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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs.
Revision 1.259 by root, Tue Feb 23 19:42:43 2016 UTC

…		…
68	=head2 EXAMPLE	68	=head2 EXAMPLE
69		69
70	This is a simple example that uses the EV module and loads	70	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
72		72
73	use Fcntl;
74	use EV;	73	use EV;
75	use IO::AIO;	74	use IO::AIO;
76		75
77	# register the IO::AIO callback with EV	76	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	77	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		94
96	# file contents now in $contents	95	# file contents now in $contents
97	print $contents;	96	print $contents;
98		97
99	# exit event loop and program	98	# exit event loop and program
100	EV::unloop;	99	EV::break;
101	};	100	};
102	};	101	};
103		102
104	# possibly queue up other requests, or open GUI windows,	103	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	104	# check for sockets etc. etc.
106		105
107	# process events as long as there are some:	106	# process events as long as there are some:
108	EV::loop;	107	EV::run;
109		108
110	=head1 REQUEST ANATOMY AND LIFETIME	109	=head1 REQUEST ANATOMY AND LIFETIME
111		110
112	Every C<aio_*> function creates a request. which is a C data structure not	111	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	112	directly visible to Perl.
…		…
168	use common::sense;	167	use common::sense;
169		168
170	use base 'Exporter';	169	use base 'Exporter';
171		170
172	BEGIN {	171	BEGIN {
173	our $VERSION = '4.0';	172	our $VERSION = 4.33;
174		173
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	174	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	175	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync	176	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	177	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179	aio_pathsync aio_readahead	178	aio_pathsync aio_readahead aio_fiemap aio_allocate
180	aio_rename aio_link aio_move aio_copy aio_group	179	aio_rename aio_link aio_move aio_copy aio_group
181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182	aio_chmod aio_utime aio_truncate	181	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	182	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs	183	aio_statvfs
…		…
202		201
203	=head1 FUNCTIONS	202	=head1 FUNCTIONS
204		203
205	=head2 QUICK OVERVIEW	204	=head2 QUICK OVERVIEW
206		205
207	This section simply lists the prototypes of the most important functions	206	This section simply lists the prototypes most of the functions for
208	for quick reference. See the following sections for function-by-function	207	quick reference. See the following sections for function-by-function
209	documentation.	208	documentation.
210		209
211	aio_wd $pathname, $callback->($wd)	210	aio_wd $pathname, $callback->($wd)
212	aio_open $pathname, $flags, $mode, $callback->($fh)	211	aio_open $pathname, $flags, $mode, $callback->($fh)
213	aio_close $fh, $callback->($status)	212	aio_close $fh, $callback->($status)
		213	aio_seek $fh,$offset,$whence, $callback->($offs)
214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217	aio_readahead $fh,$offset,$length, $callback->($retval)	217	aio_readahead $fh,$offset,$length, $callback->($retval)
218	aio_stat $fh_or_path, $callback->($status)	218	aio_stat $fh_or_path, $callback->($status)
219	aio_lstat $fh, $callback->($status)	219	aio_lstat $fh, $callback->($status)
220	aio_statvfs $fh_or_path, $callback->($statvfs)	220	aio_statvfs $fh_or_path, $callback->($statvfs)
221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		223	aio_chmod $fh_or_path, $mode, $callback->($status)
223	aio_truncate $fh_or_path, $offset, $callback->($status)	224	aio_truncate $fh_or_path, $offset, $callback->($status)
224	aio_chmod $fh_or_path, $mode, $callback->($status)	225	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		226	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225	aio_unlink $pathname, $callback->($status)	227	aio_unlink $pathname, $callback->($status)
226	aio_mknod $path, $mode, $dev, $callback->($status)	228	aio_mknod $pathname, $mode, $dev, $callback->($status)
227	aio_link $srcpath, $dstpath, $callback->($status)	229	aio_link $srcpath, $dstpath, $callback->($status)
228	aio_symlink $srcpath, $dstpath, $callback->($status)	230	aio_symlink $srcpath, $dstpath, $callback->($status)
229	aio_readlink $path, $callback->($link)	231	aio_readlink $pathname, $callback->($link)
230	aio_realpath $path, $callback->($link)	232	aio_realpath $pathname, $callback->($path)
231	aio_rename $srcpath, $dstpath, $callback->($status)	233	aio_rename $srcpath, $dstpath, $callback->($status)
232	aio_mkdir $pathname, $mode, $callback->($status)	234	aio_mkdir $pathname, $mode, $callback->($status)
233	aio_rmdir $pathname, $callback->($status)	235	aio_rmdir $pathname, $callback->($status)
234	aio_readdir $pathname, $callback->($entries)	236	aio_readdir $pathname, $callback->($entries)
235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	239	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		240	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238	aio_load $path, $data, $callback->($status)	241	aio_load $pathname, $data, $callback->($status)
239	aio_copy $srcpath, $dstpath, $callback->($status)	242	aio_copy $srcpath, $dstpath, $callback->($status)
240	aio_move $srcpath, $dstpath, $callback->($status)	243	aio_move $srcpath, $dstpath, $callback->($status)
241	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
242	aio_rmtree $path, $callback->($status)	244	aio_rmtree $pathname, $callback->($status)
		245	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		246	aio_ioctl $fh, $request, $buf, $callback->($status)
243	aio_sync $callback->($status)	247	aio_sync $callback->($status)
244	aio_syncfs $fh, $callback->($status)	248	aio_syncfs $fh, $callback->($status)
245	aio_fsync $fh, $callback->($status)	249	aio_fsync $fh, $callback->($status)
246	aio_fdatasync $fh, $callback->($status)	250	aio_fdatasync $fh, $callback->($status)
247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	251	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248	aio_pathsync $path, $callback->($status)	252	aio_pathsync $pathname, $callback->($status)
249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	253	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	254	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	255	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252	aio_mlockall $flags, $callback->($status)	256	aio_mlockall $flags, $callback->($status)
253	aio_group $callback->(...)	257	aio_group $callback->(...)
…		…
271	IO::AIO::nready	275	IO::AIO::nready
272	IO::AIO::npending	276	IO::AIO::npending
273		277
274	IO::AIO::sendfile $ofh, $ifh, $offset, $count	278	IO::AIO::sendfile $ofh, $ifh, $offset, $count
275	IO::AIO::fadvise $fh, $offset, $len, $advice	279	IO::AIO::fadvise $fh, $offset, $len, $advice
		280	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		281	IO::AIO::munmap $scalar
276	IO::AIO::madvise $scalar, $offset, $length, $advice	282	IO::AIO::madvise $scalar, $offset, $length, $advice
277	IO::AIO::mprotect $scalar, $offset, $length, $protect	283	IO::AIO::mprotect $scalar, $offset, $length, $protect
278	IO::AIO::munlock $scalar, $offset = 0, $length = undef	284	IO::AIO::munlock $scalar, $offset = 0, $length = undef
279	IO::AIO::munlockall	285	IO::AIO::munlockall
280		286
281	=head2 AIO REQUEST FUNCTIONS	287	=head2 API NOTES
282		288
283	All the C<aio_*> calls are more or less thin wrappers around the syscall	289	All the C<aio_*> calls are more or less thin wrappers around the syscall
284	with the same name (sans C<aio_>). The arguments are similar or identical,	290	with the same name (sans C<aio_>). The arguments are similar or identical,
285	and they all accept an additional (and optional) C<$callback> argument	291	and they all accept an additional (and optional) C<$callback> argument
286	which must be a code reference. This code reference will get called with	292	which must be a code reference. This code reference will be called after
287	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	293	the syscall has been executed in an asynchronous fashion. The results
288	perl, which usually delivers "false") as its sole argument after the given	294	of the request will be passed as arguments to the callback (and, if an
289	syscall has been executed asynchronously.	295	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		296	most syscalls return C<-1> on error, unlike perl, which usually delivers
		297	"false").
		298
		299	Some requests (such as C<aio_readdir>) pass the actual results and
		300	communicate failures by passing C<undef>.
290		301
291	All functions expecting a filehandle keep a copy of the filehandle	302	All functions expecting a filehandle keep a copy of the filehandle
292	internally until the request has finished.	303	internally until the request has finished.
293		304
294	All functions return request objects of type L<IO::AIO::REQ> that allow	305	All functions return request objects of type L<IO::AIO::REQ> that allow
295	further manipulation of those requests while they are in-flight.	306	further manipulation of those requests while they are in-flight.
296		307
297	The pathnames you pass to these routines I<must> be absolute and	308	The pathnames you pass to these routines I<should> be absolute. The
298	encoded as octets. The reason for the former is that at the time the	309	reason for this is that at the time the request is being executed, the
299	request is being executed, the current working directory could have	310	current working directory could have changed. Alternatively, you can
300	changed. Alternatively, you can make sure that you never change the	311	make sure that you never change the current working directory anywhere
301	current working directory anywhere in the program and then use relative	312	in the program and then use relative paths. You can also take advantage
302	paths.	313	of IO::AIOs working directory abstraction, that lets you specify paths
		314	relative to some previously-opened "working directory object" - see the
		315	description of the C<IO::AIO::WD> class later in this document.
303		316
304	To encode pathnames as octets, either make sure you either: a) always pass	317	To encode pathnames as octets, either make sure you either: a) always pass
305	in filenames you got from outside (command line, readdir etc.) without	318	in filenames you got from outside (command line, readdir etc.) without
306	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	319	tinkering, b) are in your native filesystem encoding, c) use the Encode
307	your pathnames to the locale (or other) encoding in effect in the user	320	module and encode your pathnames to the locale (or other) encoding in
308	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	321	effect in the user environment, d) use Glib::filename_from_unicode on
309	use something else to ensure your scalar has the correct contents.	322	unicode filenames or e) use something else to ensure your scalar has the
		323	correct contents.
310		324
311	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	325	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
312	handles correctly whether it is set or not.	326	handles correctly whether it is set or not.
		327
		328	=head2 AIO REQUEST FUNCTIONS
313		329
314	=over 4	330	=over 4
315		331
316	=item $prev_pri = aioreq_pri [$pri]	332	=item $prev_pri = aioreq_pri [$pri]
317		333
…		…
347		363
348		364
349	=item aio_open $pathname, $flags, $mode, $callback->($fh)	365	=item aio_open $pathname, $flags, $mode, $callback->($fh)
350		366
351	Asynchronously open or create a file and call the callback with a newly	367	Asynchronously open or create a file and call the callback with a newly
352	created filehandle for the file.	368	created filehandle for the file (or C<undef> in case of an error).
353		369
354	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	370	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
355	for an explanation.	371	for an explanation.
356		372
357	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	373	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
380	following POSIX and non-POSIX constants are available (missing ones on	396	following POSIX and non-POSIX constants are available (missing ones on
381	your system are, as usual, C<0>):	397	your system are, as usual, C<0>):
382		398
383	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	399	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
384	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	400	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
385	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	401	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
386		402
387		403
388	=item aio_close $fh, $callback->($status)	404	=item aio_close $fh, $callback->($status)
389		405
390	Asynchronously close a file and call the callback with the result	406	Asynchronously close a file and call the callback with the result
…		…
399		415
400	Or in other words: the file descriptor will be closed, but it will not be	416	Or in other words: the file descriptor will be closed, but it will not be
401	free for reuse until the perl filehandle is closed.	417	free for reuse until the perl filehandle is closed.
402		418
403	=cut	419	=cut
		420
		421	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		422
		423	Seeks the filehandle to the new C<$offset>, similarly to perl's
		424	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		425	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		426	C<IO::AIO::SEEK_END>).
		427
		428	The resulting absolute offset will be passed to the callback, or C<-1> in
		429	case of an error.
		430
		431	In theory, the C<$whence> constants could be different than the
		432	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		433	so don't panic.
		434
		435	As a GNU/Linux (and maybe Solaris) extension, also the constants
		436	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		437	could be found. No guarantees about suitability for use in C<aio_seek> or
		438	Perl's C<sysseek> can be made though, although I would naively assume they
		439	"just work".
404		440
405	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	441	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
406		442
407	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	443	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
408		444
…		…
568	namemax => 255,	604	namemax => 255,
569	frsize => 1024,	605	frsize => 1024,
570	fsid => 1810	606	fsid => 1810
571	}	607	}
572		608
		609	Here is a (likely partial - send me updates!) list of fsid values used by
		610	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		611
		612	0x0000adf5 adfs
		613	0x0000adff affs
		614	0x5346414f afs
		615	0x09041934 anon-inode filesystem
		616	0x00000187 autofs
		617	0x42465331 befs
		618	0x1badface bfs
		619	0x42494e4d binfmt_misc
		620	0x9123683e btrfs
		621	0x0027e0eb cgroupfs
		622	0xff534d42 cifs
		623	0x73757245 coda
		624	0x012ff7b7 coh
		625	0x28cd3d45 cramfs
		626	0x453dcd28 cramfs-wend (wrong endianness)
		627	0x64626720 debugfs
		628	0x00001373 devfs
		629	0x00001cd1 devpts
		630	0x0000f15f ecryptfs
		631	0x00414a53 efs
		632	0x0000137d ext
		633	0x0000ef53 ext2/ext3/ext4
		634	0x0000ef51 ext2
		635	0xf2f52010 f2fs
		636	0x00004006 fat
		637	0x65735546 fuseblk
		638	0x65735543 fusectl
		639	0x0bad1dea futexfs
		640	0x01161970 gfs2
		641	0x47504653 gpfs
		642	0x00004244 hfs
		643	0xf995e849 hpfs
		644	0x00c0ffee hostfs
		645	0x958458f6 hugetlbfs
		646	0x2bad1dea inotifyfs
		647	0x00009660 isofs
		648	0x000072b6 jffs2
		649	0x3153464a jfs
		650	0x6b414653 k-afs
		651	0x0bd00bd0 lustre
		652	0x0000137f minix
		653	0x0000138f minix 30 char names
		654	0x00002468 minix v2
		655	0x00002478 minix v2 30 char names
		656	0x00004d5a minix v3
		657	0x19800202 mqueue
		658	0x00004d44 msdos
		659	0x0000564c novell
		660	0x00006969 nfs
		661	0x6e667364 nfsd
		662	0x00003434 nilfs
		663	0x5346544e ntfs
		664	0x00009fa1 openprom
		665	0x7461636F ocfs2
		666	0x00009fa0 proc
		667	0x6165676c pstorefs
		668	0x0000002f qnx4
		669	0x68191122 qnx6
		670	0x858458f6 ramfs
		671	0x52654973 reiserfs
		672	0x00007275 romfs
		673	0x67596969 rpc_pipefs
		674	0x73636673 securityfs
		675	0xf97cff8c selinux
		676	0x0000517b smb
		677	0x534f434b sockfs
		678	0x73717368 squashfs
		679	0x62656572 sysfs
		680	0x012ff7b6 sysv2
		681	0x012ff7b5 sysv4
		682	0x01021994 tmpfs
		683	0x15013346 udf
		684	0x00011954 ufs
		685	0x54190100 ufs byteswapped
		686	0x00009fa2 usbdevfs
		687	0x01021997 v9fs
		688	0xa501fcf5 vxfs
		689	0xabba1974 xenfs
		690	0x012ff7b4 xenix
		691	0x58465342 xfs
		692	0x012fd16d xia
573		693
574	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	694	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
575		695
576	Works like perl's C<utime> function (including the special case of $atime	696	Works like perl's C<utime> function (including the special case of $atime
577	and $mtime being undef). Fractional times are supported if the underlying	697	and $mtime being undef). Fractional times are supported if the underlying
…		…
605	=item aio_truncate $fh_or_path, $offset, $callback->($status)	725	=item aio_truncate $fh_or_path, $offset, $callback->($status)
606		726
607	Works like truncate(2) or ftruncate(2).	727	Works like truncate(2) or ftruncate(2).
608		728
609		729
		730	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		731
		732	Allocates or frees disk space according to the C<$mode> argument. See the
		733	linux C<fallocate> documentation for details.
		734
		735	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		736	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		737	to deallocate a file range.
		738
		739	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		740	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		741	your L<fallocate(2)> manpage).
		742
		743	The file system block size used by C<fallocate> is presumably the
		744	C<f_bsize> returned by C<statvfs>.
		745
		746	If C<fallocate> isn't available or cannot be emulated (currently no
		747	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		748
		749
610	=item aio_chmod $fh_or_path, $mode, $callback->($status)	750	=item aio_chmod $fh_or_path, $mode, $callback->($status)
611		751
612	Works like perl's C<chmod> function.	752	Works like perl's C<chmod> function.
613		753
614		754
…		…
616		756
617	Asynchronously unlink (delete) a file and call the callback with the	757	Asynchronously unlink (delete) a file and call the callback with the
618	result code.	758	result code.
619		759
620		760
621	=item aio_mknod $path, $mode, $dev, $callback->($status)	761	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
622		762
623	[EXPERIMENTAL]	763	[EXPERIMENTAL]
624		764
625	Asynchronously create a device node (or fifo). See mknod(2).	765	Asynchronously create a device node (or fifo). See mknod(2).
626		766
627	The only (POSIX-) portable way of calling this function is:	767	The only (POSIX-) portable way of calling this function is:
628		768
629	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	769	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
630		770
631	See C<aio_stat> for info about some potentially helpful extra constants	771	See C<aio_stat> for info about some potentially helpful extra constants
632	and functions.	772	and functions.
633		773
634	=item aio_link $srcpath, $dstpath, $callback->($status)	774	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
641		781
642	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	782	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
643	the path C<$dstpath> and call the callback with the result code.	783	the path C<$dstpath> and call the callback with the result code.
644		784
645		785
646	=item aio_readlink $path, $callback->($link)	786	=item aio_readlink $pathname, $callback->($link)
647		787
648	Asynchronously read the symlink specified by C<$path> and pass it to	788	Asynchronously read the symlink specified by C<$path> and pass it to
649	the callback. If an error occurs, nothing or undef gets passed to the	789	the callback. If an error occurs, nothing or undef gets passed to the
650	callback.	790	callback.
651		791
652		792
653	=item aio_realpath $path, $callback->($path)	793	=item aio_realpath $pathname, $callback->($path)
654		794
655	Asynchronously make the path absolute and resolve any symlinks in	795	Asynchronously make the path absolute and resolve any symlinks in
656	C<$path>. The resulting path only consists of directories (Same as	796	C<$path>. The resulting path only consists of directories (same as
657	L<Cwd::realpath>).	797	L<Cwd::realpath>).
658		798
659	This request can be used to get the absolute path of the current working	799	This request can be used to get the absolute path of the current working
660	directory by passing it a path of F<.> (a single dot).	800	directory by passing it a path of F<.> (a single dot).
661		801
662		802
663	=item aio_rename $srcpath, $dstpath, $callback->($status)	803	=item aio_rename $srcpath, $dstpath, $callback->($status)
664		804
665	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	805	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
666	rename(2) and call the callback with the result code.	806	rename(2) and call the callback with the result code.
		807
		808	On systems that support the AIO::WD working directory abstraction
		809	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		810	of failing, C<rename> is called on the absolute path of C<$wd>.
667		811
668		812
669	=item aio_mkdir $pathname, $mode, $callback->($status)	813	=item aio_mkdir $pathname, $mode, $callback->($status)
670		814
671	Asynchronously mkdir (create) a directory and call the callback with	815	Asynchronously mkdir (create) a directory and call the callback with
…		…
675		819
676	=item aio_rmdir $pathname, $callback->($status)	820	=item aio_rmdir $pathname, $callback->($status)
677		821
678	Asynchronously rmdir (delete) a directory and call the callback with the	822	Asynchronously rmdir (delete) a directory and call the callback with the
679	result code.	823	result code.
		824
		825	On systems that support the AIO::WD working directory abstraction
		826	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		827	C<rmdir> is called on the absolute path of C<$wd>.
680		828
681		829
682	=item aio_readdir $pathname, $callback->($entries)	830	=item aio_readdir $pathname, $callback->($entries)
683		831
684	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	832	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
…		…
753	C<$type>'s are known, which can be used to speed up some algorithms.	901	C<$type>'s are known, which can be used to speed up some algorithms.
754		902
755	=back	903	=back
756		904
757		905
758	=item aio_load $path, $data, $callback->($status)	906	=item aio_load $pathname, $data, $callback->($status)
759		907
760	This is a composite request that tries to fully load the given file into	908	This is a composite request that tries to fully load the given file into
761	memory. Status is the same as with aio_read.	909	memory. Status is the same as with aio_read.
762		910
763	=cut	911	=cut
…		…
898	};	1046	};
899		1047
900	$grp	1048	$grp
901	}	1049	}
902		1050
903	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1051	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
904		1052
905	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1053	Scans a directory (similar to C<aio_readdir>) but additionally tries to
906	efficiently separate the entries of directory C<$path> into two sets of	1054	efficiently separate the entries of directory C<$path> into two sets of
907	names, directories you can recurse into (directories), and ones you cannot	1055	names, directories you can recurse into (directories), and ones you cannot
908	recurse into (everything else, including symlinks to directories).	1056	recurse into (everything else, including symlinks to directories).
…		…
965		1113
966	my $grp = aio_group $cb;	1114	my $grp = aio_group $cb;
967		1115
968	$maxreq = 4 if $maxreq <= 0;	1116	$maxreq = 4 if $maxreq <= 0;
969		1117
970	# stat once	1118	# get a wd object
971	aioreq_pri $pri;	1119	aioreq_pri $pri;
972	add $grp aio_stat $path, sub {	1120	add $grp aio_wd $path, sub {
		1121	$_[0]
973	return $grp->result () if $_[0];	1122	or return $grp->result ();
974	my $now = time;
975	my $hash1 = join ":", (stat _)[0,1,3,7,9];
976		1123
977	# read the directory entries	1124	my $wd = [shift, "."];
		1125
		1126	# stat once
978	aioreq_pri $pri;	1127	aioreq_pri $pri;
979	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1128	add $grp aio_stat $wd, sub {
980	my $entries = shift
981	or return $grp->result ();	1129	return $grp->result () if $_[0];
		1130	my $now = time;
		1131	my $hash1 = join ":", (stat _)[0,1,3,7,9];
982		1132
983	# stat the dir another time	1133	# read the directory entries
984	aioreq_pri $pri;	1134	aioreq_pri $pri;
		1135	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1136	my $entries = shift
		1137	or return $grp->result ();
		1138
		1139	# stat the dir another time
		1140	aioreq_pri $pri;
985	add $grp aio_stat $path, sub {	1141	add $grp aio_stat $wd, sub {
986	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1142	my $hash2 = join ":", (stat _)[0,1,3,7,9];
987		1143
988	my $ndirs;	1144	my $ndirs;
989		1145
990	# take the slow route if anything looks fishy	1146	# take the slow route if anything looks fishy
991	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1147	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
992	$ndirs = -1;	1148	$ndirs = -1;
993	} else {	1149	} else {
994	# if nlink == 2, we are finished	1150	# if nlink == 2, we are finished
995	# for non-posix-fs's, we rely on nlink < 2	1151	# for non-posix-fs's, we rely on nlink < 2
996	$ndirs = (stat _)[3] - 2	1152	$ndirs = (stat _)[3] - 2
997	or return $grp->result ([], $entries);	1153	or return $grp->result ([], $entries);
998	}	1154	}
999		1155
1000	my (@dirs, @nondirs);	1156	my (@dirs, @nondirs);
1001		1157
1002	my $statgrp = add $grp aio_group sub {	1158	my $statgrp = add $grp aio_group sub {
1003	$grp->result (\@dirs, \@nondirs);	1159	$grp->result (\@dirs, \@nondirs);
1004	};	1160	};
1005		1161
1006	limit $statgrp $maxreq;	1162	limit $statgrp $maxreq;
1007	feed $statgrp sub {	1163	feed $statgrp sub {
1008	return unless @$entries;	1164	return unless @$entries;
1009	my $entry = shift @$entries;	1165	my $entry = shift @$entries;
1010		1166
1011	aioreq_pri $pri;	1167	aioreq_pri $pri;
		1168	$wd->[1] = "$entry/.";
1012	add $statgrp aio_stat "$path/$entry/.", sub {	1169	add $statgrp aio_stat $wd, sub {
1013	if ($_[0] < 0) {	1170	if ($_[0] < 0) {
1014	push @nondirs, $entry;	1171	push @nondirs, $entry;
1015	} else {	1172	} else {
1016	# need to check for real directory	1173	# need to check for real directory
1017	aioreq_pri $pri;	1174	aioreq_pri $pri;
		1175	$wd->[1] = $entry;
1018	add $statgrp aio_lstat "$path/$entry", sub {	1176	add $statgrp aio_lstat $wd, sub {
1019	if (-d _) {	1177	if (-d _) {
1020	push @dirs, $entry;	1178	push @dirs, $entry;
1021		1179
1022	unless (--$ndirs) {	1180	unless (--$ndirs) {
1023	push @nondirs, @$entries;	1181	push @nondirs, @$entries;
1024	feed $statgrp;	1182	feed $statgrp;
		1183	}
		1184	} else {
		1185	push @nondirs, $entry;
1025	}	1186	}
1026	} else {
1027	push @nondirs, $entry;
1028	}	1187	}
1029	}	1188	}
1030	}	1189	};
1031	};	1190	};
1032	};	1191	};
1033	};	1192	};
1034	};	1193	};
1035	};	1194	};
1036		1195
1037	$grp	1196	$grp
1038	}	1197	}
1039		1198
1040	=item aio_rmtree $path, $callback->($status)	1199	=item aio_rmtree $pathname, $callback->($status)
1041		1200
1042	Delete a directory tree starting (and including) C<$path>, return the	1201	Delete a directory tree starting (and including) C<$path>, return the
1043	status of the final C<rmdir> only. This is a composite request that	1202	status of the final C<rmdir> only. This is a composite request that
1044	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1203	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1045	everything else.	1204	everything else.
1046		1205
1047	=cut	1206	=cut
1048		1207
…		…
1070	};	1229	};
1071		1230
1072	$grp	1231	$grp
1073	}	1232	}
1074		1233
		1234	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1235
		1236	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1237
		1238	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1239	they execute asynchronously and pass the return value to the callback.
		1240
		1241	Both calls can be used for a lot of things, some of which make more sense
		1242	to run asynchronously in their own thread, while some others make less
		1243	sense. For example, calls that block waiting for external events, such
		1244	as locking, will also lock down an I/O thread while it is waiting, which
		1245	can deadlock the whole I/O system. At the same time, there might be no
		1246	alternative to using a thread to wait.
		1247
		1248	So in general, you should only use these calls for things that do
		1249	(filesystem) I/O, not for things that wait for other events (network,
		1250	other processes), although if you are careful and know what you are doing,
		1251	you still can.
		1252
1075	=item aio_sync $callback->($status)	1253	=item aio_sync $callback->($status)
1076		1254
1077	Asynchronously call sync and call the callback when finished.	1255	Asynchronously call sync and call the callback when finished.
1078		1256
1079	=item aio_fsync $fh, $callback->($status)	1257	=item aio_fsync $fh, $callback->($status)
…		…
1106	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1284	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1107	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1285	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1108	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1286	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1109	manpage for details.	1287	manpage for details.
1110		1288
1111	=item aio_pathsync $path, $callback->($status)	1289	=item aio_pathsync $pathname, $callback->($status)
1112		1290
1113	This request tries to open, fsync and close the given path. This is a	1291	This request tries to open, fsync and close the given path. This is a
1114	composite request intended to sync directories after directory operations	1292	composite request intended to sync directories after directory operations
1115	(E.g. rename). This might not work on all operating systems or have any	1293	(E.g. rename). This might not work on all operating systems or have any
1116	specific effect, but usually it makes sure that directory changes get	1294	specific effect, but usually it makes sure that directory changes get
…		…
1168		1346
1169	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1347	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1170	scalars.	1348	scalars.
1171		1349
1172	It touches (reads or writes) all memory pages in the specified	1350	It touches (reads or writes) all memory pages in the specified
1173	range inside the scalar. All caveats and parameters are the same	1351	range inside the scalar. All caveats and parameters are the same
1174	as for C<aio_msync>, above, except for flags, which must be either	1352	as for C<aio_msync>, above, except for flags, which must be either
1175	C<0> (which reads all pages and ensures they are instantiated) or	1353	C<0> (which reads all pages and ensures they are instantiated) or
1176	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1354	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1177	writing an octet from it, which dirties the page).	1355	writing an octet from it, which dirties the page).
1178		1356
1179	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1357	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1180		1358
1181	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1359	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1212	documented under L<MISCELLANEOUS FUNCTIONS>.	1390	documented under L<MISCELLANEOUS FUNCTIONS>.
1213		1391
1214	Example: asynchronously lock all current and future pages into memory.	1392	Example: asynchronously lock all current and future pages into memory.
1215		1393
1216	aio_mlockall IO::AIO::MCL_FUTURE;	1394	aio_mlockall IO::AIO::MCL_FUTURE;
		1395
		1396	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1397
		1398	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1399	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1400	the ioctl is not available on your OS, then this request will fail with
		1401	C<ENOSYS>.
		1402
		1403	C<$start> is the starting offset to query extents for, C<$length> is the
		1404	size of the range to query - if it is C<undef>, then the whole file will
		1405	be queried.
		1406
		1407	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1408	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1409	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1410	the data portion.
		1411
		1412	C<$count> is the maximum number of extent records to return. If it is
		1413	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1414	case, if it is C<0>, then the callback receives the number of extents
		1415	instead of the extents themselves (which is unreliable, see below).
		1416
		1417	If an error occurs, the callback receives no arguments. The special
		1418	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1419
		1420	Otherwise, the callback receives an array reference with extent
		1421	structures. Each extent structure is an array reference itself, with the
		1422	following members:
		1423
		1424	[$logical, $physical, $length, $flags]
		1425
		1426	Flags is any combination of the following flag values (typically either C<0>
		1427	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1428
		1429	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1430	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1431	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1432	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1433	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1434	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1435
		1436	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1437	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1438	it to return all extents of a range for files with large number of
		1439	extents. The code works around all these issues if C<$count> is undef.
1217		1440
1218	=item aio_group $callback->(...)	1441	=item aio_group $callback->(...)
1219		1442
1220	This is a very special aio request: Instead of doing something, it is a	1443	This is a very special aio request: Instead of doing something, it is a
1221	container for other aio requests, which is useful if you want to bundle	1444	container for other aio requests, which is useful if you want to bundle
…		…
1258	like sleep and file handle readable/writable, the overhead this creates is	1481	like sleep and file handle readable/writable, the overhead this creates is
1259	immense (it blocks a thread for a long time) so do not use this function	1482	immense (it blocks a thread for a long time) so do not use this function
1260	except to put your application under artificial I/O pressure.	1483	except to put your application under artificial I/O pressure.
1261		1484
1262	=back	1485	=back
		1486
		1487
		1488	=head2 IO::AIO::WD - multiple working directories
		1489
		1490	Your process only has one current working directory, which is used by all
		1491	threads. This makes it hard to use relative paths (some other component
		1492	could call C<chdir> at any time, and it is hard to control when the path
		1493	will be used by IO::AIO).
		1494
		1495	One solution for this is to always use absolute paths. This usually works,
		1496	but can be quite slow (the kernel has to walk the whole path on every
		1497	access), and can also be a hassle to implement.
		1498
		1499	Newer POSIX systems have a number of functions (openat, fdopendir,
		1500	futimensat and so on) that make it possible to specify working directories
		1501	per operation.
		1502
		1503	For portability, and because the clowns who "designed", or shall I write,
		1504	perpetrated this new interface were obviously half-drunk, this abstraction
		1505	cannot be perfect, though.
		1506
		1507	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1508	object. This object stores the canonicalised, absolute version of the
		1509	path, and on systems that allow it, also a directory file descriptor.
		1510
		1511	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1512	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1513	object and a pathname instead (or the IO::AIO::WD object alone, which
		1514	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1515	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1516	to that IO::AIO::WD object.
		1517
		1518	For example, to get a wd object for F</etc> and then stat F<passwd>
		1519	inside, you would write:
		1520
		1521	aio_wd "/etc", sub {
		1522	my $etcdir = shift;
		1523
		1524	# although $etcdir can be undef on error, there is generally no reason
		1525	# to check for errors here, as aio_stat will fail with ENOENT
		1526	# when $etcdir is undef.
		1527
		1528	aio_stat [$etcdir, "passwd"], sub {
		1529	# yay
		1530	};
		1531	};
		1532
		1533	The fact that C<aio_wd> is a request and not a normal function shows that
		1534	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1535	which is why it is done asynchronously.
		1536
		1537	To stat the directory obtained with C<aio_wd> above, one could write
		1538	either of the following three request calls:
		1539
		1540	aio_lstat "/etc" , sub { ... # pathname as normal string
		1541	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1542	aio_lstat $wd , sub { ... # shorthand for the previous
		1543
		1544	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1545	object and the pathname string, so you could write the following without
		1546	causing any issues due to C<$path> getting reused:
		1547
		1548	my $path = [$wd, undef];
		1549
		1550	for my $name (qw(abc def ghi)) {
		1551	$path->[1] = $name;
		1552	aio_stat $path, sub {
		1553	# ...
		1554	};
		1555	}
		1556
		1557	There are some caveats: when directories get renamed (or deleted), the
		1558	pathname string doesn't change, so will point to the new directory (or
		1559	nowhere at all), while the directory fd, if available on the system,
		1560	will still point to the original directory. Most functions accepting a
		1561	pathname will use the directory fd on newer systems, and the string on
		1562	older systems. Some functions (such as realpath) will always rely on the
		1563	string form of the pathname.
		1564
		1565	So this functionality is mainly useful to get some protection against
		1566	C<chdir>, to easily get an absolute path out of a relative path for future
		1567	reference, and to speed up doing many operations in the same directory
		1568	(e.g. when stat'ing all files in a directory).
		1569
		1570	The following functions implement this working directory abstraction:
		1571
		1572	=over 4
		1573
		1574	=item aio_wd $pathname, $callback->($wd)
		1575
		1576	Asynchonously canonicalise the given pathname and convert it to an
		1577	IO::AIO::WD object representing it. If possible and supported on the
		1578	system, also open a directory fd to speed up pathname resolution relative
		1579	to this working directory.
		1580
		1581	If something goes wrong, then C<undef> is passwd to the callback instead
		1582	of a working directory object and C<$!> is set appropriately. Since
		1583	passing C<undef> as working directory component of a pathname fails the
		1584	request with C<ENOENT>, there is often no need for error checking in the
		1585	C<aio_wd> callback, as future requests using the value will fail in the
		1586	expected way.
		1587
		1588	=item IO::AIO::CWD
		1589
		1590	This is a compiletime constant (object) that represents the process
		1591	current working directory.
		1592
		1593	Specifying this object as working directory object for a pathname is as if
		1594	the pathname would be specified directly, without a directory object. For
		1595	example, these calls are functionally identical:
		1596
		1597	aio_stat "somefile", sub { ... };
		1598	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1599
		1600	=back
		1601
		1602	To recover the path associated with an IO::AIO::WD object, you can use
		1603	C<aio_realpath>:
		1604
		1605	aio_realpath $wd, sub {
		1606	warn "path is $_[0]\n";
		1607	};
		1608
		1609	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1610	sometimes, fall back to using an absolue path.
1263		1611
1264	=head2 IO::AIO::REQ CLASS	1612	=head2 IO::AIO::REQ CLASS
1265		1613
1266	All non-aggregate C<aio_*> functions return an object of this class when	1614	All non-aggregate C<aio_*> functions return an object of this class when
1267	called in non-void context.	1615	called in non-void context.
…		…
1385		1733
1386	Sets a feeder/generator on this group: every group can have an attached	1734	Sets a feeder/generator on this group: every group can have an attached
1387	generator that generates requests if idle. The idea behind this is that,	1735	generator that generates requests if idle. The idea behind this is that,
1388	although you could just queue as many requests as you want in a group,	1736	although you could just queue as many requests as you want in a group,
1389	this might starve other requests for a potentially long time. For example,	1737	this might starve other requests for a potentially long time. For example,
1390	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1738	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1391	delaying any later requests for a long time.	1739	requests, delaying any later requests for a long time.
1392		1740
1393	To avoid this, and allow incremental generation of requests, you can	1741	To avoid this, and allow incremental generation of requests, you can
1394	instead a group and set a feeder on it that generates those requests. The	1742	instead a group and set a feeder on it that generates those requests. The
1395	feed callback will be called whenever there are few enough (see C<limit>,	1743	feed callback will be called whenever there are few enough (see C<limit>,
1396	below) requests active in the group itself and is expected to queue more	1744	below) requests active in the group itself and is expected to queue more
…		…
1445		1793
1446	See C<poll_cb> for an example.	1794	See C<poll_cb> for an example.
1447		1795
1448	=item IO::AIO::poll_cb	1796	=item IO::AIO::poll_cb
1449		1797
1450	Process some outstanding events on the result pipe. You have to call	1798	Process some requests that have reached the result phase (i.e. they have
		1799	been executed but the results are not yet reported). You have to call
		1800	this "regularly" to finish outstanding requests.
		1801
1451	this regularly. Returns C<0> if all events could be processed (or there	1802	Returns C<0> if all events could be processed (or there were no
1452	were no events to process), or C<-1> if it returned earlier for whatever	1803	events to process), or C<-1> if it returned earlier for whatever
1453	reason. Returns immediately when no events are outstanding. The amount of	1804	reason. Returns immediately when no events are outstanding. The amount
1454	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1805	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1455	C<IO::AIO::max_poll_time>.	1806	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1456		1807
1457	If not all requests were processed for whatever reason, the filehandle	1808	If not all requests were processed for whatever reason, the poll file
1458	will still be ready when C<poll_cb> returns, so normally you don't have to	1809	descriptor will still be ready when C<poll_cb> returns, so normally you
1459	do anything special to have it called later.	1810	don't have to do anything special to have it called later.
1460		1811
1461	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1812	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1462	ready, it can be beneficial to call this function from loops which submit	1813	ready, it can be beneficial to call this function from loops which submit
1463	a lot of requests, to make sure the results get processed when they become	1814	a lot of requests, to make sure the results get processed when they become
1464	available and not just when the loop is finished and the event loop takes	1815	available and not just when the loop is finished and the event loop takes
…		…
1473	poll => 'r', async => 1,	1824	poll => 'r', async => 1,
1474	cb => \&IO::AIO::poll_cb);	1825	cb => \&IO::AIO::poll_cb);
1475		1826
1476	=item IO::AIO::poll_wait	1827	=item IO::AIO::poll_wait
1477		1828
1478	If there are any outstanding requests and none of them in the result	1829	Wait until either at least one request is in the result phase or no
1479	phase, wait till the result filehandle becomes ready for reading (simply	1830	requests are outstanding anymore.
1480	does a C<select> on the filehandle. This is useful if you want to	1831
1481	synchronously wait for some requests to finish).	1832	This is useful if you want to synchronously wait for some requests to
		1833	become ready, without actually handling them.
1482		1834
1483	See C<nreqs> for an example.	1835	See C<nreqs> for an example.
1484		1836
1485	=item IO::AIO::poll	1837	=item IO::AIO::poll
1486		1838
…		…
1607		1959
1608	This is a very bad function to use in interactive programs because it	1960	This is a very bad function to use in interactive programs because it
1609	blocks, and a bad way to reduce concurrency because it is inexact: Better	1961	blocks, and a bad way to reduce concurrency because it is inexact: Better
1610	use an C<aio_group> together with a feed callback.	1962	use an C<aio_group> together with a feed callback.
1611		1963
1612	It's main use is in scripts without an event loop - when you want to stat	1964	Its main use is in scripts without an event loop - when you want to stat
1613	a lot of files, you can write somehting like this:	1965	a lot of files, you can write somehting like this:
1614		1966
1615	IO::AIO::max_outstanding 32;	1967	IO::AIO::max_outstanding 32;
1616		1968
1617	for my $path (...) {	1969	for my $path (...) {
…		…
1657		2009
1658	=back	2010	=back
1659		2011
1660	=head3 MISCELLANEOUS FUNCTIONS	2012	=head3 MISCELLANEOUS FUNCTIONS
1661		2013
1662	IO::AIO implements some functions that might be useful, but are not	2014	IO::AIO implements some functions that are useful when you want to use
1663	asynchronous.	2015	some "Advanced I/O" function not available to in Perl, without going the
		2016	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2017	counterpart.
1664		2018
1665	=over 4	2019	=over 4
1666		2020
1667	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2021	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1668		2022
…		…
1705	ENOSYS, otherwise the return value of C<mprotect>.	2059	ENOSYS, otherwise the return value of C<mprotect>.
1706		2060
1707	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2061	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1708		2062
1709	Memory-maps a file (or anonymous memory range) and attaches it to the	2063	Memory-maps a file (or anonymous memory range) and attaches it to the
1710	given C<$scalar>, which will act like a string scalar.	2064	given C<$scalar>, which will act like a string scalar. Returns true on
		2065	success, and false otherwise.
1711		2066
1712	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2067	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1713	change the string length, and most read-only operations such as copying it	2068	change the string length, and most read-only operations such as copying it
1714	or searching it with regexes and so on.	2069	or searching it with regexes and so on.
1715		2070
…		…
1726	filesize.	2081	filesize.
1727		2082
1728	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2083	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1729	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2084	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1730		2085
1731	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2086	C<$flags> can be a combination of
1732	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2087	C<IO::AIO::MAP_SHARED> or
1733	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2088	C<IO::AIO::MAP_PRIVATE>,
		2089	or a number of system-specific flags (when not available, the are C<0>):
1734	(which is set to C<MAP_ANON> if your system only provides this	2090	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1735	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2091	C<IO::AIO::MAP_LOCKED>,
1736	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2092	C<IO::AIO::MAP_NORESERVE>,
		2093	C<IO::AIO::MAP_POPULATE>,
1737	C<IO::AIO::MAP_NONBLOCK>	2094	C<IO::AIO::MAP_NONBLOCK>,
		2095	C<IO::AIO::MAP_FIXED>,
		2096	C<IO::AIO::MAP_GROWSDOWN>,
		2097	C<IO::AIO::MAP_32BIT>,
		2098	C<IO::AIO::MAP_HUGETLB> or
		2099	C<IO::AIO::MAP_STACK>.
1738		2100
1739	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2101	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1740		2102
1741	C<$offset> is the offset from the start of the file - it generally must be	2103	C<$offset> is the offset from the start of the file - it generally must be
1742	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2104	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1767		2129
1768	Calls the C<munlockall> function.	2130	Calls the C<munlockall> function.
1769		2131
1770	On systems that do not implement C<munlockall>, this function returns	2132	On systems that do not implement C<munlockall>, this function returns
1771	ENOSYS, otherwise the return value of C<munlockall>.	2133	ENOSYS, otherwise the return value of C<munlockall>.
		2134
		2135	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2136
		2137	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2138	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2139	should be the file offset.
		2140
		2141	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2142	silently corrupt the data in this case.
		2143
		2144	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2145	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2146	C<IO::AIO::SPLICE_F_GIFT>.
		2147
		2148	See the C<splice(2)> manpage for details.
		2149
		2150	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2151
		2152	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2153	description for C<IO::AIO::splice> above for details.
		2154
		2155	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2156
		2157	Attempts to query or change the pipe buffer size. Obviously works only
		2158	on pipes, and currently works only on GNU/Linux systems, and fails with
		2159	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2160	size on other systems, drop me a note.
		2161
		2162	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2163
		2164	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2165	C<$flags> is missing or C<0>, then this should be the same as a call to
		2166	perl's built-in C<pipe> function and create a new pipe, and works on
		2167	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2168	(..., 4096, O_BINARY)>.
		2169
		2170	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2171	the given flags (Linux 2.6.27, glibc 2.9).
		2172
		2173	On success, the read and write file handles are returned.
		2174
		2175	On error, nothing will be returned. If the pipe2 syscall is missing and
		2176	C<$flags> is non-zero, fails with C<ENOSYS>.
		2177
		2178	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2179	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2180	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1772		2181
1773	=back	2182	=back
1774		2183
1775	=cut	2184	=cut
1776		2185

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs. Revision 1.259 by root, Tue Feb 23 19:42:43 2016 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs.
Revision 1.259 by root, Tue Feb 23 19:42:43 2016 UTC