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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs.
Revision 1.207 by root, Mon Jul 25 16:50:33 2011 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32	use AnyEvent::AIO;
33
34	# EV integration
35	my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37	# Event integration
38	Event->io (fd => IO::AIO::poll_fileno,
39	poll => 'r',
40	cb => \&IO::AIO::poll_cb);
41
42	# Glib/Gtk2 integration
43	add_watch Glib::IO IO::AIO::poll_fileno,
44	in => sub { IO::AIO::poll_cb; 1 };
45
46	# Tk integration
47	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48	readable => \&IO::AIO::poll_cb);
49
50	# Danga::Socket integration
51	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52	\&IO::AIO::poll_cb);
53
54	=head1 DESCRIPTION	31	=head1 DESCRIPTION
55		32
56	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
57	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
58		36
59	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
60	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
61	will still block, but you can do something else in the meantime. This	39	will still block, but you can do something else in the meantime. This
62	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
66	on a RAID volume or over NFS when you do a number of stat operations	44	on a RAID volume or over NFS when you do a number of stat operations
67	concurrently.	45	concurrently.
68		46
69	While most of this works on all types of file descriptors (for	47	While most of this works on all types of file descriptors (for
70	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
71	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
72	inefficient. Use an event loop for that (such as the L<Event\|Event>	50	very inefficient. Use an event loop for that (such as the L<EV>
73	module): IO::AIO will naturally fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
74		52
75	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
76	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
77	in perl, and the threads created by this module will not be visible	55	in perl, and the threads created by this module will not be visible
…		…
87	yourself, always call C<poll_cb> from within the same thread, or never	65	yourself, always call C<poll_cb> from within the same thread, or never
88	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
89		67
90	=head2 EXAMPLE	68	=head2 EXAMPLE
91		69
92	This is a simple example that uses the Event module and loads	70	This is a simple example that uses the EV module and loads
93	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
94		72
95	use Fcntl;	73	use Fcntl;
96	use Event;	74	use EV;
97	use IO::AIO;	75	use IO::AIO;
98		76
99	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
100	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
101	poll => 'r',
102	cb => \&IO::AIO::poll_cb);
103		79
104	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
105	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
106	my $fh = shift	82	my $fh = shift
107	or die "error while opening: $!";	83	or die "error while opening: $!";
108		84
109	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
110	my $size = -s $fh;	86	my $size = -s $fh;
…		…
119		95
120	# file contents now in $contents	96	# file contents now in $contents
121	print $contents;	97	print $contents;
122		98
123	# exit event loop and program	99	# exit event loop and program
124	Event::unloop;	100	EV::unloop;
125	};	101	};
126	};	102	};
127		103
128	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
129	# check for sockets etc. etc.	105	# check for sockets etc. etc.
130		106
131	# process events as long as there are some:	107	# process events as long as there are some:
132	Event::loop;	108	EV::loop;
133		109
134	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
135		111
136	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
137	directly visible to Perl.	113	directly visible to Perl.
…		…
187		163
188	package IO::AIO;	164	package IO::AIO;
189		165
190	use Carp ();	166	use Carp ();
191		167
192	no warnings;	168	use common::sense;
193	use strict 'vars';
194		169
195	use base 'Exporter';	170	use base 'Exporter';
196		171
197	BEGIN {	172	BEGIN {
198	our $VERSION = '3.19';	173	our $VERSION = '4.0';
199		174
200	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
201	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
202	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
203	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
204	aio_rename aio_link aio_move aio_copy aio_group	180	aio_rename aio_link aio_move aio_copy aio_group
205	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
206	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);
207		185
208	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
209	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
210	min_parallel max_parallel max_idle	188	min_parallel max_parallel max_idle idle_timeout
211	nreqs nready npending nthreads	189	nreqs nready npending nthreads
212	max_poll_time max_poll_reqs);	190	max_poll_time max_poll_reqs
		191	sendfile fadvise madvise
		192	mmap munmap munlock munlockall);
213		193
214	push @AIO_REQ, qw(aio_busy); # not exported	194	push @AIO_REQ, qw(aio_busy); # not exported
215		195
216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	196	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217		197
218	require XSLoader;	198	require XSLoader;
219	XSLoader::load ("IO::AIO", $VERSION);	199	XSLoader::load ("IO::AIO", $VERSION);
220	}	200	}
221		201
222	=head1 FUNCTIONS	202	=head1 FUNCTIONS
		203
		204	=head2 QUICK OVERVIEW
		205
		206	This section simply lists the prototypes of the most important functions
		207	for quick reference. See the following sections for function-by-function
		208	documentation.
		209
		210	aio_open $pathname, $flags, $mode, $callback->($fh)
		211	aio_close $fh, $callback->($status)
		212	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		214	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		215	aio_readahead $fh,$offset,$length, $callback->($retval)
		216	aio_stat $fh_or_path, $callback->($status)
		217	aio_lstat $fh, $callback->($status)
		218	aio_statvfs $fh_or_path, $callback->($statvfs)
		219	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		220	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		221	aio_truncate $fh_or_path, $offset, $callback->($status)
		222	aio_chmod $fh_or_path, $mode, $callback->($status)
		223	aio_unlink $pathname, $callback->($status)
		224	aio_mknod $path, $mode, $dev, $callback->($status)
		225	aio_link $srcpath, $dstpath, $callback->($status)
		226	aio_symlink $srcpath, $dstpath, $callback->($status)
		227	aio_readlink $path, $callback->($link)
		228	aio_realpath $path, $callback->($link)
		229	aio_rename $srcpath, $dstpath, $callback->($status)
		230	aio_mkdir $pathname, $mode, $callback->($status)
		231	aio_rmdir $pathname, $callback->($status)
		232	aio_readdir $pathname, $callback->($entries)
		233	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		234	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		235	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		236	aio_load $path, $data, $callback->($status)
		237	aio_copy $srcpath, $dstpath, $callback->($status)
		238	aio_move $srcpath, $dstpath, $callback->($status)
		239	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		240	aio_rmtree $path, $callback->($status)
		241	aio_sync $callback->($status)
		242	aio_syncfs $fh, $callback->($status)
		243	aio_fsync $fh, $callback->($status)
		244	aio_fdatasync $fh, $callback->($status)
		245	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		246	aio_pathsync $path, $callback->($status)
		247	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		248	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		249	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		250	aio_mlockall $flags, $callback->($status)
		251	aio_group $callback->(...)
		252	aio_nop $callback->()
		253
		254	$prev_pri = aioreq_pri [$pri]
		255	aioreq_nice $pri_adjust
		256
		257	IO::AIO::poll_wait
		258	IO::AIO::poll_cb
		259	IO::AIO::poll
		260	IO::AIO::flush
		261	IO::AIO::max_poll_reqs $nreqs
		262	IO::AIO::max_poll_time $seconds
		263	IO::AIO::min_parallel $nthreads
		264	IO::AIO::max_parallel $nthreads
		265	IO::AIO::max_idle $nthreads
		266	IO::AIO::idle_timeout $seconds
		267	IO::AIO::max_outstanding $maxreqs
		268	IO::AIO::nreqs
		269	IO::AIO::nready
		270	IO::AIO::npending
		271
		272	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		273	IO::AIO::fadvise $fh, $offset, $len, $advice
		274	IO::AIO::madvise $scalar, $offset, $length, $advice
		275	IO::AIO::mprotect $scalar, $offset, $length, $protect
		276	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		277	IO::AIO::munlockall
223		278
224	=head2 AIO REQUEST FUNCTIONS	279	=head2 AIO REQUEST FUNCTIONS
225		280
226	All the C<aio_*> calls are more or less thin wrappers around the syscall	281	All the C<aio_*> calls are more or less thin wrappers around the syscall
227	with the same name (sans C<aio_>). The arguments are similar or identical,	282	with the same name (sans C<aio_>). The arguments are similar or identical,
…		…
307	by the umask in effect then the request is being executed, so better never	362	by the umask in effect then the request is being executed, so better never
308	change the umask.	363	change the umask.
309		364
310	Example:	365	Example:
311		366
312	aio_open "/etc/passwd", O_RDONLY, 0, sub {	367	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313	if ($_[0]) {	368	if ($_[0]) {
314	print "open successful, fh is $_[0]\n";	369	print "open successful, fh is $_[0]\n";
315	...	370	...
316	} else {	371	} else {
317	die "open failed: $!\n";	372	die "open failed: $!\n";
318	}	373	}
319	};	374	};
320		375
		376	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		377	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		378	following POSIX and non-POSIX constants are available (missing ones on
		379	your system are, as usual, C<0>):
		380
		381	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		382	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		383	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		384
321		385
322	=item aio_close $fh, $callback->($status)	386	=item aio_close $fh, $callback->($status)
323		387
324	Asynchronously close a file and call the callback with the result	388	Asynchronously close a file and call the callback with the result
325	code.	389	code.
…		…
375		439
376	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	440	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377	reading at byte offset C<$in_offset>, and starts writing at the current	441	reading at byte offset C<$in_offset>, and starts writing at the current
378	file offset of C<$out_fh>. Because of that, it is not safe to issue more	442	file offset of C<$out_fh>. Because of that, it is not safe to issue more
379	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	443	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380	other.	444	other. The same C<$in_fh> works fine though, as this function does not
		445	move or use the file offset of C<$in_fh>.
381		446
		447	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		448	are written, and there is no way to find out how many more bytes have been
		449	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		450	number of bytes written to C<$out_fh>. Only if the result value equals
		451	C<$length> one can assume that C<$length> bytes have been read.
		452
		453	Unlike with other C<aio_> functions, it makes a lot of sense to use
		454	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		455	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		456	the socket I/O will be non-blocking. Note, however, that you can run
		457	into a trap where C<aio_sendfile> reads some data with readahead, then
		458	fails to write all data, and when the socket is ready the next time, the
		459	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		460	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		461	resource usage.
		462
382	This call tries to make use of a native C<sendfile> syscall to provide	463	This call tries to make use of a native C<sendfile>-like syscall to
383	zero-copy operation. For this to work, C<$out_fh> should refer to a	464	provide zero-copy operation. For this to work, C<$out_fh> should refer to
384	socket, and C<$in_fh> should refer to mmap'able file.	465	a socket, and C<$in_fh> should refer to an mmap'able file.
385		466
386	If the native sendfile call fails or is not implemented, it will be	467	If a native sendfile cannot be found or it fails with C<ENOSYS>,
387	emulated, so you can call C<aio_sendfile> on any type of filehandle	468	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		469	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
388	regardless of the limitations of the operating system.	470	type of filehandle regardless of the limitations of the operating system.
389		471
390	Please note, however, that C<aio_sendfile> can read more bytes from	472	As native sendfile syscalls (as practically any non-POSIX interface hacked
391	C<$in_fh> than are written, and there is no way to find out how many	473	together in a hurry to improve benchmark numbers) tend to be rather buggy
392	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	474	on many systems, this implementation tries to work around some known bugs
393	provides the number of bytes written to C<$out_fh>. Only if the result	475	in Linux and FreeBSD kernels (probably others, too), but that might fail,
394	value equals C<$length> one can assume that C<$length> bytes have been	476	so you really really should check the return value of C<aio_sendfile> -
395	read.	477	fewre bytes than expected might have been transferred.
396		478
397		479
398	=item aio_readahead $fh,$offset,$length, $callback->($retval)	480	=item aio_readahead $fh,$offset,$length, $callback->($retval)
399		481
400	C<aio_readahead> populates the page cache with data from a file so that	482	C<aio_readahead> populates the page cache with data from a file so that
…		…
423		505
424	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	506	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
425	error when stat'ing a large file, the results will be silently truncated	507	error when stat'ing a large file, the results will be silently truncated
426	unless perl itself is compiled with large file support.	508	unless perl itself is compiled with large file support.
427		509
		510	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		511	following constants and functions (if not implemented, the constants will
		512	be C<0> and the functions will either C<croak> or fall back on traditional
		513	behaviour).
		514
		515	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		516	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		517	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		518
428	Example: Print the length of F</etc/passwd>:	519	Example: Print the length of F</etc/passwd>:
429		520
430	aio_stat "/etc/passwd", sub {	521	aio_stat "/etc/passwd", sub {
431	$_[0] and die "stat failed: $!";	522	$_[0] and die "stat failed: $!";
432	print "size is ", -s _, "\n";	523	print "size is ", -s _, "\n";
433	};	524	};
434		525
435		526
		527	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		528
		529	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		530	whether a file handle or path was passed.
		531
		532	On success, the callback is passed a hash reference with the following
		533	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		534	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		535	is passed.
		536
		537	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		538	C<ST_NOSUID>.
		539
		540	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		541	their correct value when available, or to C<0> on systems that do
		542	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		543	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		544	C<ST_NODIRATIME> and C<ST_RELATIME>.
		545
		546	Example: stat C</wd> and dump out the data if successful.
		547
		548	aio_statvfs "/wd", sub {
		549	my $f = $_[0]
		550	or die "statvfs: $!";
		551
		552	use Data::Dumper;
		553	say Dumper $f;
		554	};
		555
		556	# result:
		557	{
		558	bsize => 1024,
		559	bfree => 4333064312,
		560	blocks => 10253828096,
		561	files => 2050765568,
		562	flag => 4096,
		563	favail => 2042092649,
		564	bavail => 4333064312,
		565	ffree => 2042092649,
		566	namemax => 255,
		567	frsize => 1024,
		568	fsid => 1810
		569	}
		570
		571
436	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	572	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
437		573
438	Works like perl's C<utime> function (including the special case of $atime	574	Works like perl's C<utime> function (including the special case of $atime
439	and $mtime being undef). Fractional times are supported if the underlying	575	and $mtime being undef). Fractional times are supported if the underlying
440	syscalls support them.	576	syscalls support them.
…		…
488		624
489	The only (POSIX-) portable way of calling this function is:	625	The only (POSIX-) portable way of calling this function is:
490		626
491	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	627	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
492		628
		629	See C<aio_stat> for info about some potentially helpful extra constants
		630	and functions.
493		631
494	=item aio_link $srcpath, $dstpath, $callback->($status)	632	=item aio_link $srcpath, $dstpath, $callback->($status)
495		633
496	Asynchronously create a new link to the existing object at C<$srcpath> at	634	Asynchronously create a new link to the existing object at C<$srcpath> at
497	the path C<$dstpath> and call the callback with the result code.	635	the path C<$dstpath> and call the callback with the result code.
…		…
508	Asynchronously read the symlink specified by C<$path> and pass it to	646	Asynchronously read the symlink specified by C<$path> and pass it to
509	the callback. If an error occurs, nothing or undef gets passed to the	647	the callback. If an error occurs, nothing or undef gets passed to the
510	callback.	648	callback.
511		649
512		650
		651	=item aio_realpath $path, $callback->($path)
		652
		653	Asynchronously make the path absolute and resolve any symlinks in
		654	C<$path>. The resulting path only consists of directories (Same as
		655	L<Cwd::realpath>).
		656
		657	This request can be used to get the absolute path of the current working
		658	directory by passing it a path of F<.> (a single dot).
		659
		660
513	=item aio_rename $srcpath, $dstpath, $callback->($status)	661	=item aio_rename $srcpath, $dstpath, $callback->($status)
514		662
515	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	663	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
516	rename(2) and call the callback with the result code.	664	rename(2) and call the callback with the result code.
517		665
…		…
533		681
534	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	682	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
535	directory (i.e. opendir + readdir + closedir). The entries will not be	683	directory (i.e. opendir + readdir + closedir). The entries will not be
536	sorted, and will B<NOT> include the C<.> and C<..> entries.	684	sorted, and will B<NOT> include the C<.> and C<..> entries.
537		685
538	The callback a single argument which is either C<undef> or an array-ref	686	The callback is passed a single argument which is either C<undef> or an
539	with the filenames.	687	array-ref with the filenames.
		688
		689
		690	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		691
		692	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
		693	tune behaviour and output format. In case of an error, C<$entries> will be
		694	C<undef>.
		695
		696	The flags are a combination of the following constants, ORed together (the
		697	flags will also be passed to the callback, possibly modified):
		698
		699	=over 4
		700
		701	=item IO::AIO::READDIR_DENTS
		702
		703	When this flag is off, then the callback gets an arrayref consisting of
		704	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		705	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		706	entry in more detail.
		707
		708	C<$name> is the name of the entry.
		709
		710	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		711
		712	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		713	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		714	C<IO::AIO::DT_WHT>.
		715
		716	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		717	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		718	scalars are read-only: you can not modify them.
		719
		720	C<$inode> is the inode number (which might not be exact on systems with 64
		721	bit inode numbers and 32 bit perls). This field has unspecified content on
		722	systems that do not deliver the inode information.
		723
		724	=item IO::AIO::READDIR_DIRS_FIRST
		725
		726	When this flag is set, then the names will be returned in an order where
		727	likely directories come first, in optimal stat order. This is useful when
		728	you need to quickly find directories, or you want to find all directories
		729	while avoiding to stat() each entry.
		730
		731	If the system returns type information in readdir, then this is used
		732	to find directories directly. Otherwise, likely directories are names
		733	beginning with ".", or otherwise names with no dots, of which names with
		734	short names are tried first.
		735
		736	=item IO::AIO::READDIR_STAT_ORDER
		737
		738	When this flag is set, then the names will be returned in an order
		739	suitable for stat()'ing each one. That is, when you plan to stat()
		740	all files in the given directory, then the returned order will likely
		741	be fastest.
		742
		743	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		744	the likely dirs come first, resulting in a less optimal stat order.
		745
		746	=item IO::AIO::READDIR_FOUND_UNKNOWN
		747
		748	This flag should not be set when calling C<aio_readdirx>. Instead, it
		749	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		750	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
		751	C<$type>'s are known, which can be used to speed up some algorithms.
		752
		753	=back
540		754
541		755
542	=item aio_load $path, $data, $callback->($status)	756	=item aio_load $path, $data, $callback->($status)
543		757
544	This is a composite request that tries to fully load the given file into	758	This is a composite request that tries to fully load the given file into
…		…
569		783
570	=item aio_copy $srcpath, $dstpath, $callback->($status)	784	=item aio_copy $srcpath, $dstpath, $callback->($status)
571		785
572	Try to copy the I<file> (directories not supported as either source or	786	Try to copy the I<file> (directories not supported as either source or
573	destination) from C<$srcpath> to C<$dstpath> and call the callback with	787	destination) from C<$srcpath> to C<$dstpath> and call the callback with
574	the C<0> (error) or C<-1> ok.	788	a status of C<0> (ok) or C<-1> (error, see C<$!>).
575		789
576	This is a composite request that creates the destination file with	790	This is a composite request that creates the destination file with
577	mode 0200 and copies the contents of the source file into it using	791	mode 0200 and copies the contents of the source file into it using
578	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	792	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
579	uid/gid, in that order.	793	uid/gid, in that order.
…		…
591	my $grp = aio_group $cb;	805	my $grp = aio_group $cb;
592		806
593	aioreq_pri $pri;	807	aioreq_pri $pri;
594	add $grp aio_open $src, O_RDONLY, 0, sub {	808	add $grp aio_open $src, O_RDONLY, 0, sub {
595	if (my $src_fh = $_[0]) {	809	if (my $src_fh = $_[0]) {
596	my @stat = stat $src_fh; # hmm, might bock over nfs?	810	my @stat = stat $src_fh; # hmm, might block over nfs?
597		811
598	aioreq_pri $pri;	812	aioreq_pri $pri;
599	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	813	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
600	if (my $dst_fh = $_[0]) {	814	if (my $dst_fh = $_[0]) {
601	aioreq_pri $pri;	815	aioreq_pri $pri;
…		…
648		862
649	=item aio_move $srcpath, $dstpath, $callback->($status)	863	=item aio_move $srcpath, $dstpath, $callback->($status)
650		864
651	Try to move the I<file> (directories not supported as either source or	865	Try to move the I<file> (directories not supported as either source or
652	destination) from C<$srcpath> to C<$dstpath> and call the callback with	866	destination) from C<$srcpath> to C<$dstpath> and call the callback with
653	the C<0> (error) or C<-1> ok.	867	a status of C<0> (ok) or C<-1> (error, see C<$!>).
654		868
655	This is a composite request that tries to rename(2) the file first; if	869	This is a composite request that tries to rename(2) the file first; if
656	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if	870	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
657	that is successful, unlinks the C<$srcpath>.	871	that is successful, unlinks the C<$srcpath>.
658		872
…		…
669	if ($_[0] && $! == EXDEV) {	883	if ($_[0] && $! == EXDEV) {
670	aioreq_pri $pri;	884	aioreq_pri $pri;
671	add $grp aio_copy $src, $dst, sub {	885	add $grp aio_copy $src, $dst, sub {
672	$grp->result ($_[0]);	886	$grp->result ($_[0]);
673		887
674	if (!$_[0]) {	888	unless ($_[0]) {
675	aioreq_pri $pri;	889	aioreq_pri $pri;
676	add $grp aio_unlink $src;	890	add $grp aio_unlink $src;
677	}	891	}
678	};	892	};
679	} else {	893	} else {
…		…
709		923
710	Implementation notes.	924	Implementation notes.
711		925
712	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	926	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
713		927
		928	If readdir returns file type information, then this is used directly to
		929	find directories.
		930
714	After reading the directory, the modification time, size etc. of the	931	Otherwise, after reading the directory, the modification time, size etc.
715	directory before and after the readdir is checked, and if they match (and	932	of the directory before and after the readdir is checked, and if they
716	isn't the current time), the link count will be used to decide how many	933	match (and isn't the current time), the link count will be used to decide
717	entries are directories (if >= 2). Otherwise, no knowledge of the number	934	how many entries are directories (if >= 2). Otherwise, no knowledge of the
718	of subdirectories will be assumed.	935	number of subdirectories will be assumed.
719		936
720	Then entries will be sorted into likely directories (everything without	937	Then entries will be sorted into likely directories a non-initial dot
721	a non-initial dot currently) and likely non-directories (everything	938	currently) and likely non-directories (see C<aio_readdirx>). Then every
722	else). Then every entry plus an appended C</.> will be C<stat>'ed,	939	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
723	likely directories first. If that succeeds, it assumes that the entry	940	in order of their inode numbers. If that succeeds, it assumes that the
724	is a directory or a symlink to directory (which will be checked	941	entry is a directory or a symlink to directory (which will be checked
725	seperately). This is often faster than stat'ing the entry itself because	942	separately). This is often faster than stat'ing the entry itself because
726	filesystems might detect the type of the entry without reading the inode	943	filesystems might detect the type of the entry without reading the inode
727	data (e.g. ext2fs filetype feature).	944	data (e.g. ext2fs filetype feature), even on systems that cannot return
		945	the filetype information on readdir.
728		946
729	If the known number of directories (link count - 2) has been reached, the	947	If the known number of directories (link count - 2) has been reached, the
730	rest of the entries is assumed to be non-directories.	948	rest of the entries is assumed to be non-directories.
731		949
732	This only works with certainty on POSIX (= UNIX) filesystems, which	950	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
754	my $now = time;	972	my $now = time;
755	my $hash1 = join ":", (stat _)[0,1,3,7,9];	973	my $hash1 = join ":", (stat _)[0,1,3,7,9];
756		974
757	# read the directory entries	975	# read the directory entries
758	aioreq_pri $pri;	976	aioreq_pri $pri;
759	add $grp aio_readdir $path, sub {	977	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
760	my $entries = shift	978	my $entries = shift
761	or return $grp->result ();	979	or return $grp->result ();
762		980
763	# stat the dir another time	981	# stat the dir another time
764	aioreq_pri $pri;	982	aioreq_pri $pri;
…		…
770	# take the slow route if anything looks fishy	988	# take the slow route if anything looks fishy
771	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	989	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
772	$ndirs = -1;	990	$ndirs = -1;
773	} else {	991	} else {
774	# if nlink == 2, we are finished	992	# if nlink == 2, we are finished
775	# on non-posix-fs's, we rely on nlink < 2	993	# for non-posix-fs's, we rely on nlink < 2
776	$ndirs = (stat _)[3] - 2	994	$ndirs = (stat _)[3] - 2
777	or return $grp->result ([], $entries);	995	or return $grp->result ([], $entries);
778	}	996	}
779		997
780	# sort into likely dirs and likely nondirs
781	# dirs == files without ".", short entries first
782	$entries = [map $_->[0],
783	sort { $b->[1] cmp $a->[1] }
784	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
785	@$entries];
786
787	my (@dirs, @nondirs);	998	my (@dirs, @nondirs);
788		999
789	my $statgrp = add $grp aio_group sub {	1000	my $statgrp = add $grp aio_group sub {
790	$grp->result (\@dirs, \@nondirs);	1001	$grp->result (\@dirs, \@nondirs);
791	};	1002	};
792		1003
793	limit $statgrp $maxreq;	1004	limit $statgrp $maxreq;
794	feed $statgrp sub {	1005	feed $statgrp sub {
795	return unless @$entries;	1006	return unless @$entries;
796	my $entry = pop @$entries;	1007	my $entry = shift @$entries;
797		1008
798	aioreq_pri $pri;	1009	aioreq_pri $pri;
799	add $statgrp aio_stat "$path/$entry/.", sub {	1010	add $statgrp aio_stat "$path/$entry/.", sub {
800	if ($_[0] < 0) {	1011	if ($_[0] < 0) {
801	push @nondirs, $entry;	1012	push @nondirs, $entry;
…		…
874	callback with the fdatasync result code.	1085	callback with the fdatasync result code.
875		1086
876	If this call isn't available because your OS lacks it or it couldn't be	1087	If this call isn't available because your OS lacks it or it couldn't be
877	detected, it will be emulated by calling C<fsync> instead.	1088	detected, it will be emulated by calling C<fsync> instead.
878		1089
		1090	=item aio_syncfs $fh, $callback->($status)
		1091
		1092	Asynchronously call the syncfs syscall to sync the filesystem associated
		1093	to the given filehandle and call the callback with the syncfs result
		1094	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1095	errno to C<ENOSYS> nevertheless.
		1096
879	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1097	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
880		1098
881	Sync the data portion of the file specified by C<$offset> and C<$length>	1099	Sync the data portion of the file specified by C<$offset> and C<$length>
882	to disk (but NOT the metadata), by calling the Linux-specific	1100	to disk (but NOT the metadata), by calling the Linux-specific
883	sync_file_range call. If sync_file_range is not available or it returns	1101	sync_file_range call. If sync_file_range is not available or it returns
…		…
894	composite request intended to sync directories after directory operations	1112	composite request intended to sync directories after directory operations
895	(E.g. rename). This might not work on all operating systems or have any	1113	(E.g. rename). This might not work on all operating systems or have any
896	specific effect, but usually it makes sure that directory changes get	1114	specific effect, but usually it makes sure that directory changes get
897	written to disc. It works for anything that can be opened for read-only,	1115	written to disc. It works for anything that can be opened for read-only,
898	not just directories.	1116	not just directories.
		1117
		1118	Future versions of this function might fall back to other methods when
		1119	C<fsync> on the directory fails (such as calling C<sync>).
899		1120
900	Passes C<0> when everything went ok, and C<-1> on error.	1121	Passes C<0> when everything went ok, and C<-1> on error.
901		1122
902	=cut	1123	=cut
903		1124
…		…
924	};	1145	};
925		1146
926	$grp	1147	$grp
927	}	1148	}
928		1149
		1150	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1151
		1152	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1153	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1154	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1155	scalar must only be modified in-place while an aio operation is pending on
		1156	it).
		1157
		1158	It calls the C<msync> function of your OS, if available, with the memory
		1159	area starting at C<$offset> in the string and ending C<$length> bytes
		1160	later. If C<$length> is negative, counts from the end, and if C<$length>
		1161	is C<undef>, then it goes till the end of the string. The flags can be
		1162	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1163	C<IO::AIO::MS_SYNC>.
		1164
		1165	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1166
		1167	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1168	scalars.
		1169
		1170	It touches (reads or writes) all memory pages in the specified
		1171	range inside the scalar. All caveats and parameters are the same
		1172	as for C<aio_msync>, above, except for flags, which must be either
		1173	C<0> (which reads all pages and ensures they are instantiated) or
		1174	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1175	writing an octet from it, which dirties the page).
		1176
		1177	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1178
		1179	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1180	scalars.
		1181
		1182	It reads in all the pages of the underlying storage into memory (if any)
		1183	and locks them, so they are not getting swapped/paged out or removed.
		1184
		1185	If C<$length> is undefined, then the scalar will be locked till the end.
		1186
		1187	On systems that do not implement C<mlock>, this function returns C<-1>
		1188	and sets errno to C<ENOSYS>.
		1189
		1190	Note that the corresponding C<munlock> is synchronous and is
		1191	documented under L<MISCELLANEOUS FUNCTIONS>.
		1192
		1193	Example: open a file, mmap and mlock it - both will be undone when
		1194	C<$data> gets destroyed.
		1195
		1196	open my $fh, "<", $path or die "$path: $!";
		1197	my $data;
		1198	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1199	aio_mlock $data; # mlock in background
		1200
		1201	=item aio_mlockall $flags, $callback->($status)
		1202
		1203	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1204	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1205
		1206	On systems that do not implement C<mlockall>, this function returns C<-1>
		1207	and sets errno to C<ENOSYS>.
		1208
		1209	Note that the corresponding C<munlockall> is synchronous and is
		1210	documented under L<MISCELLANEOUS FUNCTIONS>.
		1211
		1212	Example: asynchronously lock all current and future pages into memory.
		1213
		1214	aio_mlockall IO::AIO::MCL_FUTURE;
		1215
929	=item aio_group $callback->(...)	1216	=item aio_group $callback->(...)
930		1217
931	This is a very special aio request: Instead of doing something, it is a	1218	This is a very special aio request: Instead of doing something, it is a
932	container for other aio requests, which is useful if you want to bundle	1219	container for other aio requests, which is useful if you want to bundle
933	many requests into a single, composite, request with a definite callback	1220	many requests into a single, composite, request with a definite callback
…		…
982	=item cancel $req	1269	=item cancel $req
983		1270
984	Cancels the request, if possible. Has the effect of skipping execution	1271	Cancels the request, if possible. Has the effect of skipping execution
985	when entering the B<execute> state and skipping calling the callback when	1272	when entering the B<execute> state and skipping calling the callback when
986	entering the the B<result> state, but will leave the request otherwise	1273	entering the the B<result> state, but will leave the request otherwise
987	untouched. That means that requests that currently execute will not be	1274	untouched (with the exception of readdir). That means that requests that
988	stopped and resources held by the request will not be freed prematurely.	1275	currently execute will not be stopped and resources held by the request
		1276	will not be freed prematurely.
989		1277
990	=item cb $req $callback->(...)	1278	=item cb $req $callback->(...)
991		1279
992	Replace (or simply set) the callback registered to the request.	1280	Replace (or simply set) the callback registered to the request.
993		1281
…		…
1066		1354
1067	=item $grp->cancel_subs	1355	=item $grp->cancel_subs
1068		1356
1069	Cancel all subrequests and clears any feeder, but not the group request	1357	Cancel all subrequests and clears any feeder, but not the group request
1070	itself. Useful when you queued a lot of events but got a result early.	1358	itself. Useful when you queued a lot of events but got a result early.
		1359
		1360	The group request will finish normally (you cannot add requests to the
		1361	group).
1071		1362
1072	=item $grp->result (...)	1363	=item $grp->result (...)
1073		1364
1074	Set the result value(s) that will be passed to the group callback when all	1365	Set the result value(s) that will be passed to the group callback when all
1075	subrequests have finished and set the groups errno to the current value	1366	subrequests have finished and set the groups errno to the current value
…		…
1144	=over 4	1435	=over 4
1145		1436
1146	=item $fileno = IO::AIO::poll_fileno	1437	=item $fileno = IO::AIO::poll_fileno
1147		1438
1148	Return the I<request result pipe file descriptor>. This filehandle must be	1439	Return the I<request result pipe file descriptor>. This filehandle must be
1149	polled for reading by some mechanism outside this module (e.g. Event or	1440	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1150	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1441	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1151	to call C<poll_cb> to check the results.	1442	you have to call C<poll_cb> to check the results.
1152		1443
1153	See C<poll_cb> for an example.	1444	See C<poll_cb> for an example.
1154		1445
1155	=item IO::AIO::poll_cb	1446	=item IO::AIO::poll_cb
1156		1447
1157	Process some outstanding events on the result pipe. You have to call this	1448	Process some outstanding events on the result pipe. You have to call
1158	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1449	this regularly. Returns C<0> if all events could be processed (or there
1159	returned earlier for whatever reason. Returns immediately when no events	1450	were no events to process), or C<-1> if it returned earlier for whatever
1160	are outstanding. The amount of events processed depends on the settings of	1451	reason. Returns immediately when no events are outstanding. The amount of
1161	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1452	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1453	C<IO::AIO::max_poll_time>.
1162		1454
1163	If not all requests were processed for whatever reason, the filehandle	1455	If not all requests were processed for whatever reason, the filehandle
1164	will still be ready when C<poll_cb> returns, so normally you don't have to	1456	will still be ready when C<poll_cb> returns, so normally you don't have to
1165	do anything special to have it called later.	1457	do anything special to have it called later.
1166		1458
		1459	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1460	ready, it can be beneficial to call this function from loops which submit
		1461	a lot of requests, to make sure the results get processed when they become
		1462	available and not just when the loop is finished and the event loop takes
		1463	over again. This function returns very fast when there are no outstanding
		1464	requests.
		1465
1167	Example: Install an Event watcher that automatically calls	1466	Example: Install an Event watcher that automatically calls
1168	IO::AIO::poll_cb with high priority:	1467	IO::AIO::poll_cb with high priority (more examples can be found in the
		1468	SYNOPSIS section, at the top of this document):
1169		1469
1170	Event->io (fd => IO::AIO::poll_fileno,	1470	Event->io (fd => IO::AIO::poll_fileno,
1171	poll => 'r', async => 1,	1471	poll => 'r', async => 1,
1172	cb => \&IO::AIO::poll_cb);	1472	cb => \&IO::AIO::poll_cb);
		1473
		1474	=item IO::AIO::poll_wait
		1475
		1476	If there are any outstanding requests and none of them in the result
		1477	phase, wait till the result filehandle becomes ready for reading (simply
		1478	does a C<select> on the filehandle. This is useful if you want to
		1479	synchronously wait for some requests to finish).
		1480
		1481	See C<nreqs> for an example.
		1482
		1483	=item IO::AIO::poll
		1484
		1485	Waits until some requests have been handled.
		1486
		1487	Returns the number of requests processed, but is otherwise strictly
		1488	equivalent to:
		1489
		1490	IO::AIO::poll_wait, IO::AIO::poll_cb
		1491
		1492	=item IO::AIO::flush
		1493
		1494	Wait till all outstanding AIO requests have been handled.
		1495
		1496	Strictly equivalent to:
		1497
		1498	IO::AIO::poll_wait, IO::AIO::poll_cb
		1499	while IO::AIO::nreqs;
1173		1500
1174	=item IO::AIO::max_poll_reqs $nreqs	1501	=item IO::AIO::max_poll_reqs $nreqs
1175		1502
1176	=item IO::AIO::max_poll_time $seconds	1503	=item IO::AIO::max_poll_time $seconds
1177		1504
…		…
1202	# use a low priority so other tasks have priority	1529	# use a low priority so other tasks have priority
1203	Event->io (fd => IO::AIO::poll_fileno,	1530	Event->io (fd => IO::AIO::poll_fileno,
1204	poll => 'r', nice => 1,	1531	poll => 'r', nice => 1,
1205	cb => &IO::AIO::poll_cb);	1532	cb => &IO::AIO::poll_cb);
1206		1533
1207	=item IO::AIO::poll_wait
1208
1209	If there are any outstanding requests and none of them in the result
1210	phase, wait till the result filehandle becomes ready for reading (simply
1211	does a C<select> on the filehandle. This is useful if you want to
1212	synchronously wait for some requests to finish).
1213
1214	See C<nreqs> for an example.
1215
1216	=item IO::AIO::poll
1217
1218	Waits until some requests have been handled.
1219
1220	Returns the number of requests processed, but is otherwise strictly
1221	equivalent to:
1222
1223	IO::AIO::poll_wait, IO::AIO::poll_cb
1224
1225	=item IO::AIO::flush
1226
1227	Wait till all outstanding AIO requests have been handled.
1228
1229	Strictly equivalent to:
1230
1231	IO::AIO::poll_wait, IO::AIO::poll_cb
1232	while IO::AIO::nreqs;
1233
1234	=back	1534	=back
1235		1535
1236	=head3 CONTROLLING THE NUMBER OF THREADS	1536	=head3 CONTROLLING THE NUMBER OF THREADS
1237		1537
1238	=over	1538	=over
…		…
1271		1571
1272	Under normal circumstances you don't need to call this function.	1572	Under normal circumstances you don't need to call this function.
1273		1573
1274	=item IO::AIO::max_idle $nthreads	1574	=item IO::AIO::max_idle $nthreads
1275		1575
1276	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1576	Limit the number of threads (default: 4) that are allowed to idle
1277	threads that did not get a request to process within 10 seconds). That	1577	(i.e., threads that did not get a request to process within the idle
1278	means if a thread becomes idle while C<$nthreads> other threads are also	1578	timeout (default: 10 seconds). That means if a thread becomes idle while
1279	idle, it will free its resources and exit.	1579	C<$nthreads> other threads are also idle, it will free its resources and
		1580	exit.
1280		1581
1281	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1582	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1282	to allow for extremely high load situations, but want to free resources	1583	to allow for extremely high load situations, but want to free resources
1283	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1584	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1284		1585
1285	The default is probably ok in most situations, especially if thread	1586	The default is probably ok in most situations, especially if thread
1286	creation is fast. If thread creation is very slow on your system you might	1587	creation is fast. If thread creation is very slow on your system you might
1287	want to use larger values.	1588	want to use larger values.
1288		1589
		1590	=item IO::AIO::idle_timeout $seconds
		1591
		1592	Sets the minimum idle timeout (default 10) after which worker threads are
		1593	allowed to exit. SEe C<IO::AIO::max_idle>.
		1594
1289	=item IO::AIO::max_outstanding $maxreqs	1595	=item IO::AIO::max_outstanding $maxreqs
		1596
		1597	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1598	you do queue up more than this number of requests, the next call to
		1599	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1600	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1601	longer exceeded.
		1602
		1603	In other words, this setting does not enforce a queue limit, but can be
		1604	used to make poll functions block if the limit is exceeded.
1290		1605
1291	This is a very bad function to use in interactive programs because it	1606	This is a very bad function to use in interactive programs because it
1292	blocks, and a bad way to reduce concurrency because it is inexact: Better	1607	blocks, and a bad way to reduce concurrency because it is inexact: Better
1293	use an C<aio_group> together with a feed callback.	1608	use an C<aio_group> together with a feed callback.
1294		1609
1295	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1610	It's main use is in scripts without an event loop - when you want to stat
1296	do queue up more than this number of requests, the next call to the	1611	a lot of files, you can write somehting like this:
1297	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1298	function will block until the limit is no longer exceeded.
1299		1612
1300	The default value is very large, so there is no practical limit on the	1613	IO::AIO::max_outstanding 32;
1301	number of outstanding requests.
1302		1614
1303	You can still queue as many requests as you want. Therefore,	1615	for my $path (...) {
1304	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1616	aio_stat $path , ...;
1305	as a stop gap to shield against fatal memory overflow (with large values).	1617	IO::AIO::poll_cb;
		1618	}
		1619
		1620	IO::AIO::flush;
		1621
		1622	The call to C<poll_cb> inside the loop will normally return instantly, but
		1623	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1624	some requests have been handled. This keeps the loop from pushing a large
		1625	number of C<aio_stat> requests onto the queue.
		1626
		1627	The default value for C<max_outstanding> is very large, so there is no
		1628	practical limit on the number of outstanding requests.
1306		1629
1307	=back	1630	=back
1308		1631
1309	=head3 STATISTICAL INFORMATION	1632	=head3 STATISTICAL INFORMATION
1310		1633
…		…
1330	Returns the number of requests currently in the pending state (executed,	1653	Returns the number of requests currently in the pending state (executed,
1331	but not yet processed by poll_cb).	1654	but not yet processed by poll_cb).
1332		1655
1333	=back	1656	=back
1334		1657
		1658	=head3 MISCELLANEOUS FUNCTIONS
		1659
		1660	IO::AIO implements some functions that might be useful, but are not
		1661	asynchronous.
		1662
		1663	=over 4
		1664
		1665	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1666
		1667	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1668	but is blocking (this makes most sense if you know the input data is
		1669	likely cached already and the output filehandle is set to non-blocking
		1670	operations).
		1671
		1672	Returns the number of bytes copied, or C<-1> on error.
		1673
		1674	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1675
		1676	Simply calls the C<posix_fadvise> function (see its
		1677	manpage for details). The following advice constants are
		1678	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1679	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1680	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1681
		1682	On systems that do not implement C<posix_fadvise>, this function returns
		1683	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1684
		1685	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1686
		1687	Simply calls the C<posix_madvise> function (see its
		1688	manpage for details). The following advice constants are
		1689	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1690	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1691
		1692	On systems that do not implement C<posix_madvise>, this function returns
		1693	ENOSYS, otherwise the return value of C<posix_madvise>.
		1694
		1695	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1696
		1697	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1698	$scalar (see its manpage for details). The following protect
		1699	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1700	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1701
		1702	On systems that do not implement C<mprotect>, this function returns
		1703	ENOSYS, otherwise the return value of C<mprotect>.
		1704
		1705	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1706
		1707	Memory-maps a file (or anonymous memory range) and attaches it to the
		1708	given C<$scalar>, which will act like a string scalar.
		1709
		1710	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1711	change the string length, and most read-only operations such as copying it
		1712	or searching it with regexes and so on.
		1713
		1714	Anything else is unsafe and will, at best, result in memory leaks.
		1715
		1716	The memory map associated with the C<$scalar> is automatically removed
		1717	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1718	C<IO::AIO::munmap> functions are called.
		1719
		1720	This calls the C<mmap>(2) function internally. See your system's manual
		1721	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1722
		1723	The C<$length> must be larger than zero and smaller than the actual
		1724	filesize.
		1725
		1726	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1727	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1728
		1729	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1730	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1731	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1732	(which is set to C<MAP_ANON> if your system only provides this
		1733	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1734	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1735	C<IO::AIO::MAP_NONBLOCK>
		1736
		1737	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1738
		1739	C<$offset> is the offset from the start of the file - it generally must be
		1740	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1741
		1742	Example:
		1743
		1744	use Digest::MD5;
		1745	use IO::AIO;
		1746
		1747	open my $fh, "<verybigfile"
		1748	or die "$!";
		1749
		1750	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1751	or die "verybigfile: $!";
		1752
		1753	my $fast_md5 = md5 $data;
		1754
		1755	=item IO::AIO::munmap $scalar
		1756
		1757	Removes a previous mmap and undefines the C<$scalar>.
		1758
		1759	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1760
		1761	Calls the C<munlock> function, undoing the effects of a previous
		1762	C<aio_mlock> call (see its description for details).
		1763
		1764	=item IO::AIO::munlockall
		1765
		1766	Calls the C<munlockall> function.
		1767
		1768	On systems that do not implement C<munlockall>, this function returns
		1769	ENOSYS, otherwise the return value of C<munlockall>.
		1770
		1771	=back
		1772
1335	=cut	1773	=cut
1336		1774
1337	min_parallel 8;	1775	min_parallel 8;
1338		1776
1339	END { flush }	1777	END { flush }
1340		1778
1341	1;	1779	1;
1342		1780
		1781	=head1 EVENT LOOP INTEGRATION
		1782
		1783	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1784	automatically into many event loops:
		1785
		1786	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1787	use AnyEvent::AIO;
		1788
		1789	You can also integrate IO::AIO manually into many event loops, here are
		1790	some examples of how to do this:
		1791
		1792	# EV integration
		1793	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1794
		1795	# Event integration
		1796	Event->io (fd => IO::AIO::poll_fileno,
		1797	poll => 'r',
		1798	cb => \&IO::AIO::poll_cb);
		1799
		1800	# Glib/Gtk2 integration
		1801	add_watch Glib::IO IO::AIO::poll_fileno,
		1802	in => sub { IO::AIO::poll_cb; 1 };
		1803
		1804	# Tk integration
		1805	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1806	readable => \&IO::AIO::poll_cb);
		1807
		1808	# Danga::Socket integration
		1809	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1810	\&IO::AIO::poll_cb);
		1811
1343	=head2 FORK BEHAVIOUR	1812	=head2 FORK BEHAVIOUR
1344		1813
1345	This module should do "the right thing" when the process using it forks:	1814	Usage of pthreads in a program changes the semantics of fork
		1815	considerably. Specifically, only async-safe functions can be called after
		1816	fork. Perl doesn't know about this, so in general, you cannot call fork
		1817	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		1818	pthreads, so this applies, but many other extensions and (for inexplicable
		1819	reasons) perl itself often is linked against pthreads, so this limitation
		1820	applies to quite a lot of perls.
1346		1821
1347	Before the fork, IO::AIO enters a quiescent state where no requests	1822	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1348	can be added in other threads and no results will be processed. After	1823	only works in the process that loaded it. Forking is fully supported, but
1349	the fork the parent simply leaves the quiescent state and continues	1824	using IO::AIO in the child is not.
1350	request/result processing, while the child frees the request/result queue
1351	(so that the requests started before the fork will only be handled in the
1352	parent). Threads will be started on demand until the limit set in the
1353	parent process has been reached again.
1354		1825
1355	In short: the parent will, after a short pause, continue as if fork had	1826	You might get around by not I<using> IO::AIO before (or after)
1356	not been called, while the child will act as if IO::AIO has not been used	1827	forking. You could also try to call the L<IO::AIO::reinit> function in the
1357	yet.	1828	child:
		1829
		1830	=over 4
		1831
		1832	=item IO::AIO::reinit
		1833
		1834	Abandons all current requests and I/O threads and simply reinitialises all
		1835	data structures. This is not an operation supported by any standards, but
		1836	happens to work on GNU/Linux and some newer BSD systems.
		1837
		1838	The only reasonable use for this function is to call it after forking, if
		1839	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1840	the process will result in undefined behaviour. Calling it at any time
		1841	will also result in any undefined (by POSIX) behaviour.
		1842
		1843	=back
1358		1844
1359	=head2 MEMORY USAGE	1845	=head2 MEMORY USAGE
1360		1846
1361	Per-request usage:	1847	Per-request usage:
1362		1848

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs. Revision 1.207 by root, Mon Jul 25 16:50:33 2011 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.147 by root, Wed Jun 3 12:24:49 2009 UTC vs.
Revision 1.207 by root, Mon Jul 25 16:50:33 2011 UTC