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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.230 by root, Fri Jul 27 17:24:06 2012 UTC vs.
Revision 1.302 by root, Wed Apr 3 03:03:53 2019 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	IO::AIO - Asynchronous Input/Output	3	IO::AIO - Asynchronous/Advanced Input/Output
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
58	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
59	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
60	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
61	using threads anyway.	61	using threads anyway.
62		62
		63	In addition to asynchronous I/O, this module also exports some rather
		64	arcane interfaces, such as C<madvise> or linux's C<splice> system call,
		65	which is why the C<A> in C<AIO> can also mean I<advanced>.
		66
63	Although the module will work in the presence of other (Perl-) threads,	67	Although the module will work in the presence of other (Perl-) threads,
64	it is currently not reentrant in any way, so use appropriate locking	68	it is currently not reentrant in any way, so use appropriate locking
65	yourself, always call C<poll_cb> from within the same thread, or never	69	yourself, always call C<poll_cb> from within the same thread, or never
66	call C<poll_cb> (or other C<aio_> functions) recursively.	70	call C<poll_cb> (or other C<aio_> functions) recursively.
67		71
68	=head2 EXAMPLE	72	=head2 EXAMPLE
69		73
70	This is a simple example that uses the EV module and loads	74	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	75	F</etc/passwd> asynchronously:
72		76
73	use Fcntl;
74	use EV;	77	use EV;
75	use IO::AIO;	78	use IO::AIO;
76		79
77	# register the IO::AIO callback with EV	80	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	81	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		98
96	# file contents now in $contents	99	# file contents now in $contents
97	print $contents;	100	print $contents;
98		101
99	# exit event loop and program	102	# exit event loop and program
100	EV::unloop;	103	EV::break;
101	};	104	};
102	};	105	};
103		106
104	# possibly queue up other requests, or open GUI windows,	107	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	108	# check for sockets etc. etc.
106		109
107	# process events as long as there are some:	110	# process events as long as there are some:
108	EV::loop;	111	EV::run;
109		112
110	=head1 REQUEST ANATOMY AND LIFETIME	113	=head1 REQUEST ANATOMY AND LIFETIME
111		114
112	Every C<aio_*> function creates a request. which is a C data structure not	115	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	116	directly visible to Perl.
…		…
168	use common::sense;	171	use common::sense;
169		172
170	use base 'Exporter';	173	use base 'Exporter';
171		174
172	BEGIN {	175	BEGIN {
173	our $VERSION = '4.15';	176	our $VERSION = 4.72;
174		177
175	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
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	179	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179	aio_pathsync aio_readahead aio_fiemap	182	aio_pathsync aio_readahead aio_fiemap aio_allocate
180	aio_rename aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs	187	aio_statvfs
		188	aio_slurp
185	aio_wd);	189	aio_wd);
186		190
187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	191	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	192	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189	min_parallel max_parallel max_idle idle_timeout	193	min_parallel max_parallel max_idle idle_timeout
190	nreqs nready npending nthreads	194	nreqs nready npending nthreads
191	max_poll_time max_poll_reqs	195	max_poll_time max_poll_reqs
192	sendfile fadvise madvise	196	sendfile fadvise madvise
193	mmap munmap munlock munlockall);	197	mmap munmap mremap munlock munlockall);
194		198
195	push @AIO_REQ, qw(aio_busy); # not exported	199	push @AIO_REQ, qw(aio_busy); # not exported
196		200
197	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	201	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
198		202
…		…
228	aio_unlink $pathname, $callback->($status)	232	aio_unlink $pathname, $callback->($status)
229	aio_mknod $pathname, $mode, $dev, $callback->($status)	233	aio_mknod $pathname, $mode, $dev, $callback->($status)
230	aio_link $srcpath, $dstpath, $callback->($status)	234	aio_link $srcpath, $dstpath, $callback->($status)
231	aio_symlink $srcpath, $dstpath, $callback->($status)	235	aio_symlink $srcpath, $dstpath, $callback->($status)
232	aio_readlink $pathname, $callback->($link)	236	aio_readlink $pathname, $callback->($link)
233	aio_realpath $pathname, $callback->($link)	237	aio_realpath $pathname, $callback->($path)
234	aio_rename $srcpath, $dstpath, $callback->($status)	238	aio_rename $srcpath, $dstpath, $callback->($status)
		239	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
235	aio_mkdir $pathname, $mode, $callback->($status)	240	aio_mkdir $pathname, $mode, $callback->($status)
236	aio_rmdir $pathname, $callback->($status)	241	aio_rmdir $pathname, $callback->($status)
237	aio_readdir $pathname, $callback->($entries)	242	aio_readdir $pathname, $callback->($entries)
238	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	243	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
239	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	244	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
…		…
241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	246	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242	aio_load $pathname, $data, $callback->($status)	247	aio_load $pathname, $data, $callback->($status)
243	aio_copy $srcpath, $dstpath, $callback->($status)	248	aio_copy $srcpath, $dstpath, $callback->($status)
244	aio_move $srcpath, $dstpath, $callback->($status)	249	aio_move $srcpath, $dstpath, $callback->($status)
245	aio_rmtree $pathname, $callback->($status)	250	aio_rmtree $pathname, $callback->($status)
		251	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		252	aio_ioctl $fh, $request, $buf, $callback->($status)
246	aio_sync $callback->($status)	253	aio_sync $callback->($status)
247	aio_syncfs $fh, $callback->($status)	254	aio_syncfs $fh, $callback->($status)
248	aio_fsync $fh, $callback->($status)	255	aio_fsync $fh, $callback->($status)
249	aio_fdatasync $fh, $callback->($status)	256	aio_fdatasync $fh, $callback->($status)
250	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	257	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
251	aio_pathsync $pathname, $callback->($status)	258	aio_pathsync $pathname, $callback->($status)
252	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
253	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	260	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
254	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	261	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
255	aio_mlockall $flags, $callback->($status)	262	aio_mlockall $flags, $callback->($status)
256	aio_group $callback->(...)	263	aio_group $callback->(...)
257	aio_nop $callback->()	264	aio_nop $callback->()
…		…
271	IO::AIO::idle_timeout $seconds	278	IO::AIO::idle_timeout $seconds
272	IO::AIO::max_outstanding $maxreqs	279	IO::AIO::max_outstanding $maxreqs
273	IO::AIO::nreqs	280	IO::AIO::nreqs
274	IO::AIO::nready	281	IO::AIO::nready
275	IO::AIO::npending	282	IO::AIO::npending
		283	IO::AIO::reinit
		284
		285	$nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
		286	IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
276		287
277	IO::AIO::sendfile $ofh, $ifh, $offset, $count	288	IO::AIO::sendfile $ofh, $ifh, $offset, $count
278	IO::AIO::fadvise $fh, $offset, $len, $advice	289	IO::AIO::fadvise $fh, $offset, $len, $advice
		290
279	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]	291	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280	IO::AIO::munmap $scalar	292	IO::AIO::munmap $scalar
		293	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
281	IO::AIO::madvise $scalar, $offset, $length, $advice	294	IO::AIO::madvise $scalar, $offset, $length, $advice
282	IO::AIO::mprotect $scalar, $offset, $length, $protect	295	IO::AIO::mprotect $scalar, $offset, $length, $protect
283	IO::AIO::munlock $scalar, $offset = 0, $length = undef	296	IO::AIO::munlock $scalar, $offset = 0, $length = undef
284	IO::AIO::munlockall	297	IO::AIO::munlockall
		298
		299	# stat extensions
		300	$counter = IO::AIO::st_gen
		301	$seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		302	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		303	$nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		304	$seconds = IO::AIO::st_btimesec
		305	($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		306
		307	# very much unportable syscalls
		308	IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		309	IO::AIO::tee $r_fh, $w_fh, $length, $flags
		310	$actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		311	($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		312	$fh = IO::AIO::memfd_create $pathname[, $flags]
		313	$fh = IO::AIO::eventfd [$initval, [$flags]]
		314	$fh = IO::AIO::timerfd_create $clockid[, $flags]
		315	($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		316	($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
285		317
286	=head2 API NOTES	318	=head2 API NOTES
287		319
288	All the C<aio_*> calls are more or less thin wrappers around the syscall	320	All the C<aio_*> calls are more or less thin wrappers around the syscall
289	with the same name (sans C<aio_>). The arguments are similar or identical,	321	with the same name (sans C<aio_>). The arguments are similar or identical,
…		…
362		394
363		395
364	=item aio_open $pathname, $flags, $mode, $callback->($fh)	396	=item aio_open $pathname, $flags, $mode, $callback->($fh)
365		397
366	Asynchronously open or create a file and call the callback with a newly	398	Asynchronously open or create a file and call the callback with a newly
367	created filehandle for the file.	399	created filehandle for the file (or C<undef> in case of an error).
368		400
369	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	401	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
370	for an explanation.	402	for an explanation.
371		403
372	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	404	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
395	following POSIX and non-POSIX constants are available (missing ones on	427	following POSIX and non-POSIX constants are available (missing ones on
396	your system are, as usual, C<0>):	428	your system are, as usual, C<0>):
397		429
398	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	430	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
399	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	431	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
400	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	432	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
401		433
402		434
403	=item aio_close $fh, $callback->($status)	435	=item aio_close $fh, $callback->($status)
404		436
405	Asynchronously close a file and call the callback with the result	437	Asynchronously close a file and call the callback with the result
…		…
440	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	472	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441		473
442	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	474	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443		475
444	Reads or writes C<$length> bytes from or to the specified C<$fh> and	476	Reads or writes C<$length> bytes from or to the specified C<$fh> and
445	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	477	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
446	and calls the callback without the actual number of bytes read (or -1 on	478	calls the callback with the actual number of bytes transferred (or -1 on
447	error, just like the syscall).	479	error, just like the syscall).
448		480
449	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	481	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450	offset plus the actual number of bytes read.	482	offset plus the actual number of bytes read.
451		483
…		…
509	As native sendfile syscalls (as practically any non-POSIX interface hacked	541	As native sendfile syscalls (as practically any non-POSIX interface hacked
510	together in a hurry to improve benchmark numbers) tend to be rather buggy	542	together in a hurry to improve benchmark numbers) tend to be rather buggy
511	on many systems, this implementation tries to work around some known bugs	543	on many systems, this implementation tries to work around some known bugs
512	in Linux and FreeBSD kernels (probably others, too), but that might fail,	544	in Linux and FreeBSD kernels (probably others, too), but that might fail,
513	so you really really should check the return value of C<aio_sendfile> -	545	so you really really should check the return value of C<aio_sendfile> -
514	fewre bytes than expected might have been transferred.	546	fewer bytes than expected might have been transferred.
515		547
516		548
517	=item aio_readahead $fh,$offset,$length, $callback->($retval)	549	=item aio_readahead $fh,$offset,$length, $callback->($retval)
518		550
519	C<aio_readahead> populates the page cache with data from a file so that	551	C<aio_readahead> populates the page cache with data from a file so that
…		…
523	whole pages, so that offset is effectively rounded down to a page boundary	555	whole pages, so that offset is effectively rounded down to a page boundary
524	and bytes are read up to the next page boundary greater than or equal to	556	and bytes are read up to the next page boundary greater than or equal to
525	(off-set+length). C<aio_readahead> does not read beyond the end of the	557	(off-set+length). C<aio_readahead> does not read beyond the end of the
526	file. The current file offset of the file is left unchanged.	558	file. The current file offset of the file is left unchanged.
527		559
528	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	560	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
529	emulated by simply reading the data, which would have a similar effect.	561	be emulated by simply reading the data, which would have a similar effect.
530		562
531		563
532	=item aio_stat $fh_or_path, $callback->($status)	564	=item aio_stat $fh_or_path, $callback->($status)
533		565
534	=item aio_lstat $fh, $callback->($status)	566	=item aio_lstat $fh, $callback->($status)
535		567
536	Works like perl's C<stat> or C<lstat> in void context. The callback will	568	Works almost exactly like perl's C<stat> or C<lstat> in void context. The
537	be called after the stat and the results will be available using C<stat _>	569	callback will be called after the stat and the results will be available
538	or C<-s _> etc...	570	using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
		571	and C<-T>).
539		572
540	The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,	573	The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
541	for an explanation.	574	for an explanation.
542		575
543	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	576	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
…		…
550	behaviour).	583	behaviour).
551		584
552	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,	585	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
553	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,	586	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
554	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.	587	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		588
		589	To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
		590	ACCESS>.
555		591
556	Example: Print the length of F</etc/passwd>:	592	Example: Print the length of F</etc/passwd>:
557		593
558	aio_stat "/etc/passwd", sub {	594	aio_stat "/etc/passwd", sub {
559	$_[0] and die "stat failed: $!";	595	$_[0] and die "stat failed: $!";
…		…
603	namemax => 255,	639	namemax => 255,
604	frsize => 1024,	640	frsize => 1024,
605	fsid => 1810	641	fsid => 1810
606	}	642	}
607		643
608
609	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	644	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
610		645
611	Works like perl's C<utime> function (including the special case of $atime	646	Works like perl's C<utime> function (including the special case of $atime
612	and $mtime being undef). Fractional times are supported if the underlying	647	and $mtime being undef). Fractional times are supported if the underlying
613	syscalls support them.	648	syscalls support them.
614		649
615	When called with a pathname, uses utimes(2) if available, otherwise	650	When called with a pathname, uses utimensat(2) or utimes(2) if available,
616	utime(2). If called on a file descriptor, uses futimes(2) if available,	651	otherwise utime(2). If called on a file descriptor, uses futimens(2)
617	otherwise returns ENOSYS, so this is not portable.	652	or futimes(2) if available, otherwise returns ENOSYS, so this is not
		653	portable.
618		654
619	Examples:	655	Examples:
620		656
621	# set atime and mtime to current time (basically touch(1)):	657	# set atime and mtime to current time (basically touch(1)):
622	aio_utime "path", undef, undef;	658	aio_utime "path", undef, undef;
…		…
642	Works like truncate(2) or ftruncate(2).	678	Works like truncate(2) or ftruncate(2).
643		679
644		680
645	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)	681	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
646		682
647	Allocates or freed disk space according to the C<$mode> argument. See the	683	Allocates or frees disk space according to the C<$mode> argument. See the
648	linux C<fallocate> docuemntation for details.	684	linux C<fallocate> documentation for details.
649		685
650	C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>	686	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
651	to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \|	687	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
652	IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.	688	to deallocate a file range.
		689
		690	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		691	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		692	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		693	to unshare shared blocks (see your L<fallocate(2)> manpage).
653		694
654	The file system block size used by C<fallocate> is presumably the	695	The file system block size used by C<fallocate> is presumably the
655	C<f_bsize> returned by C<statvfs>.	696	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		697	can dictate other limitations.
656		698
657	If C<fallocate> isn't available or cannot be emulated (currently no	699	If C<fallocate> isn't available or cannot be emulated (currently no
658	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.	700	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
659		701
660		702
…		…
702		744
703		745
704	=item aio_realpath $pathname, $callback->($path)	746	=item aio_realpath $pathname, $callback->($path)
705		747
706	Asynchronously make the path absolute and resolve any symlinks in	748	Asynchronously make the path absolute and resolve any symlinks in
707	C<$path>. The resulting path only consists of directories (Same as	749	C<$path>. The resulting path only consists of directories (same as
708	L<Cwd::realpath>).	750	L<Cwd::realpath>).
709		751
710	This request can be used to get the absolute path of the current working	752	This request can be used to get the absolute path of the current working
711	directory by passing it a path of F<.> (a single dot).	753	directory by passing it a path of F<.> (a single dot).
712		754
713		755
714	=item aio_rename $srcpath, $dstpath, $callback->($status)	756	=item aio_rename $srcpath, $dstpath, $callback->($status)
715		757
716	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	758	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
717	rename(2) and call the callback with the result code.	759	rename(2) and call the callback with the result code.
		760
		761	On systems that support the AIO::WD working directory abstraction
		762	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		763	of failing, C<rename> is called on the absolute path of C<$wd>.
		764
		765
		766	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		767
		768	Basically a version of C<aio_rename> with an additional C<$flags>
		769	argument. Calling this with C<$flags=0> is the same as calling
		770	C<aio_rename>.
		771
		772	Non-zero flags are currently only supported on GNU/Linux systems that
		773	support renameat2. Other systems fail with C<ENOSYS> in this case.
		774
		775	The following constants are available (missing ones are, as usual C<0>),
		776	see renameat2(2) for details:
		777
		778	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		779	and C<IO::AIO::RENAME_WHITEOUT>.
718		780
719		781
720	=item aio_mkdir $pathname, $mode, $callback->($status)	782	=item aio_mkdir $pathname, $mode, $callback->($status)
721		783
722	Asynchronously mkdir (create) a directory and call the callback with	784	Asynchronously mkdir (create) a directory and call the callback with
…		…
727	=item aio_rmdir $pathname, $callback->($status)	789	=item aio_rmdir $pathname, $callback->($status)
728		790
729	Asynchronously rmdir (delete) a directory and call the callback with the	791	Asynchronously rmdir (delete) a directory and call the callback with the
730	result code.	792	result code.
731		793
		794	On systems that support the AIO::WD working directory abstraction
		795	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		796	C<rmdir> is called on the absolute path of C<$wd>.
		797
732		798
733	=item aio_readdir $pathname, $callback->($entries)	799	=item aio_readdir $pathname, $callback->($entries)
734		800
735	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	801	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
736	directory (i.e. opendir + readdir + closedir). The entries will not be	802	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
751		817
752	=over 4	818	=over 4
753		819
754	=item IO::AIO::READDIR_DENTS	820	=item IO::AIO::READDIR_DENTS
755		821
756	When this flag is off, then the callback gets an arrayref consisting of	822	Normally the callback gets an arrayref consisting of names only (as
757	names only (as with C<aio_readdir>), otherwise it gets an arrayref with	823	with C<aio_readdir>). If this flag is set, then the callback gets an
758	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	824	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
759	entry in more detail.	825	single directory entry in more detail:
760		826
761	C<$name> is the name of the entry.	827	C<$name> is the name of the entry.
762		828
763	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	829	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
764		830
765	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	831	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
766	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	832	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
767	C<IO::AIO::DT_WHT>.	833	C<IO::AIO::DT_WHT>.
768		834
769	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	835	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
770	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	836	to know, you have to run stat yourself. Also, for speed/memory reasons,
771	scalars are read-only: you can not modify them.	837	the C<$type> scalars are read-only: you must not modify them.
772		838
773	C<$inode> is the inode number (which might not be exact on systems with 64	839	C<$inode> is the inode number (which might not be exact on systems with 64
774	bit inode numbers and 32 bit perls). This field has unspecified content on	840	bit inode numbers and 32 bit perls). This field has unspecified content on
775	systems that do not deliver the inode information.	841	systems that do not deliver the inode information.
776		842
…		…
787	short names are tried first.	853	short names are tried first.
788		854
789	=item IO::AIO::READDIR_STAT_ORDER	855	=item IO::AIO::READDIR_STAT_ORDER
790		856
791	When this flag is set, then the names will be returned in an order	857	When this flag is set, then the names will be returned in an order
792	suitable for stat()'ing each one. That is, when you plan to stat()	858	suitable for stat()'ing each one. That is, when you plan to stat() most or
793	all files in the given directory, then the returned order will likely	859	all files in the given directory, then the returned order will likely be
794	be fastest.	860	faster.
795		861
796	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	862	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
797	the likely dirs come first, resulting in a less optimal stat order.	863	then the likely dirs come first, resulting in a less optimal stat order
		864	for stat'ing all entries, but likely a more optimal order for finding
		865	subdirectories.
798		866
799	=item IO::AIO::READDIR_FOUND_UNKNOWN	867	=item IO::AIO::READDIR_FOUND_UNKNOWN
800		868
801	This flag should not be set when calling C<aio_readdirx>. Instead, it	869	This flag should not be set when calling C<aio_readdirx>. Instead, it
802	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	870	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
804	C<$type>'s are known, which can be used to speed up some algorithms.	872	C<$type>'s are known, which can be used to speed up some algorithms.
805		873
806	=back	874	=back
807		875
808		876
		877	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		878
		879	Opens, reads and closes the given file. The data is put into C<$data>,
		880	which is resized as required.
		881
		882	If C<$offset> is negative, then it is counted from the end of the file.
		883
		884	If C<$length> is zero, then the remaining length of the file is
		885	used. Also, in this case, the same limitations to modifying C<$data> apply
		886	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		887	with C<substr>. If the size of the file is known, specifying a non-zero
		888	C<$length> results in a performance advantage.
		889
		890	This request is similar to the older C<aio_load> request, but since it is
		891	a single request, it might be more efficient to use.
		892
		893	Example: load F</etc/passwd> into C<$passwd>.
		894
		895	my $passwd;
		896	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		897	$_[0] >= 0
		898	or die "/etc/passwd: $!\n";
		899
		900	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		901	print $passwd;
		902	};
		903	IO::AIO::flush;
		904
		905
809	=item aio_load $pathname, $data, $callback->($status)	906	=item aio_load $pathname, $data, $callback->($status)
810		907
811	This is a composite request that tries to fully load the given file into	908	This is a composite request that tries to fully load the given file into
812	memory. Status is the same as with aio_read.	909	memory. Status is the same as with aio_read.
		910
		911	Using C<aio_slurp> might be more efficient, as it is a single request.
813		912
814	=cut	913	=cut
815		914
816	sub aio_load($$;$) {	915	sub aio_load($$;$) {
817	my ($path, undef, $cb) = @_;	916	my ($path, undef, $cb) = @_;
…		…
837	=item aio_copy $srcpath, $dstpath, $callback->($status)	936	=item aio_copy $srcpath, $dstpath, $callback->($status)
838		937
839	Try to copy the I<file> (directories not supported as either source or	938	Try to copy the I<file> (directories not supported as either source or
840	destination) from C<$srcpath> to C<$dstpath> and call the callback with	939	destination) from C<$srcpath> to C<$dstpath> and call the callback with
841	a status of C<0> (ok) or C<-1> (error, see C<$!>).	940	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		941
		942	Existing destination files will be truncated.
842		943
843	This is a composite request that creates the destination file with	944	This is a composite request that creates the destination file with
844	mode 0200 and copies the contents of the source file into it using	945	mode 0200 and copies the contents of the source file into it using
845	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	946	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
846	uid/gid, in that order.	947	uid/gid, in that order.
…		…
956	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1057	Scans a directory (similar to C<aio_readdir>) but additionally tries to
957	efficiently separate the entries of directory C<$path> into two sets of	1058	efficiently separate the entries of directory C<$path> into two sets of
958	names, directories you can recurse into (directories), and ones you cannot	1059	names, directories you can recurse into (directories), and ones you cannot
959	recurse into (everything else, including symlinks to directories).	1060	recurse into (everything else, including symlinks to directories).
960		1061
961	C<aio_scandir> is a composite request that creates of many sub requests_	1062	C<aio_scandir> is a composite request that generates many sub requests.
962	C<$maxreq> specifies the maximum number of outstanding aio requests that	1063	C<$maxreq> specifies the maximum number of outstanding aio requests that
963	this function generates. If it is C<< <= 0 >>, then a suitable default	1064	this function generates. If it is C<< <= 0 >>, then a suitable default
964	will be chosen (currently 4).	1065	will be chosen (currently 4).
965		1066
966	On error, the callback is called without arguments, otherwise it receives	1067	On error, the callback is called without arguments, otherwise it receives
…		…
1030	aioreq_pri $pri;	1131	aioreq_pri $pri;
1031	add $grp aio_stat $wd, sub {	1132	add $grp aio_stat $wd, sub {
1032	return $grp->result () if $_[0];	1133	return $grp->result () if $_[0];
1033	my $now = time;	1134	my $now = time;
1034	my $hash1 = join ":", (stat _)[0,1,3,7,9];	1135	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		1136	my $rdxflags = READDIR_DIRS_FIRST;
		1137
		1138	if ((stat _)[3] < 2) {
		1139	# at least one non-POSIX filesystem exists
		1140	# that returns useful DT_type values: btrfs,
		1141	# so optimise for this here by requesting dents
		1142	$rdxflags \|= READDIR_DENTS;
		1143	}
1035		1144
1036	# read the directory entries	1145	# read the directory entries
1037	aioreq_pri $pri;	1146	aioreq_pri $pri;
1038	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {	1147	add $grp aio_readdirx $wd, $rdxflags, sub {
1039	my $entries = shift	1148	my ($entries, $flags) = @_
1040	or return $grp->result ();	1149	or return $grp->result ();
		1150
		1151	if ($rdxflags & READDIR_DENTS) {
		1152	# if we requested type values, see if we can use them directly.
		1153
		1154	# if there were any DT_UNKNOWN entries then we assume we
		1155	# don't know. alternatively, we could assume that if we get
		1156	# one DT_DIR, then all directories are indeed marked with
		1157	# DT_DIR, but this seems not required for btrfs, and this
		1158	# is basically the "btrfs can't get it's act together" code
		1159	# branch.
		1160	unless ($flags & READDIR_FOUND_UNKNOWN) {
		1161	# now we have valid DT_ information for all entries,
		1162	# so use it as an optimisation without further stat's.
		1163	# they must also all be at the beginning of @$entries
		1164	# by now.
		1165
		1166	my $dirs;
		1167
		1168	if (@$entries) {
		1169	for (0 .. $#$entries) {
		1170	if ($entries->[$_][1] != DT_DIR) {
		1171	# splice out directories
		1172	$dirs = [splice @$entries, 0, $_];
		1173	last;
		1174	}
		1175	}
		1176
		1177	# if we didn't find any non-dir, then all entries are dirs
		1178	unless ($dirs) {
		1179	($dirs, $entries) = ($entries, []);
		1180	}
		1181	} else {
		1182	# directory is empty, so there are no sbdirs
		1183	$dirs = [];
		1184	}
		1185
		1186	# either splice'd the directories out or the dir was empty.
		1187	# convert dents to filenames
		1188	$_ = $_->[0] for @$dirs;
		1189	$_ = $_->[0] for @$entries;
		1190
		1191	return $grp->result ($dirs, $entries);
		1192	}
		1193
		1194	# cannot use, so return to our old ways
		1195	# by pretending we only scanned for names.
		1196	$_ = $_->[0] for @$entries;
		1197	}
1041		1198
1042	# stat the dir another time	1199	# stat the dir another time
1043	aioreq_pri $pri;	1200	aioreq_pri $pri;
1044	add $grp aio_stat $wd, sub {	1201	add $grp aio_stat $wd, sub {
1045	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1202	my $hash2 = join ":", (stat _)[0,1,3,7,9];
…		…
1100	}	1257	}
1101		1258
1102	=item aio_rmtree $pathname, $callback->($status)	1259	=item aio_rmtree $pathname, $callback->($status)
1103		1260
1104	Delete a directory tree starting (and including) C<$path>, return the	1261	Delete a directory tree starting (and including) C<$path>, return the
1105	status of the final C<rmdir> only. This is a composite request that	1262	status of the final C<rmdir> only. This is a composite request that
1106	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1263	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1107	everything else.	1264	everything else.
1108		1265
1109	=cut	1266	=cut
1110		1267
…		…
1131	add $grp $dirgrp;	1288	add $grp $dirgrp;
1132	};	1289	};
1133		1290
1134	$grp	1291	$grp
1135	}	1292	}
		1293
		1294	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1295
		1296	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1297
		1298	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1299	they execute asynchronously and pass the return value to the callback.
		1300
		1301	Both calls can be used for a lot of things, some of which make more sense
		1302	to run asynchronously in their own thread, while some others make less
		1303	sense. For example, calls that block waiting for external events, such
		1304	as locking, will also lock down an I/O thread while it is waiting, which
		1305	can deadlock the whole I/O system. At the same time, there might be no
		1306	alternative to using a thread to wait.
		1307
		1308	So in general, you should only use these calls for things that do
		1309	(filesystem) I/O, not for things that wait for other events (network,
		1310	other processes), although if you are careful and know what you are doing,
		1311	you still can.
		1312
		1313	The following constants are available (missing ones are, as usual C<0>):
		1314
		1315	C<F_DUPFD_CLOEXEC>,
		1316
		1317	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1318
		1319	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1320
		1321	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1322	C<FS_IOC_FIEMAP>.
		1323
		1324	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1325	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1326
		1327	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1328	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1329	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1330	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1331	C<FS_FL_USER_MODIFIABLE>.
		1332
		1333	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1334	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1335	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1336	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1136		1337
1137	=item aio_sync $callback->($status)	1338	=item aio_sync $callback->($status)
1138		1339
1139	Asynchronously call sync and call the callback when finished.	1340	Asynchronously call sync and call the callback when finished.
1140		1341
…		…
1209	};	1410	};
1210		1411
1211	$grp	1412	$grp
1212	}	1413	}
1213		1414
1214	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1415	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1215		1416
1216	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1417	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1217	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1418	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1218	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1419	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1219	scalar must only be modified in-place while an aio operation is pending on	1420	scalar must only be modified in-place while an aio operation is pending on
…		…
1221		1422
1222	It calls the C<msync> function of your OS, if available, with the memory	1423	It calls the C<msync> function of your OS, if available, with the memory
1223	area starting at C<$offset> in the string and ending C<$length> bytes	1424	area starting at C<$offset> in the string and ending C<$length> bytes
1224	later. If C<$length> is negative, counts from the end, and if C<$length>	1425	later. If C<$length> is negative, counts from the end, and if C<$length>
1225	is C<undef>, then it goes till the end of the string. The flags can be	1426	is C<undef>, then it goes till the end of the string. The flags can be
1226	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1427	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1227	C<IO::AIO::MS_SYNC>.	1428	C<IO::AIO::MS_INVALIDATE>.
1228		1429
1229	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1430	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1230		1431
1231	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1432	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1232	scalars.	1433	scalars.
1233		1434
1234	It touches (reads or writes) all memory pages in the specified	1435	It touches (reads or writes) all memory pages in the specified
1235	range inside the scalar. All caveats and parameters are the same	1436	range inside the scalar. All caveats and parameters are the same
1236	as for C<aio_msync>, above, except for flags, which must be either	1437	as for C<aio_msync>, above, except for flags, which must be either
1237	C<0> (which reads all pages and ensures they are instantiated) or	1438	C<0> (which reads all pages and ensures they are instantiated) or
1238	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1439	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1239	writing an octet from it, which dirties the page).	1440	writing an octet from it, which dirties the page).
1240		1441
1241	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1442	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1242		1443
1243	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1444	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1262	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;	1463	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1263	aio_mlock $data; # mlock in background	1464	aio_mlock $data; # mlock in background
1264		1465
1265	=item aio_mlockall $flags, $callback->($status)	1466	=item aio_mlockall $flags, $callback->($status)
1266		1467
1267	Calls the C<mlockall> function with the given C<$flags> (a combination of	1468	Calls the C<mlockall> function with the given C<$flags> (a
1268	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).	1469	combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
		1470	C<IO::AIO::MCL_ONFAULT>).
1269		1471
1270	On systems that do not implement C<mlockall>, this function returns C<-1>	1472	On systems that do not implement C<mlockall>, this function returns C<-1>
1271	and sets errno to C<ENOSYS>.	1473	and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
		1474	by the system result in a return value of C<-1> with errno being set to
		1475	C<EINVAL>.
1272		1476
1273	Note that the corresponding C<munlockall> is synchronous and is	1477	Note that the corresponding C<munlockall> is synchronous and is
1274	documented under L<MISCELLANEOUS FUNCTIONS>.	1478	documented under L<MISCELLANEOUS FUNCTIONS>.
1275		1479
1276	Example: asynchronously lock all current and future pages into memory.	1480	Example: asynchronously lock all current and future pages into memory.
1277		1481
1278	aio_mlockall IO::AIO::MCL_FUTURE;	1482	aio_mlockall IO::AIO::MCL_FUTURE;
1279		1483
1280	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)	1484	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1281		1485
1282	Queries the extents of the given file (by calling the Linux FIEMAP ioctl,	1486	Queries the extents of the given file (by calling the Linux C<FIEMAP>
1283	see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the	1487	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1284	C<ioctl> is not available on your OS, then this request will fail with	1488	the ioctl is not available on your OS, then this request will fail with
1285	C<ENOSYS>.	1489	C<ENOSYS>.
1286		1490
1287	C<$start> is the starting offset to query extents for, C<$length> is the	1491	C<$start> is the starting offset to query extents for, C<$length> is the
1288	size of the range to query - if it is C<undef>, then the whole file will	1492	size of the range to query - if it is C<undef>, then the whole file will
1289	be queried.	1493	be queried.
…		…
1292	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also	1496	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1293	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query	1497	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1294	the data portion.	1498	the data portion.
1295		1499
1296	C<$count> is the maximum number of extent records to return. If it is	1500	C<$count> is the maximum number of extent records to return. If it is
1297	C<undef>, then IO::AIO queries all extents of the file. As a very special	1501	C<undef>, then IO::AIO queries all extents of the range. As a very special
1298	case, if it is C<0>, then the callback receives the number of extents	1502	case, if it is C<0>, then the callback receives the number of extents
1299	instead of the extents themselves.	1503	instead of the extents themselves (which is unreliable, see below).
1300		1504
1301	If an error occurs, the callback receives no arguments. The special	1505	If an error occurs, the callback receives no arguments. The special
1302	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.	1506	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1303		1507
1304	Otherwise, the callback receives an array reference with extent	1508	Otherwise, the callback receives an array reference with extent
…		…
1306	following members:	1510	following members:
1307		1511
1308	[$logical, $physical, $length, $flags]	1512	[$logical, $physical, $length, $flags]
1309		1513
1310	Flags is any combination of the following flag values (typically either C<0>	1514	Flags is any combination of the following flag values (typically either C<0>
1311	or C<IO::AIO::FIEMAP_EXTENT_LAST>):	1515	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1312		1516
1313	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,	1517	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1314	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,	1518	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1315	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,	1519	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1316	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,	1520	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1317	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or	1521	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1318	C<IO::AIO::FIEMAP_EXTENT_SHARED>.	1522	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1319		1523
		1524	At the time of this writing (Linux 3.2), this request is unreliable unless
		1525	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1526	it to return all extents of a range for files with a large number of
		1527	extents. The code (only) works around all these issues if C<$count> is
		1528	C<undef>.
		1529
1320	=item aio_group $callback->(...)	1530	=item aio_group $callback->(...)
1321		1531
1322	This is a very special aio request: Instead of doing something, it is a	1532	This is a very special aio request: Instead of doing something, it is a
1323	container for other aio requests, which is useful if you want to bundle	1533	container for other aio requests, which is useful if you want to bundle
1324	many requests into a single, composite, request with a definite callback	1534	many requests into a single, composite, request with a definite callback
…		…
1407	aio_stat [$etcdir, "passwd"], sub {	1617	aio_stat [$etcdir, "passwd"], sub {
1408	# yay	1618	# yay
1409	};	1619	};
1410	};	1620	};
1411		1621
1412	That C<aio_wd> is a request and not a normal function shows that creating	1622	The fact that C<aio_wd> is a request and not a normal function shows that
1413	an IO::AIO::WD object is itself a potentially blocking operation, which is	1623	creating an IO::AIO::WD object is itself a potentially blocking operation,
1414	why it is done asynchronously.	1624	which is why it is done asynchronously.
1415		1625
1416	To stat the directory obtained with C<aio_wd> above, one could write	1626	To stat the directory obtained with C<aio_wd> above, one could write
1417	either of the following three request calls:	1627	either of the following three request calls:
1418		1628
1419	aio_lstat "/etc" , sub { ... # pathname as normal string	1629	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1436	There are some caveats: when directories get renamed (or deleted), the	1646	There are some caveats: when directories get renamed (or deleted), the
1437	pathname string doesn't change, so will point to the new directory (or	1647	pathname string doesn't change, so will point to the new directory (or
1438	nowhere at all), while the directory fd, if available on the system,	1648	nowhere at all), while the directory fd, if available on the system,
1439	will still point to the original directory. Most functions accepting a	1649	will still point to the original directory. Most functions accepting a
1440	pathname will use the directory fd on newer systems, and the string on	1650	pathname will use the directory fd on newer systems, and the string on
1441	older systems. Some functions (such as realpath) will always rely on the	1651	older systems. Some functions (such as C<aio_realpath>) will always rely on
1442	string form of the pathname.	1652	the string form of the pathname.
1443		1653
1444	So this fucntionality is mainly useful to get some protection against	1654	So this functionality is mainly useful to get some protection against
1445	C<chdir>, to easily get an absolute path out of a relative path for future	1655	C<chdir>, to easily get an absolute path out of a relative path for future
1446	reference, and to speed up doing many operations in the same directory	1656	reference, and to speed up doing many operations in the same directory
1447	(e.g. when stat'ing all files in a directory).	1657	(e.g. when stat'ing all files in a directory).
1448		1658
1449	The following functions implement this working directory abstraction:	1659	The following functions implement this working directory abstraction:
…		…
1462	passing C<undef> as working directory component of a pathname fails the	1672	passing C<undef> as working directory component of a pathname fails the
1463	request with C<ENOENT>, there is often no need for error checking in the	1673	request with C<ENOENT>, there is often no need for error checking in the
1464	C<aio_wd> callback, as future requests using the value will fail in the	1674	C<aio_wd> callback, as future requests using the value will fail in the
1465	expected way.	1675	expected way.
1466		1676
1467	If this call isn't available because your OS lacks it or it couldn't be
1468	detected, it will be emulated by calling C<fsync> instead.
1469
1470	=item IO::AIO::CWD	1677	=item IO::AIO::CWD
1471		1678
1472	This is a compiletime constant (object) that represents the process	1679	This is a compiletime constant (object) that represents the process
1473	current working directory.	1680	current working directory.
1474		1681
1475	Specifying this object as working directory object for a pathname is as	1682	Specifying this object as working directory object for a pathname is as if
1476	if the pathname would be specified directly, without a directory object,	1683	the pathname would be specified directly, without a directory object. For
1477	e.g., these calls are functionally identical:	1684	example, these calls are functionally identical:
1478		1685
1479	aio_stat "somefile", sub { ... };	1686	aio_stat "somefile", sub { ... };
1480	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1687	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1481		1688
1482	=back	1689	=back
1483		1690
		1691	To recover the path associated with an IO::AIO::WD object, you can use
		1692	C<aio_realpath>:
		1693
		1694	aio_realpath $wd, sub {
		1695	warn "path is $_[0]\n";
		1696	};
		1697
		1698	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1699	sometimes, fall back to using an absolue path.
1484		1700
1485	=head2 IO::AIO::REQ CLASS	1701	=head2 IO::AIO::REQ CLASS
1486		1702
1487	All non-aggregate C<aio_*> functions return an object of this class when	1703	All non-aggregate C<aio_*> functions return an object of this class when
1488	called in non-void context.	1704	called in non-void context.
…		…
1649	The default value for the limit is C<0>, but note that setting a feeder	1865	The default value for the limit is C<0>, but note that setting a feeder
1650	automatically bumps it up to C<2>.	1866	automatically bumps it up to C<2>.
1651		1867
1652	=back	1868	=back
1653		1869
		1870
1654	=head2 SUPPORT FUNCTIONS	1871	=head2 SUPPORT FUNCTIONS
1655		1872
1656	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1873	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1657		1874
1658	=over 4	1875	=over 4
…		…
1666		1883
1667	See C<poll_cb> for an example.	1884	See C<poll_cb> for an example.
1668		1885
1669	=item IO::AIO::poll_cb	1886	=item IO::AIO::poll_cb
1670		1887
1671	Process some outstanding events on the result pipe. You have to call	1888	Process some requests that have reached the result phase (i.e. they have
		1889	been executed but the results are not yet reported). You have to call
		1890	this "regularly" to finish outstanding requests.
		1891
1672	this regularly. Returns C<0> if all events could be processed (or there	1892	Returns C<0> if all events could be processed (or there were no
1673	were no events to process), or C<-1> if it returned earlier for whatever	1893	events to process), or C<-1> if it returned earlier for whatever
1674	reason. Returns immediately when no events are outstanding. The amount of	1894	reason. Returns immediately when no events are outstanding. The amount
1675	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1895	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1676	C<IO::AIO::max_poll_time>.	1896	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1677		1897
1678	If not all requests were processed for whatever reason, the filehandle	1898	If not all requests were processed for whatever reason, the poll file
1679	will still be ready when C<poll_cb> returns, so normally you don't have to	1899	descriptor will still be ready when C<poll_cb> returns, so normally you
1680	do anything special to have it called later.	1900	don't have to do anything special to have it called later.
1681		1901
1682	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1902	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1683	ready, it can be beneficial to call this function from loops which submit	1903	ready, it can be beneficial to call this function from loops which submit
1684	a lot of requests, to make sure the results get processed when they become	1904	a lot of requests, to make sure the results get processed when they become
1685	available and not just when the loop is finished and the event loop takes	1905	available and not just when the loop is finished and the event loop takes
…		…
1694	poll => 'r', async => 1,	1914	poll => 'r', async => 1,
1695	cb => \&IO::AIO::poll_cb);	1915	cb => \&IO::AIO::poll_cb);
1696		1916
1697	=item IO::AIO::poll_wait	1917	=item IO::AIO::poll_wait
1698		1918
1699	If there are any outstanding requests and none of them in the result	1919	Wait until either at least one request is in the result phase or no
1700	phase, wait till the result filehandle becomes ready for reading (simply	1920	requests are outstanding anymore.
1701	does a C<select> on the filehandle. This is useful if you want to	1921
1702	synchronously wait for some requests to finish).	1922	This is useful if you want to synchronously wait for some requests to
		1923	become ready, without actually handling them.
1703		1924
1704	See C<nreqs> for an example.	1925	See C<nreqs> for an example.
1705		1926
1706	=item IO::AIO::poll	1927	=item IO::AIO::poll
1707		1928
…		…
1718		1939
1719	Strictly equivalent to:	1940	Strictly equivalent to:
1720		1941
1721	IO::AIO::poll_wait, IO::AIO::poll_cb	1942	IO::AIO::poll_wait, IO::AIO::poll_cb
1722	while IO::AIO::nreqs;	1943	while IO::AIO::nreqs;
		1944
		1945	This function can be useful at program aborts, to make sure outstanding
		1946	I/O has been done (C<IO::AIO> uses an C<END> block which already calls
		1947	this function on normal exits), or when you are merely using C<IO::AIO>
		1948	for its more advanced functions, rather than for async I/O, e.g.:
		1949
		1950	my ($dirs, $nondirs);
		1951	IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
		1952	IO::AIO::flush;
		1953	# $dirs, $nondirs are now set
1723		1954
1724	=item IO::AIO::max_poll_reqs $nreqs	1955	=item IO::AIO::max_poll_reqs $nreqs
1725		1956
1726	=item IO::AIO::max_poll_time $seconds	1957	=item IO::AIO::max_poll_time $seconds
1727		1958
…		…
1754	poll => 'r', nice => 1,	1985	poll => 'r', nice => 1,
1755	cb => &IO::AIO::poll_cb);	1986	cb => &IO::AIO::poll_cb);
1756		1987
1757	=back	1988	=back
1758		1989
		1990
1759	=head3 CONTROLLING THE NUMBER OF THREADS	1991	=head3 CONTROLLING THE NUMBER OF THREADS
1760		1992
1761	=over	1993	=over
1762		1994
1763	=item IO::AIO::min_parallel $nthreads	1995	=item IO::AIO::min_parallel $nthreads
…		…
1828		2060
1829	This is a very bad function to use in interactive programs because it	2061	This is a very bad function to use in interactive programs because it
1830	blocks, and a bad way to reduce concurrency because it is inexact: Better	2062	blocks, and a bad way to reduce concurrency because it is inexact: Better
1831	use an C<aio_group> together with a feed callback.	2063	use an C<aio_group> together with a feed callback.
1832		2064
1833	It's main use is in scripts without an event loop - when you want to stat	2065	Its main use is in scripts without an event loop - when you want to stat
1834	a lot of files, you can write somehting like this:	2066	a lot of files, you can write something like this:
1835		2067
1836	IO::AIO::max_outstanding 32;	2068	IO::AIO::max_outstanding 32;
1837		2069
1838	for my $path (...) {	2070	for my $path (...) {
1839	aio_stat $path , ...;	2071	aio_stat $path , ...;
…		…
1850	The default value for C<max_outstanding> is very large, so there is no	2082	The default value for C<max_outstanding> is very large, so there is no
1851	practical limit on the number of outstanding requests.	2083	practical limit on the number of outstanding requests.
1852		2084
1853	=back	2085	=back
1854		2086
		2087
1855	=head3 STATISTICAL INFORMATION	2088	=head3 STATISTICAL INFORMATION
1856		2089
1857	=over	2090	=over
1858		2091
1859	=item IO::AIO::nreqs	2092	=item IO::AIO::nreqs
…		…
1876	Returns the number of requests currently in the pending state (executed,	2109	Returns the number of requests currently in the pending state (executed,
1877	but not yet processed by poll_cb).	2110	but not yet processed by poll_cb).
1878		2111
1879	=back	2112	=back
1880		2113
		2114
		2115	=head3 SUBSECOND STAT TIME ACCESS
		2116
		2117	Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
		2118	generally find access/modification and change times with subsecond time
		2119	accuracy of the system supports it, but perl's built-in functions only
		2120	return the integer part.
		2121
		2122	The following functions return the timestamps of the most recent
		2123	stat with subsecond precision on most systems and work both after
		2124	C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
		2125	value is only meaningful after a successful C<stat>/C<lstat> call, or
		2126	during/after a successful C<aio_stat>/C<aio_lstat> callback.
		2127
		2128	This is similar to the L<Time::HiRes> C<stat> functions, but can return
		2129	full resolution without rounding and work with standard perl C<stat>,
		2130	alleviating the need to call the special C<Time::HiRes> functions, which
		2131	do not act like their perl counterparts.
		2132
		2133	On operating systems or file systems where subsecond time resolution is
		2134	not supported or could not be detected, a fractional part of C<0> is
		2135	returned, so it is always safe to call these functions.
		2136
		2137	=over 4
		2138
		2139	=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		2140
		2141	Return the access, modication, change or birth time, respectively,
		2142	including fractional part. Due to the limited precision of floating point,
		2143	the accuracy on most platforms is only a bit better than milliseconds
		2144	for times around now - see the I<nsec> function family, below, for full
		2145	accuracy.
		2146
		2147	File birth time is only available when the OS and perl support it (on
		2148	FreeBSD and NetBSD at the time of this writing, although support is
		2149	adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
		2150	it). On systems where it isn't available, C<0> is currently returned, but
		2151	this might change to C<undef> in a future version.
		2152
		2153	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		2154
		2155	Returns access, modification, change and birth time all in one go, and
		2156	maybe more times in the future version.
		2157
		2158	=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		2159
		2160	Return the fractional access, modifcation, change or birth time, in nanoseconds,
		2161	as an integer in the range C<0> to C<999999999>.
		2162
		2163	Note that no accessors are provided for access, modification and
		2164	change times - you need to get those from C<stat _> if required (C<int
		2165	IO::AIO::st_atime> and so on will I<not> generally give you the correct
		2166	value).
		2167
		2168	=item $seconds = IO::AIO::st_btimesec
		2169
		2170	The (integral) seconds part of the file birth time, if available.
		2171
		2172	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		2173
		2174	Like the functions above, but returns all four times in one go (and maybe
		2175	more in future versions).
		2176
		2177	=item $counter = IO::AIO::st_gen
		2178
		2179	Returns the generation counter (in practice this is just a random number)
		2180	of the file. This is only available on platforms which have this member in
		2181	their C<struct stat> (most BSDs at the time of this writing) and generally
		2182	only to the root usert. If unsupported, C<0> is returned, but this might
		2183	change to C<undef> in a future version.
		2184
		2185	=back
		2186
		2187	Example: print the high resolution modification time of F</etc>, using
		2188	C<stat>, and C<IO::AIO::aio_stat>.
		2189
		2190	if (stat "/etc") {
		2191	printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
		2192	}
		2193
		2194	IO::AIO::aio_stat "/etc", sub {
		2195	$_[0]
		2196	and return;
		2197
		2198	printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
		2199	};
		2200
		2201	IO::AIO::flush;
		2202
		2203	Output of the awbove on my system, showing reduced and full accuracy:
		2204
		2205	stat(/etc) mtime: 1534043702.020808
		2206	aio_stat(/etc) mtime: 1534043702.020807792
		2207
		2208
1881	=head3 MISCELLANEOUS FUNCTIONS	2209	=head3 MISCELLANEOUS FUNCTIONS
1882		2210
1883	IO::AIO implements some functions that might be useful, but are not	2211	IO::AIO implements some functions that are useful when you want to use
1884	asynchronous.	2212	some "Advanced I/O" function not available to in Perl, without going the
		2213	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2214	counterpart.
1885		2215
1886	=over 4	2216	=over 4
		2217
		2218	=item $numfd = IO::AIO::get_fdlimit
		2219
		2220	This function is I<EXPERIMENTAL> and subject to change.
		2221
		2222	Tries to find the current file descriptor limit and returns it, or
		2223	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2224	the highest valid file descriptor number.
		2225
		2226	=item IO::AIO::min_fdlimit [$numfd]
		2227
		2228	This function is I<EXPERIMENTAL> and subject to change.
		2229
		2230	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2231	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2232	is missing, it will try to set a very high limit, although this is not
		2233	recommended when you know the actual minimum that you require.
		2234
		2235	If the limit cannot be raised enough, the function makes a best-effort
		2236	attempt to increase the limit as much as possible, using various
		2237	tricks, while still failing. You can query the resulting limit using
		2238	C<IO::AIO::get_fdlimit>.
		2239
		2240	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2241	true.
1887		2242
1888	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2243	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1889		2244
1890	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2245	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1891	but is blocking (this makes most sense if you know the input data is	2246	but is blocking (this makes most sense if you know the input data is
…		…
1908	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2263	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1909		2264
1910	Simply calls the C<posix_madvise> function (see its	2265	Simply calls the C<posix_madvise> function (see its
1911	manpage for details). The following advice constants are	2266	manpage for details). The following advice constants are
1912	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2267	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1913	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2268	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2269	C<IO::AIO::MADV_DONTNEED>.
		2270
		2271	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2272	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2273	will be reduced to fit into the C<$scalar>.
1914		2274
1915	On systems that do not implement C<posix_madvise>, this function returns	2275	On systems that do not implement C<posix_madvise>, this function returns
1916	ENOSYS, otherwise the return value of C<posix_madvise>.	2276	ENOSYS, otherwise the return value of C<posix_madvise>.
1917		2277
1918	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2278	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1920	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2280	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1921	$scalar (see its manpage for details). The following protect	2281	$scalar (see its manpage for details). The following protect
1922	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2282	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1923	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2283	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1924		2284
		2285	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2286	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2287	will be reduced to fit into the C<$scalar>.
		2288
1925	On systems that do not implement C<mprotect>, this function returns	2289	On systems that do not implement C<mprotect>, this function returns
1926	ENOSYS, otherwise the return value of C<mprotect>.	2290	ENOSYS, otherwise the return value of C<mprotect>.
1927		2291
1928	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2292	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1929		2293
1930	Memory-maps a file (or anonymous memory range) and attaches it to the	2294	Memory-maps a file (or anonymous memory range) and attaches it to the
1931	given C<$scalar>, which will act like a string scalar. Returns true on	2295	given C<$scalar>, which will act like a string scalar. Returns true on
1932	success, and false otherwise.	2296	success, and false otherwise.
1933		2297
		2298	The scalar must exist, but its contents do not matter - this means you
		2299	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2300	the scalar first.
		2301
1934	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2302	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1935	change the string length, and most read-only operations such as copying it	2303	which don't change the string length, and most read-only operations such
1936	or searching it with regexes and so on.	2304	as copying it or searching it with regexes and so on.
1937		2305
1938	Anything else is unsafe and will, at best, result in memory leaks.	2306	Anything else is unsafe and will, at best, result in memory leaks.
1939		2307
1940	The memory map associated with the C<$scalar> is automatically removed	2308	The memory map associated with the C<$scalar> is automatically removed
1941	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2309	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1942	C<IO::AIO::munmap> functions are called.	2310	or C<IO::AIO::munmap> functions are called on it.
1943		2311
1944	This calls the C<mmap>(2) function internally. See your system's manual	2312	This calls the C<mmap>(2) function internally. See your system's manual
1945	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2313	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1946		2314
1947	The C<$length> must be larger than zero and smaller than the actual	2315	The C<$length> must be larger than zero and smaller than the actual
1948	filesize.	2316	filesize.
1949		2317
1950	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2318	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1951	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2319	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1952		2320
1953	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2321	C<$flags> can be a combination of
1954	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2322	C<IO::AIO::MAP_SHARED> or
1955	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2323	C<IO::AIO::MAP_PRIVATE>,
		2324	or a number of system-specific flags (when not available, the are C<0>):
1956	(which is set to C<MAP_ANON> if your system only provides this	2325	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1957	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2326	C<IO::AIO::MAP_LOCKED>,
1958	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2327	C<IO::AIO::MAP_NORESERVE>,
		2328	C<IO::AIO::MAP_POPULATE>,
1959	C<IO::AIO::MAP_NONBLOCK>	2329	C<IO::AIO::MAP_NONBLOCK>,
		2330	C<IO::AIO::MAP_FIXED>,
		2331	C<IO::AIO::MAP_GROWSDOWN>,
		2332	C<IO::AIO::MAP_32BIT>,
		2333	C<IO::AIO::MAP_HUGETLB> or
		2334	C<IO::AIO::MAP_STACK>.
1960		2335
1961	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2336	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1962		2337
1963	C<$offset> is the offset from the start of the file - it generally must be	2338	C<$offset> is the offset from the start of the file - it generally must be
1964	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2339	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1977	my $fast_md5 = md5 $data;	2352	my $fast_md5 = md5 $data;
1978		2353
1979	=item IO::AIO::munmap $scalar	2354	=item IO::AIO::munmap $scalar
1980		2355
1981	Removes a previous mmap and undefines the C<$scalar>.	2356	Removes a previous mmap and undefines the C<$scalar>.
		2357
		2358	=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
		2359
		2360	Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
		2361	been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
		2362	C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
		2363
		2364	Returns true if successful, and false otherwise. If the underlying mmapped
		2365	region has changed address, then the true value has the numerical value
		2366	C<1>, otherwise it has the numerical value C<0>:
		2367
		2368	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		2369	or die "mremap: $!";
		2370
		2371	if ($success*1) {
		2372	warn "scalar has chanegd address in memory\n";
		2373	}
		2374
		2375	C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
		2376	implemented, but not supported and might go away in a future version.
		2377
		2378	On systems where this call is not supported or is not emulated, this call
		2379	returns falls and sets C<$!> to C<ENOSYS>.
		2380
		2381	=item IO::AIO::mlockall $flags
		2382
		2383	Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
		2384	but is blocking.
1982		2385
1983	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef	2386	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1984		2387
1985	Calls the C<munlock> function, undoing the effects of a previous	2388	Calls the C<munlock> function, undoing the effects of a previous
1986	C<aio_mlock> call (see its description for details).	2389	C<aio_mlock> call (see its description for details).
…		…
2007		2410
2008	See the C<splice(2)> manpage for details.	2411	See the C<splice(2)> manpage for details.
2009		2412
2010	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags	2413	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2011		2414
2012	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the	2415	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2013	description for C<IO::AIO::splice> above for details.	2416	description for C<IO::AIO::splice> above for details.
		2417
		2418	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2419
		2420	Attempts to query or change the pipe buffer size. Obviously works only
		2421	on pipes, and currently works only on GNU/Linux systems, and fails with
		2422	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2423	size on other systems, drop me a note.
		2424
		2425	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2426
		2427	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2428	C<$flags> is missing or C<0>, then this should be the same as a call to
		2429	perl's built-in C<pipe> function and create a new pipe, and works on
		2430	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2431	(..., 4096, O_BINARY)>.
		2432
		2433	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2434	the given flags (Linux 2.6.27, glibc 2.9).
		2435
		2436	On success, the read and write file handles are returned.
		2437
		2438	On error, nothing will be returned. If the pipe2 syscall is missing and
		2439	C<$flags> is non-zero, fails with C<ENOSYS>.
		2440
		2441	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2442	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2443	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2444
		2445	Example: create a pipe race-free w.r.t. threads and fork:
		2446
		2447	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2448	or die "pipe2: $!\n";
		2449
		2450	=item $fh = IO::AIO::memfd_create $pathname[, $flags]
		2451
		2452	This is a direct interface to the Linux L<memfd_create(2)> system
		2453	call. The (unhelpful) default for C<$flags> is C<0>, but your default
		2454	should be C<IO::AIO::MFD_CLOEXEC>.
		2455
		2456	On success, the new memfd filehandle is returned, otherwise returns
		2457	C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
		2458
		2459	Please refer to L<memfd_create(2)> for more info on this call.
		2460
		2461	The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
		2462	C<IO::AIO::MFD_ALLOW_SEALING> and C<IO::AIO::MFD_HUGETLB>.
		2463
		2464	Example: create a new memfd.
		2465
		2466	my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
		2467	or die "m,emfd_create: $!\n";
		2468	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2469
		2470	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2471	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2472
		2473	On success, the new eventfd filehandle is returned, otherwise returns
		2474	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2475
		2476	Please refer to L<eventfd(2)> for more info on this call.
		2477
		2478	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2479	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2480
		2481	Example: create a new eventfd filehandle:
		2482
		2483	$fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
		2484	or die "eventfd: $!\n";
		2485
		2486	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2487
		2488	This is a direct interface to the Linux L<timerfd_create(2)> system
		2489	call. The (unhelpful) default for C<$flags> is C<0>, but your default
		2490	should be C<IO::AIO::TFD_CLOEXEC>.
		2491
		2492	On success, the new timerfd filehandle is returned, otherwise returns
		2493	C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
		2494
		2495	Please refer to L<timerfd_create(2)> for more info on this call.
		2496
		2497	The following C<$clockid> values are
		2498	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2499	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2500	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2501	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2502
		2503	The following C<$flags> values are available (Linux
		2504	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2505
		2506	Example: create a new timerfd and set it to one-second repeated alarms,
		2507	then wait for two alarms:
		2508
		2509	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2510	or die "timerfd_create: $!\n";
		2511
		2512	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2513	or die "timerfd_settime: $!\n";
		2514
		2515	for (1..2) {
		2516	8 == sysread $fh, my $buf, 8
		2517	or die "timerfd read failure\n";
		2518
		2519	printf "number of expirations (likely 1): %d\n",
		2520	unpack "Q", $buf;
		2521	}
		2522
		2523	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2524
		2525	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2526	call. Please refer to its manpage for more info on this call.
		2527
		2528	The new itimerspec is specified using two (possibly fractional) second
		2529	values, C<$new_interval> and C<$new_value>).
		2530
		2531	On success, the current interval and value are returned (as per
		2532	C<timerfd_gettime>). On failure, the empty list is returned.
		2533
		2534	The following C<$flags> values are
		2535	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2536	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2537
		2538	See C<IO::AIO::timerfd_create> for a full example.
		2539
		2540	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2541
		2542	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2543	call. Please refer to its manpage for more info on this call.
		2544
		2545	On success, returns the current values of interval and value for the given
		2546	timerfd (as potentially fractional second values). On failure, the empty
		2547	list is returned.
2014		2548
2015	=back	2549	=back
2016		2550
2017	=cut	2551	=cut
2018		2552
…		…
2084	the process will result in undefined behaviour. Calling it at any time	2618	the process will result in undefined behaviour. Calling it at any time
2085	will also result in any undefined (by POSIX) behaviour.	2619	will also result in any undefined (by POSIX) behaviour.
2086		2620
2087	=back	2621	=back
2088		2622
		2623	=head2 LINUX-SPECIFIC CALLS
		2624
		2625	When a call is documented as "linux-specific" then this means it
		2626	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2627	availability and compatibility of such calls regardless of the platform
		2628	it is compiled on, so platforms such as FreeBSD which often implement
		2629	these calls will work. When in doubt, call them and see if they fail wth
		2630	C<ENOSYS>.
		2631
2089	=head2 MEMORY USAGE	2632	=head2 MEMORY USAGE
2090		2633
2091	Per-request usage:	2634	Per-request usage:
2092		2635
2093	Each aio request uses - depending on your architecture - around 100-200	2636	Each aio request uses - depending on your architecture - around 100-200
…		…
2105	temporary buffers, and each thread requires a stack and other data	2648	temporary buffers, and each thread requires a stack and other data
2106	structures (usually around 16k-128k, depending on the OS).	2649	structures (usually around 16k-128k, depending on the OS).
2107		2650
2108	=head1 KNOWN BUGS	2651	=head1 KNOWN BUGS
2109		2652
2110	Known bugs will be fixed in the next release.	2653	Known bugs will be fixed in the next release :)
		2654
		2655	=head1 KNOWN ISSUES
		2656
		2657	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2658	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2659	non-created hash slots or other scalars I didn't think of. It's best to
		2660	avoid such and either use scalar variables or making sure that the scalar
		2661	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2662
		2663	I am not sure anything can be done about this, so this is considered a
		2664	known issue, rather than a bug.
2111		2665
2112	=head1 SEE ALSO	2666	=head1 SEE ALSO
2113		2667
2114	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2668	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2115	more natural syntax.	2669	more natural syntax.

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.230 by root, Fri Jul 27 17:24:06 2012 UTC vs. Revision 1.302 by root, Wed Apr 3 03:03:53 2019 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.230 by root, Fri Jul 27 17:24:06 2012 UTC vs.
Revision 1.302 by root, Wed Apr 3 03:03:53 2019 UTC