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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC vs.
Revision 1.239 by root, Thu Dec 13 02:26:28 2012 UTC

… …
168use common::sense; 168use common::sense;
169 169
170use base 'Exporter'; 170use base 'Exporter';
171 171
172BEGIN { 172BEGIN {
173 our $VERSION = '4.0'; 173 our $VERSION = '4.18';
174 174
175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 175 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 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate 178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
179 aio_pathsync aio_readahead 179 aio_pathsync aio_readahead aio_fiemap
180 aio_rename aio_link aio_move aio_copy aio_group 180 aio_rename aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 182 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 183 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 184 aio_statvfs
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202 202
203=head1 FUNCTIONS 203=head1 FUNCTIONS
204 204
205=head2 QUICK OVERVIEW 205=head2 QUICK OVERVIEW
206 206
207This section simply lists the prototypes of the most important functions 207This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 208quick reference. See the following sections for function-by-function
209documentation. 209documentation.
210 210
211 aio_wd $pathname, $callback->($wd) 211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 213 aio_close $fh, $callback->($status)
214 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 216 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 217 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 218 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 219 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 220 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 221 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 223 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 225 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 226 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
227 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 228 aio_unlink $pathname, $callback->($status)
226 aio_mknod $pathname, $mode, $dev, $callback->($status) 229 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 230 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 231 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $pathname, $callback->($link) 232 aio_readlink $pathname, $callback->($link)
… …
233 aio_rmdir $pathname, $callback->($status) 236 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 237 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 238 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 240 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238 aio_load $pathname, $data, $callback->($status) 242 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 243 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 244 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $pathname, $callback->($status) 245 aio_rmtree $pathname, $callback->($status)
243 aio_sync $callback->($status) 246 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 247 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 248 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 249 aio_fdatasync $fh, $callback->($status)
… …
271 IO::AIO::nready 274 IO::AIO::nready
272 IO::AIO::npending 275 IO::AIO::npending
273 276
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 277 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 278 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 281 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 282 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 283 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 284 IO::AIO::munlockall
280 285
281=head2 AIO REQUEST FUNCTIONS 286=head2 API NOTES
282 287
283All the C<aio_*> calls are more or less thin wrappers around the syscall 288All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 289with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 290and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will be called after 291which must be a code reference. This code reference will be called after
… …
317correct contents. 322correct contents.
318 323
319This works, btw. independent of the internal UTF-8 bit, which IO::AIO 324This works, btw. independent of the internal UTF-8 bit, which IO::AIO
320handles correctly whether it is set or not. 325handles correctly whether it is set or not.
321 326
327=head2 AIO REQUEST FUNCTIONS
328
322=over 4 329=over 4
323 330
324=item $prev_pri = aioreq_pri [$pri] 331=item $prev_pri = aioreq_pri [$pri]
325 332
326Returns the priority value that would be used for the next request and, if 333Returns the priority value that would be used for the next request and, if
… …
355 362
356 363
357=item aio_open $pathname, $flags, $mode, $callback->($fh) 364=item aio_open $pathname, $flags, $mode, $callback->($fh)
358 365
359Asynchronously open or create a file and call the callback with a newly 366Asynchronously open or create a file and call the callback with a newly
360created filehandle for the file. 367created filehandle for the file (or C<undef> in case of an error).
361 368
362The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 369The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
363for an explanation. 370for an explanation.
364 371
365The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 372The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
… …
407 414
408Or in other words: the file descriptor will be closed, but it will not be 415Or in other words: the file descriptor will be closed, but it will not be
409free for reuse until the perl filehandle is closed. 416free for reuse until the perl filehandle is closed.
410 417
411=cut 418=cut
419
420=item aio_seek $fh, $offset, $whence, $callback->($offs)
421
422Seeks the filehandle to the new C<$offset>, similarly to perl's
423C<sysseek>. The C<$whence> can use the traditional values (C<0> for
424C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
425C<IO::AIO::SEEK_END>).
426
427The resulting absolute offset will be passed to the callback, or C<-1> in
428case of an error.
429
430In theory, the C<$whence> constants could be different than the
431corresponding values from L<Fcntl>, but perl guarantees they are the same,
432so don't panic.
433
434As a GNU/Linux (and maybe Solaris) extension, also the constants
435C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
436could be found. No guarantees about suitability for use in C<aio_seek> or
437Perl's C<sysseek> can be made though, although I would naively assume they
438"just work".
412 439
413=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
414 441
415=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416 443
… …
576 namemax => 255, 603 namemax => 255,
577 frsize => 1024, 604 frsize => 1024,
578 fsid => 1810 605 fsid => 1810
579 } 606 }
580 607
608Here is a (likely partial) list of fsid values used by Linux - it is safe
609to hardcode these when the $^O is C<linux>:
610
611 0x0000adf5 adfs
612 0x0000adff affs
613 0x5346414f afs
614 0x09041934 anon-inode filesystem
615 0x00000187 autofs
616 0x42465331 befs
617 0x1badface bfs
618 0x42494e4d binfmt_misc
619 0x9123683e btrfs
620 0x0027e0eb cgroupfs
621 0xff534d42 cifs
622 0x73757245 coda
623 0x012ff7b7 coh
624 0x28cd3d45 cramfs
625 0x453dcd28 cramfs-wend (wrong endianness)
626 0x64626720 debugfs
627 0x00001373 devfs
628 0x00001cd1 devpts
629 0x0000f15f ecryptfs
630 0x00414a53 efs
631 0x0000137d ext
632 0x0000ef53 ext2/ext3
633 0x0000ef51 ext2
634 0x00004006 fat
635 0x65735546 fuseblk
636 0x65735543 fusectl
637 0x0bad1dea futexfs
638 0x01161970 gfs2
639 0x47504653 gpfs
640 0x00004244 hfs
641 0xf995e849 hpfs
642 0x958458f6 hugetlbfs
643 0x2bad1dea inotifyfs
644 0x00009660 isofs
645 0x000072b6 jffs2
646 0x3153464a jfs
647 0x6b414653 k-afs
648 0x0bd00bd0 lustre
649 0x0000137f minix
650 0x0000138f minix 30 char names
651 0x00002468 minix v2
652 0x00002478 minix v2 30 char names
653 0x00004d5a minix v3
654 0x19800202 mqueue
655 0x00004d44 msdos
656 0x0000564c novell
657 0x00006969 nfs
658 0x6e667364 nfsd
659 0x00003434 nilfs
660 0x5346544e ntfs
661 0x00009fa1 openprom
662 0x7461636F ocfs2
663 0x00009fa0 proc
664 0x6165676c pstorefs
665 0x0000002f qnx4
666 0x858458f6 ramfs
667 0x52654973 reiserfs
668 0x00007275 romfs
669 0x67596969 rpc_pipefs
670 0x73636673 securityfs
671 0xf97cff8c selinux
672 0x0000517b smb
673 0x534f434b sockfs
674 0x73717368 squashfs
675 0x62656572 sysfs
676 0x012ff7b6 sysv2
677 0x012ff7b5 sysv4
678 0x01021994 tmpfs
679 0x15013346 udf
680 0x00011954 ufs
681 0x54190100 ufs byteswapped
682 0x00009fa2 usbdevfs
683 0x01021997 v9fs
684 0xa501fcf5 vxfs
685 0xabba1974 xenfs
686 0x012ff7b4 xenix
687 0x58465342 xfs
688 0x012fd16d xia
581 689
582=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 690=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
583 691
584Works like perl's C<utime> function (including the special case of $atime 692Works like perl's C<utime> function (including the special case of $atime
585and $mtime being undef). Fractional times are supported if the underlying 693and $mtime being undef). Fractional times are supported if the underlying
… …
613=item aio_truncate $fh_or_path, $offset, $callback->($status) 721=item aio_truncate $fh_or_path, $offset, $callback->($status)
614 722
615Works like truncate(2) or ftruncate(2). 723Works like truncate(2) or ftruncate(2).
616 724
617 725
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727
728Allocates or freed disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details.
730
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
732to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE |
733IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
734
735The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>.
737
738If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740
741
618=item aio_chmod $fh_or_path, $mode, $callback->($status) 742=item aio_chmod $fh_or_path, $mode, $callback->($status)
619 743
620Works like perl's C<chmod> function. 744Works like perl's C<chmod> function.
621 745
622 746
… …
659 783
660 784
661=item aio_realpath $pathname, $callback->($path) 785=item aio_realpath $pathname, $callback->($path)
662 786
663Asynchronously make the path absolute and resolve any symlinks in 787Asynchronously make the path absolute and resolve any symlinks in
664C<$path>. The resulting path only consists of directories (Same as 788C<$path>. The resulting path only consists of directories (same as
665L<Cwd::realpath>). 789L<Cwd::realpath>).
666 790
667This request can be used to get the absolute path of the current working 791This request can be used to get the absolute path of the current working
668directory by passing it a path of F<.> (a single dot). 792directory by passing it a path of F<.> (a single dot).
669 793
… …
1057} 1181}
1058 1182
1059=item aio_rmtree $pathname, $callback->($status) 1183=item aio_rmtree $pathname, $callback->($status)
1060 1184
1061Delete a directory tree starting (and including) C<$path>, return the 1185Delete a directory tree starting (and including) C<$path>, return the
1062status of the final C<rmdir> only. This is a composite request that 1186status of the final C<rmdir> only. This is a composite request that
1063uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1187uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1064everything else. 1188everything else.
1065 1189
1066=cut 1190=cut
1067 1191
… …
1187 1311
1188This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1312This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1189scalars. 1313scalars.
1190 1314
1191It touches (reads or writes) all memory pages in the specified 1315It touches (reads or writes) all memory pages in the specified
1192range inside the scalar. All caveats and parameters are the same 1316range inside the scalar. All caveats and parameters are the same
1193as for C<aio_msync>, above, except for flags, which must be either 1317as for C<aio_msync>, above, except for flags, which must be either
1194C<0> (which reads all pages and ensures they are instantiated) or 1318C<0> (which reads all pages and ensures they are instantiated) or
1195C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1319C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1196writing an octet from it, which dirties the page). 1320writing an octet from it, which dirties the page).
1197 1321
1198=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1322=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1199 1323
1200This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1324This is a rather advanced IO::AIO call, which works best on mmap(2)ed
… …
1231documented under L<MISCELLANEOUS FUNCTIONS>. 1355documented under L<MISCELLANEOUS FUNCTIONS>.
1232 1356
1233Example: asynchronously lock all current and future pages into memory. 1357Example: asynchronously lock all current and future pages into memory.
1234 1358
1235 aio_mlockall IO::AIO::MCL_FUTURE; 1359 aio_mlockall IO::AIO::MCL_FUTURE;
1360
1361=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1362
1363Queries the extents of the given file (by calling the Linux C<FIEMAP>
1364ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1365the ioctl is not available on your OS, then this request will fail with
1366C<ENOSYS>.
1367
1368C<$start> is the starting offset to query extents for, C<$length> is the
1369size of the range to query - if it is C<undef>, then the whole file will
1370be queried.
1371
1372C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1373C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1374exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1375the data portion.
1376
1377C<$count> is the maximum number of extent records to return. If it is
1378C<undef>, then IO::AIO queries all extents of the range. As a very special
1379case, if it is C<0>, then the callback receives the number of extents
1380instead of the extents themselves (which is unreliable, see below).
1381
1382If an error occurs, the callback receives no arguments. The special
1383C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1384
1385Otherwise, the callback receives an array reference with extent
1386structures. Each extent structure is an array reference itself, with the
1387following members:
1388
1389 [$logical, $physical, $length, $flags]
1390
1391Flags is any combination of the following flag values (typically either C<0>
1392or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1393
1394C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1395C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1396C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1397C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1398C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1399C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1400
1401At the time of this writing (Linux 3.2), this requets is unreliable unless
1402C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1403it to return all extents of a range for files with large number of
1404extents. The code works around all these issues if C<$count> is undef.
1236 1405
1237=item aio_group $callback->(...) 1406=item aio_group $callback->(...)
1238 1407
1239This is a very special aio request: Instead of doing something, it is a 1408This is a very special aio request: Instead of doing something, it is a
1240container for other aio requests, which is useful if you want to bundle 1409container for other aio requests, which is useful if you want to bundle
… …
1304object. This object stores the canonicalised, absolute version of the 1473object. This object stores the canonicalised, absolute version of the
1305path, and on systems that allow it, also a directory file descriptor. 1474path, and on systems that allow it, also a directory file descriptor.
1306 1475
1307Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> 1476Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1308or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD 1477or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1309object and a pathname instead. If the pathname is absolute, the 1478object and a pathname instead (or the IO::AIO::WD object alone, which
1479gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1310IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative 1480IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1311to that IO::AIO::WD object. 1481to that IO::AIO::WD object.
1312 1482
1313For example, to get a wd object for F</etc> and then stat F<passwd> 1483For example, to get a wd object for F</etc> and then stat F<passwd>
1314inside, you would write: 1484inside, you would write:
1315 1485
… …
1323 aio_stat [$etcdir, "passwd"], sub { 1493 aio_stat [$etcdir, "passwd"], sub {
1324 # yay 1494 # yay
1325 }; 1495 };
1326 }; 1496 };
1327 1497
1328This shows that creating an IO::AIO::WD object is itself a potentially 1498That C<aio_wd> is a request and not a normal function shows that creating
1329blocking operation, which is why it is done asynchronously. 1499an IO::AIO::WD object is itself a potentially blocking operation, which is
1500why it is done asynchronously.
1501
1502To stat the directory obtained with C<aio_wd> above, one could write
1503either of the following three request calls:
1504
1505 aio_lstat "/etc" , sub { ... # pathname as normal string
1506 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1507 aio_lstat $wd , sub { ... # shorthand for the previous
1330 1508
1331As with normal pathnames, IO::AIO keeps a copy of the working directory 1509As with normal pathnames, IO::AIO keeps a copy of the working directory
1332object and the pathname string, so you could write the following without 1510object and the pathname string, so you could write the following without
1333causing any issues due to C<$path> getting reused: 1511causing any issues due to C<$path> getting reused:
1334 1512
… …
1347will still point to the original directory. Most functions accepting a 1525will still point to the original directory. Most functions accepting a
1348pathname will use the directory fd on newer systems, and the string on 1526pathname will use the directory fd on newer systems, and the string on
1349older systems. Some functions (such as realpath) will always rely on the 1527older systems. Some functions (such as realpath) will always rely on the
1350string form of the pathname. 1528string form of the pathname.
1351 1529
1352So this fucntionality is mainly useful to get some protection against 1530So this functionality is mainly useful to get some protection against
1353C<chdir>, to easily get an absolute path out of a relative path for future 1531C<chdir>, to easily get an absolute path out of a relative path for future
1354reference, and to speed up doing many operations in the same directory 1532reference, and to speed up doing many operations in the same directory
1355(e.g. when stat'ing all files in a directory). 1533(e.g. when stat'ing all files in a directory).
1356 1534
1357The following functions implement this working directory abstraction: 1535The following functions implement this working directory abstraction:
… …
1378=item IO::AIO::CWD 1556=item IO::AIO::CWD
1379 1557
1380This is a compiletime constant (object) that represents the process 1558This is a compiletime constant (object) that represents the process
1381current working directory. 1559current working directory.
1382 1560
1383Specifying this object as working directory object for a pathname is as 1561Specifying this object as working directory object for a pathname is as if
1384if the pathname would be specified directly, without a directory object, 1562the pathname would be specified directly, without a directory object. For
1385e.g., these calls are functionally identical: 1563example, these calls are functionally identical:
1386 1564
1387 aio_stat "somefile", sub { ... }; 1565 aio_stat "somefile", sub { ... };
1388 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1566 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1389 1567
1390=back 1568=back
1569
1570To recover the path associated with an IO::AIO::WD object, you can use
1571C<aio_realpath>:
1572
1573 aio_realpath $wd, sub {
1574 warn "path is $_[0]\n";
1575 };
1391 1576
1392 1577
1393=head2 IO::AIO::REQ CLASS 1578=head2 IO::AIO::REQ CLASS
1394 1579
1395All non-aggregate C<aio_*> functions return an object of this class when 1580All non-aggregate C<aio_*> functions return an object of this class when
… …
1834ENOSYS, otherwise the return value of C<mprotect>. 2019ENOSYS, otherwise the return value of C<mprotect>.
1835 2020
1836=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2021=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1837 2022
1838Memory-maps a file (or anonymous memory range) and attaches it to the 2023Memory-maps a file (or anonymous memory range) and attaches it to the
1839given C<$scalar>, which will act like a string scalar. 2024given C<$scalar>, which will act like a string scalar. Returns true on
2025success, and false otherwise.
1840 2026
1841The only operations allowed on the scalar are C<substr>/C<vec> that don't 2027The only operations allowed on the scalar are C<substr>/C<vec> that don't
1842change the string length, and most read-only operations such as copying it 2028change the string length, and most read-only operations such as copying it
1843or searching it with regexes and so on. 2029or searching it with regexes and so on.
1844 2030
… …
1897Calls the C<munlockall> function. 2083Calls the C<munlockall> function.
1898 2084
1899On systems that do not implement C<munlockall>, this function returns 2085On systems that do not implement C<munlockall>, this function returns
1900ENOSYS, otherwise the return value of C<munlockall>. 2086ENOSYS, otherwise the return value of C<munlockall>.
1901 2087
2088=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2089
2090Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2091C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2092should be the file offset.
2093
2094C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2095silently corrupt the data in this case.
2096
2097The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2098C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2099C<IO::AIO::SPLICE_F_GIFT>.
2100
2101See the C<splice(2)> manpage for details.
2102
2103=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2104
2105Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
2106description for C<IO::AIO::splice> above for details.
2107
1902=back 2108=back
1903 2109
1904=cut 2110=cut
1905 2111
1906min_parallel 8; 2112min_parallel 8;

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