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Revision 1.219 by root, Tue Mar 27 18:54:45 2012 UTC vs.
Revision 1.248 by root, Sun Jul 27 22:10:53 2014 UTC

68=head2 EXAMPLE 68=head2 EXAMPLE
69 69
70This is a simple example that uses the EV module and loads 70This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
72 72
73 use Fcntl;
74 use EV; 73 use EV;
75 use IO::AIO; 74 use IO::AIO;
76 75
77 # register the IO::AIO callback with EV 76 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 77 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
168use common::sense; 167use common::sense;
169 168
170use base 'Exporter'; 169use base 'Exporter';
171 170
172BEGIN { 171BEGIN {
173 our $VERSION = '4.12'; 172 our $VERSION = 4.31;
174 173
175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 174 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 175 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 176 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate 177 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
179 aio_pathsync aio_readahead 178 aio_pathsync aio_readahead aio_fiemap
180 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
181 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
182 aio_chmod aio_utime aio_truncate 181 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 182 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 183 aio_statvfs
202 201
203=head1 FUNCTIONS 202=head1 FUNCTIONS
204 203
205=head2 QUICK OVERVIEW 204=head2 QUICK OVERVIEW
206 205
207This section simply lists the prototypes of the most important functions 206This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 207quick reference. See the following sections for function-by-function
209documentation. 208documentation.
210 209
211 aio_wd $pathname, $callback->($wd) 210 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 211 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 212 aio_close $fh, $callback->($status)
213 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 217 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 218 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 219 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 220 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 222 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
223 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 224 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 225 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
226 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 227 aio_unlink $pathname, $callback->($status)
226 aio_mknod $pathname, $mode, $dev, $callback->($status) 228 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 229 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 230 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $pathname, $callback->($link) 231 aio_readlink $pathname, $callback->($link)
271 IO::AIO::nready 273 IO::AIO::nready
272 IO::AIO::npending 274 IO::AIO::npending
273 275
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 276 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 277 IO::AIO::fadvise $fh, $offset, $len, $advice
278 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
279 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 280 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 281 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 282 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 283 IO::AIO::munlockall
280 284
357 361
358 362
359=item aio_open $pathname, $flags, $mode, $callback->($fh) 363=item aio_open $pathname, $flags, $mode, $callback->($fh)
360 364
361Asynchronously open or create a file and call the callback with a newly 365Asynchronously open or create a file and call the callback with a newly
362created filehandle for the file. 366created filehandle for the file (or C<undef> in case of an error).
363 367
364The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 368The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
365for an explanation. 369for an explanation.
366 370
367The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 371The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
409 413
410Or in other words: the file descriptor will be closed, but it will not be 414Or in other words: the file descriptor will be closed, but it will not be
411free for reuse until the perl filehandle is closed. 415free for reuse until the perl filehandle is closed.
412 416
413=cut 417=cut
418
419=item aio_seek $fh, $offset, $whence, $callback->($offs)
420
421Seeks the filehandle to the new C<$offset>, similarly to perl's
422C<sysseek>. The C<$whence> can use the traditional values (C<0> for
423C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
424C<IO::AIO::SEEK_END>).
425
426The resulting absolute offset will be passed to the callback, or C<-1> in
427case of an error.
428
429In theory, the C<$whence> constants could be different than the
430corresponding values from L<Fcntl>, but perl guarantees they are the same,
431so don't panic.
432
433As a GNU/Linux (and maybe Solaris) extension, also the constants
434C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
435could be found. No guarantees about suitability for use in C<aio_seek> or
436Perl's C<sysseek> can be made though, although I would naively assume they
437"just work".
414 438
415=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 439=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416 440
417=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 441=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
418 442
578 namemax => 255, 602 namemax => 255,
579 frsize => 1024, 603 frsize => 1024,
580 fsid => 1810 604 fsid => 1810
581 } 605 }
582 606
607Here is a (likely partial - send me updates!) list of fsid values used by
608Linux - it is safe to hardcode these when C<$^O> is C<linux>:
609
610 0x0000adf5 adfs
611 0x0000adff affs
612 0x5346414f afs
613 0x09041934 anon-inode filesystem
614 0x00000187 autofs
615 0x42465331 befs
616 0x1badface bfs
617 0x42494e4d binfmt_misc
618 0x9123683e btrfs
619 0x0027e0eb cgroupfs
620 0xff534d42 cifs
621 0x73757245 coda
622 0x012ff7b7 coh
623 0x28cd3d45 cramfs
624 0x453dcd28 cramfs-wend (wrong endianness)
625 0x64626720 debugfs
626 0x00001373 devfs
627 0x00001cd1 devpts
628 0x0000f15f ecryptfs
629 0x00414a53 efs
630 0x0000137d ext
631 0x0000ef53 ext2/ext3
632 0x0000ef51 ext2
633 0x00004006 fat
634 0x65735546 fuseblk
635 0x65735543 fusectl
636 0x0bad1dea futexfs
637 0x01161970 gfs2
638 0x47504653 gpfs
639 0x00004244 hfs
640 0xf995e849 hpfs
641 0x958458f6 hugetlbfs
642 0x2bad1dea inotifyfs
643 0x00009660 isofs
644 0x000072b6 jffs2
645 0x3153464a jfs
646 0x6b414653 k-afs
647 0x0bd00bd0 lustre
648 0x0000137f minix
649 0x0000138f minix 30 char names
650 0x00002468 minix v2
651 0x00002478 minix v2 30 char names
652 0x00004d5a minix v3
653 0x19800202 mqueue
654 0x00004d44 msdos
655 0x0000564c novell
656 0x00006969 nfs
657 0x6e667364 nfsd
658 0x00003434 nilfs
659 0x5346544e ntfs
660 0x00009fa1 openprom
661 0x7461636F ocfs2
662 0x00009fa0 proc
663 0x6165676c pstorefs
664 0x0000002f qnx4
665 0x858458f6 ramfs
666 0x52654973 reiserfs
667 0x00007275 romfs
668 0x67596969 rpc_pipefs
669 0x73636673 securityfs
670 0xf97cff8c selinux
671 0x0000517b smb
672 0x534f434b sockfs
673 0x73717368 squashfs
674 0x62656572 sysfs
675 0x012ff7b6 sysv2
676 0x012ff7b5 sysv4
677 0x01021994 tmpfs
678 0x15013346 udf
679 0x00011954 ufs
680 0x54190100 ufs byteswapped
681 0x00009fa2 usbdevfs
682 0x01021997 v9fs
683 0xa501fcf5 vxfs
684 0xabba1974 xenfs
685 0x012ff7b4 xenix
686 0x58465342 xfs
687 0x012fd16d xia
583 688
584=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 689=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
585 690
586Works like perl's C<utime> function (including the special case of $atime 691Works like perl's C<utime> function (including the special case of $atime
587and $mtime being undef). Fractional times are supported if the underlying 692and $mtime being undef). Fractional times are supported if the underlying
615=item aio_truncate $fh_or_path, $offset, $callback->($status) 720=item aio_truncate $fh_or_path, $offset, $callback->($status)
616 721
617Works like truncate(2) or ftruncate(2). 722Works like truncate(2) or ftruncate(2).
618 723
619 724
725=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
726
727Allocates or freed disk space according to the C<$mode> argument. See the
728linux C<fallocate> docuemntation for details.
729
730C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
731to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE |
732IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
733
734The file system block size used by C<fallocate> is presumably the
735C<f_bsize> returned by C<statvfs>.
736
737If C<fallocate> isn't available or cannot be emulated (currently no
738emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
739
740
620=item aio_chmod $fh_or_path, $mode, $callback->($status) 741=item aio_chmod $fh_or_path, $mode, $callback->($status)
621 742
622Works like perl's C<chmod> function. 743Works like perl's C<chmod> function.
623 744
624 745
661 782
662 783
663=item aio_realpath $pathname, $callback->($path) 784=item aio_realpath $pathname, $callback->($path)
664 785
665Asynchronously make the path absolute and resolve any symlinks in 786Asynchronously make the path absolute and resolve any symlinks in
666C<$path>. The resulting path only consists of directories (Same as 787C<$path>. The resulting path only consists of directories (same as
667L<Cwd::realpath>). 788L<Cwd::realpath>).
668 789
669This request can be used to get the absolute path of the current working 790This request can be used to get the absolute path of the current working
670directory by passing it a path of F<.> (a single dot). 791directory by passing it a path of F<.> (a single dot).
671 792
672 793
673=item aio_rename $srcpath, $dstpath, $callback->($status) 794=item aio_rename $srcpath, $dstpath, $callback->($status)
674 795
675Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 796Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
676rename(2) and call the callback with the result code. 797rename(2) and call the callback with the result code.
798
799On systems that support the AIO::WD working directory abstraction
800natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
801of failing, C<rename> is called on the absolute path of C<$wd>.
677 802
678 803
679=item aio_mkdir $pathname, $mode, $callback->($status) 804=item aio_mkdir $pathname, $mode, $callback->($status)
680 805
681Asynchronously mkdir (create) a directory and call the callback with 806Asynchronously mkdir (create) a directory and call the callback with
685 810
686=item aio_rmdir $pathname, $callback->($status) 811=item aio_rmdir $pathname, $callback->($status)
687 812
688Asynchronously rmdir (delete) a directory and call the callback with the 813Asynchronously rmdir (delete) a directory and call the callback with the
689result code. 814result code.
815
816On systems that support the AIO::WD working directory abstraction
817natively, the case C<[$wd, "."]> is specialcased - instead of failing,
818C<rmdir> is called on the absolute path of C<$wd>.
690 819
691 820
692=item aio_readdir $pathname, $callback->($entries) 821=item aio_readdir $pathname, $callback->($entries)
693 822
694Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 823Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
1059} 1188}
1060 1189
1061=item aio_rmtree $pathname, $callback->($status) 1190=item aio_rmtree $pathname, $callback->($status)
1062 1191
1063Delete a directory tree starting (and including) C<$path>, return the 1192Delete a directory tree starting (and including) C<$path>, return the
1064status of the final C<rmdir> only. This is a composite request that 1193status of the final C<rmdir> only. This is a composite request that
1065uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1194uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1066everything else. 1195everything else.
1067 1196
1068=cut 1197=cut
1069 1198
1189 1318
1190This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1319This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1191scalars. 1320scalars.
1192 1321
1193It touches (reads or writes) all memory pages in the specified 1322It touches (reads or writes) all memory pages in the specified
1194range inside the scalar. All caveats and parameters are the same 1323range inside the scalar. All caveats and parameters are the same
1195as for C<aio_msync>, above, except for flags, which must be either 1324as for C<aio_msync>, above, except for flags, which must be either
1196C<0> (which reads all pages and ensures they are instantiated) or 1325C<0> (which reads all pages and ensures they are instantiated) or
1197C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1326C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1198writing an octet from it, which dirties the page). 1327writing an octet from it, which dirties the page).
1199 1328
1200=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1329=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1201 1330
1202This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1331This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1233documented under L<MISCELLANEOUS FUNCTIONS>. 1362documented under L<MISCELLANEOUS FUNCTIONS>.
1234 1363
1235Example: asynchronously lock all current and future pages into memory. 1364Example: asynchronously lock all current and future pages into memory.
1236 1365
1237 aio_mlockall IO::AIO::MCL_FUTURE; 1366 aio_mlockall IO::AIO::MCL_FUTURE;
1367
1368=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1369
1370Queries the extents of the given file (by calling the Linux C<FIEMAP>
1371ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1372the ioctl is not available on your OS, then this request will fail with
1373C<ENOSYS>.
1374
1375C<$start> is the starting offset to query extents for, C<$length> is the
1376size of the range to query - if it is C<undef>, then the whole file will
1377be queried.
1378
1379C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1380C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1381exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1382the data portion.
1383
1384C<$count> is the maximum number of extent records to return. If it is
1385C<undef>, then IO::AIO queries all extents of the range. As a very special
1386case, if it is C<0>, then the callback receives the number of extents
1387instead of the extents themselves (which is unreliable, see below).
1388
1389If an error occurs, the callback receives no arguments. The special
1390C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1391
1392Otherwise, the callback receives an array reference with extent
1393structures. Each extent structure is an array reference itself, with the
1394following members:
1395
1396 [$logical, $physical, $length, $flags]
1397
1398Flags is any combination of the following flag values (typically either C<0>
1399or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1400
1401C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1402C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1403C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1404C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1405C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1406C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1407
1408At the time of this writing (Linux 3.2), this requets is unreliable unless
1409C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1410it to return all extents of a range for files with large number of
1411extents. The code works around all these issues if C<$count> is undef.
1238 1412
1239=item aio_group $callback->(...) 1413=item aio_group $callback->(...)
1240 1414
1241This is a very special aio request: Instead of doing something, it is a 1415This is a very special aio request: Instead of doing something, it is a
1242container for other aio requests, which is useful if you want to bundle 1416container for other aio requests, which is useful if you want to bundle
1358will still point to the original directory. Most functions accepting a 1532will still point to the original directory. Most functions accepting a
1359pathname will use the directory fd on newer systems, and the string on 1533pathname will use the directory fd on newer systems, and the string on
1360older systems. Some functions (such as realpath) will always rely on the 1534older systems. Some functions (such as realpath) will always rely on the
1361string form of the pathname. 1535string form of the pathname.
1362 1536
1363So this fucntionality is mainly useful to get some protection against 1537So this functionality is mainly useful to get some protection against
1364C<chdir>, to easily get an absolute path out of a relative path for future 1538C<chdir>, to easily get an absolute path out of a relative path for future
1365reference, and to speed up doing many operations in the same directory 1539reference, and to speed up doing many operations in the same directory
1366(e.g. when stat'ing all files in a directory). 1540(e.g. when stat'ing all files in a directory).
1367 1541
1368The following functions implement this working directory abstraction: 1542The following functions implement this working directory abstraction:
1381passing C<undef> as working directory component of a pathname fails the 1555passing C<undef> as working directory component of a pathname fails the
1382request with C<ENOENT>, there is often no need for error checking in the 1556request with C<ENOENT>, there is often no need for error checking in the
1383C<aio_wd> callback, as future requests using the value will fail in the 1557C<aio_wd> callback, as future requests using the value will fail in the
1384expected way. 1558expected way.
1385 1559
1386If this call isn't available because your OS lacks it or it couldn't be
1387detected, it will be emulated by calling C<fsync> instead.
1388
1389=item IO::AIO::CWD 1560=item IO::AIO::CWD
1390 1561
1391This is a compiletime constant (object) that represents the process 1562This is a compiletime constant (object) that represents the process
1392current working directory. 1563current working directory.
1393 1564
1394Specifying this object as working directory object for a pathname is as 1565Specifying this object as working directory object for a pathname is as if
1395if the pathname would be specified directly, without a directory object, 1566the pathname would be specified directly, without a directory object. For
1396e.g., these calls are functionally identical: 1567example, these calls are functionally identical:
1397 1568
1398 aio_stat "somefile", sub { ... }; 1569 aio_stat "somefile", sub { ... };
1399 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1570 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1400 1571
1401=back 1572=back
1402 1573
1574To recover the path associated with an IO::AIO::WD object, you can use
1575C<aio_realpath>:
1576
1577 aio_realpath $wd, sub {
1578 warn "path is $_[0]\n";
1579 };
1580
1581Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1582sometimes, fall back to using an absolue path.
1403 1583
1404=head2 IO::AIO::REQ CLASS 1584=head2 IO::AIO::REQ CLASS
1405 1585
1406All non-aggregate C<aio_*> functions return an object of this class when 1586All non-aggregate C<aio_*> functions return an object of this class when
1407called in non-void context. 1587called in non-void context.
1585 1765
1586See C<poll_cb> for an example. 1766See C<poll_cb> for an example.
1587 1767
1588=item IO::AIO::poll_cb 1768=item IO::AIO::poll_cb
1589 1769
1590Process some outstanding events on the result pipe. You have to call 1770Process some requests that have reached the result phase (i.e. they have
1771been executed but the results are not yet reported). You have to call
1772this "regularly" to finish outstanding requests.
1773
1591this regularly. Returns C<0> if all events could be processed (or there 1774Returns C<0> if all events could be processed (or there were no
1592were no events to process), or C<-1> if it returned earlier for whatever 1775events to process), or C<-1> if it returned earlier for whatever
1593reason. Returns immediately when no events are outstanding. The amount of 1776reason. Returns immediately when no events are outstanding. The amount
1594events processed depends on the settings of C<IO::AIO::max_poll_req> and 1777of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1595C<IO::AIO::max_poll_time>. 1778C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1596 1779
1597If not all requests were processed for whatever reason, the filehandle 1780If not all requests were processed for whatever reason, the poll file
1598will still be ready when C<poll_cb> returns, so normally you don't have to 1781descriptor will still be ready when C<poll_cb> returns, so normally you
1599do anything special to have it called later. 1782don't have to do anything special to have it called later.
1600 1783
1601Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1784Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1602ready, it can be beneficial to call this function from loops which submit 1785ready, it can be beneficial to call this function from loops which submit
1603a lot of requests, to make sure the results get processed when they become 1786a lot of requests, to make sure the results get processed when they become
1604available and not just when the loop is finished and the event loop takes 1787available and not just when the loop is finished and the event loop takes
1613 poll => 'r', async => 1, 1796 poll => 'r', async => 1,
1614 cb => \&IO::AIO::poll_cb); 1797 cb => \&IO::AIO::poll_cb);
1615 1798
1616=item IO::AIO::poll_wait 1799=item IO::AIO::poll_wait
1617 1800
1618If there are any outstanding requests and none of them in the result 1801Wait until either at least one request is in the result phase or no
1619phase, wait till the result filehandle becomes ready for reading (simply 1802requests are outstanding anymore.
1620does a C<select> on the filehandle. This is useful if you want to 1803
1621synchronously wait for some requests to finish). 1804This is useful if you want to synchronously wait for some requests to
1805become ready, without actually handling them.
1622 1806
1623See C<nreqs> for an example. 1807See C<nreqs> for an example.
1624 1808
1625=item IO::AIO::poll 1809=item IO::AIO::poll
1626 1810
1747 1931
1748This is a very bad function to use in interactive programs because it 1932This is a very bad function to use in interactive programs because it
1749blocks, and a bad way to reduce concurrency because it is inexact: Better 1933blocks, and a bad way to reduce concurrency because it is inexact: Better
1750use an C<aio_group> together with a feed callback. 1934use an C<aio_group> together with a feed callback.
1751 1935
1752It's main use is in scripts without an event loop - when you want to stat 1936Its main use is in scripts without an event loop - when you want to stat
1753a lot of files, you can write somehting like this: 1937a lot of files, you can write somehting like this:
1754 1938
1755 IO::AIO::max_outstanding 32; 1939 IO::AIO::max_outstanding 32;
1756 1940
1757 for my $path (...) { 1941 for my $path (...) {
1797 1981
1798=back 1982=back
1799 1983
1800=head3 MISCELLANEOUS FUNCTIONS 1984=head3 MISCELLANEOUS FUNCTIONS
1801 1985
1802IO::AIO implements some functions that might be useful, but are not 1986IO::AIO implements some functions that are useful when you want to use
1803asynchronous. 1987some "Advanced I/O" function not available to in Perl, without going the
1988"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
1989counterpart.
1804 1990
1805=over 4 1991=over 4
1806 1992
1807=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 1993=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1808 1994
1845ENOSYS, otherwise the return value of C<mprotect>. 2031ENOSYS, otherwise the return value of C<mprotect>.
1846 2032
1847=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2033=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1848 2034
1849Memory-maps a file (or anonymous memory range) and attaches it to the 2035Memory-maps a file (or anonymous memory range) and attaches it to the
1850given C<$scalar>, which will act like a string scalar. 2036given C<$scalar>, which will act like a string scalar. Returns true on
2037success, and false otherwise.
1851 2038
1852The only operations allowed on the scalar are C<substr>/C<vec> that don't 2039The only operations allowed on the scalar are C<substr>/C<vec> that don't
1853change the string length, and most read-only operations such as copying it 2040change the string length, and most read-only operations such as copying it
1854or searching it with regexes and so on. 2041or searching it with regexes and so on.
1855 2042
1908Calls the C<munlockall> function. 2095Calls the C<munlockall> function.
1909 2096
1910On systems that do not implement C<munlockall>, this function returns 2097On systems that do not implement C<munlockall>, this function returns
1911ENOSYS, otherwise the return value of C<munlockall>. 2098ENOSYS, otherwise the return value of C<munlockall>.
1912 2099
2100=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2101
2102Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2103C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2104should be the file offset.
2105
2106C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2107silently corrupt the data in this case.
2108
2109The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2110C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2111C<IO::AIO::SPLICE_F_GIFT>.
2112
2113See the C<splice(2)> manpage for details.
2114
2115=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2116
2117Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2118description for C<IO::AIO::splice> above for details.
2119
2120=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2121
2122Attempts to query or change the pipe buffer size. Obviously works only
2123on pipes, and currently works only on GNU/Linux systems, and fails with
2124C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2125size on other systems, drop me a note.
2126
1913=back 2127=back
1914 2128
1915=cut 2129=cut
1916 2130
1917min_parallel 8; 2131min_parallel 8;

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