[ViewVC] Diff of: cvs/IO-AIO/README

Comparing IO-AIO/README (file contents):
Revision 1.53 by root, Thu Oct 11 03:20:52 2012 UTC vs.
Revision 1.69 by root, Tue Sep 6 10:56:12 2022 UTC

…		…
1	NAME	1	NAME
2	IO::AIO - Asynchronous Input/Output	2	IO::AIO - Asynchronous/Advanced Input/Output
3		3
4	SYNOPSIS	4	SYNOPSIS
5	use IO::AIO;	5	use IO::AIO;
6		6
7	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {	7	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
55	not well-supported or restricted (GNU/Linux doesn't allow them on normal	55	not well-supported or restricted (GNU/Linux doesn't allow them on normal
56	files currently, for example), and they would only support aio_read and	56	files currently, for example), and they would only support aio_read and
57	aio_write, so the remaining functionality would have to be implemented	57	aio_write, so the remaining functionality would have to be implemented
58	using threads anyway.	58	using threads anyway.
59		59
		60	In addition to asynchronous I/O, this module also exports some rather
		61	arcane interfaces, such as "madvise" or linux's "splice" system call,
		62	which is why the "A" in "AIO" can also mean advanced.
		63
60	Although the module will work in the presence of other (Perl-) threads,	64	Although the module will work in the presence of other (Perl-) threads,
61	it is currently not reentrant in any way, so use appropriate locking	65	it is currently not reentrant in any way, so use appropriate locking
62	yourself, always call "poll_cb" from within the same thread, or never	66	yourself, always call "poll_cb" from within the same thread, or never
63	call "poll_cb" (or other "aio_" functions) recursively.	67	call "poll_cb" (or other "aio_" functions) recursively.
64		68
65	EXAMPLE	69	EXAMPLE
66	This is a simple example that uses the EV module and loads /etc/passwd	70	This is a simple example that uses the EV module and loads /etc/passwd
67	asynchronously:	71	asynchronously:
68		72
69	use Fcntl;
70	use EV;	73	use EV;
71	use IO::AIO;	74	use IO::AIO;
72		75
73	# register the IO::AIO callback with EV	76	# register the IO::AIO callback with EV
74	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	77	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
91		94
92	# file contents now in $contents	95	# file contents now in $contents
93	print $contents;	96	print $contents;
94		97
95	# exit event loop and program	98	# exit event loop and program
96	EV::unloop;	99	EV::break;
97	};	100	};
98	};	101	};
99		102
100	# possibly queue up other requests, or open GUI windows,	103	# possibly queue up other requests, or open GUI windows,
101	# check for sockets etc. etc.	104	# check for sockets etc. etc.
102		105
103	# process events as long as there are some:	106	# process events as long as there are some:
104	EV::loop;	107	EV::run;
105		108
106	REQUEST ANATOMY AND LIFETIME	109	REQUEST ANATOMY AND LIFETIME
107	Every "aio_*" function creates a request. which is a C data structure	110	Every "aio_*" function creates a request. which is a C data structure
108	not directly visible to Perl.	111	not directly visible to Perl.
109		112
…		…
172	aio_unlink $pathname, $callback->($status)	175	aio_unlink $pathname, $callback->($status)
173	aio_mknod $pathname, $mode, $dev, $callback->($status)	176	aio_mknod $pathname, $mode, $dev, $callback->($status)
174	aio_link $srcpath, $dstpath, $callback->($status)	177	aio_link $srcpath, $dstpath, $callback->($status)
175	aio_symlink $srcpath, $dstpath, $callback->($status)	178	aio_symlink $srcpath, $dstpath, $callback->($status)
176	aio_readlink $pathname, $callback->($link)	179	aio_readlink $pathname, $callback->($link)
177	aio_realpath $pathname, $callback->($link)	180	aio_realpath $pathname, $callback->($path)
178	aio_rename $srcpath, $dstpath, $callback->($status)	181	aio_rename $srcpath, $dstpath, $callback->($status)
		182	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
179	aio_mkdir $pathname, $mode, $callback->($status)	183	aio_mkdir $pathname, $mode, $callback->($status)
180	aio_rmdir $pathname, $callback->($status)	184	aio_rmdir $pathname, $callback->($status)
181	aio_readdir $pathname, $callback->($entries)	185	aio_readdir $pathname, $callback->($entries)
182	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	186	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
183	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	187	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
…		…
185	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	189	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
186	aio_load $pathname, $data, $callback->($status)	190	aio_load $pathname, $data, $callback->($status)
187	aio_copy $srcpath, $dstpath, $callback->($status)	191	aio_copy $srcpath, $dstpath, $callback->($status)
188	aio_move $srcpath, $dstpath, $callback->($status)	192	aio_move $srcpath, $dstpath, $callback->($status)
189	aio_rmtree $pathname, $callback->($status)	193	aio_rmtree $pathname, $callback->($status)
		194	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		195	aio_ioctl $fh, $request, $buf, $callback->($status)
190	aio_sync $callback->($status)	196	aio_sync $callback->($status)
191	aio_syncfs $fh, $callback->($status)	197	aio_syncfs $fh, $callback->($status)
192	aio_fsync $fh, $callback->($status)	198	aio_fsync $fh, $callback->($status)
193	aio_fdatasync $fh, $callback->($status)	199	aio_fdatasync $fh, $callback->($status)
194	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	200	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
195	aio_pathsync $pathname, $callback->($status)	201	aio_pathsync $pathname, $callback->($status)
196	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	202	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
197	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	203	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
198	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	204	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
199	aio_mlockall $flags, $callback->($status)	205	aio_mlockall $flags, $callback->($status)
200	aio_group $callback->(...)	206	aio_group $callback->(...)
201	aio_nop $callback->()	207	aio_nop $callback->()
…		…
215	IO::AIO::idle_timeout $seconds	221	IO::AIO::idle_timeout $seconds
216	IO::AIO::max_outstanding $maxreqs	222	IO::AIO::max_outstanding $maxreqs
217	IO::AIO::nreqs	223	IO::AIO::nreqs
218	IO::AIO::nready	224	IO::AIO::nready
219	IO::AIO::npending	225	IO::AIO::npending
		226	IO::AIO::reinit
		227
		228	$nfd = IO::AIO::get_fdlimit
		229	IO::AIO::min_fdlimit $nfd
220		230
221	IO::AIO::sendfile $ofh, $ifh, $offset, $count	231	IO::AIO::sendfile $ofh, $ifh, $offset, $count
222	IO::AIO::fadvise $fh, $offset, $len, $advice	232	IO::AIO::fadvise $fh, $offset, $len, $advice
		233	IO::AIO::fexecve $fh, $argv, $envp
		234
223	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]	235	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
224	IO::AIO::munmap $scalar	236	IO::AIO::munmap $scalar
		237	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
225	IO::AIO::madvise $scalar, $offset, $length, $advice	238	IO::AIO::madvise $scalar, $offset, $length, $advice
226	IO::AIO::mprotect $scalar, $offset, $length, $protect	239	IO::AIO::mprotect $scalar, $offset, $length, $protect
227	IO::AIO::munlock $scalar, $offset = 0, $length = undef	240	IO::AIO::munlock $scalar, $offset = 0, $length = undef
228	IO::AIO::munlockall	241	IO::AIO::munlockall
		242
		243	# stat extensions
		244	$counter = IO::AIO::st_gen
		245	$seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		246	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		247	$nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		248	$seconds = IO::AIO::st_btimesec
		249	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		250
		251	# very much unportable syscalls
		252	IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
		253	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		254	IO::AIO::tee $r_fh, $w_fh, $length, $flags
		255
		256	$actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		257	($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		258
		259	$fh = IO::AIO::eventfd [$initval, [$flags]]
		260	$fh = IO::AIO::memfd_create $pathname[, $flags]
		261
		262	$fh = IO::AIO::timerfd_create $clockid[, $flags]
		263	($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		264	($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		265
		266	$fh = IO::AIO::pidfd_open $pid[, $flags]
		267	$status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
		268	$fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
		269
		270	$retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data = undef
		271	$retval = IO::AIO::umount $path, $flags = 0
229		272
230	API NOTES	273	API NOTES
231	All the "aio_*" calls are more or less thin wrappers around the syscall	274	All the "aio_*" calls are more or less thin wrappers around the syscall
232	with the same name (sans "aio_"). The arguments are similar or	275	with the same name (sans "aio_"). The arguments are similar or
233	identical, and they all accept an additional (and optional) $callback	276	identical, and they all accept an additional (and optional) $callback
…		…
331	"O_APPEND"), the following POSIX and non-POSIX constants are	374	"O_APPEND"), the following POSIX and non-POSIX constants are
332	available (missing ones on your system are, as usual, 0):	375	available (missing ones on your system are, as usual, 0):
333		376
334	"O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",	377	"O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
335	"O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",	378	"O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
336	"O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT".	379	"O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", "O_TTY_INIT"
		380	and "O_ACCMODE".
337		381
338	aio_close $fh, $callback->($status)	382	aio_close $fh, $callback->($status)
339	Asynchronously close a file and call the callback with the result	383	Asynchronously close a file and call the callback with the result
340	code.	384	code.
341		385
…		…
371		415
372	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	416	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
373	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	417	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
374	Reads or writes $length bytes from or to the specified $fh and	418	Reads or writes $length bytes from or to the specified $fh and
375	$offset into the scalar given by $data and offset $dataoffset and	419	$offset into the scalar given by $data and offset $dataoffset and
376	calls the callback without the actual number of bytes read (or -1 on	420	calls the callback with the actual number of bytes transferred (or
377	error, just like the syscall).	421	-1 on error, just like the syscall).
378		422
379	"aio_read" will, like "sysread", shrink or grow the $data scalar to	423	"aio_read" will, like "sysread", shrink or grow the $data scalar to
380	offset plus the actual number of bytes read.	424	offset plus the actual number of bytes read.
381		425
382	If $offset is undefined, then the current file descriptor offset	426	If $offset is undefined, then the current file descriptor offset
…		…
439	As native sendfile syscalls (as practically any non-POSIX interface	483	As native sendfile syscalls (as practically any non-POSIX interface
440	hacked together in a hurry to improve benchmark numbers) tend to be	484	hacked together in a hurry to improve benchmark numbers) tend to be
441	rather buggy on many systems, this implementation tries to work	485	rather buggy on many systems, this implementation tries to work
442	around some known bugs in Linux and FreeBSD kernels (probably	486	around some known bugs in Linux and FreeBSD kernels (probably
443	others, too), but that might fail, so you really really should check	487	others, too), but that might fail, so you really really should check
444	the return value of "aio_sendfile" - fewre bytes than expected might	488	the return value of "aio_sendfile" - fewer bytes than expected might
445	have been transferred.	489	have been transferred.
446		490
447	aio_readahead $fh,$offset,$length, $callback->($retval)	491	aio_readahead $fh,$offset,$length, $callback->($retval)
448	"aio_readahead" populates the page cache with data from a file so	492	"aio_readahead" populates the page cache with data from a file so
449	that subsequent reads from that file will not block on disk I/O. The	493	that subsequent reads from that file will not block on disk I/O. The
…		…
453	to a page boundary and bytes are read up to the next page boundary	497	to a page boundary and bytes are read up to the next page boundary
454	greater than or equal to (off-set+length). "aio_readahead" does not	498	greater than or equal to (off-set+length). "aio_readahead" does not
455	read beyond the end of the file. The current file offset of the file	499	read beyond the end of the file. The current file offset of the file
456	is left unchanged.	500	is left unchanged.
457		501
458	If that syscall doesn't exist (likely if your OS isn't Linux) it	502	If that syscall doesn't exist (likely if your kernel isn't Linux) it
459	will be emulated by simply reading the data, which would have a	503	will be emulated by simply reading the data, which would have a
460	similar effect.	504	similar effect.
461		505
462	aio_stat $fh_or_path, $callback->($status)	506	aio_stat $fh_or_path, $callback->($status)
463	aio_lstat $fh, $callback->($status)	507	aio_lstat $fh, $callback->($status)
464	Works like perl's "stat" or "lstat" in void context. The callback	508	Works almost exactly like perl's "stat" or "lstat" in void context.
465	will be called after the stat and the results will be available	509	The callback will be called after the stat and the results will be
466	using "stat _" or "-s _" etc...	510	available using "stat _" or "-s _" and other tests (with the
		511	exception of "-B" and "-T").
467		512
468	The pathname passed to "aio_stat" must be absolute. See API NOTES,	513	The pathname passed to "aio_stat" must be absolute. See API NOTES,
469	above, for an explanation.	514	above, for an explanation.
470		515
471	Currently, the stats are always 64-bit-stats, i.e. instead of	516	Currently, the stats are always 64-bit-stats, i.e. instead of
…		…
479	back on traditional behaviour).	524	back on traditional behaviour).
480		525
481	"S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",	526	"S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
482	"S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",	527	"S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
483	"IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".	528	"IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
		529
		530	To access higher resolution stat timestamps, see "SUBSECOND STAT
		531	TIME ACCESS".
484		532
485	Example: Print the length of /etc/passwd:	533	Example: Print the length of /etc/passwd:
486		534
487	aio_stat "/etc/passwd", sub {	535	aio_stat "/etc/passwd", sub {
488	$_[0] and die "stat failed: $!";	536	$_[0] and die "stat failed: $!";
…		…
530	namemax => 255,	578	namemax => 255,
531	frsize => 1024,	579	frsize => 1024,
532	fsid => 1810	580	fsid => 1810
533	}	581	}
534		582
535	Here is a (likely partial) list of fsid values used by Linux - it is
536	safe to hardcode these when the $^O is "linux":
537
538	0x0000adf5 adfs
539	0x0000adff affs
540	0x5346414f afs
541	0x09041934 anon-inode filesystem
542	0x00000187 autofs
543	0x42465331 befs
544	0x1badface bfs
545	0x42494e4d binfmt_misc
546	0x9123683e btrfs
547	0x0027e0eb cgroupfs
548	0xff534d42 cifs
549	0x73757245 coda
550	0x012ff7b7 coh
551	0x28cd3d45 cramfs
552	0x453dcd28 cramfs-wend (wrong endianness)
553	0x64626720 debugfs
554	0x00001373 devfs
555	0x00001cd1 devpts
556	0x0000f15f ecryptfs
557	0x00414a53 efs
558	0x0000137d ext
559	0x0000ef53 ext2/ext3
560	0x0000ef51 ext2
561	0x00004006 fat
562	0x65735546 fuseblk
563	0x65735543 fusectl
564	0x0bad1dea futexfs
565	0x01161970 gfs2
566	0x47504653 gpfs
567	0x00004244 hfs
568	0xf995e849 hpfs
569	0x958458f6 hugetlbfs
570	0x2bad1dea inotifyfs
571	0x00009660 isofs
572	0x000072b6 jffs2
573	0x3153464a jfs
574	0x6b414653 k-afs
575	0x0bd00bd0 lustre
576	0x0000137f minix
577	0x0000138f minix 30 char names
578	0x00002468 minix v2
579	0x00002478 minix v2 30 char names
580	0x00004d5a minix v3
581	0x19800202 mqueue
582	0x00004d44 msdos
583	0x0000564c novell
584	0x00006969 nfs
585	0x6e667364 nfsd
586	0x00003434 nilfs
587	0x5346544e ntfs
588	0x00009fa1 openprom
589	0x7461636F ocfs2
590	0x00009fa0 proc
591	0x6165676c pstorefs
592	0x0000002f qnx4
593	0x858458f6 ramfs
594	0x52654973 reiserfs
595	0x00007275 romfs
596	0x67596969 rpc_pipefs
597	0x73636673 securityfs
598	0xf97cff8c selinux
599	0x0000517b smb
600	0x534f434b sockfs
601	0x73717368 squashfs
602	0x62656572 sysfs
603	0x012ff7b6 sysv2
604	0x012ff7b5 sysv4
605	0x01021994 tmpfs
606	0x15013346 udf
607	0x00011954 ufs
608	0x54190100 ufs byteswapped
609	0x00009fa2 usbdevfs
610	0x01021997 v9fs
611	0xa501fcf5 vxfs
612	0xabba1974 xenfs
613	0x012ff7b4 xenix
614	0x58465342 xfs
615	0x012fd16d xia
616
617	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	583	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
618	Works like perl's "utime" function (including the special case of	584	Works like perl's "utime" function (including the special case of
619	$atime and $mtime being undef). Fractional times are supported if	585	$atime and $mtime being undef). Fractional times are supported if
620	the underlying syscalls support them.	586	the underlying syscalls support them.
621		587
622	When called with a pathname, uses utimes(2) if available, otherwise	588	When called with a pathname, uses utimensat(2) or utimes(2) if
623	utime(2). If called on a file descriptor, uses futimes(2) if	589	available, otherwise utime(2). If called on a file descriptor, uses
624	available, otherwise returns ENOSYS, so this is not portable.	590	futimens(2) or futimes(2) if available, otherwise returns ENOSYS, so
		591	this is not portable.
625		592
626	Examples:	593	Examples:
627		594
628	# set atime and mtime to current time (basically touch(1)):	595	# set atime and mtime to current time (basically touch(1)):
629	aio_utime "path", undef, undef;	596	aio_utime "path", undef, undef;
…		…
644		611
645	aio_truncate $fh_or_path, $offset, $callback->($status)	612	aio_truncate $fh_or_path, $offset, $callback->($status)
646	Works like truncate(2) or ftruncate(2).	613	Works like truncate(2) or ftruncate(2).
647		614
648	aio_allocate $fh, $mode, $offset, $len, $callback->($status)	615	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
649	Allocates or freed disk space according to the $mode argument. See	616	Allocates or frees disk space according to the $mode argument. See
650	the linux "fallocate" docuemntation for details.	617	the linux "fallocate" documentation for details.
651		618
652	$mode can currently be 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to	619	$mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
653	allocate space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE \|	620	space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE \|
654	IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.	621	IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
655		622
		623	IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range
		624	(without leaving a hole), "FALLOC_FL_ZERO_RANGE", to zero a range,
		625	"FALLOC_FL_INSERT_RANGE" to insert a range and
		626	"FALLOC_FL_UNSHARE_RANGE" to unshare shared blocks (see your
		627	fallocate(2) manpage).
		628
656	The file system block size used by "fallocate" is presumably the	629	The file system block size used by "fallocate" is presumably the
657	"f_bsize" returned by "statvfs".	630	"f_bsize" returned by "statvfs", but different filesystems and
		631	filetypes can dictate other limitations.
658		632
659	If "fallocate" isn't available or cannot be emulated (currently no	633	If "fallocate" isn't available or cannot be emulated (currently no
660	emulation will be attempted), passes -1 and sets $! to "ENOSYS".	634	emulation will be attempted), passes -1 and sets $! to "ENOSYS".
661		635
662	aio_chmod $fh_or_path, $mode, $callback->($status)	636	aio_chmod $fh_or_path, $mode, $callback->($status)
…		…
692	the callback. If an error occurs, nothing or undef gets passed to	666	the callback. If an error occurs, nothing or undef gets passed to
693	the callback.	667	the callback.
694		668
695	aio_realpath $pathname, $callback->($path)	669	aio_realpath $pathname, $callback->($path)
696	Asynchronously make the path absolute and resolve any symlinks in	670	Asynchronously make the path absolute and resolve any symlinks in
697	$path. The resulting path only consists of directories (Same as	671	$path. The resulting path only consists of directories (same as
698	Cwd::realpath).	672	Cwd::realpath).
699		673
700	This request can be used to get the absolute path of the current	674	This request can be used to get the absolute path of the current
701	working directory by passing it a path of . (a single dot).	675	working directory by passing it a path of . (a single dot).
702		676
703	aio_rename $srcpath, $dstpath, $callback->($status)	677	aio_rename $srcpath, $dstpath, $callback->($status)
704	Asynchronously rename the object at $srcpath to $dstpath, just as	678	Asynchronously rename the object at $srcpath to $dstpath, just as
705	rename(2) and call the callback with the result code.	679	rename(2) and call the callback with the result code.
		680
		681	On systems that support the AIO::WD working directory abstraction
		682	natively, the case "[$wd, "."]" as $srcpath is specialcased -
		683	instead of failing, "rename" is called on the absolute path of $wd.
		684
		685	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		686	Basically a version of "aio_rename" with an additional $flags
		687	argument. Calling this with "$flags=0" is the same as calling
		688	"aio_rename".
		689
		690	Non-zero flags are currently only supported on GNU/Linux systems
		691	that support renameat2. Other systems fail with "ENOSYS" in this
		692	case.
		693
		694	The following constants are available (missing ones are, as usual
		695	0), see renameat2(2) for details:
		696
		697	"IO::AIO::RENAME_NOREPLACE", "IO::AIO::RENAME_EXCHANGE" and
		698	"IO::AIO::RENAME_WHITEOUT".
706		699
707	aio_mkdir $pathname, $mode, $callback->($status)	700	aio_mkdir $pathname, $mode, $callback->($status)
708	Asynchronously mkdir (create) a directory and call the callback with	701	Asynchronously mkdir (create) a directory and call the callback with
709	the result code. $mode will be modified by the umask at the time the	702	the result code. $mode will be modified by the umask at the time the
710	request is executed, so do not change your umask.	703	request is executed, so do not change your umask.
711		704
712	aio_rmdir $pathname, $callback->($status)	705	aio_rmdir $pathname, $callback->($status)
713	Asynchronously rmdir (delete) a directory and call the callback with	706	Asynchronously rmdir (delete) a directory and call the callback with
714	the result code.	707	the result code.
715		708
		709	On systems that support the AIO::WD working directory abstraction
		710	natively, the case "[$wd, "."]" is specialcased - instead of
		711	failing, "rmdir" is called on the absolute path of $wd.
		712
716	aio_readdir $pathname, $callback->($entries)	713	aio_readdir $pathname, $callback->($entries)
717	Unlike the POSIX call of the same name, "aio_readdir" reads an	714	Unlike the POSIX call of the same name, "aio_readdir" reads an
718	entire directory (i.e. opendir + readdir + closedir). The entries	715	entire directory (i.e. opendir + readdir + closedir). The entries
719	will not be sorted, and will NOT include the "." and ".." entries.	716	will not be sorted, and will NOT include the "." and ".." entries.
720		717
…		…
729	The flags are a combination of the following constants, ORed	726	The flags are a combination of the following constants, ORed
730	together (the flags will also be passed to the callback, possibly	727	together (the flags will also be passed to the callback, possibly
731	modified):	728	modified):
732		729
733	IO::AIO::READDIR_DENTS	730	IO::AIO::READDIR_DENTS
734	When this flag is off, then the callback gets an arrayref	731	Normally the callback gets an arrayref consisting of names only
735	consisting of names only (as with "aio_readdir"), otherwise it	732	(as with "aio_readdir"). If this flag is set, then the callback
736	gets an arrayref with "[$name, $type, $inode]" arrayrefs, each	733	gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
737	describing a single directory entry in more detail.	734	describing a single directory entry in more detail:
738		735
739	$name is the name of the entry.	736	$name is the name of the entry.
740		737
741	$type is one of the "IO::AIO::DT_xxx" constants:	738	$type is one of the "IO::AIO::DT_xxx" constants:
742		739
743	"IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",	740	"IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",
744	"IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",	741	"IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",
745	"IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".	742	"IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
746		743
747	"IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If	744	"IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If
748	you need to know, you have to run stat yourself. Also, for speed	745	you need to know, you have to run stat yourself. Also, for
749	reasons, the $type scalars are read-only: you can not modify	746	speed/memory reasons, the $type scalars are read-only: you must
750	them.	747	not modify them.
751		748
752	$inode is the inode number (which might not be exact on systems	749	$inode is the inode number (which might not be exact on systems
753	with 64 bit inode numbers and 32 bit perls). This field has	750	with 64 bit inode numbers and 32 bit perls). This field has
754	unspecified content on systems that do not deliver the inode	751	unspecified content on systems that do not deliver the inode
755	information.	752	information.
…		…
767	of which names with short names are tried first.	764	of which names with short names are tried first.
768		765
769	IO::AIO::READDIR_STAT_ORDER	766	IO::AIO::READDIR_STAT_ORDER
770	When this flag is set, then the names will be returned in an	767	When this flag is set, then the names will be returned in an
771	order suitable for stat()'ing each one. That is, when you plan	768	order suitable for stat()'ing each one. That is, when you plan
772	to stat() all files in the given directory, then the returned	769	to stat() most or all files in the given directory, then the
773	order will likely be fastest.	770	returned order will likely be faster.
774		771
775	If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are	772	If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
776	specified, then the likely dirs come first, resulting in a less	773	specified, then the likely dirs come first, resulting in a less
777	optimal stat order.	774	optimal stat order for stat'ing all entries, but likely a more
		775	optimal order for finding subdirectories.
778		776
779	IO::AIO::READDIR_FOUND_UNKNOWN	777	IO::AIO::READDIR_FOUND_UNKNOWN
780	This flag should not be set when calling "aio_readdirx".	778	This flag should not be set when calling "aio_readdirx".
781	Instead, it is being set by "aio_readdirx", when any of the	779	Instead, it is being set by "aio_readdirx", when any of the
782	$type's found were "IO::AIO::DT_UNKNOWN". The absence of this	780	$type's found were "IO::AIO::DT_UNKNOWN". The absence of this
783	flag therefore indicates that all $type's are known, which can	781	flag therefore indicates that all $type's are known, which can
784	be used to speed up some algorithms.	782	be used to speed up some algorithms.
785		783
		784	aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		785	Opens, reads and closes the given file. The data is put into $data,
		786	which is resized as required.
		787
		788	If $offset is negative, then it is counted from the end of the file.
		789
		790	If $length is zero, then the remaining length of the file is used.
		791	Also, in this case, the same limitations to modifying $data apply as
		792	when IO::AIO::mmap is used, i.e. it must only be modified in-place
		793	with "substr". If the size of the file is known, specifying a
		794	non-zero $length results in a performance advantage.
		795
		796	This request is similar to the older "aio_load" request, but since
		797	it is a single request, it might be more efficient to use.
		798
		799	Example: load /etc/passwd into $passwd.
		800
		801	my $passwd;
		802	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		803	$_[0] >= 0
		804	or die "/etc/passwd: $!\n";
		805
		806	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		807	print $passwd;
		808	};
		809	IO::AIO::flush;
		810
786	aio_load $pathname, $data, $callback->($status)	811	aio_load $pathname, $data, $callback->($status)
787	This is a composite request that tries to fully load the given file	812	This is a composite request that tries to fully load the given file
788	into memory. Status is the same as with aio_read.	813	into memory. Status is the same as with aio_read.
		814
		815	Using "aio_slurp" might be more efficient, as it is a single
		816	request.
789		817
790	aio_copy $srcpath, $dstpath, $callback->($status)	818	aio_copy $srcpath, $dstpath, $callback->($status)
791	Try to copy the file (directories not supported as either source	819	Try to copy the file (directories not supported as either source
792	or destination) from $srcpath to $dstpath and call the callback with	820	or destination) from $srcpath to $dstpath and call the callback with
793	a status of 0 (ok) or -1 (error, see $!).	821	a status of 0 (ok) or -1 (error, see $!).
		822
		823	Existing destination files will be truncated.
794		824
795	This is a composite request that creates the destination file with	825	This is a composite request that creates the destination file with
796	mode 0200 and copies the contents of the source file into it using	826	mode 0200 and copies the contents of the source file into it using
797	"aio_sendfile", followed by restoring atime, mtime, access mode and	827	"aio_sendfile", followed by restoring atime, mtime, access mode and
798	uid/gid, in that order.	828	uid/gid, in that order.
…		…
815	to efficiently separate the entries of directory $path into two sets	845	to efficiently separate the entries of directory $path into two sets
816	of names, directories you can recurse into (directories), and ones	846	of names, directories you can recurse into (directories), and ones
817	you cannot recurse into (everything else, including symlinks to	847	you cannot recurse into (everything else, including symlinks to
818	directories).	848	directories).
819		849
820	"aio_scandir" is a composite request that creates of many sub	850	"aio_scandir" is a composite request that generates many sub
821	requests_ $maxreq specifies the maximum number of outstanding aio	851	requests. $maxreq specifies the maximum number of outstanding aio
822	requests that this function generates. If it is "<= 0", then a	852	requests that this function generates. If it is "<= 0", then a
823	suitable default will be chosen (currently 4).	853	suitable default will be chosen (currently 4).
824		854
825	On error, the callback is called without arguments, otherwise it	855	On error, the callback is called without arguments, otherwise it
826	receives two array-refs with path-relative entry names.	856	receives two array-refs with path-relative entry names.
…		…
873	Delete a directory tree starting (and including) $path, return the	903	Delete a directory tree starting (and including) $path, return the
874	status of the final "rmdir" only. This is a composite request that	904	status of the final "rmdir" only. This is a composite request that
875	uses "aio_scandir" to recurse into and rmdir directories, and unlink	905	uses "aio_scandir" to recurse into and rmdir directories, and unlink
876	everything else.	906	everything else.
877		907
		908	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		909	aio_ioctl $fh, $request, $buf, $callback->($status)
		910	These work just like the "fcntl" and "ioctl" built-in functions,
		911	except they execute asynchronously and pass the return value to the
		912	callback.
		913
		914	Both calls can be used for a lot of things, some of which make more
		915	sense to run asynchronously in their own thread, while some others
		916	make less sense. For example, calls that block waiting for external
		917	events, such as locking, will also lock down an I/O thread while it
		918	is waiting, which can deadlock the whole I/O system. At the same
		919	time, there might be no alternative to using a thread to wait.
		920
		921	So in general, you should only use these calls for things that do
		922	(filesystem) I/O, not for things that wait for other events
		923	(network, other processes), although if you are careful and know
		924	what you are doing, you still can.
		925
		926	The following constants are available and can be used for normal
		927	"ioctl" and "fcntl" as well (missing ones are, as usual 0):
		928
		929	"F_DUPFD_CLOEXEC",
		930
		931	"F_OFD_GETLK", "F_OFD_SETLK", "F_OFD_GETLKW",
		932
		933	"FIFREEZE", "FITHAW", "FITRIM", "FICLONE", "FICLONERANGE",
		934	"FIDEDUPERANGE".
		935
		936	"F_ADD_SEALS", "F_GET_SEALS", "F_SEAL_SEAL", "F_SEAL_SHRINK",
		937	"F_SEAL_GROW" and "F_SEAL_WRITE".
		938
		939	"FS_IOC_GETFLAGS", "FS_IOC_SETFLAGS", "FS_IOC_GETVERSION",
		940	"FS_IOC_SETVERSION", "FS_IOC_FIEMAP".
		941
		942	"FS_IOC_FSGETXATTR", "FS_IOC_FSSETXATTR",
		943	"FS_IOC_SET_ENCRYPTION_POLICY", "FS_IOC_GET_ENCRYPTION_PWSALT",
		944	"FS_IOC_GET_ENCRYPTION_POLICY", "FS_KEY_DESCRIPTOR_SIZE".
		945
		946	"FS_SECRM_FL", "FS_UNRM_FL", "FS_COMPR_FL", "FS_SYNC_FL",
		947	"FS_IMMUTABLE_FL", "FS_APPEND_FL", "FS_NODUMP_FL", "FS_NOATIME_FL",
		948	"FS_DIRTY_FL", "FS_COMPRBLK_FL", "FS_NOCOMP_FL", "FS_ENCRYPT_FL",
		949	"FS_BTREE_FL", "FS_INDEX_FL", "FS_JOURNAL_DATA_FL", "FS_NOTAIL_FL",
		950	"FS_DIRSYNC_FL", "FS_TOPDIR_FL", "FS_FL_USER_MODIFIABLE".
		951
		952	"FS_XFLAG_REALTIME", "FS_XFLAG_PREALLOC", "FS_XFLAG_IMMUTABLE",
		953	"FS_XFLAG_APPEND", "FS_XFLAG_SYNC", "FS_XFLAG_NOATIME",
		954	"FS_XFLAG_NODUMP", "FS_XFLAG_RTINHERIT", "FS_XFLAG_PROJINHERIT",
		955	"FS_XFLAG_NOSYMLINKS", "FS_XFLAG_EXTSIZE", "FS_XFLAG_EXTSZINHERIT",
		956	"FS_XFLAG_NODEFRAG", "FS_XFLAG_FILESTREAM", "FS_XFLAG_DAX",
		957	"FS_XFLAG_HASATTR",
		958
		959	"BLKROSET", "BLKROGET", "BLKRRPART", "BLKGETSIZE", "BLKFLSBUF",
		960	"BLKRASET", "BLKRAGET", "BLKFRASET", "BLKFRAGET", "BLKSECTSET",
		961	"BLKSECTGET", "BLKSSZGET", "BLKBSZGET", "BLKBSZSET", "BLKGETSIZE64",
		962
878	aio_sync $callback->($status)	963	aio_sync $callback->($status)
879	Asynchronously call sync and call the callback when finished.	964	Asynchronously call sync and call the callback when finished.
880		965
881	aio_fsync $fh, $callback->($status)	966	aio_fsync $fh, $callback->($status)
882	Asynchronously call fsync on the given filehandle and call the	967	Asynchronously call fsync on the given filehandle and call the
…		…
918	Future versions of this function might fall back to other methods	1003	Future versions of this function might fall back to other methods
919	when "fsync" on the directory fails (such as calling "sync").	1004	when "fsync" on the directory fails (such as calling "sync").
920		1005
921	Passes 0 when everything went ok, and -1 on error.	1006	Passes 0 when everything went ok, and -1 on error.
922		1007
923	aio_msync $scalar, $offset = 0, $length = undef, flags = 0,	1008	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC,
924	$callback->($status)	1009	$callback->($status)
925	This is a rather advanced IO::AIO call, which only works on	1010	This is a rather advanced IO::AIO call, which only works on
926	mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it	1011	mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
927	also works on data scalars managed by the Sys::Mmap or Mmap modules,	1012	also works on data scalars managed by the Sys::Mmap or Mmap modules,
928	note that the scalar must only be modified in-place while an aio	1013	note that the scalar must only be modified in-place while an aio
…		…
930		1015
931	It calls the "msync" function of your OS, if available, with the	1016	It calls the "msync" function of your OS, if available, with the
932	memory area starting at $offset in the string and ending $length	1017	memory area starting at $offset in the string and ending $length
933	bytes later. If $length is negative, counts from the end, and if	1018	bytes later. If $length is negative, counts from the end, and if
934	$length is "undef", then it goes till the end of the string. The	1019	$length is "undef", then it goes till the end of the string. The
935	flags can be a combination of "IO::AIO::MS_ASYNC",	1020	flags can be either "IO::AIO::MS_ASYNC" or "IO::AIO::MS_SYNC", plus
936	"IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC".	1021	an optional "IO::AIO::MS_INVALIDATE".
937		1022
938	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,	1023	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
939	$callback->($status)	1024	$callback->($status)
940	This is a rather advanced IO::AIO call, which works best on	1025	This is a rather advanced IO::AIO call, which works best on
941	mmap(2)ed scalars.	1026	mmap(2)ed scalars.
942		1027
943	It touches (reads or writes) all memory pages in the specified range	1028	It touches (reads or writes) all memory pages in the specified range
944	inside the scalar. All caveats and parameters are the same as for	1029	inside the scalar. All caveats and parameters are the same as for
945	"aio_msync", above, except for flags, which must be either 0 (which	1030	"aio_msync", above, except for flags, which must be either 0 (which
946	reads all pages and ensures they are instantiated) or	1031	reads all pages and ensures they are instantiated) or
947	"IO::AIO::MT_MODIFY", which modifies the memory page s(by reading	1032	"IO::AIO::MT_MODIFY", which modifies the memory pages (by reading
948	and writing an octet from it, which dirties the page).	1033	and writing an octet from it, which dirties the page).
949		1034
950	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1035	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
951	This is a rather advanced IO::AIO call, which works best on	1036	This is a rather advanced IO::AIO call, which works best on
952	mmap(2)ed scalars.	1037	mmap(2)ed scalars.
…		…
972	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;	1057	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
973	aio_mlock $data; # mlock in background	1058	aio_mlock $data; # mlock in background
974		1059
975	aio_mlockall $flags, $callback->($status)	1060	aio_mlockall $flags, $callback->($status)
976	Calls the "mlockall" function with the given $flags (a combination	1061	Calls the "mlockall" function with the given $flags (a combination
977	of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE").	1062	of "IO::AIO::MCL_CURRENT", "IO::AIO::MCL_FUTURE" and
		1063	"IO::AIO::MCL_ONFAULT").
978		1064
979	On systems that do not implement "mlockall", this function returns	1065	On systems that do not implement "mlockall", this function returns
980	-1 and sets errno to "ENOSYS".	1066	-1 and sets errno to "ENOSYS". Similarly, flag combinations not
		1067	supported by the system result in a return value of -1 with errno
		1068	being set to "EINVAL".
981		1069
982	Note that the corresponding "munlockall" is synchronous and is	1070	Note that the corresponding "munlockall" is synchronous and is
983	documented under "MISCELLANEOUS FUNCTIONS".	1071	documented under "MISCELLANEOUS FUNCTIONS".
984		1072
985	Example: asynchronously lock all current and future pages into	1073	Example: asynchronously lock all current and future pages into
…		…
1027	"IO::AIO::FIEMAP_EXTENT_DATA_INLINE",	1115	"IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
1028	"IO::AIO::FIEMAP_EXTENT_DATA_TAIL",	1116	"IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
1029	"IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"	1117	"IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
1030	or "IO::AIO::FIEMAP_EXTENT_SHARED".	1118	or "IO::AIO::FIEMAP_EXTENT_SHARED".
1031		1119
1032	At the time of this writing (Linux 3.2), this requets is unreliable	1120	At the time of this writing (Linux 3.2), this request is unreliable
1033	unless $count is "undef", as the kernel has all sorts of bugs	1121	unless $count is "undef", as the kernel has all sorts of bugs
1034	preventing it to return all extents of a range for files with large	1122	preventing it to return all extents of a range for files with a
1035	number of extents. The code works around all these issues if $count	1123	large number of extents. The code (only) works around all these
1036	is undef.	1124	issues if $count is "undef".
1037		1125
1038	aio_group $callback->(...)	1126	aio_group $callback->(...)
1039	This is a very special aio request: Instead of doing something, it	1127	This is a very special aio request: Instead of doing something, it
1040	is a container for other aio requests, which is useful if you want	1128	is a container for other aio requests, which is useful if you want
1041	to bundle many requests into a single, composite, request with a	1129	to bundle many requests into a single, composite, request with a
…		…
1121	aio_stat [$etcdir, "passwd"], sub {	1209	aio_stat [$etcdir, "passwd"], sub {
1122	# yay	1210	# yay
1123	};	1211	};
1124	};	1212	};
1125		1213
1126	That "aio_wd" is a request and not a normal function shows that creating	1214	The fact that "aio_wd" is a request and not a normal function shows that
1127	an IO::AIO::WD object is itself a potentially blocking operation, which	1215	creating an IO::AIO::WD object is itself a potentially blocking
1128	is why it is done asynchronously.	1216	operation, which is why it is done asynchronously.
1129		1217
1130	To stat the directory obtained with "aio_wd" above, one could write	1218	To stat the directory obtained with "aio_wd" above, one could write
1131	either of the following three request calls:	1219	either of the following three request calls:
1132		1220
1133	aio_lstat "/etc" , sub { ... # pathname as normal string	1221	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1150	There are some caveats: when directories get renamed (or deleted), the	1238	There are some caveats: when directories get renamed (or deleted), the
1151	pathname string doesn't change, so will point to the new directory (or	1239	pathname string doesn't change, so will point to the new directory (or
1152	nowhere at all), while the directory fd, if available on the system,	1240	nowhere at all), while the directory fd, if available on the system,
1153	will still point to the original directory. Most functions accepting a	1241	will still point to the original directory. Most functions accepting a
1154	pathname will use the directory fd on newer systems, and the string on	1242	pathname will use the directory fd on newer systems, and the string on
1155	older systems. Some functions (such as realpath) will always rely on the	1243	older systems. Some functions (such as "aio_realpath") will always rely
1156	string form of the pathname.	1244	on the string form of the pathname.
1157		1245
1158	So this fucntionality is mainly useful to get some protection against	1246	So this functionality is mainly useful to get some protection against
1159	"chdir", to easily get an absolute path out of a relative path for	1247	"chdir", to easily get an absolute path out of a relative path for
1160	future reference, and to speed up doing many operations in the same	1248	future reference, and to speed up doing many operations in the same
1161	directory (e.g. when stat'ing all files in a directory).	1249	directory (e.g. when stat'ing all files in a directory).
1162		1250
1163	The following functions implement this working directory abstraction:	1251	The following functions implement this working directory abstraction:
…		…
1173	Since passing "undef" as working directory component of a pathname	1261	Since passing "undef" as working directory component of a pathname
1174	fails the request with "ENOENT", there is often no need for error	1262	fails the request with "ENOENT", there is often no need for error
1175	checking in the "aio_wd" callback, as future requests using the	1263	checking in the "aio_wd" callback, as future requests using the
1176	value will fail in the expected way.	1264	value will fail in the expected way.
1177		1265
1178	If this call isn't available because your OS lacks it or it couldn't
1179	be detected, it will be emulated by calling "fsync" instead.
1180
1181	IO::AIO::CWD	1266	IO::AIO::CWD
1182	This is a compiletime constant (object) that represents the process	1267	This is a compile time constant (object) that represents the process
1183	current working directory.	1268	current working directory.
1184		1269
1185	Specifying this object as working directory object for a pathname is	1270	Specifying this object as working directory object for a pathname is
1186	as if the pathname would be specified directly, without a directory	1271	as if the pathname would be specified directly, without a directory
1187	object, e.g., these calls are functionally identical:	1272	object. For example, these calls are functionally identical:
1188		1273
1189	aio_stat "somefile", sub { ... };	1274	aio_stat "somefile", sub { ... };
1190	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1275	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1276
		1277	To recover the path associated with an IO::AIO::WD object, you can use
		1278	"aio_realpath":
		1279
		1280	aio_realpath $wd, sub {
		1281	warn "path is $_[0]\n";
		1282	};
		1283
		1284	Currently, "aio_statvfs" always, and "aio_rename" and "aio_rmdir"
		1285	sometimes, fall back to using an absolue path.
1191		1286
1192	IO::AIO::REQ CLASS	1287	IO::AIO::REQ CLASS
1193	All non-aggregate "aio_*" functions return an object of this class when	1288	All non-aggregate "aio_*" functions return an object of this class when
1194	called in non-void context.	1289	called in non-void context.
1195		1290
…		…
1347	results.	1442	results.
1348		1443
1349	See "poll_cb" for an example.	1444	See "poll_cb" for an example.
1350		1445
1351	IO::AIO::poll_cb	1446	IO::AIO::poll_cb
1352	Process some outstanding events on the result pipe. You have to call	1447	Process some requests that have reached the result phase (i.e. they
		1448	have been executed but the results are not yet reported). You have
		1449	to call this "regularly" to finish outstanding requests.
		1450
1353	this regularly. Returns 0 if all events could be processed (or there	1451	Returns 0 if all events could be processed (or there were no events
1354	were no events to process), or -1 if it returned earlier for	1452	to process), or -1 if it returned earlier for whatever reason.
1355	whatever reason. Returns immediately when no events are outstanding.	1453	Returns immediately when no events are outstanding. The amount of
1356	The amount of events processed depends on the settings of	1454	events processed depends on the settings of "IO::AIO::max_poll_req",
1357	"IO::AIO::max_poll_req" and "IO::AIO::max_poll_time".	1455	"IO::AIO::max_poll_time" and "IO::AIO::max_outstanding".
1358		1456
1359	If not all requests were processed for whatever reason, the	1457	If not all requests were processed for whatever reason, the poll
1360	filehandle will still be ready when "poll_cb" returns, so normally	1458	file descriptor will still be ready when "poll_cb" returns, so
1361	you don't have to do anything special to have it called later.	1459	normally you don't have to do anything special to have it called
		1460	later.
1362		1461
1363	Apart from calling "IO::AIO::poll_cb" when the event filehandle	1462	Apart from calling "IO::AIO::poll_cb" when the event filehandle
1364	becomes ready, it can be beneficial to call this function from loops	1463	becomes ready, it can be beneficial to call this function from loops
1365	which submit a lot of requests, to make sure the results get	1464	which submit a lot of requests, to make sure the results get
1366	processed when they become available and not just when the loop is	1465	processed when they become available and not just when the loop is
…		…
1374	Event->io (fd => IO::AIO::poll_fileno,	1473	Event->io (fd => IO::AIO::poll_fileno,
1375	poll => 'r', async => 1,	1474	poll => 'r', async => 1,
1376	cb => \&IO::AIO::poll_cb);	1475	cb => \&IO::AIO::poll_cb);
1377		1476
1378	IO::AIO::poll_wait	1477	IO::AIO::poll_wait
1379	If there are any outstanding requests and none of them in the result	1478	Wait until either at least one request is in the result phase or no
1380	phase, wait till the result filehandle becomes ready for reading	1479	requests are outstanding anymore.
1381	(simply does a "select" on the filehandle. This is useful if you	1480
1382	want to synchronously wait for some requests to finish).	1481	This is useful if you want to synchronously wait for some requests
		1482	to become ready, without actually handling them.
1383		1483
1384	See "nreqs" for an example.	1484	See "nreqs" for an example.
1385		1485
1386	IO::AIO::poll	1486	IO::AIO::poll
1387	Waits until some requests have been handled.	1487	Waits until some requests have been handled.
…		…
1396		1496
1397	Strictly equivalent to:	1497	Strictly equivalent to:
1398		1498
1399	IO::AIO::poll_wait, IO::AIO::poll_cb	1499	IO::AIO::poll_wait, IO::AIO::poll_cb
1400	while IO::AIO::nreqs;	1500	while IO::AIO::nreqs;
		1501
		1502	This function can be useful at program aborts, to make sure
		1503	outstanding I/O has been done ("IO::AIO" uses an "END" block which
		1504	already calls this function on normal exits), or when you are merely
		1505	using "IO::AIO" for its more advanced functions, rather than for
		1506	async I/O, e.g.:
		1507
		1508	my ($dirs, $nondirs);
		1509	IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
		1510	IO::AIO::flush;
		1511	# $dirs, $nondirs are now set
1401		1512
1402	IO::AIO::max_poll_reqs $nreqs	1513	IO::AIO::max_poll_reqs $nreqs
1403	IO::AIO::max_poll_time $seconds	1514	IO::AIO::max_poll_time $seconds
1404	These set the maximum number of requests (default 0, meaning	1515	These set the maximum number of requests (default 0, meaning
1405	infinity) that are being processed by "IO::AIO::poll_cb" in one	1516	infinity) that are being processed by "IO::AIO::poll_cb" in one
…		…
1495	no longer exceeded.	1606	no longer exceeded.
1496		1607
1497	In other words, this setting does not enforce a queue limit, but can	1608	In other words, this setting does not enforce a queue limit, but can
1498	be used to make poll functions block if the limit is exceeded.	1609	be used to make poll functions block if the limit is exceeded.
1499		1610
1500	This is a very bad function to use in interactive programs because	1611	This is a bad function to use in interactive programs because it
1501	it blocks, and a bad way to reduce concurrency because it is	1612	blocks, and a bad way to reduce concurrency because it is inexact.
1502	inexact: Better use an "aio_group" together with a feed callback.	1613	If you need to issue many requests without being able to call a poll
		1614	function on demand, it is better to use an "aio_group" together with
		1615	a feed callback.
1503		1616
1504	It's main use is in scripts without an event loop - when you want to	1617	Its main use is in scripts without an event loop - when you want to
1505	stat a lot of files, you can write somehting like this:	1618	stat a lot of files, you can write something like this:
1506		1619
1507	IO::AIO::max_outstanding 32;	1620	IO::AIO::max_outstanding 32;
1508		1621
1509	for my $path (...) {	1622	for my $path (...) {
1510	aio_stat $path , ...;	1623	aio_stat $path , ...;
…		…
1512	}	1625	}
1513		1626
1514	IO::AIO::flush;	1627	IO::AIO::flush;
1515		1628
1516	The call to "poll_cb" inside the loop will normally return	1629	The call to "poll_cb" inside the loop will normally return
1517	instantly, but as soon as more thna 32 reqeusts are in-flight, it	1630	instantly, allowing the loop to progress, but as soon as more than
1518	will block until some requests have been handled. This keeps the	1631	32 requests are in-flight, it will block until some requests have
1519	loop from pushing a large number of "aio_stat" requests onto the	1632	been handled. This keeps the loop from pushing a large number of
1520	queue.	1633	"aio_stat" requests onto the queue (which, with many paths to stat,
		1634	can use up a lot of memory).
1521		1635
1522	The default value for "max_outstanding" is very large, so there is	1636	The default value for "max_outstanding" is very large, so there is
1523	no practical limit on the number of outstanding requests.	1637	no practical limit on the number of outstanding requests.
1524		1638
1525	STATISTICAL INFORMATION	1639	STATISTICAL INFORMATION
…		…
1539		1653
1540	IO::AIO::npending	1654	IO::AIO::npending
1541	Returns the number of requests currently in the pending state	1655	Returns the number of requests currently in the pending state
1542	(executed, but not yet processed by poll_cb).	1656	(executed, but not yet processed by poll_cb).
1543		1657
		1658	SUBSECOND STAT TIME ACCESS
		1659	Both "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" functions can
		1660	generally find access/modification and change times with subsecond time
		1661	accuracy of the system supports it, but perl's built-in functions only
		1662	return the integer part.
		1663
		1664	The following functions return the timestamps of the most recent stat
		1665	with subsecond precision on most systems and work both after
		1666	"aio_stat"/"aio_lstat" and perl's "stat"/"lstat" calls. Their return
		1667	value is only meaningful after a successful "stat"/"lstat" call, or
		1668	during/after a successful "aio_stat"/"aio_lstat" callback.
		1669
		1670	This is similar to the Time::HiRes "stat" functions, but can return full
		1671	resolution without rounding and work with standard perl "stat",
		1672	alleviating the need to call the special "Time::HiRes" functions, which
		1673	do not act like their perl counterparts.
		1674
		1675	On operating systems or file systems where subsecond time resolution is
		1676	not supported or could not be detected, a fractional part of 0 is
		1677	returned, so it is always safe to call these functions.
		1678
		1679	$seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime,
		1680	IO::AIO::st_btime
		1681	Return the access, modication, change or birth time, respectively,
		1682	including fractional part. Due to the limited precision of floating
		1683	point, the accuracy on most platforms is only a bit better than
		1684	milliseconds for times around now - see the nsec function family,
		1685	below, for full accuracy.
		1686
		1687	File birth time is only available when the OS and perl support it
		1688	(on FreeBSD and NetBSD at the time of this writing, although support
		1689	is adaptive, so if your OS/perl gains support, IO::AIO can take
		1690	advantage of it). On systems where it isn't available, 0 is
		1691	currently returned, but this might change to "undef" in a future
		1692	version.
		1693
		1694	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		1695	Returns access, modification, change and birth time all in one go,
		1696	and maybe more times in the future version.
		1697
		1698	$nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec,
		1699	IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		1700	Return the fractional access, modifcation, change or birth time, in
		1701	nanoseconds, as an integer in the range 0 to 999999999.
		1702
		1703	Note that no accessors are provided for access, modification and
		1704	change times - you need to get those from "stat _" if required ("int
		1705	IO::AIO::st_atime" and so on will not generally give you the
		1706	correct value).
		1707
		1708	$seconds = IO::AIO::st_btimesec
		1709	The (integral) seconds part of the file birth time, if available.
		1710
		1711	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		1712	Like the functions above, but returns all four times in one go (and
		1713	maybe more in future versions).
		1714
		1715	$counter = IO::AIO::st_gen
		1716	Returns the generation counter (in practice this is just a random
		1717	number) of the file. This is only available on platforms which have
		1718	this member in their "struct stat" (most BSDs at the time of this
		1719	writing) and generally only to the root usert. If unsupported, 0 is
		1720	returned, but this might change to "undef" in a future version.
		1721
		1722	Example: print the high resolution modification time of /etc, using
		1723	"stat", and "IO::AIO::aio_stat".
		1724
		1725	if (stat "/etc") {
		1726	printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
		1727	}
		1728
		1729	IO::AIO::aio_stat "/etc", sub {
		1730	$_[0]
		1731	and return;
		1732
		1733	printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
		1734	};
		1735
		1736	IO::AIO::flush;
		1737
		1738	Output of the awbove on my system, showing reduced and full accuracy:
		1739
		1740	stat(/etc) mtime: 1534043702.020808
		1741	aio_stat(/etc) mtime: 1534043702.020807792
		1742
1544	MISCELLANEOUS FUNCTIONS	1743	MISCELLANEOUS FUNCTIONS
1545	IO::AIO implements some functions that might be useful, but are not	1744	IO::AIO implements some functions that are useful when you want to use
1546	asynchronous.	1745	some "Advanced I/O" function not available to in Perl, without going the
		1746	"Asynchronous I/O" route. Many of these have an asynchronous "aio_*"
		1747	counterpart.
		1748
		1749	$retval = IO::AIO::fexecve $fh, $argv, $envp
		1750	A more-or-less direct equivalent to the POSIX "fexecve" functions,
		1751	which allows you to specify the program to be executed via a file
		1752	descriptor (or handle). Returns -1 and sets errno to "ENOSYS" if not
		1753	available.
		1754
		1755	$retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data =
		1756	undef
		1757	Calls the GNU/Linux mount syscall with the given arguments. All
		1758	except $flags are strings, and if $data is "undef", a "NULL" will be
		1759	passed.
		1760
		1761	The following values for $flags are available:
		1762
		1763	"IO::AIO::MS_RDONLY", "IO::AIO::MS_NOSUID", "IO::AIO::MS_NODEV",
		1764	"IO::AIO::MS_NOEXEC", "IO::AIO::MS_SYNCHRONOUS",
		1765	"IO::AIO::MS_REMOUNT", "IO::AIO::MS_MANDLOCK",
		1766	"IO::AIO::MS_DIRSYNC", "IO::AIO::MS_NOATIME",
		1767	"IO::AIO::MS_NODIRATIME", "IO::AIO::MS_BIND", "IO::AIO::MS_MOVE",
		1768	"IO::AIO::MS_REC", "IO::AIO::MS_SILENT", "IO::AIO::MS_POSIXACL",
		1769	"IO::AIO::MS_UNBINDABLE", "IO::AIO::MS_PRIVATE",
		1770	"IO::AIO::MS_SLAVE", "IO::AIO::MS_SHARED", "IO::AIO::MS_RELATIME",
		1771	"IO::AIO::MS_KERNMOUNT", "IO::AIO::MS_I_VERSION",
		1772	"IO::AIO::MS_STRICTATIME", "IO::AIO::MS_LAZYTIME",
		1773	"IO::AIO::MS_ACTIVE", "IO::AIO::MS_NOUSER", "IO::AIO::MS_RMT_MASK",
		1774	"IO::AIO::MS_MGC_VAL" and "IO::AIO::MS_MGC_MSK".
		1775
		1776	$retval = IO::AIO::umount $path, $flags = 0
		1777	Invokes the GNU/Linux "umount" or "umount2" syscalls. Always calls
		1778	"umount" if $flags is 0, otherwqise always tries to call "umount2".
		1779
		1780	The following $flags are available:
		1781
		1782	"IO::AIO::MNT_FORCE", "IO::AIO::MNT_DETACH", "IO::AIO::MNT_EXPIRE"
		1783	and "IO::AIO::UMOUNT_NOFOLLOW".
		1784
		1785	$numfd = IO::AIO::get_fdlimit
		1786	Tries to find the current file descriptor limit and returns it, or
		1787	"undef" and sets $! in case of an error. The limit is one larger
		1788	than the highest valid file descriptor number.
		1789
		1790	IO::AIO::min_fdlimit [$numfd]
		1791	Try to increase the current file descriptor limit(s) to at least
		1792	$numfd by changing the soft or hard file descriptor resource limit.
		1793	If $numfd is missing, it will try to set a very high limit, although
		1794	this is not recommended when you know the actual minimum that you
		1795	require.
		1796
		1797	If the limit cannot be raised enough, the function makes a
		1798	best-effort attempt to increase the limit as much as possible, using
		1799	various tricks, while still failing. You can query the resulting
		1800	limit using "IO::AIO::get_fdlimit".
		1801
		1802	If an error occurs, returns "undef" and sets $!, otherwise returns
		1803	true.
1547		1804
1548	IO::AIO::sendfile $ofh, $ifh, $offset, $count	1805	IO::AIO::sendfile $ofh, $ifh, $offset, $count
1549	Calls the "eio_sendfile_sync" function, which is like	1806	Calls the "eio_sendfile_sync" function, which is like
1550	"aio_sendfile", but is blocking (this makes most sense if you know	1807	"aio_sendfile", but is blocking (this makes most sense if you know
1551	the input data is likely cached already and the output filehandle is	1808	the input data is likely cached already and the output filehandle is
…		…
1568	details). The following advice constants are available:	1825	details). The following advice constants are available:
1569	"IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",	1826	"IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1570	"IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",	1827	"IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1571	"IO::AIO::MADV_DONTNEED".	1828	"IO::AIO::MADV_DONTNEED".
1572		1829
		1830	If $offset is negative, counts from the end. If $length is negative,
		1831	the remaining length of the $scalar is used. If possible, $length
		1832	will be reduced to fit into the $scalar.
		1833
1573	On systems that do not implement "posix_madvise", this function	1834	On systems that do not implement "posix_madvise", this function
1574	returns ENOSYS, otherwise the return value of "posix_madvise".	1835	returns ENOSYS, otherwise the return value of "posix_madvise".
1575		1836
1576	IO::AIO::mprotect $scalar, $offset, $len, $protect	1837	IO::AIO::mprotect $scalar, $offset, $len, $protect
1577	Simply calls the "mprotect" function on the preferably AIO::mmap'ed	1838	Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1578	$scalar (see its manpage for details). The following protect	1839	$scalar (see its manpage for details). The following protect
1579	constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",	1840	constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1580	"IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".	1841	"IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1581		1842
		1843	If $offset is negative, counts from the end. If $length is negative,
		1844	the remaining length of the $scalar is used. If possible, $length
		1845	will be reduced to fit into the $scalar.
		1846
1582	On systems that do not implement "mprotect", this function returns	1847	On systems that do not implement "mprotect", this function returns
1583	ENOSYS, otherwise the return value of "mprotect".	1848	ENOSYS, otherwise the return value of "mprotect".
1584		1849
1585	IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	1850	IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1586	Memory-maps a file (or anonymous memory range) and attaches it to	1851	Memory-maps a file (or anonymous memory range) and attaches it to
1587	the given $scalar, which will act like a string scalar. Returns true	1852	the given $scalar, which will act like a string scalar. Returns true
1588	on success, and false otherwise.	1853	on success, and false otherwise.
1589		1854
		1855	The scalar must exist, but its contents do not matter - this means
		1856	you cannot use a nonexistant array or hash element. When in doubt,
		1857	"undef" the scalar first.
		1858
1590	The only operations allowed on the scalar are "substr"/"vec" that	1859	The only operations allowed on the mmapped scalar are
1591	don't change the string length, and most read-only operations such	1860	"substr"/"vec", which don't change the string length, and most
1592	as copying it or searching it with regexes and so on.	1861	read-only operations such as copying it or searching it with regexes
		1862	and so on.
1593		1863
1594	Anything else is unsafe and will, at best, result in memory leaks.	1864	Anything else is unsafe and will, at best, result in memory leaks.
1595		1865
1596	The memory map associated with the $scalar is automatically removed	1866	The memory map associated with the $scalar is automatically removed
1597	when the $scalar is destroyed, or when the "IO::AIO::mmap" or	1867	when the $scalar is undef'd or destroyed, or when the
1598	"IO::AIO::munmap" functions are called.	1868	"IO::AIO::mmap" or "IO::AIO::munmap" functions are called on it.
1599		1869
1600	This calls the "mmap"(2) function internally. See your system's	1870	This calls the "mmap"(2) function internally. See your system's
1601	manual page for details on the $length, $prot and $flags parameters.	1871	manual page for details on the $length, $prot and $flags parameters.
1602		1872
1603	The $length must be larger than zero and smaller than the actual	1873	The $length must be larger than zero and smaller than the actual
…		…
1607	"IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or	1877	"IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1608	"IO::AIO::PROT_WRITE",	1878	"IO::AIO::PROT_WRITE",
1609		1879
1610	$flags can be a combination of "IO::AIO::MAP_SHARED" or	1880	$flags can be a combination of "IO::AIO::MAP_SHARED" or
1611	"IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when	1881	"IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1612	not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS"	1882	not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to
1613	(which is set to "MAP_ANON" if your system only provides this	1883	"MAP_ANON" if your system only provides this constant),
		1884	"IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE",
1614	constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",	1885	"IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK",
1615	"IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or	1886	"IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN",
1616	"IO::AIO::MAP_NONBLOCK"	1887	"IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_STACK",
		1888	"IO::AIO::MAP_FIXED_NOREPLACE", "IO::AIO::MAP_SHARED_VALIDATE",
		1889	"IO::AIO::MAP_SYNC" or "IO::AIO::MAP_UNINITIALIZED".
1617		1890
1618	If $fh is "undef", then a file descriptor of -1 is passed.	1891	If $fh is "undef", then a file descriptor of -1 is passed.
1619		1892
1620	$offset is the offset from the start of the file - it generally must	1893	$offset is the offset from the start of the file - it generally must
1621	be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.	1894	be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
…		…
1633		1906
1634	my $fast_md5 = md5 $data;	1907	my $fast_md5 = md5 $data;
1635		1908
1636	IO::AIO::munmap $scalar	1909	IO::AIO::munmap $scalar
1637	Removes a previous mmap and undefines the $scalar.	1910	Removes a previous mmap and undefines the $scalar.
		1911
		1912	IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[,
		1913	$new_address = 0]
		1914	Calls the Linux-specific mremap(2) system call. The $scalar must
		1915	have been mapped by "IO::AIO::mmap", and $flags must currently
		1916	either be 0 or "IO::AIO::MREMAP_MAYMOVE".
		1917
		1918	Returns true if successful, and false otherwise. If the underlying
		1919	mmapped region has changed address, then the true value has the
		1920	numerical value 1, otherwise it has the numerical value 0:
		1921
		1922	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		1923	or die "mremap: $!";
		1924
		1925	if ($success*1) {
		1926	warn "scalar has chanegd address in memory\n";
		1927	}
		1928
		1929	"IO::AIO::MREMAP_FIXED" and the $new_address argument are currently
		1930	implemented, but not supported and might go away in a future
		1931	version.
		1932
		1933	On systems where this call is not supported or is not emulated, this
		1934	call returns falls and sets $! to "ENOSYS".
		1935
		1936	IO::AIO::mlockall $flags
		1937	Calls the "eio_mlockall_sync" function, which is like
		1938	"aio_mlockall", but is blocking.
1638		1939
1639	IO::AIO::munlock $scalar, $offset = 0, $length = undef	1940	IO::AIO::munlock $scalar, $offset = 0, $length = undef
1640	Calls the "munlock" function, undoing the effects of a previous	1941	Calls the "munlock" function, undoing the effects of a previous
1641	"aio_mlock" call (see its description for details).	1942	"aio_mlock" call (see its description for details).
1642		1943
1643	IO::AIO::munlockall	1944	IO::AIO::munlockall
1644	Calls the "munlockall" function.	1945	Calls the "munlockall" function.
1645		1946
1646	On systems that do not implement "munlockall", this function returns	1947	On systems that do not implement "munlockall", this function returns
1647	ENOSYS, otherwise the return value of "munlockall".	1948	ENOSYS, otherwise the return value of "munlockall".
		1949
		1950	$fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
		1951	Uses the GNU/Linux accept4(2) syscall, if available, to accept a
		1952	socket and return the new file handle on success, or sets $! and
		1953	returns "undef" on error.
		1954
		1955	The remote name of the new socket will be stored in $sockaddr, which
		1956	will be extended to allow for at least $sockaddr_maxlen octets. If
		1957	the socket name does not fit into $sockaddr_maxlen octets, this is
		1958	signaled by returning a longer string in $sockaddr, which might or
		1959	might not be truncated.
		1960
		1961	To accept name-less sockets, use "undef" for $sockaddr and 0 for
		1962	$sockaddr_maxlen.
		1963
		1964	The main reasons to use this syscall rather than portable accept(2)
		1965	are that you can specify "SOCK_NONBLOCK" and/or "SOCK_CLOEXEC" flags
		1966	and you can accept name-less sockets by specifying 0 for
		1967	$sockaddr_maxlen, which is sadly not possible with perl's interface
		1968	to "accept".
1648		1969
1649	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags	1970	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1650	Calls the GNU/Linux splice(2) syscall, if available. If $r_off or	1971	Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1651	$w_off are "undef", then "NULL" is passed for these, otherwise they	1972	$w_off are "undef", then "NULL" is passed for these, otherwise they
1652	should be the file offset.	1973	should be the file offset.
…		…
1659	"IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".	1980	"IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".
1660		1981
1661	See the splice(2) manpage for details.	1982	See the splice(2) manpage for details.
1662		1983
1663	IO::AIO::tee $r_fh, $w_fh, $length, $flags	1984	IO::AIO::tee $r_fh, $w_fh, $length, $flags
1664	Calls the GNU/Linux tee(2) syscall, see it's manpage and the	1985	Calls the GNU/Linux tee(2) syscall, see its manpage and the
1665	description for "IO::AIO::splice" above for details.	1986	description for "IO::AIO::splice" above for details.
		1987
		1988	$actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		1989	Attempts to query or change the pipe buffer size. Obviously works
		1990	only on pipes, and currently works only on GNU/Linux systems, and
		1991	fails with -1/"ENOSYS" everywhere else. If anybody knows how to
		1992	influence pipe buffer size on other systems, drop me a note.
		1993
		1994	($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		1995	This is a direct interface to the Linux pipe2(2) system call. If
		1996	$flags is missing or 0, then this should be the same as a call to
		1997	perl's built-in "pipe" function and create a new pipe, and works on
		1998	systems that lack the pipe2 syscall. On win32, this case invokes
		1999	"_pipe (..., 4096, O_BINARY)".
		2000
		2001	If $flags is non-zero, it tries to invoke the pipe2 system call with
		2002	the given flags (Linux 2.6.27, glibc 2.9).
		2003
		2004	On success, the read and write file handles are returned.
		2005
		2006	On error, nothing will be returned. If the pipe2 syscall is missing
		2007	and $flags is non-zero, fails with "ENOSYS".
		2008
		2009	Please refer to pipe2(2) for more info on the $flags, but at the
		2010	time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"
		2011	and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
		2012	supported.
		2013
		2014	Example: create a pipe race-free w.r.t. threads and fork:
		2015
		2016	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2017	or die "pipe2: $!\n";
		2018
		2019	$fh = IO::AIO::memfd_create $pathname[, $flags]
		2020	This is a direct interface to the Linux memfd_create(2) system call.
		2021	The (unhelpful) default for $flags is 0, but your default should be
		2022	"IO::AIO::MFD_CLOEXEC".
		2023
		2024	On success, the new memfd filehandle is returned, otherwise returns
		2025	"undef". If the memfd_create syscall is missing, fails with
		2026	"ENOSYS".
		2027
		2028	Please refer to memfd_create(2) for more info on this call.
		2029
		2030	The following $flags values are available: "IO::AIO::MFD_CLOEXEC",
		2031	"IO::AIO::MFD_ALLOW_SEALING", "IO::AIO::MFD_HUGETLB",
		2032	"IO::AIO::MFD_HUGETLB_2MB" and "IO::AIO::MFD_HUGETLB_1GB".
		2033
		2034	Example: create a new memfd.
		2035
		2036	my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
		2037	or die "memfd_create: $!\n";
		2038
		2039	$fh = IO::AIO::pidfd_open $pid[, $flags]
		2040	This is an interface to the Linux pidfd_open(2) system call. The
		2041	default for $flags is 0.
		2042
		2043	On success, a new pidfd filehandle is returned (that is already set
		2044	to close-on-exec), otherwise returns "undef". If the syscall is
		2045	missing, fails with "ENOSYS".
		2046
		2047	Example: open pid 6341 as pidfd.
		2048
		2049	my $fh = IO::AIO::pidfd_open 6341
		2050	or die "pidfd_open: $!\n";
		2051
		2052	$status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[,
		2053	$flags]]
		2054	This is an interface to the Linux pidfd_send_signal system call. The
		2055	default for $siginfo is "undef" and the default for $flags is 0.
		2056
		2057	Returns the system call status. If the syscall is missing, fails
		2058	with "ENOSYS".
		2059
		2060	When specified, $siginfo must be a reference to a hash with one or
		2061	more of the following members:
		2062
		2063	code - the "si_code" member
		2064	pid - the "si_pid" member
		2065	uid - the "si_uid" member
		2066	value_int - the "si_value.sival_int" member
		2067	value_ptr - the "si_value.sival_ptr" member, specified as an integer
		2068
		2069	Example: send a SIGKILL to the specified process.
		2070
		2071	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
		2072	and die "pidfd_send_signal: $!\n";
		2073
		2074	Example: send a SIGKILL to the specified process with extra data.
		2075
		2076	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
		2077	and die "pidfd_send_signal: $!\n";
		2078
		2079	$fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
		2080	This is an interface to the Linux pidfd_getfd system call. The
		2081	default for $flags is 0.
		2082
		2083	On success, returns a dup'ed copy of the target file descriptor
		2084	(specified as an integer) returned (that is already set to
		2085	close-on-exec), otherwise returns "undef". If the syscall is
		2086	missing, fails with "ENOSYS".
		2087
		2088	Example: get a copy of standard error of another process and print
		2089	soemthing to it.
		2090
		2091	my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
		2092	or die "pidfd_getfd: $!\n";
		2093	print $errfh "stderr\n";
		2094
		2095	$fh = IO::AIO::eventfd [$initval, [$flags]]
		2096	This is a direct interface to the Linux eventfd(2) system call. The
		2097	(unhelpful) defaults for $initval and $flags are 0 for both.
		2098
		2099	On success, the new eventfd filehandle is returned, otherwise
		2100	returns "undef". If the eventfd syscall is missing, fails with
		2101	"ENOSYS".
		2102
		2103	Please refer to eventfd(2) for more info on this call.
		2104
		2105	The following symbol flag values are available:
		2106	"IO::AIO::EFD_CLOEXEC", "IO::AIO::EFD_NONBLOCK" and
		2107	"IO::AIO::EFD_SEMAPHORE" (Linux 2.6.30).
		2108
		2109	Example: create a new eventfd filehandle:
		2110
		2111	$fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
		2112	or die "eventfd: $!\n";
		2113
		2114	$fh = IO::AIO::timerfd_create $clockid[, $flags]
		2115	This is a direct interface to the Linux timerfd_create(2) system
		2116	call. The (unhelpful) default for $flags is 0, but your default
		2117	should be "IO::AIO::TFD_CLOEXEC".
		2118
		2119	On success, the new timerfd filehandle is returned, otherwise
		2120	returns "undef". If the timerfd_create syscall is missing, fails
		2121	with "ENOSYS".
		2122
		2123	Please refer to timerfd_create(2) for more info on this call.
		2124
		2125	The following $clockid values are available:
		2126	"IO::AIO::CLOCK_REALTIME", "IO::AIO::CLOCK_MONOTONIC"
		2127	"IO::AIO::CLOCK_CLOCK_BOOTTIME" (Linux 3.15)
		2128	"IO::AIO::CLOCK_CLOCK_REALTIME_ALARM" (Linux 3.11) and
		2129	"IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM" (Linux 3.11).
		2130
		2131	The following $flags values are available (Linux 2.6.27):
		2132	"IO::AIO::TFD_NONBLOCK" and "IO::AIO::TFD_CLOEXEC".
		2133
		2134	Example: create a new timerfd and set it to one-second repeated
		2135	alarms, then wait for two alarms:
		2136
		2137	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2138	or die "timerfd_create: $!\n";
		2139
		2140	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2141	or die "timerfd_settime: $!\n";
		2142
		2143	for (1..2) {
		2144	8 == sysread $fh, my $buf, 8
		2145	or die "timerfd read failure\n";
		2146
		2147	printf "number of expirations (likely 1): %d\n",
		2148	unpack "Q", $buf;
		2149	}
		2150
		2151	($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags,
		2152	$new_interval, $nbw_value
		2153	This is a direct interface to the Linux timerfd_settime(2) system
		2154	call. Please refer to its manpage for more info on this call.
		2155
		2156	The new itimerspec is specified using two (possibly fractional)
		2157	second values, $new_interval and $new_value).
		2158
		2159	On success, the current interval and value are returned (as per
		2160	"timerfd_gettime"). On failure, the empty list is returned.
		2161
		2162	The following $flags values are available:
		2163	"IO::AIO::TFD_TIMER_ABSTIME" and "IO::AIO::TFD_TIMER_CANCEL_ON_SET".
		2164
		2165	See "IO::AIO::timerfd_create" for a full example.
		2166
		2167	($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2168	This is a direct interface to the Linux timerfd_gettime(2) system
		2169	call. Please refer to its manpage for more info on this call.
		2170
		2171	On success, returns the current values of interval and value for the
		2172	given timerfd (as potentially fractional second values). On failure,
		2173	the empty list is returned.
1666		2174
1667	EVENT LOOP INTEGRATION	2175	EVENT LOOP INTEGRATION
1668	It is recommended to use AnyEvent::AIO to integrate IO::AIO	2176	It is recommended to use AnyEvent::AIO to integrate IO::AIO
1669	automatically into many event loops:	2177	automatically into many event loops:
1670		2178
…		…
1720	forking, if "IO::AIO" was used in the parent. Calling it while	2228	forking, if "IO::AIO" was used in the parent. Calling it while
1721	IO::AIO is active in the process will result in undefined behaviour.	2229	IO::AIO is active in the process will result in undefined behaviour.
1722	Calling it at any time will also result in any undefined (by POSIX)	2230	Calling it at any time will also result in any undefined (by POSIX)
1723	behaviour.	2231	behaviour.
1724		2232
		2233	LINUX-SPECIFIC CALLS
		2234	When a call is documented as "linux-specific" then this means it
		2235	originated on GNU/Linux. "IO::AIO" will usually try to autodetect the
		2236	availability and compatibility of such calls regardless of the platform
		2237	it is compiled on, so platforms such as FreeBSD which often implement
		2238	these calls will work. When in doubt, call them and see if they fail wth
		2239	"ENOSYS".
		2240
1725	MEMORY USAGE	2241	MEMORY USAGE
1726	Per-request usage:	2242	Per-request usage:
1727		2243
1728	Each aio request uses - depending on your architecture - around 100-200	2244	Each aio request uses - depending on your architecture - around 100-200
1729	bytes of memory. In addition, stat requests need a stat buffer (possibly	2245	bytes of memory. In addition, stat requests need a stat buffer (possibly
…		…
1739	In the execution phase, some aio requests require more memory for	2255	In the execution phase, some aio requests require more memory for
1740	temporary buffers, and each thread requires a stack and other data	2256	temporary buffers, and each thread requires a stack and other data
1741	structures (usually around 16k-128k, depending on the OS).	2257	structures (usually around 16k-128k, depending on the OS).
1742		2258
1743	KNOWN BUGS	2259	KNOWN BUGS
1744	Known bugs will be fixed in the next release.	2260	Known bugs will be fixed in the next release :)
		2261
		2262	KNOWN ISSUES
		2263	Calls that try to "import" foreign memory areas (such as "IO::AIO::mmap"
		2264	or "IO::AIO::aio_slurp") do not work with generic lvalues, such as
		2265	non-created hash slots or other scalars I didn't think of. It's best to
		2266	avoid such and either use scalar variables or making sure that the
		2267	scalar exists (e.g. by storing "undef") and isn't "funny" (e.g. tied).
		2268
		2269	I am not sure anything can be done about this, so this is considered a
		2270	known issue, rather than a bug.
1745		2271
1746	SEE ALSO	2272	SEE ALSO
1747	AnyEvent::AIO for easy integration into event loops, Coro::AIO for a	2273	AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
1748	more natural syntax.	2274	more natural syntax and IO::FDPass for file descriptor passing.
1749		2275
1750	AUTHOR	2276	AUTHOR
1751	Marc Lehmann <schmorp@schmorp.de>	2277	Marc Lehmann <schmorp@schmorp.de>
1752	http://home.schmorp.de/	2278	http://home.schmorp.de/
1753		2279

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Revision 1.53 by root, Thu Oct 11 03:20:52 2012 UTC vs.
Revision 1.69 by root, Tue Sep 6 10:56:12 2022 UTC