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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.163 by root, Wed Aug 5 11:53:16 2009 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 = '3.3';	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
		183	aio_msync aio_mtouch aio_mlock aio_mlockall
		184	aio_statvfs
		185	aio_wd);
205		186
206	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
207	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
208	min_parallel max_parallel max_idle	189	min_parallel max_parallel max_idle idle_timeout
209	nreqs nready npending nthreads	190	nreqs nready npending nthreads
210	max_poll_time max_poll_reqs	191	max_poll_time max_poll_reqs
211	sendfile fadvise);	192	sendfile fadvise madvise
		193	mmap munmap munlock munlockall);
212		194
213	push @AIO_REQ, qw(aio_busy); # not exported	195	push @AIO_REQ, qw(aio_busy); # not exported
214		196
215	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	197	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
216		198
217	require XSLoader;	199	require XSLoader;
218	XSLoader::load ("IO::AIO", $VERSION);	200	XSLoader::load ("IO::AIO", $VERSION);
219	}	201	}
220		202
221	=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
222		280
223	=head2 AIO REQUEST FUNCTIONS	281	=head2 AIO REQUEST FUNCTIONS
224		282
225	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
226	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,
…		…
234	internally until the request has finished.	292	internally until the request has finished.
235		293
236	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
237	further manipulation of those requests while they are in-flight.	295	further manipulation of those requests while they are in-flight.
238		296
239	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
240	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
241	request is being executed, the current working directory could have	299	current working directory could have changed. Alternatively, you can make
242	changed. Alternatively, you can make sure that you never change the	300	sure that you never change the current working directory anywhere in
243	current working directory anywhere in the program and then use relative	301	the program and then use relative paths. Lastly, you can take advantage
244	paths.	302	of IO::AIOs working directory abstraction - see the description of the
		303	C<IO::AIO::WD> class later in this document.
245		304
246	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
247	in filenames you got from outside (command line, readdir etc.) without	306	in filenames you got from outside (command line, readdir etc.) without
248	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
249	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
…		…
306	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
307	change the umask.	366	change the umask.
308		367
309	Example:	368	Example:
310		369
311	aio_open "/etc/passwd", O_RDONLY, 0, sub {	370	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
312	if ($_[0]) {	371	if ($_[0]) {
313	print "open successful, fh is $_[0]\n";	372	print "open successful, fh is $_[0]\n";
314	...	373	...
315	} else {	374	} else {
316	die "open failed: $!\n";	375	die "open failed: $!\n";
317	}	376	}
318	};	377	};
319		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
320		388
321	=item aio_close $fh, $callback->($status)	389	=item aio_close $fh, $callback->($status)
322		390
323	Asynchronously close a file and call the callback with the result	391	Asynchronously close a file and call the callback with the result
324	code.	392	code.
…		…
374		442
375	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
376	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
377	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
378	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
379	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>.
380		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<$in_fh>) is a file - the file I/O will then be asynchronous, while
		459	the socket I/O will be non-blocking. Note, however, that you can run
		460	into a trap where C<aio_sendfile> reads some data with readahead, then
		461	fails to write all data, and when the socket is ready the next time, the
		462	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		463	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		464	resource usage.
		465
381	This call tries to make use of a native C<sendfile> syscall to provide	466	This call tries to make use of a native C<sendfile>-like syscall to
382	zero-copy operation. For this to work, C<$out_fh> should refer to a	467	provide zero-copy operation. For this to work, C<$out_fh> should refer to
383	socket, and C<$in_fh> should refer to mmap'able file.	468	a socket, and C<$in_fh> should refer to an mmap'able file.
384		469
385	If the native sendfile call fails or is not implemented, it will be	470	If a native sendfile cannot be found or it fails with C<ENOSYS>,
386	emulated, so you can call C<aio_sendfile> on any type of filehandle	471	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		472	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
387	regardless of the limitations of the operating system.	473	type of filehandle regardless of the limitations of the operating system.
388		474
389	Please note, however, that C<aio_sendfile> can read more bytes from	475	As native sendfile syscalls (as practically any non-POSIX interface hacked
390	C<$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
391	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
392	provides the number of bytes written to C<$out_fh>. Only if the result	478	in Linux and FreeBSD kernels (probably others, too), but that might fail,
393	value equals C<$length> one can assume that C<$length> bytes have been	479	so you really really should check the return value of C<aio_sendfile> -
394	read.	480	fewre bytes than expected might have been transferred.
395		481
396		482
397	=item aio_readahead $fh,$offset,$length, $callback->($retval)	483	=item aio_readahead $fh,$offset,$length, $callback->($retval)
398		484
399	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
…		…
422		508
423	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
424	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
425	unless perl itself is compiled with large file support.	511	unless perl itself is compiled with large file support.
426		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
427	Example: Print the length of F</etc/passwd>:	522	Example: Print the length of F</etc/passwd>:
428		523
429	aio_stat "/etc/passwd", sub {	524	aio_stat "/etc/passwd", sub {
430	$_[0] and die "stat failed: $!";	525	$_[0] and die "stat failed: $!";
431	print "size is ", -s _, "\n";	526	print "size is ", -s _, "\n";
432	};	527	};
433		528
434		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
435	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	575	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
436		576
437	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
438	and $mtime being undef). Fractional times are supported if the underlying	578	and $mtime being undef). Fractional times are supported if the underlying
439	syscalls support them.	579	syscalls support them.
…		…
477		617
478	Asynchronously unlink (delete) a file and call the callback with the	618	Asynchronously unlink (delete) a file and call the callback with the
479	result code.	619	result code.
480		620
481		621
482	=item aio_mknod $path, $mode, $dev, $callback->($status)	622	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
483		623
484	[EXPERIMENTAL]	624	[EXPERIMENTAL]
485		625
486	Asynchronously create a device node (or fifo). See mknod(2).	626	Asynchronously create a device node (or fifo). See mknod(2).
487		627
488	The only (POSIX-) portable way of calling this function is:	628	The only (POSIX-) portable way of calling this function is:
489		629
490	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	630	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
491		631
		632	See C<aio_stat> for info about some potentially helpful extra constants
		633	and functions.
492		634
493	=item aio_link $srcpath, $dstpath, $callback->($status)	635	=item aio_link $srcpath, $dstpath, $callback->($status)
494		636
495	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
496	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.
…		…
500		642
501	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
502	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.
503		645
504		646
505	=item aio_readlink $path, $callback->($link)	647	=item aio_readlink $pathname, $callback->($link)
506		648
507	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
508	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
509	callback.	651	callback.
510		652
511		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
512	=item aio_rename $srcpath, $dstpath, $callback->($status)	664	=item aio_rename $srcpath, $dstpath, $callback->($status)
513		665
514	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
515	rename(2) and call the callback with the result code.	667	rename(2) and call the callback with the result code.
516		668
…		…
538	array-ref with the filenames.	690	array-ref with the filenames.
539		691
540		692
541	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	693	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
542		694
543	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	695	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
544	behaviour and output format. In case of an error, C<$entries> will be	696	tune behaviour and output format. In case of an error, C<$entries> will be
545	C<undef>.	697	C<undef>.
546		698
547	The flags are a combination of the following constants, ORed together (the	699	The flags are a combination of the following constants, ORed together (the
548	flags will also be passed to the callback, possibly modified):	700	flags will also be passed to the callback, possibly modified):
549		701
550	=over 4	702	=over 4
551		703
552	=item IO::AIO::READDIR_DENTS	704	=item IO::AIO::READDIR_DENTS
553		705
554	When this flag is off, then the callback gets an arrayref with of names	706	When this flag is off, then the callback gets an arrayref consisting of
555	only (as with C<aio_readdir>), otherwise it gets an arrayref with	707	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
556	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	708	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
557	entry in more detail.	709	entry in more detail.
558		710
559	C<$name> is the name of the entry.	711	C<$name> is the name of the entry.
560		712
…		…
573	systems that do not deliver the inode information.	725	systems that do not deliver the inode information.
574		726
575	=item IO::AIO::READDIR_DIRS_FIRST	727	=item IO::AIO::READDIR_DIRS_FIRST
576		728
577	When this flag is set, then the names will be returned in an order where	729	When this flag is set, then the names will be returned in an order where
578	likely directories come first. This is useful when you need to quickly	730	likely directories come first, in optimal stat order. This is useful when
579	find directories, or you want to find all directories while avoiding to	731	you need to quickly find directories, or you want to find all directories
580	stat() each entry.	732	while avoiding to stat() each entry.
581		733
582	If the system returns type information in readdir, then this is used	734	If the system returns type information in readdir, then this is used
583	to find directories directly. Otherwise, likely directories are files	735	to find directories directly. Otherwise, likely directories are names
584	beginning with ".", or otherwise files with no dots, of which files with	736	beginning with ".", or otherwise names with no dots, of which names with
585	short names are tried first.	737	short names are tried first.
586		738
587	=item IO::AIO::READDIR_STAT_ORDER	739	=item IO::AIO::READDIR_STAT_ORDER
588		740
589	When this flag is set, then the names will be returned in an order	741	When this flag is set, then the names will be returned in an order
…		…
596		748
597	=item IO::AIO::READDIR_FOUND_UNKNOWN	749	=item IO::AIO::READDIR_FOUND_UNKNOWN
598		750
599	This flag should not be set when calling C<aio_readdirx>. Instead, it	751	This flag should not be set when calling C<aio_readdirx>. Instead, it
600	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	752	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
601	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	753	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
602	C<$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.
603		755
604	=back	756	=back
605		757
606		758
607	=item aio_load $path, $data, $callback->($status)	759	=item aio_load $pathname, $data, $callback->($status)
608		760
609	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
610	memory. Status is the same as with aio_read.	762	memory. Status is the same as with aio_read.
611		763
612	=cut	764	=cut
…		…
634		786
635	=item aio_copy $srcpath, $dstpath, $callback->($status)	787	=item aio_copy $srcpath, $dstpath, $callback->($status)
636		788
637	Try to copy the I<file> (directories not supported as either source or	789	Try to copy the I<file> (directories not supported as either source or
638	destination) from C<$srcpath> to C<$dstpath> and call the callback with	790	destination) from C<$srcpath> to C<$dstpath> and call the callback with
639	the C<0> (error) or C<-1> ok.	791	a status of C<0> (ok) or C<-1> (error, see C<$!>).
640		792
641	This is a composite request that creates the destination file with	793	This is a composite request that creates the destination file with
642	mode 0200 and copies the contents of the source file into it using	794	mode 0200 and copies the contents of the source file into it using
643	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	795	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
644	uid/gid, in that order.	796	uid/gid, in that order.
…		…
656	my $grp = aio_group $cb;	808	my $grp = aio_group $cb;
657		809
658	aioreq_pri $pri;	810	aioreq_pri $pri;
659	add $grp aio_open $src, O_RDONLY, 0, sub {	811	add $grp aio_open $src, O_RDONLY, 0, sub {
660	if (my $src_fh = $_[0]) {	812	if (my $src_fh = $_[0]) {
661	my @stat = stat $src_fh; # hmm, might bock over nfs?	813	my @stat = stat $src_fh; # hmm, might block over nfs?
662		814
663	aioreq_pri $pri;	815	aioreq_pri $pri;
664	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	816	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
665	if (my $dst_fh = $_[0]) {	817	if (my $dst_fh = $_[0]) {
666	aioreq_pri $pri;	818	aioreq_pri $pri;
…		…
713		865
714	=item aio_move $srcpath, $dstpath, $callback->($status)	866	=item aio_move $srcpath, $dstpath, $callback->($status)
715		867
716	Try to move the I<file> (directories not supported as either source or	868	Try to move the I<file> (directories not supported as either source or
717	destination) from C<$srcpath> to C<$dstpath> and call the callback with	869	destination) from C<$srcpath> to C<$dstpath> and call the callback with
718	the C<0> (error) or C<-1> ok.	870	a status of C<0> (ok) or C<-1> (error, see C<$!>).
719		871
720	This is a composite request that tries to rename(2) the file first; if	872	This is a composite request that tries to rename(2) the file first; if
721	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if	873	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
722	that is successful, unlinks the C<$srcpath>.	874	that is successful, unlinks the C<$srcpath>.
723		875
…		…
734	if ($_[0] && $! == EXDEV) {	886	if ($_[0] && $! == EXDEV) {
735	aioreq_pri $pri;	887	aioreq_pri $pri;
736	add $grp aio_copy $src, $dst, sub {	888	add $grp aio_copy $src, $dst, sub {
737	$grp->result ($_[0]);	889	$grp->result ($_[0]);
738		890
739	if (!$_[0]) {	891	unless ($_[0]) {
740	aioreq_pri $pri;	892	aioreq_pri $pri;
741	add $grp aio_unlink $src;	893	add $grp aio_unlink $src;
742	}	894	}
743	};	895	};
744	} else {	896	} else {
…		…
747	};	899	};
748		900
749	$grp	901	$grp
750	}	902	}
751		903
752	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	904	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
753		905
754	Scans a directory (similar to C<aio_readdir>) but additionally tries to	906	Scans a directory (similar to C<aio_readdir>) but additionally tries to
755	efficiently separate the entries of directory C<$path> into two sets of	907	efficiently separate the entries of directory C<$path> into two sets of
756	names, directories you can recurse into (directories), and ones you cannot	908	names, directories you can recurse into (directories), and ones you cannot
757	recurse into (everything else, including symlinks to directories).	909	recurse into (everything else, including symlinks to directories).
…		…
788	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
789	currently) and likely non-directories (see C<aio_readdirx>). Then every	941	currently) and likely non-directories (see C<aio_readdirx>). Then every
790	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,
791	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
792	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
793	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
794	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
795	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
796	the filetype information on readdir.	948	the filetype information on readdir.
797		949
798	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
…		…
884	};	1036	};
885		1037
886	$grp	1038	$grp
887	}	1039	}
888		1040
889	=item aio_rmtree $path, $callback->($status)	1041	=item aio_rmtree $pathname, $callback->($status)
890		1042
891	Delete a directory tree starting (and including) C<$path>, return the	1043	Delete a directory tree starting (and including) C<$path>, return the
892	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
893	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
894	everything else.	1046	everything else.
…		…
936	callback with the fdatasync result code.	1088	callback with the fdatasync result code.
937		1089
938	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
939	detected, it will be emulated by calling C<fsync> instead.	1091	detected, it will be emulated by calling C<fsync> instead.
940		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
941	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1100	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
942		1101
943	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>
944	to disk (but NOT the metadata), by calling the Linux-specific	1103	to disk (but NOT the metadata), by calling the Linux-specific
945	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
…		…
948	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>,
949	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1108	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
950	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
951	manpage for details.	1110	manpage for details.
952		1111
953	=item aio_pathsync $path, $callback->($status)	1112	=item aio_pathsync $pathname, $callback->($status)
954		1113
955	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
956	composite request intended to sync directories after directory operations	1115	composite request intended to sync directories after directory operations
957	(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
958	specific effect, but usually it makes sure that directory changes get	1117	specific effect, but usually it makes sure that directory changes get
…		…
989	};	1148	};
990		1149
991	$grp	1150	$grp
992	}	1151	}
993		1152
		1153	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1154
		1155	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		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
		1158	scalar must only be modified in-place while an aio operation is pending on
		1159	it).
		1160
		1161	It calls the C<msync> function of your OS, if available, with the memory
		1162	area starting at C<$offset> in the string and ending C<$length> bytes
		1163	later. If C<$length> is negative, counts from the end, and if C<$length>
		1164	is C<undef>, then it goes till the end of the string. The flags can be
		1165	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1166	C<IO::AIO::MS_SYNC>.
		1167
		1168	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1169
		1170	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1171	scalars.
		1172
		1173	It touches (reads or writes) all memory pages in the specified
		1174	range inside the scalar. All caveats and parameters are the same
		1175	as for C<aio_msync>, above, except for flags, which must be either
		1176	C<0> (which reads all pages and ensures they are instantiated) or
		1177	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1178	writing an octet from it, which dirties the page).
		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
994	=item aio_group $callback->(...)	1219	=item aio_group $callback->(...)
995		1220
996	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
997	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
998	many requests into a single, composite, request with a definite callback	1223	many requests into a single, composite, request with a definite callback
…		…
1034	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
1035	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
1036	except to put your application under artificial I/O pressure.	1261	except to put your application under artificial I/O pressure.
1037		1262
1038	=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
1039		1374
1040	=head2 IO::AIO::REQ CLASS	1375	=head2 IO::AIO::REQ CLASS
1041		1376
1042	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
1043	called in non-void context.	1378	called in non-void context.
…		…
1133	=item $grp->cancel_subs	1468	=item $grp->cancel_subs
1134		1469
1135	Cancel all subrequests and clears any feeder, but not the group request	1470	Cancel all subrequests and clears any feeder, but not the group request
1136	itself. Useful when you queued a lot of events but got a result early.	1471	itself. Useful when you queued a lot of events but got a result early.
1137		1472
		1473	The group request will finish normally (you cannot add requests to the
		1474	group).
		1475
1138	=item $grp->result (...)	1476	=item $grp->result (...)
1139		1477
1140	Set the result value(s) that will be passed to the group callback when all	1478	Set the result value(s) that will be passed to the group callback when all
1141	subrequests have finished and set the groups errno to the current value	1479	subrequests have finished and set the groups errno to the current value
1142	of errno (just like calling C<errno> without an error number). By default,	1480	of errno (just like calling C<errno> without an error number). By default,
…		…
1218		1556
1219	See C<poll_cb> for an example.	1557	See C<poll_cb> for an example.
1220		1558
1221	=item IO::AIO::poll_cb	1559	=item IO::AIO::poll_cb
1222		1560
1223	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
1224	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
1225	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
1226	are outstanding. The amount of events processed depends on the settings of	1564	reason. Returns immediately when no events are outstanding. The amount of
1227	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>.
1228		1567
1229	If not all requests were processed for whatever reason, the filehandle	1568	If not all requests were processed for whatever reason, the filehandle
1230	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
1231	do anything special to have it called later.	1570	do anything special to have it called later.
1232		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
1233	Example: Install an Event watcher that automatically calls	1579	Example: Install an Event watcher that automatically calls
1234	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
1235	SYNOPSIS section, at the top of this document):	1581	SYNOPSIS section, at the top of this document):
1236		1582
1237	Event->io (fd => IO::AIO::poll_fileno,	1583	Event->io (fd => IO::AIO::poll_fileno,
1238	poll => 'r', async => 1,	1584	poll => 'r', async => 1,
1239	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;
1240		1613
1241	=item IO::AIO::max_poll_reqs $nreqs	1614	=item IO::AIO::max_poll_reqs $nreqs
1242		1615
1243	=item IO::AIO::max_poll_time $seconds	1616	=item IO::AIO::max_poll_time $seconds
1244		1617
…		…
1269	# use a low priority so other tasks have priority	1642	# use a low priority so other tasks have priority
1270	Event->io (fd => IO::AIO::poll_fileno,	1643	Event->io (fd => IO::AIO::poll_fileno,
1271	poll => 'r', nice => 1,	1644	poll => 'r', nice => 1,
1272	cb => &IO::AIO::poll_cb);	1645	cb => &IO::AIO::poll_cb);
1273		1646
1274	=item IO::AIO::poll_wait
1275
1276	If there are any outstanding requests and none of them in the result
1277	phase, wait till the result filehandle becomes ready for reading (simply
1278	does a C<select> on the filehandle. This is useful if you want to
1279	synchronously wait for some requests to finish).
1280
1281	See C<nreqs> for an example.
1282
1283	=item IO::AIO::poll
1284
1285	Waits until some requests have been handled.
1286
1287	Returns the number of requests processed, but is otherwise strictly
1288	equivalent to:
1289
1290	IO::AIO::poll_wait, IO::AIO::poll_cb
1291
1292	=item IO::AIO::flush
1293
1294	Wait till all outstanding AIO requests have been handled.
1295
1296	Strictly equivalent to:
1297
1298	IO::AIO::poll_wait, IO::AIO::poll_cb
1299	while IO::AIO::nreqs;
1300
1301	=back	1647	=back
1302		1648
1303	=head3 CONTROLLING THE NUMBER OF THREADS	1649	=head3 CONTROLLING THE NUMBER OF THREADS
1304		1650
1305	=over	1651	=over
…		…
1338		1684
1339	Under normal circumstances you don't need to call this function.	1685	Under normal circumstances you don't need to call this function.
1340		1686
1341	=item IO::AIO::max_idle $nthreads	1687	=item IO::AIO::max_idle $nthreads
1342		1688
1343	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1689	Limit the number of threads (default: 4) that are allowed to idle
1344	threads that did not get a request to process within 10 seconds). That	1690	(i.e., threads that did not get a request to process within the idle
1345	means if a thread becomes idle while C<$nthreads> other threads are also	1691	timeout (default: 10 seconds). That means if a thread becomes idle while
1346	idle, it will free its resources and exit.	1692	C<$nthreads> other threads are also idle, it will free its resources and
		1693	exit.
1347		1694
1348	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)
1349	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
1350	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1697	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1351		1698
1352	The default is probably ok in most situations, especially if thread	1699	The default is probably ok in most situations, especially if thread
1353	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
1354	want to use larger values.	1701	want to use larger values.
1355		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
1356	=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.
1357		1718
1358	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
1359	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
1360	use an C<aio_group> together with a feed callback.	1721	use an C<aio_group> together with a feed callback.
1361		1722
1362	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
1363	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:
1364	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1365	function will block until the limit is no longer exceeded.
1366		1725
1367	The default value is very large, so there is no practical limit on the	1726	IO::AIO::max_outstanding 32;
1368	number of outstanding requests.
1369		1727
1370	You can still queue as many requests as you want. Therefore,	1728	for my $path (...) {
1371	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1729	aio_stat $path , ...;
1372	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.
1373		1742
1374	=back	1743	=back
1375		1744
1376	=head3 STATISTICAL INFORMATION	1745	=head3 STATISTICAL INFORMATION
1377		1746
…		…
1415		1784
1416	Returns the number of bytes copied, or C<-1> on error.	1785	Returns the number of bytes copied, or C<-1> on error.
1417		1786
1418	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1787	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1419		1788
1420	Simply calls the C<posix_fadvise> function (see it's	1789	Simply calls the C<posix_fadvise> function (see its
1421	manpage for details). The following advice constants are	1790	manpage for details). The following advice constants are
1422	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1791	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1423	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1792	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1424	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	1793	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1425		1794
1426	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
1427	ENOSYS, otherwise the return value of C<posix_fadvise>.	1796	ENOSYS, otherwise the return value of C<posix_fadvise>.
1428		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
1429	=back	1884	=back
1430		1885
1431	=cut	1886	=cut
1432		1887
1433	min_parallel 8;	1888	min_parallel 8;
1434		1889
1435	END { flush }	1890	END { flush }
1436		1891
1437	1;	1892	1;
1438		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
1439	=head2 FORK BEHAVIOUR	1925	=head2 FORK BEHAVIOUR
1440		1926
1441	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.
1442		1934
1443	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
1444	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
1445	the fork the parent simply leaves the quiescent state and continues	1937	using IO::AIO in the child is not.
1446	request/result processing, while the child frees the request/result queue
1447	(so that the requests started before the fork will only be handled in the
1448	parent). Threads will be started on demand until the limit set in the
1449	parent process has been reached again.
1450		1938
1451	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)
1452	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
1453	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
1454		1957
1455	=head2 MEMORY USAGE	1958	=head2 MEMORY USAGE
1456		1959
1457	Per-request usage:	1960	Per-request usage:
1458		1961

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing IO-AIO/AIO.pm (file contents): Revision 1.163 by root, Wed Aug 5 11:53:16 2009 UTC vs. Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.163 by root, Wed Aug 5 11:53:16 2009 UTC vs.
Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC