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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC vs.
Revision 1.274 by root, Thu Sep 21 23:43:46 2017 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	IO::AIO - Asynchronous Input/Output	3	IO::AIO - Asynchronous/Advanced Input/Output
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
58	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
59	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
60	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
61	using threads anyway.	61	using threads anyway.
62		62
		63	In addition to asynchronous I/O, this module also exports some rather
		64	arcane interfaces, such as C<madvise> or linux's C<splice> system call,
		65	which is why the C<A> in C<AIO> can also mean I<advanced>.
		66
63	Although the module will work in the presence of other (Perl-) threads,	67	Although the module will work in the presence of other (Perl-) threads,
64	it is currently not reentrant in any way, so use appropriate locking	68	it is currently not reentrant in any way, so use appropriate locking
65	yourself, always call C<poll_cb> from within the same thread, or never	69	yourself, always call C<poll_cb> from within the same thread, or never
66	call C<poll_cb> (or other C<aio_> functions) recursively.	70	call C<poll_cb> (or other C<aio_> functions) recursively.
67		71
68	=head2 EXAMPLE	72	=head2 EXAMPLE
69		73
70	This is a simple example that uses the EV module and loads	74	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	75	F</etc/passwd> asynchronously:
72		76
73	use Fcntl;
74	use EV;	77	use EV;
75	use IO::AIO;	78	use IO::AIO;
76		79
77	# register the IO::AIO callback with EV	80	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	81	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		98
96	# file contents now in $contents	99	# file contents now in $contents
97	print $contents;	100	print $contents;
98		101
99	# exit event loop and program	102	# exit event loop and program
100	EV::unloop;	103	EV::break;
101	};	104	};
102	};	105	};
103		106
104	# possibly queue up other requests, or open GUI windows,	107	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	108	# check for sockets etc. etc.
106		109
107	# process events as long as there are some:	110	# process events as long as there are some:
108	EV::loop;	111	EV::run;
109		112
110	=head1 REQUEST ANATOMY AND LIFETIME	113	=head1 REQUEST ANATOMY AND LIFETIME
111		114
112	Every C<aio_*> function creates a request. which is a C data structure not	115	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	116	directly visible to Perl.
…		…
168	use common::sense;	171	use common::sense;
169		172
170	use base 'Exporter';	173	use base 'Exporter';
171		174
172	BEGIN {	175	BEGIN {
173	our $VERSION = '4.0';	176	our $VERSION = 4.35;
174		177
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	178	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	179	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179	aio_pathsync aio_readahead	182	aio_pathsync aio_readahead aio_fiemap aio_allocate
180	aio_rename aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs	187	aio_statvfs
185	aio_wd);	188	aio_wd);
…		…
202		205
203	=head1 FUNCTIONS	206	=head1 FUNCTIONS
204		207
205	=head2 QUICK OVERVIEW	208	=head2 QUICK OVERVIEW
206		209
207	This section simply lists the prototypes of the most important functions	210	This section simply lists the prototypes most of the functions for
208	for quick reference. See the following sections for function-by-function	211	quick reference. See the following sections for function-by-function
209	documentation.	212	documentation.
210		213
211	aio_wd $pathname, $callback->($wd)	214	aio_wd $pathname, $callback->($wd)
212	aio_open $pathname, $flags, $mode, $callback->($fh)	215	aio_open $pathname, $flags, $mode, $callback->($fh)
213	aio_close $fh, $callback->($status)	216	aio_close $fh, $callback->($status)
		217	aio_seek $fh,$offset,$whence, $callback->($offs)
214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	218	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	219	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	220	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217	aio_readahead $fh,$offset,$length, $callback->($retval)	221	aio_readahead $fh,$offset,$length, $callback->($retval)
218	aio_stat $fh_or_path, $callback->($status)	222	aio_stat $fh_or_path, $callback->($status)
219	aio_lstat $fh, $callback->($status)	223	aio_lstat $fh, $callback->($status)
220	aio_statvfs $fh_or_path, $callback->($statvfs)	224	aio_statvfs $fh_or_path, $callback->($statvfs)
221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	225	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	226	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		227	aio_chmod $fh_or_path, $mode, $callback->($status)
223	aio_truncate $fh_or_path, $offset, $callback->($status)	228	aio_truncate $fh_or_path, $offset, $callback->($status)
224	aio_chmod $fh_or_path, $mode, $callback->($status)	229	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		230	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225	aio_unlink $pathname, $callback->($status)	231	aio_unlink $pathname, $callback->($status)
226	aio_mknod $pathname, $mode, $dev, $callback->($status)	232	aio_mknod $pathname, $mode, $dev, $callback->($status)
227	aio_link $srcpath, $dstpath, $callback->($status)	233	aio_link $srcpath, $dstpath, $callback->($status)
228	aio_symlink $srcpath, $dstpath, $callback->($status)	234	aio_symlink $srcpath, $dstpath, $callback->($status)
229	aio_readlink $pathname, $callback->($link)	235	aio_readlink $pathname, $callback->($link)
230	aio_realpath $pathname, $callback->($link)	236	aio_realpath $pathname, $callback->($path)
231	aio_rename $srcpath, $dstpath, $callback->($status)	237	aio_rename $srcpath, $dstpath, $callback->($status)
		238	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
232	aio_mkdir $pathname, $mode, $callback->($status)	239	aio_mkdir $pathname, $mode, $callback->($status)
233	aio_rmdir $pathname, $callback->($status)	240	aio_rmdir $pathname, $callback->($status)
234	aio_readdir $pathname, $callback->($entries)	241	aio_readdir $pathname, $callback->($entries)
235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	242	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	243	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	244	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		245	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238	aio_load $pathname, $data, $callback->($status)	246	aio_load $pathname, $data, $callback->($status)
239	aio_copy $srcpath, $dstpath, $callback->($status)	247	aio_copy $srcpath, $dstpath, $callback->($status)
240	aio_move $srcpath, $dstpath, $callback->($status)	248	aio_move $srcpath, $dstpath, $callback->($status)
241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242	aio_rmtree $pathname, $callback->($status)	249	aio_rmtree $pathname, $callback->($status)
		250	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		251	aio_ioctl $fh, $request, $buf, $callback->($status)
243	aio_sync $callback->($status)	252	aio_sync $callback->($status)
244	aio_syncfs $fh, $callback->($status)	253	aio_syncfs $fh, $callback->($status)
245	aio_fsync $fh, $callback->($status)	254	aio_fsync $fh, $callback->($status)
246	aio_fdatasync $fh, $callback->($status)	255	aio_fdatasync $fh, $callback->($status)
247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	256	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248	aio_pathsync $pathname, $callback->($status)	257	aio_pathsync $pathname, $callback->($status)
249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	258	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	260	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252	aio_mlockall $flags, $callback->($status)	261	aio_mlockall $flags, $callback->($status)
253	aio_group $callback->(...)	262	aio_group $callback->(...)
254	aio_nop $callback->()	263	aio_nop $callback->()
…		…
271	IO::AIO::nready	280	IO::AIO::nready
272	IO::AIO::npending	281	IO::AIO::npending
273		282
274	IO::AIO::sendfile $ofh, $ifh, $offset, $count	283	IO::AIO::sendfile $ofh, $ifh, $offset, $count
275	IO::AIO::fadvise $fh, $offset, $len, $advice	284	IO::AIO::fadvise $fh, $offset, $len, $advice
		285	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		286	IO::AIO::munmap $scalar
276	IO::AIO::madvise $scalar, $offset, $length, $advice	287	IO::AIO::madvise $scalar, $offset, $length, $advice
277	IO::AIO::mprotect $scalar, $offset, $length, $protect	288	IO::AIO::mprotect $scalar, $offset, $length, $protect
278	IO::AIO::munlock $scalar, $offset = 0, $length = undef	289	IO::AIO::munlock $scalar, $offset = 0, $length = undef
279	IO::AIO::munlockall	290	IO::AIO::munlockall
280		291
281	=head2 AIO REQUEST FUNCTIONS	292	=head2 API NOTES
282		293
283	All the C<aio_*> calls are more or less thin wrappers around the syscall	294	All the C<aio_*> calls are more or less thin wrappers around the syscall
284	with the same name (sans C<aio_>). The arguments are similar or identical,	295	with the same name (sans C<aio_>). The arguments are similar or identical,
285	and they all accept an additional (and optional) C<$callback> argument	296	and they all accept an additional (and optional) C<$callback> argument
286	which must be a code reference. This code reference will be called after	297	which must be a code reference. This code reference will be called after
…		…
317	correct contents.	328	correct contents.
318		329
319	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	330	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
320	handles correctly whether it is set or not.	331	handles correctly whether it is set or not.
321		332
		333	=head2 AIO REQUEST FUNCTIONS
		334
322	=over 4	335	=over 4
323		336
324	=item $prev_pri = aioreq_pri [$pri]	337	=item $prev_pri = aioreq_pri [$pri]
325		338
326	Returns the priority value that would be used for the next request and, if	339	Returns the priority value that would be used for the next request and, if
…		…
355		368
356		369
357	=item aio_open $pathname, $flags, $mode, $callback->($fh)	370	=item aio_open $pathname, $flags, $mode, $callback->($fh)
358		371
359	Asynchronously open or create a file and call the callback with a newly	372	Asynchronously open or create a file and call the callback with a newly
360	created filehandle for the file.	373	created filehandle for the file (or C<undef> in case of an error).
361		374
362	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	375	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
363	for an explanation.	376	for an explanation.
364		377
365	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	378	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
388	following POSIX and non-POSIX constants are available (missing ones on	401	following POSIX and non-POSIX constants are available (missing ones on
389	your system are, as usual, C<0>):	402	your system are, as usual, C<0>):
390		403
391	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	404	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
392	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	405	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
393	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	406	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
394		407
395		408
396	=item aio_close $fh, $callback->($status)	409	=item aio_close $fh, $callback->($status)
397		410
398	Asynchronously close a file and call the callback with the result	411	Asynchronously close a file and call the callback with the result
…		…
408	Or in other words: the file descriptor will be closed, but it will not be	421	Or in other words: the file descriptor will be closed, but it will not be
409	free for reuse until the perl filehandle is closed.	422	free for reuse until the perl filehandle is closed.
410		423
411	=cut	424	=cut
412		425
		426	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		427
		428	Seeks the filehandle to the new C<$offset>, similarly to perl's
		429	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		430	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		431	C<IO::AIO::SEEK_END>).
		432
		433	The resulting absolute offset will be passed to the callback, or C<-1> in
		434	case of an error.
		435
		436	In theory, the C<$whence> constants could be different than the
		437	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		438	so don't panic.
		439
		440	As a GNU/Linux (and maybe Solaris) extension, also the constants
		441	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		442	could be found. No guarantees about suitability for use in C<aio_seek> or
		443	Perl's C<sysseek> can be made though, although I would naively assume they
		444	"just work".
		445
413	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	446	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
414		447
415	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	448	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416		449
417	Reads or writes C<$length> bytes from or to the specified C<$fh> and	450	Reads or writes C<$length> bytes from or to the specified C<$fh> and
418	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	451	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
419	and calls the callback without the actual number of bytes read (or -1 on	452	calls the callback with the actual number of bytes transferred (or -1 on
420	error, just like the syscall).	453	error, just like the syscall).
421		454
422	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	455	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
423	offset plus the actual number of bytes read.	456	offset plus the actual number of bytes read.
424		457
…		…
482	As native sendfile syscalls (as practically any non-POSIX interface hacked	515	As native sendfile syscalls (as practically any non-POSIX interface hacked
483	together in a hurry to improve benchmark numbers) tend to be rather buggy	516	together in a hurry to improve benchmark numbers) tend to be rather buggy
484	on many systems, this implementation tries to work around some known bugs	517	on many systems, this implementation tries to work around some known bugs
485	in Linux and FreeBSD kernels (probably others, too), but that might fail,	518	in Linux and FreeBSD kernels (probably others, too), but that might fail,
486	so you really really should check the return value of C<aio_sendfile> -	519	so you really really should check the return value of C<aio_sendfile> -
487	fewre bytes than expected might have been transferred.	520	fewer bytes than expected might have been transferred.
488		521
489		522
490	=item aio_readahead $fh,$offset,$length, $callback->($retval)	523	=item aio_readahead $fh,$offset,$length, $callback->($retval)
491		524
492	C<aio_readahead> populates the page cache with data from a file so that	525	C<aio_readahead> populates the page cache with data from a file so that
…		…
496	whole pages, so that offset is effectively rounded down to a page boundary	529	whole pages, so that offset is effectively rounded down to a page boundary
497	and bytes are read up to the next page boundary greater than or equal to	530	and bytes are read up to the next page boundary greater than or equal to
498	(off-set+length). C<aio_readahead> does not read beyond the end of the	531	(off-set+length). C<aio_readahead> does not read beyond the end of the
499	file. The current file offset of the file is left unchanged.	532	file. The current file offset of the file is left unchanged.
500		533
501	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	534	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
502	emulated by simply reading the data, which would have a similar effect.	535	be emulated by simply reading the data, which would have a similar effect.
503		536
504		537
505	=item aio_stat $fh_or_path, $callback->($status)	538	=item aio_stat $fh_or_path, $callback->($status)
506		539
507	=item aio_lstat $fh, $callback->($status)	540	=item aio_lstat $fh, $callback->($status)
…		…
576	namemax => 255,	609	namemax => 255,
577	frsize => 1024,	610	frsize => 1024,
578	fsid => 1810	611	fsid => 1810
579	}	612	}
580		613
		614	Here is a (likely partial - send me updates!) list of fsid values used by
		615	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		616
		617	0x0000adf5 adfs
		618	0x0000adff affs
		619	0x5346414f afs
		620	0x09041934 anon-inode filesystem
		621	0x00000187 autofs
		622	0x42465331 befs
		623	0x1badface bfs
		624	0x42494e4d binfmt_misc
		625	0x9123683e btrfs
		626	0x0027e0eb cgroupfs
		627	0xff534d42 cifs
		628	0x73757245 coda
		629	0x012ff7b7 coh
		630	0x28cd3d45 cramfs
		631	0x453dcd28 cramfs-wend (wrong endianness)
		632	0x64626720 debugfs
		633	0x00001373 devfs
		634	0x00001cd1 devpts
		635	0x0000f15f ecryptfs
		636	0x00414a53 efs
		637	0x0000137d ext
		638	0x0000ef53 ext2/ext3/ext4
		639	0x0000ef51 ext2
		640	0xf2f52010 f2fs
		641	0x00004006 fat
		642	0x65735546 fuseblk
		643	0x65735543 fusectl
		644	0x0bad1dea futexfs
		645	0x01161970 gfs2
		646	0x47504653 gpfs
		647	0x00004244 hfs
		648	0xf995e849 hpfs
		649	0x00c0ffee hostfs
		650	0x958458f6 hugetlbfs
		651	0x2bad1dea inotifyfs
		652	0x00009660 isofs
		653	0x000072b6 jffs2
		654	0x3153464a jfs
		655	0x6b414653 k-afs
		656	0x0bd00bd0 lustre
		657	0x0000137f minix
		658	0x0000138f minix 30 char names
		659	0x00002468 minix v2
		660	0x00002478 minix v2 30 char names
		661	0x00004d5a minix v3
		662	0x19800202 mqueue
		663	0x00004d44 msdos
		664	0x0000564c novell
		665	0x00006969 nfs
		666	0x6e667364 nfsd
		667	0x00003434 nilfs
		668	0x5346544e ntfs
		669	0x00009fa1 openprom
		670	0x7461636F ocfs2
		671	0x00009fa0 proc
		672	0x6165676c pstorefs
		673	0x0000002f qnx4
		674	0x68191122 qnx6
		675	0x858458f6 ramfs
		676	0x52654973 reiserfs
		677	0x00007275 romfs
		678	0x67596969 rpc_pipefs
		679	0x73636673 securityfs
		680	0xf97cff8c selinux
		681	0x0000517b smb
		682	0x534f434b sockfs
		683	0x73717368 squashfs
		684	0x62656572 sysfs
		685	0x012ff7b6 sysv2
		686	0x012ff7b5 sysv4
		687	0x01021994 tmpfs
		688	0x15013346 udf
		689	0x00011954 ufs
		690	0x54190100 ufs byteswapped
		691	0x00009fa2 usbdevfs
		692	0x01021997 v9fs
		693	0xa501fcf5 vxfs
		694	0xabba1974 xenfs
		695	0x012ff7b4 xenix
		696	0x58465342 xfs
		697	0x012fd16d xia
581		698
582	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	699	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
583		700
584	Works like perl's C<utime> function (including the special case of $atime	701	Works like perl's C<utime> function (including the special case of $atime
585	and $mtime being undef). Fractional times are supported if the underlying	702	and $mtime being undef). Fractional times are supported if the underlying
…		…
613	=item aio_truncate $fh_or_path, $offset, $callback->($status)	730	=item aio_truncate $fh_or_path, $offset, $callback->($status)
614		731
615	Works like truncate(2) or ftruncate(2).	732	Works like truncate(2) or ftruncate(2).
616		733
617		734
		735	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		736
		737	Allocates or frees disk space according to the C<$mode> argument. See the
		738	linux C<fallocate> documentation for details.
		739
		740	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		741	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		742	to deallocate a file range.
		743
		744	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		745	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		746	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		747	to unshare shared blocks (see your L<fallocate(2)> manpage).
		748
		749	The file system block size used by C<fallocate> is presumably the
		750	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		751	can dictate other limitations.
		752
		753	If C<fallocate> isn't available or cannot be emulated (currently no
		754	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		755
		756
618	=item aio_chmod $fh_or_path, $mode, $callback->($status)	757	=item aio_chmod $fh_or_path, $mode, $callback->($status)
619		758
620	Works like perl's C<chmod> function.	759	Works like perl's C<chmod> function.
621		760
622		761
…		…
659		798
660		799
661	=item aio_realpath $pathname, $callback->($path)	800	=item aio_realpath $pathname, $callback->($path)
662		801
663	Asynchronously make the path absolute and resolve any symlinks in	802	Asynchronously make the path absolute and resolve any symlinks in
664	C<$path>. The resulting path only consists of directories (Same as	803	C<$path>. The resulting path only consists of directories (same as
665	L<Cwd::realpath>).	804	L<Cwd::realpath>).
666		805
667	This request can be used to get the absolute path of the current working	806	This request can be used to get the absolute path of the current working
668	directory by passing it a path of F<.> (a single dot).	807	directory by passing it a path of F<.> (a single dot).
669		808
670		809
671	=item aio_rename $srcpath, $dstpath, $callback->($status)	810	=item aio_rename $srcpath, $dstpath, $callback->($status)
672		811
673	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	812	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
674	rename(2) and call the callback with the result code.	813	rename(2) and call the callback with the result code.
		814
		815	On systems that support the AIO::WD working directory abstraction
		816	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		817	of failing, C<rename> is called on the absolute path of C<$wd>.
		818
		819
		820	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		821
		822	Basically a version of C<aio_rename> with an additional C<$flags>
		823	argument. Calling this with C<$flags=0> is the same as calling
		824	C<aio_rename>.
		825
		826	Non-zero flags are currently only supported on GNU/Linux systems that
		827	support renameat2. Other systems fail with C<ENOSYS> in this case.
		828
		829	The following constants are available (missing ones are, as usual C<0>),
		830	see renameat2(2) for details:
		831
		832	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		833	and C<IO::AIO::RENAME_WHITEOUT>.
675		834
676		835
677	=item aio_mkdir $pathname, $mode, $callback->($status)	836	=item aio_mkdir $pathname, $mode, $callback->($status)
678		837
679	Asynchronously mkdir (create) a directory and call the callback with	838	Asynchronously mkdir (create) a directory and call the callback with
…		…
683		842
684	=item aio_rmdir $pathname, $callback->($status)	843	=item aio_rmdir $pathname, $callback->($status)
685		844
686	Asynchronously rmdir (delete) a directory and call the callback with the	845	Asynchronously rmdir (delete) a directory and call the callback with the
687	result code.	846	result code.
		847
		848	On systems that support the AIO::WD working directory abstraction
		849	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		850	C<rmdir> is called on the absolute path of C<$wd>.
688		851
689		852
690	=item aio_readdir $pathname, $callback->($entries)	853	=item aio_readdir $pathname, $callback->($entries)
691		854
692	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	855	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
…		…
1057	}	1220	}
1058		1221
1059	=item aio_rmtree $pathname, $callback->($status)	1222	=item aio_rmtree $pathname, $callback->($status)
1060		1223
1061	Delete a directory tree starting (and including) C<$path>, return the	1224	Delete a directory tree starting (and including) C<$path>, return the
1062	status of the final C<rmdir> only. This is a composite request that	1225	status of the final C<rmdir> only. This is a composite request that
1063	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1226	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1064	everything else.	1227	everything else.
1065		1228
1066	=cut	1229	=cut
1067		1230
…		…
1088	add $grp $dirgrp;	1251	add $grp $dirgrp;
1089	};	1252	};
1090		1253
1091	$grp	1254	$grp
1092	}	1255	}
		1256
		1257	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1258
		1259	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1260
		1261	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1262	they execute asynchronously and pass the return value to the callback.
		1263
		1264	Both calls can be used for a lot of things, some of which make more sense
		1265	to run asynchronously in their own thread, while some others make less
		1266	sense. For example, calls that block waiting for external events, such
		1267	as locking, will also lock down an I/O thread while it is waiting, which
		1268	can deadlock the whole I/O system. At the same time, there might be no
		1269	alternative to using a thread to wait.
		1270
		1271	So in general, you should only use these calls for things that do
		1272	(filesystem) I/O, not for things that wait for other events (network,
		1273	other processes), although if you are careful and know what you are doing,
		1274	you still can.
		1275
		1276	The following constants are available (missing ones are, as usual C<0>):
		1277
		1278	C<F_DUPFD_CLOEXEC>,
		1279
		1280	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1281
		1282	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1283
		1284	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1285	C<FS_IOC_FIEMAP>.
		1286
		1287	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1288	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1289
		1290	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1291	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1292	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1293	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1294	C<FS_FL_USER_MODIFIABLE>.
		1295
		1296	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1297	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1298	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1299	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1093		1300
1094	=item aio_sync $callback->($status)	1301	=item aio_sync $callback->($status)
1095		1302
1096	Asynchronously call sync and call the callback when finished.	1303	Asynchronously call sync and call the callback when finished.
1097		1304
…		…
1166	};	1373	};
1167		1374
1168	$grp	1375	$grp
1169	}	1376	}
1170		1377
1171	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1378	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1172		1379
1173	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1380	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1174	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1381	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1175	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1382	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1176	scalar must only be modified in-place while an aio operation is pending on	1383	scalar must only be modified in-place while an aio operation is pending on
…		…
1178		1385
1179	It calls the C<msync> function of your OS, if available, with the memory	1386	It calls the C<msync> function of your OS, if available, with the memory
1180	area starting at C<$offset> in the string and ending C<$length> bytes	1387	area starting at C<$offset> in the string and ending C<$length> bytes
1181	later. If C<$length> is negative, counts from the end, and if C<$length>	1388	later. If C<$length> is negative, counts from the end, and if C<$length>
1182	is C<undef>, then it goes till the end of the string. The flags can be	1389	is C<undef>, then it goes till the end of the string. The flags can be
1183	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1390	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1184	C<IO::AIO::MS_SYNC>.	1391	C<IO::AIO::MS_INVALIDATE>.
1185		1392
1186	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1393	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1187		1394
1188	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1395	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1189	scalars.	1396	scalars.
1190		1397
1191	It touches (reads or writes) all memory pages in the specified	1398	It touches (reads or writes) all memory pages in the specified
1192	range inside the scalar. All caveats and parameters are the same	1399	range inside the scalar. All caveats and parameters are the same
1193	as for C<aio_msync>, above, except for flags, which must be either	1400	as for C<aio_msync>, above, except for flags, which must be either
1194	C<0> (which reads all pages and ensures they are instantiated) or	1401	C<0> (which reads all pages and ensures they are instantiated) or
1195	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1402	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1196	writing an octet from it, which dirties the page).	1403	writing an octet from it, which dirties the page).
1197		1404
1198	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1405	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1199		1406
1200	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1407	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1231	documented under L<MISCELLANEOUS FUNCTIONS>.	1438	documented under L<MISCELLANEOUS FUNCTIONS>.
1232		1439
1233	Example: asynchronously lock all current and future pages into memory.	1440	Example: asynchronously lock all current and future pages into memory.
1234		1441
1235	aio_mlockall IO::AIO::MCL_FUTURE;	1442	aio_mlockall IO::AIO::MCL_FUTURE;
		1443
		1444	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1445
		1446	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1447	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1448	the ioctl is not available on your OS, then this request will fail with
		1449	C<ENOSYS>.
		1450
		1451	C<$start> is the starting offset to query extents for, C<$length> is the
		1452	size of the range to query - if it is C<undef>, then the whole file will
		1453	be queried.
		1454
		1455	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1456	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1457	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1458	the data portion.
		1459
		1460	C<$count> is the maximum number of extent records to return. If it is
		1461	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1462	case, if it is C<0>, then the callback receives the number of extents
		1463	instead of the extents themselves (which is unreliable, see below).
		1464
		1465	If an error occurs, the callback receives no arguments. The special
		1466	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1467
		1468	Otherwise, the callback receives an array reference with extent
		1469	structures. Each extent structure is an array reference itself, with the
		1470	following members:
		1471
		1472	[$logical, $physical, $length, $flags]
		1473
		1474	Flags is any combination of the following flag values (typically either C<0>
		1475	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1476
		1477	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1478	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1479	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1480	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1481	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1482	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1483
		1484	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1485	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1486	it to return all extents of a range for files with large number of
		1487	extents. The code works around all these issues if C<$count> is undef.
1236		1488
1237	=item aio_group $callback->(...)	1489	=item aio_group $callback->(...)
1238		1490
1239	This is a very special aio request: Instead of doing something, it is a	1491	This is a very special aio request: Instead of doing something, it is a
1240	container for other aio requests, which is useful if you want to bundle	1492	container for other aio requests, which is useful if you want to bundle
…		…
1304	object. This object stores the canonicalised, absolute version of the	1556	object. This object stores the canonicalised, absolute version of the
1305	path, and on systems that allow it, also a directory file descriptor.	1557	path, and on systems that allow it, also a directory file descriptor.
1306		1558
1307	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>	1559	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1308	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD	1560	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1309	object and a pathname instead. If the pathname is absolute, the	1561	object and a pathname instead (or the IO::AIO::WD object alone, which
		1562	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1310	IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative	1563	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1311	to that IO::AIO::WD object.	1564	to that IO::AIO::WD object.
1312		1565
1313	For example, to get a wd object for F</etc> and then stat F<passwd>	1566	For example, to get a wd object for F</etc> and then stat F<passwd>
1314	inside, you would write:	1567	inside, you would write:
1315		1568
…		…
1323	aio_stat [$etcdir, "passwd"], sub {	1576	aio_stat [$etcdir, "passwd"], sub {
1324	# yay	1577	# yay
1325	};	1578	};
1326	};	1579	};
1327		1580
		1581	The fact that C<aio_wd> is a request and not a normal function shows that
1328	This shows that creating an IO::AIO::WD object is itself a potentially	1582	creating an IO::AIO::WD object is itself a potentially blocking operation,
1329	blocking operation, which is why it is done asynchronously.	1583	which is why it is done asynchronously.
		1584
		1585	To stat the directory obtained with C<aio_wd> above, one could write
		1586	either of the following three request calls:
		1587
		1588	aio_lstat "/etc" , sub { ... # pathname as normal string
		1589	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1590	aio_lstat $wd , sub { ... # shorthand for the previous
1330		1591
1331	As with normal pathnames, IO::AIO keeps a copy of the working directory	1592	As with normal pathnames, IO::AIO keeps a copy of the working directory
1332	object and the pathname string, so you could write the following without	1593	object and the pathname string, so you could write the following without
1333	causing any issues due to C<$path> getting reused:	1594	causing any issues due to C<$path> getting reused:
1334		1595
…		…
1347	will still point to the original directory. Most functions accepting a	1608	will still point to the original directory. Most functions accepting a
1348	pathname will use the directory fd on newer systems, and the string on	1609	pathname will use the directory fd on newer systems, and the string on
1349	older systems. Some functions (such as realpath) will always rely on the	1610	older systems. Some functions (such as realpath) will always rely on the
1350	string form of the pathname.	1611	string form of the pathname.
1351		1612
1352	So this fucntionality is mainly useful to get some protection against	1613	So this functionality is mainly useful to get some protection against
1353	C<chdir>, to easily get an absolute path out of a relative path for future	1614	C<chdir>, to easily get an absolute path out of a relative path for future
1354	reference, and to speed up doing many operations in the same directory	1615	reference, and to speed up doing many operations in the same directory
1355	(e.g. when stat'ing all files in a directory).	1616	(e.g. when stat'ing all files in a directory).
1356		1617
1357	The following functions implement this working directory abstraction:	1618	The following functions implement this working directory abstraction:
…		…
1370	passing C<undef> as working directory component of a pathname fails the	1631	passing C<undef> as working directory component of a pathname fails the
1371	request with C<ENOENT>, there is often no need for error checking in the	1632	request with C<ENOENT>, there is often no need for error checking in the
1372	C<aio_wd> callback, as future requests using the value will fail in the	1633	C<aio_wd> callback, as future requests using the value will fail in the
1373	expected way.	1634	expected way.
1374		1635
1375	If this call isn't available because your OS lacks it or it couldn't be
1376	detected, it will be emulated by calling C<fsync> instead.
1377
1378	=item IO::AIO::CWD	1636	=item IO::AIO::CWD
1379		1637
1380	This is a compiletime constant (object) that represents the process	1638	This is a compiletime constant (object) that represents the process
1381	current working directory.	1639	current working directory.
1382		1640
1383	Specifying this object as working directory object for a pathname is as	1641	Specifying this object as working directory object for a pathname is as if
1384	if the pathname would be specified directly, without a directory object,	1642	the pathname would be specified directly, without a directory object. For
1385	e.g., these calls are functionally identical:	1643	example, these calls are functionally identical:
1386		1644
1387	aio_stat "somefile", sub { ... };	1645	aio_stat "somefile", sub { ... };
1388	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1646	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1389		1647
1390	=back	1648	=back
1391		1649
		1650	To recover the path associated with an IO::AIO::WD object, you can use
		1651	C<aio_realpath>:
		1652
		1653	aio_realpath $wd, sub {
		1654	warn "path is $_[0]\n";
		1655	};
		1656
		1657	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1658	sometimes, fall back to using an absolue path.
1392		1659
1393	=head2 IO::AIO::REQ CLASS	1660	=head2 IO::AIO::REQ CLASS
1394		1661
1395	All non-aggregate C<aio_*> functions return an object of this class when	1662	All non-aggregate C<aio_*> functions return an object of this class when
1396	called in non-void context.	1663	called in non-void context.
…		…
1574		1841
1575	See C<poll_cb> for an example.	1842	See C<poll_cb> for an example.
1576		1843
1577	=item IO::AIO::poll_cb	1844	=item IO::AIO::poll_cb
1578		1845
1579	Process some outstanding events on the result pipe. You have to call	1846	Process some requests that have reached the result phase (i.e. they have
		1847	been executed but the results are not yet reported). You have to call
		1848	this "regularly" to finish outstanding requests.
		1849
1580	this regularly. Returns C<0> if all events could be processed (or there	1850	Returns C<0> if all events could be processed (or there were no
1581	were no events to process), or C<-1> if it returned earlier for whatever	1851	events to process), or C<-1> if it returned earlier for whatever
1582	reason. Returns immediately when no events are outstanding. The amount of	1852	reason. Returns immediately when no events are outstanding. The amount
1583	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1853	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1584	C<IO::AIO::max_poll_time>.	1854	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1585		1855
1586	If not all requests were processed for whatever reason, the filehandle	1856	If not all requests were processed for whatever reason, the poll file
1587	will still be ready when C<poll_cb> returns, so normally you don't have to	1857	descriptor will still be ready when C<poll_cb> returns, so normally you
1588	do anything special to have it called later.	1858	don't have to do anything special to have it called later.
1589		1859
1590	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1860	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1591	ready, it can be beneficial to call this function from loops which submit	1861	ready, it can be beneficial to call this function from loops which submit
1592	a lot of requests, to make sure the results get processed when they become	1862	a lot of requests, to make sure the results get processed when they become
1593	available and not just when the loop is finished and the event loop takes	1863	available and not just when the loop is finished and the event loop takes
…		…
1602	poll => 'r', async => 1,	1872	poll => 'r', async => 1,
1603	cb => \&IO::AIO::poll_cb);	1873	cb => \&IO::AIO::poll_cb);
1604		1874
1605	=item IO::AIO::poll_wait	1875	=item IO::AIO::poll_wait
1606		1876
1607	If there are any outstanding requests and none of them in the result	1877	Wait until either at least one request is in the result phase or no
1608	phase, wait till the result filehandle becomes ready for reading (simply	1878	requests are outstanding anymore.
1609	does a C<select> on the filehandle. This is useful if you want to	1879
1610	synchronously wait for some requests to finish).	1880	This is useful if you want to synchronously wait for some requests to
		1881	become ready, without actually handling them.
1611		1882
1612	See C<nreqs> for an example.	1883	See C<nreqs> for an example.
1613		1884
1614	=item IO::AIO::poll	1885	=item IO::AIO::poll
1615		1886
…		…
1736		2007
1737	This is a very bad function to use in interactive programs because it	2008	This is a very bad function to use in interactive programs because it
1738	blocks, and a bad way to reduce concurrency because it is inexact: Better	2009	blocks, and a bad way to reduce concurrency because it is inexact: Better
1739	use an C<aio_group> together with a feed callback.	2010	use an C<aio_group> together with a feed callback.
1740		2011
1741	It's main use is in scripts without an event loop - when you want to stat	2012	Its main use is in scripts without an event loop - when you want to stat
1742	a lot of files, you can write somehting like this:	2013	a lot of files, you can write something like this:
1743		2014
1744	IO::AIO::max_outstanding 32;	2015	IO::AIO::max_outstanding 32;
1745		2016
1746	for my $path (...) {	2017	for my $path (...) {
1747	aio_stat $path , ...;	2018	aio_stat $path , ...;
…		…
1786		2057
1787	=back	2058	=back
1788		2059
1789	=head3 MISCELLANEOUS FUNCTIONS	2060	=head3 MISCELLANEOUS FUNCTIONS
1790		2061
1791	IO::AIO implements some functions that might be useful, but are not	2062	IO::AIO implements some functions that are useful when you want to use
1792	asynchronous.	2063	some "Advanced I/O" function not available to in Perl, without going the
		2064	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2065	counterpart.
1793		2066
1794	=over 4	2067	=over 4
1795		2068
1796	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2069	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1797		2070
…		…
1816	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2089	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1817		2090
1818	Simply calls the C<posix_madvise> function (see its	2091	Simply calls the C<posix_madvise> function (see its
1819	manpage for details). The following advice constants are	2092	manpage for details). The following advice constants are
1820	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2093	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1821	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2094	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2095	C<IO::AIO::MADV_DONTNEED>.
		2096
		2097	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2098	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2099	will be reduced to fit into the C<$scalar>.
1822		2100
1823	On systems that do not implement C<posix_madvise>, this function returns	2101	On systems that do not implement C<posix_madvise>, this function returns
1824	ENOSYS, otherwise the return value of C<posix_madvise>.	2102	ENOSYS, otherwise the return value of C<posix_madvise>.
1825		2103
1826	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2104	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1828	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2106	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1829	$scalar (see its manpage for details). The following protect	2107	$scalar (see its manpage for details). The following protect
1830	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2108	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1831	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2109	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1832		2110
		2111	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2112	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2113	will be reduced to fit into the C<$scalar>.
		2114
1833	On systems that do not implement C<mprotect>, this function returns	2115	On systems that do not implement C<mprotect>, this function returns
1834	ENOSYS, otherwise the return value of C<mprotect>.	2116	ENOSYS, otherwise the return value of C<mprotect>.
1835		2117
1836	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2118	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1837		2119
1838	Memory-maps a file (or anonymous memory range) and attaches it to the	2120	Memory-maps a file (or anonymous memory range) and attaches it to the
1839	given C<$scalar>, which will act like a string scalar.	2121	given C<$scalar>, which will act like a string scalar. Returns true on
		2122	success, and false otherwise.
1840		2123
		2124	The scalar must exist, but its contents do not matter - this means you
		2125	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2126	the scalar first.
		2127
1841	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2128	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1842	change the string length, and most read-only operations such as copying it	2129	which don't change the string length, and most read-only operations such
1843	or searching it with regexes and so on.	2130	as copying it or searching it with regexes and so on.
1844		2131
1845	Anything else is unsafe and will, at best, result in memory leaks.	2132	Anything else is unsafe and will, at best, result in memory leaks.
1846		2133
1847	The memory map associated with the C<$scalar> is automatically removed	2134	The memory map associated with the C<$scalar> is automatically removed
1848	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2135	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1849	C<IO::AIO::munmap> functions are called.	2136	or C<IO::AIO::munmap> functions are called on it.
1850		2137
1851	This calls the C<mmap>(2) function internally. See your system's manual	2138	This calls the C<mmap>(2) function internally. See your system's manual
1852	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2139	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1853		2140
1854	The C<$length> must be larger than zero and smaller than the actual	2141	The C<$length> must be larger than zero and smaller than the actual
1855	filesize.	2142	filesize.
1856		2143
1857	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2144	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1858	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2145	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1859		2146
1860	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2147	C<$flags> can be a combination of
1861	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2148	C<IO::AIO::MAP_SHARED> or
1862	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2149	C<IO::AIO::MAP_PRIVATE>,
		2150	or a number of system-specific flags (when not available, the are C<0>):
1863	(which is set to C<MAP_ANON> if your system only provides this	2151	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1864	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2152	C<IO::AIO::MAP_LOCKED>,
1865	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2153	C<IO::AIO::MAP_NORESERVE>,
		2154	C<IO::AIO::MAP_POPULATE>,
1866	C<IO::AIO::MAP_NONBLOCK>	2155	C<IO::AIO::MAP_NONBLOCK>,
		2156	C<IO::AIO::MAP_FIXED>,
		2157	C<IO::AIO::MAP_GROWSDOWN>,
		2158	C<IO::AIO::MAP_32BIT>,
		2159	C<IO::AIO::MAP_HUGETLB> or
		2160	C<IO::AIO::MAP_STACK>.
1867		2161
1868	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2162	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1869		2163
1870	C<$offset> is the offset from the start of the file - it generally must be	2164	C<$offset> is the offset from the start of the file - it generally must be
1871	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2165	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1896		2190
1897	Calls the C<munlockall> function.	2191	Calls the C<munlockall> function.
1898		2192
1899	On systems that do not implement C<munlockall>, this function returns	2193	On systems that do not implement C<munlockall>, this function returns
1900	ENOSYS, otherwise the return value of C<munlockall>.	2194	ENOSYS, otherwise the return value of C<munlockall>.
		2195
		2196	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2197
		2198	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2199	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2200	should be the file offset.
		2201
		2202	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2203	silently corrupt the data in this case.
		2204
		2205	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2206	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2207	C<IO::AIO::SPLICE_F_GIFT>.
		2208
		2209	See the C<splice(2)> manpage for details.
		2210
		2211	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2212
		2213	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2214	description for C<IO::AIO::splice> above for details.
		2215
		2216	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2217
		2218	Attempts to query or change the pipe buffer size. Obviously works only
		2219	on pipes, and currently works only on GNU/Linux systems, and fails with
		2220	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2221	size on other systems, drop me a note.
		2222
		2223	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2224
		2225	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2226	C<$flags> is missing or C<0>, then this should be the same as a call to
		2227	perl's built-in C<pipe> function and create a new pipe, and works on
		2228	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2229	(..., 4096, O_BINARY)>.
		2230
		2231	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2232	the given flags (Linux 2.6.27, glibc 2.9).
		2233
		2234	On success, the read and write file handles are returned.
		2235
		2236	On error, nothing will be returned. If the pipe2 syscall is missing and
		2237	C<$flags> is non-zero, fails with C<ENOSYS>.
		2238
		2239	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2240	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2241	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1901		2242
1902	=back	2243	=back
1903		2244
1904	=cut	2245	=cut
1905		2246

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC vs. Revision 1.274 by root, Thu Sep 21 23:43:46 2017 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC vs.
Revision 1.274 by root, Thu Sep 21 23:43:46 2017 UTC