361
310	Example:	362	Example:
311		363
312	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313	if ($_[0]) {	365	if ($_[0]) {
314	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
315	...	367	...
316	} else {	368	} else {
317	die "open failed: $!\n";	369	die "open failed: $!\n";
318	}	370	}
319	};	371	};
320		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
321		382
322	=item aio_close $fh, $callback->($status)	383	=item aio_close $fh, $callback->($status)
323		384
324	Asynchronously close a file and call the callback with the result	385	Asynchronously close a file and call the callback with the result
325	code.	386	code.
…		…
377	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
378	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
379	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
380	other.	441	other.
381		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<$in_fh>) is a file - the file I/O will then be asynchronous, while
		452	the socket I/O will be non-blocking. Note, however, that you can run into
		453	a trap where C<aio_sendfile> reads some data with readahead, then fails
		454	to write all data, and when the socket is ready the next time, the data
		455	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		456	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		457	much better.
		458
382	This call tries to make use of a native C<sendfile> syscall to provide	459	This call tries to make use of a native C<sendfile> syscall to provide
383	zero-copy operation. For this to work, C<$out_fh> should refer to a	460	zero-copy operation. For this to work, C<$out_fh> should refer to a
384	socket, and C<$in_fh> should refer to mmap'able file.	461	socket, and C<$in_fh> should refer to an mmap'able file.
385		462
386	If the native sendfile call fails or is not implemented, it will be	463	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		464	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
387	emulated, so you can call C<aio_sendfile> on any type of filehandle	465	it will be emulated, so you can call C<aio_sendfile> on any type of
388	regardless of the limitations of the operating system.	466	filehandle regardless of the limitations of the operating system.
389
390	Please note, however, that C<aio_sendfile> can read more bytes from
391	C<$in_fh> than are written, and there is no way to find out how many
392	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
393	provides the number of bytes written to C<$out_fh>. Only if the result
394	value equals C<$length> one can assume that C<$length> bytes have been
395	read.
396		467
397		468
398	=item aio_readahead $fh,$offset,$length, $callback->($retval)	469	=item aio_readahead $fh,$offset,$length, $callback->($retval)
399		470
400	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
…		…
423		494
424	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
425	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
426	unless perl itself is compiled with large file support.	497	unless perl itself is compiled with large file support.
427		498
		499	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		500	following constants and functions (if not implemented, the constants will
		501	be C<0> and the functions will either C<croak> or fall back on traditional
		502	behaviour).
		503
		504	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		505	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		506	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		507
428	Example: Print the length of F</etc/passwd>:	508	Example: Print the length of F</etc/passwd>:
429		509
430	aio_stat "/etc/passwd", sub {	510	aio_stat "/etc/passwd", sub {
431	$_[0] and die "stat failed: $!";	511	$_[0] and die "stat failed: $!";
432	print "size is ", -s _, "\n";	512	print "size is ", -s _, "\n";
433	};	513	};
434		514
435		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
436	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
437		562
438	Works like perl's C<utime> function (including the special case of $atime	563	Works like perl's C<utime> function (including the special case of $atime
439	and $mtime being undef). Fractional times are supported if the underlying	564	and $mtime being undef). Fractional times are supported if the underlying
440	syscalls support them.	565	syscalls support them.
…		…
488		613
489	The only (POSIX-) portable way of calling this function is:	614	The only (POSIX-) portable way of calling this function is:
490		615
491	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	616	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
492		617
		618	See C<aio_stat> for info about some potentially helpful extra constants
		619	and functions.
493		620
494	=item aio_link $srcpath, $dstpath, $callback->($status)	621	=item aio_link $srcpath, $dstpath, $callback->($status)
495		622
496	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
497	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.
…		…
533		660
534	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
535	directory (i.e. opendir + readdir + closedir). The entries will not be	662	directory (i.e. opendir + readdir + closedir). The entries will not be
536	sorted, and will B<NOT> include the C<.> and C<..> entries.	663	sorted, and will B<NOT> include the C<.> and C<..> entries.
537		664
538	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
539	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
540		733
541		734
542	=item aio_load $path, $data, $callback->($status)	735	=item aio_load $path, $data, $callback->($status)
543		736
544	This is a composite request that tries to fully load the given file into	737	This is a composite request that tries to fully load the given file into
…		…
569		762
570	=item aio_copy $srcpath, $dstpath, $callback->($status)	763	=item aio_copy $srcpath, $dstpath, $callback->($status)
571		764
572	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
573	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
574	the C<0> (error) or C<-1> ok.	767	a status of C<0> (ok) or C<-1> (error, see C<$!>).
575		768
576	This is a composite request that creates the destination file with	769	This is a composite request that creates the destination file with
577	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
578	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	771	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
579	uid/gid, in that order.	772	uid/gid, in that order.
…		…
591	my $grp = aio_group $cb;	784	my $grp = aio_group $cb;
592		785
593	aioreq_pri $pri;	786	aioreq_pri $pri;
594	add $grp aio_open $src, O_RDONLY, 0, sub {	787	add $grp aio_open $src, O_RDONLY, 0, sub {
595	if (my $src_fh = $_[0]) {	788	if (my $src_fh = $_[0]) {
596	my @stat = stat $src_fh; # hmm, might bock over nfs?	789	my @stat = stat $src_fh; # hmm, might block over nfs?
597		790
598	aioreq_pri $pri;	791	aioreq_pri $pri;
599	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 {
600	if (my $dst_fh = $_[0]) {	793	if (my $dst_fh = $_[0]) {
601	aioreq_pri $pri;	794	aioreq_pri $pri;
…		…
648		841
649	=item aio_move $srcpath, $dstpath, $callback->($status)	842	=item aio_move $srcpath, $dstpath, $callback->($status)
650		843
651	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
652	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
653	the C<0> (error) or C<-1> ok.	846	a status of C<0> (ok) or C<-1> (error, see C<$!>).
654		847
655	This is a composite request that tries to rename(2) the file first; if	848	This is a composite request that tries to rename(2) the file first; if
656	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if	849	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
657	that is successful, unlinks the C<$srcpath>.	850	that is successful, unlinks the C<$srcpath>.
658		851
…		…
709		902
710	Implementation notes.	903	Implementation notes.
711		904
712	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.
713		906
		907	If readdir returns file type information, then this is used directly to
		908	find directories.
		909
714	After reading the directory, the modification time, size etc. of the	910	Otherwise, after reading the directory, the modification time, size etc.
715	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
716	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
717	entries are directories (if >= 2). Otherwise, no knowledge of the number	913	how many entries are directories (if >= 2). Otherwise, no knowledge of the
718	of subdirectories will be assumed.	914	number of subdirectories will be assumed.
719		915
720	Then entries will be sorted into likely directories (everything without	916	Then entries will be sorted into likely directories a non-initial dot
721	a non-initial dot currently) and likely non-directories (everything	917	currently) and likely non-directories (see C<aio_readdirx>). Then every
722	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,
723	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
724	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
725	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
726	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
727	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.
728		925
729	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
730	rest of the entries is assumed to be non-directories.	927	rest of the entries is assumed to be non-directories.
731		928
732	This only works with certainty on POSIX (= UNIX) filesystems, which	929	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
754	my $now = time;	951	my $now = time;
755	my $hash1 = join ":", (stat _)[0,1,3,7,9];	952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
756		953
757	# read the directory entries	954	# read the directory entries
758	aioreq_pri $pri;	955	aioreq_pri $pri;
759	add $grp aio_readdir $path, sub {	956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
760	my $entries = shift	957	my $entries = shift
761	or return $grp->result ();	958	or return $grp->result ();
762		959
763	# stat the dir another time	960	# stat the dir another time
764	aioreq_pri $pri;	961	aioreq_pri $pri;
…		…
770	# take the slow route if anything looks fishy	967	# take the slow route if anything looks fishy
771	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
772	$ndirs = -1;	969	$ndirs = -1;
773	} else {	970	} else {
774	# if nlink == 2, we are finished	971	# if nlink == 2, we are finished
775	# on non-posix-fs's, we rely on nlink < 2	972	# for non-posix-fs's, we rely on nlink < 2
776	$ndirs = (stat _)[3] - 2	973	$ndirs = (stat _)[3] - 2
777	or return $grp->result ([], $entries);	974	or return $grp->result ([], $entries);
778	}	975	}
779		976
780	# sort into likely dirs and likely nondirs
781	# dirs == files without ".", short entries first
782	$entries = [map $_->[0],
783	sort { $b->[1] cmp $a->[1] }
784	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
785	@$entries];
786
787	my (@dirs, @nondirs);	977	my (@dirs, @nondirs);
788		978
789	my $statgrp = add $grp aio_group sub {	979	my $statgrp = add $grp aio_group sub {
790	$grp->result (\@dirs, \@nondirs);	980	$grp->result (\@dirs, \@nondirs);
791	};	981	};
792		982
793	limit $statgrp $maxreq;	983	limit $statgrp $maxreq;
794	feed $statgrp sub {	984	feed $statgrp sub {
795	return unless @$entries;	985	return unless @$entries;
796	my $entry = pop @$entries;	986	my $entry = shift @$entries;
797		987
798	aioreq_pri $pri;	988	aioreq_pri $pri;
799	add $statgrp aio_stat "$path/$entry/.", sub {	989	add $statgrp aio_stat "$path/$entry/.", sub {
800	if ($_[0] < 0) {	990	if ($_[0] < 0) {
801	push @nondirs, $entry;	991	push @nondirs, $entry;
…		…
895	(E.g. rename). This might not work on all operating systems or have any	1085	(E.g. rename). This might not work on all operating systems or have any
896	specific effect, but usually it makes sure that directory changes get	1086	specific effect, but usually it makes sure that directory changes get
897	written to disc. It works for anything that can be opened for read-only,	1087	written to disc. It works for anything that can be opened for read-only,
898	not just directories.	1088	not just directories.
899		1089
		1090	Future versions of this function might fall back to other methods when
		1091	C<fsync> on the directory fails (such as calling C<sync>).
		1092
900	Passes C<0> when everything went ok, and C<-1> on error.	1093	Passes C<0> when everything went ok, and C<-1> on error.
901		1094
902	=cut	1095	=cut
903		1096
904	sub aio_pathsync($;$) {	1097	sub aio_pathsync($;$) {
…		…
924	};	1117	};
925		1118
926	$grp	1119	$grp
927	}	1120	}
928		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;
		1187
929	=item aio_group $callback->(...)	1188	=item aio_group $callback->(...)
930		1189
931	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
932	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
933	many requests into a single, composite, request with a definite callback	1192	many requests into a single, composite, request with a definite callback
…		…
982	=item cancel $req	1241	=item cancel $req
983		1242
984	Cancels the request, if possible. Has the effect of skipping execution	1243	Cancels the request, if possible. Has the effect of skipping execution
985	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
986	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
987	untouched. That means that requests that currently execute will not be	1246	untouched (with the exception of readdir). That means that requests that
988	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.
989		1249
990	=item cb $req $callback->(...)	1250	=item cb $req $callback->(...)
991		1251
992	Replace (or simply set) the callback registered to the request.	1252	Replace (or simply set) the callback registered to the request.
993		1253
…		…
1066		1326
1067	=item $grp->cancel_subs	1327	=item $grp->cancel_subs
1068		1328
1069	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
1070	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.
		1331
		1332	The group request will finish normally (you cannot add requests to the
		1333	group).
1071		1334
1072	=item $grp->result (...)	1335	=item $grp->result (...)
1073		1336
1074	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
1075	subrequests have finished and set the groups errno to the current value	1338	subrequests have finished and set the groups errno to the current value
…		…
1144	=over 4	1407	=over 4
1145		1408
1146	=item $fileno = IO::AIO::poll_fileno	1409	=item $fileno = IO::AIO::poll_fileno
1147		1410
1148	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
1149	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,
1150	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
1151	to call C<poll_cb> to check the results.	1414	you have to call C<poll_cb> to check the results.
1152		1415
1153	See C<poll_cb> for an example.	1416	See C<poll_cb> for an example.
1154		1417
1155	=item IO::AIO::poll_cb	1418	=item IO::AIO::poll_cb
1156		1419
1157	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
1158	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1421	this regularly. Returns C<0> if all events could be processed (or there
1159	returned earlier for whatever reason. Returns immediately when no events	1422	were no events to process), or C<-1> if it returned earlier for whatever
1160	are outstanding. The amount of events processed depends on the settings of	1423	reason. Returns immediately when no events are outstanding. The amount of
1161	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1424	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1425	C<IO::AIO::max_poll_time>.
1162		1426
1163	If not all requests were processed for whatever reason, the filehandle	1427	If not all requests were processed for whatever reason, the filehandle
1164	will still be ready when C<poll_cb> returns, so normally you don't have to	1428	will still be ready when C<poll_cb> returns, so normally you don't have to
1165	do anything special to have it called later.	1429	do anything special to have it called later.
1166		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.
		1437
1167	Example: Install an Event watcher that automatically calls	1438	Example: Install an Event watcher that automatically calls
1168	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):
1169		1441
1170	Event->io (fd => IO::AIO::poll_fileno,	1442	Event->io (fd => IO::AIO::poll_fileno,
1171	poll => 'r', async => 1,	1443	poll => 'r', async => 1,
1172	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;
1173		1472
1174	=item IO::AIO::max_poll_reqs $nreqs	1473	=item IO::AIO::max_poll_reqs $nreqs
1175		1474
1176	=item IO::AIO::max_poll_time $seconds	1475	=item IO::AIO::max_poll_time $seconds
1177		1476
…		…
1202	# use a low priority so other tasks have priority	1501	# use a low priority so other tasks have priority
1203	Event->io (fd => IO::AIO::poll_fileno,	1502	Event->io (fd => IO::AIO::poll_fileno,
1204	poll => 'r', nice => 1,	1503	poll => 'r', nice => 1,
1205	cb => &IO::AIO::poll_cb);	1504	cb => &IO::AIO::poll_cb);
1206		1505
1207	=item IO::AIO::poll_wait
1208
1209	If there are any outstanding requests and none of them in the result
1210	phase, wait till the result filehandle becomes ready for reading (simply
1211	does a C<select> on the filehandle. This is useful if you want to
1212	synchronously wait for some requests to finish).
1213
1214	See C<nreqs> for an example.
1215
1216	=item IO::AIO::poll
1217
1218	Waits until some requests have been handled.
1219
1220	Returns the number of requests processed, but is otherwise strictly
1221	equivalent to:
1222
1223	IO::AIO::poll_wait, IO::AIO::poll_cb
1224
1225	=item IO::AIO::flush
1226
1227	Wait till all outstanding AIO requests have been handled.
1228
1229	Strictly equivalent to:
1230
1231	IO::AIO::poll_wait, IO::AIO::poll_cb
1232	while IO::AIO::nreqs;
1233
1234	=back	1506	=back
1235		1507
1236	=head3 CONTROLLING THE NUMBER OF THREADS	1508	=head3 CONTROLLING THE NUMBER OF THREADS
1237		1509
1238	=over	1510	=over
…		…
1271		1543
1272	Under normal circumstances you don't need to call this function.	1544	Under normal circumstances you don't need to call this function.
1273		1545
1274	=item IO::AIO::max_idle $nthreads	1546	=item IO::AIO::max_idle $nthreads
1275		1547
1276	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1548	Limit the number of threads (default: 4) that are allowed to idle
1277	threads that did not get a request to process within 10 seconds). That	1549	(i.e., threads that did not get a request to process within the idle
1278	means if a thread becomes idle while C<$nthreads> other threads are also	1550	timeout (default: 10 seconds). That means if a thread becomes idle while
1279	idle, it will free its resources and exit.	1551	C<$nthreads> other threads are also idle, it will free its resources and
		1552	exit.
1280		1553
1281	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)
1282	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
1283	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1556	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1284		1557
1285	The default is probably ok in most situations, especially if thread	1558	The default is probably ok in most situations, especially if thread
1286	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
1287	want to use larger values.	1560	want to use larger values.
1288		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
1289	=item 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.
1290		1577
1291	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
1292	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
1293	use an C<aio_group> together with a feed callback.	1580	use an C<aio_group> together with a feed callback.
1294		1581
1295	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
1296	do queue up more than this number of requests, the next call to the	1583	a lot of files, you can write somehting like this:
1297	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1298	function will block until the limit is no longer exceeded.
1299		1584
1300	The default value is very large, so there is no practical limit on the	1585	IO::AIO::max_outstanding 32;
1301	number of outstanding requests.
1302		1586
1303	You can still queue as many requests as you want. Therefore,	1587	for my $path (...) {
1304	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1588	aio_stat $path , ...;
1305	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.
1306		1601
1307	=back	1602	=back
1308		1603
1309	=head3 STATISTICAL INFORMATION	1604	=head3 STATISTICAL INFORMATION
1310		1605
…		…
1330	Returns the number of requests currently in the pending state (executed,	1625	Returns the number of requests currently in the pending state (executed,
1331	but not yet processed by poll_cb).	1626	but not yet processed by poll_cb).
1332		1627
1333	=back	1628	=back
1334		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
1335	=cut	1745	=cut
1336		1746
1337	min_parallel 8;	1747	min_parallel 8;
1338		1748
1339	END { flush }	1749	END { flush }
1340		1750
1341	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);
1342		1783
1343	=head2 FORK BEHAVIOUR	1784	=head2 FORK BEHAVIOUR
1344		1785
1345	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:
1346		1787

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs. Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs.
Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC