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Revision 1.156 by root, Tue Jun 16 23:41:59 2009 UTC vs.
Revision 1.186 by root, Thu Dec 30 07:19:31 2010 UTC

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
25 my $req = aio_unlink "/tmp/file", sub { }; 25 my $req = aio_unlink "/tmp/file", sub { };
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
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $aio_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 30
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. It is implemented as an interface to C<libeio> 34operating system supports. It is implemented as an interface to C<libeio>
99 76
100 # register the IO::AIO callback with EV 77 # register the IO::AIO callback with EV
101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102 79
103 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105 my $fh = shift 82 my $fh = shift
106 or die "error while opening: $!"; 83 or die "error while opening: $!";
107 84
108 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
109 my $size = -s $fh; 86 my $size = -s $fh;
186 163
187package IO::AIO; 164package IO::AIO;
188 165
189use Carp (); 166use Carp ();
190 167
191no warnings; 168use common::sense;
192use strict 'vars';
193 169
194use base 'Exporter'; 170use base 'Exporter';
195 171
196BEGIN { 172BEGIN {
197 our $VERSION = '3.23'; 173 our $VERSION = '3.71';
198 174
199 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
200 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
201 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
202 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
203 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
204 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
205 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);
206 184
207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 185 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 186 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209 min_parallel max_parallel max_idle 187 min_parallel max_parallel max_idle
210 nreqs nready npending nthreads 188 nreqs nready npending nthreads
211 max_poll_time max_poll_reqs); 189 max_poll_time max_poll_reqs
190 sendfile fadvise madvise
191 mmap munmap munlock munlockall);
212 192
213 push @AIO_REQ, qw(aio_busy); # not exported 193 push @AIO_REQ, qw(aio_busy); # not exported
214 194
215 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 195 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
216 196
217 require XSLoader; 197 require XSLoader;
218 XSLoader::load ("IO::AIO", $VERSION); 198 XSLoader::load ("IO::AIO", $VERSION);
219} 199}
220 200
221=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, $length = undef
273 IO::AIO::munlockall
222 274
223=head2 AIO REQUEST FUNCTIONS 275=head2 AIO REQUEST FUNCTIONS
224 276
225All the C<aio_*> calls are more or less thin wrappers around the syscall 277All the C<aio_*> calls are more or less thin wrappers around the syscall
226with the same name (sans C<aio_>). The arguments are similar or identical, 278with the same name (sans C<aio_>). The arguments are similar or identical,
306by the umask in effect then the request is being executed, so better never 358by the umask in effect then the request is being executed, so better never
307change the umask. 359change the umask.
308 360
309Example: 361Example:
310 362
311 aio_open "/etc/passwd", O_RDONLY, 0, sub { 363 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
312 if ($_[0]) { 364 if ($_[0]) {
313 print "open successful, fh is $_[0]\n"; 365 print "open successful, fh is $_[0]\n";
314 ... 366 ...
315 } else { 367 } else {
316 die "open failed: $!\n"; 368 die "open failed: $!\n";
376reading at byte offset C<$in_offset>, and starts writing at the current 428reading at byte offset C<$in_offset>, and starts writing at the current
377file offset of C<$out_fh>. Because of that, it is not safe to issue more 429file offset of C<$out_fh>. Because of that, it is not safe to issue more
378than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 430than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
379other. 431other.
380 432
433Please note that C<aio_sendfile> can read more bytes from C<$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
381This 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
382zero-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
383socket, and C<$in_fh> should refer to mmap'able file. 451socket, and C<$in_fh> should refer to an mmap'able file.
384 452
385If 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>,
386emulated, 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
387regardless of the limitations of the operating system. 456filehandle regardless of the limitations of the operating system.
388
389Please note, however, that C<aio_sendfile> can read more bytes from
390C<$in_fh> than are written, and there is no way to find out how many
391bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
392provides the number of bytes written to C<$out_fh>. Only if the result
393value equals C<$length> one can assume that C<$length> bytes have been
394read.
395 457
396 458
397=item aio_readahead $fh,$offset,$length, $callback->($retval) 459=item aio_readahead $fh,$offset,$length, $callback->($retval)
398 460
399C<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
430 $_[0] and die "stat failed: $!"; 492 $_[0] and die "stat failed: $!";
431 print "size is ", -s _, "\n"; 493 print "size is ", -s _, "\n";
432 }; 494 };
433 495
434 496
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
435=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 542=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
436 543
437Works 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
438and $mtime being undef). Fractional times are supported if the underlying 545and $mtime being undef). Fractional times are supported if the underlying
439syscalls support them. 546syscalls support them.
634 741
635=item aio_copy $srcpath, $dstpath, $callback->($status) 742=item aio_copy $srcpath, $dstpath, $callback->($status)
636 743
637Try 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
638destination) from C<$srcpath> to C<$dstpath> and call the callback with 745destination) from C<$srcpath> to C<$dstpath> and call the callback with
639the C<0> (error) or C<-1> ok. 746a status of C<0> (ok) or C<-1> (error, see C<$!>).
640 747
641This is a composite request that creates the destination file with 748This is a composite request that creates the destination file with
642mode 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
643C<aio_sendfile>, followed by restoring atime, mtime, access mode and 750C<aio_sendfile>, followed by restoring atime, mtime, access mode and
644uid/gid, in that order. 751uid/gid, in that order.
656 my $grp = aio_group $cb; 763 my $grp = aio_group $cb;
657 764
658 aioreq_pri $pri; 765 aioreq_pri $pri;
659 add $grp aio_open $src, O_RDONLY, 0, sub { 766 add $grp aio_open $src, O_RDONLY, 0, sub {
660 if (my $src_fh = $_[0]) { 767 if (my $src_fh = $_[0]) {
661 my @stat = stat $src_fh; # hmm, might bock over nfs? 768 my @stat = stat $src_fh; # hmm, might block over nfs?
662 769
663 aioreq_pri $pri; 770 aioreq_pri $pri;
664 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 {
665 if (my $dst_fh = $_[0]) { 772 if (my $dst_fh = $_[0]) {
666 aioreq_pri $pri; 773 aioreq_pri $pri;
713 820
714=item aio_move $srcpath, $dstpath, $callback->($status) 821=item aio_move $srcpath, $dstpath, $callback->($status)
715 822
716Try 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
717destination) from C<$srcpath> to C<$dstpath> and call the callback with 824destination) from C<$srcpath> to C<$dstpath> and call the callback with
718the C<0> (error) or C<-1> ok. 825a status of C<0> (ok) or C<-1> (error, see C<$!>).
719 826
720This is a composite request that tries to rename(2) the file first; if 827This is a composite request that tries to rename(2) the file first; if
721rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if 828rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
722that is successful, unlinks the C<$srcpath>. 829that is successful, unlinks the C<$srcpath>.
723 830
957(E.g. rename). This might not work on all operating systems or have any 1064(E.g. rename). This might not work on all operating systems or have any
958specific effect, but usually it makes sure that directory changes get 1065specific effect, but usually it makes sure that directory changes get
959written to disc. It works for anything that can be opened for read-only, 1066written to disc. It works for anything that can be opened for read-only,
960not just directories. 1067not just directories.
961 1068
1069Future versions of this function might fall back to other methods when
1070C<fsync> on the directory fails (such as calling C<sync>).
1071
962Passes C<0> when everything went ok, and C<-1> on error. 1072Passes C<0> when everything went ok, and C<-1> on error.
963 1073
964=cut 1074=cut
965 1075
966sub aio_pathsync($;$) { 1076sub aio_pathsync($;$) {
986 }; 1096 };
987 1097
988 $grp 1098 $grp
989} 1099}
990 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
991=item aio_group $callback->(...) 1167=item aio_group $callback->(...)
992 1168
993This 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
994container 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
995many requests into a single, composite, request with a definite callback 1171many requests into a single, composite, request with a definite callback
1130=item $grp->cancel_subs 1306=item $grp->cancel_subs
1131 1307
1132Cancel all subrequests and clears any feeder, but not the group request 1308Cancel all subrequests and clears any feeder, but not the group request
1133itself. 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.
1134 1310
1311The group request will finish normally (you cannot add requests to the
1312group).
1313
1135=item $grp->result (...) 1314=item $grp->result (...)
1136 1315
1137Set 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
1138subrequests have finished and set the groups errno to the current value 1317subrequests have finished and set the groups errno to the current value
1139of 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,
1233 1412
1234 Event->io (fd => IO::AIO::poll_fileno, 1413 Event->io (fd => IO::AIO::poll_fileno,
1235 poll => 'r', async => 1, 1414 poll => 'r', async => 1,
1236 cb => \&IO::AIO::poll_cb); 1415 cb => \&IO::AIO::poll_cb);
1237 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;
1443
1238=item IO::AIO::max_poll_reqs $nreqs 1444=item IO::AIO::max_poll_reqs $nreqs
1239 1445
1240=item IO::AIO::max_poll_time $seconds 1446=item IO::AIO::max_poll_time $seconds
1241 1447
1242These set the maximum number of requests (default C<0>, meaning infinity) 1448These set the maximum number of requests (default C<0>, meaning infinity)
1266 # use a low priority so other tasks have priority 1472 # use a low priority so other tasks have priority
1267 Event->io (fd => IO::AIO::poll_fileno, 1473 Event->io (fd => IO::AIO::poll_fileno,
1268 poll => 'r', nice => 1, 1474 poll => 'r', nice => 1,
1269 cb => &IO::AIO::poll_cb); 1475 cb => &IO::AIO::poll_cb);
1270 1476
1271=item IO::AIO::poll_wait
1272
1273If there are any outstanding requests and none of them in the result
1274phase, wait till the result filehandle becomes ready for reading (simply
1275does a C<select> on the filehandle. This is useful if you want to
1276synchronously wait for some requests to finish).
1277
1278See C<nreqs> for an example.
1279
1280=item IO::AIO::poll
1281
1282Waits until some requests have been handled.
1283
1284Returns the number of requests processed, but is otherwise strictly
1285equivalent to:
1286
1287 IO::AIO::poll_wait, IO::AIO::poll_cb
1288
1289=item IO::AIO::flush
1290
1291Wait till all outstanding AIO requests have been handled.
1292
1293Strictly equivalent to:
1294
1295 IO::AIO::poll_wait, IO::AIO::poll_cb
1296 while IO::AIO::nreqs;
1297
1298=back 1477=back
1299 1478
1300=head3 CONTROLLING THE NUMBER OF THREADS 1479=head3 CONTROLLING THE NUMBER OF THREADS
1301 1480
1302=over 1481=over
1394Returns the number of requests currently in the pending state (executed, 1573Returns the number of requests currently in the pending state (executed,
1395but not yet processed by poll_cb). 1574but not yet processed by poll_cb).
1396 1575
1397=back 1576=back
1398 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
1399=cut 1693=cut
1400 1694
1401min_parallel 8; 1695min_parallel 8;
1402 1696
1403END { flush } 1697END { flush }
1404 1698
14051; 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);
1406 1731
1407=head2 FORK BEHAVIOUR 1732=head2 FORK BEHAVIOUR
1408 1733
1409This 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:
1410 1735

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