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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.231 by root, Fri Jul 27 19:03:18 2012 UTC vs.
Revision 1.287 by root, Tue Jul 24 04:58:59 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 = 4.42;
174		177
175	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close	178	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	179	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate	181	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179	aio_pathsync aio_readahead aio_fiemap	182	aio_pathsync aio_readahead aio_fiemap aio_allocate
180	aio_rename aio_link aio_move aio_copy aio_group	183	aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	184	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182	aio_chmod aio_utime aio_truncate	185	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	186	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs	187	aio_statvfs
		188	aio_slurp
185	aio_wd);	189	aio_wd);
186		190
187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	191	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	192	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189	min_parallel max_parallel max_idle idle_timeout	193	min_parallel max_parallel max_idle idle_timeout
190	nreqs nready npending nthreads	194	nreqs nready npending nthreads
191	max_poll_time max_poll_reqs	195	max_poll_time max_poll_reqs
192	sendfile fadvise madvise	196	sendfile fadvise madvise
193	mmap munmap munlock munlockall);	197	mmap munmap mremap munlock munlockall);
194		198
195	push @AIO_REQ, qw(aio_busy); # not exported	199	push @AIO_REQ, qw(aio_busy); # not exported
196		200
197	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	201	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
198		202
…		…
228	aio_unlink $pathname, $callback->($status)	232	aio_unlink $pathname, $callback->($status)
229	aio_mknod $pathname, $mode, $dev, $callback->($status)	233	aio_mknod $pathname, $mode, $dev, $callback->($status)
230	aio_link $srcpath, $dstpath, $callback->($status)	234	aio_link $srcpath, $dstpath, $callback->($status)
231	aio_symlink $srcpath, $dstpath, $callback->($status)	235	aio_symlink $srcpath, $dstpath, $callback->($status)
232	aio_readlink $pathname, $callback->($link)	236	aio_readlink $pathname, $callback->($link)
233	aio_realpath $pathname, $callback->($link)	237	aio_realpath $pathname, $callback->($path)
234	aio_rename $srcpath, $dstpath, $callback->($status)	238	aio_rename $srcpath, $dstpath, $callback->($status)
		239	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
235	aio_mkdir $pathname, $mode, $callback->($status)	240	aio_mkdir $pathname, $mode, $callback->($status)
236	aio_rmdir $pathname, $callback->($status)	241	aio_rmdir $pathname, $callback->($status)
237	aio_readdir $pathname, $callback->($entries)	242	aio_readdir $pathname, $callback->($entries)
238	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	243	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
239	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	244	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
…		…
241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)	246	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242	aio_load $pathname, $data, $callback->($status)	247	aio_load $pathname, $data, $callback->($status)
243	aio_copy $srcpath, $dstpath, $callback->($status)	248	aio_copy $srcpath, $dstpath, $callback->($status)
244	aio_move $srcpath, $dstpath, $callback->($status)	249	aio_move $srcpath, $dstpath, $callback->($status)
245	aio_rmtree $pathname, $callback->($status)	250	aio_rmtree $pathname, $callback->($status)
		251	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		252	aio_ioctl $fh, $request, $buf, $callback->($status)
246	aio_sync $callback->($status)	253	aio_sync $callback->($status)
247	aio_syncfs $fh, $callback->($status)	254	aio_syncfs $fh, $callback->($status)
248	aio_fsync $fh, $callback->($status)	255	aio_fsync $fh, $callback->($status)
249	aio_fdatasync $fh, $callback->($status)	256	aio_fdatasync $fh, $callback->($status)
250	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	257	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
251	aio_pathsync $pathname, $callback->($status)	258	aio_pathsync $pathname, $callback->($status)
252	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
253	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	260	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
254	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	261	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
255	aio_mlockall $flags, $callback->($status)	262	aio_mlockall $flags, $callback->($status)
256	aio_group $callback->(...)	263	aio_group $callback->(...)
257	aio_nop $callback->()	264	aio_nop $callback->()
…		…
271	IO::AIO::idle_timeout $seconds	278	IO::AIO::idle_timeout $seconds
272	IO::AIO::max_outstanding $maxreqs	279	IO::AIO::max_outstanding $maxreqs
273	IO::AIO::nreqs	280	IO::AIO::nreqs
274	IO::AIO::nready	281	IO::AIO::nready
275	IO::AIO::npending	282	IO::AIO::npending
		283	$nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
		284	IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
276		285
277	IO::AIO::sendfile $ofh, $ifh, $offset, $count	286	IO::AIO::sendfile $ofh, $ifh, $offset, $count
278	IO::AIO::fadvise $fh, $offset, $len, $advice	287	IO::AIO::fadvise $fh, $offset, $len, $advice
279	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]	288	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280	IO::AIO::munmap $scalar	289	IO::AIO::munmap $scalar
		290	IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
281	IO::AIO::madvise $scalar, $offset, $length, $advice	291	IO::AIO::madvise $scalar, $offset, $length, $advice
282	IO::AIO::mprotect $scalar, $offset, $length, $protect	292	IO::AIO::mprotect $scalar, $offset, $length, $protect
283	IO::AIO::munlock $scalar, $offset = 0, $length = undef	293	IO::AIO::munlock $scalar, $offset = 0, $length = undef
284	IO::AIO::munlockall	294	IO::AIO::munlockall
285		295
…		…
362		372
363		373
364	=item aio_open $pathname, $flags, $mode, $callback->($fh)	374	=item aio_open $pathname, $flags, $mode, $callback->($fh)
365		375
366	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
367	created filehandle for the file.	377	created filehandle for the file (or C<undef> in case of an error).
368		378
369	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,
370	for an explanation.	380	for an explanation.
371		381
372	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
…		…
395	following POSIX and non-POSIX constants are available (missing ones on	405	following POSIX and non-POSIX constants are available (missing ones on
396	your system are, as usual, C<0>):	406	your system are, as usual, C<0>):
397		407
398	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>,
399	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>,
400	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>.
401		411
402		412
403	=item aio_close $fh, $callback->($status)	413	=item aio_close $fh, $callback->($status)
404		414
405	Asynchronously close a file and call the callback with the result	415	Asynchronously close a file and call the callback with the result
…		…
440	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	450	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441		451
442	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	452	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443		453
444	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
445	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
446	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
447	error, just like the syscall).	457	error, just like the syscall).
448		458
449	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
450	offset plus the actual number of bytes read.	460	offset plus the actual number of bytes read.
451		461
…		…
509	As native sendfile syscalls (as practically any non-POSIX interface hacked	519	As native sendfile syscalls (as practically any non-POSIX interface hacked
510	together in a hurry to improve benchmark numbers) tend to be rather buggy	520	together in a hurry to improve benchmark numbers) tend to be rather buggy
511	on many systems, this implementation tries to work around some known bugs	521	on many systems, this implementation tries to work around some known bugs
512	in Linux and FreeBSD kernels (probably others, too), but that might fail,	522	in Linux and FreeBSD kernels (probably others, too), but that might fail,
513	so you really really should check the return value of C<aio_sendfile> -	523	so you really really should check the return value of C<aio_sendfile> -
514	fewre bytes than expected might have been transferred.	524	fewer bytes than expected might have been transferred.
515		525
516		526
517	=item aio_readahead $fh,$offset,$length, $callback->($retval)	527	=item aio_readahead $fh,$offset,$length, $callback->($retval)
518		528
519	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
…		…
523	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
524	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
525	(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
526	file. The current file offset of the file is left unchanged.	536	file. The current file offset of the file is left unchanged.
527		537
528	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
529	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.
530		540
531		541
532	=item aio_stat $fh_or_path, $callback->($status)	542	=item aio_stat $fh_or_path, $callback->($status)
533		543
534	=item aio_lstat $fh, $callback->($status)	544	=item aio_lstat $fh, $callback->($status)
…		…
603	namemax => 255,	613	namemax => 255,
604	frsize => 1024,	614	frsize => 1024,
605	fsid => 1810	615	fsid => 1810
606	}	616	}
607		617
608
609	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	618	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
610		619
611	Works like perl's C<utime> function (including the special case of $atime	620	Works like perl's C<utime> function (including the special case of $atime
612	and $mtime being undef). Fractional times are supported if the underlying	621	and $mtime being undef). Fractional times are supported if the underlying
613	syscalls support them.	622	syscalls support them.
…		…
642	Works like truncate(2) or ftruncate(2).	651	Works like truncate(2) or ftruncate(2).
643		652
644		653
645	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)	654	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
646		655
647	Allocates or freed disk space according to the C<$mode> argument. See the	656	Allocates or frees disk space according to the C<$mode> argument. See the
648	linux C<fallocate> docuemntation for details.	657	linux C<fallocate> documentation for details.
649		658
650	C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>	659	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
651	to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \|	660	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
652	IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.	661	to deallocate a file range.
		662
		663	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		664	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		665	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		666	to unshare shared blocks (see your L<fallocate(2)> manpage).
653		667
654	The file system block size used by C<fallocate> is presumably the	668	The file system block size used by C<fallocate> is presumably the
655	C<f_bsize> returned by C<statvfs>.	669	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		670	can dictate other limitations.
656		671
657	If C<fallocate> isn't available or cannot be emulated (currently no	672	If C<fallocate> isn't available or cannot be emulated (currently no
658	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.	673	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
659		674
660		675
…		…
702		717
703		718
704	=item aio_realpath $pathname, $callback->($path)	719	=item aio_realpath $pathname, $callback->($path)
705		720
706	Asynchronously make the path absolute and resolve any symlinks in	721	Asynchronously make the path absolute and resolve any symlinks in
707	C<$path>. The resulting path only consists of directories (Same as	722	C<$path>. The resulting path only consists of directories (same as
708	L<Cwd::realpath>).	723	L<Cwd::realpath>).
709		724
710	This request can be used to get the absolute path of the current working	725	This request can be used to get the absolute path of the current working
711	directory by passing it a path of F<.> (a single dot).	726	directory by passing it a path of F<.> (a single dot).
712		727
713		728
714	=item aio_rename $srcpath, $dstpath, $callback->($status)	729	=item aio_rename $srcpath, $dstpath, $callback->($status)
715		730
716	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	731	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
717	rename(2) and call the callback with the result code.	732	rename(2) and call the callback with the result code.
		733
		734	On systems that support the AIO::WD working directory abstraction
		735	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		736	of failing, C<rename> is called on the absolute path of C<$wd>.
		737
		738
		739	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		740
		741	Basically a version of C<aio_rename> with an additional C<$flags>
		742	argument. Calling this with C<$flags=0> is the same as calling
		743	C<aio_rename>.
		744
		745	Non-zero flags are currently only supported on GNU/Linux systems that
		746	support renameat2. Other systems fail with C<ENOSYS> in this case.
		747
		748	The following constants are available (missing ones are, as usual C<0>),
		749	see renameat2(2) for details:
		750
		751	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		752	and C<IO::AIO::RENAME_WHITEOUT>.
718		753
719		754
720	=item aio_mkdir $pathname, $mode, $callback->($status)	755	=item aio_mkdir $pathname, $mode, $callback->($status)
721		756
722	Asynchronously mkdir (create) a directory and call the callback with	757	Asynchronously mkdir (create) a directory and call the callback with
…		…
727	=item aio_rmdir $pathname, $callback->($status)	762	=item aio_rmdir $pathname, $callback->($status)
728		763
729	Asynchronously rmdir (delete) a directory and call the callback with the	764	Asynchronously rmdir (delete) a directory and call the callback with the
730	result code.	765	result code.
731		766
		767	On systems that support the AIO::WD working directory abstraction
		768	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		769	C<rmdir> is called on the absolute path of C<$wd>.
		770
732		771
733	=item aio_readdir $pathname, $callback->($entries)	772	=item aio_readdir $pathname, $callback->($entries)
734		773
735	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	774	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
736	directory (i.e. opendir + readdir + closedir). The entries will not be	775	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
751		790
752	=over 4	791	=over 4
753		792
754	=item IO::AIO::READDIR_DENTS	793	=item IO::AIO::READDIR_DENTS
755		794
756	When this flag is off, then the callback gets an arrayref consisting of	795	Normally the callback gets an arrayref consisting of names only (as
757	names only (as with C<aio_readdir>), otherwise it gets an arrayref with	796	with C<aio_readdir>). If this flag is set, then the callback gets an
758	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	797	arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
759	entry in more detail.	798	single directory entry in more detail:
760		799
761	C<$name> is the name of the entry.	800	C<$name> is the name of the entry.
762		801
763	C<$type> is one of the C<IO::AIO::DT_xxx> constants:	802	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
764		803
765	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,	804	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
766	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,	805	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
767	C<IO::AIO::DT_WHT>.	806	C<IO::AIO::DT_WHT>.
768		807
769	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to	808	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
770	know, you have to run stat yourself. Also, for speed reasons, the C<$type>	809	to know, you have to run stat yourself. Also, for speed/memory reasons,
771	scalars are read-only: you can not modify them.	810	the C<$type> scalars are read-only: you must not modify them.
772		811
773	C<$inode> is the inode number (which might not be exact on systems with 64	812	C<$inode> is the inode number (which might not be exact on systems with 64
774	bit inode numbers and 32 bit perls). This field has unspecified content on	813	bit inode numbers and 32 bit perls). This field has unspecified content on
775	systems that do not deliver the inode information.	814	systems that do not deliver the inode information.
776		815
…		…
787	short names are tried first.	826	short names are tried first.
788		827
789	=item IO::AIO::READDIR_STAT_ORDER	828	=item IO::AIO::READDIR_STAT_ORDER
790		829
791	When this flag is set, then the names will be returned in an order	830	When this flag is set, then the names will be returned in an order
792	suitable for stat()'ing each one. That is, when you plan to stat()	831	suitable for stat()'ing each one. That is, when you plan to stat() most or
793	all files in the given directory, then the returned order will likely	832	all files in the given directory, then the returned order will likely be
794	be fastest.	833	faster.
795		834
796	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then	835	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
797	the likely dirs come first, resulting in a less optimal stat order.	836	then the likely dirs come first, resulting in a less optimal stat order
		837	for stat'ing all entries, but likely a more optimal order for finding
		838	subdirectories.
798		839
799	=item IO::AIO::READDIR_FOUND_UNKNOWN	840	=item IO::AIO::READDIR_FOUND_UNKNOWN
800		841
801	This flag should not be set when calling C<aio_readdirx>. Instead, it	842	This flag should not be set when calling C<aio_readdirx>. Instead, it
802	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	843	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
…		…
804	C<$type>'s are known, which can be used to speed up some algorithms.	845	C<$type>'s are known, which can be used to speed up some algorithms.
805		846
806	=back	847	=back
807		848
808		849
		850	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		851
		852	Opens, reads and closes the given file. The data is put into C<$data>,
		853	which is resized as required.
		854
		855	If C<$offset> is negative, then it is counted from the end of the file.
		856
		857	If C<$length> is zero, then the remaining length of the file is
		858	used. Also, in this case, the same limitations to modifying C<$data> apply
		859	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		860	with C<substr>. If the size of the file is known, specifying a non-zero
		861	C<$length> results in a performance advantage.
		862
		863	This request is similar to the older C<aio_load> request, but since it is
		864	a single request, it might be more efficient to use.
		865
		866	Example: load F</etc/passwd> into C<$passwd>.
		867
		868	my $passwd;
		869	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		870	$_[0] >= 0
		871	or die "/etc/passwd: $!\n";
		872
		873	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		874	print $passwd;
		875	};
		876	IO::AIO::flush;
		877
		878
809	=item aio_load $pathname, $data, $callback->($status)	879	=item aio_load $pathname, $data, $callback->($status)
810		880
811	This is a composite request that tries to fully load the given file into	881	This is a composite request that tries to fully load the given file into
812	memory. Status is the same as with aio_read.	882	memory. Status is the same as with aio_read.
		883
		884	Using C<aio_slurp> might be more efficient, as it is a single request.
813		885
814	=cut	886	=cut
815		887
816	sub aio_load($$;$) {	888	sub aio_load($$;$) {
817	my ($path, undef, $cb) = @_;	889	my ($path, undef, $cb) = @_;
…		…
837	=item aio_copy $srcpath, $dstpath, $callback->($status)	909	=item aio_copy $srcpath, $dstpath, $callback->($status)
838		910
839	Try to copy the I<file> (directories not supported as either source or	911	Try to copy the I<file> (directories not supported as either source or
840	destination) from C<$srcpath> to C<$dstpath> and call the callback with	912	destination) from C<$srcpath> to C<$dstpath> and call the callback with
841	a status of C<0> (ok) or C<-1> (error, see C<$!>).	913	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		914
		915	Existing destination files will be truncated.
842		916
843	This is a composite request that creates the destination file with	917	This is a composite request that creates the destination file with
844	mode 0200 and copies the contents of the source file into it using	918	mode 0200 and copies the contents of the source file into it using
845	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	919	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
846	uid/gid, in that order.	920	uid/gid, in that order.
…		…
956	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1030	Scans a directory (similar to C<aio_readdir>) but additionally tries to
957	efficiently separate the entries of directory C<$path> into two sets of	1031	efficiently separate the entries of directory C<$path> into two sets of
958	names, directories you can recurse into (directories), and ones you cannot	1032	names, directories you can recurse into (directories), and ones you cannot
959	recurse into (everything else, including symlinks to directories).	1033	recurse into (everything else, including symlinks to directories).
960		1034
961	C<aio_scandir> is a composite request that creates of many sub requests_	1035	C<aio_scandir> is a composite request that generates many sub requests.
962	C<$maxreq> specifies the maximum number of outstanding aio requests that	1036	C<$maxreq> specifies the maximum number of outstanding aio requests that
963	this function generates. If it is C<< <= 0 >>, then a suitable default	1037	this function generates. If it is C<< <= 0 >>, then a suitable default
964	will be chosen (currently 4).	1038	will be chosen (currently 4).
965		1039
966	On error, the callback is called without arguments, otherwise it receives	1040	On error, the callback is called without arguments, otherwise it receives
…		…
1100	}	1174	}
1101		1175
1102	=item aio_rmtree $pathname, $callback->($status)	1176	=item aio_rmtree $pathname, $callback->($status)
1103		1177
1104	Delete a directory tree starting (and including) C<$path>, return the	1178	Delete a directory tree starting (and including) C<$path>, return the
1105	status of the final C<rmdir> only. This is a composite request that	1179	status of the final C<rmdir> only. This is a composite request that
1106	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1180	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1107	everything else.	1181	everything else.
1108		1182
1109	=cut	1183	=cut
1110		1184
…		…
1131	add $grp $dirgrp;	1205	add $grp $dirgrp;
1132	};	1206	};
1133		1207
1134	$grp	1208	$grp
1135	}	1209	}
		1210
		1211	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1212
		1213	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1214
		1215	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1216	they execute asynchronously and pass the return value to the callback.
		1217
		1218	Both calls can be used for a lot of things, some of which make more sense
		1219	to run asynchronously in their own thread, while some others make less
		1220	sense. For example, calls that block waiting for external events, such
		1221	as locking, will also lock down an I/O thread while it is waiting, which
		1222	can deadlock the whole I/O system. At the same time, there might be no
		1223	alternative to using a thread to wait.
		1224
		1225	So in general, you should only use these calls for things that do
		1226	(filesystem) I/O, not for things that wait for other events (network,
		1227	other processes), although if you are careful and know what you are doing,
		1228	you still can.
		1229
		1230	The following constants are available (missing ones are, as usual C<0>):
		1231
		1232	C<F_DUPFD_CLOEXEC>,
		1233
		1234	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1235
		1236	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1237
		1238	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1239	C<FS_IOC_FIEMAP>.
		1240
		1241	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1242	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1243
		1244	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1245	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1246	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1247	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1248	C<FS_FL_USER_MODIFIABLE>.
		1249
		1250	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1251	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1252	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1253	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1136		1254
1137	=item aio_sync $callback->($status)	1255	=item aio_sync $callback->($status)
1138		1256
1139	Asynchronously call sync and call the callback when finished.	1257	Asynchronously call sync and call the callback when finished.
1140		1258
…		…
1209	};	1327	};
1210		1328
1211	$grp	1329	$grp
1212	}	1330	}
1213		1331
1214	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1332	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1215		1333
1216	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1334	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1217	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1335	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1218	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1336	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1219	scalar must only be modified in-place while an aio operation is pending on	1337	scalar must only be modified in-place while an aio operation is pending on
…		…
1221		1339
1222	It calls the C<msync> function of your OS, if available, with the memory	1340	It calls the C<msync> function of your OS, if available, with the memory
1223	area starting at C<$offset> in the string and ending C<$length> bytes	1341	area starting at C<$offset> in the string and ending C<$length> bytes
1224	later. If C<$length> is negative, counts from the end, and if C<$length>	1342	later. If C<$length> is negative, counts from the end, and if C<$length>
1225	is C<undef>, then it goes till the end of the string. The flags can be	1343	is C<undef>, then it goes till the end of the string. The flags can be
1226	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1344	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1227	C<IO::AIO::MS_SYNC>.	1345	C<IO::AIO::MS_INVALIDATE>.
1228		1346
1229	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1347	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1230		1348
1231	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1349	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1232	scalars.	1350	scalars.
1233		1351
1234	It touches (reads or writes) all memory pages in the specified	1352	It touches (reads or writes) all memory pages in the specified
1235	range inside the scalar. All caveats and parameters are the same	1353	range inside the scalar. All caveats and parameters are the same
1236	as for C<aio_msync>, above, except for flags, which must be either	1354	as for C<aio_msync>, above, except for flags, which must be either
1237	C<0> (which reads all pages and ensures they are instantiated) or	1355	C<0> (which reads all pages and ensures they are instantiated) or
1238	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1356	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1239	writing an octet from it, which dirties the page).	1357	writing an octet from it, which dirties the page).
1240		1358
1241	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1359	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1242		1360
1243	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1361	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1277		1395
1278	aio_mlockall IO::AIO::MCL_FUTURE;	1396	aio_mlockall IO::AIO::MCL_FUTURE;
1279		1397
1280	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)	1398	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1281		1399
1282	Queries the extents of the given file (by calling the Linux FIEMAP ioctl,	1400	Queries the extents of the given file (by calling the Linux C<FIEMAP>
1283	see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the	1401	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1284	C<ioctl> is not available on your OS, then this request will fail with	1402	the ioctl is not available on your OS, then this request will fail with
1285	C<ENOSYS>.	1403	C<ENOSYS>.
1286		1404
1287	C<$start> is the starting offset to query extents for, C<$length> is the	1405	C<$start> is the starting offset to query extents for, C<$length> is the
1288	size of the range to query - if it is C<undef>, then the whole file will	1406	size of the range to query - if it is C<undef>, then the whole file will
1289	be queried.	1407	be queried.
…		…
1292	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also	1410	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1293	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query	1411	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1294	the data portion.	1412	the data portion.
1295		1413
1296	C<$count> is the maximum number of extent records to return. If it is	1414	C<$count> is the maximum number of extent records to return. If it is
1297	C<undef>, then IO::AIO queries all extents of the file. As a very special	1415	C<undef>, then IO::AIO queries all extents of the range. As a very special
1298	case, if it is C<0>, then the callback receives the number of extents	1416	case, if it is C<0>, then the callback receives the number of extents
1299	instead of the extents themselves.	1417	instead of the extents themselves (which is unreliable, see below).
1300		1418
1301	If an error occurs, the callback receives no arguments. The special	1419	If an error occurs, the callback receives no arguments. The special
1302	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.	1420	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1303		1421
1304	Otherwise, the callback receives an array reference with extent	1422	Otherwise, the callback receives an array reference with extent
…		…
1315	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,	1433	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1316	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,	1434	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1317	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or	1435	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1318	C<IO::AIO::FIEMAP_EXTENT_SHARED>.	1436	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1319		1437
		1438	At the time of this writing (Linux 3.2), this request is unreliable unless
		1439	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1440	it to return all extents of a range for files with a large number of
		1441	extents. The code (only) works around all these issues if C<$count> is
		1442	C<undef>.
		1443
1320	=item aio_group $callback->(...)	1444	=item aio_group $callback->(...)
1321		1445
1322	This is a very special aio request: Instead of doing something, it is a	1446	This is a very special aio request: Instead of doing something, it is a
1323	container for other aio requests, which is useful if you want to bundle	1447	container for other aio requests, which is useful if you want to bundle
1324	many requests into a single, composite, request with a definite callback	1448	many requests into a single, composite, request with a definite callback
…		…
1407	aio_stat [$etcdir, "passwd"], sub {	1531	aio_stat [$etcdir, "passwd"], sub {
1408	# yay	1532	# yay
1409	};	1533	};
1410	};	1534	};
1411		1535
1412	That C<aio_wd> is a request and not a normal function shows that creating	1536	The fact that C<aio_wd> is a request and not a normal function shows that
1413	an IO::AIO::WD object is itself a potentially blocking operation, which is	1537	creating an IO::AIO::WD object is itself a potentially blocking operation,
1414	why it is done asynchronously.	1538	which is why it is done asynchronously.
1415		1539
1416	To stat the directory obtained with C<aio_wd> above, one could write	1540	To stat the directory obtained with C<aio_wd> above, one could write
1417	either of the following three request calls:	1541	either of the following three request calls:
1418		1542
1419	aio_lstat "/etc" , sub { ... # pathname as normal string	1543	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1436	There are some caveats: when directories get renamed (or deleted), the	1560	There are some caveats: when directories get renamed (or deleted), the
1437	pathname string doesn't change, so will point to the new directory (or	1561	pathname string doesn't change, so will point to the new directory (or
1438	nowhere at all), while the directory fd, if available on the system,	1562	nowhere at all), while the directory fd, if available on the system,
1439	will still point to the original directory. Most functions accepting a	1563	will still point to the original directory. Most functions accepting a
1440	pathname will use the directory fd on newer systems, and the string on	1564	pathname will use the directory fd on newer systems, and the string on
1441	older systems. Some functions (such as realpath) will always rely on the	1565	older systems. Some functions (such as C<aio_realpath>) will always rely on
1442	string form of the pathname.	1566	the string form of the pathname.
1443		1567
1444	So this fucntionality is mainly useful to get some protection against	1568	So this functionality is mainly useful to get some protection against
1445	C<chdir>, to easily get an absolute path out of a relative path for future	1569	C<chdir>, to easily get an absolute path out of a relative path for future
1446	reference, and to speed up doing many operations in the same directory	1570	reference, and to speed up doing many operations in the same directory
1447	(e.g. when stat'ing all files in a directory).	1571	(e.g. when stat'ing all files in a directory).
1448		1572
1449	The following functions implement this working directory abstraction:	1573	The following functions implement this working directory abstraction:
…		…
1462	passing C<undef> as working directory component of a pathname fails the	1586	passing C<undef> as working directory component of a pathname fails the
1463	request with C<ENOENT>, there is often no need for error checking in the	1587	request with C<ENOENT>, there is often no need for error checking in the
1464	C<aio_wd> callback, as future requests using the value will fail in the	1588	C<aio_wd> callback, as future requests using the value will fail in the
1465	expected way.	1589	expected way.
1466		1590
1467	If this call isn't available because your OS lacks it or it couldn't be
1468	detected, it will be emulated by calling C<fsync> instead.
1469
1470	=item IO::AIO::CWD	1591	=item IO::AIO::CWD
1471		1592
1472	This is a compiletime constant (object) that represents the process	1593	This is a compiletime constant (object) that represents the process
1473	current working directory.	1594	current working directory.
1474		1595
1475	Specifying this object as working directory object for a pathname is as	1596	Specifying this object as working directory object for a pathname is as if
1476	if the pathname would be specified directly, without a directory object,	1597	the pathname would be specified directly, without a directory object. For
1477	e.g., these calls are functionally identical:	1598	example, these calls are functionally identical:
1478		1599
1479	aio_stat "somefile", sub { ... };	1600	aio_stat "somefile", sub { ... };
1480	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1601	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1481		1602
1482	=back	1603	=back
1483		1604
		1605	To recover the path associated with an IO::AIO::WD object, you can use
		1606	C<aio_realpath>:
		1607
		1608	aio_realpath $wd, sub {
		1609	warn "path is $_[0]\n";
		1610	};
		1611
		1612	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1613	sometimes, fall back to using an absolue path.
1484		1614
1485	=head2 IO::AIO::REQ CLASS	1615	=head2 IO::AIO::REQ CLASS
1486		1616
1487	All non-aggregate C<aio_*> functions return an object of this class when	1617	All non-aggregate C<aio_*> functions return an object of this class when
1488	called in non-void context.	1618	called in non-void context.
…		…
1666		1796
1667	See C<poll_cb> for an example.	1797	See C<poll_cb> for an example.
1668		1798
1669	=item IO::AIO::poll_cb	1799	=item IO::AIO::poll_cb
1670		1800
1671	Process some outstanding events on the result pipe. You have to call	1801	Process some requests that have reached the result phase (i.e. they have
		1802	been executed but the results are not yet reported). You have to call
		1803	this "regularly" to finish outstanding requests.
		1804
1672	this regularly. Returns C<0> if all events could be processed (or there	1805	Returns C<0> if all events could be processed (or there were no
1673	were no events to process), or C<-1> if it returned earlier for whatever	1806	events to process), or C<-1> if it returned earlier for whatever
1674	reason. Returns immediately when no events are outstanding. The amount of	1807	reason. Returns immediately when no events are outstanding. The amount
1675	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1808	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1676	C<IO::AIO::max_poll_time>.	1809	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1677		1810
1678	If not all requests were processed for whatever reason, the filehandle	1811	If not all requests were processed for whatever reason, the poll file
1679	will still be ready when C<poll_cb> returns, so normally you don't have to	1812	descriptor will still be ready when C<poll_cb> returns, so normally you
1680	do anything special to have it called later.	1813	don't have to do anything special to have it called later.
1681		1814
1682	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1815	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1683	ready, it can be beneficial to call this function from loops which submit	1816	ready, it can be beneficial to call this function from loops which submit
1684	a lot of requests, to make sure the results get processed when they become	1817	a lot of requests, to make sure the results get processed when they become
1685	available and not just when the loop is finished and the event loop takes	1818	available and not just when the loop is finished and the event loop takes
…		…
1694	poll => 'r', async => 1,	1827	poll => 'r', async => 1,
1695	cb => \&IO::AIO::poll_cb);	1828	cb => \&IO::AIO::poll_cb);
1696		1829
1697	=item IO::AIO::poll_wait	1830	=item IO::AIO::poll_wait
1698		1831
1699	If there are any outstanding requests and none of them in the result	1832	Wait until either at least one request is in the result phase or no
1700	phase, wait till the result filehandle becomes ready for reading (simply	1833	requests are outstanding anymore.
1701	does a C<select> on the filehandle. This is useful if you want to	1834
1702	synchronously wait for some requests to finish).	1835	This is useful if you want to synchronously wait for some requests to
		1836	become ready, without actually handling them.
1703		1837
1704	See C<nreqs> for an example.	1838	See C<nreqs> for an example.
1705		1839
1706	=item IO::AIO::poll	1840	=item IO::AIO::poll
1707		1841
…		…
1828		1962
1829	This is a very bad function to use in interactive programs because it	1963	This is a very bad function to use in interactive programs because it
1830	blocks, and a bad way to reduce concurrency because it is inexact: Better	1964	blocks, and a bad way to reduce concurrency because it is inexact: Better
1831	use an C<aio_group> together with a feed callback.	1965	use an C<aio_group> together with a feed callback.
1832		1966
1833	It's main use is in scripts without an event loop - when you want to stat	1967	Its main use is in scripts without an event loop - when you want to stat
1834	a lot of files, you can write somehting like this:	1968	a lot of files, you can write something like this:
1835		1969
1836	IO::AIO::max_outstanding 32;	1970	IO::AIO::max_outstanding 32;
1837		1971
1838	for my $path (...) {	1972	for my $path (...) {
1839	aio_stat $path , ...;	1973	aio_stat $path , ...;
…		…
1878		2012
1879	=back	2013	=back
1880		2014
1881	=head3 MISCELLANEOUS FUNCTIONS	2015	=head3 MISCELLANEOUS FUNCTIONS
1882		2016
1883	IO::AIO implements some functions that might be useful, but are not	2017	IO::AIO implements some functions that are useful when you want to use
1884	asynchronous.	2018	some "Advanced I/O" function not available to in Perl, without going the
		2019	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2020	counterpart.
1885		2021
1886	=over 4	2022	=over 4
		2023
		2024	=item $numfd = IO::AIO::get_fdlimit
		2025
		2026	This function is I<EXPERIMENTAL> and subject to change.
		2027
		2028	Tries to find the current file descriptor limit and returns it, or
		2029	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2030	the highest valid file descriptor number.
		2031
		2032	=item IO::AIO::min_fdlimit [$numfd]
		2033
		2034	This function is I<EXPERIMENTAL> and subject to change.
		2035
		2036	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2037	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2038	is missing, it will try to set a very high limit, although this is not
		2039	recommended when you know the actual minimum that you require.
		2040
		2041	If the limit cannot be raised enough, the function makes a best-effort
		2042	attempt to increase the limit as much as possible, using various
		2043	tricks, while still failing. You can query the resulting limit using
		2044	C<IO::AIO::get_fdlimit>.
		2045
		2046	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2047	true.
1887		2048
1888	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2049	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1889		2050
1890	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2051	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1891	but is blocking (this makes most sense if you know the input data is	2052	but is blocking (this makes most sense if you know the input data is
…		…
1908	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2069	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1909		2070
1910	Simply calls the C<posix_madvise> function (see its	2071	Simply calls the C<posix_madvise> function (see its
1911	manpage for details). The following advice constants are	2072	manpage for details). The following advice constants are
1912	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2073	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1913	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2074	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2075	C<IO::AIO::MADV_DONTNEED>.
		2076
		2077	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2078	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2079	will be reduced to fit into the C<$scalar>.
1914		2080
1915	On systems that do not implement C<posix_madvise>, this function returns	2081	On systems that do not implement C<posix_madvise>, this function returns
1916	ENOSYS, otherwise the return value of C<posix_madvise>.	2082	ENOSYS, otherwise the return value of C<posix_madvise>.
1917		2083
1918	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2084	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1920	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2086	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1921	$scalar (see its manpage for details). The following protect	2087	$scalar (see its manpage for details). The following protect
1922	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2088	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1923	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2089	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1924		2090
		2091	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2092	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2093	will be reduced to fit into the C<$scalar>.
		2094
1925	On systems that do not implement C<mprotect>, this function returns	2095	On systems that do not implement C<mprotect>, this function returns
1926	ENOSYS, otherwise the return value of C<mprotect>.	2096	ENOSYS, otherwise the return value of C<mprotect>.
1927		2097
1928	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2098	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1929		2099
1930	Memory-maps a file (or anonymous memory range) and attaches it to the	2100	Memory-maps a file (or anonymous memory range) and attaches it to the
1931	given C<$scalar>, which will act like a string scalar. Returns true on	2101	given C<$scalar>, which will act like a string scalar. Returns true on
1932	success, and false otherwise.	2102	success, and false otherwise.
1933		2103
		2104	The scalar must exist, but its contents do not matter - this means you
		2105	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2106	the scalar first.
		2107
1934	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2108	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1935	change the string length, and most read-only operations such as copying it	2109	which don't change the string length, and most read-only operations such
1936	or searching it with regexes and so on.	2110	as copying it or searching it with regexes and so on.
1937		2111
1938	Anything else is unsafe and will, at best, result in memory leaks.	2112	Anything else is unsafe and will, at best, result in memory leaks.
1939		2113
1940	The memory map associated with the C<$scalar> is automatically removed	2114	The memory map associated with the C<$scalar> is automatically removed
1941	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2115	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1942	C<IO::AIO::munmap> functions are called.	2116	or C<IO::AIO::munmap> functions are called on it.
1943		2117
1944	This calls the C<mmap>(2) function internally. See your system's manual	2118	This calls the C<mmap>(2) function internally. See your system's manual
1945	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2119	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1946		2120
1947	The C<$length> must be larger than zero and smaller than the actual	2121	The C<$length> must be larger than zero and smaller than the actual
1948	filesize.	2122	filesize.
1949		2123
1950	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2124	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1951	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2125	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1952		2126
1953	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2127	C<$flags> can be a combination of
1954	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2128	C<IO::AIO::MAP_SHARED> or
1955	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2129	C<IO::AIO::MAP_PRIVATE>,
		2130	or a number of system-specific flags (when not available, the are C<0>):
1956	(which is set to C<MAP_ANON> if your system only provides this	2131	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1957	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2132	C<IO::AIO::MAP_LOCKED>,
1958	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2133	C<IO::AIO::MAP_NORESERVE>,
		2134	C<IO::AIO::MAP_POPULATE>,
1959	C<IO::AIO::MAP_NONBLOCK>	2135	C<IO::AIO::MAP_NONBLOCK>,
		2136	C<IO::AIO::MAP_FIXED>,
		2137	C<IO::AIO::MAP_GROWSDOWN>,
		2138	C<IO::AIO::MAP_32BIT>,
		2139	C<IO::AIO::MAP_HUGETLB> or
		2140	C<IO::AIO::MAP_STACK>.
1960		2141
1961	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2142	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1962		2143
1963	C<$offset> is the offset from the start of the file - it generally must be	2144	C<$offset> is the offset from the start of the file - it generally must be
1964	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2145	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1977	my $fast_md5 = md5 $data;	2158	my $fast_md5 = md5 $data;
1978		2159
1979	=item IO::AIO::munmap $scalar	2160	=item IO::AIO::munmap $scalar
1980		2161
1981	Removes a previous mmap and undefines the C<$scalar>.	2162	Removes a previous mmap and undefines the C<$scalar>.
		2163
		2164	=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
		2165
		2166	Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
		2167	been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
		2168	C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
		2169
		2170	Returns true if successful, and false otherwise. If the underlying mmapped
		2171	region has changed address, then the true value has the numerical value
		2172	C<1>, otherwise it has the numerical value C<0>:
		2173
		2174	my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
		2175	or die "mremap: $!";
		2176
		2177	if ($success*1) {
		2178	warn "scalar has chanegd address in memory\n";
		2179	}
		2180
		2181	C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
		2182	implemented, but not supported and might go away in a future version.
		2183
		2184	On systems where this call is not supported or is not emulated, this call
		2185	returns falls and sets C<$!> to C<ENOSYS>.
1982		2186
1983	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef	2187	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1984		2188
1985	Calls the C<munlock> function, undoing the effects of a previous	2189	Calls the C<munlock> function, undoing the effects of a previous
1986	C<aio_mlock> call (see its description for details).	2190	C<aio_mlock> call (see its description for details).
…		…
2007		2211
2008	See the C<splice(2)> manpage for details.	2212	See the C<splice(2)> manpage for details.
2009		2213
2010	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags	2214	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2011		2215
2012	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the	2216	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2013	description for C<IO::AIO::splice> above for details.	2217	description for C<IO::AIO::splice> above for details.
		2218
		2219	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2220
		2221	Attempts to query or change the pipe buffer size. Obviously works only
		2222	on pipes, and currently works only on GNU/Linux systems, and fails with
		2223	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2224	size on other systems, drop me a note.
		2225
		2226	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2227
		2228	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2229	C<$flags> is missing or C<0>, then this should be the same as a call to
		2230	perl's built-in C<pipe> function and create a new pipe, and works on
		2231	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2232	(..., 4096, O_BINARY)>.
		2233
		2234	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2235	the given flags (Linux 2.6.27, glibc 2.9).
		2236
		2237	On success, the read and write file handles are returned.
		2238
		2239	On error, nothing will be returned. If the pipe2 syscall is missing and
		2240	C<$flags> is non-zero, fails with C<ENOSYS>.
		2241
		2242	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2243	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2244	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2245
		2246	Example: create a pipe race-free w.r.t. threads and fork:
		2247
		2248	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2249	or die "pipe2: $!\n";
		2250
		2251	=item $fh = IO::AIO::eventfd [$initval, [$flags]]
		2252
		2253	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2254	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2255
		2256	On success, the new eventfd filehandle is returned, otherwise returns
		2257	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2258
		2259	Please refer to L<eventfd(2)> for more info on this call.
		2260
		2261	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2262	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
		2263
		2264	Example: create a new eventfd filehandle:
		2265
		2266	$fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
		2267	or die "eventfd: $!\n";
		2268
		2269	=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
		2270
		2271	This is a direct interface to the Linux L<timerfd_create(2)> system call. The
		2272	(unhelpful) default for C<$flags> is C<0>.
		2273
		2274	On success, the new timerfd filehandle is returned, otherwise returns
		2275	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2276
		2277	Please refer to L<timerfd_create(2)> for more info on this call.
		2278
		2279	The following C<$clockid> values are
		2280	available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
		2281	C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
		2282	C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
		2283	C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
		2284
		2285	The following C<$flags> values are available (Linux
		2286	2.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
		2287
		2288	Example: create a new timerfd and set it to one-second repeated alarms,
		2289	then wait for two alarms:
		2290
		2291	my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
		2292	or die "timerfd_create: $!\n";
		2293
		2294	defined IO::AIO::timerfd_settime $fh, 0, 1, 1
		2295	or die "timerfd_settime: $!\n";
		2296
		2297	for (1..2) {
		2298	8 == sysread $fh, my $buf, 8
		2299	or die "timerfd read failure\n";
		2300
		2301	printf "number of expirations (likely 1): %d\n",
		2302	unpack "Q", $buf;
		2303	}
		2304
		2305	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
		2306
		2307	This is a direct interface to the Linux L<timerfd_settime(2)> system
		2308	call. Please refer to its manpage for more info on this call.
		2309
		2310	The new itimerspec is specified using two (possibly fractional) second
		2311	values, C<$new_interval> and C<$new_value>).
		2312
		2313	On success, the current interval and value are returned (as per
		2314	C<timerfd_gettime>). On failure, the empty list is returned.
		2315
		2316	The following C<$flags> values are
		2317	available: C<IO::AIO::TFD_TIMER_ABSTIME> and
		2318	C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
		2319
		2320	See C<IO::AIO::timerfd_create> for a full example.
		2321
		2322	=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
		2323
		2324	This is a direct interface to the Linux L<timerfd_gettime(2)> system
		2325	call. Please refer to its manpage for more info on this call.
		2326
		2327	On success, returns the current values of interval and value for the given
		2328	timerfd (as potentially fractional second values). On failure, the empty
		2329	list is returned.
2014		2330
2015	=back	2331	=back
2016		2332
2017	=cut	2333	=cut
2018		2334
…		…
2084	the process will result in undefined behaviour. Calling it at any time	2400	the process will result in undefined behaviour. Calling it at any time
2085	will also result in any undefined (by POSIX) behaviour.	2401	will also result in any undefined (by POSIX) behaviour.
2086		2402
2087	=back	2403	=back
2088		2404
		2405	=head2 LINUX-SPECIFIC CALLS
		2406
		2407	When a call is documented as "linux-specific" then this means it
		2408	originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
		2409	availability and compatibility of such calls regardless of the platform
		2410	it is compiled on, so platforms such as FreeBSD which often implement
		2411	these calls will work. When in doubt, call them and see if they fail wth
		2412	C<ENOSYS>.
		2413
2089	=head2 MEMORY USAGE	2414	=head2 MEMORY USAGE
2090		2415
2091	Per-request usage:	2416	Per-request usage:
2092		2417
2093	Each aio request uses - depending on your architecture - around 100-200	2418	Each aio request uses - depending on your architecture - around 100-200
…		…
2105	temporary buffers, and each thread requires a stack and other data	2430	temporary buffers, and each thread requires a stack and other data
2106	structures (usually around 16k-128k, depending on the OS).	2431	structures (usually around 16k-128k, depending on the OS).
2107		2432
2108	=head1 KNOWN BUGS	2433	=head1 KNOWN BUGS
2109		2434
2110	Known bugs will be fixed in the next release.	2435	Known bugs will be fixed in the next release :)
		2436
		2437	=head1 KNOWN ISSUES
		2438
		2439	Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
		2440	or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
		2441	non-created hash slots or other scalars I didn't think of. It's best to
		2442	avoid such and either use scalar variables or making sure that the scalar
		2443	exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
		2444
		2445	I am not sure anything can be done about this, so this is considered a
		2446	known issue, rather than a bug.
2111		2447
2112	=head1 SEE ALSO	2448	=head1 SEE ALSO
2113		2449
2114	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a	2450	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2115	more natural syntax.	2451	more natural syntax.

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.231 by root, Fri Jul 27 19:03:18 2012 UTC vs. Revision 1.287 by root, Tue Jul 24 04:58:59 2018 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.231 by root, Fri Jul 27 19:03:18 2012 UTC vs.
Revision 1.287 by root, Tue Jul 24 04:58:59 2018 UTC