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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.193 by root, Thu May 26 04:15:37 2011 UTC vs.
Revision 1.273 by root, Fri Jun 23 22:33:06 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 = '3.8';	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_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
183	aio_statvfs);	187	aio_statvfs
		188	aio_wd);
184		189
185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	190	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	191	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
187	min_parallel max_parallel max_idle idle_timeout	192	min_parallel max_parallel max_idle idle_timeout
188	nreqs nready npending nthreads	193	nreqs nready npending nthreads
…		…
200		205
201	=head1 FUNCTIONS	206	=head1 FUNCTIONS
202		207
203	=head2 QUICK OVERVIEW	208	=head2 QUICK OVERVIEW
204		209
205	This section simply lists the prototypes of the most important functions	210	This section simply lists the prototypes most of the functions for
206	for quick reference. See the following sections for function-by-function	211	quick reference. See the following sections for function-by-function
207	documentation.	212	documentation.
208		213
		214	aio_wd $pathname, $callback->($wd)
209	aio_open $pathname, $flags, $mode, $callback->($fh)	215	aio_open $pathname, $flags, $mode, $callback->($fh)
210	aio_close $fh, $callback->($status)	216	aio_close $fh, $callback->($status)
		217	aio_seek $fh,$offset,$whence, $callback->($offs)
211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	218	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	219	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	220	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214	aio_readahead $fh,$offset,$length, $callback->($retval)	221	aio_readahead $fh,$offset,$length, $callback->($retval)
215	aio_stat $fh_or_path, $callback->($status)	222	aio_stat $fh_or_path, $callback->($status)
216	aio_lstat $fh, $callback->($status)	223	aio_lstat $fh, $callback->($status)
217	aio_statvfs $fh_or_path, $callback->($statvfs)	224	aio_statvfs $fh_or_path, $callback->($statvfs)
218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	225	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219	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)
220	aio_truncate $fh_or_path, $offset, $callback->($status)	228	aio_truncate $fh_or_path, $offset, $callback->($status)
221	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)
222	aio_unlink $pathname, $callback->($status)	231	aio_unlink $pathname, $callback->($status)
223	aio_mknod $path, $mode, $dev, $callback->($status)	232	aio_mknod $pathname, $mode, $dev, $callback->($status)
224	aio_link $srcpath, $dstpath, $callback->($status)	233	aio_link $srcpath, $dstpath, $callback->($status)
225	aio_symlink $srcpath, $dstpath, $callback->($status)	234	aio_symlink $srcpath, $dstpath, $callback->($status)
226	aio_readlink $path, $callback->($link)	235	aio_readlink $pathname, $callback->($link)
		236	aio_realpath $pathname, $callback->($path)
227	aio_rename $srcpath, $dstpath, $callback->($status)	237	aio_rename $srcpath, $dstpath, $callback->($status)
		238	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
228	aio_mkdir $pathname, $mode, $callback->($status)	239	aio_mkdir $pathname, $mode, $callback->($status)
229	aio_rmdir $pathname, $callback->($status)	240	aio_rmdir $pathname, $callback->($status)
230	aio_readdir $pathname, $callback->($entries)	241	aio_readdir $pathname, $callback->($entries)
231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	242	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	243	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233	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)
234	aio_load $path, $data, $callback->($status)	246	aio_load $pathname, $data, $callback->($status)
235	aio_copy $srcpath, $dstpath, $callback->($status)	247	aio_copy $srcpath, $dstpath, $callback->($status)
236	aio_move $srcpath, $dstpath, $callback->($status)	248	aio_move $srcpath, $dstpath, $callback->($status)
237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238	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)
239	aio_sync $callback->($status)	252	aio_sync $callback->($status)
		253	aio_syncfs $fh, $callback->($status)
240	aio_fsync $fh, $callback->($status)	254	aio_fsync $fh, $callback->($status)
241	aio_fdatasync $fh, $callback->($status)	255	aio_fdatasync $fh, $callback->($status)
242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	256	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243	aio_pathsync $path, $callback->($status)	257	aio_pathsync $pathname, $callback->($status)
244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	258	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	260	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247	aio_mlockall $flags, $callback->($status)	261	aio_mlockall $flags, $callback->($status)
248	aio_group $callback->(...)	262	aio_group $callback->(...)
249	aio_nop $callback->()	263	aio_nop $callback->()
…		…
266	IO::AIO::nready	280	IO::AIO::nready
267	IO::AIO::npending	281	IO::AIO::npending
268		282
269	IO::AIO::sendfile $ofh, $ifh, $offset, $count	283	IO::AIO::sendfile $ofh, $ifh, $offset, $count
270	IO::AIO::fadvise $fh, $offset, $len, $advice	284	IO::AIO::fadvise $fh, $offset, $len, $advice
		285	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		286	IO::AIO::munmap $scalar
271	IO::AIO::madvise $scalar, $offset, $length, $advice	287	IO::AIO::madvise $scalar, $offset, $length, $advice
272	IO::AIO::mprotect $scalar, $offset, $length, $protect	288	IO::AIO::mprotect $scalar, $offset, $length, $protect
273	IO::AIO::munlock $scalar, $offset = 0, $length = undef	289	IO::AIO::munlock $scalar, $offset = 0, $length = undef
274	IO::AIO::munlockall	290	IO::AIO::munlockall
275		291
276	=head2 AIO REQUEST FUNCTIONS	292	=head2 API NOTES
277		293
278	All the C<aio_*> calls are more or less thin wrappers around the syscall	294	All the C<aio_*> calls are more or less thin wrappers around the syscall
279	with the same name (sans C<aio_>). The arguments are similar or identical,	295	with the same name (sans C<aio_>). The arguments are similar or identical,
280	and they all accept an additional (and optional) C<$callback> argument	296	and they all accept an additional (and optional) C<$callback> argument
281	which must be a code reference. This code reference will get called with	297	which must be a code reference. This code reference will be called after
282	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	298	the syscall has been executed in an asynchronous fashion. The results
283	perl, which usually delivers "false") as its sole argument after the given	299	of the request will be passed as arguments to the callback (and, if an
284	syscall has been executed asynchronously.	300	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		301	most syscalls return C<-1> on error, unlike perl, which usually delivers
		302	"false").
		303
		304	Some requests (such as C<aio_readdir>) pass the actual results and
		305	communicate failures by passing C<undef>.
285		306
286	All functions expecting a filehandle keep a copy of the filehandle	307	All functions expecting a filehandle keep a copy of the filehandle
287	internally until the request has finished.	308	internally until the request has finished.
288		309
289	All functions return request objects of type L<IO::AIO::REQ> that allow	310	All functions return request objects of type L<IO::AIO::REQ> that allow
290	further manipulation of those requests while they are in-flight.	311	further manipulation of those requests while they are in-flight.
291		312
292	The pathnames you pass to these routines I<must> be absolute and	313	The pathnames you pass to these routines I<should> be absolute. The
293	encoded as octets. The reason for the former is that at the time the	314	reason for this is that at the time the request is being executed, the
294	request is being executed, the current working directory could have	315	current working directory could have changed. Alternatively, you can
295	changed. Alternatively, you can make sure that you never change the	316	make sure that you never change the current working directory anywhere
296	current working directory anywhere in the program and then use relative	317	in the program and then use relative paths. You can also take advantage
297	paths.	318	of IO::AIOs working directory abstraction, that lets you specify paths
		319	relative to some previously-opened "working directory object" - see the
		320	description of the C<IO::AIO::WD> class later in this document.
298		321
299	To encode pathnames as octets, either make sure you either: a) always pass	322	To encode pathnames as octets, either make sure you either: a) always pass
300	in filenames you got from outside (command line, readdir etc.) without	323	in filenames you got from outside (command line, readdir etc.) without
301	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	324	tinkering, b) are in your native filesystem encoding, c) use the Encode
302	your pathnames to the locale (or other) encoding in effect in the user	325	module and encode your pathnames to the locale (or other) encoding in
303	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	326	effect in the user environment, d) use Glib::filename_from_unicode on
304	use something else to ensure your scalar has the correct contents.	327	unicode filenames or e) use something else to ensure your scalar has the
		328	correct contents.
305		329
306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	330	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
307	handles correctly whether it is set or not.	331	handles correctly whether it is set or not.
		332
		333	=head2 AIO REQUEST FUNCTIONS
308		334
309	=over 4	335	=over 4
310		336
311	=item $prev_pri = aioreq_pri [$pri]	337	=item $prev_pri = aioreq_pri [$pri]
312		338
…		…
342		368
343		369
344	=item aio_open $pathname, $flags, $mode, $callback->($fh)	370	=item aio_open $pathname, $flags, $mode, $callback->($fh)
345		371
346	Asynchronously open or create a file and call the callback with a newly	372	Asynchronously open or create a file and call the callback with a newly
347	created filehandle for the file.	373	created filehandle for the file (or C<undef> in case of an error).
348		374
349	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	375	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
350	for an explanation.	376	for an explanation.
351		377
352	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	378	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
368	} else {	394	} else {
369	die "open failed: $!\n";	395	die "open failed: $!\n";
370	}	396	}
371	};	397	};
372		398
		399	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		400	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		401	following POSIX and non-POSIX constants are available (missing ones on
		402	your system are, as usual, C<0>):
		403
		404	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		405	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		406	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
		407
373		408
374	=item aio_close $fh, $callback->($status)	409	=item aio_close $fh, $callback->($status)
375		410
376	Asynchronously close a file and call the callback with the result	411	Asynchronously close a file and call the callback with the result
377	code.	412	code.
…		…
386	Or in other words: the file descriptor will be closed, but it will not be	421	Or in other words: the file descriptor will be closed, but it will not be
387	free for reuse until the perl filehandle is closed.	422	free for reuse until the perl filehandle is closed.
388		423
389	=cut	424	=cut
390		425
		426	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		427
		428	Seeks the filehandle to the new C<$offset>, similarly to perl's
		429	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		430	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		431	C<IO::AIO::SEEK_END>).
		432
		433	The resulting absolute offset will be passed to the callback, or C<-1> in
		434	case of an error.
		435
		436	In theory, the C<$whence> constants could be different than the
		437	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		438	so don't panic.
		439
		440	As a GNU/Linux (and maybe Solaris) extension, also the constants
		441	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		442	could be found. No guarantees about suitability for use in C<aio_seek> or
		443	Perl's C<sysseek> can be made though, although I would naively assume they
		444	"just work".
		445
391	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	446	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
392		447
393	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	448	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
394		449
395	Reads or writes C<$length> bytes from or to the specified C<$fh> and	450	Reads or writes C<$length> bytes from or to the specified C<$fh> and
396	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	451	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
397	and calls the callback without the actual number of bytes read (or -1 on	452	calls the callback with the actual number of bytes transferred (or -1 on
398	error, just like the syscall).	453	error, just like the syscall).
399		454
400	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	455	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
401	offset plus the actual number of bytes read.	456	offset plus the actual number of bytes read.
402		457
…		…
427		482
428	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	483	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
429	reading at byte offset C<$in_offset>, and starts writing at the current	484	reading at byte offset C<$in_offset>, and starts writing at the current
430	file offset of C<$out_fh>. Because of that, it is not safe to issue more	485	file offset of C<$out_fh>. Because of that, it is not safe to issue more
431	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	486	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
432	other.	487	other. The same C<$in_fh> works fine though, as this function does not
		488	move or use the file offset of C<$in_fh>.
433		489
434	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than	490	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
435	are written, and there is no way to find out how many bytes have been read	491	are written, and there is no way to find out how many more bytes have been
436	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of	492	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
437	bytes written to C<$out_fh>. Only if the result value equals C<$length>	493	number of bytes written to C<$out_fh>. Only if the result value equals
438	one can assume that C<$length> bytes have been read.	494	C<$length> one can assume that C<$length> bytes have been read.
439		495
440	Unlike with other C<aio_> functions, it makes a lot of sense to use	496	Unlike with other C<aio_> functions, it makes a lot of sense to use
441	C<aio_sendfile> on non-blocking sockets, as long as one end (typically	497	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
442	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while	498	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
443	the socket I/O will be non-blocking. Note, however, that you can run into	499	the socket I/O will be non-blocking. Note, however, that you can run
444	a trap where C<aio_sendfile> reads some data with readahead, then fails	500	into a trap where C<aio_sendfile> reads some data with readahead, then
445	to write all data, and when the socket is ready the next time, the data	501	fails to write all data, and when the socket is ready the next time, the
446	in the cache is already lost, forcing C<aio_sendfile> to again hit the	502	data in the cache is already lost, forcing C<aio_sendfile> to again hit
447	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage	503	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
448	much better.	504	resource usage.
449		505
450	This call tries to make use of a native C<sendfile> syscall to provide	506	This call tries to make use of a native C<sendfile>-like syscall to
451	zero-copy operation. For this to work, C<$out_fh> should refer to a	507	provide zero-copy operation. For this to work, C<$out_fh> should refer to
452	socket, and C<$in_fh> should refer to an mmap'able file.	508	a socket, and C<$in_fh> should refer to an mmap'able file.
453		509
454	If a native sendfile cannot be found or it fails with C<ENOSYS>,	510	If a native sendfile cannot be found or it fails with C<ENOSYS>,
455	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	511	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
456	it will be emulated, so you can call C<aio_sendfile> on any type of	512	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
457	filehandle regardless of the limitations of the operating system.	513	type of filehandle regardless of the limitations of the operating system.
		514
		515	As native sendfile syscalls (as practically any non-POSIX interface hacked
		516	together in a hurry to improve benchmark numbers) tend to be rather buggy
		517	on many systems, this implementation tries to work around some known bugs
		518	in Linux and FreeBSD kernels (probably others, too), but that might fail,
		519	so you really really should check the return value of C<aio_sendfile> -
		520	fewer bytes than expected might have been transferred.
458		521
459		522
460	=item aio_readahead $fh,$offset,$length, $callback->($retval)	523	=item aio_readahead $fh,$offset,$length, $callback->($retval)
461		524
462	C<aio_readahead> populates the page cache with data from a file so that	525	C<aio_readahead> populates the page cache with data from a file so that
…		…
466	whole pages, so that offset is effectively rounded down to a page boundary	529	whole pages, so that offset is effectively rounded down to a page boundary
467	and bytes are read up to the next page boundary greater than or equal to	530	and bytes are read up to the next page boundary greater than or equal to
468	(off-set+length). C<aio_readahead> does not read beyond the end of the	531	(off-set+length). C<aio_readahead> does not read beyond the end of the
469	file. The current file offset of the file is left unchanged.	532	file. The current file offset of the file is left unchanged.
470		533
471	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	534	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
472	emulated by simply reading the data, which would have a similar effect.	535	be emulated by simply reading the data, which would have a similar effect.
473		536
474		537
475	=item aio_stat $fh_or_path, $callback->($status)	538	=item aio_stat $fh_or_path, $callback->($status)
476		539
477	=item aio_lstat $fh, $callback->($status)	540	=item aio_lstat $fh, $callback->($status)
…		…
546	namemax => 255,	609	namemax => 255,
547	frsize => 1024,	610	frsize => 1024,
548	fsid => 1810	611	fsid => 1810
549	}	612	}
550		613
		614	Here is a (likely partial - send me updates!) list of fsid values used by
		615	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		616
		617	0x0000adf5 adfs
		618	0x0000adff affs
		619	0x5346414f afs
		620	0x09041934 anon-inode filesystem
		621	0x00000187 autofs
		622	0x42465331 befs
		623	0x1badface bfs
		624	0x42494e4d binfmt_misc
		625	0x9123683e btrfs
		626	0x0027e0eb cgroupfs
		627	0xff534d42 cifs
		628	0x73757245 coda
		629	0x012ff7b7 coh
		630	0x28cd3d45 cramfs
		631	0x453dcd28 cramfs-wend (wrong endianness)
		632	0x64626720 debugfs
		633	0x00001373 devfs
		634	0x00001cd1 devpts
		635	0x0000f15f ecryptfs
		636	0x00414a53 efs
		637	0x0000137d ext
		638	0x0000ef53 ext2/ext3/ext4
		639	0x0000ef51 ext2
		640	0xf2f52010 f2fs
		641	0x00004006 fat
		642	0x65735546 fuseblk
		643	0x65735543 fusectl
		644	0x0bad1dea futexfs
		645	0x01161970 gfs2
		646	0x47504653 gpfs
		647	0x00004244 hfs
		648	0xf995e849 hpfs
		649	0x00c0ffee hostfs
		650	0x958458f6 hugetlbfs
		651	0x2bad1dea inotifyfs
		652	0x00009660 isofs
		653	0x000072b6 jffs2
		654	0x3153464a jfs
		655	0x6b414653 k-afs
		656	0x0bd00bd0 lustre
		657	0x0000137f minix
		658	0x0000138f minix 30 char names
		659	0x00002468 minix v2
		660	0x00002478 minix v2 30 char names
		661	0x00004d5a minix v3
		662	0x19800202 mqueue
		663	0x00004d44 msdos
		664	0x0000564c novell
		665	0x00006969 nfs
		666	0x6e667364 nfsd
		667	0x00003434 nilfs
		668	0x5346544e ntfs
		669	0x00009fa1 openprom
		670	0x7461636F ocfs2
		671	0x00009fa0 proc
		672	0x6165676c pstorefs
		673	0x0000002f qnx4
		674	0x68191122 qnx6
		675	0x858458f6 ramfs
		676	0x52654973 reiserfs
		677	0x00007275 romfs
		678	0x67596969 rpc_pipefs
		679	0x73636673 securityfs
		680	0xf97cff8c selinux
		681	0x0000517b smb
		682	0x534f434b sockfs
		683	0x73717368 squashfs
		684	0x62656572 sysfs
		685	0x012ff7b6 sysv2
		686	0x012ff7b5 sysv4
		687	0x01021994 tmpfs
		688	0x15013346 udf
		689	0x00011954 ufs
		690	0x54190100 ufs byteswapped
		691	0x00009fa2 usbdevfs
		692	0x01021997 v9fs
		693	0xa501fcf5 vxfs
		694	0xabba1974 xenfs
		695	0x012ff7b4 xenix
		696	0x58465342 xfs
		697	0x012fd16d xia
551		698
552	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	699	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
553		700
554	Works like perl's C<utime> function (including the special case of $atime	701	Works like perl's C<utime> function (including the special case of $atime
555	and $mtime being undef). Fractional times are supported if the underlying	702	and $mtime being undef). Fractional times are supported if the underlying
…		…
583	=item aio_truncate $fh_or_path, $offset, $callback->($status)	730	=item aio_truncate $fh_or_path, $offset, $callback->($status)
584		731
585	Works like truncate(2) or ftruncate(2).	732	Works like truncate(2) or ftruncate(2).
586		733
587		734
		735	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		736
		737	Allocates or frees disk space according to the C<$mode> argument. See the
		738	linux C<fallocate> documentation for details.
		739
		740	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		741	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		742	to deallocate a file range.
		743
		744	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		745	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		746	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		747	to unshare shared blocks (see your L<fallocate(2)> manpage).
		748
		749	The file system block size used by C<fallocate> is presumably the
		750	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		751	can dictate other limitations.
		752
		753	If C<fallocate> isn't available or cannot be emulated (currently no
		754	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		755
		756
588	=item aio_chmod $fh_or_path, $mode, $callback->($status)	757	=item aio_chmod $fh_or_path, $mode, $callback->($status)
589		758
590	Works like perl's C<chmod> function.	759	Works like perl's C<chmod> function.
591		760
592		761
…		…
594		763
595	Asynchronously unlink (delete) a file and call the callback with the	764	Asynchronously unlink (delete) a file and call the callback with the
596	result code.	765	result code.
597		766
598		767
599	=item aio_mknod $path, $mode, $dev, $callback->($status)	768	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
600		769
601	[EXPERIMENTAL]	770	[EXPERIMENTAL]
602		771
603	Asynchronously create a device node (or fifo). See mknod(2).	772	Asynchronously create a device node (or fifo). See mknod(2).
604		773
605	The only (POSIX-) portable way of calling this function is:	774	The only (POSIX-) portable way of calling this function is:
606		775
607	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	776	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
608		777
609	See C<aio_stat> for info about some potentially helpful extra constants	778	See C<aio_stat> for info about some potentially helpful extra constants
610	and functions.	779	and functions.
611		780
612	=item aio_link $srcpath, $dstpath, $callback->($status)	781	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
619		788
620	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	789	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
621	the path C<$dstpath> and call the callback with the result code.	790	the path C<$dstpath> and call the callback with the result code.
622		791
623		792
624	=item aio_readlink $path, $callback->($link)	793	=item aio_readlink $pathname, $callback->($link)
625		794
626	Asynchronously read the symlink specified by C<$path> and pass it to	795	Asynchronously read the symlink specified by C<$path> and pass it to
627	the callback. If an error occurs, nothing or undef gets passed to the	796	the callback. If an error occurs, nothing or undef gets passed to the
628	callback.	797	callback.
629		798
630		799
		800	=item aio_realpath $pathname, $callback->($path)
		801
		802	Asynchronously make the path absolute and resolve any symlinks in
		803	C<$path>. The resulting path only consists of directories (same as
		804	L<Cwd::realpath>).
		805
		806	This request can be used to get the absolute path of the current working
		807	directory by passing it a path of F<.> (a single dot).
		808
		809
631	=item aio_rename $srcpath, $dstpath, $callback->($status)	810	=item aio_rename $srcpath, $dstpath, $callback->($status)
632		811
633	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	812	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
634	rename(2) and call the callback with the result code.	813	rename(2) and call the callback with the result code.
		814
		815	On systems that support the AIO::WD working directory abstraction
		816	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		817	of failing, C<rename> is called on the absolute path of C<$wd>.
		818
		819
		820	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		821
		822	Basically a version of C<aio_rename> with an additional C<$flags>
		823	argument. Calling this with C<$flags=0> is the same as calling
		824	C<aio_rename>.
		825
		826	Non-zero flags are currently only supported on GNU/Linux systems that
		827	support renameat2. Other systems fail with C<ENOSYS> in this case.
		828
		829	The following constants are available (missing ones are, as usual C<0>),
		830	see renameat2(2) for details:
		831
		832	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		833	and C<IO::AIO::RENAME_WHITEOUT>.
635		834
636		835
637	=item aio_mkdir $pathname, $mode, $callback->($status)	836	=item aio_mkdir $pathname, $mode, $callback->($status)
638		837
639	Asynchronously mkdir (create) a directory and call the callback with	838	Asynchronously mkdir (create) a directory and call the callback with
…		…
644	=item aio_rmdir $pathname, $callback->($status)	843	=item aio_rmdir $pathname, $callback->($status)
645		844
646	Asynchronously rmdir (delete) a directory and call the callback with the	845	Asynchronously rmdir (delete) a directory and call the callback with the
647	result code.	846	result code.
648		847
		848	On systems that support the AIO::WD working directory abstraction
		849	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		850	C<rmdir> is called on the absolute path of C<$wd>.
		851
649		852
650	=item aio_readdir $pathname, $callback->($entries)	853	=item aio_readdir $pathname, $callback->($entries)
651		854
652	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	855	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
653	directory (i.e. opendir + readdir + closedir). The entries will not be	856	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
657	array-ref with the filenames.	860	array-ref with the filenames.
658		861
659		862
660	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	863	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
661		864
662	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	865	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
663	behaviour and output format. In case of an error, C<$entries> will be	866	tune behaviour and output format. In case of an error, C<$entries> will be
664	C<undef>.	867	C<undef>.
665		868
666	The flags are a combination of the following constants, ORed together (the	869	The flags are a combination of the following constants, ORed together (the
667	flags will also be passed to the callback, possibly modified):	870	flags will also be passed to the callback, possibly modified):
668		871
…		…
715		918
716	=item IO::AIO::READDIR_FOUND_UNKNOWN	919	=item IO::AIO::READDIR_FOUND_UNKNOWN
717		920
718	This flag should not be set when calling C<aio_readdirx>. Instead, it	921	This flag should not be set when calling C<aio_readdirx>. Instead, it
719	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	922	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
720	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	923	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
721	C<$type>'s are known, which can be used to speed up some algorithms.	924	C<$type>'s are known, which can be used to speed up some algorithms.
722		925
723	=back	926	=back
724		927
725		928
726	=item aio_load $path, $data, $callback->($status)	929	=item aio_load $pathname, $data, $callback->($status)
727		930
728	This is a composite request that tries to fully load the given file into	931	This is a composite request that tries to fully load the given file into
729	memory. Status is the same as with aio_read.	932	memory. Status is the same as with aio_read.
730		933
731	=cut	934	=cut
…		…
853	if ($_[0] && $! == EXDEV) {	1056	if ($_[0] && $! == EXDEV) {
854	aioreq_pri $pri;	1057	aioreq_pri $pri;
855	add $grp aio_copy $src, $dst, sub {	1058	add $grp aio_copy $src, $dst, sub {
856	$grp->result ($_[0]);	1059	$grp->result ($_[0]);
857		1060
858	if (!$_[0]) {	1061	unless ($_[0]) {
859	aioreq_pri $pri;	1062	aioreq_pri $pri;
860	add $grp aio_unlink $src;	1063	add $grp aio_unlink $src;
861	}	1064	}
862	};	1065	};
863	} else {	1066	} else {
…		…
866	};	1069	};
867		1070
868	$grp	1071	$grp
869	}	1072	}
870		1073
871	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1074	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
872		1075
873	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1076	Scans a directory (similar to C<aio_readdir>) but additionally tries to
874	efficiently separate the entries of directory C<$path> into two sets of	1077	efficiently separate the entries of directory C<$path> into two sets of
875	names, directories you can recurse into (directories), and ones you cannot	1078	names, directories you can recurse into (directories), and ones you cannot
876	recurse into (everything else, including symlinks to directories).	1079	recurse into (everything else, including symlinks to directories).
…		…
907	Then entries will be sorted into likely directories a non-initial dot	1110	Then entries will be sorted into likely directories a non-initial dot
908	currently) and likely non-directories (see C<aio_readdirx>). Then every	1111	currently) and likely non-directories (see C<aio_readdirx>). Then every
909	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1112	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
910	in order of their inode numbers. If that succeeds, it assumes that the	1113	in order of their inode numbers. If that succeeds, it assumes that the
911	entry is a directory or a symlink to directory (which will be checked	1114	entry is a directory or a symlink to directory (which will be checked
912	seperately). This is often faster than stat'ing the entry itself because	1115	separately). This is often faster than stat'ing the entry itself because
913	filesystems might detect the type of the entry without reading the inode	1116	filesystems might detect the type of the entry without reading the inode
914	data (e.g. ext2fs filetype feature), even on systems that cannot return	1117	data (e.g. ext2fs filetype feature), even on systems that cannot return
915	the filetype information on readdir.	1118	the filetype information on readdir.
916		1119
917	If the known number of directories (link count - 2) has been reached, the	1120	If the known number of directories (link count - 2) has been reached, the
…		…
933		1136
934	my $grp = aio_group $cb;	1137	my $grp = aio_group $cb;
935		1138
936	$maxreq = 4 if $maxreq <= 0;	1139	$maxreq = 4 if $maxreq <= 0;
937		1140
938	# stat once	1141	# get a wd object
939	aioreq_pri $pri;	1142	aioreq_pri $pri;
940	add $grp aio_stat $path, sub {	1143	add $grp aio_wd $path, sub {
		1144	$_[0]
941	return $grp->result () if $_[0];	1145	or return $grp->result ();
942	my $now = time;
943	my $hash1 = join ":", (stat _)[0,1,3,7,9];
944		1146
945	# read the directory entries	1147	my $wd = [shift, "."];
		1148
		1149	# stat once
946	aioreq_pri $pri;	1150	aioreq_pri $pri;
947	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1151	add $grp aio_stat $wd, sub {
948	my $entries = shift
949	or return $grp->result ();	1152	return $grp->result () if $_[0];
		1153	my $now = time;
		1154	my $hash1 = join ":", (stat _)[0,1,3,7,9];
950		1155
951	# stat the dir another time	1156	# read the directory entries
952	aioreq_pri $pri;	1157	aioreq_pri $pri;
		1158	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1159	my $entries = shift
		1160	or return $grp->result ();
		1161
		1162	# stat the dir another time
		1163	aioreq_pri $pri;
953	add $grp aio_stat $path, sub {	1164	add $grp aio_stat $wd, sub {
954	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1165	my $hash2 = join ":", (stat _)[0,1,3,7,9];
955		1166
956	my $ndirs;	1167	my $ndirs;
957		1168
958	# take the slow route if anything looks fishy	1169	# take the slow route if anything looks fishy
959	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1170	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
960	$ndirs = -1;	1171	$ndirs = -1;
961	} else {	1172	} else {
962	# if nlink == 2, we are finished	1173	# if nlink == 2, we are finished
963	# for non-posix-fs's, we rely on nlink < 2	1174	# for non-posix-fs's, we rely on nlink < 2
964	$ndirs = (stat _)[3] - 2	1175	$ndirs = (stat _)[3] - 2
965	or return $grp->result ([], $entries);	1176	or return $grp->result ([], $entries);
966	}	1177	}
967		1178
968	my (@dirs, @nondirs);	1179	my (@dirs, @nondirs);
969		1180
970	my $statgrp = add $grp aio_group sub {	1181	my $statgrp = add $grp aio_group sub {
971	$grp->result (\@dirs, \@nondirs);	1182	$grp->result (\@dirs, \@nondirs);
972	};	1183	};
973		1184
974	limit $statgrp $maxreq;	1185	limit $statgrp $maxreq;
975	feed $statgrp sub {	1186	feed $statgrp sub {
976	return unless @$entries;	1187	return unless @$entries;
977	my $entry = shift @$entries;	1188	my $entry = shift @$entries;
978		1189
979	aioreq_pri $pri;	1190	aioreq_pri $pri;
		1191	$wd->[1] = "$entry/.";
980	add $statgrp aio_stat "$path/$entry/.", sub {	1192	add $statgrp aio_stat $wd, sub {
981	if ($_[0] < 0) {	1193	if ($_[0] < 0) {
982	push @nondirs, $entry;	1194	push @nondirs, $entry;
983	} else {	1195	} else {
984	# need to check for real directory	1196	# need to check for real directory
985	aioreq_pri $pri;	1197	aioreq_pri $pri;
		1198	$wd->[1] = $entry;
986	add $statgrp aio_lstat "$path/$entry", sub {	1199	add $statgrp aio_lstat $wd, sub {
987	if (-d _) {	1200	if (-d _) {
988	push @dirs, $entry;	1201	push @dirs, $entry;
989		1202
990	unless (--$ndirs) {	1203	unless (--$ndirs) {
991	push @nondirs, @$entries;	1204	push @nondirs, @$entries;
992	feed $statgrp;	1205	feed $statgrp;
		1206	}
		1207	} else {
		1208	push @nondirs, $entry;
993	}	1209	}
994	} else {
995	push @nondirs, $entry;
996	}	1210	}
997	}	1211	}
998	}	1212	};
999	};	1213	};
1000	};	1214	};
1001	};	1215	};
1002	};	1216	};
1003	};	1217	};
1004		1218
1005	$grp	1219	$grp
1006	}	1220	}
1007		1221
1008	=item aio_rmtree $path, $callback->($status)	1222	=item aio_rmtree $pathname, $callback->($status)
1009		1223
1010	Delete a directory tree starting (and including) C<$path>, return the	1224	Delete a directory tree starting (and including) C<$path>, return the
1011	status of the final C<rmdir> only. This is a composite request that	1225	status of the final C<rmdir> only. This is a composite request that
1012	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1226	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1013	everything else.	1227	everything else.
1014		1228
1015	=cut	1229	=cut
1016		1230
…		…
1038	};	1252	};
1039		1253
1040	$grp	1254	$grp
1041	}	1255	}
1042		1256
		1257	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1258
		1259	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1260
		1261	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1262	they execute asynchronously and pass the return value to the callback.
		1263
		1264	Both calls can be used for a lot of things, some of which make more sense
		1265	to run asynchronously in their own thread, while some others make less
		1266	sense. For example, calls that block waiting for external events, such
		1267	as locking, will also lock down an I/O thread while it is waiting, which
		1268	can deadlock the whole I/O system. At the same time, there might be no
		1269	alternative to using a thread to wait.
		1270
		1271	So in general, you should only use these calls for things that do
		1272	(filesystem) I/O, not for things that wait for other events (network,
		1273	other processes), although if you are careful and know what you are doing,
		1274	you still can.
		1275
		1276	The following constants are available (missing ones are, as usual C<0>):
		1277
		1278	C<F_DUPFD_CLOEXEC>,
		1279
		1280	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1281
		1282	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1283
		1284	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1285	C<FS_IOC_FIEMAP>.
		1286
		1287	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1288	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1289
		1290	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1291	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1292	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1293	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1294	C<FS_FL_USER_MODIFIABLE>.
		1295
		1296	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1297	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1298	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1299	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
		1300
1043	=item aio_sync $callback->($status)	1301	=item aio_sync $callback->($status)
1044		1302
1045	Asynchronously call sync and call the callback when finished.	1303	Asynchronously call sync and call the callback when finished.
1046		1304
1047	=item aio_fsync $fh, $callback->($status)	1305	=item aio_fsync $fh, $callback->($status)
…		…
1054	Asynchronously call fdatasync on the given filehandle and call the	1312	Asynchronously call fdatasync on the given filehandle and call the
1055	callback with the fdatasync result code.	1313	callback with the fdatasync result code.
1056		1314
1057	If this call isn't available because your OS lacks it or it couldn't be	1315	If this call isn't available because your OS lacks it or it couldn't be
1058	detected, it will be emulated by calling C<fsync> instead.	1316	detected, it will be emulated by calling C<fsync> instead.
		1317
		1318	=item aio_syncfs $fh, $callback->($status)
		1319
		1320	Asynchronously call the syncfs syscall to sync the filesystem associated
		1321	to the given filehandle and call the callback with the syncfs result
		1322	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1323	errno to C<ENOSYS> nevertheless.
1059		1324
1060	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1325	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1061		1326
1062	Sync the data portion of the file specified by C<$offset> and C<$length>	1327	Sync the data portion of the file specified by C<$offset> and C<$length>
1063	to disk (but NOT the metadata), by calling the Linux-specific	1328	to disk (but NOT the metadata), by calling the Linux-specific
…		…
1067	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1332	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1068	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1333	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1069	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1334	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1070	manpage for details.	1335	manpage for details.
1071		1336
1072	=item aio_pathsync $path, $callback->($status)	1337	=item aio_pathsync $pathname, $callback->($status)
1073		1338
1074	This request tries to open, fsync and close the given path. This is a	1339	This request tries to open, fsync and close the given path. This is a
1075	composite request intended to sync directories after directory operations	1340	composite request intended to sync directories after directory operations
1076	(E.g. rename). This might not work on all operating systems or have any	1341	(E.g. rename). This might not work on all operating systems or have any
1077	specific effect, but usually it makes sure that directory changes get	1342	specific effect, but usually it makes sure that directory changes get
…		…
1108	};	1373	};
1109		1374
1110	$grp	1375	$grp
1111	}	1376	}
1112		1377
1113	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1378	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1114		1379
1115	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1380	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1116	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1381	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1117	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1382	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1118	scalar must only be modified in-place while an aio operation is pending on	1383	scalar must only be modified in-place while an aio operation is pending on
…		…
1120		1385
1121	It calls the C<msync> function of your OS, if available, with the memory	1386	It calls the C<msync> function of your OS, if available, with the memory
1122	area starting at C<$offset> in the string and ending C<$length> bytes	1387	area starting at C<$offset> in the string and ending C<$length> bytes
1123	later. If C<$length> is negative, counts from the end, and if C<$length>	1388	later. If C<$length> is negative, counts from the end, and if C<$length>
1124	is C<undef>, then it goes till the end of the string. The flags can be	1389	is C<undef>, then it goes till the end of the string. The flags can be
1125	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1390	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1126	C<IO::AIO::MS_SYNC>.	1391	C<IO::AIO::MS_INVALIDATE>.
1127		1392
1128	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1393	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1129		1394
1130	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1395	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1131	scalars.	1396	scalars.
1132		1397
1133	It touches (reads or writes) all memory pages in the specified	1398	It touches (reads or writes) all memory pages in the specified
1134	range inside the scalar. All caveats and parameters are the same	1399	range inside the scalar. All caveats and parameters are the same
1135	as for C<aio_msync>, above, except for flags, which must be either	1400	as for C<aio_msync>, above, except for flags, which must be either
1136	C<0> (which reads all pages and ensures they are instantiated) or	1401	C<0> (which reads all pages and ensures they are instantiated) or
1137	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1402	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1138	writing an octet from it, which dirties the page).	1403	writing an octet from it, which dirties the page).
1139		1404
1140	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1405	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1141		1406
1142	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1407	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1173	documented under L<MISCELLANEOUS FUNCTIONS>.	1438	documented under L<MISCELLANEOUS FUNCTIONS>.
1174		1439
1175	Example: asynchronously lock all current and future pages into memory.	1440	Example: asynchronously lock all current and future pages into memory.
1176		1441
1177	aio_mlockall IO::AIO::MCL_FUTURE;	1442	aio_mlockall IO::AIO::MCL_FUTURE;
		1443
		1444	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1445
		1446	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1447	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1448	the ioctl is not available on your OS, then this request will fail with
		1449	C<ENOSYS>.
		1450
		1451	C<$start> is the starting offset to query extents for, C<$length> is the
		1452	size of the range to query - if it is C<undef>, then the whole file will
		1453	be queried.
		1454
		1455	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1456	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1457	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1458	the data portion.
		1459
		1460	C<$count> is the maximum number of extent records to return. If it is
		1461	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1462	case, if it is C<0>, then the callback receives the number of extents
		1463	instead of the extents themselves (which is unreliable, see below).
		1464
		1465	If an error occurs, the callback receives no arguments. The special
		1466	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1467
		1468	Otherwise, the callback receives an array reference with extent
		1469	structures. Each extent structure is an array reference itself, with the
		1470	following members:
		1471
		1472	[$logical, $physical, $length, $flags]
		1473
		1474	Flags is any combination of the following flag values (typically either C<0>
		1475	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1476
		1477	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1478	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1479	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1480	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1481	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1482	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1483
		1484	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1485	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1486	it to return all extents of a range for files with large number of
		1487	extents. The code works around all these issues if C<$count> is undef.
1178		1488
1179	=item aio_group $callback->(...)	1489	=item aio_group $callback->(...)
1180		1490
1181	This is a very special aio request: Instead of doing something, it is a	1491	This is a very special aio request: Instead of doing something, it is a
1182	container for other aio requests, which is useful if you want to bundle	1492	container for other aio requests, which is useful if you want to bundle
…		…
1219	like sleep and file handle readable/writable, the overhead this creates is	1529	like sleep and file handle readable/writable, the overhead this creates is
1220	immense (it blocks a thread for a long time) so do not use this function	1530	immense (it blocks a thread for a long time) so do not use this function
1221	except to put your application under artificial I/O pressure.	1531	except to put your application under artificial I/O pressure.
1222		1532
1223	=back	1533	=back
		1534
		1535
		1536	=head2 IO::AIO::WD - multiple working directories
		1537
		1538	Your process only has one current working directory, which is used by all
		1539	threads. This makes it hard to use relative paths (some other component
		1540	could call C<chdir> at any time, and it is hard to control when the path
		1541	will be used by IO::AIO).
		1542
		1543	One solution for this is to always use absolute paths. This usually works,
		1544	but can be quite slow (the kernel has to walk the whole path on every
		1545	access), and can also be a hassle to implement.
		1546
		1547	Newer POSIX systems have a number of functions (openat, fdopendir,
		1548	futimensat and so on) that make it possible to specify working directories
		1549	per operation.
		1550
		1551	For portability, and because the clowns who "designed", or shall I write,
		1552	perpetrated this new interface were obviously half-drunk, this abstraction
		1553	cannot be perfect, though.
		1554
		1555	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1556	object. This object stores the canonicalised, absolute version of the
		1557	path, and on systems that allow it, also a directory file descriptor.
		1558
		1559	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1560	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1561	object and a pathname instead (or the IO::AIO::WD object alone, which
		1562	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1563	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1564	to that IO::AIO::WD object.
		1565
		1566	For example, to get a wd object for F</etc> and then stat F<passwd>
		1567	inside, you would write:
		1568
		1569	aio_wd "/etc", sub {
		1570	my $etcdir = shift;
		1571
		1572	# although $etcdir can be undef on error, there is generally no reason
		1573	# to check for errors here, as aio_stat will fail with ENOENT
		1574	# when $etcdir is undef.
		1575
		1576	aio_stat [$etcdir, "passwd"], sub {
		1577	# yay
		1578	};
		1579	};
		1580
		1581	The fact that C<aio_wd> is a request and not a normal function shows that
		1582	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1583	which is why it is done asynchronously.
		1584
		1585	To stat the directory obtained with C<aio_wd> above, one could write
		1586	either of the following three request calls:
		1587
		1588	aio_lstat "/etc" , sub { ... # pathname as normal string
		1589	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1590	aio_lstat $wd , sub { ... # shorthand for the previous
		1591
		1592	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1593	object and the pathname string, so you could write the following without
		1594	causing any issues due to C<$path> getting reused:
		1595
		1596	my $path = [$wd, undef];
		1597
		1598	for my $name (qw(abc def ghi)) {
		1599	$path->[1] = $name;
		1600	aio_stat $path, sub {
		1601	# ...
		1602	};
		1603	}
		1604
		1605	There are some caveats: when directories get renamed (or deleted), the
		1606	pathname string doesn't change, so will point to the new directory (or
		1607	nowhere at all), while the directory fd, if available on the system,
		1608	will still point to the original directory. Most functions accepting a
		1609	pathname will use the directory fd on newer systems, and the string on
		1610	older systems. Some functions (such as realpath) will always rely on the
		1611	string form of the pathname.
		1612
		1613	So this functionality is mainly useful to get some protection against
		1614	C<chdir>, to easily get an absolute path out of a relative path for future
		1615	reference, and to speed up doing many operations in the same directory
		1616	(e.g. when stat'ing all files in a directory).
		1617
		1618	The following functions implement this working directory abstraction:
		1619
		1620	=over 4
		1621
		1622	=item aio_wd $pathname, $callback->($wd)
		1623
		1624	Asynchonously canonicalise the given pathname and convert it to an
		1625	IO::AIO::WD object representing it. If possible and supported on the
		1626	system, also open a directory fd to speed up pathname resolution relative
		1627	to this working directory.
		1628
		1629	If something goes wrong, then C<undef> is passwd to the callback instead
		1630	of a working directory object and C<$!> is set appropriately. Since
		1631	passing C<undef> as working directory component of a pathname fails the
		1632	request with C<ENOENT>, there is often no need for error checking in the
		1633	C<aio_wd> callback, as future requests using the value will fail in the
		1634	expected way.
		1635
		1636	=item IO::AIO::CWD
		1637
		1638	This is a compiletime constant (object) that represents the process
		1639	current working directory.
		1640
		1641	Specifying this object as working directory object for a pathname is as if
		1642	the pathname would be specified directly, without a directory object. For
		1643	example, these calls are functionally identical:
		1644
		1645	aio_stat "somefile", sub { ... };
		1646	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1647
		1648	=back
		1649
		1650	To recover the path associated with an IO::AIO::WD object, you can use
		1651	C<aio_realpath>:
		1652
		1653	aio_realpath $wd, sub {
		1654	warn "path is $_[0]\n";
		1655	};
		1656
		1657	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1658	sometimes, fall back to using an absolue path.
1224		1659
1225	=head2 IO::AIO::REQ CLASS	1660	=head2 IO::AIO::REQ CLASS
1226		1661
1227	All non-aggregate C<aio_*> functions return an object of this class when	1662	All non-aggregate C<aio_*> functions return an object of this class when
1228	called in non-void context.	1663	called in non-void context.
…		…
1346		1781
1347	Sets a feeder/generator on this group: every group can have an attached	1782	Sets a feeder/generator on this group: every group can have an attached
1348	generator that generates requests if idle. The idea behind this is that,	1783	generator that generates requests if idle. The idea behind this is that,
1349	although you could just queue as many requests as you want in a group,	1784	although you could just queue as many requests as you want in a group,
1350	this might starve other requests for a potentially long time. For example,	1785	this might starve other requests for a potentially long time. For example,
1351	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1786	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1352	delaying any later requests for a long time.	1787	requests, delaying any later requests for a long time.
1353		1788
1354	To avoid this, and allow incremental generation of requests, you can	1789	To avoid this, and allow incremental generation of requests, you can
1355	instead a group and set a feeder on it that generates those requests. The	1790	instead a group and set a feeder on it that generates those requests. The
1356	feed callback will be called whenever there are few enough (see C<limit>,	1791	feed callback will be called whenever there are few enough (see C<limit>,
1357	below) requests active in the group itself and is expected to queue more	1792	below) requests active in the group itself and is expected to queue more
…		…
1406		1841
1407	See C<poll_cb> for an example.	1842	See C<poll_cb> for an example.
1408		1843
1409	=item IO::AIO::poll_cb	1844	=item IO::AIO::poll_cb
1410		1845
1411	Process some outstanding events on the result pipe. You have to call	1846	Process some requests that have reached the result phase (i.e. they have
		1847	been executed but the results are not yet reported). You have to call
		1848	this "regularly" to finish outstanding requests.
		1849
1412	this regularly. Returns C<0> if all events could be processed (or there	1850	Returns C<0> if all events could be processed (or there were no
1413	were no events to process), or C<-1> if it returned earlier for whatever	1851	events to process), or C<-1> if it returned earlier for whatever
1414	reason. Returns immediately when no events are outstanding. The amount of	1852	reason. Returns immediately when no events are outstanding. The amount
1415	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1853	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1416	C<IO::AIO::max_poll_time>.	1854	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1417		1855
1418	If not all requests were processed for whatever reason, the filehandle	1856	If not all requests were processed for whatever reason, the poll file
1419	will still be ready when C<poll_cb> returns, so normally you don't have to	1857	descriptor will still be ready when C<poll_cb> returns, so normally you
1420	do anything special to have it called later.	1858	don't have to do anything special to have it called later.
1421		1859
1422	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1860	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1423	ready, it can be beneficial to call this function from loops which submit	1861	ready, it can be beneficial to call this function from loops which submit
1424	a lot of requests, to make sure the results get processed when they become	1862	a lot of requests, to make sure the results get processed when they become
1425	available and not just when the loop is finished and the event loop takes	1863	available and not just when the loop is finished and the event loop takes
…		…
1434	poll => 'r', async => 1,	1872	poll => 'r', async => 1,
1435	cb => \&IO::AIO::poll_cb);	1873	cb => \&IO::AIO::poll_cb);
1436		1874
1437	=item IO::AIO::poll_wait	1875	=item IO::AIO::poll_wait
1438		1876
1439	If there are any outstanding requests and none of them in the result	1877	Wait until either at least one request is in the result phase or no
1440	phase, wait till the result filehandle becomes ready for reading (simply	1878	requests are outstanding anymore.
1441	does a C<select> on the filehandle. This is useful if you want to	1879
1442	synchronously wait for some requests to finish).	1880	This is useful if you want to synchronously wait for some requests to
		1881	become ready, without actually handling them.
1443		1882
1444	See C<nreqs> for an example.	1883	See C<nreqs> for an example.
1445		1884
1446	=item IO::AIO::poll	1885	=item IO::AIO::poll
1447		1886
…		…
1555	Sets the minimum idle timeout (default 10) after which worker threads are	1994	Sets the minimum idle timeout (default 10) after which worker threads are
1556	allowed to exit. SEe C<IO::AIO::max_idle>.	1995	allowed to exit. SEe C<IO::AIO::max_idle>.
1557		1996
1558	=item IO::AIO::max_outstanding $maxreqs	1997	=item IO::AIO::max_outstanding $maxreqs
1559		1998
		1999	Sets the maximum number of outstanding requests to C<$nreqs>. If
		2000	you do queue up more than this number of requests, the next call to
		2001	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		2002	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		2003	longer exceeded.
		2004
		2005	In other words, this setting does not enforce a queue limit, but can be
		2006	used to make poll functions block if the limit is exceeded.
		2007
1560	This is a very bad function to use in interactive programs because it	2008	This is a very bad function to use in interactive programs because it
1561	blocks, and a bad way to reduce concurrency because it is inexact: Better	2009	blocks, and a bad way to reduce concurrency because it is inexact: Better
1562	use an C<aio_group> together with a feed callback.	2010	use an C<aio_group> together with a feed callback.
1563		2011
1564	Sets the maximum number of outstanding requests to C<$nreqs>. If you	2012	Its main use is in scripts without an event loop - when you want to stat
1565	do queue up more than this number of requests, the next call to the	2013	a lot of files, you can write somehting like this:
1566	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1567	function will block until the limit is no longer exceeded.
1568		2014
1569	The default value is very large, so there is no practical limit on the	2015	IO::AIO::max_outstanding 32;
1570	number of outstanding requests.
1571		2016
1572	You can still queue as many requests as you want. Therefore,	2017	for my $path (...) {
1573	C<max_outstanding> is mainly useful in simple scripts (with low values) or	2018	aio_stat $path , ...;
1574	as a stop gap to shield against fatal memory overflow (with large values).	2019	IO::AIO::poll_cb;
		2020	}
		2021
		2022	IO::AIO::flush;
		2023
		2024	The call to C<poll_cb> inside the loop will normally return instantly, but
		2025	as soon as more thna C<32> reqeusts are in-flight, it will block until
		2026	some requests have been handled. This keeps the loop from pushing a large
		2027	number of C<aio_stat> requests onto the queue.
		2028
		2029	The default value for C<max_outstanding> is very large, so there is no
		2030	practical limit on the number of outstanding requests.
1575		2031
1576	=back	2032	=back
1577		2033
1578	=head3 STATISTICAL INFORMATION	2034	=head3 STATISTICAL INFORMATION
1579		2035
…		…
1601		2057
1602	=back	2058	=back
1603		2059
1604	=head3 MISCELLANEOUS FUNCTIONS	2060	=head3 MISCELLANEOUS FUNCTIONS
1605		2061
1606	IO::AIO implements some functions that might be useful, but are not	2062	IO::AIO implements some functions that are useful when you want to use
1607	asynchronous.	2063	some "Advanced I/O" function not available to in Perl, without going the
		2064	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2065	counterpart.
1608		2066
1609	=over 4	2067	=over 4
1610		2068
1611	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2069	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1612		2070
…		…
1619		2077
1620	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2078	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1621		2079
1622	Simply calls the C<posix_fadvise> function (see its	2080	Simply calls the C<posix_fadvise> function (see its
1623	manpage for details). The following advice constants are	2081	manpage for details). The following advice constants are
1624	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2082	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1625	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2083	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1626	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2084	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1627		2085
1628	On systems that do not implement C<posix_fadvise>, this function returns	2086	On systems that do not implement C<posix_fadvise>, this function returns
1629	ENOSYS, otherwise the return value of C<posix_fadvise>.	2087	ENOSYS, otherwise the return value of C<posix_fadvise>.
1630		2088
1631	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2089	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1632		2090
1633	Simply calls the C<posix_madvise> function (see its	2091	Simply calls the C<posix_madvise> function (see its
1634	manpage for details). The following advice constants are	2092	manpage for details). The following advice constants are
1635	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2093	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1636	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2094	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2095	C<IO::AIO::MADV_DONTNEED>.
		2096
		2097	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2098	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2099	will be reduced to fit into the C<$scalar>.
1637		2100
1638	On systems that do not implement C<posix_madvise>, this function returns	2101	On systems that do not implement C<posix_madvise>, this function returns
1639	ENOSYS, otherwise the return value of C<posix_madvise>.	2102	ENOSYS, otherwise the return value of C<posix_madvise>.
1640		2103
1641	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2104	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1642		2105
1643	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2106	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1644	$scalar (see its manpage for details). The following protect	2107	$scalar (see its manpage for details). The following protect
1645	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2108	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1646	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2109	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		2110
		2111	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2112	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2113	will be reduced to fit into the C<$scalar>.
1647		2114
1648	On systems that do not implement C<mprotect>, this function returns	2115	On systems that do not implement C<mprotect>, this function returns
1649	ENOSYS, otherwise the return value of C<mprotect>.	2116	ENOSYS, otherwise the return value of C<mprotect>.
1650		2117
1651	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2118	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1652		2119
1653	Memory-maps a file (or anonymous memory range) and attaches it to the	2120	Memory-maps a file (or anonymous memory range) and attaches it to the
1654	given C<$scalar>, which will act like a string scalar.	2121	given C<$scalar>, which will act like a string scalar. Returns true on
		2122	success, and false otherwise.
1655		2123
		2124	The scalar must exist, but its contents do not matter - this means you
		2125	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2126	the scalar first.
		2127
1656	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2128	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1657	change the string length, and most read-only operations such as copying it	2129	which don't change the string length, and most read-only operations such
1658	or searching it with regexes and so on.	2130	as copying it or searching it with regexes and so on.
1659		2131
1660	Anything else is unsafe and will, at best, result in memory leaks.	2132	Anything else is unsafe and will, at best, result in memory leaks.
1661		2133
1662	The memory map associated with the C<$scalar> is automatically removed	2134	The memory map associated with the C<$scalar> is automatically removed
1663	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2135	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1664	C<IO::AIO::munmap> functions are called.	2136	or C<IO::AIO::munmap> functions are called on it.
1665		2137
1666	This calls the C<mmap>(2) function internally. See your system's manual	2138	This calls the C<mmap>(2) function internally. See your system's manual
1667	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2139	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1668		2140
1669	The C<$length> must be larger than zero and smaller than the actual	2141	The C<$length> must be larger than zero and smaller than the actual
1670	filesize.	2142	filesize.
1671		2143
1672	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2144	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1673	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2145	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1674		2146
1675	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2147	C<$flags> can be a combination of
1676	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2148	C<IO::AIO::MAP_SHARED> or
1677	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2149	C<IO::AIO::MAP_PRIVATE>,
		2150	or a number of system-specific flags (when not available, the are C<0>):
1678	(which is set to C<MAP_ANON> if your system only provides this	2151	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1679	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2152	C<IO::AIO::MAP_LOCKED>,
1680	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2153	C<IO::AIO::MAP_NORESERVE>,
		2154	C<IO::AIO::MAP_POPULATE>,
1681	C<IO::AIO::MAP_NONBLOCK>	2155	C<IO::AIO::MAP_NONBLOCK>,
		2156	C<IO::AIO::MAP_FIXED>,
		2157	C<IO::AIO::MAP_GROWSDOWN>,
		2158	C<IO::AIO::MAP_32BIT>,
		2159	C<IO::AIO::MAP_HUGETLB> or
		2160	C<IO::AIO::MAP_STACK>.
1682		2161
1683	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2162	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1684		2163
1685	C<$offset> is the offset from the start of the file - it generally must be	2164	C<$offset> is the offset from the start of the file - it generally must be
1686	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2165	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1711		2190
1712	Calls the C<munlockall> function.	2191	Calls the C<munlockall> function.
1713		2192
1714	On systems that do not implement C<munlockall>, this function returns	2193	On systems that do not implement C<munlockall>, this function returns
1715	ENOSYS, otherwise the return value of C<munlockall>.	2194	ENOSYS, otherwise the return value of C<munlockall>.
		2195
		2196	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2197
		2198	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2199	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2200	should be the file offset.
		2201
		2202	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2203	silently corrupt the data in this case.
		2204
		2205	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2206	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2207	C<IO::AIO::SPLICE_F_GIFT>.
		2208
		2209	See the C<splice(2)> manpage for details.
		2210
		2211	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2212
		2213	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2214	description for C<IO::AIO::splice> above for details.
		2215
		2216	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2217
		2218	Attempts to query or change the pipe buffer size. Obviously works only
		2219	on pipes, and currently works only on GNU/Linux systems, and fails with
		2220	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2221	size on other systems, drop me a note.
		2222
		2223	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2224
		2225	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2226	C<$flags> is missing or C<0>, then this should be the same as a call to
		2227	perl's built-in C<pipe> function and create a new pipe, and works on
		2228	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2229	(..., 4096, O_BINARY)>.
		2230
		2231	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2232	the given flags (Linux 2.6.27, glibc 2.9).
		2233
		2234	On success, the read and write file handles are returned.
		2235
		2236	On error, nothing will be returned. If the pipe2 syscall is missing and
		2237	C<$flags> is non-zero, fails with C<ENOSYS>.
		2238
		2239	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2240	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2241	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1716		2242
1717	=back	2243	=back
1718		2244
1719	=cut	2245	=cut
1720		2246
…		…
1755	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2281	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1756	\&IO::AIO::poll_cb);	2282	\&IO::AIO::poll_cb);
1757		2283
1758	=head2 FORK BEHAVIOUR	2284	=head2 FORK BEHAVIOUR
1759		2285
1760	This module should do "the right thing" when the process using it forks:	2286	Usage of pthreads in a program changes the semantics of fork
		2287	considerably. Specifically, only async-safe functions can be called after
		2288	fork. Perl doesn't know about this, so in general, you cannot call fork
		2289	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2290	pthreads, so this applies, but many other extensions and (for inexplicable
		2291	reasons) perl itself often is linked against pthreads, so this limitation
		2292	applies to quite a lot of perls.
1761		2293
1762	Before the fork, IO::AIO enters a quiescent state where no requests	2294	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1763	can be added in other threads and no results will be processed. After	2295	only works in the process that loaded it. Forking is fully supported, but
1764	the fork the parent simply leaves the quiescent state and continues	2296	using IO::AIO in the child is not.
1765	request/result processing, while the child frees the request/result queue
1766	(so that the requests started before the fork will only be handled in the
1767	parent). Threads will be started on demand until the limit set in the
1768	parent process has been reached again.
1769		2297
1770	In short: the parent will, after a short pause, continue as if fork had	2298	You might get around by not I<using> IO::AIO before (or after)
1771	not been called, while the child will act as if IO::AIO has not been used	2299	forking. You could also try to call the L<IO::AIO::reinit> function in the
1772	yet.	2300	child:
		2301
		2302	=over 4
		2303
		2304	=item IO::AIO::reinit
		2305
		2306	Abandons all current requests and I/O threads and simply reinitialises all
		2307	data structures. This is not an operation supported by any standards, but
		2308	happens to work on GNU/Linux and some newer BSD systems.
		2309
		2310	The only reasonable use for this function is to call it after forking, if
		2311	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2312	the process will result in undefined behaviour. Calling it at any time
		2313	will also result in any undefined (by POSIX) behaviour.
		2314
		2315	=back
1773		2316
1774	=head2 MEMORY USAGE	2317	=head2 MEMORY USAGE
1775		2318
1776	Per-request usage:	2319	Per-request usage:
1777		2320

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.193 by root, Thu May 26 04:15:37 2011 UTC vs. Revision 1.273 by root, Fri Jun 23 22:33:06 2017 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.193 by root, Thu May 26 04:15:37 2011 UTC vs.
Revision 1.273 by root, Fri Jun 23 22:33:06 2017 UTC