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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC vs.
Revision 1.284 by root, Fri Mar 23 01:14:08 2018 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 = '4.0';	176	our $VERSION = 4.4;
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_realpath aio_sync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179	aio_pathsync aio_readahead	182	aio_pathsync aio_readahead aio_fiemap aio_allocate
180	aio_rename aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181	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
182	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs	187	aio_statvfs
		188	aio_slurp
185	aio_wd);	189	aio_wd);
186		190
187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	191	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	192	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189	min_parallel max_parallel max_idle idle_timeout	193	min_parallel max_parallel max_idle idle_timeout
…		…
202		206
203	=head1 FUNCTIONS	207	=head1 FUNCTIONS
204		208
205	=head2 QUICK OVERVIEW	209	=head2 QUICK OVERVIEW
206		210
207	This section simply lists the prototypes of the most important functions	211	This section simply lists the prototypes most of the functions for
208	for quick reference. See the following sections for function-by-function	212	quick reference. See the following sections for function-by-function
209	documentation.	213	documentation.
210		214
211	aio_wd $pathname, $callback->($wd)	215	aio_wd $pathname, $callback->($wd)
212	aio_open $pathname, $flags, $mode, $callback->($fh)	216	aio_open $pathname, $flags, $mode, $callback->($fh)
213	aio_close $fh, $callback->($status)	217	aio_close $fh, $callback->($status)
		218	aio_seek $fh,$offset,$whence, $callback->($offs)
214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	219	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	220	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	221	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217	aio_readahead $fh,$offset,$length, $callback->($retval)	222	aio_readahead $fh,$offset,$length, $callback->($retval)
218	aio_stat $fh_or_path, $callback->($status)	223	aio_stat $fh_or_path, $callback->($status)
219	aio_lstat $fh, $callback->($status)	224	aio_lstat $fh, $callback->($status)
220	aio_statvfs $fh_or_path, $callback->($statvfs)	225	aio_statvfs $fh_or_path, $callback->($statvfs)
221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	226	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	227	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		228	aio_chmod $fh_or_path, $mode, $callback->($status)
223	aio_truncate $fh_or_path, $offset, $callback->($status)	229	aio_truncate $fh_or_path, $offset, $callback->($status)
224	aio_chmod $fh_or_path, $mode, $callback->($status)	230	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		231	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225	aio_unlink $pathname, $callback->($status)	232	aio_unlink $pathname, $callback->($status)
226	aio_mknod $pathname, $mode, $dev, $callback->($status)	233	aio_mknod $pathname, $mode, $dev, $callback->($status)
227	aio_link $srcpath, $dstpath, $callback->($status)	234	aio_link $srcpath, $dstpath, $callback->($status)
228	aio_symlink $srcpath, $dstpath, $callback->($status)	235	aio_symlink $srcpath, $dstpath, $callback->($status)
229	aio_readlink $pathname, $callback->($link)	236	aio_readlink $pathname, $callback->($link)
230	aio_realpath $pathname, $callback->($link)	237	aio_realpath $pathname, $callback->($path)
231	aio_rename $srcpath, $dstpath, $callback->($status)	238	aio_rename $srcpath, $dstpath, $callback->($status)
		239	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
232	aio_mkdir $pathname, $mode, $callback->($status)	240	aio_mkdir $pathname, $mode, $callback->($status)
233	aio_rmdir $pathname, $callback->($status)	241	aio_rmdir $pathname, $callback->($status)
234	aio_readdir $pathname, $callback->($entries)	242	aio_readdir $pathname, $callback->($entries)
235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	243	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	244	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	245	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		246	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238	aio_load $pathname, $data, $callback->($status)	247	aio_load $pathname, $data, $callback->($status)
239	aio_copy $srcpath, $dstpath, $callback->($status)	248	aio_copy $srcpath, $dstpath, $callback->($status)
240	aio_move $srcpath, $dstpath, $callback->($status)	249	aio_move $srcpath, $dstpath, $callback->($status)
241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242	aio_rmtree $pathname, $callback->($status)	250	aio_rmtree $pathname, $callback->($status)
		251	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		252	aio_ioctl $fh, $request, $buf, $callback->($status)
243	aio_sync $callback->($status)	253	aio_sync $callback->($status)
244	aio_syncfs $fh, $callback->($status)	254	aio_syncfs $fh, $callback->($status)
245	aio_fsync $fh, $callback->($status)	255	aio_fsync $fh, $callback->($status)
246	aio_fdatasync $fh, $callback->($status)	256	aio_fdatasync $fh, $callback->($status)
247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	257	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248	aio_pathsync $pathname, $callback->($status)	258	aio_pathsync $pathname, $callback->($status)
249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	260	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	261	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252	aio_mlockall $flags, $callback->($status)	262	aio_mlockall $flags, $callback->($status)
253	aio_group $callback->(...)	263	aio_group $callback->(...)
254	aio_nop $callback->()	264	aio_nop $callback->()
…		…
268	IO::AIO::idle_timeout $seconds	278	IO::AIO::idle_timeout $seconds
269	IO::AIO::max_outstanding $maxreqs	279	IO::AIO::max_outstanding $maxreqs
270	IO::AIO::nreqs	280	IO::AIO::nreqs
271	IO::AIO::nready	281	IO::AIO::nready
272	IO::AIO::npending	282	IO::AIO::npending
		283	$nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
		284	IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
273		285
274	IO::AIO::sendfile $ofh, $ifh, $offset, $count	286	IO::AIO::sendfile $ofh, $ifh, $offset, $count
275	IO::AIO::fadvise $fh, $offset, $len, $advice	287	IO::AIO::fadvise $fh, $offset, $len, $advice
		288	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		289	IO::AIO::munmap $scalar
276	IO::AIO::madvise $scalar, $offset, $length, $advice	290	IO::AIO::madvise $scalar, $offset, $length, $advice
277	IO::AIO::mprotect $scalar, $offset, $length, $protect	291	IO::AIO::mprotect $scalar, $offset, $length, $protect
278	IO::AIO::munlock $scalar, $offset = 0, $length = undef	292	IO::AIO::munlock $scalar, $offset = 0, $length = undef
279	IO::AIO::munlockall	293	IO::AIO::munlockall
280		294
281	=head2 AIO REQUEST FUNCTIONS	295	=head2 API NOTES
282		296
283	All the C<aio_*> calls are more or less thin wrappers around the syscall	297	All the C<aio_*> calls are more or less thin wrappers around the syscall
284	with the same name (sans C<aio_>). The arguments are similar or identical,	298	with the same name (sans C<aio_>). The arguments are similar or identical,
285	and they all accept an additional (and optional) C<$callback> argument	299	and they all accept an additional (and optional) C<$callback> argument
286	which must be a code reference. This code reference will get called with	300	which must be a code reference. This code reference will be called after
287	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	301	the syscall has been executed in an asynchronous fashion. The results
288	perl, which usually delivers "false") as its sole argument after the given	302	of the request will be passed as arguments to the callback (and, if an
289	syscall has been executed asynchronously.	303	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		304	most syscalls return C<-1> on error, unlike perl, which usually delivers
		305	"false").
		306
		307	Some requests (such as C<aio_readdir>) pass the actual results and
		308	communicate failures by passing C<undef>.
290		309
291	All functions expecting a filehandle keep a copy of the filehandle	310	All functions expecting a filehandle keep a copy of the filehandle
292	internally until the request has finished.	311	internally until the request has finished.
293		312
294	All functions return request objects of type L<IO::AIO::REQ> that allow	313	All functions return request objects of type L<IO::AIO::REQ> that allow
295	further manipulation of those requests while they are in-flight.	314	further manipulation of those requests while they are in-flight.
296		315
297	The pathnames you pass to these routines I<should> be absolute. The	316	The pathnames you pass to these routines I<should> be absolute. The
298	reason for this is that at the time the request is being executed, the	317	reason for this is that at the time the request is being executed, the
299	current working directory could have changed. Alternatively, you can make	318	current working directory could have changed. Alternatively, you can
300	sure that you never change the current working directory anywhere in	319	make sure that you never change the current working directory anywhere
301	the program and then use relative paths. Lastly, you can take advantage	320	in the program and then use relative paths. You can also take advantage
302	of IO::AIOs working directory abstraction - see the description of the	321	of IO::AIOs working directory abstraction, that lets you specify paths
		322	relative to some previously-opened "working directory object" - see the
303	C<IO::AIO::WD> class later in this document.	323	description of the C<IO::AIO::WD> class later in this document.
304		324
305	To encode pathnames as octets, either make sure you either: a) always pass	325	To encode pathnames as octets, either make sure you either: a) always pass
306	in filenames you got from outside (command line, readdir etc.) without	326	in filenames you got from outside (command line, readdir etc.) without
307	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	327	tinkering, b) are in your native filesystem encoding, c) use the Encode
308	your pathnames to the locale (or other) encoding in effect in the user	328	module and encode your pathnames to the locale (or other) encoding in
309	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	329	effect in the user environment, d) use Glib::filename_from_unicode on
310	use something else to ensure your scalar has the correct contents.	330	unicode filenames or e) use something else to ensure your scalar has the
		331	correct contents.
311		332
312	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	333	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
313	handles correctly whether it is set or not.	334	handles correctly whether it is set or not.
		335
		336	=head2 AIO REQUEST FUNCTIONS
314		337
315	=over 4	338	=over 4
316		339
317	=item $prev_pri = aioreq_pri [$pri]	340	=item $prev_pri = aioreq_pri [$pri]
318		341
…		…
348		371
349		372
350	=item aio_open $pathname, $flags, $mode, $callback->($fh)	373	=item aio_open $pathname, $flags, $mode, $callback->($fh)
351		374
352	Asynchronously open or create a file and call the callback with a newly	375	Asynchronously open or create a file and call the callback with a newly
353	created filehandle for the file.	376	created filehandle for the file (or C<undef> in case of an error).
354		377
355	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	378	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
356	for an explanation.	379	for an explanation.
357		380
358	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	381	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
381	following POSIX and non-POSIX constants are available (missing ones on	404	following POSIX and non-POSIX constants are available (missing ones on
382	your system are, as usual, C<0>):	405	your system are, as usual, C<0>):
383		406
384	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	407	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
385	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	408	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
386	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	409	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
387		410
388		411
389	=item aio_close $fh, $callback->($status)	412	=item aio_close $fh, $callback->($status)
390		413
391	Asynchronously close a file and call the callback with the result	414	Asynchronously close a file and call the callback with the result
…		…
401	Or in other words: the file descriptor will be closed, but it will not be	424	Or in other words: the file descriptor will be closed, but it will not be
402	free for reuse until the perl filehandle is closed.	425	free for reuse until the perl filehandle is closed.
403		426
404	=cut	427	=cut
405		428
		429	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		430
		431	Seeks the filehandle to the new C<$offset>, similarly to perl's
		432	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		433	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		434	C<IO::AIO::SEEK_END>).
		435
		436	The resulting absolute offset will be passed to the callback, or C<-1> in
		437	case of an error.
		438
		439	In theory, the C<$whence> constants could be different than the
		440	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		441	so don't panic.
		442
		443	As a GNU/Linux (and maybe Solaris) extension, also the constants
		444	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		445	could be found. No guarantees about suitability for use in C<aio_seek> or
		446	Perl's C<sysseek> can be made though, although I would naively assume they
		447	"just work".
		448
406	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	449	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
407		450
408	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	451	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
409		452
410	Reads or writes C<$length> bytes from or to the specified C<$fh> and	453	Reads or writes C<$length> bytes from or to the specified C<$fh> and
411	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	454	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
412	and calls the callback without the actual number of bytes read (or -1 on	455	calls the callback with the actual number of bytes transferred (or -1 on
413	error, just like the syscall).	456	error, just like the syscall).
414		457
415	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	458	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
416	offset plus the actual number of bytes read.	459	offset plus the actual number of bytes read.
417		460
…		…
475	As native sendfile syscalls (as practically any non-POSIX interface hacked	518	As native sendfile syscalls (as practically any non-POSIX interface hacked
476	together in a hurry to improve benchmark numbers) tend to be rather buggy	519	together in a hurry to improve benchmark numbers) tend to be rather buggy
477	on many systems, this implementation tries to work around some known bugs	520	on many systems, this implementation tries to work around some known bugs
478	in Linux and FreeBSD kernels (probably others, too), but that might fail,	521	in Linux and FreeBSD kernels (probably others, too), but that might fail,
479	so you really really should check the return value of C<aio_sendfile> -	522	so you really really should check the return value of C<aio_sendfile> -
480	fewre bytes than expected might have been transferred.	523	fewer bytes than expected might have been transferred.
481		524
482		525
483	=item aio_readahead $fh,$offset,$length, $callback->($retval)	526	=item aio_readahead $fh,$offset,$length, $callback->($retval)
484		527
485	C<aio_readahead> populates the page cache with data from a file so that	528	C<aio_readahead> populates the page cache with data from a file so that
…		…
489	whole pages, so that offset is effectively rounded down to a page boundary	532	whole pages, so that offset is effectively rounded down to a page boundary
490	and bytes are read up to the next page boundary greater than or equal to	533	and bytes are read up to the next page boundary greater than or equal to
491	(off-set+length). C<aio_readahead> does not read beyond the end of the	534	(off-set+length). C<aio_readahead> does not read beyond the end of the
492	file. The current file offset of the file is left unchanged.	535	file. The current file offset of the file is left unchanged.
493		536
494	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	537	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
495	emulated by simply reading the data, which would have a similar effect.	538	be emulated by simply reading the data, which would have a similar effect.
496		539
497		540
498	=item aio_stat $fh_or_path, $callback->($status)	541	=item aio_stat $fh_or_path, $callback->($status)
499		542
500	=item aio_lstat $fh, $callback->($status)	543	=item aio_lstat $fh, $callback->($status)
…		…
569	namemax => 255,	612	namemax => 255,
570	frsize => 1024,	613	frsize => 1024,
571	fsid => 1810	614	fsid => 1810
572	}	615	}
573		616
574
575	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	617	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
576		618
577	Works like perl's C<utime> function (including the special case of $atime	619	Works like perl's C<utime> function (including the special case of $atime
578	and $mtime being undef). Fractional times are supported if the underlying	620	and $mtime being undef). Fractional times are supported if the underlying
579	syscalls support them.	621	syscalls support them.
…		…
606	=item aio_truncate $fh_or_path, $offset, $callback->($status)	648	=item aio_truncate $fh_or_path, $offset, $callback->($status)
607		649
608	Works like truncate(2) or ftruncate(2).	650	Works like truncate(2) or ftruncate(2).
609		651
610		652
		653	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		654
		655	Allocates or frees disk space according to the C<$mode> argument. See the
		656	linux C<fallocate> documentation for details.
		657
		658	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		659	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		660	to deallocate a file range.
		661
		662	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		663	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		664	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		665	to unshare shared blocks (see your L<fallocate(2)> manpage).
		666
		667	The file system block size used by C<fallocate> is presumably the
		668	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		669	can dictate other limitations.
		670
		671	If C<fallocate> isn't available or cannot be emulated (currently no
		672	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		673
		674
611	=item aio_chmod $fh_or_path, $mode, $callback->($status)	675	=item aio_chmod $fh_or_path, $mode, $callback->($status)
612		676
613	Works like perl's C<chmod> function.	677	Works like perl's C<chmod> function.
614		678
615		679
…		…
652		716
653		717
654	=item aio_realpath $pathname, $callback->($path)	718	=item aio_realpath $pathname, $callback->($path)
655		719
656	Asynchronously make the path absolute and resolve any symlinks in	720	Asynchronously make the path absolute and resolve any symlinks in
657	C<$path>. The resulting path only consists of directories (Same as	721	C<$path>. The resulting path only consists of directories (same as
658	L<Cwd::realpath>).	722	L<Cwd::realpath>).
659		723
660	This request can be used to get the absolute path of the current working	724	This request can be used to get the absolute path of the current working
661	directory by passing it a path of F<.> (a single dot).	725	directory by passing it a path of F<.> (a single dot).
662		726
663		727
664	=item aio_rename $srcpath, $dstpath, $callback->($status)	728	=item aio_rename $srcpath, $dstpath, $callback->($status)
665		729
666	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	730	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
667	rename(2) and call the callback with the result code.	731	rename(2) and call the callback with the result code.
		732
		733	On systems that support the AIO::WD working directory abstraction
		734	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		735	of failing, C<rename> is called on the absolute path of C<$wd>.
		736
		737
		738	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		739
		740	Basically a version of C<aio_rename> with an additional C<$flags>
		741	argument. Calling this with C<$flags=0> is the same as calling
		742	C<aio_rename>.
		743
		744	Non-zero flags are currently only supported on GNU/Linux systems that
		745	support renameat2. Other systems fail with C<ENOSYS> in this case.
		746
		747	The following constants are available (missing ones are, as usual C<0>),
		748	see renameat2(2) for details:
		749
		750	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		751	and C<IO::AIO::RENAME_WHITEOUT>.
668		752
669		753
670	=item aio_mkdir $pathname, $mode, $callback->($status)	754	=item aio_mkdir $pathname, $mode, $callback->($status)
671		755
672	Asynchronously mkdir (create) a directory and call the callback with	756	Asynchronously mkdir (create) a directory and call the callback with
…		…
677	=item aio_rmdir $pathname, $callback->($status)	761	=item aio_rmdir $pathname, $callback->($status)
678		762
679	Asynchronously rmdir (delete) a directory and call the callback with the	763	Asynchronously rmdir (delete) a directory and call the callback with the
680	result code.	764	result code.
681		765
		766	On systems that support the AIO::WD working directory abstraction
		767	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		768	C<rmdir> is called on the absolute path of C<$wd>.
		769
682		770
683	=item aio_readdir $pathname, $callback->($entries)	771	=item aio_readdir $pathname, $callback->($entries)
684		772
685	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	773	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
686	directory (i.e. opendir + readdir + closedir). The entries will not be	774	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
701		789
702	=over 4	790	=over 4
703		791
704	=item IO::AIO::READDIR_DENTS	792	=item IO::AIO::READDIR_DENTS
705		793
706	When this flag is off, then the callback gets an arrayref consisting of	794	Normally the callback gets an arrayref consisting of names only (as
707	names only (as with C<aio_readdir>), otherwise it gets an arrayref with	795	with C<aio_readdir>). If this flag is set, then the callback gets an
708	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	796	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
709	entry in more detail.	797	single directory entry in more detail:
710		798
711	C<$name> is the name of the entry.	799	C<$name> is the name of the entry.
712		800
713	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	801	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
714		802
715	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	803	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
716	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	804	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
717	C<IO::AIO::DT_WHT>.	805	C<IO::AIO::DT_WHT>.
718		806
719	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	807	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
720	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	808	to know, you have to run stat yourself. Also, for speed/memory reasons,
721	scalars are read-only: you can not modify them.	809	the C<$type> scalars are read-only: you must not modify them.
722		810
723	C<$inode> is the inode number (which might not be exact on systems with 64	811	C<$inode> is the inode number (which might not be exact on systems with 64
724	bit inode numbers and 32 bit perls). This field has unspecified content on	812	bit inode numbers and 32 bit perls). This field has unspecified content on
725	systems that do not deliver the inode information.	813	systems that do not deliver the inode information.
726		814
…		…
737	short names are tried first.	825	short names are tried first.
738		826
739	=item IO::AIO::READDIR_STAT_ORDER	827	=item IO::AIO::READDIR_STAT_ORDER
740		828
741	When this flag is set, then the names will be returned in an order	829	When this flag is set, then the names will be returned in an order
742	suitable for stat()'ing each one. That is, when you plan to stat()	830	suitable for stat()'ing each one. That is, when you plan to stat() most or
743	all files in the given directory, then the returned order will likely	831	all files in the given directory, then the returned order will likely be
744	be fastest.	832	faster.
745		833
746	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	834	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
747	the likely dirs come first, resulting in a less optimal stat order.	835	then the likely dirs come first, resulting in a less optimal stat order
		836	for stat'ing all entries, but likely a more optimal order for finding
		837	subdirectories.
748		838
749	=item IO::AIO::READDIR_FOUND_UNKNOWN	839	=item IO::AIO::READDIR_FOUND_UNKNOWN
750		840
751	This flag should not be set when calling C<aio_readdirx>. Instead, it	841	This flag should not be set when calling C<aio_readdirx>. Instead, it
752	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	842	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
754	C<$type>'s are known, which can be used to speed up some algorithms.	844	C<$type>'s are known, which can be used to speed up some algorithms.
755		845
756	=back	846	=back
757		847
758		848
		849	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		850
		851	Opens, reads and closes the given file. The data is put into C<$data>,
		852	which is resized as required.
		853
		854	If C<$offset> is negative, then it is counted from the end of the file.
		855
		856	If C<$length> is zero, then the remaining length of the file is
		857	used. Also, in this case, the same limitations to modifying C<$data> apply
		858	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		859	with C<substr>. If the size of the file is known, specifying a non-zero
		860	C<$length> results in a performance advantage.
		861
		862	This request is similar to the older C<aio_load> request, but since it is
		863	a single request, it might be more efficient to use.
		864
		865	Example: load F</etc/passwd> into C<$passwd>.
		866
		867	my $passwd;
		868	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		869	$_[0] >= 0
		870	or die "/etc/passwd: $!\n";
		871
		872	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		873	print $passwd;
		874	};
		875	IO::AIO::flush;
		876
		877
759	=item aio_load $pathname, $data, $callback->($status)	878	=item aio_load $pathname, $data, $callback->($status)
760		879
761	This is a composite request that tries to fully load the given file into	880	This is a composite request that tries to fully load the given file into
762	memory. Status is the same as with aio_read.	881	memory. Status is the same as with aio_read.
		882
		883	Using C<aio_slurp> might be more efficient, as it is a single request.
763		884
764	=cut	885	=cut
765		886
766	sub aio_load($$;$) {	887	sub aio_load($$;$) {
767	my ($path, undef, $cb) = @_;	888	my ($path, undef, $cb) = @_;
…		…
787	=item aio_copy $srcpath, $dstpath, $callback->($status)	908	=item aio_copy $srcpath, $dstpath, $callback->($status)
788		909
789	Try to copy the I<file> (directories not supported as either source or	910	Try to copy the I<file> (directories not supported as either source or
790	destination) from C<$srcpath> to C<$dstpath> and call the callback with	911	destination) from C<$srcpath> to C<$dstpath> and call the callback with
791	a status of C<0> (ok) or C<-1> (error, see C<$!>).	912	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		913
		914	Existing destination files will be truncated.
792		915
793	This is a composite request that creates the destination file with	916	This is a composite request that creates the destination file with
794	mode 0200 and copies the contents of the source file into it using	917	mode 0200 and copies the contents of the source file into it using
795	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	918	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
796	uid/gid, in that order.	919	uid/gid, in that order.
…		…
906	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1029	Scans a directory (similar to C<aio_readdir>) but additionally tries to
907	efficiently separate the entries of directory C<$path> into two sets of	1030	efficiently separate the entries of directory C<$path> into two sets of
908	names, directories you can recurse into (directories), and ones you cannot	1031	names, directories you can recurse into (directories), and ones you cannot
909	recurse into (everything else, including symlinks to directories).	1032	recurse into (everything else, including symlinks to directories).
910		1033
911	C<aio_scandir> is a composite request that creates of many sub requests_	1034	C<aio_scandir> is a composite request that generates many sub requests.
912	C<$maxreq> specifies the maximum number of outstanding aio requests that	1035	C<$maxreq> specifies the maximum number of outstanding aio requests that
913	this function generates. If it is C<< <= 0 >>, then a suitable default	1036	this function generates. If it is C<< <= 0 >>, then a suitable default
914	will be chosen (currently 4).	1037	will be chosen (currently 4).
915		1038
916	On error, the callback is called without arguments, otherwise it receives	1039	On error, the callback is called without arguments, otherwise it receives
…		…
966		1089
967	my $grp = aio_group $cb;	1090	my $grp = aio_group $cb;
968		1091
969	$maxreq = 4 if $maxreq <= 0;	1092	$maxreq = 4 if $maxreq <= 0;
970		1093
971	# stat once	1094	# get a wd object
972	aioreq_pri $pri;	1095	aioreq_pri $pri;
973	add $grp aio_stat $path, sub {	1096	add $grp aio_wd $path, sub {
		1097	$_[0]
974	return $grp->result () if $_[0];	1098	or return $grp->result ();
975	my $now = time;
976	my $hash1 = join ":", (stat _)[0,1,3,7,9];
977		1099
978	# read the directory entries	1100	my $wd = [shift, "."];
		1101
		1102	# stat once
979	aioreq_pri $pri;	1103	aioreq_pri $pri;
980	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1104	add $grp aio_stat $wd, sub {
981	my $entries = shift
982	or return $grp->result ();	1105	return $grp->result () if $_[0];
		1106	my $now = time;
		1107	my $hash1 = join ":", (stat _)[0,1,3,7,9];
983		1108
984	# stat the dir another time	1109	# read the directory entries
985	aioreq_pri $pri;	1110	aioreq_pri $pri;
		1111	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1112	my $entries = shift
		1113	or return $grp->result ();
		1114
		1115	# stat the dir another time
		1116	aioreq_pri $pri;
986	add $grp aio_stat $path, sub {	1117	add $grp aio_stat $wd, sub {
987	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1118	my $hash2 = join ":", (stat _)[0,1,3,7,9];
988		1119
989	my $ndirs;	1120	my $ndirs;
990		1121
991	# take the slow route if anything looks fishy	1122	# take the slow route if anything looks fishy
992	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1123	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
993	$ndirs = -1;	1124	$ndirs = -1;
994	} else {	1125	} else {
995	# if nlink == 2, we are finished	1126	# if nlink == 2, we are finished
996	# for non-posix-fs's, we rely on nlink < 2	1127	# for non-posix-fs's, we rely on nlink < 2
997	$ndirs = (stat _)[3] - 2	1128	$ndirs = (stat _)[3] - 2
998	or return $grp->result ([], $entries);	1129	or return $grp->result ([], $entries);
999	}	1130	}
1000		1131
1001	my (@dirs, @nondirs);	1132	my (@dirs, @nondirs);
1002		1133
1003	my $statgrp = add $grp aio_group sub {	1134	my $statgrp = add $grp aio_group sub {
1004	$grp->result (\@dirs, \@nondirs);	1135	$grp->result (\@dirs, \@nondirs);
1005	};	1136	};
1006		1137
1007	limit $statgrp $maxreq;	1138	limit $statgrp $maxreq;
1008	feed $statgrp sub {	1139	feed $statgrp sub {
1009	return unless @$entries;	1140	return unless @$entries;
1010	my $entry = shift @$entries;	1141	my $entry = shift @$entries;
1011		1142
1012	aioreq_pri $pri;	1143	aioreq_pri $pri;
		1144	$wd->[1] = "$entry/.";
1013	add $statgrp aio_stat "$path/$entry/.", sub {	1145	add $statgrp aio_stat $wd, sub {
1014	if ($_[0] < 0) {	1146	if ($_[0] < 0) {
1015	push @nondirs, $entry;	1147	push @nondirs, $entry;
1016	} else {	1148	} else {
1017	# need to check for real directory	1149	# need to check for real directory
1018	aioreq_pri $pri;	1150	aioreq_pri $pri;
		1151	$wd->[1] = $entry;
1019	add $statgrp aio_lstat "$path/$entry", sub {	1152	add $statgrp aio_lstat $wd, sub {
1020	if (-d _) {	1153	if (-d _) {
1021	push @dirs, $entry;	1154	push @dirs, $entry;
1022		1155
1023	unless (--$ndirs) {	1156	unless (--$ndirs) {
1024	push @nondirs, @$entries;	1157	push @nondirs, @$entries;
1025	feed $statgrp;	1158	feed $statgrp;
		1159	}
		1160	} else {
		1161	push @nondirs, $entry;
1026	}	1162	}
1027	} else {
1028	push @nondirs, $entry;
1029	}	1163	}
1030	}	1164	}
1031	}	1165	};
1032	};	1166	};
1033	};	1167	};
1034	};	1168	};
1035	};	1169	};
1036	};	1170	};
…		…
1039	}	1173	}
1040		1174
1041	=item aio_rmtree $pathname, $callback->($status)	1175	=item aio_rmtree $pathname, $callback->($status)
1042		1176
1043	Delete a directory tree starting (and including) C<$path>, return the	1177	Delete a directory tree starting (and including) C<$path>, return the
1044	status of the final C<rmdir> only. This is a composite request that	1178	status of the final C<rmdir> only. This is a composite request that
1045	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1179	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1046	everything else.	1180	everything else.
1047		1181
1048	=cut	1182	=cut
1049		1183
…		…
1070	add $grp $dirgrp;	1204	add $grp $dirgrp;
1071	};	1205	};
1072		1206
1073	$grp	1207	$grp
1074	}	1208	}
		1209
		1210	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1211
		1212	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1213
		1214	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1215	they execute asynchronously and pass the return value to the callback.
		1216
		1217	Both calls can be used for a lot of things, some of which make more sense
		1218	to run asynchronously in their own thread, while some others make less
		1219	sense. For example, calls that block waiting for external events, such
		1220	as locking, will also lock down an I/O thread while it is waiting, which
		1221	can deadlock the whole I/O system. At the same time, there might be no
		1222	alternative to using a thread to wait.
		1223
		1224	So in general, you should only use these calls for things that do
		1225	(filesystem) I/O, not for things that wait for other events (network,
		1226	other processes), although if you are careful and know what you are doing,
		1227	you still can.
		1228
		1229	The following constants are available (missing ones are, as usual C<0>):
		1230
		1231	C<F_DUPFD_CLOEXEC>,
		1232
		1233	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1234
		1235	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1236
		1237	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1238	C<FS_IOC_FIEMAP>.
		1239
		1240	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1241	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1242
		1243	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1244	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1245	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1246	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1247	C<FS_FL_USER_MODIFIABLE>.
		1248
		1249	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1250	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1251	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1252	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1075		1253
1076	=item aio_sync $callback->($status)	1254	=item aio_sync $callback->($status)
1077		1255
1078	Asynchronously call sync and call the callback when finished.	1256	Asynchronously call sync and call the callback when finished.
1079		1257
…		…
1148	};	1326	};
1149		1327
1150	$grp	1328	$grp
1151	}	1329	}
1152		1330
1153	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1331	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1154		1332
1155	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1333	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1156	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1334	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1157	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1335	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1158	scalar must only be modified in-place while an aio operation is pending on	1336	scalar must only be modified in-place while an aio operation is pending on
…		…
1160		1338
1161	It calls the C<msync> function of your OS, if available, with the memory	1339	It calls the C<msync> function of your OS, if available, with the memory
1162	area starting at C<$offset> in the string and ending C<$length> bytes	1340	area starting at C<$offset> in the string and ending C<$length> bytes
1163	later. If C<$length> is negative, counts from the end, and if C<$length>	1341	later. If C<$length> is negative, counts from the end, and if C<$length>
1164	is C<undef>, then it goes till the end of the string. The flags can be	1342	is C<undef>, then it goes till the end of the string. The flags can be
1165	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1343	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1166	C<IO::AIO::MS_SYNC>.	1344	C<IO::AIO::MS_INVALIDATE>.
1167		1345
1168	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1346	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1169		1347
1170	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1348	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1171	scalars.	1349	scalars.
1172		1350
1173	It touches (reads or writes) all memory pages in the specified	1351	It touches (reads or writes) all memory pages in the specified
1174	range inside the scalar. All caveats and parameters are the same	1352	range inside the scalar. All caveats and parameters are the same
1175	as for C<aio_msync>, above, except for flags, which must be either	1353	as for C<aio_msync>, above, except for flags, which must be either
1176	C<0> (which reads all pages and ensures they are instantiated) or	1354	C<0> (which reads all pages and ensures they are instantiated) or
1177	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1355	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1178	writing an octet from it, which dirties the page).	1356	writing an octet from it, which dirties the page).
1179		1357
1180	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1358	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1181		1359
1182	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1360	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1213	documented under L<MISCELLANEOUS FUNCTIONS>.	1391	documented under L<MISCELLANEOUS FUNCTIONS>.
1214		1392
1215	Example: asynchronously lock all current and future pages into memory.	1393	Example: asynchronously lock all current and future pages into memory.
1216		1394
1217	aio_mlockall IO::AIO::MCL_FUTURE;	1395	aio_mlockall IO::AIO::MCL_FUTURE;
		1396
		1397	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1398
		1399	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1400	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1401	the ioctl is not available on your OS, then this request will fail with
		1402	C<ENOSYS>.
		1403
		1404	C<$start> is the starting offset to query extents for, C<$length> is the
		1405	size of the range to query - if it is C<undef>, then the whole file will
		1406	be queried.
		1407
		1408	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1409	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1410	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1411	the data portion.
		1412
		1413	C<$count> is the maximum number of extent records to return. If it is
		1414	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1415	case, if it is C<0>, then the callback receives the number of extents
		1416	instead of the extents themselves (which is unreliable, see below).
		1417
		1418	If an error occurs, the callback receives no arguments. The special
		1419	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1420
		1421	Otherwise, the callback receives an array reference with extent
		1422	structures. Each extent structure is an array reference itself, with the
		1423	following members:
		1424
		1425	[$logical, $physical, $length, $flags]
		1426
		1427	Flags is any combination of the following flag values (typically either C<0>
		1428	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1429
		1430	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1431	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1432	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1433	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1434	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1435	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1436
		1437	At the time of this writing (Linux 3.2), this request is unreliable unless
		1438	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1439	it to return all extents of a range for files with a large number of
		1440	extents. The code (only) works around all these issues if C<$count> is
		1441	C<undef>.
1218		1442
1219	=item aio_group $callback->(...)	1443	=item aio_group $callback->(...)
1220		1444
1221	This is a very special aio request: Instead of doing something, it is a	1445	This is a very special aio request: Instead of doing something, it is a
1222	container for other aio requests, which is useful if you want to bundle	1446	container for other aio requests, which is useful if you want to bundle
…		…
1286	object. This object stores the canonicalised, absolute version of the	1510	object. This object stores the canonicalised, absolute version of the
1287	path, and on systems that allow it, also a directory file descriptor.	1511	path, and on systems that allow it, also a directory file descriptor.
1288		1512
1289	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>	1513	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1290	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD	1514	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1291	object and a pathname instead. If the pathname is absolute, the	1515	object and a pathname instead (or the IO::AIO::WD object alone, which
		1516	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1292	IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative	1517	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1293	to that IO::AIO::WD object.	1518	to that IO::AIO::WD object.
1294		1519
1295	For example, to get a wd object for F</etc> and then stat F<passwd>	1520	For example, to get a wd object for F</etc> and then stat F<passwd>
1296	inside, you would write:	1521	inside, you would write:
1297		1522
…		…
1305	aio_stat [$etcdir, "passwd"], sub {	1530	aio_stat [$etcdir, "passwd"], sub {
1306	# yay	1531	# yay
1307	};	1532	};
1308	};	1533	};
1309		1534
		1535	The fact that C<aio_wd> is a request and not a normal function shows that
1310	This shows that creating an IO::AIO::WD object is itself a potentially	1536	creating an IO::AIO::WD object is itself a potentially blocking operation,
1311	blocking operation, which is why it is done asynchronously.	1537	which is why it is done asynchronously.
		1538
		1539	To stat the directory obtained with C<aio_wd> above, one could write
		1540	either of the following three request calls:
		1541
		1542	aio_lstat "/etc" , sub { ... # pathname as normal string
		1543	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1544	aio_lstat $wd , sub { ... # shorthand for the previous
1312		1545
1313	As with normal pathnames, IO::AIO keeps a copy of the working directory	1546	As with normal pathnames, IO::AIO keeps a copy of the working directory
1314	object and the pathname string, so you could write the following without	1547	object and the pathname string, so you could write the following without
1315	causing any issues due to C<$path> getting reused:	1548	causing any issues due to C<$path> getting reused:
1316		1549
…		…
1326	There are some caveats: when directories get renamed (or deleted), the	1559	There are some caveats: when directories get renamed (or deleted), the
1327	pathname string doesn't change, so will point to the new directory (or	1560	pathname string doesn't change, so will point to the new directory (or
1328	nowhere at all), while the directory fd, if available on the system,	1561	nowhere at all), while the directory fd, if available on the system,
1329	will still point to the original directory. Most functions accepting a	1562	will still point to the original directory. Most functions accepting a
1330	pathname will use the directory fd on newer systems, and the string on	1563	pathname will use the directory fd on newer systems, and the string on
1331	older systems. Some functions (such as realpath) will always rely on the	1564	older systems. Some functions (such as C<aio_realpath>) will always rely on
1332	string form of the pathname.	1565	the string form of the pathname.
1333		1566
1334	So this fucntionality is mainly useful to get some protection against	1567	So this functionality is mainly useful to get some protection against
1335	C<chdir>, to easily get an absolute path out of a relative path for future	1568	C<chdir>, to easily get an absolute path out of a relative path for future
1336	reference, and to speed up doing many operations in the same directory	1569	reference, and to speed up doing many operations in the same directory
1337	(e.g. when stat'ing all files in a directory).	1570	(e.g. when stat'ing all files in a directory).
1338		1571
1339	The following functions implement this working directory abstraction:	1572	The following functions implement this working directory abstraction:
…		…
1352	passing C<undef> as working directory component of a pathname fails the	1585	passing C<undef> as working directory component of a pathname fails the
1353	request with C<ENOENT>, there is often no need for error checking in the	1586	request with C<ENOENT>, there is often no need for error checking in the
1354	C<aio_wd> callback, as future requests using the value will fail in the	1587	C<aio_wd> callback, as future requests using the value will fail in the
1355	expected way.	1588	expected way.
1356		1589
1357	If this call isn't available because your OS lacks it or it couldn't be
1358	detected, it will be emulated by calling C<fsync> instead.
1359
1360	=item IO::AIO::CWD	1590	=item IO::AIO::CWD
1361		1591
1362	This is a compiletime constant (object) that represents the process	1592	This is a compiletime constant (object) that represents the process
1363	current working directory.	1593	current working directory.
1364		1594
1365	Specifying this object as working directory object for a pathname is as	1595	Specifying this object as working directory object for a pathname is as if
1366	if the pathname would be specified directly, without a directory object,	1596	the pathname would be specified directly, without a directory object. For
1367	e.g., these calls are functionally identical:	1597	example, these calls are functionally identical:
1368		1598
1369	aio_stat "somefile", sub { ... };	1599	aio_stat "somefile", sub { ... };
1370	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1600	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1371		1601
1372	=back	1602	=back
1373		1603
		1604	To recover the path associated with an IO::AIO::WD object, you can use
		1605	C<aio_realpath>:
		1606
		1607	aio_realpath $wd, sub {
		1608	warn "path is $_[0]\n";
		1609	};
		1610
		1611	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1612	sometimes, fall back to using an absolue path.
1374		1613
1375	=head2 IO::AIO::REQ CLASS	1614	=head2 IO::AIO::REQ CLASS
1376		1615
1377	All non-aggregate C<aio_*> functions return an object of this class when	1616	All non-aggregate C<aio_*> functions return an object of this class when
1378	called in non-void context.	1617	called in non-void context.
…		…
1496		1735
1497	Sets a feeder/generator on this group: every group can have an attached	1736	Sets a feeder/generator on this group: every group can have an attached
1498	generator that generates requests if idle. The idea behind this is that,	1737	generator that generates requests if idle. The idea behind this is that,
1499	although you could just queue as many requests as you want in a group,	1738	although you could just queue as many requests as you want in a group,
1500	this might starve other requests for a potentially long time. For example,	1739	this might starve other requests for a potentially long time. For example,
1501	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1740	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1502	delaying any later requests for a long time.	1741	requests, delaying any later requests for a long time.
1503		1742
1504	To avoid this, and allow incremental generation of requests, you can	1743	To avoid this, and allow incremental generation of requests, you can
1505	instead a group and set a feeder on it that generates those requests. The	1744	instead a group and set a feeder on it that generates those requests. The
1506	feed callback will be called whenever there are few enough (see C<limit>,	1745	feed callback will be called whenever there are few enough (see C<limit>,
1507	below) requests active in the group itself and is expected to queue more	1746	below) requests active in the group itself and is expected to queue more
…		…
1556		1795
1557	See C<poll_cb> for an example.	1796	See C<poll_cb> for an example.
1558		1797
1559	=item IO::AIO::poll_cb	1798	=item IO::AIO::poll_cb
1560		1799
1561	Process some outstanding events on the result pipe. You have to call	1800	Process some requests that have reached the result phase (i.e. they have
		1801	been executed but the results are not yet reported). You have to call
		1802	this "regularly" to finish outstanding requests.
		1803
1562	this regularly. Returns C<0> if all events could be processed (or there	1804	Returns C<0> if all events could be processed (or there were no
1563	were no events to process), or C<-1> if it returned earlier for whatever	1805	events to process), or C<-1> if it returned earlier for whatever
1564	reason. Returns immediately when no events are outstanding. The amount of	1806	reason. Returns immediately when no events are outstanding. The amount
1565	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1807	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1566	C<IO::AIO::max_poll_time>.	1808	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1567		1809
1568	If not all requests were processed for whatever reason, the filehandle	1810	If not all requests were processed for whatever reason, the poll file
1569	will still be ready when C<poll_cb> returns, so normally you don't have to	1811	descriptor will still be ready when C<poll_cb> returns, so normally you
1570	do anything special to have it called later.	1812	don't have to do anything special to have it called later.
1571		1813
1572	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1814	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1573	ready, it can be beneficial to call this function from loops which submit	1815	ready, it can be beneficial to call this function from loops which submit
1574	a lot of requests, to make sure the results get processed when they become	1816	a lot of requests, to make sure the results get processed when they become
1575	available and not just when the loop is finished and the event loop takes	1817	available and not just when the loop is finished and the event loop takes
…		…
1584	poll => 'r', async => 1,	1826	poll => 'r', async => 1,
1585	cb => \&IO::AIO::poll_cb);	1827	cb => \&IO::AIO::poll_cb);
1586		1828
1587	=item IO::AIO::poll_wait	1829	=item IO::AIO::poll_wait
1588		1830
1589	If there are any outstanding requests and none of them in the result	1831	Wait until either at least one request is in the result phase or no
1590	phase, wait till the result filehandle becomes ready for reading (simply	1832	requests are outstanding anymore.
1591	does a C<select> on the filehandle. This is useful if you want to	1833
1592	synchronously wait for some requests to finish).	1834	This is useful if you want to synchronously wait for some requests to
		1835	become ready, without actually handling them.
1593		1836
1594	See C<nreqs> for an example.	1837	See C<nreqs> for an example.
1595		1838
1596	=item IO::AIO::poll	1839	=item IO::AIO::poll
1597		1840
…		…
1718		1961
1719	This is a very bad function to use in interactive programs because it	1962	This is a very bad function to use in interactive programs because it
1720	blocks, and a bad way to reduce concurrency because it is inexact: Better	1963	blocks, and a bad way to reduce concurrency because it is inexact: Better
1721	use an C<aio_group> together with a feed callback.	1964	use an C<aio_group> together with a feed callback.
1722		1965
1723	It's main use is in scripts without an event loop - when you want to stat	1966	Its main use is in scripts without an event loop - when you want to stat
1724	a lot of files, you can write somehting like this:	1967	a lot of files, you can write something like this:
1725		1968
1726	IO::AIO::max_outstanding 32;	1969	IO::AIO::max_outstanding 32;
1727		1970
1728	for my $path (...) {	1971	for my $path (...) {
1729	aio_stat $path , ...;	1972	aio_stat $path , ...;
…		…
1768		2011
1769	=back	2012	=back
1770		2013
1771	=head3 MISCELLANEOUS FUNCTIONS	2014	=head3 MISCELLANEOUS FUNCTIONS
1772		2015
1773	IO::AIO implements some functions that might be useful, but are not	2016	IO::AIO implements some functions that are useful when you want to use
1774	asynchronous.	2017	some "Advanced I/O" function not available to in Perl, without going the
		2018	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2019	counterpart.
1775		2020
1776	=over 4	2021	=over 4
		2022
		2023	=item $numfd = IO::AIO::get_fdlimit
		2024
		2025	This function is I<EXPERIMENTAL> and subject to change.
		2026
		2027	Tries to find the current file descriptor limit and returns it, or
		2028	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2029	the highest valid file descriptor number.
		2030
		2031	=item IO::AIO::min_fdlimit [$numfd]
		2032
		2033	This function is I<EXPERIMENTAL> and subject to change.
		2034
		2035	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2036	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2037	is missing, it will try to set a very high limit, although this is not
		2038	recommended when you know the actual minimum that you require.
		2039
		2040	If the limit cannot be raised enough, the function makes a best-effort
		2041	attempt to increase the limit as much as possible, using various
		2042	tricks, while still failing. You can query the resulting limit using
		2043	C<IO::AIO::get_fdlimit>.
		2044
		2045	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2046	true.
1777		2047
1778	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2048	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1779		2049
1780	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2050	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1781	but is blocking (this makes most sense if you know the input data is	2051	but is blocking (this makes most sense if you know the input data is
…		…
1798	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2068	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1799		2069
1800	Simply calls the C<posix_madvise> function (see its	2070	Simply calls the C<posix_madvise> function (see its
1801	manpage for details). The following advice constants are	2071	manpage for details). The following advice constants are
1802	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2072	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1803	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2073	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2074	C<IO::AIO::MADV_DONTNEED>.
		2075
		2076	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2077	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2078	will be reduced to fit into the C<$scalar>.
1804		2079
1805	On systems that do not implement C<posix_madvise>, this function returns	2080	On systems that do not implement C<posix_madvise>, this function returns
1806	ENOSYS, otherwise the return value of C<posix_madvise>.	2081	ENOSYS, otherwise the return value of C<posix_madvise>.
1807		2082
1808	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2083	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1810	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2085	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1811	$scalar (see its manpage for details). The following protect	2086	$scalar (see its manpage for details). The following protect
1812	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2087	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1813	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2088	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1814		2089
		2090	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2091	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2092	will be reduced to fit into the C<$scalar>.
		2093
1815	On systems that do not implement C<mprotect>, this function returns	2094	On systems that do not implement C<mprotect>, this function returns
1816	ENOSYS, otherwise the return value of C<mprotect>.	2095	ENOSYS, otherwise the return value of C<mprotect>.
1817		2096
1818	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2097	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1819		2098
1820	Memory-maps a file (or anonymous memory range) and attaches it to the	2099	Memory-maps a file (or anonymous memory range) and attaches it to the
1821	given C<$scalar>, which will act like a string scalar.	2100	given C<$scalar>, which will act like a string scalar. Returns true on
		2101	success, and false otherwise.
1822		2102
		2103	The scalar must exist, but its contents do not matter - this means you
		2104	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2105	the scalar first.
		2106
1823	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2107	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1824	change the string length, and most read-only operations such as copying it	2108	which don't change the string length, and most read-only operations such
1825	or searching it with regexes and so on.	2109	as copying it or searching it with regexes and so on.
1826		2110
1827	Anything else is unsafe and will, at best, result in memory leaks.	2111	Anything else is unsafe and will, at best, result in memory leaks.
1828		2112
1829	The memory map associated with the C<$scalar> is automatically removed	2113	The memory map associated with the C<$scalar> is automatically removed
1830	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2114	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1831	C<IO::AIO::munmap> functions are called.	2115	or C<IO::AIO::munmap> functions are called on it.
1832		2116
1833	This calls the C<mmap>(2) function internally. See your system's manual	2117	This calls the C<mmap>(2) function internally. See your system's manual
1834	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2118	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1835		2119
1836	The C<$length> must be larger than zero and smaller than the actual	2120	The C<$length> must be larger than zero and smaller than the actual
1837	filesize.	2121	filesize.
1838		2122
1839	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2123	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1840	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2124	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1841		2125
1842	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2126	C<$flags> can be a combination of
1843	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2127	C<IO::AIO::MAP_SHARED> or
1844	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2128	C<IO::AIO::MAP_PRIVATE>,
		2129	or a number of system-specific flags (when not available, the are C<0>):
1845	(which is set to C<MAP_ANON> if your system only provides this	2130	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1846	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2131	C<IO::AIO::MAP_LOCKED>,
1847	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2132	C<IO::AIO::MAP_NORESERVE>,
		2133	C<IO::AIO::MAP_POPULATE>,
1848	C<IO::AIO::MAP_NONBLOCK>	2134	C<IO::AIO::MAP_NONBLOCK>,
		2135	C<IO::AIO::MAP_FIXED>,
		2136	C<IO::AIO::MAP_GROWSDOWN>,
		2137	C<IO::AIO::MAP_32BIT>,
		2138	C<IO::AIO::MAP_HUGETLB> or
		2139	C<IO::AIO::MAP_STACK>.
1849		2140
1850	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2141	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1851		2142
1852	C<$offset> is the offset from the start of the file - it generally must be	2143	C<$offset> is the offset from the start of the file - it generally must be
1853	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2144	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1878		2169
1879	Calls the C<munlockall> function.	2170	Calls the C<munlockall> function.
1880		2171
1881	On systems that do not implement C<munlockall>, this function returns	2172	On systems that do not implement C<munlockall>, this function returns
1882	ENOSYS, otherwise the return value of C<munlockall>.	2173	ENOSYS, otherwise the return value of C<munlockall>.
		2174
		2175	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2176
		2177	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2178	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2179	should be the file offset.
		2180
		2181	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2182	silently corrupt the data in this case.
		2183
		2184	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2185	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2186	C<IO::AIO::SPLICE_F_GIFT>.
		2187
		2188	See the C<splice(2)> manpage for details.
		2189
		2190	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2191
		2192	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2193	description for C<IO::AIO::splice> above for details.
		2194
		2195	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2196
		2197	Attempts to query or change the pipe buffer size. Obviously works only
		2198	on pipes, and currently works only on GNU/Linux systems, and fails with
		2199	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2200	size on other systems, drop me a note.
		2201
		2202	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2203
		2204	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2205	C<$flags> is missing or C<0>, then this should be the same as a call to
		2206	perl's built-in C<pipe> function and create a new pipe, and works on
		2207	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2208	(..., 4096, O_BINARY)>.
		2209
		2210	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2211	the given flags (Linux 2.6.27, glibc 2.9).
		2212
		2213	On success, the read and write file handles are returned.
		2214
		2215	On error, nothing will be returned. If the pipe2 syscall is missing and
		2216	C<$flags> is non-zero, fails with C<ENOSYS>.
		2217
		2218	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2219	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2220	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2221
		2222	Example: create a pipe race-free w.r.t. threads and fork:
		2223
		2224	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2225	or die "pipe2: $!\n";
		2226
		2227	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2228
		2229	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2230	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2231
		2232	On success, the new eventfd filehandle is returned, otherwise returns
		2233	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2234
		2235	Please refer to L<eventfd(2)> for more info on this call.
		2236
		2237	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2238	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2239
		2240	Example: create a new eventfd filehandle:
		2241
		2242	$fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
		2243	or die "eventfd: $!\n";
		2244
		2245	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2246
		2247	This is a direct interface to the Linux L<timerfd_create(2)> system call. The
		2248	(unhelpful) default for C<$flags> is C<0>.
		2249
		2250	On success, the new timerfd filehandle is returned, otherwise returns
		2251	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2252
		2253	Please refer to L<timerfd_create(2)> for more info on this call.
		2254
		2255	The following C<$clockid> values are
		2256	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2257	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2258	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2259	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2260
		2261	The following C<$flags> values are available (Linux
		2262	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2263
		2264	Example: create a new timerfd and set it to one-second repeated alarms,
		2265	then wait for two alarms:
		2266
		2267	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2268	or die "timerfd_create: $!\n";
		2269
		2270	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2271	or die "timerfd_settime: $!\n";
		2272
		2273	for (1..2) {
		2274	8 == sysread $fh, my $buf, 8
		2275	or die "timerfd read failure\n";
		2276
		2277	printf "number of expirations (likely 1): %d\n",
		2278	unpack "Q", $buf;
		2279	}
		2280
		2281	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2282
		2283	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2284	call. Please refer to its manpage for more info on this call.
		2285
		2286	The new itimerspec is specified using two (possibly fractional) second
		2287	values, C<$new_interval> and C<$new_value>).
		2288
		2289	On success, the current interval and value are returned (as per
		2290	C<timerfd_gettime>). On failure, the empty list is returned.
		2291
		2292	The following C<$flags> values are
		2293	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2294	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2295
		2296	See C<IO::AIO::timerfd_create> for a full example.
		2297
		2298	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2299
		2300	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2301	call. Please refer to its manpage for more info on this call.
		2302
		2303	On success, returns the current values of interval and value for the given
		2304	timerfd (as potentially fractional second values). On failure, the empty
		2305	list is returned.
1883		2306
1884	=back	2307	=back
1885		2308
1886	=cut	2309	=cut
1887		2310
…		…
1953	the process will result in undefined behaviour. Calling it at any time	2376	the process will result in undefined behaviour. Calling it at any time
1954	will also result in any undefined (by POSIX) behaviour.	2377	will also result in any undefined (by POSIX) behaviour.
1955		2378
1956	=back	2379	=back
1957		2380
		2381	=head2 LINUX-SPECIFIC CALLS
		2382
		2383	When a call is documented as "linux-specific" then this means it
		2384	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2385	availability and compatibility of such calls regardless of the platform
		2386	it is compiled on, so platforms such as FreeBSD which often implement
		2387	these calls will work. When in doubt, call them and see if they fail wth
		2388	C<ENOSYS>.
		2389
1958	=head2 MEMORY USAGE	2390	=head2 MEMORY USAGE
1959		2391
1960	Per-request usage:	2392	Per-request usage:
1961		2393
1962	Each aio request uses - depending on your architecture - around 100-200	2394	Each aio request uses - depending on your architecture - around 100-200
…		…
1974	temporary buffers, and each thread requires a stack and other data	2406	temporary buffers, and each thread requires a stack and other data
1975	structures (usually around 16k-128k, depending on the OS).	2407	structures (usually around 16k-128k, depending on the OS).
1976		2408
1977	=head1 KNOWN BUGS	2409	=head1 KNOWN BUGS
1978		2410
1979	Known bugs will be fixed in the next release.	2411	Known bugs will be fixed in the next release :)
		2412
		2413	=head1 KNOWN ISSUES
		2414
		2415	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2416	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2417	non-created hash slots or other scalars I didn't think of. It's best to
		2418	avoid such and either use scalar variables or making sure that the scalar
		2419	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2420
		2421	I am not sure anything can be done about this, so this is considered a
		2422	known issue, rather than a bug.
1980		2423
1981	=head1 SEE ALSO	2424	=head1 SEE ALSO
1982		2425
1983	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2426	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1984	more natural syntax.	2427	more natural syntax.

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC vs. Revision 1.284 by root, Fri Mar 23 01:14:08 2018 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC vs.
Revision 1.284 by root, Fri Mar 23 01:14:08 2018 UTC