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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.217 by root, Sun Oct 9 22:25:00 2011 UTC vs.
Revision 1.268 by root, Tue May 30 22:45:52 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 = '4.11';	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_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
…		…
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)
232	aio_mkdir $pathname, $mode, $callback->($status)	238	aio_mkdir $pathname, $mode, $callback->($status)
233	aio_rmdir $pathname, $callback->($status)	239	aio_rmdir $pathname, $callback->($status)
234	aio_readdir $pathname, $callback->($entries)	240	aio_readdir $pathname, $callback->($entries)
235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	241	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
…		…
238	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	244	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
239	aio_load $pathname, $data, $callback->($status)	245	aio_load $pathname, $data, $callback->($status)
240	aio_copy $srcpath, $dstpath, $callback->($status)	246	aio_copy $srcpath, $dstpath, $callback->($status)
241	aio_move $srcpath, $dstpath, $callback->($status)	247	aio_move $srcpath, $dstpath, $callback->($status)
242	aio_rmtree $pathname, $callback->($status)	248	aio_rmtree $pathname, $callback->($status)
		249	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		250	aio_ioctl $fh, $request, $buf, $callback->($status)
243	aio_sync $callback->($status)	251	aio_sync $callback->($status)
244	aio_syncfs $fh, $callback->($status)	252	aio_syncfs $fh, $callback->($status)
245	aio_fsync $fh, $callback->($status)	253	aio_fsync $fh, $callback->($status)
246	aio_fdatasync $fh, $callback->($status)	254	aio_fdatasync $fh, $callback->($status)
247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	255	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248	aio_pathsync $pathname, $callback->($status)	256	aio_pathsync $pathname, $callback->($status)
249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	257	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	258	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	259	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252	aio_mlockall $flags, $callback->($status)	260	aio_mlockall $flags, $callback->($status)
253	aio_group $callback->(...)	261	aio_group $callback->(...)
254	aio_nop $callback->()	262	aio_nop $callback->()
…		…
271	IO::AIO::nready	279	IO::AIO::nready
272	IO::AIO::npending	280	IO::AIO::npending
273		281
274	IO::AIO::sendfile $ofh, $ifh, $offset, $count	282	IO::AIO::sendfile $ofh, $ifh, $offset, $count
275	IO::AIO::fadvise $fh, $offset, $len, $advice	283	IO::AIO::fadvise $fh, $offset, $len, $advice
		284	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		285	IO::AIO::munmap $scalar
276	IO::AIO::madvise $scalar, $offset, $length, $advice	286	IO::AIO::madvise $scalar, $offset, $length, $advice
277	IO::AIO::mprotect $scalar, $offset, $length, $protect	287	IO::AIO::mprotect $scalar, $offset, $length, $protect
278	IO::AIO::munlock $scalar, $offset = 0, $length = undef	288	IO::AIO::munlock $scalar, $offset = 0, $length = undef
279	IO::AIO::munlockall	289	IO::AIO::munlockall
280		290
281	=head2 AIO REQUEST FUNCTIONS	291	=head2 API NOTES
282		292
283	All the C<aio_*> calls are more or less thin wrappers around the syscall	293	All the C<aio_*> calls are more or less thin wrappers around the syscall
284	with the same name (sans C<aio_>). The arguments are similar or identical,	294	with the same name (sans C<aio_>). The arguments are similar or identical,
285	and they all accept an additional (and optional) C<$callback> argument	295	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	296	which must be a code reference. This code reference will be called after
…		…
317	correct contents.	327	correct contents.
318		328
319	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	329	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
320	handles correctly whether it is set or not.	330	handles correctly whether it is set or not.
321		331
		332	=head2 AIO REQUEST FUNCTIONS
		333
322	=over 4	334	=over 4
323		335
324	=item $prev_pri = aioreq_pri [$pri]	336	=item $prev_pri = aioreq_pri [$pri]
325		337
326	Returns the priority value that would be used for the next request and, if	338	Returns the priority value that would be used for the next request and, if
…		…
355		367
356		368
357	=item aio_open $pathname, $flags, $mode, $callback->($fh)	369	=item aio_open $pathname, $flags, $mode, $callback->($fh)
358		370
359	Asynchronously open or create a file and call the callback with a newly	371	Asynchronously open or create a file and call the callback with a newly
360	created filehandle for the file.	372	created filehandle for the file (or C<undef> in case of an error).
361		373
362	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	374	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
363	for an explanation.	375	for an explanation.
364		376
365	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	377	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
388	following POSIX and non-POSIX constants are available (missing ones on	400	following POSIX and non-POSIX constants are available (missing ones on
389	your system are, as usual, C<0>):	401	your system are, as usual, C<0>):
390		402
391	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	403	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>,	404	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>.	405	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
394		406
395		407
396	=item aio_close $fh, $callback->($status)	408	=item aio_close $fh, $callback->($status)
397		409
398	Asynchronously close a file and call the callback with the result	410	Asynchronously close a file and call the callback with the result
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408	Or in other words: the file descriptor will be closed, but it will not be	420	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.	421	free for reuse until the perl filehandle is closed.
410		422
411	=cut	423	=cut
412		424
		425	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		426
		427	Seeks the filehandle to the new C<$offset>, similarly to perl's
		428	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		429	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		430	C<IO::AIO::SEEK_END>).
		431
		432	The resulting absolute offset will be passed to the callback, or C<-1> in
		433	case of an error.
		434
		435	In theory, the C<$whence> constants could be different than the
		436	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		437	so don't panic.
		438
		439	As a GNU/Linux (and maybe Solaris) extension, also the constants
		440	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		441	could be found. No guarantees about suitability for use in C<aio_seek> or
		442	Perl's C<sysseek> can be made though, although I would naively assume they
		443	"just work".
		444
413	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	445	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
414		446
415	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	447	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416		448
417	Reads or writes C<$length> bytes from or to the specified C<$fh> and	449	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<$dataoffset>	450	C<$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	451	calls the callback with the actual number of bytes transferred (or -1 on
420	error, just like the syscall).	452	error, just like the syscall).
421		453
422	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	454	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
423	offset plus the actual number of bytes read.	455	offset plus the actual number of bytes read.
424		456
…		…
482	As native sendfile syscalls (as practically any non-POSIX interface hacked	514	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	515	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	516	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,	517	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> -	518	so you really really should check the return value of C<aio_sendfile> -
487	fewre bytes than expected might have been transferred.	519	fewer bytes than expected might have been transferred.
488		520
489		521
490	=item aio_readahead $fh,$offset,$length, $callback->($retval)	522	=item aio_readahead $fh,$offset,$length, $callback->($retval)
491		523
492	C<aio_readahead> populates the page cache with data from a file so that	524	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	528	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	529	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	530	(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.	531	file. The current file offset of the file is left unchanged.
500		532
501	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	533	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.	534	be emulated by simply reading the data, which would have a similar effect.
503		535
504		536
505	=item aio_stat $fh_or_path, $callback->($status)	537	=item aio_stat $fh_or_path, $callback->($status)
506		538
507	=item aio_lstat $fh, $callback->($status)	539	=item aio_lstat $fh, $callback->($status)
…		…
576	namemax => 255,	608	namemax => 255,
577	frsize => 1024,	609	frsize => 1024,
578	fsid => 1810	610	fsid => 1810
579	}	611	}
580		612
		613	Here is a (likely partial - send me updates!) list of fsid values used by
		614	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		615
		616	0x0000adf5 adfs
		617	0x0000adff affs
		618	0x5346414f afs
		619	0x09041934 anon-inode filesystem
		620	0x00000187 autofs
		621	0x42465331 befs
		622	0x1badface bfs
		623	0x42494e4d binfmt_misc
		624	0x9123683e btrfs
		625	0x0027e0eb cgroupfs
		626	0xff534d42 cifs
		627	0x73757245 coda
		628	0x012ff7b7 coh
		629	0x28cd3d45 cramfs
		630	0x453dcd28 cramfs-wend (wrong endianness)
		631	0x64626720 debugfs
		632	0x00001373 devfs
		633	0x00001cd1 devpts
		634	0x0000f15f ecryptfs
		635	0x00414a53 efs
		636	0x0000137d ext
		637	0x0000ef53 ext2/ext3/ext4
		638	0x0000ef51 ext2
		639	0xf2f52010 f2fs
		640	0x00004006 fat
		641	0x65735546 fuseblk
		642	0x65735543 fusectl
		643	0x0bad1dea futexfs
		644	0x01161970 gfs2
		645	0x47504653 gpfs
		646	0x00004244 hfs
		647	0xf995e849 hpfs
		648	0x00c0ffee hostfs
		649	0x958458f6 hugetlbfs
		650	0x2bad1dea inotifyfs
		651	0x00009660 isofs
		652	0x000072b6 jffs2
		653	0x3153464a jfs
		654	0x6b414653 k-afs
		655	0x0bd00bd0 lustre
		656	0x0000137f minix
		657	0x0000138f minix 30 char names
		658	0x00002468 minix v2
		659	0x00002478 minix v2 30 char names
		660	0x00004d5a minix v3
		661	0x19800202 mqueue
		662	0x00004d44 msdos
		663	0x0000564c novell
		664	0x00006969 nfs
		665	0x6e667364 nfsd
		666	0x00003434 nilfs
		667	0x5346544e ntfs
		668	0x00009fa1 openprom
		669	0x7461636F ocfs2
		670	0x00009fa0 proc
		671	0x6165676c pstorefs
		672	0x0000002f qnx4
		673	0x68191122 qnx6
		674	0x858458f6 ramfs
		675	0x52654973 reiserfs
		676	0x00007275 romfs
		677	0x67596969 rpc_pipefs
		678	0x73636673 securityfs
		679	0xf97cff8c selinux
		680	0x0000517b smb
		681	0x534f434b sockfs
		682	0x73717368 squashfs
		683	0x62656572 sysfs
		684	0x012ff7b6 sysv2
		685	0x012ff7b5 sysv4
		686	0x01021994 tmpfs
		687	0x15013346 udf
		688	0x00011954 ufs
		689	0x54190100 ufs byteswapped
		690	0x00009fa2 usbdevfs
		691	0x01021997 v9fs
		692	0xa501fcf5 vxfs
		693	0xabba1974 xenfs
		694	0x012ff7b4 xenix
		695	0x58465342 xfs
		696	0x012fd16d xia
581		697
582	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	698	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
583		699
584	Works like perl's C<utime> function (including the special case of $atime	700	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	701	and $mtime being undef). Fractional times are supported if the underlying
…		…
613	=item aio_truncate $fh_or_path, $offset, $callback->($status)	729	=item aio_truncate $fh_or_path, $offset, $callback->($status)
614		730
615	Works like truncate(2) or ftruncate(2).	731	Works like truncate(2) or ftruncate(2).
616		732
617		733
		734	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		735
		736	Allocates or frees disk space according to the C<$mode> argument. See the
		737	linux C<fallocate> documentation for details.
		738
		739	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		740	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		741	to deallocate a file range.
		742
		743	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		744	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		745	your L<fallocate(2)> manpage).
		746
		747	The file system block size used by C<fallocate> is presumably the
		748	C<f_bsize> returned by C<statvfs>.
		749
		750	If C<fallocate> isn't available or cannot be emulated (currently no
		751	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		752
		753
618	=item aio_chmod $fh_or_path, $mode, $callback->($status)	754	=item aio_chmod $fh_or_path, $mode, $callback->($status)
619		755
620	Works like perl's C<chmod> function.	756	Works like perl's C<chmod> function.
621		757
622		758
…		…
659		795
660		796
661	=item aio_realpath $pathname, $callback->($path)	797	=item aio_realpath $pathname, $callback->($path)
662		798
663	Asynchronously make the path absolute and resolve any symlinks in	799	Asynchronously make the path absolute and resolve any symlinks in
664	C<$path>. The resulting path only consists of directories (Same as	800	C<$path>. The resulting path only consists of directories (same as
665	L<Cwd::realpath>).	801	L<Cwd::realpath>).
666		802
667	This request can be used to get the absolute path of the current working	803	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).	804	directory by passing it a path of F<.> (a single dot).
669		805
670		806
671	=item aio_rename $srcpath, $dstpath, $callback->($status)	807	=item aio_rename $srcpath, $dstpath, $callback->($status)
672		808
673	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	809	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
674	rename(2) and call the callback with the result code.	810	rename(2) and call the callback with the result code.
		811
		812	On systems that support the AIO::WD working directory abstraction
		813	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		814	of failing, C<rename> is called on the absolute path of C<$wd>.
675		815
676		816
677	=item aio_mkdir $pathname, $mode, $callback->($status)	817	=item aio_mkdir $pathname, $mode, $callback->($status)
678		818
679	Asynchronously mkdir (create) a directory and call the callback with	819	Asynchronously mkdir (create) a directory and call the callback with
…		…
683		823
684	=item aio_rmdir $pathname, $callback->($status)	824	=item aio_rmdir $pathname, $callback->($status)
685		825
686	Asynchronously rmdir (delete) a directory and call the callback with the	826	Asynchronously rmdir (delete) a directory and call the callback with the
687	result code.	827	result code.
		828
		829	On systems that support the AIO::WD working directory abstraction
		830	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		831	C<rmdir> is called on the absolute path of C<$wd>.
688		832
689		833
690	=item aio_readdir $pathname, $callback->($entries)	834	=item aio_readdir $pathname, $callback->($entries)
691		835
692	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	836	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
…		…
1057	}	1201	}
1058		1202
1059	=item aio_rmtree $pathname, $callback->($status)	1203	=item aio_rmtree $pathname, $callback->($status)
1060		1204
1061	Delete a directory tree starting (and including) C<$path>, return the	1205	Delete a directory tree starting (and including) C<$path>, return the
1062	status of the final C<rmdir> only. This is a composite request that	1206	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	1207	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1064	everything else.	1208	everything else.
1065		1209
1066	=cut	1210	=cut
1067		1211
…		…
1088	add $grp $dirgrp;	1232	add $grp $dirgrp;
1089	};	1233	};
1090		1234
1091	$grp	1235	$grp
1092	}	1236	}
		1237
		1238	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1239
		1240	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1241
		1242	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1243	they execute asynchronously and pass the return value to the callback.
		1244
		1245	Both calls can be used for a lot of things, some of which make more sense
		1246	to run asynchronously in their own thread, while some others make less
		1247	sense. For example, calls that block waiting for external events, such
		1248	as locking, will also lock down an I/O thread while it is waiting, which
		1249	can deadlock the whole I/O system. At the same time, there might be no
		1250	alternative to using a thread to wait.
		1251
		1252	So in general, you should only use these calls for things that do
		1253	(filesystem) I/O, not for things that wait for other events (network,
		1254	other processes), although if you are careful and know what you are doing,
		1255	you still can.
		1256
		1257	The following constants are available (missing ones are, as usual C<0>):
		1258
		1259	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1260
		1261	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1262	C<FS_IOC_FIEMAP>.
		1263
		1264	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1265	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1266
		1267	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1268	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1269	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1270	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1271	C<FS_FL_USER_MODIFIABLE>.
		1272
		1273	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1274	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1275	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1276	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1093		1277
1094	=item aio_sync $callback->($status)	1278	=item aio_sync $callback->($status)
1095		1279
1096	Asynchronously call sync and call the callback when finished.	1280	Asynchronously call sync and call the callback when finished.
1097		1281
…		…
1166	};	1350	};
1167		1351
1168	$grp	1352	$grp
1169	}	1353	}
1170		1354
1171	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1355	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1172		1356
1173	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1357	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	1358	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	1359	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	1360	scalar must only be modified in-place while an aio operation is pending on
…		…
1178		1362
1179	It calls the C<msync> function of your OS, if available, with the memory	1363	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	1364	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>	1365	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	1366	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	1367	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1184	C<IO::AIO::MS_SYNC>.	1368	C<IO::AIO::MS_INVALIDATE>.
1185		1369
1186	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1370	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1187		1371
1188	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1372	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1189	scalars.	1373	scalars.
1190		1374
1191	It touches (reads or writes) all memory pages in the specified	1375	It touches (reads or writes) all memory pages in the specified
1192	range inside the scalar. All caveats and parameters are the same	1376	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	1377	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	1378	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	1379	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1196	writing an octet from it, which dirties the page).	1380	writing an octet from it, which dirties the page).
1197		1381
1198	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1382	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1199		1383
1200	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1384	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1231	documented under L<MISCELLANEOUS FUNCTIONS>.	1415	documented under L<MISCELLANEOUS FUNCTIONS>.
1232		1416
1233	Example: asynchronously lock all current and future pages into memory.	1417	Example: asynchronously lock all current and future pages into memory.
1234		1418
1235	aio_mlockall IO::AIO::MCL_FUTURE;	1419	aio_mlockall IO::AIO::MCL_FUTURE;
		1420
		1421	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1422
		1423	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1424	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1425	the ioctl is not available on your OS, then this request will fail with
		1426	C<ENOSYS>.
		1427
		1428	C<$start> is the starting offset to query extents for, C<$length> is the
		1429	size of the range to query - if it is C<undef>, then the whole file will
		1430	be queried.
		1431
		1432	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1433	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1434	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1435	the data portion.
		1436
		1437	C<$count> is the maximum number of extent records to return. If it is
		1438	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1439	case, if it is C<0>, then the callback receives the number of extents
		1440	instead of the extents themselves (which is unreliable, see below).
		1441
		1442	If an error occurs, the callback receives no arguments. The special
		1443	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1444
		1445	Otherwise, the callback receives an array reference with extent
		1446	structures. Each extent structure is an array reference itself, with the
		1447	following members:
		1448
		1449	[$logical, $physical, $length, $flags]
		1450
		1451	Flags is any combination of the following flag values (typically either C<0>
		1452	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1453
		1454	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1455	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1456	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1457	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1458	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1459	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1460
		1461	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1462	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1463	it to return all extents of a range for files with large number of
		1464	extents. The code works around all these issues if C<$count> is undef.
1236		1465
1237	=item aio_group $callback->(...)	1466	=item aio_group $callback->(...)
1238		1467
1239	This is a very special aio request: Instead of doing something, it is a	1468	This is a very special aio request: Instead of doing something, it is a
1240	container for other aio requests, which is useful if you want to bundle	1469	container for other aio requests, which is useful if you want to bundle
…		…
1324	aio_stat [$etcdir, "passwd"], sub {	1553	aio_stat [$etcdir, "passwd"], sub {
1325	# yay	1554	# yay
1326	};	1555	};
1327	};	1556	};
1328		1557
1329	That C<aio_wd> is a request and not a normal function shows that creating	1558	The fact that C<aio_wd> is a request and not a normal function shows that
1330	an IO::AIO::WD object is itself a potentially blocking operation, which is	1559	creating an IO::AIO::WD object is itself a potentially blocking operation,
1331	why it is done asynchronously.	1560	which is why it is done asynchronously.
1332		1561
1333	To stat the directory obtained with C<aio_wd> above, one could write	1562	To stat the directory obtained with C<aio_wd> above, one could write
1334	either of the following three request calls:	1563	either of the following three request calls:
1335		1564
1336	aio_lstat "/etc" , sub { ... # pathname as normal string	1565	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1356	will still point to the original directory. Most functions accepting a	1585	will still point to the original directory. Most functions accepting a
1357	pathname will use the directory fd on newer systems, and the string on	1586	pathname will use the directory fd on newer systems, and the string on
1358	older systems. Some functions (such as realpath) will always rely on the	1587	older systems. Some functions (such as realpath) will always rely on the
1359	string form of the pathname.	1588	string form of the pathname.
1360		1589
1361	So this fucntionality is mainly useful to get some protection against	1590	So this functionality is mainly useful to get some protection against
1362	C<chdir>, to easily get an absolute path out of a relative path for future	1591	C<chdir>, to easily get an absolute path out of a relative path for future
1363	reference, and to speed up doing many operations in the same directory	1592	reference, and to speed up doing many operations in the same directory
1364	(e.g. when stat'ing all files in a directory).	1593	(e.g. when stat'ing all files in a directory).
1365		1594
1366	The following functions implement this working directory abstraction:	1595	The following functions implement this working directory abstraction:
…		…
1379	passing C<undef> as working directory component of a pathname fails the	1608	passing C<undef> as working directory component of a pathname fails the
1380	request with C<ENOENT>, there is often no need for error checking in the	1609	request with C<ENOENT>, there is often no need for error checking in the
1381	C<aio_wd> callback, as future requests using the value will fail in the	1610	C<aio_wd> callback, as future requests using the value will fail in the
1382	expected way.	1611	expected way.
1383		1612
1384	If this call isn't available because your OS lacks it or it couldn't be
1385	detected, it will be emulated by calling C<fsync> instead.
1386
1387	=item IO::AIO::CWD	1613	=item IO::AIO::CWD
1388		1614
1389	This is a compiletime constant (object) that represents the process	1615	This is a compiletime constant (object) that represents the process
1390	current working directory.	1616	current working directory.
1391		1617
1392	Specifying this object as working directory object for a pathname is as	1618	Specifying this object as working directory object for a pathname is as if
1393	if the pathname would be specified directly, without a directory object,	1619	the pathname would be specified directly, without a directory object. For
1394	e.g., these calls are functionally identical:	1620	example, these calls are functionally identical:
1395		1621
1396	aio_stat "somefile", sub { ... };	1622	aio_stat "somefile", sub { ... };
1397	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1623	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1398		1624
1399	=back	1625	=back
1400		1626
		1627	To recover the path associated with an IO::AIO::WD object, you can use
		1628	C<aio_realpath>:
		1629
		1630	aio_realpath $wd, sub {
		1631	warn "path is $_[0]\n";
		1632	};
		1633
		1634	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1635	sometimes, fall back to using an absolue path.
1401		1636
1402	=head2 IO::AIO::REQ CLASS	1637	=head2 IO::AIO::REQ CLASS
1403		1638
1404	All non-aggregate C<aio_*> functions return an object of this class when	1639	All non-aggregate C<aio_*> functions return an object of this class when
1405	called in non-void context.	1640	called in non-void context.
…		…
1583		1818
1584	See C<poll_cb> for an example.	1819	See C<poll_cb> for an example.
1585		1820
1586	=item IO::AIO::poll_cb	1821	=item IO::AIO::poll_cb
1587		1822
1588	Process some outstanding events on the result pipe. You have to call	1823	Process some requests that have reached the result phase (i.e. they have
		1824	been executed but the results are not yet reported). You have to call
		1825	this "regularly" to finish outstanding requests.
		1826
1589	this regularly. Returns C<0> if all events could be processed (or there	1827	Returns C<0> if all events could be processed (or there were no
1590	were no events to process), or C<-1> if it returned earlier for whatever	1828	events to process), or C<-1> if it returned earlier for whatever
1591	reason. Returns immediately when no events are outstanding. The amount of	1829	reason. Returns immediately when no events are outstanding. The amount
1592	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1830	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1593	C<IO::AIO::max_poll_time>.	1831	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1594		1832
1595	If not all requests were processed for whatever reason, the filehandle	1833	If not all requests were processed for whatever reason, the poll file
1596	will still be ready when C<poll_cb> returns, so normally you don't have to	1834	descriptor will still be ready when C<poll_cb> returns, so normally you
1597	do anything special to have it called later.	1835	don't have to do anything special to have it called later.
1598		1836
1599	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1837	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1600	ready, it can be beneficial to call this function from loops which submit	1838	ready, it can be beneficial to call this function from loops which submit
1601	a lot of requests, to make sure the results get processed when they become	1839	a lot of requests, to make sure the results get processed when they become
1602	available and not just when the loop is finished and the event loop takes	1840	available and not just when the loop is finished and the event loop takes
…		…
1611	poll => 'r', async => 1,	1849	poll => 'r', async => 1,
1612	cb => \&IO::AIO::poll_cb);	1850	cb => \&IO::AIO::poll_cb);
1613		1851
1614	=item IO::AIO::poll_wait	1852	=item IO::AIO::poll_wait
1615		1853
1616	If there are any outstanding requests and none of them in the result	1854	Wait until either at least one request is in the result phase or no
1617	phase, wait till the result filehandle becomes ready for reading (simply	1855	requests are outstanding anymore.
1618	does a C<select> on the filehandle. This is useful if you want to	1856
1619	synchronously wait for some requests to finish).	1857	This is useful if you want to synchronously wait for some requests to
		1858	become ready, without actually handling them.
1620		1859
1621	See C<nreqs> for an example.	1860	See C<nreqs> for an example.
1622		1861
1623	=item IO::AIO::poll	1862	=item IO::AIO::poll
1624		1863
…		…
1745		1984
1746	This is a very bad function to use in interactive programs because it	1985	This is a very bad function to use in interactive programs because it
1747	blocks, and a bad way to reduce concurrency because it is inexact: Better	1986	blocks, and a bad way to reduce concurrency because it is inexact: Better
1748	use an C<aio_group> together with a feed callback.	1987	use an C<aio_group> together with a feed callback.
1749		1988
1750	It's main use is in scripts without an event loop - when you want to stat	1989	Its main use is in scripts without an event loop - when you want to stat
1751	a lot of files, you can write somehting like this:	1990	a lot of files, you can write somehting like this:
1752		1991
1753	IO::AIO::max_outstanding 32;	1992	IO::AIO::max_outstanding 32;
1754		1993
1755	for my $path (...) {	1994	for my $path (...) {
…		…
1795		2034
1796	=back	2035	=back
1797		2036
1798	=head3 MISCELLANEOUS FUNCTIONS	2037	=head3 MISCELLANEOUS FUNCTIONS
1799		2038
1800	IO::AIO implements some functions that might be useful, but are not	2039	IO::AIO implements some functions that are useful when you want to use
1801	asynchronous.	2040	some "Advanced I/O" function not available to in Perl, without going the
		2041	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2042	counterpart.
1802		2043
1803	=over 4	2044	=over 4
1804		2045
1805	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2046	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1806		2047
…		…
1825	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2066	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1826		2067
1827	Simply calls the C<posix_madvise> function (see its	2068	Simply calls the C<posix_madvise> function (see its
1828	manpage for details). The following advice constants are	2069	manpage for details). The following advice constants are
1829	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2070	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1830	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2071	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>,
		2072	C<IO::AIO::MADV_FREE>.
1831		2073
1832	On systems that do not implement C<posix_madvise>, this function returns	2074	On systems that do not implement C<posix_madvise>, this function returns
1833	ENOSYS, otherwise the return value of C<posix_madvise>.	2075	ENOSYS, otherwise the return value of C<posix_madvise>.
1834		2076
1835	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2077	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1843	ENOSYS, otherwise the return value of C<mprotect>.	2085	ENOSYS, otherwise the return value of C<mprotect>.
1844		2086
1845	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2087	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1846		2088
1847	Memory-maps a file (or anonymous memory range) and attaches it to the	2089	Memory-maps a file (or anonymous memory range) and attaches it to the
1848	given C<$scalar>, which will act like a string scalar.	2090	given C<$scalar>, which will act like a string scalar. Returns true on
		2091	success, and false otherwise.
1849		2092
		2093	The scalar must exist, but its contents do not matter - this means you
		2094	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2095	the scalar first.
		2096
1850	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2097	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1851	change the string length, and most read-only operations such as copying it	2098	which don't change the string length, and most read-only operations such
1852	or searching it with regexes and so on.	2099	as copying it or searching it with regexes and so on.
1853		2100
1854	Anything else is unsafe and will, at best, result in memory leaks.	2101	Anything else is unsafe and will, at best, result in memory leaks.
1855		2102
1856	The memory map associated with the C<$scalar> is automatically removed	2103	The memory map associated with the C<$scalar> is automatically removed
1857	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2104	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1858	C<IO::AIO::munmap> functions are called.	2105	or C<IO::AIO::munmap> functions are called on it.
1859		2106
1860	This calls the C<mmap>(2) function internally. See your system's manual	2107	This calls the C<mmap>(2) function internally. See your system's manual
1861	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2108	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1862		2109
1863	The C<$length> must be larger than zero and smaller than the actual	2110	The C<$length> must be larger than zero and smaller than the actual
1864	filesize.	2111	filesize.
1865		2112
1866	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2113	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1867	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2114	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1868		2115
1869	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2116	C<$flags> can be a combination of
1870	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2117	C<IO::AIO::MAP_SHARED> or
1871	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2118	C<IO::AIO::MAP_PRIVATE>,
		2119	or a number of system-specific flags (when not available, the are C<0>):
1872	(which is set to C<MAP_ANON> if your system only provides this	2120	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1873	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2121	C<IO::AIO::MAP_LOCKED>,
1874	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2122	C<IO::AIO::MAP_NORESERVE>,
		2123	C<IO::AIO::MAP_POPULATE>,
1875	C<IO::AIO::MAP_NONBLOCK>	2124	C<IO::AIO::MAP_NONBLOCK>,
		2125	C<IO::AIO::MAP_FIXED>,
		2126	C<IO::AIO::MAP_GROWSDOWN>,
		2127	C<IO::AIO::MAP_32BIT>,
		2128	C<IO::AIO::MAP_HUGETLB> or
		2129	C<IO::AIO::MAP_STACK>.
1876		2130
1877	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2131	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1878		2132
1879	C<$offset> is the offset from the start of the file - it generally must be	2133	C<$offset> is the offset from the start of the file - it generally must be
1880	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2134	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1905		2159
1906	Calls the C<munlockall> function.	2160	Calls the C<munlockall> function.
1907		2161
1908	On systems that do not implement C<munlockall>, this function returns	2162	On systems that do not implement C<munlockall>, this function returns
1909	ENOSYS, otherwise the return value of C<munlockall>.	2163	ENOSYS, otherwise the return value of C<munlockall>.
		2164
		2165	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2166
		2167	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2168	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2169	should be the file offset.
		2170
		2171	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2172	silently corrupt the data in this case.
		2173
		2174	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2175	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2176	C<IO::AIO::SPLICE_F_GIFT>.
		2177
		2178	See the C<splice(2)> manpage for details.
		2179
		2180	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2181
		2182	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2183	description for C<IO::AIO::splice> above for details.
		2184
		2185	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2186
		2187	Attempts to query or change the pipe buffer size. Obviously works only
		2188	on pipes, and currently works only on GNU/Linux systems, and fails with
		2189	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2190	size on other systems, drop me a note.
		2191
		2192	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2193
		2194	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2195	C<$flags> is missing or C<0>, then this should be the same as a call to
		2196	perl's built-in C<pipe> function and create a new pipe, and works on
		2197	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2198	(..., 4096, O_BINARY)>.
		2199
		2200	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2201	the given flags (Linux 2.6.27, glibc 2.9).
		2202
		2203	On success, the read and write file handles are returned.
		2204
		2205	On error, nothing will be returned. If the pipe2 syscall is missing and
		2206	C<$flags> is non-zero, fails with C<ENOSYS>.
		2207
		2208	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2209	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2210	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1910		2211
1911	=back	2212	=back
1912		2213
1913	=cut	2214	=cut
1914		2215

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.217 by root, Sun Oct 9 22:25:00 2011 UTC vs. Revision 1.268 by root, Tue May 30 22:45:52 2017 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.217 by root, Sun Oct 9 22:25:00 2011 UTC vs.
Revision 1.268 by root, Tue May 30 22:45:52 2017 UTC