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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.223 by root, Fri Apr 6 22:51:02 2012 UTC vs.
Revision 1.278 by root, Sun Oct 1 07:24:34 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 = '4.13';	176	our $VERSION = 4.35;
174		177
175	our @AIO_REQ = qw(aio_sendfile aio_seek 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 aio_fiemap	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)
…		…
221	aio_statvfs $fh_or_path, $callback->($statvfs)	224	aio_statvfs $fh_or_path, $callback->($statvfs)
222	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	225	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
223	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	226	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224	aio_chmod $fh_or_path, $mode, $callback->($status)	227	aio_chmod $fh_or_path, $mode, $callback->($status)
225	aio_truncate $fh_or_path, $offset, $callback->($status)	228	aio_truncate $fh_or_path, $offset, $callback->($status)
		229	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		230	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
226	aio_unlink $pathname, $callback->($status)	231	aio_unlink $pathname, $callback->($status)
227	aio_mknod $pathname, $mode, $dev, $callback->($status)	232	aio_mknod $pathname, $mode, $dev, $callback->($status)
228	aio_link $srcpath, $dstpath, $callback->($status)	233	aio_link $srcpath, $dstpath, $callback->($status)
229	aio_symlink $srcpath, $dstpath, $callback->($status)	234	aio_symlink $srcpath, $dstpath, $callback->($status)
230	aio_readlink $pathname, $callback->($link)	235	aio_readlink $pathname, $callback->($link)
231	aio_realpath $pathname, $callback->($link)	236	aio_realpath $pathname, $callback->($path)
232	aio_rename $srcpath, $dstpath, $callback->($status)	237	aio_rename $srcpath, $dstpath, $callback->($status)
		238	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
233	aio_mkdir $pathname, $mode, $callback->($status)	239	aio_mkdir $pathname, $mode, $callback->($status)
234	aio_rmdir $pathname, $callback->($status)	240	aio_rmdir $pathname, $callback->($status)
235	aio_readdir $pathname, $callback->($entries)	241	aio_readdir $pathname, $callback->($entries)
236	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	242	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
237	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	243	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
…		…
239	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	245	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
240	aio_load $pathname, $data, $callback->($status)	246	aio_load $pathname, $data, $callback->($status)
241	aio_copy $srcpath, $dstpath, $callback->($status)	247	aio_copy $srcpath, $dstpath, $callback->($status)
242	aio_move $srcpath, $dstpath, $callback->($status)	248	aio_move $srcpath, $dstpath, $callback->($status)
243	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)
244	aio_sync $callback->($status)	252	aio_sync $callback->($status)
245	aio_syncfs $fh, $callback->($status)	253	aio_syncfs $fh, $callback->($status)
246	aio_fsync $fh, $callback->($status)	254	aio_fsync $fh, $callback->($status)
247	aio_fdatasync $fh, $callback->($status)	255	aio_fdatasync $fh, $callback->($status)
248	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	256	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
249	aio_pathsync $pathname, $callback->($status)	257	aio_pathsync $pathname, $callback->($status)
250	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	258	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
251	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
252	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	260	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
253	aio_mlockall $flags, $callback->($status)	261	aio_mlockall $flags, $callback->($status)
254	aio_group $callback->(...)	262	aio_group $callback->(...)
255	aio_nop $callback->()	263	aio_nop $callback->()
…		…
269	IO::AIO::idle_timeout $seconds	277	IO::AIO::idle_timeout $seconds
270	IO::AIO::max_outstanding $maxreqs	278	IO::AIO::max_outstanding $maxreqs
271	IO::AIO::nreqs	279	IO::AIO::nreqs
272	IO::AIO::nready	280	IO::AIO::nready
273	IO::AIO::npending	281	IO::AIO::npending
		282	$nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
		283	IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
274		284
275	IO::AIO::sendfile $ofh, $ifh, $offset, $count	285	IO::AIO::sendfile $ofh, $ifh, $offset, $count
276	IO::AIO::fadvise $fh, $offset, $len, $advice	286	IO::AIO::fadvise $fh, $offset, $len, $advice
		287	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		288	IO::AIO::munmap $scalar
277	IO::AIO::madvise $scalar, $offset, $length, $advice	289	IO::AIO::madvise $scalar, $offset, $length, $advice
278	IO::AIO::mprotect $scalar, $offset, $length, $protect	290	IO::AIO::mprotect $scalar, $offset, $length, $protect
279	IO::AIO::munlock $scalar, $offset = 0, $length = undef	291	IO::AIO::munlock $scalar, $offset = 0, $length = undef
280	IO::AIO::munlockall	292	IO::AIO::munlockall
281		293
…		…
358		370
359		371
360	=item aio_open $pathname, $flags, $mode, $callback->($fh)	372	=item aio_open $pathname, $flags, $mode, $callback->($fh)
361		373
362	Asynchronously open or create a file and call the callback with a newly	374	Asynchronously open or create a file and call the callback with a newly
363	created filehandle for the file.	375	created filehandle for the file (or C<undef> in case of an error).
364		376
365	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	377	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
366	for an explanation.	378	for an explanation.
367		379
368	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	380	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
391	following POSIX and non-POSIX constants are available (missing ones on	403	following POSIX and non-POSIX constants are available (missing ones on
392	your system are, as usual, C<0>):	404	your system are, as usual, C<0>):
393		405
394	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	406	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
395	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	407	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
396	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	408	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
397		409
398		410
399	=item aio_close $fh, $callback->($status)	411	=item aio_close $fh, $callback->($status)
400		412
401	Asynchronously close a file and call the callback with the result	413	Asynchronously close a file and call the callback with the result
…		…
425		437
426	In theory, the C<$whence> constants could be different than the	438	In theory, the C<$whence> constants could be different than the
427	corresponding values from L<Fcntl>, but perl guarantees they are the same,	439	corresponding values from L<Fcntl>, but perl guarantees they are the same,
428	so don't panic.	440	so don't panic.
429		441
		442	As a GNU/Linux (and maybe Solaris) extension, also the constants
		443	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		444	could be found. No guarantees about suitability for use in C<aio_seek> or
		445	Perl's C<sysseek> can be made though, although I would naively assume they
		446	"just work".
		447
430	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	448	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
431		449
432	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	450	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
433		451
434	Reads or writes C<$length> bytes from or to the specified C<$fh> and	452	Reads or writes C<$length> bytes from or to the specified C<$fh> and
435	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	453	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
436	and calls the callback without the actual number of bytes read (or -1 on	454	calls the callback with the actual number of bytes transferred (or -1 on
437	error, just like the syscall).	455	error, just like the syscall).
438		456
439	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	457	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
440	offset plus the actual number of bytes read.	458	offset plus the actual number of bytes read.
441		459
…		…
499	As native sendfile syscalls (as practically any non-POSIX interface hacked	517	As native sendfile syscalls (as practically any non-POSIX interface hacked
500	together in a hurry to improve benchmark numbers) tend to be rather buggy	518	together in a hurry to improve benchmark numbers) tend to be rather buggy
501	on many systems, this implementation tries to work around some known bugs	519	on many systems, this implementation tries to work around some known bugs
502	in Linux and FreeBSD kernels (probably others, too), but that might fail,	520	in Linux and FreeBSD kernels (probably others, too), but that might fail,
503	so you really really should check the return value of C<aio_sendfile> -	521	so you really really should check the return value of C<aio_sendfile> -
504	fewre bytes than expected might have been transferred.	522	fewer bytes than expected might have been transferred.
505		523
506		524
507	=item aio_readahead $fh,$offset,$length, $callback->($retval)	525	=item aio_readahead $fh,$offset,$length, $callback->($retval)
508		526
509	C<aio_readahead> populates the page cache with data from a file so that	527	C<aio_readahead> populates the page cache with data from a file so that
…		…
513	whole pages, so that offset is effectively rounded down to a page boundary	531	whole pages, so that offset is effectively rounded down to a page boundary
514	and bytes are read up to the next page boundary greater than or equal to	532	and bytes are read up to the next page boundary greater than or equal to
515	(off-set+length). C<aio_readahead> does not read beyond the end of the	533	(off-set+length). C<aio_readahead> does not read beyond the end of the
516	file. The current file offset of the file is left unchanged.	534	file. The current file offset of the file is left unchanged.
517		535
518	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	536	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
519	emulated by simply reading the data, which would have a similar effect.	537	be emulated by simply reading the data, which would have a similar effect.
520		538
521		539
522	=item aio_stat $fh_or_path, $callback->($status)	540	=item aio_stat $fh_or_path, $callback->($status)
523		541
524	=item aio_lstat $fh, $callback->($status)	542	=item aio_lstat $fh, $callback->($status)
…		…
593	namemax => 255,	611	namemax => 255,
594	frsize => 1024,	612	frsize => 1024,
595	fsid => 1810	613	fsid => 1810
596	}	614	}
597		615
		616	Here is a (likely partial - send me updates!) list of fsid values used by
		617	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		618
		619	0x0000adf5 adfs
		620	0x0000adff affs
		621	0x5346414f afs
		622	0x09041934 anon-inode filesystem
		623	0x00000187 autofs
		624	0x42465331 befs
		625	0x1badface bfs
		626	0x42494e4d binfmt_misc
		627	0x9123683e btrfs
		628	0x0027e0eb cgroupfs
		629	0xff534d42 cifs
		630	0x73757245 coda
		631	0x012ff7b7 coh
		632	0x28cd3d45 cramfs
		633	0x453dcd28 cramfs-wend (wrong endianness)
		634	0x64626720 debugfs
		635	0x00001373 devfs
		636	0x00001cd1 devpts
		637	0x0000f15f ecryptfs
		638	0x00414a53 efs
		639	0x0000137d ext
		640	0x0000ef53 ext2/ext3/ext4
		641	0x0000ef51 ext2
		642	0xf2f52010 f2fs
		643	0x00004006 fat
		644	0x65735546 fuseblk
		645	0x65735543 fusectl
		646	0x0bad1dea futexfs
		647	0x01161970 gfs2
		648	0x47504653 gpfs
		649	0x00004244 hfs
		650	0xf995e849 hpfs
		651	0x00c0ffee hostfs
		652	0x958458f6 hugetlbfs
		653	0x2bad1dea inotifyfs
		654	0x00009660 isofs
		655	0x000072b6 jffs2
		656	0x3153464a jfs
		657	0x6b414653 k-afs
		658	0x0bd00bd0 lustre
		659	0x0000137f minix
		660	0x0000138f minix 30 char names
		661	0x00002468 minix v2
		662	0x00002478 minix v2 30 char names
		663	0x00004d5a minix v3
		664	0x19800202 mqueue
		665	0x00004d44 msdos
		666	0x0000564c novell
		667	0x00006969 nfs
		668	0x6e667364 nfsd
		669	0x00003434 nilfs
		670	0x5346544e ntfs
		671	0x00009fa1 openprom
		672	0x7461636F ocfs2
		673	0x00009fa0 proc
		674	0x6165676c pstorefs
		675	0x0000002f qnx4
		676	0x68191122 qnx6
		677	0x858458f6 ramfs
		678	0x52654973 reiserfs
		679	0x00007275 romfs
		680	0x67596969 rpc_pipefs
		681	0x73636673 securityfs
		682	0xf97cff8c selinux
		683	0x0000517b smb
		684	0x534f434b sockfs
		685	0x73717368 squashfs
		686	0x62656572 sysfs
		687	0x012ff7b6 sysv2
		688	0x012ff7b5 sysv4
		689	0x01021994 tmpfs
		690	0x15013346 udf
		691	0x00011954 ufs
		692	0x54190100 ufs byteswapped
		693	0x00009fa2 usbdevfs
		694	0x01021997 v9fs
		695	0xa501fcf5 vxfs
		696	0xabba1974 xenfs
		697	0x012ff7b4 xenix
		698	0x58465342 xfs
		699	0x012fd16d xia
598		700
599	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	701	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
600		702
601	Works like perl's C<utime> function (including the special case of $atime	703	Works like perl's C<utime> function (including the special case of $atime
602	and $mtime being undef). Fractional times are supported if the underlying	704	and $mtime being undef). Fractional times are supported if the underlying
…		…
630	=item aio_truncate $fh_or_path, $offset, $callback->($status)	732	=item aio_truncate $fh_or_path, $offset, $callback->($status)
631		733
632	Works like truncate(2) or ftruncate(2).	734	Works like truncate(2) or ftruncate(2).
633		735
634		736
		737	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		738
		739	Allocates or frees disk space according to the C<$mode> argument. See the
		740	linux C<fallocate> documentation for details.
		741
		742	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		743	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		744	to deallocate a file range.
		745
		746	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		747	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		748	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		749	to unshare shared blocks (see your L<fallocate(2)> manpage).
		750
		751	The file system block size used by C<fallocate> is presumably the
		752	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		753	can dictate other limitations.
		754
		755	If C<fallocate> isn't available or cannot be emulated (currently no
		756	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		757
		758
635	=item aio_chmod $fh_or_path, $mode, $callback->($status)	759	=item aio_chmod $fh_or_path, $mode, $callback->($status)
636		760
637	Works like perl's C<chmod> function.	761	Works like perl's C<chmod> function.
638		762
639		763
…		…
676		800
677		801
678	=item aio_realpath $pathname, $callback->($path)	802	=item aio_realpath $pathname, $callback->($path)
679		803
680	Asynchronously make the path absolute and resolve any symlinks in	804	Asynchronously make the path absolute and resolve any symlinks in
681	C<$path>. The resulting path only consists of directories (Same as	805	C<$path>. The resulting path only consists of directories (same as
682	L<Cwd::realpath>).	806	L<Cwd::realpath>).
683		807
684	This request can be used to get the absolute path of the current working	808	This request can be used to get the absolute path of the current working
685	directory by passing it a path of F<.> (a single dot).	809	directory by passing it a path of F<.> (a single dot).
686		810
687		811
688	=item aio_rename $srcpath, $dstpath, $callback->($status)	812	=item aio_rename $srcpath, $dstpath, $callback->($status)
689		813
690	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	814	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
691	rename(2) and call the callback with the result code.	815	rename(2) and call the callback with the result code.
		816
		817	On systems that support the AIO::WD working directory abstraction
		818	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		819	of failing, C<rename> is called on the absolute path of C<$wd>.
		820
		821
		822	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		823
		824	Basically a version of C<aio_rename> with an additional C<$flags>
		825	argument. Calling this with C<$flags=0> is the same as calling
		826	C<aio_rename>.
		827
		828	Non-zero flags are currently only supported on GNU/Linux systems that
		829	support renameat2. Other systems fail with C<ENOSYS> in this case.
		830
		831	The following constants are available (missing ones are, as usual C<0>),
		832	see renameat2(2) for details:
		833
		834	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		835	and C<IO::AIO::RENAME_WHITEOUT>.
692		836
693		837
694	=item aio_mkdir $pathname, $mode, $callback->($status)	838	=item aio_mkdir $pathname, $mode, $callback->($status)
695		839
696	Asynchronously mkdir (create) a directory and call the callback with	840	Asynchronously mkdir (create) a directory and call the callback with
…		…
700		844
701	=item aio_rmdir $pathname, $callback->($status)	845	=item aio_rmdir $pathname, $callback->($status)
702		846
703	Asynchronously rmdir (delete) a directory and call the callback with the	847	Asynchronously rmdir (delete) a directory and call the callback with the
704	result code.	848	result code.
		849
		850	On systems that support the AIO::WD working directory abstraction
		851	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		852	C<rmdir> is called on the absolute path of C<$wd>.
705		853
706		854
707	=item aio_readdir $pathname, $callback->($entries)	855	=item aio_readdir $pathname, $callback->($entries)
708		856
709	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	857	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
…		…
811	=item aio_copy $srcpath, $dstpath, $callback->($status)	959	=item aio_copy $srcpath, $dstpath, $callback->($status)
812		960
813	Try to copy the I<file> (directories not supported as either source or	961	Try to copy the I<file> (directories not supported as either source or
814	destination) from C<$srcpath> to C<$dstpath> and call the callback with	962	destination) from C<$srcpath> to C<$dstpath> and call the callback with
815	a status of C<0> (ok) or C<-1> (error, see C<$!>).	963	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		964
		965	Existing destination files will be truncated.
816		966
817	This is a composite request that creates the destination file with	967	This is a composite request that creates the destination file with
818	mode 0200 and copies the contents of the source file into it using	968	mode 0200 and copies the contents of the source file into it using
819	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	969	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
820	uid/gid, in that order.	970	uid/gid, in that order.
…		…
930	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1080	Scans a directory (similar to C<aio_readdir>) but additionally tries to
931	efficiently separate the entries of directory C<$path> into two sets of	1081	efficiently separate the entries of directory C<$path> into two sets of
932	names, directories you can recurse into (directories), and ones you cannot	1082	names, directories you can recurse into (directories), and ones you cannot
933	recurse into (everything else, including symlinks to directories).	1083	recurse into (everything else, including symlinks to directories).
934		1084
935	C<aio_scandir> is a composite request that creates of many sub requests_	1085	C<aio_scandir> is a composite request that generates many sub requests.
936	C<$maxreq> specifies the maximum number of outstanding aio requests that	1086	C<$maxreq> specifies the maximum number of outstanding aio requests that
937	this function generates. If it is C<< <= 0 >>, then a suitable default	1087	this function generates. If it is C<< <= 0 >>, then a suitable default
938	will be chosen (currently 4).	1088	will be chosen (currently 4).
939		1089
940	On error, the callback is called without arguments, otherwise it receives	1090	On error, the callback is called without arguments, otherwise it receives
…		…
1074	}	1224	}
1075		1225
1076	=item aio_rmtree $pathname, $callback->($status)	1226	=item aio_rmtree $pathname, $callback->($status)
1077		1227
1078	Delete a directory tree starting (and including) C<$path>, return the	1228	Delete a directory tree starting (and including) C<$path>, return the
1079	status of the final C<rmdir> only. This is a composite request that	1229	status of the final C<rmdir> only. This is a composite request that
1080	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1230	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1081	everything else.	1231	everything else.
1082		1232
1083	=cut	1233	=cut
1084		1234
…		…
1105	add $grp $dirgrp;	1255	add $grp $dirgrp;
1106	};	1256	};
1107		1257
1108	$grp	1258	$grp
1109	}	1259	}
		1260
		1261	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1262
		1263	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1264
		1265	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1266	they execute asynchronously and pass the return value to the callback.
		1267
		1268	Both calls can be used for a lot of things, some of which make more sense
		1269	to run asynchronously in their own thread, while some others make less
		1270	sense. For example, calls that block waiting for external events, such
		1271	as locking, will also lock down an I/O thread while it is waiting, which
		1272	can deadlock the whole I/O system. At the same time, there might be no
		1273	alternative to using a thread to wait.
		1274
		1275	So in general, you should only use these calls for things that do
		1276	(filesystem) I/O, not for things that wait for other events (network,
		1277	other processes), although if you are careful and know what you are doing,
		1278	you still can.
		1279
		1280	The following constants are available (missing ones are, as usual C<0>):
		1281
		1282	C<F_DUPFD_CLOEXEC>,
		1283
		1284	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1285
		1286	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1287
		1288	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1289	C<FS_IOC_FIEMAP>.
		1290
		1291	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1292	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1293
		1294	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1295	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1296	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1297	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1298	C<FS_FL_USER_MODIFIABLE>.
		1299
		1300	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1301	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1302	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1303	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1110		1304
1111	=item aio_sync $callback->($status)	1305	=item aio_sync $callback->($status)
1112		1306
1113	Asynchronously call sync and call the callback when finished.	1307	Asynchronously call sync and call the callback when finished.
1114		1308
…		…
1183	};	1377	};
1184		1378
1185	$grp	1379	$grp
1186	}	1380	}
1187		1381
1188	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1382	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1189		1383
1190	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1384	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1191	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1385	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1192	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1386	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1193	scalar must only be modified in-place while an aio operation is pending on	1387	scalar must only be modified in-place while an aio operation is pending on
…		…
1195		1389
1196	It calls the C<msync> function of your OS, if available, with the memory	1390	It calls the C<msync> function of your OS, if available, with the memory
1197	area starting at C<$offset> in the string and ending C<$length> bytes	1391	area starting at C<$offset> in the string and ending C<$length> bytes
1198	later. If C<$length> is negative, counts from the end, and if C<$length>	1392	later. If C<$length> is negative, counts from the end, and if C<$length>
1199	is C<undef>, then it goes till the end of the string. The flags can be	1393	is C<undef>, then it goes till the end of the string. The flags can be
1200	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1394	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1201	C<IO::AIO::MS_SYNC>.	1395	C<IO::AIO::MS_INVALIDATE>.
1202		1396
1203	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1397	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1204		1398
1205	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1399	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1206	scalars.	1400	scalars.
1207		1401
1208	It touches (reads or writes) all memory pages in the specified	1402	It touches (reads or writes) all memory pages in the specified
1209	range inside the scalar. All caveats and parameters are the same	1403	range inside the scalar. All caveats and parameters are the same
1210	as for C<aio_msync>, above, except for flags, which must be either	1404	as for C<aio_msync>, above, except for flags, which must be either
1211	C<0> (which reads all pages and ensures they are instantiated) or	1405	C<0> (which reads all pages and ensures they are instantiated) or
1212	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1406	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1213	writing an octet from it, which dirties the page).	1407	writing an octet from it, which dirties the page).
1214		1408
1215	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1409	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1216		1410
1217	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1411	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1251		1445
1252	aio_mlockall IO::AIO::MCL_FUTURE;	1446	aio_mlockall IO::AIO::MCL_FUTURE;
1253		1447
1254	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)	1448	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1255		1449
1256	Queries the extents of the given file (by calling the Linux FIEMAP ioctl,	1450	Queries the extents of the given file (by calling the Linux C<FIEMAP>
1257	see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the	1451	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1258	C<ioctl> is not available on your OS, then this rquiest will fail with	1452	the ioctl is not available on your OS, then this request will fail with
1259	C<ENOSYS>.	1453	C<ENOSYS>.
1260		1454
1261	C<$start> is the starting offset to query extents for, C<$length> is the	1455	C<$start> is the starting offset to query extents for, C<$length> is the
1262	size of the range to query - if it is C<undef>, then the whole file will	1456	size of the range to query - if it is C<undef>, then the whole file will
1263	be queried.	1457	be queried.
…		…
1266	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also	1460	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1267	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query	1461	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1268	the data portion.	1462	the data portion.
1269		1463
1270	C<$count> is the maximum number of extent records to return. If it is	1464	C<$count> is the maximum number of extent records to return. If it is
1271	C<undef>, then IO::AIO queries all extents of the file. As a very special	1465	C<undef>, then IO::AIO queries all extents of the range. As a very special
1272	case, if it is C<0>, then the callback receives the number of extents	1466	case, if it is C<0>, then the callback receives the number of extents
1273	instead of the extents themselves.	1467	instead of the extents themselves (which is unreliable, see below).
1274		1468
1275	If an error occurs, the callback receives no arguments. The special	1469	If an error occurs, the callback receives no arguments. The special
1276	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.	1470	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1277		1471
1278	Otherwise, the callback receives an array reference with extent	1472	Otherwise, the callback receives an array reference with extent
…		…
1280	following members:	1474	following members:
1281		1475
1282	[$logical, $physical, $length, $flags]	1476	[$logical, $physical, $length, $flags]
1283		1477
1284	Flags is any combination of the following flag values (typically either C<0>	1478	Flags is any combination of the following flag values (typically either C<0>
1285	or C<IO::AIO::FIEMAP_EXTENT_LAST>):	1479	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1286		1480
1287	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,	1481	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1288	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,	1482	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1289	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,	1483	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1290	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,	1484	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1291	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or	1485	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1292	C<IO::AIO::FIEMAP_EXTENT_SHARED>.	1486	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1293		1487
		1488	At the time of this writing (Linux 3.2), this request is unreliable unless
		1489	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1490	it to return all extents of a range for files with a large number of
		1491	extents. The code (only) works around all these issues if C<$count> is
		1492	C<undef>.
		1493
1294	=item aio_group $callback->(...)	1494	=item aio_group $callback->(...)
1295		1495
1296	This is a very special aio request: Instead of doing something, it is a	1496	This is a very special aio request: Instead of doing something, it is a
1297	container for other aio requests, which is useful if you want to bundle	1497	container for other aio requests, which is useful if you want to bundle
1298	many requests into a single, composite, request with a definite callback	1498	many requests into a single, composite, request with a definite callback
…		…
1381	aio_stat [$etcdir, "passwd"], sub {	1581	aio_stat [$etcdir, "passwd"], sub {
1382	# yay	1582	# yay
1383	};	1583	};
1384	};	1584	};
1385		1585
1386	That C<aio_wd> is a request and not a normal function shows that creating	1586	The fact that C<aio_wd> is a request and not a normal function shows that
1387	an IO::AIO::WD object is itself a potentially blocking operation, which is	1587	creating an IO::AIO::WD object is itself a potentially blocking operation,
1388	why it is done asynchronously.	1588	which is why it is done asynchronously.
1389		1589
1390	To stat the directory obtained with C<aio_wd> above, one could write	1590	To stat the directory obtained with C<aio_wd> above, one could write
1391	either of the following three request calls:	1591	either of the following three request calls:
1392		1592
1393	aio_lstat "/etc" , sub { ... # pathname as normal string	1593	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1410	There are some caveats: when directories get renamed (or deleted), the	1610	There are some caveats: when directories get renamed (or deleted), the
1411	pathname string doesn't change, so will point to the new directory (or	1611	pathname string doesn't change, so will point to the new directory (or
1412	nowhere at all), while the directory fd, if available on the system,	1612	nowhere at all), while the directory fd, if available on the system,
1413	will still point to the original directory. Most functions accepting a	1613	will still point to the original directory. Most functions accepting a
1414	pathname will use the directory fd on newer systems, and the string on	1614	pathname will use the directory fd on newer systems, and the string on
1415	older systems. Some functions (such as realpath) will always rely on the	1615	older systems. Some functions (such as C<aio_realpath>) will always rely on
1416	string form of the pathname.	1616	the string form of the pathname.
1417		1617
1418	So this fucntionality is mainly useful to get some protection against	1618	So this functionality is mainly useful to get some protection against
1419	C<chdir>, to easily get an absolute path out of a relative path for future	1619	C<chdir>, to easily get an absolute path out of a relative path for future
1420	reference, and to speed up doing many operations in the same directory	1620	reference, and to speed up doing many operations in the same directory
1421	(e.g. when stat'ing all files in a directory).	1621	(e.g. when stat'ing all files in a directory).
1422		1622
1423	The following functions implement this working directory abstraction:	1623	The following functions implement this working directory abstraction:
…		…
1436	passing C<undef> as working directory component of a pathname fails the	1636	passing C<undef> as working directory component of a pathname fails the
1437	request with C<ENOENT>, there is often no need for error checking in the	1637	request with C<ENOENT>, there is often no need for error checking in the
1438	C<aio_wd> callback, as future requests using the value will fail in the	1638	C<aio_wd> callback, as future requests using the value will fail in the
1439	expected way.	1639	expected way.
1440		1640
1441	If this call isn't available because your OS lacks it or it couldn't be
1442	detected, it will be emulated by calling C<fsync> instead.
1443
1444	=item IO::AIO::CWD	1641	=item IO::AIO::CWD
1445		1642
1446	This is a compiletime constant (object) that represents the process	1643	This is a compiletime constant (object) that represents the process
1447	current working directory.	1644	current working directory.
1448		1645
1449	Specifying this object as working directory object for a pathname is as	1646	Specifying this object as working directory object for a pathname is as if
1450	if the pathname would be specified directly, without a directory object,	1647	the pathname would be specified directly, without a directory object. For
1451	e.g., these calls are functionally identical:	1648	example, these calls are functionally identical:
1452		1649
1453	aio_stat "somefile", sub { ... };	1650	aio_stat "somefile", sub { ... };
1454	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1651	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1455		1652
1456	=back	1653	=back
1457		1654
		1655	To recover the path associated with an IO::AIO::WD object, you can use
		1656	C<aio_realpath>:
		1657
		1658	aio_realpath $wd, sub {
		1659	warn "path is $_[0]\n";
		1660	};
		1661
		1662	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1663	sometimes, fall back to using an absolue path.
1458		1664
1459	=head2 IO::AIO::REQ CLASS	1665	=head2 IO::AIO::REQ CLASS
1460		1666
1461	All non-aggregate C<aio_*> functions return an object of this class when	1667	All non-aggregate C<aio_*> functions return an object of this class when
1462	called in non-void context.	1668	called in non-void context.
…		…
1640		1846
1641	See C<poll_cb> for an example.	1847	See C<poll_cb> for an example.
1642		1848
1643	=item IO::AIO::poll_cb	1849	=item IO::AIO::poll_cb
1644		1850
1645	Process some outstanding events on the result pipe. You have to call	1851	Process some requests that have reached the result phase (i.e. they have
		1852	been executed but the results are not yet reported). You have to call
		1853	this "regularly" to finish outstanding requests.
		1854
1646	this regularly. Returns C<0> if all events could be processed (or there	1855	Returns C<0> if all events could be processed (or there were no
1647	were no events to process), or C<-1> if it returned earlier for whatever	1856	events to process), or C<-1> if it returned earlier for whatever
1648	reason. Returns immediately when no events are outstanding. The amount of	1857	reason. Returns immediately when no events are outstanding. The amount
1649	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1858	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1650	C<IO::AIO::max_poll_time>.	1859	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1651		1860
1652	If not all requests were processed for whatever reason, the filehandle	1861	If not all requests were processed for whatever reason, the poll file
1653	will still be ready when C<poll_cb> returns, so normally you don't have to	1862	descriptor will still be ready when C<poll_cb> returns, so normally you
1654	do anything special to have it called later.	1863	don't have to do anything special to have it called later.
1655		1864
1656	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1865	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1657	ready, it can be beneficial to call this function from loops which submit	1866	ready, it can be beneficial to call this function from loops which submit
1658	a lot of requests, to make sure the results get processed when they become	1867	a lot of requests, to make sure the results get processed when they become
1659	available and not just when the loop is finished and the event loop takes	1868	available and not just when the loop is finished and the event loop takes
…		…
1668	poll => 'r', async => 1,	1877	poll => 'r', async => 1,
1669	cb => \&IO::AIO::poll_cb);	1878	cb => \&IO::AIO::poll_cb);
1670		1879
1671	=item IO::AIO::poll_wait	1880	=item IO::AIO::poll_wait
1672		1881
1673	If there are any outstanding requests and none of them in the result	1882	Wait until either at least one request is in the result phase or no
1674	phase, wait till the result filehandle becomes ready for reading (simply	1883	requests are outstanding anymore.
1675	does a C<select> on the filehandle. This is useful if you want to	1884
1676	synchronously wait for some requests to finish).	1885	This is useful if you want to synchronously wait for some requests to
		1886	become ready, without actually handling them.
1677		1887
1678	See C<nreqs> for an example.	1888	See C<nreqs> for an example.
1679		1889
1680	=item IO::AIO::poll	1890	=item IO::AIO::poll
1681		1891
…		…
1802		2012
1803	This is a very bad function to use in interactive programs because it	2013	This is a very bad function to use in interactive programs because it
1804	blocks, and a bad way to reduce concurrency because it is inexact: Better	2014	blocks, and a bad way to reduce concurrency because it is inexact: Better
1805	use an C<aio_group> together with a feed callback.	2015	use an C<aio_group> together with a feed callback.
1806		2016
1807	It's main use is in scripts without an event loop - when you want to stat	2017	Its main use is in scripts without an event loop - when you want to stat
1808	a lot of files, you can write somehting like this:	2018	a lot of files, you can write something like this:
1809		2019
1810	IO::AIO::max_outstanding 32;	2020	IO::AIO::max_outstanding 32;
1811		2021
1812	for my $path (...) {	2022	for my $path (...) {
1813	aio_stat $path , ...;	2023	aio_stat $path , ...;
…		…
1852		2062
1853	=back	2063	=back
1854		2064
1855	=head3 MISCELLANEOUS FUNCTIONS	2065	=head3 MISCELLANEOUS FUNCTIONS
1856		2066
1857	IO::AIO implements some functions that might be useful, but are not	2067	IO::AIO implements some functions that are useful when you want to use
1858	asynchronous.	2068	some "Advanced I/O" function not available to in Perl, without going the
		2069	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2070	counterpart.
1859		2071
1860	=over 4	2072	=over 4
		2073
		2074	=item $numfd = IO::AIO::get_fdlimit
		2075
		2076	This function is I<EXPERIMENTAL> and subject to change.
		2077
		2078	Tries to find the current file descriptor limit and returns it, or
		2079	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2080	the highest valid file descriptor number.
		2081
		2082	=item IO::AIO::min_fdlimit [$numfd]
		2083
		2084	This function is I<EXPERIMENTAL> and subject to change.
		2085
		2086	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2087	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2088	is missing, it will try to set a very high limit, although this is not
		2089	recommended when you know the actual minimum that you require.
		2090
		2091	If the limit cannot be raised enough, the function makes a best-effort
		2092	attempt to increase the limit as much as possible, using various
		2093	tricks, while still failing. You can query the resulting limit using
		2094	C<IO::AIO::get_fdlimit>.
		2095
		2096	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2097	true.
1861		2098
1862	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2099	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1863		2100
1864	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2101	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1865	but is blocking (this makes most sense if you know the input data is	2102	but is blocking (this makes most sense if you know the input data is
…		…
1882	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2119	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1883		2120
1884	Simply calls the C<posix_madvise> function (see its	2121	Simply calls the C<posix_madvise> function (see its
1885	manpage for details). The following advice constants are	2122	manpage for details). The following advice constants are
1886	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2123	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1887	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2124	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2125	C<IO::AIO::MADV_DONTNEED>.
		2126
		2127	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2128	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2129	will be reduced to fit into the C<$scalar>.
1888		2130
1889	On systems that do not implement C<posix_madvise>, this function returns	2131	On systems that do not implement C<posix_madvise>, this function returns
1890	ENOSYS, otherwise the return value of C<posix_madvise>.	2132	ENOSYS, otherwise the return value of C<posix_madvise>.
1891		2133
1892	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2134	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1894	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2136	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1895	$scalar (see its manpage for details). The following protect	2137	$scalar (see its manpage for details). The following protect
1896	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2138	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1897	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2139	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1898		2140
		2141	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2142	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2143	will be reduced to fit into the C<$scalar>.
		2144
1899	On systems that do not implement C<mprotect>, this function returns	2145	On systems that do not implement C<mprotect>, this function returns
1900	ENOSYS, otherwise the return value of C<mprotect>.	2146	ENOSYS, otherwise the return value of C<mprotect>.
1901		2147
1902	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2148	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1903		2149
1904	Memory-maps a file (or anonymous memory range) and attaches it to the	2150	Memory-maps a file (or anonymous memory range) and attaches it to the
1905	given C<$scalar>, which will act like a string scalar.	2151	given C<$scalar>, which will act like a string scalar. Returns true on
		2152	success, and false otherwise.
1906		2153
		2154	The scalar must exist, but its contents do not matter - this means you
		2155	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2156	the scalar first.
		2157
1907	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2158	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1908	change the string length, and most read-only operations such as copying it	2159	which don't change the string length, and most read-only operations such
1909	or searching it with regexes and so on.	2160	as copying it or searching it with regexes and so on.
1910		2161
1911	Anything else is unsafe and will, at best, result in memory leaks.	2162	Anything else is unsafe and will, at best, result in memory leaks.
1912		2163
1913	The memory map associated with the C<$scalar> is automatically removed	2164	The memory map associated with the C<$scalar> is automatically removed
1914	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2165	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1915	C<IO::AIO::munmap> functions are called.	2166	or C<IO::AIO::munmap> functions are called on it.
1916		2167
1917	This calls the C<mmap>(2) function internally. See your system's manual	2168	This calls the C<mmap>(2) function internally. See your system's manual
1918	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2169	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1919		2170
1920	The C<$length> must be larger than zero and smaller than the actual	2171	The C<$length> must be larger than zero and smaller than the actual
1921	filesize.	2172	filesize.
1922		2173
1923	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2174	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1924	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2175	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1925		2176
1926	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2177	C<$flags> can be a combination of
1927	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2178	C<IO::AIO::MAP_SHARED> or
1928	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2179	C<IO::AIO::MAP_PRIVATE>,
		2180	or a number of system-specific flags (when not available, the are C<0>):
1929	(which is set to C<MAP_ANON> if your system only provides this	2181	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1930	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2182	C<IO::AIO::MAP_LOCKED>,
1931	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2183	C<IO::AIO::MAP_NORESERVE>,
		2184	C<IO::AIO::MAP_POPULATE>,
1932	C<IO::AIO::MAP_NONBLOCK>	2185	C<IO::AIO::MAP_NONBLOCK>,
		2186	C<IO::AIO::MAP_FIXED>,
		2187	C<IO::AIO::MAP_GROWSDOWN>,
		2188	C<IO::AIO::MAP_32BIT>,
		2189	C<IO::AIO::MAP_HUGETLB> or
		2190	C<IO::AIO::MAP_STACK>.
1933		2191
1934	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2192	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1935		2193
1936	C<$offset> is the offset from the start of the file - it generally must be	2194	C<$offset> is the offset from the start of the file - it generally must be
1937	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2195	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1962		2220
1963	Calls the C<munlockall> function.	2221	Calls the C<munlockall> function.
1964		2222
1965	On systems that do not implement C<munlockall>, this function returns	2223	On systems that do not implement C<munlockall>, this function returns
1966	ENOSYS, otherwise the return value of C<munlockall>.	2224	ENOSYS, otherwise the return value of C<munlockall>.
		2225
		2226	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2227
		2228	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2229	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2230	should be the file offset.
		2231
		2232	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2233	silently corrupt the data in this case.
		2234
		2235	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2236	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2237	C<IO::AIO::SPLICE_F_GIFT>.
		2238
		2239	See the C<splice(2)> manpage for details.
		2240
		2241	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2242
		2243	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2244	description for C<IO::AIO::splice> above for details.
		2245
		2246	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2247
		2248	Attempts to query or change the pipe buffer size. Obviously works only
		2249	on pipes, and currently works only on GNU/Linux systems, and fails with
		2250	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2251	size on other systems, drop me a note.
		2252
		2253	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2254
		2255	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2256	C<$flags> is missing or C<0>, then this should be the same as a call to
		2257	perl's built-in C<pipe> function and create a new pipe, and works on
		2258	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2259	(..., 4096, O_BINARY)>.
		2260
		2261	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2262	the given flags (Linux 2.6.27, glibc 2.9).
		2263
		2264	On success, the read and write file handles are returned.
		2265
		2266	On error, nothing will be returned. If the pipe2 syscall is missing and
		2267	C<$flags> is non-zero, fails with C<ENOSYS>.
		2268
		2269	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2270	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2271	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1967		2272
1968	=back	2273	=back
1969		2274
1970	=cut	2275	=cut
1971		2276

Diff Legend

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

Comparing IO-AIO/AIO.pm (file contents): Revision 1.223 by root, Fri Apr 6 22:51:02 2012 UTC vs. Revision 1.278 by root, Sun Oct 1 07:24:34 2017 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.223 by root, Fri Apr 6 22:51:02 2012 UTC vs.
Revision 1.278 by root, Sun Oct 1 07:24:34 2017 UTC