[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 1.247 by root, Tue Jun 3 01:30:33 2014 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 = 4.31;
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, $callback->($link)
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 freed disk space according to the C<$mode> argument. See the
		728	linux C<fallocate> docuemntation for details.
		729
		730	C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
		731	to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \|
		732	IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
		733
		734	The file system block size used by C<fallocate> is presumably the
		735	C<f_bsize> returned by C<statvfs>.
		736
		737	If C<fallocate> isn't available or cannot be emulated (currently no
		738	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		739
		740
597	=item aio_chmod $fh_or_path, $mode, $callback->($status)	741	=item aio_chmod $fh_or_path, $mode, $callback->($status)
598		742
599	Works like perl's C<chmod> function.	743	Works like perl's C<chmod> function.
600		744
601		745
…		…
603		747
604	Asynchronously unlink (delete) a file and call the callback with the	748	Asynchronously unlink (delete) a file and call the callback with the
605	result code.	749	result code.
606		750
607		751
608	=item aio_mknod $path, $mode, $dev, $callback->($status)	752	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
609		753
610	[EXPERIMENTAL]	754	[EXPERIMENTAL]
611		755
612	Asynchronously create a device node (or fifo). See mknod(2).	756	Asynchronously create a device node (or fifo). See mknod(2).
613		757
614	The only (POSIX-) portable way of calling this function is:	758	The only (POSIX-) portable way of calling this function is:
615		759
616	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	760	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
617		761
618	See C<aio_stat> for info about some potentially helpful extra constants	762	See C<aio_stat> for info about some potentially helpful extra constants
619	and functions.	763	and functions.
620		764
621	=item aio_link $srcpath, $dstpath, $callback->($status)	765	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
628		772
629	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	773	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
630	the path C<$dstpath> and call the callback with the result code.	774	the path C<$dstpath> and call the callback with the result code.
631		775
632		776
633	=item aio_readlink $path, $callback->($link)	777	=item aio_readlink $pathname, $callback->($link)
634		778
635	Asynchronously read the symlink specified by C<$path> and pass it to	779	Asynchronously read the symlink specified by C<$path> and pass it to
636	the callback. If an error occurs, nothing or undef gets passed to the	780	the callback. If an error occurs, nothing or undef gets passed to the
637	callback.	781	callback.
638		782
639		783
		784	=item aio_realpath $pathname, $callback->($path)
		785
		786	Asynchronously make the path absolute and resolve any symlinks in
		787	C<$path>. The resulting path only consists of directories (same as
		788	L<Cwd::realpath>).
		789
		790	This request can be used to get the absolute path of the current working
		791	directory by passing it a path of F<.> (a single dot).
		792
		793
640	=item aio_rename $srcpath, $dstpath, $callback->($status)	794	=item aio_rename $srcpath, $dstpath, $callback->($status)
641		795
642	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	796	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
643	rename(2) and call the callback with the result code.	797	rename(2) and call the callback with the result code.
		798
		799	On systems that support the AIO::WD working directory abstraction
		800	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		801	of failing, C<rename> is called on the absolute path of C<$wd>.
644		802
645		803
646	=item aio_mkdir $pathname, $mode, $callback->($status)	804	=item aio_mkdir $pathname, $mode, $callback->($status)
647		805
648	Asynchronously mkdir (create) a directory and call the callback with	806	Asynchronously mkdir (create) a directory and call the callback with
…		…
653	=item aio_rmdir $pathname, $callback->($status)	811	=item aio_rmdir $pathname, $callback->($status)
654		812
655	Asynchronously rmdir (delete) a directory and call the callback with the	813	Asynchronously rmdir (delete) a directory and call the callback with the
656	result code.	814	result code.
657		815
		816	On systems that support the AIO::WD working directory abstraction
		817	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		818	C<rmdir> is called on the absolute path of C<$wd>.
		819
658		820
659	=item aio_readdir $pathname, $callback->($entries)	821	=item aio_readdir $pathname, $callback->($entries)
660		822
661	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	823	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	824	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
666	array-ref with the filenames.	828	array-ref with the filenames.
667		829
668		830
669	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	831	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
670		832
671	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	833	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	834	tune behaviour and output format. In case of an error, C<$entries> will be
673	C<undef>.	835	C<undef>.
674		836
675	The flags are a combination of the following constants, ORed together (the	837	The flags are a combination of the following constants, ORed together (the
676	flags will also be passed to the callback, possibly modified):	838	flags will also be passed to the callback, possibly modified):
677		839
…		…
724		886
725	=item IO::AIO::READDIR_FOUND_UNKNOWN	887	=item IO::AIO::READDIR_FOUND_UNKNOWN
726		888
727	This flag should not be set when calling C<aio_readdirx>. Instead, it	889	This flag should not be set when calling C<aio_readdirx>. Instead, it
728	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	890	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
729	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	891	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
730	C<$type>'s are known, which can be used to speed up some algorithms.	892	C<$type>'s are known, which can be used to speed up some algorithms.
731		893
732	=back	894	=back
733		895
734		896
735	=item aio_load $path, $data, $callback->($status)	897	=item aio_load $pathname, $data, $callback->($status)
736		898
737	This is a composite request that tries to fully load the given file into	899	This is a composite request that tries to fully load the given file into
738	memory. Status is the same as with aio_read.	900	memory. Status is the same as with aio_read.
739		901
740	=cut	902	=cut
…		…
862	if ($_[0] && $! == EXDEV) {	1024	if ($_[0] && $! == EXDEV) {
863	aioreq_pri $pri;	1025	aioreq_pri $pri;
864	add $grp aio_copy $src, $dst, sub {	1026	add $grp aio_copy $src, $dst, sub {
865	$grp->result ($_[0]);	1027	$grp->result ($_[0]);
866		1028
867	if (!$_[0]) {	1029	unless ($_[0]) {
868	aioreq_pri $pri;	1030	aioreq_pri $pri;
869	add $grp aio_unlink $src;	1031	add $grp aio_unlink $src;
870	}	1032	}
871	};	1033	};
872	} else {	1034	} else {
…		…
875	};	1037	};
876		1038
877	$grp	1039	$grp
878	}	1040	}
879		1041
880	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1042	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
881		1043
882	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1044	Scans a directory (similar to C<aio_readdir>) but additionally tries to
883	efficiently separate the entries of directory C<$path> into two sets of	1045	efficiently separate the entries of directory C<$path> into two sets of
884	names, directories you can recurse into (directories), and ones you cannot	1046	names, directories you can recurse into (directories), and ones you cannot
885	recurse into (everything else, including symlinks to directories).	1047	recurse into (everything else, including symlinks to directories).
…		…
916	Then entries will be sorted into likely directories a non-initial dot	1078	Then entries will be sorted into likely directories a non-initial dot
917	currently) and likely non-directories (see C<aio_readdirx>). Then every	1079	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,	1080	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	1081	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	1082	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	1083	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	1084	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	1085	data (e.g. ext2fs filetype feature), even on systems that cannot return
924	the filetype information on readdir.	1086	the filetype information on readdir.
925		1087
926	If the known number of directories (link count - 2) has been reached, the	1088	If the known number of directories (link count - 2) has been reached, the
…		…
942		1104
943	my $grp = aio_group $cb;	1105	my $grp = aio_group $cb;
944		1106
945	$maxreq = 4 if $maxreq <= 0;	1107	$maxreq = 4 if $maxreq <= 0;
946		1108
947	# stat once	1109	# get a wd object
948	aioreq_pri $pri;	1110	aioreq_pri $pri;
949	add $grp aio_stat $path, sub {	1111	add $grp aio_wd $path, sub {
		1112	$_[0]
950	return $grp->result () if $_[0];	1113	or return $grp->result ();
951	my $now = time;
952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
953		1114
954	# read the directory entries	1115	my $wd = [shift, "."];
		1116
		1117	# stat once
955	aioreq_pri $pri;	1118	aioreq_pri $pri;
956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1119	add $grp aio_stat $wd, sub {
957	my $entries = shift
958	or return $grp->result ();	1120	return $grp->result () if $_[0];
		1121	my $now = time;
		1122	my $hash1 = join ":", (stat _)[0,1,3,7,9];
959		1123
960	# stat the dir another time	1124	# read the directory entries
961	aioreq_pri $pri;	1125	aioreq_pri $pri;
		1126	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1127	my $entries = shift
		1128	or return $grp->result ();
		1129
		1130	# stat the dir another time
		1131	aioreq_pri $pri;
962	add $grp aio_stat $path, sub {	1132	add $grp aio_stat $wd, sub {
963	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1133	my $hash2 = join ":", (stat _)[0,1,3,7,9];
964		1134
965	my $ndirs;	1135	my $ndirs;
966		1136
967	# take the slow route if anything looks fishy	1137	# take the slow route if anything looks fishy
968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1138	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
969	$ndirs = -1;	1139	$ndirs = -1;
970	} else {	1140	} else {
971	# if nlink == 2, we are finished	1141	# if nlink == 2, we are finished
972	# for non-posix-fs's, we rely on nlink < 2	1142	# for non-posix-fs's, we rely on nlink < 2
973	$ndirs = (stat _)[3] - 2	1143	$ndirs = (stat _)[3] - 2
974	or return $grp->result ([], $entries);	1144	or return $grp->result ([], $entries);
975	}	1145	}
976		1146
977	my (@dirs, @nondirs);	1147	my (@dirs, @nondirs);
978		1148
979	my $statgrp = add $grp aio_group sub {	1149	my $statgrp = add $grp aio_group sub {
980	$grp->result (\@dirs, \@nondirs);	1150	$grp->result (\@dirs, \@nondirs);
981	};	1151	};
982		1152
983	limit $statgrp $maxreq;	1153	limit $statgrp $maxreq;
984	feed $statgrp sub {	1154	feed $statgrp sub {
985	return unless @$entries;	1155	return unless @$entries;
986	my $entry = shift @$entries;	1156	my $entry = shift @$entries;
987		1157
988	aioreq_pri $pri;	1158	aioreq_pri $pri;
		1159	$wd->[1] = "$entry/.";
989	add $statgrp aio_stat "$path/$entry/.", sub {	1160	add $statgrp aio_stat $wd, sub {
990	if ($_[0] < 0) {	1161	if ($_[0] < 0) {
991	push @nondirs, $entry;	1162	push @nondirs, $entry;
992	} else {	1163	} else {
993	# need to check for real directory	1164	# need to check for real directory
994	aioreq_pri $pri;	1165	aioreq_pri $pri;
		1166	$wd->[1] = $entry;
995	add $statgrp aio_lstat "$path/$entry", sub {	1167	add $statgrp aio_lstat $wd, sub {
996	if (-d _) {	1168	if (-d _) {
997	push @dirs, $entry;	1169	push @dirs, $entry;
998		1170
999	unless (--$ndirs) {	1171	unless (--$ndirs) {
1000	push @nondirs, @$entries;	1172	push @nondirs, @$entries;
1001	feed $statgrp;	1173	feed $statgrp;
		1174	}
		1175	} else {
		1176	push @nondirs, $entry;
1002	}	1177	}
1003	} else {
1004	push @nondirs, $entry;
1005	}	1178	}
1006	}	1179	}
1007	}	1180	};
1008	};	1181	};
1009	};	1182	};
1010	};	1183	};
1011	};	1184	};
1012	};	1185	};
1013		1186
1014	$grp	1187	$grp
1015	}	1188	}
1016		1189
1017	=item aio_rmtree $path, $callback->($status)	1190	=item aio_rmtree $pathname, $callback->($status)
1018		1191
1019	Delete a directory tree starting (and including) C<$path>, return the	1192	Delete a directory tree starting (and including) C<$path>, return the
1020	status of the final C<rmdir> only. This is a composite request that	1193	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	1194	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1022	everything else.	1195	everything else.
1023		1196
1024	=cut	1197	=cut
1025		1198
…		…
1064	callback with the fdatasync result code.	1237	callback with the fdatasync result code.
1065		1238
1066	If this call isn't available because your OS lacks it or it couldn't be	1239	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.	1240	detected, it will be emulated by calling C<fsync> instead.
1068		1241
		1242	=item aio_syncfs $fh, $callback->($status)
		1243
		1244	Asynchronously call the syncfs syscall to sync the filesystem associated
		1245	to the given filehandle and call the callback with the syncfs result
		1246	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1247	errno to C<ENOSYS> nevertheless.
		1248
1069	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1249	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1070		1250
1071	Sync the data portion of the file specified by C<$offset> and C<$length>	1251	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	1252	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	1253	sync_file_range call. If sync_file_range is not available or it returns
…		…
1076	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1256	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1077	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1257	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1078	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1258	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1079	manpage for details.	1259	manpage for details.
1080		1260
1081	=item aio_pathsync $path, $callback->($status)	1261	=item aio_pathsync $pathname, $callback->($status)
1082		1262
1083	This request tries to open, fsync and close the given path. This is a	1263	This request tries to open, fsync and close the given path. This is a
1084	composite request intended to sync directories after directory operations	1264	composite request intended to sync directories after directory operations
1085	(E.g. rename). This might not work on all operating systems or have any	1265	(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	1266	specific effect, but usually it makes sure that directory changes get
…		…
1138		1318
1139	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1319	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1140	scalars.	1320	scalars.
1141		1321
1142	It touches (reads or writes) all memory pages in the specified	1322	It touches (reads or writes) all memory pages in the specified
1143	range inside the scalar. All caveats and parameters are the same	1323	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	1324	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	1325	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	1326	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1147	writing an octet from it, which dirties the page).	1327	writing an octet from it, which dirties the page).
1148		1328
1149	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1329	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1150		1330
1151	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1331	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1182	documented under L<MISCELLANEOUS FUNCTIONS>.	1362	documented under L<MISCELLANEOUS FUNCTIONS>.
1183		1363
1184	Example: asynchronously lock all current and future pages into memory.	1364	Example: asynchronously lock all current and future pages into memory.
1185		1365
1186	aio_mlockall IO::AIO::MCL_FUTURE;	1366	aio_mlockall IO::AIO::MCL_FUTURE;
		1367
		1368	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1369
		1370	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1371	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1372	the ioctl is not available on your OS, then this request will fail with
		1373	C<ENOSYS>.
		1374
		1375	C<$start> is the starting offset to query extents for, C<$length> is the
		1376	size of the range to query - if it is C<undef>, then the whole file will
		1377	be queried.
		1378
		1379	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1380	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1381	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1382	the data portion.
		1383
		1384	C<$count> is the maximum number of extent records to return. If it is
		1385	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1386	case, if it is C<0>, then the callback receives the number of extents
		1387	instead of the extents themselves (which is unreliable, see below).
		1388
		1389	If an error occurs, the callback receives no arguments. The special
		1390	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1391
		1392	Otherwise, the callback receives an array reference with extent
		1393	structures. Each extent structure is an array reference itself, with the
		1394	following members:
		1395
		1396	[$logical, $physical, $length, $flags]
		1397
		1398	Flags is any combination of the following flag values (typically either C<0>
		1399	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1400
		1401	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1402	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1403	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1404	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1405	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1406	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1407
		1408	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1409	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1410	it to return all extents of a range for files with large number of
		1411	extents. The code works around all these issues if C<$count> is undef.
1187		1412
1188	=item aio_group $callback->(...)	1413	=item aio_group $callback->(...)
1189		1414
1190	This is a very special aio request: Instead of doing something, it is a	1415	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	1416	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	1453	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	1454	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.	1455	except to put your application under artificial I/O pressure.
1231		1456
1232	=back	1457	=back
		1458
		1459
		1460	=head2 IO::AIO::WD - multiple working directories
		1461
		1462	Your process only has one current working directory, which is used by all
		1463	threads. This makes it hard to use relative paths (some other component
		1464	could call C<chdir> at any time, and it is hard to control when the path
		1465	will be used by IO::AIO).
		1466
		1467	One solution for this is to always use absolute paths. This usually works,
		1468	but can be quite slow (the kernel has to walk the whole path on every
		1469	access), and can also be a hassle to implement.
		1470
		1471	Newer POSIX systems have a number of functions (openat, fdopendir,
		1472	futimensat and so on) that make it possible to specify working directories
		1473	per operation.
		1474
		1475	For portability, and because the clowns who "designed", or shall I write,
		1476	perpetrated this new interface were obviously half-drunk, this abstraction
		1477	cannot be perfect, though.
		1478
		1479	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1480	object. This object stores the canonicalised, absolute version of the
		1481	path, and on systems that allow it, also a directory file descriptor.
		1482
		1483	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1484	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1485	object and a pathname instead (or the IO::AIO::WD object alone, which
		1486	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1487	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1488	to that IO::AIO::WD object.
		1489
		1490	For example, to get a wd object for F</etc> and then stat F<passwd>
		1491	inside, you would write:
		1492
		1493	aio_wd "/etc", sub {
		1494	my $etcdir = shift;
		1495
		1496	# although $etcdir can be undef on error, there is generally no reason
		1497	# to check for errors here, as aio_stat will fail with ENOENT
		1498	# when $etcdir is undef.
		1499
		1500	aio_stat [$etcdir, "passwd"], sub {
		1501	# yay
		1502	};
		1503	};
		1504
		1505	That C<aio_wd> is a request and not a normal function shows that creating
		1506	an IO::AIO::WD object is itself a potentially blocking operation, which is
		1507	why it is done asynchronously.
		1508
		1509	To stat the directory obtained with C<aio_wd> above, one could write
		1510	either of the following three request calls:
		1511
		1512	aio_lstat "/etc" , sub { ... # pathname as normal string
		1513	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1514	aio_lstat $wd , sub { ... # shorthand for the previous
		1515
		1516	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1517	object and the pathname string, so you could write the following without
		1518	causing any issues due to C<$path> getting reused:
		1519
		1520	my $path = [$wd, undef];
		1521
		1522	for my $name (qw(abc def ghi)) {
		1523	$path->[1] = $name;
		1524	aio_stat $path, sub {
		1525	# ...
		1526	};
		1527	}
		1528
		1529	There are some caveats: when directories get renamed (or deleted), the
		1530	pathname string doesn't change, so will point to the new directory (or
		1531	nowhere at all), while the directory fd, if available on the system,
		1532	will still point to the original directory. Most functions accepting a
		1533	pathname will use the directory fd on newer systems, and the string on
		1534	older systems. Some functions (such as realpath) will always rely on the
		1535	string form of the pathname.
		1536
		1537	So this functionality is mainly useful to get some protection against
		1538	C<chdir>, to easily get an absolute path out of a relative path for future
		1539	reference, and to speed up doing many operations in the same directory
		1540	(e.g. when stat'ing all files in a directory).
		1541
		1542	The following functions implement this working directory abstraction:
		1543
		1544	=over 4
		1545
		1546	=item aio_wd $pathname, $callback->($wd)
		1547
		1548	Asynchonously canonicalise the given pathname and convert it to an
		1549	IO::AIO::WD object representing it. If possible and supported on the
		1550	system, also open a directory fd to speed up pathname resolution relative
		1551	to this working directory.
		1552
		1553	If something goes wrong, then C<undef> is passwd to the callback instead
		1554	of a working directory object and C<$!> is set appropriately. Since
		1555	passing C<undef> as working directory component of a pathname fails the
		1556	request with C<ENOENT>, there is often no need for error checking in the
		1557	C<aio_wd> callback, as future requests using the value will fail in the
		1558	expected way.
		1559
		1560	=item IO::AIO::CWD
		1561
		1562	This is a compiletime constant (object) that represents the process
		1563	current working directory.
		1564
		1565	Specifying this object as working directory object for a pathname is as if
		1566	the pathname would be specified directly, without a directory object. For
		1567	example, these calls are functionally identical:
		1568
		1569	aio_stat "somefile", sub { ... };
		1570	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1571
		1572	=back
		1573
		1574	To recover the path associated with an IO::AIO::WD object, you can use
		1575	C<aio_realpath>:
		1576
		1577	aio_realpath $wd, sub {
		1578	warn "path is $_[0]\n";
		1579	};
		1580
		1581	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1582	sometimes, fall back to using an absolue path.
1233		1583
1234	=head2 IO::AIO::REQ CLASS	1584	=head2 IO::AIO::REQ CLASS
1235		1585
1236	All non-aggregate C<aio_*> functions return an object of this class when	1586	All non-aggregate C<aio_*> functions return an object of this class when
1237	called in non-void context.	1587	called in non-void context.
…		…
1355		1705
1356	Sets a feeder/generator on this group: every group can have an attached	1706	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,	1707	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,	1708	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,	1709	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,	1710	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1361	delaying any later requests for a long time.	1711	requests, delaying any later requests for a long time.
1362		1712
1363	To avoid this, and allow incremental generation of requests, you can	1713	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	1714	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>,	1715	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	1716	below) requests active in the group itself and is expected to queue more
…		…
1415		1765
1416	See C<poll_cb> for an example.	1766	See C<poll_cb> for an example.
1417		1767
1418	=item IO::AIO::poll_cb	1768	=item IO::AIO::poll_cb
1419		1769
1420	Process some outstanding events on the result pipe. You have to call	1770	Process some requests that have reached the result phase (i.e. they have
		1771	been executed but the results are not yet reported). You have to call
		1772	this "regularly" to finish outstanding requests.
		1773
1421	this regularly. Returns C<0> if all events could be processed (or there	1774	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	1775	events to process), or C<-1> if it returned earlier for whatever
1423	reason. Returns immediately when no events are outstanding. The amount of	1776	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	1777	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1425	C<IO::AIO::max_poll_time>.	1778	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1426		1779
1427	If not all requests were processed for whatever reason, the filehandle	1780	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	1781	descriptor will still be ready when C<poll_cb> returns, so normally you
1429	do anything special to have it called later.	1782	don't have to do anything special to have it called later.
1430		1783
1431	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1784	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	1785	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	1786	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	1787	available and not just when the loop is finished and the event loop takes
…		…
1443	poll => 'r', async => 1,	1796	poll => 'r', async => 1,
1444	cb => \&IO::AIO::poll_cb);	1797	cb => \&IO::AIO::poll_cb);
1445		1798
1446	=item IO::AIO::poll_wait	1799	=item IO::AIO::poll_wait
1447		1800
1448	If there are any outstanding requests and none of them in the result	1801	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	1802	requests are outstanding anymore.
1450	does a C<select> on the filehandle. This is useful if you want to	1803
1451	synchronously wait for some requests to finish).	1804	This is useful if you want to synchronously wait for some requests to
		1805	become ready, without actually handling them.
1452		1806
1453	See C<nreqs> for an example.	1807	See C<nreqs> for an example.
1454		1808
1455	=item IO::AIO::poll	1809	=item IO::AIO::poll
1456		1810
…		…
1645		1999
1646	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2000	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1647		2001
1648	Simply calls the C<posix_fadvise> function (see its	2002	Simply calls the C<posix_fadvise> function (see its
1649	manpage for details). The following advice constants are	2003	manpage for details). The following advice constants are
1650	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2004	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1651	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2005	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1652	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2006	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1653		2007
1654	On systems that do not implement C<posix_fadvise>, this function returns	2008	On systems that do not implement C<posix_fadvise>, this function returns
1655	ENOSYS, otherwise the return value of C<posix_fadvise>.	2009	ENOSYS, otherwise the return value of C<posix_fadvise>.
1656		2010
1657	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2011	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1658		2012
1659	Simply calls the C<posix_madvise> function (see its	2013	Simply calls the C<posix_madvise> function (see its
1660	manpage for details). The following advice constants are	2014	manpage for details). The following advice constants are
1661	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2015	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>.	2016	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1663		2017
1664	On systems that do not implement C<posix_madvise>, this function returns	2018	On systems that do not implement C<posix_madvise>, this function returns
1665	ENOSYS, otherwise the return value of C<posix_madvise>.	2019	ENOSYS, otherwise the return value of C<posix_madvise>.
1666		2020
1667	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2021	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1668		2022
1669	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2023	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1670	$scalar (see its manpage for details). The following protect	2024	$scalar (see its manpage for details). The following protect
1671	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2025	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1672	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2026	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1673		2027
1674	On systems that do not implement C<mprotect>, this function returns	2028	On systems that do not implement C<mprotect>, this function returns
1675	ENOSYS, otherwise the return value of C<mprotect>.	2029	ENOSYS, otherwise the return value of C<mprotect>.
1676		2030
1677	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2031	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1678		2032
1679	Memory-maps a file (or anonymous memory range) and attaches it to the	2033	Memory-maps a file (or anonymous memory range) and attaches it to the
1680	given C<$scalar>, which will act like a string scalar.	2034	given C<$scalar>, which will act like a string scalar. Returns true on
		2035	success, and false otherwise.
1681		2036
1682	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2037	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	2038	change the string length, and most read-only operations such as copying it
1684	or searching it with regexes and so on.	2039	or searching it with regexes and so on.
1685		2040
…		…
1738	Calls the C<munlockall> function.	2093	Calls the C<munlockall> function.
1739		2094
1740	On systems that do not implement C<munlockall>, this function returns	2095	On systems that do not implement C<munlockall>, this function returns
1741	ENOSYS, otherwise the return value of C<munlockall>.	2096	ENOSYS, otherwise the return value of C<munlockall>.
1742		2097
		2098	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2099
		2100	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2101	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2102	should be the file offset.
		2103
		2104	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2105	silently corrupt the data in this case.
		2106
		2107	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2108	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2109	C<IO::AIO::SPLICE_F_GIFT>.
		2110
		2111	See the C<splice(2)> manpage for details.
		2112
		2113	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2114
		2115	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
		2116	description for C<IO::AIO::splice> above for details.
		2117
		2118	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2119
		2120	Attempts to query or change the pipe buffer size. Obviously works only
		2121	on pipes, and currently works only on GNU/Linux systems, and fails with
		2122	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2123	size on other systems, drop me a note.
		2124
1743	=back	2125	=back
1744		2126
1745	=cut	2127	=cut
1746		2128
1747	min_parallel 8;	2129	min_parallel 8;
…		…
1781	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2163	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1782	\&IO::AIO::poll_cb);	2164	\&IO::AIO::poll_cb);
1783		2165
1784	=head2 FORK BEHAVIOUR	2166	=head2 FORK BEHAVIOUR
1785		2167
1786	This module should do "the right thing" when the process using it forks:	2168	Usage of pthreads in a program changes the semantics of fork
		2169	considerably. Specifically, only async-safe functions can be called after
		2170	fork. Perl doesn't know about this, so in general, you cannot call fork
		2171	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2172	pthreads, so this applies, but many other extensions and (for inexplicable
		2173	reasons) perl itself often is linked against pthreads, so this limitation
		2174	applies to quite a lot of perls.
1787		2175
1788	Before the fork, IO::AIO enters a quiescent state where no requests	2176	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	2177	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	2178	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		2179
1796	In short: the parent will, after a short pause, continue as if fork had	2180	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	2181	forking. You could also try to call the L<IO::AIO::reinit> function in the
1798	yet.	2182	child:
		2183
		2184	=over 4
		2185
		2186	=item IO::AIO::reinit
		2187
		2188	Abandons all current requests and I/O threads and simply reinitialises all
		2189	data structures. This is not an operation supported by any standards, but
		2190	happens to work on GNU/Linux and some newer BSD systems.
		2191
		2192	The only reasonable use for this function is to call it after forking, if
		2193	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2194	the process will result in undefined behaviour. Calling it at any time
		2195	will also result in any undefined (by POSIX) behaviour.
		2196
		2197	=back
1799		2198
1800	=head2 MEMORY USAGE	2199	=head2 MEMORY USAGE
1801		2200
1802	Per-request usage:	2201	Per-request usage:
1803		2202

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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 1.247 by root, Tue Jun 3 01:30:33 2014 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 1.247 by root, Tue Jun 3 01:30:33 2014 UTC