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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.194 by root, Fri May 27 00:44:49 2011 UTC vs.
Revision 1.241 by root, Fri Dec 28 07:33:41 2012 UTC

…		…
168	use common::sense;	168	use common::sense;
169		169
170	use base 'Exporter';	170	use base 'Exporter';
171		171
172	BEGIN {	172	BEGIN {
173	our $VERSION = '3.9';	173	our $VERSION = '4.18';
174		174
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	175	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	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
		179	aio_pathsync aio_readahead aio_fiemap
179	aio_rename aio_link aio_move aio_copy aio_group	180	aio_rename aio_link aio_move aio_copy aio_group
180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181	aio_chmod aio_utime aio_truncate	182	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_mlock aio_mlockall	183	aio_msync aio_mtouch aio_mlock aio_mlockall
183	aio_statvfs);	184	aio_statvfs
		185	aio_wd);
184		186
185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
187	min_parallel max_parallel max_idle idle_timeout	189	min_parallel max_parallel max_idle idle_timeout
188	nreqs nready npending nthreads	190	nreqs nready npending nthreads
…		…
200		202
201	=head1 FUNCTIONS	203	=head1 FUNCTIONS
202		204
203	=head2 QUICK OVERVIEW	205	=head2 QUICK OVERVIEW
204		206
205	This section simply lists the prototypes of the most important functions	207	This section simply lists the prototypes most of the functions for
206	for quick reference. See the following sections for function-by-function	208	quick reference. See the following sections for function-by-function
207	documentation.	209	documentation.
208		210
		211	aio_wd $pathname, $callback->($wd)
209	aio_open $pathname, $flags, $mode, $callback->($fh)	212	aio_open $pathname, $flags, $mode, $callback->($fh)
210	aio_close $fh, $callback->($status)	213	aio_close $fh, $callback->($status)
		214	aio_seek $fh,$offset,$whence, $callback->($offs)
211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	216	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	217	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214	aio_readahead $fh,$offset,$length, $callback->($retval)	218	aio_readahead $fh,$offset,$length, $callback->($retval)
215	aio_stat $fh_or_path, $callback->($status)	219	aio_stat $fh_or_path, $callback->($status)
216	aio_lstat $fh, $callback->($status)	220	aio_lstat $fh, $callback->($status)
217	aio_statvfs $fh_or_path, $callback->($statvfs)	221	aio_statvfs $fh_or_path, $callback->($statvfs)
218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	222	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	223	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		224	aio_chmod $fh_or_path, $mode, $callback->($status)
220	aio_truncate $fh_or_path, $offset, $callback->($status)	225	aio_truncate $fh_or_path, $offset, $callback->($status)
221	aio_chmod $fh_or_path, $mode, $callback->($status)	226	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		227	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
222	aio_unlink $pathname, $callback->($status)	228	aio_unlink $pathname, $callback->($status)
223	aio_mknod $path, $mode, $dev, $callback->($status)	229	aio_mknod $pathname, $mode, $dev, $callback->($status)
224	aio_link $srcpath, $dstpath, $callback->($status)	230	aio_link $srcpath, $dstpath, $callback->($status)
225	aio_symlink $srcpath, $dstpath, $callback->($status)	231	aio_symlink $srcpath, $dstpath, $callback->($status)
226	aio_readlink $path, $callback->($link)	232	aio_readlink $pathname, $callback->($link)
		233	aio_realpath $pathname, $callback->($link)
227	aio_rename $srcpath, $dstpath, $callback->($status)	234	aio_rename $srcpath, $dstpath, $callback->($status)
228	aio_mkdir $pathname, $mode, $callback->($status)	235	aio_mkdir $pathname, $mode, $callback->($status)
229	aio_rmdir $pathname, $callback->($status)	236	aio_rmdir $pathname, $callback->($status)
230	aio_readdir $pathname, $callback->($entries)	237	aio_readdir $pathname, $callback->($entries)
231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	238	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	239	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	240	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
234	aio_load $path, $data, $callback->($status)	242	aio_load $pathname, $data, $callback->($status)
235	aio_copy $srcpath, $dstpath, $callback->($status)	243	aio_copy $srcpath, $dstpath, $callback->($status)
236	aio_move $srcpath, $dstpath, $callback->($status)	244	aio_move $srcpath, $dstpath, $callback->($status)
237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238	aio_rmtree $path, $callback->($status)	245	aio_rmtree $pathname, $callback->($status)
239	aio_sync $callback->($status)	246	aio_sync $callback->($status)
		247	aio_syncfs $fh, $callback->($status)
240	aio_fsync $fh, $callback->($status)	248	aio_fsync $fh, $callback->($status)
241	aio_fdatasync $fh, $callback->($status)	249	aio_fdatasync $fh, $callback->($status)
242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	250	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243	aio_pathsync $path, $callback->($status)	251	aio_pathsync $pathname, $callback->($status)
244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	252	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	253	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	254	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247	aio_mlockall $flags, $callback->($status)	255	aio_mlockall $flags, $callback->($status)
248	aio_group $callback->(...)	256	aio_group $callback->(...)
…		…
266	IO::AIO::nready	274	IO::AIO::nready
267	IO::AIO::npending	275	IO::AIO::npending
268		276
269	IO::AIO::sendfile $ofh, $ifh, $offset, $count	277	IO::AIO::sendfile $ofh, $ifh, $offset, $count
270	IO::AIO::fadvise $fh, $offset, $len, $advice	278	IO::AIO::fadvise $fh, $offset, $len, $advice
		279	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		280	IO::AIO::munmap $scalar
271	IO::AIO::madvise $scalar, $offset, $length, $advice	281	IO::AIO::madvise $scalar, $offset, $length, $advice
272	IO::AIO::mprotect $scalar, $offset, $length, $protect	282	IO::AIO::mprotect $scalar, $offset, $length, $protect
273	IO::AIO::munlock $scalar, $offset = 0, $length = undef	283	IO::AIO::munlock $scalar, $offset = 0, $length = undef
274	IO::AIO::munlockall	284	IO::AIO::munlockall
275		285
276	=head2 AIO REQUEST FUNCTIONS	286	=head2 API NOTES
277		287
278	All the C<aio_*> calls are more or less thin wrappers around the syscall	288	All the C<aio_*> calls are more or less thin wrappers around the syscall
279	with the same name (sans C<aio_>). The arguments are similar or identical,	289	with the same name (sans C<aio_>). The arguments are similar or identical,
280	and they all accept an additional (and optional) C<$callback> argument	290	and they all accept an additional (and optional) C<$callback> argument
281	which must be a code reference. This code reference will get called with	291	which must be a code reference. This code reference will be called after
282	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	292	the syscall has been executed in an asynchronous fashion. The results
283	perl, which usually delivers "false") as its sole argument after the given	293	of the request will be passed as arguments to the callback (and, if an
284	syscall has been executed asynchronously.	294	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		295	most syscalls return C<-1> on error, unlike perl, which usually delivers
		296	"false").
		297
		298	Some requests (such as C<aio_readdir>) pass the actual results and
		299	communicate failures by passing C<undef>.
285		300
286	All functions expecting a filehandle keep a copy of the filehandle	301	All functions expecting a filehandle keep a copy of the filehandle
287	internally until the request has finished.	302	internally until the request has finished.
288		303
289	All functions return request objects of type L<IO::AIO::REQ> that allow	304	All functions return request objects of type L<IO::AIO::REQ> that allow
290	further manipulation of those requests while they are in-flight.	305	further manipulation of those requests while they are in-flight.
291		306
292	The pathnames you pass to these routines I<must> be absolute and	307	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	308	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	309	current working directory could have changed. Alternatively, you can
295	changed. Alternatively, you can make sure that you never change the	310	make sure that you never change the current working directory anywhere
296	current working directory anywhere in the program and then use relative	311	in the program and then use relative paths. You can also take advantage
297	paths.	312	of IO::AIOs working directory abstraction, that lets you specify paths
		313	relative to some previously-opened "working directory object" - see the
		314	description of the C<IO::AIO::WD> class later in this document.
298		315
299	To encode pathnames as octets, either make sure you either: a) always pass	316	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	317	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	318	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	319	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)	320	effect in the user environment, d) use Glib::filename_from_unicode on
304	use something else to ensure your scalar has the correct contents.	321	unicode filenames or e) use something else to ensure your scalar has the
		322	correct contents.
305		323
306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	324	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
307	handles correctly whether it is set or not.	325	handles correctly whether it is set or not.
		326
		327	=head2 AIO REQUEST FUNCTIONS
308		328
309	=over 4	329	=over 4
310		330
311	=item $prev_pri = aioreq_pri [$pri]	331	=item $prev_pri = aioreq_pri [$pri]
312		332
…		…
342		362
343		363
344	=item aio_open $pathname, $flags, $mode, $callback->($fh)	364	=item aio_open $pathname, $flags, $mode, $callback->($fh)
345		365
346	Asynchronously open or create a file and call the callback with a newly	366	Asynchronously open or create a file and call the callback with a newly
347	created filehandle for the file.	367	created filehandle for the file (or C<undef> in case of an error).
348		368
349	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	369	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
350	for an explanation.	370	for an explanation.
351		371
352	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	372	The C<$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	415	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.	416	free for reuse until the perl filehandle is closed.
397		417
398	=cut	418	=cut
399		419
		420	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		421
		422	Seeks the filehandle to the new C<$offset>, similarly to perl's
		423	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		424	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		425	C<IO::AIO::SEEK_END>).
		426
		427	The resulting absolute offset will be passed to the callback, or C<-1> in
		428	case of an error.
		429
		430	In theory, the C<$whence> constants could be different than the
		431	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		432	so don't panic.
		433
		434	As a GNU/Linux (and maybe Solaris) extension, also the constants
		435	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		436	could be found. No guarantees about suitability for use in C<aio_seek> or
		437	Perl's C<sysseek> can be made though, although I would naively assume they
		438	"just work".
		439
400	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	440	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
401		441
402	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	442	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
403		443
404	Reads or writes C<$length> bytes from or to the specified C<$fh> and	444	Reads or writes C<$length> bytes from or to the specified C<$fh> and
…		…
436		476
437	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	477	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
438	reading at byte offset C<$in_offset>, and starts writing at the current	478	reading at byte offset C<$in_offset>, and starts writing at the current
439	file offset of C<$out_fh>. Because of that, it is not safe to issue more	479	file offset of C<$out_fh>. Because of that, it is not safe to issue more
440	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	480	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
441	other.	481	other. The same C<$in_fh> works fine though, as this function does not
		482	move or use the file offset of C<$in_fh>.
442		483
443	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than	484	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
444	are written, and there is no way to find out how many bytes have been read	485	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	486	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>	487	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.	488	C<$length> one can assume that C<$length> bytes have been read.
448		489
449	Unlike with other C<aio_> functions, it makes a lot of sense to use	490	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	491	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
451	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while	492	the C<$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	493	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	494	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	495	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	496	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	497	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
457	much better.	498	resource usage.
458		499
459	This call tries to make use of a native C<sendfile> syscall to provide	500	This call tries to make use of a native C<sendfile>-like syscall to
460	zero-copy operation. For this to work, C<$out_fh> should refer to a	501	provide zero-copy operation. For this to work, C<$out_fh> should refer to
461	socket, and C<$in_fh> should refer to an mmap'able file.	502	a socket, and C<$in_fh> should refer to an mmap'able file.
462		503
463	If a native sendfile cannot be found or it fails with C<ENOSYS>,	504	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>,	505	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	506	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.	507	type of filehandle regardless of the limitations of the operating system.
		508
		509	As native sendfile syscalls (as practically any non-POSIX interface hacked
		510	together in a hurry to improve benchmark numbers) tend to be rather buggy
		511	on many systems, this implementation tries to work around some known bugs
		512	in Linux and FreeBSD kernels (probably others, too), but that might fail,
		513	so you really really should check the return value of C<aio_sendfile> -
		514	fewre bytes than expected might have been transferred.
467		515
468		516
469	=item aio_readahead $fh,$offset,$length, $callback->($retval)	517	=item aio_readahead $fh,$offset,$length, $callback->($retval)
470		518
471	C<aio_readahead> populates the page cache with data from a file so that	519	C<aio_readahead> populates the page cache with data from a file so that
…		…
555	namemax => 255,	603	namemax => 255,
556	frsize => 1024,	604	frsize => 1024,
557	fsid => 1810	605	fsid => 1810
558	}	606	}
559		607
		608	Here is a (likely partial) list of fsid values used by Linux - it is safe
		609	to hardcode these when the $^O is C<linux>:
		610
		611	0x0000adf5 adfs
		612	0x0000adff affs
		613	0x5346414f afs
		614	0x09041934 anon-inode filesystem
		615	0x00000187 autofs
		616	0x42465331 befs
		617	0x1badface bfs
		618	0x42494e4d binfmt_misc
		619	0x9123683e btrfs
		620	0x0027e0eb cgroupfs
		621	0xff534d42 cifs
		622	0x73757245 coda
		623	0x012ff7b7 coh
		624	0x28cd3d45 cramfs
		625	0x453dcd28 cramfs-wend (wrong endianness)
		626	0x64626720 debugfs
		627	0x00001373 devfs
		628	0x00001cd1 devpts
		629	0x0000f15f ecryptfs
		630	0x00414a53 efs
		631	0x0000137d ext
		632	0x0000ef53 ext2/ext3
		633	0x0000ef51 ext2
		634	0x00004006 fat
		635	0x65735546 fuseblk
		636	0x65735543 fusectl
		637	0x0bad1dea futexfs
		638	0x01161970 gfs2
		639	0x47504653 gpfs
		640	0x00004244 hfs
		641	0xf995e849 hpfs
		642	0x958458f6 hugetlbfs
		643	0x2bad1dea inotifyfs
		644	0x00009660 isofs
		645	0x000072b6 jffs2
		646	0x3153464a jfs
		647	0x6b414653 k-afs
		648	0x0bd00bd0 lustre
		649	0x0000137f minix
		650	0x0000138f minix 30 char names
		651	0x00002468 minix v2
		652	0x00002478 minix v2 30 char names
		653	0x00004d5a minix v3
		654	0x19800202 mqueue
		655	0x00004d44 msdos
		656	0x0000564c novell
		657	0x00006969 nfs
		658	0x6e667364 nfsd
		659	0x00003434 nilfs
		660	0x5346544e ntfs
		661	0x00009fa1 openprom
		662	0x7461636F ocfs2
		663	0x00009fa0 proc
		664	0x6165676c pstorefs
		665	0x0000002f qnx4
		666	0x858458f6 ramfs
		667	0x52654973 reiserfs
		668	0x00007275 romfs
		669	0x67596969 rpc_pipefs
		670	0x73636673 securityfs
		671	0xf97cff8c selinux
		672	0x0000517b smb
		673	0x534f434b sockfs
		674	0x73717368 squashfs
		675	0x62656572 sysfs
		676	0x012ff7b6 sysv2
		677	0x012ff7b5 sysv4
		678	0x01021994 tmpfs
		679	0x15013346 udf
		680	0x00011954 ufs
		681	0x54190100 ufs byteswapped
		682	0x00009fa2 usbdevfs
		683	0x01021997 v9fs
		684	0xa501fcf5 vxfs
		685	0xabba1974 xenfs
		686	0x012ff7b4 xenix
		687	0x58465342 xfs
		688	0x012fd16d xia
560		689
561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	690	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
562		691
563	Works like perl's C<utime> function (including the special case of $atime	692	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	693	and $mtime being undef). Fractional times are supported if the underlying
…		…
592	=item aio_truncate $fh_or_path, $offset, $callback->($status)	721	=item aio_truncate $fh_or_path, $offset, $callback->($status)
593		722
594	Works like truncate(2) or ftruncate(2).	723	Works like truncate(2) or ftruncate(2).
595		724
596		725
		726	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		727
		728	Allocates or freed disk space according to the C<$mode> argument. See the
		729	linux C<fallocate> docuemntation for details.
		730
		731	C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
		732	to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \|
		733	IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
		734
		735	The file system block size used by C<fallocate> is presumably the
		736	C<f_bsize> returned by C<statvfs>.
		737
		738	If C<fallocate> isn't available or cannot be emulated (currently no
		739	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		740
		741
597	=item aio_chmod $fh_or_path, $mode, $callback->($status)	742	=item aio_chmod $fh_or_path, $mode, $callback->($status)
598		743
599	Works like perl's C<chmod> function.	744	Works like perl's C<chmod> function.
600		745
601		746
…		…
603		748
604	Asynchronously unlink (delete) a file and call the callback with the	749	Asynchronously unlink (delete) a file and call the callback with the
605	result code.	750	result code.
606		751
607		752
608	=item aio_mknod $path, $mode, $dev, $callback->($status)	753	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
609		754
610	[EXPERIMENTAL]	755	[EXPERIMENTAL]
611		756
612	Asynchronously create a device node (or fifo). See mknod(2).	757	Asynchronously create a device node (or fifo). See mknod(2).
613		758
614	The only (POSIX-) portable way of calling this function is:	759	The only (POSIX-) portable way of calling this function is:
615		760
616	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	761	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
617		762
618	See C<aio_stat> for info about some potentially helpful extra constants	763	See C<aio_stat> for info about some potentially helpful extra constants
619	and functions.	764	and functions.
620		765
621	=item aio_link $srcpath, $dstpath, $callback->($status)	766	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
628		773
629	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	774	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
630	the path C<$dstpath> and call the callback with the result code.	775	the path C<$dstpath> and call the callback with the result code.
631		776
632		777
633	=item aio_readlink $path, $callback->($link)	778	=item aio_readlink $pathname, $callback->($link)
634		779
635	Asynchronously read the symlink specified by C<$path> and pass it to	780	Asynchronously read the symlink specified by C<$path> and pass it to
636	the callback. If an error occurs, nothing or undef gets passed to the	781	the callback. If an error occurs, nothing or undef gets passed to the
637	callback.	782	callback.
638		783
639		784
		785	=item aio_realpath $pathname, $callback->($path)
		786
		787	Asynchronously make the path absolute and resolve any symlinks in
		788	C<$path>. The resulting path only consists of directories (same as
		789	L<Cwd::realpath>).
		790
		791	This request can be used to get the absolute path of the current working
		792	directory by passing it a path of F<.> (a single dot).
		793
		794
640	=item aio_rename $srcpath, $dstpath, $callback->($status)	795	=item aio_rename $srcpath, $dstpath, $callback->($status)
641		796
642	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	797	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
643	rename(2) and call the callback with the result code.	798	rename(2) and call the callback with the result code.
		799
		800	On systems that support the AIO::WD working directory abstraction
		801	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		802	of failing, C<rename> is called on the absolute path of C<$wd>.
644		803
645		804
646	=item aio_mkdir $pathname, $mode, $callback->($status)	805	=item aio_mkdir $pathname, $mode, $callback->($status)
647		806
648	Asynchronously mkdir (create) a directory and call the callback with	807	Asynchronously mkdir (create) a directory and call the callback with
…		…
653	=item aio_rmdir $pathname, $callback->($status)	812	=item aio_rmdir $pathname, $callback->($status)
654		813
655	Asynchronously rmdir (delete) a directory and call the callback with the	814	Asynchronously rmdir (delete) a directory and call the callback with the
656	result code.	815	result code.
657		816
		817	On systems that support the AIO::WD working directory abstraction
		818	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		819	C<rmdir> is called on the absolute path of C<$wd>.
		820
658		821
659	=item aio_readdir $pathname, $callback->($entries)	822	=item aio_readdir $pathname, $callback->($entries)
660		823
661	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	824	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	825	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
666	array-ref with the filenames.	829	array-ref with the filenames.
667		830
668		831
669	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	832	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
670		833
671	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	834	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	835	tune behaviour and output format. In case of an error, C<$entries> will be
673	C<undef>.	836	C<undef>.
674		837
675	The flags are a combination of the following constants, ORed together (the	838	The flags are a combination of the following constants, ORed together (the
676	flags will also be passed to the callback, possibly modified):	839	flags will also be passed to the callback, possibly modified):
677		840
…		…
724		887
725	=item IO::AIO::READDIR_FOUND_UNKNOWN	888	=item IO::AIO::READDIR_FOUND_UNKNOWN
726		889
727	This flag should not be set when calling C<aio_readdirx>. Instead, it	890	This flag should not be set when calling C<aio_readdirx>. Instead, it
728	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	891	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
729	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	892	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
730	C<$type>'s are known, which can be used to speed up some algorithms.	893	C<$type>'s are known, which can be used to speed up some algorithms.
731		894
732	=back	895	=back
733		896
734		897
735	=item aio_load $path, $data, $callback->($status)	898	=item aio_load $pathname, $data, $callback->($status)
736		899
737	This is a composite request that tries to fully load the given file into	900	This is a composite request that tries to fully load the given file into
738	memory. Status is the same as with aio_read.	901	memory. Status is the same as with aio_read.
739		902
740	=cut	903	=cut
…		…
862	if ($_[0] && $! == EXDEV) {	1025	if ($_[0] && $! == EXDEV) {
863	aioreq_pri $pri;	1026	aioreq_pri $pri;
864	add $grp aio_copy $src, $dst, sub {	1027	add $grp aio_copy $src, $dst, sub {
865	$grp->result ($_[0]);	1028	$grp->result ($_[0]);
866		1029
867	if (!$_[0]) {	1030	unless ($_[0]) {
868	aioreq_pri $pri;	1031	aioreq_pri $pri;
869	add $grp aio_unlink $src;	1032	add $grp aio_unlink $src;
870	}	1033	}
871	};	1034	};
872	} else {	1035	} else {
…		…
875	};	1038	};
876		1039
877	$grp	1040	$grp
878	}	1041	}
879		1042
880	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1043	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
881		1044
882	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1045	Scans a directory (similar to C<aio_readdir>) but additionally tries to
883	efficiently separate the entries of directory C<$path> into two sets of	1046	efficiently separate the entries of directory C<$path> into two sets of
884	names, directories you can recurse into (directories), and ones you cannot	1047	names, directories you can recurse into (directories), and ones you cannot
885	recurse into (everything else, including symlinks to directories).	1048	recurse into (everything else, including symlinks to directories).
…		…
916	Then entries will be sorted into likely directories a non-initial dot	1079	Then entries will be sorted into likely directories a non-initial dot
917	currently) and likely non-directories (see C<aio_readdirx>). Then every	1080	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,	1081	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	1082	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	1083	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	1084	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	1085	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	1086	data (e.g. ext2fs filetype feature), even on systems that cannot return
924	the filetype information on readdir.	1087	the filetype information on readdir.
925		1088
926	If the known number of directories (link count - 2) has been reached, the	1089	If the known number of directories (link count - 2) has been reached, the
…		…
942		1105
943	my $grp = aio_group $cb;	1106	my $grp = aio_group $cb;
944		1107
945	$maxreq = 4 if $maxreq <= 0;	1108	$maxreq = 4 if $maxreq <= 0;
946		1109
947	# stat once	1110	# get a wd object
948	aioreq_pri $pri;	1111	aioreq_pri $pri;
949	add $grp aio_stat $path, sub {	1112	add $grp aio_wd $path, sub {
		1113	$_[0]
950	return $grp->result () if $_[0];	1114	or return $grp->result ();
951	my $now = time;
952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
953		1115
954	# read the directory entries	1116	my $wd = [shift, "."];
		1117
		1118	# stat once
955	aioreq_pri $pri;	1119	aioreq_pri $pri;
956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1120	add $grp aio_stat $wd, sub {
957	my $entries = shift
958	or return $grp->result ();	1121	return $grp->result () if $_[0];
		1122	my $now = time;
		1123	my $hash1 = join ":", (stat _)[0,1,3,7,9];
959		1124
960	# stat the dir another time	1125	# read the directory entries
961	aioreq_pri $pri;	1126	aioreq_pri $pri;
		1127	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1128	my $entries = shift
		1129	or return $grp->result ();
		1130
		1131	# stat the dir another time
		1132	aioreq_pri $pri;
962	add $grp aio_stat $path, sub {	1133	add $grp aio_stat $wd, sub {
963	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1134	my $hash2 = join ":", (stat _)[0,1,3,7,9];
964		1135
965	my $ndirs;	1136	my $ndirs;
966		1137
967	# take the slow route if anything looks fishy	1138	# take the slow route if anything looks fishy
968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1139	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
969	$ndirs = -1;	1140	$ndirs = -1;
970	} else {	1141	} else {
971	# if nlink == 2, we are finished	1142	# if nlink == 2, we are finished
972	# for non-posix-fs's, we rely on nlink < 2	1143	# for non-posix-fs's, we rely on nlink < 2
973	$ndirs = (stat _)[3] - 2	1144	$ndirs = (stat _)[3] - 2
974	or return $grp->result ([], $entries);	1145	or return $grp->result ([], $entries);
975	}	1146	}
976		1147
977	my (@dirs, @nondirs);	1148	my (@dirs, @nondirs);
978		1149
979	my $statgrp = add $grp aio_group sub {	1150	my $statgrp = add $grp aio_group sub {
980	$grp->result (\@dirs, \@nondirs);	1151	$grp->result (\@dirs, \@nondirs);
981	};	1152	};
982		1153
983	limit $statgrp $maxreq;	1154	limit $statgrp $maxreq;
984	feed $statgrp sub {	1155	feed $statgrp sub {
985	return unless @$entries;	1156	return unless @$entries;
986	my $entry = shift @$entries;	1157	my $entry = shift @$entries;
987		1158
988	aioreq_pri $pri;	1159	aioreq_pri $pri;
		1160	$wd->[1] = "$entry/.";
989	add $statgrp aio_stat "$path/$entry/.", sub {	1161	add $statgrp aio_stat $wd, sub {
990	if ($_[0] < 0) {	1162	if ($_[0] < 0) {
991	push @nondirs, $entry;	1163	push @nondirs, $entry;
992	} else {	1164	} else {
993	# need to check for real directory	1165	# need to check for real directory
994	aioreq_pri $pri;	1166	aioreq_pri $pri;
		1167	$wd->[1] = $entry;
995	add $statgrp aio_lstat "$path/$entry", sub {	1168	add $statgrp aio_lstat $wd, sub {
996	if (-d _) {	1169	if (-d _) {
997	push @dirs, $entry;	1170	push @dirs, $entry;
998		1171
999	unless (--$ndirs) {	1172	unless (--$ndirs) {
1000	push @nondirs, @$entries;	1173	push @nondirs, @$entries;
1001	feed $statgrp;	1174	feed $statgrp;
		1175	}
		1176	} else {
		1177	push @nondirs, $entry;
1002	}	1178	}
1003	} else {
1004	push @nondirs, $entry;
1005	}	1179	}
1006	}	1180	}
1007	}	1181	};
1008	};	1182	};
1009	};	1183	};
1010	};	1184	};
1011	};	1185	};
1012	};	1186	};
1013		1187
1014	$grp	1188	$grp
1015	}	1189	}
1016		1190
1017	=item aio_rmtree $path, $callback->($status)	1191	=item aio_rmtree $pathname, $callback->($status)
1018		1192
1019	Delete a directory tree starting (and including) C<$path>, return the	1193	Delete a directory tree starting (and including) C<$path>, return the
1020	status of the final C<rmdir> only. This is a composite request that	1194	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	1195	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1022	everything else.	1196	everything else.
1023		1197
1024	=cut	1198	=cut
1025		1199
…		…
1064	callback with the fdatasync result code.	1238	callback with the fdatasync result code.
1065		1239
1066	If this call isn't available because your OS lacks it or it couldn't be	1240	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.	1241	detected, it will be emulated by calling C<fsync> instead.
1068		1242
		1243	=item aio_syncfs $fh, $callback->($status)
		1244
		1245	Asynchronously call the syncfs syscall to sync the filesystem associated
		1246	to the given filehandle and call the callback with the syncfs result
		1247	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1248	errno to C<ENOSYS> nevertheless.
		1249
1069	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1250	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1070		1251
1071	Sync the data portion of the file specified by C<$offset> and C<$length>	1252	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	1253	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	1254	sync_file_range call. If sync_file_range is not available or it returns
…		…
1076	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1257	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1077	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1258	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1078	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1259	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1079	manpage for details.	1260	manpage for details.
1080		1261
1081	=item aio_pathsync $path, $callback->($status)	1262	=item aio_pathsync $pathname, $callback->($status)
1082		1263
1083	This request tries to open, fsync and close the given path. This is a	1264	This request tries to open, fsync and close the given path. This is a
1084	composite request intended to sync directories after directory operations	1265	composite request intended to sync directories after directory operations
1085	(E.g. rename). This might not work on all operating systems or have any	1266	(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	1267	specific effect, but usually it makes sure that directory changes get
…		…
1138		1319
1139	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1320	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1140	scalars.	1321	scalars.
1141		1322
1142	It touches (reads or writes) all memory pages in the specified	1323	It touches (reads or writes) all memory pages in the specified
1143	range inside the scalar. All caveats and parameters are the same	1324	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	1325	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	1326	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	1327	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1147	writing an octet from it, which dirties the page).	1328	writing an octet from it, which dirties the page).
1148		1329
1149	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1330	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1150		1331
1151	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1332	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1182	documented under L<MISCELLANEOUS FUNCTIONS>.	1363	documented under L<MISCELLANEOUS FUNCTIONS>.
1183		1364
1184	Example: asynchronously lock all current and future pages into memory.	1365	Example: asynchronously lock all current and future pages into memory.
1185		1366
1186	aio_mlockall IO::AIO::MCL_FUTURE;	1367	aio_mlockall IO::AIO::MCL_FUTURE;
		1368
		1369	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1370
		1371	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1372	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1373	the ioctl is not available on your OS, then this request will fail with
		1374	C<ENOSYS>.
		1375
		1376	C<$start> is the starting offset to query extents for, C<$length> is the
		1377	size of the range to query - if it is C<undef>, then the whole file will
		1378	be queried.
		1379
		1380	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1381	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1382	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1383	the data portion.
		1384
		1385	C<$count> is the maximum number of extent records to return. If it is
		1386	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1387	case, if it is C<0>, then the callback receives the number of extents
		1388	instead of the extents themselves (which is unreliable, see below).
		1389
		1390	If an error occurs, the callback receives no arguments. The special
		1391	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1392
		1393	Otherwise, the callback receives an array reference with extent
		1394	structures. Each extent structure is an array reference itself, with the
		1395	following members:
		1396
		1397	[$logical, $physical, $length, $flags]
		1398
		1399	Flags is any combination of the following flag values (typically either C<0>
		1400	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1401
		1402	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1403	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1404	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1405	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1406	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1407	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1408
		1409	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1410	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1411	it to return all extents of a range for files with large number of
		1412	extents. The code works around all these issues if C<$count> is undef.
1187		1413
1188	=item aio_group $callback->(...)	1414	=item aio_group $callback->(...)
1189		1415
1190	This is a very special aio request: Instead of doing something, it is a	1416	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	1417	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	1454	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	1455	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.	1456	except to put your application under artificial I/O pressure.
1231		1457
1232	=back	1458	=back
		1459
		1460
		1461	=head2 IO::AIO::WD - multiple working directories
		1462
		1463	Your process only has one current working directory, which is used by all
		1464	threads. This makes it hard to use relative paths (some other component
		1465	could call C<chdir> at any time, and it is hard to control when the path
		1466	will be used by IO::AIO).
		1467
		1468	One solution for this is to always use absolute paths. This usually works,
		1469	but can be quite slow (the kernel has to walk the whole path on every
		1470	access), and can also be a hassle to implement.
		1471
		1472	Newer POSIX systems have a number of functions (openat, fdopendir,
		1473	futimensat and so on) that make it possible to specify working directories
		1474	per operation.
		1475
		1476	For portability, and because the clowns who "designed", or shall I write,
		1477	perpetrated this new interface were obviously half-drunk, this abstraction
		1478	cannot be perfect, though.
		1479
		1480	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1481	object. This object stores the canonicalised, absolute version of the
		1482	path, and on systems that allow it, also a directory file descriptor.
		1483
		1484	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1485	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1486	object and a pathname instead (or the IO::AIO::WD object alone, which
		1487	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1488	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1489	to that IO::AIO::WD object.
		1490
		1491	For example, to get a wd object for F</etc> and then stat F<passwd>
		1492	inside, you would write:
		1493
		1494	aio_wd "/etc", sub {
		1495	my $etcdir = shift;
		1496
		1497	# although $etcdir can be undef on error, there is generally no reason
		1498	# to check for errors here, as aio_stat will fail with ENOENT
		1499	# when $etcdir is undef.
		1500
		1501	aio_stat [$etcdir, "passwd"], sub {
		1502	# yay
		1503	};
		1504	};
		1505
		1506	That C<aio_wd> is a request and not a normal function shows that creating
		1507	an IO::AIO::WD object is itself a potentially blocking operation, which is
		1508	why it is done asynchronously.
		1509
		1510	To stat the directory obtained with C<aio_wd> above, one could write
		1511	either of the following three request calls:
		1512
		1513	aio_lstat "/etc" , sub { ... # pathname as normal string
		1514	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1515	aio_lstat $wd , sub { ... # shorthand for the previous
		1516
		1517	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1518	object and the pathname string, so you could write the following without
		1519	causing any issues due to C<$path> getting reused:
		1520
		1521	my $path = [$wd, undef];
		1522
		1523	for my $name (qw(abc def ghi)) {
		1524	$path->[1] = $name;
		1525	aio_stat $path, sub {
		1526	# ...
		1527	};
		1528	}
		1529
		1530	There are some caveats: when directories get renamed (or deleted), the
		1531	pathname string doesn't change, so will point to the new directory (or
		1532	nowhere at all), while the directory fd, if available on the system,
		1533	will still point to the original directory. Most functions accepting a
		1534	pathname will use the directory fd on newer systems, and the string on
		1535	older systems. Some functions (such as realpath) will always rely on the
		1536	string form of the pathname.
		1537
		1538	So this functionality is mainly useful to get some protection against
		1539	C<chdir>, to easily get an absolute path out of a relative path for future
		1540	reference, and to speed up doing many operations in the same directory
		1541	(e.g. when stat'ing all files in a directory).
		1542
		1543	The following functions implement this working directory abstraction:
		1544
		1545	=over 4
		1546
		1547	=item aio_wd $pathname, $callback->($wd)
		1548
		1549	Asynchonously canonicalise the given pathname and convert it to an
		1550	IO::AIO::WD object representing it. If possible and supported on the
		1551	system, also open a directory fd to speed up pathname resolution relative
		1552	to this working directory.
		1553
		1554	If something goes wrong, then C<undef> is passwd to the callback instead
		1555	of a working directory object and C<$!> is set appropriately. Since
		1556	passing C<undef> as working directory component of a pathname fails the
		1557	request with C<ENOENT>, there is often no need for error checking in the
		1558	C<aio_wd> callback, as future requests using the value will fail in the
		1559	expected way.
		1560
		1561	If this call isn't available because your OS lacks it or it couldn't be
		1562	detected, it will be emulated by calling C<fsync> instead.
		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
…		…
1564	Sets the minimum idle timeout (default 10) after which worker threads are	1922	Sets the minimum idle timeout (default 10) after which worker threads are
1565	allowed to exit. SEe C<IO::AIO::max_idle>.	1923	allowed to exit. SEe C<IO::AIO::max_idle>.
1566		1924
1567	=item IO::AIO::max_outstanding $maxreqs	1925	=item IO::AIO::max_outstanding $maxreqs
1568		1926
		1927	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1928	you do queue up more than this number of requests, the next call to
		1929	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1930	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1931	longer exceeded.
		1932
		1933	In other words, this setting does not enforce a queue limit, but can be
		1934	used to make poll functions block if the limit is exceeded.
		1935
1569	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
1570	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
1571	use an C<aio_group> together with a feed callback.	1938	use an C<aio_group> together with a feed callback.
1572		1939
1573	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1940	It's main use is in scripts without an event loop - when you want to stat
1574	do queue up more than this number of requests, the next call to the	1941	a lot of files, you can write somehting like this:
1575	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1576	function will block until the limit is no longer exceeded.
1577		1942
1578	The default value is very large, so there is no practical limit on the	1943	IO::AIO::max_outstanding 32;
1579	number of outstanding requests.
1580		1944
1581	You can still queue as many requests as you want. Therefore,	1945	for my $path (...) {
1582	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1946	aio_stat $path , ...;
1583	as a stop gap to shield against fatal memory overflow (with large values).	1947	IO::AIO::poll_cb;
		1948	}
		1949
		1950	IO::AIO::flush;
		1951
		1952	The call to C<poll_cb> inside the loop will normally return instantly, but
		1953	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1954	some requests have been handled. This keeps the loop from pushing a large
		1955	number of C<aio_stat> requests onto the queue.
		1956
		1957	The default value for C<max_outstanding> is very large, so there is no
		1958	practical limit on the number of outstanding requests.
1584		1959
1585	=back	1960	=back
1586		1961
1587	=head3 STATISTICAL INFORMATION	1962	=head3 STATISTICAL INFORMATION
1588		1963
…		…
1628		2003
1629	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2004	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1630		2005
1631	Simply calls the C<posix_fadvise> function (see its	2006	Simply calls the C<posix_fadvise> function (see its
1632	manpage for details). The following advice constants are	2007	manpage for details). The following advice constants are
1633	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2008	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1634	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2009	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1635	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2010	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1636		2011
1637	On systems that do not implement C<posix_fadvise>, this function returns	2012	On systems that do not implement C<posix_fadvise>, this function returns
1638	ENOSYS, otherwise the return value of C<posix_fadvise>.	2013	ENOSYS, otherwise the return value of C<posix_fadvise>.
1639		2014
1640	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2015	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1641		2016
1642	Simply calls the C<posix_madvise> function (see its	2017	Simply calls the C<posix_madvise> function (see its
1643	manpage for details). The following advice constants are	2018	manpage for details). The following advice constants are
1644	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2019	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1645	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2020	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1646		2021
1647	On systems that do not implement C<posix_madvise>, this function returns	2022	On systems that do not implement C<posix_madvise>, this function returns
1648	ENOSYS, otherwise the return value of C<posix_madvise>.	2023	ENOSYS, otherwise the return value of C<posix_madvise>.
1649		2024
1650	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2025	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1651		2026
1652	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2027	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1653	$scalar (see its manpage for details). The following protect	2028	$scalar (see its manpage for details). The following protect
1654	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2029	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1655	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2030	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1656		2031
1657	On systems that do not implement C<mprotect>, this function returns	2032	On systems that do not implement C<mprotect>, this function returns
1658	ENOSYS, otherwise the return value of C<mprotect>.	2033	ENOSYS, otherwise the return value of C<mprotect>.
1659		2034
1660	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2035	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1661		2036
1662	Memory-maps a file (or anonymous memory range) and attaches it to the	2037	Memory-maps a file (or anonymous memory range) and attaches it to the
1663	given C<$scalar>, which will act like a string scalar.	2038	given C<$scalar>, which will act like a string scalar. Returns true on
		2039	success, and false otherwise.
1664		2040
1665	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2041	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1666	change the string length, and most read-only operations such as copying it	2042	change the string length, and most read-only operations such as copying it
1667	or searching it with regexes and so on.	2043	or searching it with regexes and so on.
1668		2044
…		…
1721	Calls the C<munlockall> function.	2097	Calls the C<munlockall> function.
1722		2098
1723	On systems that do not implement C<munlockall>, this function returns	2099	On systems that do not implement C<munlockall>, this function returns
1724	ENOSYS, otherwise the return value of C<munlockall>.	2100	ENOSYS, otherwise the return value of C<munlockall>.
1725		2101
		2102	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2103
		2104	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2105	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2106	should be the file offset.
		2107
		2108	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2109	silently corrupt the data in this case.
		2110
		2111	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2112	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2113	C<IO::AIO::SPLICE_F_GIFT>.
		2114
		2115	See the C<splice(2)> manpage for details.
		2116
		2117	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2118
		2119	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
		2120	description for C<IO::AIO::splice> above for details.
		2121
1726	=back	2122	=back
1727		2123
1728	=cut	2124	=cut
1729		2125
1730	min_parallel 8;	2126	min_parallel 8;
…		…
1764	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2160	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1765	\&IO::AIO::poll_cb);	2161	\&IO::AIO::poll_cb);
1766		2162
1767	=head2 FORK BEHAVIOUR	2163	=head2 FORK BEHAVIOUR
1768		2164
1769	This module should do "the right thing" when the process using it forks:	2165	Usage of pthreads in a program changes the semantics of fork
		2166	considerably. Specifically, only async-safe functions can be called after
		2167	fork. Perl doesn't know about this, so in general, you cannot call fork
		2168	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2169	pthreads, so this applies, but many other extensions and (for inexplicable
		2170	reasons) perl itself often is linked against pthreads, so this limitation
		2171	applies to quite a lot of perls.
1770		2172
1771	Before the fork, IO::AIO enters a quiescent state where no requests	2173	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1772	can be added in other threads and no results will be processed. After	2174	only works in the process that loaded it. Forking is fully supported, but
1773	the fork the parent simply leaves the quiescent state and continues	2175	using IO::AIO in the child is not.
1774	request/result processing, while the child frees the request/result queue
1775	(so that the requests started before the fork will only be handled in the
1776	parent). Threads will be started on demand until the limit set in the
1777	parent process has been reached again.
1778		2176
1779	In short: the parent will, after a short pause, continue as if fork had	2177	You might get around by not I<using> IO::AIO before (or after)
1780	not been called, while the child will act as if IO::AIO has not been used	2178	forking. You could also try to call the L<IO::AIO::reinit> function in the
1781	yet.	2179	child:
		2180
		2181	=over 4
		2182
		2183	=item IO::AIO::reinit
		2184
		2185	Abandons all current requests and I/O threads and simply reinitialises all
		2186	data structures. This is not an operation supported by any standards, but
		2187	happens to work on GNU/Linux and some newer BSD systems.
		2188
		2189	The only reasonable use for this function is to call it after forking, if
		2190	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2191	the process will result in undefined behaviour. Calling it at any time
		2192	will also result in any undefined (by POSIX) behaviour.
		2193
		2194	=back
1782		2195
1783	=head2 MEMORY USAGE	2196	=head2 MEMORY USAGE
1784		2197
1785	Per-request usage:	2198	Per-request usage:
1786		2199

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.194 by root, Fri May 27 00:44:49 2011 UTC vs. Revision 1.241 by root, Fri Dec 28 07:33:41 2012 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.194 by root, Fri May 27 00:44:49 2011 UTC vs.
Revision 1.241 by root, Fri Dec 28 07:33:41 2012 UTC