[ViewVC] Diff of: cvs/IO-AIO/README

Comparing IO-AIO/README (file contents):
Revision 1.32 by root, Thu Oct 2 11:35:03 2008 UTC vs.
Revision 1.43 by root, Sun Jan 10 23:44:02 2010 UTC

…		…
24	$req->cancel; # cancel request if still in queue	24	$req->cancel; # cancel request if still in queue
25		25
26	my $grp = aio_group sub { print "all stats done\n" };	26	my $grp = aio_group sub { print "all stats done\n" };
27	add $grp aio_stat "..." for ...;	27	add $grp aio_stat "..." for ...;
28		28
29	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
30	use AnyEvent::AIO;
31
32	# EV integration
33	my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51
52	DESCRIPTION	29	DESCRIPTION
53	This module implements asynchronous I/O using whatever means your	30	This module implements asynchronous I/O using whatever means your
54	operating system supports.	31	operating system supports. It is implemented as an interface to "libeio"
		32	(<http://software.schmorp.de/pkg/libeio.html>).
55		33
56	Asynchronous means that operations that can normally block your program	34	Asynchronous means that operations that can normally block your program
57	(e.g. reading from disk) will be done asynchronously: the operation will	35	(e.g. reading from disk) will be done asynchronously: the operation will
58	still block, but you can do something else in the meantime. This is	36	still block, but you can do something else in the meantime. This is
59	extremely useful for programs that need to stay interactive even when	37	extremely useful for programs that need to stay interactive even when
…		…
64	operations concurrently.	42	operations concurrently.
65		43
66	While most of this works on all types of file descriptors (for example	44	While most of this works on all types of file descriptors (for example
67	sockets), using these functions on file descriptors that support	45	sockets), using these functions on file descriptors that support
68	nonblocking operation (again, sockets, pipes etc.) is very inefficient.	46	nonblocking operation (again, sockets, pipes etc.) is very inefficient.
69	Use an event loop for that (such as the Event module): IO::AIO will	47	Use an event loop for that (such as the EV module): IO::AIO will
70	naturally fit into such an event loop itself.	48	naturally fit into such an event loop itself.
71		49
72	In this version, a number of threads are started that execute your	50	In this version, a number of threads are started that execute your
73	requests and signal their completion. You don't need thread support in	51	requests and signal their completion. You don't need thread support in
74	perl, and the threads created by this module will not be visible to	52	perl, and the threads created by this module will not be visible to
…		…
83	it is currently not reentrant in any way, so use appropriate locking	61	it is currently not reentrant in any way, so use appropriate locking
84	yourself, always call "poll_cb" from within the same thread, or never	62	yourself, always call "poll_cb" from within the same thread, or never
85	call "poll_cb" (or other "aio_" functions) recursively.	63	call "poll_cb" (or other "aio_" functions) recursively.
86		64
87	EXAMPLE	65	EXAMPLE
88	This is a simple example that uses the Event module and loads	66	This is a simple example that uses the EV module and loads /etc/passwd
89	/etc/passwd asynchronously:	67	asynchronously:
90		68
91	use Fcntl;	69	use Fcntl;
92	use Event;	70	use EV;
93	use IO::AIO;	71	use IO::AIO;
94		72
95	# register the IO::AIO callback with Event	73	# register the IO::AIO callback with EV
96	Event->io (fd => IO::AIO::poll_fileno,	74	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
97	poll => 'r',
98	cb => \&IO::AIO::poll_cb);
99		75
100	# queue the request to open /etc/passwd	76	# queue the request to open /etc/passwd
101	aio_open "/etc/passwd", O_RDONLY, 0, sub {	77	aio_open "/etc/passwd", O_RDONLY, 0, sub {
102	my $fh = shift	78	my $fh = shift
103	or die "error while opening: $!";	79	or die "error while opening: $!";
…		…
115		91
116	# file contents now in $contents	92	# file contents now in $contents
117	print $contents;	93	print $contents;
118		94
119	# exit event loop and program	95	# exit event loop and program
120	Event::unloop;	96	EV::unloop;
121	};	97	};
122	};	98	};
123		99
124	# possibly queue up other requests, or open GUI windows,	100	# possibly queue up other requests, or open GUI windows,
125	# check for sockets etc. etc.	101	# check for sockets etc. etc.
126		102
127	# process events as long as there are some:	103	# process events as long as there are some:
128	Event::loop;	104	EV::loop;
129		105
130	REQUEST ANATOMY AND LIFETIME	106	REQUEST ANATOMY AND LIFETIME
131	Every "aio_*" function creates a request. which is a C data structure	107	Every "aio_*" function creates a request. which is a C data structure
132	not directly visible to Perl.	108	not directly visible to Perl.
133		109
…		…
169	anymore (except possibly for the Perl object, but its connection to	145	anymore (except possibly for the Perl object, but its connection to
170	the actual aio request is severed and calling its methods will	146	the actual aio request is severed and calling its methods will
171	either do nothing or result in a runtime error).	147	either do nothing or result in a runtime error).
172		148
173	FUNCTIONS	149	FUNCTIONS
		150	QUICK OVERVIEW
		151	This section simply lists the prototypes of the most important functions
		152	for quick reference. See the following sections for function-by-function
		153	documentation.
		154
		155	aio_open $pathname, $flags, $mode, $callback->($fh)
		156	aio_close $fh, $callback->($status)
		157	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		158	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		159	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		160	aio_readahead $fh,$offset,$length, $callback->($retval)
		161	aio_stat $fh_or_path, $callback->($status)
		162	aio_lstat $fh, $callback->($status)
		163	aio_statvfs $fh_or_path, $callback->($statvfs)
		164	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		165	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		166	aio_truncate $fh_or_path, $offset, $callback->($status)
		167	aio_chmod $fh_or_path, $mode, $callback->($status)
		168	aio_unlink $pathname, $callback->($status)
		169	aio_mknod $path, $mode, $dev, $callback->($status)
		170	aio_link $srcpath, $dstpath, $callback->($status)
		171	aio_symlink $srcpath, $dstpath, $callback->($status)
		172	aio_readlink $path, $callback->($link)
		173	aio_rename $srcpath, $dstpath, $callback->($status)
		174	aio_mkdir $pathname, $mode, $callback->($status)
		175	aio_rmdir $pathname, $callback->($status)
		176	aio_readdir $pathname, $callback->($entries)
		177	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		178	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		179	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		180	aio_load $path, $data, $callback->($status)
		181	aio_copy $srcpath, $dstpath, $callback->($status)
		182	aio_move $srcpath, $dstpath, $callback->($status)
		183	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		184	aio_rmtree $path, $callback->($status)
		185	aio_sync $callback->($status)
		186	aio_fsync $fh, $callback->($status)
		187	aio_fdatasync $fh, $callback->($status)
		188	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		189	aio_pathsync $path, $callback->($status)
		190	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		191	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		192	aio_group $callback->(...)
		193	aio_nop $callback->()
		194
		195	$prev_pri = aioreq_pri [$pri]
		196	aioreq_nice $pri_adjust
		197
		198	IO::AIO::poll_wait
		199	IO::AIO::poll_cb
		200	IO::AIO::poll
		201	IO::AIO::flush
		202	IO::AIO::max_poll_reqs $nreqs
		203	IO::AIO::max_poll_time $seconds
		204	IO::AIO::min_parallel $nthreads
		205	IO::AIO::max_parallel $nthreads
		206	IO::AIO::max_idle $nthreads
		207	IO::AIO::max_outstanding $maxreqs
		208	IO::AIO::nreqs
		209	IO::AIO::nready
		210	IO::AIO::npending
		211
		212	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		213	IO::AIO::fadvise $fh, $offset, $len, $advice
		214	IO::AIO::mlockall $flags
		215	IO::AIO::munlockall
		216
174	AIO REQUEST FUNCTIONS	217	AIO REQUEST FUNCTIONS
175	All the "aio_*" calls are more or less thin wrappers around the syscall	218	All the "aio_*" calls are more or less thin wrappers around the syscall
176	with the same name (sans "aio_"). The arguments are similar or	219	with the same name (sans "aio_"). The arguments are similar or
177	identical, and they all accept an additional (and optional) $callback	220	identical, and they all accept an additional (and optional) $callback
178	argument which must be a code reference. This code reference will get	221	argument which must be a code reference. This code reference will get
…		…
275	Or in other words: the file descriptor will be closed, but it will	318	Or in other words: the file descriptor will be closed, but it will
276	not be free for reuse until the perl filehandle is closed.	319	not be free for reuse until the perl filehandle is closed.
277		320
278	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	321	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
279	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	322	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
280	Reads or writes $length bytes from the specified $fh and $offset	323	Reads or writes $length bytes from or to the specified $fh and
281	into the scalar given by $data and offset $dataoffset and calls the	324	$offset into the scalar given by $data and offset $dataoffset and
282	callback without the actual number of bytes read (or -1 on error,	325	calls the callback without the actual number of bytes read (or -1 on
283	just like the syscall).	326	error, just like the syscall).
		327
		328	"aio_read" will, like "sysread", shrink or grow the $data scalar to
		329	offset plus the actual number of bytes read.
284		330
285	If $offset is undefined, then the current file descriptor offset	331	If $offset is undefined, then the current file descriptor offset
286	will be used (and updated), otherwise the file descriptor offset	332	will be used (and updated), otherwise the file descriptor offset
287	will not be changed by these calls.	333	will not be changed by these calls.
288		334
…		…
311	more than one "aio_sendfile" per $out_fh, as they will interfere	357	more than one "aio_sendfile" per $out_fh, as they will interfere
312	with each other.	358	with each other.
313		359
314	This call tries to make use of a native "sendfile" syscall to	360	This call tries to make use of a native "sendfile" syscall to
315	provide zero-copy operation. For this to work, $out_fh should refer	361	provide zero-copy operation. For this to work, $out_fh should refer
316	to a socket, and $in_fh should refer to mmap'able file.	362	to a socket, and $in_fh should refer to an mmap'able file.
317		363
318	If the native sendfile call fails or is not implemented, it will be	364	If a native sendfile cannot be found or it fails with "ENOSYS",
		365	"ENOTSUP", "EOPNOTSUPP", "EAFNOSUPPORT", "EPROTOTYPE" or "ENOTSOCK",
319	emulated, so you can call "aio_sendfile" on any type of filehandle	366	it will be emulated, so you can call "aio_sendfile" on any type of
320	regardless of the limitations of the operating system.	367	filehandle regardless of the limitations of the operating system.
321		368
322	Please note, however, that "aio_sendfile" can read more bytes from	369	Please note, however, that "aio_sendfile" can read more bytes from
323	$in_fh than are written, and there is no way to find out how many	370	$in_fh than are written, and there is no way to find out how many
324	bytes have been read from "aio_sendfile" alone, as "aio_sendfile"	371	bytes have been read from "aio_sendfile" alone, as "aio_sendfile"
325	only provides the number of bytes written to $out_fh. Only if the	372	only provides the number of bytes written to $out_fh. Only if the
…		…
360	aio_stat "/etc/passwd", sub {	407	aio_stat "/etc/passwd", sub {
361	$_[0] and die "stat failed: $!";	408	$_[0] and die "stat failed: $!";
362	print "size is ", -s _, "\n";	409	print "size is ", -s _, "\n";
363	};	410	};
364		411
		412	aio_statvfs $fh_or_path, $callback->($statvfs)
		413	Works like the POSIX "statvfs" or "fstatvfs" syscalls, depending on
		414	whether a file handle or path was passed.
		415
		416	On success, the callback is passed a hash reference with the
		417	following members: "bsize", "frsize", "blocks", "bfree", "bavail",
		418	"files", "ffree", "favail", "fsid", "flag" and "namemax". On
		419	failure, "undef" is passed.
		420
		421	The following POSIX IO::AIO::ST_* constants are defined: "ST_RDONLY"
		422	and "ST_NOSUID".
		423
		424	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		425	their correct value when available, or to 0 on systems that do not
		426	support them: "ST_NODEV", "ST_NOEXEC", "ST_SYNCHRONOUS",
		427	"ST_MANDLOCK", "ST_WRITE", "ST_APPEND", "ST_IMMUTABLE",
		428	"ST_NOATIME", "ST_NODIRATIME" and "ST_RELATIME".
		429
		430	Example: stat "/wd" and dump out the data if successful.
		431
		432	aio_statvfs "/wd", sub {
		433	my $f = $_[0]
		434	or die "statvfs: $!";
		435
		436	use Data::Dumper;
		437	say Dumper $f;
		438	};
		439
		440	# result:
		441	{
		442	bsize => 1024,
		443	bfree => 4333064312,
		444	blocks => 10253828096,
		445	files => 2050765568,
		446	flag => 4096,
		447	favail => 2042092649,
		448	bavail => 4333064312,
		449	ffree => 2042092649,
		450	namemax => 255,
		451	frsize => 1024,
		452	fsid => 1810
		453	}
		454
365	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	455	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
366	Works like perl's "utime" function (including the special case of	456	Works like perl's "utime" function (including the special case of
367	$atime and $mtime being undef). Fractional times are supported if	457	$atime and $mtime being undef). Fractional times are supported if
368	the underlying syscalls support them.	458	the underlying syscalls support them.
369		459
…		…
439	aio_readdir $pathname, $callback->($entries)	529	aio_readdir $pathname, $callback->($entries)
440	Unlike the POSIX call of the same name, "aio_readdir" reads an	530	Unlike the POSIX call of the same name, "aio_readdir" reads an
441	entire directory (i.e. opendir + readdir + closedir). The entries	531	entire directory (i.e. opendir + readdir + closedir). The entries
442	will not be sorted, and will NOT include the "." and ".." entries.	532	will not be sorted, and will NOT include the "." and ".." entries.
443		533
444	The callback a single argument which is either "undef" or an	534	The callback is passed a single argument which is either "undef" or
445	array-ref with the filenames.	535	an array-ref with the filenames.
		536
		537	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		538	Quite similar to "aio_readdir", but the $flags argument allows to
		539	tune behaviour and output format. In case of an error, $entries will
		540	be "undef".
		541
		542	The flags are a combination of the following constants, ORed
		543	together (the flags will also be passed to the callback, possibly
		544	modified):
		545
		546	IO::AIO::READDIR_DENTS
		547	When this flag is off, then the callback gets an arrayref with
		548	of names only (as with "aio_readdir"), otherwise it gets an
		549	arrayref with "[$name, $type, $inode]" arrayrefs, each
		550	describing a single directory entry in more detail.
		551
		552	$name is the name of the entry.
		553
		554	$type is one of the "IO::AIO::DT_xxx" constants:
		555
		556	"IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",
		557	"IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",
		558	"IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
		559
		560	"IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If
		561	you need to know, you have to run stat yourself. Also, for speed
		562	reasons, the $type scalars are read-only: you can not modify
		563	them.
		564
		565	$inode is the inode number (which might not be exact on systems
		566	with 64 bit inode numbers and 32 bit perls). This field has
		567	unspecified content on systems that do not deliver the inode
		568	information.
		569
		570	IO::AIO::READDIR_DIRS_FIRST
		571	When this flag is set, then the names will be returned in an
		572	order where likely directories come first. This is useful when
		573	you need to quickly find directories, or you want to find all
		574	directories while avoiding to stat() each entry.
		575
		576	If the system returns type information in readdir, then this is
		577	used to find directories directly. Otherwise, likely directories
		578	are files beginning with ".", or otherwise files with no dots,
		579	of which files with short names are tried first.
		580
		581	IO::AIO::READDIR_STAT_ORDER
		582	When this flag is set, then the names will be returned in an
		583	order suitable for stat()'ing each one. That is, when you plan
		584	to stat() all files in the given directory, then the returned
		585	order will likely be fastest.
		586
		587	If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
		588	specified, then the likely dirs come first, resulting in a less
		589	optimal stat order.
		590
		591	IO::AIO::READDIR_FOUND_UNKNOWN
		592	This flag should not be set when calling "aio_readdirx".
		593	Instead, it is being set by "aio_readdirx", when any of the
		594	$type's found were "IO::AIO::DT_UNKNOWN". The absense of this
		595	flag therefore indicates that all $type's are known, which can
		596	be used to speed up some algorithms.
446		597
447	aio_load $path, $data, $callback->($status)	598	aio_load $path, $data, $callback->($status)
448	This is a composite request that tries to fully load the given file	599	This is a composite request that tries to fully load the given file
449	into memory. Status is the same as with aio_read.	600	into memory. Status is the same as with aio_read.
450		601
451	aio_copy $srcpath, $dstpath, $callback->($status)	602	aio_copy $srcpath, $dstpath, $callback->($status)
452	Try to copy the file (directories not supported as either source	603	Try to copy the file (directories not supported as either source
453	or destination) from $srcpath to $dstpath and call the callback with	604	or destination) from $srcpath to $dstpath and call the callback with
454	the 0 (error) or -1 ok.	605	a status of 0 (ok) or -1 (error, see $!).
455		606
456	This is a composite request that creates the destination file with	607	This is a composite request that creates the destination file with
457	mode 0200 and copies the contents of the source file into it using	608	mode 0200 and copies the contents of the source file into it using
458	"aio_sendfile", followed by restoring atime, mtime, access mode and	609	"aio_sendfile", followed by restoring atime, mtime, access mode and
459	uid/gid, in that order.	610	uid/gid, in that order.
…		…
463	uid/gid, where errors are being ignored.	614	uid/gid, where errors are being ignored.
464		615
465	aio_move $srcpath, $dstpath, $callback->($status)	616	aio_move $srcpath, $dstpath, $callback->($status)
466	Try to move the file (directories not supported as either source	617	Try to move the file (directories not supported as either source
467	or destination) from $srcpath to $dstpath and call the callback with	618	or destination) from $srcpath to $dstpath and call the callback with
468	the 0 (error) or -1 ok.	619	a status of 0 (ok) or -1 (error, see $!).
469		620
470	This is a composite request that tries to rename(2) the file first.	621	This is a composite request that tries to rename(2) the file first;
471	If rename files with "EXDEV", it copies the file with "aio_copy"	622	if rename fails with "EXDEV", it copies the file with "aio_copy"
472	and, if that is successful, unlinking the $srcpath.	623	and, if that is successful, unlinks the $srcpath.
473		624
474	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	625	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
475	Scans a directory (similar to "aio_readdir") but additionally tries	626	Scans a directory (similar to "aio_readdir") but additionally tries
476	to efficiently separate the entries of directory $path into two sets	627	to efficiently separate the entries of directory $path into two sets
477	of names, directories you can recurse into (directories), and ones	628	of names, directories you can recurse into (directories), and ones
…		…
497	Implementation notes.	648	Implementation notes.
498		649
499	The "aio_readdir" cannot be avoided, but "stat()"'ing every entry	650	The "aio_readdir" cannot be avoided, but "stat()"'ing every entry
500	can.	651	can.
501		652
		653	If readdir returns file type information, then this is used directly
		654	to find directories.
		655
502	After reading the directory, the modification time, size etc. of the	656	Otherwise, after reading the directory, the modification time, size
503	directory before and after the readdir is checked, and if they match	657	etc. of the directory before and after the readdir is checked, and
504	(and isn't the current time), the link count will be used to decide	658	if they match (and isn't the current time), the link count will be
505	how many entries are directories (if >= 2). Otherwise, no knowledge	659	used to decide how many entries are directories (if >= 2).
506	of the number of subdirectories will be assumed.	660	Otherwise, no knowledge of the number of subdirectories will be
		661	assumed.
507		662
508	Then entries will be sorted into likely directories (everything	663	Then entries will be sorted into likely directories a non-initial
509	without a non-initial dot currently) and likely non-directories	664	dot currently) and likely non-directories (see "aio_readdirx"). Then
510	(everything else). Then every entry plus an appended "/." will be	665	every entry plus an appended "/." will be "stat"'ed, likely
511	"stat"'ed, likely directories first. If that succeeds, it assumes	666	directories first, in order of their inode numbers. If that
512	that the entry is a directory or a symlink to directory (which will	667	succeeds, it assumes that the entry is a directory or a symlink to
513	be checked seperately). This is often faster than stat'ing the entry	668	directory (which will be checked seperately). This is often faster
514	itself because filesystems might detect the type of the entry	669	than stat'ing the entry itself because filesystems might detect the
515	without reading the inode data (e.g. ext2fs filetype feature).	670	type of the entry without reading the inode data (e.g. ext2fs
		671	filetype feature), even on systems that cannot return the filetype
		672	information on readdir.
516		673
517	If the known number of directories (link count - 2) has been	674	If the known number of directories (link count - 2) has been
518	reached, the rest of the entries is assumed to be non-directories.	675	reached, the rest of the entries is assumed to be non-directories.
519		676
520	This only works with certainty on POSIX (= UNIX) filesystems, which	677	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
541	Asynchronously call fdatasync on the given filehandle and call the	698	Asynchronously call fdatasync on the given filehandle and call the
542	callback with the fdatasync result code.	699	callback with the fdatasync result code.
543		700
544	If this call isn't available because your OS lacks it or it couldn't	701	If this call isn't available because your OS lacks it or it couldn't
545	be detected, it will be emulated by calling "fsync" instead.	702	be detected, it will be emulated by calling "fsync" instead.
		703
		704	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		705	Sync the data portion of the file specified by $offset and $length
		706	to disk (but NOT the metadata), by calling the Linux-specific
		707	sync_file_range call. If sync_file_range is not available or it
		708	returns ENOSYS, then fdatasync or fsync is being substituted.
		709
		710	$flags can be a combination of
		711	"IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE",
		712	"IO::AIO::SYNC_FILE_RANGE_WRITE" and
		713	"IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range
		714	manpage for details.
546		715
547	aio_pathsync $path, $callback->($status)	716	aio_pathsync $path, $callback->($status)
548	This request tries to open, fsync and close the given path. This is	717	This request tries to open, fsync and close the given path. This is
549	a composite request intended to sync directories after directory	718	a composite request intended to sync directories after directory
550	operations (E.g. rename). This might not work on all operating	719	operations (E.g. rename). This might not work on all operating
551	systems or have any specific effect, but usually it makes sure that	720	systems or have any specific effect, but usually it makes sure that
552	directory changes get written to disc. It works for anything that	721	directory changes get written to disc. It works for anything that
553	can be opened for read-only, not just directories.	722	can be opened for read-only, not just directories.
554		723
		724	Future versions of this function might fall back to other methods
		725	when "fsync" on the directory fails (such as calling "sync").
		726
555	Passes 0 when everything went ok, and -1 on error.	727	Passes 0 when everything went ok, and -1 on error.
		728
		729	aio_msync $scalar, $offset = 0, $length = undef, flags = 0,
		730	$callback->($status)
		731	This is a rather advanced IO::AIO call, which only works on
		732	mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
		733	also works on data scalars managed by the Sys::Mmap or Mmap modules,
		734	note that the scalar must only be modified in-place while an aio
		735	operation is pending on it).
		736
		737	It calls the "msync" function of your OS, if available, with the
		738	memory area starting at $offset in the string and ending $length
		739	bytes later. If $length is negative, counts from the end, and if
		740	$length is "undef", then it goes till the end of the string. The
		741	flags can be a combination of "IO::AIO::MS_ASYNC",
		742	"IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC".
		743
		744	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
		745	$callback->($status)
		746	This is a rather advanced IO::AIO call, which works best on
		747	mmap(2)ed scalars.
		748
		749	It touches (reads or writes) all memory pages in the specified range
		750	inside the scalar. All caveats and parameters are the same as for
		751	"aio_msync", above, except for flags, which must be either 0 (which
		752	reads all pages and ensures they are instantiated) or
		753	"IO::AIO::MT_MODIFY", which modifies the memory page s(by reading
		754	and writing an octet from it, which dirties the page).
556		755
557	aio_group $callback->(...)	756	aio_group $callback->(...)
558	This is a very special aio request: Instead of doing something, it	757	This is a very special aio request: Instead of doing something, it
559	is a container for other aio requests, which is useful if you want	758	is a container for other aio requests, which is useful if you want
560	to bundle many requests into a single, composite, request with a	759	to bundle many requests into a single, composite, request with a
…		…
603		802
604	cancel $req	803	cancel $req
605	Cancels the request, if possible. Has the effect of skipping	804	Cancels the request, if possible. Has the effect of skipping
606	execution when entering the execute state and skipping calling the	805	execution when entering the execute state and skipping calling the
607	callback when entering the the result state, but will leave the	806	callback when entering the the result state, but will leave the
608	request otherwise untouched. That means that requests that currently	807	request otherwise untouched (with the exception of readdir). That
609	execute will not be stopped and resources held by the request will	808	means that requests that currently execute will not be stopped and
610	not be freed prematurely.	809	resources held by the request will not be freed prematurely.
611		810
612	cb $req $callback->(...)	811	cb $req $callback->(...)
613	Replace (or simply set) the callback registered to the request.	812	Replace (or simply set) the callback registered to the request.
614		813
615	IO::AIO::GRP CLASS	814	IO::AIO::GRP CLASS
…		…
676		875
677	$grp->cancel_subs	876	$grp->cancel_subs
678	Cancel all subrequests and clears any feeder, but not the group	877	Cancel all subrequests and clears any feeder, but not the group
679	request itself. Useful when you queued a lot of events but got a	878	request itself. Useful when you queued a lot of events but got a
680	result early.	879	result early.
		880
		881	The group request will finish normally (you cannot add requests to
		882	the group).
681		883
682	$grp->result (...)	884	$grp->result (...)
683	Set the result value(s) that will be passed to the group callback	885	Set the result value(s) that will be passed to the group callback
684	when all subrequests have finished and set the groups errno to the	886	when all subrequests have finished and set the groups errno to the
685	current value of errno (just like calling "errno" without an error	887	current value of errno (just like calling "errno" without an error
…		…
715	does not impose any limits).	917	does not impose any limits).
716		918
717	If the feed does not queue more requests when called, it will be	919	If the feed does not queue more requests when called, it will be
718	automatically removed from the group.	920	automatically removed from the group.
719		921
720	If the feed limit is 0, it will be set to 2 automatically.	922	If the feed limit is 0 when this method is called, it will be set to
		923	2 automatically.
721		924
722	Example:	925	Example:
723		926
724	# stat all files in @files, but only ever use four aio requests concurrently:	927	# stat all files in @files, but only ever use four aio requests concurrently:
725		928
…		…
736	Sets the feeder limit for the group: The feeder will be called	939	Sets the feeder limit for the group: The feeder will be called
737	whenever the group contains less than this many requests.	940	whenever the group contains less than this many requests.
738		941
739	Setting the limit to 0 will pause the feeding process.	942	Setting the limit to 0 will pause the feeding process.
740		943
		944	The default value for the limit is 0, but note that setting a feeder
		945	automatically bumps it up to 2.
		946
741	SUPPORT FUNCTIONS	947	SUPPORT FUNCTIONS
742	EVENT PROCESSING AND EVENT LOOP INTEGRATION	948	EVENT PROCESSING AND EVENT LOOP INTEGRATION
743	$fileno = IO::AIO::poll_fileno	949	$fileno = IO::AIO::poll_fileno
744	Return the request result pipe file descriptor. This filehandle	950	Return the request result pipe file descriptor. This filehandle
745	must be polled for reading by some mechanism outside this module	951	must be polled for reading by some mechanism outside this module
746	(e.g. Event or select, see below or the SYNOPSIS). If the pipe	952	(e.g. EV, Glib, select and so on, see below or the SYNOPSIS). If the
747	becomes readable you have to call "poll_cb" to check the results.	953	pipe becomes readable you have to call "poll_cb" to check the
		954	results.
748		955
749	See "poll_cb" for an example.	956	See "poll_cb" for an example.
750		957
751	IO::AIO::poll_cb	958	IO::AIO::poll_cb
752	Process some outstanding events on the result pipe. You have to call	959	Process some outstanding events on the result pipe. You have to call
…		…
759	If not all requests were processed for whatever reason, the	966	If not all requests were processed for whatever reason, the
760	filehandle will still be ready when "poll_cb" returns, so normally	967	filehandle will still be ready when "poll_cb" returns, so normally
761	you don't have to do anything special to have it called later.	968	you don't have to do anything special to have it called later.
762		969
763	Example: Install an Event watcher that automatically calls	970	Example: Install an Event watcher that automatically calls
764	IO::AIO::poll_cb with high priority:	971	IO::AIO::poll_cb with high priority (more examples can be found in
		972	the SYNOPSIS section, at the top of this document):
765		973
766	Event->io (fd => IO::AIO::poll_fileno,	974	Event->io (fd => IO::AIO::poll_fileno,
767	poll => 'r', async => 1,	975	poll => 'r', async => 1,
768	cb => \&IO::AIO::poll_cb);	976	cb => \&IO::AIO::poll_cb);
		977
		978	IO::AIO::poll_wait
		979	If there are any outstanding requests and none of them in the result
		980	phase, wait till the result filehandle becomes ready for reading
		981	(simply does a "select" on the filehandle. This is useful if you
		982	want to synchronously wait for some requests to finish).
		983
		984	See "nreqs" for an example.
		985
		986	IO::AIO::poll
		987	Waits until some requests have been handled.
		988
		989	Returns the number of requests processed, but is otherwise strictly
		990	equivalent to:
		991
		992	IO::AIO::poll_wait, IO::AIO::poll_cb
		993
		994	IO::AIO::flush
		995	Wait till all outstanding AIO requests have been handled.
		996
		997	Strictly equivalent to:
		998
		999	IO::AIO::poll_wait, IO::AIO::poll_cb
		1000	while IO::AIO::nreqs;
769		1001
770	IO::AIO::max_poll_reqs $nreqs	1002	IO::AIO::max_poll_reqs $nreqs
771	IO::AIO::max_poll_time $seconds	1003	IO::AIO::max_poll_time $seconds
772	These set the maximum number of requests (default 0, meaning	1004	These set the maximum number of requests (default 0, meaning
773	infinity) that are being processed by "IO::AIO::poll_cb" in one	1005	infinity) that are being processed by "IO::AIO::poll_cb" in one
…		…
797	# use a low priority so other tasks have priority	1029	# use a low priority so other tasks have priority
798	Event->io (fd => IO::AIO::poll_fileno,	1030	Event->io (fd => IO::AIO::poll_fileno,
799	poll => 'r', nice => 1,	1031	poll => 'r', nice => 1,
800	cb => &IO::AIO::poll_cb);	1032	cb => &IO::AIO::poll_cb);
801		1033
802	IO::AIO::poll_wait
803	If there are any outstanding requests and none of them in the result
804	phase, wait till the result filehandle becomes ready for reading
805	(simply does a "select" on the filehandle. This is useful if you
806	want to synchronously wait for some requests to finish).
807
808	See "nreqs" for an example.
809
810	IO::AIO::poll
811	Waits until some requests have been handled.
812
813	Returns the number of requests processed, but is otherwise strictly
814	equivalent to:
815
816	IO::AIO::poll_wait, IO::AIO::poll_cb
817
818	IO::AIO::flush
819	Wait till all outstanding AIO requests have been handled.
820
821	Strictly equivalent to:
822
823	IO::AIO::poll_wait, IO::AIO::poll_cb
824	while IO::AIO::nreqs;
825
826	CONTROLLING THE NUMBER OF THREADS	1034	CONTROLLING THE NUMBER OF THREADS
827	IO::AIO::min_parallel $nthreads	1035	IO::AIO::min_parallel $nthreads
828	Set the minimum number of AIO threads to $nthreads. The current	1036	Set the minimum number of AIO threads to $nthreads. The current
829	default is 8, which means eight asynchronous operations can execute	1037	default is 8, which means eight asynchronous operations can execute
830	concurrently at any one time (the number of outstanding requests,	1038	concurrently at any one time (the number of outstanding requests,
…		…
908	executed).	1116	executed).
909		1117
910	IO::AIO::npending	1118	IO::AIO::npending
911	Returns the number of requests currently in the pending state	1119	Returns the number of requests currently in the pending state
912	(executed, but not yet processed by poll_cb).	1120	(executed, but not yet processed by poll_cb).
		1121
		1122	MISCELLANEOUS FUNCTIONS
		1123	IO::AIO implements some functions that might be useful, but are not
		1124	asynchronous.
		1125
		1126	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1127	Calls the "eio_sendfile_sync" function, which is like
		1128	"aio_sendfile", but is blocking (this makes most sense if you know
		1129	the input data is likely cached already and the output filehandle is
		1130	set to non-blocking operations).
		1131
		1132	Returns the number of bytes copied, or -1 on error.
		1133
		1134	IO::AIO::fadvise $fh, $offset, $len, $advice
		1135	Simply calls the "posix_fadvise" function (see it's manpage for
		1136	details). The following advice constants are avaiable:
		1137	"IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL",
		1138	"IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE",
		1139	"IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED".
		1140
		1141	On systems that do not implement "posix_fadvise", this function
		1142	returns ENOSYS, otherwise the return value of "posix_fadvise".
		1143
		1144	IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1145	Memory-maps a file (or anonymous memory range) and attaches it to
		1146	the given $scalar, which will act like a string scalar.
		1147
		1148	The only operations allowed on the scalar are "substr"/"vec" that
		1149	don't change the string length, and most read-only operations such
		1150	as copying it or searching it with regexes and so on.
		1151
		1152	Anything else is unsafe and will, at best, result in memory leaks.
		1153
		1154	The memory map associated with the $scalar is automatically removed
		1155	when the $scalar is destroyed, or when the "IO::AIO::mmap" or
		1156	"IO::AIO::munmap" functions are called.
		1157
		1158	This calls the "mmap"(2) function internally. See your system's
		1159	manual page for details on the $length, $prot and $flags parameters.
		1160
		1161	The $length must be larger than zero and smaller than the actual
		1162	filesize.
		1163
		1164	$prot is a combination of "IO::AIO::PROT_NONE",
		1165	"IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
		1166	"IO::AIO::PROT_WRITE",
		1167
		1168	$flags can be a combination of "IO::AIO::MAP_SHARED" or
		1169	"IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
		1170	not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS"
		1171	(which is set to "MAP_ANON" if your system only provides this
		1172	constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",
		1173	"IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or
		1174	"IO::AIO::MAP_NONBLOCK"
		1175
		1176	If $fh is "undef", then a file descriptor of -1 is passed.
		1177
		1178	$offset is the offset from the start of the file - it generally must
		1179	be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
		1180
		1181	Example:
		1182
		1183	use Digest::MD5;
		1184	use IO::AIO;
		1185
		1186	open my $fh, "<verybigfile"
		1187	or die "$!";
		1188
		1189	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1190	or die "verybigfile: $!";
		1191
		1192	my $fast_md5 = md5 $data;
		1193
		1194	IO::AIO::munmap $scalar
		1195	Removes a previous mmap and undefines the $scalar.
		1196
		1197	IO::AIO::mlockall $flags
		1198	Calls the "mlockall" function with the given $flags (a combination
		1199	of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL__FUTURE").
		1200
		1201	On systems that do not implement "mlockall", this function returns
		1202	ENOSYS, otherwise the return value of "mlockall".
		1203
		1204	IO::AIO::munlockall
		1205	Calls the "munlockall" function.
		1206
		1207	On systems that do not implement "munlockall", this function returns
		1208	ENOSYS, otherwise the return value of "munlockall".
		1209
		1210	EVENT LOOP INTEGRATION
		1211	It is recommended to use AnyEvent::AIO to integrate IO::AIO
		1212	automatically into many event loops:
		1213
		1214	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1215	use AnyEvent::AIO;
		1216
		1217	You can also integrate IO::AIO manually into many event loops, here are
		1218	some examples of how to do this:
		1219
		1220	# EV integration
		1221	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1222
		1223	# Event integration
		1224	Event->io (fd => IO::AIO::poll_fileno,
		1225	poll => 'r',
		1226	cb => \&IO::AIO::poll_cb);
		1227
		1228	# Glib/Gtk2 integration
		1229	add_watch Glib::IO IO::AIO::poll_fileno,
		1230	in => sub { IO::AIO::poll_cb; 1 };
		1231
		1232	# Tk integration
		1233	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1234	readable => \&IO::AIO::poll_cb);
		1235
		1236	# Danga::Socket integration
		1237	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1238	\&IO::AIO::poll_cb);
913		1239
914	FORK BEHAVIOUR	1240	FORK BEHAVIOUR
915	This module should do "the right thing" when the process using it forks:	1241	This module should do "the right thing" when the process using it forks:
916		1242
917	Before the fork, IO::AIO enters a quiescent state where no requests can	1243	Before the fork, IO::AIO enters a quiescent state where no requests can

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Comparing IO-AIO/README (file contents): Revision 1.32 by root, Thu Oct 2 11:35:03 2008 UTC vs. Revision 1.43 by root, Sun Jan 10 23:44:02 2010 UTC

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Comparing IO-AIO/README (file contents):
Revision 1.32 by root, Thu Oct 2 11:35:03 2008 UTC vs.
Revision 1.43 by root, Sun Jan 10 23:44:02 2010 UTC