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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.184 by root, Mon Nov 1 22:03:43 2010 UTC vs.
Revision 1.264 by root, Mon Jul 18 07:48:01 2016 UTC

…		…
68	=head2 EXAMPLE	68	=head2 EXAMPLE
69		69
70	This is a simple example that uses the EV module and loads	70	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
72		72
73	use Fcntl;
74	use EV;	73	use EV;
75	use IO::AIO;	74	use IO::AIO;
76		75
77	# register the IO::AIO callback with EV	76	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	77	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		94
96	# file contents now in $contents	95	# file contents now in $contents
97	print $contents;	96	print $contents;
98		97
99	# exit event loop and program	98	# exit event loop and program
100	EV::unloop;	99	EV::break;
101	};	100	};
102	};	101	};
103		102
104	# possibly queue up other requests, or open GUI windows,	103	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	104	# check for sockets etc. etc.
106		105
107	# process events as long as there are some:	106	# process events as long as there are some:
108	EV::loop;	107	EV::run;
109		108
110	=head1 REQUEST ANATOMY AND LIFETIME	109	=head1 REQUEST ANATOMY AND LIFETIME
111		110
112	Every C<aio_*> function creates a request. which is a C data structure not	111	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	112	directly visible to Perl.
…		…
168	use common::sense;	167	use common::sense;
169		168
170	use base 'Exporter';	169	use base 'Exporter';
171		170
172	BEGIN {	171	BEGIN {
173	our $VERSION = '3.7';	172	our $VERSION = 4.34;
174		173
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	174	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	175	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	176	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	177	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
		178	aio_pathsync aio_readahead aio_fiemap aio_allocate
179	aio_rename aio_link aio_move aio_copy aio_group	179	aio_rename aio_link aio_move aio_copy aio_group
180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181	aio_chmod aio_utime aio_truncate	181	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_mlock aio_mlockall	182	aio_msync aio_mtouch aio_mlock aio_mlockall
183	aio_statvfs);	183	aio_statvfs
		184	aio_wd);
184		185
185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
187	min_parallel max_parallel max_idle	188	min_parallel max_parallel max_idle idle_timeout
188	nreqs nready npending nthreads	189	nreqs nready npending nthreads
189	max_poll_time max_poll_reqs	190	max_poll_time max_poll_reqs
190	sendfile fadvise madvise	191	sendfile fadvise madvise
191	mmap munmap munlock munlockall);	192	mmap munmap munlock munlockall);
192		193
…		…
200		201
201	=head1 FUNCTIONS	202	=head1 FUNCTIONS
202		203
203	=head2 QUICK OVERVIEW	204	=head2 QUICK OVERVIEW
204		205
205	This section simply lists the prototypes of the most important functions	206	This section simply lists the prototypes most of the functions for
206	for quick reference. See the following sections for function-by-function	207	quick reference. See the following sections for function-by-function
207	documentation.	208	documentation.
208		209
		210	aio_wd $pathname, $callback->($wd)
209	aio_open $pathname, $flags, $mode, $callback->($fh)	211	aio_open $pathname, $flags, $mode, $callback->($fh)
210	aio_close $fh, $callback->($status)	212	aio_close $fh, $callback->($status)
		213	aio_seek $fh,$offset,$whence, $callback->($offs)
211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214	aio_readahead $fh,$offset,$length, $callback->($retval)	217	aio_readahead $fh,$offset,$length, $callback->($retval)
215	aio_stat $fh_or_path, $callback->($status)	218	aio_stat $fh_or_path, $callback->($status)
216	aio_lstat $fh, $callback->($status)	219	aio_lstat $fh, $callback->($status)
217	aio_statvfs $fh_or_path, $callback->($statvfs)	220	aio_statvfs $fh_or_path, $callback->($statvfs)
218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		223	aio_chmod $fh_or_path, $mode, $callback->($status)
220	aio_truncate $fh_or_path, $offset, $callback->($status)	224	aio_truncate $fh_or_path, $offset, $callback->($status)
221	aio_chmod $fh_or_path, $mode, $callback->($status)	225	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		226	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
222	aio_unlink $pathname, $callback->($status)	227	aio_unlink $pathname, $callback->($status)
223	aio_mknod $path, $mode, $dev, $callback->($status)	228	aio_mknod $pathname, $mode, $dev, $callback->($status)
224	aio_link $srcpath, $dstpath, $callback->($status)	229	aio_link $srcpath, $dstpath, $callback->($status)
225	aio_symlink $srcpath, $dstpath, $callback->($status)	230	aio_symlink $srcpath, $dstpath, $callback->($status)
226	aio_readlink $path, $callback->($link)	231	aio_readlink $pathname, $callback->($link)
		232	aio_realpath $pathname, $callback->($path)
227	aio_rename $srcpath, $dstpath, $callback->($status)	233	aio_rename $srcpath, $dstpath, $callback->($status)
228	aio_mkdir $pathname, $mode, $callback->($status)	234	aio_mkdir $pathname, $mode, $callback->($status)
229	aio_rmdir $pathname, $callback->($status)	235	aio_rmdir $pathname, $callback->($status)
230	aio_readdir $pathname, $callback->($entries)	236	aio_readdir $pathname, $callback->($entries)
231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	239	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		240	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
234	aio_load $path, $data, $callback->($status)	241	aio_load $pathname, $data, $callback->($status)
235	aio_copy $srcpath, $dstpath, $callback->($status)	242	aio_copy $srcpath, $dstpath, $callback->($status)
236	aio_move $srcpath, $dstpath, $callback->($status)	243	aio_move $srcpath, $dstpath, $callback->($status)
237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238	aio_rmtree $path, $callback->($status)	244	aio_rmtree $pathname, $callback->($status)
		245	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		246	aio_ioctl $fh, $request, $buf, $callback->($status)
239	aio_sync $callback->($status)	247	aio_sync $callback->($status)
		248	aio_syncfs $fh, $callback->($status)
240	aio_fsync $fh, $callback->($status)	249	aio_fsync $fh, $callback->($status)
241	aio_fdatasync $fh, $callback->($status)	250	aio_fdatasync $fh, $callback->($status)
242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	251	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243	aio_pathsync $path, $callback->($status)	252	aio_pathsync $pathname, $callback->($status)
244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	253	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	254	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	255	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247	aio_mlockall $flags, $callback->($status)	256	aio_mlockall $flags, $callback->($status)
248	aio_group $callback->(...)	257	aio_group $callback->(...)
…		…
258	IO::AIO::max_poll_reqs $nreqs	267	IO::AIO::max_poll_reqs $nreqs
259	IO::AIO::max_poll_time $seconds	268	IO::AIO::max_poll_time $seconds
260	IO::AIO::min_parallel $nthreads	269	IO::AIO::min_parallel $nthreads
261	IO::AIO::max_parallel $nthreads	270	IO::AIO::max_parallel $nthreads
262	IO::AIO::max_idle $nthreads	271	IO::AIO::max_idle $nthreads
		272	IO::AIO::idle_timeout $seconds
263	IO::AIO::max_outstanding $maxreqs	273	IO::AIO::max_outstanding $maxreqs
264	IO::AIO::nreqs	274	IO::AIO::nreqs
265	IO::AIO::nready	275	IO::AIO::nready
266	IO::AIO::npending	276	IO::AIO::npending
267		277
268	IO::AIO::sendfile $ofh, $ifh, $offset, $count	278	IO::AIO::sendfile $ofh, $ifh, $offset, $count
269	IO::AIO::fadvise $fh, $offset, $len, $advice	279	IO::AIO::fadvise $fh, $offset, $len, $advice
		280	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		281	IO::AIO::munmap $scalar
270	IO::AIO::madvise $scalar, $offset, $length, $advice	282	IO::AIO::madvise $scalar, $offset, $length, $advice
271	IO::AIO::mprotect $scalar, $offset, $length, $protect	283	IO::AIO::mprotect $scalar, $offset, $length, $protect
272	IO::AIO::munlock $scalar, $offset = 0, $length = undef	284	IO::AIO::munlock $scalar, $offset = 0, $length = undef
273	IO::AIO::munlockall	285	IO::AIO::munlockall
274		286
275	=head2 AIO REQUEST FUNCTIONS	287	=head2 API NOTES
276		288
277	All the C<aio_*> calls are more or less thin wrappers around the syscall	289	All the C<aio_*> calls are more or less thin wrappers around the syscall
278	with the same name (sans C<aio_>). The arguments are similar or identical,	290	with the same name (sans C<aio_>). The arguments are similar or identical,
279	and they all accept an additional (and optional) C<$callback> argument	291	and they all accept an additional (and optional) C<$callback> argument
280	which must be a code reference. This code reference will get called with	292	which must be a code reference. This code reference will be called after
281	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	293	the syscall has been executed in an asynchronous fashion. The results
282	perl, which usually delivers "false") as its sole argument after the given	294	of the request will be passed as arguments to the callback (and, if an
283	syscall has been executed asynchronously.	295	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		296	most syscalls return C<-1> on error, unlike perl, which usually delivers
		297	"false").
		298
		299	Some requests (such as C<aio_readdir>) pass the actual results and
		300	communicate failures by passing C<undef>.
284		301
285	All functions expecting a filehandle keep a copy of the filehandle	302	All functions expecting a filehandle keep a copy of the filehandle
286	internally until the request has finished.	303	internally until the request has finished.
287		304
288	All functions return request objects of type L<IO::AIO::REQ> that allow	305	All functions return request objects of type L<IO::AIO::REQ> that allow
289	further manipulation of those requests while they are in-flight.	306	further manipulation of those requests while they are in-flight.
290		307
291	The pathnames you pass to these routines I<must> be absolute and	308	The pathnames you pass to these routines I<should> be absolute. The
292	encoded as octets. The reason for the former is that at the time the	309	reason for this is that at the time the request is being executed, the
293	request is being executed, the current working directory could have	310	current working directory could have changed. Alternatively, you can
294	changed. Alternatively, you can make sure that you never change the	311	make sure that you never change the current working directory anywhere
295	current working directory anywhere in the program and then use relative	312	in the program and then use relative paths. You can also take advantage
296	paths.	313	of IO::AIOs working directory abstraction, that lets you specify paths
		314	relative to some previously-opened "working directory object" - see the
		315	description of the C<IO::AIO::WD> class later in this document.
297		316
298	To encode pathnames as octets, either make sure you either: a) always pass	317	To encode pathnames as octets, either make sure you either: a) always pass
299	in filenames you got from outside (command line, readdir etc.) without	318	in filenames you got from outside (command line, readdir etc.) without
300	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	319	tinkering, b) are in your native filesystem encoding, c) use the Encode
301	your pathnames to the locale (or other) encoding in effect in the user	320	module and encode your pathnames to the locale (or other) encoding in
302	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	321	effect in the user environment, d) use Glib::filename_from_unicode on
303	use something else to ensure your scalar has the correct contents.	322	unicode filenames or e) use something else to ensure your scalar has the
		323	correct contents.
304		324
305	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	325	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
306	handles correctly whether it is set or not.	326	handles correctly whether it is set or not.
		327
		328	=head2 AIO REQUEST FUNCTIONS
307		329
308	=over 4	330	=over 4
309		331
310	=item $prev_pri = aioreq_pri [$pri]	332	=item $prev_pri = aioreq_pri [$pri]
311		333
…		…
341		363
342		364
343	=item aio_open $pathname, $flags, $mode, $callback->($fh)	365	=item aio_open $pathname, $flags, $mode, $callback->($fh)
344		366
345	Asynchronously open or create a file and call the callback with a newly	367	Asynchronously open or create a file and call the callback with a newly
346	created filehandle for the file.	368	created filehandle for the file (or C<undef> in case of an error).
347		369
348	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	370	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
349	for an explanation.	371	for an explanation.
350		372
351	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	373	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
367	} else {	389	} else {
368	die "open failed: $!\n";	390	die "open failed: $!\n";
369	}	391	}
370	};	392	};
371		393
		394	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		395	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		396	following POSIX and non-POSIX constants are available (missing ones on
		397	your system are, as usual, C<0>):
		398
		399	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		400	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		401	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
		402
372		403
373	=item aio_close $fh, $callback->($status)	404	=item aio_close $fh, $callback->($status)
374		405
375	Asynchronously close a file and call the callback with the result	406	Asynchronously close a file and call the callback with the result
376	code.	407	code.
…		…
384		415
385	Or in other words: the file descriptor will be closed, but it will not be	416	Or in other words: the file descriptor will be closed, but it will not be
386	free for reuse until the perl filehandle is closed.	417	free for reuse until the perl filehandle is closed.
387		418
388	=cut	419	=cut
		420
		421	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		422
		423	Seeks the filehandle to the new C<$offset>, similarly to perl's
		424	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		425	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		426	C<IO::AIO::SEEK_END>).
		427
		428	The resulting absolute offset will be passed to the callback, or C<-1> in
		429	case of an error.
		430
		431	In theory, the C<$whence> constants could be different than the
		432	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		433	so don't panic.
		434
		435	As a GNU/Linux (and maybe Solaris) extension, also the constants
		436	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		437	could be found. No guarantees about suitability for use in C<aio_seek> or
		438	Perl's C<sysseek> can be made though, although I would naively assume they
		439	"just work".
389		440
390	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	441	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
391		442
392	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	443	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
393		444
…		…
426		477
427	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	478	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
428	reading at byte offset C<$in_offset>, and starts writing at the current	479	reading at byte offset C<$in_offset>, and starts writing at the current
429	file offset of C<$out_fh>. Because of that, it is not safe to issue more	480	file offset of C<$out_fh>. Because of that, it is not safe to issue more
430	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	481	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
431	other.	482	other. The same C<$in_fh> works fine though, as this function does not
		483	move or use the file offset of C<$in_fh>.
432		484
		485	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		486	are written, and there is no way to find out how many more bytes have been
		487	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		488	number of bytes written to C<$out_fh>. Only if the result value equals
		489	C<$length> one can assume that C<$length> bytes have been read.
		490
		491	Unlike with other C<aio_> functions, it makes a lot of sense to use
		492	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		493	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		494	the socket I/O will be non-blocking. Note, however, that you can run
		495	into a trap where C<aio_sendfile> reads some data with readahead, then
		496	fails to write all data, and when the socket is ready the next time, the
		497	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		498	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		499	resource usage.
		500
433	This call tries to make use of a native C<sendfile> syscall to provide	501	This call tries to make use of a native C<sendfile>-like syscall to
434	zero-copy operation. For this to work, C<$out_fh> should refer to a	502	provide zero-copy operation. For this to work, C<$out_fh> should refer to
435	socket, and C<$in_fh> should refer to an mmap'able file.	503	a socket, and C<$in_fh> should refer to an mmap'able file.
436		504
437	If a native sendfile cannot be found or it fails with C<ENOSYS>,	505	If a native sendfile cannot be found or it fails with C<ENOSYS>,
438	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	506	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
439	it will be emulated, so you can call C<aio_sendfile> on any type of	507	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
440	filehandle regardless of the limitations of the operating system.	508	type of filehandle regardless of the limitations of the operating system.
441		509
442	Please note, however, that C<aio_sendfile> can read more bytes from	510	As native sendfile syscalls (as practically any non-POSIX interface hacked
443	C<$in_fh> than are written, and there is no way to find out how many	511	together in a hurry to improve benchmark numbers) tend to be rather buggy
444	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	512	on many systems, this implementation tries to work around some known bugs
445	provides the number of bytes written to C<$out_fh>. Only if the result	513	in Linux and FreeBSD kernels (probably others, too), but that might fail,
446	value equals C<$length> one can assume that C<$length> bytes have been	514	so you really really should check the return value of C<aio_sendfile> -
447	read.	515	fewer bytes than expected might have been transferred.
448		516
449		517
450	=item aio_readahead $fh,$offset,$length, $callback->($retval)	518	=item aio_readahead $fh,$offset,$length, $callback->($retval)
451		519
452	C<aio_readahead> populates the page cache with data from a file so that	520	C<aio_readahead> populates the page cache with data from a file so that
…		…
456	whole pages, so that offset is effectively rounded down to a page boundary	524	whole pages, so that offset is effectively rounded down to a page boundary
457	and bytes are read up to the next page boundary greater than or equal to	525	and bytes are read up to the next page boundary greater than or equal to
458	(off-set+length). C<aio_readahead> does not read beyond the end of the	526	(off-set+length). C<aio_readahead> does not read beyond the end of the
459	file. The current file offset of the file is left unchanged.	527	file. The current file offset of the file is left unchanged.
460		528
461	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	529	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
462	emulated by simply reading the data, which would have a similar effect.	530	be emulated by simply reading the data, which would have a similar effect.
463		531
464		532
465	=item aio_stat $fh_or_path, $callback->($status)	533	=item aio_stat $fh_or_path, $callback->($status)
466		534
467	=item aio_lstat $fh, $callback->($status)	535	=item aio_lstat $fh, $callback->($status)
…		…
474	for an explanation.	542	for an explanation.
475		543
476	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	544	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
477	error when stat'ing a large file, the results will be silently truncated	545	error when stat'ing a large file, the results will be silently truncated
478	unless perl itself is compiled with large file support.	546	unless perl itself is compiled with large file support.
		547
		548	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		549	following constants and functions (if not implemented, the constants will
		550	be C<0> and the functions will either C<croak> or fall back on traditional
		551	behaviour).
		552
		553	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		554	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		555	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
479		556
480	Example: Print the length of F</etc/passwd>:	557	Example: Print the length of F</etc/passwd>:
481		558
482	aio_stat "/etc/passwd", sub {	559	aio_stat "/etc/passwd", sub {
483	$_[0] and die "stat failed: $!";	560	$_[0] and die "stat failed: $!";
…		…
527	namemax => 255,	604	namemax => 255,
528	frsize => 1024,	605	frsize => 1024,
529	fsid => 1810	606	fsid => 1810
530	}	607	}
531		608
		609	Here is a (likely partial - send me updates!) list of fsid values used by
		610	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		611
		612	0x0000adf5 adfs
		613	0x0000adff affs
		614	0x5346414f afs
		615	0x09041934 anon-inode filesystem
		616	0x00000187 autofs
		617	0x42465331 befs
		618	0x1badface bfs
		619	0x42494e4d binfmt_misc
		620	0x9123683e btrfs
		621	0x0027e0eb cgroupfs
		622	0xff534d42 cifs
		623	0x73757245 coda
		624	0x012ff7b7 coh
		625	0x28cd3d45 cramfs
		626	0x453dcd28 cramfs-wend (wrong endianness)
		627	0x64626720 debugfs
		628	0x00001373 devfs
		629	0x00001cd1 devpts
		630	0x0000f15f ecryptfs
		631	0x00414a53 efs
		632	0x0000137d ext
		633	0x0000ef53 ext2/ext3/ext4
		634	0x0000ef51 ext2
		635	0xf2f52010 f2fs
		636	0x00004006 fat
		637	0x65735546 fuseblk
		638	0x65735543 fusectl
		639	0x0bad1dea futexfs
		640	0x01161970 gfs2
		641	0x47504653 gpfs
		642	0x00004244 hfs
		643	0xf995e849 hpfs
		644	0x00c0ffee hostfs
		645	0x958458f6 hugetlbfs
		646	0x2bad1dea inotifyfs
		647	0x00009660 isofs
		648	0x000072b6 jffs2
		649	0x3153464a jfs
		650	0x6b414653 k-afs
		651	0x0bd00bd0 lustre
		652	0x0000137f minix
		653	0x0000138f minix 30 char names
		654	0x00002468 minix v2
		655	0x00002478 minix v2 30 char names
		656	0x00004d5a minix v3
		657	0x19800202 mqueue
		658	0x00004d44 msdos
		659	0x0000564c novell
		660	0x00006969 nfs
		661	0x6e667364 nfsd
		662	0x00003434 nilfs
		663	0x5346544e ntfs
		664	0x00009fa1 openprom
		665	0x7461636F ocfs2
		666	0x00009fa0 proc
		667	0x6165676c pstorefs
		668	0x0000002f qnx4
		669	0x68191122 qnx6
		670	0x858458f6 ramfs
		671	0x52654973 reiserfs
		672	0x00007275 romfs
		673	0x67596969 rpc_pipefs
		674	0x73636673 securityfs
		675	0xf97cff8c selinux
		676	0x0000517b smb
		677	0x534f434b sockfs
		678	0x73717368 squashfs
		679	0x62656572 sysfs
		680	0x012ff7b6 sysv2
		681	0x012ff7b5 sysv4
		682	0x01021994 tmpfs
		683	0x15013346 udf
		684	0x00011954 ufs
		685	0x54190100 ufs byteswapped
		686	0x00009fa2 usbdevfs
		687	0x01021997 v9fs
		688	0xa501fcf5 vxfs
		689	0xabba1974 xenfs
		690	0x012ff7b4 xenix
		691	0x58465342 xfs
		692	0x012fd16d xia
532		693
533	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	694	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
534		695
535	Works like perl's C<utime> function (including the special case of $atime	696	Works like perl's C<utime> function (including the special case of $atime
536	and $mtime being undef). Fractional times are supported if the underlying	697	and $mtime being undef). Fractional times are supported if the underlying
…		…
564	=item aio_truncate $fh_or_path, $offset, $callback->($status)	725	=item aio_truncate $fh_or_path, $offset, $callback->($status)
565		726
566	Works like truncate(2) or ftruncate(2).	727	Works like truncate(2) or ftruncate(2).
567		728
568		729
		730	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		731
		732	Allocates or frees disk space according to the C<$mode> argument. See the
		733	linux C<fallocate> documentation for details.
		734
		735	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		736	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		737	to deallocate a file range.
		738
		739	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		740	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		741	your L<fallocate(2)> manpage).
		742
		743	The file system block size used by C<fallocate> is presumably the
		744	C<f_bsize> returned by C<statvfs>.
		745
		746	If C<fallocate> isn't available or cannot be emulated (currently no
		747	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		748
		749
569	=item aio_chmod $fh_or_path, $mode, $callback->($status)	750	=item aio_chmod $fh_or_path, $mode, $callback->($status)
570		751
571	Works like perl's C<chmod> function.	752	Works like perl's C<chmod> function.
572		753
573		754
…		…
575		756
576	Asynchronously unlink (delete) a file and call the callback with the	757	Asynchronously unlink (delete) a file and call the callback with the
577	result code.	758	result code.
578		759
579		760
580	=item aio_mknod $path, $mode, $dev, $callback->($status)	761	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
581		762
582	[EXPERIMENTAL]	763	[EXPERIMENTAL]
583		764
584	Asynchronously create a device node (or fifo). See mknod(2).	765	Asynchronously create a device node (or fifo). See mknod(2).
585		766
586	The only (POSIX-) portable way of calling this function is:	767	The only (POSIX-) portable way of calling this function is:
587		768
588	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	769	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
589		770
		771	See C<aio_stat> for info about some potentially helpful extra constants
		772	and functions.
590		773
591	=item aio_link $srcpath, $dstpath, $callback->($status)	774	=item aio_link $srcpath, $dstpath, $callback->($status)
592		775
593	Asynchronously create a new link to the existing object at C<$srcpath> at	776	Asynchronously create a new link to the existing object at C<$srcpath> at
594	the path C<$dstpath> and call the callback with the result code.	777	the path C<$dstpath> and call the callback with the result code.
…		…
598		781
599	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	782	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
600	the path C<$dstpath> and call the callback with the result code.	783	the path C<$dstpath> and call the callback with the result code.
601		784
602		785
603	=item aio_readlink $path, $callback->($link)	786	=item aio_readlink $pathname, $callback->($link)
604		787
605	Asynchronously read the symlink specified by C<$path> and pass it to	788	Asynchronously read the symlink specified by C<$path> and pass it to
606	the callback. If an error occurs, nothing or undef gets passed to the	789	the callback. If an error occurs, nothing or undef gets passed to the
607	callback.	790	callback.
608		791
609		792
		793	=item aio_realpath $pathname, $callback->($path)
		794
		795	Asynchronously make the path absolute and resolve any symlinks in
		796	C<$path>. The resulting path only consists of directories (same as
		797	L<Cwd::realpath>).
		798
		799	This request can be used to get the absolute path of the current working
		800	directory by passing it a path of F<.> (a single dot).
		801
		802
610	=item aio_rename $srcpath, $dstpath, $callback->($status)	803	=item aio_rename $srcpath, $dstpath, $callback->($status)
611		804
612	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	805	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
613	rename(2) and call the callback with the result code.	806	rename(2) and call the callback with the result code.
		807
		808	On systems that support the AIO::WD working directory abstraction
		809	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		810	of failing, C<rename> is called on the absolute path of C<$wd>.
614		811
615		812
616	=item aio_mkdir $pathname, $mode, $callback->($status)	813	=item aio_mkdir $pathname, $mode, $callback->($status)
617		814
618	Asynchronously mkdir (create) a directory and call the callback with	815	Asynchronously mkdir (create) a directory and call the callback with
…		…
623	=item aio_rmdir $pathname, $callback->($status)	820	=item aio_rmdir $pathname, $callback->($status)
624		821
625	Asynchronously rmdir (delete) a directory and call the callback with the	822	Asynchronously rmdir (delete) a directory and call the callback with the
626	result code.	823	result code.
627		824
		825	On systems that support the AIO::WD working directory abstraction
		826	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		827	C<rmdir> is called on the absolute path of C<$wd>.
		828
628		829
629	=item aio_readdir $pathname, $callback->($entries)	830	=item aio_readdir $pathname, $callback->($entries)
630		831
631	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	832	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
632	directory (i.e. opendir + readdir + closedir). The entries will not be	833	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
636	array-ref with the filenames.	837	array-ref with the filenames.
637		838
638		839
639	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	840	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
640		841
641	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	842	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
642	behaviour and output format. In case of an error, C<$entries> will be	843	tune behaviour and output format. In case of an error, C<$entries> will be
643	C<undef>.	844	C<undef>.
644		845
645	The flags are a combination of the following constants, ORed together (the	846	The flags are a combination of the following constants, ORed together (the
646	flags will also be passed to the callback, possibly modified):	847	flags will also be passed to the callback, possibly modified):
647		848
648	=over 4	849	=over 4
649		850
650	=item IO::AIO::READDIR_DENTS	851	=item IO::AIO::READDIR_DENTS
651		852
652	When this flag is off, then the callback gets an arrayref with of names	853	When this flag is off, then the callback gets an arrayref consisting of
653	only (as with C<aio_readdir>), otherwise it gets an arrayref with	854	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
654	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	855	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
655	entry in more detail.	856	entry in more detail.
656		857
657	C<$name> is the name of the entry.	858	C<$name> is the name of the entry.
658		859
…		…
671	systems that do not deliver the inode information.	872	systems that do not deliver the inode information.
672		873
673	=item IO::AIO::READDIR_DIRS_FIRST	874	=item IO::AIO::READDIR_DIRS_FIRST
674		875
675	When this flag is set, then the names will be returned in an order where	876	When this flag is set, then the names will be returned in an order where
676	likely directories come first. This is useful when you need to quickly	877	likely directories come first, in optimal stat order. This is useful when
677	find directories, or you want to find all directories while avoiding to	878	you need to quickly find directories, or you want to find all directories
678	stat() each entry.	879	while avoiding to stat() each entry.
679		880
680	If the system returns type information in readdir, then this is used	881	If the system returns type information in readdir, then this is used
681	to find directories directly. Otherwise, likely directories are files	882	to find directories directly. Otherwise, likely directories are names
682	beginning with ".", or otherwise files with no dots, of which files with	883	beginning with ".", or otherwise names with no dots, of which names with
683	short names are tried first.	884	short names are tried first.
684		885
685	=item IO::AIO::READDIR_STAT_ORDER	886	=item IO::AIO::READDIR_STAT_ORDER
686		887
687	When this flag is set, then the names will be returned in an order	888	When this flag is set, then the names will be returned in an order
…		…
694		895
695	=item IO::AIO::READDIR_FOUND_UNKNOWN	896	=item IO::AIO::READDIR_FOUND_UNKNOWN
696		897
697	This flag should not be set when calling C<aio_readdirx>. Instead, it	898	This flag should not be set when calling C<aio_readdirx>. Instead, it
698	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	899	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
699	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	900	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
700	C<$type>'s are known, which can be used to speed up some algorithms.	901	C<$type>'s are known, which can be used to speed up some algorithms.
701		902
702	=back	903	=back
703		904
704		905
705	=item aio_load $path, $data, $callback->($status)	906	=item aio_load $pathname, $data, $callback->($status)
706		907
707	This is a composite request that tries to fully load the given file into	908	This is a composite request that tries to fully load the given file into
708	memory. Status is the same as with aio_read.	909	memory. Status is the same as with aio_read.
709		910
710	=cut	911	=cut
…		…
832	if ($_[0] && $! == EXDEV) {	1033	if ($_[0] && $! == EXDEV) {
833	aioreq_pri $pri;	1034	aioreq_pri $pri;
834	add $grp aio_copy $src, $dst, sub {	1035	add $grp aio_copy $src, $dst, sub {
835	$grp->result ($_[0]);	1036	$grp->result ($_[0]);
836		1037
837	if (!$_[0]) {	1038	unless ($_[0]) {
838	aioreq_pri $pri;	1039	aioreq_pri $pri;
839	add $grp aio_unlink $src;	1040	add $grp aio_unlink $src;
840	}	1041	}
841	};	1042	};
842	} else {	1043	} else {
…		…
845	};	1046	};
846		1047
847	$grp	1048	$grp
848	}	1049	}
849		1050
850	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1051	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
851		1052
852	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1053	Scans a directory (similar to C<aio_readdir>) but additionally tries to
853	efficiently separate the entries of directory C<$path> into two sets of	1054	efficiently separate the entries of directory C<$path> into two sets of
854	names, directories you can recurse into (directories), and ones you cannot	1055	names, directories you can recurse into (directories), and ones you cannot
855	recurse into (everything else, including symlinks to directories).	1056	recurse into (everything else, including symlinks to directories).
…		…
886	Then entries will be sorted into likely directories a non-initial dot	1087	Then entries will be sorted into likely directories a non-initial dot
887	currently) and likely non-directories (see C<aio_readdirx>). Then every	1088	currently) and likely non-directories (see C<aio_readdirx>). Then every
888	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1089	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
889	in order of their inode numbers. If that succeeds, it assumes that the	1090	in order of their inode numbers. If that succeeds, it assumes that the
890	entry is a directory or a symlink to directory (which will be checked	1091	entry is a directory or a symlink to directory (which will be checked
891	seperately). This is often faster than stat'ing the entry itself because	1092	separately). This is often faster than stat'ing the entry itself because
892	filesystems might detect the type of the entry without reading the inode	1093	filesystems might detect the type of the entry without reading the inode
893	data (e.g. ext2fs filetype feature), even on systems that cannot return	1094	data (e.g. ext2fs filetype feature), even on systems that cannot return
894	the filetype information on readdir.	1095	the filetype information on readdir.
895		1096
896	If the known number of directories (link count - 2) has been reached, the	1097	If the known number of directories (link count - 2) has been reached, the
…		…
912		1113
913	my $grp = aio_group $cb;	1114	my $grp = aio_group $cb;
914		1115
915	$maxreq = 4 if $maxreq <= 0;	1116	$maxreq = 4 if $maxreq <= 0;
916		1117
917	# stat once	1118	# get a wd object
918	aioreq_pri $pri;	1119	aioreq_pri $pri;
919	add $grp aio_stat $path, sub {	1120	add $grp aio_wd $path, sub {
		1121	$_[0]
920	return $grp->result () if $_[0];	1122	or return $grp->result ();
921	my $now = time;
922	my $hash1 = join ":", (stat _)[0,1,3,7,9];
923		1123
924	# read the directory entries	1124	my $wd = [shift, "."];
		1125
		1126	# stat once
925	aioreq_pri $pri;	1127	aioreq_pri $pri;
926	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1128	add $grp aio_stat $wd, sub {
927	my $entries = shift
928	or return $grp->result ();	1129	return $grp->result () if $_[0];
		1130	my $now = time;
		1131	my $hash1 = join ":", (stat _)[0,1,3,7,9];
929		1132
930	# stat the dir another time	1133	# read the directory entries
931	aioreq_pri $pri;	1134	aioreq_pri $pri;
		1135	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1136	my $entries = shift
		1137	or return $grp->result ();
		1138
		1139	# stat the dir another time
		1140	aioreq_pri $pri;
932	add $grp aio_stat $path, sub {	1141	add $grp aio_stat $wd, sub {
933	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1142	my $hash2 = join ":", (stat _)[0,1,3,7,9];
934		1143
935	my $ndirs;	1144	my $ndirs;
936		1145
937	# take the slow route if anything looks fishy	1146	# take the slow route if anything looks fishy
938	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1147	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
939	$ndirs = -1;	1148	$ndirs = -1;
940	} else {	1149	} else {
941	# if nlink == 2, we are finished	1150	# if nlink == 2, we are finished
942	# for non-posix-fs's, we rely on nlink < 2	1151	# for non-posix-fs's, we rely on nlink < 2
943	$ndirs = (stat _)[3] - 2	1152	$ndirs = (stat _)[3] - 2
944	or return $grp->result ([], $entries);	1153	or return $grp->result ([], $entries);
945	}	1154	}
946		1155
947	my (@dirs, @nondirs);	1156	my (@dirs, @nondirs);
948		1157
949	my $statgrp = add $grp aio_group sub {	1158	my $statgrp = add $grp aio_group sub {
950	$grp->result (\@dirs, \@nondirs);	1159	$grp->result (\@dirs, \@nondirs);
951	};	1160	};
952		1161
953	limit $statgrp $maxreq;	1162	limit $statgrp $maxreq;
954	feed $statgrp sub {	1163	feed $statgrp sub {
955	return unless @$entries;	1164	return unless @$entries;
956	my $entry = shift @$entries;	1165	my $entry = shift @$entries;
957		1166
958	aioreq_pri $pri;	1167	aioreq_pri $pri;
		1168	$wd->[1] = "$entry/.";
959	add $statgrp aio_stat "$path/$entry/.", sub {	1169	add $statgrp aio_stat $wd, sub {
960	if ($_[0] < 0) {	1170	if ($_[0] < 0) {
961	push @nondirs, $entry;	1171	push @nondirs, $entry;
962	} else {	1172	} else {
963	# need to check for real directory	1173	# need to check for real directory
964	aioreq_pri $pri;	1174	aioreq_pri $pri;
		1175	$wd->[1] = $entry;
965	add $statgrp aio_lstat "$path/$entry", sub {	1176	add $statgrp aio_lstat $wd, sub {
966	if (-d _) {	1177	if (-d _) {
967	push @dirs, $entry;	1178	push @dirs, $entry;
968		1179
969	unless (--$ndirs) {	1180	unless (--$ndirs) {
970	push @nondirs, @$entries;	1181	push @nondirs, @$entries;
971	feed $statgrp;	1182	feed $statgrp;
		1183	}
		1184	} else {
		1185	push @nondirs, $entry;
972	}	1186	}
973	} else {
974	push @nondirs, $entry;
975	}	1187	}
976	}	1188	}
977	}	1189	};
978	};	1190	};
979	};	1191	};
980	};	1192	};
981	};	1193	};
982	};	1194	};
983		1195
984	$grp	1196	$grp
985	}	1197	}
986		1198
987	=item aio_rmtree $path, $callback->($status)	1199	=item aio_rmtree $pathname, $callback->($status)
988		1200
989	Delete a directory tree starting (and including) C<$path>, return the	1201	Delete a directory tree starting (and including) C<$path>, return the
990	status of the final C<rmdir> only. This is a composite request that	1202	status of the final C<rmdir> only. This is a composite request that
991	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1203	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
992	everything else.	1204	everything else.
993		1205
994	=cut	1206	=cut
995		1207
…		…
1017	};	1229	};
1018		1230
1019	$grp	1231	$grp
1020	}	1232	}
1021		1233
		1234	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1235
		1236	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1237
		1238	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1239	they execute asynchronously and pass the return value to the callback.
		1240
		1241	Both calls can be used for a lot of things, some of which make more sense
		1242	to run asynchronously in their own thread, while some others make less
		1243	sense. For example, calls that block waiting for external events, such
		1244	as locking, will also lock down an I/O thread while it is waiting, which
		1245	can deadlock the whole I/O system. At the same time, there might be no
		1246	alternative to using a thread to wait.
		1247
		1248	So in general, you should only use these calls for things that do
		1249	(filesystem) I/O, not for things that wait for other events (network,
		1250	other processes), although if you are careful and know what you are doing,
		1251	you still can.
		1252
		1253	The following constants are available (missing ones are, as usual C<0>):
		1254
		1255	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1256
		1257	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1258	C<FS_IOC_FIEMAP>.
		1259
		1260	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1261	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1262
		1263	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1264	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1265	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1266	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1267	C<FS_FL_USER_MODIFIABLE>.
		1268
		1269	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1270	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1271	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1272	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
		1273
1022	=item aio_sync $callback->($status)	1274	=item aio_sync $callback->($status)
1023		1275
1024	Asynchronously call sync and call the callback when finished.	1276	Asynchronously call sync and call the callback when finished.
1025		1277
1026	=item aio_fsync $fh, $callback->($status)	1278	=item aio_fsync $fh, $callback->($status)
…		…
1033	Asynchronously call fdatasync on the given filehandle and call the	1285	Asynchronously call fdatasync on the given filehandle and call the
1034	callback with the fdatasync result code.	1286	callback with the fdatasync result code.
1035		1287
1036	If this call isn't available because your OS lacks it or it couldn't be	1288	If this call isn't available because your OS lacks it or it couldn't be
1037	detected, it will be emulated by calling C<fsync> instead.	1289	detected, it will be emulated by calling C<fsync> instead.
		1290
		1291	=item aio_syncfs $fh, $callback->($status)
		1292
		1293	Asynchronously call the syncfs syscall to sync the filesystem associated
		1294	to the given filehandle and call the callback with the syncfs result
		1295	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1296	errno to C<ENOSYS> nevertheless.
1038		1297
1039	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1298	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1040		1299
1041	Sync the data portion of the file specified by C<$offset> and C<$length>	1300	Sync the data portion of the file specified by C<$offset> and C<$length>
1042	to disk (but NOT the metadata), by calling the Linux-specific	1301	to disk (but NOT the metadata), by calling the Linux-specific
…		…
1046	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1305	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1047	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1306	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1048	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1307	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1049	manpage for details.	1308	manpage for details.
1050		1309
1051	=item aio_pathsync $path, $callback->($status)	1310	=item aio_pathsync $pathname, $callback->($status)
1052		1311
1053	This request tries to open, fsync and close the given path. This is a	1312	This request tries to open, fsync and close the given path. This is a
1054	composite request intended to sync directories after directory operations	1313	composite request intended to sync directories after directory operations
1055	(E.g. rename). This might not work on all operating systems or have any	1314	(E.g. rename). This might not work on all operating systems or have any
1056	specific effect, but usually it makes sure that directory changes get	1315	specific effect, but usually it makes sure that directory changes get
…		…
1108		1367
1109	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1368	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1110	scalars.	1369	scalars.
1111		1370
1112	It touches (reads or writes) all memory pages in the specified	1371	It touches (reads or writes) all memory pages in the specified
1113	range inside the scalar. All caveats and parameters are the same	1372	range inside the scalar. All caveats and parameters are the same
1114	as for C<aio_msync>, above, except for flags, which must be either	1373	as for C<aio_msync>, above, except for flags, which must be either
1115	C<0> (which reads all pages and ensures they are instantiated) or	1374	C<0> (which reads all pages and ensures they are instantiated) or
1116	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1375	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1117	writing an octet from it, which dirties the page).	1376	writing an octet from it, which dirties the page).
1118		1377
1119	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1378	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1120		1379
1121	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1380	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1152	documented under L<MISCELLANEOUS FUNCTIONS>.	1411	documented under L<MISCELLANEOUS FUNCTIONS>.
1153		1412
1154	Example: asynchronously lock all current and future pages into memory.	1413	Example: asynchronously lock all current and future pages into memory.
1155		1414
1156	aio_mlockall IO::AIO::MCL_FUTURE;	1415	aio_mlockall IO::AIO::MCL_FUTURE;
		1416
		1417	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1418
		1419	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1420	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1421	the ioctl is not available on your OS, then this request will fail with
		1422	C<ENOSYS>.
		1423
		1424	C<$start> is the starting offset to query extents for, C<$length> is the
		1425	size of the range to query - if it is C<undef>, then the whole file will
		1426	be queried.
		1427
		1428	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1429	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1430	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1431	the data portion.
		1432
		1433	C<$count> is the maximum number of extent records to return. If it is
		1434	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1435	case, if it is C<0>, then the callback receives the number of extents
		1436	instead of the extents themselves (which is unreliable, see below).
		1437
		1438	If an error occurs, the callback receives no arguments. The special
		1439	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1440
		1441	Otherwise, the callback receives an array reference with extent
		1442	structures. Each extent structure is an array reference itself, with the
		1443	following members:
		1444
		1445	[$logical, $physical, $length, $flags]
		1446
		1447	Flags is any combination of the following flag values (typically either C<0>
		1448	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1449
		1450	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1451	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1452	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1453	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1454	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1455	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1456
		1457	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1458	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1459	it to return all extents of a range for files with large number of
		1460	extents. The code works around all these issues if C<$count> is undef.
1157		1461
1158	=item aio_group $callback->(...)	1462	=item aio_group $callback->(...)
1159		1463
1160	This is a very special aio request: Instead of doing something, it is a	1464	This is a very special aio request: Instead of doing something, it is a
1161	container for other aio requests, which is useful if you want to bundle	1465	container for other aio requests, which is useful if you want to bundle
…		…
1198	like sleep and file handle readable/writable, the overhead this creates is	1502	like sleep and file handle readable/writable, the overhead this creates is
1199	immense (it blocks a thread for a long time) so do not use this function	1503	immense (it blocks a thread for a long time) so do not use this function
1200	except to put your application under artificial I/O pressure.	1504	except to put your application under artificial I/O pressure.
1201		1505
1202	=back	1506	=back
		1507
		1508
		1509	=head2 IO::AIO::WD - multiple working directories
		1510
		1511	Your process only has one current working directory, which is used by all
		1512	threads. This makes it hard to use relative paths (some other component
		1513	could call C<chdir> at any time, and it is hard to control when the path
		1514	will be used by IO::AIO).
		1515
		1516	One solution for this is to always use absolute paths. This usually works,
		1517	but can be quite slow (the kernel has to walk the whole path on every
		1518	access), and can also be a hassle to implement.
		1519
		1520	Newer POSIX systems have a number of functions (openat, fdopendir,
		1521	futimensat and so on) that make it possible to specify working directories
		1522	per operation.
		1523
		1524	For portability, and because the clowns who "designed", or shall I write,
		1525	perpetrated this new interface were obviously half-drunk, this abstraction
		1526	cannot be perfect, though.
		1527
		1528	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1529	object. This object stores the canonicalised, absolute version of the
		1530	path, and on systems that allow it, also a directory file descriptor.
		1531
		1532	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1533	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1534	object and a pathname instead (or the IO::AIO::WD object alone, which
		1535	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1536	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1537	to that IO::AIO::WD object.
		1538
		1539	For example, to get a wd object for F</etc> and then stat F<passwd>
		1540	inside, you would write:
		1541
		1542	aio_wd "/etc", sub {
		1543	my $etcdir = shift;
		1544
		1545	# although $etcdir can be undef on error, there is generally no reason
		1546	# to check for errors here, as aio_stat will fail with ENOENT
		1547	# when $etcdir is undef.
		1548
		1549	aio_stat [$etcdir, "passwd"], sub {
		1550	# yay
		1551	};
		1552	};
		1553
		1554	The fact that C<aio_wd> is a request and not a normal function shows that
		1555	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1556	which is why it is done asynchronously.
		1557
		1558	To stat the directory obtained with C<aio_wd> above, one could write
		1559	either of the following three request calls:
		1560
		1561	aio_lstat "/etc" , sub { ... # pathname as normal string
		1562	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1563	aio_lstat $wd , sub { ... # shorthand for the previous
		1564
		1565	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1566	object and the pathname string, so you could write the following without
		1567	causing any issues due to C<$path> getting reused:
		1568
		1569	my $path = [$wd, undef];
		1570
		1571	for my $name (qw(abc def ghi)) {
		1572	$path->[1] = $name;
		1573	aio_stat $path, sub {
		1574	# ...
		1575	};
		1576	}
		1577
		1578	There are some caveats: when directories get renamed (or deleted), the
		1579	pathname string doesn't change, so will point to the new directory (or
		1580	nowhere at all), while the directory fd, if available on the system,
		1581	will still point to the original directory. Most functions accepting a
		1582	pathname will use the directory fd on newer systems, and the string on
		1583	older systems. Some functions (such as realpath) will always rely on the
		1584	string form of the pathname.
		1585
		1586	So this functionality is mainly useful to get some protection against
		1587	C<chdir>, to easily get an absolute path out of a relative path for future
		1588	reference, and to speed up doing many operations in the same directory
		1589	(e.g. when stat'ing all files in a directory).
		1590
		1591	The following functions implement this working directory abstraction:
		1592
		1593	=over 4
		1594
		1595	=item aio_wd $pathname, $callback->($wd)
		1596
		1597	Asynchonously canonicalise the given pathname and convert it to an
		1598	IO::AIO::WD object representing it. If possible and supported on the
		1599	system, also open a directory fd to speed up pathname resolution relative
		1600	to this working directory.
		1601
		1602	If something goes wrong, then C<undef> is passwd to the callback instead
		1603	of a working directory object and C<$!> is set appropriately. Since
		1604	passing C<undef> as working directory component of a pathname fails the
		1605	request with C<ENOENT>, there is often no need for error checking in the
		1606	C<aio_wd> callback, as future requests using the value will fail in the
		1607	expected way.
		1608
		1609	=item IO::AIO::CWD
		1610
		1611	This is a compiletime constant (object) that represents the process
		1612	current working directory.
		1613
		1614	Specifying this object as working directory object for a pathname is as if
		1615	the pathname would be specified directly, without a directory object. For
		1616	example, these calls are functionally identical:
		1617
		1618	aio_stat "somefile", sub { ... };
		1619	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1620
		1621	=back
		1622
		1623	To recover the path associated with an IO::AIO::WD object, you can use
		1624	C<aio_realpath>:
		1625
		1626	aio_realpath $wd, sub {
		1627	warn "path is $_[0]\n";
		1628	};
		1629
		1630	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1631	sometimes, fall back to using an absolue path.
1203		1632
1204	=head2 IO::AIO::REQ CLASS	1633	=head2 IO::AIO::REQ CLASS
1205		1634
1206	All non-aggregate C<aio_*> functions return an object of this class when	1635	All non-aggregate C<aio_*> functions return an object of this class when
1207	called in non-void context.	1636	called in non-void context.
…		…
1325		1754
1326	Sets a feeder/generator on this group: every group can have an attached	1755	Sets a feeder/generator on this group: every group can have an attached
1327	generator that generates requests if idle. The idea behind this is that,	1756	generator that generates requests if idle. The idea behind this is that,
1328	although you could just queue as many requests as you want in a group,	1757	although you could just queue as many requests as you want in a group,
1329	this might starve other requests for a potentially long time. For example,	1758	this might starve other requests for a potentially long time. For example,
1330	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1759	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1331	delaying any later requests for a long time.	1760	requests, delaying any later requests for a long time.
1332		1761
1333	To avoid this, and allow incremental generation of requests, you can	1762	To avoid this, and allow incremental generation of requests, you can
1334	instead a group and set a feeder on it that generates those requests. The	1763	instead a group and set a feeder on it that generates those requests. The
1335	feed callback will be called whenever there are few enough (see C<limit>,	1764	feed callback will be called whenever there are few enough (see C<limit>,
1336	below) requests active in the group itself and is expected to queue more	1765	below) requests active in the group itself and is expected to queue more
…		…
1385		1814
1386	See C<poll_cb> for an example.	1815	See C<poll_cb> for an example.
1387		1816
1388	=item IO::AIO::poll_cb	1817	=item IO::AIO::poll_cb
1389		1818
1390	Process some outstanding events on the result pipe. You have to call this	1819	Process some requests that have reached the result phase (i.e. they have
1391	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1820	been executed but the results are not yet reported). You have to call
1392	returned earlier for whatever reason. Returns immediately when no events	1821	this "regularly" to finish outstanding requests.
1393	are outstanding. The amount of events processed depends on the settings of
1394	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1395		1822
		1823	Returns C<0> if all events could be processed (or there were no
		1824	events to process), or C<-1> if it returned earlier for whatever
		1825	reason. Returns immediately when no events are outstanding. The amount
		1826	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
		1827	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
		1828
1396	If not all requests were processed for whatever reason, the filehandle	1829	If not all requests were processed for whatever reason, the poll file
1397	will still be ready when C<poll_cb> returns, so normally you don't have to	1830	descriptor will still be ready when C<poll_cb> returns, so normally you
1398	do anything special to have it called later.	1831	don't have to do anything special to have it called later.
		1832
		1833	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1834	ready, it can be beneficial to call this function from loops which submit
		1835	a lot of requests, to make sure the results get processed when they become
		1836	available and not just when the loop is finished and the event loop takes
		1837	over again. This function returns very fast when there are no outstanding
		1838	requests.
1399		1839
1400	Example: Install an Event watcher that automatically calls	1840	Example: Install an Event watcher that automatically calls
1401	IO::AIO::poll_cb with high priority (more examples can be found in the	1841	IO::AIO::poll_cb with high priority (more examples can be found in the
1402	SYNOPSIS section, at the top of this document):	1842	SYNOPSIS section, at the top of this document):
1403		1843
…		…
1405	poll => 'r', async => 1,	1845	poll => 'r', async => 1,
1406	cb => \&IO::AIO::poll_cb);	1846	cb => \&IO::AIO::poll_cb);
1407		1847
1408	=item IO::AIO::poll_wait	1848	=item IO::AIO::poll_wait
1409		1849
1410	If there are any outstanding requests and none of them in the result	1850	Wait until either at least one request is in the result phase or no
1411	phase, wait till the result filehandle becomes ready for reading (simply	1851	requests are outstanding anymore.
1412	does a C<select> on the filehandle. This is useful if you want to	1852
1413	synchronously wait for some requests to finish).	1853	This is useful if you want to synchronously wait for some requests to
		1854	become ready, without actually handling them.
1414		1855
1415	See C<nreqs> for an example.	1856	See C<nreqs> for an example.
1416		1857
1417	=item IO::AIO::poll	1858	=item IO::AIO::poll
1418		1859
…		…
1505		1946
1506	Under normal circumstances you don't need to call this function.	1947	Under normal circumstances you don't need to call this function.
1507		1948
1508	=item IO::AIO::max_idle $nthreads	1949	=item IO::AIO::max_idle $nthreads
1509		1950
1510	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1951	Limit the number of threads (default: 4) that are allowed to idle
1511	threads that did not get a request to process within 10 seconds). That	1952	(i.e., threads that did not get a request to process within the idle
1512	means if a thread becomes idle while C<$nthreads> other threads are also	1953	timeout (default: 10 seconds). That means if a thread becomes idle while
1513	idle, it will free its resources and exit.	1954	C<$nthreads> other threads are also idle, it will free its resources and
		1955	exit.
1514		1956
1515	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1957	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1516	to allow for extremely high load situations, but want to free resources	1958	to allow for extremely high load situations, but want to free resources
1517	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1959	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1518		1960
1519	The default is probably ok in most situations, especially if thread	1961	The default is probably ok in most situations, especially if thread
1520	creation is fast. If thread creation is very slow on your system you might	1962	creation is fast. If thread creation is very slow on your system you might
1521	want to use larger values.	1963	want to use larger values.
1522		1964
		1965	=item IO::AIO::idle_timeout $seconds
		1966
		1967	Sets the minimum idle timeout (default 10) after which worker threads are
		1968	allowed to exit. SEe C<IO::AIO::max_idle>.
		1969
1523	=item IO::AIO::max_outstanding $maxreqs	1970	=item IO::AIO::max_outstanding $maxreqs
		1971
		1972	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1973	you do queue up more than this number of requests, the next call to
		1974	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1975	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1976	longer exceeded.
		1977
		1978	In other words, this setting does not enforce a queue limit, but can be
		1979	used to make poll functions block if the limit is exceeded.
1524		1980
1525	This is a very bad function to use in interactive programs because it	1981	This is a very bad function to use in interactive programs because it
1526	blocks, and a bad way to reduce concurrency because it is inexact: Better	1982	blocks, and a bad way to reduce concurrency because it is inexact: Better
1527	use an C<aio_group> together with a feed callback.	1983	use an C<aio_group> together with a feed callback.
1528		1984
1529	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1985	Its main use is in scripts without an event loop - when you want to stat
1530	do queue up more than this number of requests, the next call to the	1986	a lot of files, you can write somehting like this:
1531	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1532	function will block until the limit is no longer exceeded.
1533		1987
1534	The default value is very large, so there is no practical limit on the	1988	IO::AIO::max_outstanding 32;
1535	number of outstanding requests.
1536		1989
1537	You can still queue as many requests as you want. Therefore,	1990	for my $path (...) {
1538	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1991	aio_stat $path , ...;
1539	as a stop gap to shield against fatal memory overflow (with large values).	1992	IO::AIO::poll_cb;
		1993	}
		1994
		1995	IO::AIO::flush;
		1996
		1997	The call to C<poll_cb> inside the loop will normally return instantly, but
		1998	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1999	some requests have been handled. This keeps the loop from pushing a large
		2000	number of C<aio_stat> requests onto the queue.
		2001
		2002	The default value for C<max_outstanding> is very large, so there is no
		2003	practical limit on the number of outstanding requests.
1540		2004
1541	=back	2005	=back
1542		2006
1543	=head3 STATISTICAL INFORMATION	2007	=head3 STATISTICAL INFORMATION
1544		2008
…		…
1566		2030
1567	=back	2031	=back
1568		2032
1569	=head3 MISCELLANEOUS FUNCTIONS	2033	=head3 MISCELLANEOUS FUNCTIONS
1570		2034
1571	IO::AIO implements some functions that might be useful, but are not	2035	IO::AIO implements some functions that are useful when you want to use
1572	asynchronous.	2036	some "Advanced I/O" function not available to in Perl, without going the
		2037	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2038	counterpart.
1573		2039
1574	=over 4	2040	=over 4
1575		2041
1576	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2042	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1577		2043
…		…
1584		2050
1585	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2051	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1586		2052
1587	Simply calls the C<posix_fadvise> function (see its	2053	Simply calls the C<posix_fadvise> function (see its
1588	manpage for details). The following advice constants are	2054	manpage for details). The following advice constants are
1589	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2055	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1590	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2056	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1591	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2057	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1592		2058
1593	On systems that do not implement C<posix_fadvise>, this function returns	2059	On systems that do not implement C<posix_fadvise>, this function returns
1594	ENOSYS, otherwise the return value of C<posix_fadvise>.	2060	ENOSYS, otherwise the return value of C<posix_fadvise>.
1595		2061
1596	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2062	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1597		2063
1598	Simply calls the C<posix_madvise> function (see its	2064	Simply calls the C<posix_madvise> function (see its
1599	manpage for details). The following advice constants are	2065	manpage for details). The following advice constants are
1600	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2066	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1601	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2067	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>,
		2068	C<IO::AIO::MADV_FREE>.
1602		2069
1603	On systems that do not implement C<posix_madvise>, this function returns	2070	On systems that do not implement C<posix_madvise>, this function returns
1604	ENOSYS, otherwise the return value of C<posix_madvise>.	2071	ENOSYS, otherwise the return value of C<posix_madvise>.
1605		2072
1606	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2073	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1607		2074
1608	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2075	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1609	$scalar (see its manpage for details). The following protect	2076	$scalar (see its manpage for details). The following protect
1610	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2077	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1611	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2078	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1612		2079
1613	On systems that do not implement C<mprotect>, this function returns	2080	On systems that do not implement C<mprotect>, this function returns
1614	ENOSYS, otherwise the return value of C<mprotect>.	2081	ENOSYS, otherwise the return value of C<mprotect>.
1615		2082
1616	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2083	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1617		2084
1618	Memory-maps a file (or anonymous memory range) and attaches it to the	2085	Memory-maps a file (or anonymous memory range) and attaches it to the
1619	given C<$scalar>, which will act like a string scalar.	2086	given C<$scalar>, which will act like a string scalar. Returns true on
		2087	success, and false otherwise.
1620		2088
1621	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2089	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1622	change the string length, and most read-only operations such as copying it	2090	change the string length, and most read-only operations such as copying it
1623	or searching it with regexes and so on.	2091	or searching it with regexes and so on.
1624		2092
…		…
1635	filesize.	2103	filesize.
1636		2104
1637	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2105	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1638	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2106	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1639		2107
1640	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2108	C<$flags> can be a combination of
1641	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2109	C<IO::AIO::MAP_SHARED> or
1642	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2110	C<IO::AIO::MAP_PRIVATE>,
		2111	or a number of system-specific flags (when not available, the are C<0>):
1643	(which is set to C<MAP_ANON> if your system only provides this	2112	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1644	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2113	C<IO::AIO::MAP_LOCKED>,
1645	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2114	C<IO::AIO::MAP_NORESERVE>,
		2115	C<IO::AIO::MAP_POPULATE>,
1646	C<IO::AIO::MAP_NONBLOCK>	2116	C<IO::AIO::MAP_NONBLOCK>,
		2117	C<IO::AIO::MAP_FIXED>,
		2118	C<IO::AIO::MAP_GROWSDOWN>,
		2119	C<IO::AIO::MAP_32BIT>,
		2120	C<IO::AIO::MAP_HUGETLB> or
		2121	C<IO::AIO::MAP_STACK>.
1647		2122
1648	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2123	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1649		2124
1650	C<$offset> is the offset from the start of the file - it generally must be	2125	C<$offset> is the offset from the start of the file - it generally must be
1651	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2126	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1676		2151
1677	Calls the C<munlockall> function.	2152	Calls the C<munlockall> function.
1678		2153
1679	On systems that do not implement C<munlockall>, this function returns	2154	On systems that do not implement C<munlockall>, this function returns
1680	ENOSYS, otherwise the return value of C<munlockall>.	2155	ENOSYS, otherwise the return value of C<munlockall>.
		2156
		2157	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2158
		2159	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2160	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2161	should be the file offset.
		2162
		2163	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2164	silently corrupt the data in this case.
		2165
		2166	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2167	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2168	C<IO::AIO::SPLICE_F_GIFT>.
		2169
		2170	See the C<splice(2)> manpage for details.
		2171
		2172	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2173
		2174	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2175	description for C<IO::AIO::splice> above for details.
		2176
		2177	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2178
		2179	Attempts to query or change the pipe buffer size. Obviously works only
		2180	on pipes, and currently works only on GNU/Linux systems, and fails with
		2181	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2182	size on other systems, drop me a note.
		2183
		2184	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2185
		2186	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2187	C<$flags> is missing or C<0>, then this should be the same as a call to
		2188	perl's built-in C<pipe> function and create a new pipe, and works on
		2189	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2190	(..., 4096, O_BINARY)>.
		2191
		2192	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2193	the given flags (Linux 2.6.27, glibc 2.9).
		2194
		2195	On success, the read and write file handles are returned.
		2196
		2197	On error, nothing will be returned. If the pipe2 syscall is missing and
		2198	C<$flags> is non-zero, fails with C<ENOSYS>.
		2199
		2200	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2201	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2202	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1681		2203
1682	=back	2204	=back
1683		2205
1684	=cut	2206	=cut
1685		2207
…		…
1720	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2242	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1721	\&IO::AIO::poll_cb);	2243	\&IO::AIO::poll_cb);
1722		2244
1723	=head2 FORK BEHAVIOUR	2245	=head2 FORK BEHAVIOUR
1724		2246
1725	This module should do "the right thing" when the process using it forks:	2247	Usage of pthreads in a program changes the semantics of fork
		2248	considerably. Specifically, only async-safe functions can be called after
		2249	fork. Perl doesn't know about this, so in general, you cannot call fork
		2250	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2251	pthreads, so this applies, but many other extensions and (for inexplicable
		2252	reasons) perl itself often is linked against pthreads, so this limitation
		2253	applies to quite a lot of perls.
1726		2254
1727	Before the fork, IO::AIO enters a quiescent state where no requests	2255	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1728	can be added in other threads and no results will be processed. After	2256	only works in the process that loaded it. Forking is fully supported, but
1729	the fork the parent simply leaves the quiescent state and continues	2257	using IO::AIO in the child is not.
1730	request/result processing, while the child frees the request/result queue
1731	(so that the requests started before the fork will only be handled in the
1732	parent). Threads will be started on demand until the limit set in the
1733	parent process has been reached again.
1734		2258
1735	In short: the parent will, after a short pause, continue as if fork had	2259	You might get around by not I<using> IO::AIO before (or after)
1736	not been called, while the child will act as if IO::AIO has not been used	2260	forking. You could also try to call the L<IO::AIO::reinit> function in the
1737	yet.	2261	child:
		2262
		2263	=over 4
		2264
		2265	=item IO::AIO::reinit
		2266
		2267	Abandons all current requests and I/O threads and simply reinitialises all
		2268	data structures. This is not an operation supported by any standards, but
		2269	happens to work on GNU/Linux and some newer BSD systems.
		2270
		2271	The only reasonable use for this function is to call it after forking, if
		2272	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2273	the process will result in undefined behaviour. Calling it at any time
		2274	will also result in any undefined (by POSIX) behaviour.
		2275
		2276	=back
1738		2277
1739	=head2 MEMORY USAGE	2278	=head2 MEMORY USAGE
1740		2279
1741	Per-request usage:	2280	Per-request usage:
1742		2281

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.184 by root, Mon Nov 1 22:03:43 2010 UTC vs. Revision 1.264 by root, Mon Jul 18 07:48:01 2016 UTC

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Revision 1.184 by root, Mon Nov 1 22:03:43 2010 UTC vs.
Revision 1.264 by root, Mon Jul 18 07:48:01 2016 UTC