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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.273 by root, Fri Jun 23 22:33:06 2017 UTC vs.
Revision 1.317 by root, Sun Sep 25 16:30:50 2022 UTC

…		…
171	use common::sense;	171	use common::sense;
172		172
173	use base 'Exporter';	173	use base 'Exporter';
174		174
175	BEGIN {	175	BEGIN {
176	our $VERSION = 4.35;	176	our $VERSION = 4.79;
177		177
178	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close	178	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
179	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	179	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
…		…
183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
185	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
186	aio_msync aio_mtouch aio_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
187	aio_statvfs	187	aio_statvfs
		188	aio_slurp
188	aio_wd);	189	aio_wd);
189		190
190	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	191	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
191	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	192	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
192	min_parallel max_parallel max_idle idle_timeout	193	min_parallel max_parallel max_idle idle_timeout
193	nreqs nready npending nthreads	194	nreqs nready npending nthreads
194	max_poll_time max_poll_reqs	195	max_poll_time max_poll_reqs
195	sendfile fadvise madvise	196	sendfile fadvise madvise
196	mmap munmap munlock munlockall);	197	mmap munmap mremap munlock munlockall
		198
		199	accept4 tee splice pipe2 pipesize
		200	fexecve mount umount memfd_create eventfd
		201	timerfd_create timerfd_settime timerfd_gettime
		202	pidfd_open pidfd_send_signal pidfd_getfd);
197		203
198	push @AIO_REQ, qw(aio_busy); # not exported	204	push @AIO_REQ, qw(aio_busy); # not exported
199		205
200	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	206	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
201		207
…		…
277	IO::AIO::idle_timeout $seconds	283	IO::AIO::idle_timeout $seconds
278	IO::AIO::max_outstanding $maxreqs	284	IO::AIO::max_outstanding $maxreqs
279	IO::AIO::nreqs	285	IO::AIO::nreqs
280	IO::AIO::nready	286	IO::AIO::nready
281	IO::AIO::npending	287	IO::AIO::npending
		288	IO::AIO::reinit
		289
		290	$nfd = IO::AIO::get_fdlimit
		291	IO::AIO::min_fdlimit $nfd
282		292
283	IO::AIO::sendfile $ofh, $ifh, $offset, $count	293	IO::AIO::sendfile $ofh, $ifh, $offset, $count
284	IO::AIO::fadvise $fh, $offset, $len, $advice	294	IO::AIO::fadvise $fh, $offset, $len, $advice
		295	IO::AIO::fexecve $fh, $argv, $envp
		296
285	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]	297	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
286	IO::AIO::munmap $scalar	298	IO::AIO::munmap $scalar
		299	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
287	IO::AIO::madvise $scalar, $offset, $length, $advice	300	IO::AIO::madvise $scalar, $offset, $length, $advice
288	IO::AIO::mprotect $scalar, $offset, $length, $protect	301	IO::AIO::mprotect $scalar, $offset, $length, $protect
289	IO::AIO::munlock $scalar, $offset = 0, $length = undef	302	IO::AIO::munlock $scalar, $offset = 0, $length = undef
290	IO::AIO::munlockall	303	IO::AIO::munlockall
		304
		305	# stat extensions
		306	$counter = IO::AIO::st_gen
		307	$seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		308	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		309	$nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		310	$seconds = IO::AIO::st_btimesec
		311	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		312
		313	# very much unportable syscalls
		314	IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
		315	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		316	IO::AIO::tee $r_fh, $w_fh, $length, $flags
		317
		318	$actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		319	($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		320
		321	$fh = IO::AIO::eventfd [$initval, [$flags]]
		322	$fh = IO::AIO::memfd_create $pathname[, $flags]
		323
		324	$fh = IO::AIO::timerfd_create $clockid[, $flags]
		325	($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		326	($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		327
		328	$fh = IO::AIO::pidfd_open $pid[, $flags]
		329	$status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
		330	$fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
		331
		332	$retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data = undef
		333	$retval = IO::AIO::umount $path, $flags = 0
291		334
292	=head2 API NOTES	335	=head2 API NOTES
293		336
294	All the C<aio_*> calls are more or less thin wrappers around the syscall	337	All the C<aio_*> calls are more or less thin wrappers around the syscall
295	with the same name (sans C<aio_>). The arguments are similar or identical,	338	with the same name (sans C<aio_>). The arguments are similar or identical,
…		…
401	following POSIX and non-POSIX constants are available (missing ones on	444	following POSIX and non-POSIX constants are available (missing ones on
402	your system are, as usual, C<0>):	445	your system are, as usual, C<0>):
403		446
404	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	447	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
405	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	448	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
406	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.	449	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
407		450
408		451
409	=item aio_close $fh, $callback->($status)	452	=item aio_close $fh, $callback->($status)
410		453
411	Asynchronously close a file and call the callback with the result	454	Asynchronously close a file and call the callback with the result
…		…
537		580
538	=item aio_stat $fh_or_path, $callback->($status)	581	=item aio_stat $fh_or_path, $callback->($status)
539		582
540	=item aio_lstat $fh, $callback->($status)	583	=item aio_lstat $fh, $callback->($status)
541		584
542	Works like perl's C<stat> or C<lstat> in void context. The callback will	585	Works almost exactly like perl's C<stat> or C<lstat> in void context. The
543	be called after the stat and the results will be available using C<stat _>	586	callback will be called after the stat and the results will be available
544	or C<-s _> etc...	587	using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
		588	and C<-T>).
545		589
546	The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,	590	The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
547	for an explanation.	591	for an explanation.
548		592
549	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	593	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
…		…
556	behaviour).	600	behaviour).
557		601
558	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,	602	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
559	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,	603	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
560	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.	604	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		605
		606	To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
		607	ACCESS>.
561		608
562	Example: Print the length of F</etc/passwd>:	609	Example: Print the length of F</etc/passwd>:
563		610
564	aio_stat "/etc/passwd", sub {	611	aio_stat "/etc/passwd", sub {
565	$_[0] and die "stat failed: $!";	612	$_[0] and die "stat failed: $!";
…		…
609	namemax => 255,	656	namemax => 255,
610	frsize => 1024,	657	frsize => 1024,
611	fsid => 1810	658	fsid => 1810
612	}	659	}
613		660
614	Here is a (likely partial - send me updates!) list of fsid values used by
615	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
616
617	0x0000adf5 adfs
618	0x0000adff affs
619	0x5346414f afs
620	0x09041934 anon-inode filesystem
621	0x00000187 autofs
622	0x42465331 befs
623	0x1badface bfs
624	0x42494e4d binfmt_misc
625	0x9123683e btrfs
626	0x0027e0eb cgroupfs
627	0xff534d42 cifs
628	0x73757245 coda
629	0x012ff7b7 coh
630	0x28cd3d45 cramfs
631	0x453dcd28 cramfs-wend (wrong endianness)
632	0x64626720 debugfs
633	0x00001373 devfs
634	0x00001cd1 devpts
635	0x0000f15f ecryptfs
636	0x00414a53 efs
637	0x0000137d ext
638	0x0000ef53 ext2/ext3/ext4
639	0x0000ef51 ext2
640	0xf2f52010 f2fs
641	0x00004006 fat
642	0x65735546 fuseblk
643	0x65735543 fusectl
644	0x0bad1dea futexfs
645	0x01161970 gfs2
646	0x47504653 gpfs
647	0x00004244 hfs
648	0xf995e849 hpfs
649	0x00c0ffee hostfs
650	0x958458f6 hugetlbfs
651	0x2bad1dea inotifyfs
652	0x00009660 isofs
653	0x000072b6 jffs2
654	0x3153464a jfs
655	0x6b414653 k-afs
656	0x0bd00bd0 lustre
657	0x0000137f minix
658	0x0000138f minix 30 char names
659	0x00002468 minix v2
660	0x00002478 minix v2 30 char names
661	0x00004d5a minix v3
662	0x19800202 mqueue
663	0x00004d44 msdos
664	0x0000564c novell
665	0x00006969 nfs
666	0x6e667364 nfsd
667	0x00003434 nilfs
668	0x5346544e ntfs
669	0x00009fa1 openprom
670	0x7461636F ocfs2
671	0x00009fa0 proc
672	0x6165676c pstorefs
673	0x0000002f qnx4
674	0x68191122 qnx6
675	0x858458f6 ramfs
676	0x52654973 reiserfs
677	0x00007275 romfs
678	0x67596969 rpc_pipefs
679	0x73636673 securityfs
680	0xf97cff8c selinux
681	0x0000517b smb
682	0x534f434b sockfs
683	0x73717368 squashfs
684	0x62656572 sysfs
685	0x012ff7b6 sysv2
686	0x012ff7b5 sysv4
687	0x01021994 tmpfs
688	0x15013346 udf
689	0x00011954 ufs
690	0x54190100 ufs byteswapped
691	0x00009fa2 usbdevfs
692	0x01021997 v9fs
693	0xa501fcf5 vxfs
694	0xabba1974 xenfs
695	0x012ff7b4 xenix
696	0x58465342 xfs
697	0x012fd16d xia
698
699	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	661	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
700		662
701	Works like perl's C<utime> function (including the special case of $atime	663	Works like perl's C<utime> function (including the special case of $atime
702	and $mtime being undef). Fractional times are supported if the underlying	664	and $mtime being undef). Fractional times are supported if the underlying
703	syscalls support them.	665	syscalls support them.
704		666
705	When called with a pathname, uses utimes(2) if available, otherwise	667	When called with a pathname, uses utimensat(2) or utimes(2) if available,
706	utime(2). If called on a file descriptor, uses futimes(2) if available,	668	otherwise utime(2). If called on a file descriptor, uses futimens(2)
707	otherwise returns ENOSYS, so this is not portable.	669	or futimes(2) if available, otherwise returns ENOSYS, so this is not
		670	portable.
708		671
709	Examples:	672	Examples:
710		673
711	# set atime and mtime to current time (basically touch(1)):	674	# set atime and mtime to current time (basically touch(1)):
712	aio_utime "path", undef, undef;	675	aio_utime "path", undef, undef;
…		…
871		834
872	=over 4	835	=over 4
873		836
874	=item IO::AIO::READDIR_DENTS	837	=item IO::AIO::READDIR_DENTS
875		838
876	When this flag is off, then the callback gets an arrayref consisting of	839	Normally the callback gets an arrayref consisting of names only (as
877	names only (as with C<aio_readdir>), otherwise it gets an arrayref with	840	with C<aio_readdir>). If this flag is set, then the callback gets an
878	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	841	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
879	entry in more detail.	842	single directory entry in more detail:
880		843
881	C<$name> is the name of the entry.	844	C<$name> is the name of the entry.
882		845
883	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	846	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
884		847
885	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	848	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
886	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	849	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
887	C<IO::AIO::DT_WHT>.	850	C<IO::AIO::DT_WHT>.
888		851
889	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	852	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
890	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	853	to know, you have to run stat yourself. Also, for speed/memory reasons,
891	scalars are read-only: you can not modify them.	854	the C<$type> scalars are read-only: you must not modify them.
892		855
893	C<$inode> is the inode number (which might not be exact on systems with 64	856	C<$inode> is the inode number (which might not be exact on systems with 64
894	bit inode numbers and 32 bit perls). This field has unspecified content on	857	bit inode numbers and 32 bit perls). This field has unspecified content on
895	systems that do not deliver the inode information.	858	systems that do not deliver the inode information.
896		859
…		…
907	short names are tried first.	870	short names are tried first.
908		871
909	=item IO::AIO::READDIR_STAT_ORDER	872	=item IO::AIO::READDIR_STAT_ORDER
910		873
911	When this flag is set, then the names will be returned in an order	874	When this flag is set, then the names will be returned in an order
912	suitable for stat()'ing each one. That is, when you plan to stat()	875	suitable for stat()'ing each one. That is, when you plan to stat() most or
913	all files in the given directory, then the returned order will likely	876	all files in the given directory, then the returned order will likely be
914	be fastest.	877	faster.
915		878
916	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	879	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
917	the likely dirs come first, resulting in a less optimal stat order.	880	then the likely dirs come first, resulting in a less optimal stat order
		881	for stat'ing all entries, but likely a more optimal order for finding
		882	subdirectories.
918		883
919	=item IO::AIO::READDIR_FOUND_UNKNOWN	884	=item IO::AIO::READDIR_FOUND_UNKNOWN
920		885
921	This flag should not be set when calling C<aio_readdirx>. Instead, it	886	This flag should not be set when calling C<aio_readdirx>. Instead, it
922	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	887	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
924	C<$type>'s are known, which can be used to speed up some algorithms.	889	C<$type>'s are known, which can be used to speed up some algorithms.
925		890
926	=back	891	=back
927		892
928		893
		894	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		895
		896	Opens, reads and closes the given file. The data is put into C<$data>,
		897	which is resized as required.
		898
		899	If C<$offset> is negative, then it is counted from the end of the file.
		900
		901	If C<$length> is zero, then the remaining length of the file is
		902	used. Also, in this case, the same limitations to modifying C<$data> apply
		903	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		904	with C<substr>. If the size of the file is known, specifying a non-zero
		905	C<$length> results in a performance advantage.
		906
		907	This request is similar to the older C<aio_load> request, but since it is
		908	a single request, it might be more efficient to use.
		909
		910	Example: load F</etc/passwd> into C<$passwd>.
		911
		912	my $passwd;
		913	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		914	$_[0] >= 0
		915	or die "/etc/passwd: $!\n";
		916
		917	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		918	print $passwd;
		919	};
		920	IO::AIO::flush;
		921
		922
929	=item aio_load $pathname, $data, $callback->($status)	923	=item aio_load $pathname, $data, $callback->($status)
930		924
931	This is a composite request that tries to fully load the given file into	925	This is a composite request that tries to fully load the given file into
932	memory. Status is the same as with aio_read.	926	memory. Status is the same as with aio_read.
		927
		928	Using C<aio_slurp> might be more efficient, as it is a single request.
933		929
934	=cut	930	=cut
935		931
936	sub aio_load($$;$) {	932	sub aio_load($$;$) {
937	my ($path, undef, $cb) = @_;	933	my ($path, undef, $cb) = @_;
…		…
957	=item aio_copy $srcpath, $dstpath, $callback->($status)	953	=item aio_copy $srcpath, $dstpath, $callback->($status)
958		954
959	Try to copy the I<file> (directories not supported as either source or	955	Try to copy the I<file> (directories not supported as either source or
960	destination) from C<$srcpath> to C<$dstpath> and call the callback with	956	destination) from C<$srcpath> to C<$dstpath> and call the callback with
961	a status of C<0> (ok) or C<-1> (error, see C<$!>).	957	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		958
		959	Existing destination files will be truncated.
962		960
963	This is a composite request that creates the destination file with	961	This is a composite request that creates the destination file with
964	mode 0200 and copies the contents of the source file into it using	962	mode 0200 and copies the contents of the source file into it using
965	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	963	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
966	uid/gid, in that order.	964	uid/gid, in that order.
…		…
1076	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1074	Scans a directory (similar to C<aio_readdir>) but additionally tries to
1077	efficiently separate the entries of directory C<$path> into two sets of	1075	efficiently separate the entries of directory C<$path> into two sets of
1078	names, directories you can recurse into (directories), and ones you cannot	1076	names, directories you can recurse into (directories), and ones you cannot
1079	recurse into (everything else, including symlinks to directories).	1077	recurse into (everything else, including symlinks to directories).
1080		1078
1081	C<aio_scandir> is a composite request that creates of many sub requests_	1079	C<aio_scandir> is a composite request that generates many sub requests.
1082	C<$maxreq> specifies the maximum number of outstanding aio requests that	1080	C<$maxreq> specifies the maximum number of outstanding aio requests that
1083	this function generates. If it is C<< <= 0 >>, then a suitable default	1081	this function generates. If it is C<< <= 0 >>, then a suitable default
1084	will be chosen (currently 4).	1082	will be chosen (currently 4).
1085		1083
1086	On error, the callback is called without arguments, otherwise it receives	1084	On error, the callback is called without arguments, otherwise it receives
…		…
1150	aioreq_pri $pri;	1148	aioreq_pri $pri;
1151	add $grp aio_stat $wd, sub {	1149	add $grp aio_stat $wd, sub {
1152	return $grp->result () if $_[0];	1150	return $grp->result () if $_[0];
1153	my $now = time;	1151	my $now = time;
1154	my $hash1 = join ":", (stat _)[0,1,3,7,9];	1152	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		1153	my $rdxflags = READDIR_DIRS_FIRST;
		1154
		1155	if ((stat _)[3] < 2) {
		1156	# at least one non-POSIX filesystem exists
		1157	# that returns useful DT_type values: btrfs,
		1158	# so optimise for this here by requesting dents
		1159	$rdxflags \|= READDIR_DENTS;
		1160	}
1155		1161
1156	# read the directory entries	1162	# read the directory entries
1157	aioreq_pri $pri;	1163	aioreq_pri $pri;
1158	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {	1164	add $grp aio_readdirx $wd, $rdxflags, sub {
1159	my $entries = shift	1165	my ($entries, $flags) = @_
1160	or return $grp->result ();	1166	or return $grp->result ();
		1167
		1168	if ($rdxflags & READDIR_DENTS) {
		1169	# if we requested type values, see if we can use them directly.
		1170
		1171	# if there were any DT_UNKNOWN entries then we assume we
		1172	# don't know. alternatively, we could assume that if we get
		1173	# one DT_DIR, then all directories are indeed marked with
		1174	# DT_DIR, but this seems not required for btrfs, and this
		1175	# is basically the "btrfs can't get it's act together" code
		1176	# branch.
		1177	unless ($flags & READDIR_FOUND_UNKNOWN) {
		1178	# now we have valid DT_ information for all entries,
		1179	# so use it as an optimisation without further stat's.
		1180	# they must also all be at the beginning of @$entries
		1181	# by now.
		1182
		1183	my $dirs;
		1184
		1185	if (@$entries) {
		1186	for (0 .. $#$entries) {
		1187	if ($entries->[$_][1] != DT_DIR) {
		1188	# splice out directories
		1189	$dirs = [splice @$entries, 0, $_];
		1190	last;
		1191	}
		1192	}
		1193
		1194	# if we didn't find any non-dir, then all entries are dirs
		1195	unless ($dirs) {
		1196	($dirs, $entries) = ($entries, []);
		1197	}
		1198	} else {
		1199	# directory is empty, so there are no sbdirs
		1200	$dirs = [];
		1201	}
		1202
		1203	# either splice'd the directories out or the dir was empty.
		1204	# convert dents to filenames
		1205	$_ = $_->[0] for @$dirs;
		1206	$_ = $_->[0] for @$entries;
		1207
		1208	return $grp->result ($dirs, $entries);
		1209	}
		1210
		1211	# cannot use, so return to our old ways
		1212	# by pretending we only scanned for names.
		1213	$_ = $_->[0] for @$entries;
		1214	}
1161		1215
1162	# stat the dir another time	1216	# stat the dir another time
1163	aioreq_pri $pri;	1217	aioreq_pri $pri;
1164	add $grp aio_stat $wd, sub {	1218	add $grp aio_stat $wd, sub {
1165	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1219	my $hash2 = join ":", (stat _)[0,1,3,7,9];
…		…
1271	So in general, you should only use these calls for things that do	1325	So in general, you should only use these calls for things that do
1272	(filesystem) I/O, not for things that wait for other events (network,	1326	(filesystem) I/O, not for things that wait for other events (network,
1273	other processes), although if you are careful and know what you are doing,	1327	other processes), although if you are careful and know what you are doing,
1274	you still can.	1328	you still can.
1275		1329
1276	The following constants are available (missing ones are, as usual C<0>):	1330	The following constants are available and can be used for normal C<ioctl>
		1331	and C<fcntl> as well (missing ones are, as usual C<0>):
1277		1332
1278	C<F_DUPFD_CLOEXEC>,	1333	C<F_DUPFD_CLOEXEC>,
1279		1334
1280	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,	1335	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1281		1336
1282	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.	1337	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1338
		1339	C<F_ADD_SEALS>, C<F_GET_SEALS>, C<F_SEAL_SEAL>, C<F_SEAL_SHRINK>, C<F_SEAL_GROW> and
		1340	C<F_SEAL_WRITE>.
1283		1341
1284	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,	1342	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1285	C<FS_IOC_FIEMAP>.	1343	C<FS_IOC_FIEMAP>.
1286		1344
1287	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,	1345	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
…		…
1295		1353
1296	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,	1354	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1297	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,	1355	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1298	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,	1356	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1299	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,	1357	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
		1358
		1359	C<BLKROSET>, C<BLKROGET>, C<BLKRRPART>, C<BLKGETSIZE>, C<BLKFLSBUF>, C<BLKRASET>,
		1360	C<BLKRAGET>, C<BLKFRASET>, C<BLKFRAGET>, C<BLKSECTSET>, C<BLKSECTGET>, C<BLKSSZGET>,
		1361	C<BLKBSZGET>, C<BLKBSZSET>, C<BLKGETSIZE64>,
		1362
1300		1363
1301	=item aio_sync $callback->($status)	1364	=item aio_sync $callback->($status)
1302		1365
1303	Asynchronously call sync and call the callback when finished.	1366	Asynchronously call sync and call the callback when finished.
1304		1367
…		…
1426	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;	1489	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1427	aio_mlock $data; # mlock in background	1490	aio_mlock $data; # mlock in background
1428		1491
1429	=item aio_mlockall $flags, $callback->($status)	1492	=item aio_mlockall $flags, $callback->($status)
1430		1493
1431	Calls the C<mlockall> function with the given C<$flags> (a combination of	1494	Calls the C<mlockall> function with the given C<$flags> (a
1432	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).	1495	combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
		1496	C<IO::AIO::MCL_ONFAULT>).
1433		1497
1434	On systems that do not implement C<mlockall>, this function returns C<-1>	1498	On systems that do not implement C<mlockall>, this function returns C<-1>
1435	and sets errno to C<ENOSYS>.	1499	and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
		1500	by the system result in a return value of C<-1> with errno being set to
		1501	C<EINVAL>.
1436		1502
1437	Note that the corresponding C<munlockall> is synchronous and is	1503	Note that the corresponding C<munlockall> is synchronous and is
1438	documented under L<MISCELLANEOUS FUNCTIONS>.	1504	documented under L<MISCELLANEOUS FUNCTIONS>.
1439		1505
1440	Example: asynchronously lock all current and future pages into memory.	1506	Example: asynchronously lock all current and future pages into memory.
…		…
1479	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,	1545	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1480	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,	1546	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1481	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or	1547	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1482	C<IO::AIO::FIEMAP_EXTENT_SHARED>.	1548	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1483		1549
1484	At the time of this writing (Linux 3.2), this requets is unreliable unless	1550	At the time of this writing (Linux 3.2), this request is unreliable unless
1485	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing	1551	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1486	it to return all extents of a range for files with large number of	1552	it to return all extents of a range for files with a large number of
1487	extents. The code works around all these issues if C<$count> is undef.	1553	extents. The code (only) works around all these issues if C<$count> is
		1554	C<undef>.
1488		1555
1489	=item aio_group $callback->(...)	1556	=item aio_group $callback->(...)
1490		1557
1491	This is a very special aio request: Instead of doing something, it is a	1558	This is a very special aio request: Instead of doing something, it is a
1492	container for other aio requests, which is useful if you want to bundle	1559	container for other aio requests, which is useful if you want to bundle
…		…
1605	There are some caveats: when directories get renamed (or deleted), the	1672	There are some caveats: when directories get renamed (or deleted), the
1606	pathname string doesn't change, so will point to the new directory (or	1673	pathname string doesn't change, so will point to the new directory (or
1607	nowhere at all), while the directory fd, if available on the system,	1674	nowhere at all), while the directory fd, if available on the system,
1608	will still point to the original directory. Most functions accepting a	1675	will still point to the original directory. Most functions accepting a
1609	pathname will use the directory fd on newer systems, and the string on	1676	pathname will use the directory fd on newer systems, and the string on
1610	older systems. Some functions (such as realpath) will always rely on the	1677	older systems. Some functions (such as C<aio_realpath>) will always rely on
1611	string form of the pathname.	1678	the string form of the pathname.
1612		1679
1613	So this functionality is mainly useful to get some protection against	1680	So this functionality is mainly useful to get some protection against
1614	C<chdir>, to easily get an absolute path out of a relative path for future	1681	C<chdir>, to easily get an absolute path out of a relative path for future
1615	reference, and to speed up doing many operations in the same directory	1682	reference, and to speed up doing many operations in the same directory
1616	(e.g. when stat'ing all files in a directory).	1683	(e.g. when stat'ing all files in a directory).
…		…
1633	C<aio_wd> callback, as future requests using the value will fail in the	1700	C<aio_wd> callback, as future requests using the value will fail in the
1634	expected way.	1701	expected way.
1635		1702
1636	=item IO::AIO::CWD	1703	=item IO::AIO::CWD
1637		1704
1638	This is a compiletime constant (object) that represents the process	1705	This is a compile time constant (object) that represents the process
1639	current working directory.	1706	current working directory.
1640		1707
1641	Specifying this object as working directory object for a pathname is as if	1708	Specifying this object as working directory object for a pathname is as if
1642	the pathname would be specified directly, without a directory object. For	1709	the pathname would be specified directly, without a directory object. For
1643	example, these calls are functionally identical:	1710	example, these calls are functionally identical:
…		…
1824	The default value for the limit is C<0>, but note that setting a feeder	1891	The default value for the limit is C<0>, but note that setting a feeder
1825	automatically bumps it up to C<2>.	1892	automatically bumps it up to C<2>.
1826		1893
1827	=back	1894	=back
1828		1895
		1896
1829	=head2 SUPPORT FUNCTIONS	1897	=head2 SUPPORT FUNCTIONS
1830		1898
1831	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1899	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1832		1900
1833	=over 4	1901	=over 4
…		…
1898	Strictly equivalent to:	1966	Strictly equivalent to:
1899		1967
1900	IO::AIO::poll_wait, IO::AIO::poll_cb	1968	IO::AIO::poll_wait, IO::AIO::poll_cb
1901	while IO::AIO::nreqs;	1969	while IO::AIO::nreqs;
1902		1970
		1971	This function can be useful at program aborts, to make sure outstanding
		1972	I/O has been done (C<IO::AIO> uses an C<END> block which already calls
		1973	this function on normal exits), or when you are merely using C<IO::AIO>
		1974	for its more advanced functions, rather than for async I/O, e.g.:
		1975
		1976	my ($dirs, $nondirs);
		1977	IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
		1978	IO::AIO::flush;
		1979	# $dirs, $nondirs are now set
		1980
1903	=item IO::AIO::max_poll_reqs $nreqs	1981	=item IO::AIO::max_poll_reqs $nreqs
1904		1982
1905	=item IO::AIO::max_poll_time $seconds	1983	=item IO::AIO::max_poll_time $seconds
1906		1984
1907	These set the maximum number of requests (default C<0>, meaning infinity)	1985	These set the maximum number of requests (default C<0>, meaning infinity)
…		…
1933	poll => 'r', nice => 1,	2011	poll => 'r', nice => 1,
1934	cb => &IO::AIO::poll_cb);	2012	cb => &IO::AIO::poll_cb);
1935		2013
1936	=back	2014	=back
1937		2015
		2016
1938	=head3 CONTROLLING THE NUMBER OF THREADS	2017	=head3 CONTROLLING THE NUMBER OF THREADS
1939		2018
1940	=over	2019	=over
1941		2020
1942	=item IO::AIO::min_parallel $nthreads	2021	=item IO::AIO::min_parallel $nthreads
…		…
2003	longer exceeded.	2082	longer exceeded.
2004		2083
2005	In other words, this setting does not enforce a queue limit, but can be	2084	In other words, this setting does not enforce a queue limit, but can be
2006	used to make poll functions block if the limit is exceeded.	2085	used to make poll functions block if the limit is exceeded.
2007		2086
2008	This is a very bad function to use in interactive programs because it	2087	This is a bad function to use in interactive programs because it blocks,
2009	blocks, and a bad way to reduce concurrency because it is inexact: Better	2088	and a bad way to reduce concurrency because it is inexact. If you need to
		2089	issue many requests without being able to call a poll function on demand,
2010	use an C<aio_group> together with a feed callback.	2090	it is better to use an C<aio_group> together with a feed callback.
2011		2091
2012	Its main use is in scripts without an event loop - when you want to stat	2092	Its main use is in scripts without an event loop - when you want to stat a
2013	a lot of files, you can write somehting like this:	2093	lot of files, you can write something like this:
2014		2094
2015	IO::AIO::max_outstanding 32;	2095	IO::AIO::max_outstanding 32;
2016		2096
2017	for my $path (...) {	2097	for my $path (...) {
2018	aio_stat $path , ...;	2098	aio_stat $path , ...;
2019	IO::AIO::poll_cb;	2099	IO::AIO::poll_cb;
2020	}	2100	}
2021		2101
2022	IO::AIO::flush;	2102	IO::AIO::flush;
2023		2103
2024	The call to C<poll_cb> inside the loop will normally return instantly, but	2104	The call to C<poll_cb> inside the loop will normally return instantly,
2025	as soon as more thna C<32> reqeusts are in-flight, it will block until	2105	allowing the loop to progress, but as soon as more than C<32> requests
2026	some requests have been handled. This keeps the loop from pushing a large	2106	are in-flight, it will block until some requests have been handled. This
2027	number of C<aio_stat> requests onto the queue.	2107	keeps the loop from pushing a large number of C<aio_stat> requests onto
		2108	the queue (which, with many paths to stat, can use up a lot of memory).
2028		2109
2029	The default value for C<max_outstanding> is very large, so there is no	2110	The default value for C<max_outstanding> is very large, so there is no
2030	practical limit on the number of outstanding requests.	2111	practical limit on the number of outstanding requests.
2031		2112
2032	=back	2113	=back
2033		2114
		2115
2034	=head3 STATISTICAL INFORMATION	2116	=head3 STATISTICAL INFORMATION
2035		2117
2036	=over	2118	=over
2037		2119
2038	=item IO::AIO::nreqs	2120	=item IO::AIO::nreqs
…		…
2054		2136
2055	Returns the number of requests currently in the pending state (executed,	2137	Returns the number of requests currently in the pending state (executed,
2056	but not yet processed by poll_cb).	2138	but not yet processed by poll_cb).
2057		2139
2058	=back	2140	=back
		2141
		2142
		2143	=head3 SUBSECOND STAT TIME ACCESS
		2144
		2145	Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
		2146	generally find access/modification and change times with subsecond time
		2147	accuracy of the system supports it, but perl's built-in functions only
		2148	return the integer part.
		2149
		2150	The following functions return the timestamps of the most recent
		2151	stat with subsecond precision on most systems and work both after
		2152	C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
		2153	value is only meaningful after a successful C<stat>/C<lstat> call, or
		2154	during/after a successful C<aio_stat>/C<aio_lstat> callback.
		2155
		2156	This is similar to the L<Time::HiRes> C<stat> functions, but can return
		2157	full resolution without rounding and work with standard perl C<stat>,
		2158	alleviating the need to call the special C<Time::HiRes> functions, which
		2159	do not act like their perl counterparts.
		2160
		2161	On operating systems or file systems where subsecond time resolution is
		2162	not supported or could not be detected, a fractional part of C<0> is
		2163	returned, so it is always safe to call these functions.
		2164
		2165	=over 4
		2166
		2167	=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		2168
		2169	Return the access, modication, change or birth time, respectively,
		2170	including fractional part. Due to the limited precision of floating point,
		2171	the accuracy on most platforms is only a bit better than milliseconds
		2172	for times around now - see the I<nsec> function family, below, for full
		2173	accuracy.
		2174
		2175	File birth time is only available when the OS and perl support it (on
		2176	FreeBSD and NetBSD at the time of this writing, although support is
		2177	adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
		2178	it). On systems where it isn't available, C<0> is currently returned, but
		2179	this might change to C<undef> in a future version.
		2180
		2181	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		2182
		2183	Returns access, modification, change and birth time all in one go, and
		2184	maybe more times in the future version.
		2185
		2186	=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		2187
		2188	Return the fractional access, modifcation, change or birth time, in nanoseconds,
		2189	as an integer in the range C<0> to C<999999999>.
		2190
		2191	Note that no accessors are provided for access, modification and
		2192	change times - you need to get those from C<stat _> if required (C<int
		2193	IO::AIO::st_atime> and so on will I<not> generally give you the correct
		2194	value).
		2195
		2196	=item $seconds = IO::AIO::st_btimesec
		2197
		2198	The (integral) seconds part of the file birth time, if available.
		2199
		2200	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		2201
		2202	Like the functions above, but returns all four times in one go (and maybe
		2203	more in future versions).
		2204
		2205	=item $counter = IO::AIO::st_gen
		2206
		2207	Returns the generation counter (in practice this is just a random number)
		2208	of the file. This is only available on platforms which have this member in
		2209	their C<struct stat> (most BSDs at the time of this writing) and generally
		2210	only to the root usert. If unsupported, C<0> is returned, but this might
		2211	change to C<undef> in a future version.
		2212
		2213	=back
		2214
		2215	Example: print the high resolution modification time of F</etc>, using
		2216	C<stat>, and C<IO::AIO::aio_stat>.
		2217
		2218	if (stat "/etc") {
		2219	printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
		2220	}
		2221
		2222	IO::AIO::aio_stat "/etc", sub {
		2223	$_[0]
		2224	and return;
		2225
		2226	printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
		2227	};
		2228
		2229	IO::AIO::flush;
		2230
		2231	Output of the awbove on my system, showing reduced and full accuracy:
		2232
		2233	stat(/etc) mtime: 1534043702.020808
		2234	aio_stat(/etc) mtime: 1534043702.020807792
		2235
2059		2236
2060	=head3 MISCELLANEOUS FUNCTIONS	2237	=head3 MISCELLANEOUS FUNCTIONS
2061		2238
2062	IO::AIO implements some functions that are useful when you want to use	2239	IO::AIO implements some functions that are useful when you want to use
2063	some "Advanced I/O" function not available to in Perl, without going the	2240	some "Advanced I/O" function not available to in Perl, without going the
2064	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>	2241	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2065	counterpart.	2242	counterpart.
2066		2243
2067	=over 4	2244	=over 4
		2245
		2246	=item $retval = IO::AIO::fexecve $fh, $argv, $envp
		2247
		2248	A more-or-less direct equivalent to the POSIX C<fexecve> functions, which
		2249	allows you to specify the program to be executed via a file descriptor (or
		2250	handle). Returns C<-1> and sets errno to C<ENOSYS> if not available.
		2251
		2252	=item $retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data = undef
		2253
		2254	Calls the GNU/Linux mount syscall with the given arguments. All except
		2255	C<$flags> are strings, and if C<$data> is C<undef>, a C<NULL> will be
		2256	passed.
		2257
		2258	The following values for C<$flags> are available:
		2259
		2260	C<IO::AIO::MS_RDONLY>, C<IO::AIO::MS_NOSUID>, C<IO::AIO::MS_NODEV>, C<IO::AIO::MS_NOEXEC>, C<IO::AIO::MS_SYNCHRONOUS>,
		2261	C<IO::AIO::MS_REMOUNT>, C<IO::AIO::MS_MANDLOCK>, C<IO::AIO::MS_DIRSYNC>, C<IO::AIO::MS_NOATIME>,
		2262	C<IO::AIO::MS_NODIRATIME>, C<IO::AIO::MS_BIND>, C<IO::AIO::MS_MOVE>, C<IO::AIO::MS_REC>, C<IO::AIO::MS_SILENT>,
		2263	C<IO::AIO::MS_POSIXACL>, C<IO::AIO::MS_UNBINDABLE>, C<IO::AIO::MS_PRIVATE>, C<IO::AIO::MS_SLAVE>, C<IO::AIO::MS_SHARED>,
		2264	C<IO::AIO::MS_RELATIME>, C<IO::AIO::MS_KERNMOUNT>, C<IO::AIO::MS_I_VERSION>, C<IO::AIO::MS_STRICTATIME>,
		2265	C<IO::AIO::MS_LAZYTIME>, C<IO::AIO::MS_ACTIVE>, C<IO::AIO::MS_NOUSER>, C<IO::AIO::MS_RMT_MASK>, C<IO::AIO::MS_MGC_VAL> and
		2266	C<IO::AIO::MS_MGC_MSK>.
		2267
		2268	=item $retval = IO::AIO::umount $path, $flags = 0
		2269
		2270	Invokes the GNU/Linux C<umount> or C<umount2> syscalls. Always calls
		2271	C<umount> if C<$flags> is C<0>, otherwqise always tries to call
		2272	C<umount2>.
		2273
		2274	The following C<$flags> are available:
		2275
		2276	C<IO::AIO::MNT_FORCE>, C<IO::AIO::MNT_DETACH>, C<IO::AIO::MNT_EXPIRE> and C<IO::AIO::UMOUNT_NOFOLLOW>.
		2277
		2278	=item $numfd = IO::AIO::get_fdlimit
		2279
		2280	Tries to find the current file descriptor limit and returns it, or
		2281	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2282	the highest valid file descriptor number.
		2283
		2284	=item IO::AIO::min_fdlimit [$numfd]
		2285
		2286	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2287	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2288	is missing, it will try to set a very high limit, although this is not
		2289	recommended when you know the actual minimum that you require.
		2290
		2291	If the limit cannot be raised enough, the function makes a best-effort
		2292	attempt to increase the limit as much as possible, using various
		2293	tricks, while still failing. You can query the resulting limit using
		2294	C<IO::AIO::get_fdlimit>.
		2295
		2296	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2297	true.
2068		2298
2069	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2299	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
2070		2300
2071	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2301	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
2072	but is blocking (this makes most sense if you know the input data is	2302	but is blocking (this makes most sense if you know the input data is
…		…
2154	C<IO::AIO::MAP_POPULATE>,	2384	C<IO::AIO::MAP_POPULATE>,
2155	C<IO::AIO::MAP_NONBLOCK>,	2385	C<IO::AIO::MAP_NONBLOCK>,
2156	C<IO::AIO::MAP_FIXED>,	2386	C<IO::AIO::MAP_FIXED>,
2157	C<IO::AIO::MAP_GROWSDOWN>,	2387	C<IO::AIO::MAP_GROWSDOWN>,
2158	C<IO::AIO::MAP_32BIT>,	2388	C<IO::AIO::MAP_32BIT>,
2159	C<IO::AIO::MAP_HUGETLB> or	2389	C<IO::AIO::MAP_HUGETLB>,
2160	C<IO::AIO::MAP_STACK>.	2390	C<IO::AIO::MAP_STACK>,
		2391	C<IO::AIO::MAP_FIXED_NOREPLACE>,
		2392	C<IO::AIO::MAP_SHARED_VALIDATE>,
		2393	C<IO::AIO::MAP_SYNC> or
		2394	C<IO::AIO::MAP_UNINITIALIZED>.
2161		2395
2162	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2396	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2163		2397
2164	C<$offset> is the offset from the start of the file - it generally must be	2398	C<$offset> is the offset from the start of the file - it generally must be
2165	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2399	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
2179		2413
2180	=item IO::AIO::munmap $scalar	2414	=item IO::AIO::munmap $scalar
2181		2415
2182	Removes a previous mmap and undefines the C<$scalar>.	2416	Removes a previous mmap and undefines the C<$scalar>.
2183		2417
		2418	=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
		2419
		2420	Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
		2421	been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
		2422	C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
		2423
		2424	Returns true if successful, and false otherwise. If the underlying mmapped
		2425	region has changed address, then the true value has the numerical value
		2426	C<1>, otherwise it has the numerical value C<0>:
		2427
		2428	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		2429	or die "mremap: $!";
		2430
		2431	if ($success*1) {
		2432	warn "scalar has chanegd address in memory\n";
		2433	}
		2434
		2435	C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
		2436	implemented, but not supported and might go away in a future version.
		2437
		2438	On systems where this call is not supported or is not emulated, this call
		2439	returns falls and sets C<$!> to C<ENOSYS>.
		2440
		2441	=item IO::AIO::mlockall $flags
		2442
		2443	Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
		2444	but is blocking.
		2445
2184	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef	2446	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2185		2447
2186	Calls the C<munlock> function, undoing the effects of a previous	2448	Calls the C<munlock> function, undoing the effects of a previous
2187	C<aio_mlock> call (see its description for details).	2449	C<aio_mlock> call (see its description for details).
2188		2450
…		…
2190		2452
2191	Calls the C<munlockall> function.	2453	Calls the C<munlockall> function.
2192		2454
2193	On systems that do not implement C<munlockall>, this function returns	2455	On systems that do not implement C<munlockall>, this function returns
2194	ENOSYS, otherwise the return value of C<munlockall>.	2456	ENOSYS, otherwise the return value of C<munlockall>.
		2457
		2458	=item $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
		2459
		2460	Uses the GNU/Linux C<accept4(2)> syscall, if available, to accept a socket
		2461	and return the new file handle on success, or sets C<$!> and returns
		2462	C<undef> on error.
		2463
		2464	The remote name of the new socket will be stored in C<$sockaddr>, which
		2465	will be extended to allow for at least C<$sockaddr_maxlen> octets. If the
		2466	socket name does not fit into C<$sockaddr_maxlen> octets, this is signaled
		2467	by returning a longer string in C<$sockaddr>, which might or might not be
		2468	truncated.
		2469
		2470	To accept name-less sockets, use C<undef> for C<$sockaddr> and C<0> for
		2471	C<$sockaddr_maxlen>.
		2472
		2473	The main reasons to use this syscall rather than portable C<accept(2)>
		2474	are that you can specify C<SOCK_NONBLOCK> and/or C<SOCK_CLOEXEC>
		2475	flags and you can accept name-less sockets by specifying C<0> for
		2476	C<$sockaddr_maxlen>, which is sadly not possible with perl's interface to
		2477	C<accept>.
2195		2478
2196	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags	2479	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2197		2480
2198	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or	2481	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2199	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they	2482	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
…		…
2237	C<$flags> is non-zero, fails with C<ENOSYS>.	2520	C<$flags> is non-zero, fails with C<ENOSYS>.
2238		2521
2239	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the	2522	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2240	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and	2523	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2241	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.	2524	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2525
		2526	Example: create a pipe race-free w.r.t. threads and fork:
		2527
		2528	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2529	or die "pipe2: $!\n";
		2530
		2531	=item $fh = IO::AIO::memfd_create $pathname[, $flags]
		2532
		2533	This is a direct interface to the Linux L<memfd_create(2)> system
		2534	call. The (unhelpful) default for C<$flags> is C<0>, but your default
		2535	should be C<IO::AIO::MFD_CLOEXEC>.
		2536
		2537	On success, the new memfd filehandle is returned, otherwise returns
		2538	C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
		2539
		2540	Please refer to L<memfd_create(2)> for more info on this call.
		2541
		2542	The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
		2543	C<IO::AIO::MFD_ALLOW_SEALING>, C<IO::AIO::MFD_HUGETLB>,
		2544	C<IO::AIO::MFD_HUGETLB_2MB> and C<IO::AIO::MFD_HUGETLB_1GB>.
		2545
		2546	Example: create a new memfd.
		2547
		2548	my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
		2549	or die "memfd_create: $!\n";
		2550
		2551	=item $fh = IO::AIO::pidfd_open $pid[, $flags]
		2552
		2553	This is an interface to the Linux L<pidfd_open(2)> system call. The
		2554	default for C<$flags> is C<0>.
		2555
		2556	On success, a new pidfd filehandle is returned (that is already set to
		2557	close-on-exec), otherwise returns C<undef>. If the syscall is missing,
		2558	fails with C<ENOSYS>.
		2559
		2560	Example: open pid 6341 as pidfd.
		2561
		2562	my $fh = IO::AIO::pidfd_open 6341
		2563	or die "pidfd_open: $!\n";
		2564
		2565	=item $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
		2566
		2567	This is an interface to the Linux L<pidfd_send_signal> system call. The
		2568	default for C<$siginfo> is C<undef> and the default for C<$flags> is C<0>.
		2569
		2570	Returns the system call status. If the syscall is missing, fails with
		2571	C<ENOSYS>.
		2572
		2573	When specified, C<$siginfo> must be a reference to a hash with one or more
		2574	of the following members:
		2575
		2576	=over
		2577
		2578	=item code - the C<si_code> member
		2579
		2580	=item pid - the C<si_pid> member
		2581
		2582	=item uid - the C<si_uid> member
		2583
		2584	=item value_int - the C<si_value.sival_int> member
		2585
		2586	=item value_ptr - the C<si_value.sival_ptr> member, specified as an integer
		2587
		2588	=back
		2589
		2590	Example: send a SIGKILL to the specified process.
		2591
		2592	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
		2593	and die "pidfd_send_signal: $!\n";
		2594
		2595	Example: send a SIGKILL to the specified process with extra data.
		2596
		2597	my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
		2598	and die "pidfd_send_signal: $!\n";
		2599
		2600	=item $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
		2601
		2602	This is an interface to the Linux L<pidfd_getfd> system call. The default
		2603	for C<$flags> is C<0>.
		2604
		2605	On success, returns a dup'ed copy of the target file descriptor (specified
		2606	as an integer) returned (that is already set to close-on-exec), otherwise
		2607	returns C<undef>. If the syscall is missing, fails with C<ENOSYS>.
		2608
		2609	Example: get a copy of standard error of another process and print soemthing to it.
		2610
		2611	my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
		2612	or die "pidfd_getfd: $!\n";
		2613	print $errfh "stderr\n";
		2614
		2615	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2616
		2617	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2618	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2619
		2620	On success, the new eventfd filehandle is returned, otherwise returns
		2621	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2622
		2623	Please refer to L<eventfd(2)> for more info on this call.
		2624
		2625	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2626	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2627
		2628	Example: create a new eventfd filehandle:
		2629
		2630	$fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
		2631	or die "eventfd: $!\n";
		2632
		2633	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2634
		2635	This is a direct interface to the Linux L<timerfd_create(2)> system
		2636	call. The (unhelpful) default for C<$flags> is C<0>, but your default
		2637	should be C<IO::AIO::TFD_CLOEXEC>.
		2638
		2639	On success, the new timerfd filehandle is returned, otherwise returns
		2640	C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
		2641
		2642	Please refer to L<timerfd_create(2)> for more info on this call.
		2643
		2644	The following C<$clockid> values are
		2645	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2646	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2647	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2648	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2649
		2650	The following C<$flags> values are available (Linux
		2651	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2652
		2653	Example: create a new timerfd and set it to one-second repeated alarms,
		2654	then wait for two alarms:
		2655
		2656	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2657	or die "timerfd_create: $!\n";
		2658
		2659	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2660	or die "timerfd_settime: $!\n";
		2661
		2662	for (1..2) {
		2663	8 == sysread $fh, my $buf, 8
		2664	or die "timerfd read failure\n";
		2665
		2666	printf "number of expirations (likely 1): %d\n",
		2667	unpack "Q", $buf;
		2668	}
		2669
		2670	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2671
		2672	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2673	call. Please refer to its manpage for more info on this call.
		2674
		2675	The new itimerspec is specified using two (possibly fractional) second
		2676	values, C<$new_interval> and C<$new_value>).
		2677
		2678	On success, the current interval and value are returned (as per
		2679	C<timerfd_gettime>). On failure, the empty list is returned.
		2680
		2681	The following C<$flags> values are
		2682	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2683	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2684
		2685	See C<IO::AIO::timerfd_create> for a full example.
		2686
		2687	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2688
		2689	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2690	call. Please refer to its manpage for more info on this call.
		2691
		2692	On success, returns the current values of interval and value for the given
		2693	timerfd (as potentially fractional second values). On failure, the empty
		2694	list is returned.
2242		2695
2243	=back	2696	=back
2244		2697
2245	=cut	2698	=cut
2246		2699
…		…
2312	the process will result in undefined behaviour. Calling it at any time	2765	the process will result in undefined behaviour. Calling it at any time
2313	will also result in any undefined (by POSIX) behaviour.	2766	will also result in any undefined (by POSIX) behaviour.
2314		2767
2315	=back	2768	=back
2316		2769
		2770	=head2 LINUX-SPECIFIC CALLS
		2771
		2772	When a call is documented as "linux-specific" then this means it
		2773	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2774	availability and compatibility of such calls regardless of the platform
		2775	it is compiled on, so platforms such as FreeBSD which often implement
		2776	these calls will work. When in doubt, call them and see if they fail wth
		2777	C<ENOSYS>.
		2778
2317	=head2 MEMORY USAGE	2779	=head2 MEMORY USAGE
2318		2780
2319	Per-request usage:	2781	Per-request usage:
2320		2782
2321	Each aio request uses - depending on your architecture - around 100-200	2783	Each aio request uses - depending on your architecture - around 100-200
…		…
2333	temporary buffers, and each thread requires a stack and other data	2795	temporary buffers, and each thread requires a stack and other data
2334	structures (usually around 16k-128k, depending on the OS).	2796	structures (usually around 16k-128k, depending on the OS).
2335		2797
2336	=head1 KNOWN BUGS	2798	=head1 KNOWN BUGS
2337		2799
2338	Known bugs will be fixed in the next release.	2800	Known bugs will be fixed in the next release :)
		2801
		2802	=head1 KNOWN ISSUES
		2803
		2804	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2805	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2806	non-created hash slots or other scalars I didn't think of. It's best to
		2807	avoid such and either use scalar variables or making sure that the scalar
		2808	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2809
		2810	I am not sure anything can be done about this, so this is considered a
		2811	known issue, rather than a bug.
2339		2812
2340	=head1 SEE ALSO	2813	=head1 SEE ALSO
2341		2814
2342	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2815	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2343	more natural syntax.	2816	more natural syntax and L<IO::FDPass> for file descriptor passing.
2344		2817
2345	=head1 AUTHOR	2818	=head1 AUTHOR
2346		2819
2347	Marc Lehmann <schmorp@schmorp.de>	2820	Marc Lehmann <schmorp@schmorp.de>
2348	http://home.schmorp.de/	2821	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.273 by root, Fri Jun 23 22:33:06 2017 UTC vs. Revision 1.317 by root, Sun Sep 25 16:30:50 2022 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.273 by root, Fri Jun 23 22:33:06 2017 UTC vs.
Revision 1.317 by root, Sun Sep 25 16:30:50 2022 UTC