[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 1.276 by root, Fri Sep 22 05:24:41 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->()
…		…
265	IO::AIO::idle_timeout $seconds	277	IO::AIO::idle_timeout $seconds
266	IO::AIO::max_outstanding $maxreqs	278	IO::AIO::max_outstanding $maxreqs
267	IO::AIO::nreqs	279	IO::AIO::nreqs
268	IO::AIO::nready	280	IO::AIO::nready
269	IO::AIO::npending	281	IO::AIO::npending
		282	IO::AIO::min_fdlimit $nfd;
270		283
271	IO::AIO::sendfile $ofh, $ifh, $offset, $count	284	IO::AIO::sendfile $ofh, $ifh, $offset, $count
272	IO::AIO::fadvise $fh, $offset, $len, $advice	285	IO::AIO::fadvise $fh, $offset, $len, $advice
		286	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		287	IO::AIO::munmap $scalar
273	IO::AIO::madvise $scalar, $offset, $length, $advice	288	IO::AIO::madvise $scalar, $offset, $length, $advice
274	IO::AIO::mprotect $scalar, $offset, $length, $protect	289	IO::AIO::mprotect $scalar, $offset, $length, $protect
275	IO::AIO::munlock $scalar, $offset = 0, $length = undef	290	IO::AIO::munlock $scalar, $offset = 0, $length = undef
276	IO::AIO::munlockall	291	IO::AIO::munlockall
277		292
278	=head2 AIO REQUEST FUNCTIONS	293	=head2 API NOTES
279		294
280	All the C<aio_*> calls are more or less thin wrappers around the syscall	295	All the C<aio_*> calls are more or less thin wrappers around the syscall
281	with the same name (sans C<aio_>). The arguments are similar or identical,	296	with the same name (sans C<aio_>). The arguments are similar or identical,
282	and they all accept an additional (and optional) C<$callback> argument	297	and they all accept an additional (and optional) C<$callback> argument
283	which must be a code reference. This code reference will get called with	298	which must be a code reference. This code reference will be called after
284	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	299	the syscall has been executed in an asynchronous fashion. The results
285	perl, which usually delivers "false") as its sole argument after the given	300	of the request will be passed as arguments to the callback (and, if an
286	syscall has been executed asynchronously.	301	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		302	most syscalls return C<-1> on error, unlike perl, which usually delivers
		303	"false").
		304
		305	Some requests (such as C<aio_readdir>) pass the actual results and
		306	communicate failures by passing C<undef>.
287		307
288	All functions expecting a filehandle keep a copy of the filehandle	308	All functions expecting a filehandle keep a copy of the filehandle
289	internally until the request has finished.	309	internally until the request has finished.
290		310
291	All functions return request objects of type L<IO::AIO::REQ> that allow	311	All functions return request objects of type L<IO::AIO::REQ> that allow
292	further manipulation of those requests while they are in-flight.	312	further manipulation of those requests while they are in-flight.
293		313
294	The pathnames you pass to these routines I<must> be absolute and	314	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	315	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	316	current working directory could have changed. Alternatively, you can
297	changed. Alternatively, you can make sure that you never change the	317	make sure that you never change the current working directory anywhere
298	current working directory anywhere in the program and then use relative	318	in the program and then use relative paths. You can also take advantage
299	paths.	319	of IO::AIOs working directory abstraction, that lets you specify paths
		320	relative to some previously-opened "working directory object" - see the
		321	description of the C<IO::AIO::WD> class later in this document.
300		322
301	To encode pathnames as octets, either make sure you either: a) always pass	323	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	324	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	325	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	326	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)	327	effect in the user environment, d) use Glib::filename_from_unicode on
306	use something else to ensure your scalar has the correct contents.	328	unicode filenames or e) use something else to ensure your scalar has the
		329	correct contents.
307		330
308	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	331	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
309	handles correctly whether it is set or not.	332	handles correctly whether it is set or not.
		333
		334	=head2 AIO REQUEST FUNCTIONS
310		335
311	=over 4	336	=over 4
312		337
313	=item $prev_pri = aioreq_pri [$pri]	338	=item $prev_pri = aioreq_pri [$pri]
314		339
…		…
344		369
345		370
346	=item aio_open $pathname, $flags, $mode, $callback->($fh)	371	=item aio_open $pathname, $flags, $mode, $callback->($fh)
347		372
348	Asynchronously open or create a file and call the callback with a newly	373	Asynchronously open or create a file and call the callback with a newly
349	created filehandle for the file.	374	created filehandle for the file (or C<undef> in case of an error).
350		375
351	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	376	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
352	for an explanation.	377	for an explanation.
353		378
354	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	379	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
377	following POSIX and non-POSIX constants are available (missing ones on	402	following POSIX and non-POSIX constants are available (missing ones on
378	your system are, as usual, C<0>):	403	your system are, as usual, C<0>):
379		404
380	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,	405	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>,	406	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>.	407	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
383		408
384		409
385	=item aio_close $fh, $callback->($status)	410	=item aio_close $fh, $callback->($status)
386		411
387	Asynchronously close a file and call the callback with the result	412	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	422	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.	423	free for reuse until the perl filehandle is closed.
399		424
400	=cut	425	=cut
401		426
		427	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		428
		429	Seeks the filehandle to the new C<$offset>, similarly to perl's
		430	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		431	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		432	C<IO::AIO::SEEK_END>).
		433
		434	The resulting absolute offset will be passed to the callback, or C<-1> in
		435	case of an error.
		436
		437	In theory, the C<$whence> constants could be different than the
		438	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		439	so don't panic.
		440
		441	As a GNU/Linux (and maybe Solaris) extension, also the constants
		442	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		443	could be found. No guarantees about suitability for use in C<aio_seek> or
		444	Perl's C<sysseek> can be made though, although I would naively assume they
		445	"just work".
		446
402	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	447	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
403		448
404	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	449	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
405		450
406	Reads or writes C<$length> bytes from or to the specified C<$fh> and	451	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<$dataoffset>	452	C<$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	453	calls the callback with the actual number of bytes transferred (or -1 on
409	error, just like the syscall).	454	error, just like the syscall).
410		455
411	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to	456	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
412	offset plus the actual number of bytes read.	457	offset plus the actual number of bytes read.
413		458
…		…
471	As native sendfile syscalls (as practically any non-POSIX interface hacked	516	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	517	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	518	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,	519	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> -	520	so you really really should check the return value of C<aio_sendfile> -
476	fewre bytes than expected might have been transferred.	521	fewer bytes than expected might have been transferred.
477		522
478		523
479	=item aio_readahead $fh,$offset,$length, $callback->($retval)	524	=item aio_readahead $fh,$offset,$length, $callback->($retval)
480		525
481	C<aio_readahead> populates the page cache with data from a file so that	526	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	530	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	531	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	532	(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.	533	file. The current file offset of the file is left unchanged.
489		534
490	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	535	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.	536	be emulated by simply reading the data, which would have a similar effect.
492		537
493		538
494	=item aio_stat $fh_or_path, $callback->($status)	539	=item aio_stat $fh_or_path, $callback->($status)
495		540
496	=item aio_lstat $fh, $callback->($status)	541	=item aio_lstat $fh, $callback->($status)
…		…
565	namemax => 255,	610	namemax => 255,
566	frsize => 1024,	611	frsize => 1024,
567	fsid => 1810	612	fsid => 1810
568	}	613	}
569		614
		615	Here is a (likely partial - send me updates!) list of fsid values used by
		616	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		617
		618	0x0000adf5 adfs
		619	0x0000adff affs
		620	0x5346414f afs
		621	0x09041934 anon-inode filesystem
		622	0x00000187 autofs
		623	0x42465331 befs
		624	0x1badface bfs
		625	0x42494e4d binfmt_misc
		626	0x9123683e btrfs
		627	0x0027e0eb cgroupfs
		628	0xff534d42 cifs
		629	0x73757245 coda
		630	0x012ff7b7 coh
		631	0x28cd3d45 cramfs
		632	0x453dcd28 cramfs-wend (wrong endianness)
		633	0x64626720 debugfs
		634	0x00001373 devfs
		635	0x00001cd1 devpts
		636	0x0000f15f ecryptfs
		637	0x00414a53 efs
		638	0x0000137d ext
		639	0x0000ef53 ext2/ext3/ext4
		640	0x0000ef51 ext2
		641	0xf2f52010 f2fs
		642	0x00004006 fat
		643	0x65735546 fuseblk
		644	0x65735543 fusectl
		645	0x0bad1dea futexfs
		646	0x01161970 gfs2
		647	0x47504653 gpfs
		648	0x00004244 hfs
		649	0xf995e849 hpfs
		650	0x00c0ffee hostfs
		651	0x958458f6 hugetlbfs
		652	0x2bad1dea inotifyfs
		653	0x00009660 isofs
		654	0x000072b6 jffs2
		655	0x3153464a jfs
		656	0x6b414653 k-afs
		657	0x0bd00bd0 lustre
		658	0x0000137f minix
		659	0x0000138f minix 30 char names
		660	0x00002468 minix v2
		661	0x00002478 minix v2 30 char names
		662	0x00004d5a minix v3
		663	0x19800202 mqueue
		664	0x00004d44 msdos
		665	0x0000564c novell
		666	0x00006969 nfs
		667	0x6e667364 nfsd
		668	0x00003434 nilfs
		669	0x5346544e ntfs
		670	0x00009fa1 openprom
		671	0x7461636F ocfs2
		672	0x00009fa0 proc
		673	0x6165676c pstorefs
		674	0x0000002f qnx4
		675	0x68191122 qnx6
		676	0x858458f6 ramfs
		677	0x52654973 reiserfs
		678	0x00007275 romfs
		679	0x67596969 rpc_pipefs
		680	0x73636673 securityfs
		681	0xf97cff8c selinux
		682	0x0000517b smb
		683	0x534f434b sockfs
		684	0x73717368 squashfs
		685	0x62656572 sysfs
		686	0x012ff7b6 sysv2
		687	0x012ff7b5 sysv4
		688	0x01021994 tmpfs
		689	0x15013346 udf
		690	0x00011954 ufs
		691	0x54190100 ufs byteswapped
		692	0x00009fa2 usbdevfs
		693	0x01021997 v9fs
		694	0xa501fcf5 vxfs
		695	0xabba1974 xenfs
		696	0x012ff7b4 xenix
		697	0x58465342 xfs
		698	0x012fd16d xia
570		699
571	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	700	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
572		701
573	Works like perl's C<utime> function (including the special case of $atime	702	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	703	and $mtime being undef). Fractional times are supported if the underlying
…		…
602	=item aio_truncate $fh_or_path, $offset, $callback->($status)	731	=item aio_truncate $fh_or_path, $offset, $callback->($status)
603		732
604	Works like truncate(2) or ftruncate(2).	733	Works like truncate(2) or ftruncate(2).
605		734
606		735
		736	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		737
		738	Allocates or frees disk space according to the C<$mode> argument. See the
		739	linux C<fallocate> documentation for details.
		740
		741	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		742	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		743	to deallocate a file range.
		744
		745	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		746	(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
		747	C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
		748	to unshare shared blocks (see your L<fallocate(2)> manpage).
		749
		750	The file system block size used by C<fallocate> is presumably the
		751	C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
		752	can dictate other limitations.
		753
		754	If C<fallocate> isn't available or cannot be emulated (currently no
		755	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		756
		757
607	=item aio_chmod $fh_or_path, $mode, $callback->($status)	758	=item aio_chmod $fh_or_path, $mode, $callback->($status)
608		759
609	Works like perl's C<chmod> function.	760	Works like perl's C<chmod> function.
610		761
611		762
…		…
613		764
614	Asynchronously unlink (delete) a file and call the callback with the	765	Asynchronously unlink (delete) a file and call the callback with the
615	result code.	766	result code.
616		767
617		768
618	=item aio_mknod $path, $mode, $dev, $callback->($status)	769	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
619		770
620	[EXPERIMENTAL]	771	[EXPERIMENTAL]
621		772
622	Asynchronously create a device node (or fifo). See mknod(2).	773	Asynchronously create a device node (or fifo). See mknod(2).
623		774
624	The only (POSIX-) portable way of calling this function is:	775	The only (POSIX-) portable way of calling this function is:
625		776
626	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	777	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
627		778
628	See C<aio_stat> for info about some potentially helpful extra constants	779	See C<aio_stat> for info about some potentially helpful extra constants
629	and functions.	780	and functions.
630		781
631	=item aio_link $srcpath, $dstpath, $callback->($status)	782	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
638		789
639	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	790	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
640	the path C<$dstpath> and call the callback with the result code.	791	the path C<$dstpath> and call the callback with the result code.
641		792
642		793
643	=item aio_readlink $path, $callback->($link)	794	=item aio_readlink $pathname, $callback->($link)
644		795
645	Asynchronously read the symlink specified by C<$path> and pass it to	796	Asynchronously read the symlink specified by C<$path> and pass it to
646	the callback. If an error occurs, nothing or undef gets passed to the	797	the callback. If an error occurs, nothing or undef gets passed to the
647	callback.	798	callback.
648		799
649		800
650	=item aio_realpath $path, $callback->($path)	801	=item aio_realpath $pathname, $callback->($path)
651		802
652	Asynchronously make the path absolute and resolve any symlinks in	803	Asynchronously make the path absolute and resolve any symlinks in
653	C<$path>. The resulting path only consists of directories (Same as	804	C<$path>. The resulting path only consists of directories (same as
654	L<Cwd::realpath>).	805	L<Cwd::realpath>).
655		806
656	This request can be used to get the absolute path of the current working	807	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).	808	directory by passing it a path of F<.> (a single dot).
658		809
659		810
660	=item aio_rename $srcpath, $dstpath, $callback->($status)	811	=item aio_rename $srcpath, $dstpath, $callback->($status)
661		812
662	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	813	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
663	rename(2) and call the callback with the result code.	814	rename(2) and call the callback with the result code.
		815
		816	On systems that support the AIO::WD working directory abstraction
		817	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		818	of failing, C<rename> is called on the absolute path of C<$wd>.
		819
		820
		821	=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
		822
		823	Basically a version of C<aio_rename> with an additional C<$flags>
		824	argument. Calling this with C<$flags=0> is the same as calling
		825	C<aio_rename>.
		826
		827	Non-zero flags are currently only supported on GNU/Linux systems that
		828	support renameat2. Other systems fail with C<ENOSYS> in this case.
		829
		830	The following constants are available (missing ones are, as usual C<0>),
		831	see renameat2(2) for details:
		832
		833	C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
		834	and C<IO::AIO::RENAME_WHITEOUT>.
664		835
665		836
666	=item aio_mkdir $pathname, $mode, $callback->($status)	837	=item aio_mkdir $pathname, $mode, $callback->($status)
667		838
668	Asynchronously mkdir (create) a directory and call the callback with	839	Asynchronously mkdir (create) a directory and call the callback with
…		…
673	=item aio_rmdir $pathname, $callback->($status)	844	=item aio_rmdir $pathname, $callback->($status)
674		845
675	Asynchronously rmdir (delete) a directory and call the callback with the	846	Asynchronously rmdir (delete) a directory and call the callback with the
676	result code.	847	result code.
677		848
		849	On systems that support the AIO::WD working directory abstraction
		850	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		851	C<rmdir> is called on the absolute path of C<$wd>.
		852
678		853
679	=item aio_readdir $pathname, $callback->($entries)	854	=item aio_readdir $pathname, $callback->($entries)
680		855
681	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	856	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	857	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
686	array-ref with the filenames.	861	array-ref with the filenames.
687		862
688		863
689	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	864	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
690		865
691	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	866	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	867	tune behaviour and output format. In case of an error, C<$entries> will be
693	C<undef>.	868	C<undef>.
694		869
695	The flags are a combination of the following constants, ORed together (the	870	The flags are a combination of the following constants, ORed together (the
696	flags will also be passed to the callback, possibly modified):	871	flags will also be passed to the callback, possibly modified):
697		872
…		…
744		919
745	=item IO::AIO::READDIR_FOUND_UNKNOWN	920	=item IO::AIO::READDIR_FOUND_UNKNOWN
746		921
747	This flag should not be set when calling C<aio_readdirx>. Instead, it	922	This flag should not be set when calling C<aio_readdirx>. Instead, it
748	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	923	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
749	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	924	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
750	C<$type>'s are known, which can be used to speed up some algorithms.	925	C<$type>'s are known, which can be used to speed up some algorithms.
751		926
752	=back	927	=back
753		928
754		929
755	=item aio_load $path, $data, $callback->($status)	930	=item aio_load $pathname, $data, $callback->($status)
756		931
757	This is a composite request that tries to fully load the given file into	932	This is a composite request that tries to fully load the given file into
758	memory. Status is the same as with aio_read.	933	memory. Status is the same as with aio_read.
759		934
760	=cut	935	=cut
…		…
783	=item aio_copy $srcpath, $dstpath, $callback->($status)	958	=item aio_copy $srcpath, $dstpath, $callback->($status)
784		959
785	Try to copy the I<file> (directories not supported as either source or	960	Try to copy the I<file> (directories not supported as either source or
786	destination) from C<$srcpath> to C<$dstpath> and call the callback with	961	destination) from C<$srcpath> to C<$dstpath> and call the callback with
787	a status of C<0> (ok) or C<-1> (error, see C<$!>).	962	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		963
		964	Existing destination files will be truncated.
788		965
789	This is a composite request that creates the destination file with	966	This is a composite request that creates the destination file with
790	mode 0200 and copies the contents of the source file into it using	967	mode 0200 and copies the contents of the source file into it using
791	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	968	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
792	uid/gid, in that order.	969	uid/gid, in that order.
…		…
895	};	1072	};
896		1073
897	$grp	1074	$grp
898	}	1075	}
899		1076
900	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1077	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
901		1078
902	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1079	Scans a directory (similar to C<aio_readdir>) but additionally tries to
903	efficiently separate the entries of directory C<$path> into two sets of	1080	efficiently separate the entries of directory C<$path> into two sets of
904	names, directories you can recurse into (directories), and ones you cannot	1081	names, directories you can recurse into (directories), and ones you cannot
905	recurse into (everything else, including symlinks to directories).	1082	recurse into (everything else, including symlinks to directories).
…		…
936	Then entries will be sorted into likely directories a non-initial dot	1113	Then entries will be sorted into likely directories a non-initial dot
937	currently) and likely non-directories (see C<aio_readdirx>). Then every	1114	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,	1115	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	1116	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	1117	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	1118	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	1119	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	1120	data (e.g. ext2fs filetype feature), even on systems that cannot return
944	the filetype information on readdir.	1121	the filetype information on readdir.
945		1122
946	If the known number of directories (link count - 2) has been reached, the	1123	If the known number of directories (link count - 2) has been reached, the
…		…
962		1139
963	my $grp = aio_group $cb;	1140	my $grp = aio_group $cb;
964		1141
965	$maxreq = 4 if $maxreq <= 0;	1142	$maxreq = 4 if $maxreq <= 0;
966		1143
967	# stat once	1144	# get a wd object
968	aioreq_pri $pri;	1145	aioreq_pri $pri;
969	add $grp aio_stat $path, sub {	1146	add $grp aio_wd $path, sub {
		1147	$_[0]
970	return $grp->result () if $_[0];	1148	or return $grp->result ();
971	my $now = time;
972	my $hash1 = join ":", (stat _)[0,1,3,7,9];
973		1149
974	# read the directory entries	1150	my $wd = [shift, "."];
		1151
		1152	# stat once
975	aioreq_pri $pri;	1153	aioreq_pri $pri;
976	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1154	add $grp aio_stat $wd, sub {
977	my $entries = shift
978	or return $grp->result ();	1155	return $grp->result () if $_[0];
		1156	my $now = time;
		1157	my $hash1 = join ":", (stat _)[0,1,3,7,9];
979		1158
980	# stat the dir another time	1159	# read the directory entries
981	aioreq_pri $pri;	1160	aioreq_pri $pri;
		1161	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1162	my $entries = shift
		1163	or return $grp->result ();
		1164
		1165	# stat the dir another time
		1166	aioreq_pri $pri;
982	add $grp aio_stat $path, sub {	1167	add $grp aio_stat $wd, sub {
983	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1168	my $hash2 = join ":", (stat _)[0,1,3,7,9];
984		1169
985	my $ndirs;	1170	my $ndirs;
986		1171
987	# take the slow route if anything looks fishy	1172	# take the slow route if anything looks fishy
988	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1173	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
989	$ndirs = -1;	1174	$ndirs = -1;
990	} else {	1175	} else {
991	# if nlink == 2, we are finished	1176	# if nlink == 2, we are finished
992	# for non-posix-fs's, we rely on nlink < 2	1177	# for non-posix-fs's, we rely on nlink < 2
993	$ndirs = (stat _)[3] - 2	1178	$ndirs = (stat _)[3] - 2
994	or return $grp->result ([], $entries);	1179	or return $grp->result ([], $entries);
995	}	1180	}
996		1181
997	my (@dirs, @nondirs);	1182	my (@dirs, @nondirs);
998		1183
999	my $statgrp = add $grp aio_group sub {	1184	my $statgrp = add $grp aio_group sub {
1000	$grp->result (\@dirs, \@nondirs);	1185	$grp->result (\@dirs, \@nondirs);
1001	};	1186	};
1002		1187
1003	limit $statgrp $maxreq;	1188	limit $statgrp $maxreq;
1004	feed $statgrp sub {	1189	feed $statgrp sub {
1005	return unless @$entries;	1190	return unless @$entries;
1006	my $entry = shift @$entries;	1191	my $entry = shift @$entries;
1007		1192
1008	aioreq_pri $pri;	1193	aioreq_pri $pri;
		1194	$wd->[1] = "$entry/.";
1009	add $statgrp aio_stat "$path/$entry/.", sub {	1195	add $statgrp aio_stat $wd, sub {
1010	if ($_[0] < 0) {	1196	if ($_[0] < 0) {
1011	push @nondirs, $entry;	1197	push @nondirs, $entry;
1012	} else {	1198	} else {
1013	# need to check for real directory	1199	# need to check for real directory
1014	aioreq_pri $pri;	1200	aioreq_pri $pri;
		1201	$wd->[1] = $entry;
1015	add $statgrp aio_lstat "$path/$entry", sub {	1202	add $statgrp aio_lstat $wd, sub {
1016	if (-d _) {	1203	if (-d _) {
1017	push @dirs, $entry;	1204	push @dirs, $entry;
1018		1205
1019	unless (--$ndirs) {	1206	unless (--$ndirs) {
1020	push @nondirs, @$entries;	1207	push @nondirs, @$entries;
1021	feed $statgrp;	1208	feed $statgrp;
		1209	}
		1210	} else {
		1211	push @nondirs, $entry;
1022	}	1212	}
1023	} else {
1024	push @nondirs, $entry;
1025	}	1213	}
1026	}	1214	}
1027	}	1215	};
1028	};	1216	};
1029	};	1217	};
1030	};	1218	};
1031	};	1219	};
1032	};	1220	};
1033		1221
1034	$grp	1222	$grp
1035	}	1223	}
1036		1224
1037	=item aio_rmtree $path, $callback->($status)	1225	=item aio_rmtree $pathname, $callback->($status)
1038		1226
1039	Delete a directory tree starting (and including) C<$path>, return the	1227	Delete a directory tree starting (and including) C<$path>, return the
1040	status of the final C<rmdir> only. This is a composite request that	1228	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	1229	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1042	everything else.	1230	everything else.
1043		1231
1044	=cut	1232	=cut
1045		1233
…		…
1067	};	1255	};
1068		1256
1069	$grp	1257	$grp
1070	}	1258	}
1071		1259
		1260	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1261
		1262	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1263
		1264	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1265	they execute asynchronously and pass the return value to the callback.
		1266
		1267	Both calls can be used for a lot of things, some of which make more sense
		1268	to run asynchronously in their own thread, while some others make less
		1269	sense. For example, calls that block waiting for external events, such
		1270	as locking, will also lock down an I/O thread while it is waiting, which
		1271	can deadlock the whole I/O system. At the same time, there might be no
		1272	alternative to using a thread to wait.
		1273
		1274	So in general, you should only use these calls for things that do
		1275	(filesystem) I/O, not for things that wait for other events (network,
		1276	other processes), although if you are careful and know what you are doing,
		1277	you still can.
		1278
		1279	The following constants are available (missing ones are, as usual C<0>):
		1280
		1281	C<F_DUPFD_CLOEXEC>,
		1282
		1283	C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
		1284
		1285	C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
		1286
		1287	C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
		1288	C<FS_IOC_FIEMAP>.
		1289
		1290	C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
		1291	C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
		1292
		1293	C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
		1294	C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
		1295	C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
		1296	C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
		1297	C<FS_FL_USER_MODIFIABLE>.
		1298
		1299	C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
		1300	C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
		1301	C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
		1302	C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
		1303
1072	=item aio_sync $callback->($status)	1304	=item aio_sync $callback->($status)
1073		1305
1074	Asynchronously call sync and call the callback when finished.	1306	Asynchronously call sync and call the callback when finished.
1075		1307
1076	=item aio_fsync $fh, $callback->($status)	1308	=item aio_fsync $fh, $callback->($status)
…		…
1083	Asynchronously call fdatasync on the given filehandle and call the	1315	Asynchronously call fdatasync on the given filehandle and call the
1084	callback with the fdatasync result code.	1316	callback with the fdatasync result code.
1085		1317
1086	If this call isn't available because your OS lacks it or it couldn't be	1318	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.	1319	detected, it will be emulated by calling C<fsync> instead.
		1320
		1321	=item aio_syncfs $fh, $callback->($status)
		1322
		1323	Asynchronously call the syncfs syscall to sync the filesystem associated
		1324	to the given filehandle and call the callback with the syncfs result
		1325	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1326	errno to C<ENOSYS> nevertheless.
1088		1327
1089	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1328	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1090		1329
1091	Sync the data portion of the file specified by C<$offset> and C<$length>	1330	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	1331	to disk (but NOT the metadata), by calling the Linux-specific
…		…
1096	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1335	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1097	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1336	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1098	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1337	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1099	manpage for details.	1338	manpage for details.
1100		1339
1101	=item aio_pathsync $path, $callback->($status)	1340	=item aio_pathsync $pathname, $callback->($status)
1102		1341
1103	This request tries to open, fsync and close the given path. This is a	1342	This request tries to open, fsync and close the given path. This is a
1104	composite request intended to sync directories after directory operations	1343	composite request intended to sync directories after directory operations
1105	(E.g. rename). This might not work on all operating systems or have any	1344	(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	1345	specific effect, but usually it makes sure that directory changes get
…		…
1137	};	1376	};
1138		1377
1139	$grp	1378	$grp
1140	}	1379	}
1141		1380
1142	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1381	=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1143		1382
1144	This is a rather advanced IO::AIO call, which only works on mmap(2)ed	1383	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	1384	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	1385	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	1386	scalar must only be modified in-place while an aio operation is pending on
…		…
1149		1388
1150	It calls the C<msync> function of your OS, if available, with the memory	1389	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	1390	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>	1391	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	1392	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	1393	either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1155	C<IO::AIO::MS_SYNC>.	1394	C<IO::AIO::MS_INVALIDATE>.
1156		1395
1157	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	1396	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1158		1397
1159	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1398	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1160	scalars.	1399	scalars.
1161		1400
1162	It touches (reads or writes) all memory pages in the specified	1401	It touches (reads or writes) all memory pages in the specified
1163	range inside the scalar. All caveats and parameters are the same	1402	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	1403	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	1404	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	1405	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1167	writing an octet from it, which dirties the page).	1406	writing an octet from it, which dirties the page).
1168		1407
1169	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1408	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1170		1409
1171	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1410	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1202	documented under L<MISCELLANEOUS FUNCTIONS>.	1441	documented under L<MISCELLANEOUS FUNCTIONS>.
1203		1442
1204	Example: asynchronously lock all current and future pages into memory.	1443	Example: asynchronously lock all current and future pages into memory.
1205		1444
1206	aio_mlockall IO::AIO::MCL_FUTURE;	1445	aio_mlockall IO::AIO::MCL_FUTURE;
		1446
		1447	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1448
		1449	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1450	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1451	the ioctl is not available on your OS, then this request will fail with
		1452	C<ENOSYS>.
		1453
		1454	C<$start> is the starting offset to query extents for, C<$length> is the
		1455	size of the range to query - if it is C<undef>, then the whole file will
		1456	be queried.
		1457
		1458	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1459	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1460	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1461	the data portion.
		1462
		1463	C<$count> is the maximum number of extent records to return. If it is
		1464	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1465	case, if it is C<0>, then the callback receives the number of extents
		1466	instead of the extents themselves (which is unreliable, see below).
		1467
		1468	If an error occurs, the callback receives no arguments. The special
		1469	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1470
		1471	Otherwise, the callback receives an array reference with extent
		1472	structures. Each extent structure is an array reference itself, with the
		1473	following members:
		1474
		1475	[$logical, $physical, $length, $flags]
		1476
		1477	Flags is any combination of the following flag values (typically either C<0>
		1478	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1479
		1480	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1481	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1482	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1483	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1484	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1485	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1486
		1487	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1488	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1489	it to return all extents of a range for files with large number of
		1490	extents. The code works around all these issues if C<$count> is undef.
1207		1491
1208	=item aio_group $callback->(...)	1492	=item aio_group $callback->(...)
1209		1493
1210	This is a very special aio request: Instead of doing something, it is a	1494	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	1495	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	1532	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	1533	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.	1534	except to put your application under artificial I/O pressure.
1251		1535
1252	=back	1536	=back
		1537
		1538
		1539	=head2 IO::AIO::WD - multiple working directories
		1540
		1541	Your process only has one current working directory, which is used by all
		1542	threads. This makes it hard to use relative paths (some other component
		1543	could call C<chdir> at any time, and it is hard to control when the path
		1544	will be used by IO::AIO).
		1545
		1546	One solution for this is to always use absolute paths. This usually works,
		1547	but can be quite slow (the kernel has to walk the whole path on every
		1548	access), and can also be a hassle to implement.
		1549
		1550	Newer POSIX systems have a number of functions (openat, fdopendir,
		1551	futimensat and so on) that make it possible to specify working directories
		1552	per operation.
		1553
		1554	For portability, and because the clowns who "designed", or shall I write,
		1555	perpetrated this new interface were obviously half-drunk, this abstraction
		1556	cannot be perfect, though.
		1557
		1558	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1559	object. This object stores the canonicalised, absolute version of the
		1560	path, and on systems that allow it, also a directory file descriptor.
		1561
		1562	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1563	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1564	object and a pathname instead (or the IO::AIO::WD object alone, which
		1565	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1566	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1567	to that IO::AIO::WD object.
		1568
		1569	For example, to get a wd object for F</etc> and then stat F<passwd>
		1570	inside, you would write:
		1571
		1572	aio_wd "/etc", sub {
		1573	my $etcdir = shift;
		1574
		1575	# although $etcdir can be undef on error, there is generally no reason
		1576	# to check for errors here, as aio_stat will fail with ENOENT
		1577	# when $etcdir is undef.
		1578
		1579	aio_stat [$etcdir, "passwd"], sub {
		1580	# yay
		1581	};
		1582	};
		1583
		1584	The fact that C<aio_wd> is a request and not a normal function shows that
		1585	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1586	which is why it is done asynchronously.
		1587
		1588	To stat the directory obtained with C<aio_wd> above, one could write
		1589	either of the following three request calls:
		1590
		1591	aio_lstat "/etc" , sub { ... # pathname as normal string
		1592	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1593	aio_lstat $wd , sub { ... # shorthand for the previous
		1594
		1595	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1596	object and the pathname string, so you could write the following without
		1597	causing any issues due to C<$path> getting reused:
		1598
		1599	my $path = [$wd, undef];
		1600
		1601	for my $name (qw(abc def ghi)) {
		1602	$path->[1] = $name;
		1603	aio_stat $path, sub {
		1604	# ...
		1605	};
		1606	}
		1607
		1608	There are some caveats: when directories get renamed (or deleted), the
		1609	pathname string doesn't change, so will point to the new directory (or
		1610	nowhere at all), while the directory fd, if available on the system,
		1611	will still point to the original directory. Most functions accepting a
		1612	pathname will use the directory fd on newer systems, and the string on
		1613	older systems. Some functions (such as realpath) will always rely on the
		1614	string form of the pathname.
		1615
		1616	So this functionality is mainly useful to get some protection against
		1617	C<chdir>, to easily get an absolute path out of a relative path for future
		1618	reference, and to speed up doing many operations in the same directory
		1619	(e.g. when stat'ing all files in a directory).
		1620
		1621	The following functions implement this working directory abstraction:
		1622
		1623	=over 4
		1624
		1625	=item aio_wd $pathname, $callback->($wd)
		1626
		1627	Asynchonously canonicalise the given pathname and convert it to an
		1628	IO::AIO::WD object representing it. If possible and supported on the
		1629	system, also open a directory fd to speed up pathname resolution relative
		1630	to this working directory.
		1631
		1632	If something goes wrong, then C<undef> is passwd to the callback instead
		1633	of a working directory object and C<$!> is set appropriately. Since
		1634	passing C<undef> as working directory component of a pathname fails the
		1635	request with C<ENOENT>, there is often no need for error checking in the
		1636	C<aio_wd> callback, as future requests using the value will fail in the
		1637	expected way.
		1638
		1639	=item IO::AIO::CWD
		1640
		1641	This is a compiletime constant (object) that represents the process
		1642	current working directory.
		1643
		1644	Specifying this object as working directory object for a pathname is as if
		1645	the pathname would be specified directly, without a directory object. For
		1646	example, these calls are functionally identical:
		1647
		1648	aio_stat "somefile", sub { ... };
		1649	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1650
		1651	=back
		1652
		1653	To recover the path associated with an IO::AIO::WD object, you can use
		1654	C<aio_realpath>:
		1655
		1656	aio_realpath $wd, sub {
		1657	warn "path is $_[0]\n";
		1658	};
		1659
		1660	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1661	sometimes, fall back to using an absolue path.
1253		1662
1254	=head2 IO::AIO::REQ CLASS	1663	=head2 IO::AIO::REQ CLASS
1255		1664
1256	All non-aggregate C<aio_*> functions return an object of this class when	1665	All non-aggregate C<aio_*> functions return an object of this class when
1257	called in non-void context.	1666	called in non-void context.
…		…
1375		1784
1376	Sets a feeder/generator on this group: every group can have an attached	1785	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,	1786	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,	1787	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,	1788	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,	1789	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1381	delaying any later requests for a long time.	1790	requests, delaying any later requests for a long time.
1382		1791
1383	To avoid this, and allow incremental generation of requests, you can	1792	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	1793	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>,	1794	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	1795	below) requests active in the group itself and is expected to queue more
…		…
1435		1844
1436	See C<poll_cb> for an example.	1845	See C<poll_cb> for an example.
1437		1846
1438	=item IO::AIO::poll_cb	1847	=item IO::AIO::poll_cb
1439		1848
1440	Process some outstanding events on the result pipe. You have to call	1849	Process some requests that have reached the result phase (i.e. they have
		1850	been executed but the results are not yet reported). You have to call
		1851	this "regularly" to finish outstanding requests.
		1852
1441	this regularly. Returns C<0> if all events could be processed (or there	1853	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	1854	events to process), or C<-1> if it returned earlier for whatever
1443	reason. Returns immediately when no events are outstanding. The amount of	1855	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	1856	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1445	C<IO::AIO::max_poll_time>.	1857	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1446		1858
1447	If not all requests were processed for whatever reason, the filehandle	1859	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	1860	descriptor will still be ready when C<poll_cb> returns, so normally you
1449	do anything special to have it called later.	1861	don't have to do anything special to have it called later.
1450		1862
1451	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes	1863	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	1864	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	1865	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	1866	available and not just when the loop is finished and the event loop takes
…		…
1463	poll => 'r', async => 1,	1875	poll => 'r', async => 1,
1464	cb => \&IO::AIO::poll_cb);	1876	cb => \&IO::AIO::poll_cb);
1465		1877
1466	=item IO::AIO::poll_wait	1878	=item IO::AIO::poll_wait
1467		1879
1468	If there are any outstanding requests and none of them in the result	1880	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	1881	requests are outstanding anymore.
1470	does a C<select> on the filehandle. This is useful if you want to	1882
1471	synchronously wait for some requests to finish).	1883	This is useful if you want to synchronously wait for some requests to
		1884	become ready, without actually handling them.
1472		1885
1473	See C<nreqs> for an example.	1886	See C<nreqs> for an example.
1474		1887
1475	=item IO::AIO::poll	1888	=item IO::AIO::poll
1476		1889
…		…
1597		2010
1598	This is a very bad function to use in interactive programs because it	2011	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	2012	blocks, and a bad way to reduce concurrency because it is inexact: Better
1600	use an C<aio_group> together with a feed callback.	2013	use an C<aio_group> together with a feed callback.
1601		2014
1602	It's main use is in scripts without an event loop - when you want to stat	2015	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:	2016	a lot of files, you can write something like this:
1604		2017
1605	IO::AIO::max_outstanding 32;	2018	IO::AIO::max_outstanding 32;
1606		2019
1607	for my $path (...) {	2020	for my $path (...) {
1608	aio_stat $path , ...;	2021	aio_stat $path , ...;
…		…
1647		2060
1648	=back	2061	=back
1649		2062
1650	=head3 MISCELLANEOUS FUNCTIONS	2063	=head3 MISCELLANEOUS FUNCTIONS
1651		2064
1652	IO::AIO implements some functions that might be useful, but are not	2065	IO::AIO implements some functions that are useful when you want to use
1653	asynchronous.	2066	some "Advanced I/O" function not available to in Perl, without going the
		2067	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2068	counterpart.
1654		2069
1655	=over 4	2070	=over 4
		2071
		2072	=item $numfd = IO::AIO::get_fdlimit
		2073
		2074	Tries to find the current file descriptor limit and returns it, or
		2075	C<undef> and sets C<$!> in case of an error. The limit is one larger than
		2076	the highest valid file descriptor number.
		2077
		2078	=item IO::AIO::min_fdlimit [$numfd]
		2079
		2080	Try to increase the current file descriptor limit(s) to at least C<$numfd>
		2081	by changing the soft or hard file descriptor resource limit. If C<$numfd>
		2082	is missing, it will try to set a very high limit, although this is not
		2083	recommended when you know the actual minimum that you require.
		2084
		2085	If the limit cannot be raised enough, the function makes a best-effort
		2086	attempt to increase the limit as much as possible, using various
		2087	tricks, while still failing. You can query the resulting limit using
		2088	C<IO::AIO::get_fdlimit>.
		2089
		2090	If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
		2091	true.
1656		2092
1657	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2093	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1658		2094
1659	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,	2095	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1660	but is blocking (this makes most sense if you know the input data is	2096	but is blocking (this makes most sense if you know the input data is
…		…
1665		2101
1666	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2102	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1667		2103
1668	Simply calls the C<posix_fadvise> function (see its	2104	Simply calls the C<posix_fadvise> function (see its
1669	manpage for details). The following advice constants are	2105	manpage for details). The following advice constants are
1670	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2106	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1671	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2107	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1672	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2108	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1673		2109
1674	On systems that do not implement C<posix_fadvise>, this function returns	2110	On systems that do not implement C<posix_fadvise>, this function returns
1675	ENOSYS, otherwise the return value of C<posix_fadvise>.	2111	ENOSYS, otherwise the return value of C<posix_fadvise>.
1676		2112
1677	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2113	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1678		2114
1679	Simply calls the C<posix_madvise> function (see its	2115	Simply calls the C<posix_madvise> function (see its
1680	manpage for details). The following advice constants are	2116	manpage for details). The following advice constants are
1681	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2117	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1682	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2118	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
		2119	C<IO::AIO::MADV_DONTNEED>.
		2120
		2121	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2122	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2123	will be reduced to fit into the C<$scalar>.
1683		2124
1684	On systems that do not implement C<posix_madvise>, this function returns	2125	On systems that do not implement C<posix_madvise>, this function returns
1685	ENOSYS, otherwise the return value of C<posix_madvise>.	2126	ENOSYS, otherwise the return value of C<posix_madvise>.
1686		2127
1687	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2128	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1688		2129
1689	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2130	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1690	$scalar (see its manpage for details). The following protect	2131	$scalar (see its manpage for details). The following protect
1691	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2132	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1692	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2133	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		2134
		2135	If C<$offset> is negative, counts from the end. If C<$length> is negative,
		2136	the remaining length of the C<$scalar> is used. If possible, C<$length>
		2137	will be reduced to fit into the C<$scalar>.
1693		2138
1694	On systems that do not implement C<mprotect>, this function returns	2139	On systems that do not implement C<mprotect>, this function returns
1695	ENOSYS, otherwise the return value of C<mprotect>.	2140	ENOSYS, otherwise the return value of C<mprotect>.
1696		2141
1697	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2142	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1698		2143
1699	Memory-maps a file (or anonymous memory range) and attaches it to the	2144	Memory-maps a file (or anonymous memory range) and attaches it to the
1700	given C<$scalar>, which will act like a string scalar.	2145	given C<$scalar>, which will act like a string scalar. Returns true on
		2146	success, and false otherwise.
1701		2147
		2148	The scalar must exist, but its contents do not matter - this means you
		2149	cannot use a nonexistant array or hash element. When in doubt, C<undef>
		2150	the scalar first.
		2151
1702	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2152	The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1703	change the string length, and most read-only operations such as copying it	2153	which don't change the string length, and most read-only operations such
1704	or searching it with regexes and so on.	2154	as copying it or searching it with regexes and so on.
1705		2155
1706	Anything else is unsafe and will, at best, result in memory leaks.	2156	Anything else is unsafe and will, at best, result in memory leaks.
1707		2157
1708	The memory map associated with the C<$scalar> is automatically removed	2158	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	2159	when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1710	C<IO::AIO::munmap> functions are called.	2160	or C<IO::AIO::munmap> functions are called on it.
1711		2161
1712	This calls the C<mmap>(2) function internally. See your system's manual	2162	This calls the C<mmap>(2) function internally. See your system's manual
1713	page for details on the C<$length>, C<$prot> and C<$flags> parameters.	2163	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1714		2164
1715	The C<$length> must be larger than zero and smaller than the actual	2165	The C<$length> must be larger than zero and smaller than the actual
1716	filesize.	2166	filesize.
1717		2167
1718	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2168	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1719	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2169	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1720		2170
1721	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2171	C<$flags> can be a combination of
1722	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2172	C<IO::AIO::MAP_SHARED> or
1723	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2173	C<IO::AIO::MAP_PRIVATE>,
		2174	or a number of system-specific flags (when not available, the are C<0>):
1724	(which is set to C<MAP_ANON> if your system only provides this	2175	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1725	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2176	C<IO::AIO::MAP_LOCKED>,
1726	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2177	C<IO::AIO::MAP_NORESERVE>,
		2178	C<IO::AIO::MAP_POPULATE>,
1727	C<IO::AIO::MAP_NONBLOCK>	2179	C<IO::AIO::MAP_NONBLOCK>,
		2180	C<IO::AIO::MAP_FIXED>,
		2181	C<IO::AIO::MAP_GROWSDOWN>,
		2182	C<IO::AIO::MAP_32BIT>,
		2183	C<IO::AIO::MAP_HUGETLB> or
		2184	C<IO::AIO::MAP_STACK>.
1728		2185
1729	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2186	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1730		2187
1731	C<$offset> is the offset from the start of the file - it generally must be	2188	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>.	2189	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1757		2214
1758	Calls the C<munlockall> function.	2215	Calls the C<munlockall> function.
1759		2216
1760	On systems that do not implement C<munlockall>, this function returns	2217	On systems that do not implement C<munlockall>, this function returns
1761	ENOSYS, otherwise the return value of C<munlockall>.	2218	ENOSYS, otherwise the return value of C<munlockall>.
		2219
		2220	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2221
		2222	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2223	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2224	should be the file offset.
		2225
		2226	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2227	silently corrupt the data in this case.
		2228
		2229	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2230	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2231	C<IO::AIO::SPLICE_F_GIFT>.
		2232
		2233	See the C<splice(2)> manpage for details.
		2234
		2235	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2236
		2237	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2238	description for C<IO::AIO::splice> above for details.
		2239
		2240	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2241
		2242	Attempts to query or change the pipe buffer size. Obviously works only
		2243	on pipes, and currently works only on GNU/Linux systems, and fails with
		2244	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2245	size on other systems, drop me a note.
		2246
		2247	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2248
		2249	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2250	C<$flags> is missing or C<0>, then this should be the same as a call to
		2251	perl's built-in C<pipe> function and create a new pipe, and works on
		2252	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2253	(..., 4096, O_BINARY)>.
		2254
		2255	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2256	the given flags (Linux 2.6.27, glibc 2.9).
		2257
		2258	On success, the read and write file handles are returned.
		2259
		2260	On error, nothing will be returned. If the pipe2 syscall is missing and
		2261	C<$flags> is non-zero, fails with C<ENOSYS>.
		2262
		2263	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2264	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2265	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1762		2266
1763	=back	2267	=back
1764		2268
1765	=cut	2269	=cut
1766		2270
…		…
1804	=head2 FORK BEHAVIOUR	2308	=head2 FORK BEHAVIOUR
1805		2309
1806	Usage of pthreads in a program changes the semantics of fork	2310	Usage of pthreads in a program changes the semantics of fork
1807	considerably. Specifically, only async-safe functions can be called after	2311	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	2312	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,	2313	with defined behaviour in perl if pthreads are involved. IO::AIO uses
1810	but many other extensions and (for inexplicable reasons) perl itself often	2314	pthreads, so this applies, but many other extensions and (for inexplicable
1811	is linked against pthreads, so this limitation applies.	2315	reasons) perl itself often is linked against pthreads, so this limitation
		2316	applies to quite a lot of perls.
1812		2317
1813	Some operating systems have extensions that allow safe use of fork, and	2318	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	2319	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	2320	using IO::AIO in the child is not.
1816	to POSIX.	2321
		2322	You might get around by not I<using> IO::AIO before (or after)
		2323	forking. You could also try to call the L<IO::AIO::reinit> function in the
		2324	child:
		2325
		2326	=over 4
		2327
		2328	=item IO::AIO::reinit
		2329
		2330	Abandons all current requests and I/O threads and simply reinitialises all
		2331	data structures. This is not an operation supported by any standards, but
		2332	happens to work on GNU/Linux and some newer BSD systems.
		2333
		2334	The only reasonable use for this function is to call it after forking, if
		2335	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2336	the process will result in undefined behaviour. Calling it at any time
		2337	will also result in any undefined (by POSIX) behaviour.
		2338
		2339	=back
1817		2340
1818	=head2 MEMORY USAGE	2341	=head2 MEMORY USAGE
1819		2342
1820	Per-request usage:	2343	Per-request usage:
1821		2344

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs. Revision 1.276 by root, Fri Sep 22 05:24:41 2017 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs.
Revision 1.276 by root, Fri Sep 22 05:24:41 2017 UTC