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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.225 by root, Tue Apr 10 05:01:33 2012 UTC vs.
Revision 1.298 by root, Thu Nov 29 21:48:44 2018 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 = 4.6;
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
		288	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		289	IO::AIO::munmap $scalar
		290	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
277	IO::AIO::madvise $scalar, $offset, $length, $advice	291	IO::AIO::madvise $scalar, $offset, $length, $advice
278	IO::AIO::mprotect $scalar, $offset, $length, $protect	292	IO::AIO::mprotect $scalar, $offset, $length, $protect
279	IO::AIO::munlock $scalar, $offset = 0, $length = undef	293	IO::AIO::munlock $scalar, $offset = 0, $length = undef
280	IO::AIO::munlockall	294	IO::AIO::munlockall
281		295
…		…
358		372
359		373
360	=item aio_open $pathname, $flags, $mode, $callback->($fh)	374	=item aio_open $pathname, $flags, $mode, $callback->($fh)
361		375
362	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
363	created filehandle for the file.	377	created filehandle for the file (or C<undef> in case of an error).
364		378
365	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,
366	for an explanation.	380	for an explanation.
367		381
368	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
…		…
391	following POSIX and non-POSIX constants are available (missing ones on	405	following POSIX and non-POSIX constants are available (missing ones on
392	your system are, as usual, C<0>):	406	your system are, as usual, C<0>):
393		407
394	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>,
395	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>,
396	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>.
397		411
398		412
399	=item aio_close $fh, $callback->($status)	413	=item aio_close $fh, $callback->($status)
400		414
401	Asynchronously close a file and call the callback with the result	415	Asynchronously close a file and call the callback with the result
…		…
436	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	450	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
437		451
438	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	452	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
439		453
440	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
441	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
442	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
443	error, just like the syscall).	457	error, just like the syscall).
444		458
445	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
446	offset plus the actual number of bytes read.	460	offset plus the actual number of bytes read.
447		461
…		…
505	As native sendfile syscalls (as practically any non-POSIX interface hacked	519	As native sendfile syscalls (as practically any non-POSIX interface hacked
506	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
507	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
508	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,
509	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> -
510	fewre bytes than expected might have been transferred.	524	fewer bytes than expected might have been transferred.
511		525
512		526
513	=item aio_readahead $fh,$offset,$length, $callback->($retval)	527	=item aio_readahead $fh,$offset,$length, $callback->($retval)
514		528
515	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
…		…
519	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
520	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
521	(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
522	file. The current file offset of the file is left unchanged.	536	file. The current file offset of the file is left unchanged.
523		537
524	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
525	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.
526		540
527		541
528	=item aio_stat $fh_or_path, $callback->($status)	542	=item aio_stat $fh_or_path, $callback->($status)
529		543
530	=item aio_lstat $fh, $callback->($status)	544	=item aio_lstat $fh, $callback->($status)
531		545
532	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
533	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
534	or C<-s _> etc...	548	using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
		549	and C<-T>).
535		550
536	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,
537	for an explanation.	552	for an explanation.
538		553
539	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
…		…
546	behaviour).	561	behaviour).
547		562
548	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>,
549	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>,
550	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>.
551		569
552	Example: Print the length of F</etc/passwd>:	570	Example: Print the length of F</etc/passwd>:
553		571
554	aio_stat "/etc/passwd", sub {	572	aio_stat "/etc/passwd", sub {
555	$_[0] and die "stat failed: $!";	573	$_[0] and die "stat failed: $!";
…		…
599	namemax => 255,	617	namemax => 255,
600	frsize => 1024,	618	frsize => 1024,
601	fsid => 1810	619	fsid => 1810
602	}	620	}
603		621
604
605	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	622	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
606		623
607	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
608	and $mtime being undef). Fractional times are supported if the underlying	625	and $mtime being undef). Fractional times are supported if the underlying
609	syscalls support them.	626	syscalls support them.
610		627
611	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,
612	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)
613	otherwise returns ENOSYS, so this is not portable.	630	or futimes(2) if available, otherwise returns ENOSYS, so this is not
		631	portable.
614		632
615	Examples:	633	Examples:
616		634
617	# set atime and mtime to current time (basically touch(1)):	635	# set atime and mtime to current time (basically touch(1)):
618	aio_utime "path", undef, undef;	636	aio_utime "path", undef, undef;
…		…
636	=item aio_truncate $fh_or_path, $offset, $callback->($status)	654	=item aio_truncate $fh_or_path, $offset, $callback->($status)
637		655
638	Works like truncate(2) or ftruncate(2).	656	Works like truncate(2) or ftruncate(2).
639		657
640		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
641	=item aio_chmod $fh_or_path, $mode, $callback->($status)	681	=item aio_chmod $fh_or_path, $mode, $callback->($status)
642		682
643	Works like perl's C<chmod> function.	683	Works like perl's C<chmod> function.
644		684
645		685
…		…
682		722
683		723
684	=item aio_realpath $pathname, $callback->($path)	724	=item aio_realpath $pathname, $callback->($path)
685		725
686	Asynchronously make the path absolute and resolve any symlinks in	726	Asynchronously make the path absolute and resolve any symlinks in
687	C<$path>. The resulting path only consists of directories (Same as	727	C<$path>. The resulting path only consists of directories (same as
688	L<Cwd::realpath>).	728	L<Cwd::realpath>).
689		729
690	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
691	directory by passing it a path of F<.> (a single dot).	731	directory by passing it a path of F<.> (a single dot).
692		732
693		733
694	=item aio_rename $srcpath, $dstpath, $callback->($status)	734	=item aio_rename $srcpath, $dstpath, $callback->($status)
695		735
696	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
697	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>.
698		758
699		759
700	=item aio_mkdir $pathname, $mode, $callback->($status)	760	=item aio_mkdir $pathname, $mode, $callback->($status)
701		761
702	Asynchronously mkdir (create) a directory and call the callback with	762	Asynchronously mkdir (create) a directory and call the callback with
…		…
707	=item aio_rmdir $pathname, $callback->($status)	767	=item aio_rmdir $pathname, $callback->($status)
708		768
709	Asynchronously rmdir (delete) a directory and call the callback with the	769	Asynchronously rmdir (delete) a directory and call the callback with the
710	result code.	770	result code.
711		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
712		776
713	=item aio_readdir $pathname, $callback->($entries)	777	=item aio_readdir $pathname, $callback->($entries)
714		778
715	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
716	directory (i.e. opendir + readdir + closedir). The entries will not be	780	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
731		795
732	=over 4	796	=over 4
733		797
734	=item IO::AIO::READDIR_DENTS	798	=item IO::AIO::READDIR_DENTS
735		799
736	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
737	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
738	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	802	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
739	entry in more detail.	803	single directory entry in more detail:
740		804
741	C<$name> is the name of the entry.	805	C<$name> is the name of the entry.
742		806
743	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	807	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
744		808
745	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	809	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
746	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	810	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
747	C<IO::AIO::DT_WHT>.	811	C<IO::AIO::DT_WHT>.
748		812
749	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	813	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
750	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	814	to know, you have to run stat yourself. Also, for speed/memory reasons,
751	scalars are read-only: you can not modify them.	815	the C<$type> scalars are read-only: you must not modify them.
752		816
753	C<$inode> is the inode number (which might not be exact on systems with 64	817	C<$inode> is the inode number (which might not be exact on systems with 64
754	bit inode numbers and 32 bit perls). This field has unspecified content on	818	bit inode numbers and 32 bit perls). This field has unspecified content on
755	systems that do not deliver the inode information.	819	systems that do not deliver the inode information.
756		820
…		…
767	short names are tried first.	831	short names are tried first.
768		832
769	=item IO::AIO::READDIR_STAT_ORDER	833	=item IO::AIO::READDIR_STAT_ORDER
770		834
771	When this flag is set, then the names will be returned in an order	835	When this flag is set, then the names will be returned in an order
772	suitable for stat()'ing each one. That is, when you plan to stat()	836	suitable for stat()'ing each one. That is, when you plan to stat() most or
773	all files in the given directory, then the returned order will likely	837	all files in the given directory, then the returned order will likely be
774	be fastest.	838	faster.
775		839
776	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	840	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
777	the likely dirs come first, resulting in a less optimal stat order.	841	then the likely dirs come first, resulting in a less optimal stat order
		842	for stat'ing all entries, but likely a more optimal order for finding
		843	subdirectories.
778		844
779	=item IO::AIO::READDIR_FOUND_UNKNOWN	845	=item IO::AIO::READDIR_FOUND_UNKNOWN
780		846
781	This flag should not be set when calling C<aio_readdirx>. Instead, it	847	This flag should not be set when calling C<aio_readdirx>. Instead, it
782	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	848	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
784	C<$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.
785		851
786	=back	852	=back
787		853
788		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
789	=item aio_load $pathname, $data, $callback->($status)	884	=item aio_load $pathname, $data, $callback->($status)
790		885
791	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
792	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.
793		890
794	=cut	891	=cut
795		892
796	sub aio_load($$;$) {	893	sub aio_load($$;$) {
797	my ($path, undef, $cb) = @_;	894	my ($path, undef, $cb) = @_;
…		…
817	=item aio_copy $srcpath, $dstpath, $callback->($status)	914	=item aio_copy $srcpath, $dstpath, $callback->($status)
818		915
819	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
820	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
821	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.
822		921
823	This is a composite request that creates the destination file with	922	This is a composite request that creates the destination file with
824	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
825	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	924	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
826	uid/gid, in that order.	925	uid/gid, in that order.
…		…
936	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
937	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
938	names, directories you can recurse into (directories), and ones you cannot	1037	names, directories you can recurse into (directories), and ones you cannot
939	recurse into (everything else, including symlinks to directories).	1038	recurse into (everything else, including symlinks to directories).
940		1039
941	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.
942	C<$maxreq> specifies the maximum number of outstanding aio requests that	1041	C<$maxreq> specifies the maximum number of outstanding aio requests that
943	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
944	will be chosen (currently 4).	1043	will be chosen (currently 4).
945		1044
946	On error, the callback is called without arguments, otherwise it receives	1045	On error, the callback is called without arguments, otherwise it receives
…		…
1080	}	1179	}
1081		1180
1082	=item aio_rmtree $pathname, $callback->($status)	1181	=item aio_rmtree $pathname, $callback->($status)
1083		1182
1084	Delete a directory tree starting (and including) C<$path>, return the	1183	Delete a directory tree starting (and including) C<$path>, return the
1085	status of the final C<rmdir> only. This is a composite request that	1184	status of the final C<rmdir> only. This is a composite request that
1086	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1185	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1087	everything else.	1186	everything else.
1088		1187
1089	=cut	1188	=cut
1090		1189
…		…
1111	add $grp $dirgrp;	1210	add $grp $dirgrp;
1112	};	1211	};
1113		1212
1114	$grp	1213	$grp
1115	}	1214	}
		1215
		1216	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1217
		1218	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1219
		1220	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1221	they execute asynchronously and pass the return value to the callback.
		1222
		1223	Both calls can be used for a lot of things, some of which make more sense
		1224	to run asynchronously in their own thread, while some others make less
		1225	sense. For example, calls that block waiting for external events, such
		1226	as locking, will also lock down an I/O thread while it is waiting, which
		1227	can deadlock the whole I/O system. At the same time, there might be no
		1228	alternative to using a thread to wait.
		1229
		1230	So in general, you should only use these calls for things that do
		1231	(filesystem) I/O, not for things that wait for other events (network,
		1232	other processes), although if you are careful and know what you are doing,
		1233	you still can.
		1234
		1235	The following constants are available (missing ones are, as usual C<0>):
		1236
		1237	C<F_DUPFD_CLOEXEC>,
		1238
		1239	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1240
		1241	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1242
		1243	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1244	C<FS_IOC_FIEMAP>.
		1245
		1246	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1247	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1248
		1249	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1250	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1251	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1252	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1253	C<FS_FL_USER_MODIFIABLE>.
		1254
		1255	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1256	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1257	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1258	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1116		1259
1117	=item aio_sync $callback->($status)	1260	=item aio_sync $callback->($status)
1118		1261
1119	Asynchronously call sync and call the callback when finished.	1262	Asynchronously call sync and call the callback when finished.
1120		1263
…		…
1189	};	1332	};
1190		1333
1191	$grp	1334	$grp
1192	}	1335	}
1193		1336
1194	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1337	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1195		1338
1196	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1339	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1197	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1340	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1198	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1341	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1199	scalar must only be modified in-place while an aio operation is pending on	1342	scalar must only be modified in-place while an aio operation is pending on
…		…
1201		1344
1202	It calls the C<msync> function of your OS, if available, with the memory	1345	It calls the C<msync> function of your OS, if available, with the memory
1203	area starting at C<$offset> in the string and ending C<$length> bytes	1346	area starting at C<$offset> in the string and ending C<$length> bytes
1204	later. If C<$length> is negative, counts from the end, and if C<$length>	1347	later. If C<$length> is negative, counts from the end, and if C<$length>
1205	is C<undef>, then it goes till the end of the string. The flags can be	1348	is C<undef>, then it goes till the end of the string. The flags can be
1206	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1349	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1207	C<IO::AIO::MS_SYNC>.	1350	C<IO::AIO::MS_INVALIDATE>.
1208		1351
1209	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1352	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1210		1353
1211	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1354	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1212	scalars.	1355	scalars.
1213		1356
1214	It touches (reads or writes) all memory pages in the specified	1357	It touches (reads or writes) all memory pages in the specified
1215	range inside the scalar. All caveats and parameters are the same	1358	range inside the scalar. All caveats and parameters are the same
1216	as for C<aio_msync>, above, except for flags, which must be either	1359	as for C<aio_msync>, above, except for flags, which must be either
1217	C<0> (which reads all pages and ensures they are instantiated) or	1360	C<0> (which reads all pages and ensures they are instantiated) or
1218	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1361	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1219	writing an octet from it, which dirties the page).	1362	writing an octet from it, which dirties the page).
1220		1363
1221	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1364	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1222		1365
1223	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1366	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1242	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;	1385	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1243	aio_mlock $data; # mlock in background	1386	aio_mlock $data; # mlock in background
1244		1387
1245	=item aio_mlockall $flags, $callback->($status)	1388	=item aio_mlockall $flags, $callback->($status)
1246		1389
1247	Calls the C<mlockall> function with the given C<$flags> (a combination of	1390	Calls the C<mlockall> function with the given C<$flags> (a
1248	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).	1391	combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
		1392	C<IO::AIO::MCL_ONFAULT>).
1249		1393
1250	On systems that do not implement C<mlockall>, this function returns C<-1>	1394	On systems that do not implement C<mlockall>, this function returns C<-1>
1251	and sets errno to C<ENOSYS>.	1395	and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
		1396	by the system result in a return value of C<-1> with errno being set to
		1397	C<EINVAL>.
1252		1398
1253	Note that the corresponding C<munlockall> is synchronous and is	1399	Note that the corresponding C<munlockall> is synchronous and is
1254	documented under L<MISCELLANEOUS FUNCTIONS>.	1400	documented under L<MISCELLANEOUS FUNCTIONS>.
1255		1401
1256	Example: asynchronously lock all current and future pages into memory.	1402	Example: asynchronously lock all current and future pages into memory.
1257		1403
1258	aio_mlockall IO::AIO::MCL_FUTURE;	1404	aio_mlockall IO::AIO::MCL_FUTURE;
1259		1405
1260	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)	1406	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1261		1407
1262	Queries the extents of the given file (by calling the Linux FIEMAP ioctl,	1408	Queries the extents of the given file (by calling the Linux C<FIEMAP>
1263	see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the	1409	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1264	C<ioctl> is not available on your OS, then this rquiest will fail with	1410	the ioctl is not available on your OS, then this request will fail with
1265	C<ENOSYS>.	1411	C<ENOSYS>.
1266		1412
1267	C<$start> is the starting offset to query extents for, C<$length> is the	1413	C<$start> is the starting offset to query extents for, C<$length> is the
1268	size of the range to query - if it is C<undef>, then the whole file will	1414	size of the range to query - if it is C<undef>, then the whole file will
1269	be queried.	1415	be queried.
…		…
1272	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also	1418	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1273	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query	1419	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1274	the data portion.	1420	the data portion.
1275		1421
1276	C<$count> is the maximum number of extent records to return. If it is	1422	C<$count> is the maximum number of extent records to return. If it is
1277	C<undef>, then IO::AIO queries all extents of the file. As a very special	1423	C<undef>, then IO::AIO queries all extents of the range. As a very special
1278	case, if it is C<0>, then the callback receives the number of extents	1424	case, if it is C<0>, then the callback receives the number of extents
1279	instead of the extents themselves.	1425	instead of the extents themselves (which is unreliable, see below).
1280		1426
1281	If an error occurs, the callback receives no arguments. The special	1427	If an error occurs, the callback receives no arguments. The special
1282	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.	1428	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1283		1429
1284	Otherwise, the callback receives an array reference with extent	1430	Otherwise, the callback receives an array reference with extent
…		…
1286	following members:	1432	following members:
1287		1433
1288	[$logical, $physical, $length, $flags]	1434	[$logical, $physical, $length, $flags]
1289		1435
1290	Flags is any combination of the following flag values (typically either C<0>	1436	Flags is any combination of the following flag values (typically either C<0>
1291	or C<IO::AIO::FIEMAP_EXTENT_LAST>):	1437	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1292		1438
1293	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,	1439	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1294	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,	1440	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1295	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,	1441	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1296	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,	1442	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1297	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or	1443	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1298	C<IO::AIO::FIEMAP_EXTENT_SHARED>.	1444	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1299		1445
		1446	At the time of this writing (Linux 3.2), this request is unreliable unless
		1447	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1448	it to return all extents of a range for files with a large number of
		1449	extents. The code (only) works around all these issues if C<$count> is
		1450	C<undef>.
		1451
1300	=item aio_group $callback->(...)	1452	=item aio_group $callback->(...)
1301		1453
1302	This is a very special aio request: Instead of doing something, it is a	1454	This is a very special aio request: Instead of doing something, it is a
1303	container for other aio requests, which is useful if you want to bundle	1455	container for other aio requests, which is useful if you want to bundle
1304	many requests into a single, composite, request with a definite callback	1456	many requests into a single, composite, request with a definite callback
…		…
1387	aio_stat [$etcdir, "passwd"], sub {	1539	aio_stat [$etcdir, "passwd"], sub {
1388	# yay	1540	# yay
1389	};	1541	};
1390	};	1542	};
1391		1543
1392	That C<aio_wd> is a request and not a normal function shows that creating	1544	The fact that C<aio_wd> is a request and not a normal function shows that
1393	an IO::AIO::WD object is itself a potentially blocking operation, which is	1545	creating an IO::AIO::WD object is itself a potentially blocking operation,
1394	why it is done asynchronously.	1546	which is why it is done asynchronously.
1395		1547
1396	To stat the directory obtained with C<aio_wd> above, one could write	1548	To stat the directory obtained with C<aio_wd> above, one could write
1397	either of the following three request calls:	1549	either of the following three request calls:
1398		1550
1399	aio_lstat "/etc" , sub { ... # pathname as normal string	1551	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1416	There are some caveats: when directories get renamed (or deleted), the	1568	There are some caveats: when directories get renamed (or deleted), the
1417	pathname string doesn't change, so will point to the new directory (or	1569	pathname string doesn't change, so will point to the new directory (or
1418	nowhere at all), while the directory fd, if available on the system,	1570	nowhere at all), while the directory fd, if available on the system,
1419	will still point to the original directory. Most functions accepting a	1571	will still point to the original directory. Most functions accepting a
1420	pathname will use the directory fd on newer systems, and the string on	1572	pathname will use the directory fd on newer systems, and the string on
1421	older systems. Some functions (such as realpath) will always rely on the	1573	older systems. Some functions (such as C<aio_realpath>) will always rely on
1422	string form of the pathname.	1574	the string form of the pathname.
1423		1575
1424	So this fucntionality is mainly useful to get some protection against	1576	So this functionality is mainly useful to get some protection against
1425	C<chdir>, to easily get an absolute path out of a relative path for future	1577	C<chdir>, to easily get an absolute path out of a relative path for future
1426	reference, and to speed up doing many operations in the same directory	1578	reference, and to speed up doing many operations in the same directory
1427	(e.g. when stat'ing all files in a directory).	1579	(e.g. when stat'ing all files in a directory).
1428		1580
1429	The following functions implement this working directory abstraction:	1581	The following functions implement this working directory abstraction:
…		…
1442	passing C<undef> as working directory component of a pathname fails the	1594	passing C<undef> as working directory component of a pathname fails the
1443	request with C<ENOENT>, there is often no need for error checking in the	1595	request with C<ENOENT>, there is often no need for error checking in the
1444	C<aio_wd> callback, as future requests using the value will fail in the	1596	C<aio_wd> callback, as future requests using the value will fail in the
1445	expected way.	1597	expected way.
1446		1598
1447	If this call isn't available because your OS lacks it or it couldn't be
1448	detected, it will be emulated by calling C<fsync> instead.
1449
1450	=item IO::AIO::CWD	1599	=item IO::AIO::CWD
1451		1600
1452	This is a compiletime constant (object) that represents the process	1601	This is a compiletime constant (object) that represents the process
1453	current working directory.	1602	current working directory.
1454		1603
1455	Specifying this object as working directory object for a pathname is as	1604	Specifying this object as working directory object for a pathname is as if
1456	if the pathname would be specified directly, without a directory object,	1605	the pathname would be specified directly, without a directory object. For
1457	e.g., these calls are functionally identical:	1606	example, these calls are functionally identical:
1458		1607
1459	aio_stat "somefile", sub { ... };	1608	aio_stat "somefile", sub { ... };
1460	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1609	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1461		1610
1462	=back	1611	=back
1463		1612
		1613	To recover the path associated with an IO::AIO::WD object, you can use
		1614	C<aio_realpath>:
		1615
		1616	aio_realpath $wd, sub {
		1617	warn "path is $_[0]\n";
		1618	};
		1619
		1620	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1621	sometimes, fall back to using an absolue path.
1464		1622
1465	=head2 IO::AIO::REQ CLASS	1623	=head2 IO::AIO::REQ CLASS
1466		1624
1467	All non-aggregate C<aio_*> functions return an object of this class when	1625	All non-aggregate C<aio_*> functions return an object of this class when
1468	called in non-void context.	1626	called in non-void context.
…		…
1629	The default value for the limit is C<0>, but note that setting a feeder	1787	The default value for the limit is C<0>, but note that setting a feeder
1630	automatically bumps it up to C<2>.	1788	automatically bumps it up to C<2>.
1631		1789
1632	=back	1790	=back
1633		1791
		1792
1634	=head2 SUPPORT FUNCTIONS	1793	=head2 SUPPORT FUNCTIONS
1635		1794
1636	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1795	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1637		1796
1638	=over 4	1797	=over 4
…		…
1646		1805
1647	See C<poll_cb> for an example.	1806	See C<poll_cb> for an example.
1648		1807
1649	=item IO::AIO::poll_cb	1808	=item IO::AIO::poll_cb
1650		1809
1651	Process some outstanding events on the result pipe. You have to call	1810	Process some requests that have reached the result phase (i.e. they have
		1811	been executed but the results are not yet reported). You have to call
		1812	this "regularly" to finish outstanding requests.
		1813
1652	this regularly. Returns C<0> if all events could be processed (or there	1814	Returns C<0> if all events could be processed (or there were no
1653	were no events to process), or C<-1> if it returned earlier for whatever	1815	events to process), or C<-1> if it returned earlier for whatever
1654	reason. Returns immediately when no events are outstanding. The amount of	1816	reason. Returns immediately when no events are outstanding. The amount
1655	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1817	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1656	C<IO::AIO::max_poll_time>.	1818	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1657		1819
1658	If not all requests were processed for whatever reason, the filehandle	1820	If not all requests were processed for whatever reason, the poll file
1659	will still be ready when C<poll_cb> returns, so normally you don't have to	1821	descriptor will still be ready when C<poll_cb> returns, so normally you
1660	do anything special to have it called later.	1822	don't have to do anything special to have it called later.
1661		1823
1662	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1824	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1663	ready, it can be beneficial to call this function from loops which submit	1825	ready, it can be beneficial to call this function from loops which submit
1664	a lot of requests, to make sure the results get processed when they become	1826	a lot of requests, to make sure the results get processed when they become
1665	available and not just when the loop is finished and the event loop takes	1827	available and not just when the loop is finished and the event loop takes
…		…
1674	poll => 'r', async => 1,	1836	poll => 'r', async => 1,
1675	cb => \&IO::AIO::poll_cb);	1837	cb => \&IO::AIO::poll_cb);
1676		1838
1677	=item IO::AIO::poll_wait	1839	=item IO::AIO::poll_wait
1678		1840
1679	If there are any outstanding requests and none of them in the result	1841	Wait until either at least one request is in the result phase or no
1680	phase, wait till the result filehandle becomes ready for reading (simply	1842	requests are outstanding anymore.
1681	does a C<select> on the filehandle. This is useful if you want to	1843
1682	synchronously wait for some requests to finish).	1844	This is useful if you want to synchronously wait for some requests to
		1845	become ready, without actually handling them.
1683		1846
1684	See C<nreqs> for an example.	1847	See C<nreqs> for an example.
1685		1848
1686	=item IO::AIO::poll	1849	=item IO::AIO::poll
1687		1850
…		…
1698		1861
1699	Strictly equivalent to:	1862	Strictly equivalent to:
1700		1863
1701	IO::AIO::poll_wait, IO::AIO::poll_cb	1864	IO::AIO::poll_wait, IO::AIO::poll_cb
1702	while IO::AIO::nreqs;	1865	while IO::AIO::nreqs;
		1866
		1867	This function can be useful at program aborts, to make sure outstanding
		1868	I/O has been done (C<IO::AIO> uses an C<END> block which already calls
		1869	this function on normal exits), or when you are merely using C<IO::AIO>
		1870	for its more advanced functions, rather than for async I/O, e.g.:
		1871
		1872	my ($dirs, $nondirs);
		1873	IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
		1874	IO::AIO::flush;
		1875	# $dirs, $nondirs are now set
1703		1876
1704	=item IO::AIO::max_poll_reqs $nreqs	1877	=item IO::AIO::max_poll_reqs $nreqs
1705		1878
1706	=item IO::AIO::max_poll_time $seconds	1879	=item IO::AIO::max_poll_time $seconds
1707		1880
…		…
1734	poll => 'r', nice => 1,	1907	poll => 'r', nice => 1,
1735	cb => &IO::AIO::poll_cb);	1908	cb => &IO::AIO::poll_cb);
1736		1909
1737	=back	1910	=back
1738		1911
		1912
1739	=head3 CONTROLLING THE NUMBER OF THREADS	1913	=head3 CONTROLLING THE NUMBER OF THREADS
1740		1914
1741	=over	1915	=over
1742		1916
1743	=item IO::AIO::min_parallel $nthreads	1917	=item IO::AIO::min_parallel $nthreads
…		…
1808		1982
1809	This is a very bad function to use in interactive programs because it	1983	This is a very bad function to use in interactive programs because it
1810	blocks, and a bad way to reduce concurrency because it is inexact: Better	1984	blocks, and a bad way to reduce concurrency because it is inexact: Better
1811	use an C<aio_group> together with a feed callback.	1985	use an C<aio_group> together with a feed callback.
1812		1986
1813	It's main use is in scripts without an event loop - when you want to stat	1987	Its main use is in scripts without an event loop - when you want to stat
1814	a lot of files, you can write somehting like this:	1988	a lot of files, you can write something like this:
1815		1989
1816	IO::AIO::max_outstanding 32;	1990	IO::AIO::max_outstanding 32;
1817		1991
1818	for my $path (...) {	1992	for my $path (...) {
1819	aio_stat $path , ...;	1993	aio_stat $path , ...;
…		…
1830	The default value for C<max_outstanding> is very large, so there is no	2004	The default value for C<max_outstanding> is very large, so there is no
1831	practical limit on the number of outstanding requests.	2005	practical limit on the number of outstanding requests.
1832		2006
1833	=back	2007	=back
1834		2008
		2009
1835	=head3 STATISTICAL INFORMATION	2010	=head3 STATISTICAL INFORMATION
1836		2011
1837	=over	2012	=over
1838		2013
1839	=item IO::AIO::nreqs	2014	=item IO::AIO::nreqs
…		…
1856	Returns the number of requests currently in the pending state (executed,	2031	Returns the number of requests currently in the pending state (executed,
1857	but not yet processed by poll_cb).	2032	but not yet processed by poll_cb).
1858		2033
1859	=back	2034	=back
1860		2035
		2036
		2037	=head3 SUBSECOND STAT TIME ACCESS
		2038
		2039	Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
		2040	generally find access/modification and change times with subsecond time
		2041	accuracy of the system supports it, but perl's built-in functions only
		2042	return the integer part.
		2043
		2044	The following functions return the timestamps of the most recent
		2045	stat with subsecond precision on most systems and work both after
		2046	C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
		2047	value is only meaningful after a successful C<stat>/C<lstat> call, or
		2048	during/after a successful C<aio_stat>/C<aio_lstat> callback.
		2049
		2050	This is similar to the L<Time::HiRes> C<stat> functions, but can return
		2051	full resolution without rounding and work with standard perl C<stat>,
		2052	alleviating the need to call the special C<Time::HiRes> functions, which
		2053	do not act like their perl counterparts.
		2054
		2055	On operating systems or file systems where subsecond time resolution is
		2056	not supported or could not be detected, a fractional part of C<0> is
		2057	returned, so it is always safe to call these functions.
		2058
		2059	=over 4
		2060
		2061	=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
		2062
		2063	Return the access, modication, change or birth time, respectively,
		2064	including fractional part. Due to the limited precision of floating point,
		2065	the accuracy on most platforms is only a bit better than milliseconds
		2066	for times around now - see the I<nsec> function family, below, for full
		2067	accuracy.
		2068
		2069	File birth time is only available when the OS and perl support it (on
		2070	FreeBSD and NetBSD at the time of this writing, although support is
		2071	adaptive, so if your OS/perl gains support, IO::AIO can take avdantage of
		2072	it). On systems where it isn't available, C<0> is currently returned, but
		2073	this might change to C<undef> in a future version.
		2074
		2075	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
		2076
		2077	Returns access, modification, change and birth time all in one go, and
		2078	maybe more times in the future version.
		2079
		2080	=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
		2081
		2082	Return the fractional access, modifcation, change or birth time, in nanoseconds,
		2083	as an integer in the range C<0> to C<999999999>.
		2084
		2085	Note that no accessors are provided for access, modification and
		2086	change times - you need to get those from C<stat _> if required (C<int
		2087	IO::AIO::st_atime> and so on will I<not> generally give you the correct
		2088	value).
		2089
		2090	=item $seconds = IO::AIO::st_btimesec
		2091
		2092	The (integral) seconds part of the file birth time, if available.
		2093
		2094	=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
		2095
		2096	Like the functions above, but returns all four times in one go (and maybe
		2097	more in future versions).
		2098
		2099	=item $counter = IO::AIO::st_gen
		2100
		2101	Returns the generation counter (in practice this is just a random number)
		2102	of the file. This is only available on platforms which have this member in
		2103	their C<struct stat> (most BSDs at the time of this writing) and generally
		2104	only to the root usert. If unsupported, C<0> is returned, but this might
		2105	change to C<undef> in a future version.
		2106
		2107	=back
		2108
		2109	Example: print the high resolution modification time of F</etc>, using
		2110	C<stat>, and C<IO::AIO::aio_stat>.
		2111
		2112	if (stat "/etc") {
		2113	printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
		2114	}
		2115
		2116	IO::AIO::aio_stat "/etc", sub {
		2117	$_[0]
		2118	and return;
		2119
		2120	printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
		2121	};
		2122
		2123	IO::AIO::flush;
		2124
		2125	Output of the awbove on my system, showing reduced and full accuracy:
		2126
		2127	stat(/etc) mtime: 1534043702.020808
		2128	aio_stat(/etc) mtime: 1534043702.020807792
		2129
		2130
1861	=head3 MISCELLANEOUS FUNCTIONS	2131	=head3 MISCELLANEOUS FUNCTIONS
1862		2132
1863	IO::AIO implements some functions that might be useful, but are not	2133	IO::AIO implements some functions that are useful when you want to use
1864	asynchronous.	2134	some "Advanced I/O" function not available to in Perl, without going the
		2135	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2136	counterpart.
1865		2137
1866	=over 4	2138	=over 4
		2139
		2140	=item $numfd = IO::AIO::get_fdlimit
		2141
		2142	This function is I<EXPERIMENTAL> and subject to change.
		2143
		2144	Tries to find the current file descriptor limit and returns it, or
		2145	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2146	the highest valid file descriptor number.
		2147
		2148	=item IO::AIO::min_fdlimit [$numfd]
		2149
		2150	This function is I<EXPERIMENTAL> and subject to change.
		2151
		2152	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2153	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2154	is missing, it will try to set a very high limit, although this is not
		2155	recommended when you know the actual minimum that you require.
		2156
		2157	If the limit cannot be raised enough, the function makes a best-effort
		2158	attempt to increase the limit as much as possible, using various
		2159	tricks, while still failing. You can query the resulting limit using
		2160	C<IO::AIO::get_fdlimit>.
		2161
		2162	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2163	true.
1867		2164
1868	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2165	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1869		2166
1870	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2167	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1871	but is blocking (this makes most sense if you know the input data is	2168	but is blocking (this makes most sense if you know the input data is
…		…
1888	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2185	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1889		2186
1890	Simply calls the C<posix_madvise> function (see its	2187	Simply calls the C<posix_madvise> function (see its
1891	manpage for details). The following advice constants are	2188	manpage for details). The following advice constants are
1892	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2189	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1893	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2190	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2191	C<IO::AIO::MADV_DONTNEED>.
		2192
		2193	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2194	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2195	will be reduced to fit into the C<$scalar>.
1894		2196
1895	On systems that do not implement C<posix_madvise>, this function returns	2197	On systems that do not implement C<posix_madvise>, this function returns
1896	ENOSYS, otherwise the return value of C<posix_madvise>.	2198	ENOSYS, otherwise the return value of C<posix_madvise>.
1897		2199
1898	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2200	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1900	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2202	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1901	$scalar (see its manpage for details). The following protect	2203	$scalar (see its manpage for details). The following protect
1902	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2204	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1903	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2205	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1904		2206
		2207	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2208	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2209	will be reduced to fit into the C<$scalar>.
		2210
1905	On systems that do not implement C<mprotect>, this function returns	2211	On systems that do not implement C<mprotect>, this function returns
1906	ENOSYS, otherwise the return value of C<mprotect>.	2212	ENOSYS, otherwise the return value of C<mprotect>.
1907		2213
1908	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2214	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1909		2215
1910	Memory-maps a file (or anonymous memory range) and attaches it to the	2216	Memory-maps a file (or anonymous memory range) and attaches it to the
1911	given C<$scalar>, which will act like a string scalar.	2217	given C<$scalar>, which will act like a string scalar. Returns true on
		2218	success, and false otherwise.
1912		2219
		2220	The scalar must exist, but its contents do not matter - this means you
		2221	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2222	the scalar first.
		2223
1913	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2224	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1914	change the string length, and most read-only operations such as copying it	2225	which don't change the string length, and most read-only operations such
1915	or searching it with regexes and so on.	2226	as copying it or searching it with regexes and so on.
1916		2227
1917	Anything else is unsafe and will, at best, result in memory leaks.	2228	Anything else is unsafe and will, at best, result in memory leaks.
1918		2229
1919	The memory map associated with the C<$scalar> is automatically removed	2230	The memory map associated with the C<$scalar> is automatically removed
1920	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2231	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1921	C<IO::AIO::munmap> functions are called.	2232	or C<IO::AIO::munmap> functions are called on it.
1922		2233
1923	This calls the C<mmap>(2) function internally. See your system's manual	2234	This calls the C<mmap>(2) function internally. See your system's manual
1924	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2235	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1925		2236
1926	The C<$length> must be larger than zero and smaller than the actual	2237	The C<$length> must be larger than zero and smaller than the actual
1927	filesize.	2238	filesize.
1928		2239
1929	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2240	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1930	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2241	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1931		2242
1932	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2243	C<$flags> can be a combination of
1933	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2244	C<IO::AIO::MAP_SHARED> or
1934	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2245	C<IO::AIO::MAP_PRIVATE>,
		2246	or a number of system-specific flags (when not available, the are C<0>):
1935	(which is set to C<MAP_ANON> if your system only provides this	2247	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1936	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2248	C<IO::AIO::MAP_LOCKED>,
1937	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2249	C<IO::AIO::MAP_NORESERVE>,
		2250	C<IO::AIO::MAP_POPULATE>,
1938	C<IO::AIO::MAP_NONBLOCK>	2251	C<IO::AIO::MAP_NONBLOCK>,
		2252	C<IO::AIO::MAP_FIXED>,
		2253	C<IO::AIO::MAP_GROWSDOWN>,
		2254	C<IO::AIO::MAP_32BIT>,
		2255	C<IO::AIO::MAP_HUGETLB> or
		2256	C<IO::AIO::MAP_STACK>.
1939		2257
1940	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2258	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1941		2259
1942	C<$offset> is the offset from the start of the file - it generally must be	2260	C<$offset> is the offset from the start of the file - it generally must be
1943	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2261	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1956	my $fast_md5 = md5 $data;	2274	my $fast_md5 = md5 $data;
1957		2275
1958	=item IO::AIO::munmap $scalar	2276	=item IO::AIO::munmap $scalar
1959		2277
1960	Removes a previous mmap and undefines the C<$scalar>.	2278	Removes a previous mmap and undefines the C<$scalar>.
		2279
		2280	=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
		2281
		2282	Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
		2283	been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
		2284	C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
		2285
		2286	Returns true if successful, and false otherwise. If the underlying mmapped
		2287	region has changed address, then the true value has the numerical value
		2288	C<1>, otherwise it has the numerical value C<0>:
		2289
		2290	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		2291	or die "mremap: $!";
		2292
		2293	if ($success*1) {
		2294	warn "scalar has chanegd address in memory\n";
		2295	}
		2296
		2297	C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
		2298	implemented, but not supported and might go away in a future version.
		2299
		2300	On systems where this call is not supported or is not emulated, this call
		2301	returns falls and sets C<$!> to C<ENOSYS>.
		2302
		2303	=item IO::AIO::mlockall $flags
		2304
		2305	Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
		2306	but is blocking.
1961		2307
1962	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef	2308	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1963		2309
1964	Calls the C<munlock> function, undoing the effects of a previous	2310	Calls the C<munlock> function, undoing the effects of a previous
1965	C<aio_mlock> call (see its description for details).	2311	C<aio_mlock> call (see its description for details).
…		…
1975		2321
1976	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or	2322	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1977	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they	2323	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
1978	should be the file offset.	2324	should be the file offset.
1979		2325
		2326	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2327	silently corrupt the data in this case.
		2328
1980	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,	2329	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
1981	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and	2330	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
1982	C<IO::AIO::SPLICE_F_GIFT>.	2331	C<IO::AIO::SPLICE_F_GIFT>.
1983		2332
1984	See the C<splice(2)> manpage for details.	2333	See the C<splice(2)> manpage for details.
1985		2334
1986	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags	2335	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
1987		2336
1988	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the	2337	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
1989	description for C<IO::AIO::splice> above for details.	2338	description for C<IO::AIO::splice> above for details.
		2339
		2340	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2341
		2342	Attempts to query or change the pipe buffer size. Obviously works only
		2343	on pipes, and currently works only on GNU/Linux systems, and fails with
		2344	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2345	size on other systems, drop me a note.
		2346
		2347	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2348
		2349	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2350	C<$flags> is missing or C<0>, then this should be the same as a call to
		2351	perl's built-in C<pipe> function and create a new pipe, and works on
		2352	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2353	(..., 4096, O_BINARY)>.
		2354
		2355	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2356	the given flags (Linux 2.6.27, glibc 2.9).
		2357
		2358	On success, the read and write file handles are returned.
		2359
		2360	On error, nothing will be returned. If the pipe2 syscall is missing and
		2361	C<$flags> is non-zero, fails with C<ENOSYS>.
		2362
		2363	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2364	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2365	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2366
		2367	Example: create a pipe race-free w.r.t. threads and fork:
		2368
		2369	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2370	or die "pipe2: $!\n";
		2371
		2372	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2373
		2374	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2375	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2376
		2377	On success, the new eventfd filehandle is returned, otherwise returns
		2378	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2379
		2380	Please refer to L<eventfd(2)> for more info on this call.
		2381
		2382	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2383	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2384
		2385	Example: create a new eventfd filehandle:
		2386
		2387	$fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
		2388	or die "eventfd: $!\n";
		2389
		2390	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2391
		2392	This is a direct interface to the Linux L<timerfd_create(2)> system call. The
		2393	(unhelpful) default for C<$flags> is C<0>.
		2394
		2395	On success, the new timerfd filehandle is returned, otherwise returns
		2396	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2397
		2398	Please refer to L<timerfd_create(2)> for more info on this call.
		2399
		2400	The following C<$clockid> values are
		2401	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2402	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2403	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2404	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2405
		2406	The following C<$flags> values are available (Linux
		2407	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2408
		2409	Example: create a new timerfd and set it to one-second repeated alarms,
		2410	then wait for two alarms:
		2411
		2412	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2413	or die "timerfd_create: $!\n";
		2414
		2415	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2416	or die "timerfd_settime: $!\n";
		2417
		2418	for (1..2) {
		2419	8 == sysread $fh, my $buf, 8
		2420	or die "timerfd read failure\n";
		2421
		2422	printf "number of expirations (likely 1): %d\n",
		2423	unpack "Q", $buf;
		2424	}
		2425
		2426	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2427
		2428	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2429	call. Please refer to its manpage for more info on this call.
		2430
		2431	The new itimerspec is specified using two (possibly fractional) second
		2432	values, C<$new_interval> and C<$new_value>).
		2433
		2434	On success, the current interval and value are returned (as per
		2435	C<timerfd_gettime>). On failure, the empty list is returned.
		2436
		2437	The following C<$flags> values are
		2438	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2439	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2440
		2441	See C<IO::AIO::timerfd_create> for a full example.
		2442
		2443	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2444
		2445	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2446	call. Please refer to its manpage for more info on this call.
		2447
		2448	On success, returns the current values of interval and value for the given
		2449	timerfd (as potentially fractional second values). On failure, the empty
		2450	list is returned.
1990		2451
1991	=back	2452	=back
1992		2453
1993	=cut	2454	=cut
1994		2455
…		…
2060	the process will result in undefined behaviour. Calling it at any time	2521	the process will result in undefined behaviour. Calling it at any time
2061	will also result in any undefined (by POSIX) behaviour.	2522	will also result in any undefined (by POSIX) behaviour.
2062		2523
2063	=back	2524	=back
2064		2525
		2526	=head2 LINUX-SPECIFIC CALLS
		2527
		2528	When a call is documented as "linux-specific" then this means it
		2529	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2530	availability and compatibility of such calls regardless of the platform
		2531	it is compiled on, so platforms such as FreeBSD which often implement
		2532	these calls will work. When in doubt, call them and see if they fail wth
		2533	C<ENOSYS>.
		2534
2065	=head2 MEMORY USAGE	2535	=head2 MEMORY USAGE
2066		2536
2067	Per-request usage:	2537	Per-request usage:
2068		2538
2069	Each aio request uses - depending on your architecture - around 100-200	2539	Each aio request uses - depending on your architecture - around 100-200
…		…
2081	temporary buffers, and each thread requires a stack and other data	2551	temporary buffers, and each thread requires a stack and other data
2082	structures (usually around 16k-128k, depending on the OS).	2552	structures (usually around 16k-128k, depending on the OS).
2083		2553
2084	=head1 KNOWN BUGS	2554	=head1 KNOWN BUGS
2085		2555
2086	Known bugs will be fixed in the next release.	2556	Known bugs will be fixed in the next release :)
		2557
		2558	=head1 KNOWN ISSUES
		2559
		2560	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2561	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2562	non-created hash slots or other scalars I didn't think of. It's best to
		2563	avoid such and either use scalar variables or making sure that the scalar
		2564	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2565
		2566	I am not sure anything can be done about this, so this is considered a
		2567	known issue, rather than a bug.
2087		2568
2088	=head1 SEE ALSO	2569	=head1 SEE ALSO
2089		2570
2090	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2571	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2091	more natural syntax.	2572	more natural syntax.

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.225 by root, Tue Apr 10 05:01:33 2012 UTC vs. Revision 1.298 by root, Thu Nov 29 21:48:44 2018 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.225 by root, Tue Apr 10 05:01:33 2012 UTC vs.
Revision 1.298 by root, Thu Nov 29 21:48:44 2018 UTC