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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.215 by root, Tue Oct 4 18:22:37 2011 UTC vs.
Revision 1.276 by root, Fri Sep 22 05:24:41 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
…		…
238	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	245	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
239	aio_load $pathname, $data, $callback->($status)	246	aio_load $pathname, $data, $callback->($status)
240	aio_copy $srcpath, $dstpath, $callback->($status)	247	aio_copy $srcpath, $dstpath, $callback->($status)
241	aio_move $srcpath, $dstpath, $callback->($status)	248	aio_move $srcpath, $dstpath, $callback->($status)
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->()
…		…
268	IO::AIO::idle_timeout $seconds	277	IO::AIO::idle_timeout $seconds
269	IO::AIO::max_outstanding $maxreqs	278	IO::AIO::max_outstanding $maxreqs
270	IO::AIO::nreqs	279	IO::AIO::nreqs
271	IO::AIO::nready	280	IO::AIO::nready
272	IO::AIO::npending	281	IO::AIO::npending
		282	IO::AIO::min_fdlimit $nfd;
273		283
274	IO::AIO::sendfile $ofh, $ifh, $offset, $count	284	IO::AIO::sendfile $ofh, $ifh, $offset, $count
275	IO::AIO::fadvise $fh, $offset, $len, $advice	285	IO::AIO::fadvise $fh, $offset, $len, $advice
		286	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		287	IO::AIO::munmap $scalar
276	IO::AIO::madvise $scalar, $offset, $length, $advice	288	IO::AIO::madvise $scalar, $offset, $length, $advice
277	IO::AIO::mprotect $scalar, $offset, $length, $protect	289	IO::AIO::mprotect $scalar, $offset, $length, $protect
278	IO::AIO::munlock $scalar, $offset = 0, $length = undef	290	IO::AIO::munlock $scalar, $offset = 0, $length = undef
279	IO::AIO::munlockall	291	IO::AIO::munlockall
280		292
281	=head2 AIO REQUEST FUNCTIONS	293	=head2 API NOTES
282		294
283	All the C<aio_*> calls are more or less thin wrappers around the syscall	295	All the C<aio_*> calls are more or less thin wrappers around the syscall
284	with the same name (sans C<aio_>). The arguments are similar or identical,	296	with the same name (sans C<aio_>). The arguments are similar or identical,
285	and they all accept an additional (and optional) C<$callback> argument	297	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	298	which must be a code reference. This code reference will be called after
…		…
317	correct contents.	329	correct contents.
318		330
319	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	331	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
320	handles correctly whether it is set or not.	332	handles correctly whether it is set or not.
321		333
		334	=head2 AIO REQUEST FUNCTIONS
		335
322	=over 4	336	=over 4
323		337
324	=item $prev_pri = aioreq_pri [$pri]	338	=item $prev_pri = aioreq_pri [$pri]
325		339
326	Returns the priority value that would be used for the next request and, if	340	Returns the priority value that would be used for the next request and, if
…		…
355		369
356		370
357	=item aio_open $pathname, $flags, $mode, $callback->($fh)	371	=item aio_open $pathname, $flags, $mode, $callback->($fh)
358		372
359	Asynchronously open or create a file and call the callback with a newly	373	Asynchronously open or create a file and call the callback with a newly
360	created filehandle for the file.	374	created filehandle for the file (or C<undef> in case of an error).
361		375
362	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	376	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
363	for an explanation.	377	for an explanation.
364		378
365	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	379	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
388	following POSIX and non-POSIX constants are available (missing ones on	402	following POSIX and non-POSIX constants are available (missing ones on
389	your system are, as usual, C<0>):	403	your system are, as usual, C<0>):
390		404
391	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	405	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>,	406	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>.	407	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
394		408
395		409
396	=item aio_close $fh, $callback->($status)	410	=item aio_close $fh, $callback->($status)
397		411
398	Asynchronously close a file and call the callback with the result	412	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	422	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.	423	free for reuse until the perl filehandle is closed.
410		424
411	=cut	425	=cut
412		426
		427	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		428
		429	Seeks the filehandle to the new C<$offset>, similarly to perl's
		430	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		431	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		432	C<IO::AIO::SEEK_END>).
		433
		434	The resulting absolute offset will be passed to the callback, or C<-1> in
		435	case of an error.
		436
		437	In theory, the C<$whence> constants could be different than the
		438	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		439	so don't panic.
		440
		441	As a GNU/Linux (and maybe Solaris) extension, also the constants
		442	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		443	could be found. No guarantees about suitability for use in C<aio_seek> or
		444	Perl's C<sysseek> can be made though, although I would naively assume they
		445	"just work".
		446
413	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	447	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
414		448
415	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	449	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416		450
417	Reads or writes C<$length> bytes from or to the specified C<$fh> and	451	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<$dataoffset>	452	C<$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	453	calls the callback with the actual number of bytes transferred (or -1 on
420	error, just like the syscall).	454	error, just like the syscall).
421		455
422	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	456	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
423	offset plus the actual number of bytes read.	457	offset plus the actual number of bytes read.
424		458
…		…
482	As native sendfile syscalls (as practically any non-POSIX interface hacked	516	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	517	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	518	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,	519	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> -	520	so you really really should check the return value of C<aio_sendfile> -
487	fewre bytes than expected might have been transferred.	521	fewer bytes than expected might have been transferred.
488		522
489		523
490	=item aio_readahead $fh,$offset,$length, $callback->($retval)	524	=item aio_readahead $fh,$offset,$length, $callback->($retval)
491		525
492	C<aio_readahead> populates the page cache with data from a file so that	526	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	530	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	531	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	532	(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.	533	file. The current file offset of the file is left unchanged.
500		534
501	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	535	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.	536	be emulated by simply reading the data, which would have a similar effect.
503		537
504		538
505	=item aio_stat $fh_or_path, $callback->($status)	539	=item aio_stat $fh_or_path, $callback->($status)
506		540
507	=item aio_lstat $fh, $callback->($status)	541	=item aio_lstat $fh, $callback->($status)
…		…
576	namemax => 255,	610	namemax => 255,
577	frsize => 1024,	611	frsize => 1024,
578	fsid => 1810	612	fsid => 1810
579	}	613	}
580		614
		615	Here is a (likely partial - send me updates!) list of fsid values used by
		616	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		617
		618	0x0000adf5 adfs
		619	0x0000adff affs
		620	0x5346414f afs
		621	0x09041934 anon-inode filesystem
		622	0x00000187 autofs
		623	0x42465331 befs
		624	0x1badface bfs
		625	0x42494e4d binfmt_misc
		626	0x9123683e btrfs
		627	0x0027e0eb cgroupfs
		628	0xff534d42 cifs
		629	0x73757245 coda
		630	0x012ff7b7 coh
		631	0x28cd3d45 cramfs
		632	0x453dcd28 cramfs-wend (wrong endianness)
		633	0x64626720 debugfs
		634	0x00001373 devfs
		635	0x00001cd1 devpts
		636	0x0000f15f ecryptfs
		637	0x00414a53 efs
		638	0x0000137d ext
		639	0x0000ef53 ext2/ext3/ext4
		640	0x0000ef51 ext2
		641	0xf2f52010 f2fs
		642	0x00004006 fat
		643	0x65735546 fuseblk
		644	0x65735543 fusectl
		645	0x0bad1dea futexfs
		646	0x01161970 gfs2
		647	0x47504653 gpfs
		648	0x00004244 hfs
		649	0xf995e849 hpfs
		650	0x00c0ffee hostfs
		651	0x958458f6 hugetlbfs
		652	0x2bad1dea inotifyfs
		653	0x00009660 isofs
		654	0x000072b6 jffs2
		655	0x3153464a jfs
		656	0x6b414653 k-afs
		657	0x0bd00bd0 lustre
		658	0x0000137f minix
		659	0x0000138f minix 30 char names
		660	0x00002468 minix v2
		661	0x00002478 minix v2 30 char names
		662	0x00004d5a minix v3
		663	0x19800202 mqueue
		664	0x00004d44 msdos
		665	0x0000564c novell
		666	0x00006969 nfs
		667	0x6e667364 nfsd
		668	0x00003434 nilfs
		669	0x5346544e ntfs
		670	0x00009fa1 openprom
		671	0x7461636F ocfs2
		672	0x00009fa0 proc
		673	0x6165676c pstorefs
		674	0x0000002f qnx4
		675	0x68191122 qnx6
		676	0x858458f6 ramfs
		677	0x52654973 reiserfs
		678	0x00007275 romfs
		679	0x67596969 rpc_pipefs
		680	0x73636673 securityfs
		681	0xf97cff8c selinux
		682	0x0000517b smb
		683	0x534f434b sockfs
		684	0x73717368 squashfs
		685	0x62656572 sysfs
		686	0x012ff7b6 sysv2
		687	0x012ff7b5 sysv4
		688	0x01021994 tmpfs
		689	0x15013346 udf
		690	0x00011954 ufs
		691	0x54190100 ufs byteswapped
		692	0x00009fa2 usbdevfs
		693	0x01021997 v9fs
		694	0xa501fcf5 vxfs
		695	0xabba1974 xenfs
		696	0x012ff7b4 xenix
		697	0x58465342 xfs
		698	0x012fd16d xia
581		699
582	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	700	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
583		701
584	Works like perl's C<utime> function (including the special case of $atime	702	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	703	and $mtime being undef). Fractional times are supported if the underlying
…		…
613	=item aio_truncate $fh_or_path, $offset, $callback->($status)	731	=item aio_truncate $fh_or_path, $offset, $callback->($status)
614		732
615	Works like truncate(2) or ftruncate(2).	733	Works like truncate(2) or ftruncate(2).
616		734
617		735
		736	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		737
		738	Allocates or frees disk space according to the C<$mode> argument. See the
		739	linux C<fallocate> documentation for details.
		740
		741	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		742	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		743	to deallocate a file range.
		744
		745	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		746	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		747	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		748	to unshare shared blocks (see your L<fallocate(2)> manpage).
		749
		750	The file system block size used by C<fallocate> is presumably the
		751	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		752	can dictate other limitations.
		753
		754	If C<fallocate> isn't available or cannot be emulated (currently no
		755	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		756
		757
618	=item aio_chmod $fh_or_path, $mode, $callback->($status)	758	=item aio_chmod $fh_or_path, $mode, $callback->($status)
619		759
620	Works like perl's C<chmod> function.	760	Works like perl's C<chmod> function.
621		761
622		762
…		…
659		799
660		800
661	=item aio_realpath $pathname, $callback->($path)	801	=item aio_realpath $pathname, $callback->($path)
662		802
663	Asynchronously make the path absolute and resolve any symlinks in	803	Asynchronously make the path absolute and resolve any symlinks in
664	C<$path>. The resulting path only consists of directories (Same as	804	C<$path>. The resulting path only consists of directories (same as
665	L<Cwd::realpath>).	805	L<Cwd::realpath>).
666		806
667	This request can be used to get the absolute path of the current working	807	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).	808	directory by passing it a path of F<.> (a single dot).
669		809
670		810
671	=item aio_rename $srcpath, $dstpath, $callback->($status)	811	=item aio_rename $srcpath, $dstpath, $callback->($status)
672		812
673	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	813	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
674	rename(2) and call the callback with the result code.	814	rename(2) and call the callback with the result code.
		815
		816	On systems that support the AIO::WD working directory abstraction
		817	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		818	of failing, C<rename> is called on the absolute path of C<$wd>.
		819
		820
		821	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		822
		823	Basically a version of C<aio_rename> with an additional C<$flags>
		824	argument. Calling this with C<$flags=0> is the same as calling
		825	C<aio_rename>.
		826
		827	Non-zero flags are currently only supported on GNU/Linux systems that
		828	support renameat2. Other systems fail with C<ENOSYS> in this case.
		829
		830	The following constants are available (missing ones are, as usual C<0>),
		831	see renameat2(2) for details:
		832
		833	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		834	and C<IO::AIO::RENAME_WHITEOUT>.
675		835
676		836
677	=item aio_mkdir $pathname, $mode, $callback->($status)	837	=item aio_mkdir $pathname, $mode, $callback->($status)
678		838
679	Asynchronously mkdir (create) a directory and call the callback with	839	Asynchronously mkdir (create) a directory and call the callback with
…		…
683		843
684	=item aio_rmdir $pathname, $callback->($status)	844	=item aio_rmdir $pathname, $callback->($status)
685		845
686	Asynchronously rmdir (delete) a directory and call the callback with the	846	Asynchronously rmdir (delete) a directory and call the callback with the
687	result code.	847	result code.
		848
		849	On systems that support the AIO::WD working directory abstraction
		850	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		851	C<rmdir> is called on the absolute path of C<$wd>.
688		852
689		853
690	=item aio_readdir $pathname, $callback->($entries)	854	=item aio_readdir $pathname, $callback->($entries)
691		855
692	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	856	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
…		…
794	=item aio_copy $srcpath, $dstpath, $callback->($status)	958	=item aio_copy $srcpath, $dstpath, $callback->($status)
795		959
796	Try to copy the I<file> (directories not supported as either source or	960	Try to copy the I<file> (directories not supported as either source or
797	destination) from C<$srcpath> to C<$dstpath> and call the callback with	961	destination) from C<$srcpath> to C<$dstpath> and call the callback with
798	a status of C<0> (ok) or C<-1> (error, see C<$!>).	962	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		963
		964	Existing destination files will be truncated.
799		965
800	This is a composite request that creates the destination file with	966	This is a composite request that creates the destination file with
801	mode 0200 and copies the contents of the source file into it using	967	mode 0200 and copies the contents of the source file into it using
802	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	968	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
803	uid/gid, in that order.	969	uid/gid, in that order.
…		…
1057	}	1223	}
1058		1224
1059	=item aio_rmtree $pathname, $callback->($status)	1225	=item aio_rmtree $pathname, $callback->($status)
1060		1226
1061	Delete a directory tree starting (and including) C<$path>, return the	1227	Delete a directory tree starting (and including) C<$path>, return the
1062	status of the final C<rmdir> only. This is a composite request that	1228	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	1229	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1064	everything else.	1230	everything else.
1065		1231
1066	=cut	1232	=cut
1067		1233
…		…
1088	add $grp $dirgrp;	1254	add $grp $dirgrp;
1089	};	1255	};
1090		1256
1091	$grp	1257	$grp
1092	}	1258	}
		1259
		1260	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1261
		1262	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1263
		1264	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1265	they execute asynchronously and pass the return value to the callback.
		1266
		1267	Both calls can be used for a lot of things, some of which make more sense
		1268	to run asynchronously in their own thread, while some others make less
		1269	sense. For example, calls that block waiting for external events, such
		1270	as locking, will also lock down an I/O thread while it is waiting, which
		1271	can deadlock the whole I/O system. At the same time, there might be no
		1272	alternative to using a thread to wait.
		1273
		1274	So in general, you should only use these calls for things that do
		1275	(filesystem) I/O, not for things that wait for other events (network,
		1276	other processes), although if you are careful and know what you are doing,
		1277	you still can.
		1278
		1279	The following constants are available (missing ones are, as usual C<0>):
		1280
		1281	C<F_DUPFD_CLOEXEC>,
		1282
		1283	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1284
		1285	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1286
		1287	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1288	C<FS_IOC_FIEMAP>.
		1289
		1290	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1291	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1292
		1293	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1294	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1295	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1296	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1297	C<FS_FL_USER_MODIFIABLE>.
		1298
		1299	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1300	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1301	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1302	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1093		1303
1094	=item aio_sync $callback->($status)	1304	=item aio_sync $callback->($status)
1095		1305
1096	Asynchronously call sync and call the callback when finished.	1306	Asynchronously call sync and call the callback when finished.
1097		1307
…		…
1166	};	1376	};
1167		1377
1168	$grp	1378	$grp
1169	}	1379	}
1170		1380
1171	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1381	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1172		1382
1173	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1383	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	1384	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	1385	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	1386	scalar must only be modified in-place while an aio operation is pending on
…		…
1178		1388
1179	It calls the C<msync> function of your OS, if available, with the memory	1389	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	1390	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>	1391	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	1392	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	1393	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1184	C<IO::AIO::MS_SYNC>.	1394	C<IO::AIO::MS_INVALIDATE>.
1185		1395
1186	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1396	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1187		1397
1188	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1398	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1189	scalars.	1399	scalars.
1190		1400
1191	It touches (reads or writes) all memory pages in the specified	1401	It touches (reads or writes) all memory pages in the specified
1192	range inside the scalar. All caveats and parameters are the same	1402	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	1403	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	1404	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	1405	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1196	writing an octet from it, which dirties the page).	1406	writing an octet from it, which dirties the page).
1197		1407
1198	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1408	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1199		1409
1200	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1410	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1231	documented under L<MISCELLANEOUS FUNCTIONS>.	1441	documented under L<MISCELLANEOUS FUNCTIONS>.
1232		1442
1233	Example: asynchronously lock all current and future pages into memory.	1443	Example: asynchronously lock all current and future pages into memory.
1234		1444
1235	aio_mlockall IO::AIO::MCL_FUTURE;	1445	aio_mlockall IO::AIO::MCL_FUTURE;
		1446
		1447	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1448
		1449	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1450	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1451	the ioctl is not available on your OS, then this request will fail with
		1452	C<ENOSYS>.
		1453
		1454	C<$start> is the starting offset to query extents for, C<$length> is the
		1455	size of the range to query - if it is C<undef>, then the whole file will
		1456	be queried.
		1457
		1458	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1459	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1460	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1461	the data portion.
		1462
		1463	C<$count> is the maximum number of extent records to return. If it is
		1464	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1465	case, if it is C<0>, then the callback receives the number of extents
		1466	instead of the extents themselves (which is unreliable, see below).
		1467
		1468	If an error occurs, the callback receives no arguments. The special
		1469	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1470
		1471	Otherwise, the callback receives an array reference with extent
		1472	structures. Each extent structure is an array reference itself, with the
		1473	following members:
		1474
		1475	[$logical, $physical, $length, $flags]
		1476
		1477	Flags is any combination of the following flag values (typically either C<0>
		1478	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1479
		1480	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1481	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1482	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1483	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1484	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1485	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1486
		1487	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1488	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1489	it to return all extents of a range for files with large number of
		1490	extents. The code works around all these issues if C<$count> is undef.
1236		1491
1237	=item aio_group $callback->(...)	1492	=item aio_group $callback->(...)
1238		1493
1239	This is a very special aio request: Instead of doing something, it is a	1494	This is a very special aio request: Instead of doing something, it is a
1240	container for other aio requests, which is useful if you want to bundle	1495	container for other aio requests, which is useful if you want to bundle
…		…
1324	aio_stat [$etcdir, "passwd"], sub {	1579	aio_stat [$etcdir, "passwd"], sub {
1325	# yay	1580	# yay
1326	};	1581	};
1327	};	1582	};
1328		1583
1329	That C<aio_wd> is a request and not a normal function shows that creating	1584	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	1585	creating an IO::AIO::WD object is itself a potentially blocking operation,
1331	why it is done asynchronously.	1586	which is why it is done asynchronously.
1332		1587
1333	To stat the directory obtained with C<aio_wd> above, one could write	1588	To stat the directory obtained with C<aio_wd> above, one could write
1334	either of the following three request calls:	1589	either of the following three request calls:
1335		1590
1336	aio_lstat "/etc" , sub { ... # pathname as normal string	1591	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1356	will still point to the original directory. Most functions accepting a	1611	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	1612	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	1613	older systems. Some functions (such as realpath) will always rely on the
1359	string form of the pathname.	1614	string form of the pathname.
1360		1615
1361	So this fucntionality is mainly useful to get some protection against	1616	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	1617	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	1618	reference, and to speed up doing many operations in the same directory
1364	(e.g. when stat'ing all files in a directory).	1619	(e.g. when stat'ing all files in a directory).
1365		1620
1366	The following functions implement this working directory abstraction:	1621	The following functions implement this working directory abstraction:
…		…
1379	passing C<undef> as working directory component of a pathname fails the	1634	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	1635	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	1636	C<aio_wd> callback, as future requests using the value will fail in the
1382	expected way.	1637	expected way.
1383		1638
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	1639	=item IO::AIO::CWD
1388		1640
1389	This is a compiletime constant (object) that represents the process	1641	This is a compiletime constant (object) that represents the process
1390	current working directory.	1642	current working directory.
1391		1643
1392	Specifying this object as working directory object for a pathname is as	1644	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,	1645	the pathname would be specified directly, without a directory object. For
1394	e.g., these calls are functionally identical:	1646	example, these calls are functionally identical:
1395		1647
1396	aio_stat "somefile", sub { ... };	1648	aio_stat "somefile", sub { ... };
1397	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1649	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1398		1650
1399	=back	1651	=back
1400		1652
		1653	To recover the path associated with an IO::AIO::WD object, you can use
		1654	C<aio_realpath>:
		1655
		1656	aio_realpath $wd, sub {
		1657	warn "path is $_[0]\n";
		1658	};
		1659
		1660	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1661	sometimes, fall back to using an absolue path.
1401		1662
1402	=head2 IO::AIO::REQ CLASS	1663	=head2 IO::AIO::REQ CLASS
1403		1664
1404	All non-aggregate C<aio_*> functions return an object of this class when	1665	All non-aggregate C<aio_*> functions return an object of this class when
1405	called in non-void context.	1666	called in non-void context.
…		…
1583		1844
1584	See C<poll_cb> for an example.	1845	See C<poll_cb> for an example.
1585		1846
1586	=item IO::AIO::poll_cb	1847	=item IO::AIO::poll_cb
1587		1848
1588	Process some outstanding events on the result pipe. You have to call	1849	Process some requests that have reached the result phase (i.e. they have
		1850	been executed but the results are not yet reported). You have to call
		1851	this "regularly" to finish outstanding requests.
		1852
1589	this regularly. Returns C<0> if all events could be processed (or there	1853	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	1854	events to process), or C<-1> if it returned earlier for whatever
1591	reason. Returns immediately when no events are outstanding. The amount of	1855	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	1856	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1593	C<IO::AIO::max_poll_time>.	1857	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1594		1858
1595	If not all requests were processed for whatever reason, the filehandle	1859	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	1860	descriptor will still be ready when C<poll_cb> returns, so normally you
1597	do anything special to have it called later.	1861	don't have to do anything special to have it called later.
1598		1862
1599	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1863	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	1864	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	1865	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	1866	available and not just when the loop is finished and the event loop takes
…		…
1611	poll => 'r', async => 1,	1875	poll => 'r', async => 1,
1612	cb => \&IO::AIO::poll_cb);	1876	cb => \&IO::AIO::poll_cb);
1613		1877
1614	=item IO::AIO::poll_wait	1878	=item IO::AIO::poll_wait
1615		1879
1616	If there are any outstanding requests and none of them in the result	1880	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	1881	requests are outstanding anymore.
1618	does a C<select> on the filehandle. This is useful if you want to	1882
1619	synchronously wait for some requests to finish).	1883	This is useful if you want to synchronously wait for some requests to
		1884	become ready, without actually handling them.
1620		1885
1621	See C<nreqs> for an example.	1886	See C<nreqs> for an example.
1622		1887
1623	=item IO::AIO::poll	1888	=item IO::AIO::poll
1624		1889
…		…
1745		2010
1746	This is a very bad function to use in interactive programs because it	2011	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	2012	blocks, and a bad way to reduce concurrency because it is inexact: Better
1748	use an C<aio_group> together with a feed callback.	2013	use an C<aio_group> together with a feed callback.
1749		2014
1750	It's main use is in scripts without an event loop - when you want to stat	2015	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:	2016	a lot of files, you can write something like this:
1752		2017
1753	IO::AIO::max_outstanding 32;	2018	IO::AIO::max_outstanding 32;
1754		2019
1755	for my $path (...) {	2020	for my $path (...) {
1756	aio_stat $path , ...;	2021	aio_stat $path , ...;
…		…
1795		2060
1796	=back	2061	=back
1797		2062
1798	=head3 MISCELLANEOUS FUNCTIONS	2063	=head3 MISCELLANEOUS FUNCTIONS
1799		2064
1800	IO::AIO implements some functions that might be useful, but are not	2065	IO::AIO implements some functions that are useful when you want to use
1801	asynchronous.	2066	some "Advanced I/O" function not available to in Perl, without going the
		2067	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2068	counterpart.
1802		2069
1803	=over 4	2070	=over 4
		2071
		2072	=item $numfd = IO::AIO::get_fdlimit
		2073
		2074	Tries to find the current file descriptor limit and returns it, or
		2075	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2076	the highest valid file descriptor number.
		2077
		2078	=item IO::AIO::min_fdlimit [$numfd]
		2079
		2080	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2081	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2082	is missing, it will try to set a very high limit, although this is not
		2083	recommended when you know the actual minimum that you require.
		2084
		2085	If the limit cannot be raised enough, the function makes a best-effort
		2086	attempt to increase the limit as much as possible, using various
		2087	tricks, while still failing. You can query the resulting limit using
		2088	C<IO::AIO::get_fdlimit>.
		2089
		2090	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2091	true.
1804		2092
1805	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2093	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1806		2094
1807	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2095	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1808	but is blocking (this makes most sense if you know the input data is	2096	but is blocking (this makes most sense if you know the input data is
…		…
1825	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2113	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1826		2114
1827	Simply calls the C<posix_madvise> function (see its	2115	Simply calls the C<posix_madvise> function (see its
1828	manpage for details). The following advice constants are	2116	manpage for details). The following advice constants are
1829	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2117	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1830	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2118	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2119	C<IO::AIO::MADV_DONTNEED>.
		2120
		2121	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2122	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2123	will be reduced to fit into the C<$scalar>.
1831		2124
1832	On systems that do not implement C<posix_madvise>, this function returns	2125	On systems that do not implement C<posix_madvise>, this function returns
1833	ENOSYS, otherwise the return value of C<posix_madvise>.	2126	ENOSYS, otherwise the return value of C<posix_madvise>.
1834		2127
1835	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2128	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1837	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2130	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1838	$scalar (see its manpage for details). The following protect	2131	$scalar (see its manpage for details). The following protect
1839	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2132	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1840	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2133	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1841		2134
		2135	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2136	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2137	will be reduced to fit into the C<$scalar>.
		2138
1842	On systems that do not implement C<mprotect>, this function returns	2139	On systems that do not implement C<mprotect>, this function returns
1843	ENOSYS, otherwise the return value of C<mprotect>.	2140	ENOSYS, otherwise the return value of C<mprotect>.
1844		2141
1845	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2142	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1846		2143
1847	Memory-maps a file (or anonymous memory range) and attaches it to the	2144	Memory-maps a file (or anonymous memory range) and attaches it to the
1848	given C<$scalar>, which will act like a string scalar.	2145	given C<$scalar>, which will act like a string scalar. Returns true on
		2146	success, and false otherwise.
1849		2147
		2148	The scalar must exist, but its contents do not matter - this means you
		2149	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2150	the scalar first.
		2151
1850	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2152	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1851	change the string length, and most read-only operations such as copying it	2153	which don't change the string length, and most read-only operations such
1852	or searching it with regexes and so on.	2154	as copying it or searching it with regexes and so on.
1853		2155
1854	Anything else is unsafe and will, at best, result in memory leaks.	2156	Anything else is unsafe and will, at best, result in memory leaks.
1855		2157
1856	The memory map associated with the C<$scalar> is automatically removed	2158	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	2159	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1858	C<IO::AIO::munmap> functions are called.	2160	or C<IO::AIO::munmap> functions are called on it.
1859		2161
1860	This calls the C<mmap>(2) function internally. See your system's manual	2162	This calls the C<mmap>(2) function internally. See your system's manual
1861	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2163	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1862		2164
1863	The C<$length> must be larger than zero and smaller than the actual	2165	The C<$length> must be larger than zero and smaller than the actual
1864	filesize.	2166	filesize.
1865		2167
1866	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2168	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1867	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2169	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1868		2170
1869	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2171	C<$flags> can be a combination of
1870	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2172	C<IO::AIO::MAP_SHARED> or
1871	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2173	C<IO::AIO::MAP_PRIVATE>,
		2174	or a number of system-specific flags (when not available, the are C<0>):
1872	(which is set to C<MAP_ANON> if your system only provides this	2175	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1873	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2176	C<IO::AIO::MAP_LOCKED>,
1874	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2177	C<IO::AIO::MAP_NORESERVE>,
		2178	C<IO::AIO::MAP_POPULATE>,
1875	C<IO::AIO::MAP_NONBLOCK>	2179	C<IO::AIO::MAP_NONBLOCK>,
		2180	C<IO::AIO::MAP_FIXED>,
		2181	C<IO::AIO::MAP_GROWSDOWN>,
		2182	C<IO::AIO::MAP_32BIT>,
		2183	C<IO::AIO::MAP_HUGETLB> or
		2184	C<IO::AIO::MAP_STACK>.
1876		2185
1877	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2186	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1878		2187
1879	C<$offset> is the offset from the start of the file - it generally must be	2188	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>.	2189	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1905		2214
1906	Calls the C<munlockall> function.	2215	Calls the C<munlockall> function.
1907		2216
1908	On systems that do not implement C<munlockall>, this function returns	2217	On systems that do not implement C<munlockall>, this function returns
1909	ENOSYS, otherwise the return value of C<munlockall>.	2218	ENOSYS, otherwise the return value of C<munlockall>.
		2219
		2220	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2221
		2222	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2223	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2224	should be the file offset.
		2225
		2226	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2227	silently corrupt the data in this case.
		2228
		2229	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2230	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2231	C<IO::AIO::SPLICE_F_GIFT>.
		2232
		2233	See the C<splice(2)> manpage for details.
		2234
		2235	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2236
		2237	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2238	description for C<IO::AIO::splice> above for details.
		2239
		2240	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2241
		2242	Attempts to query or change the pipe buffer size. Obviously works only
		2243	on pipes, and currently works only on GNU/Linux systems, and fails with
		2244	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2245	size on other systems, drop me a note.
		2246
		2247	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2248
		2249	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2250	C<$flags> is missing or C<0>, then this should be the same as a call to
		2251	perl's built-in C<pipe> function and create a new pipe, and works on
		2252	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2253	(..., 4096, O_BINARY)>.
		2254
		2255	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2256	the given flags (Linux 2.6.27, glibc 2.9).
		2257
		2258	On success, the read and write file handles are returned.
		2259
		2260	On error, nothing will be returned. If the pipe2 syscall is missing and
		2261	C<$flags> is non-zero, fails with C<ENOSYS>.
		2262
		2263	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2264	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2265	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1910		2266
1911	=back	2267	=back
1912		2268
1913	=cut	2269	=cut
1914		2270

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.215 by root, Tue Oct 4 18:22:37 2011 UTC vs. Revision 1.276 by root, Fri Sep 22 05:24:41 2017 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.215 by root, Tue Oct 4 18:22:37 2011 UTC vs.
Revision 1.276 by root, Fri Sep 22 05:24:41 2017 UTC