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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.185 by root, Sat Dec 11 19:06:07 2010 UTC vs.
Revision 1.262 by root, Thu Jun 9 03:15:37 2016 UTC

…		…
68	=head2 EXAMPLE	68	=head2 EXAMPLE
69		69
70	This is a simple example that uses the EV module and loads	70	This is a simple example that uses the EV module and loads
71	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
72		72
73	use Fcntl;
74	use EV;	73	use EV;
75	use IO::AIO;	74	use IO::AIO;
76		75
77	# register the IO::AIO callback with EV	76	# register the IO::AIO callback with EV
78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;	77	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
…		…
95		94
96	# file contents now in $contents	95	# file contents now in $contents
97	print $contents;	96	print $contents;
98		97
99	# exit event loop and program	98	# exit event loop and program
100	EV::unloop;	99	EV::break;
101	};	100	};
102	};	101	};
103		102
104	# possibly queue up other requests, or open GUI windows,	103	# possibly queue up other requests, or open GUI windows,
105	# check for sockets etc. etc.	104	# check for sockets etc. etc.
106		105
107	# process events as long as there are some:	106	# process events as long as there are some:
108	EV::loop;	107	EV::run;
109		108
110	=head1 REQUEST ANATOMY AND LIFETIME	109	=head1 REQUEST ANATOMY AND LIFETIME
111		110
112	Every C<aio_*> function creates a request. which is a C data structure not	111	Every C<aio_*> function creates a request. which is a C data structure not
113	directly visible to Perl.	112	directly visible to Perl.
…		…
168	use common::sense;	167	use common::sense;
169		168
170	use base 'Exporter';	169	use base 'Exporter';
171		170
172	BEGIN {	171	BEGIN {
173	our $VERSION = '3.7';	172	our $VERSION = 4.34;
174		173
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	174	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	175	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	176	aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	177	aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
		178	aio_pathsync aio_readahead aio_fiemap aio_allocate
179	aio_rename aio_link aio_move aio_copy aio_group	179	aio_rename aio_link aio_move aio_copy aio_group
180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181	aio_chmod aio_utime aio_truncate	181	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_mlock aio_mlockall	182	aio_msync aio_mtouch aio_mlock aio_mlockall
183	aio_statvfs);	183	aio_statvfs
		184	aio_wd);
184		185
185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
187	min_parallel max_parallel max_idle	188	min_parallel max_parallel max_idle idle_timeout
188	nreqs nready npending nthreads	189	nreqs nready npending nthreads
189	max_poll_time max_poll_reqs	190	max_poll_time max_poll_reqs
190	sendfile fadvise madvise	191	sendfile fadvise madvise
191	mmap munmap munlock munlockall);	192	mmap munmap munlock munlockall);
192		193
…		…
200		201
201	=head1 FUNCTIONS	202	=head1 FUNCTIONS
202		203
203	=head2 QUICK OVERVIEW	204	=head2 QUICK OVERVIEW
204		205
205	This section simply lists the prototypes of the most important functions	206	This section simply lists the prototypes most of the functions for
206	for quick reference. See the following sections for function-by-function	207	quick reference. See the following sections for function-by-function
207	documentation.	208	documentation.
208		209
		210	aio_wd $pathname, $callback->($wd)
209	aio_open $pathname, $flags, $mode, $callback->($fh)	211	aio_open $pathname, $flags, $mode, $callback->($fh)
210	aio_close $fh, $callback->($status)	212	aio_close $fh, $callback->($status)
		213	aio_seek $fh,$offset,$whence, $callback->($offs)
211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214	aio_readahead $fh,$offset,$length, $callback->($retval)	217	aio_readahead $fh,$offset,$length, $callback->($retval)
215	aio_stat $fh_or_path, $callback->($status)	218	aio_stat $fh_or_path, $callback->($status)
216	aio_lstat $fh, $callback->($status)	219	aio_lstat $fh, $callback->($status)
217	aio_statvfs $fh_or_path, $callback->($statvfs)	220	aio_statvfs $fh_or_path, $callback->($statvfs)
218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		223	aio_chmod $fh_or_path, $mode, $callback->($status)
220	aio_truncate $fh_or_path, $offset, $callback->($status)	224	aio_truncate $fh_or_path, $offset, $callback->($status)
221	aio_chmod $fh_or_path, $mode, $callback->($status)	225	aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		226	aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
222	aio_unlink $pathname, $callback->($status)	227	aio_unlink $pathname, $callback->($status)
223	aio_mknod $path, $mode, $dev, $callback->($status)	228	aio_mknod $pathname, $mode, $dev, $callback->($status)
224	aio_link $srcpath, $dstpath, $callback->($status)	229	aio_link $srcpath, $dstpath, $callback->($status)
225	aio_symlink $srcpath, $dstpath, $callback->($status)	230	aio_symlink $srcpath, $dstpath, $callback->($status)
226	aio_readlink $path, $callback->($link)	231	aio_readlink $pathname, $callback->($link)
		232	aio_realpath $pathname, $callback->($path)
227	aio_rename $srcpath, $dstpath, $callback->($status)	233	aio_rename $srcpath, $dstpath, $callback->($status)
228	aio_mkdir $pathname, $mode, $callback->($status)	234	aio_mkdir $pathname, $mode, $callback->($status)
229	aio_rmdir $pathname, $callback->($status)	235	aio_rmdir $pathname, $callback->($status)
230	aio_readdir $pathname, $callback->($entries)	236	aio_readdir $pathname, $callback->($entries)
231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	237	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	238	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	239	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		240	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
234	aio_load $path, $data, $callback->($status)	241	aio_load $pathname, $data, $callback->($status)
235	aio_copy $srcpath, $dstpath, $callback->($status)	242	aio_copy $srcpath, $dstpath, $callback->($status)
236	aio_move $srcpath, $dstpath, $callback->($status)	243	aio_move $srcpath, $dstpath, $callback->($status)
237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238	aio_rmtree $path, $callback->($status)	244	aio_rmtree $pathname, $callback->($status)
		245	aio_fcntl $fh, $cmd, $arg, $callback->($status)
		246	aio_ioctl $fh, $request, $buf, $callback->($status)
239	aio_sync $callback->($status)	247	aio_sync $callback->($status)
		248	aio_syncfs $fh, $callback->($status)
240	aio_fsync $fh, $callback->($status)	249	aio_fsync $fh, $callback->($status)
241	aio_fdatasync $fh, $callback->($status)	250	aio_fdatasync $fh, $callback->($status)
242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	251	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243	aio_pathsync $path, $callback->($status)	252	aio_pathsync $pathname, $callback->($status)
244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	253	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	254	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	255	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247	aio_mlockall $flags, $callback->($status)	256	aio_mlockall $flags, $callback->($status)
248	aio_group $callback->(...)	257	aio_group $callback->(...)
…		…
258	IO::AIO::max_poll_reqs $nreqs	267	IO::AIO::max_poll_reqs $nreqs
259	IO::AIO::max_poll_time $seconds	268	IO::AIO::max_poll_time $seconds
260	IO::AIO::min_parallel $nthreads	269	IO::AIO::min_parallel $nthreads
261	IO::AIO::max_parallel $nthreads	270	IO::AIO::max_parallel $nthreads
262	IO::AIO::max_idle $nthreads	271	IO::AIO::max_idle $nthreads
		272	IO::AIO::idle_timeout $seconds
263	IO::AIO::max_outstanding $maxreqs	273	IO::AIO::max_outstanding $maxreqs
264	IO::AIO::nreqs	274	IO::AIO::nreqs
265	IO::AIO::nready	275	IO::AIO::nready
266	IO::AIO::npending	276	IO::AIO::npending
267		277
268	IO::AIO::sendfile $ofh, $ifh, $offset, $count	278	IO::AIO::sendfile $ofh, $ifh, $offset, $count
269	IO::AIO::fadvise $fh, $offset, $len, $advice	279	IO::AIO::fadvise $fh, $offset, $len, $advice
		280	IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
		281	IO::AIO::munmap $scalar
270	IO::AIO::madvise $scalar, $offset, $length, $advice	282	IO::AIO::madvise $scalar, $offset, $length, $advice
271	IO::AIO::mprotect $scalar, $offset, $length, $protect	283	IO::AIO::mprotect $scalar, $offset, $length, $protect
272	IO::AIO::munlock $scalar, $offset = 0, $length = undef	284	IO::AIO::munlock $scalar, $offset = 0, $length = undef
273	IO::AIO::munlockall	285	IO::AIO::munlockall
274		286
275	=head2 AIO REQUEST FUNCTIONS	287	=head2 API NOTES
276		288
277	All the C<aio_*> calls are more or less thin wrappers around the syscall	289	All the C<aio_*> calls are more or less thin wrappers around the syscall
278	with the same name (sans C<aio_>). The arguments are similar or identical,	290	with the same name (sans C<aio_>). The arguments are similar or identical,
279	and they all accept an additional (and optional) C<$callback> argument	291	and they all accept an additional (and optional) C<$callback> argument
280	which must be a code reference. This code reference will get called with	292	which must be a code reference. This code reference will be called after
281	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	293	the syscall has been executed in an asynchronous fashion. The results
282	perl, which usually delivers "false") as its sole argument after the given	294	of the request will be passed as arguments to the callback (and, if an
283	syscall has been executed asynchronously.	295	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		296	most syscalls return C<-1> on error, unlike perl, which usually delivers
		297	"false").
		298
		299	Some requests (such as C<aio_readdir>) pass the actual results and
		300	communicate failures by passing C<undef>.
284		301
285	All functions expecting a filehandle keep a copy of the filehandle	302	All functions expecting a filehandle keep a copy of the filehandle
286	internally until the request has finished.	303	internally until the request has finished.
287		304
288	All functions return request objects of type L<IO::AIO::REQ> that allow	305	All functions return request objects of type L<IO::AIO::REQ> that allow
289	further manipulation of those requests while they are in-flight.	306	further manipulation of those requests while they are in-flight.
290		307
291	The pathnames you pass to these routines I<must> be absolute and	308	The pathnames you pass to these routines I<should> be absolute. The
292	encoded as octets. The reason for the former is that at the time the	309	reason for this is that at the time the request is being executed, the
293	request is being executed, the current working directory could have	310	current working directory could have changed. Alternatively, you can
294	changed. Alternatively, you can make sure that you never change the	311	make sure that you never change the current working directory anywhere
295	current working directory anywhere in the program and then use relative	312	in the program and then use relative paths. You can also take advantage
296	paths.	313	of IO::AIOs working directory abstraction, that lets you specify paths
		314	relative to some previously-opened "working directory object" - see the
		315	description of the C<IO::AIO::WD> class later in this document.
297		316
298	To encode pathnames as octets, either make sure you either: a) always pass	317	To encode pathnames as octets, either make sure you either: a) always pass
299	in filenames you got from outside (command line, readdir etc.) without	318	in filenames you got from outside (command line, readdir etc.) without
300	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	319	tinkering, b) are in your native filesystem encoding, c) use the Encode
301	your pathnames to the locale (or other) encoding in effect in the user	320	module and encode your pathnames to the locale (or other) encoding in
302	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	321	effect in the user environment, d) use Glib::filename_from_unicode on
303	use something else to ensure your scalar has the correct contents.	322	unicode filenames or e) use something else to ensure your scalar has the
		323	correct contents.
304		324
305	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	325	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
306	handles correctly whether it is set or not.	326	handles correctly whether it is set or not.
		327
		328	=head2 AIO REQUEST FUNCTIONS
307		329
308	=over 4	330	=over 4
309		331
310	=item $prev_pri = aioreq_pri [$pri]	332	=item $prev_pri = aioreq_pri [$pri]
311		333
…		…
341		363
342		364
343	=item aio_open $pathname, $flags, $mode, $callback->($fh)	365	=item aio_open $pathname, $flags, $mode, $callback->($fh)
344		366
345	Asynchronously open or create a file and call the callback with a newly	367	Asynchronously open or create a file and call the callback with a newly
346	created filehandle for the file.	368	created filehandle for the file (or C<undef> in case of an error).
347		369
348	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	370	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
349	for an explanation.	371	for an explanation.
350		372
351	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	373	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
367	} else {	389	} else {
368	die "open failed: $!\n";	390	die "open failed: $!\n";
369	}	391	}
370	};	392	};
371		393
		394	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		395	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		396	following POSIX and non-POSIX constants are available (missing ones on
		397	your system are, as usual, C<0>):
		398
		399	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		400	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		401	C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
		402
372		403
373	=item aio_close $fh, $callback->($status)	404	=item aio_close $fh, $callback->($status)
374		405
375	Asynchronously close a file and call the callback with the result	406	Asynchronously close a file and call the callback with the result
376	code.	407	code.
…		…
384		415
385	Or in other words: the file descriptor will be closed, but it will not be	416	Or in other words: the file descriptor will be closed, but it will not be
386	free for reuse until the perl filehandle is closed.	417	free for reuse until the perl filehandle is closed.
387		418
388	=cut	419	=cut
		420
		421	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		422
		423	Seeks the filehandle to the new C<$offset>, similarly to perl's
		424	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		425	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		426	C<IO::AIO::SEEK_END>).
		427
		428	The resulting absolute offset will be passed to the callback, or C<-1> in
		429	case of an error.
		430
		431	In theory, the C<$whence> constants could be different than the
		432	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		433	so don't panic.
		434
		435	As a GNU/Linux (and maybe Solaris) extension, also the constants
		436	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		437	could be found. No guarantees about suitability for use in C<aio_seek> or
		438	Perl's C<sysseek> can be made though, although I would naively assume they
		439	"just work".
389		440
390	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	441	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
391		442
392	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	443	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
393		444
…		…
426		477
427	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	478	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
428	reading at byte offset C<$in_offset>, and starts writing at the current	479	reading at byte offset C<$in_offset>, and starts writing at the current
429	file offset of C<$out_fh>. Because of that, it is not safe to issue more	480	file offset of C<$out_fh>. Because of that, it is not safe to issue more
430	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	481	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
431	other.	482	other. The same C<$in_fh> works fine though, as this function does not
		483	move or use the file offset of C<$in_fh>.
432		484
433	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than	485	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
434	are written, and there is no way to find out how many bytes have been read	486	are written, and there is no way to find out how many more bytes have been
435	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of	487	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
436	bytes written to C<$out_fh>. Only if the result value equals C<$length>	488	number of bytes written to C<$out_fh>. Only if the result value equals
437	one can assume that C<$length> bytes have been read.	489	C<$length> one can assume that C<$length> bytes have been read.
438		490
439	Unlike with other C<aio_> functions, it makes a lot of sense to use	491	Unlike with other C<aio_> functions, it makes a lot of sense to use
440	C<aio_sendfile> on non-blocking sockets, as long as one end (typically	492	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
441	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while	493	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
442	the socket I/O will be non-blocking. Note, however, that you can run into	494	the socket I/O will be non-blocking. Note, however, that you can run
443	a trap where C<aio_sendfile> reads some data with readahead, then fails	495	into a trap where C<aio_sendfile> reads some data with readahead, then
444	to write all data, and when the socket is ready the next time, the data	496	fails to write all data, and when the socket is ready the next time, the
445	in the cache is already lost, forcing C<aio_sendfile> to again hit the	497	data in the cache is already lost, forcing C<aio_sendfile> to again hit
446	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage	498	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
447	much better.	499	resource usage.
448		500
449	This call tries to make use of a native C<sendfile> syscall to provide	501	This call tries to make use of a native C<sendfile>-like syscall to
450	zero-copy operation. For this to work, C<$out_fh> should refer to a	502	provide zero-copy operation. For this to work, C<$out_fh> should refer to
451	socket, and C<$in_fh> should refer to an mmap'able file.	503	a socket, and C<$in_fh> should refer to an mmap'able file.
452		504
453	If a native sendfile cannot be found or it fails with C<ENOSYS>,	505	If a native sendfile cannot be found or it fails with C<ENOSYS>,
454	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	506	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
455	it will be emulated, so you can call C<aio_sendfile> on any type of	507	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
456	filehandle regardless of the limitations of the operating system.	508	type of filehandle regardless of the limitations of the operating system.
		509
		510	As native sendfile syscalls (as practically any non-POSIX interface hacked
		511	together in a hurry to improve benchmark numbers) tend to be rather buggy
		512	on many systems, this implementation tries to work around some known bugs
		513	in Linux and FreeBSD kernels (probably others, too), but that might fail,
		514	so you really really should check the return value of C<aio_sendfile> -
		515	fewer bytes than expected might have been transferred.
457		516
458		517
459	=item aio_readahead $fh,$offset,$length, $callback->($retval)	518	=item aio_readahead $fh,$offset,$length, $callback->($retval)
460		519
461	C<aio_readahead> populates the page cache with data from a file so that	520	C<aio_readahead> populates the page cache with data from a file so that
…		…
465	whole pages, so that offset is effectively rounded down to a page boundary	524	whole pages, so that offset is effectively rounded down to a page boundary
466	and bytes are read up to the next page boundary greater than or equal to	525	and bytes are read up to the next page boundary greater than or equal to
467	(off-set+length). C<aio_readahead> does not read beyond the end of the	526	(off-set+length). C<aio_readahead> does not read beyond the end of the
468	file. The current file offset of the file is left unchanged.	527	file. The current file offset of the file is left unchanged.
469		528
470	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	529	If that syscall doesn't exist (likely if your kernel isn't Linux) it will
471	emulated by simply reading the data, which would have a similar effect.	530	be emulated by simply reading the data, which would have a similar effect.
472		531
473		532
474	=item aio_stat $fh_or_path, $callback->($status)	533	=item aio_stat $fh_or_path, $callback->($status)
475		534
476	=item aio_lstat $fh, $callback->($status)	535	=item aio_lstat $fh, $callback->($status)
…		…
483	for an explanation.	542	for an explanation.
484		543
485	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	544	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
486	error when stat'ing a large file, the results will be silently truncated	545	error when stat'ing a large file, the results will be silently truncated
487	unless perl itself is compiled with large file support.	546	unless perl itself is compiled with large file support.
		547
		548	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		549	following constants and functions (if not implemented, the constants will
		550	be C<0> and the functions will either C<croak> or fall back on traditional
		551	behaviour).
		552
		553	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		554	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		555	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
488		556
489	Example: Print the length of F</etc/passwd>:	557	Example: Print the length of F</etc/passwd>:
490		558
491	aio_stat "/etc/passwd", sub {	559	aio_stat "/etc/passwd", sub {
492	$_[0] and die "stat failed: $!";	560	$_[0] and die "stat failed: $!";
…		…
536	namemax => 255,	604	namemax => 255,
537	frsize => 1024,	605	frsize => 1024,
538	fsid => 1810	606	fsid => 1810
539	}	607	}
540		608
		609	Here is a (likely partial - send me updates!) list of fsid values used by
		610	Linux - it is safe to hardcode these when C<$^O> is C<linux>:
		611
		612	0x0000adf5 adfs
		613	0x0000adff affs
		614	0x5346414f afs
		615	0x09041934 anon-inode filesystem
		616	0x00000187 autofs
		617	0x42465331 befs
		618	0x1badface bfs
		619	0x42494e4d binfmt_misc
		620	0x9123683e btrfs
		621	0x0027e0eb cgroupfs
		622	0xff534d42 cifs
		623	0x73757245 coda
		624	0x012ff7b7 coh
		625	0x28cd3d45 cramfs
		626	0x453dcd28 cramfs-wend (wrong endianness)
		627	0x64626720 debugfs
		628	0x00001373 devfs
		629	0x00001cd1 devpts
		630	0x0000f15f ecryptfs
		631	0x00414a53 efs
		632	0x0000137d ext
		633	0x0000ef53 ext2/ext3/ext4
		634	0x0000ef51 ext2
		635	0xf2f52010 f2fs
		636	0x00004006 fat
		637	0x65735546 fuseblk
		638	0x65735543 fusectl
		639	0x0bad1dea futexfs
		640	0x01161970 gfs2
		641	0x47504653 gpfs
		642	0x00004244 hfs
		643	0xf995e849 hpfs
		644	0x00c0ffee hostfs
		645	0x958458f6 hugetlbfs
		646	0x2bad1dea inotifyfs
		647	0x00009660 isofs
		648	0x000072b6 jffs2
		649	0x3153464a jfs
		650	0x6b414653 k-afs
		651	0x0bd00bd0 lustre
		652	0x0000137f minix
		653	0x0000138f minix 30 char names
		654	0x00002468 minix v2
		655	0x00002478 minix v2 30 char names
		656	0x00004d5a minix v3
		657	0x19800202 mqueue
		658	0x00004d44 msdos
		659	0x0000564c novell
		660	0x00006969 nfs
		661	0x6e667364 nfsd
		662	0x00003434 nilfs
		663	0x5346544e ntfs
		664	0x00009fa1 openprom
		665	0x7461636F ocfs2
		666	0x00009fa0 proc
		667	0x6165676c pstorefs
		668	0x0000002f qnx4
		669	0x68191122 qnx6
		670	0x858458f6 ramfs
		671	0x52654973 reiserfs
		672	0x00007275 romfs
		673	0x67596969 rpc_pipefs
		674	0x73636673 securityfs
		675	0xf97cff8c selinux
		676	0x0000517b smb
		677	0x534f434b sockfs
		678	0x73717368 squashfs
		679	0x62656572 sysfs
		680	0x012ff7b6 sysv2
		681	0x012ff7b5 sysv4
		682	0x01021994 tmpfs
		683	0x15013346 udf
		684	0x00011954 ufs
		685	0x54190100 ufs byteswapped
		686	0x00009fa2 usbdevfs
		687	0x01021997 v9fs
		688	0xa501fcf5 vxfs
		689	0xabba1974 xenfs
		690	0x012ff7b4 xenix
		691	0x58465342 xfs
		692	0x012fd16d xia
541		693
542	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	694	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
543		695
544	Works like perl's C<utime> function (including the special case of $atime	696	Works like perl's C<utime> function (including the special case of $atime
545	and $mtime being undef). Fractional times are supported if the underlying	697	and $mtime being undef). Fractional times are supported if the underlying
…		…
573	=item aio_truncate $fh_or_path, $offset, $callback->($status)	725	=item aio_truncate $fh_or_path, $offset, $callback->($status)
574		726
575	Works like truncate(2) or ftruncate(2).	727	Works like truncate(2) or ftruncate(2).
576		728
577		729
		730	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		731
		732	Allocates or frees disk space according to the C<$mode> argument. See the
		733	linux C<fallocate> documentation for details.
		734
		735	C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
		736	space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \| IO::AIO::FALLOC_FL_KEEP_SIZE>,
		737	to deallocate a file range.
		738
		739	IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
		740	(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
		741	your L<fallocate(2)> manpage).
		742
		743	The file system block size used by C<fallocate> is presumably the
		744	C<f_bsize> returned by C<statvfs>.
		745
		746	If C<fallocate> isn't available or cannot be emulated (currently no
		747	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		748
		749
578	=item aio_chmod $fh_or_path, $mode, $callback->($status)	750	=item aio_chmod $fh_or_path, $mode, $callback->($status)
579		751
580	Works like perl's C<chmod> function.	752	Works like perl's C<chmod> function.
581		753
582		754
…		…
584		756
585	Asynchronously unlink (delete) a file and call the callback with the	757	Asynchronously unlink (delete) a file and call the callback with the
586	result code.	758	result code.
587		759
588		760
589	=item aio_mknod $path, $mode, $dev, $callback->($status)	761	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
590		762
591	[EXPERIMENTAL]	763	[EXPERIMENTAL]
592		764
593	Asynchronously create a device node (or fifo). See mknod(2).	765	Asynchronously create a device node (or fifo). See mknod(2).
594		766
595	The only (POSIX-) portable way of calling this function is:	767	The only (POSIX-) portable way of calling this function is:
596		768
597	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	769	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
598		770
		771	See C<aio_stat> for info about some potentially helpful extra constants
		772	and functions.
599		773
600	=item aio_link $srcpath, $dstpath, $callback->($status)	774	=item aio_link $srcpath, $dstpath, $callback->($status)
601		775
602	Asynchronously create a new link to the existing object at C<$srcpath> at	776	Asynchronously create a new link to the existing object at C<$srcpath> at
603	the path C<$dstpath> and call the callback with the result code.	777	the path C<$dstpath> and call the callback with the result code.
…		…
607		781
608	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	782	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
609	the path C<$dstpath> and call the callback with the result code.	783	the path C<$dstpath> and call the callback with the result code.
610		784
611		785
612	=item aio_readlink $path, $callback->($link)	786	=item aio_readlink $pathname, $callback->($link)
613		787
614	Asynchronously read the symlink specified by C<$path> and pass it to	788	Asynchronously read the symlink specified by C<$path> and pass it to
615	the callback. If an error occurs, nothing or undef gets passed to the	789	the callback. If an error occurs, nothing or undef gets passed to the
616	callback.	790	callback.
617		791
618		792
		793	=item aio_realpath $pathname, $callback->($path)
		794
		795	Asynchronously make the path absolute and resolve any symlinks in
		796	C<$path>. The resulting path only consists of directories (same as
		797	L<Cwd::realpath>).
		798
		799	This request can be used to get the absolute path of the current working
		800	directory by passing it a path of F<.> (a single dot).
		801
		802
619	=item aio_rename $srcpath, $dstpath, $callback->($status)	803	=item aio_rename $srcpath, $dstpath, $callback->($status)
620		804
621	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	805	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
622	rename(2) and call the callback with the result code.	806	rename(2) and call the callback with the result code.
		807
		808	On systems that support the AIO::WD working directory abstraction
		809	natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
		810	of failing, C<rename> is called on the absolute path of C<$wd>.
623		811
624		812
625	=item aio_mkdir $pathname, $mode, $callback->($status)	813	=item aio_mkdir $pathname, $mode, $callback->($status)
626		814
627	Asynchronously mkdir (create) a directory and call the callback with	815	Asynchronously mkdir (create) a directory and call the callback with
…		…
632	=item aio_rmdir $pathname, $callback->($status)	820	=item aio_rmdir $pathname, $callback->($status)
633		821
634	Asynchronously rmdir (delete) a directory and call the callback with the	822	Asynchronously rmdir (delete) a directory and call the callback with the
635	result code.	823	result code.
636		824
		825	On systems that support the AIO::WD working directory abstraction
		826	natively, the case C<[$wd, "."]> is specialcased - instead of failing,
		827	C<rmdir> is called on the absolute path of C<$wd>.
		828
637		829
638	=item aio_readdir $pathname, $callback->($entries)	830	=item aio_readdir $pathname, $callback->($entries)
639		831
640	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	832	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
641	directory (i.e. opendir + readdir + closedir). The entries will not be	833	directory (i.e. opendir + readdir + closedir). The entries will not be
…		…
645	array-ref with the filenames.	837	array-ref with the filenames.
646		838
647		839
648	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	840	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
649		841
650	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	842	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
651	behaviour and output format. In case of an error, C<$entries> will be	843	tune behaviour and output format. In case of an error, C<$entries> will be
652	C<undef>.	844	C<undef>.
653		845
654	The flags are a combination of the following constants, ORed together (the	846	The flags are a combination of the following constants, ORed together (the
655	flags will also be passed to the callback, possibly modified):	847	flags will also be passed to the callback, possibly modified):
656		848
657	=over 4	849	=over 4
658		850
659	=item IO::AIO::READDIR_DENTS	851	=item IO::AIO::READDIR_DENTS
660		852
661	When this flag is off, then the callback gets an arrayref with of names	853	When this flag is off, then the callback gets an arrayref consisting of
662	only (as with C<aio_readdir>), otherwise it gets an arrayref with	854	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
663	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	855	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
664	entry in more detail.	856	entry in more detail.
665		857
666	C<$name> is the name of the entry.	858	C<$name> is the name of the entry.
667		859
…		…
680	systems that do not deliver the inode information.	872	systems that do not deliver the inode information.
681		873
682	=item IO::AIO::READDIR_DIRS_FIRST	874	=item IO::AIO::READDIR_DIRS_FIRST
683		875
684	When this flag is set, then the names will be returned in an order where	876	When this flag is set, then the names will be returned in an order where
685	likely directories come first. This is useful when you need to quickly	877	likely directories come first, in optimal stat order. This is useful when
686	find directories, or you want to find all directories while avoiding to	878	you need to quickly find directories, or you want to find all directories
687	stat() each entry.	879	while avoiding to stat() each entry.
688		880
689	If the system returns type information in readdir, then this is used	881	If the system returns type information in readdir, then this is used
690	to find directories directly. Otherwise, likely directories are files	882	to find directories directly. Otherwise, likely directories are names
691	beginning with ".", or otherwise files with no dots, of which files with	883	beginning with ".", or otherwise names with no dots, of which names with
692	short names are tried first.	884	short names are tried first.
693		885
694	=item IO::AIO::READDIR_STAT_ORDER	886	=item IO::AIO::READDIR_STAT_ORDER
695		887
696	When this flag is set, then the names will be returned in an order	888	When this flag is set, then the names will be returned in an order
…		…
703		895
704	=item IO::AIO::READDIR_FOUND_UNKNOWN	896	=item IO::AIO::READDIR_FOUND_UNKNOWN
705		897
706	This flag should not be set when calling C<aio_readdirx>. Instead, it	898	This flag should not be set when calling C<aio_readdirx>. Instead, it
707	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	899	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
708	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	900	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
709	C<$type>'s are known, which can be used to speed up some algorithms.	901	C<$type>'s are known, which can be used to speed up some algorithms.
710		902
711	=back	903	=back
712		904
713		905
714	=item aio_load $path, $data, $callback->($status)	906	=item aio_load $pathname, $data, $callback->($status)
715		907
716	This is a composite request that tries to fully load the given file into	908	This is a composite request that tries to fully load the given file into
717	memory. Status is the same as with aio_read.	909	memory. Status is the same as with aio_read.
718		910
719	=cut	911	=cut
…		…
841	if ($_[0] && $! == EXDEV) {	1033	if ($_[0] && $! == EXDEV) {
842	aioreq_pri $pri;	1034	aioreq_pri $pri;
843	add $grp aio_copy $src, $dst, sub {	1035	add $grp aio_copy $src, $dst, sub {
844	$grp->result ($_[0]);	1036	$grp->result ($_[0]);
845		1037
846	if (!$_[0]) {	1038	unless ($_[0]) {
847	aioreq_pri $pri;	1039	aioreq_pri $pri;
848	add $grp aio_unlink $src;	1040	add $grp aio_unlink $src;
849	}	1041	}
850	};	1042	};
851	} else {	1043	} else {
…		…
854	};	1046	};
855		1047
856	$grp	1048	$grp
857	}	1049	}
858		1050
859	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1051	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
860		1052
861	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1053	Scans a directory (similar to C<aio_readdir>) but additionally tries to
862	efficiently separate the entries of directory C<$path> into two sets of	1054	efficiently separate the entries of directory C<$path> into two sets of
863	names, directories you can recurse into (directories), and ones you cannot	1055	names, directories you can recurse into (directories), and ones you cannot
864	recurse into (everything else, including symlinks to directories).	1056	recurse into (everything else, including symlinks to directories).
…		…
895	Then entries will be sorted into likely directories a non-initial dot	1087	Then entries will be sorted into likely directories a non-initial dot
896	currently) and likely non-directories (see C<aio_readdirx>). Then every	1088	currently) and likely non-directories (see C<aio_readdirx>). Then every
897	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1089	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
898	in order of their inode numbers. If that succeeds, it assumes that the	1090	in order of their inode numbers. If that succeeds, it assumes that the
899	entry is a directory or a symlink to directory (which will be checked	1091	entry is a directory or a symlink to directory (which will be checked
900	seperately). This is often faster than stat'ing the entry itself because	1092	separately). This is often faster than stat'ing the entry itself because
901	filesystems might detect the type of the entry without reading the inode	1093	filesystems might detect the type of the entry without reading the inode
902	data (e.g. ext2fs filetype feature), even on systems that cannot return	1094	data (e.g. ext2fs filetype feature), even on systems that cannot return
903	the filetype information on readdir.	1095	the filetype information on readdir.
904		1096
905	If the known number of directories (link count - 2) has been reached, the	1097	If the known number of directories (link count - 2) has been reached, the
…		…
921		1113
922	my $grp = aio_group $cb;	1114	my $grp = aio_group $cb;
923		1115
924	$maxreq = 4 if $maxreq <= 0;	1116	$maxreq = 4 if $maxreq <= 0;
925		1117
926	# stat once	1118	# get a wd object
927	aioreq_pri $pri;	1119	aioreq_pri $pri;
928	add $grp aio_stat $path, sub {	1120	add $grp aio_wd $path, sub {
		1121	$_[0]
929	return $grp->result () if $_[0];	1122	or return $grp->result ();
930	my $now = time;
931	my $hash1 = join ":", (stat _)[0,1,3,7,9];
932		1123
933	# read the directory entries	1124	my $wd = [shift, "."];
		1125
		1126	# stat once
934	aioreq_pri $pri;	1127	aioreq_pri $pri;
935	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1128	add $grp aio_stat $wd, sub {
936	my $entries = shift
937	or return $grp->result ();	1129	return $grp->result () if $_[0];
		1130	my $now = time;
		1131	my $hash1 = join ":", (stat _)[0,1,3,7,9];
938		1132
939	# stat the dir another time	1133	# read the directory entries
940	aioreq_pri $pri;	1134	aioreq_pri $pri;
		1135	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		1136	my $entries = shift
		1137	or return $grp->result ();
		1138
		1139	# stat the dir another time
		1140	aioreq_pri $pri;
941	add $grp aio_stat $path, sub {	1141	add $grp aio_stat $wd, sub {
942	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1142	my $hash2 = join ":", (stat _)[0,1,3,7,9];
943		1143
944	my $ndirs;	1144	my $ndirs;
945		1145
946	# take the slow route if anything looks fishy	1146	# take the slow route if anything looks fishy
947	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1147	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
948	$ndirs = -1;	1148	$ndirs = -1;
949	} else {	1149	} else {
950	# if nlink == 2, we are finished	1150	# if nlink == 2, we are finished
951	# for non-posix-fs's, we rely on nlink < 2	1151	# for non-posix-fs's, we rely on nlink < 2
952	$ndirs = (stat _)[3] - 2	1152	$ndirs = (stat _)[3] - 2
953	or return $grp->result ([], $entries);	1153	or return $grp->result ([], $entries);
954	}	1154	}
955		1155
956	my (@dirs, @nondirs);	1156	my (@dirs, @nondirs);
957		1157
958	my $statgrp = add $grp aio_group sub {	1158	my $statgrp = add $grp aio_group sub {
959	$grp->result (\@dirs, \@nondirs);	1159	$grp->result (\@dirs, \@nondirs);
960	};	1160	};
961		1161
962	limit $statgrp $maxreq;	1162	limit $statgrp $maxreq;
963	feed $statgrp sub {	1163	feed $statgrp sub {
964	return unless @$entries;	1164	return unless @$entries;
965	my $entry = shift @$entries;	1165	my $entry = shift @$entries;
966		1166
967	aioreq_pri $pri;	1167	aioreq_pri $pri;
		1168	$wd->[1] = "$entry/.";
968	add $statgrp aio_stat "$path/$entry/.", sub {	1169	add $statgrp aio_stat $wd, sub {
969	if ($_[0] < 0) {	1170	if ($_[0] < 0) {
970	push @nondirs, $entry;	1171	push @nondirs, $entry;
971	} else {	1172	} else {
972	# need to check for real directory	1173	# need to check for real directory
973	aioreq_pri $pri;	1174	aioreq_pri $pri;
		1175	$wd->[1] = $entry;
974	add $statgrp aio_lstat "$path/$entry", sub {	1176	add $statgrp aio_lstat $wd, sub {
975	if (-d _) {	1177	if (-d _) {
976	push @dirs, $entry;	1178	push @dirs, $entry;
977		1179
978	unless (--$ndirs) {	1180	unless (--$ndirs) {
979	push @nondirs, @$entries;	1181	push @nondirs, @$entries;
980	feed $statgrp;	1182	feed $statgrp;
		1183	}
		1184	} else {
		1185	push @nondirs, $entry;
981	}	1186	}
982	} else {
983	push @nondirs, $entry;
984	}	1187	}
985	}	1188	}
986	}	1189	};
987	};	1190	};
988	};	1191	};
989	};	1192	};
990	};	1193	};
991	};	1194	};
992		1195
993	$grp	1196	$grp
994	}	1197	}
995		1198
996	=item aio_rmtree $path, $callback->($status)	1199	=item aio_rmtree $pathname, $callback->($status)
997		1200
998	Delete a directory tree starting (and including) C<$path>, return the	1201	Delete a directory tree starting (and including) C<$path>, return the
999	status of the final C<rmdir> only. This is a composite request that	1202	status of the final C<rmdir> only. This is a composite request that
1000	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1203	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1001	everything else.	1204	everything else.
1002		1205
1003	=cut	1206	=cut
1004		1207
…		…
1026	};	1229	};
1027		1230
1028	$grp	1231	$grp
1029	}	1232	}
1030		1233
		1234	=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
		1235
		1236	=item aio_ioctl $fh, $request, $buf, $callback->($status)
		1237
		1238	These work just like the C<fcntl> and C<ioctl> built-in functions, except
		1239	they execute asynchronously and pass the return value to the callback.
		1240
		1241	Both calls can be used for a lot of things, some of which make more sense
		1242	to run asynchronously in their own thread, while some others make less
		1243	sense. For example, calls that block waiting for external events, such
		1244	as locking, will also lock down an I/O thread while it is waiting, which
		1245	can deadlock the whole I/O system. At the same time, there might be no
		1246	alternative to using a thread to wait.
		1247
		1248	So in general, you should only use these calls for things that do
		1249	(filesystem) I/O, not for things that wait for other events (network,
		1250	other processes), although if you are careful and know what you are doing,
		1251	you still can.
		1252
1031	=item aio_sync $callback->($status)	1253	=item aio_sync $callback->($status)
1032		1254
1033	Asynchronously call sync and call the callback when finished.	1255	Asynchronously call sync and call the callback when finished.
1034		1256
1035	=item aio_fsync $fh, $callback->($status)	1257	=item aio_fsync $fh, $callback->($status)
…		…
1042	Asynchronously call fdatasync on the given filehandle and call the	1264	Asynchronously call fdatasync on the given filehandle and call the
1043	callback with the fdatasync result code.	1265	callback with the fdatasync result code.
1044		1266
1045	If this call isn't available because your OS lacks it or it couldn't be	1267	If this call isn't available because your OS lacks it or it couldn't be
1046	detected, it will be emulated by calling C<fsync> instead.	1268	detected, it will be emulated by calling C<fsync> instead.
		1269
		1270	=item aio_syncfs $fh, $callback->($status)
		1271
		1272	Asynchronously call the syncfs syscall to sync the filesystem associated
		1273	to the given filehandle and call the callback with the syncfs result
		1274	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1275	errno to C<ENOSYS> nevertheless.
1047		1276
1048	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1277	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1049		1278
1050	Sync the data portion of the file specified by C<$offset> and C<$length>	1279	Sync the data portion of the file specified by C<$offset> and C<$length>
1051	to disk (but NOT the metadata), by calling the Linux-specific	1280	to disk (but NOT the metadata), by calling the Linux-specific
…		…
1055	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1284	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1056	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1285	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1057	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1286	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1058	manpage for details.	1287	manpage for details.
1059		1288
1060	=item aio_pathsync $path, $callback->($status)	1289	=item aio_pathsync $pathname, $callback->($status)
1061		1290
1062	This request tries to open, fsync and close the given path. This is a	1291	This request tries to open, fsync and close the given path. This is a
1063	composite request intended to sync directories after directory operations	1292	composite request intended to sync directories after directory operations
1064	(E.g. rename). This might not work on all operating systems or have any	1293	(E.g. rename). This might not work on all operating systems or have any
1065	specific effect, but usually it makes sure that directory changes get	1294	specific effect, but usually it makes sure that directory changes get
…		…
1117		1346
1118	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1347	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1119	scalars.	1348	scalars.
1120		1349
1121	It touches (reads or writes) all memory pages in the specified	1350	It touches (reads or writes) all memory pages in the specified
1122	range inside the scalar. All caveats and parameters are the same	1351	range inside the scalar. All caveats and parameters are the same
1123	as for C<aio_msync>, above, except for flags, which must be either	1352	as for C<aio_msync>, above, except for flags, which must be either
1124	C<0> (which reads all pages and ensures they are instantiated) or	1353	C<0> (which reads all pages and ensures they are instantiated) or
1125	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1354	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1126	writing an octet from it, which dirties the page).	1355	writing an octet from it, which dirties the page).
1127		1356
1128	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1357	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1129		1358
1130	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1359	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1161	documented under L<MISCELLANEOUS FUNCTIONS>.	1390	documented under L<MISCELLANEOUS FUNCTIONS>.
1162		1391
1163	Example: asynchronously lock all current and future pages into memory.	1392	Example: asynchronously lock all current and future pages into memory.
1164		1393
1165	aio_mlockall IO::AIO::MCL_FUTURE;	1394	aio_mlockall IO::AIO::MCL_FUTURE;
		1395
		1396	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1397
		1398	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1399	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1400	the ioctl is not available on your OS, then this request will fail with
		1401	C<ENOSYS>.
		1402
		1403	C<$start> is the starting offset to query extents for, C<$length> is the
		1404	size of the range to query - if it is C<undef>, then the whole file will
		1405	be queried.
		1406
		1407	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1408	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1409	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1410	the data portion.
		1411
		1412	C<$count> is the maximum number of extent records to return. If it is
		1413	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1414	case, if it is C<0>, then the callback receives the number of extents
		1415	instead of the extents themselves (which is unreliable, see below).
		1416
		1417	If an error occurs, the callback receives no arguments. The special
		1418	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1419
		1420	Otherwise, the callback receives an array reference with extent
		1421	structures. Each extent structure is an array reference itself, with the
		1422	following members:
		1423
		1424	[$logical, $physical, $length, $flags]
		1425
		1426	Flags is any combination of the following flag values (typically either C<0>
		1427	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1428
		1429	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1430	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1431	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1432	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1433	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1434	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1435
		1436	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1437	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1438	it to return all extents of a range for files with large number of
		1439	extents. The code works around all these issues if C<$count> is undef.
1166		1440
1167	=item aio_group $callback->(...)	1441	=item aio_group $callback->(...)
1168		1442
1169	This is a very special aio request: Instead of doing something, it is a	1443	This is a very special aio request: Instead of doing something, it is a
1170	container for other aio requests, which is useful if you want to bundle	1444	container for other aio requests, which is useful if you want to bundle
…		…
1207	like sleep and file handle readable/writable, the overhead this creates is	1481	like sleep and file handle readable/writable, the overhead this creates is
1208	immense (it blocks a thread for a long time) so do not use this function	1482	immense (it blocks a thread for a long time) so do not use this function
1209	except to put your application under artificial I/O pressure.	1483	except to put your application under artificial I/O pressure.
1210		1484
1211	=back	1485	=back
		1486
		1487
		1488	=head2 IO::AIO::WD - multiple working directories
		1489
		1490	Your process only has one current working directory, which is used by all
		1491	threads. This makes it hard to use relative paths (some other component
		1492	could call C<chdir> at any time, and it is hard to control when the path
		1493	will be used by IO::AIO).
		1494
		1495	One solution for this is to always use absolute paths. This usually works,
		1496	but can be quite slow (the kernel has to walk the whole path on every
		1497	access), and can also be a hassle to implement.
		1498
		1499	Newer POSIX systems have a number of functions (openat, fdopendir,
		1500	futimensat and so on) that make it possible to specify working directories
		1501	per operation.
		1502
		1503	For portability, and because the clowns who "designed", or shall I write,
		1504	perpetrated this new interface were obviously half-drunk, this abstraction
		1505	cannot be perfect, though.
		1506
		1507	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1508	object. This object stores the canonicalised, absolute version of the
		1509	path, and on systems that allow it, also a directory file descriptor.
		1510
		1511	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1512	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1513	object and a pathname instead (or the IO::AIO::WD object alone, which
		1514	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1515	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1516	to that IO::AIO::WD object.
		1517
		1518	For example, to get a wd object for F</etc> and then stat F<passwd>
		1519	inside, you would write:
		1520
		1521	aio_wd "/etc", sub {
		1522	my $etcdir = shift;
		1523
		1524	# although $etcdir can be undef on error, there is generally no reason
		1525	# to check for errors here, as aio_stat will fail with ENOENT
		1526	# when $etcdir is undef.
		1527
		1528	aio_stat [$etcdir, "passwd"], sub {
		1529	# yay
		1530	};
		1531	};
		1532
		1533	The fact that C<aio_wd> is a request and not a normal function shows that
		1534	creating an IO::AIO::WD object is itself a potentially blocking operation,
		1535	which is why it is done asynchronously.
		1536
		1537	To stat the directory obtained with C<aio_wd> above, one could write
		1538	either of the following three request calls:
		1539
		1540	aio_lstat "/etc" , sub { ... # pathname as normal string
		1541	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1542	aio_lstat $wd , sub { ... # shorthand for the previous
		1543
		1544	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1545	object and the pathname string, so you could write the following without
		1546	causing any issues due to C<$path> getting reused:
		1547
		1548	my $path = [$wd, undef];
		1549
		1550	for my $name (qw(abc def ghi)) {
		1551	$path->[1] = $name;
		1552	aio_stat $path, sub {
		1553	# ...
		1554	};
		1555	}
		1556
		1557	There are some caveats: when directories get renamed (or deleted), the
		1558	pathname string doesn't change, so will point to the new directory (or
		1559	nowhere at all), while the directory fd, if available on the system,
		1560	will still point to the original directory. Most functions accepting a
		1561	pathname will use the directory fd on newer systems, and the string on
		1562	older systems. Some functions (such as realpath) will always rely on the
		1563	string form of the pathname.
		1564
		1565	So this functionality is mainly useful to get some protection against
		1566	C<chdir>, to easily get an absolute path out of a relative path for future
		1567	reference, and to speed up doing many operations in the same directory
		1568	(e.g. when stat'ing all files in a directory).
		1569
		1570	The following functions implement this working directory abstraction:
		1571
		1572	=over 4
		1573
		1574	=item aio_wd $pathname, $callback->($wd)
		1575
		1576	Asynchonously canonicalise the given pathname and convert it to an
		1577	IO::AIO::WD object representing it. If possible and supported on the
		1578	system, also open a directory fd to speed up pathname resolution relative
		1579	to this working directory.
		1580
		1581	If something goes wrong, then C<undef> is passwd to the callback instead
		1582	of a working directory object and C<$!> is set appropriately. Since
		1583	passing C<undef> as working directory component of a pathname fails the
		1584	request with C<ENOENT>, there is often no need for error checking in the
		1585	C<aio_wd> callback, as future requests using the value will fail in the
		1586	expected way.
		1587
		1588	=item IO::AIO::CWD
		1589
		1590	This is a compiletime constant (object) that represents the process
		1591	current working directory.
		1592
		1593	Specifying this object as working directory object for a pathname is as if
		1594	the pathname would be specified directly, without a directory object. For
		1595	example, these calls are functionally identical:
		1596
		1597	aio_stat "somefile", sub { ... };
		1598	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1599
		1600	=back
		1601
		1602	To recover the path associated with an IO::AIO::WD object, you can use
		1603	C<aio_realpath>:
		1604
		1605	aio_realpath $wd, sub {
		1606	warn "path is $_[0]\n";
		1607	};
		1608
		1609	Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
		1610	sometimes, fall back to using an absolue path.
1212		1611
1213	=head2 IO::AIO::REQ CLASS	1612	=head2 IO::AIO::REQ CLASS
1214		1613
1215	All non-aggregate C<aio_*> functions return an object of this class when	1614	All non-aggregate C<aio_*> functions return an object of this class when
1216	called in non-void context.	1615	called in non-void context.
…		…
1334		1733
1335	Sets a feeder/generator on this group: every group can have an attached	1734	Sets a feeder/generator on this group: every group can have an attached
1336	generator that generates requests if idle. The idea behind this is that,	1735	generator that generates requests if idle. The idea behind this is that,
1337	although you could just queue as many requests as you want in a group,	1736	although you could just queue as many requests as you want in a group,
1338	this might starve other requests for a potentially long time. For example,	1737	this might starve other requests for a potentially long time. For example,
1339	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1738	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1340	delaying any later requests for a long time.	1739	requests, delaying any later requests for a long time.
1341		1740
1342	To avoid this, and allow incremental generation of requests, you can	1741	To avoid this, and allow incremental generation of requests, you can
1343	instead a group and set a feeder on it that generates those requests. The	1742	instead a group and set a feeder on it that generates those requests. The
1344	feed callback will be called whenever there are few enough (see C<limit>,	1743	feed callback will be called whenever there are few enough (see C<limit>,
1345	below) requests active in the group itself and is expected to queue more	1744	below) requests active in the group itself and is expected to queue more
…		…
1394		1793
1395	See C<poll_cb> for an example.	1794	See C<poll_cb> for an example.
1396		1795
1397	=item IO::AIO::poll_cb	1796	=item IO::AIO::poll_cb
1398		1797
1399	Process some outstanding events on the result pipe. You have to call this	1798	Process some requests that have reached the result phase (i.e. they have
1400	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1799	been executed but the results are not yet reported). You have to call
1401	returned earlier for whatever reason. Returns immediately when no events	1800	this "regularly" to finish outstanding requests.
1402	are outstanding. The amount of events processed depends on the settings of
1403	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1404		1801
		1802	Returns C<0> if all events could be processed (or there were no
		1803	events to process), or C<-1> if it returned earlier for whatever
		1804	reason. Returns immediately when no events are outstanding. The amount
		1805	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
		1806	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
		1807
1405	If not all requests were processed for whatever reason, the filehandle	1808	If not all requests were processed for whatever reason, the poll file
1406	will still be ready when C<poll_cb> returns, so normally you don't have to	1809	descriptor will still be ready when C<poll_cb> returns, so normally you
1407	do anything special to have it called later.	1810	don't have to do anything special to have it called later.
		1811
		1812	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1813	ready, it can be beneficial to call this function from loops which submit
		1814	a lot of requests, to make sure the results get processed when they become
		1815	available and not just when the loop is finished and the event loop takes
		1816	over again. This function returns very fast when there are no outstanding
		1817	requests.
1408		1818
1409	Example: Install an Event watcher that automatically calls	1819	Example: Install an Event watcher that automatically calls
1410	IO::AIO::poll_cb with high priority (more examples can be found in the	1820	IO::AIO::poll_cb with high priority (more examples can be found in the
1411	SYNOPSIS section, at the top of this document):	1821	SYNOPSIS section, at the top of this document):
1412		1822
…		…
1414	poll => 'r', async => 1,	1824	poll => 'r', async => 1,
1415	cb => \&IO::AIO::poll_cb);	1825	cb => \&IO::AIO::poll_cb);
1416		1826
1417	=item IO::AIO::poll_wait	1827	=item IO::AIO::poll_wait
1418		1828
1419	If there are any outstanding requests and none of them in the result	1829	Wait until either at least one request is in the result phase or no
1420	phase, wait till the result filehandle becomes ready for reading (simply	1830	requests are outstanding anymore.
1421	does a C<select> on the filehandle. This is useful if you want to	1831
1422	synchronously wait for some requests to finish).	1832	This is useful if you want to synchronously wait for some requests to
		1833	become ready, without actually handling them.
1423		1834
1424	See C<nreqs> for an example.	1835	See C<nreqs> for an example.
1425		1836
1426	=item IO::AIO::poll	1837	=item IO::AIO::poll
1427		1838
…		…
1514		1925
1515	Under normal circumstances you don't need to call this function.	1926	Under normal circumstances you don't need to call this function.
1516		1927
1517	=item IO::AIO::max_idle $nthreads	1928	=item IO::AIO::max_idle $nthreads
1518		1929
1519	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1930	Limit the number of threads (default: 4) that are allowed to idle
1520	threads that did not get a request to process within 10 seconds). That	1931	(i.e., threads that did not get a request to process within the idle
1521	means if a thread becomes idle while C<$nthreads> other threads are also	1932	timeout (default: 10 seconds). That means if a thread becomes idle while
1522	idle, it will free its resources and exit.	1933	C<$nthreads> other threads are also idle, it will free its resources and
		1934	exit.
1523		1935
1524	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1936	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1525	to allow for extremely high load situations, but want to free resources	1937	to allow for extremely high load situations, but want to free resources
1526	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1938	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1527		1939
1528	The default is probably ok in most situations, especially if thread	1940	The default is probably ok in most situations, especially if thread
1529	creation is fast. If thread creation is very slow on your system you might	1941	creation is fast. If thread creation is very slow on your system you might
1530	want to use larger values.	1942	want to use larger values.
1531		1943
		1944	=item IO::AIO::idle_timeout $seconds
		1945
		1946	Sets the minimum idle timeout (default 10) after which worker threads are
		1947	allowed to exit. SEe C<IO::AIO::max_idle>.
		1948
1532	=item IO::AIO::max_outstanding $maxreqs	1949	=item IO::AIO::max_outstanding $maxreqs
		1950
		1951	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1952	you do queue up more than this number of requests, the next call to
		1953	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1954	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1955	longer exceeded.
		1956
		1957	In other words, this setting does not enforce a queue limit, but can be
		1958	used to make poll functions block if the limit is exceeded.
1533		1959
1534	This is a very bad function to use in interactive programs because it	1960	This is a very bad function to use in interactive programs because it
1535	blocks, and a bad way to reduce concurrency because it is inexact: Better	1961	blocks, and a bad way to reduce concurrency because it is inexact: Better
1536	use an C<aio_group> together with a feed callback.	1962	use an C<aio_group> together with a feed callback.
1537		1963
1538	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1964	Its main use is in scripts without an event loop - when you want to stat
1539	do queue up more than this number of requests, the next call to the	1965	a lot of files, you can write somehting like this:
1540	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1541	function will block until the limit is no longer exceeded.
1542		1966
1543	The default value is very large, so there is no practical limit on the	1967	IO::AIO::max_outstanding 32;
1544	number of outstanding requests.
1545		1968
1546	You can still queue as many requests as you want. Therefore,	1969	for my $path (...) {
1547	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1970	aio_stat $path , ...;
1548	as a stop gap to shield against fatal memory overflow (with large values).	1971	IO::AIO::poll_cb;
		1972	}
		1973
		1974	IO::AIO::flush;
		1975
		1976	The call to C<poll_cb> inside the loop will normally return instantly, but
		1977	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1978	some requests have been handled. This keeps the loop from pushing a large
		1979	number of C<aio_stat> requests onto the queue.
		1980
		1981	The default value for C<max_outstanding> is very large, so there is no
		1982	practical limit on the number of outstanding requests.
1549		1983
1550	=back	1984	=back
1551		1985
1552	=head3 STATISTICAL INFORMATION	1986	=head3 STATISTICAL INFORMATION
1553		1987
…		…
1575		2009
1576	=back	2010	=back
1577		2011
1578	=head3 MISCELLANEOUS FUNCTIONS	2012	=head3 MISCELLANEOUS FUNCTIONS
1579		2013
1580	IO::AIO implements some functions that might be useful, but are not	2014	IO::AIO implements some functions that are useful when you want to use
1581	asynchronous.	2015	some "Advanced I/O" function not available to in Perl, without going the
		2016	"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
		2017	counterpart.
1582		2018
1583	=over 4	2019	=over 4
1584		2020
1585	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count	2021	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1586		2022
…		…
1593		2029
1594	=item IO::AIO::fadvise $fh, $offset, $len, $advice	2030	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1595		2031
1596	Simply calls the C<posix_fadvise> function (see its	2032	Simply calls the C<posix_fadvise> function (see its
1597	manpage for details). The following advice constants are	2033	manpage for details). The following advice constants are
1598	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	2034	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1599	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	2035	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1600	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2036	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1601		2037
1602	On systems that do not implement C<posix_fadvise>, this function returns	2038	On systems that do not implement C<posix_fadvise>, this function returns
1603	ENOSYS, otherwise the return value of C<posix_fadvise>.	2039	ENOSYS, otherwise the return value of C<posix_fadvise>.
1604		2040
1605	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2041	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1606		2042
1607	Simply calls the C<posix_madvise> function (see its	2043	Simply calls the C<posix_madvise> function (see its
1608	manpage for details). The following advice constants are	2044	manpage for details). The following advice constants are
1609	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2045	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1610	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2046	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1611		2047
1612	On systems that do not implement C<posix_madvise>, this function returns	2048	On systems that do not implement C<posix_madvise>, this function returns
1613	ENOSYS, otherwise the return value of C<posix_madvise>.	2049	ENOSYS, otherwise the return value of C<posix_madvise>.
1614		2050
1615	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2051	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1616		2052
1617	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2053	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1618	$scalar (see its manpage for details). The following protect	2054	$scalar (see its manpage for details). The following protect
1619	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2055	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1620	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2056	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1621		2057
1622	On systems that do not implement C<mprotect>, this function returns	2058	On systems that do not implement C<mprotect>, this function returns
1623	ENOSYS, otherwise the return value of C<mprotect>.	2059	ENOSYS, otherwise the return value of C<mprotect>.
1624		2060
1625	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2061	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1626		2062
1627	Memory-maps a file (or anonymous memory range) and attaches it to the	2063	Memory-maps a file (or anonymous memory range) and attaches it to the
1628	given C<$scalar>, which will act like a string scalar.	2064	given C<$scalar>, which will act like a string scalar. Returns true on
		2065	success, and false otherwise.
1629		2066
1630	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2067	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1631	change the string length, and most read-only operations such as copying it	2068	change the string length, and most read-only operations such as copying it
1632	or searching it with regexes and so on.	2069	or searching it with regexes and so on.
1633		2070
…		…
1644	filesize.	2081	filesize.
1645		2082
1646	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,	2083	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1647	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,	2084	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1648		2085
1649	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or	2086	C<$flags> can be a combination of
1650	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when	2087	C<IO::AIO::MAP_SHARED> or
1651	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>	2088	C<IO::AIO::MAP_PRIVATE>,
		2089	or a number of system-specific flags (when not available, the are C<0>):
1652	(which is set to C<MAP_ANON> if your system only provides this	2090	C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1653	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,	2091	C<IO::AIO::MAP_LOCKED>,
1654	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or	2092	C<IO::AIO::MAP_NORESERVE>,
		2093	C<IO::AIO::MAP_POPULATE>,
1655	C<IO::AIO::MAP_NONBLOCK>	2094	C<IO::AIO::MAP_NONBLOCK>,
		2095	C<IO::AIO::MAP_FIXED>,
		2096	C<IO::AIO::MAP_GROWSDOWN>,
		2097	C<IO::AIO::MAP_32BIT>,
		2098	C<IO::AIO::MAP_HUGETLB> or
		2099	C<IO::AIO::MAP_STACK>.
1656		2100
1657	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.	2101	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1658		2102
1659	C<$offset> is the offset from the start of the file - it generally must be	2103	C<$offset> is the offset from the start of the file - it generally must be
1660	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.	2104	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
…		…
1685		2129
1686	Calls the C<munlockall> function.	2130	Calls the C<munlockall> function.
1687		2131
1688	On systems that do not implement C<munlockall>, this function returns	2132	On systems that do not implement C<munlockall>, this function returns
1689	ENOSYS, otherwise the return value of C<munlockall>.	2133	ENOSYS, otherwise the return value of C<munlockall>.
		2134
		2135	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2136
		2137	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2138	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2139	should be the file offset.
		2140
		2141	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2142	silently corrupt the data in this case.
		2143
		2144	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2145	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2146	C<IO::AIO::SPLICE_F_GIFT>.
		2147
		2148	See the C<splice(2)> manpage for details.
		2149
		2150	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2151
		2152	Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
		2153	description for C<IO::AIO::splice> above for details.
		2154
		2155	=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
		2156
		2157	Attempts to query or change the pipe buffer size. Obviously works only
		2158	on pipes, and currently works only on GNU/Linux systems, and fails with
		2159	C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
		2160	size on other systems, drop me a note.
		2161
		2162	=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
		2163
		2164	This is a direct interface to the Linux L<pipe2(2)> system call. If
		2165	C<$flags> is missing or C<0>, then this should be the same as a call to
		2166	perl's built-in C<pipe> function and create a new pipe, and works on
		2167	systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
		2168	(..., 4096, O_BINARY)>.
		2169
		2170	If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
		2171	the given flags (Linux 2.6.27, glibc 2.9).
		2172
		2173	On success, the read and write file handles are returned.
		2174
		2175	On error, nothing will be returned. If the pipe2 syscall is missing and
		2176	C<$flags> is non-zero, fails with C<ENOSYS>.
		2177
		2178	Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
		2179	time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
		2180	C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1690		2181
1691	=back	2182	=back
1692		2183
1693	=cut	2184	=cut
1694		2185
…		…
1729	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2220	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1730	\&IO::AIO::poll_cb);	2221	\&IO::AIO::poll_cb);
1731		2222
1732	=head2 FORK BEHAVIOUR	2223	=head2 FORK BEHAVIOUR
1733		2224
1734	This module should do "the right thing" when the process using it forks:	2225	Usage of pthreads in a program changes the semantics of fork
		2226	considerably. Specifically, only async-safe functions can be called after
		2227	fork. Perl doesn't know about this, so in general, you cannot call fork
		2228	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2229	pthreads, so this applies, but many other extensions and (for inexplicable
		2230	reasons) perl itself often is linked against pthreads, so this limitation
		2231	applies to quite a lot of perls.
1735		2232
1736	Before the fork, IO::AIO enters a quiescent state where no requests	2233	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1737	can be added in other threads and no results will be processed. After	2234	only works in the process that loaded it. Forking is fully supported, but
1738	the fork the parent simply leaves the quiescent state and continues	2235	using IO::AIO in the child is not.
1739	request/result processing, while the child frees the request/result queue
1740	(so that the requests started before the fork will only be handled in the
1741	parent). Threads will be started on demand until the limit set in the
1742	parent process has been reached again.
1743		2236
1744	In short: the parent will, after a short pause, continue as if fork had	2237	You might get around by not I<using> IO::AIO before (or after)
1745	not been called, while the child will act as if IO::AIO has not been used	2238	forking. You could also try to call the L<IO::AIO::reinit> function in the
1746	yet.	2239	child:
		2240
		2241	=over 4
		2242
		2243	=item IO::AIO::reinit
		2244
		2245	Abandons all current requests and I/O threads and simply reinitialises all
		2246	data structures. This is not an operation supported by any standards, but
		2247	happens to work on GNU/Linux and some newer BSD systems.
		2248
		2249	The only reasonable use for this function is to call it after forking, if
		2250	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2251	the process will result in undefined behaviour. Calling it at any time
		2252	will also result in any undefined (by POSIX) behaviour.
		2253
		2254	=back
1747		2255
1748	=head2 MEMORY USAGE	2256	=head2 MEMORY USAGE
1749		2257
1750	Per-request usage:	2258	Per-request usage:
1751		2259

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.185 by root, Sat Dec 11 19:06:07 2010 UTC vs. Revision 1.262 by root, Thu Jun 9 03:15:37 2016 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.185 by root, Sat Dec 11 19:06:07 2010 UTC vs.
Revision 1.262 by root, Thu Jun 9 03:15:37 2016 UTC