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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.228 by root, Sun Jun 17 17:07:25 2012 UTC vs.
Revision 1.300 by root, Sun Mar 10 12:11:46 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 = 4.71;
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
…		…
202		206
203	=head1 FUNCTIONS	207	=head1 FUNCTIONS
204		208
205	=head2 QUICK OVERVIEW	209	=head2 QUICK OVERVIEW
206		210
207	This section simply lists the prototypes of the most important functions	211	This section simply lists the prototypes most of the functions for
208	for quick reference. See the following sections for function-by-function	212	quick reference. See the following sections for function-by-function
209	documentation.	213	documentation.
210		214
211	aio_wd $pathname, $callback->($wd)	215	aio_wd $pathname, $callback->($wd)
212	aio_open $pathname, $flags, $mode, $callback->($fh)	216	aio_open $pathname, $flags, $mode, $callback->($fh)
213	aio_close $fh, $callback->($status)	217	aio_close $fh, $callback->($status)
…		…
221	aio_statvfs $fh_or_path, $callback->($statvfs)	225	aio_statvfs $fh_or_path, $callback->($statvfs)
222	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	226	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
223	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	227	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224	aio_chmod $fh_or_path, $mode, $callback->($status)	228	aio_chmod $fh_or_path, $mode, $callback->($status)
225	aio_truncate $fh_or_path, $offset, $callback->($status)	229	aio_truncate $fh_or_path, $offset, $callback->($status)
		230	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		231	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
226	aio_unlink $pathname, $callback->($status)	232	aio_unlink $pathname, $callback->($status)
227	aio_mknod $pathname, $mode, $dev, $callback->($status)	233	aio_mknod $pathname, $mode, $dev, $callback->($status)
228	aio_link $srcpath, $dstpath, $callback->($status)	234	aio_link $srcpath, $dstpath, $callback->($status)
229	aio_symlink $srcpath, $dstpath, $callback->($status)	235	aio_symlink $srcpath, $dstpath, $callback->($status)
230	aio_readlink $pathname, $callback->($link)	236	aio_readlink $pathname, $callback->($link)
231	aio_realpath $pathname, $callback->($link)	237	aio_realpath $pathname, $callback->($path)
232	aio_rename $srcpath, $dstpath, $callback->($status)	238	aio_rename $srcpath, $dstpath, $callback->($status)
		239	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
233	aio_mkdir $pathname, $mode, $callback->($status)	240	aio_mkdir $pathname, $mode, $callback->($status)
234	aio_rmdir $pathname, $callback->($status)	241	aio_rmdir $pathname, $callback->($status)
235	aio_readdir $pathname, $callback->($entries)	242	aio_readdir $pathname, $callback->($entries)
236	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	243	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
237	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	244	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
…		…
239	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	246	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
240	aio_load $pathname, $data, $callback->($status)	247	aio_load $pathname, $data, $callback->($status)
241	aio_copy $srcpath, $dstpath, $callback->($status)	248	aio_copy $srcpath, $dstpath, $callback->($status)
242	aio_move $srcpath, $dstpath, $callback->($status)	249	aio_move $srcpath, $dstpath, $callback->($status)
243	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)
244	aio_sync $callback->($status)	253	aio_sync $callback->($status)
245	aio_syncfs $fh, $callback->($status)	254	aio_syncfs $fh, $callback->($status)
246	aio_fsync $fh, $callback->($status)	255	aio_fsync $fh, $callback->($status)
247	aio_fdatasync $fh, $callback->($status)	256	aio_fdatasync $fh, $callback->($status)
248	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	257	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
249	aio_pathsync $pathname, $callback->($status)	258	aio_pathsync $pathname, $callback->($status)
250	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
251	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	260	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
252	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	261	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
253	aio_mlockall $flags, $callback->($status)	262	aio_mlockall $flags, $callback->($status)
254	aio_group $callback->(...)	263	aio_group $callback->(...)
255	aio_nop $callback->()	264	aio_nop $callback->()
…		…
269	IO::AIO::idle_timeout $seconds	278	IO::AIO::idle_timeout $seconds
270	IO::AIO::max_outstanding $maxreqs	279	IO::AIO::max_outstanding $maxreqs
271	IO::AIO::nreqs	280	IO::AIO::nreqs
272	IO::AIO::nready	281	IO::AIO::nready
273	IO::AIO::npending	282	IO::AIO::npending
		283	$nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
		284	IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
274		285
275	IO::AIO::sendfile $ofh, $ifh, $offset, $count	286	IO::AIO::sendfile $ofh, $ifh, $offset, $count
276	IO::AIO::fadvise $fh, $offset, $len, $advice	287	IO::AIO::fadvise $fh, $offset, $len, $advice
277	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]	288	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
278	IO::AIO::munmap $scalar	289	IO::AIO::munmap $scalar
		290	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
279	IO::AIO::madvise $scalar, $offset, $length, $advice	291	IO::AIO::madvise $scalar, $offset, $length, $advice
280	IO::AIO::mprotect $scalar, $offset, $length, $protect	292	IO::AIO::mprotect $scalar, $offset, $length, $protect
281	IO::AIO::munlock $scalar, $offset = 0, $length = undef	293	IO::AIO::munlock $scalar, $offset = 0, $length = undef
282	IO::AIO::munlockall	294	IO::AIO::munlockall
283		295
…		…
360		372
361		373
362	=item aio_open $pathname, $flags, $mode, $callback->($fh)	374	=item aio_open $pathname, $flags, $mode, $callback->($fh)
363		375
364	Asynchronously open or create a file and call the callback with a newly	376	Asynchronously open or create a file and call the callback with a newly
365	created filehandle for the file.	377	created filehandle for the file (or C<undef> in case of an error).
366		378
367	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	379	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
368	for an explanation.	380	for an explanation.
369		381
370	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	382	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
393	following POSIX and non-POSIX constants are available (missing ones on	405	following POSIX and non-POSIX constants are available (missing ones on
394	your system are, as usual, C<0>):	406	your system are, as usual, C<0>):
395		407
396	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	408	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
397	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	409	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
398	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	410	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
399		411
400		412
401	=item aio_close $fh, $callback->($status)	413	=item aio_close $fh, $callback->($status)
402		414
403	Asynchronously close a file and call the callback with the result	415	Asynchronously close a file and call the callback with the result
…		…
438	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	450	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
439		451
440	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	452	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441		453
442	Reads or writes C<$length> bytes from or to the specified C<$fh> and	454	Reads or writes C<$length> bytes from or to the specified C<$fh> and
443	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	455	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
444	and calls the callback without the actual number of bytes read (or -1 on	456	calls the callback with the actual number of bytes transferred (or -1 on
445	error, just like the syscall).	457	error, just like the syscall).
446		458
447	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	459	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
448	offset plus the actual number of bytes read.	460	offset plus the actual number of bytes read.
449		461
…		…
507	As native sendfile syscalls (as practically any non-POSIX interface hacked	519	As native sendfile syscalls (as practically any non-POSIX interface hacked
508	together in a hurry to improve benchmark numbers) tend to be rather buggy	520	together in a hurry to improve benchmark numbers) tend to be rather buggy
509	on many systems, this implementation tries to work around some known bugs	521	on many systems, this implementation tries to work around some known bugs
510	in Linux and FreeBSD kernels (probably others, too), but that might fail,	522	in Linux and FreeBSD kernels (probably others, too), but that might fail,
511	so you really really should check the return value of C<aio_sendfile> -	523	so you really really should check the return value of C<aio_sendfile> -
512	fewre bytes than expected might have been transferred.	524	fewer bytes than expected might have been transferred.
513		525
514		526
515	=item aio_readahead $fh,$offset,$length, $callback->($retval)	527	=item aio_readahead $fh,$offset,$length, $callback->($retval)
516		528
517	C<aio_readahead> populates the page cache with data from a file so that	529	C<aio_readahead> populates the page cache with data from a file so that
…		…
521	whole pages, so that offset is effectively rounded down to a page boundary	533	whole pages, so that offset is effectively rounded down to a page boundary
522	and bytes are read up to the next page boundary greater than or equal to	534	and bytes are read up to the next page boundary greater than or equal to
523	(off-set+length). C<aio_readahead> does not read beyond the end of the	535	(off-set+length). C<aio_readahead> does not read beyond the end of the
524	file. The current file offset of the file is left unchanged.	536	file. The current file offset of the file is left unchanged.
525		537
526	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	538	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
527	emulated by simply reading the data, which would have a similar effect.	539	be emulated by simply reading the data, which would have a similar effect.
528		540
529		541
530	=item aio_stat $fh_or_path, $callback->($status)	542	=item aio_stat $fh_or_path, $callback->($status)
531		543
532	=item aio_lstat $fh, $callback->($status)	544	=item aio_lstat $fh, $callback->($status)
533		545
534	Works like perl's C<stat> or C<lstat> in void context. The callback will	546	Works almost exactly like perl's C<stat> or C<lstat> in void context. The
535	be called after the stat and the results will be available using C<stat _>	547	callback will be called after the stat and the results will be available
536	or C<-s _> etc...	548	using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
		549	and C<-T>).
537		550
538	The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,	551	The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
539	for an explanation.	552	for an explanation.
540		553
541	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	554	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
…		…
548	behaviour).	561	behaviour).
549		562
550	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,	563	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
551	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,	564	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
552	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.	565	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		566
		567	To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
		568	ACCESS>.
553		569
554	Example: Print the length of F</etc/passwd>:	570	Example: Print the length of F</etc/passwd>:
555		571
556	aio_stat "/etc/passwd", sub {	572	aio_stat "/etc/passwd", sub {
557	$_[0] and die "stat failed: $!";	573	$_[0] and die "stat failed: $!";
…		…
601	namemax => 255,	617	namemax => 255,
602	frsize => 1024,	618	frsize => 1024,
603	fsid => 1810	619	fsid => 1810
604	}	620	}
605		621
606
607	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	622	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
608		623
609	Works like perl's C<utime> function (including the special case of $atime	624	Works like perl's C<utime> function (including the special case of $atime
610	and $mtime being undef). Fractional times are supported if the underlying	625	and $mtime being undef). Fractional times are supported if the underlying
611	syscalls support them.	626	syscalls support them.
612		627
613	When called with a pathname, uses utimes(2) if available, otherwise	628	When called with a pathname, uses utimensat(2) or utimes(2) if available,
614	utime(2). If called on a file descriptor, uses futimes(2) if available,	629	otherwise utime(2). If called on a file descriptor, uses futimens(2)
615	otherwise returns ENOSYS, so this is not portable.	630	or futimes(2) if available, otherwise returns ENOSYS, so this is not
		631	portable.
616		632
617	Examples:	633	Examples:
618		634
619	# set atime and mtime to current time (basically touch(1)):	635	# set atime and mtime to current time (basically touch(1)):
620	aio_utime "path", undef, undef;	636	aio_utime "path", undef, undef;
…		…
638	=item aio_truncate $fh_or_path, $offset, $callback->($status)	654	=item aio_truncate $fh_or_path, $offset, $callback->($status)
639		655
640	Works like truncate(2) or ftruncate(2).	656	Works like truncate(2) or ftruncate(2).
641		657
642		658
		659	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		660
		661	Allocates or frees disk space according to the C<$mode> argument. See the
		662	linux C<fallocate> documentation for details.
		663
		664	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		665	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		666	to deallocate a file range.
		667
		668	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		669	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		670	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		671	to unshare shared blocks (see your L<fallocate(2)> manpage).
		672
		673	The file system block size used by C<fallocate> is presumably the
		674	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		675	can dictate other limitations.
		676
		677	If C<fallocate> isn't available or cannot be emulated (currently no
		678	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		679
		680
643	=item aio_chmod $fh_or_path, $mode, $callback->($status)	681	=item aio_chmod $fh_or_path, $mode, $callback->($status)
644		682
645	Works like perl's C<chmod> function.	683	Works like perl's C<chmod> function.
646		684
647		685
…		…
684		722
685		723
686	=item aio_realpath $pathname, $callback->($path)	724	=item aio_realpath $pathname, $callback->($path)
687		725
688	Asynchronously make the path absolute and resolve any symlinks in	726	Asynchronously make the path absolute and resolve any symlinks in
689	C<$path>. The resulting path only consists of directories (Same as	727	C<$path>. The resulting path only consists of directories (same as
690	L<Cwd::realpath>).	728	L<Cwd::realpath>).
691		729
692	This request can be used to get the absolute path of the current working	730	This request can be used to get the absolute path of the current working
693	directory by passing it a path of F<.> (a single dot).	731	directory by passing it a path of F<.> (a single dot).
694		732
695		733
696	=item aio_rename $srcpath, $dstpath, $callback->($status)	734	=item aio_rename $srcpath, $dstpath, $callback->($status)
697		735
698	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	736	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
699	rename(2) and call the callback with the result code.	737	rename(2) and call the callback with the result code.
		738
		739	On systems that support the AIO::WD working directory abstraction
		740	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		741	of failing, C<rename> is called on the absolute path of C<$wd>.
		742
		743
		744	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		745
		746	Basically a version of C<aio_rename> with an additional C<$flags>
		747	argument. Calling this with C<$flags=0> is the same as calling
		748	C<aio_rename>.
		749
		750	Non-zero flags are currently only supported on GNU/Linux systems that
		751	support renameat2. Other systems fail with C<ENOSYS> in this case.
		752
		753	The following constants are available (missing ones are, as usual C<0>),
		754	see renameat2(2) for details:
		755
		756	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		757	and C<IO::AIO::RENAME_WHITEOUT>.
700		758
701		759
702	=item aio_mkdir $pathname, $mode, $callback->($status)	760	=item aio_mkdir $pathname, $mode, $callback->($status)
703		761
704	Asynchronously mkdir (create) a directory and call the callback with	762	Asynchronously mkdir (create) a directory and call the callback with
…		…
709	=item aio_rmdir $pathname, $callback->($status)	767	=item aio_rmdir $pathname, $callback->($status)
710		768
711	Asynchronously rmdir (delete) a directory and call the callback with the	769	Asynchronously rmdir (delete) a directory and call the callback with the
712	result code.	770	result code.
713		771
		772	On systems that support the AIO::WD working directory abstraction
		773	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		774	C<rmdir> is called on the absolute path of C<$wd>.
		775
714		776
715	=item aio_readdir $pathname, $callback->($entries)	777	=item aio_readdir $pathname, $callback->($entries)
716		778
717	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	779	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
718	directory (i.e. opendir + readdir + closedir). The entries will not be	780	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
733		795
734	=over 4	796	=over 4
735		797
736	=item IO::AIO::READDIR_DENTS	798	=item IO::AIO::READDIR_DENTS
737		799
738	When this flag is off, then the callback gets an arrayref consisting of	800	Normally the callback gets an arrayref consisting of names only (as
739	names only (as with C<aio_readdir>), otherwise it gets an arrayref with	801	with C<aio_readdir>). If this flag is set, then the callback gets an
740	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	802	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
741	entry in more detail.	803	single directory entry in more detail:
742		804
743	C<$name> is the name of the entry.	805	C<$name> is the name of the entry.
744		806
745	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	807	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
746		808
747	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	809	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
748	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	810	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
749	C<IO::AIO::DT_WHT>.	811	C<IO::AIO::DT_WHT>.
750		812
751	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	813	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
752	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	814	to know, you have to run stat yourself. Also, for speed/memory reasons,
753	scalars are read-only: you can not modify them.	815	the C<$type> scalars are read-only: you must not modify them.
754		816
755	C<$inode> is the inode number (which might not be exact on systems with 64	817	C<$inode> is the inode number (which might not be exact on systems with 64
756	bit inode numbers and 32 bit perls). This field has unspecified content on	818	bit inode numbers and 32 bit perls). This field has unspecified content on
757	systems that do not deliver the inode information.	819	systems that do not deliver the inode information.
758		820
…		…
769	short names are tried first.	831	short names are tried first.
770		832
771	=item IO::AIO::READDIR_STAT_ORDER	833	=item IO::AIO::READDIR_STAT_ORDER
772		834
773	When this flag is set, then the names will be returned in an order	835	When this flag is set, then the names will be returned in an order
774	suitable for stat()'ing each one. That is, when you plan to stat()	836	suitable for stat()'ing each one. That is, when you plan to stat() most or
775	all files in the given directory, then the returned order will likely	837	all files in the given directory, then the returned order will likely be
776	be fastest.	838	faster.
777		839
778	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	840	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
779	the likely dirs come first, resulting in a less optimal stat order.	841	then the likely dirs come first, resulting in a less optimal stat order
		842	for stat'ing all entries, but likely a more optimal order for finding
		843	subdirectories.
780		844
781	=item IO::AIO::READDIR_FOUND_UNKNOWN	845	=item IO::AIO::READDIR_FOUND_UNKNOWN
782		846
783	This flag should not be set when calling C<aio_readdirx>. Instead, it	847	This flag should not be set when calling C<aio_readdirx>. Instead, it
784	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	848	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
786	C<$type>'s are known, which can be used to speed up some algorithms.	850	C<$type>'s are known, which can be used to speed up some algorithms.
787		851
788	=back	852	=back
789		853
790		854
		855	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		856
		857	Opens, reads and closes the given file. The data is put into C<$data>,
		858	which is resized as required.
		859
		860	If C<$offset> is negative, then it is counted from the end of the file.
		861
		862	If C<$length> is zero, then the remaining length of the file is
		863	used. Also, in this case, the same limitations to modifying C<$data> apply
		864	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		865	with C<substr>. If the size of the file is known, specifying a non-zero
		866	C<$length> results in a performance advantage.
		867
		868	This request is similar to the older C<aio_load> request, but since it is
		869	a single request, it might be more efficient to use.
		870
		871	Example: load F</etc/passwd> into C<$passwd>.
		872
		873	my $passwd;
		874	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		875	$_[0] >= 0
		876	or die "/etc/passwd: $!\n";
		877
		878	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		879	print $passwd;
		880	};
		881	IO::AIO::flush;
		882
		883
791	=item aio_load $pathname, $data, $callback->($status)	884	=item aio_load $pathname, $data, $callback->($status)
792		885
793	This is a composite request that tries to fully load the given file into	886	This is a composite request that tries to fully load the given file into
794	memory. Status is the same as with aio_read.	887	memory. Status is the same as with aio_read.
		888
		889	Using C<aio_slurp> might be more efficient, as it is a single request.
795		890
796	=cut	891	=cut
797		892
798	sub aio_load($$;$) {	893	sub aio_load($$;$) {
799	my ($path, undef, $cb) = @_;	894	my ($path, undef, $cb) = @_;
…		…
819	=item aio_copy $srcpath, $dstpath, $callback->($status)	914	=item aio_copy $srcpath, $dstpath, $callback->($status)
820		915
821	Try to copy the I<file> (directories not supported as either source or	916	Try to copy the I<file> (directories not supported as either source or
822	destination) from C<$srcpath> to C<$dstpath> and call the callback with	917	destination) from C<$srcpath> to C<$dstpath> and call the callback with
823	a status of C<0> (ok) or C<-1> (error, see C<$!>).	918	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		919
		920	Existing destination files will be truncated.
824		921
825	This is a composite request that creates the destination file with	922	This is a composite request that creates the destination file with
826	mode 0200 and copies the contents of the source file into it using	923	mode 0200 and copies the contents of the source file into it using
827	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	924	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
828	uid/gid, in that order.	925	uid/gid, in that order.
…		…
938	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1035	Scans a directory (similar to C<aio_readdir>) but additionally tries to
939	efficiently separate the entries of directory C<$path> into two sets of	1036	efficiently separate the entries of directory C<$path> into two sets of
940	names, directories you can recurse into (directories), and ones you cannot	1037	names, directories you can recurse into (directories), and ones you cannot
941	recurse into (everything else, including symlinks to directories).	1038	recurse into (everything else, including symlinks to directories).
942		1039
943	C<aio_scandir> is a composite request that creates of many sub requests_	1040	C<aio_scandir> is a composite request that generates many sub requests.
944	C<$maxreq> specifies the maximum number of outstanding aio requests that	1041	C<$maxreq> specifies the maximum number of outstanding aio requests that
945	this function generates. If it is C<< <= 0 >>, then a suitable default	1042	this function generates. If it is C<< <= 0 >>, then a suitable default
946	will be chosen (currently 4).	1043	will be chosen (currently 4).
947		1044
948	On error, the callback is called without arguments, otherwise it receives	1045	On error, the callback is called without arguments, otherwise it receives
…		…
1012	aioreq_pri $pri;	1109	aioreq_pri $pri;
1013	add $grp aio_stat $wd, sub {	1110	add $grp aio_stat $wd, sub {
1014	return $grp->result () if $_[0];	1111	return $grp->result () if $_[0];
1015	my $now = time;	1112	my $now = time;
1016	my $hash1 = join ":", (stat _)[0,1,3,7,9];	1113	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		1114	my $rdxflags = READDIR_DIRS_FIRST;
		1115
		1116	if ((stat _)[3] < 2) {
		1117	# at least one non-POSIX filesystem exists
		1118	# that returns useful DT_type values: btrfs,
		1119	# so optimise for this here by requesting dents
		1120	$rdxflags \|= READDIR_DENTS;
		1121	}
1017		1122
1018	# read the directory entries	1123	# read the directory entries
1019	aioreq_pri $pri;	1124	aioreq_pri $pri;
1020	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {	1125	add $grp aio_readdirx $wd, $rdxflags, sub {
1021	my $entries = shift	1126	my ($entries, $flags) = @_
1022	or return $grp->result ();	1127	or return $grp->result ();
		1128
		1129	if ($rdxflags & READDIR_DENTS) {
		1130	# if we requested type values, see if we can use them directly.
		1131
		1132	# if there were any DT_UNKNOWN entries then we assume we
		1133	# don't know. alternatively, we could assume that if we get
		1134	# one DT_DIR, then all directories are indeed marked with
		1135	# DT_DIR, but this seems not required for btrfs, and this
		1136	# is basically the "btrfs can't get it's act together" code
		1137	# branch.
		1138	unless ($flags & READDIR_FOUND_UNKNOWN) {
		1139	# now we have valid DT_ information for all entries,
		1140	# so use it as an optimisation without further stat's.
		1141	# they must also all be at the beginning of @$entries
		1142	# by now.
		1143
		1144	my $dirs;
		1145
		1146	if (@$entries) {
		1147	for (0 .. $#$entries) {
		1148	if ($entries->[$_][1] != DT_DIR) {
		1149	# splice out directories
		1150	$dirs = [splice @$entries, 0, $_];
		1151	last;
		1152	}
		1153	}
		1154
		1155	# if we didn't find any non-dir, then all entries are dirs
		1156	unless ($dirs) {
		1157	($dirs, $entries) = ($entries, []);
		1158	}
		1159	} else {
		1160	# directory is empty, so there are no sbdirs
		1161	$dirs = [];
		1162	}
		1163
		1164	# either splice'd the directories out or the dir was empty.
		1165	# convert dents to filenames
		1166	$_ = $_->[0] for @$dirs;
		1167	$_ = $_->[0] for @$entries;
		1168
		1169	return $grp->result ($dirs, $entries);
		1170	}
		1171
		1172	# cannot use, so return to our old ways
		1173	# by pretending we only scanned for names.
		1174	$_ = $_->[0] for @$entries;
		1175	}
1023		1176
1024	# stat the dir another time	1177	# stat the dir another time
1025	aioreq_pri $pri;	1178	aioreq_pri $pri;
1026	add $grp aio_stat $wd, sub {	1179	add $grp aio_stat $wd, sub {
1027	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1180	my $hash2 = join ":", (stat _)[0,1,3,7,9];
…		…
1082	}	1235	}
1083		1236
1084	=item aio_rmtree $pathname, $callback->($status)	1237	=item aio_rmtree $pathname, $callback->($status)
1085		1238
1086	Delete a directory tree starting (and including) C<$path>, return the	1239	Delete a directory tree starting (and including) C<$path>, return the
1087	status of the final C<rmdir> only. This is a composite request that	1240	status of the final C<rmdir> only. This is a composite request that
1088	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1241	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1089	everything else.	1242	everything else.
1090		1243
1091	=cut	1244	=cut
1092		1245
…		…
1113	add $grp $dirgrp;	1266	add $grp $dirgrp;
1114	};	1267	};
1115		1268
1116	$grp	1269	$grp
1117	}	1270	}
		1271
		1272	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1273
		1274	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1275
		1276	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1277	they execute asynchronously and pass the return value to the callback.
		1278
		1279	Both calls can be used for a lot of things, some of which make more sense
		1280	to run asynchronously in their own thread, while some others make less
		1281	sense. For example, calls that block waiting for external events, such
		1282	as locking, will also lock down an I/O thread while it is waiting, which
		1283	can deadlock the whole I/O system. At the same time, there might be no
		1284	alternative to using a thread to wait.
		1285
		1286	So in general, you should only use these calls for things that do
		1287	(filesystem) I/O, not for things that wait for other events (network,
		1288	other processes), although if you are careful and know what you are doing,
		1289	you still can.
		1290
		1291	The following constants are available (missing ones are, as usual C<0>):
		1292
		1293	C<F_DUPFD_CLOEXEC>,
		1294
		1295	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1296
		1297	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1298
		1299	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1300	C<FS_IOC_FIEMAP>.
		1301
		1302	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1303	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1304
		1305	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1306	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1307	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1308	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1309	C<FS_FL_USER_MODIFIABLE>.
		1310
		1311	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1312	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1313	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1314	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1118		1315
1119	=item aio_sync $callback->($status)	1316	=item aio_sync $callback->($status)
1120		1317
1121	Asynchronously call sync and call the callback when finished.	1318	Asynchronously call sync and call the callback when finished.
1122		1319
…		…
1191	};	1388	};
1192		1389
1193	$grp	1390	$grp
1194	}	1391	}
1195		1392
1196	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1393	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1197		1394
1198	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1395	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1199	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1396	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1200	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1397	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1201	scalar must only be modified in-place while an aio operation is pending on	1398	scalar must only be modified in-place while an aio operation is pending on
…		…
1203		1400
1204	It calls the C<msync> function of your OS, if available, with the memory	1401	It calls the C<msync> function of your OS, if available, with the memory
1205	area starting at C<$offset> in the string and ending C<$length> bytes	1402	area starting at C<$offset> in the string and ending C<$length> bytes
1206	later. If C<$length> is negative, counts from the end, and if C<$length>	1403	later. If C<$length> is negative, counts from the end, and if C<$length>
1207	is C<undef>, then it goes till the end of the string. The flags can be	1404	is C<undef>, then it goes till the end of the string. The flags can be
1208	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1405	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1209	C<IO::AIO::MS_SYNC>.	1406	C<IO::AIO::MS_INVALIDATE>.
1210		1407
1211	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1408	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1212		1409
1213	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1410	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1214	scalars.	1411	scalars.
1215		1412
1216	It touches (reads or writes) all memory pages in the specified	1413	It touches (reads or writes) all memory pages in the specified
1217	range inside the scalar. All caveats and parameters are the same	1414	range inside the scalar. All caveats and parameters are the same
1218	as for C<aio_msync>, above, except for flags, which must be either	1415	as for C<aio_msync>, above, except for flags, which must be either
1219	C<0> (which reads all pages and ensures they are instantiated) or	1416	C<0> (which reads all pages and ensures they are instantiated) or
1220	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1417	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1221	writing an octet from it, which dirties the page).	1418	writing an octet from it, which dirties the page).
1222		1419
1223	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1420	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1224		1421
1225	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1422	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1244	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;	1441	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1245	aio_mlock $data; # mlock in background	1442	aio_mlock $data; # mlock in background
1246		1443
1247	=item aio_mlockall $flags, $callback->($status)	1444	=item aio_mlockall $flags, $callback->($status)
1248		1445
1249	Calls the C<mlockall> function with the given C<$flags> (a combination of	1446	Calls the C<mlockall> function with the given C<$flags> (a
1250	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).	1447	combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
		1448	C<IO::AIO::MCL_ONFAULT>).
1251		1449
1252	On systems that do not implement C<mlockall>, this function returns C<-1>	1450	On systems that do not implement C<mlockall>, this function returns C<-1>
1253	and sets errno to C<ENOSYS>.	1451	and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
		1452	by the system result in a return value of C<-1> with errno being set to
		1453	C<EINVAL>.
1254		1454
1255	Note that the corresponding C<munlockall> is synchronous and is	1455	Note that the corresponding C<munlockall> is synchronous and is
1256	documented under L<MISCELLANEOUS FUNCTIONS>.	1456	documented under L<MISCELLANEOUS FUNCTIONS>.
1257		1457
1258	Example: asynchronously lock all current and future pages into memory.	1458	Example: asynchronously lock all current and future pages into memory.
1259		1459
1260	aio_mlockall IO::AIO::MCL_FUTURE;	1460	aio_mlockall IO::AIO::MCL_FUTURE;
1261		1461
1262	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)	1462	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1263		1463
1264	Queries the extents of the given file (by calling the Linux FIEMAP ioctl,	1464	Queries the extents of the given file (by calling the Linux C<FIEMAP>
1265	see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the	1465	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1266	C<ioctl> is not available on your OS, then this rquiest will fail with	1466	the ioctl is not available on your OS, then this request will fail with
1267	C<ENOSYS>.	1467	C<ENOSYS>.
1268		1468
1269	C<$start> is the starting offset to query extents for, C<$length> is the	1469	C<$start> is the starting offset to query extents for, C<$length> is the
1270	size of the range to query - if it is C<undef>, then the whole file will	1470	size of the range to query - if it is C<undef>, then the whole file will
1271	be queried.	1471	be queried.
…		…
1274	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also	1474	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1275	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query	1475	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1276	the data portion.	1476	the data portion.
1277		1477
1278	C<$count> is the maximum number of extent records to return. If it is	1478	C<$count> is the maximum number of extent records to return. If it is
1279	C<undef>, then IO::AIO queries all extents of the file. As a very special	1479	C<undef>, then IO::AIO queries all extents of the range. As a very special
1280	case, if it is C<0>, then the callback receives the number of extents	1480	case, if it is C<0>, then the callback receives the number of extents
1281	instead of the extents themselves.	1481	instead of the extents themselves (which is unreliable, see below).
1282		1482
1283	If an error occurs, the callback receives no arguments. The special	1483	If an error occurs, the callback receives no arguments. The special
1284	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.	1484	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1285		1485
1286	Otherwise, the callback receives an array reference with extent	1486	Otherwise, the callback receives an array reference with extent
…		…
1288	following members:	1488	following members:
1289		1489
1290	[$logical, $physical, $length, $flags]	1490	[$logical, $physical, $length, $flags]
1291		1491
1292	Flags is any combination of the following flag values (typically either C<0>	1492	Flags is any combination of the following flag values (typically either C<0>
1293	or C<IO::AIO::FIEMAP_EXTENT_LAST>):	1493	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1294		1494
1295	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,	1495	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1296	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,	1496	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1297	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,	1497	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1298	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,	1498	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1299	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or	1499	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1300	C<IO::AIO::FIEMAP_EXTENT_SHARED>.	1500	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1301		1501
		1502	At the time of this writing (Linux 3.2), this request is unreliable unless
		1503	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1504	it to return all extents of a range for files with a large number of
		1505	extents. The code (only) works around all these issues if C<$count> is
		1506	C<undef>.
		1507
1302	=item aio_group $callback->(...)	1508	=item aio_group $callback->(...)
1303		1509
1304	This is a very special aio request: Instead of doing something, it is a	1510	This is a very special aio request: Instead of doing something, it is a
1305	container for other aio requests, which is useful if you want to bundle	1511	container for other aio requests, which is useful if you want to bundle
1306	many requests into a single, composite, request with a definite callback	1512	many requests into a single, composite, request with a definite callback
…		…
1389	aio_stat [$etcdir, "passwd"], sub {	1595	aio_stat [$etcdir, "passwd"], sub {
1390	# yay	1596	# yay
1391	};	1597	};
1392	};	1598	};
1393		1599
1394	That C<aio_wd> is a request and not a normal function shows that creating	1600	The fact that C<aio_wd> is a request and not a normal function shows that
1395	an IO::AIO::WD object is itself a potentially blocking operation, which is	1601	creating an IO::AIO::WD object is itself a potentially blocking operation,
1396	why it is done asynchronously.	1602	which is why it is done asynchronously.
1397		1603
1398	To stat the directory obtained with C<aio_wd> above, one could write	1604	To stat the directory obtained with C<aio_wd> above, one could write
1399	either of the following three request calls:	1605	either of the following three request calls:
1400		1606
1401	aio_lstat "/etc" , sub { ... # pathname as normal string	1607	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1418	There are some caveats: when directories get renamed (or deleted), the	1624	There are some caveats: when directories get renamed (or deleted), the
1419	pathname string doesn't change, so will point to the new directory (or	1625	pathname string doesn't change, so will point to the new directory (or
1420	nowhere at all), while the directory fd, if available on the system,	1626	nowhere at all), while the directory fd, if available on the system,
1421	will still point to the original directory. Most functions accepting a	1627	will still point to the original directory. Most functions accepting a
1422	pathname will use the directory fd on newer systems, and the string on	1628	pathname will use the directory fd on newer systems, and the string on
1423	older systems. Some functions (such as realpath) will always rely on the	1629	older systems. Some functions (such as C<aio_realpath>) will always rely on
1424	string form of the pathname.	1630	the string form of the pathname.
1425		1631
1426	So this fucntionality is mainly useful to get some protection against	1632	So this functionality is mainly useful to get some protection against
1427	C<chdir>, to easily get an absolute path out of a relative path for future	1633	C<chdir>, to easily get an absolute path out of a relative path for future
1428	reference, and to speed up doing many operations in the same directory	1634	reference, and to speed up doing many operations in the same directory
1429	(e.g. when stat'ing all files in a directory).	1635	(e.g. when stat'ing all files in a directory).
1430		1636
1431	The following functions implement this working directory abstraction:	1637	The following functions implement this working directory abstraction:
…		…
1444	passing C<undef> as working directory component of a pathname fails the	1650	passing C<undef> as working directory component of a pathname fails the
1445	request with C<ENOENT>, there is often no need for error checking in the	1651	request with C<ENOENT>, there is often no need for error checking in the
1446	C<aio_wd> callback, as future requests using the value will fail in the	1652	C<aio_wd> callback, as future requests using the value will fail in the
1447	expected way.	1653	expected way.
1448		1654
1449	If this call isn't available because your OS lacks it or it couldn't be
1450	detected, it will be emulated by calling C<fsync> instead.
1451
1452	=item IO::AIO::CWD	1655	=item IO::AIO::CWD
1453		1656
1454	This is a compiletime constant (object) that represents the process	1657	This is a compiletime constant (object) that represents the process
1455	current working directory.	1658	current working directory.
1456		1659
1457	Specifying this object as working directory object for a pathname is as	1660	Specifying this object as working directory object for a pathname is as if
1458	if the pathname would be specified directly, without a directory object,	1661	the pathname would be specified directly, without a directory object. For
1459	e.g., these calls are functionally identical:	1662	example, these calls are functionally identical:
1460		1663
1461	aio_stat "somefile", sub { ... };	1664	aio_stat "somefile", sub { ... };
1462	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1665	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1463		1666
1464	=back	1667	=back
1465		1668
		1669	To recover the path associated with an IO::AIO::WD object, you can use
		1670	C<aio_realpath>:
		1671
		1672	aio_realpath $wd, sub {
		1673	warn "path is $_[0]\n";
		1674	};
		1675
		1676	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1677	sometimes, fall back to using an absolue path.
1466		1678
1467	=head2 IO::AIO::REQ CLASS	1679	=head2 IO::AIO::REQ CLASS
1468		1680
1469	All non-aggregate C<aio_*> functions return an object of this class when	1681	All non-aggregate C<aio_*> functions return an object of this class when
1470	called in non-void context.	1682	called in non-void context.
…		…
1631	The default value for the limit is C<0>, but note that setting a feeder	1843	The default value for the limit is C<0>, but note that setting a feeder
1632	automatically bumps it up to C<2>.	1844	automatically bumps it up to C<2>.
1633		1845
1634	=back	1846	=back
1635		1847
		1848
1636	=head2 SUPPORT FUNCTIONS	1849	=head2 SUPPORT FUNCTIONS
1637		1850
1638	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1851	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1639		1852
1640	=over 4	1853	=over 4
…		…
1648		1861
1649	See C<poll_cb> for an example.	1862	See C<poll_cb> for an example.
1650		1863
1651	=item IO::AIO::poll_cb	1864	=item IO::AIO::poll_cb
1652		1865
1653	Process some outstanding events on the result pipe. You have to call	1866	Process some requests that have reached the result phase (i.e. they have
		1867	been executed but the results are not yet reported). You have to call
		1868	this "regularly" to finish outstanding requests.
		1869
1654	this regularly. Returns C<0> if all events could be processed (or there	1870	Returns C<0> if all events could be processed (or there were no
1655	were no events to process), or C<-1> if it returned earlier for whatever	1871	events to process), or C<-1> if it returned earlier for whatever
1656	reason. Returns immediately when no events are outstanding. The amount of	1872	reason. Returns immediately when no events are outstanding. The amount
1657	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1873	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1658	C<IO::AIO::max_poll_time>.	1874	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1659		1875
1660	If not all requests were processed for whatever reason, the filehandle	1876	If not all requests were processed for whatever reason, the poll file
1661	will still be ready when C<poll_cb> returns, so normally you don't have to	1877	descriptor will still be ready when C<poll_cb> returns, so normally you
1662	do anything special to have it called later.	1878	don't have to do anything special to have it called later.
1663		1879
1664	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1880	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1665	ready, it can be beneficial to call this function from loops which submit	1881	ready, it can be beneficial to call this function from loops which submit
1666	a lot of requests, to make sure the results get processed when they become	1882	a lot of requests, to make sure the results get processed when they become
1667	available and not just when the loop is finished and the event loop takes	1883	available and not just when the loop is finished and the event loop takes
…		…
1676	poll => 'r', async => 1,	1892	poll => 'r', async => 1,
1677	cb => \&IO::AIO::poll_cb);	1893	cb => \&IO::AIO::poll_cb);
1678		1894
1679	=item IO::AIO::poll_wait	1895	=item IO::AIO::poll_wait
1680		1896
1681	If there are any outstanding requests and none of them in the result	1897	Wait until either at least one request is in the result phase or no
1682	phase, wait till the result filehandle becomes ready for reading (simply	1898	requests are outstanding anymore.
1683	does a C<select> on the filehandle. This is useful if you want to	1899
1684	synchronously wait for some requests to finish).	1900	This is useful if you want to synchronously wait for some requests to
		1901	become ready, without actually handling them.
1685		1902
1686	See C<nreqs> for an example.	1903	See C<nreqs> for an example.
1687		1904
1688	=item IO::AIO::poll	1905	=item IO::AIO::poll
1689		1906
…		…
1700		1917
1701	Strictly equivalent to:	1918	Strictly equivalent to:
1702		1919
1703	IO::AIO::poll_wait, IO::AIO::poll_cb	1920	IO::AIO::poll_wait, IO::AIO::poll_cb
1704	while IO::AIO::nreqs;	1921	while IO::AIO::nreqs;
		1922
		1923	This function can be useful at program aborts, to make sure outstanding
		1924	I/O has been done (C<IO::AIO> uses an C<END> block which already calls
		1925	this function on normal exits), or when you are merely using C<IO::AIO>
		1926	for its more advanced functions, rather than for async I/O, e.g.:
		1927
		1928	my ($dirs, $nondirs);
		1929	IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
		1930	IO::AIO::flush;
		1931	# $dirs, $nondirs are now set
1705		1932
1706	=item IO::AIO::max_poll_reqs $nreqs	1933	=item IO::AIO::max_poll_reqs $nreqs
1707		1934
1708	=item IO::AIO::max_poll_time $seconds	1935	=item IO::AIO::max_poll_time $seconds
1709		1936
…		…
1736	poll => 'r', nice => 1,	1963	poll => 'r', nice => 1,
1737	cb => &IO::AIO::poll_cb);	1964	cb => &IO::AIO::poll_cb);
1738		1965
1739	=back	1966	=back
1740		1967
		1968
1741	=head3 CONTROLLING THE NUMBER OF THREADS	1969	=head3 CONTROLLING THE NUMBER OF THREADS
1742		1970
1743	=over	1971	=over
1744		1972
1745	=item IO::AIO::min_parallel $nthreads	1973	=item IO::AIO::min_parallel $nthreads
…		…
1810		2038
1811	This is a very bad function to use in interactive programs because it	2039	This is a very bad function to use in interactive programs because it
1812	blocks, and a bad way to reduce concurrency because it is inexact: Better	2040	blocks, and a bad way to reduce concurrency because it is inexact: Better
1813	use an C<aio_group> together with a feed callback.	2041	use an C<aio_group> together with a feed callback.
1814		2042
1815	It's main use is in scripts without an event loop - when you want to stat	2043	Its main use is in scripts without an event loop - when you want to stat
1816	a lot of files, you can write somehting like this:	2044	a lot of files, you can write something like this:
1817		2045
1818	IO::AIO::max_outstanding 32;	2046	IO::AIO::max_outstanding 32;
1819		2047
1820	for my $path (...) {	2048	for my $path (...) {
1821	aio_stat $path , ...;	2049	aio_stat $path , ...;
…		…
1832	The default value for C<max_outstanding> is very large, so there is no	2060	The default value for C<max_outstanding> is very large, so there is no
1833	practical limit on the number of outstanding requests.	2061	practical limit on the number of outstanding requests.
1834		2062
1835	=back	2063	=back
1836		2064
		2065
1837	=head3 STATISTICAL INFORMATION	2066	=head3 STATISTICAL INFORMATION
1838		2067
1839	=over	2068	=over
1840		2069
1841	=item IO::AIO::nreqs	2070	=item IO::AIO::nreqs
…		…
1858	Returns the number of requests currently in the pending state (executed,	2087	Returns the number of requests currently in the pending state (executed,
1859	but not yet processed by poll_cb).	2088	but not yet processed by poll_cb).
1860		2089
1861	=back	2090	=back
1862		2091
		2092
		2093	=head3 SUBSECOND STAT TIME ACCESS
		2094
		2095	Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
		2096	generally find access/modification and change times with subsecond time
		2097	accuracy of the system supports it, but perl's built-in functions only
		2098	return the integer part.
		2099
		2100	The following functions return the timestamps of the most recent
		2101	stat with subsecond precision on most systems and work both after
		2102	C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
		2103	value is only meaningful after a successful C<stat>/C<lstat> call, or
		2104	during/after a successful C<aio_stat>/C<aio_lstat> callback.
		2105
		2106	This is similar to the L<Time::HiRes> C<stat> functions, but can return
		2107	full resolution without rounding and work with standard perl C<stat>,
		2108	alleviating the need to call the special C<Time::HiRes> functions, which
		2109	do not act like their perl counterparts.
		2110
		2111	On operating systems or file systems where subsecond time resolution is
		2112	not supported or could not be detected, a fractional part of C<0> is
		2113	returned, so it is always safe to call these functions.
		2114
		2115	=over 4
		2116
		2117	=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		2118
		2119	Return the access, modication, change or birth time, respectively,
		2120	including fractional part. Due to the limited precision of floating point,
		2121	the accuracy on most platforms is only a bit better than milliseconds
		2122	for times around now - see the I<nsec> function family, below, for full
		2123	accuracy.
		2124
		2125	File birth time is only available when the OS and perl support it (on
		2126	FreeBSD and NetBSD at the time of this writing, although support is
		2127	adaptive, so if your OS/perl gains support, IO::AIO can take avdantage of
		2128	it). On systems where it isn't available, C<0> is currently returned, but
		2129	this might change to C<undef> in a future version.
		2130
		2131	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		2132
		2133	Returns access, modification, change and birth time all in one go, and
		2134	maybe more times in the future version.
		2135
		2136	=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		2137
		2138	Return the fractional access, modifcation, change or birth time, in nanoseconds,
		2139	as an integer in the range C<0> to C<999999999>.
		2140
		2141	Note that no accessors are provided for access, modification and
		2142	change times - you need to get those from C<stat _> if required (C<int
		2143	IO::AIO::st_atime> and so on will I<not> generally give you the correct
		2144	value).
		2145
		2146	=item $seconds = IO::AIO::st_btimesec
		2147
		2148	The (integral) seconds part of the file birth time, if available.
		2149
		2150	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		2151
		2152	Like the functions above, but returns all four times in one go (and maybe
		2153	more in future versions).
		2154
		2155	=item $counter = IO::AIO::st_gen
		2156
		2157	Returns the generation counter (in practice this is just a random number)
		2158	of the file. This is only available on platforms which have this member in
		2159	their C<struct stat> (most BSDs at the time of this writing) and generally
		2160	only to the root usert. If unsupported, C<0> is returned, but this might
		2161	change to C<undef> in a future version.
		2162
		2163	=back
		2164
		2165	Example: print the high resolution modification time of F</etc>, using
		2166	C<stat>, and C<IO::AIO::aio_stat>.
		2167
		2168	if (stat "/etc") {
		2169	printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
		2170	}
		2171
		2172	IO::AIO::aio_stat "/etc", sub {
		2173	$_[0]
		2174	and return;
		2175
		2176	printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
		2177	};
		2178
		2179	IO::AIO::flush;
		2180
		2181	Output of the awbove on my system, showing reduced and full accuracy:
		2182
		2183	stat(/etc) mtime: 1534043702.020808
		2184	aio_stat(/etc) mtime: 1534043702.020807792
		2185
		2186
1863	=head3 MISCELLANEOUS FUNCTIONS	2187	=head3 MISCELLANEOUS FUNCTIONS
1864		2188
1865	IO::AIO implements some functions that might be useful, but are not	2189	IO::AIO implements some functions that are useful when you want to use
1866	asynchronous.	2190	some "Advanced I/O" function not available to in Perl, without going the
		2191	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2192	counterpart.
1867		2193
1868	=over 4	2194	=over 4
		2195
		2196	=item $numfd = IO::AIO::get_fdlimit
		2197
		2198	This function is I<EXPERIMENTAL> and subject to change.
		2199
		2200	Tries to find the current file descriptor limit and returns it, or
		2201	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2202	the highest valid file descriptor number.
		2203
		2204	=item IO::AIO::min_fdlimit [$numfd]
		2205
		2206	This function is I<EXPERIMENTAL> and subject to change.
		2207
		2208	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2209	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2210	is missing, it will try to set a very high limit, although this is not
		2211	recommended when you know the actual minimum that you require.
		2212
		2213	If the limit cannot be raised enough, the function makes a best-effort
		2214	attempt to increase the limit as much as possible, using various
		2215	tricks, while still failing. You can query the resulting limit using
		2216	C<IO::AIO::get_fdlimit>.
		2217
		2218	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2219	true.
1869		2220
1870	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2221	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1871		2222
1872	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2223	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1873	but is blocking (this makes most sense if you know the input data is	2224	but is blocking (this makes most sense if you know the input data is
…		…
1890	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2241	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1891		2242
1892	Simply calls the C<posix_madvise> function (see its	2243	Simply calls the C<posix_madvise> function (see its
1893	manpage for details). The following advice constants are	2244	manpage for details). The following advice constants are
1894	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2245	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1895	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2246	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2247	C<IO::AIO::MADV_DONTNEED>.
		2248
		2249	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2250	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2251	will be reduced to fit into the C<$scalar>.
1896		2252
1897	On systems that do not implement C<posix_madvise>, this function returns	2253	On systems that do not implement C<posix_madvise>, this function returns
1898	ENOSYS, otherwise the return value of C<posix_madvise>.	2254	ENOSYS, otherwise the return value of C<posix_madvise>.
1899		2255
1900	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2256	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1902	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2258	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1903	$scalar (see its manpage for details). The following protect	2259	$scalar (see its manpage for details). The following protect
1904	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2260	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1905	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2261	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1906		2262
		2263	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2264	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2265	will be reduced to fit into the C<$scalar>.
		2266
1907	On systems that do not implement C<mprotect>, this function returns	2267	On systems that do not implement C<mprotect>, this function returns
1908	ENOSYS, otherwise the return value of C<mprotect>.	2268	ENOSYS, otherwise the return value of C<mprotect>.
1909		2269
1910	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2270	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1911		2271
1912	Memory-maps a file (or anonymous memory range) and attaches it to the	2272	Memory-maps a file (or anonymous memory range) and attaches it to the
1913	given C<$scalar>, which will act like a string scalar. Returns true on	2273	given C<$scalar>, which will act like a string scalar. Returns true on
1914	success, and false otherwise.	2274	success, and false otherwise.
1915		2275
		2276	The scalar must exist, but its contents do not matter - this means you
		2277	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2278	the scalar first.
		2279
1916	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2280	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1917	change the string length, and most read-only operations such as copying it	2281	which don't change the string length, and most read-only operations such
1918	or searching it with regexes and so on.	2282	as copying it or searching it with regexes and so on.
1919		2283
1920	Anything else is unsafe and will, at best, result in memory leaks.	2284	Anything else is unsafe and will, at best, result in memory leaks.
1921		2285
1922	The memory map associated with the C<$scalar> is automatically removed	2286	The memory map associated with the C<$scalar> is automatically removed
1923	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2287	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1924	C<IO::AIO::munmap> functions are called.	2288	or C<IO::AIO::munmap> functions are called on it.
1925		2289
1926	This calls the C<mmap>(2) function internally. See your system's manual	2290	This calls the C<mmap>(2) function internally. See your system's manual
1927	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2291	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1928		2292
1929	The C<$length> must be larger than zero and smaller than the actual	2293	The C<$length> must be larger than zero and smaller than the actual
1930	filesize.	2294	filesize.
1931		2295
1932	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2296	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1933	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2297	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1934		2298
1935	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2299	C<$flags> can be a combination of
1936	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2300	C<IO::AIO::MAP_SHARED> or
1937	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2301	C<IO::AIO::MAP_PRIVATE>,
		2302	or a number of system-specific flags (when not available, the are C<0>):
1938	(which is set to C<MAP_ANON> if your system only provides this	2303	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1939	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2304	C<IO::AIO::MAP_LOCKED>,
1940	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2305	C<IO::AIO::MAP_NORESERVE>,
		2306	C<IO::AIO::MAP_POPULATE>,
1941	C<IO::AIO::MAP_NONBLOCK>	2307	C<IO::AIO::MAP_NONBLOCK>,
		2308	C<IO::AIO::MAP_FIXED>,
		2309	C<IO::AIO::MAP_GROWSDOWN>,
		2310	C<IO::AIO::MAP_32BIT>,
		2311	C<IO::AIO::MAP_HUGETLB> or
		2312	C<IO::AIO::MAP_STACK>.
1942		2313
1943	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2314	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1944		2315
1945	C<$offset> is the offset from the start of the file - it generally must be	2316	C<$offset> is the offset from the start of the file - it generally must be
1946	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2317	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1959	my $fast_md5 = md5 $data;	2330	my $fast_md5 = md5 $data;
1960		2331
1961	=item IO::AIO::munmap $scalar	2332	=item IO::AIO::munmap $scalar
1962		2333
1963	Removes a previous mmap and undefines the C<$scalar>.	2334	Removes a previous mmap and undefines the C<$scalar>.
		2335
		2336	=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
		2337
		2338	Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
		2339	been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
		2340	C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
		2341
		2342	Returns true if successful, and false otherwise. If the underlying mmapped
		2343	region has changed address, then the true value has the numerical value
		2344	C<1>, otherwise it has the numerical value C<0>:
		2345
		2346	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		2347	or die "mremap: $!";
		2348
		2349	if ($success*1) {
		2350	warn "scalar has chanegd address in memory\n";
		2351	}
		2352
		2353	C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
		2354	implemented, but not supported and might go away in a future version.
		2355
		2356	On systems where this call is not supported or is not emulated, this call
		2357	returns falls and sets C<$!> to C<ENOSYS>.
		2358
		2359	=item IO::AIO::mlockall $flags
		2360
		2361	Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
		2362	but is blocking.
1964		2363
1965	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef	2364	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1966		2365
1967	Calls the C<munlock> function, undoing the effects of a previous	2366	Calls the C<munlock> function, undoing the effects of a previous
1968	C<aio_mlock> call (see its description for details).	2367	C<aio_mlock> call (see its description for details).
…		…
1989		2388
1990	See the C<splice(2)> manpage for details.	2389	See the C<splice(2)> manpage for details.
1991		2390
1992	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags	2391	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
1993		2392
1994	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the	2393	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
1995	description for C<IO::AIO::splice> above for details.	2394	description for C<IO::AIO::splice> above for details.
		2395
		2396	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2397
		2398	Attempts to query or change the pipe buffer size. Obviously works only
		2399	on pipes, and currently works only on GNU/Linux systems, and fails with
		2400	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2401	size on other systems, drop me a note.
		2402
		2403	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2404
		2405	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2406	C<$flags> is missing or C<0>, then this should be the same as a call to
		2407	perl's built-in C<pipe> function and create a new pipe, and works on
		2408	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2409	(..., 4096, O_BINARY)>.
		2410
		2411	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2412	the given flags (Linux 2.6.27, glibc 2.9).
		2413
		2414	On success, the read and write file handles are returned.
		2415
		2416	On error, nothing will be returned. If the pipe2 syscall is missing and
		2417	C<$flags> is non-zero, fails with C<ENOSYS>.
		2418
		2419	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2420	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2421	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2422
		2423	Example: create a pipe race-free w.r.t. threads and fork:
		2424
		2425	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2426	or die "pipe2: $!\n";
		2427
		2428	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2429
		2430	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2431	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2432
		2433	On success, the new eventfd filehandle is returned, otherwise returns
		2434	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2435
		2436	Please refer to L<eventfd(2)> for more info on this call.
		2437
		2438	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2439	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2440
		2441	Example: create a new eventfd filehandle:
		2442
		2443	$fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
		2444	or die "eventfd: $!\n";
		2445
		2446	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2447
		2448	This is a direct interface to the Linux L<timerfd_create(2)> system call. The
		2449	(unhelpful) default for C<$flags> is C<0>.
		2450
		2451	On success, the new timerfd filehandle is returned, otherwise returns
		2452	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2453
		2454	Please refer to L<timerfd_create(2)> for more info on this call.
		2455
		2456	The following C<$clockid> values are
		2457	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2458	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2459	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2460	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2461
		2462	The following C<$flags> values are available (Linux
		2463	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2464
		2465	Example: create a new timerfd and set it to one-second repeated alarms,
		2466	then wait for two alarms:
		2467
		2468	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2469	or die "timerfd_create: $!\n";
		2470
		2471	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2472	or die "timerfd_settime: $!\n";
		2473
		2474	for (1..2) {
		2475	8 == sysread $fh, my $buf, 8
		2476	or die "timerfd read failure\n";
		2477
		2478	printf "number of expirations (likely 1): %d\n",
		2479	unpack "Q", $buf;
		2480	}
		2481
		2482	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2483
		2484	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2485	call. Please refer to its manpage for more info on this call.
		2486
		2487	The new itimerspec is specified using two (possibly fractional) second
		2488	values, C<$new_interval> and C<$new_value>).
		2489
		2490	On success, the current interval and value are returned (as per
		2491	C<timerfd_gettime>). On failure, the empty list is returned.
		2492
		2493	The following C<$flags> values are
		2494	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2495	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2496
		2497	See C<IO::AIO::timerfd_create> for a full example.
		2498
		2499	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2500
		2501	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2502	call. Please refer to its manpage for more info on this call.
		2503
		2504	On success, returns the current values of interval and value for the given
		2505	timerfd (as potentially fractional second values). On failure, the empty
		2506	list is returned.
1996		2507
1997	=back	2508	=back
1998		2509
1999	=cut	2510	=cut
2000		2511
…		…
2066	the process will result in undefined behaviour. Calling it at any time	2577	the process will result in undefined behaviour. Calling it at any time
2067	will also result in any undefined (by POSIX) behaviour.	2578	will also result in any undefined (by POSIX) behaviour.
2068		2579
2069	=back	2580	=back
2070		2581
		2582	=head2 LINUX-SPECIFIC CALLS
		2583
		2584	When a call is documented as "linux-specific" then this means it
		2585	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2586	availability and compatibility of such calls regardless of the platform
		2587	it is compiled on, so platforms such as FreeBSD which often implement
		2588	these calls will work. When in doubt, call them and see if they fail wth
		2589	C<ENOSYS>.
		2590
2071	=head2 MEMORY USAGE	2591	=head2 MEMORY USAGE
2072		2592
2073	Per-request usage:	2593	Per-request usage:
2074		2594
2075	Each aio request uses - depending on your architecture - around 100-200	2595	Each aio request uses - depending on your architecture - around 100-200
…		…
2087	temporary buffers, and each thread requires a stack and other data	2607	temporary buffers, and each thread requires a stack and other data
2088	structures (usually around 16k-128k, depending on the OS).	2608	structures (usually around 16k-128k, depending on the OS).
2089		2609
2090	=head1 KNOWN BUGS	2610	=head1 KNOWN BUGS
2091		2611
2092	Known bugs will be fixed in the next release.	2612	Known bugs will be fixed in the next release :)
		2613
		2614	=head1 KNOWN ISSUES
		2615
		2616	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2617	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2618	non-created hash slots or other scalars I didn't think of. It's best to
		2619	avoid such and either use scalar variables or making sure that the scalar
		2620	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2621
		2622	I am not sure anything can be done about this, so this is considered a
		2623	known issue, rather than a bug.
2093		2624
2094	=head1 SEE ALSO	2625	=head1 SEE ALSO
2095		2626
2096	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2627	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2097	more natural syntax.	2628	more natural syntax.

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.228 by root, Sun Jun 17 17:07:25 2012 UTC vs. Revision 1.300 by root, Sun Mar 10 12:11:46 2019 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.228 by root, Sun Jun 17 17:07:25 2012 UTC vs.
Revision 1.300 by root, Sun Mar 10 12:11:46 2019 UTC