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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs.
Revision 1.258 by root, Thu Jan 21 23:04:46 2016 UTC

…		…
68	=head2 EXAMPLE	68	=head2 EXAMPLE
69		69
70	This is a simple example that uses the EV module and loads	70	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
72		72
73	use Fcntl;
74	use EV;	73	use EV;
75	use IO::AIO;	74	use IO::AIO;
76		75
77	# register the IO::AIO callback with EV	76	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	77	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		94
96	# file contents now in $contents	95	# file contents now in $contents
97	print $contents;	96	print $contents;
98		97
99	# exit event loop and program	98	# exit event loop and program
100	EV::unloop;	99	EV::break;
101	};	100	};
102	};	101	};
103		102
104	# possibly queue up other requests, or open GUI windows,	103	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	104	# check for sockets etc. etc.
106		105
107	# process events as long as there are some:	106	# process events as long as there are some:
108	EV::loop;	107	EV::run;
109		108
110	=head1 REQUEST ANATOMY AND LIFETIME	109	=head1 REQUEST ANATOMY AND LIFETIME
111		110
112	Every C<aio_*> function creates a request. which is a C data structure not	111	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	112	directly visible to Perl.
…		…
168	use common::sense;	167	use common::sense;
169		168
170	use base 'Exporter';	169	use base 'Exporter';
171		170
172	BEGIN {	171	BEGIN {
173	our $VERSION = '4.0';	172	our $VERSION = 4.33;
174		173
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	174	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	175	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync	176	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178	aio_fsync aio_syncfs 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
…		…
202		201
203	=head1 FUNCTIONS	202	=head1 FUNCTIONS
204		203
205	=head2 QUICK OVERVIEW	204	=head2 QUICK OVERVIEW
206		205
207	This section simply lists the prototypes of the most important functions	206	This section simply lists the prototypes most of the functions for
208	for quick reference. See the following sections for function-by-function	207	quick reference. See the following sections for function-by-function
209	documentation.	208	documentation.
210		209
211	aio_wd $pathname, $callback->($wd)	210	aio_wd $pathname, $callback->($wd)
212	aio_open $pathname, $flags, $mode, $callback->($fh)	211	aio_open $pathname, $flags, $mode, $callback->($fh)
213	aio_close $fh, $callback->($status)	212	aio_close $fh, $callback->($status)
		213	aio_seek $fh,$offset,$whence, $callback->($offs)
214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217	aio_readahead $fh,$offset,$length, $callback->($retval)	217	aio_readahead $fh,$offset,$length, $callback->($retval)
218	aio_stat $fh_or_path, $callback->($status)	218	aio_stat $fh_or_path, $callback->($status)
219	aio_lstat $fh, $callback->($status)	219	aio_lstat $fh, $callback->($status)
220	aio_statvfs $fh_or_path, $callback->($statvfs)	220	aio_statvfs $fh_or_path, $callback->($statvfs)
221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		223	aio_chmod $fh_or_path, $mode, $callback->($status)
223	aio_truncate $fh_or_path, $offset, $callback->($status)	224	aio_truncate $fh_or_path, $offset, $callback->($status)
224	aio_chmod $fh_or_path, $mode, $callback->($status)	225	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		226	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225	aio_unlink $pathname, $callback->($status)	227	aio_unlink $pathname, $callback->($status)
226	aio_mknod $path, $mode, $dev, $callback->($status)	228	aio_mknod $pathname, $mode, $dev, $callback->($status)
227	aio_link $srcpath, $dstpath, $callback->($status)	229	aio_link $srcpath, $dstpath, $callback->($status)
228	aio_symlink $srcpath, $dstpath, $callback->($status)	230	aio_symlink $srcpath, $dstpath, $callback->($status)
229	aio_readlink $path, $callback->($link)	231	aio_readlink $pathname, $callback->($link)
230	aio_realpath $path, $callback->($link)	232	aio_realpath $pathname, $callback->($path)
231	aio_rename $srcpath, $dstpath, $callback->($status)	233	aio_rename $srcpath, $dstpath, $callback->($status)
232	aio_mkdir $pathname, $mode, $callback->($status)	234	aio_mkdir $pathname, $mode, $callback->($status)
233	aio_rmdir $pathname, $callback->($status)	235	aio_rmdir $pathname, $callback->($status)
234	aio_readdir $pathname, $callback->($entries)	236	aio_readdir $pathname, $callback->($entries)
235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	239	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		240	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238	aio_load $path, $data, $callback->($status)	241	aio_load $pathname, $data, $callback->($status)
239	aio_copy $srcpath, $dstpath, $callback->($status)	242	aio_copy $srcpath, $dstpath, $callback->($status)
240	aio_move $srcpath, $dstpath, $callback->($status)	243	aio_move $srcpath, $dstpath, $callback->($status)
241	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
242	aio_rmtree $path, $callback->($status)	244	aio_rmtree $pathname, $callback->($status)
243	aio_sync $callback->($status)	245	aio_sync $callback->($status)
244	aio_syncfs $fh, $callback->($status)	246	aio_syncfs $fh, $callback->($status)
245	aio_fsync $fh, $callback->($status)	247	aio_fsync $fh, $callback->($status)
246	aio_fdatasync $fh, $callback->($status)	248	aio_fdatasync $fh, $callback->($status)
247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	249	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248	aio_pathsync $path, $callback->($status)	250	aio_pathsync $pathname, $callback->($status)
249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	251	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	252	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	253	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252	aio_mlockall $flags, $callback->($status)	254	aio_mlockall $flags, $callback->($status)
253	aio_group $callback->(...)	255	aio_group $callback->(...)
…		…
271	IO::AIO::nready	273	IO::AIO::nready
272	IO::AIO::npending	274	IO::AIO::npending
273		275
274	IO::AIO::sendfile $ofh, $ifh, $offset, $count	276	IO::AIO::sendfile $ofh, $ifh, $offset, $count
275	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
276	IO::AIO::madvise $scalar, $offset, $length, $advice	280	IO::AIO::madvise $scalar, $offset, $length, $advice
277	IO::AIO::mprotect $scalar, $offset, $length, $protect	281	IO::AIO::mprotect $scalar, $offset, $length, $protect
278	IO::AIO::munlock $scalar, $offset = 0, $length = undef	282	IO::AIO::munlock $scalar, $offset = 0, $length = undef
279	IO::AIO::munlockall	283	IO::AIO::munlockall
280		284
281	=head2 AIO REQUEST FUNCTIONS	285	=head2 API NOTES
282		286
283	All the C<aio_*> calls are more or less thin wrappers around the syscall	287	All the C<aio_*> calls are more or less thin wrappers around the syscall
284	with the same name (sans C<aio_>). The arguments are similar or identical,	288	with the same name (sans C<aio_>). The arguments are similar or identical,
285	and they all accept an additional (and optional) C<$callback> argument	289	and they all accept an additional (and optional) C<$callback> argument
286	which must be a code reference. This code reference will get called with	290	which must be a code reference. This code reference will be called after
287	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	291	the syscall has been executed in an asynchronous fashion. The results
288	perl, which usually delivers "false") as its sole argument after the given	292	of the request will be passed as arguments to the callback (and, if an
289	syscall has been executed asynchronously.	293	error occured, in C<$!>) - 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>.
290		299
291	All functions expecting a filehandle keep a copy of the filehandle	300	All functions expecting a filehandle keep a copy of the filehandle
292	internally until the request has finished.	301	internally until the request has finished.
293		302
294	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
295	further manipulation of those requests while they are in-flight.	304	further manipulation of those requests while they are in-flight.
296		305
297	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
298	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
299	request is being executed, the current working directory could have	308	current working directory could have changed. Alternatively, you can
300	changed. Alternatively, you can make sure that you never change the	309	make sure that you never change the current working directory anywhere
301	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
302	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.
303		314
304	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
305	in filenames you got from outside (command line, readdir etc.) without	316	in filenames you got from outside (command line, readdir etc.) without
306	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	317	tinkering, b) are in your native filesystem encoding, c) use the Encode
307	your pathnames to the locale (or other) encoding in effect in the user	318	module and encode your pathnames to the locale (or other) encoding in
308	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	319	effect in the user environment, d) use Glib::filename_from_unicode on
309	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.
310		322
311	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
312	handles correctly whether it is set or not.	324	handles correctly whether it is set or not.
		325
		326	=head2 AIO REQUEST FUNCTIONS
313		327
314	=over 4	328	=over 4
315		329
316	=item $prev_pri = aioreq_pri [$pri]	330	=item $prev_pri = aioreq_pri [$pri]
317		331
…		…
347		361
348		362
349	=item aio_open $pathname, $flags, $mode, $callback->($fh)	363	=item aio_open $pathname, $flags, $mode, $callback->($fh)
350		364
351	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
352	created filehandle for the file.	366	created filehandle for the file (or C<undef> in case of an error).
353		367
354	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,
355	for an explanation.	369	for an explanation.
356		370
357	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
…		…
380	following POSIX and non-POSIX constants are available (missing ones on	394	following POSIX and non-POSIX constants are available (missing ones on
381	your system are, as usual, C<0>):	395	your system are, as usual, C<0>):
382		396
383	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	397	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
384	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	398	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
385	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	399	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
386		400
387		401
388	=item aio_close $fh, $callback->($status)	402	=item aio_close $fh, $callback->($status)
389		403
390	Asynchronously close a file and call the callback with the result	404	Asynchronously close a file and call the callback with the result
…		…
399		413
400	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
401	free for reuse until the perl filehandle is closed.	415	free for reuse until the perl filehandle is closed.
402		416
403	=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".
404		438
405	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	439	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
406		440
407	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	441	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
408		442
…		…
568	namemax => 255,	602	namemax => 255,
569	frsize => 1024,	603	frsize => 1024,
570	fsid => 1810	604	fsid => 1810
571	}	605	}
572		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/ext4
		632	0x0000ef51 ext2
		633	0xf2f52010 f2fs
		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	0x00c0ffee hostfs
		643	0x958458f6 hugetlbfs
		644	0x2bad1dea inotifyfs
		645	0x00009660 isofs
		646	0x000072b6 jffs2
		647	0x3153464a jfs
		648	0x6b414653 k-afs
		649	0x0bd00bd0 lustre
		650	0x0000137f minix
		651	0x0000138f minix 30 char names
		652	0x00002468 minix v2
		653	0x00002478 minix v2 30 char names
		654	0x00004d5a minix v3
		655	0x19800202 mqueue
		656	0x00004d44 msdos
		657	0x0000564c novell
		658	0x00006969 nfs
		659	0x6e667364 nfsd
		660	0x00003434 nilfs
		661	0x5346544e ntfs
		662	0x00009fa1 openprom
		663	0x7461636F ocfs2
		664	0x00009fa0 proc
		665	0x6165676c pstorefs
		666	0x0000002f qnx4
		667	0x68191122 qnx6
		668	0x858458f6 ramfs
		669	0x52654973 reiserfs
		670	0x00007275 romfs
		671	0x67596969 rpc_pipefs
		672	0x73636673 securityfs
		673	0xf97cff8c selinux
		674	0x0000517b smb
		675	0x534f434b sockfs
		676	0x73717368 squashfs
		677	0x62656572 sysfs
		678	0x012ff7b6 sysv2
		679	0x012ff7b5 sysv4
		680	0x01021994 tmpfs
		681	0x15013346 udf
		682	0x00011954 ufs
		683	0x54190100 ufs byteswapped
		684	0x00009fa2 usbdevfs
		685	0x01021997 v9fs
		686	0xa501fcf5 vxfs
		687	0xabba1974 xenfs
		688	0x012ff7b4 xenix
		689	0x58465342 xfs
		690	0x012fd16d xia
573		691
574	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	692	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
575		693
576	Works like perl's C<utime> function (including the special case of $atime	694	Works like perl's C<utime> function (including the special case of $atime
577	and $mtime being undef). Fractional times are supported if the underlying	695	and $mtime being undef). Fractional times are supported if the underlying
…		…
605	=item aio_truncate $fh_or_path, $offset, $callback->($status)	723	=item aio_truncate $fh_or_path, $offset, $callback->($status)
606		724
607	Works like truncate(2) or ftruncate(2).	725	Works like truncate(2) or ftruncate(2).
608		726
609		727
		728	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		729
		730	Allocates or frees disk space according to the C<$mode> argument. See the
		731	linux C<fallocate> documentation for details.
		732
		733	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		734	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		735	to deallocate a file range.
		736
		737	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		738	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		739	your L<fallocate(2)> manpage).
		740
		741	The file system block size used by C<fallocate> is presumably the
		742	C<f_bsize> returned by C<statvfs>.
		743
		744	If C<fallocate> isn't available or cannot be emulated (currently no
		745	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		746
		747
610	=item aio_chmod $fh_or_path, $mode, $callback->($status)	748	=item aio_chmod $fh_or_path, $mode, $callback->($status)
611		749
612	Works like perl's C<chmod> function.	750	Works like perl's C<chmod> function.
613		751
614		752
…		…
616		754
617	Asynchronously unlink (delete) a file and call the callback with the	755	Asynchronously unlink (delete) a file and call the callback with the
618	result code.	756	result code.
619		757
620		758
621	=item aio_mknod $path, $mode, $dev, $callback->($status)	759	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
622		760
623	[EXPERIMENTAL]	761	[EXPERIMENTAL]
624		762
625	Asynchronously create a device node (or fifo). See mknod(2).	763	Asynchronously create a device node (or fifo). See mknod(2).
626		764
627	The only (POSIX-) portable way of calling this function is:	765	The only (POSIX-) portable way of calling this function is:
628		766
629	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	767	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
630		768
631	See C<aio_stat> for info about some potentially helpful extra constants	769	See C<aio_stat> for info about some potentially helpful extra constants
632	and functions.	770	and functions.
633		771
634	=item aio_link $srcpath, $dstpath, $callback->($status)	772	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
641		779
642	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	780	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
643	the path C<$dstpath> and call the callback with the result code.	781	the path C<$dstpath> and call the callback with the result code.
644		782
645		783
646	=item aio_readlink $path, $callback->($link)	784	=item aio_readlink $pathname, $callback->($link)
647		785
648	Asynchronously read the symlink specified by C<$path> and pass it to	786	Asynchronously read the symlink specified by C<$path> and pass it to
649	the callback. If an error occurs, nothing or undef gets passed to the	787	the callback. If an error occurs, nothing or undef gets passed to the
650	callback.	788	callback.
651		789
652		790
653	=item aio_realpath $path, $callback->($path)	791	=item aio_realpath $pathname, $callback->($path)
654		792
655	Asynchronously make the path absolute and resolve any symlinks in	793	Asynchronously make the path absolute and resolve any symlinks in
656	C<$path>. The resulting path only consists of directories (Same as	794	C<$path>. The resulting path only consists of directories (same as
657	L<Cwd::realpath>).	795	L<Cwd::realpath>).
658		796
659	This request can be used to get the absolute path of the current working	797	This request can be used to get the absolute path of the current working
660	directory by passing it a path of F<.> (a single dot).	798	directory by passing it a path of F<.> (a single dot).
661		799
662		800
663	=item aio_rename $srcpath, $dstpath, $callback->($status)	801	=item aio_rename $srcpath, $dstpath, $callback->($status)
664		802
665	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	803	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
666	rename(2) and call the callback with the result code.	804	rename(2) and call the callback with the result code.
		805
		806	On systems that support the AIO::WD working directory abstraction
		807	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		808	of failing, C<rename> is called on the absolute path of C<$wd>.
667		809
668		810
669	=item aio_mkdir $pathname, $mode, $callback->($status)	811	=item aio_mkdir $pathname, $mode, $callback->($status)
670		812
671	Asynchronously mkdir (create) a directory and call the callback with	813	Asynchronously mkdir (create) a directory and call the callback with
…		…
675		817
676	=item aio_rmdir $pathname, $callback->($status)	818	=item aio_rmdir $pathname, $callback->($status)
677		819
678	Asynchronously rmdir (delete) a directory and call the callback with the	820	Asynchronously rmdir (delete) a directory and call the callback with the
679	result code.	821	result code.
		822
		823	On systems that support the AIO::WD working directory abstraction
		824	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		825	C<rmdir> is called on the absolute path of C<$wd>.
680		826
681		827
682	=item aio_readdir $pathname, $callback->($entries)	828	=item aio_readdir $pathname, $callback->($entries)
683		829
684	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	830	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
…		…
753	C<$type>'s are known, which can be used to speed up some algorithms.	899	C<$type>'s are known, which can be used to speed up some algorithms.
754		900
755	=back	901	=back
756		902
757		903
758	=item aio_load $path, $data, $callback->($status)	904	=item aio_load $pathname, $data, $callback->($status)
759		905
760	This is a composite request that tries to fully load the given file into	906	This is a composite request that tries to fully load the given file into
761	memory. Status is the same as with aio_read.	907	memory. Status is the same as with aio_read.
762		908
763	=cut	909	=cut
…		…
898	};	1044	};
899		1045
900	$grp	1046	$grp
901	}	1047	}
902		1048
903	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1049	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
904		1050
905	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1051	Scans a directory (similar to C<aio_readdir>) but additionally tries to
906	efficiently separate the entries of directory C<$path> into two sets of	1052	efficiently separate the entries of directory C<$path> into two sets of
907	names, directories you can recurse into (directories), and ones you cannot	1053	names, directories you can recurse into (directories), and ones you cannot
908	recurse into (everything else, including symlinks to directories).	1054	recurse into (everything else, including symlinks to directories).
…		…
965		1111
966	my $grp = aio_group $cb;	1112	my $grp = aio_group $cb;
967		1113
968	$maxreq = 4 if $maxreq <= 0;	1114	$maxreq = 4 if $maxreq <= 0;
969		1115
970	# stat once	1116	# get a wd object
971	aioreq_pri $pri;	1117	aioreq_pri $pri;
972	add $grp aio_stat $path, sub {	1118	add $grp aio_wd $path, sub {
		1119	$_[0]
973	return $grp->result () if $_[0];	1120	or return $grp->result ();
974	my $now = time;
975	my $hash1 = join ":", (stat _)[0,1,3,7,9];
976		1121
977	# read the directory entries	1122	my $wd = [shift, "."];
		1123
		1124	# stat once
978	aioreq_pri $pri;	1125	aioreq_pri $pri;
979	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1126	add $grp aio_stat $wd, sub {
980	my $entries = shift
981	or return $grp->result ();	1127	return $grp->result () if $_[0];
		1128	my $now = time;
		1129	my $hash1 = join ":", (stat _)[0,1,3,7,9];
982		1130
983	# stat the dir another time	1131	# read the directory entries
984	aioreq_pri $pri;	1132	aioreq_pri $pri;
		1133	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1134	my $entries = shift
		1135	or return $grp->result ();
		1136
		1137	# stat the dir another time
		1138	aioreq_pri $pri;
985	add $grp aio_stat $path, sub {	1139	add $grp aio_stat $wd, sub {
986	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1140	my $hash2 = join ":", (stat _)[0,1,3,7,9];
987		1141
988	my $ndirs;	1142	my $ndirs;
989		1143
990	# take the slow route if anything looks fishy	1144	# take the slow route if anything looks fishy
991	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1145	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
992	$ndirs = -1;	1146	$ndirs = -1;
993	} else {	1147	} else {
994	# if nlink == 2, we are finished	1148	# if nlink == 2, we are finished
995	# for non-posix-fs's, we rely on nlink < 2	1149	# for non-posix-fs's, we rely on nlink < 2
996	$ndirs = (stat _)[3] - 2	1150	$ndirs = (stat _)[3] - 2
997	or return $grp->result ([], $entries);	1151	or return $grp->result ([], $entries);
998	}	1152	}
999		1153
1000	my (@dirs, @nondirs);	1154	my (@dirs, @nondirs);
1001		1155
1002	my $statgrp = add $grp aio_group sub {	1156	my $statgrp = add $grp aio_group sub {
1003	$grp->result (\@dirs, \@nondirs);	1157	$grp->result (\@dirs, \@nondirs);
1004	};	1158	};
1005		1159
1006	limit $statgrp $maxreq;	1160	limit $statgrp $maxreq;
1007	feed $statgrp sub {	1161	feed $statgrp sub {
1008	return unless @$entries;	1162	return unless @$entries;
1009	my $entry = shift @$entries;	1163	my $entry = shift @$entries;
1010		1164
1011	aioreq_pri $pri;	1165	aioreq_pri $pri;
		1166	$wd->[1] = "$entry/.";
1012	add $statgrp aio_stat "$path/$entry/.", sub {	1167	add $statgrp aio_stat $wd, sub {
1013	if ($_[0] < 0) {	1168	if ($_[0] < 0) {
1014	push @nondirs, $entry;	1169	push @nondirs, $entry;
1015	} else {	1170	} else {
1016	# need to check for real directory	1171	# need to check for real directory
1017	aioreq_pri $pri;	1172	aioreq_pri $pri;
		1173	$wd->[1] = $entry;
1018	add $statgrp aio_lstat "$path/$entry", sub {	1174	add $statgrp aio_lstat $wd, sub {
1019	if (-d _) {	1175	if (-d _) {
1020	push @dirs, $entry;	1176	push @dirs, $entry;
1021		1177
1022	unless (--$ndirs) {	1178	unless (--$ndirs) {
1023	push @nondirs, @$entries;	1179	push @nondirs, @$entries;
1024	feed $statgrp;	1180	feed $statgrp;
		1181	}
		1182	} else {
		1183	push @nondirs, $entry;
1025	}	1184	}
1026	} else {
1027	push @nondirs, $entry;
1028	}	1185	}
1029	}	1186	}
1030	}	1187	};
1031	};	1188	};
1032	};	1189	};
1033	};	1190	};
1034	};	1191	};
1035	};	1192	};
1036		1193
1037	$grp	1194	$grp
1038	}	1195	}
1039		1196
1040	=item aio_rmtree $path, $callback->($status)	1197	=item aio_rmtree $pathname, $callback->($status)
1041		1198
1042	Delete a directory tree starting (and including) C<$path>, return the	1199	Delete a directory tree starting (and including) C<$path>, return the
1043	status of the final C<rmdir> only. This is a composite request that	1200	status of the final C<rmdir> only. This is a composite request that
1044	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1201	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1045	everything else.	1202	everything else.
1046		1203
1047	=cut	1204	=cut
1048		1205
…		…
1106	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1263	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1107	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1264	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1108	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1265	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1109	manpage for details.	1266	manpage for details.
1110		1267
1111	=item aio_pathsync $path, $callback->($status)	1268	=item aio_pathsync $pathname, $callback->($status)
1112		1269
1113	This request tries to open, fsync and close the given path. This is a	1270	This request tries to open, fsync and close the given path. This is a
1114	composite request intended to sync directories after directory operations	1271	composite request intended to sync directories after directory operations
1115	(E.g. rename). This might not work on all operating systems or have any	1272	(E.g. rename). This might not work on all operating systems or have any
1116	specific effect, but usually it makes sure that directory changes get	1273	specific effect, but usually it makes sure that directory changes get
…		…
1168		1325
1169	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1326	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1170	scalars.	1327	scalars.
1171		1328
1172	It touches (reads or writes) all memory pages in the specified	1329	It touches (reads or writes) all memory pages in the specified
1173	range inside the scalar. All caveats and parameters are the same	1330	range inside the scalar. All caveats and parameters are the same
1174	as for C<aio_msync>, above, except for flags, which must be either	1331	as for C<aio_msync>, above, except for flags, which must be either
1175	C<0> (which reads all pages and ensures they are instantiated) or	1332	C<0> (which reads all pages and ensures they are instantiated) or
1176	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1333	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1177	writing an octet from it, which dirties the page).	1334	writing an octet from it, which dirties the page).
1178		1335
1179	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1336	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1180		1337
1181	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1338	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1212	documented under L<MISCELLANEOUS FUNCTIONS>.	1369	documented under L<MISCELLANEOUS FUNCTIONS>.
1213		1370
1214	Example: asynchronously lock all current and future pages into memory.	1371	Example: asynchronously lock all current and future pages into memory.
1215		1372
1216	aio_mlockall IO::AIO::MCL_FUTURE;	1373	aio_mlockall IO::AIO::MCL_FUTURE;
		1374
		1375	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1376
		1377	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1378	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1379	the ioctl is not available on your OS, then this request will fail with
		1380	C<ENOSYS>.
		1381
		1382	C<$start> is the starting offset to query extents for, C<$length> is the
		1383	size of the range to query - if it is C<undef>, then the whole file will
		1384	be queried.
		1385
		1386	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1387	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1388	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1389	the data portion.
		1390
		1391	C<$count> is the maximum number of extent records to return. If it is
		1392	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1393	case, if it is C<0>, then the callback receives the number of extents
		1394	instead of the extents themselves (which is unreliable, see below).
		1395
		1396	If an error occurs, the callback receives no arguments. The special
		1397	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1398
		1399	Otherwise, the callback receives an array reference with extent
		1400	structures. Each extent structure is an array reference itself, with the
		1401	following members:
		1402
		1403	[$logical, $physical, $length, $flags]
		1404
		1405	Flags is any combination of the following flag values (typically either C<0>
		1406	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1407
		1408	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1409	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1410	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1411	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1412	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1413	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1414
		1415	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1416	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1417	it to return all extents of a range for files with large number of
		1418	extents. The code works around all these issues if C<$count> is undef.
1217		1419
1218	=item aio_group $callback->(...)	1420	=item aio_group $callback->(...)
1219		1421
1220	This is a very special aio request: Instead of doing something, it is a	1422	This is a very special aio request: Instead of doing something, it is a
1221	container for other aio requests, which is useful if you want to bundle	1423	container for other aio requests, which is useful if you want to bundle
…		…
1258	like sleep and file handle readable/writable, the overhead this creates is	1460	like sleep and file handle readable/writable, the overhead this creates is
1259	immense (it blocks a thread for a long time) so do not use this function	1461	immense (it blocks a thread for a long time) so do not use this function
1260	except to put your application under artificial I/O pressure.	1462	except to put your application under artificial I/O pressure.
1261		1463
1262	=back	1464	=back
		1465
		1466
		1467	=head2 IO::AIO::WD - multiple working directories
		1468
		1469	Your process only has one current working directory, which is used by all
		1470	threads. This makes it hard to use relative paths (some other component
		1471	could call C<chdir> at any time, and it is hard to control when the path
		1472	will be used by IO::AIO).
		1473
		1474	One solution for this is to always use absolute paths. This usually works,
		1475	but can be quite slow (the kernel has to walk the whole path on every
		1476	access), and can also be a hassle to implement.
		1477
		1478	Newer POSIX systems have a number of functions (openat, fdopendir,
		1479	futimensat and so on) that make it possible to specify working directories
		1480	per operation.
		1481
		1482	For portability, and because the clowns who "designed", or shall I write,
		1483	perpetrated this new interface were obviously half-drunk, this abstraction
		1484	cannot be perfect, though.
		1485
		1486	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1487	object. This object stores the canonicalised, absolute version of the
		1488	path, and on systems that allow it, also a directory file descriptor.
		1489
		1490	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1491	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1492	object and a pathname instead (or the IO::AIO::WD object alone, which
		1493	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1494	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1495	to that IO::AIO::WD object.
		1496
		1497	For example, to get a wd object for F</etc> and then stat F<passwd>
		1498	inside, you would write:
		1499
		1500	aio_wd "/etc", sub {
		1501	my $etcdir = shift;
		1502
		1503	# although $etcdir can be undef on error, there is generally no reason
		1504	# to check for errors here, as aio_stat will fail with ENOENT
		1505	# when $etcdir is undef.
		1506
		1507	aio_stat [$etcdir, "passwd"], sub {
		1508	# yay
		1509	};
		1510	};
		1511
		1512	The fact that C<aio_wd> is a request and not a normal function shows that
		1513	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1514	which is why it is done asynchronously.
		1515
		1516	To stat the directory obtained with C<aio_wd> above, one could write
		1517	either of the following three request calls:
		1518
		1519	aio_lstat "/etc" , sub { ... # pathname as normal string
		1520	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1521	aio_lstat $wd , sub { ... # shorthand for the previous
		1522
		1523	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1524	object and the pathname string, so you could write the following without
		1525	causing any issues due to C<$path> getting reused:
		1526
		1527	my $path = [$wd, undef];
		1528
		1529	for my $name (qw(abc def ghi)) {
		1530	$path->[1] = $name;
		1531	aio_stat $path, sub {
		1532	# ...
		1533	};
		1534	}
		1535
		1536	There are some caveats: when directories get renamed (or deleted), the
		1537	pathname string doesn't change, so will point to the new directory (or
		1538	nowhere at all), while the directory fd, if available on the system,
		1539	will still point to the original directory. Most functions accepting a
		1540	pathname will use the directory fd on newer systems, and the string on
		1541	older systems. Some functions (such as realpath) will always rely on the
		1542	string form of the pathname.
		1543
		1544	So this functionality is mainly useful to get some protection against
		1545	C<chdir>, to easily get an absolute path out of a relative path for future
		1546	reference, and to speed up doing many operations in the same directory
		1547	(e.g. when stat'ing all files in a directory).
		1548
		1549	The following functions implement this working directory abstraction:
		1550
		1551	=over 4
		1552
		1553	=item aio_wd $pathname, $callback->($wd)
		1554
		1555	Asynchonously canonicalise the given pathname and convert it to an
		1556	IO::AIO::WD object representing it. If possible and supported on the
		1557	system, also open a directory fd to speed up pathname resolution relative
		1558	to this working directory.
		1559
		1560	If something goes wrong, then C<undef> is passwd to the callback instead
		1561	of a working directory object and C<$!> is set appropriately. Since
		1562	passing C<undef> as working directory component of a pathname fails the
		1563	request with C<ENOENT>, there is often no need for error checking in the
		1564	C<aio_wd> callback, as future requests using the value will fail in the
		1565	expected way.
		1566
		1567	=item IO::AIO::CWD
		1568
		1569	This is a compiletime constant (object) that represents the process
		1570	current working directory.
		1571
		1572	Specifying this object as working directory object for a pathname is as if
		1573	the pathname would be specified directly, without a directory object. For
		1574	example, these calls are functionally identical:
		1575
		1576	aio_stat "somefile", sub { ... };
		1577	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1578
		1579	=back
		1580
		1581	To recover the path associated with an IO::AIO::WD object, you can use
		1582	C<aio_realpath>:
		1583
		1584	aio_realpath $wd, sub {
		1585	warn "path is $_[0]\n";
		1586	};
		1587
		1588	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1589	sometimes, fall back to using an absolue path.
1263		1590
1264	=head2 IO::AIO::REQ CLASS	1591	=head2 IO::AIO::REQ CLASS
1265		1592
1266	All non-aggregate C<aio_*> functions return an object of this class when	1593	All non-aggregate C<aio_*> functions return an object of this class when
1267	called in non-void context.	1594	called in non-void context.
…		…
1385		1712
1386	Sets a feeder/generator on this group: every group can have an attached	1713	Sets a feeder/generator on this group: every group can have an attached
1387	generator that generates requests if idle. The idea behind this is that,	1714	generator that generates requests if idle. The idea behind this is that,
1388	although you could just queue as many requests as you want in a group,	1715	although you could just queue as many requests as you want in a group,
1389	this might starve other requests for a potentially long time. For example,	1716	this might starve other requests for a potentially long time. For example,
1390	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1717	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1391	delaying any later requests for a long time.	1718	requests, delaying any later requests for a long time.
1392		1719
1393	To avoid this, and allow incremental generation of requests, you can	1720	To avoid this, and allow incremental generation of requests, you can
1394	instead a group and set a feeder on it that generates those requests. The	1721	instead a group and set a feeder on it that generates those requests. The
1395	feed callback will be called whenever there are few enough (see C<limit>,	1722	feed callback will be called whenever there are few enough (see C<limit>,
1396	below) requests active in the group itself and is expected to queue more	1723	below) requests active in the group itself and is expected to queue more
…		…
1445		1772
1446	See C<poll_cb> for an example.	1773	See C<poll_cb> for an example.
1447		1774
1448	=item IO::AIO::poll_cb	1775	=item IO::AIO::poll_cb
1449		1776
1450	Process some outstanding events on the result pipe. You have to call	1777	Process some requests that have reached the result phase (i.e. they have
		1778	been executed but the results are not yet reported). You have to call
		1779	this "regularly" to finish outstanding requests.
		1780
1451	this regularly. Returns C<0> if all events could be processed (or there	1781	Returns C<0> if all events could be processed (or there were no
1452	were no events to process), or C<-1> if it returned earlier for whatever	1782	events to process), or C<-1> if it returned earlier for whatever
1453	reason. Returns immediately when no events are outstanding. The amount of	1783	reason. Returns immediately when no events are outstanding. The amount
1454	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1784	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1455	C<IO::AIO::max_poll_time>.	1785	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1456		1786
1457	If not all requests were processed for whatever reason, the filehandle	1787	If not all requests were processed for whatever reason, the poll file
1458	will still be ready when C<poll_cb> returns, so normally you don't have to	1788	descriptor will still be ready when C<poll_cb> returns, so normally you
1459	do anything special to have it called later.	1789	don't have to do anything special to have it called later.
1460		1790
1461	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1791	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1462	ready, it can be beneficial to call this function from loops which submit	1792	ready, it can be beneficial to call this function from loops which submit
1463	a lot of requests, to make sure the results get processed when they become	1793	a lot of requests, to make sure the results get processed when they become
1464	available and not just when the loop is finished and the event loop takes	1794	available and not just when the loop is finished and the event loop takes
…		…
1473	poll => 'r', async => 1,	1803	poll => 'r', async => 1,
1474	cb => \&IO::AIO::poll_cb);	1804	cb => \&IO::AIO::poll_cb);
1475		1805
1476	=item IO::AIO::poll_wait	1806	=item IO::AIO::poll_wait
1477		1807
1478	If there are any outstanding requests and none of them in the result	1808	Wait until either at least one request is in the result phase or no
1479	phase, wait till the result filehandle becomes ready for reading (simply	1809	requests are outstanding anymore.
1480	does a C<select> on the filehandle. This is useful if you want to	1810
1481	synchronously wait for some requests to finish).	1811	This is useful if you want to synchronously wait for some requests to
		1812	become ready, without actually handling them.
1482		1813
1483	See C<nreqs> for an example.	1814	See C<nreqs> for an example.
1484		1815
1485	=item IO::AIO::poll	1816	=item IO::AIO::poll
1486		1817
…		…
1607		1938
1608	This is a very bad function to use in interactive programs because it	1939	This is a very bad function to use in interactive programs because it
1609	blocks, and a bad way to reduce concurrency because it is inexact: Better	1940	blocks, and a bad way to reduce concurrency because it is inexact: Better
1610	use an C<aio_group> together with a feed callback.	1941	use an C<aio_group> together with a feed callback.
1611		1942
1612	It's main use is in scripts without an event loop - when you want to stat	1943	Its main use is in scripts without an event loop - when you want to stat
1613	a lot of files, you can write somehting like this:	1944	a lot of files, you can write somehting like this:
1614		1945
1615	IO::AIO::max_outstanding 32;	1946	IO::AIO::max_outstanding 32;
1616		1947
1617	for my $path (...) {	1948	for my $path (...) {
…		…
1657		1988
1658	=back	1989	=back
1659		1990
1660	=head3 MISCELLANEOUS FUNCTIONS	1991	=head3 MISCELLANEOUS FUNCTIONS
1661		1992
1662	IO::AIO implements some functions that might be useful, but are not	1993	IO::AIO implements some functions that are useful when you want to use
1663	asynchronous.	1994	some "Advanced I/O" function not available to in Perl, without going the
		1995	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		1996	counterpart.
1664		1997
1665	=over 4	1998	=over 4
1666		1999
1667	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2000	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1668		2001
…		…
1705	ENOSYS, otherwise the return value of C<mprotect>.	2038	ENOSYS, otherwise the return value of C<mprotect>.
1706		2039
1707	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2040	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1708		2041
1709	Memory-maps a file (or anonymous memory range) and attaches it to the	2042	Memory-maps a file (or anonymous memory range) and attaches it to the
1710	given C<$scalar>, which will act like a string scalar.	2043	given C<$scalar>, which will act like a string scalar. Returns true on
		2044	success, and false otherwise.
1711		2045
1712	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2046	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1713	change the string length, and most read-only operations such as copying it	2047	change the string length, and most read-only operations such as copying it
1714	or searching it with regexes and so on.	2048	or searching it with regexes and so on.
1715		2049
…		…
1726	filesize.	2060	filesize.
1727		2061
1728	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2062	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1729	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2063	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1730		2064
1731	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2065	C<$flags> can be a combination of
1732	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2066	C<IO::AIO::MAP_SHARED> or
1733	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2067	C<IO::AIO::MAP_PRIVATE>,
		2068	or a number of system-specific flags (when not available, the are C<0>):
1734	(which is set to C<MAP_ANON> if your system only provides this	2069	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1735	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2070	C<IO::AIO::MAP_LOCKED>,
1736	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2071	C<IO::AIO::MAP_NORESERVE>,
		2072	C<IO::AIO::MAP_POPULATE>,
1737	C<IO::AIO::MAP_NONBLOCK>	2073	C<IO::AIO::MAP_NONBLOCK>,
		2074	C<IO::AIO::MAP_FIXED>,
		2075	C<IO::AIO::MAP_GROWSDOWN>,
		2076	C<IO::AIO::MAP_32BIT>,
		2077	C<IO::AIO::MAP_HUGETLB> or
		2078	C<IO::AIO::MAP_STACK>.
1738		2079
1739	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2080	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1740		2081
1741	C<$offset> is the offset from the start of the file - it generally must be	2082	C<$offset> is the offset from the start of the file - it generally must be
1742	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2083	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1767		2108
1768	Calls the C<munlockall> function.	2109	Calls the C<munlockall> function.
1769		2110
1770	On systems that do not implement C<munlockall>, this function returns	2111	On systems that do not implement C<munlockall>, this function returns
1771	ENOSYS, otherwise the return value of C<munlockall>.	2112	ENOSYS, otherwise the return value of C<munlockall>.
		2113
		2114	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2115
		2116	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2117	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2118	should be the file offset.
		2119
		2120	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2121	silently corrupt the data in this case.
		2122
		2123	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2124	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2125	C<IO::AIO::SPLICE_F_GIFT>.
		2126
		2127	See the C<splice(2)> manpage for details.
		2128
		2129	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2130
		2131	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2132	description for C<IO::AIO::splice> above for details.
		2133
		2134	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2135
		2136	Attempts to query or change the pipe buffer size. Obviously works only
		2137	on pipes, and currently works only on GNU/Linux systems, and fails with
		2138	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2139	size on other systems, drop me a note.
		2140
		2141	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2142
		2143	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2144	C<$flags> is missing or C<0>, then this should be the same as a call to
		2145	perl's built-in C<pipe> function and create a new pipe, and works on
		2146	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2147	(..., 4096, O_BINARY)>.
		2148
		2149	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2150	the given flags (Linux 2.6.27, glibc 2.9).
		2151
		2152	On success, the read and write file handles are returned.
		2153
		2154	On error, nothing will be returned. If the pipe2 syscall is missing and
		2155	C<$flags> is non-zero, fails with C<ENOSYS>.
		2156
		2157	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2158	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2159	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1772		2160
1773	=back	2161	=back
1774		2162
1775	=cut	2163	=cut
1776		2164

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing IO-AIO/AIO.pm (file contents): Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs. Revision 1.258 by root, Thu Jan 21 23:04:46 2016 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs.
Revision 1.258 by root, Thu Jan 21 23:04:46 2016 UTC