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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs.
Revision 1.271 by root, Fri Jun 23 21:43:51 2017 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 = '3.93';	176	our $VERSION = 4.35;
174		177
175	our @AIO_REQ = qw(aio_sendfile 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 aio_fsync	180	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	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_wd);
185		189
186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	190	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	191	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
188	min_parallel max_parallel max_idle idle_timeout	192	min_parallel max_parallel max_idle idle_timeout
189	nreqs nready npending nthreads	193	nreqs nready npending nthreads
…		…
201		205
202	=head1 FUNCTIONS	206	=head1 FUNCTIONS
203		207
204	=head2 QUICK OVERVIEW	208	=head2 QUICK OVERVIEW
205		209
206	This section simply lists the prototypes of the most important functions	210	This section simply lists the prototypes most of the functions for
207	for quick reference. See the following sections for function-by-function	211	quick reference. See the following sections for function-by-function
208	documentation.	212	documentation.
209		213
		214	aio_wd $pathname, $callback->($wd)
210	aio_open $pathname, $flags, $mode, $callback->($fh)	215	aio_open $pathname, $flags, $mode, $callback->($fh)
211	aio_close $fh, $callback->($status)	216	aio_close $fh, $callback->($status)
		217	aio_seek $fh,$offset,$whence, $callback->($offs)
212	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	218	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	219	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
214	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	220	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
215	aio_readahead $fh,$offset,$length, $callback->($retval)	221	aio_readahead $fh,$offset,$length, $callback->($retval)
216	aio_stat $fh_or_path, $callback->($status)	222	aio_stat $fh_or_path, $callback->($status)
217	aio_lstat $fh, $callback->($status)	223	aio_lstat $fh, $callback->($status)
218	aio_statvfs $fh_or_path, $callback->($statvfs)	224	aio_statvfs $fh_or_path, $callback->($statvfs)
219	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	225	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
220	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	226	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		227	aio_chmod $fh_or_path, $mode, $callback->($status)
221	aio_truncate $fh_or_path, $offset, $callback->($status)	228	aio_truncate $fh_or_path, $offset, $callback->($status)
222	aio_chmod $fh_or_path, $mode, $callback->($status)	229	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		230	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
223	aio_unlink $pathname, $callback->($status)	231	aio_unlink $pathname, $callback->($status)
224	aio_mknod $path, $mode, $dev, $callback->($status)	232	aio_mknod $pathname, $mode, $dev, $callback->($status)
225	aio_link $srcpath, $dstpath, $callback->($status)	233	aio_link $srcpath, $dstpath, $callback->($status)
226	aio_symlink $srcpath, $dstpath, $callback->($status)	234	aio_symlink $srcpath, $dstpath, $callback->($status)
227	aio_readlink $path, $callback->($link)	235	aio_readlink $pathname, $callback->($link)
228	aio_realpath $path, $callback->($link)	236	aio_realpath $pathname, $callback->($path)
229	aio_rename $srcpath, $dstpath, $callback->($status)	237	aio_rename $srcpath, $dstpath, $callback->($status)
		238	aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
230	aio_mkdir $pathname, $mode, $callback->($status)	239	aio_mkdir $pathname, $mode, $callback->($status)
231	aio_rmdir $pathname, $callback->($status)	240	aio_rmdir $pathname, $callback->($status)
232	aio_readdir $pathname, $callback->($entries)	241	aio_readdir $pathname, $callback->($entries)
233	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	242	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
234	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	243	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
235	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	244	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		245	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
236	aio_load $path, $data, $callback->($status)	246	aio_load $pathname, $data, $callback->($status)
237	aio_copy $srcpath, $dstpath, $callback->($status)	247	aio_copy $srcpath, $dstpath, $callback->($status)
238	aio_move $srcpath, $dstpath, $callback->($status)	248	aio_move $srcpath, $dstpath, $callback->($status)
239	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
240	aio_rmtree $path, $callback->($status)	249	aio_rmtree $pathname, $callback->($status)
		250	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		251	aio_ioctl $fh, $request, $buf, $callback->($status)
241	aio_sync $callback->($status)	252	aio_sync $callback->($status)
		253	aio_syncfs $fh, $callback->($status)
242	aio_fsync $fh, $callback->($status)	254	aio_fsync $fh, $callback->($status)
243	aio_fdatasync $fh, $callback->($status)	255	aio_fdatasync $fh, $callback->($status)
244	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	256	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
245	aio_pathsync $path, $callback->($status)	257	aio_pathsync $pathname, $callback->($status)
246	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	258	aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
247	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	259	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
248	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	260	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
249	aio_mlockall $flags, $callback->($status)	261	aio_mlockall $flags, $callback->($status)
250	aio_group $callback->(...)	262	aio_group $callback->(...)
251	aio_nop $callback->()	263	aio_nop $callback->()
…		…
268	IO::AIO::nready	280	IO::AIO::nready
269	IO::AIO::npending	281	IO::AIO::npending
270		282
271	IO::AIO::sendfile $ofh, $ifh, $offset, $count	283	IO::AIO::sendfile $ofh, $ifh, $offset, $count
272	IO::AIO::fadvise $fh, $offset, $len, $advice	284	IO::AIO::fadvise $fh, $offset, $len, $advice
		285	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		286	IO::AIO::munmap $scalar
273	IO::AIO::madvise $scalar, $offset, $length, $advice	287	IO::AIO::madvise $scalar, $offset, $length, $advice
274	IO::AIO::mprotect $scalar, $offset, $length, $protect	288	IO::AIO::mprotect $scalar, $offset, $length, $protect
275	IO::AIO::munlock $scalar, $offset = 0, $length = undef	289	IO::AIO::munlock $scalar, $offset = 0, $length = undef
276	IO::AIO::munlockall	290	IO::AIO::munlockall
277		291
278	=head2 AIO REQUEST FUNCTIONS	292	=head2 API NOTES
279		293
280	All the C<aio_*> calls are more or less thin wrappers around the syscall	294	All the C<aio_*> calls are more or less thin wrappers around the syscall
281	with the same name (sans C<aio_>). The arguments are similar or identical,	295	with the same name (sans C<aio_>). The arguments are similar or identical,
282	and they all accept an additional (and optional) C<$callback> argument	296	and they all accept an additional (and optional) C<$callback> argument
283	which must be a code reference. This code reference will get called with	297	which must be a code reference. This code reference will be called after
284	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	298	the syscall has been executed in an asynchronous fashion. The results
285	perl, which usually delivers "false") as its sole argument after the given	299	of the request will be passed as arguments to the callback (and, if an
286	syscall has been executed asynchronously.	300	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		301	most syscalls return C<-1> on error, unlike perl, which usually delivers
		302	"false").
		303
		304	Some requests (such as C<aio_readdir>) pass the actual results and
		305	communicate failures by passing C<undef>.
287		306
288	All functions expecting a filehandle keep a copy of the filehandle	307	All functions expecting a filehandle keep a copy of the filehandle
289	internally until the request has finished.	308	internally until the request has finished.
290		309
291	All functions return request objects of type L<IO::AIO::REQ> that allow	310	All functions return request objects of type L<IO::AIO::REQ> that allow
292	further manipulation of those requests while they are in-flight.	311	further manipulation of those requests while they are in-flight.
293		312
294	The pathnames you pass to these routines I<must> be absolute and	313	The pathnames you pass to these routines I<should> be absolute. The
295	encoded as octets. The reason for the former is that at the time the	314	reason for this is that at the time the request is being executed, the
296	request is being executed, the current working directory could have	315	current working directory could have changed. Alternatively, you can
297	changed. Alternatively, you can make sure that you never change the	316	make sure that you never change the current working directory anywhere
298	current working directory anywhere in the program and then use relative	317	in the program and then use relative paths. You can also take advantage
299	paths.	318	of IO::AIOs working directory abstraction, that lets you specify paths
		319	relative to some previously-opened "working directory object" - see the
		320	description of the C<IO::AIO::WD> class later in this document.
300		321
301	To encode pathnames as octets, either make sure you either: a) always pass	322	To encode pathnames as octets, either make sure you either: a) always pass
302	in filenames you got from outside (command line, readdir etc.) without	323	in filenames you got from outside (command line, readdir etc.) without
303	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	324	tinkering, b) are in your native filesystem encoding, c) use the Encode
304	your pathnames to the locale (or other) encoding in effect in the user	325	module and encode your pathnames to the locale (or other) encoding in
305	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	326	effect in the user environment, d) use Glib::filename_from_unicode on
306	use something else to ensure your scalar has the correct contents.	327	unicode filenames or e) use something else to ensure your scalar has the
		328	correct contents.
307		329
308	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	330	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
309	handles correctly whether it is set or not.	331	handles correctly whether it is set or not.
		332
		333	=head2 AIO REQUEST FUNCTIONS
310		334
311	=over 4	335	=over 4
312		336
313	=item $prev_pri = aioreq_pri [$pri]	337	=item $prev_pri = aioreq_pri [$pri]
314		338
…		…
344		368
345		369
346	=item aio_open $pathname, $flags, $mode, $callback->($fh)	370	=item aio_open $pathname, $flags, $mode, $callback->($fh)
347		371
348	Asynchronously open or create a file and call the callback with a newly	372	Asynchronously open or create a file and call the callback with a newly
349	created filehandle for the file.	373	created filehandle for the file (or C<undef> in case of an error).
350		374
351	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	375	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
352	for an explanation.	376	for an explanation.
353		377
354	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	378	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
377	following POSIX and non-POSIX constants are available (missing ones on	401	following POSIX and non-POSIX constants are available (missing ones on
378	your system are, as usual, C<0>):	402	your system are, as usual, C<0>):
379		403
380	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	404	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
381	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,	405	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
382	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.	406	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
383		407
384		408
385	=item aio_close $fh, $callback->($status)	409	=item aio_close $fh, $callback->($status)
386		410
387	Asynchronously close a file and call the callback with the result	411	Asynchronously close a file and call the callback with the result
…		…
397	Or in other words: the file descriptor will be closed, but it will not be	421	Or in other words: the file descriptor will be closed, but it will not be
398	free for reuse until the perl filehandle is closed.	422	free for reuse until the perl filehandle is closed.
399		423
400	=cut	424	=cut
401		425
		426	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		427
		428	Seeks the filehandle to the new C<$offset>, similarly to perl's
		429	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		430	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		431	C<IO::AIO::SEEK_END>).
		432
		433	The resulting absolute offset will be passed to the callback, or C<-1> in
		434	case of an error.
		435
		436	In theory, the C<$whence> constants could be different than the
		437	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		438	so don't panic.
		439
		440	As a GNU/Linux (and maybe Solaris) extension, also the constants
		441	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		442	could be found. No guarantees about suitability for use in C<aio_seek> or
		443	Perl's C<sysseek> can be made though, although I would naively assume they
		444	"just work".
		445
402	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	446	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
403		447
404	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	448	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
405		449
406	Reads or writes C<$length> bytes from or to the specified C<$fh> and	450	Reads or writes C<$length> bytes from or to the specified C<$fh> and
407	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>	451	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
408	and calls the callback without the actual number of bytes read (or -1 on	452	calls the callback with the actual number of bytes transferred (or -1 on
409	error, just like the syscall).	453	error, just like the syscall).
410		454
411	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	455	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
412	offset plus the actual number of bytes read.	456	offset plus the actual number of bytes read.
413		457
…		…
471	As native sendfile syscalls (as practically any non-POSIX interface hacked	515	As native sendfile syscalls (as practically any non-POSIX interface hacked
472	together in a hurry to improve benchmark numbers) tend to be rather buggy	516	together in a hurry to improve benchmark numbers) tend to be rather buggy
473	on many systems, this implementation tries to work around some known bugs	517	on many systems, this implementation tries to work around some known bugs
474	in Linux and FreeBSD kernels (probably others, too), but that might fail,	518	in Linux and FreeBSD kernels (probably others, too), but that might fail,
475	so you really really should check the return value of C<aio_sendfile> -	519	so you really really should check the return value of C<aio_sendfile> -
476	fewre bytes than expected might have been transferred.	520	fewer bytes than expected might have been transferred.
477		521
478		522
479	=item aio_readahead $fh,$offset,$length, $callback->($retval)	523	=item aio_readahead $fh,$offset,$length, $callback->($retval)
480		524
481	C<aio_readahead> populates the page cache with data from a file so that	525	C<aio_readahead> populates the page cache with data from a file so that
…		…
485	whole pages, so that offset is effectively rounded down to a page boundary	529	whole pages, so that offset is effectively rounded down to a page boundary
486	and bytes are read up to the next page boundary greater than or equal to	530	and bytes are read up to the next page boundary greater than or equal to
487	(off-set+length). C<aio_readahead> does not read beyond the end of the	531	(off-set+length). C<aio_readahead> does not read beyond the end of the
488	file. The current file offset of the file is left unchanged.	532	file. The current file offset of the file is left unchanged.
489		533
490	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	534	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
491	emulated by simply reading the data, which would have a similar effect.	535	be emulated by simply reading the data, which would have a similar effect.
492		536
493		537
494	=item aio_stat $fh_or_path, $callback->($status)	538	=item aio_stat $fh_or_path, $callback->($status)
495		539
496	=item aio_lstat $fh, $callback->($status)	540	=item aio_lstat $fh, $callback->($status)
…		…
565	namemax => 255,	609	namemax => 255,
566	frsize => 1024,	610	frsize => 1024,
567	fsid => 1810	611	fsid => 1810
568	}	612	}
569		613
		614	Here is a (likely partial - send me updates!) list of fsid values used by
		615	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		616
		617	0x0000adf5 adfs
		618	0x0000adff affs
		619	0x5346414f afs
		620	0x09041934 anon-inode filesystem
		621	0x00000187 autofs
		622	0x42465331 befs
		623	0x1badface bfs
		624	0x42494e4d binfmt_misc
		625	0x9123683e btrfs
		626	0x0027e0eb cgroupfs
		627	0xff534d42 cifs
		628	0x73757245 coda
		629	0x012ff7b7 coh
		630	0x28cd3d45 cramfs
		631	0x453dcd28 cramfs-wend (wrong endianness)
		632	0x64626720 debugfs
		633	0x00001373 devfs
		634	0x00001cd1 devpts
		635	0x0000f15f ecryptfs
		636	0x00414a53 efs
		637	0x0000137d ext
		638	0x0000ef53 ext2/ext3/ext4
		639	0x0000ef51 ext2
		640	0xf2f52010 f2fs
		641	0x00004006 fat
		642	0x65735546 fuseblk
		643	0x65735543 fusectl
		644	0x0bad1dea futexfs
		645	0x01161970 gfs2
		646	0x47504653 gpfs
		647	0x00004244 hfs
		648	0xf995e849 hpfs
		649	0x00c0ffee hostfs
		650	0x958458f6 hugetlbfs
		651	0x2bad1dea inotifyfs
		652	0x00009660 isofs
		653	0x000072b6 jffs2
		654	0x3153464a jfs
		655	0x6b414653 k-afs
		656	0x0bd00bd0 lustre
		657	0x0000137f minix
		658	0x0000138f minix 30 char names
		659	0x00002468 minix v2
		660	0x00002478 minix v2 30 char names
		661	0x00004d5a minix v3
		662	0x19800202 mqueue
		663	0x00004d44 msdos
		664	0x0000564c novell
		665	0x00006969 nfs
		666	0x6e667364 nfsd
		667	0x00003434 nilfs
		668	0x5346544e ntfs
		669	0x00009fa1 openprom
		670	0x7461636F ocfs2
		671	0x00009fa0 proc
		672	0x6165676c pstorefs
		673	0x0000002f qnx4
		674	0x68191122 qnx6
		675	0x858458f6 ramfs
		676	0x52654973 reiserfs
		677	0x00007275 romfs
		678	0x67596969 rpc_pipefs
		679	0x73636673 securityfs
		680	0xf97cff8c selinux
		681	0x0000517b smb
		682	0x534f434b sockfs
		683	0x73717368 squashfs
		684	0x62656572 sysfs
		685	0x012ff7b6 sysv2
		686	0x012ff7b5 sysv4
		687	0x01021994 tmpfs
		688	0x15013346 udf
		689	0x00011954 ufs
		690	0x54190100 ufs byteswapped
		691	0x00009fa2 usbdevfs
		692	0x01021997 v9fs
		693	0xa501fcf5 vxfs
		694	0xabba1974 xenfs
		695	0x012ff7b4 xenix
		696	0x58465342 xfs
		697	0x012fd16d xia
570		698
571	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	699	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
572		700
573	Works like perl's C<utime> function (including the special case of $atime	701	Works like perl's C<utime> function (including the special case of $atime
574	and $mtime being undef). Fractional times are supported if the underlying	702	and $mtime being undef). Fractional times are supported if the underlying
…		…
602	=item aio_truncate $fh_or_path, $offset, $callback->($status)	730	=item aio_truncate $fh_or_path, $offset, $callback->($status)
603		731
604	Works like truncate(2) or ftruncate(2).	732	Works like truncate(2) or ftruncate(2).
605		733
606		734
		735	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		736
		737	Allocates or frees disk space according to the C<$mode> argument. See the
		738	linux C<fallocate> documentation for details.
		739
		740	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		741	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		742	to deallocate a file range.
		743
		744	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		745	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		746	your L<fallocate(2)> manpage).
		747
		748	The file system block size used by C<fallocate> is presumably the
		749	C<f_bsize> returned by C<statvfs>.
		750
		751	If C<fallocate> isn't available or cannot be emulated (currently no
		752	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		753
		754
607	=item aio_chmod $fh_or_path, $mode, $callback->($status)	755	=item aio_chmod $fh_or_path, $mode, $callback->($status)
608		756
609	Works like perl's C<chmod> function.	757	Works like perl's C<chmod> function.
610		758
611		759
…		…
613		761
614	Asynchronously unlink (delete) a file and call the callback with the	762	Asynchronously unlink (delete) a file and call the callback with the
615	result code.	763	result code.
616		764
617		765
618	=item aio_mknod $path, $mode, $dev, $callback->($status)	766	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
619		767
620	[EXPERIMENTAL]	768	[EXPERIMENTAL]
621		769
622	Asynchronously create a device node (or fifo). See mknod(2).	770	Asynchronously create a device node (or fifo). See mknod(2).
623		771
624	The only (POSIX-) portable way of calling this function is:	772	The only (POSIX-) portable way of calling this function is:
625		773
626	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	774	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
627		775
628	See C<aio_stat> for info about some potentially helpful extra constants	776	See C<aio_stat> for info about some potentially helpful extra constants
629	and functions.	777	and functions.
630		778
631	=item aio_link $srcpath, $dstpath, $callback->($status)	779	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
638		786
639	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	787	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
640	the path C<$dstpath> and call the callback with the result code.	788	the path C<$dstpath> and call the callback with the result code.
641		789
642		790
643	=item aio_readlink $path, $callback->($link)	791	=item aio_readlink $pathname, $callback->($link)
644		792
645	Asynchronously read the symlink specified by C<$path> and pass it to	793	Asynchronously read the symlink specified by C<$path> and pass it to
646	the callback. If an error occurs, nothing or undef gets passed to the	794	the callback. If an error occurs, nothing or undef gets passed to the
647	callback.	795	callback.
648		796
649		797
650	=item aio_realpath $path, $callback->($path)	798	=item aio_realpath $pathname, $callback->($path)
651		799
652	Asynchronously make the path absolute and resolve any symlinks in	800	Asynchronously make the path absolute and resolve any symlinks in
653	C<$path>. The resulting path only consists of directories (Same as	801	C<$path>. The resulting path only consists of directories (same as
654	L<Cwd::realpath>).	802	L<Cwd::realpath>).
655		803
656	This request can be used to get the absolute path of the current working	804	This request can be used to get the absolute path of the current working
657	directory by passing it a path of F<.> (a single dot).	805	directory by passing it a path of F<.> (a single dot).
658		806
659		807
660	=item aio_rename $srcpath, $dstpath, $callback->($status)	808	=item aio_rename $srcpath, $dstpath, $callback->($status)
661		809
662	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	810	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
663	rename(2) and call the callback with the result code.	811	rename(2) and call the callback with the result code.
		812
		813	On systems that support the AIO::WD working directory abstraction
		814	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		815	of failing, C<rename> is called on the absolute path of C<$wd>.
		816
		817
		818	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		819
		820	Basically a version of C<aio_rename> with an additional C<$flags>
		821	argument. Calling this with C<$flags=0> is the same as calling
		822	C<aio_rename>.
		823
		824	Non-zero flags are currently only supported on GNU/Linux systems that
		825	support renameat2. Other systems fail with C<ENOSYS> in this case.
		826
		827	The following constants are available (missing ones are, as usual C<0>),
		828	see renameat2(2) for details:
		829
		830	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		831	and C<IO::AIO::RENAME_WHITEOUT>.
664		832
665		833
666	=item aio_mkdir $pathname, $mode, $callback->($status)	834	=item aio_mkdir $pathname, $mode, $callback->($status)
667		835
668	Asynchronously mkdir (create) a directory and call the callback with	836	Asynchronously mkdir (create) a directory and call the callback with
…		…
673	=item aio_rmdir $pathname, $callback->($status)	841	=item aio_rmdir $pathname, $callback->($status)
674		842
675	Asynchronously rmdir (delete) a directory and call the callback with the	843	Asynchronously rmdir (delete) a directory and call the callback with the
676	result code.	844	result code.
677		845
		846	On systems that support the AIO::WD working directory abstraction
		847	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		848	C<rmdir> is called on the absolute path of C<$wd>.
		849
678		850
679	=item aio_readdir $pathname, $callback->($entries)	851	=item aio_readdir $pathname, $callback->($entries)
680		852
681	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	853	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
682	directory (i.e. opendir + readdir + closedir). The entries will not be	854	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
686	array-ref with the filenames.	858	array-ref with the filenames.
687		859
688		860
689	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	861	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
690		862
691	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	863	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
692	behaviour and output format. In case of an error, C<$entries> will be	864	tune behaviour and output format. In case of an error, C<$entries> will be
693	C<undef>.	865	C<undef>.
694		866
695	The flags are a combination of the following constants, ORed together (the	867	The flags are a combination of the following constants, ORed together (the
696	flags will also be passed to the callback, possibly modified):	868	flags will also be passed to the callback, possibly modified):
697		869
…		…
744		916
745	=item IO::AIO::READDIR_FOUND_UNKNOWN	917	=item IO::AIO::READDIR_FOUND_UNKNOWN
746		918
747	This flag should not be set when calling C<aio_readdirx>. Instead, it	919	This flag should not be set when calling C<aio_readdirx>. Instead, it
748	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	920	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
749	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	921	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
750	C<$type>'s are known, which can be used to speed up some algorithms.	922	C<$type>'s are known, which can be used to speed up some algorithms.
751		923
752	=back	924	=back
753		925
754		926
755	=item aio_load $path, $data, $callback->($status)	927	=item aio_load $pathname, $data, $callback->($status)
756		928
757	This is a composite request that tries to fully load the given file into	929	This is a composite request that tries to fully load the given file into
758	memory. Status is the same as with aio_read.	930	memory. Status is the same as with aio_read.
759		931
760	=cut	932	=cut
…		…
895	};	1067	};
896		1068
897	$grp	1069	$grp
898	}	1070	}
899		1071
900	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1072	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
901		1073
902	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1074	Scans a directory (similar to C<aio_readdir>) but additionally tries to
903	efficiently separate the entries of directory C<$path> into two sets of	1075	efficiently separate the entries of directory C<$path> into two sets of
904	names, directories you can recurse into (directories), and ones you cannot	1076	names, directories you can recurse into (directories), and ones you cannot
905	recurse into (everything else, including symlinks to directories).	1077	recurse into (everything else, including symlinks to directories).
…		…
936	Then entries will be sorted into likely directories a non-initial dot	1108	Then entries will be sorted into likely directories a non-initial dot
937	currently) and likely non-directories (see C<aio_readdirx>). Then every	1109	currently) and likely non-directories (see C<aio_readdirx>). Then every
938	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1110	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
939	in order of their inode numbers. If that succeeds, it assumes that the	1111	in order of their inode numbers. If that succeeds, it assumes that the
940	entry is a directory or a symlink to directory (which will be checked	1112	entry is a directory or a symlink to directory (which will be checked
941	seperately). This is often faster than stat'ing the entry itself because	1113	separately). This is often faster than stat'ing the entry itself because
942	filesystems might detect the type of the entry without reading the inode	1114	filesystems might detect the type of the entry without reading the inode
943	data (e.g. ext2fs filetype feature), even on systems that cannot return	1115	data (e.g. ext2fs filetype feature), even on systems that cannot return
944	the filetype information on readdir.	1116	the filetype information on readdir.
945		1117
946	If the known number of directories (link count - 2) has been reached, the	1118	If the known number of directories (link count - 2) has been reached, the
…		…
962		1134
963	my $grp = aio_group $cb;	1135	my $grp = aio_group $cb;
964		1136
965	$maxreq = 4 if $maxreq <= 0;	1137	$maxreq = 4 if $maxreq <= 0;
966		1138
967	# stat once	1139	# get a wd object
968	aioreq_pri $pri;	1140	aioreq_pri $pri;
969	add $grp aio_stat $path, sub {	1141	add $grp aio_wd $path, sub {
		1142	$_[0]
970	return $grp->result () if $_[0];	1143	or return $grp->result ();
971	my $now = time;
972	my $hash1 = join ":", (stat _)[0,1,3,7,9];
973		1144
974	# read the directory entries	1145	my $wd = [shift, "."];
		1146
		1147	# stat once
975	aioreq_pri $pri;	1148	aioreq_pri $pri;
976	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1149	add $grp aio_stat $wd, sub {
977	my $entries = shift
978	or return $grp->result ();	1150	return $grp->result () if $_[0];
		1151	my $now = time;
		1152	my $hash1 = join ":", (stat _)[0,1,3,7,9];
979		1153
980	# stat the dir another time	1154	# read the directory entries
981	aioreq_pri $pri;	1155	aioreq_pri $pri;
		1156	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1157	my $entries = shift
		1158	or return $grp->result ();
		1159
		1160	# stat the dir another time
		1161	aioreq_pri $pri;
982	add $grp aio_stat $path, sub {	1162	add $grp aio_stat $wd, sub {
983	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1163	my $hash2 = join ":", (stat _)[0,1,3,7,9];
984		1164
985	my $ndirs;	1165	my $ndirs;
986		1166
987	# take the slow route if anything looks fishy	1167	# take the slow route if anything looks fishy
988	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1168	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
989	$ndirs = -1;	1169	$ndirs = -1;
990	} else {	1170	} else {
991	# if nlink == 2, we are finished	1171	# if nlink == 2, we are finished
992	# for non-posix-fs's, we rely on nlink < 2	1172	# for non-posix-fs's, we rely on nlink < 2
993	$ndirs = (stat _)[3] - 2	1173	$ndirs = (stat _)[3] - 2
994	or return $grp->result ([], $entries);	1174	or return $grp->result ([], $entries);
995	}	1175	}
996		1176
997	my (@dirs, @nondirs);	1177	my (@dirs, @nondirs);
998		1178
999	my $statgrp = add $grp aio_group sub {	1179	my $statgrp = add $grp aio_group sub {
1000	$grp->result (\@dirs, \@nondirs);	1180	$grp->result (\@dirs, \@nondirs);
1001	};	1181	};
1002		1182
1003	limit $statgrp $maxreq;	1183	limit $statgrp $maxreq;
1004	feed $statgrp sub {	1184	feed $statgrp sub {
1005	return unless @$entries;	1185	return unless @$entries;
1006	my $entry = shift @$entries;	1186	my $entry = shift @$entries;
1007		1187
1008	aioreq_pri $pri;	1188	aioreq_pri $pri;
		1189	$wd->[1] = "$entry/.";
1009	add $statgrp aio_stat "$path/$entry/.", sub {	1190	add $statgrp aio_stat $wd, sub {
1010	if ($_[0] < 0) {	1191	if ($_[0] < 0) {
1011	push @nondirs, $entry;	1192	push @nondirs, $entry;
1012	} else {	1193	} else {
1013	# need to check for real directory	1194	# need to check for real directory
1014	aioreq_pri $pri;	1195	aioreq_pri $pri;
		1196	$wd->[1] = $entry;
1015	add $statgrp aio_lstat "$path/$entry", sub {	1197	add $statgrp aio_lstat $wd, sub {
1016	if (-d _) {	1198	if (-d _) {
1017	push @dirs, $entry;	1199	push @dirs, $entry;
1018		1200
1019	unless (--$ndirs) {	1201	unless (--$ndirs) {
1020	push @nondirs, @$entries;	1202	push @nondirs, @$entries;
1021	feed $statgrp;	1203	feed $statgrp;
		1204	}
		1205	} else {
		1206	push @nondirs, $entry;
1022	}	1207	}
1023	} else {
1024	push @nondirs, $entry;
1025	}	1208	}
1026	}	1209	}
1027	}	1210	};
1028	};	1211	};
1029	};	1212	};
1030	};	1213	};
1031	};	1214	};
1032	};	1215	};
1033		1216
1034	$grp	1217	$grp
1035	}	1218	}
1036		1219
1037	=item aio_rmtree $path, $callback->($status)	1220	=item aio_rmtree $pathname, $callback->($status)
1038		1221
1039	Delete a directory tree starting (and including) C<$path>, return the	1222	Delete a directory tree starting (and including) C<$path>, return the
1040	status of the final C<rmdir> only. This is a composite request that	1223	status of the final C<rmdir> only. This is a composite request that
1041	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1224	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1042	everything else.	1225	everything else.
1043		1226
1044	=cut	1227	=cut
1045		1228
…		…
1067	};	1250	};
1068		1251
1069	$grp	1252	$grp
1070	}	1253	}
1071		1254
		1255	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1256
		1257	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1258
		1259	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1260	they execute asynchronously and pass the return value to the callback.
		1261
		1262	Both calls can be used for a lot of things, some of which make more sense
		1263	to run asynchronously in their own thread, while some others make less
		1264	sense. For example, calls that block waiting for external events, such
		1265	as locking, will also lock down an I/O thread while it is waiting, which
		1266	can deadlock the whole I/O system. At the same time, there might be no
		1267	alternative to using a thread to wait.
		1268
		1269	So in general, you should only use these calls for things that do
		1270	(filesystem) I/O, not for things that wait for other events (network,
		1271	other processes), although if you are careful and know what you are doing,
		1272	you still can.
		1273
		1274	The following constants are available (missing ones are, as usual C<0>):
		1275
		1276	C<F_DUPFD_CLOEXEC>,
		1277
		1278	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1279
		1280	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1281
		1282	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1283	C<FS_IOC_FIEMAP>.
		1284
		1285	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1286	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1287
		1288	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1289	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1290	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1291	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1292	C<FS_FL_USER_MODIFIABLE>.
		1293
		1294	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1295	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1296	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1297	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
		1298
1072	=item aio_sync $callback->($status)	1299	=item aio_sync $callback->($status)
1073		1300
1074	Asynchronously call sync and call the callback when finished.	1301	Asynchronously call sync and call the callback when finished.
1075		1302
1076	=item aio_fsync $fh, $callback->($status)	1303	=item aio_fsync $fh, $callback->($status)
…		…
1083	Asynchronously call fdatasync on the given filehandle and call the	1310	Asynchronously call fdatasync on the given filehandle and call the
1084	callback with the fdatasync result code.	1311	callback with the fdatasync result code.
1085		1312
1086	If this call isn't available because your OS lacks it or it couldn't be	1313	If this call isn't available because your OS lacks it or it couldn't be
1087	detected, it will be emulated by calling C<fsync> instead.	1314	detected, it will be emulated by calling C<fsync> instead.
		1315
		1316	=item aio_syncfs $fh, $callback->($status)
		1317
		1318	Asynchronously call the syncfs syscall to sync the filesystem associated
		1319	to the given filehandle and call the callback with the syncfs result
		1320	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1321	errno to C<ENOSYS> nevertheless.
1088		1322
1089	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1323	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1090		1324
1091	Sync the data portion of the file specified by C<$offset> and C<$length>	1325	Sync the data portion of the file specified by C<$offset> and C<$length>
1092	to disk (but NOT the metadata), by calling the Linux-specific	1326	to disk (but NOT the metadata), by calling the Linux-specific
…		…
1096	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1330	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1097	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1331	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1098	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1332	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1099	manpage for details.	1333	manpage for details.
1100		1334
1101	=item aio_pathsync $path, $callback->($status)	1335	=item aio_pathsync $pathname, $callback->($status)
1102		1336
1103	This request tries to open, fsync and close the given path. This is a	1337	This request tries to open, fsync and close the given path. This is a
1104	composite request intended to sync directories after directory operations	1338	composite request intended to sync directories after directory operations
1105	(E.g. rename). This might not work on all operating systems or have any	1339	(E.g. rename). This might not work on all operating systems or have any
1106	specific effect, but usually it makes sure that directory changes get	1340	specific effect, but usually it makes sure that directory changes get
…		…
1137	};	1371	};
1138		1372
1139	$grp	1373	$grp
1140	}	1374	}
1141		1375
1142	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1376	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1143		1377
1144	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1378	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1145	scalars (see the C<IO::AIO::mmap> function, although it also works on data	1379	scalars (see the C<IO::AIO::mmap> function, although it also works on data
1146	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the	1380	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1147	scalar must only be modified in-place while an aio operation is pending on	1381	scalar must only be modified in-place while an aio operation is pending on
…		…
1149		1383
1150	It calls the C<msync> function of your OS, if available, with the memory	1384	It calls the C<msync> function of your OS, if available, with the memory
1151	area starting at C<$offset> in the string and ending C<$length> bytes	1385	area starting at C<$offset> in the string and ending C<$length> bytes
1152	later. If C<$length> is negative, counts from the end, and if C<$length>	1386	later. If C<$length> is negative, counts from the end, and if C<$length>
1153	is C<undef>, then it goes till the end of the string. The flags can be	1387	is C<undef>, then it goes till the end of the string. The flags can be
1154	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and	1388	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1155	C<IO::AIO::MS_SYNC>.	1389	C<IO::AIO::MS_INVALIDATE>.
1156		1390
1157	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1391	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1158		1392
1159	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1393	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1160	scalars.	1394	scalars.
1161		1395
1162	It touches (reads or writes) all memory pages in the specified	1396	It touches (reads or writes) all memory pages in the specified
1163	range inside the scalar. All caveats and parameters are the same	1397	range inside the scalar. All caveats and parameters are the same
1164	as for C<aio_msync>, above, except for flags, which must be either	1398	as for C<aio_msync>, above, except for flags, which must be either
1165	C<0> (which reads all pages and ensures they are instantiated) or	1399	C<0> (which reads all pages and ensures they are instantiated) or
1166	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1400	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1167	writing an octet from it, which dirties the page).	1401	writing an octet from it, which dirties the page).
1168		1402
1169	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1403	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1170		1404
1171	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1405	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1202	documented under L<MISCELLANEOUS FUNCTIONS>.	1436	documented under L<MISCELLANEOUS FUNCTIONS>.
1203		1437
1204	Example: asynchronously lock all current and future pages into memory.	1438	Example: asynchronously lock all current and future pages into memory.
1205		1439
1206	aio_mlockall IO::AIO::MCL_FUTURE;	1440	aio_mlockall IO::AIO::MCL_FUTURE;
		1441
		1442	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1443
		1444	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1445	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1446	the ioctl is not available on your OS, then this request will fail with
		1447	C<ENOSYS>.
		1448
		1449	C<$start> is the starting offset to query extents for, C<$length> is the
		1450	size of the range to query - if it is C<undef>, then the whole file will
		1451	be queried.
		1452
		1453	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1454	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1455	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1456	the data portion.
		1457
		1458	C<$count> is the maximum number of extent records to return. If it is
		1459	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1460	case, if it is C<0>, then the callback receives the number of extents
		1461	instead of the extents themselves (which is unreliable, see below).
		1462
		1463	If an error occurs, the callback receives no arguments. The special
		1464	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1465
		1466	Otherwise, the callback receives an array reference with extent
		1467	structures. Each extent structure is an array reference itself, with the
		1468	following members:
		1469
		1470	[$logical, $physical, $length, $flags]
		1471
		1472	Flags is any combination of the following flag values (typically either C<0>
		1473	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1474
		1475	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1476	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1477	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1478	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1479	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1480	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1481
		1482	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1483	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1484	it to return all extents of a range for files with large number of
		1485	extents. The code works around all these issues if C<$count> is undef.
1207		1486
1208	=item aio_group $callback->(...)	1487	=item aio_group $callback->(...)
1209		1488
1210	This is a very special aio request: Instead of doing something, it is a	1489	This is a very special aio request: Instead of doing something, it is a
1211	container for other aio requests, which is useful if you want to bundle	1490	container for other aio requests, which is useful if you want to bundle
…		…
1248	like sleep and file handle readable/writable, the overhead this creates is	1527	like sleep and file handle readable/writable, the overhead this creates is
1249	immense (it blocks a thread for a long time) so do not use this function	1528	immense (it blocks a thread for a long time) so do not use this function
1250	except to put your application under artificial I/O pressure.	1529	except to put your application under artificial I/O pressure.
1251		1530
1252	=back	1531	=back
		1532
		1533
		1534	=head2 IO::AIO::WD - multiple working directories
		1535
		1536	Your process only has one current working directory, which is used by all
		1537	threads. This makes it hard to use relative paths (some other component
		1538	could call C<chdir> at any time, and it is hard to control when the path
		1539	will be used by IO::AIO).
		1540
		1541	One solution for this is to always use absolute paths. This usually works,
		1542	but can be quite slow (the kernel has to walk the whole path on every
		1543	access), and can also be a hassle to implement.
		1544
		1545	Newer POSIX systems have a number of functions (openat, fdopendir,
		1546	futimensat and so on) that make it possible to specify working directories
		1547	per operation.
		1548
		1549	For portability, and because the clowns who "designed", or shall I write,
		1550	perpetrated this new interface were obviously half-drunk, this abstraction
		1551	cannot be perfect, though.
		1552
		1553	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1554	object. This object stores the canonicalised, absolute version of the
		1555	path, and on systems that allow it, also a directory file descriptor.
		1556
		1557	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1558	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1559	object and a pathname instead (or the IO::AIO::WD object alone, which
		1560	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1561	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1562	to that IO::AIO::WD object.
		1563
		1564	For example, to get a wd object for F</etc> and then stat F<passwd>
		1565	inside, you would write:
		1566
		1567	aio_wd "/etc", sub {
		1568	my $etcdir = shift;
		1569
		1570	# although $etcdir can be undef on error, there is generally no reason
		1571	# to check for errors here, as aio_stat will fail with ENOENT
		1572	# when $etcdir is undef.
		1573
		1574	aio_stat [$etcdir, "passwd"], sub {
		1575	# yay
		1576	};
		1577	};
		1578
		1579	The fact that C<aio_wd> is a request and not a normal function shows that
		1580	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1581	which is why it is done asynchronously.
		1582
		1583	To stat the directory obtained with C<aio_wd> above, one could write
		1584	either of the following three request calls:
		1585
		1586	aio_lstat "/etc" , sub { ... # pathname as normal string
		1587	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1588	aio_lstat $wd , sub { ... # shorthand for the previous
		1589
		1590	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1591	object and the pathname string, so you could write the following without
		1592	causing any issues due to C<$path> getting reused:
		1593
		1594	my $path = [$wd, undef];
		1595
		1596	for my $name (qw(abc def ghi)) {
		1597	$path->[1] = $name;
		1598	aio_stat $path, sub {
		1599	# ...
		1600	};
		1601	}
		1602
		1603	There are some caveats: when directories get renamed (or deleted), the
		1604	pathname string doesn't change, so will point to the new directory (or
		1605	nowhere at all), while the directory fd, if available on the system,
		1606	will still point to the original directory. Most functions accepting a
		1607	pathname will use the directory fd on newer systems, and the string on
		1608	older systems. Some functions (such as realpath) will always rely on the
		1609	string form of the pathname.
		1610
		1611	So this functionality is mainly useful to get some protection against
		1612	C<chdir>, to easily get an absolute path out of a relative path for future
		1613	reference, and to speed up doing many operations in the same directory
		1614	(e.g. when stat'ing all files in a directory).
		1615
		1616	The following functions implement this working directory abstraction:
		1617
		1618	=over 4
		1619
		1620	=item aio_wd $pathname, $callback->($wd)
		1621
		1622	Asynchonously canonicalise the given pathname and convert it to an
		1623	IO::AIO::WD object representing it. If possible and supported on the
		1624	system, also open a directory fd to speed up pathname resolution relative
		1625	to this working directory.
		1626
		1627	If something goes wrong, then C<undef> is passwd to the callback instead
		1628	of a working directory object and C<$!> is set appropriately. Since
		1629	passing C<undef> as working directory component of a pathname fails the
		1630	request with C<ENOENT>, there is often no need for error checking in the
		1631	C<aio_wd> callback, as future requests using the value will fail in the
		1632	expected way.
		1633
		1634	=item IO::AIO::CWD
		1635
		1636	This is a compiletime constant (object) that represents the process
		1637	current working directory.
		1638
		1639	Specifying this object as working directory object for a pathname is as if
		1640	the pathname would be specified directly, without a directory object. For
		1641	example, these calls are functionally identical:
		1642
		1643	aio_stat "somefile", sub { ... };
		1644	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1645
		1646	=back
		1647
		1648	To recover the path associated with an IO::AIO::WD object, you can use
		1649	C<aio_realpath>:
		1650
		1651	aio_realpath $wd, sub {
		1652	warn "path is $_[0]\n";
		1653	};
		1654
		1655	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1656	sometimes, fall back to using an absolue path.
1253		1657
1254	=head2 IO::AIO::REQ CLASS	1658	=head2 IO::AIO::REQ CLASS
1255		1659
1256	All non-aggregate C<aio_*> functions return an object of this class when	1660	All non-aggregate C<aio_*> functions return an object of this class when
1257	called in non-void context.	1661	called in non-void context.
…		…
1375		1779
1376	Sets a feeder/generator on this group: every group can have an attached	1780	Sets a feeder/generator on this group: every group can have an attached
1377	generator that generates requests if idle. The idea behind this is that,	1781	generator that generates requests if idle. The idea behind this is that,
1378	although you could just queue as many requests as you want in a group,	1782	although you could just queue as many requests as you want in a group,
1379	this might starve other requests for a potentially long time. For example,	1783	this might starve other requests for a potentially long time. For example,
1380	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1784	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1381	delaying any later requests for a long time.	1785	requests, delaying any later requests for a long time.
1382		1786
1383	To avoid this, and allow incremental generation of requests, you can	1787	To avoid this, and allow incremental generation of requests, you can
1384	instead a group and set a feeder on it that generates those requests. The	1788	instead a group and set a feeder on it that generates those requests. The
1385	feed callback will be called whenever there are few enough (see C<limit>,	1789	feed callback will be called whenever there are few enough (see C<limit>,
1386	below) requests active in the group itself and is expected to queue more	1790	below) requests active in the group itself and is expected to queue more
…		…
1435		1839
1436	See C<poll_cb> for an example.	1840	See C<poll_cb> for an example.
1437		1841
1438	=item IO::AIO::poll_cb	1842	=item IO::AIO::poll_cb
1439		1843
1440	Process some outstanding events on the result pipe. You have to call	1844	Process some requests that have reached the result phase (i.e. they have
		1845	been executed but the results are not yet reported). You have to call
		1846	this "regularly" to finish outstanding requests.
		1847
1441	this regularly. Returns C<0> if all events could be processed (or there	1848	Returns C<0> if all events could be processed (or there were no
1442	were no events to process), or C<-1> if it returned earlier for whatever	1849	events to process), or C<-1> if it returned earlier for whatever
1443	reason. Returns immediately when no events are outstanding. The amount of	1850	reason. Returns immediately when no events are outstanding. The amount
1444	events processed depends on the settings of C<IO::AIO::max_poll_req> and	1851	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1445	C<IO::AIO::max_poll_time>.	1852	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1446		1853
1447	If not all requests were processed for whatever reason, the filehandle	1854	If not all requests were processed for whatever reason, the poll file
1448	will still be ready when C<poll_cb> returns, so normally you don't have to	1855	descriptor will still be ready when C<poll_cb> returns, so normally you
1449	do anything special to have it called later.	1856	don't have to do anything special to have it called later.
1450		1857
1451	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1858	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1452	ready, it can be beneficial to call this function from loops which submit	1859	ready, it can be beneficial to call this function from loops which submit
1453	a lot of requests, to make sure the results get processed when they become	1860	a lot of requests, to make sure the results get processed when they become
1454	available and not just when the loop is finished and the event loop takes	1861	available and not just when the loop is finished and the event loop takes
…		…
1463	poll => 'r', async => 1,	1870	poll => 'r', async => 1,
1464	cb => \&IO::AIO::poll_cb);	1871	cb => \&IO::AIO::poll_cb);
1465		1872
1466	=item IO::AIO::poll_wait	1873	=item IO::AIO::poll_wait
1467		1874
1468	If there are any outstanding requests and none of them in the result	1875	Wait until either at least one request is in the result phase or no
1469	phase, wait till the result filehandle becomes ready for reading (simply	1876	requests are outstanding anymore.
1470	does a C<select> on the filehandle. This is useful if you want to	1877
1471	synchronously wait for some requests to finish).	1878	This is useful if you want to synchronously wait for some requests to
		1879	become ready, without actually handling them.
1472		1880
1473	See C<nreqs> for an example.	1881	See C<nreqs> for an example.
1474		1882
1475	=item IO::AIO::poll	1883	=item IO::AIO::poll
1476		1884
…		…
1597		2005
1598	This is a very bad function to use in interactive programs because it	2006	This is a very bad function to use in interactive programs because it
1599	blocks, and a bad way to reduce concurrency because it is inexact: Better	2007	blocks, and a bad way to reduce concurrency because it is inexact: Better
1600	use an C<aio_group> together with a feed callback.	2008	use an C<aio_group> together with a feed callback.
1601		2009
1602	It's main use is in scripts without an event loop - when you want to stat	2010	Its main use is in scripts without an event loop - when you want to stat
1603	a lot of files, you can write somehting like this:	2011	a lot of files, you can write somehting like this:
1604		2012
1605	IO::AIO::max_outstanding 32;	2013	IO::AIO::max_outstanding 32;
1606		2014
1607	for my $path (...) {	2015	for my $path (...) {
…		…
1647		2055
1648	=back	2056	=back
1649		2057
1650	=head3 MISCELLANEOUS FUNCTIONS	2058	=head3 MISCELLANEOUS FUNCTIONS
1651		2059
1652	IO::AIO implements some functions that might be useful, but are not	2060	IO::AIO implements some functions that are useful when you want to use
1653	asynchronous.	2061	some "Advanced I/O" function not available to in Perl, without going the
		2062	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2063	counterpart.
1654		2064
1655	=over 4	2065	=over 4
1656		2066
1657	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2067	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1658		2068
…		…
1665		2075
1666	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2076	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1667		2077
1668	Simply calls the C<posix_fadvise> function (see its	2078	Simply calls the C<posix_fadvise> function (see its
1669	manpage for details). The following advice constants are	2079	manpage for details). The following advice constants are
1670	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2080	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1671	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2081	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1672	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2082	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1673		2083
1674	On systems that do not implement C<posix_fadvise>, this function returns	2084	On systems that do not implement C<posix_fadvise>, this function returns
1675	ENOSYS, otherwise the return value of C<posix_fadvise>.	2085	ENOSYS, otherwise the return value of C<posix_fadvise>.
1676		2086
1677	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2087	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1678		2088
1679	Simply calls the C<posix_madvise> function (see its	2089	Simply calls the C<posix_madvise> function (see its
1680	manpage for details). The following advice constants are	2090	manpage for details). The following advice constants are
1681	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2091	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1682	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2092	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>,
		2093	C<IO::AIO::MADV_FREE>.
		2094
		2095	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2096	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2097	will be reduced to fit into the C<$scalar>.
1683		2098
1684	On systems that do not implement C<posix_madvise>, this function returns	2099	On systems that do not implement C<posix_madvise>, this function returns
1685	ENOSYS, otherwise the return value of C<posix_madvise>.	2100	ENOSYS, otherwise the return value of C<posix_madvise>.
1686		2101
1687	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2102	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1688		2103
1689	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2104	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1690	$scalar (see its manpage for details). The following protect	2105	$scalar (see its manpage for details). The following protect
1691	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2106	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1692	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2107	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		2108
		2109	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2110	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2111	will be reduced to fit into the C<$scalar>.
1693		2112
1694	On systems that do not implement C<mprotect>, this function returns	2113	On systems that do not implement C<mprotect>, this function returns
1695	ENOSYS, otherwise the return value of C<mprotect>.	2114	ENOSYS, otherwise the return value of C<mprotect>.
1696		2115
1697	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2116	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1698		2117
1699	Memory-maps a file (or anonymous memory range) and attaches it to the	2118	Memory-maps a file (or anonymous memory range) and attaches it to the
1700	given C<$scalar>, which will act like a string scalar.	2119	given C<$scalar>, which will act like a string scalar. Returns true on
		2120	success, and false otherwise.
1701		2121
		2122	The scalar must exist, but its contents do not matter - this means you
		2123	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2124	the scalar first.
		2125
1702	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2126	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1703	change the string length, and most read-only operations such as copying it	2127	which don't change the string length, and most read-only operations such
1704	or searching it with regexes and so on.	2128	as copying it or searching it with regexes and so on.
1705		2129
1706	Anything else is unsafe and will, at best, result in memory leaks.	2130	Anything else is unsafe and will, at best, result in memory leaks.
1707		2131
1708	The memory map associated with the C<$scalar> is automatically removed	2132	The memory map associated with the C<$scalar> is automatically removed
1709	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or	2133	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1710	C<IO::AIO::munmap> functions are called.	2134	or C<IO::AIO::munmap> functions are called on it.
1711		2135
1712	This calls the C<mmap>(2) function internally. See your system's manual	2136	This calls the C<mmap>(2) function internally. See your system's manual
1713	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2137	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1714		2138
1715	The C<$length> must be larger than zero and smaller than the actual	2139	The C<$length> must be larger than zero and smaller than the actual
1716	filesize.	2140	filesize.
1717		2141
1718	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2142	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1719	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2143	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1720		2144
1721	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2145	C<$flags> can be a combination of
1722	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2146	C<IO::AIO::MAP_SHARED> or
1723	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2147	C<IO::AIO::MAP_PRIVATE>,
		2148	or a number of system-specific flags (when not available, the are C<0>):
1724	(which is set to C<MAP_ANON> if your system only provides this	2149	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1725	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2150	C<IO::AIO::MAP_LOCKED>,
1726	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2151	C<IO::AIO::MAP_NORESERVE>,
		2152	C<IO::AIO::MAP_POPULATE>,
1727	C<IO::AIO::MAP_NONBLOCK>	2153	C<IO::AIO::MAP_NONBLOCK>,
		2154	C<IO::AIO::MAP_FIXED>,
		2155	C<IO::AIO::MAP_GROWSDOWN>,
		2156	C<IO::AIO::MAP_32BIT>,
		2157	C<IO::AIO::MAP_HUGETLB> or
		2158	C<IO::AIO::MAP_STACK>.
1728		2159
1729	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2160	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1730		2161
1731	C<$offset> is the offset from the start of the file - it generally must be	2162	C<$offset> is the offset from the start of the file - it generally must be
1732	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2163	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1757		2188
1758	Calls the C<munlockall> function.	2189	Calls the C<munlockall> function.
1759		2190
1760	On systems that do not implement C<munlockall>, this function returns	2191	On systems that do not implement C<munlockall>, this function returns
1761	ENOSYS, otherwise the return value of C<munlockall>.	2192	ENOSYS, otherwise the return value of C<munlockall>.
		2193
		2194	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2195
		2196	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2197	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2198	should be the file offset.
		2199
		2200	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2201	silently corrupt the data in this case.
		2202
		2203	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2204	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2205	C<IO::AIO::SPLICE_F_GIFT>.
		2206
		2207	See the C<splice(2)> manpage for details.
		2208
		2209	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2210
		2211	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2212	description for C<IO::AIO::splice> above for details.
		2213
		2214	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2215
		2216	Attempts to query or change the pipe buffer size. Obviously works only
		2217	on pipes, and currently works only on GNU/Linux systems, and fails with
		2218	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2219	size on other systems, drop me a note.
		2220
		2221	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2222
		2223	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2224	C<$flags> is missing or C<0>, then this should be the same as a call to
		2225	perl's built-in C<pipe> function and create a new pipe, and works on
		2226	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2227	(..., 4096, O_BINARY)>.
		2228
		2229	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2230	the given flags (Linux 2.6.27, glibc 2.9).
		2231
		2232	On success, the read and write file handles are returned.
		2233
		2234	On error, nothing will be returned. If the pipe2 syscall is missing and
		2235	C<$flags> is non-zero, fails with C<ENOSYS>.
		2236
		2237	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2238	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2239	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1762		2240
1763	=back	2241	=back
1764		2242
1765	=cut	2243	=cut
1766		2244
…		…
1804	=head2 FORK BEHAVIOUR	2282	=head2 FORK BEHAVIOUR
1805		2283
1806	Usage of pthreads in a program changes the semantics of fork	2284	Usage of pthreads in a program changes the semantics of fork
1807	considerably. Specifically, only async-safe functions can be called after	2285	considerably. Specifically, only async-safe functions can be called after
1808	fork. Perl doesn't know about this, so in general, you cannot call fork	2286	fork. Perl doesn't know about this, so in general, you cannot call fork
1809	with defined behaviour in perl. IO::AIO uses pthreads, so this applies,	2287	with defined behaviour in perl if pthreads are involved. IO::AIO uses
1810	but many other extensions and (for inexplicable reasons) perl itself often	2288	pthreads, so this applies, but many other extensions and (for inexplicable
1811	is linked against pthreads, so this limitation applies.	2289	reasons) perl itself often is linked against pthreads, so this limitation
		2290	applies to quite a lot of perls.
1812		2291
1813	Some operating systems have extensions that allow safe use of fork, and	2292	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1814	this module should do "the right thing" on those, and tries on others. At	2293	only works in the process that loaded it. Forking is fully supported, but
1815	the time of this writing (2011) only GNU/Linux supports these extensions	2294	using IO::AIO in the child is not.
1816	to POSIX.	2295
		2296	You might get around by not I<using> IO::AIO before (or after)
		2297	forking. You could also try to call the L<IO::AIO::reinit> function in the
		2298	child:
		2299
		2300	=over 4
		2301
		2302	=item IO::AIO::reinit
		2303
		2304	Abandons all current requests and I/O threads and simply reinitialises all
		2305	data structures. This is not an operation supported by any standards, but
		2306	happens to work on GNU/Linux and some newer BSD systems.
		2307
		2308	The only reasonable use for this function is to call it after forking, if
		2309	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2310	the process will result in undefined behaviour. Calling it at any time
		2311	will also result in any undefined (by POSIX) behaviour.
		2312
		2313	=back
1817		2314
1818	=head2 MEMORY USAGE	2315	=head2 MEMORY USAGE
1819		2316
1820	Per-request usage:	2317	Per-request usage:
1821		2318

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing IO-AIO/AIO.pm (file contents): Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs. Revision 1.271 by root, Fri Jun 23 21:43:51 2017 UTC

Diff Legend

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs.
Revision 1.271 by root, Fri Jun 23 21:43:51 2017 UTC