ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.181 by root, Tue May 4 21:14:01 2010 UTC vs.
Revision 1.276 by root, Fri Sep 22 05:24:41 2017 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	IO::AIO - Asynchronous Input/Output	3	IO::AIO - Asynchronous/Advanced Input/Output
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
…		…
58	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
59	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
60	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
61	using threads anyway.	61	using threads anyway.
62		62
		63	In addition to asynchronous I/O, this module also exports some rather
		64	arcane interfaces, such as C<madvise> or linux's C<splice> system call,
		65	which is why the C<A> in C<AIO> can also mean I<advanced>.
		66
63	Although the module will work in the presence of other (Perl-) threads,	67	Although the module will work in the presence of other (Perl-) threads,
64	it is currently not reentrant in any way, so use appropriate locking	68	it is currently not reentrant in any way, so use appropriate locking
65	yourself, always call C<poll_cb> from within the same thread, or never	69	yourself, always call C<poll_cb> from within the same thread, or never
66	call C<poll_cb> (or other C<aio_> functions) recursively.	70	call C<poll_cb> (or other C<aio_> functions) recursively.
67		71
68	=head2 EXAMPLE	72	=head2 EXAMPLE
69		73
70	This is a simple example that uses the EV module and loads	74	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	75	F</etc/passwd> asynchronously:
72		76
73	use Fcntl;
74	use EV;	77	use EV;
75	use IO::AIO;	78	use IO::AIO;
76		79
77	# register the IO::AIO callback with EV	80	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	81	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		98
96	# file contents now in $contents	99	# file contents now in $contents
97	print $contents;	100	print $contents;
98		101
99	# exit event loop and program	102	# exit event loop and program
100	EV::unloop;	103	EV::break;
101	};	104	};
102	};	105	};
103		106
104	# possibly queue up other requests, or open GUI windows,	107	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	108	# check for sockets etc. etc.
106		109
107	# process events as long as there are some:	110	# process events as long as there are some:
108	EV::loop;	111	EV::run;
109		112
110	=head1 REQUEST ANATOMY AND LIFETIME	113	=head1 REQUEST ANATOMY AND LIFETIME
111		114
112	Every C<aio_*> function creates a request. which is a C data structure not	115	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	116	directly visible to Perl.
…		…
168	use common::sense;	171	use common::sense;
169		172
170	use base 'Exporter';	173	use base 'Exporter';
171		174
172	BEGIN {	175	BEGIN {
173	our $VERSION = '3.65';	176	our $VERSION = 4.35;
174		177
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	178	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	179	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
		182	aio_pathsync aio_readahead aio_fiemap aio_allocate
179	aio_rename aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_statvfs);	186	aio_msync aio_mtouch aio_mlock aio_mlockall
		187	aio_statvfs
		188	aio_wd);
183		189
184	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	190	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
185	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	191	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
186	min_parallel max_parallel max_idle	192	min_parallel max_parallel max_idle idle_timeout
187	nreqs nready npending nthreads	193	nreqs nready npending nthreads
188	max_poll_time max_poll_reqs	194	max_poll_time max_poll_reqs
189	sendfile fadvise);	195	sendfile fadvise madvise
		196	mmap munmap munlock munlockall);
190		197
191	push @AIO_REQ, qw(aio_busy); # not exported	198	push @AIO_REQ, qw(aio_busy); # not exported
192		199
193	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	200	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
194		201
…		…
198		205
199	=head1 FUNCTIONS	206	=head1 FUNCTIONS
200		207
201	=head2 QUICK OVERVIEW	208	=head2 QUICK OVERVIEW
202		209
203	This section simply lists the prototypes of the most important functions	210	This section simply lists the prototypes most of the functions for
204	for quick reference. See the following sections for function-by-function	211	quick reference. See the following sections for function-by-function
205	documentation.	212	documentation.
206		213
		214	aio_wd $pathname, $callback->($wd)
207	aio_open $pathname, $flags, $mode, $callback->($fh)	215	aio_open $pathname, $flags, $mode, $callback->($fh)
208	aio_close $fh, $callback->($status)	216	aio_close $fh, $callback->($status)
		217	aio_seek $fh,$offset,$whence, $callback->($offs)
209	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	218	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
210	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	219	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
211	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	220	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
212	aio_readahead $fh,$offset,$length, $callback->($retval)	221	aio_readahead $fh,$offset,$length, $callback->($retval)
213	aio_stat $fh_or_path, $callback->($status)	222	aio_stat $fh_or_path, $callback->($status)
214	aio_lstat $fh, $callback->($status)	223	aio_lstat $fh, $callback->($status)
215	aio_statvfs $fh_or_path, $callback->($statvfs)	224	aio_statvfs $fh_or_path, $callback->($statvfs)
216	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	225	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
217	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	226	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		227	aio_chmod $fh_or_path, $mode, $callback->($status)
218	aio_truncate $fh_or_path, $offset, $callback->($status)	228	aio_truncate $fh_or_path, $offset, $callback->($status)
219	aio_chmod $fh_or_path, $mode, $callback->($status)	229	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		230	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
220	aio_unlink $pathname, $callback->($status)	231	aio_unlink $pathname, $callback->($status)
221	aio_mknod $path, $mode, $dev, $callback->($status)	232	aio_mknod $pathname, $mode, $dev, $callback->($status)
222	aio_link $srcpath, $dstpath, $callback->($status)	233	aio_link $srcpath, $dstpath, $callback->($status)
223	aio_symlink $srcpath, $dstpath, $callback->($status)	234	aio_symlink $srcpath, $dstpath, $callback->($status)
224	aio_readlink $path, $callback->($link)	235	aio_readlink $pathname, $callback->($link)
		236	aio_realpath $pathname, $callback->($path)
225	aio_rename $srcpath, $dstpath, $callback->($status)	237	aio_rename $srcpath, $dstpath, $callback->($status)
		238	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
226	aio_mkdir $pathname, $mode, $callback->($status)	239	aio_mkdir $pathname, $mode, $callback->($status)
227	aio_rmdir $pathname, $callback->($status)	240	aio_rmdir $pathname, $callback->($status)
228	aio_readdir $pathname, $callback->($entries)	241	aio_readdir $pathname, $callback->($entries)
229	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	242	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
230	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	243	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
231	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	244	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		245	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
232	aio_load $path, $data, $callback->($status)	246	aio_load $pathname, $data, $callback->($status)
233	aio_copy $srcpath, $dstpath, $callback->($status)	247	aio_copy $srcpath, $dstpath, $callback->($status)
234	aio_move $srcpath, $dstpath, $callback->($status)	248	aio_move $srcpath, $dstpath, $callback->($status)
235	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
236	aio_rmtree $path, $callback->($status)	249	aio_rmtree $pathname, $callback->($status)
		250	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		251	aio_ioctl $fh, $request, $buf, $callback->($status)
237	aio_sync $callback->($status)	252	aio_sync $callback->($status)
		253	aio_syncfs $fh, $callback->($status)
238	aio_fsync $fh, $callback->($status)	254	aio_fsync $fh, $callback->($status)
239	aio_fdatasync $fh, $callback->($status)	255	aio_fdatasync $fh, $callback->($status)
240	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	256	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
241	aio_pathsync $path, $callback->($status)	257	aio_pathsync $pathname, $callback->($status)
242	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	258	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
243	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		260	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		261	aio_mlockall $flags, $callback->($status)
244	aio_group $callback->(...)	262	aio_group $callback->(...)
245	aio_nop $callback->()	263	aio_nop $callback->()
246		264
247	$prev_pri = aioreq_pri [$pri]	265	$prev_pri = aioreq_pri [$pri]
248	aioreq_nice $pri_adjust	266	aioreq_nice $pri_adjust
…		…
254	IO::AIO::max_poll_reqs $nreqs	272	IO::AIO::max_poll_reqs $nreqs
255	IO::AIO::max_poll_time $seconds	273	IO::AIO::max_poll_time $seconds
256	IO::AIO::min_parallel $nthreads	274	IO::AIO::min_parallel $nthreads
257	IO::AIO::max_parallel $nthreads	275	IO::AIO::max_parallel $nthreads
258	IO::AIO::max_idle $nthreads	276	IO::AIO::max_idle $nthreads
		277	IO::AIO::idle_timeout $seconds
259	IO::AIO::max_outstanding $maxreqs	278	IO::AIO::max_outstanding $maxreqs
260	IO::AIO::nreqs	279	IO::AIO::nreqs
261	IO::AIO::nready	280	IO::AIO::nready
262	IO::AIO::npending	281	IO::AIO::npending
		282	IO::AIO::min_fdlimit $nfd;
263		283
264	IO::AIO::sendfile $ofh, $ifh, $offset, $count	284	IO::AIO::sendfile $ofh, $ifh, $offset, $count
265	IO::AIO::fadvise $fh, $offset, $len, $advice	285	IO::AIO::fadvise $fh, $offset, $len, $advice
266	IO::AIO::mlockall $flags	286	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		287	IO::AIO::munmap $scalar
		288	IO::AIO::madvise $scalar, $offset, $length, $advice
		289	IO::AIO::mprotect $scalar, $offset, $length, $protect
		290	IO::AIO::munlock $scalar, $offset = 0, $length = undef
267	IO::AIO::munlockall	291	IO::AIO::munlockall
268		292
269	=head2 AIO REQUEST FUNCTIONS	293	=head2 API NOTES
270		294
271	All the C<aio_*> calls are more or less thin wrappers around the syscall	295	All the C<aio_*> calls are more or less thin wrappers around the syscall
272	with the same name (sans C<aio_>). The arguments are similar or identical,	296	with the same name (sans C<aio_>). The arguments are similar or identical,
273	and they all accept an additional (and optional) C<$callback> argument	297	and they all accept an additional (and optional) C<$callback> argument
274	which must be a code reference. This code reference will get called with	298	which must be a code reference. This code reference will be called after
275	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	299	the syscall has been executed in an asynchronous fashion. The results
276	perl, which usually delivers "false") as its sole argument after the given	300	of the request will be passed as arguments to the callback (and, if an
277	syscall has been executed asynchronously.	301	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		302	most syscalls return C<-1> on error, unlike perl, which usually delivers
		303	"false").
		304
		305	Some requests (such as C<aio_readdir>) pass the actual results and
		306	communicate failures by passing C<undef>.
278		307
279	All functions expecting a filehandle keep a copy of the filehandle	308	All functions expecting a filehandle keep a copy of the filehandle
280	internally until the request has finished.	309	internally until the request has finished.
281		310
282	All functions return request objects of type L<IO::AIO::REQ> that allow	311	All functions return request objects of type L<IO::AIO::REQ> that allow
283	further manipulation of those requests while they are in-flight.	312	further manipulation of those requests while they are in-flight.
284		313
285	The pathnames you pass to these routines I<must> be absolute and	314	The pathnames you pass to these routines I<should> be absolute. The
286	encoded as octets. The reason for the former is that at the time the	315	reason for this is that at the time the request is being executed, the
287	request is being executed, the current working directory could have	316	current working directory could have changed. Alternatively, you can
288	changed. Alternatively, you can make sure that you never change the	317	make sure that you never change the current working directory anywhere
289	current working directory anywhere in the program and then use relative	318	in the program and then use relative paths. You can also take advantage
290	paths.	319	of IO::AIOs working directory abstraction, that lets you specify paths
		320	relative to some previously-opened "working directory object" - see the
		321	description of the C<IO::AIO::WD> class later in this document.
291		322
292	To encode pathnames as octets, either make sure you either: a) always pass	323	To encode pathnames as octets, either make sure you either: a) always pass
293	in filenames you got from outside (command line, readdir etc.) without	324	in filenames you got from outside (command line, readdir etc.) without
294	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	325	tinkering, b) are in your native filesystem encoding, c) use the Encode
295	your pathnames to the locale (or other) encoding in effect in the user	326	module and encode your pathnames to the locale (or other) encoding in
296	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	327	effect in the user environment, d) use Glib::filename_from_unicode on
297	use something else to ensure your scalar has the correct contents.	328	unicode filenames or e) use something else to ensure your scalar has the
		329	correct contents.
298		330
299	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	331	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
300	handles correctly whether it is set or not.	332	handles correctly whether it is set or not.
		333
		334	=head2 AIO REQUEST FUNCTIONS
301		335
302	=over 4	336	=over 4
303		337
304	=item $prev_pri = aioreq_pri [$pri]	338	=item $prev_pri = aioreq_pri [$pri]
305		339
…		…
335		369
336		370
337	=item aio_open $pathname, $flags, $mode, $callback->($fh)	371	=item aio_open $pathname, $flags, $mode, $callback->($fh)
338		372
339	Asynchronously open or create a file and call the callback with a newly	373	Asynchronously open or create a file and call the callback with a newly
340	created filehandle for the file.	374	created filehandle for the file (or C<undef> in case of an error).
341		375
342	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	376	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
343	for an explanation.	377	for an explanation.
344		378
345	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	379	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
361	} else {	395	} else {
362	die "open failed: $!\n";	396	die "open failed: $!\n";
363	}	397	}
364	};	398	};
365		399
		400	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		401	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		402	following POSIX and non-POSIX constants are available (missing ones on
		403	your system are, as usual, C<0>):
		404
		405	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		406	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		407	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
		408
366		409
367	=item aio_close $fh, $callback->($status)	410	=item aio_close $fh, $callback->($status)
368		411
369	Asynchronously close a file and call the callback with the result	412	Asynchronously close a file and call the callback with the result
370	code.	413	code.
…		…
379	Or in other words: the file descriptor will be closed, but it will not be	422	Or in other words: the file descriptor will be closed, but it will not be
380	free for reuse until the perl filehandle is closed.	423	free for reuse until the perl filehandle is closed.
381		424
382	=cut	425	=cut
383		426
		427	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		428
		429	Seeks the filehandle to the new C<$offset>, similarly to perl's
		430	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		431	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		432	C<IO::AIO::SEEK_END>).
		433
		434	The resulting absolute offset will be passed to the callback, or C<-1> in
		435	case of an error.
		436
		437	In theory, the C<$whence> constants could be different than the
		438	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		439	so don't panic.
		440
		441	As a GNU/Linux (and maybe Solaris) extension, also the constants
		442	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		443	could be found. No guarantees about suitability for use in C<aio_seek> or
		444	Perl's C<sysseek> can be made though, although I would naively assume they
		445	"just work".
		446
384	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	447	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
385		448
386	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	449	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
387		450
388	Reads or writes C<$length> bytes from or to the specified C<$fh> and	451	Reads or writes C<$length> bytes from or to the specified C<$fh> and
389	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	452	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
390	and calls the callback without the actual number of bytes read (or -1 on	453	calls the callback with the actual number of bytes transferred (or -1 on
391	error, just like the syscall).	454	error, just like the syscall).
392		455
393	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	456	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
394	offset plus the actual number of bytes read.	457	offset plus the actual number of bytes read.
395		458
…		…
420		483
421	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	484	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
422	reading at byte offset C<$in_offset>, and starts writing at the current	485	reading at byte offset C<$in_offset>, and starts writing at the current
423	file offset of C<$out_fh>. Because of that, it is not safe to issue more	486	file offset of C<$out_fh>. Because of that, it is not safe to issue more
424	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	487	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
425	other.	488	other. The same C<$in_fh> works fine though, as this function does not
		489	move or use the file offset of C<$in_fh>.
426		490
		491	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		492	are written, and there is no way to find out how many more bytes have been
		493	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		494	number of bytes written to C<$out_fh>. Only if the result value equals
		495	C<$length> one can assume that C<$length> bytes have been read.
		496
		497	Unlike with other C<aio_> functions, it makes a lot of sense to use
		498	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		499	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		500	the socket I/O will be non-blocking. Note, however, that you can run
		501	into a trap where C<aio_sendfile> reads some data with readahead, then
		502	fails to write all data, and when the socket is ready the next time, the
		503	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		504	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		505	resource usage.
		506
427	This call tries to make use of a native C<sendfile> syscall to provide	507	This call tries to make use of a native C<sendfile>-like syscall to
428	zero-copy operation. For this to work, C<$out_fh> should refer to a	508	provide zero-copy operation. For this to work, C<$out_fh> should refer to
429	socket, and C<$in_fh> should refer to an mmap'able file.	509	a socket, and C<$in_fh> should refer to an mmap'able file.
430		510
431	If a native sendfile cannot be found or it fails with C<ENOSYS>,	511	If a native sendfile cannot be found or it fails with C<ENOSYS>,
432	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	512	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
433	it will be emulated, so you can call C<aio_sendfile> on any type of	513	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
434	filehandle regardless of the limitations of the operating system.	514	type of filehandle regardless of the limitations of the operating system.
435		515
436	Please note, however, that C<aio_sendfile> can read more bytes from	516	As native sendfile syscalls (as practically any non-POSIX interface hacked
437	C<$in_fh> than are written, and there is no way to find out how many	517	together in a hurry to improve benchmark numbers) tend to be rather buggy
438	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	518	on many systems, this implementation tries to work around some known bugs
439	provides the number of bytes written to C<$out_fh>. Only if the result	519	in Linux and FreeBSD kernels (probably others, too), but that might fail,
440	value equals C<$length> one can assume that C<$length> bytes have been	520	so you really really should check the return value of C<aio_sendfile> -
441	read.	521	fewer bytes than expected might have been transferred.
442		522
443		523
444	=item aio_readahead $fh,$offset,$length, $callback->($retval)	524	=item aio_readahead $fh,$offset,$length, $callback->($retval)
445		525
446	C<aio_readahead> populates the page cache with data from a file so that	526	C<aio_readahead> populates the page cache with data from a file so that
…		…
450	whole pages, so that offset is effectively rounded down to a page boundary	530	whole pages, so that offset is effectively rounded down to a page boundary
451	and bytes are read up to the next page boundary greater than or equal to	531	and bytes are read up to the next page boundary greater than or equal to
452	(off-set+length). C<aio_readahead> does not read beyond the end of the	532	(off-set+length). C<aio_readahead> does not read beyond the end of the
453	file. The current file offset of the file is left unchanged.	533	file. The current file offset of the file is left unchanged.
454		534
455	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	535	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
456	emulated by simply reading the data, which would have a similar effect.	536	be emulated by simply reading the data, which would have a similar effect.
457		537
458		538
459	=item aio_stat $fh_or_path, $callback->($status)	539	=item aio_stat $fh_or_path, $callback->($status)
460		540
461	=item aio_lstat $fh, $callback->($status)	541	=item aio_lstat $fh, $callback->($status)
…		…
468	for an explanation.	548	for an explanation.
469		549
470	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	550	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
471	error when stat'ing a large file, the results will be silently truncated	551	error when stat'ing a large file, the results will be silently truncated
472	unless perl itself is compiled with large file support.	552	unless perl itself is compiled with large file support.
		553
		554	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		555	following constants and functions (if not implemented, the constants will
		556	be C<0> and the functions will either C<croak> or fall back on traditional
		557	behaviour).
		558
		559	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		560	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		561	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
473		562
474	Example: Print the length of F</etc/passwd>:	563	Example: Print the length of F</etc/passwd>:
475		564
476	aio_stat "/etc/passwd", sub {	565	aio_stat "/etc/passwd", sub {
477	$_[0] and die "stat failed: $!";	566	$_[0] and die "stat failed: $!";
…		…
521	namemax => 255,	610	namemax => 255,
522	frsize => 1024,	611	frsize => 1024,
523	fsid => 1810	612	fsid => 1810
524	}	613	}
525		614
		615	Here is a (likely partial - send me updates!) list of fsid values used by
		616	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		617
		618	0x0000adf5 adfs
		619	0x0000adff affs
		620	0x5346414f afs
		621	0x09041934 anon-inode filesystem
		622	0x00000187 autofs
		623	0x42465331 befs
		624	0x1badface bfs
		625	0x42494e4d binfmt_misc
		626	0x9123683e btrfs
		627	0x0027e0eb cgroupfs
		628	0xff534d42 cifs
		629	0x73757245 coda
		630	0x012ff7b7 coh
		631	0x28cd3d45 cramfs
		632	0x453dcd28 cramfs-wend (wrong endianness)
		633	0x64626720 debugfs
		634	0x00001373 devfs
		635	0x00001cd1 devpts
		636	0x0000f15f ecryptfs
		637	0x00414a53 efs
		638	0x0000137d ext
		639	0x0000ef53 ext2/ext3/ext4
		640	0x0000ef51 ext2
		641	0xf2f52010 f2fs
		642	0x00004006 fat
		643	0x65735546 fuseblk
		644	0x65735543 fusectl
		645	0x0bad1dea futexfs
		646	0x01161970 gfs2
		647	0x47504653 gpfs
		648	0x00004244 hfs
		649	0xf995e849 hpfs
		650	0x00c0ffee hostfs
		651	0x958458f6 hugetlbfs
		652	0x2bad1dea inotifyfs
		653	0x00009660 isofs
		654	0x000072b6 jffs2
		655	0x3153464a jfs
		656	0x6b414653 k-afs
		657	0x0bd00bd0 lustre
		658	0x0000137f minix
		659	0x0000138f minix 30 char names
		660	0x00002468 minix v2
		661	0x00002478 minix v2 30 char names
		662	0x00004d5a minix v3
		663	0x19800202 mqueue
		664	0x00004d44 msdos
		665	0x0000564c novell
		666	0x00006969 nfs
		667	0x6e667364 nfsd
		668	0x00003434 nilfs
		669	0x5346544e ntfs
		670	0x00009fa1 openprom
		671	0x7461636F ocfs2
		672	0x00009fa0 proc
		673	0x6165676c pstorefs
		674	0x0000002f qnx4
		675	0x68191122 qnx6
		676	0x858458f6 ramfs
		677	0x52654973 reiserfs
		678	0x00007275 romfs
		679	0x67596969 rpc_pipefs
		680	0x73636673 securityfs
		681	0xf97cff8c selinux
		682	0x0000517b smb
		683	0x534f434b sockfs
		684	0x73717368 squashfs
		685	0x62656572 sysfs
		686	0x012ff7b6 sysv2
		687	0x012ff7b5 sysv4
		688	0x01021994 tmpfs
		689	0x15013346 udf
		690	0x00011954 ufs
		691	0x54190100 ufs byteswapped
		692	0x00009fa2 usbdevfs
		693	0x01021997 v9fs
		694	0xa501fcf5 vxfs
		695	0xabba1974 xenfs
		696	0x012ff7b4 xenix
		697	0x58465342 xfs
		698	0x012fd16d xia
526		699
527	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	700	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
528		701
529	Works like perl's C<utime> function (including the special case of $atime	702	Works like perl's C<utime> function (including the special case of $atime
530	and $mtime being undef). Fractional times are supported if the underlying	703	and $mtime being undef). Fractional times are supported if the underlying
…		…
558	=item aio_truncate $fh_or_path, $offset, $callback->($status)	731	=item aio_truncate $fh_or_path, $offset, $callback->($status)
559		732
560	Works like truncate(2) or ftruncate(2).	733	Works like truncate(2) or ftruncate(2).
561		734
562		735
		736	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		737
		738	Allocates or frees disk space according to the C<$mode> argument. See the
		739	linux C<fallocate> documentation for details.
		740
		741	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		742	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
		743	to deallocate a file range.
		744
		745	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		746	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		747	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		748	to unshare shared blocks (see your L<fallocate(2)> manpage).
		749
		750	The file system block size used by C<fallocate> is presumably the
		751	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		752	can dictate other limitations.
		753
		754	If C<fallocate> isn't available or cannot be emulated (currently no
		755	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		756
		757
563	=item aio_chmod $fh_or_path, $mode, $callback->($status)	758	=item aio_chmod $fh_or_path, $mode, $callback->($status)
564		759
565	Works like perl's C<chmod> function.	760	Works like perl's C<chmod> function.
566		761
567		762
…		…
569		764
570	Asynchronously unlink (delete) a file and call the callback with the	765	Asynchronously unlink (delete) a file and call the callback with the
571	result code.	766	result code.
572		767
573		768
574	=item aio_mknod $path, $mode, $dev, $callback->($status)	769	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
575		770
576	[EXPERIMENTAL]	771	[EXPERIMENTAL]
577		772
578	Asynchronously create a device node (or fifo). See mknod(2).	773	Asynchronously create a device node (or fifo). See mknod(2).
579		774
580	The only (POSIX-) portable way of calling this function is:	775	The only (POSIX-) portable way of calling this function is:
581		776
582	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	777	aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
583		778
		779	See C<aio_stat> for info about some potentially helpful extra constants
		780	and functions.
584		781
585	=item aio_link $srcpath, $dstpath, $callback->($status)	782	=item aio_link $srcpath, $dstpath, $callback->($status)
586		783
587	Asynchronously create a new link to the existing object at C<$srcpath> at	784	Asynchronously create a new link to the existing object at C<$srcpath> at
588	the path C<$dstpath> and call the callback with the result code.	785	the path C<$dstpath> and call the callback with the result code.
…		…
592		789
593	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	790	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
594	the path C<$dstpath> and call the callback with the result code.	791	the path C<$dstpath> and call the callback with the result code.
595		792
596		793
597	=item aio_readlink $path, $callback->($link)	794	=item aio_readlink $pathname, $callback->($link)
598		795
599	Asynchronously read the symlink specified by C<$path> and pass it to	796	Asynchronously read the symlink specified by C<$path> and pass it to
600	the callback. If an error occurs, nothing or undef gets passed to the	797	the callback. If an error occurs, nothing or undef gets passed to the
601	callback.	798	callback.
602		799
603		800
		801	=item aio_realpath $pathname, $callback->($path)
		802
		803	Asynchronously make the path absolute and resolve any symlinks in
		804	C<$path>. The resulting path only consists of directories (same as
		805	L<Cwd::realpath>).
		806
		807	This request can be used to get the absolute path of the current working
		808	directory by passing it a path of F<.> (a single dot).
		809
		810
604	=item aio_rename $srcpath, $dstpath, $callback->($status)	811	=item aio_rename $srcpath, $dstpath, $callback->($status)
605		812
606	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	813	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
607	rename(2) and call the callback with the result code.	814	rename(2) and call the callback with the result code.
		815
		816	On systems that support the AIO::WD working directory abstraction
		817	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		818	of failing, C<rename> is called on the absolute path of C<$wd>.
		819
		820
		821	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		822
		823	Basically a version of C<aio_rename> with an additional C<$flags>
		824	argument. Calling this with C<$flags=0> is the same as calling
		825	C<aio_rename>.
		826
		827	Non-zero flags are currently only supported on GNU/Linux systems that
		828	support renameat2. Other systems fail with C<ENOSYS> in this case.
		829
		830	The following constants are available (missing ones are, as usual C<0>),
		831	see renameat2(2) for details:
		832
		833	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		834	and C<IO::AIO::RENAME_WHITEOUT>.
608		835
609		836
610	=item aio_mkdir $pathname, $mode, $callback->($status)	837	=item aio_mkdir $pathname, $mode, $callback->($status)
611		838
612	Asynchronously mkdir (create) a directory and call the callback with	839	Asynchronously mkdir (create) a directory and call the callback with
…		…
617	=item aio_rmdir $pathname, $callback->($status)	844	=item aio_rmdir $pathname, $callback->($status)
618		845
619	Asynchronously rmdir (delete) a directory and call the callback with the	846	Asynchronously rmdir (delete) a directory and call the callback with the
620	result code.	847	result code.
621		848
		849	On systems that support the AIO::WD working directory abstraction
		850	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		851	C<rmdir> is called on the absolute path of C<$wd>.
		852
622		853
623	=item aio_readdir $pathname, $callback->($entries)	854	=item aio_readdir $pathname, $callback->($entries)
624		855
625	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	856	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
626	directory (i.e. opendir + readdir + closedir). The entries will not be	857	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
630	array-ref with the filenames.	861	array-ref with the filenames.
631		862
632		863
633	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	864	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
634		865
635	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	866	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
636	behaviour and output format. In case of an error, C<$entries> will be	867	tune behaviour and output format. In case of an error, C<$entries> will be
637	C<undef>.	868	C<undef>.
638		869
639	The flags are a combination of the following constants, ORed together (the	870	The flags are a combination of the following constants, ORed together (the
640	flags will also be passed to the callback, possibly modified):	871	flags will also be passed to the callback, possibly modified):
641		872
642	=over 4	873	=over 4
643		874
644	=item IO::AIO::READDIR_DENTS	875	=item IO::AIO::READDIR_DENTS
645		876
646	When this flag is off, then the callback gets an arrayref with of names	877	When this flag is off, then the callback gets an arrayref consisting of
647	only (as with C<aio_readdir>), otherwise it gets an arrayref with	878	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
648	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	879	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
649	entry in more detail.	880	entry in more detail.
650		881
651	C<$name> is the name of the entry.	882	C<$name> is the name of the entry.
652		883
…		…
665	systems that do not deliver the inode information.	896	systems that do not deliver the inode information.
666		897
667	=item IO::AIO::READDIR_DIRS_FIRST	898	=item IO::AIO::READDIR_DIRS_FIRST
668		899
669	When this flag is set, then the names will be returned in an order where	900	When this flag is set, then the names will be returned in an order where
670	likely directories come first. This is useful when you need to quickly	901	likely directories come first, in optimal stat order. This is useful when
671	find directories, or you want to find all directories while avoiding to	902	you need to quickly find directories, or you want to find all directories
672	stat() each entry.	903	while avoiding to stat() each entry.
673		904
674	If the system returns type information in readdir, then this is used	905	If the system returns type information in readdir, then this is used
675	to find directories directly. Otherwise, likely directories are files	906	to find directories directly. Otherwise, likely directories are names
676	beginning with ".", or otherwise files with no dots, of which files with	907	beginning with ".", or otherwise names with no dots, of which names with
677	short names are tried first.	908	short names are tried first.
678		909
679	=item IO::AIO::READDIR_STAT_ORDER	910	=item IO::AIO::READDIR_STAT_ORDER
680		911
681	When this flag is set, then the names will be returned in an order	912	When this flag is set, then the names will be returned in an order
…		…
688		919
689	=item IO::AIO::READDIR_FOUND_UNKNOWN	920	=item IO::AIO::READDIR_FOUND_UNKNOWN
690		921
691	This flag should not be set when calling C<aio_readdirx>. Instead, it	922	This flag should not be set when calling C<aio_readdirx>. Instead, it
692	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	923	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
693	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	924	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
694	C<$type>'s are known, which can be used to speed up some algorithms.	925	C<$type>'s are known, which can be used to speed up some algorithms.
695		926
696	=back	927	=back
697		928
698		929
699	=item aio_load $path, $data, $callback->($status)	930	=item aio_load $pathname, $data, $callback->($status)
700		931
701	This is a composite request that tries to fully load the given file into	932	This is a composite request that tries to fully load the given file into
702	memory. Status is the same as with aio_read.	933	memory. Status is the same as with aio_read.
703		934
704	=cut	935	=cut
…		…
727	=item aio_copy $srcpath, $dstpath, $callback->($status)	958	=item aio_copy $srcpath, $dstpath, $callback->($status)
728		959
729	Try to copy the I<file> (directories not supported as either source or	960	Try to copy the I<file> (directories not supported as either source or
730	destination) from C<$srcpath> to C<$dstpath> and call the callback with	961	destination) from C<$srcpath> to C<$dstpath> and call the callback with
731	a status of C<0> (ok) or C<-1> (error, see C<$!>).	962	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		963
		964	Existing destination files will be truncated.
732		965
733	This is a composite request that creates the destination file with	966	This is a composite request that creates the destination file with
734	mode 0200 and copies the contents of the source file into it using	967	mode 0200 and copies the contents of the source file into it using
735	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	968	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
736	uid/gid, in that order.	969	uid/gid, in that order.
…		…
826	if ($_[0] && $! == EXDEV) {	1059	if ($_[0] && $! == EXDEV) {
827	aioreq_pri $pri;	1060	aioreq_pri $pri;
828	add $grp aio_copy $src, $dst, sub {	1061	add $grp aio_copy $src, $dst, sub {
829	$grp->result ($_[0]);	1062	$grp->result ($_[0]);
830		1063
831	if (!$_[0]) {	1064	unless ($_[0]) {
832	aioreq_pri $pri;	1065	aioreq_pri $pri;
833	add $grp aio_unlink $src;	1066	add $grp aio_unlink $src;
834	}	1067	}
835	};	1068	};
836	} else {	1069	} else {
…		…
839	};	1072	};
840		1073
841	$grp	1074	$grp
842	}	1075	}
843		1076
844	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1077	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
845		1078
846	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1079	Scans a directory (similar to C<aio_readdir>) but additionally tries to
847	efficiently separate the entries of directory C<$path> into two sets of	1080	efficiently separate the entries of directory C<$path> into two sets of
848	names, directories you can recurse into (directories), and ones you cannot	1081	names, directories you can recurse into (directories), and ones you cannot
849	recurse into (everything else, including symlinks to directories).	1082	recurse into (everything else, including symlinks to directories).
…		…
880	Then entries will be sorted into likely directories a non-initial dot	1113	Then entries will be sorted into likely directories a non-initial dot
881	currently) and likely non-directories (see C<aio_readdirx>). Then every	1114	currently) and likely non-directories (see C<aio_readdirx>). Then every
882	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1115	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
883	in order of their inode numbers. If that succeeds, it assumes that the	1116	in order of their inode numbers. If that succeeds, it assumes that the
884	entry is a directory or a symlink to directory (which will be checked	1117	entry is a directory or a symlink to directory (which will be checked
885	seperately). This is often faster than stat'ing the entry itself because	1118	separately). This is often faster than stat'ing the entry itself because
886	filesystems might detect the type of the entry without reading the inode	1119	filesystems might detect the type of the entry without reading the inode
887	data (e.g. ext2fs filetype feature), even on systems that cannot return	1120	data (e.g. ext2fs filetype feature), even on systems that cannot return
888	the filetype information on readdir.	1121	the filetype information on readdir.
889		1122
890	If the known number of directories (link count - 2) has been reached, the	1123	If the known number of directories (link count - 2) has been reached, the
…		…
906		1139
907	my $grp = aio_group $cb;	1140	my $grp = aio_group $cb;
908		1141
909	$maxreq = 4 if $maxreq <= 0;	1142	$maxreq = 4 if $maxreq <= 0;
910		1143
911	# stat once	1144	# get a wd object
912	aioreq_pri $pri;	1145	aioreq_pri $pri;
913	add $grp aio_stat $path, sub {	1146	add $grp aio_wd $path, sub {
		1147	$_[0]
914	return $grp->result () if $_[0];	1148	or return $grp->result ();
915	my $now = time;
916	my $hash1 = join ":", (stat _)[0,1,3,7,9];
917		1149
918	# read the directory entries	1150	my $wd = [shift, "."];
		1151
		1152	# stat once
919	aioreq_pri $pri;	1153	aioreq_pri $pri;
920	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1154	add $grp aio_stat $wd, sub {
921	my $entries = shift
922	or return $grp->result ();	1155	return $grp->result () if $_[0];
		1156	my $now = time;
		1157	my $hash1 = join ":", (stat _)[0,1,3,7,9];
923		1158
924	# stat the dir another time	1159	# read the directory entries
925	aioreq_pri $pri;	1160	aioreq_pri $pri;
		1161	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1162	my $entries = shift
		1163	or return $grp->result ();
		1164
		1165	# stat the dir another time
		1166	aioreq_pri $pri;
926	add $grp aio_stat $path, sub {	1167	add $grp aio_stat $wd, sub {
927	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1168	my $hash2 = join ":", (stat _)[0,1,3,7,9];
928		1169
929	my $ndirs;	1170	my $ndirs;
930		1171
931	# take the slow route if anything looks fishy	1172	# take the slow route if anything looks fishy
932	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1173	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
933	$ndirs = -1;	1174	$ndirs = -1;
934	} else {	1175	} else {
935	# if nlink == 2, we are finished	1176	# if nlink == 2, we are finished
936	# for non-posix-fs's, we rely on nlink < 2	1177	# for non-posix-fs's, we rely on nlink < 2
937	$ndirs = (stat _)[3] - 2	1178	$ndirs = (stat _)[3] - 2
938	or return $grp->result ([], $entries);	1179	or return $grp->result ([], $entries);
939	}	1180	}
940		1181
941	my (@dirs, @nondirs);	1182	my (@dirs, @nondirs);
942		1183
943	my $statgrp = add $grp aio_group sub {	1184	my $statgrp = add $grp aio_group sub {
944	$grp->result (\@dirs, \@nondirs);	1185	$grp->result (\@dirs, \@nondirs);
945	};	1186	};
946		1187
947	limit $statgrp $maxreq;	1188	limit $statgrp $maxreq;
948	feed $statgrp sub {	1189	feed $statgrp sub {
949	return unless @$entries;	1190	return unless @$entries;
950	my $entry = shift @$entries;	1191	my $entry = shift @$entries;
951		1192
952	aioreq_pri $pri;	1193	aioreq_pri $pri;
		1194	$wd->[1] = "$entry/.";
953	add $statgrp aio_stat "$path/$entry/.", sub {	1195	add $statgrp aio_stat $wd, sub {
954	if ($_[0] < 0) {	1196	if ($_[0] < 0) {
955	push @nondirs, $entry;	1197	push @nondirs, $entry;
956	} else {	1198	} else {
957	# need to check for real directory	1199	# need to check for real directory
958	aioreq_pri $pri;	1200	aioreq_pri $pri;
		1201	$wd->[1] = $entry;
959	add $statgrp aio_lstat "$path/$entry", sub {	1202	add $statgrp aio_lstat $wd, sub {
960	if (-d _) {	1203	if (-d _) {
961	push @dirs, $entry;	1204	push @dirs, $entry;
962		1205
963	unless (--$ndirs) {	1206	unless (--$ndirs) {
964	push @nondirs, @$entries;	1207	push @nondirs, @$entries;
965	feed $statgrp;	1208	feed $statgrp;
		1209	}
		1210	} else {
		1211	push @nondirs, $entry;
966	}	1212	}
967	} else {
968	push @nondirs, $entry;
969	}	1213	}
970	}	1214	}
971	}	1215	};
972	};	1216	};
973	};	1217	};
974	};	1218	};
975	};	1219	};
976	};	1220	};
977		1221
978	$grp	1222	$grp
979	}	1223	}
980		1224
981	=item aio_rmtree $path, $callback->($status)	1225	=item aio_rmtree $pathname, $callback->($status)
982		1226
983	Delete a directory tree starting (and including) C<$path>, return the	1227	Delete a directory tree starting (and including) C<$path>, return the
984	status of the final C<rmdir> only. This is a composite request that	1228	status of the final C<rmdir> only. This is a composite request that
985	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1229	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
986	everything else.	1230	everything else.
987		1231
988	=cut	1232	=cut
989		1233
…		…
1011	};	1255	};
1012		1256
1013	$grp	1257	$grp
1014	}	1258	}
1015		1259
		1260	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1261
		1262	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1263
		1264	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1265	they execute asynchronously and pass the return value to the callback.
		1266
		1267	Both calls can be used for a lot of things, some of which make more sense
		1268	to run asynchronously in their own thread, while some others make less
		1269	sense. For example, calls that block waiting for external events, such
		1270	as locking, will also lock down an I/O thread while it is waiting, which
		1271	can deadlock the whole I/O system. At the same time, there might be no
		1272	alternative to using a thread to wait.
		1273
		1274	So in general, you should only use these calls for things that do
		1275	(filesystem) I/O, not for things that wait for other events (network,
		1276	other processes), although if you are careful and know what you are doing,
		1277	you still can.
		1278
		1279	The following constants are available (missing ones are, as usual C<0>):
		1280
		1281	C<F_DUPFD_CLOEXEC>,
		1282
		1283	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1284
		1285	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1286
		1287	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1288	C<FS_IOC_FIEMAP>.
		1289
		1290	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1291	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1292
		1293	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1294	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1295	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1296	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1297	C<FS_FL_USER_MODIFIABLE>.
		1298
		1299	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1300	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1301	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1302	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
		1303
1016	=item aio_sync $callback->($status)	1304	=item aio_sync $callback->($status)
1017		1305
1018	Asynchronously call sync and call the callback when finished.	1306	Asynchronously call sync and call the callback when finished.
1019		1307
1020	=item aio_fsync $fh, $callback->($status)	1308	=item aio_fsync $fh, $callback->($status)
…		…
1027	Asynchronously call fdatasync on the given filehandle and call the	1315	Asynchronously call fdatasync on the given filehandle and call the
1028	callback with the fdatasync result code.	1316	callback with the fdatasync result code.
1029		1317
1030	If this call isn't available because your OS lacks it or it couldn't be	1318	If this call isn't available because your OS lacks it or it couldn't be
1031	detected, it will be emulated by calling C<fsync> instead.	1319	detected, it will be emulated by calling C<fsync> instead.
		1320
		1321	=item aio_syncfs $fh, $callback->($status)
		1322
		1323	Asynchronously call the syncfs syscall to sync the filesystem associated
		1324	to the given filehandle and call the callback with the syncfs result
		1325	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1326	errno to C<ENOSYS> nevertheless.
1032		1327
1033	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1328	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1034		1329
1035	Sync the data portion of the file specified by C<$offset> and C<$length>	1330	Sync the data portion of the file specified by C<$offset> and C<$length>
1036	to disk (but NOT the metadata), by calling the Linux-specific	1331	to disk (but NOT the metadata), by calling the Linux-specific
…		…
1040	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1335	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1041	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1336	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1042	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1337	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1043	manpage for details.	1338	manpage for details.
1044		1339
1045	=item aio_pathsync $path, $callback->($status)	1340	=item aio_pathsync $pathname, $callback->($status)
1046		1341
1047	This request tries to open, fsync and close the given path. This is a	1342	This request tries to open, fsync and close the given path. This is a
1048	composite request intended to sync directories after directory operations	1343	composite request intended to sync directories after directory operations
1049	(E.g. rename). This might not work on all operating systems or have any	1344	(E.g. rename). This might not work on all operating systems or have any
1050	specific effect, but usually it makes sure that directory changes get	1345	specific effect, but usually it makes sure that directory changes get
…		…
1081	};	1376	};
1082		1377
1083	$grp	1378	$grp
1084	}	1379	}
1085		1380
1086	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1381	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1087		1382
1088	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1383	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1089	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1384	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1090	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1385	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1091	scalar must only be modified in-place while an aio operation is pending on	1386	scalar must only be modified in-place while an aio operation is pending on
…		…
1093		1388
1094	It calls the C<msync> function of your OS, if available, with the memory	1389	It calls the C<msync> function of your OS, if available, with the memory
1095	area starting at C<$offset> in the string and ending C<$length> bytes	1390	area starting at C<$offset> in the string and ending C<$length> bytes
1096	later. If C<$length> is negative, counts from the end, and if C<$length>	1391	later. If C<$length> is negative, counts from the end, and if C<$length>
1097	is C<undef>, then it goes till the end of the string. The flags can be	1392	is C<undef>, then it goes till the end of the string. The flags can be
1098	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1393	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1099	C<IO::AIO::MS_SYNC>.	1394	C<IO::AIO::MS_INVALIDATE>.
1100		1395
1101	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1396	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1102		1397
1103	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1398	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1104	scalars.	1399	scalars.
1105		1400
1106	It touches (reads or writes) all memory pages in the specified	1401	It touches (reads or writes) all memory pages in the specified
1107	range inside the scalar. All caveats and parameters are the same	1402	range inside the scalar. All caveats and parameters are the same
1108	as for C<aio_msync>, above, except for flags, which must be either	1403	as for C<aio_msync>, above, except for flags, which must be either
1109	C<0> (which reads all pages and ensures they are instantiated) or	1404	C<0> (which reads all pages and ensures they are instantiated) or
1110	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1405	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1111	writing an octet from it, which dirties the page).	1406	writing an octet from it, which dirties the page).
		1407
		1408	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1409
		1410	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1411	scalars.
		1412
		1413	It reads in all the pages of the underlying storage into memory (if any)
		1414	and locks them, so they are not getting swapped/paged out or removed.
		1415
		1416	If C<$length> is undefined, then the scalar will be locked till the end.
		1417
		1418	On systems that do not implement C<mlock>, this function returns C<-1>
		1419	and sets errno to C<ENOSYS>.
		1420
		1421	Note that the corresponding C<munlock> is synchronous and is
		1422	documented under L<MISCELLANEOUS FUNCTIONS>.
		1423
		1424	Example: open a file, mmap and mlock it - both will be undone when
		1425	C<$data> gets destroyed.
		1426
		1427	open my $fh, "<", $path or die "$path: $!";
		1428	my $data;
		1429	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1430	aio_mlock $data; # mlock in background
		1431
		1432	=item aio_mlockall $flags, $callback->($status)
		1433
		1434	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1435	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1436
		1437	On systems that do not implement C<mlockall>, this function returns C<-1>
		1438	and sets errno to C<ENOSYS>.
		1439
		1440	Note that the corresponding C<munlockall> is synchronous and is
		1441	documented under L<MISCELLANEOUS FUNCTIONS>.
		1442
		1443	Example: asynchronously lock all current and future pages into memory.
		1444
		1445	aio_mlockall IO::AIO::MCL_FUTURE;
		1446
		1447	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1448
		1449	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1450	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1451	the ioctl is not available on your OS, then this request will fail with
		1452	C<ENOSYS>.
		1453
		1454	C<$start> is the starting offset to query extents for, C<$length> is the
		1455	size of the range to query - if it is C<undef>, then the whole file will
		1456	be queried.
		1457
		1458	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1459	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1460	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1461	the data portion.
		1462
		1463	C<$count> is the maximum number of extent records to return. If it is
		1464	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1465	case, if it is C<0>, then the callback receives the number of extents
		1466	instead of the extents themselves (which is unreliable, see below).
		1467
		1468	If an error occurs, the callback receives no arguments. The special
		1469	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1470
		1471	Otherwise, the callback receives an array reference with extent
		1472	structures. Each extent structure is an array reference itself, with the
		1473	following members:
		1474
		1475	[$logical, $physical, $length, $flags]
		1476
		1477	Flags is any combination of the following flag values (typically either C<0>
		1478	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1479
		1480	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1481	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1482	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1483	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1484	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1485	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1486
		1487	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1488	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1489	it to return all extents of a range for files with large number of
		1490	extents. The code works around all these issues if C<$count> is undef.
1112		1491
1113	=item aio_group $callback->(...)	1492	=item aio_group $callback->(...)
1114		1493
1115	This is a very special aio request: Instead of doing something, it is a	1494	This is a very special aio request: Instead of doing something, it is a
1116	container for other aio requests, which is useful if you want to bundle	1495	container for other aio requests, which is useful if you want to bundle
…		…
1153	like sleep and file handle readable/writable, the overhead this creates is	1532	like sleep and file handle readable/writable, the overhead this creates is
1154	immense (it blocks a thread for a long time) so do not use this function	1533	immense (it blocks a thread for a long time) so do not use this function
1155	except to put your application under artificial I/O pressure.	1534	except to put your application under artificial I/O pressure.
1156		1535
1157	=back	1536	=back
		1537
		1538
		1539	=head2 IO::AIO::WD - multiple working directories
		1540
		1541	Your process only has one current working directory, which is used by all
		1542	threads. This makes it hard to use relative paths (some other component
		1543	could call C<chdir> at any time, and it is hard to control when the path
		1544	will be used by IO::AIO).
		1545
		1546	One solution for this is to always use absolute paths. This usually works,
		1547	but can be quite slow (the kernel has to walk the whole path on every
		1548	access), and can also be a hassle to implement.
		1549
		1550	Newer POSIX systems have a number of functions (openat, fdopendir,
		1551	futimensat and so on) that make it possible to specify working directories
		1552	per operation.
		1553
		1554	For portability, and because the clowns who "designed", or shall I write,
		1555	perpetrated this new interface were obviously half-drunk, this abstraction
		1556	cannot be perfect, though.
		1557
		1558	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1559	object. This object stores the canonicalised, absolute version of the
		1560	path, and on systems that allow it, also a directory file descriptor.
		1561
		1562	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1563	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1564	object and a pathname instead (or the IO::AIO::WD object alone, which
		1565	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1566	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1567	to that IO::AIO::WD object.
		1568
		1569	For example, to get a wd object for F</etc> and then stat F<passwd>
		1570	inside, you would write:
		1571
		1572	aio_wd "/etc", sub {
		1573	my $etcdir = shift;
		1574
		1575	# although $etcdir can be undef on error, there is generally no reason
		1576	# to check for errors here, as aio_stat will fail with ENOENT
		1577	# when $etcdir is undef.
		1578
		1579	aio_stat [$etcdir, "passwd"], sub {
		1580	# yay
		1581	};
		1582	};
		1583
		1584	The fact that C<aio_wd> is a request and not a normal function shows that
		1585	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1586	which is why it is done asynchronously.
		1587
		1588	To stat the directory obtained with C<aio_wd> above, one could write
		1589	either of the following three request calls:
		1590
		1591	aio_lstat "/etc" , sub { ... # pathname as normal string
		1592	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1593	aio_lstat $wd , sub { ... # shorthand for the previous
		1594
		1595	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1596	object and the pathname string, so you could write the following without
		1597	causing any issues due to C<$path> getting reused:
		1598
		1599	my $path = [$wd, undef];
		1600
		1601	for my $name (qw(abc def ghi)) {
		1602	$path->[1] = $name;
		1603	aio_stat $path, sub {
		1604	# ...
		1605	};
		1606	}
		1607
		1608	There are some caveats: when directories get renamed (or deleted), the
		1609	pathname string doesn't change, so will point to the new directory (or
		1610	nowhere at all), while the directory fd, if available on the system,
		1611	will still point to the original directory. Most functions accepting a
		1612	pathname will use the directory fd on newer systems, and the string on
		1613	older systems. Some functions (such as realpath) will always rely on the
		1614	string form of the pathname.
		1615
		1616	So this functionality is mainly useful to get some protection against
		1617	C<chdir>, to easily get an absolute path out of a relative path for future
		1618	reference, and to speed up doing many operations in the same directory
		1619	(e.g. when stat'ing all files in a directory).
		1620
		1621	The following functions implement this working directory abstraction:
		1622
		1623	=over 4
		1624
		1625	=item aio_wd $pathname, $callback->($wd)
		1626
		1627	Asynchonously canonicalise the given pathname and convert it to an
		1628	IO::AIO::WD object representing it. If possible and supported on the
		1629	system, also open a directory fd to speed up pathname resolution relative
		1630	to this working directory.
		1631
		1632	If something goes wrong, then C<undef> is passwd to the callback instead
		1633	of a working directory object and C<$!> is set appropriately. Since
		1634	passing C<undef> as working directory component of a pathname fails the
		1635	request with C<ENOENT>, there is often no need for error checking in the
		1636	C<aio_wd> callback, as future requests using the value will fail in the
		1637	expected way.
		1638
		1639	=item IO::AIO::CWD
		1640
		1641	This is a compiletime constant (object) that represents the process
		1642	current working directory.
		1643
		1644	Specifying this object as working directory object for a pathname is as if
		1645	the pathname would be specified directly, without a directory object. For
		1646	example, these calls are functionally identical:
		1647
		1648	aio_stat "somefile", sub { ... };
		1649	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1650
		1651	=back
		1652
		1653	To recover the path associated with an IO::AIO::WD object, you can use
		1654	C<aio_realpath>:
		1655
		1656	aio_realpath $wd, sub {
		1657	warn "path is $_[0]\n";
		1658	};
		1659
		1660	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1661	sometimes, fall back to using an absolue path.
1158		1662
1159	=head2 IO::AIO::REQ CLASS	1663	=head2 IO::AIO::REQ CLASS
1160		1664
1161	All non-aggregate C<aio_*> functions return an object of this class when	1665	All non-aggregate C<aio_*> functions return an object of this class when
1162	called in non-void context.	1666	called in non-void context.
…		…
1280		1784
1281	Sets a feeder/generator on this group: every group can have an attached	1785	Sets a feeder/generator on this group: every group can have an attached
1282	generator that generates requests if idle. The idea behind this is that,	1786	generator that generates requests if idle. The idea behind this is that,
1283	although you could just queue as many requests as you want in a group,	1787	although you could just queue as many requests as you want in a group,
1284	this might starve other requests for a potentially long time. For example,	1788	this might starve other requests for a potentially long time. For example,
1285	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1789	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1286	delaying any later requests for a long time.	1790	requests, delaying any later requests for a long time.
1287		1791
1288	To avoid this, and allow incremental generation of requests, you can	1792	To avoid this, and allow incremental generation of requests, you can
1289	instead a group and set a feeder on it that generates those requests. The	1793	instead a group and set a feeder on it that generates those requests. The
1290	feed callback will be called whenever there are few enough (see C<limit>,	1794	feed callback will be called whenever there are few enough (see C<limit>,
1291	below) requests active in the group itself and is expected to queue more	1795	below) requests active in the group itself and is expected to queue more
…		…
1340		1844
1341	See C<poll_cb> for an example.	1845	See C<poll_cb> for an example.
1342		1846
1343	=item IO::AIO::poll_cb	1847	=item IO::AIO::poll_cb
1344		1848
1345	Process some outstanding events on the result pipe. You have to call this	1849	Process some requests that have reached the result phase (i.e. they have
1346	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1850	been executed but the results are not yet reported). You have to call
1347	returned earlier for whatever reason. Returns immediately when no events	1851	this "regularly" to finish outstanding requests.
1348	are outstanding. The amount of events processed depends on the settings of
1349	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1350		1852
		1853	Returns C<0> if all events could be processed (or there were no
		1854	events to process), or C<-1> if it returned earlier for whatever
		1855	reason. Returns immediately when no events are outstanding. The amount
		1856	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
		1857	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
		1858
1351	If not all requests were processed for whatever reason, the filehandle	1859	If not all requests were processed for whatever reason, the poll file
1352	will still be ready when C<poll_cb> returns, so normally you don't have to	1860	descriptor will still be ready when C<poll_cb> returns, so normally you
1353	do anything special to have it called later.	1861	don't have to do anything special to have it called later.
		1862
		1863	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1864	ready, it can be beneficial to call this function from loops which submit
		1865	a lot of requests, to make sure the results get processed when they become
		1866	available and not just when the loop is finished and the event loop takes
		1867	over again. This function returns very fast when there are no outstanding
		1868	requests.
1354		1869
1355	Example: Install an Event watcher that automatically calls	1870	Example: Install an Event watcher that automatically calls
1356	IO::AIO::poll_cb with high priority (more examples can be found in the	1871	IO::AIO::poll_cb with high priority (more examples can be found in the
1357	SYNOPSIS section, at the top of this document):	1872	SYNOPSIS section, at the top of this document):
1358		1873
…		…
1360	poll => 'r', async => 1,	1875	poll => 'r', async => 1,
1361	cb => \&IO::AIO::poll_cb);	1876	cb => \&IO::AIO::poll_cb);
1362		1877
1363	=item IO::AIO::poll_wait	1878	=item IO::AIO::poll_wait
1364		1879
1365	If there are any outstanding requests and none of them in the result	1880	Wait until either at least one request is in the result phase or no
1366	phase, wait till the result filehandle becomes ready for reading (simply	1881	requests are outstanding anymore.
1367	does a C<select> on the filehandle. This is useful if you want to	1882
1368	synchronously wait for some requests to finish).	1883	This is useful if you want to synchronously wait for some requests to
		1884	become ready, without actually handling them.
1369		1885
1370	See C<nreqs> for an example.	1886	See C<nreqs> for an example.
1371		1887
1372	=item IO::AIO::poll	1888	=item IO::AIO::poll
1373		1889
…		…
1460		1976
1461	Under normal circumstances you don't need to call this function.	1977	Under normal circumstances you don't need to call this function.
1462		1978
1463	=item IO::AIO::max_idle $nthreads	1979	=item IO::AIO::max_idle $nthreads
1464		1980
1465	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1981	Limit the number of threads (default: 4) that are allowed to idle
1466	threads that did not get a request to process within 10 seconds). That	1982	(i.e., threads that did not get a request to process within the idle
1467	means if a thread becomes idle while C<$nthreads> other threads are also	1983	timeout (default: 10 seconds). That means if a thread becomes idle while
1468	idle, it will free its resources and exit.	1984	C<$nthreads> other threads are also idle, it will free its resources and
		1985	exit.
1469		1986
1470	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1987	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1471	to allow for extremely high load situations, but want to free resources	1988	to allow for extremely high load situations, but want to free resources
1472	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1989	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1473		1990
1474	The default is probably ok in most situations, especially if thread	1991	The default is probably ok in most situations, especially if thread
1475	creation is fast. If thread creation is very slow on your system you might	1992	creation is fast. If thread creation is very slow on your system you might
1476	want to use larger values.	1993	want to use larger values.
1477		1994
		1995	=item IO::AIO::idle_timeout $seconds
		1996
		1997	Sets the minimum idle timeout (default 10) after which worker threads are
		1998	allowed to exit. SEe C<IO::AIO::max_idle>.
		1999
1478	=item IO::AIO::max_outstanding $maxreqs	2000	=item IO::AIO::max_outstanding $maxreqs
		2001
		2002	Sets the maximum number of outstanding requests to C<$nreqs>. If
		2003	you do queue up more than this number of requests, the next call to
		2004	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		2005	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		2006	longer exceeded.
		2007
		2008	In other words, this setting does not enforce a queue limit, but can be
		2009	used to make poll functions block if the limit is exceeded.
1479		2010
1480	This is a very bad function to use in interactive programs because it	2011	This is a very bad function to use in interactive programs because it
1481	blocks, and a bad way to reduce concurrency because it is inexact: Better	2012	blocks, and a bad way to reduce concurrency because it is inexact: Better
1482	use an C<aio_group> together with a feed callback.	2013	use an C<aio_group> together with a feed callback.
1483		2014
1484	Sets the maximum number of outstanding requests to C<$nreqs>. If you	2015	Its main use is in scripts without an event loop - when you want to stat
1485	do queue up more than this number of requests, the next call to the	2016	a lot of files, you can write something like this:
1486	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1487	function will block until the limit is no longer exceeded.
1488		2017
1489	The default value is very large, so there is no practical limit on the	2018	IO::AIO::max_outstanding 32;
1490	number of outstanding requests.
1491		2019
1492	You can still queue as many requests as you want. Therefore,	2020	for my $path (...) {
1493	C<max_outstanding> is mainly useful in simple scripts (with low values) or	2021	aio_stat $path , ...;
1494	as a stop gap to shield against fatal memory overflow (with large values).	2022	IO::AIO::poll_cb;
		2023	}
		2024
		2025	IO::AIO::flush;
		2026
		2027	The call to C<poll_cb> inside the loop will normally return instantly, but
		2028	as soon as more thna C<32> reqeusts are in-flight, it will block until
		2029	some requests have been handled. This keeps the loop from pushing a large
		2030	number of C<aio_stat> requests onto the queue.
		2031
		2032	The default value for C<max_outstanding> is very large, so there is no
		2033	practical limit on the number of outstanding requests.
1495		2034
1496	=back	2035	=back
1497		2036
1498	=head3 STATISTICAL INFORMATION	2037	=head3 STATISTICAL INFORMATION
1499		2038
…		…
1521		2060
1522	=back	2061	=back
1523		2062
1524	=head3 MISCELLANEOUS FUNCTIONS	2063	=head3 MISCELLANEOUS FUNCTIONS
1525		2064
1526	IO::AIO implements some functions that might be useful, but are not	2065	IO::AIO implements some functions that are useful when you want to use
1527	asynchronous.	2066	some "Advanced I/O" function not available to in Perl, without going the
		2067	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2068	counterpart.
1528		2069
1529	=over 4	2070	=over 4
		2071
		2072	=item $numfd = IO::AIO::get_fdlimit
		2073
		2074	Tries to find the current file descriptor limit and returns it, or
		2075	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2076	the highest valid file descriptor number.
		2077
		2078	=item IO::AIO::min_fdlimit [$numfd]
		2079
		2080	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2081	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2082	is missing, it will try to set a very high limit, although this is not
		2083	recommended when you know the actual minimum that you require.
		2084
		2085	If the limit cannot be raised enough, the function makes a best-effort
		2086	attempt to increase the limit as much as possible, using various
		2087	tricks, while still failing. You can query the resulting limit using
		2088	C<IO::AIO::get_fdlimit>.
		2089
		2090	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2091	true.
1530		2092
1531	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2093	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1532		2094
1533	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2095	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1534	but is blocking (this makes most sense if you know the input data is	2096	but is blocking (this makes most sense if you know the input data is
…		…
1537		2099
1538	Returns the number of bytes copied, or C<-1> on error.	2100	Returns the number of bytes copied, or C<-1> on error.
1539		2101
1540	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2102	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1541		2103
1542	Simply calls the C<posix_fadvise> function (see it's	2104	Simply calls the C<posix_fadvise> function (see its
1543	manpage for details). The following advice constants are	2105	manpage for details). The following advice constants are
1544	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2106	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1545	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2107	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1546	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2108	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1547		2109
1548	On systems that do not implement C<posix_fadvise>, this function returns	2110	On systems that do not implement C<posix_fadvise>, this function returns
1549	ENOSYS, otherwise the return value of C<posix_fadvise>.	2111	ENOSYS, otherwise the return value of C<posix_fadvise>.
1550		2112
		2113	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		2114
		2115	Simply calls the C<posix_madvise> function (see its
		2116	manpage for details). The following advice constants are
		2117	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		2118	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2119	C<IO::AIO::MADV_DONTNEED>.
		2120
		2121	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2122	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2123	will be reduced to fit into the C<$scalar>.
		2124
		2125	On systems that do not implement C<posix_madvise>, this function returns
		2126	ENOSYS, otherwise the return value of C<posix_madvise>.
		2127
		2128	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		2129
		2130	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		2131	$scalar (see its manpage for details). The following protect
		2132	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		2133	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		2134
		2135	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2136	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2137	will be reduced to fit into the C<$scalar>.
		2138
		2139	On systems that do not implement C<mprotect>, this function returns
		2140	ENOSYS, otherwise the return value of C<mprotect>.
		2141
1551	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2142	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1552		2143
1553	Memory-maps a file (or anonymous memory range) and attaches it to the	2144	Memory-maps a file (or anonymous memory range) and attaches it to the
1554	given C<$scalar>, which will act like a string scalar.	2145	given C<$scalar>, which will act like a string scalar. Returns true on
		2146	success, and false otherwise.
1555		2147
		2148	The scalar must exist, but its contents do not matter - this means you
		2149	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2150	the scalar first.
		2151
1556	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2152	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1557	change the string length, and most read-only operations such as copying it	2153	which don't change the string length, and most read-only operations such
1558	or searching it with regexes and so on.	2154	as copying it or searching it with regexes and so on.
1559		2155
1560	Anything else is unsafe and will, at best, result in memory leaks.	2156	Anything else is unsafe and will, at best, result in memory leaks.
1561		2157
1562	The memory map associated with the C<$scalar> is automatically removed	2158	The memory map associated with the C<$scalar> is automatically removed
1563	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2159	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1564	C<IO::AIO::munmap> functions are called.	2160	or C<IO::AIO::munmap> functions are called on it.
1565		2161
1566	This calls the C<mmap>(2) function internally. See your system's manual	2162	This calls the C<mmap>(2) function internally. See your system's manual
1567	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2163	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1568		2164
1569	The C<$length> must be larger than zero and smaller than the actual	2165	The C<$length> must be larger than zero and smaller than the actual
1570	filesize.	2166	filesize.
1571		2167
1572	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2168	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1573	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2169	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1574		2170
1575	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2171	C<$flags> can be a combination of
1576	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2172	C<IO::AIO::MAP_SHARED> or
1577	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2173	C<IO::AIO::MAP_PRIVATE>,
		2174	or a number of system-specific flags (when not available, the are C<0>):
1578	(which is set to C<MAP_ANON> if your system only provides this	2175	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1579	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2176	C<IO::AIO::MAP_LOCKED>,
1580	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2177	C<IO::AIO::MAP_NORESERVE>,
		2178	C<IO::AIO::MAP_POPULATE>,
1581	C<IO::AIO::MAP_NONBLOCK>	2179	C<IO::AIO::MAP_NONBLOCK>,
		2180	C<IO::AIO::MAP_FIXED>,
		2181	C<IO::AIO::MAP_GROWSDOWN>,
		2182	C<IO::AIO::MAP_32BIT>,
		2183	C<IO::AIO::MAP_HUGETLB> or
		2184	C<IO::AIO::MAP_STACK>.
1582		2185
1583	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2186	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1584		2187
1585	C<$offset> is the offset from the start of the file - it generally must be	2188	C<$offset> is the offset from the start of the file - it generally must be
1586	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2189	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1600		2203
1601	=item IO::AIO::munmap $scalar	2204	=item IO::AIO::munmap $scalar
1602		2205
1603	Removes a previous mmap and undefines the C<$scalar>.	2206	Removes a previous mmap and undefines the C<$scalar>.
1604		2207
1605	=item IO::AIO::mlockall $flags	2208	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1606		2209
1607	Calls the C<mlockall> function with the given C<$flags> (a combination of	2210	Calls the C<munlock> function, undoing the effects of a previous
1608	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL__FUTURE>).	2211	C<aio_mlock> call (see its description for details).
1609
1610	On systems that do not implement C<mlockall>, this function returns
1611	ENOSYS, otherwise the return value of C<mlockall>.
1612		2212
1613	=item IO::AIO::munlockall	2213	=item IO::AIO::munlockall
1614		2214
1615	Calls the C<munlockall> function.	2215	Calls the C<munlockall> function.
1616		2216
1617	On systems that do not implement C<munlockall>, this function returns	2217	On systems that do not implement C<munlockall>, this function returns
1618	ENOSYS, otherwise the return value of C<munlockall>.	2218	ENOSYS, otherwise the return value of C<munlockall>.
		2219
		2220	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2221
		2222	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2223	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2224	should be the file offset.
		2225
		2226	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2227	silently corrupt the data in this case.
		2228
		2229	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2230	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2231	C<IO::AIO::SPLICE_F_GIFT>.
		2232
		2233	See the C<splice(2)> manpage for details.
		2234
		2235	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2236
		2237	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2238	description for C<IO::AIO::splice> above for details.
		2239
		2240	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2241
		2242	Attempts to query or change the pipe buffer size. Obviously works only
		2243	on pipes, and currently works only on GNU/Linux systems, and fails with
		2244	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2245	size on other systems, drop me a note.
		2246
		2247	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2248
		2249	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2250	C<$flags> is missing or C<0>, then this should be the same as a call to
		2251	perl's built-in C<pipe> function and create a new pipe, and works on
		2252	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2253	(..., 4096, O_BINARY)>.
		2254
		2255	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2256	the given flags (Linux 2.6.27, glibc 2.9).
		2257
		2258	On success, the read and write file handles are returned.
		2259
		2260	On error, nothing will be returned. If the pipe2 syscall is missing and
		2261	C<$flags> is non-zero, fails with C<ENOSYS>.
		2262
		2263	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2264	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2265	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1619		2266
1620	=back	2267	=back
1621		2268
1622	=cut	2269	=cut
1623		2270
…		…
1658	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2305	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1659	\&IO::AIO::poll_cb);	2306	\&IO::AIO::poll_cb);
1660		2307
1661	=head2 FORK BEHAVIOUR	2308	=head2 FORK BEHAVIOUR
1662		2309
1663	This module should do "the right thing" when the process using it forks:	2310	Usage of pthreads in a program changes the semantics of fork
		2311	considerably. Specifically, only async-safe functions can be called after
		2312	fork. Perl doesn't know about this, so in general, you cannot call fork
		2313	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2314	pthreads, so this applies, but many other extensions and (for inexplicable
		2315	reasons) perl itself often is linked against pthreads, so this limitation
		2316	applies to quite a lot of perls.
1664		2317
1665	Before the fork, IO::AIO enters a quiescent state where no requests	2318	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1666	can be added in other threads and no results will be processed. After	2319	only works in the process that loaded it. Forking is fully supported, but
1667	the fork the parent simply leaves the quiescent state and continues	2320	using IO::AIO in the child is not.
1668	request/result processing, while the child frees the request/result queue
1669	(so that the requests started before the fork will only be handled in the
1670	parent). Threads will be started on demand until the limit set in the
1671	parent process has been reached again.
1672		2321
1673	In short: the parent will, after a short pause, continue as if fork had	2322	You might get around by not I<using> IO::AIO before (or after)
1674	not been called, while the child will act as if IO::AIO has not been used	2323	forking. You could also try to call the L<IO::AIO::reinit> function in the
1675	yet.	2324	child:
		2325
		2326	=over 4
		2327
		2328	=item IO::AIO::reinit
		2329
		2330	Abandons all current requests and I/O threads and simply reinitialises all
		2331	data structures. This is not an operation supported by any standards, but
		2332	happens to work on GNU/Linux and some newer BSD systems.
		2333
		2334	The only reasonable use for this function is to call it after forking, if
		2335	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2336	the process will result in undefined behaviour. Calling it at any time
		2337	will also result in any undefined (by POSIX) behaviour.
		2338
		2339	=back
1676		2340
1677	=head2 MEMORY USAGE	2341	=head2 MEMORY USAGE
1678		2342
1679	Per-request usage:	2343	Per-request usage:
1680		2344

Diff Legend

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