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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs.
Revision 1.252 by root, Sat Jun 13 00:06:13 2015 UTC

…		…
68	=head2 EXAMPLE	68	=head2 EXAMPLE
69		69
70	This is a simple example that uses the EV module and loads	70	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
72		72
73	use Fcntl;
74	use EV;	73	use EV;
75	use IO::AIO;	74	use IO::AIO;
76		75
77	# register the IO::AIO callback with EV	76	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	77	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
168	use common::sense;	167	use common::sense;
169		168
170	use base 'Exporter';	169	use base 'Exporter';
171		170
172	BEGIN {	171	BEGIN {
173	our $VERSION = '3.93';	172	our $VERSION = 4.32;
174		173
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	174	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	175	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync aio_fsync	176	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178	aio_fdatasync aio_sync_file_range aio_fallocate	177	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
179	aio_pathsync aio_readahead	178	aio_pathsync aio_readahead aio_fiemap
180	aio_rename aio_link aio_move aio_copy aio_group	179	aio_rename aio_link aio_move aio_copy aio_group
181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182	aio_chmod aio_utime aio_truncate	181	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	182	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs);	183	aio_statvfs
		184	aio_wd);
185		185
186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
188	min_parallel max_parallel max_idle idle_timeout	188	min_parallel max_parallel max_idle idle_timeout
189	nreqs nready npending nthreads	189	nreqs nready npending nthreads
…		…
201		201
202	=head1 FUNCTIONS	202	=head1 FUNCTIONS
203		203
204	=head2 QUICK OVERVIEW	204	=head2 QUICK OVERVIEW
205		205
206	This section simply lists the prototypes of the most important functions	206	This section simply lists the prototypes most of the functions for
207	for quick reference. See the following sections for function-by-function	207	quick reference. See the following sections for function-by-function
208	documentation.	208	documentation.
209		209
		210	aio_wd $pathname, $callback->($wd)
210	aio_open $pathname, $flags, $mode, $callback->($fh)	211	aio_open $pathname, $flags, $mode, $callback->($fh)
211	aio_close $fh, $callback->($status)	212	aio_close $fh, $callback->($status)
		213	aio_seek $fh,$offset,$whence, $callback->($offs)
212	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
214	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
215	aio_readahead $fh,$offset,$length, $callback->($retval)	217	aio_readahead $fh,$offset,$length, $callback->($retval)
216	aio_stat $fh_or_path, $callback->($status)	218	aio_stat $fh_or_path, $callback->($status)
217	aio_lstat $fh, $callback->($status)	219	aio_lstat $fh, $callback->($status)
218	aio_statvfs $fh_or_path, $callback->($statvfs)	220	aio_statvfs $fh_or_path, $callback->($statvfs)
219	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
220	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)
221	aio_truncate $fh_or_path, $offset, $callback->($status)	224	aio_truncate $fh_or_path, $offset, $callback->($status)
222	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)
223	aio_unlink $pathname, $callback->($status)	227	aio_unlink $pathname, $callback->($status)
224	aio_mknod $path, $mode, $dev, $callback->($status)	228	aio_mknod $pathname, $mode, $dev, $callback->($status)
225	aio_link $srcpath, $dstpath, $callback->($status)	229	aio_link $srcpath, $dstpath, $callback->($status)
226	aio_symlink $srcpath, $dstpath, $callback->($status)	230	aio_symlink $srcpath, $dstpath, $callback->($status)
227	aio_readlink $path, $callback->($link)	231	aio_readlink $pathname, $callback->($link)
228	aio_realpath $path, $callback->($link)	232	aio_realpath $pathname, $callback->($path)
229	aio_rename $srcpath, $dstpath, $callback->($status)	233	aio_rename $srcpath, $dstpath, $callback->($status)
230	aio_mkdir $pathname, $mode, $callback->($status)	234	aio_mkdir $pathname, $mode, $callback->($status)
231	aio_rmdir $pathname, $callback->($status)	235	aio_rmdir $pathname, $callback->($status)
232	aio_readdir $pathname, $callback->($entries)	236	aio_readdir $pathname, $callback->($entries)
233	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
234	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
235	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)
236	aio_load $path, $data, $callback->($status)	241	aio_load $pathname, $data, $callback->($status)
237	aio_copy $srcpath, $dstpath, $callback->($status)	242	aio_copy $srcpath, $dstpath, $callback->($status)
238	aio_move $srcpath, $dstpath, $callback->($status)	243	aio_move $srcpath, $dstpath, $callback->($status)
239	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
240	aio_rmtree $path, $callback->($status)	244	aio_rmtree $pathname, $callback->($status)
241	aio_sync $callback->($status)	245	aio_sync $callback->($status)
		246	aio_syncfs $fh, $callback->($status)
242	aio_fsync $fh, $callback->($status)	247	aio_fsync $fh, $callback->($status)
243	aio_fdatasync $fh, $callback->($status)	248	aio_fdatasync $fh, $callback->($status)
244	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	249	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
245	aio_pathsync $path, $callback->($status)	250	aio_pathsync $pathname, $callback->($status)
246	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	251	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
247	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	252	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
248	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	253	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
249	aio_mlockall $flags, $callback->($status)	254	aio_mlockall $flags, $callback->($status)
250	aio_group $callback->(...)	255	aio_group $callback->(...)
…		…
268	IO::AIO::nready	273	IO::AIO::nready
269	IO::AIO::npending	274	IO::AIO::npending
270		275
271	IO::AIO::sendfile $ofh, $ifh, $offset, $count	276	IO::AIO::sendfile $ofh, $ifh, $offset, $count
272	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
273	IO::AIO::madvise $scalar, $offset, $length, $advice	280	IO::AIO::madvise $scalar, $offset, $length, $advice
274	IO::AIO::mprotect $scalar, $offset, $length, $protect	281	IO::AIO::mprotect $scalar, $offset, $length, $protect
275	IO::AIO::munlock $scalar, $offset = 0, $length = undef	282	IO::AIO::munlock $scalar, $offset = 0, $length = undef
276	IO::AIO::munlockall	283	IO::AIO::munlockall
277		284
278	=head2 AIO REQUEST FUNCTIONS	285	=head2 API NOTES
279		286
280	All the C<aio_*> calls are more or less thin wrappers around the syscall	287	All the C<aio_*> calls are more or less thin wrappers around the syscall
281	with the same name (sans C<aio_>). The arguments are similar or identical,	288	with the same name (sans C<aio_>). The arguments are similar or identical,
282	and they all accept an additional (and optional) C<$callback> argument	289	and they all accept an additional (and optional) C<$callback> argument
283	which must be a code reference. This code reference will get called with	290	which must be a code reference. This code reference will be called after
284	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	291	the syscall has been executed in an asynchronous fashion. The results
285	perl, which usually delivers "false") as its sole argument after the given	292	of the request will be passed as arguments to the callback (and, if an
286	syscall has been executed asynchronously.	293	error occured, in C<$!>) - 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>.
287		299
288	All functions expecting a filehandle keep a copy of the filehandle	300	All functions expecting a filehandle keep a copy of the filehandle
289	internally until the request has finished.	301	internally until the request has finished.
290		302
291	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
292	further manipulation of those requests while they are in-flight.	304	further manipulation of those requests while they are in-flight.
293		305
294	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
295	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
296	request is being executed, the current working directory could have	308	current working directory could have changed. Alternatively, you can
297	changed. Alternatively, you can make sure that you never change the	309	make sure that you never change the current working directory anywhere
298	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
299	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.
300		314
301	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
302	in filenames you got from outside (command line, readdir etc.) without	316	in filenames you got from outside (command line, readdir etc.) without
303	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
304	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
305	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
306	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.
307		322
308	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
309	handles correctly whether it is set or not.	324	handles correctly whether it is set or not.
		325
		326	=head2 AIO REQUEST FUNCTIONS
310		327
311	=over 4	328	=over 4
312		329
313	=item $prev_pri = aioreq_pri [$pri]	330	=item $prev_pri = aioreq_pri [$pri]
314		331
…		…
344		361
345		362
346	=item aio_open $pathname, $flags, $mode, $callback->($fh)	363	=item aio_open $pathname, $flags, $mode, $callback->($fh)
347		364
348	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
349	created filehandle for the file.	366	created filehandle for the file (or C<undef> in case of an error).
350		367
351	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,
352	for an explanation.	369	for an explanation.
353		370
354	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
…		…
396		413
397	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
398	free for reuse until the perl filehandle is closed.	415	free for reuse until the perl filehandle is closed.
399		416
400	=cut	417	=cut
		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".
401		438
402	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	439	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
403		440
404	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	441	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
405		442
…		…
565	namemax => 255,	602	namemax => 255,
566	frsize => 1024,	603	frsize => 1024,
567	fsid => 1810	604	fsid => 1810
568	}	605	}
569		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
570		688
571	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	689	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
572		690
573	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
574	and $mtime being undef). Fractional times are supported if the underlying	692	and $mtime being undef). Fractional times are supported if the underlying
…		…
602	=item aio_truncate $fh_or_path, $offset, $callback->($status)	720	=item aio_truncate $fh_or_path, $offset, $callback->($status)
603		721
604	Works like truncate(2) or ftruncate(2).	722	Works like truncate(2) or ftruncate(2).
605		723
606		724
		725	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		726
		727	Allocates or frees disk space according to the C<$mode> argument. See the
		728	linux C<fallocate> documentation for details.
		729
		730	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		731	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		732	to deallocate a file range.
		733
		734	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		735	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		736	your L<fallocate(2)> manpage).
		737
		738	The file system block size used by C<fallocate> is presumably the
		739	C<f_bsize> returned by C<statvfs>.
		740
		741	If C<fallocate> isn't available or cannot be emulated (currently no
		742	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		743
		744
607	=item aio_chmod $fh_or_path, $mode, $callback->($status)	745	=item aio_chmod $fh_or_path, $mode, $callback->($status)
608		746
609	Works like perl's C<chmod> function.	747	Works like perl's C<chmod> function.
610		748
611		749
…		…
613		751
614	Asynchronously unlink (delete) a file and call the callback with the	752	Asynchronously unlink (delete) a file and call the callback with the
615	result code.	753	result code.
616		754
617		755
618	=item aio_mknod $path, $mode, $dev, $callback->($status)	756	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
619		757
620	[EXPERIMENTAL]	758	[EXPERIMENTAL]
621		759
622	Asynchronously create a device node (or fifo). See mknod(2).	760	Asynchronously create a device node (or fifo). See mknod(2).
623		761
624	The only (POSIX-) portable way of calling this function is:	762	The only (POSIX-) portable way of calling this function is:
625		763
626	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	764	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
627		765
628	See C<aio_stat> for info about some potentially helpful extra constants	766	See C<aio_stat> for info about some potentially helpful extra constants
629	and functions.	767	and functions.
630		768
631	=item aio_link $srcpath, $dstpath, $callback->($status)	769	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
638		776
639	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	777	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
640	the path C<$dstpath> and call the callback with the result code.	778	the path C<$dstpath> and call the callback with the result code.
641		779
642		780
643	=item aio_readlink $path, $callback->($link)	781	=item aio_readlink $pathname, $callback->($link)
644		782
645	Asynchronously read the symlink specified by C<$path> and pass it to	783	Asynchronously read the symlink specified by C<$path> and pass it to
646	the callback. If an error occurs, nothing or undef gets passed to the	784	the callback. If an error occurs, nothing or undef gets passed to the
647	callback.	785	callback.
648		786
649		787
650	=item aio_realpath $path, $callback->($path)	788	=item aio_realpath $pathname, $callback->($path)
651		789
652	Asynchronously make the path absolute and resolve any symlinks in	790	Asynchronously make the path absolute and resolve any symlinks in
653	C<$path>. The resulting path only consists of directories (Same as	791	C<$path>. The resulting path only consists of directories (same as
654	L<Cwd::realpath>).	792	L<Cwd::realpath>).
655		793
656	This request can be used to get the absolute path of the current working	794	This request can be used to get the absolute path of the current working
657	directory by passing it a path of F<.> (a single dot).	795	directory by passing it a path of F<.> (a single dot).
658		796
659		797
660	=item aio_rename $srcpath, $dstpath, $callback->($status)	798	=item aio_rename $srcpath, $dstpath, $callback->($status)
661		799
662	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	800	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
663	rename(2) and call the callback with the result code.	801	rename(2) and call the callback with the result code.
		802
		803	On systems that support the AIO::WD working directory abstraction
		804	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		805	of failing, C<rename> is called on the absolute path of C<$wd>.
664		806
665		807
666	=item aio_mkdir $pathname, $mode, $callback->($status)	808	=item aio_mkdir $pathname, $mode, $callback->($status)
667		809
668	Asynchronously mkdir (create) a directory and call the callback with	810	Asynchronously mkdir (create) a directory and call the callback with
…		…
673	=item aio_rmdir $pathname, $callback->($status)	815	=item aio_rmdir $pathname, $callback->($status)
674		816
675	Asynchronously rmdir (delete) a directory and call the callback with the	817	Asynchronously rmdir (delete) a directory and call the callback with the
676	result code.	818	result code.
677		819
		820	On systems that support the AIO::WD working directory abstraction
		821	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		822	C<rmdir> is called on the absolute path of C<$wd>.
		823
678		824
679	=item aio_readdir $pathname, $callback->($entries)	825	=item aio_readdir $pathname, $callback->($entries)
680		826
681	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	827	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
682	directory (i.e. opendir + readdir + closedir). The entries will not be	828	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
686	array-ref with the filenames.	832	array-ref with the filenames.
687		833
688		834
689	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	835	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
690		836
691	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	837	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
692	behaviour and output format. In case of an error, C<$entries> will be	838	tune behaviour and output format. In case of an error, C<$entries> will be
693	C<undef>.	839	C<undef>.
694		840
695	The flags are a combination of the following constants, ORed together (the	841	The flags are a combination of the following constants, ORed together (the
696	flags will also be passed to the callback, possibly modified):	842	flags will also be passed to the callback, possibly modified):
697		843
…		…
744		890
745	=item IO::AIO::READDIR_FOUND_UNKNOWN	891	=item IO::AIO::READDIR_FOUND_UNKNOWN
746		892
747	This flag should not be set when calling C<aio_readdirx>. Instead, it	893	This flag should not be set when calling C<aio_readdirx>. Instead, it
748	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	894	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
749	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	895	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
750	C<$type>'s are known, which can be used to speed up some algorithms.	896	C<$type>'s are known, which can be used to speed up some algorithms.
751		897
752	=back	898	=back
753		899
754		900
755	=item aio_load $path, $data, $callback->($status)	901	=item aio_load $pathname, $data, $callback->($status)
756		902
757	This is a composite request that tries to fully load the given file into	903	This is a composite request that tries to fully load the given file into
758	memory. Status is the same as with aio_read.	904	memory. Status is the same as with aio_read.
759		905
760	=cut	906	=cut
…		…
895	};	1041	};
896		1042
897	$grp	1043	$grp
898	}	1044	}
899		1045
900	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1046	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
901		1047
902	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1048	Scans a directory (similar to C<aio_readdir>) but additionally tries to
903	efficiently separate the entries of directory C<$path> into two sets of	1049	efficiently separate the entries of directory C<$path> into two sets of
904	names, directories you can recurse into (directories), and ones you cannot	1050	names, directories you can recurse into (directories), and ones you cannot
905	recurse into (everything else, including symlinks to directories).	1051	recurse into (everything else, including symlinks to directories).
…		…
936	Then entries will be sorted into likely directories a non-initial dot	1082	Then entries will be sorted into likely directories a non-initial dot
937	currently) and likely non-directories (see C<aio_readdirx>). Then every	1083	currently) and likely non-directories (see C<aio_readdirx>). Then every
938	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1084	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
939	in order of their inode numbers. If that succeeds, it assumes that the	1085	in order of their inode numbers. If that succeeds, it assumes that the
940	entry is a directory or a symlink to directory (which will be checked	1086	entry is a directory or a symlink to directory (which will be checked
941	seperately). This is often faster than stat'ing the entry itself because	1087	separately). This is often faster than stat'ing the entry itself because
942	filesystems might detect the type of the entry without reading the inode	1088	filesystems might detect the type of the entry without reading the inode
943	data (e.g. ext2fs filetype feature), even on systems that cannot return	1089	data (e.g. ext2fs filetype feature), even on systems that cannot return
944	the filetype information on readdir.	1090	the filetype information on readdir.
945		1091
946	If the known number of directories (link count - 2) has been reached, the	1092	If the known number of directories (link count - 2) has been reached, the
…		…
962		1108
963	my $grp = aio_group $cb;	1109	my $grp = aio_group $cb;
964		1110
965	$maxreq = 4 if $maxreq <= 0;	1111	$maxreq = 4 if $maxreq <= 0;
966		1112
967	# stat once	1113	# get a wd object
968	aioreq_pri $pri;	1114	aioreq_pri $pri;
969	add $grp aio_stat $path, sub {	1115	add $grp aio_wd $path, sub {
		1116	$_[0]
970	return $grp->result () if $_[0];	1117	or return $grp->result ();
971	my $now = time;
972	my $hash1 = join ":", (stat _)[0,1,3,7,9];
973		1118
974	# read the directory entries	1119	my $wd = [shift, "."];
		1120
		1121	# stat once
975	aioreq_pri $pri;	1122	aioreq_pri $pri;
976	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1123	add $grp aio_stat $wd, sub {
977	my $entries = shift
978	or return $grp->result ();	1124	return $grp->result () if $_[0];
		1125	my $now = time;
		1126	my $hash1 = join ":", (stat _)[0,1,3,7,9];
979		1127
980	# stat the dir another time	1128	# read the directory entries
981	aioreq_pri $pri;	1129	aioreq_pri $pri;
		1130	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1131	my $entries = shift
		1132	or return $grp->result ();
		1133
		1134	# stat the dir another time
		1135	aioreq_pri $pri;
982	add $grp aio_stat $path, sub {	1136	add $grp aio_stat $wd, sub {
983	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1137	my $hash2 = join ":", (stat _)[0,1,3,7,9];
984		1138
985	my $ndirs;	1139	my $ndirs;
986		1140
987	# take the slow route if anything looks fishy	1141	# take the slow route if anything looks fishy
988	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1142	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
989	$ndirs = -1;	1143	$ndirs = -1;
990	} else {	1144	} else {
991	# if nlink == 2, we are finished	1145	# if nlink == 2, we are finished
992	# for non-posix-fs's, we rely on nlink < 2	1146	# for non-posix-fs's, we rely on nlink < 2
993	$ndirs = (stat _)[3] - 2	1147	$ndirs = (stat _)[3] - 2
994	or return $grp->result ([], $entries);	1148	or return $grp->result ([], $entries);
995	}	1149	}
996		1150
997	my (@dirs, @nondirs);	1151	my (@dirs, @nondirs);
998		1152
999	my $statgrp = add $grp aio_group sub {	1153	my $statgrp = add $grp aio_group sub {
1000	$grp->result (\@dirs, \@nondirs);	1154	$grp->result (\@dirs, \@nondirs);
1001	};	1155	};
1002		1156
1003	limit $statgrp $maxreq;	1157	limit $statgrp $maxreq;
1004	feed $statgrp sub {	1158	feed $statgrp sub {
1005	return unless @$entries;	1159	return unless @$entries;
1006	my $entry = shift @$entries;	1160	my $entry = shift @$entries;
1007		1161
1008	aioreq_pri $pri;	1162	aioreq_pri $pri;
		1163	$wd->[1] = "$entry/.";
1009	add $statgrp aio_stat "$path/$entry/.", sub {	1164	add $statgrp aio_stat $wd, sub {
1010	if ($_[0] < 0) {	1165	if ($_[0] < 0) {
1011	push @nondirs, $entry;	1166	push @nondirs, $entry;
1012	} else {	1167	} else {
1013	# need to check for real directory	1168	# need to check for real directory
1014	aioreq_pri $pri;	1169	aioreq_pri $pri;
		1170	$wd->[1] = $entry;
1015	add $statgrp aio_lstat "$path/$entry", sub {	1171	add $statgrp aio_lstat $wd, sub {
1016	if (-d _) {	1172	if (-d _) {
1017	push @dirs, $entry;	1173	push @dirs, $entry;
1018		1174
1019	unless (--$ndirs) {	1175	unless (--$ndirs) {
1020	push @nondirs, @$entries;	1176	push @nondirs, @$entries;
1021	feed $statgrp;	1177	feed $statgrp;
		1178	}
		1179	} else {
		1180	push @nondirs, $entry;
1022	}	1181	}
1023	} else {
1024	push @nondirs, $entry;
1025	}	1182	}
1026	}	1183	}
1027	}	1184	};
1028	};	1185	};
1029	};	1186	};
1030	};	1187	};
1031	};	1188	};
1032	};	1189	};
1033		1190
1034	$grp	1191	$grp
1035	}	1192	}
1036		1193
1037	=item aio_rmtree $path, $callback->($status)	1194	=item aio_rmtree $pathname, $callback->($status)
1038		1195
1039	Delete a directory tree starting (and including) C<$path>, return the	1196	Delete a directory tree starting (and including) C<$path>, return the
1040	status of the final C<rmdir> only. This is a composite request that	1197	status of the final C<rmdir> only. This is a composite request that
1041	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1198	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1042	everything else.	1199	everything else.
1043		1200
1044	=cut	1201	=cut
1045		1202
…		…
1084	callback with the fdatasync result code.	1241	callback with the fdatasync result code.
1085		1242
1086	If this call isn't available because your OS lacks it or it couldn't be	1243	If this call isn't available because your OS lacks it or it couldn't be
1087	detected, it will be emulated by calling C<fsync> instead.	1244	detected, it will be emulated by calling C<fsync> instead.
1088		1245
		1246	=item aio_syncfs $fh, $callback->($status)
		1247
		1248	Asynchronously call the syncfs syscall to sync the filesystem associated
		1249	to the given filehandle and call the callback with the syncfs result
		1250	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1251	errno to C<ENOSYS> nevertheless.
		1252
1089	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1253	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1090		1254
1091	Sync the data portion of the file specified by C<$offset> and C<$length>	1255	Sync the data portion of the file specified by C<$offset> and C<$length>
1092	to disk (but NOT the metadata), by calling the Linux-specific	1256	to disk (but NOT the metadata), by calling the Linux-specific
1093	sync_file_range call. If sync_file_range is not available or it returns	1257	sync_file_range call. If sync_file_range is not available or it returns
…		…
1096	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1260	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1097	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1261	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1098	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1262	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1099	manpage for details.	1263	manpage for details.
1100		1264
1101	=item aio_pathsync $path, $callback->($status)	1265	=item aio_pathsync $pathname, $callback->($status)
1102		1266
1103	This request tries to open, fsync and close the given path. This is a	1267	This request tries to open, fsync and close the given path. This is a
1104	composite request intended to sync directories after directory operations	1268	composite request intended to sync directories after directory operations
1105	(E.g. rename). This might not work on all operating systems or have any	1269	(E.g. rename). This might not work on all operating systems or have any
1106	specific effect, but usually it makes sure that directory changes get	1270	specific effect, but usually it makes sure that directory changes get
…		…
1158		1322
1159	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1323	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1160	scalars.	1324	scalars.
1161		1325
1162	It touches (reads or writes) all memory pages in the specified	1326	It touches (reads or writes) all memory pages in the specified
1163	range inside the scalar. All caveats and parameters are the same	1327	range inside the scalar. All caveats and parameters are the same
1164	as for C<aio_msync>, above, except for flags, which must be either	1328	as for C<aio_msync>, above, except for flags, which must be either
1165	C<0> (which reads all pages and ensures they are instantiated) or	1329	C<0> (which reads all pages and ensures they are instantiated) or
1166	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1330	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1167	writing an octet from it, which dirties the page).	1331	writing an octet from it, which dirties the page).
1168		1332
1169	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1333	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1170		1334
1171	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1335	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1202	documented under L<MISCELLANEOUS FUNCTIONS>.	1366	documented under L<MISCELLANEOUS FUNCTIONS>.
1203		1367
1204	Example: asynchronously lock all current and future pages into memory.	1368	Example: asynchronously lock all current and future pages into memory.
1205		1369
1206	aio_mlockall IO::AIO::MCL_FUTURE;	1370	aio_mlockall IO::AIO::MCL_FUTURE;
		1371
		1372	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1373
		1374	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1375	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1376	the ioctl is not available on your OS, then this request will fail with
		1377	C<ENOSYS>.
		1378
		1379	C<$start> is the starting offset to query extents for, C<$length> is the
		1380	size of the range to query - if it is C<undef>, then the whole file will
		1381	be queried.
		1382
		1383	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1384	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1385	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1386	the data portion.
		1387
		1388	C<$count> is the maximum number of extent records to return. If it is
		1389	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1390	case, if it is C<0>, then the callback receives the number of extents
		1391	instead of the extents themselves (which is unreliable, see below).
		1392
		1393	If an error occurs, the callback receives no arguments. The special
		1394	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1395
		1396	Otherwise, the callback receives an array reference with extent
		1397	structures. Each extent structure is an array reference itself, with the
		1398	following members:
		1399
		1400	[$logical, $physical, $length, $flags]
		1401
		1402	Flags is any combination of the following flag values (typically either C<0>
		1403	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1404
		1405	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1406	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1407	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1408	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1409	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1410	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1411
		1412	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1413	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1414	it to return all extents of a range for files with large number of
		1415	extents. The code works around all these issues if C<$count> is undef.
1207		1416
1208	=item aio_group $callback->(...)	1417	=item aio_group $callback->(...)
1209		1418
1210	This is a very special aio request: Instead of doing something, it is a	1419	This is a very special aio request: Instead of doing something, it is a
1211	container for other aio requests, which is useful if you want to bundle	1420	container for other aio requests, which is useful if you want to bundle
…		…
1248	like sleep and file handle readable/writable, the overhead this creates is	1457	like sleep and file handle readable/writable, the overhead this creates is
1249	immense (it blocks a thread for a long time) so do not use this function	1458	immense (it blocks a thread for a long time) so do not use this function
1250	except to put your application under artificial I/O pressure.	1459	except to put your application under artificial I/O pressure.
1251		1460
1252	=back	1461	=back
		1462
		1463
		1464	=head2 IO::AIO::WD - multiple working directories
		1465
		1466	Your process only has one current working directory, which is used by all
		1467	threads. This makes it hard to use relative paths (some other component
		1468	could call C<chdir> at any time, and it is hard to control when the path
		1469	will be used by IO::AIO).
		1470
		1471	One solution for this is to always use absolute paths. This usually works,
		1472	but can be quite slow (the kernel has to walk the whole path on every
		1473	access), and can also be a hassle to implement.
		1474
		1475	Newer POSIX systems have a number of functions (openat, fdopendir,
		1476	futimensat and so on) that make it possible to specify working directories
		1477	per operation.
		1478
		1479	For portability, and because the clowns who "designed", or shall I write,
		1480	perpetrated this new interface were obviously half-drunk, this abstraction
		1481	cannot be perfect, though.
		1482
		1483	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1484	object. This object stores the canonicalised, absolute version of the
		1485	path, and on systems that allow it, also a directory file descriptor.
		1486
		1487	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1488	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1489	object and a pathname instead (or the IO::AIO::WD object alone, which
		1490	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1491	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1492	to that IO::AIO::WD object.
		1493
		1494	For example, to get a wd object for F</etc> and then stat F<passwd>
		1495	inside, you would write:
		1496
		1497	aio_wd "/etc", sub {
		1498	my $etcdir = shift;
		1499
		1500	# although $etcdir can be undef on error, there is generally no reason
		1501	# to check for errors here, as aio_stat will fail with ENOENT
		1502	# when $etcdir is undef.
		1503
		1504	aio_stat [$etcdir, "passwd"], sub {
		1505	# yay
		1506	};
		1507	};
		1508
		1509	The fact that C<aio_wd> is a request and not a normal function shows that
		1510	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1511	which is why it is done asynchronously.
		1512
		1513	To stat the directory obtained with C<aio_wd> above, one could write
		1514	either of the following three request calls:
		1515
		1516	aio_lstat "/etc" , sub { ... # pathname as normal string
		1517	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1518	aio_lstat $wd , sub { ... # shorthand for the previous
		1519
		1520	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1521	object and the pathname string, so you could write the following without
		1522	causing any issues due to C<$path> getting reused:
		1523
		1524	my $path = [$wd, undef];
		1525
		1526	for my $name (qw(abc def ghi)) {
		1527	$path->[1] = $name;
		1528	aio_stat $path, sub {
		1529	# ...
		1530	};
		1531	}
		1532
		1533	There are some caveats: when directories get renamed (or deleted), the
		1534	pathname string doesn't change, so will point to the new directory (or
		1535	nowhere at all), while the directory fd, if available on the system,
		1536	will still point to the original directory. Most functions accepting a
		1537	pathname will use the directory fd on newer systems, and the string on
		1538	older systems. Some functions (such as realpath) will always rely on the
		1539	string form of the pathname.
		1540
		1541	So this functionality is mainly useful to get some protection against
		1542	C<chdir>, to easily get an absolute path out of a relative path for future
		1543	reference, and to speed up doing many operations in the same directory
		1544	(e.g. when stat'ing all files in a directory).
		1545
		1546	The following functions implement this working directory abstraction:
		1547
		1548	=over 4
		1549
		1550	=item aio_wd $pathname, $callback->($wd)
		1551
		1552	Asynchonously canonicalise the given pathname and convert it to an
		1553	IO::AIO::WD object representing it. If possible and supported on the
		1554	system, also open a directory fd to speed up pathname resolution relative
		1555	to this working directory.
		1556
		1557	If something goes wrong, then C<undef> is passwd to the callback instead
		1558	of a working directory object and C<$!> is set appropriately. Since
		1559	passing C<undef> as working directory component of a pathname fails the
		1560	request with C<ENOENT>, there is often no need for error checking in the
		1561	C<aio_wd> callback, as future requests using the value will fail in the
		1562	expected way.
		1563
		1564	=item IO::AIO::CWD
		1565
		1566	This is a compiletime constant (object) that represents the process
		1567	current working directory.
		1568
		1569	Specifying this object as working directory object for a pathname is as if
		1570	the pathname would be specified directly, without a directory object. For
		1571	example, these calls are functionally identical:
		1572
		1573	aio_stat "somefile", sub { ... };
		1574	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1575
		1576	=back
		1577
		1578	To recover the path associated with an IO::AIO::WD object, you can use
		1579	C<aio_realpath>:
		1580
		1581	aio_realpath $wd, sub {
		1582	warn "path is $_[0]\n";
		1583	};
		1584
		1585	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1586	sometimes, fall back to using an absolue path.
1253		1587
1254	=head2 IO::AIO::REQ CLASS	1588	=head2 IO::AIO::REQ CLASS
1255		1589
1256	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
1257	called in non-void context.	1591	called in non-void context.
…		…
1375		1709
1376	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
1377	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,
1378	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,
1379	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,
1380	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>
1381	delaying any later requests for a long time.	1715	requests, delaying any later requests for a long time.
1382		1716
1383	To avoid this, and allow incremental generation of requests, you can	1717	To avoid this, and allow incremental generation of requests, you can
1384	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
1385	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>,
1386	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
…		…
1435		1769
1436	See C<poll_cb> for an example.	1770	See C<poll_cb> for an example.
1437		1771
1438	=item IO::AIO::poll_cb	1772	=item IO::AIO::poll_cb
1439		1773
1440	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
1441	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
1442	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
1443	reason. Returns immediately when no events are outstanding. The amount of	1780	reason. Returns immediately when no events are outstanding. The amount
1444	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>,
1445	C<IO::AIO::max_poll_time>.	1782	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1446		1783
1447	If not all requests were processed for whatever reason, the filehandle	1784	If not all requests were processed for whatever reason, the poll file
1448	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
1449	do anything special to have it called later.	1786	don't have to do anything special to have it called later.
1450		1787
1451	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
1452	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
1453	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
1454	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
…		…
1463	poll => 'r', async => 1,	1800	poll => 'r', async => 1,
1464	cb => \&IO::AIO::poll_cb);	1801	cb => \&IO::AIO::poll_cb);
1465		1802
1466	=item IO::AIO::poll_wait	1803	=item IO::AIO::poll_wait
1467		1804
1468	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
1469	phase, wait till the result filehandle becomes ready for reading (simply	1806	requests are outstanding anymore.
1470	does a C<select> on the filehandle. This is useful if you want to	1807
1471	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.
1472		1810
1473	See C<nreqs> for an example.	1811	See C<nreqs> for an example.
1474		1812
1475	=item IO::AIO::poll	1813	=item IO::AIO::poll
1476		1814
…		…
1597		1935
1598	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
1599	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
1600	use an C<aio_group> together with a feed callback.	1938	use an C<aio_group> together with a feed callback.
1601		1939
1602	It's main use is in scripts without an event loop - when you want to stat	1940	Its main use is in scripts without an event loop - when you want to stat
1603	a lot of files, you can write somehting like this:	1941	a lot of files, you can write somehting like this:
1604		1942
1605	IO::AIO::max_outstanding 32;	1943	IO::AIO::max_outstanding 32;
1606		1944
1607	for my $path (...) {	1945	for my $path (...) {
…		…
1647		1985
1648	=back	1986	=back
1649		1987
1650	=head3 MISCELLANEOUS FUNCTIONS	1988	=head3 MISCELLANEOUS FUNCTIONS
1651		1989
1652	IO::AIO implements some functions that might be useful, but are not	1990	IO::AIO implements some functions that are useful when you want to use
1653	asynchronous.	1991	some "Advanced I/O" function not available to in Perl, without going the
		1992	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		1993	counterpart.
1654		1994
1655	=over 4	1995	=over 4
1656		1996
1657	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	1997	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1658		1998
…		…
1665		2005
1666	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2006	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1667		2007
1668	Simply calls the C<posix_fadvise> function (see its	2008	Simply calls the C<posix_fadvise> function (see its
1669	manpage for details). The following advice constants are	2009	manpage for details). The following advice constants are
1670	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2010	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1671	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2011	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1672	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2012	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1673		2013
1674	On systems that do not implement C<posix_fadvise>, this function returns	2014	On systems that do not implement C<posix_fadvise>, this function returns
1675	ENOSYS, otherwise the return value of C<posix_fadvise>.	2015	ENOSYS, otherwise the return value of C<posix_fadvise>.
1676		2016
1677	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2017	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1678		2018
1679	Simply calls the C<posix_madvise> function (see its	2019	Simply calls the C<posix_madvise> function (see its
1680	manpage for details). The following advice constants are	2020	manpage for details). The following advice constants are
1681	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2021	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1682	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2022	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1683		2023
1684	On systems that do not implement C<posix_madvise>, this function returns	2024	On systems that do not implement C<posix_madvise>, this function returns
1685	ENOSYS, otherwise the return value of C<posix_madvise>.	2025	ENOSYS, otherwise the return value of C<posix_madvise>.
1686		2026
1687	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2027	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1688		2028
1689	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2029	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1690	$scalar (see its manpage for details). The following protect	2030	$scalar (see its manpage for details). The following protect
1691	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2031	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1692	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2032	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1693		2033
1694	On systems that do not implement C<mprotect>, this function returns	2034	On systems that do not implement C<mprotect>, this function returns
1695	ENOSYS, otherwise the return value of C<mprotect>.	2035	ENOSYS, otherwise the return value of C<mprotect>.
1696		2036
1697	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2037	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1698		2038
1699	Memory-maps a file (or anonymous memory range) and attaches it to the	2039	Memory-maps a file (or anonymous memory range) and attaches it to the
1700	given C<$scalar>, which will act like a string scalar.	2040	given C<$scalar>, which will act like a string scalar. Returns true on
		2041	success, and false otherwise.
1701		2042
1702	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2043	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1703	change the string length, and most read-only operations such as copying it	2044	change the string length, and most read-only operations such as copying it
1704	or searching it with regexes and so on.	2045	or searching it with regexes and so on.
1705		2046
…		…
1758	Calls the C<munlockall> function.	2099	Calls the C<munlockall> function.
1759		2100
1760	On systems that do not implement C<munlockall>, this function returns	2101	On systems that do not implement C<munlockall>, this function returns
1761	ENOSYS, otherwise the return value of C<munlockall>.	2102	ENOSYS, otherwise the return value of C<munlockall>.
1762		2103
		2104	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2105
		2106	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2107	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2108	should be the file offset.
		2109
		2110	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2111	silently corrupt the data in this case.
		2112
		2113	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2114	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2115	C<IO::AIO::SPLICE_F_GIFT>.
		2116
		2117	See the C<splice(2)> manpage for details.
		2118
		2119	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2120
		2121	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2122	description for C<IO::AIO::splice> above for details.
		2123
		2124	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2125
		2126	Attempts to query or change the pipe buffer size. Obviously works only
		2127	on pipes, and currently works only on GNU/Linux systems, and fails with
		2128	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2129	size on other systems, drop me a note.
		2130
1763	=back	2131	=back
1764		2132
1765	=cut	2133	=cut
1766		2134
1767	min_parallel 8;	2135	min_parallel 8;
…		…
1804	=head2 FORK BEHAVIOUR	2172	=head2 FORK BEHAVIOUR
1805		2173
1806	Usage of pthreads in a program changes the semantics of fork	2174	Usage of pthreads in a program changes the semantics of fork
1807	considerably. Specifically, only async-safe functions can be called after	2175	considerably. Specifically, only async-safe functions can be called after
1808	fork. Perl doesn't know about this, so in general, you cannot call fork	2176	fork. Perl doesn't know about this, so in general, you cannot call fork
1809	with defined behaviour in perl. IO::AIO uses pthreads, so this applies,	2177	with defined behaviour in perl if pthreads are involved. IO::AIO uses
1810	but many other extensions and (for inexplicable reasons) perl itself often	2178	pthreads, so this applies, but many other extensions and (for inexplicable
1811	is linked against pthreads, so this limitation applies.	2179	reasons) perl itself often is linked against pthreads, so this limitation
		2180	applies to quite a lot of perls.
1812		2181
1813	Some operating systems have extensions that allow safe use of fork, and	2182	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1814	this module should do "the right thing" on those, and tries on others. At	2183	only works in the process that loaded it. Forking is fully supported, but
1815	the time of this writing (2011) only GNU/Linux supports these extensions	2184	using IO::AIO in the child is not.
1816	to POSIX.	2185
		2186	You might get around by not I<using> IO::AIO before (or after)
		2187	forking. You could also try to call the L<IO::AIO::reinit> function in the
		2188	child:
		2189
		2190	=over 4
		2191
		2192	=item IO::AIO::reinit
		2193
		2194	Abandons all current requests and I/O threads and simply reinitialises all
		2195	data structures. This is not an operation supported by any standards, but
		2196	happens to work on GNU/Linux and some newer BSD systems.
		2197
		2198	The only reasonable use for this function is to call it after forking, if
		2199	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2200	the process will result in undefined behaviour. Calling it at any time
		2201	will also result in any undefined (by POSIX) behaviour.
		2202
		2203	=back
1817		2204
1818	=head2 MEMORY USAGE	2205	=head2 MEMORY USAGE
1819		2206
1820	Per-request usage:	2207	Per-request usage:
1821		2208

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs. Revision 1.252 by root, Sat Jun 13 00:06:13 2015 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs.
Revision 1.252 by root, Sat Jun 13 00:06:13 2015 UTC