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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC vs.
Revision 1.254 by root, Thu Jun 25 13:42:18 2015 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;
…		…
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 = '3.9';	172	our $VERSION = 4.32;
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_sync aio_fsync	176	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	177	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
		178	aio_pathsync aio_readahead aio_fiemap
179	aio_rename aio_link aio_move aio_copy aio_group	179	aio_rename aio_link aio_move aio_copy aio_group
180	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
181	aio_chmod aio_utime aio_truncate	181	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_mlock aio_mlockall	182	aio_msync aio_mtouch aio_mlock aio_mlockall
183	aio_statvfs);	183	aio_statvfs
		184	aio_wd);
184		185
185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
187	min_parallel max_parallel max_idle idle_timeout	188	min_parallel max_parallel max_idle idle_timeout
188	nreqs nready npending nthreads	189	nreqs nready npending nthreads
…		…
200		201
201	=head1 FUNCTIONS	202	=head1 FUNCTIONS
202		203
203	=head2 QUICK OVERVIEW	204	=head2 QUICK OVERVIEW
204		205
205	This section simply lists the prototypes of the most important functions	206	This section simply lists the prototypes most of the functions for
206	for quick reference. See the following sections for function-by-function	207	quick reference. See the following sections for function-by-function
207	documentation.	208	documentation.
208		209
		210	aio_wd $pathname, $callback->($wd)
209	aio_open $pathname, $flags, $mode, $callback->($fh)	211	aio_open $pathname, $flags, $mode, $callback->($fh)
210	aio_close $fh, $callback->($status)	212	aio_close $fh, $callback->($status)
		213	aio_seek $fh,$offset,$whence, $callback->($offs)
211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214	aio_readahead $fh,$offset,$length, $callback->($retval)	217	aio_readahead $fh,$offset,$length, $callback->($retval)
215	aio_stat $fh_or_path, $callback->($status)	218	aio_stat $fh_or_path, $callback->($status)
216	aio_lstat $fh, $callback->($status)	219	aio_lstat $fh, $callback->($status)
217	aio_statvfs $fh_or_path, $callback->($statvfs)	220	aio_statvfs $fh_or_path, $callback->($statvfs)
218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219	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)
220	aio_truncate $fh_or_path, $offset, $callback->($status)	224	aio_truncate $fh_or_path, $offset, $callback->($status)
221	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)
222	aio_unlink $pathname, $callback->($status)	227	aio_unlink $pathname, $callback->($status)
223	aio_mknod $path, $mode, $dev, $callback->($status)	228	aio_mknod $pathname, $mode, $dev, $callback->($status)
224	aio_link $srcpath, $dstpath, $callback->($status)	229	aio_link $srcpath, $dstpath, $callback->($status)
225	aio_symlink $srcpath, $dstpath, $callback->($status)	230	aio_symlink $srcpath, $dstpath, $callback->($status)
226	aio_readlink $path, $callback->($link)	231	aio_readlink $pathname, $callback->($link)
		232	aio_realpath $pathname, $callback->($path)
227	aio_rename $srcpath, $dstpath, $callback->($status)	233	aio_rename $srcpath, $dstpath, $callback->($status)
228	aio_mkdir $pathname, $mode, $callback->($status)	234	aio_mkdir $pathname, $mode, $callback->($status)
229	aio_rmdir $pathname, $callback->($status)	235	aio_rmdir $pathname, $callback->($status)
230	aio_readdir $pathname, $callback->($entries)	236	aio_readdir $pathname, $callback->($entries)
231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233	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)
234	aio_load $path, $data, $callback->($status)	241	aio_load $pathname, $data, $callback->($status)
235	aio_copy $srcpath, $dstpath, $callback->($status)	242	aio_copy $srcpath, $dstpath, $callback->($status)
236	aio_move $srcpath, $dstpath, $callback->($status)	243	aio_move $srcpath, $dstpath, $callback->($status)
237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238	aio_rmtree $path, $callback->($status)	244	aio_rmtree $pathname, $callback->($status)
239	aio_sync $callback->($status)	245	aio_sync $callback->($status)
		246	aio_syncfs $fh, $callback->($status)
240	aio_fsync $fh, $callback->($status)	247	aio_fsync $fh, $callback->($status)
241	aio_fdatasync $fh, $callback->($status)	248	aio_fdatasync $fh, $callback->($status)
242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	249	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243	aio_pathsync $path, $callback->($status)	250	aio_pathsync $pathname, $callback->($status)
244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	251	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	252	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	253	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247	aio_mlockall $flags, $callback->($status)	254	aio_mlockall $flags, $callback->($status)
248	aio_group $callback->(...)	255	aio_group $callback->(...)
…		…
266	IO::AIO::nready	273	IO::AIO::nready
267	IO::AIO::npending	274	IO::AIO::npending
268		275
269	IO::AIO::sendfile $ofh, $ifh, $offset, $count	276	IO::AIO::sendfile $ofh, $ifh, $offset, $count
270	IO::AIO::fadvise $fh, $offset, $len, $advice	277	IO::AIO::fadvise $fh, $offset, $len, $advice
		278	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		279	IO::AIO::munmap $scalar
271	IO::AIO::madvise $scalar, $offset, $length, $advice	280	IO::AIO::madvise $scalar, $offset, $length, $advice
272	IO::AIO::mprotect $scalar, $offset, $length, $protect	281	IO::AIO::mprotect $scalar, $offset, $length, $protect
273	IO::AIO::munlock $scalar, $offset = 0, $length = undef	282	IO::AIO::munlock $scalar, $offset = 0, $length = undef
274	IO::AIO::munlockall	283	IO::AIO::munlockall
275		284
276	=head2 AIO REQUEST FUNCTIONS	285	=head2 API NOTES
277		286
278	All the C<aio_*> calls are more or less thin wrappers around the syscall	287	All the C<aio_*> calls are more or less thin wrappers around the syscall
279	with the same name (sans C<aio_>). The arguments are similar or identical,	288	with the same name (sans C<aio_>). The arguments are similar or identical,
280	and they all accept an additional (and optional) C<$callback> argument	289	and they all accept an additional (and optional) C<$callback> argument
281	which must be a code reference. This code reference will get called with	290	which must be a code reference. This code reference will be called after
282	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	291	the syscall has been executed in an asynchronous fashion. The results
283	perl, which usually delivers "false") as its sole argument after the given	292	of the request will be passed as arguments to the callback (and, if an
284	syscall has been executed asynchronously.	293	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		294	most syscalls return C<-1> on error, unlike perl, which usually delivers
		295	"false").
		296
		297	Some requests (such as C<aio_readdir>) pass the actual results and
		298	communicate failures by passing C<undef>.
285		299
286	All functions expecting a filehandle keep a copy of the filehandle	300	All functions expecting a filehandle keep a copy of the filehandle
287	internally until the request has finished.	301	internally until the request has finished.
288		302
289	All functions return request objects of type L<IO::AIO::REQ> that allow	303	All functions return request objects of type L<IO::AIO::REQ> that allow
290	further manipulation of those requests while they are in-flight.	304	further manipulation of those requests while they are in-flight.
291		305
292	The pathnames you pass to these routines I<must> be absolute and	306	The pathnames you pass to these routines I<should> be absolute. The
293	encoded as octets. The reason for the former is that at the time the	307	reason for this is that at the time the request is being executed, the
294	request is being executed, the current working directory could have	308	current working directory could have changed. Alternatively, you can
295	changed. Alternatively, you can make sure that you never change the	309	make sure that you never change the current working directory anywhere
296	current working directory anywhere in the program and then use relative	310	in the program and then use relative paths. You can also take advantage
297	paths.	311	of IO::AIOs working directory abstraction, that lets you specify paths
		312	relative to some previously-opened "working directory object" - see the
		313	description of the C<IO::AIO::WD> class later in this document.
298		314
299	To encode pathnames as octets, either make sure you either: a) always pass	315	To encode pathnames as octets, either make sure you either: a) always pass
300	in filenames you got from outside (command line, readdir etc.) without	316	in filenames you got from outside (command line, readdir etc.) without
301	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	317	tinkering, b) are in your native filesystem encoding, c) use the Encode
302	your pathnames to the locale (or other) encoding in effect in the user	318	module and encode your pathnames to the locale (or other) encoding in
303	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	319	effect in the user environment, d) use Glib::filename_from_unicode on
304	use something else to ensure your scalar has the correct contents.	320	unicode filenames or e) use something else to ensure your scalar has the
		321	correct contents.
305		322
306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	323	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
307	handles correctly whether it is set or not.	324	handles correctly whether it is set or not.
		325
		326	=head2 AIO REQUEST FUNCTIONS
308		327
309	=over 4	328	=over 4
310		329
311	=item $prev_pri = aioreq_pri [$pri]	330	=item $prev_pri = aioreq_pri [$pri]
312		331
…		…
342		361
343		362
344	=item aio_open $pathname, $flags, $mode, $callback->($fh)	363	=item aio_open $pathname, $flags, $mode, $callback->($fh)
345		364
346	Asynchronously open or create a file and call the callback with a newly	365	Asynchronously open or create a file and call the callback with a newly
347	created filehandle for the file.	366	created filehandle for the file (or C<undef> in case of an error).
348		367
349	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	368	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
350	for an explanation.	369	for an explanation.
351		370
352	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	371	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
395	Or in other words: the file descriptor will be closed, but it will not be	414	Or in other words: the file descriptor will be closed, but it will not be
396	free for reuse until the perl filehandle is closed.	415	free for reuse until the perl filehandle is closed.
397		416
398	=cut	417	=cut
399		418
		419	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		420
		421	Seeks the filehandle to the new C<$offset>, similarly to perl's
		422	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		423	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		424	C<IO::AIO::SEEK_END>).
		425
		426	The resulting absolute offset will be passed to the callback, or C<-1> in
		427	case of an error.
		428
		429	In theory, the C<$whence> constants could be different than the
		430	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		431	so don't panic.
		432
		433	As a GNU/Linux (and maybe Solaris) extension, also the constants
		434	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		435	could be found. No guarantees about suitability for use in C<aio_seek> or
		436	Perl's C<sysseek> can be made though, although I would naively assume they
		437	"just work".
		438
400	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	439	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
401		440
402	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	441	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
403		442
404	Reads or writes C<$length> bytes from or to the specified C<$fh> and	443	Reads or writes C<$length> bytes from or to the specified C<$fh> and
…		…
436		475
437	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	476	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
438	reading at byte offset C<$in_offset>, and starts writing at the current	477	reading at byte offset C<$in_offset>, and starts writing at the current
439	file offset of C<$out_fh>. Because of that, it is not safe to issue more	478	file offset of C<$out_fh>. Because of that, it is not safe to issue more
440	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	479	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
441	other.	480	other. The same C<$in_fh> works fine though, as this function does not
		481	move or use the file offset of C<$in_fh>.
442		482
443	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than	483	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
444	are written, and there is no way to find out how many bytes have been read	484	are written, and there is no way to find out how many more bytes have been
445	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of	485	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
446	bytes written to C<$out_fh>. Only if the result value equals C<$length>	486	number of bytes written to C<$out_fh>. Only if the result value equals
447	one can assume that C<$length> bytes have been read.	487	C<$length> one can assume that C<$length> bytes have been read.
448		488
449	Unlike with other C<aio_> functions, it makes a lot of sense to use	489	Unlike with other C<aio_> functions, it makes a lot of sense to use
450	C<aio_sendfile> on non-blocking sockets, as long as one end (typically	490	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
451	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while	491	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
452	the socket I/O will be non-blocking. Note, however, that you can run into	492	the socket I/O will be non-blocking. Note, however, that you can run
453	a trap where C<aio_sendfile> reads some data with readahead, then fails	493	into a trap where C<aio_sendfile> reads some data with readahead, then
454	to write all data, and when the socket is ready the next time, the data	494	fails to write all data, and when the socket is ready the next time, the
455	in the cache is already lost, forcing C<aio_sendfile> to again hit the	495	data in the cache is already lost, forcing C<aio_sendfile> to again hit
456	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage	496	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
457	much better.	497	resource usage.
458		498
459	This call tries to make use of a native C<sendfile> syscall to provide	499	This call tries to make use of a native C<sendfile>-like syscall to
460	zero-copy operation. For this to work, C<$out_fh> should refer to a	500	provide zero-copy operation. For this to work, C<$out_fh> should refer to
461	socket, and C<$in_fh> should refer to an mmap'able file.	501	a socket, and C<$in_fh> should refer to an mmap'able file.
462		502
463	If a native sendfile cannot be found or it fails with C<ENOSYS>,	503	If a native sendfile cannot be found or it fails with C<ENOSYS>,
464	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	504	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
465	it will be emulated, so you can call C<aio_sendfile> on any type of	505	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
466	filehandle regardless of the limitations of the operating system.	506	type of filehandle regardless of the limitations of the operating system.
		507
		508	As native sendfile syscalls (as practically any non-POSIX interface hacked
		509	together in a hurry to improve benchmark numbers) tend to be rather buggy
		510	on many systems, this implementation tries to work around some known bugs
		511	in Linux and FreeBSD kernels (probably others, too), but that might fail,
		512	so you really really should check the return value of C<aio_sendfile> -
		513	fewre bytes than expected might have been transferred.
467		514
468		515
469	=item aio_readahead $fh,$offset,$length, $callback->($retval)	516	=item aio_readahead $fh,$offset,$length, $callback->($retval)
470		517
471	C<aio_readahead> populates the page cache with data from a file so that	518	C<aio_readahead> populates the page cache with data from a file so that
…		…
555	namemax => 255,	602	namemax => 255,
556	frsize => 1024,	603	frsize => 1024,
557	fsid => 1810	604	fsid => 1810
558	}	605	}
559		606
		607	Here is a (likely partial - send me updates!) list of fsid values used by
		608	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		609
		610	0x0000adf5 adfs
		611	0x0000adff affs
		612	0x5346414f afs
		613	0x09041934 anon-inode filesystem
		614	0x00000187 autofs
		615	0x42465331 befs
		616	0x1badface bfs
		617	0x42494e4d binfmt_misc
		618	0x9123683e btrfs
		619	0x0027e0eb cgroupfs
		620	0xff534d42 cifs
		621	0x73757245 coda
		622	0x012ff7b7 coh
		623	0x28cd3d45 cramfs
		624	0x453dcd28 cramfs-wend (wrong endianness)
		625	0x64626720 debugfs
		626	0x00001373 devfs
		627	0x00001cd1 devpts
		628	0x0000f15f ecryptfs
		629	0x00414a53 efs
		630	0x0000137d ext
		631	0x0000ef53 ext2/ext3
		632	0x0000ef51 ext2
		633	0x00004006 fat
		634	0x65735546 fuseblk
		635	0x65735543 fusectl
		636	0x0bad1dea futexfs
		637	0x01161970 gfs2
		638	0x47504653 gpfs
		639	0x00004244 hfs
		640	0xf995e849 hpfs
		641	0x958458f6 hugetlbfs
		642	0x2bad1dea inotifyfs
		643	0x00009660 isofs
		644	0x000072b6 jffs2
		645	0x3153464a jfs
		646	0x6b414653 k-afs
		647	0x0bd00bd0 lustre
		648	0x0000137f minix
		649	0x0000138f minix 30 char names
		650	0x00002468 minix v2
		651	0x00002478 minix v2 30 char names
		652	0x00004d5a minix v3
		653	0x19800202 mqueue
		654	0x00004d44 msdos
		655	0x0000564c novell
		656	0x00006969 nfs
		657	0x6e667364 nfsd
		658	0x00003434 nilfs
		659	0x5346544e ntfs
		660	0x00009fa1 openprom
		661	0x7461636F ocfs2
		662	0x00009fa0 proc
		663	0x6165676c pstorefs
		664	0x0000002f qnx4
		665	0x858458f6 ramfs
		666	0x52654973 reiserfs
		667	0x00007275 romfs
		668	0x67596969 rpc_pipefs
		669	0x73636673 securityfs
		670	0xf97cff8c selinux
		671	0x0000517b smb
		672	0x534f434b sockfs
		673	0x73717368 squashfs
		674	0x62656572 sysfs
		675	0x012ff7b6 sysv2
		676	0x012ff7b5 sysv4
		677	0x01021994 tmpfs
		678	0x15013346 udf
		679	0x00011954 ufs
		680	0x54190100 ufs byteswapped
		681	0x00009fa2 usbdevfs
		682	0x01021997 v9fs
		683	0xa501fcf5 vxfs
		684	0xabba1974 xenfs
		685	0x012ff7b4 xenix
		686	0x58465342 xfs
		687	0x012fd16d xia
560		688
561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	689	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
562		690
563	Works like perl's C<utime> function (including the special case of $atime	691	Works like perl's C<utime> function (including the special case of $atime
564	and $mtime being undef). Fractional times are supported if the underlying	692	and $mtime being undef). Fractional times are supported if the underlying
…		…
592	=item aio_truncate $fh_or_path, $offset, $callback->($status)	720	=item aio_truncate $fh_or_path, $offset, $callback->($status)
593		721
594	Works like truncate(2) or ftruncate(2).	722	Works like truncate(2) or ftruncate(2).
595		723
596		724
		725	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		726
		727	Allocates or frees disk space according to the C<$mode> argument. See the
		728	linux C<fallocate> documentation for details.
		729
		730	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		731	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		732	to deallocate a file range.
		733
		734	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		735	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		736	your L<fallocate(2)> manpage).
		737
		738	The file system block size used by C<fallocate> is presumably the
		739	C<f_bsize> returned by C<statvfs>.
		740
		741	If C<fallocate> isn't available or cannot be emulated (currently no
		742	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		743
		744
597	=item aio_chmod $fh_or_path, $mode, $callback->($status)	745	=item aio_chmod $fh_or_path, $mode, $callback->($status)
598		746
599	Works like perl's C<chmod> function.	747	Works like perl's C<chmod> function.
600		748
601		749
…		…
603		751
604	Asynchronously unlink (delete) a file and call the callback with the	752	Asynchronously unlink (delete) a file and call the callback with the
605	result code.	753	result code.
606		754
607		755
608	=item aio_mknod $path, $mode, $dev, $callback->($status)	756	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
609		757
610	[EXPERIMENTAL]	758	[EXPERIMENTAL]
611		759
612	Asynchronously create a device node (or fifo). See mknod(2).	760	Asynchronously create a device node (or fifo). See mknod(2).
613		761
614	The only (POSIX-) portable way of calling this function is:	762	The only (POSIX-) portable way of calling this function is:
615		763
616	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	764	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
617		765
618	See C<aio_stat> for info about some potentially helpful extra constants	766	See C<aio_stat> for info about some potentially helpful extra constants
619	and functions.	767	and functions.
620		768
621	=item aio_link $srcpath, $dstpath, $callback->($status)	769	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
628		776
629	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	777	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
630	the path C<$dstpath> and call the callback with the result code.	778	the path C<$dstpath> and call the callback with the result code.
631		779
632		780
633	=item aio_readlink $path, $callback->($link)	781	=item aio_readlink $pathname, $callback->($link)
634		782
635	Asynchronously read the symlink specified by C<$path> and pass it to	783	Asynchronously read the symlink specified by C<$path> and pass it to
636	the callback. If an error occurs, nothing or undef gets passed to the	784	the callback. If an error occurs, nothing or undef gets passed to the
637	callback.	785	callback.
638		786
639		787
		788	=item aio_realpath $pathname, $callback->($path)
		789
		790	Asynchronously make the path absolute and resolve any symlinks in
		791	C<$path>. The resulting path only consists of directories (same as
		792	L<Cwd::realpath>).
		793
		794	This request can be used to get the absolute path of the current working
		795	directory by passing it a path of F<.> (a single dot).
		796
		797
640	=item aio_rename $srcpath, $dstpath, $callback->($status)	798	=item aio_rename $srcpath, $dstpath, $callback->($status)
641		799
642	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	800	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
643	rename(2) and call the callback with the result code.	801	rename(2) and call the callback with the result code.
		802
		803	On systems that support the AIO::WD working directory abstraction
		804	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		805	of failing, C<rename> is called on the absolute path of C<$wd>.
644		806
645		807
646	=item aio_mkdir $pathname, $mode, $callback->($status)	808	=item aio_mkdir $pathname, $mode, $callback->($status)
647		809
648	Asynchronously mkdir (create) a directory and call the callback with	810	Asynchronously mkdir (create) a directory and call the callback with
…		…
653	=item aio_rmdir $pathname, $callback->($status)	815	=item aio_rmdir $pathname, $callback->($status)
654		816
655	Asynchronously rmdir (delete) a directory and call the callback with the	817	Asynchronously rmdir (delete) a directory and call the callback with the
656	result code.	818	result code.
657		819
		820	On systems that support the AIO::WD working directory abstraction
		821	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		822	C<rmdir> is called on the absolute path of C<$wd>.
		823
658		824
659	=item aio_readdir $pathname, $callback->($entries)	825	=item aio_readdir $pathname, $callback->($entries)
660		826
661	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	827	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
662	directory (i.e. opendir + readdir + closedir). The entries will not be	828	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
666	array-ref with the filenames.	832	array-ref with the filenames.
667		833
668		834
669	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	835	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
670		836
671	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	837	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
672	behaviour and output format. In case of an error, C<$entries> will be	838	tune behaviour and output format. In case of an error, C<$entries> will be
673	C<undef>.	839	C<undef>.
674		840
675	The flags are a combination of the following constants, ORed together (the	841	The flags are a combination of the following constants, ORed together (the
676	flags will also be passed to the callback, possibly modified):	842	flags will also be passed to the callback, possibly modified):
677		843
…		…
724		890
725	=item IO::AIO::READDIR_FOUND_UNKNOWN	891	=item IO::AIO::READDIR_FOUND_UNKNOWN
726		892
727	This flag should not be set when calling C<aio_readdirx>. Instead, it	893	This flag should not be set when calling C<aio_readdirx>. Instead, it
728	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	894	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
729	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	895	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
730	C<$type>'s are known, which can be used to speed up some algorithms.	896	C<$type>'s are known, which can be used to speed up some algorithms.
731		897
732	=back	898	=back
733		899
734		900
735	=item aio_load $path, $data, $callback->($status)	901	=item aio_load $pathname, $data, $callback->($status)
736		902
737	This is a composite request that tries to fully load the given file into	903	This is a composite request that tries to fully load the given file into
738	memory. Status is the same as with aio_read.	904	memory. Status is the same as with aio_read.
739		905
740	=cut	906	=cut
…		…
862	if ($_[0] && $! == EXDEV) {	1028	if ($_[0] && $! == EXDEV) {
863	aioreq_pri $pri;	1029	aioreq_pri $pri;
864	add $grp aio_copy $src, $dst, sub {	1030	add $grp aio_copy $src, $dst, sub {
865	$grp->result ($_[0]);	1031	$grp->result ($_[0]);
866		1032
867	if (!$_[0]) {	1033	unless ($_[0]) {
868	aioreq_pri $pri;	1034	aioreq_pri $pri;
869	add $grp aio_unlink $src;	1035	add $grp aio_unlink $src;
870	}	1036	}
871	};	1037	};
872	} else {	1038	} else {
…		…
875	};	1041	};
876		1042
877	$grp	1043	$grp
878	}	1044	}
879		1045
880	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1046	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
881		1047
882	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1048	Scans a directory (similar to C<aio_readdir>) but additionally tries to
883	efficiently separate the entries of directory C<$path> into two sets of	1049	efficiently separate the entries of directory C<$path> into two sets of
884	names, directories you can recurse into (directories), and ones you cannot	1050	names, directories you can recurse into (directories), and ones you cannot
885	recurse into (everything else, including symlinks to directories).	1051	recurse into (everything else, including symlinks to directories).
…		…
916	Then entries will be sorted into likely directories a non-initial dot	1082	Then entries will be sorted into likely directories a non-initial dot
917	currently) and likely non-directories (see C<aio_readdirx>). Then every	1083	currently) and likely non-directories (see C<aio_readdirx>). Then every
918	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1084	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
919	in order of their inode numbers. If that succeeds, it assumes that the	1085	in order of their inode numbers. If that succeeds, it assumes that the
920	entry is a directory or a symlink to directory (which will be checked	1086	entry is a directory or a symlink to directory (which will be checked
921	seperately). This is often faster than stat'ing the entry itself because	1087	separately). This is often faster than stat'ing the entry itself because
922	filesystems might detect the type of the entry without reading the inode	1088	filesystems might detect the type of the entry without reading the inode
923	data (e.g. ext2fs filetype feature), even on systems that cannot return	1089	data (e.g. ext2fs filetype feature), even on systems that cannot return
924	the filetype information on readdir.	1090	the filetype information on readdir.
925		1091
926	If the known number of directories (link count - 2) has been reached, the	1092	If the known number of directories (link count - 2) has been reached, the
…		…
942		1108
943	my $grp = aio_group $cb;	1109	my $grp = aio_group $cb;
944		1110
945	$maxreq = 4 if $maxreq <= 0;	1111	$maxreq = 4 if $maxreq <= 0;
946		1112
947	# stat once	1113	# get a wd object
948	aioreq_pri $pri;	1114	aioreq_pri $pri;
949	add $grp aio_stat $path, sub {	1115	add $grp aio_wd $path, sub {
		1116	$_[0]
950	return $grp->result () if $_[0];	1117	or return $grp->result ();
951	my $now = time;
952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
953		1118
954	# read the directory entries	1119	my $wd = [shift, "."];
		1120
		1121	# stat once
955	aioreq_pri $pri;	1122	aioreq_pri $pri;
956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1123	add $grp aio_stat $wd, sub {
957	my $entries = shift
958	or return $grp->result ();	1124	return $grp->result () if $_[0];
		1125	my $now = time;
		1126	my $hash1 = join ":", (stat _)[0,1,3,7,9];
959		1127
960	# stat the dir another time	1128	# read the directory entries
961	aioreq_pri $pri;	1129	aioreq_pri $pri;
		1130	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1131	my $entries = shift
		1132	or return $grp->result ();
		1133
		1134	# stat the dir another time
		1135	aioreq_pri $pri;
962	add $grp aio_stat $path, sub {	1136	add $grp aio_stat $wd, sub {
963	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1137	my $hash2 = join ":", (stat _)[0,1,3,7,9];
964		1138
965	my $ndirs;	1139	my $ndirs;
966		1140
967	# take the slow route if anything looks fishy	1141	# take the slow route if anything looks fishy
968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1142	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
969	$ndirs = -1;	1143	$ndirs = -1;
970	} else {	1144	} else {
971	# if nlink == 2, we are finished	1145	# if nlink == 2, we are finished
972	# for non-posix-fs's, we rely on nlink < 2	1146	# for non-posix-fs's, we rely on nlink < 2
973	$ndirs = (stat _)[3] - 2	1147	$ndirs = (stat _)[3] - 2
974	or return $grp->result ([], $entries);	1148	or return $grp->result ([], $entries);
975	}	1149	}
976		1150
977	my (@dirs, @nondirs);	1151	my (@dirs, @nondirs);
978		1152
979	my $statgrp = add $grp aio_group sub {	1153	my $statgrp = add $grp aio_group sub {
980	$grp->result (\@dirs, \@nondirs);	1154	$grp->result (\@dirs, \@nondirs);
981	};	1155	};
982		1156
983	limit $statgrp $maxreq;	1157	limit $statgrp $maxreq;
984	feed $statgrp sub {	1158	feed $statgrp sub {
985	return unless @$entries;	1159	return unless @$entries;
986	my $entry = shift @$entries;	1160	my $entry = shift @$entries;
987		1161
988	aioreq_pri $pri;	1162	aioreq_pri $pri;
		1163	$wd->[1] = "$entry/.";
989	add $statgrp aio_stat "$path/$entry/.", sub {	1164	add $statgrp aio_stat $wd, sub {
990	if ($_[0] < 0) {	1165	if ($_[0] < 0) {
991	push @nondirs, $entry;	1166	push @nondirs, $entry;
992	} else {	1167	} else {
993	# need to check for real directory	1168	# need to check for real directory
994	aioreq_pri $pri;	1169	aioreq_pri $pri;
		1170	$wd->[1] = $entry;
995	add $statgrp aio_lstat "$path/$entry", sub {	1171	add $statgrp aio_lstat $wd, sub {
996	if (-d _) {	1172	if (-d _) {
997	push @dirs, $entry;	1173	push @dirs, $entry;
998		1174
999	unless (--$ndirs) {	1175	unless (--$ndirs) {
1000	push @nondirs, @$entries;	1176	push @nondirs, @$entries;
1001	feed $statgrp;	1177	feed $statgrp;
		1178	}
		1179	} else {
		1180	push @nondirs, $entry;
1002	}	1181	}
1003	} else {
1004	push @nondirs, $entry;
1005	}	1182	}
1006	}	1183	}
1007	}	1184	};
1008	};	1185	};
1009	};	1186	};
1010	};	1187	};
1011	};	1188	};
1012	};	1189	};
1013		1190
1014	$grp	1191	$grp
1015	}	1192	}
1016		1193
1017	=item aio_rmtree $path, $callback->($status)	1194	=item aio_rmtree $pathname, $callback->($status)
1018		1195
1019	Delete a directory tree starting (and including) C<$path>, return the	1196	Delete a directory tree starting (and including) C<$path>, return the
1020	status of the final C<rmdir> only. This is a composite request that	1197	status of the final C<rmdir> only. This is a composite request that
1021	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1198	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1022	everything else.	1199	everything else.
1023		1200
1024	=cut	1201	=cut
1025		1202
…		…
1064	callback with the fdatasync result code.	1241	callback with the fdatasync result code.
1065		1242
1066	If this call isn't available because your OS lacks it or it couldn't be	1243	If this call isn't available because your OS lacks it or it couldn't be
1067	detected, it will be emulated by calling C<fsync> instead.	1244	detected, it will be emulated by calling C<fsync> instead.
1068		1245
		1246	=item aio_syncfs $fh, $callback->($status)
		1247
		1248	Asynchronously call the syncfs syscall to sync the filesystem associated
		1249	to the given filehandle and call the callback with the syncfs result
		1250	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1251	errno to C<ENOSYS> nevertheless.
		1252
1069	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1253	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1070		1254
1071	Sync the data portion of the file specified by C<$offset> and C<$length>	1255	Sync the data portion of the file specified by C<$offset> and C<$length>
1072	to disk (but NOT the metadata), by calling the Linux-specific	1256	to disk (but NOT the metadata), by calling the Linux-specific
1073	sync_file_range call. If sync_file_range is not available or it returns	1257	sync_file_range call. If sync_file_range is not available or it returns
…		…
1076	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1260	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1077	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1261	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1078	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1262	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1079	manpage for details.	1263	manpage for details.
1080		1264
1081	=item aio_pathsync $path, $callback->($status)	1265	=item aio_pathsync $pathname, $callback->($status)
1082		1266
1083	This request tries to open, fsync and close the given path. This is a	1267	This request tries to open, fsync and close the given path. This is a
1084	composite request intended to sync directories after directory operations	1268	composite request intended to sync directories after directory operations
1085	(E.g. rename). This might not work on all operating systems or have any	1269	(E.g. rename). This might not work on all operating systems or have any
1086	specific effect, but usually it makes sure that directory changes get	1270	specific effect, but usually it makes sure that directory changes get
…		…
1138		1322
1139	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1323	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1140	scalars.	1324	scalars.
1141		1325
1142	It touches (reads or writes) all memory pages in the specified	1326	It touches (reads or writes) all memory pages in the specified
1143	range inside the scalar. All caveats and parameters are the same	1327	range inside the scalar. All caveats and parameters are the same
1144	as for C<aio_msync>, above, except for flags, which must be either	1328	as for C<aio_msync>, above, except for flags, which must be either
1145	C<0> (which reads all pages and ensures they are instantiated) or	1329	C<0> (which reads all pages and ensures they are instantiated) or
1146	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1330	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1147	writing an octet from it, which dirties the page).	1331	writing an octet from it, which dirties the page).
1148		1332
1149	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1333	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1150		1334
1151	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1335	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1182	documented under L<MISCELLANEOUS FUNCTIONS>.	1366	documented under L<MISCELLANEOUS FUNCTIONS>.
1183		1367
1184	Example: asynchronously lock all current and future pages into memory.	1368	Example: asynchronously lock all current and future pages into memory.
1185		1369
1186	aio_mlockall IO::AIO::MCL_FUTURE;	1370	aio_mlockall IO::AIO::MCL_FUTURE;
		1371
		1372	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1373
		1374	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1375	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1376	the ioctl is not available on your OS, then this request will fail with
		1377	C<ENOSYS>.
		1378
		1379	C<$start> is the starting offset to query extents for, C<$length> is the
		1380	size of the range to query - if it is C<undef>, then the whole file will
		1381	be queried.
		1382
		1383	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1384	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1385	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1386	the data portion.
		1387
		1388	C<$count> is the maximum number of extent records to return. If it is
		1389	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1390	case, if it is C<0>, then the callback receives the number of extents
		1391	instead of the extents themselves (which is unreliable, see below).
		1392
		1393	If an error occurs, the callback receives no arguments. The special
		1394	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1395
		1396	Otherwise, the callback receives an array reference with extent
		1397	structures. Each extent structure is an array reference itself, with the
		1398	following members:
		1399
		1400	[$logical, $physical, $length, $flags]
		1401
		1402	Flags is any combination of the following flag values (typically either C<0>
		1403	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1404
		1405	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1406	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1407	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1408	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1409	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1410	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1411
		1412	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1413	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1414	it to return all extents of a range for files with large number of
		1415	extents. The code works around all these issues if C<$count> is undef.
1187		1416
1188	=item aio_group $callback->(...)	1417	=item aio_group $callback->(...)
1189		1418
1190	This is a very special aio request: Instead of doing something, it is a	1419	This is a very special aio request: Instead of doing something, it is a
1191	container for other aio requests, which is useful if you want to bundle	1420	container for other aio requests, which is useful if you want to bundle
…		…
1228	like sleep and file handle readable/writable, the overhead this creates is	1457	like sleep and file handle readable/writable, the overhead this creates is
1229	immense (it blocks a thread for a long time) so do not use this function	1458	immense (it blocks a thread for a long time) so do not use this function
1230	except to put your application under artificial I/O pressure.	1459	except to put your application under artificial I/O pressure.
1231		1460
1232	=back	1461	=back
		1462
		1463
		1464	=head2 IO::AIO::WD - multiple working directories
		1465
		1466	Your process only has one current working directory, which is used by all
		1467	threads. This makes it hard to use relative paths (some other component
		1468	could call C<chdir> at any time, and it is hard to control when the path
		1469	will be used by IO::AIO).
		1470
		1471	One solution for this is to always use absolute paths. This usually works,
		1472	but can be quite slow (the kernel has to walk the whole path on every
		1473	access), and can also be a hassle to implement.
		1474
		1475	Newer POSIX systems have a number of functions (openat, fdopendir,
		1476	futimensat and so on) that make it possible to specify working directories
		1477	per operation.
		1478
		1479	For portability, and because the clowns who "designed", or shall I write,
		1480	perpetrated this new interface were obviously half-drunk, this abstraction
		1481	cannot be perfect, though.
		1482
		1483	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1484	object. This object stores the canonicalised, absolute version of the
		1485	path, and on systems that allow it, also a directory file descriptor.
		1486
		1487	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1488	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1489	object and a pathname instead (or the IO::AIO::WD object alone, which
		1490	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1491	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1492	to that IO::AIO::WD object.
		1493
		1494	For example, to get a wd object for F</etc> and then stat F<passwd>
		1495	inside, you would write:
		1496
		1497	aio_wd "/etc", sub {
		1498	my $etcdir = shift;
		1499
		1500	# although $etcdir can be undef on error, there is generally no reason
		1501	# to check for errors here, as aio_stat will fail with ENOENT
		1502	# when $etcdir is undef.
		1503
		1504	aio_stat [$etcdir, "passwd"], sub {
		1505	# yay
		1506	};
		1507	};
		1508
		1509	The fact that C<aio_wd> is a request and not a normal function shows that
		1510	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1511	which is why it is done asynchronously.
		1512
		1513	To stat the directory obtained with C<aio_wd> above, one could write
		1514	either of the following three request calls:
		1515
		1516	aio_lstat "/etc" , sub { ... # pathname as normal string
		1517	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1518	aio_lstat $wd , sub { ... # shorthand for the previous
		1519
		1520	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1521	object and the pathname string, so you could write the following without
		1522	causing any issues due to C<$path> getting reused:
		1523
		1524	my $path = [$wd, undef];
		1525
		1526	for my $name (qw(abc def ghi)) {
		1527	$path->[1] = $name;
		1528	aio_stat $path, sub {
		1529	# ...
		1530	};
		1531	}
		1532
		1533	There are some caveats: when directories get renamed (or deleted), the
		1534	pathname string doesn't change, so will point to the new directory (or
		1535	nowhere at all), while the directory fd, if available on the system,
		1536	will still point to the original directory. Most functions accepting a
		1537	pathname will use the directory fd on newer systems, and the string on
		1538	older systems. Some functions (such as realpath) will always rely on the
		1539	string form of the pathname.
		1540
		1541	So this functionality is mainly useful to get some protection against
		1542	C<chdir>, to easily get an absolute path out of a relative path for future
		1543	reference, and to speed up doing many operations in the same directory
		1544	(e.g. when stat'ing all files in a directory).
		1545
		1546	The following functions implement this working directory abstraction:
		1547
		1548	=over 4
		1549
		1550	=item aio_wd $pathname, $callback->($wd)
		1551
		1552	Asynchonously canonicalise the given pathname and convert it to an
		1553	IO::AIO::WD object representing it. If possible and supported on the
		1554	system, also open a directory fd to speed up pathname resolution relative
		1555	to this working directory.
		1556
		1557	If something goes wrong, then C<undef> is passwd to the callback instead
		1558	of a working directory object and C<$!> is set appropriately. Since
		1559	passing C<undef> as working directory component of a pathname fails the
		1560	request with C<ENOENT>, there is often no need for error checking in the
		1561	C<aio_wd> callback, as future requests using the value will fail in the
		1562	expected way.
		1563
		1564	=item IO::AIO::CWD
		1565
		1566	This is a compiletime constant (object) that represents the process
		1567	current working directory.
		1568
		1569	Specifying this object as working directory object for a pathname is as if
		1570	the pathname would be specified directly, without a directory object. For
		1571	example, these calls are functionally identical:
		1572
		1573	aio_stat "somefile", sub { ... };
		1574	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1575
		1576	=back
		1577
		1578	To recover the path associated with an IO::AIO::WD object, you can use
		1579	C<aio_realpath>:
		1580
		1581	aio_realpath $wd, sub {
		1582	warn "path is $_[0]\n";
		1583	};
		1584
		1585	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1586	sometimes, fall back to using an absolue path.
1233		1587
1234	=head2 IO::AIO::REQ CLASS	1588	=head2 IO::AIO::REQ CLASS
1235		1589
1236	All non-aggregate C<aio_*> functions return an object of this class when	1590	All non-aggregate C<aio_*> functions return an object of this class when
1237	called in non-void context.	1591	called in non-void context.
…		…
1355		1709
1356	Sets a feeder/generator on this group: every group can have an attached	1710	Sets a feeder/generator on this group: every group can have an attached
1357	generator that generates requests if idle. The idea behind this is that,	1711	generator that generates requests if idle. The idea behind this is that,
1358	although you could just queue as many requests as you want in a group,	1712	although you could just queue as many requests as you want in a group,
1359	this might starve other requests for a potentially long time. For example,	1713	this might starve other requests for a potentially long time. For example,
1360	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1714	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1361	delaying any later requests for a long time.	1715	requests, delaying any later requests for a long time.
1362		1716
1363	To avoid this, and allow incremental generation of requests, you can	1717	To avoid this, and allow incremental generation of requests, you can
1364	instead a group and set a feeder on it that generates those requests. The	1718	instead a group and set a feeder on it that generates those requests. The
1365	feed callback will be called whenever there are few enough (see C<limit>,	1719	feed callback will be called whenever there are few enough (see C<limit>,
1366	below) requests active in the group itself and is expected to queue more	1720	below) requests active in the group itself and is expected to queue more
…		…
1415		1769
1416	See C<poll_cb> for an example.	1770	See C<poll_cb> for an example.
1417		1771
1418	=item IO::AIO::poll_cb	1772	=item IO::AIO::poll_cb
1419		1773
1420	Process some outstanding events on the result pipe. You have to call	1774	Process some requests that have reached the result phase (i.e. they have
		1775	been executed but the results are not yet reported). You have to call
		1776	this "regularly" to finish outstanding requests.
		1777
1421	this regularly. Returns C<0> if all events could be processed (or there	1778	Returns C<0> if all events could be processed (or there were no
1422	were no events to process), or C<-1> if it returned earlier for whatever	1779	events to process), or C<-1> if it returned earlier for whatever
1423	reason. Returns immediately when no events are outstanding. The amount of	1780	reason. Returns immediately when no events are outstanding. The amount
1424	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1781	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1425	C<IO::AIO::max_poll_time>.	1782	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1426		1783
1427	If not all requests were processed for whatever reason, the filehandle	1784	If not all requests were processed for whatever reason, the poll file
1428	will still be ready when C<poll_cb> returns, so normally you don't have to	1785	descriptor will still be ready when C<poll_cb> returns, so normally you
1429	do anything special to have it called later.	1786	don't have to do anything special to have it called later.
1430		1787
1431	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1788	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1432	ready, it can be beneficial to call this function from loops which submit	1789	ready, it can be beneficial to call this function from loops which submit
1433	a lot of requests, to make sure the results get processed when they become	1790	a lot of requests, to make sure the results get processed when they become
1434	available and not just when the loop is finished and the event loop takes	1791	available and not just when the loop is finished and the event loop takes
…		…
1443	poll => 'r', async => 1,	1800	poll => 'r', async => 1,
1444	cb => \&IO::AIO::poll_cb);	1801	cb => \&IO::AIO::poll_cb);
1445		1802
1446	=item IO::AIO::poll_wait	1803	=item IO::AIO::poll_wait
1447		1804
1448	If there are any outstanding requests and none of them in the result	1805	Wait until either at least one request is in the result phase or no
1449	phase, wait till the result filehandle becomes ready for reading (simply	1806	requests are outstanding anymore.
1450	does a C<select> on the filehandle. This is useful if you want to	1807
1451	synchronously wait for some requests to finish).	1808	This is useful if you want to synchronously wait for some requests to
		1809	become ready, without actually handling them.
1452		1810
1453	See C<nreqs> for an example.	1811	See C<nreqs> for an example.
1454		1812
1455	=item IO::AIO::poll	1813	=item IO::AIO::poll
1456		1814
…		…
1577		1935
1578	This is a very bad function to use in interactive programs because it	1936	This is a very bad function to use in interactive programs because it
1579	blocks, and a bad way to reduce concurrency because it is inexact: Better	1937	blocks, and a bad way to reduce concurrency because it is inexact: Better
1580	use an C<aio_group> together with a feed callback.	1938	use an C<aio_group> together with a feed callback.
1581		1939
1582	It's main use is in scripts without an event loop - when you want to stat	1940	Its main use is in scripts without an event loop - when you want to stat
1583	a lot of files, you can write somehting like this:	1941	a lot of files, you can write somehting like this:
1584		1942
1585	IO::AIO::max_outstanding 32;	1943	IO::AIO::max_outstanding 32;
1586		1944
1587	for my $path (...) {	1945	for my $path (...) {
…		…
1627		1985
1628	=back	1986	=back
1629		1987
1630	=head3 MISCELLANEOUS FUNCTIONS	1988	=head3 MISCELLANEOUS FUNCTIONS
1631		1989
1632	IO::AIO implements some functions that might be useful, but are not	1990	IO::AIO implements some functions that are useful when you want to use
1633	asynchronous.	1991	some "Advanced I/O" function not available to in Perl, without going the
		1992	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		1993	counterpart.
1634		1994
1635	=over 4	1995	=over 4
1636		1996
1637	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	1997	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1638		1998
…		…
1645		2005
1646	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2006	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1647		2007
1648	Simply calls the C<posix_fadvise> function (see its	2008	Simply calls the C<posix_fadvise> function (see its
1649	manpage for details). The following advice constants are	2009	manpage for details). The following advice constants are
1650	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2010	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1651	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2011	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1652	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2012	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1653		2013
1654	On systems that do not implement C<posix_fadvise>, this function returns	2014	On systems that do not implement C<posix_fadvise>, this function returns
1655	ENOSYS, otherwise the return value of C<posix_fadvise>.	2015	ENOSYS, otherwise the return value of C<posix_fadvise>.
1656		2016
1657	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2017	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1658		2018
1659	Simply calls the C<posix_madvise> function (see its	2019	Simply calls the C<posix_madvise> function (see its
1660	manpage for details). The following advice constants are	2020	manpage for details). The following advice constants are
1661	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2021	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1662	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2022	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1663		2023
1664	On systems that do not implement C<posix_madvise>, this function returns	2024	On systems that do not implement C<posix_madvise>, this function returns
1665	ENOSYS, otherwise the return value of C<posix_madvise>.	2025	ENOSYS, otherwise the return value of C<posix_madvise>.
1666		2026
1667	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2027	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1668		2028
1669	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2029	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1670	$scalar (see its manpage for details). The following protect	2030	$scalar (see its manpage for details). The following protect
1671	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2031	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1672	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2032	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1673		2033
1674	On systems that do not implement C<mprotect>, this function returns	2034	On systems that do not implement C<mprotect>, this function returns
1675	ENOSYS, otherwise the return value of C<mprotect>.	2035	ENOSYS, otherwise the return value of C<mprotect>.
1676		2036
1677	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2037	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1678		2038
1679	Memory-maps a file (or anonymous memory range) and attaches it to the	2039	Memory-maps a file (or anonymous memory range) and attaches it to the
1680	given C<$scalar>, which will act like a string scalar.	2040	given C<$scalar>, which will act like a string scalar. Returns true on
		2041	success, and false otherwise.
1681		2042
1682	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2043	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1683	change the string length, and most read-only operations such as copying it	2044	change the string length, and most read-only operations such as copying it
1684	or searching it with regexes and so on.	2045	or searching it with regexes and so on.
1685		2046
…		…
1738	Calls the C<munlockall> function.	2099	Calls the C<munlockall> function.
1739		2100
1740	On systems that do not implement C<munlockall>, this function returns	2101	On systems that do not implement C<munlockall>, this function returns
1741	ENOSYS, otherwise the return value of C<munlockall>.	2102	ENOSYS, otherwise the return value of C<munlockall>.
1742		2103
		2104	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2105
		2106	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2107	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2108	should be the file offset.
		2109
		2110	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2111	silently corrupt the data in this case.
		2112
		2113	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2114	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2115	C<IO::AIO::SPLICE_F_GIFT>.
		2116
		2117	See the C<splice(2)> manpage for details.
		2118
		2119	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2120
		2121	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2122	description for C<IO::AIO::splice> above for details.
		2123
		2124	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2125
		2126	Attempts to query or change the pipe buffer size. Obviously works only
		2127	on pipes, and currently works only on GNU/Linux systems, and fails with
		2128	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2129	size on other systems, drop me a note.
		2130
		2131	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2132
		2133	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2134	C<$flags> is missing or C<0>, then this should be the same as a call to
		2135	perl's built-in C<pipe> function and create a new pipe, and works on
		2136	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2137	(..., 4096, O_BINARY)>.
		2138
		2139	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2140	the given flags (Linux 2.6.27, glibc 2.9).
		2141
		2142	On success, the read and write file handles are returned.
		2143
		2144	On error, nothing will be returned. If the pipe2 syscall is missing and
		2145	C<$flags> is non-zero, fails with C<ENOSYS>.
		2146
		2147	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2148	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2149	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2150
1743	=back	2151	=back
1744		2152
1745	=cut	2153	=cut
1746		2154
1747	min_parallel 8;	2155	min_parallel 8;
…		…
1781	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2189	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1782	\&IO::AIO::poll_cb);	2190	\&IO::AIO::poll_cb);
1783		2191
1784	=head2 FORK BEHAVIOUR	2192	=head2 FORK BEHAVIOUR
1785		2193
1786	This module should do "the right thing" when the process using it forks:	2194	Usage of pthreads in a program changes the semantics of fork
		2195	considerably. Specifically, only async-safe functions can be called after
		2196	fork. Perl doesn't know about this, so in general, you cannot call fork
		2197	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2198	pthreads, so this applies, but many other extensions and (for inexplicable
		2199	reasons) perl itself often is linked against pthreads, so this limitation
		2200	applies to quite a lot of perls.
1787		2201
1788	Before the fork, IO::AIO enters a quiescent state where no requests	2202	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1789	can be added in other threads and no results will be processed. After	2203	only works in the process that loaded it. Forking is fully supported, but
1790	the fork the parent simply leaves the quiescent state and continues	2204	using IO::AIO in the child is not.
1791	request/result processing, while the child frees the request/result queue
1792	(so that the requests started before the fork will only be handled in the
1793	parent). Threads will be started on demand until the limit set in the
1794	parent process has been reached again.
1795		2205
1796	In short: the parent will, after a short pause, continue as if fork had	2206	You might get around by not I<using> IO::AIO before (or after)
1797	not been called, while the child will act as if IO::AIO has not been used	2207	forking. You could also try to call the L<IO::AIO::reinit> function in the
1798	yet.	2208	child:
		2209
		2210	=over 4
		2211
		2212	=item IO::AIO::reinit
		2213
		2214	Abandons all current requests and I/O threads and simply reinitialises all
		2215	data structures. This is not an operation supported by any standards, but
		2216	happens to work on GNU/Linux and some newer BSD systems.
		2217
		2218	The only reasonable use for this function is to call it after forking, if
		2219	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2220	the process will result in undefined behaviour. Calling it at any time
		2221	will also result in any undefined (by POSIX) behaviour.
		2222
		2223	=back
1799		2224
1800	=head2 MEMORY USAGE	2225	=head2 MEMORY USAGE
1801		2226
1802	Per-request usage:	2227	Per-request usage:
1803		2228

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC vs. Revision 1.254 by root, Thu Jun 25 13:42:18 2015 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC vs.
Revision 1.254 by root, Thu Jun 25 13:42:18 2015 UTC