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Revision 1.189 by root, Sun Mar 27 10:26:08 2011 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 = '3.18'; 173 our $VERSION = '3.8';
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_sync_file_range 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 idle_timeout
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);
213 192
214 push @AIO_REQ, qw(aio_busy); # not exported 193 push @AIO_REQ, qw(aio_busy); # not exported
215 194
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 195 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 196
218 require XSLoader; 197 require XSLoader;
219 XSLoader::load ("IO::AIO", $VERSION); 198 XSLoader::load ("IO::AIO", $VERSION);
220} 199}
221 200
222=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::idle_timeout $seconds
264 IO::AIO::max_outstanding $maxreqs
265 IO::AIO::nreqs
266 IO::AIO::nready
267 IO::AIO::npending
268
269 IO::AIO::sendfile $ofh, $ifh, $offset, $count
270 IO::AIO::fadvise $fh, $offset, $len, $advice
271 IO::AIO::madvise $scalar, $offset, $length, $advice
272 IO::AIO::mprotect $scalar, $offset, $length, $protect
273 IO::AIO::munlock $scalar, $offset = 0, $length = undef
274 IO::AIO::munlockall
223 275
224=head2 AIO REQUEST FUNCTIONS 276=head2 AIO REQUEST FUNCTIONS
225 277
226All the C<aio_*> calls are more or less thin wrappers around the syscall 278All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 279with the same name (sans C<aio_>). The arguments are similar or identical,
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307by the umask in effect then the request is being executed, so better never 359by the umask in effect then the request is being executed, so better never
308change the umask. 360change the umask.
309 361
310Example: 362Example:
311 363
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 364 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 365 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 366 print "open successful, fh is $_[0]\n";
315 ... 367 ...
316 } else { 368 } else {
317 die "open failed: $!\n"; 369 die "open failed: $!\n";
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343Reads or writes C<$length> bytes from or to the specified C<$fh> and 395Reads or writes C<$length> bytes from or to the specified C<$fh> and
344C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 396C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
345and calls the callback without the actual number of bytes read (or -1 on 397and calls the callback without the actual number of bytes read (or -1 on
346error, just like the syscall). 398error, just like the syscall).
347 399
400C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
401offset plus the actual number of bytes read.
402
348If C<$offset> is undefined, then the current file descriptor offset will 403If C<$offset> is undefined, then the current file descriptor offset will
349be used (and updated), otherwise the file descriptor offset will not be 404be used (and updated), otherwise the file descriptor offset will not be
350changed by these calls. 405changed by these calls.
351 406
352If C<$length> is undefined in C<aio_write>, use the remaining length of 407If C<$length> is undefined in C<aio_write>, use the remaining length of
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374reading at byte offset C<$in_offset>, and starts writing at the current 429reading at byte offset C<$in_offset>, and starts writing at the current
375file offset of C<$out_fh>. Because of that, it is not safe to issue more 430file offset of C<$out_fh>. Because of that, it is not safe to issue more
376than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 431than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
377other. 432other.
378 433
434Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
435are written, and there is no way to find out how many bytes have been read
436from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
437bytes written to C<$out_fh>. Only if the result value equals C<$length>
438one can assume that C<$length> bytes have been read.
439
440Unlike with other C<aio_> functions, it makes a lot of sense to use
441C<aio_sendfile> on non-blocking sockets, as long as one end (typically
442the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
443the socket I/O will be non-blocking. Note, however, that you can run into
444a trap where C<aio_sendfile> reads some data with readahead, then fails
445to write all data, and when the socket is ready the next time, the data
446in the cache is already lost, forcing C<aio_sendfile> to again hit the
447disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
448much better.
449
379This call tries to make use of a native C<sendfile> syscall to provide 450This call tries to make use of a native C<sendfile> syscall to provide
380zero-copy operation. For this to work, C<$out_fh> should refer to a 451zero-copy operation. For this to work, C<$out_fh> should refer to a
381socket, and C<$in_fh> should refer to mmap'able file. 452socket, and C<$in_fh> should refer to an mmap'able file.
382 453
383If the native sendfile call fails or is not implemented, it will be 454If a native sendfile cannot be found or it fails with C<ENOSYS>,
455C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
384emulated, so you can call C<aio_sendfile> on any type of filehandle 456it will be emulated, so you can call C<aio_sendfile> on any type of
385regardless of the limitations of the operating system. 457filehandle regardless of the limitations of the operating system.
386
387Please note, however, that C<aio_sendfile> can read more bytes from
388C<$in_fh> than are written, and there is no way to find out how many
389bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
390provides the number of bytes written to C<$out_fh>. Only if the result
391value equals C<$length> one can assume that C<$length> bytes have been
392read.
393 458
394 459
395=item aio_readahead $fh,$offset,$length, $callback->($retval) 460=item aio_readahead $fh,$offset,$length, $callback->($retval)
396 461
397C<aio_readahead> populates the page cache with data from a file so that 462C<aio_readahead> populates the page cache with data from a file so that
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420 485
421Currently, the stats are always 64-bit-stats, i.e. instead of returning an 486Currently, the stats are always 64-bit-stats, i.e. instead of returning an
422error when stat'ing a large file, the results will be silently truncated 487error when stat'ing a large file, the results will be silently truncated
423unless perl itself is compiled with large file support. 488unless perl itself is compiled with large file support.
424 489
490To help interpret the mode and dev/rdev stat values, IO::AIO offers the
491following constants and functions (if not implemented, the constants will
492be C<0> and the functions will either C<croak> or fall back on traditional
493behaviour).
494
495C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
496C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
497C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
498
425Example: Print the length of F</etc/passwd>: 499Example: Print the length of F</etc/passwd>:
426 500
427 aio_stat "/etc/passwd", sub { 501 aio_stat "/etc/passwd", sub {
428 $_[0] and die "stat failed: $!"; 502 $_[0] and die "stat failed: $!";
429 print "size is ", -s _, "\n"; 503 print "size is ", -s _, "\n";
430 }; 504 };
431 505
432 506
507=item aio_statvfs $fh_or_path, $callback->($statvfs)
508
509Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
510whether a file handle or path was passed.
511
512On success, the callback is passed a hash reference with the following
513members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
514C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
515is passed.
516
517The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
518C<ST_NOSUID>.
519
520The following non-POSIX IO::AIO::ST_* flag masks are defined to
521their correct value when available, or to C<0> on systems that do
522not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
523C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
524C<ST_NODIRATIME> and C<ST_RELATIME>.
525
526Example: stat C</wd> and dump out the data if successful.
527
528 aio_statvfs "/wd", sub {
529 my $f = $_[0]
530 or die "statvfs: $!";
531
532 use Data::Dumper;
533 say Dumper $f;
534 };
535
536 # result:
537 {
538 bsize => 1024,
539 bfree => 4333064312,
540 blocks => 10253828096,
541 files => 2050765568,
542 flag => 4096,
543 favail => 2042092649,
544 bavail => 4333064312,
545 ffree => 2042092649,
546 namemax => 255,
547 frsize => 1024,
548 fsid => 1810
549 }
550
551
433=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 552=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
434 553
435Works like perl's C<utime> function (including the special case of $atime 554Works like perl's C<utime> function (including the special case of $atime
436and $mtime being undef). Fractional times are supported if the underlying 555and $mtime being undef). Fractional times are supported if the underlying
437syscalls support them. 556syscalls support them.
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485 604
486The only (POSIX-) portable way of calling this function is: 605The only (POSIX-) portable way of calling this function is:
487 606
488 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 607 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
489 608
609See C<aio_stat> for info about some potentially helpful extra constants
610and functions.
490 611
491=item aio_link $srcpath, $dstpath, $callback->($status) 612=item aio_link $srcpath, $dstpath, $callback->($status)
492 613
493Asynchronously create a new link to the existing object at C<$srcpath> at 614Asynchronously create a new link to the existing object at C<$srcpath> at
494the path C<$dstpath> and call the callback with the result code. 615the path C<$dstpath> and call the callback with the result code.
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530 651
531Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 652Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
532directory (i.e. opendir + readdir + closedir). The entries will not be 653directory (i.e. opendir + readdir + closedir). The entries will not be
533sorted, and will B<NOT> include the C<.> and C<..> entries. 654sorted, and will B<NOT> include the C<.> and C<..> entries.
534 655
535The callback a single argument which is either C<undef> or an array-ref 656The callback is passed a single argument which is either C<undef> or an
536with the filenames. 657array-ref with the filenames.
658
659
660=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
661
662Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
663behaviour and output format. In case of an error, C<$entries> will be
664C<undef>.
665
666The flags are a combination of the following constants, ORed together (the
667flags will also be passed to the callback, possibly modified):
668
669=over 4
670
671=item IO::AIO::READDIR_DENTS
672
673When this flag is off, then the callback gets an arrayref with of names
674only (as with C<aio_readdir>), otherwise it gets an arrayref with
675C<[$name, $type, $inode]> arrayrefs, each describing a single directory
676entry in more detail.
677
678C<$name> is the name of the entry.
679
680C<$type> is one of the C<IO::AIO::DT_xxx> constants:
681
682C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
683C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
684C<IO::AIO::DT_WHT>.
685
686C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
687know, you have to run stat yourself. Also, for speed reasons, the C<$type>
688scalars are read-only: you can not modify them.
689
690C<$inode> is the inode number (which might not be exact on systems with 64
691bit inode numbers and 32 bit perls). This field has unspecified content on
692systems that do not deliver the inode information.
693
694=item IO::AIO::READDIR_DIRS_FIRST
695
696When this flag is set, then the names will be returned in an order where
697likely directories come first. This is useful when you need to quickly
698find directories, or you want to find all directories while avoiding to
699stat() each entry.
700
701If the system returns type information in readdir, then this is used
702to find directories directly. Otherwise, likely directories are files
703beginning with ".", or otherwise files with no dots, of which files with
704short names are tried first.
705
706=item IO::AIO::READDIR_STAT_ORDER
707
708When this flag is set, then the names will be returned in an order
709suitable for stat()'ing each one. That is, when you plan to stat()
710all files in the given directory, then the returned order will likely
711be fastest.
712
713If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
714the likely dirs come first, resulting in a less optimal stat order.
715
716=item IO::AIO::READDIR_FOUND_UNKNOWN
717
718This flag should not be set when calling C<aio_readdirx>. Instead, it
719is being set by C<aio_readdirx>, when any of the C<$type>'s found were
720C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
721C<$type>'s are known, which can be used to speed up some algorithms.
722
723=back
537 724
538 725
539=item aio_load $path, $data, $callback->($status) 726=item aio_load $path, $data, $callback->($status)
540 727
541This is a composite request that tries to fully load the given file into 728This is a composite request that tries to fully load the given file into
… …
566 753
567=item aio_copy $srcpath, $dstpath, $callback->($status) 754=item aio_copy $srcpath, $dstpath, $callback->($status)
568 755
569Try to copy the I<file> (directories not supported as either source or 756Try to copy the I<file> (directories not supported as either source or
570destination) from C<$srcpath> to C<$dstpath> and call the callback with 757destination) from C<$srcpath> to C<$dstpath> and call the callback with
571the C<0> (error) or C<-1> ok. 758a status of C<0> (ok) or C<-1> (error, see C<$!>).
572 759
573This is a composite request that creates the destination file with 760This is a composite request that creates the destination file with
574mode 0200 and copies the contents of the source file into it using 761mode 0200 and copies the contents of the source file into it using
575C<aio_sendfile>, followed by restoring atime, mtime, access mode and 762C<aio_sendfile>, followed by restoring atime, mtime, access mode and
576uid/gid, in that order. 763uid/gid, in that order.
… …
588 my $grp = aio_group $cb; 775 my $grp = aio_group $cb;
589 776
590 aioreq_pri $pri; 777 aioreq_pri $pri;
591 add $grp aio_open $src, O_RDONLY, 0, sub { 778 add $grp aio_open $src, O_RDONLY, 0, sub {
592 if (my $src_fh = $_[0]) { 779 if (my $src_fh = $_[0]) {
593 my @stat = stat $src_fh; 780 my @stat = stat $src_fh; # hmm, might block over nfs?
594 781
595 aioreq_pri $pri; 782 aioreq_pri $pri;
596 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 783 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
597 if (my $dst_fh = $_[0]) { 784 if (my $dst_fh = $_[0]) {
598 aioreq_pri $pri; 785 aioreq_pri $pri;
599 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 786 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
600 if ($_[0] == $stat[7]) { 787 if ($_[0] == $stat[7]) {
601 $grp->result (0); 788 $grp->result (0);
602 close $src_fh; 789 close $src_fh;
603 790
604 # those should not normally block. should. should. 791 my $ch = sub {
605 utime $stat[8], $stat[9], $dst; 792 aioreq_pri $pri;
606 chmod $stat[2] & 07777, $dst_fh; 793 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
607 chown $stat[4], $stat[5], $dst_fh; 794 aioreq_pri $pri;
795 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
796 aioreq_pri $pri;
797 add $grp aio_close $dst_fh;
798 }
799 };
800 };
608 801
609 aioreq_pri $pri; 802 aioreq_pri $pri;
610 add $grp aio_close $dst_fh; 803 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
804 if ($_[0] < 0 && $! == ENOSYS) {
805 aioreq_pri $pri;
806 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
807 } else {
808 $ch->();
809 }
810 };
611 } else { 811 } else {
612 $grp->result (-1); 812 $grp->result (-1);
613 close $src_fh; 813 close $src_fh;
614 close $dst_fh; 814 close $dst_fh;
615 815
… …
632 832
633=item aio_move $srcpath, $dstpath, $callback->($status) 833=item aio_move $srcpath, $dstpath, $callback->($status)
634 834
635Try to move the I<file> (directories not supported as either source or 835Try to move the I<file> (directories not supported as either source or
636destination) from C<$srcpath> to C<$dstpath> and call the callback with 836destination) from C<$srcpath> to C<$dstpath> and call the callback with
637the C<0> (error) or C<-1> ok. 837a status of C<0> (ok) or C<-1> (error, see C<$!>).
638 838
639This is a composite request that tries to rename(2) the file first; if 839This is a composite request that tries to rename(2) the file first; if
640rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if 840rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
641that is successful, unlinks the C<$srcpath>. 841that is successful, unlinks the C<$srcpath>.
642 842
… …
693 893
694Implementation notes. 894Implementation notes.
695 895
696The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 896The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
697 897
898If readdir returns file type information, then this is used directly to
899find directories.
900
698After reading the directory, the modification time, size etc. of the 901Otherwise, after reading the directory, the modification time, size etc.
699directory before and after the readdir is checked, and if they match (and 902of the directory before and after the readdir is checked, and if they
700isn't the current time), the link count will be used to decide how many 903match (and isn't the current time), the link count will be used to decide
701entries are directories (if >= 2). Otherwise, no knowledge of the number 904how many entries are directories (if >= 2). Otherwise, no knowledge of the
702of subdirectories will be assumed. 905number of subdirectories will be assumed.
703 906
704Then entries will be sorted into likely directories (everything without 907Then entries will be sorted into likely directories a non-initial dot
705a non-initial dot currently) and likely non-directories (everything 908currently) and likely non-directories (see C<aio_readdirx>). Then every
706else). Then every entry plus an appended C</.> will be C<stat>'ed, 909entry plus an appended C</.> will be C<stat>'ed, likely directories first,
707likely directories first. If that succeeds, it assumes that the entry 910in order of their inode numbers. If that succeeds, it assumes that the
708is a directory or a symlink to directory (which will be checked 911entry is a directory or a symlink to directory (which will be checked
709seperately). This is often faster than stat'ing the entry itself because 912seperately). This is often faster than stat'ing the entry itself because
710filesystems might detect the type of the entry without reading the inode 913filesystems might detect the type of the entry without reading the inode
711data (e.g. ext2fs filetype feature). 914data (e.g. ext2fs filetype feature), even on systems that cannot return
915the filetype information on readdir.
712 916
713If the known number of directories (link count - 2) has been reached, the 917If the known number of directories (link count - 2) has been reached, the
714rest of the entries is assumed to be non-directories. 918rest of the entries is assumed to be non-directories.
715 919
716This only works with certainty on POSIX (= UNIX) filesystems, which 920This only works with certainty on POSIX (= UNIX) filesystems, which
… …
738 my $now = time; 942 my $now = time;
739 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 943 my $hash1 = join ":", (stat _)[0,1,3,7,9];
740 944
741 # read the directory entries 945 # read the directory entries
742 aioreq_pri $pri; 946 aioreq_pri $pri;
743 add $grp aio_readdir $path, sub { 947 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
744 my $entries = shift 948 my $entries = shift
745 or return $grp->result (); 949 or return $grp->result ();
746 950
747 # stat the dir another time 951 # stat the dir another time
748 aioreq_pri $pri; 952 aioreq_pri $pri;
… …
754 # take the slow route if anything looks fishy 958 # take the slow route if anything looks fishy
755 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 959 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
756 $ndirs = -1; 960 $ndirs = -1;
757 } else { 961 } else {
758 # if nlink == 2, we are finished 962 # if nlink == 2, we are finished
759 # on non-posix-fs's, we rely on nlink < 2 963 # for non-posix-fs's, we rely on nlink < 2
760 $ndirs = (stat _)[3] - 2 964 $ndirs = (stat _)[3] - 2
761 or return $grp->result ([], $entries); 965 or return $grp->result ([], $entries);
762 } 966 }
763 967
764 # sort into likely dirs and likely nondirs
765 # dirs == files without ".", short entries first
766 $entries = [map $_->[0],
767 sort { $b->[1] cmp $a->[1] }
768 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
769 @$entries];
770
771 my (@dirs, @nondirs); 968 my (@dirs, @nondirs);
772 969
773 my $statgrp = add $grp aio_group sub { 970 my $statgrp = add $grp aio_group sub {
774 $grp->result (\@dirs, \@nondirs); 971 $grp->result (\@dirs, \@nondirs);
775 }; 972 };
776 973
777 limit $statgrp $maxreq; 974 limit $statgrp $maxreq;
778 feed $statgrp sub { 975 feed $statgrp sub {
779 return unless @$entries; 976 return unless @$entries;
780 my $entry = pop @$entries; 977 my $entry = shift @$entries;
781 978
782 aioreq_pri $pri; 979 aioreq_pri $pri;
783 add $statgrp aio_stat "$path/$entry/.", sub { 980 add $statgrp aio_stat "$path/$entry/.", sub {
784 if ($_[0] < 0) { 981 if ($_[0] < 0) {
785 push @nondirs, $entry; 982 push @nondirs, $entry;
… …
879(E.g. rename). This might not work on all operating systems or have any 1076(E.g. rename). This might not work on all operating systems or have any
880specific effect, but usually it makes sure that directory changes get 1077specific effect, but usually it makes sure that directory changes get
881written to disc. It works for anything that can be opened for read-only, 1078written to disc. It works for anything that can be opened for read-only,
882not just directories. 1079not just directories.
883 1080
1081Future versions of this function might fall back to other methods when
1082C<fsync> on the directory fails (such as calling C<sync>).
1083
884Passes C<0> when everything went ok, and C<-1> on error. 1084Passes C<0> when everything went ok, and C<-1> on error.
885 1085
886=cut 1086=cut
887 1087
888sub aio_pathsync($;$) { 1088sub aio_pathsync($;$) {
… …
908 }; 1108 };
909 1109
910 $grp 1110 $grp
911} 1111}
912 1112
1113=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1114
1115This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1116scalars (see the C<IO::AIO::mmap> function, although it also works on data
1117scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1118scalar must only be modified in-place while an aio operation is pending on
1119it).
1120
1121It calls the C<msync> function of your OS, if available, with the memory
1122area starting at C<$offset> in the string and ending C<$length> bytes
1123later. If C<$length> is negative, counts from the end, and if C<$length>
1124is C<undef>, then it goes till the end of the string. The flags can be
1125a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1126C<IO::AIO::MS_SYNC>.
1127
1128=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1129
1130This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1131scalars.
1132
1133It touches (reads or writes) all memory pages in the specified
1134range inside the scalar. All caveats and parameters are the same
1135as for C<aio_msync>, above, except for flags, which must be either
1136C<0> (which reads all pages and ensures they are instantiated) or
1137C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1138writing an octet from it, which dirties the page).
1139
1140=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1141
1142This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1143scalars.
1144
1145It reads in all the pages of the underlying storage into memory (if any)
1146and locks them, so they are not getting swapped/paged out or removed.
1147
1148If C<$length> is undefined, then the scalar will be locked till the end.
1149
1150On systems that do not implement C<mlock>, this function returns C<-1>
1151and sets errno to C<ENOSYS>.
1152
1153Note that the corresponding C<munlock> is synchronous and is
1154documented under L<MISCELLANEOUS FUNCTIONS>.
1155
1156Example: open a file, mmap and mlock it - both will be undone when
1157C<$data> gets destroyed.
1158
1159 open my $fh, "<", $path or die "$path: $!";
1160 my $data;
1161 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1162 aio_mlock $data; # mlock in background
1163
1164=item aio_mlockall $flags, $callback->($status)
1165
1166Calls the C<mlockall> function with the given C<$flags> (a combination of
1167C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1168
1169On systems that do not implement C<mlockall>, this function returns C<-1>
1170and sets errno to C<ENOSYS>.
1171
1172Note that the corresponding C<munlockall> is synchronous and is
1173documented under L<MISCELLANEOUS FUNCTIONS>.
1174
1175Example: asynchronously lock all current and future pages into memory.
1176
1177 aio_mlockall IO::AIO::MCL_FUTURE;
1178
913=item aio_group $callback->(...) 1179=item aio_group $callback->(...)
914 1180
915This is a very special aio request: Instead of doing something, it is a 1181This is a very special aio request: Instead of doing something, it is a
916container for other aio requests, which is useful if you want to bundle 1182container for other aio requests, which is useful if you want to bundle
917many requests into a single, composite, request with a definite callback 1183many requests into a single, composite, request with a definite callback
… …
966=item cancel $req 1232=item cancel $req
967 1233
968Cancels the request, if possible. Has the effect of skipping execution 1234Cancels the request, if possible. Has the effect of skipping execution
969when entering the B<execute> state and skipping calling the callback when 1235when entering the B<execute> state and skipping calling the callback when
970entering the the B<result> state, but will leave the request otherwise 1236entering the the B<result> state, but will leave the request otherwise
971untouched. That means that requests that currently execute will not be 1237untouched (with the exception of readdir). That means that requests that
972stopped and resources held by the request will not be freed prematurely. 1238currently execute will not be stopped and resources held by the request
1239will not be freed prematurely.
973 1240
974=item cb $req $callback->(...) 1241=item cb $req $callback->(...)
975 1242
976Replace (or simply set) the callback registered to the request. 1243Replace (or simply set) the callback registered to the request.
977 1244
… …
1050 1317
1051=item $grp->cancel_subs 1318=item $grp->cancel_subs
1052 1319
1053Cancel all subrequests and clears any feeder, but not the group request 1320Cancel all subrequests and clears any feeder, but not the group request
1054itself. Useful when you queued a lot of events but got a result early. 1321itself. Useful when you queued a lot of events but got a result early.
1322
1323The group request will finish normally (you cannot add requests to the
1324group).
1055 1325
1056=item $grp->result (...) 1326=item $grp->result (...)
1057 1327
1058Set the result value(s) that will be passed to the group callback when all 1328Set the result value(s) that will be passed to the group callback when all
1059subrequests have finished and set the groups errno to the current value 1329subrequests have finished and set the groups errno to the current value
… …
1128=over 4 1398=over 4
1129 1399
1130=item $fileno = IO::AIO::poll_fileno 1400=item $fileno = IO::AIO::poll_fileno
1131 1401
1132Return the I<request result pipe file descriptor>. This filehandle must be 1402Return the I<request result pipe file descriptor>. This filehandle must be
1133polled for reading by some mechanism outside this module (e.g. Event or 1403polled for reading by some mechanism outside this module (e.g. EV, Glib,
1134select, see below or the SYNOPSIS). If the pipe becomes readable you have 1404select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1135to call C<poll_cb> to check the results. 1405you have to call C<poll_cb> to check the results.
1136 1406
1137See C<poll_cb> for an example. 1407See C<poll_cb> for an example.
1138 1408
1139=item IO::AIO::poll_cb 1409=item IO::AIO::poll_cb
1140 1410
… …
1147If not all requests were processed for whatever reason, the filehandle 1417If not all requests were processed for whatever reason, the filehandle
1148will still be ready when C<poll_cb> returns, so normally you don't have to 1418will still be ready when C<poll_cb> returns, so normally you don't have to
1149do anything special to have it called later. 1419do anything special to have it called later.
1150 1420
1151Example: Install an Event watcher that automatically calls 1421Example: Install an Event watcher that automatically calls
1152IO::AIO::poll_cb with high priority: 1422IO::AIO::poll_cb with high priority (more examples can be found in the
1423SYNOPSIS section, at the top of this document):
1153 1424
1154 Event->io (fd => IO::AIO::poll_fileno, 1425 Event->io (fd => IO::AIO::poll_fileno,
1155 poll => 'r', async => 1, 1426 poll => 'r', async => 1,
1156 cb => \&IO::AIO::poll_cb); 1427 cb => \&IO::AIO::poll_cb);
1428
1429=item IO::AIO::poll_wait
1430
1431If there are any outstanding requests and none of them in the result
1432phase, wait till the result filehandle becomes ready for reading (simply
1433does a C<select> on the filehandle. This is useful if you want to
1434synchronously wait for some requests to finish).
1435
1436See C<nreqs> for an example.
1437
1438=item IO::AIO::poll
1439
1440Waits until some requests have been handled.
1441
1442Returns the number of requests processed, but is otherwise strictly
1443equivalent to:
1444
1445 IO::AIO::poll_wait, IO::AIO::poll_cb
1446
1447=item IO::AIO::flush
1448
1449Wait till all outstanding AIO requests have been handled.
1450
1451Strictly equivalent to:
1452
1453 IO::AIO::poll_wait, IO::AIO::poll_cb
1454 while IO::AIO::nreqs;
1157 1455
1158=item IO::AIO::max_poll_reqs $nreqs 1456=item IO::AIO::max_poll_reqs $nreqs
1159 1457
1160=item IO::AIO::max_poll_time $seconds 1458=item IO::AIO::max_poll_time $seconds
1161 1459
… …
1186 # use a low priority so other tasks have priority 1484 # use a low priority so other tasks have priority
1187 Event->io (fd => IO::AIO::poll_fileno, 1485 Event->io (fd => IO::AIO::poll_fileno,
1188 poll => 'r', nice => 1, 1486 poll => 'r', nice => 1,
1189 cb => &IO::AIO::poll_cb); 1487 cb => &IO::AIO::poll_cb);
1190 1488
1191=item IO::AIO::poll_wait
1192
1193If there are any outstanding requests and none of them in the result
1194phase, wait till the result filehandle becomes ready for reading (simply
1195does a C<select> on the filehandle. This is useful if you want to
1196synchronously wait for some requests to finish).
1197
1198See C<nreqs> for an example.
1199
1200=item IO::AIO::poll
1201
1202Waits until some requests have been handled.
1203
1204Returns the number of requests processed, but is otherwise strictly
1205equivalent to:
1206
1207 IO::AIO::poll_wait, IO::AIO::poll_cb
1208
1209=item IO::AIO::flush
1210
1211Wait till all outstanding AIO requests have been handled.
1212
1213Strictly equivalent to:
1214
1215 IO::AIO::poll_wait, IO::AIO::poll_cb
1216 while IO::AIO::nreqs;
1217
1218=back 1489=back
1219 1490
1220=head3 CONTROLLING THE NUMBER OF THREADS 1491=head3 CONTROLLING THE NUMBER OF THREADS
1221 1492
1222=over 1493=over
… …
1255 1526
1256Under normal circumstances you don't need to call this function. 1527Under normal circumstances you don't need to call this function.
1257 1528
1258=item IO::AIO::max_idle $nthreads 1529=item IO::AIO::max_idle $nthreads
1259 1530
1260Limit the number of threads (default: 4) that are allowed to idle (i.e., 1531Limit the number of threads (default: 4) that are allowed to idle
1261threads that did not get a request to process within 10 seconds). That 1532(i.e., threads that did not get a request to process within the idle
1262means if a thread becomes idle while C<$nthreads> other threads are also 1533timeout (default: 10 seconds). That means if a thread becomes idle while
1263idle, it will free its resources and exit. 1534C<$nthreads> other threads are also idle, it will free its resources and
1535exit.
1264 1536
1265This is useful when you allow a large number of threads (e.g. 100 or 1000) 1537This is useful when you allow a large number of threads (e.g. 100 or 1000)
1266to allow for extremely high load situations, but want to free resources 1538to allow for extremely high load situations, but want to free resources
1267under normal circumstances (1000 threads can easily consume 30MB of RAM). 1539under normal circumstances (1000 threads can easily consume 30MB of RAM).
1268 1540
1269The default is probably ok in most situations, especially if thread 1541The default is probably ok in most situations, especially if thread
1270creation is fast. If thread creation is very slow on your system you might 1542creation is fast. If thread creation is very slow on your system you might
1271want to use larger values. 1543want to use larger values.
1544
1545=item IO::AIO::idle_timeout $seconds
1546
1547Sets the minimum idle timeout (default 10) after which worker threads are
1548allowed to exit. SEe C<IO::AIO::max_idle>.
1272 1549
1273=item IO::AIO::max_outstanding $maxreqs 1550=item IO::AIO::max_outstanding $maxreqs
1274 1551
1275This is a very bad function to use in interactive programs because it 1552This is a very bad function to use in interactive programs because it
1276blocks, and a bad way to reduce concurrency because it is inexact: Better 1553blocks, and a bad way to reduce concurrency because it is inexact: Better
… …
1314Returns the number of requests currently in the pending state (executed, 1591Returns the number of requests currently in the pending state (executed,
1315but not yet processed by poll_cb). 1592but not yet processed by poll_cb).
1316 1593
1317=back 1594=back
1318 1595
1596=head3 MISCELLANEOUS FUNCTIONS
1597
1598IO::AIO implements some functions that might be useful, but are not
1599asynchronous.
1600
1601=over 4
1602
1603=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1604
1605Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1606but is blocking (this makes most sense if you know the input data is
1607likely cached already and the output filehandle is set to non-blocking
1608operations).
1609
1610Returns the number of bytes copied, or C<-1> on error.
1611
1612=item IO::AIO::fadvise $fh, $offset, $len, $advice
1613
1614Simply calls the C<posix_fadvise> function (see its
1615manpage for details). The following advice constants are
1616avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1617C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1618C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1619
1620On systems that do not implement C<posix_fadvise>, this function returns
1621ENOSYS, otherwise the return value of C<posix_fadvise>.
1622
1623=item IO::AIO::madvise $scalar, $offset, $len, $advice
1624
1625Simply calls the C<posix_madvise> function (see its
1626manpage for details). The following advice constants are
1627avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1628C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1629
1630On systems that do not implement C<posix_madvise>, this function returns
1631ENOSYS, otherwise the return value of C<posix_madvise>.
1632
1633=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1634
1635Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1636$scalar (see its manpage for details). The following protect
1637constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1638C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1639
1640On systems that do not implement C<mprotect>, this function returns
1641ENOSYS, otherwise the return value of C<mprotect>.
1642
1643=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1644
1645Memory-maps a file (or anonymous memory range) and attaches it to the
1646given C<$scalar>, which will act like a string scalar.
1647
1648The only operations allowed on the scalar are C<substr>/C<vec> that don't
1649change the string length, and most read-only operations such as copying it
1650or searching it with regexes and so on.
1651
1652Anything else is unsafe and will, at best, result in memory leaks.
1653
1654The memory map associated with the C<$scalar> is automatically removed
1655when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1656C<IO::AIO::munmap> functions are called.
1657
1658This calls the C<mmap>(2) function internally. See your system's manual
1659page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1660
1661The C<$length> must be larger than zero and smaller than the actual
1662filesize.
1663
1664C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1665C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1666
1667C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1668C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1669not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1670(which is set to C<MAP_ANON> if your system only provides this
1671constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1672C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1673C<IO::AIO::MAP_NONBLOCK>
1674
1675If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1676
1677C<$offset> is the offset from the start of the file - it generally must be
1678a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1679
1680Example:
1681
1682 use Digest::MD5;
1683 use IO::AIO;
1684
1685 open my $fh, "<verybigfile"
1686 or die "$!";
1687
1688 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1689 or die "verybigfile: $!";
1690
1691 my $fast_md5 = md5 $data;
1692
1693=item IO::AIO::munmap $scalar
1694
1695Removes a previous mmap and undefines the C<$scalar>.
1696
1697=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1698
1699Calls the C<munlock> function, undoing the effects of a previous
1700C<aio_mlock> call (see its description for details).
1701
1702=item IO::AIO::munlockall
1703
1704Calls the C<munlockall> function.
1705
1706On systems that do not implement C<munlockall>, this function returns
1707ENOSYS, otherwise the return value of C<munlockall>.
1708
1709=back
1710
1319=cut 1711=cut
1320 1712
1321min_parallel 8; 1713min_parallel 8;
1322 1714
1323END { flush } 1715END { flush }
1324 1716
13251; 17171;
1718
1719=head1 EVENT LOOP INTEGRATION
1720
1721It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1722automatically into many event loops:
1723
1724 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1725 use AnyEvent::AIO;
1726
1727You can also integrate IO::AIO manually into many event loops, here are
1728some examples of how to do this:
1729
1730 # EV integration
1731 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1732
1733 # Event integration
1734 Event->io (fd => IO::AIO::poll_fileno,
1735 poll => 'r',
1736 cb => \&IO::AIO::poll_cb);
1737
1738 # Glib/Gtk2 integration
1739 add_watch Glib::IO IO::AIO::poll_fileno,
1740 in => sub { IO::AIO::poll_cb; 1 };
1741
1742 # Tk integration
1743 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1744 readable => \&IO::AIO::poll_cb);
1745
1746 # Danga::Socket integration
1747 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1748 \&IO::AIO::poll_cb);
1326 1749
1327=head2 FORK BEHAVIOUR 1750=head2 FORK BEHAVIOUR
1328 1751
1329This module should do "the right thing" when the process using it forks: 1752This module should do "the right thing" when the process using it forks:
1330 1753

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