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Revision 1.136 by root, Tue Sep 30 14:07:59 2008 UTC vs.
Revision 1.186 by root, Thu Dec 30 07:19:31 2010 UTC

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4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub { 9 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10 my $fh = shift 10 my $fh = shift
11 or die "/etc/passwd: $!"; 11 or die "/etc/passwd: $!";
12 ... 12 ...
13 }; 13 };
14 14
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26 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
27 27
28 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
29 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
30 30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37 # Event integration
38 Event->io (fd => IO::AIO::poll_fileno,
39 poll => 'r',
40 cb => \&IO::AIO::poll_cb);
41
42 # Glib/Gtk2 integration
43 add_watch Glib::IO IO::AIO::poll_fileno,
44 in => sub { IO::AIO::poll_cb; 1 };
45
46 # Tk integration
47 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48 readable => \&IO::AIO::poll_cb);
49
50 # Danga::Socket integration
51 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52 \&IO::AIO::poll_cb);
53
54=head1 DESCRIPTION 31=head1 DESCRIPTION
55 32
56This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
57operating system supports. 34operating system supports. It is implemented as an interface to C<libeio>
35(L<http://software.schmorp.de/pkg/libeio.html>).
58 36
59Asynchronous means that operations that can normally block your program 37Asynchronous means that operations that can normally block your program
60(e.g. reading from disk) will be done asynchronously: the operation 38(e.g. reading from disk) will be done asynchronously: the operation
61will still block, but you can do something else in the meantime. This 39will still block, but you can do something else in the meantime. This
62is extremely useful for programs that need to stay interactive even 40is extremely useful for programs that need to stay interactive even
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66on a RAID volume or over NFS when you do a number of stat operations 44on a RAID volume or over NFS when you do a number of stat operations
67concurrently. 45concurrently.
68 46
69While most of this works on all types of file descriptors (for 47While most of this works on all types of file descriptors (for
70example sockets), using these functions on file descriptors that 48example sockets), using these functions on file descriptors that
71support nonblocking operation (again, sockets, pipes etc.) is very 49support nonblocking operation (again, sockets, pipes etc.) is
72inefficient. Use an event loop for that (such as the L<Event|Event> 50very inefficient. Use an event loop for that (such as the L<EV>
73module): IO::AIO will naturally fit into such an event loop itself. 51module): IO::AIO will naturally fit into such an event loop itself.
74 52
75In this version, a number of threads are started that execute your 53In this version, a number of threads are started that execute your
76requests and signal their completion. You don't need thread support 54requests and signal their completion. You don't need thread support
77in perl, and the threads created by this module will not be visible 55in perl, and the threads created by this module will not be visible
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87yourself, always call C<poll_cb> from within the same thread, or never 65yourself, always call C<poll_cb> from within the same thread, or never
88call C<poll_cb> (or other C<aio_> functions) recursively. 66call C<poll_cb> (or other C<aio_> functions) recursively.
89 67
90=head2 EXAMPLE 68=head2 EXAMPLE
91 69
92This is a simple example that uses the Event module and loads 70This is a simple example that uses the EV module and loads
93F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
94 72
95 use Fcntl; 73 use Fcntl;
96 use Event; 74 use EV;
97 use IO::AIO; 75 use IO::AIO;
98 76
99 # register the IO::AIO callback with Event 77 # register the IO::AIO callback with EV
100 Event->io (fd => IO::AIO::poll_fileno, 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
101 poll => 'r',
102 cb => \&IO::AIO::poll_cb);
103 79
104 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
105 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
106 my $fh = shift 82 my $fh = shift
107 or die "error while opening: $!"; 83 or die "error while opening: $!";
108 84
109 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
110 my $size = -s $fh; 86 my $size = -s $fh;
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119 95
120 # file contents now in $contents 96 # file contents now in $contents
121 print $contents; 97 print $contents;
122 98
123 # exit event loop and program 99 # exit event loop and program
124 Event::unloop; 100 EV::unloop;
125 }; 101 };
126 }; 102 };
127 103
128 # possibly queue up other requests, or open GUI windows, 104 # possibly queue up other requests, or open GUI windows,
129 # check for sockets etc. etc. 105 # check for sockets etc. etc.
130 106
131 # process events as long as there are some: 107 # process events as long as there are some:
132 Event::loop; 108 EV::loop;
133 109
134=head1 REQUEST ANATOMY AND LIFETIME 110=head1 REQUEST ANATOMY AND LIFETIME
135 111
136Every C<aio_*> function creates a request. which is a C data structure not 112Every C<aio_*> function creates a request. which is a C data structure not
137directly visible to Perl. 113directly visible to Perl.
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187 163
188package IO::AIO; 164package IO::AIO;
189 165
190use Carp (); 166use Carp ();
191 167
192no warnings; 168use common::sense;
193use strict 'vars';
194 169
195use base 'Exporter'; 170use base 'Exporter';
196 171
197BEGIN { 172BEGIN {
198 our $VERSION = '3.1'; 173 our $VERSION = '3.71';
199 174
200 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
201 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
202 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
203 aio_fdatasync aio_pathsync aio_readahead 178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
204 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
205 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
206 aio_chmod aio_utime aio_truncate); 181 aio_chmod aio_utime aio_truncate
182 aio_msync aio_mtouch aio_mlock aio_mlockall
183 aio_statvfs);
207 184
208 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 185 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
209 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 186 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
210 min_parallel max_parallel max_idle 187 min_parallel max_parallel max_idle
211 nreqs nready npending nthreads 188 nreqs nready npending nthreads
212 max_poll_time max_poll_reqs); 189 max_poll_time max_poll_reqs
190 sendfile fadvise madvise
191 mmap munmap munlock munlockall);
192
193 push @AIO_REQ, qw(aio_busy); # not exported
213 194
214 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 195 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
215 196
216 require XSLoader; 197 require XSLoader;
217 XSLoader::load ("IO::AIO", $VERSION); 198 XSLoader::load ("IO::AIO", $VERSION);
218} 199}
219 200
220=head1 FUNCTIONS 201=head1 FUNCTIONS
202
203=head2 QUICK OVERVIEW
204
205This section simply lists the prototypes of the most important functions
206for quick reference. See the following sections for function-by-function
207documentation.
208
209 aio_open $pathname, $flags, $mode, $callback->($fh)
210 aio_close $fh, $callback->($status)
211 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214 aio_readahead $fh,$offset,$length, $callback->($retval)
215 aio_stat $fh_or_path, $callback->($status)
216 aio_lstat $fh, $callback->($status)
217 aio_statvfs $fh_or_path, $callback->($statvfs)
218 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
220 aio_truncate $fh_or_path, $offset, $callback->($status)
221 aio_chmod $fh_or_path, $mode, $callback->($status)
222 aio_unlink $pathname, $callback->($status)
223 aio_mknod $path, $mode, $dev, $callback->($status)
224 aio_link $srcpath, $dstpath, $callback->($status)
225 aio_symlink $srcpath, $dstpath, $callback->($status)
226 aio_readlink $path, $callback->($link)
227 aio_rename $srcpath, $dstpath, $callback->($status)
228 aio_mkdir $pathname, $mode, $callback->($status)
229 aio_rmdir $pathname, $callback->($status)
230 aio_readdir $pathname, $callback->($entries)
231 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
234 aio_load $path, $data, $callback->($status)
235 aio_copy $srcpath, $dstpath, $callback->($status)
236 aio_move $srcpath, $dstpath, $callback->($status)
237 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238 aio_rmtree $path, $callback->($status)
239 aio_sync $callback->($status)
240 aio_fsync $fh, $callback->($status)
241 aio_fdatasync $fh, $callback->($status)
242 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243 aio_pathsync $path, $callback->($status)
244 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247 aio_mlockall $flags, $callback->($status)
248 aio_group $callback->(...)
249 aio_nop $callback->()
250
251 $prev_pri = aioreq_pri [$pri]
252 aioreq_nice $pri_adjust
253
254 IO::AIO::poll_wait
255 IO::AIO::poll_cb
256 IO::AIO::poll
257 IO::AIO::flush
258 IO::AIO::max_poll_reqs $nreqs
259 IO::AIO::max_poll_time $seconds
260 IO::AIO::min_parallel $nthreads
261 IO::AIO::max_parallel $nthreads
262 IO::AIO::max_idle $nthreads
263 IO::AIO::max_outstanding $maxreqs
264 IO::AIO::nreqs
265 IO::AIO::nready
266 IO::AIO::npending
267
268 IO::AIO::sendfile $ofh, $ifh, $offset, $count
269 IO::AIO::fadvise $fh, $offset, $len, $advice
270 IO::AIO::madvise $scalar, $offset, $length, $advice
271 IO::AIO::mprotect $scalar, $offset, $length, $protect
272 IO::AIO::munlock $scalar, $offset = 0, $length = undef
273 IO::AIO::munlockall
221 274
222=head2 AIO REQUEST FUNCTIONS 275=head2 AIO REQUEST FUNCTIONS
223 276
224All the C<aio_*> calls are more or less thin wrappers around the syscall 277All the C<aio_*> calls are more or less thin wrappers around the syscall
225with the same name (sans C<aio_>). The arguments are similar or identical, 278with the same name (sans C<aio_>). The arguments are similar or identical,
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305by the umask in effect then the request is being executed, so better never 358by the umask in effect then the request is being executed, so better never
306change the umask. 359change the umask.
307 360
308Example: 361Example:
309 362
310 aio_open "/etc/passwd", O_RDONLY, 0, sub { 363 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
311 if ($_[0]) { 364 if ($_[0]) {
312 print "open successful, fh is $_[0]\n"; 365 print "open successful, fh is $_[0]\n";
313 ... 366 ...
314 } else { 367 } else {
315 die "open failed: $!\n"; 368 die "open failed: $!\n";
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336 389
337=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 390=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
338 391
339=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 392=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
340 393
341Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 394Reads or writes C<$length> bytes from or to the specified C<$fh> and
342into the scalar given by C<$data> and offset C<$dataoffset> and calls the 395C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
343callback without the actual number of bytes read (or -1 on error, just 396and calls the callback without the actual number of bytes read (or -1 on
344like the syscall). 397error, just like the syscall).
398
399C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
400offset plus the actual number of bytes read.
345 401
346If C<$offset> is undefined, then the current file descriptor offset will 402If C<$offset> is undefined, then the current file descriptor offset will
347be used (and updated), otherwise the file descriptor offset will not be 403be used (and updated), otherwise the file descriptor offset will not be
348changed by these calls. 404changed by these calls.
349 405
350If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 406If C<$length> is undefined in C<aio_write>, use the remaining length of
407C<$data>.
351 408
352If C<$dataoffset> is less than zero, it will be counted from the end of 409If C<$dataoffset> is less than zero, it will be counted from the end of
353C<$data>. 410C<$data>.
354 411
355The C<$data> scalar I<MUST NOT> be modified in any way while the request 412The C<$data> scalar I<MUST NOT> be modified in any way while the request
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371reading at byte offset C<$in_offset>, and starts writing at the current 428reading at byte offset C<$in_offset>, and starts writing at the current
372file offset of C<$out_fh>. Because of that, it is not safe to issue more 429file offset of C<$out_fh>. Because of that, it is not safe to issue more
373than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 430than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
374other. 431other.
375 432
433Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
434are written, and there is no way to find out how many bytes have been read
435from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
436bytes written to C<$out_fh>. Only if the result value equals C<$length>
437one can assume that C<$length> bytes have been read.
438
439Unlike with other C<aio_> functions, it makes a lot of sense to use
440C<aio_sendfile> on non-blocking sockets, as long as one end (typically
441the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
442the socket I/O will be non-blocking. Note, however, that you can run into
443a trap where C<aio_sendfile> reads some data with readahead, then fails
444to write all data, and when the socket is ready the next time, the data
445in the cache is already lost, forcing C<aio_sendfile> to again hit the
446disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
447much better.
448
376This call tries to make use of a native C<sendfile> syscall to provide 449This call tries to make use of a native C<sendfile> syscall to provide
377zero-copy operation. For this to work, C<$out_fh> should refer to a 450zero-copy operation. For this to work, C<$out_fh> should refer to a
378socket, and C<$in_fh> should refer to mmap'able file. 451socket, and C<$in_fh> should refer to an mmap'able file.
379 452
380If the native sendfile call fails or is not implemented, it will be 453If a native sendfile cannot be found or it fails with C<ENOSYS>,
454C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
381emulated, so you can call C<aio_sendfile> on any type of filehandle 455it will be emulated, so you can call C<aio_sendfile> on any type of
382regardless of the limitations of the operating system. 456filehandle regardless of the limitations of the operating system.
383
384Please note, however, that C<aio_sendfile> can read more bytes from
385C<$in_fh> than are written, and there is no way to find out how many
386bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
387provides the number of bytes written to C<$out_fh>. Only if the result
388value equals C<$length> one can assume that C<$length> bytes have been
389read.
390 457
391 458
392=item aio_readahead $fh,$offset,$length, $callback->($retval) 459=item aio_readahead $fh,$offset,$length, $callback->($retval)
393 460
394C<aio_readahead> populates the page cache with data from a file so that 461C<aio_readahead> populates the page cache with data from a file so that
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425 $_[0] and die "stat failed: $!"; 492 $_[0] and die "stat failed: $!";
426 print "size is ", -s _, "\n"; 493 print "size is ", -s _, "\n";
427 }; 494 };
428 495
429 496
497=item aio_statvfs $fh_or_path, $callback->($statvfs)
498
499Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
500whether a file handle or path was passed.
501
502On success, the callback is passed a hash reference with the following
503members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
504C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
505is passed.
506
507The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
508C<ST_NOSUID>.
509
510The following non-POSIX IO::AIO::ST_* flag masks are defined to
511their correct value when available, or to C<0> on systems that do
512not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
513C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
514C<ST_NODIRATIME> and C<ST_RELATIME>.
515
516Example: stat C</wd> and dump out the data if successful.
517
518 aio_statvfs "/wd", sub {
519 my $f = $_[0]
520 or die "statvfs: $!";
521
522 use Data::Dumper;
523 say Dumper $f;
524 };
525
526 # result:
527 {
528 bsize => 1024,
529 bfree => 4333064312,
530 blocks => 10253828096,
531 files => 2050765568,
532 flag => 4096,
533 favail => 2042092649,
534 bavail => 4333064312,
535 ffree => 2042092649,
536 namemax => 255,
537 frsize => 1024,
538 fsid => 1810
539 }
540
541
430=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 542=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
431 543
432Works like perl's C<utime> function (including the special case of $atime 544Works like perl's C<utime> function (including the special case of $atime
433and $mtime being undef). Fractional times are supported if the underlying 545and $mtime being undef). Fractional times are supported if the underlying
434syscalls support them. 546syscalls support them.
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527 639
528Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 640Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
529directory (i.e. opendir + readdir + closedir). The entries will not be 641directory (i.e. opendir + readdir + closedir). The entries will not be
530sorted, and will B<NOT> include the C<.> and C<..> entries. 642sorted, and will B<NOT> include the C<.> and C<..> entries.
531 643
532The callback a single argument which is either C<undef> or an array-ref 644The callback is passed a single argument which is either C<undef> or an
533with the filenames. 645array-ref with the filenames.
646
647
648=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
649
650Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
651behaviour and output format. In case of an error, C<$entries> will be
652C<undef>.
653
654The flags are a combination of the following constants, ORed together (the
655flags will also be passed to the callback, possibly modified):
656
657=over 4
658
659=item IO::AIO::READDIR_DENTS
660
661When this flag is off, then the callback gets an arrayref with of names
662only (as with C<aio_readdir>), otherwise it gets an arrayref with
663C<[$name, $type, $inode]> arrayrefs, each describing a single directory
664entry in more detail.
665
666C<$name> is the name of the entry.
667
668C<$type> is one of the C<IO::AIO::DT_xxx> constants:
669
670C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
671C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
672C<IO::AIO::DT_WHT>.
673
674C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
675know, you have to run stat yourself. Also, for speed reasons, the C<$type>
676scalars are read-only: you can not modify them.
677
678C<$inode> is the inode number (which might not be exact on systems with 64
679bit inode numbers and 32 bit perls). This field has unspecified content on
680systems that do not deliver the inode information.
681
682=item IO::AIO::READDIR_DIRS_FIRST
683
684When this flag is set, then the names will be returned in an order where
685likely directories come first. This is useful when you need to quickly
686find directories, or you want to find all directories while avoiding to
687stat() each entry.
688
689If the system returns type information in readdir, then this is used
690to find directories directly. Otherwise, likely directories are files
691beginning with ".", or otherwise files with no dots, of which files with
692short names are tried first.
693
694=item IO::AIO::READDIR_STAT_ORDER
695
696When this flag is set, then the names will be returned in an order
697suitable for stat()'ing each one. That is, when you plan to stat()
698all files in the given directory, then the returned order will likely
699be fastest.
700
701If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
702the likely dirs come first, resulting in a less optimal stat order.
703
704=item IO::AIO::READDIR_FOUND_UNKNOWN
705
706This flag should not be set when calling C<aio_readdirx>. Instead, it
707is being set by C<aio_readdirx>, when any of the C<$type>'s found were
708C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
709C<$type>'s are known, which can be used to speed up some algorithms.
710
711=back
534 712
535 713
536=item aio_load $path, $data, $callback->($status) 714=item aio_load $path, $data, $callback->($status)
537 715
538This is a composite request that tries to fully load the given file into 716This is a composite request that tries to fully load the given file into
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563 741
564=item aio_copy $srcpath, $dstpath, $callback->($status) 742=item aio_copy $srcpath, $dstpath, $callback->($status)
565 743
566Try to copy the I<file> (directories not supported as either source or 744Try to copy the I<file> (directories not supported as either source or
567destination) from C<$srcpath> to C<$dstpath> and call the callback with 745destination) from C<$srcpath> to C<$dstpath> and call the callback with
568the C<0> (error) or C<-1> ok. 746a status of C<0> (ok) or C<-1> (error, see C<$!>).
569 747
570This is a composite request that creates the destination file with 748This is a composite request that creates the destination file with
571mode 0200 and copies the contents of the source file into it using 749mode 0200 and copies the contents of the source file into it using
572C<aio_sendfile>, followed by restoring atime, mtime, access mode and 750C<aio_sendfile>, followed by restoring atime, mtime, access mode and
573uid/gid, in that order. 751uid/gid, in that order.
… …
585 my $grp = aio_group $cb; 763 my $grp = aio_group $cb;
586 764
587 aioreq_pri $pri; 765 aioreq_pri $pri;
588 add $grp aio_open $src, O_RDONLY, 0, sub { 766 add $grp aio_open $src, O_RDONLY, 0, sub {
589 if (my $src_fh = $_[0]) { 767 if (my $src_fh = $_[0]) {
590 my @stat = stat $src_fh; 768 my @stat = stat $src_fh; # hmm, might block over nfs?
591 769
592 aioreq_pri $pri; 770 aioreq_pri $pri;
593 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 771 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
594 if (my $dst_fh = $_[0]) { 772 if (my $dst_fh = $_[0]) {
595 aioreq_pri $pri; 773 aioreq_pri $pri;
596 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 774 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
597 if ($_[0] == $stat[7]) { 775 if ($_[0] == $stat[7]) {
598 $grp->result (0); 776 $grp->result (0);
599 close $src_fh; 777 close $src_fh;
600 778
601 # those should not normally block. should. should. 779 my $ch = sub {
602 utime $stat[8], $stat[9], $dst; 780 aioreq_pri $pri;
603 chmod $stat[2] & 07777, $dst_fh; 781 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
604 chown $stat[4], $stat[5], $dst_fh; 782 aioreq_pri $pri;
783 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
784 aioreq_pri $pri;
785 add $grp aio_close $dst_fh;
786 }
787 };
788 };
605 789
606 aioreq_pri $pri; 790 aioreq_pri $pri;
607 add $grp aio_close $dst_fh; 791 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
792 if ($_[0] < 0 && $! == ENOSYS) {
793 aioreq_pri $pri;
794 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
795 } else {
796 $ch->();
797 }
798 };
608 } else { 799 } else {
609 $grp->result (-1); 800 $grp->result (-1);
610 close $src_fh; 801 close $src_fh;
611 close $dst_fh; 802 close $dst_fh;
612 803
… …
629 820
630=item aio_move $srcpath, $dstpath, $callback->($status) 821=item aio_move $srcpath, $dstpath, $callback->($status)
631 822
632Try to move the I<file> (directories not supported as either source or 823Try to move the I<file> (directories not supported as either source or
633destination) from C<$srcpath> to C<$dstpath> and call the callback with 824destination) from C<$srcpath> to C<$dstpath> and call the callback with
634the C<0> (error) or C<-1> ok. 825a status of C<0> (ok) or C<-1> (error, see C<$!>).
635 826
636This is a composite request that tries to rename(2) the file first. If 827This is a composite request that tries to rename(2) the file first; if
637rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 828rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
638that is successful, unlinking the C<$srcpath>. 829that is successful, unlinks the C<$srcpath>.
639 830
640=cut 831=cut
641 832
642sub aio_move($$;$) { 833sub aio_move($$;$) {
643 my ($src, $dst, $cb) = @_; 834 my ($src, $dst, $cb) = @_;
… …
690 881
691Implementation notes. 882Implementation notes.
692 883
693The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 884The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
694 885
886If readdir returns file type information, then this is used directly to
887find directories.
888
695After reading the directory, the modification time, size etc. of the 889Otherwise, after reading the directory, the modification time, size etc.
696directory before and after the readdir is checked, and if they match (and 890of the directory before and after the readdir is checked, and if they
697isn't the current time), the link count will be used to decide how many 891match (and isn't the current time), the link count will be used to decide
698entries are directories (if >= 2). Otherwise, no knowledge of the number 892how many entries are directories (if >= 2). Otherwise, no knowledge of the
699of subdirectories will be assumed. 893number of subdirectories will be assumed.
700 894
701Then entries will be sorted into likely directories (everything without 895Then entries will be sorted into likely directories a non-initial dot
702a non-initial dot currently) and likely non-directories (everything 896currently) and likely non-directories (see C<aio_readdirx>). Then every
703else). Then every entry plus an appended C</.> will be C<stat>'ed, 897entry plus an appended C</.> will be C<stat>'ed, likely directories first,
704likely directories first. If that succeeds, it assumes that the entry 898in order of their inode numbers. If that succeeds, it assumes that the
705is a directory or a symlink to directory (which will be checked 899entry is a directory or a symlink to directory (which will be checked
706seperately). This is often faster than stat'ing the entry itself because 900seperately). This is often faster than stat'ing the entry itself because
707filesystems might detect the type of the entry without reading the inode 901filesystems might detect the type of the entry without reading the inode
708data (e.g. ext2fs filetype feature). 902data (e.g. ext2fs filetype feature), even on systems that cannot return
903the filetype information on readdir.
709 904
710If the known number of directories (link count - 2) has been reached, the 905If the known number of directories (link count - 2) has been reached, the
711rest of the entries is assumed to be non-directories. 906rest of the entries is assumed to be non-directories.
712 907
713This only works with certainty on POSIX (= UNIX) filesystems, which 908This only works with certainty on POSIX (= UNIX) filesystems, which
… …
735 my $now = time; 930 my $now = time;
736 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 931 my $hash1 = join ":", (stat _)[0,1,3,7,9];
737 932
738 # read the directory entries 933 # read the directory entries
739 aioreq_pri $pri; 934 aioreq_pri $pri;
740 add $grp aio_readdir $path, sub { 935 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
741 my $entries = shift 936 my $entries = shift
742 or return $grp->result (); 937 or return $grp->result ();
743 938
744 # stat the dir another time 939 # stat the dir another time
745 aioreq_pri $pri; 940 aioreq_pri $pri;
… …
751 # take the slow route if anything looks fishy 946 # take the slow route if anything looks fishy
752 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 947 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
753 $ndirs = -1; 948 $ndirs = -1;
754 } else { 949 } else {
755 # if nlink == 2, we are finished 950 # if nlink == 2, we are finished
756 # on non-posix-fs's, we rely on nlink < 2 951 # for non-posix-fs's, we rely on nlink < 2
757 $ndirs = (stat _)[3] - 2 952 $ndirs = (stat _)[3] - 2
758 or return $grp->result ([], $entries); 953 or return $grp->result ([], $entries);
759 } 954 }
760 955
761 # sort into likely dirs and likely nondirs
762 # dirs == files without ".", short entries first
763 $entries = [map $_->[0],
764 sort { $b->[1] cmp $a->[1] }
765 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
766 @$entries];
767
768 my (@dirs, @nondirs); 956 my (@dirs, @nondirs);
769 957
770 my $statgrp = add $grp aio_group sub { 958 my $statgrp = add $grp aio_group sub {
771 $grp->result (\@dirs, \@nondirs); 959 $grp->result (\@dirs, \@nondirs);
772 }; 960 };
773 961
774 limit $statgrp $maxreq; 962 limit $statgrp $maxreq;
775 feed $statgrp sub { 963 feed $statgrp sub {
776 return unless @$entries; 964 return unless @$entries;
777 my $entry = pop @$entries; 965 my $entry = shift @$entries;
778 966
779 aioreq_pri $pri; 967 aioreq_pri $pri;
780 add $statgrp aio_stat "$path/$entry/.", sub { 968 add $statgrp aio_stat "$path/$entry/.", sub {
781 if ($_[0] < 0) { 969 if ($_[0] < 0) {
782 push @nondirs, $entry; 970 push @nondirs, $entry;
… …
855callback with the fdatasync result code. 1043callback with the fdatasync result code.
856 1044
857If this call isn't available because your OS lacks it or it couldn't be 1045If this call isn't available because your OS lacks it or it couldn't be
858detected, it will be emulated by calling C<fsync> instead. 1046detected, it will be emulated by calling C<fsync> instead.
859 1047
1048=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1049
1050Sync the data portion of the file specified by C<$offset> and C<$length>
1051to disk (but NOT the metadata), by calling the Linux-specific
1052sync_file_range call. If sync_file_range is not available or it returns
1053ENOSYS, then fdatasync or fsync is being substituted.
1054
1055C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1056C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1057C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1058manpage for details.
1059
860=item aio_pathsync $path, $callback->($status) 1060=item aio_pathsync $path, $callback->($status)
861 1061
862This request tries to open, fsync and close the given path. This is a 1062This request tries to open, fsync and close the given path. This is a
863composite request intended to sync directories after directory operations 1063composite request intended to sync directories after directory operations
864(E.g. rename). This might not work on all operating systems or have any 1064(E.g. rename). This might not work on all operating systems or have any
865specific effect, but usually it makes sure that directory changes get 1065specific effect, but usually it makes sure that directory changes get
866written to disc. It works for anything that can be opened for read-only, 1066written to disc. It works for anything that can be opened for read-only,
867not just directories. 1067not just directories.
1068
1069Future versions of this function might fall back to other methods when
1070C<fsync> on the directory fails (such as calling C<sync>).
868 1071
869Passes C<0> when everything went ok, and C<-1> on error. 1072Passes C<0> when everything went ok, and C<-1> on error.
870 1073
871=cut 1074=cut
872 1075
… …
893 }; 1096 };
894 1097
895 $grp 1098 $grp
896} 1099}
897 1100
1101=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1102
1103This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1104scalars (see the C<IO::AIO::mmap> function, although it also works on data
1105scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1106scalar must only be modified in-place while an aio operation is pending on
1107it).
1108
1109It calls the C<msync> function of your OS, if available, with the memory
1110area starting at C<$offset> in the string and ending C<$length> bytes
1111later. If C<$length> is negative, counts from the end, and if C<$length>
1112is C<undef>, then it goes till the end of the string. The flags can be
1113a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1114C<IO::AIO::MS_SYNC>.
1115
1116=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1117
1118This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1119scalars.
1120
1121It touches (reads or writes) all memory pages in the specified
1122range inside the scalar. All caveats and parameters are the same
1123as for C<aio_msync>, above, except for flags, which must be either
1124C<0> (which reads all pages and ensures they are instantiated) or
1125C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1126writing an octet from it, which dirties the page).
1127
1128=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1129
1130This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1131scalars.
1132
1133It reads in all the pages of the underlying storage into memory (if any)
1134and locks them, so they are not getting swapped/paged out or removed.
1135
1136If C<$length> is undefined, then the scalar will be locked till the end.
1137
1138On systems that do not implement C<mlock>, this function returns C<-1>
1139and sets errno to C<ENOSYS>.
1140
1141Note that the corresponding C<munlock> is synchronous and is
1142documented under L<MISCELLANEOUS FUNCTIONS>.
1143
1144Example: open a file, mmap and mlock it - both will be undone when
1145C<$data> gets destroyed.
1146
1147 open my $fh, "<", $path or die "$path: $!";
1148 my $data;
1149 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1150 aio_mlock $data; # mlock in background
1151
1152=item aio_mlockall $flags, $callback->($status)
1153
1154Calls the C<mlockall> function with the given C<$flags> (a combination of
1155C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1156
1157On systems that do not implement C<mlockall>, this function returns C<-1>
1158and sets errno to C<ENOSYS>.
1159
1160Note that the corresponding C<munlockall> is synchronous and is
1161documented under L<MISCELLANEOUS FUNCTIONS>.
1162
1163Example: asynchronously lock all current and future pages into memory.
1164
1165 aio_mlockall IO::AIO::MCL_FUTURE;
1166
898=item aio_group $callback->(...) 1167=item aio_group $callback->(...)
899 1168
900This is a very special aio request: Instead of doing something, it is a 1169This is a very special aio request: Instead of doing something, it is a
901container for other aio requests, which is useful if you want to bundle 1170container for other aio requests, which is useful if you want to bundle
902many requests into a single, composite, request with a definite callback 1171many requests into a single, composite, request with a definite callback
… …
951=item cancel $req 1220=item cancel $req
952 1221
953Cancels the request, if possible. Has the effect of skipping execution 1222Cancels the request, if possible. Has the effect of skipping execution
954when entering the B<execute> state and skipping calling the callback when 1223when entering the B<execute> state and skipping calling the callback when
955entering the the B<result> state, but will leave the request otherwise 1224entering the the B<result> state, but will leave the request otherwise
956untouched. That means that requests that currently execute will not be 1225untouched (with the exception of readdir). That means that requests that
957stopped and resources held by the request will not be freed prematurely. 1226currently execute will not be stopped and resources held by the request
1227will not be freed prematurely.
958 1228
959=item cb $req $callback->(...) 1229=item cb $req $callback->(...)
960 1230
961Replace (or simply set) the callback registered to the request. 1231Replace (or simply set) the callback registered to the request.
962 1232
… …
1036=item $grp->cancel_subs 1306=item $grp->cancel_subs
1037 1307
1038Cancel all subrequests and clears any feeder, but not the group request 1308Cancel all subrequests and clears any feeder, but not the group request
1039itself. Useful when you queued a lot of events but got a result early. 1309itself. Useful when you queued a lot of events but got a result early.
1040 1310
1311The group request will finish normally (you cannot add requests to the
1312group).
1313
1041=item $grp->result (...) 1314=item $grp->result (...)
1042 1315
1043Set the result value(s) that will be passed to the group callback when all 1316Set the result value(s) that will be passed to the group callback when all
1044subrequests have finished and set the groups errno to the current value 1317subrequests have finished and set the groups errno to the current value
1045of errno (just like calling C<errno> without an error number). By default, 1318of errno (just like calling C<errno> without an error number). By default,
… …
1060=item feed $grp $callback->($grp) 1333=item feed $grp $callback->($grp)
1061 1334
1062Sets a feeder/generator on this group: every group can have an attached 1335Sets a feeder/generator on this group: every group can have an attached
1063generator that generates requests if idle. The idea behind this is that, 1336generator that generates requests if idle. The idea behind this is that,
1064although you could just queue as many requests as you want in a group, 1337although you could just queue as many requests as you want in a group,
1065this might starve other requests for a potentially long time. For 1338this might starve other requests for a potentially long time. For example,
1066example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1339C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1067requests, delaying any later requests for a long time. 1340delaying any later requests for a long time.
1068 1341
1069To avoid this, and allow incremental generation of requests, you can 1342To avoid this, and allow incremental generation of requests, you can
1070instead a group and set a feeder on it that generates those requests. The 1343instead a group and set a feeder on it that generates those requests. The
1071feed callback will be called whenever there are few enough (see C<limit>, 1344feed callback will be called whenever there are few enough (see C<limit>,
1072below) requests active in the group itself and is expected to queue more 1345below) requests active in the group itself and is expected to queue more
… …
1076not impose any limits). 1349not impose any limits).
1077 1350
1078If the feed does not queue more requests when called, it will be 1351If the feed does not queue more requests when called, it will be
1079automatically removed from the group. 1352automatically removed from the group.
1080 1353
1081If the feed limit is C<0>, it will be set to C<2> automatically. 1354If the feed limit is C<0> when this method is called, it will be set to
1355C<2> automatically.
1082 1356
1083Example: 1357Example:
1084 1358
1085 # stat all files in @files, but only ever use four aio requests concurrently: 1359 # stat all files in @files, but only ever use four aio requests concurrently:
1086 1360
… …
1098Sets the feeder limit for the group: The feeder will be called whenever 1372Sets the feeder limit for the group: The feeder will be called whenever
1099the group contains less than this many requests. 1373the group contains less than this many requests.
1100 1374
1101Setting the limit to C<0> will pause the feeding process. 1375Setting the limit to C<0> will pause the feeding process.
1102 1376
1377The default value for the limit is C<0>, but note that setting a feeder
1378automatically bumps it up to C<2>.
1379
1103=back 1380=back
1104 1381
1105=head2 SUPPORT FUNCTIONS 1382=head2 SUPPORT FUNCTIONS
1106 1383
1107=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1384=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1109=over 4 1386=over 4
1110 1387
1111=item $fileno = IO::AIO::poll_fileno 1388=item $fileno = IO::AIO::poll_fileno
1112 1389
1113Return the I<request result pipe file descriptor>. This filehandle must be 1390Return the I<request result pipe file descriptor>. This filehandle must be
1114polled for reading by some mechanism outside this module (e.g. Event or 1391polled for reading by some mechanism outside this module (e.g. EV, Glib,
1115select, see below or the SYNOPSIS). If the pipe becomes readable you have 1392select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1116to call C<poll_cb> to check the results. 1393you have to call C<poll_cb> to check the results.
1117 1394
1118See C<poll_cb> for an example. 1395See C<poll_cb> for an example.
1119 1396
1120=item IO::AIO::poll_cb 1397=item IO::AIO::poll_cb
1121 1398
… …
1128If not all requests were processed for whatever reason, the filehandle 1405If not all requests were processed for whatever reason, the filehandle
1129will still be ready when C<poll_cb> returns, so normally you don't have to 1406will still be ready when C<poll_cb> returns, so normally you don't have to
1130do anything special to have it called later. 1407do anything special to have it called later.
1131 1408
1132Example: Install an Event watcher that automatically calls 1409Example: Install an Event watcher that automatically calls
1133IO::AIO::poll_cb with high priority: 1410IO::AIO::poll_cb with high priority (more examples can be found in the
1411SYNOPSIS section, at the top of this document):
1134 1412
1135 Event->io (fd => IO::AIO::poll_fileno, 1413 Event->io (fd => IO::AIO::poll_fileno,
1136 poll => 'r', async => 1, 1414 poll => 'r', async => 1,
1137 cb => \&IO::AIO::poll_cb); 1415 cb => \&IO::AIO::poll_cb);
1416
1417=item IO::AIO::poll_wait
1418
1419If there are any outstanding requests and none of them in the result
1420phase, wait till the result filehandle becomes ready for reading (simply
1421does a C<select> on the filehandle. This is useful if you want to
1422synchronously wait for some requests to finish).
1423
1424See C<nreqs> for an example.
1425
1426=item IO::AIO::poll
1427
1428Waits until some requests have been handled.
1429
1430Returns the number of requests processed, but is otherwise strictly
1431equivalent to:
1432
1433 IO::AIO::poll_wait, IO::AIO::poll_cb
1434
1435=item IO::AIO::flush
1436
1437Wait till all outstanding AIO requests have been handled.
1438
1439Strictly equivalent to:
1440
1441 IO::AIO::poll_wait, IO::AIO::poll_cb
1442 while IO::AIO::nreqs;
1138 1443
1139=item IO::AIO::max_poll_reqs $nreqs 1444=item IO::AIO::max_poll_reqs $nreqs
1140 1445
1141=item IO::AIO::max_poll_time $seconds 1446=item IO::AIO::max_poll_time $seconds
1142 1447
… …
1167 # use a low priority so other tasks have priority 1472 # use a low priority so other tasks have priority
1168 Event->io (fd => IO::AIO::poll_fileno, 1473 Event->io (fd => IO::AIO::poll_fileno,
1169 poll => 'r', nice => 1, 1474 poll => 'r', nice => 1,
1170 cb => &IO::AIO::poll_cb); 1475 cb => &IO::AIO::poll_cb);
1171 1476
1172=item IO::AIO::poll_wait
1173
1174If there are any outstanding requests and none of them in the result
1175phase, wait till the result filehandle becomes ready for reading (simply
1176does a C<select> on the filehandle. This is useful if you want to
1177synchronously wait for some requests to finish).
1178
1179See C<nreqs> for an example.
1180
1181=item IO::AIO::poll
1182
1183Waits until some requests have been handled.
1184
1185Returns the number of requests processed, but is otherwise strictly
1186equivalent to:
1187
1188 IO::AIO::poll_wait, IO::AIO::poll_cb
1189
1190=item IO::AIO::flush
1191
1192Wait till all outstanding AIO requests have been handled.
1193
1194Strictly equivalent to:
1195
1196 IO::AIO::poll_wait, IO::AIO::poll_cb
1197 while IO::AIO::nreqs;
1198
1199=back 1477=back
1200 1478
1201=head3 CONTROLLING THE NUMBER OF THREADS 1479=head3 CONTROLLING THE NUMBER OF THREADS
1202 1480
1203=over 1481=over
… …
1295Returns the number of requests currently in the pending state (executed, 1573Returns the number of requests currently in the pending state (executed,
1296but not yet processed by poll_cb). 1574but not yet processed by poll_cb).
1297 1575
1298=back 1576=back
1299 1577
1578=head3 MISCELLANEOUS FUNCTIONS
1579
1580IO::AIO implements some functions that might be useful, but are not
1581asynchronous.
1582
1583=over 4
1584
1585=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1586
1587Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1588but is blocking (this makes most sense if you know the input data is
1589likely cached already and the output filehandle is set to non-blocking
1590operations).
1591
1592Returns the number of bytes copied, or C<-1> on error.
1593
1594=item IO::AIO::fadvise $fh, $offset, $len, $advice
1595
1596Simply calls the C<posix_fadvise> function (see its
1597manpage for details). The following advice constants are
1598avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1599C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1600C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1601
1602On systems that do not implement C<posix_fadvise>, this function returns
1603ENOSYS, otherwise the return value of C<posix_fadvise>.
1604
1605=item IO::AIO::madvise $scalar, $offset, $len, $advice
1606
1607Simply calls the C<posix_madvise> function (see its
1608manpage for details). The following advice constants are
1609avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1610C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1611
1612On systems that do not implement C<posix_madvise>, this function returns
1613ENOSYS, otherwise the return value of C<posix_madvise>.
1614
1615=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1616
1617Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1618$scalar (see its manpage for details). The following protect
1619constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1620C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1621
1622On systems that do not implement C<mprotect>, this function returns
1623ENOSYS, otherwise the return value of C<mprotect>.
1624
1625=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1626
1627Memory-maps a file (or anonymous memory range) and attaches it to the
1628given C<$scalar>, which will act like a string scalar.
1629
1630The only operations allowed on the scalar are C<substr>/C<vec> that don't
1631change the string length, and most read-only operations such as copying it
1632or searching it with regexes and so on.
1633
1634Anything else is unsafe and will, at best, result in memory leaks.
1635
1636The memory map associated with the C<$scalar> is automatically removed
1637when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1638C<IO::AIO::munmap> functions are called.
1639
1640This calls the C<mmap>(2) function internally. See your system's manual
1641page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1642
1643The C<$length> must be larger than zero and smaller than the actual
1644filesize.
1645
1646C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1647C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1648
1649C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1650C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1651not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1652(which is set to C<MAP_ANON> if your system only provides this
1653constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1654C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1655C<IO::AIO::MAP_NONBLOCK>
1656
1657If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1658
1659C<$offset> is the offset from the start of the file - it generally must be
1660a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1661
1662Example:
1663
1664 use Digest::MD5;
1665 use IO::AIO;
1666
1667 open my $fh, "<verybigfile"
1668 or die "$!";
1669
1670 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1671 or die "verybigfile: $!";
1672
1673 my $fast_md5 = md5 $data;
1674
1675=item IO::AIO::munmap $scalar
1676
1677Removes a previous mmap and undefines the C<$scalar>.
1678
1679=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1680
1681Calls the C<munlock> function, undoing the effects of a previous
1682C<aio_mlock> call (see its description for details).
1683
1684=item IO::AIO::munlockall
1685
1686Calls the C<munlockall> function.
1687
1688On systems that do not implement C<munlockall>, this function returns
1689ENOSYS, otherwise the return value of C<munlockall>.
1690
1691=back
1692
1300=cut 1693=cut
1301 1694
1302min_parallel 8; 1695min_parallel 8;
1303 1696
1304END { flush } 1697END { flush }
1305 1698
13061; 16991;
1700
1701=head1 EVENT LOOP INTEGRATION
1702
1703It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1704automatically into many event loops:
1705
1706 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1707 use AnyEvent::AIO;
1708
1709You can also integrate IO::AIO manually into many event loops, here are
1710some examples of how to do this:
1711
1712 # EV integration
1713 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1714
1715 # Event integration
1716 Event->io (fd => IO::AIO::poll_fileno,
1717 poll => 'r',
1718 cb => \&IO::AIO::poll_cb);
1719
1720 # Glib/Gtk2 integration
1721 add_watch Glib::IO IO::AIO::poll_fileno,
1722 in => sub { IO::AIO::poll_cb; 1 };
1723
1724 # Tk integration
1725 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1726 readable => \&IO::AIO::poll_cb);
1727
1728 # Danga::Socket integration
1729 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1730 \&IO::AIO::poll_cb);
1307 1731
1308=head2 FORK BEHAVIOUR 1732=head2 FORK BEHAVIOUR
1309 1733
1310This module should do "the right thing" when the process using it forks: 1734This module should do "the right thing" when the process using it forks:
1311 1735

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