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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.254 by root, Thu Jun 25 13:42:18 2015 UTC vs.
Revision 1.319 by root, Wed Sep 27 03:09:57 2023 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
…		…
94		98
95	# file contents now in $contents	99	# file contents now in $contents
96	print $contents;	100	print $contents;
97		101
98	# exit event loop and program	102	# exit event loop and program
99	EV::unloop;	103	EV::break;
100	};	104	};
101	};	105	};
102		106
103	# possibly queue up other requests, or open GUI windows,	107	# possibly queue up other requests, or open GUI windows,
104	# check for sockets etc. etc.	108	# check for sockets etc. etc.
105		109
106	# process events as long as there are some:	110	# process events as long as there are some:
107	EV::loop;	111	EV::run;
108		112
109	=head1 REQUEST ANATOMY AND LIFETIME	113	=head1 REQUEST ANATOMY AND LIFETIME
110		114
111	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
112	directly visible to Perl.	116	directly visible to Perl.
…		…
167	use common::sense;	171	use common::sense;
168		172
169	use base 'Exporter';	173	use base 'Exporter';
170		174
171	BEGIN {	175	BEGIN {
172	our $VERSION = 4.32;	176	our $VERSION = 4.80;
173		177
174	our @AIO_REQ = qw(aio_sendfile aio_seek 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
175	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
176	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
177	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
178	aio_pathsync aio_readahead aio_fiemap	182	aio_pathsync aio_readahead aio_fiemap aio_allocate
179	aio_rename aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
183	aio_statvfs	187	aio_statvfs
		188	aio_slurp
184	aio_wd);	189	aio_wd);
185		190
186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	191	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	192	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
188	min_parallel max_parallel max_idle idle_timeout	193	min_parallel max_parallel max_idle idle_timeout
189	nreqs nready npending nthreads	194	nreqs nready npending nthreads
190	max_poll_time max_poll_reqs	195	max_poll_time max_poll_reqs
191	sendfile fadvise madvise	196	sendfile fadvise madvise
192	mmap munmap munlock munlockall);	197	mmap munmap mremap munlock munlockall
		198
		199	accept4 tee splice pipe2 pipesize
		200	fexecve mount umount memfd_create eventfd
		201	timerfd_create timerfd_settime timerfd_gettime
		202	pidfd_open pidfd_send_signal pidfd_getfd);
193		203
194	push @AIO_REQ, qw(aio_busy); # not exported	204	push @AIO_REQ, qw(aio_busy); # not exported
195		205
196	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	206	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
197		207
…		…
229	aio_link $srcpath, $dstpath, $callback->($status)	239	aio_link $srcpath, $dstpath, $callback->($status)
230	aio_symlink $srcpath, $dstpath, $callback->($status)	240	aio_symlink $srcpath, $dstpath, $callback->($status)
231	aio_readlink $pathname, $callback->($link)	241	aio_readlink $pathname, $callback->($link)
232	aio_realpath $pathname, $callback->($path)	242	aio_realpath $pathname, $callback->($path)
233	aio_rename $srcpath, $dstpath, $callback->($status)	243	aio_rename $srcpath, $dstpath, $callback->($status)
		244	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
234	aio_mkdir $pathname, $mode, $callback->($status)	245	aio_mkdir $pathname, $mode, $callback->($status)
235	aio_rmdir $pathname, $callback->($status)	246	aio_rmdir $pathname, $callback->($status)
236	aio_readdir $pathname, $callback->($entries)	247	aio_readdir $pathname, $callback->($entries)
237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	248	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	249	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
…		…
240	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	251	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
241	aio_load $pathname, $data, $callback->($status)	252	aio_load $pathname, $data, $callback->($status)
242	aio_copy $srcpath, $dstpath, $callback->($status)	253	aio_copy $srcpath, $dstpath, $callback->($status)
243	aio_move $srcpath, $dstpath, $callback->($status)	254	aio_move $srcpath, $dstpath, $callback->($status)
244	aio_rmtree $pathname, $callback->($status)	255	aio_rmtree $pathname, $callback->($status)
		256	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		257	aio_ioctl $fh, $request, $buf, $callback->($status)
245	aio_sync $callback->($status)	258	aio_sync $callback->($status)
246	aio_syncfs $fh, $callback->($status)	259	aio_syncfs $fh, $callback->($status)
247	aio_fsync $fh, $callback->($status)	260	aio_fsync $fh, $callback->($status)
248	aio_fdatasync $fh, $callback->($status)	261	aio_fdatasync $fh, $callback->($status)
249	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	262	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
250	aio_pathsync $pathname, $callback->($status)	263	aio_pathsync $pathname, $callback->($status)
251	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	264	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
252	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	265	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
253	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	266	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
254	aio_mlockall $flags, $callback->($status)	267	aio_mlockall $flags, $callback->($status)
255	aio_group $callback->(...)	268	aio_group $callback->(...)
256	aio_nop $callback->()	269	aio_nop $callback->()
…		…
270	IO::AIO::idle_timeout $seconds	283	IO::AIO::idle_timeout $seconds
271	IO::AIO::max_outstanding $maxreqs	284	IO::AIO::max_outstanding $maxreqs
272	IO::AIO::nreqs	285	IO::AIO::nreqs
273	IO::AIO::nready	286	IO::AIO::nready
274	IO::AIO::npending	287	IO::AIO::npending
		288	IO::AIO::reinit
		289
		290	$nfd = IO::AIO::get_fdlimit
		291	IO::AIO::min_fdlimit $nfd
275		292
276	IO::AIO::sendfile $ofh, $ifh, $offset, $count	293	IO::AIO::sendfile $ofh, $ifh, $offset, $count
277	IO::AIO::fadvise $fh, $offset, $len, $advice	294	IO::AIO::fadvise $fh, $offset, $len, $advice
		295	IO::AIO::fexecve $fh, $argv, $envp
		296
278	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]	297	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
279	IO::AIO::munmap $scalar	298	IO::AIO::munmap $scalar
		299	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
280	IO::AIO::madvise $scalar, $offset, $length, $advice	300	IO::AIO::madvise $scalar, $offset, $length, $advice
281	IO::AIO::mprotect $scalar, $offset, $length, $protect	301	IO::AIO::mprotect $scalar, $offset, $length, $protect
282	IO::AIO::munlock $scalar, $offset = 0, $length = undef	302	IO::AIO::munlock $scalar, $offset = 0, $length = undef
283	IO::AIO::munlockall	303	IO::AIO::munlockall
		304
		305	# stat extensions
		306	$counter = IO::AIO::st_gen
		307	$seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		308	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		309	$nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		310	$seconds = IO::AIO::st_btimesec
		311	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		312
		313	# very much unportable syscalls
		314	IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
		315	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		316	IO::AIO::tee $r_fh, $w_fh, $length, $flags
		317
		318	$actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		319	($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		320
		321	$fh = IO::AIO::eventfd [$initval, [$flags]]
		322	$fh = IO::AIO::memfd_create $pathname[, $flags]
		323
		324	$fh = IO::AIO::timerfd_create $clockid[, $flags]
		325	($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		326	($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		327
		328	$fh = IO::AIO::pidfd_open $pid[, $flags]
		329	$status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
		330	$fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
		331
		332	$retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data = undef
		333	$retval = IO::AIO::umount $path, $flags = 0
284		334
285	=head2 API NOTES	335	=head2 API NOTES
286		336
287	All the C<aio_*> calls are more or less thin wrappers around the syscall	337	All the C<aio_*> calls are more or less thin wrappers around the syscall
288	with the same name (sans C<aio_>). The arguments are similar or identical,	338	with the same name (sans C<aio_>). The arguments are similar or identical,
…		…
363	=item aio_open $pathname, $flags, $mode, $callback->($fh)	413	=item aio_open $pathname, $flags, $mode, $callback->($fh)
364		414
365	Asynchronously open or create a file and call the callback with a newly	415	Asynchronously open or create a file and call the callback with a newly
366	created filehandle for the file (or C<undef> in case of an error).	416	created filehandle for the file (or C<undef> in case of an error).
367		417
368	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
369	for an explanation.
370
371	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	418	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
372	list. They are the same as used by C<sysopen>.	419	list. They are the same as used by C<sysopen>.
373		420
374	Likewise, C<$mode> specifies the mode of the newly created file, if it	421	Likewise, C<$mode> specifies the mode of the newly created file, if it
375	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	422	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
…		…
394	following POSIX and non-POSIX constants are available (missing ones on	441	following POSIX and non-POSIX constants are available (missing ones on
395	your system are, as usual, C<0>):	442	your system are, as usual, C<0>):
396		443
397	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	444	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
398	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	445	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
399	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	446	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
400		447
401		448
402	=item aio_close $fh, $callback->($status)	449	=item aio_close $fh, $callback->($status)
403		450
404	Asynchronously close a file and call the callback with the result	451	Asynchronously close a file and call the callback with the result
…		…
439	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	486	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
440		487
441	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	488	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
442		489
443	Reads or writes C<$length> bytes from or to the specified C<$fh> and	490	Reads or writes C<$length> bytes from or to the specified C<$fh> and
444	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	491	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
445	and calls the callback without the actual number of bytes read (or -1 on	492	calls the callback with the actual number of bytes transferred (or -1 on
446	error, just like the syscall).	493	error, just like the syscall).
447		494
448	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	495	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
449	offset plus the actual number of bytes read.	496	offset plus the actual number of bytes read.
450		497
…		…
508	As native sendfile syscalls (as practically any non-POSIX interface hacked	555	As native sendfile syscalls (as practically any non-POSIX interface hacked
509	together in a hurry to improve benchmark numbers) tend to be rather buggy	556	together in a hurry to improve benchmark numbers) tend to be rather buggy
510	on many systems, this implementation tries to work around some known bugs	557	on many systems, this implementation tries to work around some known bugs
511	in Linux and FreeBSD kernels (probably others, too), but that might fail,	558	in Linux and FreeBSD kernels (probably others, too), but that might fail,
512	so you really really should check the return value of C<aio_sendfile> -	559	so you really really should check the return value of C<aio_sendfile> -
513	fewre bytes than expected might have been transferred.	560	fewer bytes than expected might have been transferred.
514		561
515		562
516	=item aio_readahead $fh,$offset,$length, $callback->($retval)	563	=item aio_readahead $fh,$offset,$length, $callback->($retval)
517		564
518	C<aio_readahead> populates the page cache with data from a file so that	565	C<aio_readahead> populates the page cache with data from a file so that
…		…
522	whole pages, so that offset is effectively rounded down to a page boundary	569	whole pages, so that offset is effectively rounded down to a page boundary
523	and bytes are read up to the next page boundary greater than or equal to	570	and bytes are read up to the next page boundary greater than or equal to
524	(off-set+length). C<aio_readahead> does not read beyond the end of the	571	(off-set+length). C<aio_readahead> does not read beyond the end of the
525	file. The current file offset of the file is left unchanged.	572	file. The current file offset of the file is left unchanged.
526		573
527	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	574	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
528	emulated by simply reading the data, which would have a similar effect.	575	be emulated by simply reading the data, which would have a similar effect.
529		576
530		577
531	=item aio_stat $fh_or_path, $callback->($status)	578	=item aio_stat $fh_or_path, $callback->($status)
532		579
533	=item aio_lstat $fh, $callback->($status)	580	=item aio_lstat $fh, $callback->($status)
534		581
535	Works like perl's C<stat> or C<lstat> in void context. The callback will	582	Works almost exactly like perl's C<stat> or C<lstat> in void context. The
536	be called after the stat and the results will be available using C<stat _>	583	callback will be called after the stat and the results will be available
537	or C<-s _> etc...	584	using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
538		585	and C<-T>).
539	The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
540	for an explanation.
541		586
542	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	587	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
543	error when stat'ing a large file, the results will be silently truncated	588	error when stat'ing a large file, the results will be silently truncated
544	unless perl itself is compiled with large file support.	589	unless perl itself is compiled with large file support.
545		590
…		…
549	behaviour).	594	behaviour).
550		595
551	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,	596	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
552	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,	597	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
553	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.	598	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		599
		600	To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
		601	ACCESS>.
554		602
555	Example: Print the length of F</etc/passwd>:	603	Example: Print the length of F</etc/passwd>:
556		604
557	aio_stat "/etc/passwd", sub {	605	aio_stat "/etc/passwd", sub {
558	$_[0] and die "stat failed: $!";	606	$_[0] and die "stat failed: $!";
…		…
602	namemax => 255,	650	namemax => 255,
603	frsize => 1024,	651	frsize => 1024,
604	fsid => 1810	652	fsid => 1810
605	}	653	}
606		654
607	Here is a (likely partial - send me updates!) list of fsid values used by
608	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
609
610	0x0000adf5 adfs
611	0x0000adff affs
612	0x5346414f afs
613	0x09041934 anon-inode filesystem
614	0x00000187 autofs
615	0x42465331 befs
616	0x1badface bfs
617	0x42494e4d binfmt_misc
618	0x9123683e btrfs
619	0x0027e0eb cgroupfs
620	0xff534d42 cifs
621	0x73757245 coda
622	0x012ff7b7 coh
623	0x28cd3d45 cramfs
624	0x453dcd28 cramfs-wend (wrong endianness)
625	0x64626720 debugfs
626	0x00001373 devfs
627	0x00001cd1 devpts
628	0x0000f15f ecryptfs
629	0x00414a53 efs
630	0x0000137d ext
631	0x0000ef53 ext2/ext3
632	0x0000ef51 ext2
633	0x00004006 fat
634	0x65735546 fuseblk
635	0x65735543 fusectl
636	0x0bad1dea futexfs
637	0x01161970 gfs2
638	0x47504653 gpfs
639	0x00004244 hfs
640	0xf995e849 hpfs
641	0x958458f6 hugetlbfs
642	0x2bad1dea inotifyfs
643	0x00009660 isofs
644	0x000072b6 jffs2
645	0x3153464a jfs
646	0x6b414653 k-afs
647	0x0bd00bd0 lustre
648	0x0000137f minix
649	0x0000138f minix 30 char names
650	0x00002468 minix v2
651	0x00002478 minix v2 30 char names
652	0x00004d5a minix v3
653	0x19800202 mqueue
654	0x00004d44 msdos
655	0x0000564c novell
656	0x00006969 nfs
657	0x6e667364 nfsd
658	0x00003434 nilfs
659	0x5346544e ntfs
660	0x00009fa1 openprom
661	0x7461636F ocfs2
662	0x00009fa0 proc
663	0x6165676c pstorefs
664	0x0000002f qnx4
665	0x858458f6 ramfs
666	0x52654973 reiserfs
667	0x00007275 romfs
668	0x67596969 rpc_pipefs
669	0x73636673 securityfs
670	0xf97cff8c selinux
671	0x0000517b smb
672	0x534f434b sockfs
673	0x73717368 squashfs
674	0x62656572 sysfs
675	0x012ff7b6 sysv2
676	0x012ff7b5 sysv4
677	0x01021994 tmpfs
678	0x15013346 udf
679	0x00011954 ufs
680	0x54190100 ufs byteswapped
681	0x00009fa2 usbdevfs
682	0x01021997 v9fs
683	0xa501fcf5 vxfs
684	0xabba1974 xenfs
685	0x012ff7b4 xenix
686	0x58465342 xfs
687	0x012fd16d xia
688
689	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	655	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
690		656
691	Works like perl's C<utime> function (including the special case of $atime	657	Works like perl's C<utime> function (including the special case of $atime
692	and $mtime being undef). Fractional times are supported if the underlying	658	and $mtime being undef). Fractional times are supported if the underlying
693	syscalls support them.	659	syscalls support them.
694		660
695	When called with a pathname, uses utimes(2) if available, otherwise	661	When called with a pathname, uses utimensat(2) or utimes(2) if available,
696	utime(2). If called on a file descriptor, uses futimes(2) if available,	662	otherwise utime(2). If called on a file descriptor, uses futimens(2)
697	otherwise returns ENOSYS, so this is not portable.	663	or futimes(2) if available, otherwise returns ENOSYS, so this is not
		664	portable.
698		665
699	Examples:	666	Examples:
700		667
701	# set atime and mtime to current time (basically touch(1)):	668	# set atime and mtime to current time (basically touch(1)):
702	aio_utime "path", undef, undef;	669	aio_utime "path", undef, undef;
…		…
730	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate	697	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
731	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,	698	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
732	to deallocate a file range.	699	to deallocate a file range.
733		700
734	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range	701	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
735	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see	702	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
736	your L<fallocate(2)> manpage).	703	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		704	to unshare shared blocks (see your L<fallocate(2)> manpage).
737		705
738	The file system block size used by C<fallocate> is presumably the	706	The file system block size used by C<fallocate> is presumably the
739	C<f_bsize> returned by C<statvfs>.	707	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		708	can dictate other limitations.
740		709
741	If C<fallocate> isn't available or cannot be emulated (currently no	710	If C<fallocate> isn't available or cannot be emulated (currently no
742	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.	711	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
743		712
744		713
…		…
803	On systems that support the AIO::WD working directory abstraction	772	On systems that support the AIO::WD working directory abstraction
804	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead	773	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
805	of failing, C<rename> is called on the absolute path of C<$wd>.	774	of failing, C<rename> is called on the absolute path of C<$wd>.
806		775
807		776
		777	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		778
		779	Basically a version of C<aio_rename> with an additional C<$flags>
		780	argument. Calling this with C<$flags=0> is the same as calling
		781	C<aio_rename>.
		782
		783	Non-zero flags are currently only supported on GNU/Linux systems that
		784	support renameat2. Other systems fail with C<ENOSYS> in this case.
		785
		786	The following constants are available (missing ones are, as usual C<0>),
		787	see renameat2(2) for details:
		788
		789	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		790	and C<IO::AIO::RENAME_WHITEOUT>.
		791
		792
808	=item aio_mkdir $pathname, $mode, $callback->($status)	793	=item aio_mkdir $pathname, $mode, $callback->($status)
809		794
810	Asynchronously mkdir (create) a directory and call the callback with	795	Asynchronously mkdir (create) a directory and call the callback with
811	the result code. C<$mode> will be modified by the umask at the time the	796	the result code. C<$mode> will be modified by the umask at the time the
812	request is executed, so do not change your umask.	797	request is executed, so do not change your umask.
…		…
843		828
844	=over 4	829	=over 4
845		830
846	=item IO::AIO::READDIR_DENTS	831	=item IO::AIO::READDIR_DENTS
847		832
848	When this flag is off, then the callback gets an arrayref consisting of	833	Normally the callback gets an arrayref consisting of names only (as
849	names only (as with C<aio_readdir>), otherwise it gets an arrayref with	834	with C<aio_readdir>). If this flag is set, then the callback gets an
850	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	835	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
851	entry in more detail.	836	single directory entry in more detail:
852		837
853	C<$name> is the name of the entry.	838	C<$name> is the name of the entry.
854		839
855	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	840	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
856		841
857	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	842	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
858	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	843	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
859	C<IO::AIO::DT_WHT>.	844	C<IO::AIO::DT_WHT>.
860		845
861	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	846	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
862	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	847	to know, you have to run stat yourself. Also, for speed/memory reasons,
863	scalars are read-only: you can not modify them.	848	the C<$type> scalars are read-only: you must not modify them.
864		849
865	C<$inode> is the inode number (which might not be exact on systems with 64	850	C<$inode> is the inode number (which might not be exact on systems with 64
866	bit inode numbers and 32 bit perls). This field has unspecified content on	851	bit inode numbers and 32 bit perls). This field has unspecified content on
867	systems that do not deliver the inode information.	852	systems that do not deliver the inode information.
868		853
…		…
879	short names are tried first.	864	short names are tried first.
880		865
881	=item IO::AIO::READDIR_STAT_ORDER	866	=item IO::AIO::READDIR_STAT_ORDER
882		867
883	When this flag is set, then the names will be returned in an order	868	When this flag is set, then the names will be returned in an order
884	suitable for stat()'ing each one. That is, when you plan to stat()	869	suitable for stat()'ing each one. That is, when you plan to stat() most or
885	all files in the given directory, then the returned order will likely	870	all files in the given directory, then the returned order will likely be
886	be fastest.	871	faster.
887		872
888	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	873	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
889	the likely dirs come first, resulting in a less optimal stat order.	874	then the likely dirs come first, resulting in a less optimal stat order
		875	for stat'ing all entries, but likely a more optimal order for finding
		876	subdirectories.
890		877
891	=item IO::AIO::READDIR_FOUND_UNKNOWN	878	=item IO::AIO::READDIR_FOUND_UNKNOWN
892		879
893	This flag should not be set when calling C<aio_readdirx>. Instead, it	880	This flag should not be set when calling C<aio_readdirx>. Instead, it
894	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	881	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
896	C<$type>'s are known, which can be used to speed up some algorithms.	883	C<$type>'s are known, which can be used to speed up some algorithms.
897		884
898	=back	885	=back
899		886
900		887
		888	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		889
		890	Opens, reads and closes the given file. The data is put into C<$data>,
		891	which is resized as required.
		892
		893	If C<$offset> is negative, then it is counted from the end of the file.
		894
		895	If C<$length> is zero, then the remaining length of the file is
		896	used. Also, in this case, the same limitations to modifying C<$data> apply
		897	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		898	with C<substr>. If the size of the file is known, specifying a non-zero
		899	C<$length> results in a performance advantage.
		900
		901	This request is similar to the older C<aio_load> request, but since it is
		902	a single request, it might be more efficient to use.
		903
		904	Example: load F</etc/passwd> into C<$passwd>.
		905
		906	my $passwd;
		907	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		908	$_[0] >= 0
		909	or die "/etc/passwd: $!\n";
		910
		911	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		912	print $passwd;
		913	};
		914	IO::AIO::flush;
		915
		916
901	=item aio_load $pathname, $data, $callback->($status)	917	=item aio_load $pathname, $data, $callback->($status)
902		918
903	This is a composite request that tries to fully load the given file into	919	This is a composite request that tries to fully load the given file into
904	memory. Status is the same as with aio_read.	920	memory. Status is the same as with aio_read.
		921
		922	Using C<aio_slurp> might be more efficient, as it is a single request.
905		923
906	=cut	924	=cut
907		925
908	sub aio_load($$;$) {	926	sub aio_load($$;$) {
909	my ($path, undef, $cb) = @_;	927	my ($path, undef, $cb) = @_;
…		…
930		948
931	Try to copy the I<file> (directories not supported as either source or	949	Try to copy the I<file> (directories not supported as either source or
932	destination) from C<$srcpath> to C<$dstpath> and call the callback with	950	destination) from C<$srcpath> to C<$dstpath> and call the callback with
933	a status of C<0> (ok) or C<-1> (error, see C<$!>).	951	a status of C<0> (ok) or C<-1> (error, see C<$!>).
934		952
		953	Existing destination files will be truncated.
		954
935	This is a composite request that creates the destination file with	955	This is a composite request that creates the destination file with
936	mode 0200 and copies the contents of the source file into it using	956	mode 0200 and copies the contents of the source file into it using
937	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	957	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
938	uid/gid, in that order.	958	uid/gid, in that order.
939		959
…		…
955	my @stat = stat $src_fh; # hmm, might block over nfs?	975	my @stat = stat $src_fh; # hmm, might block over nfs?
956		976
957	aioreq_pri $pri;	977	aioreq_pri $pri;
958	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	978	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
959	if (my $dst_fh = $_[0]) {	979	if (my $dst_fh = $_[0]) {
		980
		981	# best-effort preallocate
		982	aioreq_pri $pri;
		983	add $grp aio_allocate $dst_fh, IO::AIO::FALLOC_FL_KEEP_SIZE, 0, $stat[7], sub { };
		984
960	aioreq_pri $pri;	985	aioreq_pri $pri;
961	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	986	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
962	if ($_[0] == $stat[7]) {	987	if ($_[0] == $stat[7]) {
963	$grp->result (0);	988	$grp->result (0);
964	close $src_fh;	989	close $src_fh;
…		…
1048	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1073	Scans a directory (similar to C<aio_readdir>) but additionally tries to
1049	efficiently separate the entries of directory C<$path> into two sets of	1074	efficiently separate the entries of directory C<$path> into two sets of
1050	names, directories you can recurse into (directories), and ones you cannot	1075	names, directories you can recurse into (directories), and ones you cannot
1051	recurse into (everything else, including symlinks to directories).	1076	recurse into (everything else, including symlinks to directories).
1052		1077
1053	C<aio_scandir> is a composite request that creates of many sub requests_	1078	C<aio_scandir> is a composite request that generates many sub requests.
1054	C<$maxreq> specifies the maximum number of outstanding aio requests that	1079	C<$maxreq> specifies the maximum number of outstanding aio requests that
1055	this function generates. If it is C<< <= 0 >>, then a suitable default	1080	this function generates. If it is C<< <= 0 >>, then a suitable default
1056	will be chosen (currently 4).	1081	will be chosen (currently 4).
1057		1082
1058	On error, the callback is called without arguments, otherwise it receives	1083	On error, the callback is called without arguments, otherwise it receives
…		…
1122	aioreq_pri $pri;	1147	aioreq_pri $pri;
1123	add $grp aio_stat $wd, sub {	1148	add $grp aio_stat $wd, sub {
1124	return $grp->result () if $_[0];	1149	return $grp->result () if $_[0];
1125	my $now = time;	1150	my $now = time;
1126	my $hash1 = join ":", (stat _)[0,1,3,7,9];	1151	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		1152	my $rdxflags = READDIR_DIRS_FIRST;
		1153
		1154	if ((stat _)[3] < 2) {
		1155	# at least one non-POSIX filesystem exists
		1156	# that returns useful DT_type values: btrfs,
		1157	# so optimise for this here by requesting dents
		1158	$rdxflags \|= READDIR_DENTS;
		1159	}
1127		1160
1128	# read the directory entries	1161	# read the directory entries
1129	aioreq_pri $pri;	1162	aioreq_pri $pri;
1130	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {	1163	add $grp aio_readdirx $wd, $rdxflags, sub {
1131	my $entries = shift	1164	my ($entries, $flags) = @_
1132	or return $grp->result ();	1165	or return $grp->result ();
		1166
		1167	if ($rdxflags & READDIR_DENTS) {
		1168	# if we requested type values, see if we can use them directly.
		1169
		1170	# if there were any DT_UNKNOWN entries then we assume we
		1171	# don't know. alternatively, we could assume that if we get
		1172	# one DT_DIR, then all directories are indeed marked with
		1173	# DT_DIR, but this seems not required for btrfs, and this
		1174	# is basically the "btrfs can't get it's act together" code
		1175	# branch.
		1176	unless ($flags & READDIR_FOUND_UNKNOWN) {
		1177	# now we have valid DT_ information for all entries,
		1178	# so use it as an optimisation without further stat's.
		1179	# they must also all be at the beginning of @$entries
		1180	# by now.
		1181
		1182	my $dirs;
		1183
		1184	if (@$entries) {
		1185	for (0 .. $#$entries) {
		1186	if ($entries->[$_][1] != DT_DIR) {
		1187	# splice out directories
		1188	$dirs = [splice @$entries, 0, $_];
		1189	last;
		1190	}
		1191	}
		1192
		1193	# if we didn't find any non-dir, then all entries are dirs
		1194	unless ($dirs) {
		1195	($dirs, $entries) = ($entries, []);
		1196	}
		1197	} else {
		1198	# directory is empty, so there are no sbdirs
		1199	$dirs = [];
		1200	}
		1201
		1202	# either splice'd the directories out or the dir was empty.
		1203	# convert dents to filenames
		1204	$_ = $_->[0] for @$dirs;
		1205	$_ = $_->[0] for @$entries;
		1206
		1207	return $grp->result ($dirs, $entries);
		1208	}
		1209
		1210	# cannot use, so return to our old ways
		1211	# by pretending we only scanned for names.
		1212	$_ = $_->[0] for @$entries;
		1213	}
1133		1214
1134	# stat the dir another time	1215	# stat the dir another time
1135	aioreq_pri $pri;	1216	aioreq_pri $pri;
1136	add $grp aio_stat $wd, sub {	1217	add $grp aio_stat $wd, sub {
1137	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1218	my $hash2 = join ":", (stat _)[0,1,3,7,9];
…		…
1224	};	1305	};
1225		1306
1226	$grp	1307	$grp
1227	}	1308	}
1228		1309
		1310	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1311
		1312	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1313
		1314	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1315	they execute asynchronously and pass the return value to the callback.
		1316
		1317	Both calls can be used for a lot of things, some of which make more sense
		1318	to run asynchronously in their own thread, while some others make less
		1319	sense. For example, calls that block waiting for external events, such
		1320	as locking, will also lock down an I/O thread while it is waiting, which
		1321	can deadlock the whole I/O system. At the same time, there might be no
		1322	alternative to using a thread to wait.
		1323
		1324	So in general, you should only use these calls for things that do
		1325	(filesystem) I/O, not for things that wait for other events (network,
		1326	other processes), although if you are careful and know what you are doing,
		1327	you still can.
		1328
		1329	The following constants are available and can be used for normal C<ioctl>
		1330	and C<fcntl> as well (missing ones are, as usual C<0>):
		1331
		1332	C<F_DUPFD_CLOEXEC>,
		1333
		1334	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1335
		1336	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1337
		1338	C<F_ADD_SEALS>, C<F_GET_SEALS>, C<F_SEAL_SEAL>, C<F_SEAL_SHRINK>, C<F_SEAL_GROW> and
		1339	C<F_SEAL_WRITE>.
		1340
		1341	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1342	C<FS_IOC_FIEMAP>.
		1343
		1344	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1345	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1346
		1347	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1348	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1349	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1350	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1351	C<FS_FL_USER_MODIFIABLE>.
		1352
		1353	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1354	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1355	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1356	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
		1357
		1358	C<BLKROSET>, C<BLKROGET>, C<BLKRRPART>, C<BLKGETSIZE>, C<BLKFLSBUF>, C<BLKRASET>,
		1359	C<BLKRAGET>, C<BLKFRASET>, C<BLKFRAGET>, C<BLKSECTSET>, C<BLKSECTGET>, C<BLKSSZGET>,
		1360	C<BLKBSZGET>, C<BLKBSZSET>, C<BLKGETSIZE64>,
		1361
		1362
1229	=item aio_sync $callback->($status)	1363	=item aio_sync $callback->($status)
1230		1364
1231	Asynchronously call sync and call the callback when finished.	1365	Asynchronously call sync and call the callback when finished.
1232		1366
1233	=item aio_fsync $fh, $callback->($status)	1367	=item aio_fsync $fh, $callback->($status)
…		…
1301	};	1435	};
1302		1436
1303	$grp	1437	$grp
1304	}	1438	}
1305		1439
1306	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1440	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1307		1441
1308	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1442	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1309	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1443	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1310	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1444	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1311	scalar must only be modified in-place while an aio operation is pending on	1445	scalar must only be modified in-place while an aio operation is pending on
…		…
1313		1447
1314	It calls the C<msync> function of your OS, if available, with the memory	1448	It calls the C<msync> function of your OS, if available, with the memory
1315	area starting at C<$offset> in the string and ending C<$length> bytes	1449	area starting at C<$offset> in the string and ending C<$length> bytes
1316	later. If C<$length> is negative, counts from the end, and if C<$length>	1450	later. If C<$length> is negative, counts from the end, and if C<$length>
1317	is C<undef>, then it goes till the end of the string. The flags can be	1451	is C<undef>, then it goes till the end of the string. The flags can be
1318	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1452	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1319	C<IO::AIO::MS_SYNC>.	1453	C<IO::AIO::MS_INVALIDATE>.
1320		1454
1321	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1455	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1322		1456
1323	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1457	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1324	scalars.	1458	scalars.
…		…
1354	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;	1488	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1355	aio_mlock $data; # mlock in background	1489	aio_mlock $data; # mlock in background
1356		1490
1357	=item aio_mlockall $flags, $callback->($status)	1491	=item aio_mlockall $flags, $callback->($status)
1358		1492
1359	Calls the C<mlockall> function with the given C<$flags> (a combination of	1493	Calls the C<mlockall> function with the given C<$flags> (a
1360	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).	1494	combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
		1495	C<IO::AIO::MCL_ONFAULT>).
1361		1496
1362	On systems that do not implement C<mlockall>, this function returns C<-1>	1497	On systems that do not implement C<mlockall>, this function returns C<-1>
1363	and sets errno to C<ENOSYS>.	1498	and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
		1499	by the system result in a return value of C<-1> with errno being set to
		1500	C<EINVAL>.
1364		1501
1365	Note that the corresponding C<munlockall> is synchronous and is	1502	Note that the corresponding C<munlockall> is synchronous and is
1366	documented under L<MISCELLANEOUS FUNCTIONS>.	1503	documented under L<MISCELLANEOUS FUNCTIONS>.
1367		1504
1368	Example: asynchronously lock all current and future pages into memory.	1505	Example: asynchronously lock all current and future pages into memory.
…		…
1407	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,	1544	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1408	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,	1545	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1409	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or	1546	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1410	C<IO::AIO::FIEMAP_EXTENT_SHARED>.	1547	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1411		1548
1412	At the time of this writing (Linux 3.2), this requets is unreliable unless	1549	At the time of this writing (Linux 3.2), this request is unreliable unless
1413	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing	1550	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1414	it to return all extents of a range for files with large number of	1551	it to return all extents of a range for files with a large number of
1415	extents. The code works around all these issues if C<$count> is undef.	1552	extents. The code (only) works around all these issues if C<$count> is
		1553	C<undef>.
1416		1554
1417	=item aio_group $callback->(...)	1555	=item aio_group $callback->(...)
1418		1556
1419	This is a very special aio request: Instead of doing something, it is a	1557	This is a very special aio request: Instead of doing something, it is a
1420	container for other aio requests, which is useful if you want to bundle	1558	container for other aio requests, which is useful if you want to bundle
…		…
1533	There are some caveats: when directories get renamed (or deleted), the	1671	There are some caveats: when directories get renamed (or deleted), the
1534	pathname string doesn't change, so will point to the new directory (or	1672	pathname string doesn't change, so will point to the new directory (or
1535	nowhere at all), while the directory fd, if available on the system,	1673	nowhere at all), while the directory fd, if available on the system,
1536	will still point to the original directory. Most functions accepting a	1674	will still point to the original directory. Most functions accepting a
1537	pathname will use the directory fd on newer systems, and the string on	1675	pathname will use the directory fd on newer systems, and the string on
1538	older systems. Some functions (such as realpath) will always rely on the	1676	older systems. Some functions (such as C<aio_realpath>) will always rely on
1539	string form of the pathname.	1677	the string form of the pathname.
1540		1678
1541	So this functionality is mainly useful to get some protection against	1679	So this functionality is mainly useful to get some protection against
1542	C<chdir>, to easily get an absolute path out of a relative path for future	1680	C<chdir>, to easily get an absolute path out of a relative path for future
1543	reference, and to speed up doing many operations in the same directory	1681	reference, and to speed up doing many operations in the same directory
1544	(e.g. when stat'ing all files in a directory).	1682	(e.g. when stat'ing all files in a directory).
…		…
1561	C<aio_wd> callback, as future requests using the value will fail in the	1699	C<aio_wd> callback, as future requests using the value will fail in the
1562	expected way.	1700	expected way.
1563		1701
1564	=item IO::AIO::CWD	1702	=item IO::AIO::CWD
1565		1703
1566	This is a compiletime constant (object) that represents the process	1704	This is a compile time constant (object) that represents the process
1567	current working directory.	1705	current working directory.
1568		1706
1569	Specifying this object as working directory object for a pathname is as if	1707	Specifying this object as working directory object for a pathname is as if
1570	the pathname would be specified directly, without a directory object. For	1708	the pathname would be specified directly, without a directory object. For
1571	example, these calls are functionally identical:	1709	example, these calls are functionally identical:
…		…
1752	The default value for the limit is C<0>, but note that setting a feeder	1890	The default value for the limit is C<0>, but note that setting a feeder
1753	automatically bumps it up to C<2>.	1891	automatically bumps it up to C<2>.
1754		1892
1755	=back	1893	=back
1756		1894
		1895
1757	=head2 SUPPORT FUNCTIONS	1896	=head2 SUPPORT FUNCTIONS
1758		1897
1759	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1898	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1760		1899
1761	=over 4	1900	=over 4
…		…
1826	Strictly equivalent to:	1965	Strictly equivalent to:
1827		1966
1828	IO::AIO::poll_wait, IO::AIO::poll_cb	1967	IO::AIO::poll_wait, IO::AIO::poll_cb
1829	while IO::AIO::nreqs;	1968	while IO::AIO::nreqs;
1830		1969
		1970	This function can be useful at program aborts, to make sure outstanding
		1971	I/O has been done (C<IO::AIO> uses an C<END> block which already calls
		1972	this function on normal exits), or when you are merely using C<IO::AIO>
		1973	for its more advanced functions, rather than for async I/O, e.g.:
		1974
		1975	my ($dirs, $nondirs);
		1976	IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
		1977	IO::AIO::flush;
		1978	# $dirs, $nondirs are now set
		1979
1831	=item IO::AIO::max_poll_reqs $nreqs	1980	=item IO::AIO::max_poll_reqs $nreqs
1832		1981
1833	=item IO::AIO::max_poll_time $seconds	1982	=item IO::AIO::max_poll_time $seconds
1834		1983
1835	These set the maximum number of requests (default C<0>, meaning infinity)	1984	These set the maximum number of requests (default C<0>, meaning infinity)
…		…
1861	poll => 'r', nice => 1,	2010	poll => 'r', nice => 1,
1862	cb => &IO::AIO::poll_cb);	2011	cb => &IO::AIO::poll_cb);
1863		2012
1864	=back	2013	=back
1865		2014
		2015
1866	=head3 CONTROLLING THE NUMBER OF THREADS	2016	=head3 CONTROLLING THE NUMBER OF THREADS
1867		2017
1868	=over	2018	=over
1869		2019
1870	=item IO::AIO::min_parallel $nthreads	2020	=item IO::AIO::min_parallel $nthreads
…		…
1931	longer exceeded.	2081	longer exceeded.
1932		2082
1933	In other words, this setting does not enforce a queue limit, but can be	2083	In other words, this setting does not enforce a queue limit, but can be
1934	used to make poll functions block if the limit is exceeded.	2084	used to make poll functions block if the limit is exceeded.
1935		2085
1936	This is a very bad function to use in interactive programs because it	2086	This is a bad function to use in interactive programs because it blocks,
1937	blocks, and a bad way to reduce concurrency because it is inexact: Better	2087	and a bad way to reduce concurrency because it is inexact. If you need to
		2088	issue many requests without being able to call a poll function on demand,
1938	use an C<aio_group> together with a feed callback.	2089	it is better to use an C<aio_group> together with a feed callback.
1939		2090
1940	Its main use is in scripts without an event loop - when you want to stat	2091	Its main use is in scripts without an event loop - when you want to stat a
1941	a lot of files, you can write somehting like this:	2092	lot of files, you can write something like this:
1942		2093
1943	IO::AIO::max_outstanding 32;	2094	IO::AIO::max_outstanding 32;
1944		2095
1945	for my $path (...) {	2096	for my $path (...) {
1946	aio_stat $path , ...;	2097	aio_stat $path , ...;
1947	IO::AIO::poll_cb;	2098	IO::AIO::poll_cb;
1948	}	2099	}
1949		2100
1950	IO::AIO::flush;	2101	IO::AIO::flush;
1951		2102
1952	The call to C<poll_cb> inside the loop will normally return instantly, but	2103	The call to C<poll_cb> inside the loop will normally return instantly,
1953	as soon as more thna C<32> reqeusts are in-flight, it will block until	2104	allowing the loop to progress, but as soon as more than C<32> requests
1954	some requests have been handled. This keeps the loop from pushing a large	2105	are in-flight, it will block until some requests have been handled. This
1955	number of C<aio_stat> requests onto the queue.	2106	keeps the loop from pushing a large number of C<aio_stat> requests onto
		2107	the queue (which, with many paths to stat, can use up a lot of memory).
1956		2108
1957	The default value for C<max_outstanding> is very large, so there is no	2109	The default value for C<max_outstanding> is very large, so there is no
1958	practical limit on the number of outstanding requests.	2110	practical limit on the number of outstanding requests.
1959		2111
1960	=back	2112	=back
1961		2113
		2114
1962	=head3 STATISTICAL INFORMATION	2115	=head3 STATISTICAL INFORMATION
1963		2116
1964	=over	2117	=over
1965		2118
1966	=item IO::AIO::nreqs	2119	=item IO::AIO::nreqs
…		…
1982		2135
1983	Returns the number of requests currently in the pending state (executed,	2136	Returns the number of requests currently in the pending state (executed,
1984	but not yet processed by poll_cb).	2137	but not yet processed by poll_cb).
1985		2138
1986	=back	2139	=back
		2140
		2141
		2142	=head3 SUBSECOND STAT TIME ACCESS
		2143
		2144	Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
		2145	generally find access/modification and change times with subsecond time
		2146	accuracy of the system supports it, but perl's built-in functions only
		2147	return the integer part.
		2148
		2149	The following functions return the timestamps of the most recent
		2150	stat with subsecond precision on most systems and work both after
		2151	C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
		2152	value is only meaningful after a successful C<stat>/C<lstat> call, or
		2153	during/after a successful C<aio_stat>/C<aio_lstat> callback.
		2154
		2155	This is similar to the L<Time::HiRes> C<stat> functions, but can return
		2156	full resolution without rounding and work with standard perl C<stat>,
		2157	alleviating the need to call the special C<Time::HiRes> functions, which
		2158	do not act like their perl counterparts.
		2159
		2160	On operating systems or file systems where subsecond time resolution is
		2161	not supported or could not be detected, a fractional part of C<0> is
		2162	returned, so it is always safe to call these functions.
		2163
		2164	=over 4
		2165
		2166	=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		2167
		2168	Return the access, modication, change or birth time, respectively,
		2169	including fractional part. Due to the limited precision of floating point,
		2170	the accuracy on most platforms is only a bit better than milliseconds
		2171	for times around now - see the I<nsec> function family, below, for full
		2172	accuracy.
		2173
		2174	File birth time is only available when the OS and perl support it (on
		2175	FreeBSD and NetBSD at the time of this writing, although support is
		2176	adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
		2177	it). On systems where it isn't available, C<0> is currently returned, but
		2178	this might change to C<undef> in a future version.
		2179
		2180	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		2181
		2182	Returns access, modification, change and birth time all in one go, and
		2183	maybe more times in the future version.
		2184
		2185	=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		2186
		2187	Return the fractional access, modifcation, change or birth time, in nanoseconds,
		2188	as an integer in the range C<0> to C<999999999>.
		2189
		2190	Note that no accessors are provided for access, modification and
		2191	change times - you need to get those from C<stat _> if required (C<int
		2192	IO::AIO::st_atime> and so on will I<not> generally give you the correct
		2193	value).
		2194
		2195	=item $seconds = IO::AIO::st_btimesec
		2196
		2197	The (integral) seconds part of the file birth time, if available.
		2198
		2199	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		2200
		2201	Like the functions above, but returns all four times in one go (and maybe
		2202	more in future versions).
		2203
		2204	=item $counter = IO::AIO::st_gen
		2205
		2206	Returns the generation counter (in practice this is just a random number)
		2207	of the file. This is only available on platforms which have this member in
		2208	their C<struct stat> (most BSDs at the time of this writing) and generally
		2209	only to the root usert. If unsupported, C<0> is returned, but this might
		2210	change to C<undef> in a future version.
		2211
		2212	=back
		2213
		2214	Example: print the high resolution modification time of F</etc>, using
		2215	C<stat>, and C<IO::AIO::aio_stat>.
		2216
		2217	if (stat "/etc") {
		2218	printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
		2219	}
		2220
		2221	IO::AIO::aio_stat "/etc", sub {
		2222	$_[0]
		2223	and return;
		2224
		2225	printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
		2226	};
		2227
		2228	IO::AIO::flush;
		2229
		2230	Output of the awbove on my system, showing reduced and full accuracy:
		2231
		2232	stat(/etc) mtime: 1534043702.020808
		2233	aio_stat(/etc) mtime: 1534043702.020807792
		2234
1987		2235
1988	=head3 MISCELLANEOUS FUNCTIONS	2236	=head3 MISCELLANEOUS FUNCTIONS
1989		2237
1990	IO::AIO implements some functions that are useful when you want to use	2238	IO::AIO implements some functions that are useful when you want to use
1991	some "Advanced I/O" function not available to in Perl, without going the	2239	some "Advanced I/O" function not available to in Perl, without going the
1992	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>	2240	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
1993	counterpart.	2241	counterpart.
1994		2242
1995	=over 4	2243	=over 4
		2244
		2245	=item $retval = IO::AIO::fexecve $fh, $argv, $envp
		2246
		2247	A more-or-less direct equivalent to the POSIX C<fexecve> functions, which
		2248	allows you to specify the program to be executed via a file descriptor (or
		2249	handle). Returns C<-1> and sets errno to C<ENOSYS> if not available.
		2250
		2251	=item $retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data = undef
		2252
		2253	Calls the GNU/Linux mount syscall with the given arguments. All except
		2254	C<$flags> are strings, and if C<$data> is C<undef>, a C<NULL> will be
		2255	passed.
		2256
		2257	The following values for C<$flags> are available:
		2258
		2259	C<IO::AIO::MS_RDONLY>, C<IO::AIO::MS_NOSUID>, C<IO::AIO::MS_NODEV>, C<IO::AIO::MS_NOEXEC>, C<IO::AIO::MS_SYNCHRONOUS>,
		2260	C<IO::AIO::MS_REMOUNT>, C<IO::AIO::MS_MANDLOCK>, C<IO::AIO::MS_DIRSYNC>, C<IO::AIO::MS_NOATIME>,
		2261	C<IO::AIO::MS_NODIRATIME>, C<IO::AIO::MS_BIND>, C<IO::AIO::MS_MOVE>, C<IO::AIO::MS_REC>, C<IO::AIO::MS_SILENT>,
		2262	C<IO::AIO::MS_POSIXACL>, C<IO::AIO::MS_UNBINDABLE>, C<IO::AIO::MS_PRIVATE>, C<IO::AIO::MS_SLAVE>, C<IO::AIO::MS_SHARED>,
		2263	C<IO::AIO::MS_RELATIME>, C<IO::AIO::MS_KERNMOUNT>, C<IO::AIO::MS_I_VERSION>, C<IO::AIO::MS_STRICTATIME>,
		2264	C<IO::AIO::MS_LAZYTIME>, C<IO::AIO::MS_ACTIVE>, C<IO::AIO::MS_NOUSER>, C<IO::AIO::MS_RMT_MASK>, C<IO::AIO::MS_MGC_VAL> and
		2265	C<IO::AIO::MS_MGC_MSK>.
		2266
		2267	=item $retval = IO::AIO::umount $path, $flags = 0
		2268
		2269	Invokes the GNU/Linux C<umount> or C<umount2> syscalls. Always calls
		2270	C<umount> if C<$flags> is C<0>, otherwqise always tries to call
		2271	C<umount2>.
		2272
		2273	The following C<$flags> are available:
		2274
		2275	C<IO::AIO::MNT_FORCE>, C<IO::AIO::MNT_DETACH>, C<IO::AIO::MNT_EXPIRE> and C<IO::AIO::UMOUNT_NOFOLLOW>.
		2276
		2277	=item $numfd = IO::AIO::get_fdlimit
		2278
		2279	Tries to find the current file descriptor limit and returns it, or
		2280	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2281	the highest valid file descriptor number.
		2282
		2283	=item IO::AIO::min_fdlimit [$numfd]
		2284
		2285	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2286	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2287	is missing, it will try to set a very high limit, although this is not
		2288	recommended when you know the actual minimum that you require.
		2289
		2290	If the limit cannot be raised enough, the function makes a best-effort
		2291	attempt to increase the limit as much as possible, using various
		2292	tricks, while still failing. You can query the resulting limit using
		2293	C<IO::AIO::get_fdlimit>.
		2294
		2295	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2296	true.
1996		2297
1997	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2298	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1998		2299
1999	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2300	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
2000	but is blocking (this makes most sense if you know the input data is	2301	but is blocking (this makes most sense if you know the input data is
…		…
2017	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2318	=item IO::AIO::madvise $scalar, $offset, $len, $advice
2018		2319
2019	Simply calls the C<posix_madvise> function (see its	2320	Simply calls the C<posix_madvise> function (see its
2020	manpage for details). The following advice constants are	2321	manpage for details). The following advice constants are
2021	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2322	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2022	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2323	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2324	C<IO::AIO::MADV_DONTNEED>.
		2325
		2326	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2327	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2328	will be reduced to fit into the C<$scalar>.
2023		2329
2024	On systems that do not implement C<posix_madvise>, this function returns	2330	On systems that do not implement C<posix_madvise>, this function returns
2025	ENOSYS, otherwise the return value of C<posix_madvise>.	2331	ENOSYS, otherwise the return value of C<posix_madvise>.
2026		2332
2027	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2333	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
2029	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2335	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2030	$scalar (see its manpage for details). The following protect	2336	$scalar (see its manpage for details). The following protect
2031	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2337	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2032	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2338	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2033		2339
		2340	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2341	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2342	will be reduced to fit into the C<$scalar>.
		2343
2034	On systems that do not implement C<mprotect>, this function returns	2344	On systems that do not implement C<mprotect>, this function returns
2035	ENOSYS, otherwise the return value of C<mprotect>.	2345	ENOSYS, otherwise the return value of C<mprotect>.
2036		2346
2037	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2347	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2038		2348
2039	Memory-maps a file (or anonymous memory range) and attaches it to the	2349	Memory-maps a file (or anonymous memory range) and attaches it to the
2040	given C<$scalar>, which will act like a string scalar. Returns true on	2350	given C<$scalar>, which will act like a string scalar. Returns true on
2041	success, and false otherwise.	2351	success, and false otherwise.
2042		2352
		2353	The scalar must exist, but its contents do not matter - this means you
		2354	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2355	the scalar first.
		2356
2043	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2357	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2044	change the string length, and most read-only operations such as copying it	2358	which don't change the string length, and most read-only operations such
2045	or searching it with regexes and so on.	2359	as copying it or searching it with regexes and so on.
2046		2360
2047	Anything else is unsafe and will, at best, result in memory leaks.	2361	Anything else is unsafe and will, at best, result in memory leaks.
2048		2362
2049	The memory map associated with the C<$scalar> is automatically removed	2363	The memory map associated with the C<$scalar> is automatically removed
2050	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2364	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2051	C<IO::AIO::munmap> functions are called.	2365	or C<IO::AIO::munmap> functions are called on it.
2052		2366
2053	This calls the C<mmap>(2) function internally. See your system's manual	2367	This calls the C<mmap>(2) function internally. See your system's manual
2054	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2368	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2055		2369
2056	The C<$length> must be larger than zero and smaller than the actual	2370	The C<$length> must be larger than zero and smaller than the actual
2057	filesize.	2371	filesize.
2058		2372
2059	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2373	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2060	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2374	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2061		2375
2062	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2376	C<$flags> can be a combination of
2063	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2377	C<IO::AIO::MAP_SHARED> or
2064	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2378	C<IO::AIO::MAP_PRIVATE>,
		2379	or a number of system-specific flags (when not available, the are C<0>):
2065	(which is set to C<MAP_ANON> if your system only provides this	2380	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2066	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2381	C<IO::AIO::MAP_LOCKED>,
2067	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2382	C<IO::AIO::MAP_NORESERVE>,
		2383	C<IO::AIO::MAP_POPULATE>,
2068	C<IO::AIO::MAP_NONBLOCK>	2384	C<IO::AIO::MAP_NONBLOCK>,
		2385	C<IO::AIO::MAP_FIXED>,
		2386	C<IO::AIO::MAP_GROWSDOWN>,
		2387	C<IO::AIO::MAP_32BIT>,
		2388	C<IO::AIO::MAP_HUGETLB>,
		2389	C<IO::AIO::MAP_STACK>,
		2390	C<IO::AIO::MAP_FIXED_NOREPLACE>,
		2391	C<IO::AIO::MAP_SHARED_VALIDATE>,
		2392	C<IO::AIO::MAP_SYNC> or
		2393	C<IO::AIO::MAP_UNINITIALIZED>.
2069		2394
2070	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2395	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2071		2396
2072	C<$offset> is the offset from the start of the file - it generally must be	2397	C<$offset> is the offset from the start of the file - it generally must be
2073	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2398	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
2087		2412
2088	=item IO::AIO::munmap $scalar	2413	=item IO::AIO::munmap $scalar
2089		2414
2090	Removes a previous mmap and undefines the C<$scalar>.	2415	Removes a previous mmap and undefines the C<$scalar>.
2091		2416
		2417	=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
		2418
		2419	Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
		2420	been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
		2421	C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
		2422
		2423	Returns true if successful, and false otherwise. If the underlying mmapped
		2424	region has changed address, then the true value has the numerical value
		2425	C<1>, otherwise it has the numerical value C<0>:
		2426
		2427	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		2428	or die "mremap: $!";
		2429
		2430	if ($success*1) {
		2431	warn "scalar has chanegd address in memory\n";
		2432	}
		2433
		2434	C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
		2435	implemented, but not supported and might go away in a future version.
		2436
		2437	On systems where this call is not supported or is not emulated, this call
		2438	returns falls and sets C<$!> to C<ENOSYS>.
		2439
		2440	=item IO::AIO::mlockall $flags
		2441
		2442	Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
		2443	but is blocking.
		2444
2092	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef	2445	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2093		2446
2094	Calls the C<munlock> function, undoing the effects of a previous	2447	Calls the C<munlock> function, undoing the effects of a previous
2095	C<aio_mlock> call (see its description for details).	2448	C<aio_mlock> call (see its description for details).
2096		2449
…		…
2098		2451
2099	Calls the C<munlockall> function.	2452	Calls the C<munlockall> function.
2100		2453
2101	On systems that do not implement C<munlockall>, this function returns	2454	On systems that do not implement C<munlockall>, this function returns
2102	ENOSYS, otherwise the return value of C<munlockall>.	2455	ENOSYS, otherwise the return value of C<munlockall>.
		2456
		2457	=item $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
		2458
		2459	Uses the GNU/Linux C<accept4(2)> syscall, if available, to accept a socket
		2460	and return the new file handle on success, or sets C<$!> and returns
		2461	C<undef> on error.
		2462
		2463	The remote name of the new socket will be stored in C<$sockaddr>, which
		2464	will be extended to allow for at least C<$sockaddr_maxlen> octets. If the
		2465	socket name does not fit into C<$sockaddr_maxlen> octets, this is signaled
		2466	by returning a longer string in C<$sockaddr>, which might or might not be
		2467	truncated.
		2468
		2469	To accept name-less sockets, use C<undef> for C<$sockaddr> and C<0> for
		2470	C<$sockaddr_maxlen>.
		2471
		2472	The main reasons to use this syscall rather than portable C<accept(2)>
		2473	are that you can specify C<SOCK_NONBLOCK> and/or C<SOCK_CLOEXEC>
		2474	flags and you can accept name-less sockets by specifying C<0> for
		2475	C<$sockaddr_maxlen>, which is sadly not possible with perl's interface to
		2476	C<accept>.
2103		2477
2104	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags	2478	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2105		2479
2106	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or	2480	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2107	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they	2481	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
…		…
2145	C<$flags> is non-zero, fails with C<ENOSYS>.	2519	C<$flags> is non-zero, fails with C<ENOSYS>.
2146		2520
2147	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the	2521	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2148	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and	2522	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2149	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.	2523	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2524
		2525	Example: create a pipe race-free w.r.t. threads and fork:
		2526
		2527	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2528	or die "pipe2: $!\n";
		2529
		2530	=item $fh = IO::AIO::memfd_create $pathname[, $flags]
		2531
		2532	This is a direct interface to the Linux L<memfd_create(2)> system
		2533	call. The (unhelpful) default for C<$flags> is C<0>, but your default
		2534	should be C<IO::AIO::MFD_CLOEXEC>.
		2535
		2536	On success, the new memfd filehandle is returned, otherwise returns
		2537	C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
		2538
		2539	Please refer to L<memfd_create(2)> for more info on this call.
		2540
		2541	The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
		2542	C<IO::AIO::MFD_ALLOW_SEALING>, C<IO::AIO::MFD_HUGETLB>,
		2543	C<IO::AIO::MFD_HUGETLB_2MB> and C<IO::AIO::MFD_HUGETLB_1GB>.
		2544
		2545	Example: create a new memfd.
		2546
		2547	my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
		2548	or die "memfd_create: $!\n";
		2549
		2550	=item $fh = IO::AIO::pidfd_open $pid[, $flags]
		2551
		2552	This is an interface to the Linux L<pidfd_open(2)> system call. The
		2553	default for C<$flags> is C<0>.
		2554
		2555	On success, a new pidfd filehandle is returned (that is already set to
		2556	close-on-exec), otherwise returns C<undef>. If the syscall is missing,
		2557	fails with C<ENOSYS>.
		2558
		2559	Example: open pid 6341 as pidfd.
		2560
		2561	my $fh = IO::AIO::pidfd_open 6341
		2562	or die "pidfd_open: $!\n";
		2563
		2564	=item $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
		2565
		2566	This is an interface to the Linux L<pidfd_send_signal> system call. The
		2567	default for C<$siginfo> is C<undef> and the default for C<$flags> is C<0>.
		2568
		2569	Returns the system call status. If the syscall is missing, fails with
		2570	C<ENOSYS>.
		2571
		2572	When specified, C<$siginfo> must be a reference to a hash with one or more
		2573	of the following members:
		2574
		2575	=over
		2576
		2577	=item code - the C<si_code> member
		2578
		2579	=item pid - the C<si_pid> member
		2580
		2581	=item uid - the C<si_uid> member
		2582
		2583	=item value_int - the C<si_value.sival_int> member
		2584
		2585	=item value_ptr - the C<si_value.sival_ptr> member, specified as an integer
		2586
		2587	=back
		2588
		2589	Example: send a SIGKILL to the specified process.
		2590
		2591	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
		2592	and die "pidfd_send_signal: $!\n";
		2593
		2594	Example: send a SIGKILL to the specified process with extra data.
		2595
		2596	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
		2597	and die "pidfd_send_signal: $!\n";
		2598
		2599	=item $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
		2600
		2601	This is an interface to the Linux L<pidfd_getfd> system call. The default
		2602	for C<$flags> is C<0>.
		2603
		2604	On success, returns a dup'ed copy of the target file descriptor (specified
		2605	as an integer) returned (that is already set to close-on-exec), otherwise
		2606	returns C<undef>. If the syscall is missing, fails with C<ENOSYS>.
		2607
		2608	Example: get a copy of standard error of another process and print soemthing to it.
		2609
		2610	my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
		2611	or die "pidfd_getfd: $!\n";
		2612	print $errfh "stderr\n";
		2613
		2614	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2615
		2616	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2617	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2618
		2619	On success, the new eventfd filehandle is returned, otherwise returns
		2620	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2621
		2622	Please refer to L<eventfd(2)> for more info on this call.
		2623
		2624	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2625	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2626
		2627	Example: create a new eventfd filehandle:
		2628
		2629	$fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
		2630	or die "eventfd: $!\n";
		2631
		2632	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2633
		2634	This is a direct interface to the Linux L<timerfd_create(2)> system
		2635	call. The (unhelpful) default for C<$flags> is C<0>, but your default
		2636	should be C<IO::AIO::TFD_CLOEXEC>.
		2637
		2638	On success, the new timerfd filehandle is returned, otherwise returns
		2639	C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
		2640
		2641	Please refer to L<timerfd_create(2)> for more info on this call.
		2642
		2643	The following C<$clockid> values are
		2644	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2645	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2646	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2647	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2648
		2649	The following C<$flags> values are available (Linux
		2650	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2651
		2652	Example: create a new timerfd and set it to one-second repeated alarms,
		2653	then wait for two alarms:
		2654
		2655	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2656	or die "timerfd_create: $!\n";
		2657
		2658	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2659	or die "timerfd_settime: $!\n";
		2660
		2661	for (1..2) {
		2662	8 == sysread $fh, my $buf, 8
		2663	or die "timerfd read failure\n";
		2664
		2665	printf "number of expirations (likely 1): %d\n",
		2666	unpack "Q", $buf;
		2667	}
		2668
		2669	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2670
		2671	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2672	call. Please refer to its manpage for more info on this call.
		2673
		2674	The new itimerspec is specified using two (possibly fractional) second
		2675	values, C<$new_interval> and C<$new_value>).
		2676
		2677	On success, the current interval and value are returned (as per
		2678	C<timerfd_gettime>). On failure, the empty list is returned.
		2679
		2680	The following C<$flags> values are
		2681	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2682	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2683
		2684	See C<IO::AIO::timerfd_create> for a full example.
		2685
		2686	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2687
		2688	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2689	call. Please refer to its manpage for more info on this call.
		2690
		2691	On success, returns the current values of interval and value for the given
		2692	timerfd (as potentially fractional second values). On failure, the empty
		2693	list is returned.
2150		2694
2151	=back	2695	=back
2152		2696
2153	=cut	2697	=cut
2154		2698
…		…
2220	the process will result in undefined behaviour. Calling it at any time	2764	the process will result in undefined behaviour. Calling it at any time
2221	will also result in any undefined (by POSIX) behaviour.	2765	will also result in any undefined (by POSIX) behaviour.
2222		2766
2223	=back	2767	=back
2224		2768
		2769	=head2 LINUX-SPECIFIC CALLS
		2770
		2771	When a call is documented as "linux-specific" then this means it
		2772	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2773	availability and compatibility of such calls regardless of the platform
		2774	it is compiled on, so platforms such as FreeBSD which often implement
		2775	these calls will work. When in doubt, call them and see if they fail wth
		2776	C<ENOSYS>.
		2777
2225	=head2 MEMORY USAGE	2778	=head2 MEMORY USAGE
2226		2779
2227	Per-request usage:	2780	Per-request usage:
2228		2781
2229	Each aio request uses - depending on your architecture - around 100-200	2782	Each aio request uses - depending on your architecture - around 100-200
…		…
2241	temporary buffers, and each thread requires a stack and other data	2794	temporary buffers, and each thread requires a stack and other data
2242	structures (usually around 16k-128k, depending on the OS).	2795	structures (usually around 16k-128k, depending on the OS).
2243		2796
2244	=head1 KNOWN BUGS	2797	=head1 KNOWN BUGS
2245		2798
2246	Known bugs will be fixed in the next release.	2799	Known bugs will be fixed in the next release :)
		2800
		2801	=head1 KNOWN ISSUES
		2802
		2803	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2804	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2805	non-created hash slots or other scalars I didn't think of. It's best to
		2806	avoid such and either use scalar variables or making sure that the scalar
		2807	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2808
		2809	I am not sure anything can be done about this, so this is considered a
		2810	known issue, rather than a bug.
2247		2811
2248	=head1 SEE ALSO	2812	=head1 SEE ALSO
2249		2813
2250	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2814	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2251	more natural syntax.	2815	more natural syntax and L<IO::FDPass> for file descriptor passing.
2252		2816
2253	=head1 AUTHOR	2817	=head1 AUTHOR
2254		2818
2255	Marc Lehmann <schmorp@schmorp.de>	2819	Marc Lehmann <schmorp@schmorp.de>
2256	http://home.schmorp.de/	2820	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.254 by root, Thu Jun 25 13:42:18 2015 UTC vs. Revision 1.319 by root, Wed Sep 27 03:09:57 2023 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.254 by root, Thu Jun 25 13:42:18 2015 UTC vs.
Revision 1.319 by root, Wed Sep 27 03:09:57 2023 UTC