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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.220 by root, Sun Apr 1 17:46:02 2012 UTC vs.
Revision 1.281 by root, Tue Feb 20 04:32:59 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 = '4.13';	176	our $VERSION = 4.4;
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	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
…		…
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
277	IO::AIO::madvise $scalar, $offset, $length, $advice	290	IO::AIO::madvise $scalar, $offset, $length, $advice
278	IO::AIO::mprotect $scalar, $offset, $length, $protect	291	IO::AIO::mprotect $scalar, $offset, $length, $protect
279	IO::AIO::munlock $scalar, $offset = 0, $length = undef	292	IO::AIO::munlock $scalar, $offset = 0, $length = undef
280	IO::AIO::munlockall	293	IO::AIO::munlockall
281		294
…		…
358		371
359		372
360	=item aio_open $pathname, $flags, $mode, $callback->($fh)	373	=item aio_open $pathname, $flags, $mode, $callback->($fh)
361		374
362	Asynchronously open or create a file and call the callback with a newly	375	Asynchronously open or create a file and call the callback with a newly
363	created filehandle for the file.	376	created filehandle for the file (or C<undef> in case of an error).
364		377
365	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	378	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
366	for an explanation.	379	for an explanation.
367		380
368	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	381	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
391	following POSIX and non-POSIX constants are available (missing ones on	404	following POSIX and non-POSIX constants are available (missing ones on
392	your system are, as usual, C<0>):	405	your system are, as usual, C<0>):
393		406
394	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	407	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>,	408	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>.	409	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
397		410
398		411
399	=item aio_close $fh, $callback->($status)	412	=item aio_close $fh, $callback->($status)
400		413
401	Asynchronously close a file and call the callback with the result	414	Asynchronously close a file and call the callback with the result
…		…
413		426
414	=cut	427	=cut
415		428
416	=item aio_seek $fh, $offset, $whence, $callback->($offs)	429	=item aio_seek $fh, $offset, $whence, $callback->($offs)
417		430
418	Seeks the filehandle to the new C<$offset>, similarly to perl'S	431	Seeks the filehandle to the new C<$offset>, similarly to perl's
419	C<sysseek>. The C<$whence> can use the traditional values (C<0> for	432	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
420	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for	433	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
421	C<IO::AIO::SEEK_END>).	434	C<IO::AIO::SEEK_END>).
422		435
423	The resulting absolute offset will be passed to the callback, or C<-1> in	436	The resulting absolute offset will be passed to the callback, or C<-1> in
…		…
425		438
426	In theory, the C<$whence> constants could be different than the	439	In theory, the C<$whence> constants could be different than the
427	corresponding values from L<Fcntl>, but perl guarantees they are the same,	440	corresponding values from L<Fcntl>, but perl guarantees they are the same,
428	so don't panic.	441	so don't panic.
429		442
		443	As a GNU/Linux (and maybe Solaris) extension, also the constants
		444	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		445	could be found. No guarantees about suitability for use in C<aio_seek> or
		446	Perl's C<sysseek> can be made though, although I would naively assume they
		447	"just work".
		448
430	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	449	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
431		450
432	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	451	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
433		452
434	Reads or writes C<$length> bytes from or to the specified C<$fh> and	453	Reads or writes C<$length> bytes from or to the specified C<$fh> and
435	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	454	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
436	and calls the callback without the actual number of bytes read (or -1 on	455	calls the callback with the actual number of bytes transferred (or -1 on
437	error, just like the syscall).	456	error, just like the syscall).
438		457
439	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	458	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
440	offset plus the actual number of bytes read.	459	offset plus the actual number of bytes read.
441		460
…		…
499	As native sendfile syscalls (as practically any non-POSIX interface hacked	518	As native sendfile syscalls (as practically any non-POSIX interface hacked
500	together in a hurry to improve benchmark numbers) tend to be rather buggy	519	together in a hurry to improve benchmark numbers) tend to be rather buggy
501	on many systems, this implementation tries to work around some known bugs	520	on many systems, this implementation tries to work around some known bugs
502	in Linux and FreeBSD kernels (probably others, too), but that might fail,	521	in Linux and FreeBSD kernels (probably others, too), but that might fail,
503	so you really really should check the return value of C<aio_sendfile> -	522	so you really really should check the return value of C<aio_sendfile> -
504	fewre bytes than expected might have been transferred.	523	fewer bytes than expected might have been transferred.
505		524
506		525
507	=item aio_readahead $fh,$offset,$length, $callback->($retval)	526	=item aio_readahead $fh,$offset,$length, $callback->($retval)
508		527
509	C<aio_readahead> populates the page cache with data from a file so that	528	C<aio_readahead> populates the page cache with data from a file so that
…		…
513	whole pages, so that offset is effectively rounded down to a page boundary	532	whole pages, so that offset is effectively rounded down to a page boundary
514	and bytes are read up to the next page boundary greater than or equal to	533	and bytes are read up to the next page boundary greater than or equal to
515	(off-set+length). C<aio_readahead> does not read beyond the end of the	534	(off-set+length). C<aio_readahead> does not read beyond the end of the
516	file. The current file offset of the file is left unchanged.	535	file. The current file offset of the file is left unchanged.
517		536
518	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	537	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
519	emulated by simply reading the data, which would have a similar effect.	538	be emulated by simply reading the data, which would have a similar effect.
520		539
521		540
522	=item aio_stat $fh_or_path, $callback->($status)	541	=item aio_stat $fh_or_path, $callback->($status)
523		542
524	=item aio_lstat $fh, $callback->($status)	543	=item aio_lstat $fh, $callback->($status)
…		…
593	namemax => 255,	612	namemax => 255,
594	frsize => 1024,	613	frsize => 1024,
595	fsid => 1810	614	fsid => 1810
596	}	615	}
597		616
598
599	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	617	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
600		618
601	Works like perl's C<utime> function (including the special case of $atime	619	Works like perl's C<utime> function (including the special case of $atime
602	and $mtime being undef). Fractional times are supported if the underlying	620	and $mtime being undef). Fractional times are supported if the underlying
603	syscalls support them.	621	syscalls support them.
…		…
630	=item aio_truncate $fh_or_path, $offset, $callback->($status)	648	=item aio_truncate $fh_or_path, $offset, $callback->($status)
631		649
632	Works like truncate(2) or ftruncate(2).	650	Works like truncate(2) or ftruncate(2).
633		651
634		652
		653	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		654
		655	Allocates or frees disk space according to the C<$mode> argument. See the
		656	linux C<fallocate> documentation for details.
		657
		658	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		659	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		660	to deallocate a file range.
		661
		662	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		663	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		664	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		665	to unshare shared blocks (see your L<fallocate(2)> manpage).
		666
		667	The file system block size used by C<fallocate> is presumably the
		668	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		669	can dictate other limitations.
		670
		671	If C<fallocate> isn't available or cannot be emulated (currently no
		672	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		673
		674
635	=item aio_chmod $fh_or_path, $mode, $callback->($status)	675	=item aio_chmod $fh_or_path, $mode, $callback->($status)
636		676
637	Works like perl's C<chmod> function.	677	Works like perl's C<chmod> function.
638		678
639		679
…		…
676		716
677		717
678	=item aio_realpath $pathname, $callback->($path)	718	=item aio_realpath $pathname, $callback->($path)
679		719
680	Asynchronously make the path absolute and resolve any symlinks in	720	Asynchronously make the path absolute and resolve any symlinks in
681	C<$path>. The resulting path only consists of directories (Same as	721	C<$path>. The resulting path only consists of directories (same as
682	L<Cwd::realpath>).	722	L<Cwd::realpath>).
683		723
684	This request can be used to get the absolute path of the current working	724	This request can be used to get the absolute path of the current working
685	directory by passing it a path of F<.> (a single dot).	725	directory by passing it a path of F<.> (a single dot).
686		726
687		727
688	=item aio_rename $srcpath, $dstpath, $callback->($status)	728	=item aio_rename $srcpath, $dstpath, $callback->($status)
689		729
690	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	730	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
691	rename(2) and call the callback with the result code.	731	rename(2) and call the callback with the result code.
		732
		733	On systems that support the AIO::WD working directory abstraction
		734	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		735	of failing, C<rename> is called on the absolute path of C<$wd>.
		736
		737
		738	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		739
		740	Basically a version of C<aio_rename> with an additional C<$flags>
		741	argument. Calling this with C<$flags=0> is the same as calling
		742	C<aio_rename>.
		743
		744	Non-zero flags are currently only supported on GNU/Linux systems that
		745	support renameat2. Other systems fail with C<ENOSYS> in this case.
		746
		747	The following constants are available (missing ones are, as usual C<0>),
		748	see renameat2(2) for details:
		749
		750	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		751	and C<IO::AIO::RENAME_WHITEOUT>.
692		752
693		753
694	=item aio_mkdir $pathname, $mode, $callback->($status)	754	=item aio_mkdir $pathname, $mode, $callback->($status)
695		755
696	Asynchronously mkdir (create) a directory and call the callback with	756	Asynchronously mkdir (create) a directory and call the callback with
…		…
700		760
701	=item aio_rmdir $pathname, $callback->($status)	761	=item aio_rmdir $pathname, $callback->($status)
702		762
703	Asynchronously rmdir (delete) a directory and call the callback with the	763	Asynchronously rmdir (delete) a directory and call the callback with the
704	result code.	764	result code.
		765
		766	On systems that support the AIO::WD working directory abstraction
		767	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		768	C<rmdir> is called on the absolute path of C<$wd>.
705		769
706		770
707	=item aio_readdir $pathname, $callback->($entries)	771	=item aio_readdir $pathname, $callback->($entries)
708		772
709	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	773	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
…		…
778	C<$type>'s are known, which can be used to speed up some algorithms.	842	C<$type>'s are known, which can be used to speed up some algorithms.
779		843
780	=back	844	=back
781		845
782		846
		847	=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
		848
		849	Opens, reads and closes the given file. The data is put into C<$data>,
		850	which is resized as required.
		851
		852	If C<$offset> is negative, then it is counted from the end of the file.
		853
		854	If C<$length> is zero, then the remaining length of the file is
		855	used. Also, in this case, the same limitations to modifying C<$data> apply
		856	as when IO::AIO::mmap is used, i.e. it must only be modified in-place
		857	with C<substr>. If the size of the file is known, specifying a non-zero
		858	C<$length> results in a performance advantage.
		859
		860	This request is similar to the older C<aio_load> request, but since it is
		861	a single request, it might be more efficient to use.
		862
		863	Example: load F</etc/passwd> into C<$passwd>.
		864
		865	my $passwd;
		866	aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
		867	$_[0] >= 0
		868	or die "/etc/passwd: $!\n";
		869
		870	printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
		871	print $passwd;
		872	};
		873	IO::AIO::flush;
		874
		875
783	=item aio_load $pathname, $data, $callback->($status)	876	=item aio_load $pathname, $data, $callback->($status)
784		877
785	This is a composite request that tries to fully load the given file into	878	This is a composite request that tries to fully load the given file into
786	memory. Status is the same as with aio_read.	879	memory. Status is the same as with aio_read.
		880
		881	Using C<aio_slurp> might be more efficient, as it is a single request.
787		882
788	=cut	883	=cut
789		884
790	sub aio_load($$;$) {	885	sub aio_load($$;$) {
791	my ($path, undef, $cb) = @_;	886	my ($path, undef, $cb) = @_;
…		…
811	=item aio_copy $srcpath, $dstpath, $callback->($status)	906	=item aio_copy $srcpath, $dstpath, $callback->($status)
812		907
813	Try to copy the I<file> (directories not supported as either source or	908	Try to copy the I<file> (directories not supported as either source or
814	destination) from C<$srcpath> to C<$dstpath> and call the callback with	909	destination) from C<$srcpath> to C<$dstpath> and call the callback with
815	a status of C<0> (ok) or C<-1> (error, see C<$!>).	910	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		911
		912	Existing destination files will be truncated.
816		913
817	This is a composite request that creates the destination file with	914	This is a composite request that creates the destination file with
818	mode 0200 and copies the contents of the source file into it using	915	mode 0200 and copies the contents of the source file into it using
819	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	916	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
820	uid/gid, in that order.	917	uid/gid, in that order.
…		…
930	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1027	Scans a directory (similar to C<aio_readdir>) but additionally tries to
931	efficiently separate the entries of directory C<$path> into two sets of	1028	efficiently separate the entries of directory C<$path> into two sets of
932	names, directories you can recurse into (directories), and ones you cannot	1029	names, directories you can recurse into (directories), and ones you cannot
933	recurse into (everything else, including symlinks to directories).	1030	recurse into (everything else, including symlinks to directories).
934		1031
935	C<aio_scandir> is a composite request that creates of many sub requests_	1032	C<aio_scandir> is a composite request that generates many sub requests.
936	C<$maxreq> specifies the maximum number of outstanding aio requests that	1033	C<$maxreq> specifies the maximum number of outstanding aio requests that
937	this function generates. If it is C<< <= 0 >>, then a suitable default	1034	this function generates. If it is C<< <= 0 >>, then a suitable default
938	will be chosen (currently 4).	1035	will be chosen (currently 4).
939		1036
940	On error, the callback is called without arguments, otherwise it receives	1037	On error, the callback is called without arguments, otherwise it receives
…		…
1074	}	1171	}
1075		1172
1076	=item aio_rmtree $pathname, $callback->($status)	1173	=item aio_rmtree $pathname, $callback->($status)
1077		1174
1078	Delete a directory tree starting (and including) C<$path>, return the	1175	Delete a directory tree starting (and including) C<$path>, return the
1079	status of the final C<rmdir> only. This is a composite request that	1176	status of the final C<rmdir> only. This is a composite request that
1080	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1177	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1081	everything else.	1178	everything else.
1082		1179
1083	=cut	1180	=cut
1084		1181
…		…
1105	add $grp $dirgrp;	1202	add $grp $dirgrp;
1106	};	1203	};
1107		1204
1108	$grp	1205	$grp
1109	}	1206	}
		1207
		1208	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1209
		1210	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1211
		1212	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1213	they execute asynchronously and pass the return value to the callback.
		1214
		1215	Both calls can be used for a lot of things, some of which make more sense
		1216	to run asynchronously in their own thread, while some others make less
		1217	sense. For example, calls that block waiting for external events, such
		1218	as locking, will also lock down an I/O thread while it is waiting, which
		1219	can deadlock the whole I/O system. At the same time, there might be no
		1220	alternative to using a thread to wait.
		1221
		1222	So in general, you should only use these calls for things that do
		1223	(filesystem) I/O, not for things that wait for other events (network,
		1224	other processes), although if you are careful and know what you are doing,
		1225	you still can.
		1226
		1227	The following constants are available (missing ones are, as usual C<0>):
		1228
		1229	C<F_DUPFD_CLOEXEC>,
		1230
		1231	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1232
		1233	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1234
		1235	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1236	C<FS_IOC_FIEMAP>.
		1237
		1238	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1239	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1240
		1241	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1242	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1243	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1244	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1245	C<FS_FL_USER_MODIFIABLE>.
		1246
		1247	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1248	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1249	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1250	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1110		1251
1111	=item aio_sync $callback->($status)	1252	=item aio_sync $callback->($status)
1112		1253
1113	Asynchronously call sync and call the callback when finished.	1254	Asynchronously call sync and call the callback when finished.
1114		1255
…		…
1183	};	1324	};
1184		1325
1185	$grp	1326	$grp
1186	}	1327	}
1187		1328
1188	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1329	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1189		1330
1190	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1331	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1191	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1332	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1192	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1333	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1193	scalar must only be modified in-place while an aio operation is pending on	1334	scalar must only be modified in-place while an aio operation is pending on
…		…
1195		1336
1196	It calls the C<msync> function of your OS, if available, with the memory	1337	It calls the C<msync> function of your OS, if available, with the memory
1197	area starting at C<$offset> in the string and ending C<$length> bytes	1338	area starting at C<$offset> in the string and ending C<$length> bytes
1198	later. If C<$length> is negative, counts from the end, and if C<$length>	1339	later. If C<$length> is negative, counts from the end, and if C<$length>
1199	is C<undef>, then it goes till the end of the string. The flags can be	1340	is C<undef>, then it goes till the end of the string. The flags can be
1200	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1341	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1201	C<IO::AIO::MS_SYNC>.	1342	C<IO::AIO::MS_INVALIDATE>.
1202		1343
1203	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1344	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1204		1345
1205	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1346	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1206	scalars.	1347	scalars.
1207		1348
1208	It touches (reads or writes) all memory pages in the specified	1349	It touches (reads or writes) all memory pages in the specified
1209	range inside the scalar. All caveats and parameters are the same	1350	range inside the scalar. All caveats and parameters are the same
1210	as for C<aio_msync>, above, except for flags, which must be either	1351	as for C<aio_msync>, above, except for flags, which must be either
1211	C<0> (which reads all pages and ensures they are instantiated) or	1352	C<0> (which reads all pages and ensures they are instantiated) or
1212	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1353	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1213	writing an octet from it, which dirties the page).	1354	writing an octet from it, which dirties the page).
1214		1355
1215	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1356	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1216		1357
1217	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1358	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1248	documented under L<MISCELLANEOUS FUNCTIONS>.	1389	documented under L<MISCELLANEOUS FUNCTIONS>.
1249		1390
1250	Example: asynchronously lock all current and future pages into memory.	1391	Example: asynchronously lock all current and future pages into memory.
1251		1392
1252	aio_mlockall IO::AIO::MCL_FUTURE;	1393	aio_mlockall IO::AIO::MCL_FUTURE;
		1394
		1395	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1396
		1397	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1398	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1399	the ioctl is not available on your OS, then this request will fail with
		1400	C<ENOSYS>.
		1401
		1402	C<$start> is the starting offset to query extents for, C<$length> is the
		1403	size of the range to query - if it is C<undef>, then the whole file will
		1404	be queried.
		1405
		1406	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1407	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1408	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1409	the data portion.
		1410
		1411	C<$count> is the maximum number of extent records to return. If it is
		1412	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1413	case, if it is C<0>, then the callback receives the number of extents
		1414	instead of the extents themselves (which is unreliable, see below).
		1415
		1416	If an error occurs, the callback receives no arguments. The special
		1417	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1418
		1419	Otherwise, the callback receives an array reference with extent
		1420	structures. Each extent structure is an array reference itself, with the
		1421	following members:
		1422
		1423	[$logical, $physical, $length, $flags]
		1424
		1425	Flags is any combination of the following flag values (typically either C<0>
		1426	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1427
		1428	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1429	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1430	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1431	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1432	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1433	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1434
		1435	At the time of this writing (Linux 3.2), this request is unreliable unless
		1436	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1437	it to return all extents of a range for files with a large number of
		1438	extents. The code (only) works around all these issues if C<$count> is
		1439	C<undef>.
1253		1440
1254	=item aio_group $callback->(...)	1441	=item aio_group $callback->(...)
1255		1442
1256	This is a very special aio request: Instead of doing something, it is a	1443	This is a very special aio request: Instead of doing something, it is a
1257	container for other aio requests, which is useful if you want to bundle	1444	container for other aio requests, which is useful if you want to bundle
…		…
1341	aio_stat [$etcdir, "passwd"], sub {	1528	aio_stat [$etcdir, "passwd"], sub {
1342	# yay	1529	# yay
1343	};	1530	};
1344	};	1531	};
1345		1532
1346	That C<aio_wd> is a request and not a normal function shows that creating	1533	The fact that C<aio_wd> is a request and not a normal function shows that
1347	an IO::AIO::WD object is itself a potentially blocking operation, which is	1534	creating an IO::AIO::WD object is itself a potentially blocking operation,
1348	why it is done asynchronously.	1535	which is why it is done asynchronously.
1349		1536
1350	To stat the directory obtained with C<aio_wd> above, one could write	1537	To stat the directory obtained with C<aio_wd> above, one could write
1351	either of the following three request calls:	1538	either of the following three request calls:
1352		1539
1353	aio_lstat "/etc" , sub { ... # pathname as normal string	1540	aio_lstat "/etc" , sub { ... # pathname as normal string
…		…
1370	There are some caveats: when directories get renamed (or deleted), the	1557	There are some caveats: when directories get renamed (or deleted), the
1371	pathname string doesn't change, so will point to the new directory (or	1558	pathname string doesn't change, so will point to the new directory (or
1372	nowhere at all), while the directory fd, if available on the system,	1559	nowhere at all), while the directory fd, if available on the system,
1373	will still point to the original directory. Most functions accepting a	1560	will still point to the original directory. Most functions accepting a
1374	pathname will use the directory fd on newer systems, and the string on	1561	pathname will use the directory fd on newer systems, and the string on
1375	older systems. Some functions (such as realpath) will always rely on the	1562	older systems. Some functions (such as C<aio_realpath>) will always rely on
1376	string form of the pathname.	1563	the string form of the pathname.
1377		1564
1378	So this fucntionality is mainly useful to get some protection against	1565	So this functionality is mainly useful to get some protection against
1379	C<chdir>, to easily get an absolute path out of a relative path for future	1566	C<chdir>, to easily get an absolute path out of a relative path for future
1380	reference, and to speed up doing many operations in the same directory	1567	reference, and to speed up doing many operations in the same directory
1381	(e.g. when stat'ing all files in a directory).	1568	(e.g. when stat'ing all files in a directory).
1382		1569
1383	The following functions implement this working directory abstraction:	1570	The following functions implement this working directory abstraction:
…		…
1396	passing C<undef> as working directory component of a pathname fails the	1583	passing C<undef> as working directory component of a pathname fails the
1397	request with C<ENOENT>, there is often no need for error checking in the	1584	request with C<ENOENT>, there is often no need for error checking in the
1398	C<aio_wd> callback, as future requests using the value will fail in the	1585	C<aio_wd> callback, as future requests using the value will fail in the
1399	expected way.	1586	expected way.
1400		1587
1401	If this call isn't available because your OS lacks it or it couldn't be
1402	detected, it will be emulated by calling C<fsync> instead.
1403
1404	=item IO::AIO::CWD	1588	=item IO::AIO::CWD
1405		1589
1406	This is a compiletime constant (object) that represents the process	1590	This is a compiletime constant (object) that represents the process
1407	current working directory.	1591	current working directory.
1408		1592
1409	Specifying this object as working directory object for a pathname is as	1593	Specifying this object as working directory object for a pathname is as if
1410	if the pathname would be specified directly, without a directory object,	1594	the pathname would be specified directly, without a directory object. For
1411	e.g., these calls are functionally identical:	1595	example, these calls are functionally identical:
1412		1596
1413	aio_stat "somefile", sub { ... };	1597	aio_stat "somefile", sub { ... };
1414	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };	1598	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1415		1599
1416	=back	1600	=back
1417		1601
		1602	To recover the path associated with an IO::AIO::WD object, you can use
		1603	C<aio_realpath>:
		1604
		1605	aio_realpath $wd, sub {
		1606	warn "path is $_[0]\n";
		1607	};
		1608
		1609	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1610	sometimes, fall back to using an absolue path.
1418		1611
1419	=head2 IO::AIO::REQ CLASS	1612	=head2 IO::AIO::REQ CLASS
1420		1613
1421	All non-aggregate C<aio_*> functions return an object of this class when	1614	All non-aggregate C<aio_*> functions return an object of this class when
1422	called in non-void context.	1615	called in non-void context.
…		…
1600		1793
1601	See C<poll_cb> for an example.	1794	See C<poll_cb> for an example.
1602		1795
1603	=item IO::AIO::poll_cb	1796	=item IO::AIO::poll_cb
1604		1797
1605	Process some outstanding events on the result pipe. You have to call	1798	Process some requests that have reached the result phase (i.e. they have
		1799	been executed but the results are not yet reported). You have to call
		1800	this "regularly" to finish outstanding requests.
		1801
1606	this regularly. Returns C<0> if all events could be processed (or there	1802	Returns C<0> if all events could be processed (or there were no
1607	were no events to process), or C<-1> if it returned earlier for whatever	1803	events to process), or C<-1> if it returned earlier for whatever
1608	reason. Returns immediately when no events are outstanding. The amount of	1804	reason. Returns immediately when no events are outstanding. The amount
1609	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1805	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1610	C<IO::AIO::max_poll_time>.	1806	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1611		1807
1612	If not all requests were processed for whatever reason, the filehandle	1808	If not all requests were processed for whatever reason, the poll file
1613	will still be ready when C<poll_cb> returns, so normally you don't have to	1809	descriptor will still be ready when C<poll_cb> returns, so normally you
1614	do anything special to have it called later.	1810	don't have to do anything special to have it called later.
1615		1811
1616	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1812	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1617	ready, it can be beneficial to call this function from loops which submit	1813	ready, it can be beneficial to call this function from loops which submit
1618	a lot of requests, to make sure the results get processed when they become	1814	a lot of requests, to make sure the results get processed when they become
1619	available and not just when the loop is finished and the event loop takes	1815	available and not just when the loop is finished and the event loop takes
…		…
1628	poll => 'r', async => 1,	1824	poll => 'r', async => 1,
1629	cb => \&IO::AIO::poll_cb);	1825	cb => \&IO::AIO::poll_cb);
1630		1826
1631	=item IO::AIO::poll_wait	1827	=item IO::AIO::poll_wait
1632		1828
1633	If there are any outstanding requests and none of them in the result	1829	Wait until either at least one request is in the result phase or no
1634	phase, wait till the result filehandle becomes ready for reading (simply	1830	requests are outstanding anymore.
1635	does a C<select> on the filehandle. This is useful if you want to	1831
1636	synchronously wait for some requests to finish).	1832	This is useful if you want to synchronously wait for some requests to
		1833	become ready, without actually handling them.
1637		1834
1638	See C<nreqs> for an example.	1835	See C<nreqs> for an example.
1639		1836
1640	=item IO::AIO::poll	1837	=item IO::AIO::poll
1641		1838
…		…
1762		1959
1763	This is a very bad function to use in interactive programs because it	1960	This is a very bad function to use in interactive programs because it
1764	blocks, and a bad way to reduce concurrency because it is inexact: Better	1961	blocks, and a bad way to reduce concurrency because it is inexact: Better
1765	use an C<aio_group> together with a feed callback.	1962	use an C<aio_group> together with a feed callback.
1766		1963
1767	It's main use is in scripts without an event loop - when you want to stat	1964	Its main use is in scripts without an event loop - when you want to stat
1768	a lot of files, you can write somehting like this:	1965	a lot of files, you can write something like this:
1769		1966
1770	IO::AIO::max_outstanding 32;	1967	IO::AIO::max_outstanding 32;
1771		1968
1772	for my $path (...) {	1969	for my $path (...) {
1773	aio_stat $path , ...;	1970	aio_stat $path , ...;
…		…
1812		2009
1813	=back	2010	=back
1814		2011
1815	=head3 MISCELLANEOUS FUNCTIONS	2012	=head3 MISCELLANEOUS FUNCTIONS
1816		2013
1817	IO::AIO implements some functions that might be useful, but are not	2014	IO::AIO implements some functions that are useful when you want to use
1818	asynchronous.	2015	some "Advanced I/O" function not available to in Perl, without going the
		2016	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2017	counterpart.
1819		2018
1820	=over 4	2019	=over 4
		2020
		2021	=item $numfd = IO::AIO::get_fdlimit
		2022
		2023	This function is I<EXPERIMENTAL> and subject to change.
		2024
		2025	Tries to find the current file descriptor limit and returns it, or
		2026	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2027	the highest valid file descriptor number.
		2028
		2029	=item IO::AIO::min_fdlimit [$numfd]
		2030
		2031	This function is I<EXPERIMENTAL> and subject to change.
		2032
		2033	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2034	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2035	is missing, it will try to set a very high limit, although this is not
		2036	recommended when you know the actual minimum that you require.
		2037
		2038	If the limit cannot be raised enough, the function makes a best-effort
		2039	attempt to increase the limit as much as possible, using various
		2040	tricks, while still failing. You can query the resulting limit using
		2041	C<IO::AIO::get_fdlimit>.
		2042
		2043	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2044	true.
1821		2045
1822	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2046	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1823		2047
1824	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2048	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1825	but is blocking (this makes most sense if you know the input data is	2049	but is blocking (this makes most sense if you know the input data is
…		…
1842	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2066	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1843		2067
1844	Simply calls the C<posix_madvise> function (see its	2068	Simply calls the C<posix_madvise> function (see its
1845	manpage for details). The following advice constants are	2069	manpage for details). The following advice constants are
1846	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2070	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1847	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2071	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2072	C<IO::AIO::MADV_DONTNEED>.
		2073
		2074	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2075	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2076	will be reduced to fit into the C<$scalar>.
1848		2077
1849	On systems that do not implement C<posix_madvise>, this function returns	2078	On systems that do not implement C<posix_madvise>, this function returns
1850	ENOSYS, otherwise the return value of C<posix_madvise>.	2079	ENOSYS, otherwise the return value of C<posix_madvise>.
1851		2080
1852	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2081	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
…		…
1854	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2083	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1855	$scalar (see its manpage for details). The following protect	2084	$scalar (see its manpage for details). The following protect
1856	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2085	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1857	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2086	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1858		2087
		2088	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2089	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2090	will be reduced to fit into the C<$scalar>.
		2091
1859	On systems that do not implement C<mprotect>, this function returns	2092	On systems that do not implement C<mprotect>, this function returns
1860	ENOSYS, otherwise the return value of C<mprotect>.	2093	ENOSYS, otherwise the return value of C<mprotect>.
1861		2094
1862	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2095	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1863		2096
1864	Memory-maps a file (or anonymous memory range) and attaches it to the	2097	Memory-maps a file (or anonymous memory range) and attaches it to the
1865	given C<$scalar>, which will act like a string scalar.	2098	given C<$scalar>, which will act like a string scalar. Returns true on
		2099	success, and false otherwise.
1866		2100
		2101	The scalar must exist, but its contents do not matter - this means you
		2102	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2103	the scalar first.
		2104
1867	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2105	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1868	change the string length, and most read-only operations such as copying it	2106	which don't change the string length, and most read-only operations such
1869	or searching it with regexes and so on.	2107	as copying it or searching it with regexes and so on.
1870		2108
1871	Anything else is unsafe and will, at best, result in memory leaks.	2109	Anything else is unsafe and will, at best, result in memory leaks.
1872		2110
1873	The memory map associated with the C<$scalar> is automatically removed	2111	The memory map associated with the C<$scalar> is automatically removed
1874	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2112	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1875	C<IO::AIO::munmap> functions are called.	2113	or C<IO::AIO::munmap> functions are called on it.
1876		2114
1877	This calls the C<mmap>(2) function internally. See your system's manual	2115	This calls the C<mmap>(2) function internally. See your system's manual
1878	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2116	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1879		2117
1880	The C<$length> must be larger than zero and smaller than the actual	2118	The C<$length> must be larger than zero and smaller than the actual
1881	filesize.	2119	filesize.
1882		2120
1883	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2121	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1884	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2122	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1885		2123
1886	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2124	C<$flags> can be a combination of
1887	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2125	C<IO::AIO::MAP_SHARED> or
1888	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2126	C<IO::AIO::MAP_PRIVATE>,
		2127	or a number of system-specific flags (when not available, the are C<0>):
1889	(which is set to C<MAP_ANON> if your system only provides this	2128	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1890	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2129	C<IO::AIO::MAP_LOCKED>,
1891	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2130	C<IO::AIO::MAP_NORESERVE>,
		2131	C<IO::AIO::MAP_POPULATE>,
1892	C<IO::AIO::MAP_NONBLOCK>	2132	C<IO::AIO::MAP_NONBLOCK>,
		2133	C<IO::AIO::MAP_FIXED>,
		2134	C<IO::AIO::MAP_GROWSDOWN>,
		2135	C<IO::AIO::MAP_32BIT>,
		2136	C<IO::AIO::MAP_HUGETLB> or
		2137	C<IO::AIO::MAP_STACK>.
1893		2138
1894	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2139	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1895		2140
1896	C<$offset> is the offset from the start of the file - it generally must be	2141	C<$offset> is the offset from the start of the file - it generally must be
1897	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2142	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1922		2167
1923	Calls the C<munlockall> function.	2168	Calls the C<munlockall> function.
1924		2169
1925	On systems that do not implement C<munlockall>, this function returns	2170	On systems that do not implement C<munlockall>, this function returns
1926	ENOSYS, otherwise the return value of C<munlockall>.	2171	ENOSYS, otherwise the return value of C<munlockall>.
		2172
		2173	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2174
		2175	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2176	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2177	should be the file offset.
		2178
		2179	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2180	silently corrupt the data in this case.
		2181
		2182	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2183	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2184	C<IO::AIO::SPLICE_F_GIFT>.
		2185
		2186	See the C<splice(2)> manpage for details.
		2187
		2188	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2189
		2190	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2191	description for C<IO::AIO::splice> above for details.
		2192
		2193	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2194
		2195	Attempts to query or change the pipe buffer size. Obviously works only
		2196	on pipes, and currently works only on GNU/Linux systems, and fails with
		2197	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2198	size on other systems, drop me a note.
		2199
		2200	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2201
		2202	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2203	C<$flags> is missing or C<0>, then this should be the same as a call to
		2204	perl's built-in C<pipe> function and create a new pipe, and works on
		2205	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2206	(..., 4096, O_BINARY)>.
		2207
		2208	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2209	the given flags (Linux 2.6.27, glibc 2.9).
		2210
		2211	On success, the read and write file handles are returned.
		2212
		2213	On error, nothing will be returned. If the pipe2 syscall is missing and
		2214	C<$flags> is non-zero, fails with C<ENOSYS>.
		2215
		2216	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2217	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2218	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
		2219
		2220	Example: create a pipe race-free w.r.t. threads and fork:
		2221
		2222	my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
		2223	or die "pipe2: $!\n";
		2224
		2225	=item $fh = IO::AIO::eventfd ([$initval, [$flags]])
		2226
		2227	This is a direct interface to the Linux L<eventfd(2)> system call. The
		2228	(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
		2229
		2230	On success, the new eventfd filehandle is returned, otherwise returns
		2231	C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
		2232
		2233	Please refer to L<eventfd(2)> for more info on this call.
		2234
		2235	The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
		2236	C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
1927		2237
1928	=back	2238	=back
1929		2239
1930	=cut	2240	=cut
1931		2241

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.220 by root, Sun Apr 1 17:46:02 2012 UTC vs. Revision 1.281 by root, Tue Feb 20 04:32:59 2018 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.220 by root, Sun Apr 1 17:46:02 2012 UTC vs.
Revision 1.281 by root, Tue Feb 20 04:32:59 2018 UTC