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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.170 by root, Sat Jan 2 14:11:32 2010 UTC vs.
Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
25	my $req = aio_unlink "/tmp/file", sub { };	25	my $req = aio_unlink "/tmp/file", sub { };
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
31	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32	use AnyEvent::AIO;
33
34	# EV integration
35	my $aio_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		30
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. It is implemented as an interface to C<libeio>	34	operating system supports. It is implemented as an interface to C<libeio>
…		…
99		76
100	# register the IO::AIO callback with EV	77	# register the IO::AIO callback with EV
101	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102		79
103	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105	my $fh = shift	82	my $fh = shift
106	or die "error while opening: $!";	83	or die "error while opening: $!";
107		84
108	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
109	my $size = -s $fh;	86	my $size = -s $fh;
…		…
191	use common::sense;	168	use common::sense;
192		169
193	use base 'Exporter';	170	use base 'Exporter';
194		171
195	BEGIN {	172	BEGIN {
196	our $VERSION = '3.31';	173	our $VERSION = '4.0';
197		174
198	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
199	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
200	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
201	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
		179	aio_pathsync aio_readahead
202	aio_rename aio_link aio_move aio_copy aio_group	180	aio_rename aio_link aio_move aio_copy aio_group
203	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
204	aio_chmod aio_utime aio_truncate	182	aio_chmod aio_utime aio_truncate
205	aio_msync aio_mtouch);	183	aio_msync aio_mtouch aio_mlock aio_mlockall
		184	aio_statvfs
		185	aio_wd);
206		186
207	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209	min_parallel max_parallel max_idle	189	min_parallel max_parallel max_idle idle_timeout
210	nreqs nready npending nthreads	190	nreqs nready npending nthreads
211	max_poll_time max_poll_reqs	191	max_poll_time max_poll_reqs
212	sendfile fadvise);	192	sendfile fadvise madvise
		193	mmap munmap munlock munlockall);
213		194
214	push @AIO_REQ, qw(aio_busy); # not exported	195	push @AIO_REQ, qw(aio_busy); # not exported
215		196
216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	197	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217		198
218	require XSLoader;	199	require XSLoader;
219	XSLoader::load ("IO::AIO", $VERSION);	200	XSLoader::load ("IO::AIO", $VERSION);
220	}	201	}
221		202
222	=head1 FUNCTIONS	203	=head1 FUNCTIONS
		204
		205	=head2 QUICK OVERVIEW
		206
		207	This section simply lists the prototypes of the most important functions
		208	for quick reference. See the following sections for function-by-function
		209	documentation.
		210
		211	aio_wd $pathname, $callback->($wd)
		212	aio_open $pathname, $flags, $mode, $callback->($fh)
		213	aio_close $fh, $callback->($status)
		214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		217	aio_readahead $fh,$offset,$length, $callback->($retval)
		218	aio_stat $fh_or_path, $callback->($status)
		219	aio_lstat $fh, $callback->($status)
		220	aio_statvfs $fh_or_path, $callback->($statvfs)
		221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		223	aio_truncate $fh_or_path, $offset, $callback->($status)
		224	aio_chmod $fh_or_path, $mode, $callback->($status)
		225	aio_unlink $pathname, $callback->($status)
		226	aio_mknod $pathname, $mode, $dev, $callback->($status)
		227	aio_link $srcpath, $dstpath, $callback->($status)
		228	aio_symlink $srcpath, $dstpath, $callback->($status)
		229	aio_readlink $pathname, $callback->($link)
		230	aio_realpath $pathname, $callback->($link)
		231	aio_rename $srcpath, $dstpath, $callback->($status)
		232	aio_mkdir $pathname, $mode, $callback->($status)
		233	aio_rmdir $pathname, $callback->($status)
		234	aio_readdir $pathname, $callback->($entries)
		235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		238	aio_load $pathname, $data, $callback->($status)
		239	aio_copy $srcpath, $dstpath, $callback->($status)
		240	aio_move $srcpath, $dstpath, $callback->($status)
		241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
		242	aio_rmtree $pathname, $callback->($status)
		243	aio_sync $callback->($status)
		244	aio_syncfs $fh, $callback->($status)
		245	aio_fsync $fh, $callback->($status)
		246	aio_fdatasync $fh, $callback->($status)
		247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		248	aio_pathsync $pathname, $callback->($status)
		249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		252	aio_mlockall $flags, $callback->($status)
		253	aio_group $callback->(...)
		254	aio_nop $callback->()
		255
		256	$prev_pri = aioreq_pri [$pri]
		257	aioreq_nice $pri_adjust
		258
		259	IO::AIO::poll_wait
		260	IO::AIO::poll_cb
		261	IO::AIO::poll
		262	IO::AIO::flush
		263	IO::AIO::max_poll_reqs $nreqs
		264	IO::AIO::max_poll_time $seconds
		265	IO::AIO::min_parallel $nthreads
		266	IO::AIO::max_parallel $nthreads
		267	IO::AIO::max_idle $nthreads
		268	IO::AIO::idle_timeout $seconds
		269	IO::AIO::max_outstanding $maxreqs
		270	IO::AIO::nreqs
		271	IO::AIO::nready
		272	IO::AIO::npending
		273
		274	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		275	IO::AIO::fadvise $fh, $offset, $len, $advice
		276	IO::AIO::madvise $scalar, $offset, $length, $advice
		277	IO::AIO::mprotect $scalar, $offset, $length, $protect
		278	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		279	IO::AIO::munlockall
223		280
224	=head2 AIO REQUEST FUNCTIONS	281	=head2 AIO REQUEST FUNCTIONS
225		282
226	All the C<aio_*> calls are more or less thin wrappers around the syscall	283	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,	284	with the same name (sans C<aio_>). The arguments are similar or identical,
…		…
235	internally until the request has finished.	292	internally until the request has finished.
236		293
237	All functions return request objects of type L<IO::AIO::REQ> that allow	294	All functions return request objects of type L<IO::AIO::REQ> that allow
238	further manipulation of those requests while they are in-flight.	295	further manipulation of those requests while they are in-flight.
239		296
240	The pathnames you pass to these routines I<must> be absolute and	297	The pathnames you pass to these routines I<should> be absolute. The
241	encoded as octets. The reason for the former is that at the time the	298	reason for this is that at the time the request is being executed, the
242	request is being executed, the current working directory could have	299	current working directory could have changed. Alternatively, you can make
243	changed. Alternatively, you can make sure that you never change the	300	sure that you never change the current working directory anywhere in
244	current working directory anywhere in the program and then use relative	301	the program and then use relative paths. Lastly, you can take advantage
245	paths.	302	of IO::AIOs working directory abstraction - see the description of the
		303	C<IO::AIO::WD> class later in this document.
246		304
247	To encode pathnames as octets, either make sure you either: a) always pass	305	To encode pathnames as octets, either make sure you either: a) always pass
248	in filenames you got from outside (command line, readdir etc.) without	306	in filenames you got from outside (command line, readdir etc.) without
249	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	307	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
250	your pathnames to the locale (or other) encoding in effect in the user	308	your pathnames to the locale (or other) encoding in effect in the user
…		…
307	by the umask in effect then the request is being executed, so better never	365	by the umask in effect then the request is being executed, so better never
308	change the umask.	366	change the umask.
309		367
310	Example:	368	Example:
311		369
312	aio_open "/etc/passwd", O_RDONLY, 0, sub {	370	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313	if ($_[0]) {	371	if ($_[0]) {
314	print "open successful, fh is $_[0]\n";	372	print "open successful, fh is $_[0]\n";
315	...	373	...
316	} else {	374	} else {
317	die "open failed: $!\n";	375	die "open failed: $!\n";
318	}	376	}
319	};	377	};
320		378
		379	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		380	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		381	following POSIX and non-POSIX constants are available (missing ones on
		382	your system are, as usual, C<0>):
		383
		384	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		385	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		386	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		387
321		388
322	=item aio_close $fh, $callback->($status)	389	=item aio_close $fh, $callback->($status)
323		390
324	Asynchronously close a file and call the callback with the result	391	Asynchronously close a file and call the callback with the result
325	code.	392	code.
…		…
375		442
376	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	443	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377	reading at byte offset C<$in_offset>, and starts writing at the current	444	reading at byte offset C<$in_offset>, and starts writing at the current
378	file offset of C<$out_fh>. Because of that, it is not safe to issue more	445	file offset of C<$out_fh>. Because of that, it is not safe to issue more
379	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	446	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380	other.	447	other. The same C<$in_fh> works fine though, as this function does not
		448	move or use the file offset of C<$in_fh>.
381		449
		450	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		451	are written, and there is no way to find out how many more bytes have been
		452	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		453	number of bytes written to C<$out_fh>. Only if the result value equals
		454	C<$length> one can assume that C<$length> bytes have been read.
		455
		456	Unlike with other C<aio_> functions, it makes a lot of sense to use
		457	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		458	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		459	the socket I/O will be non-blocking. Note, however, that you can run
		460	into a trap where C<aio_sendfile> reads some data with readahead, then
		461	fails to write all data, and when the socket is ready the next time, the
		462	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		463	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		464	resource usage.
		465
382	This call tries to make use of a native C<sendfile> syscall to provide	466	This call tries to make use of a native C<sendfile>-like syscall to
383	zero-copy operation. For this to work, C<$out_fh> should refer to a	467	provide zero-copy operation. For this to work, C<$out_fh> should refer to
384	socket, and C<$in_fh> should refer to mmap'able file.	468	a socket, and C<$in_fh> should refer to an mmap'able file.
385		469
386	If a native sendfile cannot be found or it fails with C<ENOSYS>,	470	If a native sendfile cannot be found or it fails with C<ENOSYS>,
387	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	471	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388	it will be emulated, so you can call C<aio_sendfile> on any type of	472	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389	filehandle regardless of the limitations of the operating system.	473	type of filehandle regardless of the limitations of the operating system.
390		474
391	Please note, however, that C<aio_sendfile> can read more bytes from	475	As native sendfile syscalls (as practically any non-POSIX interface hacked
392	C<$in_fh> than are written, and there is no way to find out how many	476	together in a hurry to improve benchmark numbers) tend to be rather buggy
393	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	477	on many systems, this implementation tries to work around some known bugs
394	provides the number of bytes written to C<$out_fh>. Only if the result	478	in Linux and FreeBSD kernels (probably others, too), but that might fail,
395	value equals C<$length> one can assume that C<$length> bytes have been	479	so you really really should check the return value of C<aio_sendfile> -
396	read.	480	fewre bytes than expected might have been transferred.
397		481
398		482
399	=item aio_readahead $fh,$offset,$length, $callback->($retval)	483	=item aio_readahead $fh,$offset,$length, $callback->($retval)
400		484
401	C<aio_readahead> populates the page cache with data from a file so that	485	C<aio_readahead> populates the page cache with data from a file so that
…		…
424		508
425	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	509	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
426	error when stat'ing a large file, the results will be silently truncated	510	error when stat'ing a large file, the results will be silently truncated
427	unless perl itself is compiled with large file support.	511	unless perl itself is compiled with large file support.
428		512
		513	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		514	following constants and functions (if not implemented, the constants will
		515	be C<0> and the functions will either C<croak> or fall back on traditional
		516	behaviour).
		517
		518	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		519	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		520	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		521
429	Example: Print the length of F</etc/passwd>:	522	Example: Print the length of F</etc/passwd>:
430		523
431	aio_stat "/etc/passwd", sub {	524	aio_stat "/etc/passwd", sub {
432	$_[0] and die "stat failed: $!";	525	$_[0] and die "stat failed: $!";
433	print "size is ", -s _, "\n";	526	print "size is ", -s _, "\n";
434	};	527	};
435		528
436		529
		530	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		531
		532	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		533	whether a file handle or path was passed.
		534
		535	On success, the callback is passed a hash reference with the following
		536	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		537	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		538	is passed.
		539
		540	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		541	C<ST_NOSUID>.
		542
		543	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		544	their correct value when available, or to C<0> on systems that do
		545	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		546	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		547	C<ST_NODIRATIME> and C<ST_RELATIME>.
		548
		549	Example: stat C</wd> and dump out the data if successful.
		550
		551	aio_statvfs "/wd", sub {
		552	my $f = $_[0]
		553	or die "statvfs: $!";
		554
		555	use Data::Dumper;
		556	say Dumper $f;
		557	};
		558
		559	# result:
		560	{
		561	bsize => 1024,
		562	bfree => 4333064312,
		563	blocks => 10253828096,
		564	files => 2050765568,
		565	flag => 4096,
		566	favail => 2042092649,
		567	bavail => 4333064312,
		568	ffree => 2042092649,
		569	namemax => 255,
		570	frsize => 1024,
		571	fsid => 1810
		572	}
		573
		574
437	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	575	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
438		576
439	Works like perl's C<utime> function (including the special case of $atime	577	Works like perl's C<utime> function (including the special case of $atime
440	and $mtime being undef). Fractional times are supported if the underlying	578	and $mtime being undef). Fractional times are supported if the underlying
441	syscalls support them.	579	syscalls support them.
…		…
479		617
480	Asynchronously unlink (delete) a file and call the callback with the	618	Asynchronously unlink (delete) a file and call the callback with the
481	result code.	619	result code.
482		620
483		621
484	=item aio_mknod $path, $mode, $dev, $callback->($status)	622	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
485		623
486	[EXPERIMENTAL]	624	[EXPERIMENTAL]
487		625
488	Asynchronously create a device node (or fifo). See mknod(2).	626	Asynchronously create a device node (or fifo). See mknod(2).
489		627
490	The only (POSIX-) portable way of calling this function is:	628	The only (POSIX-) portable way of calling this function is:
491		629
492	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	630	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
493		631
		632	See C<aio_stat> for info about some potentially helpful extra constants
		633	and functions.
494		634
495	=item aio_link $srcpath, $dstpath, $callback->($status)	635	=item aio_link $srcpath, $dstpath, $callback->($status)
496		636
497	Asynchronously create a new link to the existing object at C<$srcpath> at	637	Asynchronously create a new link to the existing object at C<$srcpath> at
498	the path C<$dstpath> and call the callback with the result code.	638	the path C<$dstpath> and call the callback with the result code.
…		…
502		642
503	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	643	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
504	the path C<$dstpath> and call the callback with the result code.	644	the path C<$dstpath> and call the callback with the result code.
505		645
506		646
507	=item aio_readlink $path, $callback->($link)	647	=item aio_readlink $pathname, $callback->($link)
508		648
509	Asynchronously read the symlink specified by C<$path> and pass it to	649	Asynchronously read the symlink specified by C<$path> and pass it to
510	the callback. If an error occurs, nothing or undef gets passed to the	650	the callback. If an error occurs, nothing or undef gets passed to the
511	callback.	651	callback.
512		652
513		653
		654	=item aio_realpath $pathname, $callback->($path)
		655
		656	Asynchronously make the path absolute and resolve any symlinks in
		657	C<$path>. The resulting path only consists of directories (Same as
		658	L<Cwd::realpath>).
		659
		660	This request can be used to get the absolute path of the current working
		661	directory by passing it a path of F<.> (a single dot).
		662
		663
514	=item aio_rename $srcpath, $dstpath, $callback->($status)	664	=item aio_rename $srcpath, $dstpath, $callback->($status)
515		665
516	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	666	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
517	rename(2) and call the callback with the result code.	667	rename(2) and call the callback with the result code.
518		668
…		…
540	array-ref with the filenames.	690	array-ref with the filenames.
541		691
542		692
543	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	693	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
544		694
545	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	695	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
546	behaviour and output format. In case of an error, C<$entries> will be	696	tune behaviour and output format. In case of an error, C<$entries> will be
547	C<undef>.	697	C<undef>.
548		698
549	The flags are a combination of the following constants, ORed together (the	699	The flags are a combination of the following constants, ORed together (the
550	flags will also be passed to the callback, possibly modified):	700	flags will also be passed to the callback, possibly modified):
551		701
552	=over 4	702	=over 4
553		703
554	=item IO::AIO::READDIR_DENTS	704	=item IO::AIO::READDIR_DENTS
555		705
556	When this flag is off, then the callback gets an arrayref with of names	706	When this flag is off, then the callback gets an arrayref consisting of
557	only (as with C<aio_readdir>), otherwise it gets an arrayref with	707	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
558	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	708	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
559	entry in more detail.	709	entry in more detail.
560		710
561	C<$name> is the name of the entry.	711	C<$name> is the name of the entry.
562		712
…		…
575	systems that do not deliver the inode information.	725	systems that do not deliver the inode information.
576		726
577	=item IO::AIO::READDIR_DIRS_FIRST	727	=item IO::AIO::READDIR_DIRS_FIRST
578		728
579	When this flag is set, then the names will be returned in an order where	729	When this flag is set, then the names will be returned in an order where
580	likely directories come first. This is useful when you need to quickly	730	likely directories come first, in optimal stat order. This is useful when
581	find directories, or you want to find all directories while avoiding to	731	you need to quickly find directories, or you want to find all directories
582	stat() each entry.	732	while avoiding to stat() each entry.
583		733
584	If the system returns type information in readdir, then this is used	734	If the system returns type information in readdir, then this is used
585	to find directories directly. Otherwise, likely directories are files	735	to find directories directly. Otherwise, likely directories are names
586	beginning with ".", or otherwise files with no dots, of which files with	736	beginning with ".", or otherwise names with no dots, of which names with
587	short names are tried first.	737	short names are tried first.
588		738
589	=item IO::AIO::READDIR_STAT_ORDER	739	=item IO::AIO::READDIR_STAT_ORDER
590		740
591	When this flag is set, then the names will be returned in an order	741	When this flag is set, then the names will be returned in an order
…		…
598		748
599	=item IO::AIO::READDIR_FOUND_UNKNOWN	749	=item IO::AIO::READDIR_FOUND_UNKNOWN
600		750
601	This flag should not be set when calling C<aio_readdirx>. Instead, it	751	This flag should not be set when calling C<aio_readdirx>. Instead, it
602	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	752	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
603	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	753	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
604	C<$type>'s are known, which can be used to speed up some algorithms.	754	C<$type>'s are known, which can be used to speed up some algorithms.
605		755
606	=back	756	=back
607		757
608		758
609	=item aio_load $path, $data, $callback->($status)	759	=item aio_load $pathname, $data, $callback->($status)
610		760
611	This is a composite request that tries to fully load the given file into	761	This is a composite request that tries to fully load the given file into
612	memory. Status is the same as with aio_read.	762	memory. Status is the same as with aio_read.
613		763
614	=cut	764	=cut
…		…
736	if ($_[0] && $! == EXDEV) {	886	if ($_[0] && $! == EXDEV) {
737	aioreq_pri $pri;	887	aioreq_pri $pri;
738	add $grp aio_copy $src, $dst, sub {	888	add $grp aio_copy $src, $dst, sub {
739	$grp->result ($_[0]);	889	$grp->result ($_[0]);
740		890
741	if (!$_[0]) {	891	unless ($_[0]) {
742	aioreq_pri $pri;	892	aioreq_pri $pri;
743	add $grp aio_unlink $src;	893	add $grp aio_unlink $src;
744	}	894	}
745	};	895	};
746	} else {	896	} else {
…		…
749	};	899	};
750		900
751	$grp	901	$grp
752	}	902	}
753		903
754	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	904	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
755		905
756	Scans a directory (similar to C<aio_readdir>) but additionally tries to	906	Scans a directory (similar to C<aio_readdir>) but additionally tries to
757	efficiently separate the entries of directory C<$path> into two sets of	907	efficiently separate the entries of directory C<$path> into two sets of
758	names, directories you can recurse into (directories), and ones you cannot	908	names, directories you can recurse into (directories), and ones you cannot
759	recurse into (everything else, including symlinks to directories).	909	recurse into (everything else, including symlinks to directories).
…		…
790	Then entries will be sorted into likely directories a non-initial dot	940	Then entries will be sorted into likely directories a non-initial dot
791	currently) and likely non-directories (see C<aio_readdirx>). Then every	941	currently) and likely non-directories (see C<aio_readdirx>). Then every
792	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	942	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
793	in order of their inode numbers. If that succeeds, it assumes that the	943	in order of their inode numbers. If that succeeds, it assumes that the
794	entry is a directory or a symlink to directory (which will be checked	944	entry is a directory or a symlink to directory (which will be checked
795	seperately). This is often faster than stat'ing the entry itself because	945	separately). This is often faster than stat'ing the entry itself because
796	filesystems might detect the type of the entry without reading the inode	946	filesystems might detect the type of the entry without reading the inode
797	data (e.g. ext2fs filetype feature), even on systems that cannot return	947	data (e.g. ext2fs filetype feature), even on systems that cannot return
798	the filetype information on readdir.	948	the filetype information on readdir.
799		949
800	If the known number of directories (link count - 2) has been reached, the	950	If the known number of directories (link count - 2) has been reached, the
…		…
886	};	1036	};
887		1037
888	$grp	1038	$grp
889	}	1039	}
890		1040
891	=item aio_rmtree $path, $callback->($status)	1041	=item aio_rmtree $pathname, $callback->($status)
892		1042
893	Delete a directory tree starting (and including) C<$path>, return the	1043	Delete a directory tree starting (and including) C<$path>, return the
894	status of the final C<rmdir> only. This is a composite request that	1044	status of the final C<rmdir> only. This is a composite request that
895	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1045	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
896	everything else.	1046	everything else.
…		…
938	callback with the fdatasync result code.	1088	callback with the fdatasync result code.
939		1089
940	If this call isn't available because your OS lacks it or it couldn't be	1090	If this call isn't available because your OS lacks it or it couldn't be
941	detected, it will be emulated by calling C<fsync> instead.	1091	detected, it will be emulated by calling C<fsync> instead.
942		1092
		1093	=item aio_syncfs $fh, $callback->($status)
		1094
		1095	Asynchronously call the syncfs syscall to sync the filesystem associated
		1096	to the given filehandle and call the callback with the syncfs result
		1097	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1098	errno to C<ENOSYS> nevertheless.
		1099
943	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1100	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
944		1101
945	Sync the data portion of the file specified by C<$offset> and C<$length>	1102	Sync the data portion of the file specified by C<$offset> and C<$length>
946	to disk (but NOT the metadata), by calling the Linux-specific	1103	to disk (but NOT the metadata), by calling the Linux-specific
947	sync_file_range call. If sync_file_range is not available or it returns	1104	sync_file_range call. If sync_file_range is not available or it returns
…		…
950	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1107	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
951	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1108	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
952	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1109	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
953	manpage for details.	1110	manpage for details.
954		1111
955	=item aio_pathsync $path, $callback->($status)	1112	=item aio_pathsync $pathname, $callback->($status)
956		1113
957	This request tries to open, fsync and close the given path. This is a	1114	This request tries to open, fsync and close the given path. This is a
958	composite request intended to sync directories after directory operations	1115	composite request intended to sync directories after directory operations
959	(E.g. rename). This might not work on all operating systems or have any	1116	(E.g. rename). This might not work on all operating systems or have any
960	specific effect, but usually it makes sure that directory changes get	1117	specific effect, but usually it makes sure that directory changes get
…		…
994	}	1151	}
995		1152
996	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1153	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
997		1154
998	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1155	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
999	scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note	1156	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1157	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1000	that the scalar must only be modified in-place while an aio operation is	1158	scalar must only be modified in-place while an aio operation is pending on
1001	pending on it).	1159	it).
1002		1160
1003	It calls the C<msync> function of your OS, if available, with the memory	1161	It calls the C<msync> function of your OS, if available, with the memory
1004	area starting at C<$offset> in the string and ending C<$length> bytes	1162	area starting at C<$offset> in the string and ending C<$length> bytes
1005	later. If C<$length> is negative, counts from the end, and if C<$length>	1163	later. If C<$length> is negative, counts from the end, and if C<$length>
1006	is C<undef>, then it goes till the end of the string. The flags can be	1164	is C<undef>, then it goes till the end of the string. The flags can be
…		…
1017	as for C<aio_msync>, above, except for flags, which must be either	1175	as for C<aio_msync>, above, except for flags, which must be either
1018	C<0> (which reads all pages and ensures they are instantiated) or	1176	C<0> (which reads all pages and ensures they are instantiated) or
1019	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1177	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1020	writing an octet from it, which dirties the page).	1178	writing an octet from it, which dirties the page).
1021		1179
		1180	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1181
		1182	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1183	scalars.
		1184
		1185	It reads in all the pages of the underlying storage into memory (if any)
		1186	and locks them, so they are not getting swapped/paged out or removed.
		1187
		1188	If C<$length> is undefined, then the scalar will be locked till the end.
		1189
		1190	On systems that do not implement C<mlock>, this function returns C<-1>
		1191	and sets errno to C<ENOSYS>.
		1192
		1193	Note that the corresponding C<munlock> is synchronous and is
		1194	documented under L<MISCELLANEOUS FUNCTIONS>.
		1195
		1196	Example: open a file, mmap and mlock it - both will be undone when
		1197	C<$data> gets destroyed.
		1198
		1199	open my $fh, "<", $path or die "$path: $!";
		1200	my $data;
		1201	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1202	aio_mlock $data; # mlock in background
		1203
		1204	=item aio_mlockall $flags, $callback->($status)
		1205
		1206	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1207	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1208
		1209	On systems that do not implement C<mlockall>, this function returns C<-1>
		1210	and sets errno to C<ENOSYS>.
		1211
		1212	Note that the corresponding C<munlockall> is synchronous and is
		1213	documented under L<MISCELLANEOUS FUNCTIONS>.
		1214
		1215	Example: asynchronously lock all current and future pages into memory.
		1216
		1217	aio_mlockall IO::AIO::MCL_FUTURE;
		1218
1022	=item aio_group $callback->(...)	1219	=item aio_group $callback->(...)
1023		1220
1024	This is a very special aio request: Instead of doing something, it is a	1221	This is a very special aio request: Instead of doing something, it is a
1025	container for other aio requests, which is useful if you want to bundle	1222	container for other aio requests, which is useful if you want to bundle
1026	many requests into a single, composite, request with a definite callback	1223	many requests into a single, composite, request with a definite callback
…		…
1062	like sleep and file handle readable/writable, the overhead this creates is	1259	like sleep and file handle readable/writable, the overhead this creates is
1063	immense (it blocks a thread for a long time) so do not use this function	1260	immense (it blocks a thread for a long time) so do not use this function
1064	except to put your application under artificial I/O pressure.	1261	except to put your application under artificial I/O pressure.
1065		1262
1066	=back	1263	=back
		1264
		1265
		1266	=head2 IO::AIO::WD - multiple working directories
		1267
		1268	Your process only has one current working directory, which is used by all
		1269	threads. This makes it hard to use relative paths (some other component
		1270	could call C<chdir> at any time, and it is hard to control when the path
		1271	will be used by IO::AIO).
		1272
		1273	One solution for this is to always use absolute paths. This usually works,
		1274	but can be quite slow (the kernel has to walk the whole path on every
		1275	access), and can also be a hassle to implement.
		1276
		1277	Newer POSIX systems have a number of functions (openat, fdopendir,
		1278	futimensat and so on) that make it possible to specify working directories
		1279	per operation.
		1280
		1281	For portability, and because the clowns who "designed", or shall I write,
		1282	perpetrated this new interface were obviously half-drunk, this abstraction
		1283	cannot be perfect, though.
		1284
		1285	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1286	object. This object stores the canonicalised, absolute version of the
		1287	path, and on systems that allow it, also a directory file descriptor.
		1288
		1289	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1290	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1291	object and a pathname instead. If the pathname is absolute, the
		1292	IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative
		1293	to that IO::AIO::WD object.
		1294
		1295	For example, to get a wd object for F</etc> and then stat F<passwd>
		1296	inside, you would write:
		1297
		1298	aio_wd "/etc", sub {
		1299	my $etcdir = shift;
		1300
		1301	# although $etcdir can be undef on error, there is generally no reason
		1302	# to check for errors here, as aio_stat will fail with ENOENT
		1303	# when $etcdir is undef.
		1304
		1305	aio_stat [$etcdir, "passwd"], sub {
		1306	# yay
		1307	};
		1308	};
		1309
		1310	This shows that creating an IO::AIO::WD object is itself a potentially
		1311	blocking operation, which is why it is done asynchronously.
		1312
		1313	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1314	object and the pathname string, so you could write the following without
		1315	causing any issues due to C<$path> getting reused:
		1316
		1317	my $path = [$wd, undef];
		1318
		1319	for my $name (qw(abc def ghi)) {
		1320	$path->[1] = $name;
		1321	aio_stat $path, sub {
		1322	# ...
		1323	};
		1324	}
		1325
		1326	There are some caveats: when directories get renamed (or deleted), the
		1327	pathname string doesn't change, so will point to the new directory (or
		1328	nowhere at all), while the directory fd, if available on the system,
		1329	will still point to the original directory. Most functions accepting a
		1330	pathname will use the directory fd on newer systems, and the string on
		1331	older systems. Some functions (such as realpath) will always rely on the
		1332	string form of the pathname.
		1333
		1334	So this fucntionality is mainly useful to get some protection against
		1335	C<chdir>, to easily get an absolute path out of a relative path for future
		1336	reference, and to speed up doing many operations in the same directory
		1337	(e.g. when stat'ing all files in a directory).
		1338
		1339	The following functions implement this working directory abstraction:
		1340
		1341	=over 4
		1342
		1343	=item aio_wd $pathname, $callback->($wd)
		1344
		1345	Asynchonously canonicalise the given pathname and convert it to an
		1346	IO::AIO::WD object representing it. If possible and supported on the
		1347	system, also open a directory fd to speed up pathname resolution relative
		1348	to this working directory.
		1349
		1350	If something goes wrong, then C<undef> is passwd to the callback instead
		1351	of a working directory object and C<$!> is set appropriately. Since
		1352	passing C<undef> as working directory component of a pathname fails the
		1353	request with C<ENOENT>, there is often no need for error checking in the
		1354	C<aio_wd> callback, as future requests using the value will fail in the
		1355	expected way.
		1356
		1357	If this call isn't available because your OS lacks it or it couldn't be
		1358	detected, it will be emulated by calling C<fsync> instead.
		1359
		1360	=item IO::AIO::CWD
		1361
		1362	This is a compiletime constant (object) that represents the process
		1363	current working directory.
		1364
		1365	Specifying this object as working directory object for a pathname is as
		1366	if the pathname would be specified directly, without a directory object,
		1367	e.g., these calls are functionally identical:
		1368
		1369	aio_stat "somefile", sub { ... };
		1370	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1371
		1372	=back
		1373
1067		1374
1068	=head2 IO::AIO::REQ CLASS	1375	=head2 IO::AIO::REQ CLASS
1069		1376
1070	All non-aggregate C<aio_*> functions return an object of this class when	1377	All non-aggregate C<aio_*> functions return an object of this class when
1071	called in non-void context.	1378	called in non-void context.
…		…
1249		1556
1250	See C<poll_cb> for an example.	1557	See C<poll_cb> for an example.
1251		1558
1252	=item IO::AIO::poll_cb	1559	=item IO::AIO::poll_cb
1253		1560
1254	Process some outstanding events on the result pipe. You have to call this	1561	Process some outstanding events on the result pipe. You have to call
1255	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1562	this regularly. Returns C<0> if all events could be processed (or there
1256	returned earlier for whatever reason. Returns immediately when no events	1563	were no events to process), or C<-1> if it returned earlier for whatever
1257	are outstanding. The amount of events processed depends on the settings of	1564	reason. Returns immediately when no events are outstanding. The amount of
1258	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1565	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1566	C<IO::AIO::max_poll_time>.
1259		1567
1260	If not all requests were processed for whatever reason, the filehandle	1568	If not all requests were processed for whatever reason, the filehandle
1261	will still be ready when C<poll_cb> returns, so normally you don't have to	1569	will still be ready when C<poll_cb> returns, so normally you don't have to
1262	do anything special to have it called later.	1570	do anything special to have it called later.
1263		1571
		1572	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1573	ready, it can be beneficial to call this function from loops which submit
		1574	a lot of requests, to make sure the results get processed when they become
		1575	available and not just when the loop is finished and the event loop takes
		1576	over again. This function returns very fast when there are no outstanding
		1577	requests.
		1578
1264	Example: Install an Event watcher that automatically calls	1579	Example: Install an Event watcher that automatically calls
1265	IO::AIO::poll_cb with high priority (more examples can be found in the	1580	IO::AIO::poll_cb with high priority (more examples can be found in the
1266	SYNOPSIS section, at the top of this document):	1581	SYNOPSIS section, at the top of this document):
1267		1582
1268	Event->io (fd => IO::AIO::poll_fileno,	1583	Event->io (fd => IO::AIO::poll_fileno,
1269	poll => 'r', async => 1,	1584	poll => 'r', async => 1,
1270	cb => \&IO::AIO::poll_cb);	1585	cb => \&IO::AIO::poll_cb);
		1586
		1587	=item IO::AIO::poll_wait
		1588
		1589	If there are any outstanding requests and none of them in the result
		1590	phase, wait till the result filehandle becomes ready for reading (simply
		1591	does a C<select> on the filehandle. This is useful if you want to
		1592	synchronously wait for some requests to finish).
		1593
		1594	See C<nreqs> for an example.
		1595
		1596	=item IO::AIO::poll
		1597
		1598	Waits until some requests have been handled.
		1599
		1600	Returns the number of requests processed, but is otherwise strictly
		1601	equivalent to:
		1602
		1603	IO::AIO::poll_wait, IO::AIO::poll_cb
		1604
		1605	=item IO::AIO::flush
		1606
		1607	Wait till all outstanding AIO requests have been handled.
		1608
		1609	Strictly equivalent to:
		1610
		1611	IO::AIO::poll_wait, IO::AIO::poll_cb
		1612	while IO::AIO::nreqs;
1271		1613
1272	=item IO::AIO::max_poll_reqs $nreqs	1614	=item IO::AIO::max_poll_reqs $nreqs
1273		1615
1274	=item IO::AIO::max_poll_time $seconds	1616	=item IO::AIO::max_poll_time $seconds
1275		1617
…		…
1300	# use a low priority so other tasks have priority	1642	# use a low priority so other tasks have priority
1301	Event->io (fd => IO::AIO::poll_fileno,	1643	Event->io (fd => IO::AIO::poll_fileno,
1302	poll => 'r', nice => 1,	1644	poll => 'r', nice => 1,
1303	cb => &IO::AIO::poll_cb);	1645	cb => &IO::AIO::poll_cb);
1304		1646
1305	=item IO::AIO::poll_wait
1306
1307	If there are any outstanding requests and none of them in the result
1308	phase, wait till the result filehandle becomes ready for reading (simply
1309	does a C<select> on the filehandle. This is useful if you want to
1310	synchronously wait for some requests to finish).
1311
1312	See C<nreqs> for an example.
1313
1314	=item IO::AIO::poll
1315
1316	Waits until some requests have been handled.
1317
1318	Returns the number of requests processed, but is otherwise strictly
1319	equivalent to:
1320
1321	IO::AIO::poll_wait, IO::AIO::poll_cb
1322
1323	=item IO::AIO::flush
1324
1325	Wait till all outstanding AIO requests have been handled.
1326
1327	Strictly equivalent to:
1328
1329	IO::AIO::poll_wait, IO::AIO::poll_cb
1330	while IO::AIO::nreqs;
1331
1332	=back	1647	=back
1333		1648
1334	=head3 CONTROLLING THE NUMBER OF THREADS	1649	=head3 CONTROLLING THE NUMBER OF THREADS
1335		1650
1336	=over	1651	=over
…		…
1369		1684
1370	Under normal circumstances you don't need to call this function.	1685	Under normal circumstances you don't need to call this function.
1371		1686
1372	=item IO::AIO::max_idle $nthreads	1687	=item IO::AIO::max_idle $nthreads
1373		1688
1374	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1689	Limit the number of threads (default: 4) that are allowed to idle
1375	threads that did not get a request to process within 10 seconds). That	1690	(i.e., threads that did not get a request to process within the idle
1376	means if a thread becomes idle while C<$nthreads> other threads are also	1691	timeout (default: 10 seconds). That means if a thread becomes idle while
1377	idle, it will free its resources and exit.	1692	C<$nthreads> other threads are also idle, it will free its resources and
		1693	exit.
1378		1694
1379	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1695	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1380	to allow for extremely high load situations, but want to free resources	1696	to allow for extremely high load situations, but want to free resources
1381	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1697	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1382		1698
1383	The default is probably ok in most situations, especially if thread	1699	The default is probably ok in most situations, especially if thread
1384	creation is fast. If thread creation is very slow on your system you might	1700	creation is fast. If thread creation is very slow on your system you might
1385	want to use larger values.	1701	want to use larger values.
1386		1702
		1703	=item IO::AIO::idle_timeout $seconds
		1704
		1705	Sets the minimum idle timeout (default 10) after which worker threads are
		1706	allowed to exit. SEe C<IO::AIO::max_idle>.
		1707
1387	=item IO::AIO::max_outstanding $maxreqs	1708	=item IO::AIO::max_outstanding $maxreqs
		1709
		1710	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1711	you do queue up more than this number of requests, the next call to
		1712	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1713	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1714	longer exceeded.
		1715
		1716	In other words, this setting does not enforce a queue limit, but can be
		1717	used to make poll functions block if the limit is exceeded.
1388		1718
1389	This is a very bad function to use in interactive programs because it	1719	This is a very bad function to use in interactive programs because it
1390	blocks, and a bad way to reduce concurrency because it is inexact: Better	1720	blocks, and a bad way to reduce concurrency because it is inexact: Better
1391	use an C<aio_group> together with a feed callback.	1721	use an C<aio_group> together with a feed callback.
1392		1722
1393	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1723	It's main use is in scripts without an event loop - when you want to stat
1394	do queue up more than this number of requests, the next call to the	1724	a lot of files, you can write somehting like this:
1395	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1396	function will block until the limit is no longer exceeded.
1397		1725
1398	The default value is very large, so there is no practical limit on the	1726	IO::AIO::max_outstanding 32;
1399	number of outstanding requests.
1400		1727
1401	You can still queue as many requests as you want. Therefore,	1728	for my $path (...) {
1402	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1729	aio_stat $path , ...;
1403	as a stop gap to shield against fatal memory overflow (with large values).	1730	IO::AIO::poll_cb;
		1731	}
		1732
		1733	IO::AIO::flush;
		1734
		1735	The call to C<poll_cb> inside the loop will normally return instantly, but
		1736	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1737	some requests have been handled. This keeps the loop from pushing a large
		1738	number of C<aio_stat> requests onto the queue.
		1739
		1740	The default value for C<max_outstanding> is very large, so there is no
		1741	practical limit on the number of outstanding requests.
1404		1742
1405	=back	1743	=back
1406		1744
1407	=head3 STATISTICAL INFORMATION	1745	=head3 STATISTICAL INFORMATION
1408		1746
…		…
1446		1784
1447	Returns the number of bytes copied, or C<-1> on error.	1785	Returns the number of bytes copied, or C<-1> on error.
1448		1786
1449	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1787	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1450		1788
1451	Simply calls the C<posix_fadvise> function (see it's	1789	Simply calls the C<posix_fadvise> function (see its
1452	manpage for details). The following advice constants are	1790	manpage for details). The following advice constants are
1453	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1791	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1454	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1792	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1455	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	1793	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1456		1794
1457	On systems that do not implement C<posix_fadvise>, this function returns	1795	On systems that do not implement C<posix_fadvise>, this function returns
1458	ENOSYS, otherwise the return value of C<posix_fadvise>.	1796	ENOSYS, otherwise the return value of C<posix_fadvise>.
1459		1797
		1798	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1799
		1800	Simply calls the C<posix_madvise> function (see its
		1801	manpage for details). The following advice constants are
		1802	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1803	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1804
		1805	On systems that do not implement C<posix_madvise>, this function returns
		1806	ENOSYS, otherwise the return value of C<posix_madvise>.
		1807
		1808	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1809
		1810	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1811	$scalar (see its manpage for details). The following protect
		1812	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1813	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1814
		1815	On systems that do not implement C<mprotect>, this function returns
		1816	ENOSYS, otherwise the return value of C<mprotect>.
		1817
		1818	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1819
		1820	Memory-maps a file (or anonymous memory range) and attaches it to the
		1821	given C<$scalar>, which will act like a string scalar.
		1822
		1823	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1824	change the string length, and most read-only operations such as copying it
		1825	or searching it with regexes and so on.
		1826
		1827	Anything else is unsafe and will, at best, result in memory leaks.
		1828
		1829	The memory map associated with the C<$scalar> is automatically removed
		1830	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1831	C<IO::AIO::munmap> functions are called.
		1832
		1833	This calls the C<mmap>(2) function internally. See your system's manual
		1834	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1835
		1836	The C<$length> must be larger than zero and smaller than the actual
		1837	filesize.
		1838
		1839	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1840	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1841
		1842	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1843	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1844	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1845	(which is set to C<MAP_ANON> if your system only provides this
		1846	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1847	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1848	C<IO::AIO::MAP_NONBLOCK>
		1849
		1850	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1851
		1852	C<$offset> is the offset from the start of the file - it generally must be
		1853	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1854
		1855	Example:
		1856
		1857	use Digest::MD5;
		1858	use IO::AIO;
		1859
		1860	open my $fh, "<verybigfile"
		1861	or die "$!";
		1862
		1863	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1864	or die "verybigfile: $!";
		1865
		1866	my $fast_md5 = md5 $data;
		1867
		1868	=item IO::AIO::munmap $scalar
		1869
		1870	Removes a previous mmap and undefines the C<$scalar>.
		1871
		1872	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1873
		1874	Calls the C<munlock> function, undoing the effects of a previous
		1875	C<aio_mlock> call (see its description for details).
		1876
		1877	=item IO::AIO::munlockall
		1878
		1879	Calls the C<munlockall> function.
		1880
		1881	On systems that do not implement C<munlockall>, this function returns
		1882	ENOSYS, otherwise the return value of C<munlockall>.
		1883
1460	=back	1884	=back
1461		1885
1462	=cut	1886	=cut
1463		1887
1464	min_parallel 8;	1888	min_parallel 8;
1465		1889
1466	END { flush }	1890	END { flush }
1467		1891
1468	1;	1892	1;
1469		1893
		1894	=head1 EVENT LOOP INTEGRATION
		1895
		1896	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1897	automatically into many event loops:
		1898
		1899	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1900	use AnyEvent::AIO;
		1901
		1902	You can also integrate IO::AIO manually into many event loops, here are
		1903	some examples of how to do this:
		1904
		1905	# EV integration
		1906	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1907
		1908	# Event integration
		1909	Event->io (fd => IO::AIO::poll_fileno,
		1910	poll => 'r',
		1911	cb => \&IO::AIO::poll_cb);
		1912
		1913	# Glib/Gtk2 integration
		1914	add_watch Glib::IO IO::AIO::poll_fileno,
		1915	in => sub { IO::AIO::poll_cb; 1 };
		1916
		1917	# Tk integration
		1918	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1919	readable => \&IO::AIO::poll_cb);
		1920
		1921	# Danga::Socket integration
		1922	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1923	\&IO::AIO::poll_cb);
		1924
1470	=head2 FORK BEHAVIOUR	1925	=head2 FORK BEHAVIOUR
1471		1926
1472	This module should do "the right thing" when the process using it forks:	1927	Usage of pthreads in a program changes the semantics of fork
		1928	considerably. Specifically, only async-safe functions can be called after
		1929	fork. Perl doesn't know about this, so in general, you cannot call fork
		1930	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		1931	pthreads, so this applies, but many other extensions and (for inexplicable
		1932	reasons) perl itself often is linked against pthreads, so this limitation
		1933	applies to quite a lot of perls.
1473		1934
1474	Before the fork, IO::AIO enters a quiescent state where no requests	1935	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1475	can be added in other threads and no results will be processed. After	1936	only works in the process that loaded it. Forking is fully supported, but
1476	the fork the parent simply leaves the quiescent state and continues	1937	using IO::AIO in the child is not.
1477	request/result processing, while the child frees the request/result queue
1478	(so that the requests started before the fork will only be handled in the
1479	parent). Threads will be started on demand until the limit set in the
1480	parent process has been reached again.
1481		1938
1482	In short: the parent will, after a short pause, continue as if fork had	1939	You might get around by not I<using> IO::AIO before (or after)
1483	not been called, while the child will act as if IO::AIO has not been used	1940	forking. You could also try to call the L<IO::AIO::reinit> function in the
1484	yet.	1941	child:
		1942
		1943	=over 4
		1944
		1945	=item IO::AIO::reinit
		1946
		1947	Abandons all current requests and I/O threads and simply reinitialises all
		1948	data structures. This is not an operation supported by any standards, but
		1949	happens to work on GNU/Linux and some newer BSD systems.
		1950
		1951	The only reasonable use for this function is to call it after forking, if
		1952	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1953	the process will result in undefined behaviour. Calling it at any time
		1954	will also result in any undefined (by POSIX) behaviour.
		1955
		1956	=back
1485		1957
1486	=head2 MEMORY USAGE	1958	=head2 MEMORY USAGE
1487		1959
1488	Per-request usage:	1960	Per-request usage:
1489		1961

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.170 by root, Sat Jan 2 14:11:32 2010 UTC vs. Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.170 by root, Sat Jan 2 14:11:32 2010 UTC vs.
Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC