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

Comparing IO-AIO/README (file contents):
Revision 1.57 by root, Mon Jan 18 11:53:09 2016 UTC vs.
Revision 1.70 by root, Sat Apr 1 02:14:05 2023 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 {
54	functions available on many operating systems. However, they are often	54	functions available on many operating systems. However, they are often
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
		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.
59		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.
…		…
173	aio_link $srcpath, $dstpath, $callback->($status)	177	aio_link $srcpath, $dstpath, $callback->($status)
174	aio_symlink $srcpath, $dstpath, $callback->($status)	178	aio_symlink $srcpath, $dstpath, $callback->($status)
175	aio_readlink $pathname, $callback->($link)	179	aio_readlink $pathname, $callback->($link)
176	aio_realpath $pathname, $callback->($path)	180	aio_realpath $pathname, $callback->($path)
177	aio_rename $srcpath, $dstpath, $callback->($status)	181	aio_rename $srcpath, $dstpath, $callback->($status)
		182	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
178	aio_mkdir $pathname, $mode, $callback->($status)	183	aio_mkdir $pathname, $mode, $callback->($status)
179	aio_rmdir $pathname, $callback->($status)	184	aio_rmdir $pathname, $callback->($status)
180	aio_readdir $pathname, $callback->($entries)	185	aio_readdir $pathname, $callback->($entries)
181	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	186	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
182	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	187	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
…		…
184	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	189	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
185	aio_load $pathname, $data, $callback->($status)	190	aio_load $pathname, $data, $callback->($status)
186	aio_copy $srcpath, $dstpath, $callback->($status)	191	aio_copy $srcpath, $dstpath, $callback->($status)
187	aio_move $srcpath, $dstpath, $callback->($status)	192	aio_move $srcpath, $dstpath, $callback->($status)
188	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)
189	aio_sync $callback->($status)	196	aio_sync $callback->($status)
190	aio_syncfs $fh, $callback->($status)	197	aio_syncfs $fh, $callback->($status)
191	aio_fsync $fh, $callback->($status)	198	aio_fsync $fh, $callback->($status)
192	aio_fdatasync $fh, $callback->($status)	199	aio_fdatasync $fh, $callback->($status)
193	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	200	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
194	aio_pathsync $pathname, $callback->($status)	201	aio_pathsync $pathname, $callback->($status)
195	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	202	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
196	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	203	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
197	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	204	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
198	aio_mlockall $flags, $callback->($status)	205	aio_mlockall $flags, $callback->($status)
199	aio_group $callback->(...)	206	aio_group $callback->(...)
200	aio_nop $callback->()	207	aio_nop $callback->()
…		…
214	IO::AIO::idle_timeout $seconds	221	IO::AIO::idle_timeout $seconds
215	IO::AIO::max_outstanding $maxreqs	222	IO::AIO::max_outstanding $maxreqs
216	IO::AIO::nreqs	223	IO::AIO::nreqs
217	IO::AIO::nready	224	IO::AIO::nready
218	IO::AIO::npending	225	IO::AIO::npending
		226	IO::AIO::reinit
		227
		228	$nfd = IO::AIO::get_fdlimit
		229	IO::AIO::min_fdlimit $nfd
219		230
220	IO::AIO::sendfile $ofh, $ifh, $offset, $count	231	IO::AIO::sendfile $ofh, $ifh, $offset, $count
221	IO::AIO::fadvise $fh, $offset, $len, $advice	232	IO::AIO::fadvise $fh, $offset, $len, $advice
		233	IO::AIO::fexecve $fh, $argv, $envp
		234
222	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]	235	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
223	IO::AIO::munmap $scalar	236	IO::AIO::munmap $scalar
		237	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
224	IO::AIO::madvise $scalar, $offset, $length, $advice	238	IO::AIO::madvise $scalar, $offset, $length, $advice
225	IO::AIO::mprotect $scalar, $offset, $length, $protect	239	IO::AIO::mprotect $scalar, $offset, $length, $protect
226	IO::AIO::munlock $scalar, $offset = 0, $length = undef	240	IO::AIO::munlock $scalar, $offset = 0, $length = undef
227	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
228		272
229	API NOTES	273	API NOTES
230	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
231	with the same name (sans "aio_"). The arguments are similar or	275	with the same name (sans "aio_"). The arguments are similar or
232	identical, and they all accept an additional (and optional) $callback	276	identical, and they all accept an additional (and optional) $callback
…		…
299	aio_open $pathname, $flags, $mode, $callback->($fh)	343	aio_open $pathname, $flags, $mode, $callback->($fh)
300	Asynchronously open or create a file and call the callback with a	344	Asynchronously open or create a file and call the callback with a
301	newly created filehandle for the file (or "undef" in case of an	345	newly created filehandle for the file (or "undef" in case of an
302	error).	346	error).
303		347
304	The pathname passed to "aio_open" must be absolute. See API NOTES,
305	above, for an explanation.
306
307	The $flags argument is a bitmask. See the "Fcntl" module for a list.	348	The $flags argument is a bitmask. See the "Fcntl" module for a list.
308	They are the same as used by "sysopen".	349	They are the same as used by "sysopen".
309		350
310	Likewise, $mode specifies the mode of the newly created file, if it	351	Likewise, $mode specifies the mode of the newly created file, if it
311	didn't exist and "O_CREAT" has been given, just like perl's	352	didn't exist and "O_CREAT" has been given, just like perl's
…		…
330	"O_APPEND"), the following POSIX and non-POSIX constants are	371	"O_APPEND"), the following POSIX and non-POSIX constants are
331	available (missing ones on your system are, as usual, 0):	372	available (missing ones on your system are, as usual, 0):
332		373
333	"O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",	374	"O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
334	"O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",	375	"O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
335	"O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", and	376	"O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", "O_TTY_INIT"
336	"O_TTY_INIT".	377	and "O_ACCMODE".
337		378
338	aio_close $fh, $callback->($status)	379	aio_close $fh, $callback->($status)
339	Asynchronously close a file and call the callback with the result	380	Asynchronously close a file and call the callback with the result
340	code.	381	code.
341		382
…		…
371		412
372	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	413	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
373	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	414	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
374	Reads or writes $length bytes from or to the specified $fh and	415	Reads or writes $length bytes from or to the specified $fh and
375	$offset into the scalar given by $data and offset $dataoffset and	416	$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	417	calls the callback with the actual number of bytes transferred (or
377	error, just like the syscall).	418	-1 on error, just like the syscall).
378		419
379	"aio_read" will, like "sysread", shrink or grow the $data scalar to	420	"aio_read" will, like "sysread", shrink or grow the $data scalar to
380	offset plus the actual number of bytes read.	421	offset plus the actual number of bytes read.
381		422
382	If $offset is undefined, then the current file descriptor offset	423	If $offset is undefined, then the current file descriptor offset
…		…
439	As native sendfile syscalls (as practically any non-POSIX interface	480	As native sendfile syscalls (as practically any non-POSIX interface
440	hacked together in a hurry to improve benchmark numbers) tend to be	481	hacked together in a hurry to improve benchmark numbers) tend to be
441	rather buggy on many systems, this implementation tries to work	482	rather buggy on many systems, this implementation tries to work
442	around some known bugs in Linux and FreeBSD kernels (probably	483	around some known bugs in Linux and FreeBSD kernels (probably
443	others, too), but that might fail, so you really really should check	484	others, too), but that might fail, so you really really should check
444	the return value of "aio_sendfile" - fewre bytes than expected might	485	the return value of "aio_sendfile" - fewer bytes than expected might
445	have been transferred.	486	have been transferred.
446		487
447	aio_readahead $fh,$offset,$length, $callback->($retval)	488	aio_readahead $fh,$offset,$length, $callback->($retval)
448	"aio_readahead" populates the page cache with data from a file so	489	"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	490	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	494	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	495	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	496	read beyond the end of the file. The current file offset of the file
456	is left unchanged.	497	is left unchanged.
457		498
458	If that syscall doesn't exist (likely if your OS isn't Linux) it	499	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	500	will be emulated by simply reading the data, which would have a
460	similar effect.	501	similar effect.
461		502
462	aio_stat $fh_or_path, $callback->($status)	503	aio_stat $fh_or_path, $callback->($status)
463	aio_lstat $fh, $callback->($status)	504	aio_lstat $fh, $callback->($status)
464	Works like perl's "stat" or "lstat" in void context. The callback	505	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	506	The callback will be called after the stat and the results will be
466	using "stat _" or "-s _" etc...	507	available using "stat _" or "-s _" and other tests (with the
467		508	exception of "-B" and "-T").
468	The pathname passed to "aio_stat" must be absolute. See API NOTES,
469	above, for an explanation.
470		509
471	Currently, the stats are always 64-bit-stats, i.e. instead of	510	Currently, the stats are always 64-bit-stats, i.e. instead of
472	returning an error when stat'ing a large file, the results will be	511	returning an error when stat'ing a large file, the results will be
473	silently truncated unless perl itself is compiled with large file	512	silently truncated unless perl itself is compiled with large file
474	support.	513	support.
…		…
479	back on traditional behaviour).	518	back on traditional behaviour).
480		519
481	"S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",	520	"S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
482	"S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",	521	"S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
483	"IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".	522	"IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
		523
		524	To access higher resolution stat timestamps, see "SUBSECOND STAT
		525	TIME ACCESS".
484		526
485	Example: Print the length of /etc/passwd:	527	Example: Print the length of /etc/passwd:
486		528
487	aio_stat "/etc/passwd", sub {	529	aio_stat "/etc/passwd", sub {
488	$_[0] and die "stat failed: $!";	530	$_[0] and die "stat failed: $!";
…		…
530	namemax => 255,	572	namemax => 255,
531	frsize => 1024,	573	frsize => 1024,
532	fsid => 1810	574	fsid => 1810
533	}	575	}
534		576
535	Here is a (likely partial - send me updates!) list of fsid values
536	used by Linux - it is safe to hardcode these when $^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/ext4
560	0x0000ef51 ext2
561	0xf2f52010 f2fs
562	0x00004006 fat
563	0x65735546 fuseblk
564	0x65735543 fusectl
565	0x0bad1dea futexfs
566	0x01161970 gfs2
567	0x47504653 gpfs
568	0x00004244 hfs
569	0xf995e849 hpfs
570	0x00c0ffee hostfs
571	0x958458f6 hugetlbfs
572	0x2bad1dea inotifyfs
573	0x00009660 isofs
574	0x000072b6 jffs2
575	0x3153464a jfs
576	0x6b414653 k-afs
577	0x0bd00bd0 lustre
578	0x0000137f minix
579	0x0000138f minix 30 char names
580	0x00002468 minix v2
581	0x00002478 minix v2 30 char names
582	0x00004d5a minix v3
583	0x19800202 mqueue
584	0x00004d44 msdos
585	0x0000564c novell
586	0x00006969 nfs
587	0x6e667364 nfsd
588	0x00003434 nilfs
589	0x5346544e ntfs
590	0x00009fa1 openprom
591	0x7461636F ocfs2
592	0x00009fa0 proc
593	0x6165676c pstorefs
594	0x0000002f qnx4
595	0x68191122 qnx6
596	0x858458f6 ramfs
597	0x52654973 reiserfs
598	0x00007275 romfs
599	0x67596969 rpc_pipefs
600	0x73636673 securityfs
601	0xf97cff8c selinux
602	0x0000517b smb
603	0x534f434b sockfs
604	0x73717368 squashfs
605	0x62656572 sysfs
606	0x012ff7b6 sysv2
607	0x012ff7b5 sysv4
608	0x01021994 tmpfs
609	0x15013346 udf
610	0x00011954 ufs
611	0x54190100 ufs byteswapped
612	0x00009fa2 usbdevfs
613	0x01021997 v9fs
614	0xa501fcf5 vxfs
615	0xabba1974 xenfs
616	0x012ff7b4 xenix
617	0x58465342 xfs
618	0x012fd16d xia
619
620	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	577	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
621	Works like perl's "utime" function (including the special case of	578	Works like perl's "utime" function (including the special case of
622	$atime and $mtime being undef). Fractional times are supported if	579	$atime and $mtime being undef). Fractional times are supported if
623	the underlying syscalls support them.	580	the underlying syscalls support them.
624		581
625	When called with a pathname, uses utimes(2) if available, otherwise	582	When called with a pathname, uses utimensat(2) or utimes(2) if
626	utime(2). If called on a file descriptor, uses futimes(2) if	583	available, otherwise utime(2). If called on a file descriptor, uses
627	available, otherwise returns ENOSYS, so this is not portable.	584	futimens(2) or futimes(2) if available, otherwise returns ENOSYS, so
		585	this is not portable.
628		586
629	Examples:	587	Examples:
630		588
631	# set atime and mtime to current time (basically touch(1)):	589	# set atime and mtime to current time (basically touch(1)):
632	aio_utime "path", undef, undef;	590	aio_utime "path", undef, undef;
…		…
655	$mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate	613	$mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
656	space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE \|	614	space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE \|
657	IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.	615	IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
658		616
659	IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range	617	IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range
660	(without leaving a hole) and "FALLOC_FL_ZERO_RANGE", to zero a range	618	(without leaving a hole), "FALLOC_FL_ZERO_RANGE", to zero a range,
		619	"FALLOC_FL_INSERT_RANGE" to insert a range and
		620	"FALLOC_FL_UNSHARE_RANGE" to unshare shared blocks (see your
661	(see your fallocate(2) manpage).	621	fallocate(2) manpage).
662		622
663	The file system block size used by "fallocate" is presumably the	623	The file system block size used by "fallocate" is presumably the
664	"f_bsize" returned by "statvfs".	624	"f_bsize" returned by "statvfs", but different filesystems and
		625	filetypes can dictate other limitations.
665		626
666	If "fallocate" isn't available or cannot be emulated (currently no	627	If "fallocate" isn't available or cannot be emulated (currently no
667	emulation will be attempted), passes -1 and sets $! to "ENOSYS".	628	emulation will be attempted), passes -1 and sets $! to "ENOSYS".
668		629
669	aio_chmod $fh_or_path, $mode, $callback->($status)	630	aio_chmod $fh_or_path, $mode, $callback->($status)
…		…
713		674
714	On systems that support the AIO::WD working directory abstraction	675	On systems that support the AIO::WD working directory abstraction
715	natively, the case "[$wd, "."]" as $srcpath is specialcased -	676	natively, the case "[$wd, "."]" as $srcpath is specialcased -
716	instead of failing, "rename" is called on the absolute path of $wd.	677	instead of failing, "rename" is called on the absolute path of $wd.
717		678
		679	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		680	Basically a version of "aio_rename" with an additional $flags
		681	argument. Calling this with "$flags=0" is the same as calling
		682	"aio_rename".
		683
		684	Non-zero flags are currently only supported on GNU/Linux systems
		685	that support renameat2. Other systems fail with "ENOSYS" in this
		686	case.
		687
		688	The following constants are available (missing ones are, as usual
		689	0), see renameat2(2) for details:
		690
		691	"IO::AIO::RENAME_NOREPLACE", "IO::AIO::RENAME_EXCHANGE" and
		692	"IO::AIO::RENAME_WHITEOUT".
		693
718	aio_mkdir $pathname, $mode, $callback->($status)	694	aio_mkdir $pathname, $mode, $callback->($status)
719	Asynchronously mkdir (create) a directory and call the callback with	695	Asynchronously mkdir (create) a directory and call the callback with
720	the result code. $mode will be modified by the umask at the time the	696	the result code. $mode will be modified by the umask at the time the
721	request is executed, so do not change your umask.	697	request is executed, so do not change your umask.
722		698
…		…
744	The flags are a combination of the following constants, ORed	720	The flags are a combination of the following constants, ORed
745	together (the flags will also be passed to the callback, possibly	721	together (the flags will also be passed to the callback, possibly
746	modified):	722	modified):
747		723
748	IO::AIO::READDIR_DENTS	724	IO::AIO::READDIR_DENTS
749	When this flag is off, then the callback gets an arrayref	725	Normally the callback gets an arrayref consisting of names only
750	consisting of names only (as with "aio_readdir"), otherwise it	726	(as with "aio_readdir"). If this flag is set, then the callback
751	gets an arrayref with "[$name, $type, $inode]" arrayrefs, each	727	gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
752	describing a single directory entry in more detail.	728	describing a single directory entry in more detail:
753		729
754	$name is the name of the entry.	730	$name is the name of the entry.
755		731
756	$type is one of the "IO::AIO::DT_xxx" constants:	732	$type is one of the "IO::AIO::DT_xxx" constants:
757		733
758	"IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",	734	"IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",
759	"IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",	735	"IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",
760	"IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".	736	"IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
761		737
762	"IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If	738	"IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If
763	you need to know, you have to run stat yourself. Also, for speed	739	you need to know, you have to run stat yourself. Also, for
764	reasons, the $type scalars are read-only: you can not modify	740	speed/memory reasons, the $type scalars are read-only: you must
765	them.	741	not modify them.
766		742
767	$inode is the inode number (which might not be exact on systems	743	$inode is the inode number (which might not be exact on systems
768	with 64 bit inode numbers and 32 bit perls). This field has	744	with 64 bit inode numbers and 32 bit perls). This field has
769	unspecified content on systems that do not deliver the inode	745	unspecified content on systems that do not deliver the inode
770	information.	746	information.
…		…
782	of which names with short names are tried first.	758	of which names with short names are tried first.
783		759
784	IO::AIO::READDIR_STAT_ORDER	760	IO::AIO::READDIR_STAT_ORDER
785	When this flag is set, then the names will be returned in an	761	When this flag is set, then the names will be returned in an
786	order suitable for stat()'ing each one. That is, when you plan	762	order suitable for stat()'ing each one. That is, when you plan
787	to stat() all files in the given directory, then the returned	763	to stat() most or all files in the given directory, then the
788	order will likely be fastest.	764	returned order will likely be faster.
789		765
790	If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are	766	If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
791	specified, then the likely dirs come first, resulting in a less	767	specified, then the likely dirs come first, resulting in a less
792	optimal stat order.	768	optimal stat order for stat'ing all entries, but likely a more
		769	optimal order for finding subdirectories.
793		770
794	IO::AIO::READDIR_FOUND_UNKNOWN	771	IO::AIO::READDIR_FOUND_UNKNOWN
795	This flag should not be set when calling "aio_readdirx".	772	This flag should not be set when calling "aio_readdirx".
796	Instead, it is being set by "aio_readdirx", when any of the	773	Instead, it is being set by "aio_readdirx", when any of the
797	$type's found were "IO::AIO::DT_UNKNOWN". The absence of this	774	$type's found were "IO::AIO::DT_UNKNOWN". The absence of this
798	flag therefore indicates that all $type's are known, which can	775	flag therefore indicates that all $type's are known, which can
799	be used to speed up some algorithms.	776	be used to speed up some algorithms.
800		777
		778	aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		779	Opens, reads and closes the given file. The data is put into $data,
		780	which is resized as required.
		781
		782	If $offset is negative, then it is counted from the end of the file.
		783
		784	If $length is zero, then the remaining length of the file is used.
		785	Also, in this case, the same limitations to modifying $data apply as
		786	when IO::AIO::mmap is used, i.e. it must only be modified in-place
		787	with "substr". If the size of the file is known, specifying a
		788	non-zero $length results in a performance advantage.
		789
		790	This request is similar to the older "aio_load" request, but since
		791	it is a single request, it might be more efficient to use.
		792
		793	Example: load /etc/passwd into $passwd.
		794
		795	my $passwd;
		796	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		797	$_[0] >= 0
		798	or die "/etc/passwd: $!\n";
		799
		800	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		801	print $passwd;
		802	};
		803	IO::AIO::flush;
		804
801	aio_load $pathname, $data, $callback->($status)	805	aio_load $pathname, $data, $callback->($status)
802	This is a composite request that tries to fully load the given file	806	This is a composite request that tries to fully load the given file
803	into memory. Status is the same as with aio_read.	807	into memory. Status is the same as with aio_read.
		808
		809	Using "aio_slurp" might be more efficient, as it is a single
		810	request.
804		811
805	aio_copy $srcpath, $dstpath, $callback->($status)	812	aio_copy $srcpath, $dstpath, $callback->($status)
806	Try to copy the file (directories not supported as either source	813	Try to copy the file (directories not supported as either source
807	or destination) from $srcpath to $dstpath and call the callback with	814	or destination) from $srcpath to $dstpath and call the callback with
808	a status of 0 (ok) or -1 (error, see $!).	815	a status of 0 (ok) or -1 (error, see $!).
		816
		817	Existing destination files will be truncated.
809		818
810	This is a composite request that creates the destination file with	819	This is a composite request that creates the destination file with
811	mode 0200 and copies the contents of the source file into it using	820	mode 0200 and copies the contents of the source file into it using
812	"aio_sendfile", followed by restoring atime, mtime, access mode and	821	"aio_sendfile", followed by restoring atime, mtime, access mode and
813	uid/gid, in that order.	822	uid/gid, in that order.
…		…
830	to efficiently separate the entries of directory $path into two sets	839	to efficiently separate the entries of directory $path into two sets
831	of names, directories you can recurse into (directories), and ones	840	of names, directories you can recurse into (directories), and ones
832	you cannot recurse into (everything else, including symlinks to	841	you cannot recurse into (everything else, including symlinks to
833	directories).	842	directories).
834		843
835	"aio_scandir" is a composite request that creates of many sub	844	"aio_scandir" is a composite request that generates many sub
836	requests_ $maxreq specifies the maximum number of outstanding aio	845	requests. $maxreq specifies the maximum number of outstanding aio
837	requests that this function generates. If it is "<= 0", then a	846	requests that this function generates. If it is "<= 0", then a
838	suitable default will be chosen (currently 4).	847	suitable default will be chosen (currently 4).
839		848
840	On error, the callback is called without arguments, otherwise it	849	On error, the callback is called without arguments, otherwise it
841	receives two array-refs with path-relative entry names.	850	receives two array-refs with path-relative entry names.
…		…
888	Delete a directory tree starting (and including) $path, return the	897	Delete a directory tree starting (and including) $path, return the
889	status of the final "rmdir" only. This is a composite request that	898	status of the final "rmdir" only. This is a composite request that
890	uses "aio_scandir" to recurse into and rmdir directories, and unlink	899	uses "aio_scandir" to recurse into and rmdir directories, and unlink
891	everything else.	900	everything else.
892		901
		902	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		903	aio_ioctl $fh, $request, $buf, $callback->($status)
		904	These work just like the "fcntl" and "ioctl" built-in functions,
		905	except they execute asynchronously and pass the return value to the
		906	callback.
		907
		908	Both calls can be used for a lot of things, some of which make more
		909	sense to run asynchronously in their own thread, while some others
		910	make less sense. For example, calls that block waiting for external
		911	events, such as locking, will also lock down an I/O thread while it
		912	is waiting, which can deadlock the whole I/O system. At the same
		913	time, there might be no alternative to using a thread to wait.
		914
		915	So in general, you should only use these calls for things that do
		916	(filesystem) I/O, not for things that wait for other events
		917	(network, other processes), although if you are careful and know
		918	what you are doing, you still can.
		919
		920	The following constants are available and can be used for normal
		921	"ioctl" and "fcntl" as well (missing ones are, as usual 0):
		922
		923	"F_DUPFD_CLOEXEC",
		924
		925	"F_OFD_GETLK", "F_OFD_SETLK", "F_OFD_GETLKW",
		926
		927	"FIFREEZE", "FITHAW", "FITRIM", "FICLONE", "FICLONERANGE",
		928	"FIDEDUPERANGE".
		929
		930	"F_ADD_SEALS", "F_GET_SEALS", "F_SEAL_SEAL", "F_SEAL_SHRINK",
		931	"F_SEAL_GROW" and "F_SEAL_WRITE".
		932
		933	"FS_IOC_GETFLAGS", "FS_IOC_SETFLAGS", "FS_IOC_GETVERSION",
		934	"FS_IOC_SETVERSION", "FS_IOC_FIEMAP".
		935
		936	"FS_IOC_FSGETXATTR", "FS_IOC_FSSETXATTR",
		937	"FS_IOC_SET_ENCRYPTION_POLICY", "FS_IOC_GET_ENCRYPTION_PWSALT",
		938	"FS_IOC_GET_ENCRYPTION_POLICY", "FS_KEY_DESCRIPTOR_SIZE".
		939
		940	"FS_SECRM_FL", "FS_UNRM_FL", "FS_COMPR_FL", "FS_SYNC_FL",
		941	"FS_IMMUTABLE_FL", "FS_APPEND_FL", "FS_NODUMP_FL", "FS_NOATIME_FL",
		942	"FS_DIRTY_FL", "FS_COMPRBLK_FL", "FS_NOCOMP_FL", "FS_ENCRYPT_FL",
		943	"FS_BTREE_FL", "FS_INDEX_FL", "FS_JOURNAL_DATA_FL", "FS_NOTAIL_FL",
		944	"FS_DIRSYNC_FL", "FS_TOPDIR_FL", "FS_FL_USER_MODIFIABLE".
		945
		946	"FS_XFLAG_REALTIME", "FS_XFLAG_PREALLOC", "FS_XFLAG_IMMUTABLE",
		947	"FS_XFLAG_APPEND", "FS_XFLAG_SYNC", "FS_XFLAG_NOATIME",
		948	"FS_XFLAG_NODUMP", "FS_XFLAG_RTINHERIT", "FS_XFLAG_PROJINHERIT",
		949	"FS_XFLAG_NOSYMLINKS", "FS_XFLAG_EXTSIZE", "FS_XFLAG_EXTSZINHERIT",
		950	"FS_XFLAG_NODEFRAG", "FS_XFLAG_FILESTREAM", "FS_XFLAG_DAX",
		951	"FS_XFLAG_HASATTR",
		952
		953	"BLKROSET", "BLKROGET", "BLKRRPART", "BLKGETSIZE", "BLKFLSBUF",
		954	"BLKRASET", "BLKRAGET", "BLKFRASET", "BLKFRAGET", "BLKSECTSET",
		955	"BLKSECTGET", "BLKSSZGET", "BLKBSZGET", "BLKBSZSET", "BLKGETSIZE64",
		956
893	aio_sync $callback->($status)	957	aio_sync $callback->($status)
894	Asynchronously call sync and call the callback when finished.	958	Asynchronously call sync and call the callback when finished.
895		959
896	aio_fsync $fh, $callback->($status)	960	aio_fsync $fh, $callback->($status)
897	Asynchronously call fsync on the given filehandle and call the	961	Asynchronously call fsync on the given filehandle and call the
…		…
933	Future versions of this function might fall back to other methods	997	Future versions of this function might fall back to other methods
934	when "fsync" on the directory fails (such as calling "sync").	998	when "fsync" on the directory fails (such as calling "sync").
935		999
936	Passes 0 when everything went ok, and -1 on error.	1000	Passes 0 when everything went ok, and -1 on error.
937		1001
938	aio_msync $scalar, $offset = 0, $length = undef, flags = 0,	1002	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC,
939	$callback->($status)	1003	$callback->($status)
940	This is a rather advanced IO::AIO call, which only works on	1004	This is a rather advanced IO::AIO call, which only works on
941	mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it	1005	mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
942	also works on data scalars managed by the Sys::Mmap or Mmap modules,	1006	also works on data scalars managed by the Sys::Mmap or Mmap modules,
943	note that the scalar must only be modified in-place while an aio	1007	note that the scalar must only be modified in-place while an aio
…		…
945		1009
946	It calls the "msync" function of your OS, if available, with the	1010	It calls the "msync" function of your OS, if available, with the
947	memory area starting at $offset in the string and ending $length	1011	memory area starting at $offset in the string and ending $length
948	bytes later. If $length is negative, counts from the end, and if	1012	bytes later. If $length is negative, counts from the end, and if
949	$length is "undef", then it goes till the end of the string. The	1013	$length is "undef", then it goes till the end of the string. The
950	flags can be a combination of "IO::AIO::MS_ASYNC",	1014	flags can be either "IO::AIO::MS_ASYNC" or "IO::AIO::MS_SYNC", plus
951	"IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC".	1015	an optional "IO::AIO::MS_INVALIDATE".
952		1016
953	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,	1017	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
954	$callback->($status)	1018	$callback->($status)
955	This is a rather advanced IO::AIO call, which works best on	1019	This is a rather advanced IO::AIO call, which works best on
956	mmap(2)ed scalars.	1020	mmap(2)ed scalars.
…		…
987	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;	1051	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
988	aio_mlock $data; # mlock in background	1052	aio_mlock $data; # mlock in background
989		1053
990	aio_mlockall $flags, $callback->($status)	1054	aio_mlockall $flags, $callback->($status)
991	Calls the "mlockall" function with the given $flags (a combination	1055	Calls the "mlockall" function with the given $flags (a combination
992	of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE").	1056	of "IO::AIO::MCL_CURRENT", "IO::AIO::MCL_FUTURE" and
		1057	"IO::AIO::MCL_ONFAULT").
993		1058
994	On systems that do not implement "mlockall", this function returns	1059	On systems that do not implement "mlockall", this function returns
995	-1 and sets errno to "ENOSYS".	1060	-1 and sets errno to "ENOSYS". Similarly, flag combinations not
		1061	supported by the system result in a return value of -1 with errno
		1062	being set to "EINVAL".
996		1063
997	Note that the corresponding "munlockall" is synchronous and is	1064	Note that the corresponding "munlockall" is synchronous and is
998	documented under "MISCELLANEOUS FUNCTIONS".	1065	documented under "MISCELLANEOUS FUNCTIONS".
999		1066
1000	Example: asynchronously lock all current and future pages into	1067	Example: asynchronously lock all current and future pages into
…		…
1042	"IO::AIO::FIEMAP_EXTENT_DATA_INLINE",	1109	"IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
1043	"IO::AIO::FIEMAP_EXTENT_DATA_TAIL",	1110	"IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
1044	"IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"	1111	"IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
1045	or "IO::AIO::FIEMAP_EXTENT_SHARED".	1112	or "IO::AIO::FIEMAP_EXTENT_SHARED".
1046		1113
1047	At the time of this writing (Linux 3.2), this requets is unreliable	1114	At the time of this writing (Linux 3.2), this request is unreliable
1048	unless $count is "undef", as the kernel has all sorts of bugs	1115	unless $count is "undef", as the kernel has all sorts of bugs
1049	preventing it to return all extents of a range for files with large	1116	preventing it to return all extents of a range for files with a
1050	number of extents. The code works around all these issues if $count	1117	large number of extents. The code (only) works around all these
1051	is undef.	1118	issues if $count is "undef".
1052		1119
1053	aio_group $callback->(...)	1120	aio_group $callback->(...)
1054	This is a very special aio request: Instead of doing something, it	1121	This is a very special aio request: Instead of doing something, it
1055	is a container for other aio requests, which is useful if you want	1122	is a container for other aio requests, which is useful if you want
1056	to bundle many requests into a single, composite, request with a	1123	to bundle many requests into a single, composite, request with a
…		…
1165	There are some caveats: when directories get renamed (or deleted), the	1232	There are some caveats: when directories get renamed (or deleted), the
1166	pathname string doesn't change, so will point to the new directory (or	1233	pathname string doesn't change, so will point to the new directory (or
1167	nowhere at all), while the directory fd, if available on the system,	1234	nowhere at all), while the directory fd, if available on the system,
1168	will still point to the original directory. Most functions accepting a	1235	will still point to the original directory. Most functions accepting a
1169	pathname will use the directory fd on newer systems, and the string on	1236	pathname will use the directory fd on newer systems, and the string on
1170	older systems. Some functions (such as realpath) will always rely on the	1237	older systems. Some functions (such as "aio_realpath") will always rely
1171	string form of the pathname.	1238	on the string form of the pathname.
1172		1239
1173	So this functionality is mainly useful to get some protection against	1240	So this functionality is mainly useful to get some protection against
1174	"chdir", to easily get an absolute path out of a relative path for	1241	"chdir", to easily get an absolute path out of a relative path for
1175	future reference, and to speed up doing many operations in the same	1242	future reference, and to speed up doing many operations in the same
1176	directory (e.g. when stat'ing all files in a directory).	1243	directory (e.g. when stat'ing all files in a directory).
…		…
1189	fails the request with "ENOENT", there is often no need for error	1256	fails the request with "ENOENT", there is often no need for error
1190	checking in the "aio_wd" callback, as future requests using the	1257	checking in the "aio_wd" callback, as future requests using the
1191	value will fail in the expected way.	1258	value will fail in the expected way.
1192		1259
1193	IO::AIO::CWD	1260	IO::AIO::CWD
1194	This is a compiletime constant (object) that represents the process	1261	This is a compile time constant (object) that represents the process
1195	current working directory.	1262	current working directory.
1196		1263
1197	Specifying this object as working directory object for a pathname is	1264	Specifying this object as working directory object for a pathname is
1198	as if the pathname would be specified directly, without a directory	1265	as if the pathname would be specified directly, without a directory
1199	object. For example, these calls are functionally identical:	1266	object. For example, these calls are functionally identical:
…		…
1424	Strictly equivalent to:	1491	Strictly equivalent to:
1425		1492
1426	IO::AIO::poll_wait, IO::AIO::poll_cb	1493	IO::AIO::poll_wait, IO::AIO::poll_cb
1427	while IO::AIO::nreqs;	1494	while IO::AIO::nreqs;
1428		1495
		1496	This function can be useful at program aborts, to make sure
		1497	outstanding I/O has been done ("IO::AIO" uses an "END" block which
		1498	already calls this function on normal exits), or when you are merely
		1499	using "IO::AIO" for its more advanced functions, rather than for
		1500	async I/O, e.g.:
		1501
		1502	my ($dirs, $nondirs);
		1503	IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
		1504	IO::AIO::flush;
		1505	# $dirs, $nondirs are now set
		1506
1429	IO::AIO::max_poll_reqs $nreqs	1507	IO::AIO::max_poll_reqs $nreqs
1430	IO::AIO::max_poll_time $seconds	1508	IO::AIO::max_poll_time $seconds
1431	These set the maximum number of requests (default 0, meaning	1509	These set the maximum number of requests (default 0, meaning
1432	infinity) that are being processed by "IO::AIO::poll_cb" in one	1510	infinity) that are being processed by "IO::AIO::poll_cb" in one
1433	call, respectively the maximum amount of time (default 0, meaning	1511	call, respectively the maximum amount of time (default 0, meaning
…		…
1522	no longer exceeded.	1600	no longer exceeded.
1523		1601
1524	In other words, this setting does not enforce a queue limit, but can	1602	In other words, this setting does not enforce a queue limit, but can
1525	be used to make poll functions block if the limit is exceeded.	1603	be used to make poll functions block if the limit is exceeded.
1526		1604
1527	This is a very bad function to use in interactive programs because	1605	This is a bad function to use in interactive programs because it
1528	it blocks, and a bad way to reduce concurrency because it is	1606	blocks, and a bad way to reduce concurrency because it is inexact.
1529	inexact: Better use an "aio_group" together with a feed callback.	1607	If you need to issue many requests without being able to call a poll
		1608	function on demand, it is better to use an "aio_group" together with
		1609	a feed callback.
1530		1610
1531	Its main use is in scripts without an event loop - when you want to	1611	Its main use is in scripts without an event loop - when you want to
1532	stat a lot of files, you can write somehting like this:	1612	stat a lot of files, you can write something like this:
1533		1613
1534	IO::AIO::max_outstanding 32;	1614	IO::AIO::max_outstanding 32;
1535		1615
1536	for my $path (...) {	1616	for my $path (...) {
1537	aio_stat $path , ...;	1617	aio_stat $path , ...;
…		…
1539	}	1619	}
1540		1620
1541	IO::AIO::flush;	1621	IO::AIO::flush;
1542		1622
1543	The call to "poll_cb" inside the loop will normally return	1623	The call to "poll_cb" inside the loop will normally return
1544	instantly, but as soon as more thna 32 reqeusts are in-flight, it	1624	instantly, allowing the loop to progress, but as soon as more than
1545	will block until some requests have been handled. This keeps the	1625	32 requests are in-flight, it will block until some requests have
1546	loop from pushing a large number of "aio_stat" requests onto the	1626	been handled. This keeps the loop from pushing a large number of
1547	queue.	1627	"aio_stat" requests onto the queue (which, with many paths to stat,
		1628	can use up a lot of memory).
1548		1629
1549	The default value for "max_outstanding" is very large, so there is	1630	The default value for "max_outstanding" is very large, so there is
1550	no practical limit on the number of outstanding requests.	1631	no practical limit on the number of outstanding requests.
1551		1632
1552	STATISTICAL INFORMATION	1633	STATISTICAL INFORMATION
…		…
1566		1647
1567	IO::AIO::npending	1648	IO::AIO::npending
1568	Returns the number of requests currently in the pending state	1649	Returns the number of requests currently in the pending state
1569	(executed, but not yet processed by poll_cb).	1650	(executed, but not yet processed by poll_cb).
1570		1651
		1652	SUBSECOND STAT TIME ACCESS
		1653	Both "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" functions can
		1654	generally find access/modification and change times with subsecond time
		1655	accuracy of the system supports it, but perl's built-in functions only
		1656	return the integer part.
		1657
		1658	The following functions return the timestamps of the most recent stat
		1659	with subsecond precision on most systems and work both after
		1660	"aio_stat"/"aio_lstat" and perl's "stat"/"lstat" calls. Their return
		1661	value is only meaningful after a successful "stat"/"lstat" call, or
		1662	during/after a successful "aio_stat"/"aio_lstat" callback.
		1663
		1664	This is similar to the Time::HiRes "stat" functions, but can return full
		1665	resolution without rounding and work with standard perl "stat",
		1666	alleviating the need to call the special "Time::HiRes" functions, which
		1667	do not act like their perl counterparts.
		1668
		1669	On operating systems or file systems where subsecond time resolution is
		1670	not supported or could not be detected, a fractional part of 0 is
		1671	returned, so it is always safe to call these functions.
		1672
		1673	$seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime,
		1674	IO::AIO::st_btime
		1675	Return the access, modication, change or birth time, respectively,
		1676	including fractional part. Due to the limited precision of floating
		1677	point, the accuracy on most platforms is only a bit better than
		1678	milliseconds for times around now - see the nsec function family,
		1679	below, for full accuracy.
		1680
		1681	File birth time is only available when the OS and perl support it
		1682	(on FreeBSD and NetBSD at the time of this writing, although support
		1683	is adaptive, so if your OS/perl gains support, IO::AIO can take
		1684	advantage of it). On systems where it isn't available, 0 is
		1685	currently returned, but this might change to "undef" in a future
		1686	version.
		1687
		1688	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		1689	Returns access, modification, change and birth time all in one go,
		1690	and maybe more times in the future version.
		1691
		1692	$nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec,
		1693	IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		1694	Return the fractional access, modifcation, change or birth time, in
		1695	nanoseconds, as an integer in the range 0 to 999999999.
		1696
		1697	Note that no accessors are provided for access, modification and
		1698	change times - you need to get those from "stat _" if required ("int
		1699	IO::AIO::st_atime" and so on will not generally give you the
		1700	correct value).
		1701
		1702	$seconds = IO::AIO::st_btimesec
		1703	The (integral) seconds part of the file birth time, if available.
		1704
		1705	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		1706	Like the functions above, but returns all four times in one go (and
		1707	maybe more in future versions).
		1708
		1709	$counter = IO::AIO::st_gen
		1710	Returns the generation counter (in practice this is just a random
		1711	number) of the file. This is only available on platforms which have
		1712	this member in their "struct stat" (most BSDs at the time of this
		1713	writing) and generally only to the root usert. If unsupported, 0 is
		1714	returned, but this might change to "undef" in a future version.
		1715
		1716	Example: print the high resolution modification time of /etc, using
		1717	"stat", and "IO::AIO::aio_stat".
		1718
		1719	if (stat "/etc") {
		1720	printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
		1721	}
		1722
		1723	IO::AIO::aio_stat "/etc", sub {
		1724	$_[0]
		1725	and return;
		1726
		1727	printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
		1728	};
		1729
		1730	IO::AIO::flush;
		1731
		1732	Output of the awbove on my system, showing reduced and full accuracy:
		1733
		1734	stat(/etc) mtime: 1534043702.020808
		1735	aio_stat(/etc) mtime: 1534043702.020807792
		1736
1571	MISCELLANEOUS FUNCTIONS	1737	MISCELLANEOUS FUNCTIONS
1572	IO::AIO implements some functions that are useful when you want to use	1738	IO::AIO implements some functions that are useful when you want to use
1573	some "Advanced I/O" function not available to in Perl, without going the	1739	some "Advanced I/O" function not available to in Perl, without going the
1574	"Asynchronous I/O" route. Many of these have an asynchronous "aio_*"	1740	"Asynchronous I/O" route. Many of these have an asynchronous "aio_*"
1575	counterpart.	1741	counterpart.
		1742
		1743	$retval = IO::AIO::fexecve $fh, $argv, $envp
		1744	A more-or-less direct equivalent to the POSIX "fexecve" functions,
		1745	which allows you to specify the program to be executed via a file
		1746	descriptor (or handle). Returns -1 and sets errno to "ENOSYS" if not
		1747	available.
		1748
		1749	$retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data =
		1750	undef
		1751	Calls the GNU/Linux mount syscall with the given arguments. All
		1752	except $flags are strings, and if $data is "undef", a "NULL" will be
		1753	passed.
		1754
		1755	The following values for $flags are available:
		1756
		1757	"IO::AIO::MS_RDONLY", "IO::AIO::MS_NOSUID", "IO::AIO::MS_NODEV",
		1758	"IO::AIO::MS_NOEXEC", "IO::AIO::MS_SYNCHRONOUS",
		1759	"IO::AIO::MS_REMOUNT", "IO::AIO::MS_MANDLOCK",
		1760	"IO::AIO::MS_DIRSYNC", "IO::AIO::MS_NOATIME",
		1761	"IO::AIO::MS_NODIRATIME", "IO::AIO::MS_BIND", "IO::AIO::MS_MOVE",
		1762	"IO::AIO::MS_REC", "IO::AIO::MS_SILENT", "IO::AIO::MS_POSIXACL",
		1763	"IO::AIO::MS_UNBINDABLE", "IO::AIO::MS_PRIVATE",
		1764	"IO::AIO::MS_SLAVE", "IO::AIO::MS_SHARED", "IO::AIO::MS_RELATIME",
		1765	"IO::AIO::MS_KERNMOUNT", "IO::AIO::MS_I_VERSION",
		1766	"IO::AIO::MS_STRICTATIME", "IO::AIO::MS_LAZYTIME",
		1767	"IO::AIO::MS_ACTIVE", "IO::AIO::MS_NOUSER", "IO::AIO::MS_RMT_MASK",
		1768	"IO::AIO::MS_MGC_VAL" and "IO::AIO::MS_MGC_MSK".
		1769
		1770	$retval = IO::AIO::umount $path, $flags = 0
		1771	Invokes the GNU/Linux "umount" or "umount2" syscalls. Always calls
		1772	"umount" if $flags is 0, otherwqise always tries to call "umount2".
		1773
		1774	The following $flags are available:
		1775
		1776	"IO::AIO::MNT_FORCE", "IO::AIO::MNT_DETACH", "IO::AIO::MNT_EXPIRE"
		1777	and "IO::AIO::UMOUNT_NOFOLLOW".
		1778
		1779	$numfd = IO::AIO::get_fdlimit
		1780	Tries to find the current file descriptor limit and returns it, or
		1781	"undef" and sets $! in case of an error. The limit is one larger
		1782	than the highest valid file descriptor number.
		1783
		1784	IO::AIO::min_fdlimit [$numfd]
		1785	Try to increase the current file descriptor limit(s) to at least
		1786	$numfd by changing the soft or hard file descriptor resource limit.
		1787	If $numfd is missing, it will try to set a very high limit, although
		1788	this is not recommended when you know the actual minimum that you
		1789	require.
		1790
		1791	If the limit cannot be raised enough, the function makes a
		1792	best-effort attempt to increase the limit as much as possible, using
		1793	various tricks, while still failing. You can query the resulting
		1794	limit using "IO::AIO::get_fdlimit".
		1795
		1796	If an error occurs, returns "undef" and sets $!, otherwise returns
		1797	true.
1576		1798
1577	IO::AIO::sendfile $ofh, $ifh, $offset, $count	1799	IO::AIO::sendfile $ofh, $ifh, $offset, $count
1578	Calls the "eio_sendfile_sync" function, which is like	1800	Calls the "eio_sendfile_sync" function, which is like
1579	"aio_sendfile", but is blocking (this makes most sense if you know	1801	"aio_sendfile", but is blocking (this makes most sense if you know
1580	the input data is likely cached already and the output filehandle is	1802	the input data is likely cached already and the output filehandle is
…		…
1597	details). The following advice constants are available:	1819	details). The following advice constants are available:
1598	"IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",	1820	"IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1599	"IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",	1821	"IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1600	"IO::AIO::MADV_DONTNEED".	1822	"IO::AIO::MADV_DONTNEED".
1601		1823
		1824	If $offset is negative, counts from the end. If $length is negative,
		1825	the remaining length of the $scalar is used. If possible, $length
		1826	will be reduced to fit into the $scalar.
		1827
1602	On systems that do not implement "posix_madvise", this function	1828	On systems that do not implement "posix_madvise", this function
1603	returns ENOSYS, otherwise the return value of "posix_madvise".	1829	returns ENOSYS, otherwise the return value of "posix_madvise".
1604		1830
1605	IO::AIO::mprotect $scalar, $offset, $len, $protect	1831	IO::AIO::mprotect $scalar, $offset, $len, $protect
1606	Simply calls the "mprotect" function on the preferably AIO::mmap'ed	1832	Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1607	$scalar (see its manpage for details). The following protect	1833	$scalar (see its manpage for details). The following protect
1608	constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",	1834	constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1609	"IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".	1835	"IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1610		1836
		1837	If $offset is negative, counts from the end. If $length is negative,
		1838	the remaining length of the $scalar is used. If possible, $length
		1839	will be reduced to fit into the $scalar.
		1840
1611	On systems that do not implement "mprotect", this function returns	1841	On systems that do not implement "mprotect", this function returns
1612	ENOSYS, otherwise the return value of "mprotect".	1842	ENOSYS, otherwise the return value of "mprotect".
1613		1843
1614	IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	1844	IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1615	Memory-maps a file (or anonymous memory range) and attaches it to	1845	Memory-maps a file (or anonymous memory range) and attaches it to
1616	the given $scalar, which will act like a string scalar. Returns true	1846	the given $scalar, which will act like a string scalar. Returns true
1617	on success, and false otherwise.	1847	on success, and false otherwise.
1618		1848
		1849	The scalar must exist, but its contents do not matter - this means
		1850	you cannot use a nonexistant array or hash element. When in doubt,
		1851	"undef" the scalar first.
		1852
1619	The only operations allowed on the scalar are "substr"/"vec" that	1853	The only operations allowed on the mmapped scalar are
1620	don't change the string length, and most read-only operations such	1854	"substr"/"vec", which don't change the string length, and most
1621	as copying it or searching it with regexes and so on.	1855	read-only operations such as copying it or searching it with regexes
		1856	and so on.
1622		1857
1623	Anything else is unsafe and will, at best, result in memory leaks.	1858	Anything else is unsafe and will, at best, result in memory leaks.
1624		1859
1625	The memory map associated with the $scalar is automatically removed	1860	The memory map associated with the $scalar is automatically removed
1626	when the $scalar is destroyed, or when the "IO::AIO::mmap" or	1861	when the $scalar is undef'd or destroyed, or when the
1627	"IO::AIO::munmap" functions are called.	1862	"IO::AIO::mmap" or "IO::AIO::munmap" functions are called on it.
1628		1863
1629	This calls the "mmap"(2) function internally. See your system's	1864	This calls the "mmap"(2) function internally. See your system's
1630	manual page for details on the $length, $prot and $flags parameters.	1865	manual page for details on the $length, $prot and $flags parameters.
1631		1866
1632	The $length must be larger than zero and smaller than the actual	1867	The $length must be larger than zero and smaller than the actual
…		…
1638		1873
1639	$flags can be a combination of "IO::AIO::MAP_SHARED" or	1874	$flags can be a combination of "IO::AIO::MAP_SHARED" or
1640	"IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when	1875	"IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1641	not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to	1876	not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to
1642	"MAP_ANON" if your system only provides this constant),	1877	"MAP_ANON" if your system only provides this constant),
		1878	"IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE",
1643	"IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",	1879	"IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK",
1644	"IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE",	1880	"IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN",
1645	"IO::AIO::MAP_NONBLOCK", "IO::AIO::MAP_FIXED",
1646	"IO::AIO::MAP_GROWSDOWN", "IO::AIO::MAP_32BIT",
1647	"IO::AIO::MAP_HUGETLB" or "IO::AIO::MAP_STACK".	1881	"IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_STACK",
		1882	"IO::AIO::MAP_FIXED_NOREPLACE", "IO::AIO::MAP_SHARED_VALIDATE",
		1883	"IO::AIO::MAP_SYNC" or "IO::AIO::MAP_UNINITIALIZED".
1648		1884
1649	If $fh is "undef", then a file descriptor of -1 is passed.	1885	If $fh is "undef", then a file descriptor of -1 is passed.
1650		1886
1651	$offset is the offset from the start of the file - it generally must	1887	$offset is the offset from the start of the file - it generally must
1652	be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.	1888	be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
…		…
1664		1900
1665	my $fast_md5 = md5 $data;	1901	my $fast_md5 = md5 $data;
1666		1902
1667	IO::AIO::munmap $scalar	1903	IO::AIO::munmap $scalar
1668	Removes a previous mmap and undefines the $scalar.	1904	Removes a previous mmap and undefines the $scalar.
		1905
		1906	IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[,
		1907	$new_address = 0]
		1908	Calls the Linux-specific mremap(2) system call. The $scalar must
		1909	have been mapped by "IO::AIO::mmap", and $flags must currently
		1910	either be 0 or "IO::AIO::MREMAP_MAYMOVE".
		1911
		1912	Returns true if successful, and false otherwise. If the underlying
		1913	mmapped region has changed address, then the true value has the
		1914	numerical value 1, otherwise it has the numerical value 0:
		1915
		1916	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		1917	or die "mremap: $!";
		1918
		1919	if ($success*1) {
		1920	warn "scalar has chanegd address in memory\n";
		1921	}
		1922
		1923	"IO::AIO::MREMAP_FIXED" and the $new_address argument are currently
		1924	implemented, but not supported and might go away in a future
		1925	version.
		1926
		1927	On systems where this call is not supported or is not emulated, this
		1928	call returns falls and sets $! to "ENOSYS".
		1929
		1930	IO::AIO::mlockall $flags
		1931	Calls the "eio_mlockall_sync" function, which is like
		1932	"aio_mlockall", but is blocking.
1669		1933
1670	IO::AIO::munlock $scalar, $offset = 0, $length = undef	1934	IO::AIO::munlock $scalar, $offset = 0, $length = undef
1671	Calls the "munlock" function, undoing the effects of a previous	1935	Calls the "munlock" function, undoing the effects of a previous
1672	"aio_mlock" call (see its description for details).	1936	"aio_mlock" call (see its description for details).
1673		1937
1674	IO::AIO::munlockall	1938	IO::AIO::munlockall
1675	Calls the "munlockall" function.	1939	Calls the "munlockall" function.
1676		1940
1677	On systems that do not implement "munlockall", this function returns	1941	On systems that do not implement "munlockall", this function returns
1678	ENOSYS, otherwise the return value of "munlockall".	1942	ENOSYS, otherwise the return value of "munlockall".
		1943
		1944	$fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
		1945	Uses the GNU/Linux accept4(2) syscall, if available, to accept a
		1946	socket and return the new file handle on success, or sets $! and
		1947	returns "undef" on error.
		1948
		1949	The remote name of the new socket will be stored in $sockaddr, which
		1950	will be extended to allow for at least $sockaddr_maxlen octets. If
		1951	the socket name does not fit into $sockaddr_maxlen octets, this is
		1952	signaled by returning a longer string in $sockaddr, which might or
		1953	might not be truncated.
		1954
		1955	To accept name-less sockets, use "undef" for $sockaddr and 0 for
		1956	$sockaddr_maxlen.
		1957
		1958	The main reasons to use this syscall rather than portable accept(2)
		1959	are that you can specify "SOCK_NONBLOCK" and/or "SOCK_CLOEXEC" flags
		1960	and you can accept name-less sockets by specifying 0 for
		1961	$sockaddr_maxlen, which is sadly not possible with perl's interface
		1962	to "accept".
1679		1963
1680	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags	1964	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1681	Calls the GNU/Linux splice(2) syscall, if available. If $r_off or	1965	Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1682	$w_off are "undef", then "NULL" is passed for these, otherwise they	1966	$w_off are "undef", then "NULL" is passed for these, otherwise they
1683	should be the file offset.	1967	should be the file offset.
…		…
1718		2002
1719	Please refer to pipe2(2) for more info on the $flags, but at the	2003	Please refer to pipe2(2) for more info on the $flags, but at the
1720	time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"	2004	time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"
1721	and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were	2005	and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
1722	supported.	2006	supported.
		2007
		2008	Example: create a pipe race-free w.r.t. threads and fork:
		2009
		2010	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2011	or die "pipe2: $!\n";
		2012
		2013	$fh = IO::AIO::memfd_create $pathname[, $flags]
		2014	This is a direct interface to the Linux memfd_create(2) system call.
		2015	The (unhelpful) default for $flags is 0, but your default should be
		2016	"IO::AIO::MFD_CLOEXEC".
		2017
		2018	On success, the new memfd filehandle is returned, otherwise returns
		2019	"undef". If the memfd_create syscall is missing, fails with
		2020	"ENOSYS".
		2021
		2022	Please refer to memfd_create(2) for more info on this call.
		2023
		2024	The following $flags values are available: "IO::AIO::MFD_CLOEXEC",
		2025	"IO::AIO::MFD_ALLOW_SEALING", "IO::AIO::MFD_HUGETLB",
		2026	"IO::AIO::MFD_HUGETLB_2MB" and "IO::AIO::MFD_HUGETLB_1GB".
		2027
		2028	Example: create a new memfd.
		2029
		2030	my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
		2031	or die "memfd_create: $!\n";
		2032
		2033	$fh = IO::AIO::pidfd_open $pid[, $flags]
		2034	This is an interface to the Linux pidfd_open(2) system call. The
		2035	default for $flags is 0.
		2036
		2037	On success, a new pidfd filehandle is returned (that is already set
		2038	to close-on-exec), otherwise returns "undef". If the syscall is
		2039	missing, fails with "ENOSYS".
		2040
		2041	Example: open pid 6341 as pidfd.
		2042
		2043	my $fh = IO::AIO::pidfd_open 6341
		2044	or die "pidfd_open: $!\n";
		2045
		2046	$status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[,
		2047	$flags]]
		2048	This is an interface to the Linux pidfd_send_signal system call. The
		2049	default for $siginfo is "undef" and the default for $flags is 0.
		2050
		2051	Returns the system call status. If the syscall is missing, fails
		2052	with "ENOSYS".
		2053
		2054	When specified, $siginfo must be a reference to a hash with one or
		2055	more of the following members:
		2056
		2057	code - the "si_code" member
		2058	pid - the "si_pid" member
		2059	uid - the "si_uid" member
		2060	value_int - the "si_value.sival_int" member
		2061	value_ptr - the "si_value.sival_ptr" member, specified as an integer
		2062
		2063	Example: send a SIGKILL to the specified process.
		2064
		2065	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
		2066	and die "pidfd_send_signal: $!\n";
		2067
		2068	Example: send a SIGKILL to the specified process with extra data.
		2069
		2070	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
		2071	and die "pidfd_send_signal: $!\n";
		2072
		2073	$fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
		2074	This is an interface to the Linux pidfd_getfd system call. The
		2075	default for $flags is 0.
		2076
		2077	On success, returns a dup'ed copy of the target file descriptor
		2078	(specified as an integer) returned (that is already set to
		2079	close-on-exec), otherwise returns "undef". If the syscall is
		2080	missing, fails with "ENOSYS".
		2081
		2082	Example: get a copy of standard error of another process and print
		2083	soemthing to it.
		2084
		2085	my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
		2086	or die "pidfd_getfd: $!\n";
		2087	print $errfh "stderr\n";
		2088
		2089	$fh = IO::AIO::eventfd [$initval, [$flags]]
		2090	This is a direct interface to the Linux eventfd(2) system call. The
		2091	(unhelpful) defaults for $initval and $flags are 0 for both.
		2092
		2093	On success, the new eventfd filehandle is returned, otherwise
		2094	returns "undef". If the eventfd syscall is missing, fails with
		2095	"ENOSYS".
		2096
		2097	Please refer to eventfd(2) for more info on this call.
		2098
		2099	The following symbol flag values are available:
		2100	"IO::AIO::EFD_CLOEXEC", "IO::AIO::EFD_NONBLOCK" and
		2101	"IO::AIO::EFD_SEMAPHORE" (Linux 2.6.30).
		2102
		2103	Example: create a new eventfd filehandle:
		2104
		2105	$fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
		2106	or die "eventfd: $!\n";
		2107
		2108	$fh = IO::AIO::timerfd_create $clockid[, $flags]
		2109	This is a direct interface to the Linux timerfd_create(2) system
		2110	call. The (unhelpful) default for $flags is 0, but your default
		2111	should be "IO::AIO::TFD_CLOEXEC".
		2112
		2113	On success, the new timerfd filehandle is returned, otherwise
		2114	returns "undef". If the timerfd_create syscall is missing, fails
		2115	with "ENOSYS".
		2116
		2117	Please refer to timerfd_create(2) for more info on this call.
		2118
		2119	The following $clockid values are available:
		2120	"IO::AIO::CLOCK_REALTIME", "IO::AIO::CLOCK_MONOTONIC"
		2121	"IO::AIO::CLOCK_CLOCK_BOOTTIME" (Linux 3.15)
		2122	"IO::AIO::CLOCK_CLOCK_REALTIME_ALARM" (Linux 3.11) and
		2123	"IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM" (Linux 3.11).
		2124
		2125	The following $flags values are available (Linux 2.6.27):
		2126	"IO::AIO::TFD_NONBLOCK" and "IO::AIO::TFD_CLOEXEC".
		2127
		2128	Example: create a new timerfd and set it to one-second repeated
		2129	alarms, then wait for two alarms:
		2130
		2131	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2132	or die "timerfd_create: $!\n";
		2133
		2134	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2135	or die "timerfd_settime: $!\n";
		2136
		2137	for (1..2) {
		2138	8 == sysread $fh, my $buf, 8
		2139	or die "timerfd read failure\n";
		2140
		2141	printf "number of expirations (likely 1): %d\n",
		2142	unpack "Q", $buf;
		2143	}
		2144
		2145	($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags,
		2146	$new_interval, $nbw_value
		2147	This is a direct interface to the Linux timerfd_settime(2) system
		2148	call. Please refer to its manpage for more info on this call.
		2149
		2150	The new itimerspec is specified using two (possibly fractional)
		2151	second values, $new_interval and $new_value).
		2152
		2153	On success, the current interval and value are returned (as per
		2154	"timerfd_gettime"). On failure, the empty list is returned.
		2155
		2156	The following $flags values are available:
		2157	"IO::AIO::TFD_TIMER_ABSTIME" and "IO::AIO::TFD_TIMER_CANCEL_ON_SET".
		2158
		2159	See "IO::AIO::timerfd_create" for a full example.
		2160
		2161	($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2162	This is a direct interface to the Linux timerfd_gettime(2) system
		2163	call. Please refer to its manpage for more info on this call.
		2164
		2165	On success, returns the current values of interval and value for the
		2166	given timerfd (as potentially fractional second values). On failure,
		2167	the empty list is returned.
1723		2168
1724	EVENT LOOP INTEGRATION	2169	EVENT LOOP INTEGRATION
1725	It is recommended to use AnyEvent::AIO to integrate IO::AIO	2170	It is recommended to use AnyEvent::AIO to integrate IO::AIO
1726	automatically into many event loops:	2171	automatically into many event loops:
1727		2172
…		…
1777	forking, if "IO::AIO" was used in the parent. Calling it while	2222	forking, if "IO::AIO" was used in the parent. Calling it while
1778	IO::AIO is active in the process will result in undefined behaviour.	2223	IO::AIO is active in the process will result in undefined behaviour.
1779	Calling it at any time will also result in any undefined (by POSIX)	2224	Calling it at any time will also result in any undefined (by POSIX)
1780	behaviour.	2225	behaviour.
1781		2226
		2227	LINUX-SPECIFIC CALLS
		2228	When a call is documented as "linux-specific" then this means it
		2229	originated on GNU/Linux. "IO::AIO" will usually try to autodetect the
		2230	availability and compatibility of such calls regardless of the platform
		2231	it is compiled on, so platforms such as FreeBSD which often implement
		2232	these calls will work. When in doubt, call them and see if they fail wth
		2233	"ENOSYS".
		2234
1782	MEMORY USAGE	2235	MEMORY USAGE
1783	Per-request usage:	2236	Per-request usage:
1784		2237
1785	Each aio request uses - depending on your architecture - around 100-200	2238	Each aio request uses - depending on your architecture - around 100-200
1786	bytes of memory. In addition, stat requests need a stat buffer (possibly	2239	bytes of memory. In addition, stat requests need a stat buffer (possibly
…		…
1796	In the execution phase, some aio requests require more memory for	2249	In the execution phase, some aio requests require more memory for
1797	temporary buffers, and each thread requires a stack and other data	2250	temporary buffers, and each thread requires a stack and other data
1798	structures (usually around 16k-128k, depending on the OS).	2251	structures (usually around 16k-128k, depending on the OS).
1799		2252
1800	KNOWN BUGS	2253	KNOWN BUGS
1801	Known bugs will be fixed in the next release.	2254	Known bugs will be fixed in the next release :)
		2255
		2256	KNOWN ISSUES
		2257	Calls that try to "import" foreign memory areas (such as "IO::AIO::mmap"
		2258	or "IO::AIO::aio_slurp") do not work with generic lvalues, such as
		2259	non-created hash slots or other scalars I didn't think of. It's best to
		2260	avoid such and either use scalar variables or making sure that the
		2261	scalar exists (e.g. by storing "undef") and isn't "funny" (e.g. tied).
		2262
		2263	I am not sure anything can be done about this, so this is considered a
		2264	known issue, rather than a bug.
1802		2265
1803	SEE ALSO	2266	SEE ALSO
1804	AnyEvent::AIO for easy integration into event loops, Coro::AIO for a	2267	AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
1805	more natural syntax.	2268	more natural syntax and IO::FDPass for file descriptor passing.
1806		2269
1807	AUTHOR	2270	AUTHOR
1808	Marc Lehmann <schmorp@schmorp.de>	2271	Marc Lehmann <schmorp@schmorp.de>
1809	http://home.schmorp.de/	2272	http://home.schmorp.de/
1810		2273

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Revision 1.57 by root, Mon Jan 18 11:53:09 2016 UTC vs.
Revision 1.70 by root, Sat Apr 1 02:14:05 2023 UTC