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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.216 by root, Sun Oct 9 08:24:49 2011 UTC vs.
Revision 1.264 by root, Mon Jul 18 07:48:01 2016 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;
95 94
96 # file contents now in $contents 95 # file contents now in $contents
97 print $contents; 96 print $contents;
98 97
99 # exit event loop and program 98 # exit event loop and program
100 EV::unloop; 99 EV::break;
101 }; 100 };
102 }; 101 };
103 102
104 # possibly queue up other requests, or open GUI windows, 103 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 104 # check for sockets etc. etc.
106 105
107 # process events as long as there are some: 106 # process events as long as there are some:
108 EV::loop; 107 EV::run;
109 108
110=head1 REQUEST ANATOMY AND LIFETIME 109=head1 REQUEST ANATOMY AND LIFETIME
111 110
112Every C<aio_*> function creates a request. which is a C data structure not 111Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 112directly visible to Perl.
168use common::sense; 167use common::sense;
169 168
170use base 'Exporter'; 169use base 'Exporter';
171 170
172BEGIN { 171BEGIN {
173 our $VERSION = '4.1'; 172 our $VERSION = 4.34;
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_fcntl aio_ioctl
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate 177 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead 178 aio_pathsync aio_readahead aio_fiemap aio_allocate
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)
230 aio_realpath $pathname, $callback->($link) 232 aio_realpath $pathname, $callback->($path)
231 aio_rename $srcpath, $dstpath, $callback->($status) 233 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 234 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 235 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 236 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 237 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
238 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 240 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
239 aio_load $pathname, $data, $callback->($status) 241 aio_load $pathname, $data, $callback->($status)
240 aio_copy $srcpath, $dstpath, $callback->($status) 242 aio_copy $srcpath, $dstpath, $callback->($status)
241 aio_move $srcpath, $dstpath, $callback->($status) 243 aio_move $srcpath, $dstpath, $callback->($status)
242 aio_rmtree $pathname, $callback->($status) 244 aio_rmtree $pathname, $callback->($status)
245 aio_fcntl $fh, $cmd, $arg, $callback->($status)
246 aio_ioctl $fh, $request, $buf, $callback->($status)
243 aio_sync $callback->($status) 247 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 248 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 249 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 250 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 251 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
271 IO::AIO::nready 275 IO::AIO::nready
272 IO::AIO::npending 276 IO::AIO::npending
273 277
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 278 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 279 IO::AIO::fadvise $fh, $offset, $len, $advice
280 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
281 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 282 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 283 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 284 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 285 IO::AIO::munlockall
280 286
281=head2 AIO REQUEST FUNCTIONS 287=head2 API NOTES
282 288
283All the C<aio_*> calls are more or less thin wrappers around the syscall 289All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 290with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 291and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will be called after 292which must be a code reference. This code reference will be called after
317correct contents. 323correct contents.
318 324
319This works, btw. independent of the internal UTF-8 bit, which IO::AIO 325This works, btw. independent of the internal UTF-8 bit, which IO::AIO
320handles correctly whether it is set or not. 326handles correctly whether it is set or not.
321 327
328=head2 AIO REQUEST FUNCTIONS
329
322=over 4 330=over 4
323 331
324=item $prev_pri = aioreq_pri [$pri] 332=item $prev_pri = aioreq_pri [$pri]
325 333
326Returns the priority value that would be used for the next request and, if 334Returns the priority value that would be used for the next request and, if
355 363
356 364
357=item aio_open $pathname, $flags, $mode, $callback->($fh) 365=item aio_open $pathname, $flags, $mode, $callback->($fh)
358 366
359Asynchronously open or create a file and call the callback with a newly 367Asynchronously open or create a file and call the callback with a newly
360created filehandle for the file. 368created filehandle for the file (or C<undef> in case of an error).
361 369
362The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 370The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
363for an explanation. 371for an explanation.
364 372
365The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 373The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
388following POSIX and non-POSIX constants are available (missing ones on 396following POSIX and non-POSIX constants are available (missing ones on
389your system are, as usual, C<0>): 397your system are, as usual, C<0>):
390 398
391C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 399C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
392C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 400C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
393C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 401C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
394 402
395 403
396=item aio_close $fh, $callback->($status) 404=item aio_close $fh, $callback->($status)
397 405
398Asynchronously close a file and call the callback with the result 406Asynchronously close a file and call the callback with the result
407 415
408Or in other words: the file descriptor will be closed, but it will not be 416Or in other words: the file descriptor will be closed, but it will not be
409free for reuse until the perl filehandle is closed. 417free for reuse until the perl filehandle is closed.
410 418
411=cut 419=cut
420
421=item aio_seek $fh, $offset, $whence, $callback->($offs)
422
423Seeks the filehandle to the new C<$offset>, similarly to perl's
424C<sysseek>. The C<$whence> can use the traditional values (C<0> for
425C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
426C<IO::AIO::SEEK_END>).
427
428The resulting absolute offset will be passed to the callback, or C<-1> in
429case of an error.
430
431In theory, the C<$whence> constants could be different than the
432corresponding values from L<Fcntl>, but perl guarantees they are the same,
433so don't panic.
434
435As a GNU/Linux (and maybe Solaris) extension, also the constants
436C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
437could be found. No guarantees about suitability for use in C<aio_seek> or
438Perl's C<sysseek> can be made though, although I would naively assume they
439"just work".
412 440
413=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 441=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
414 442
415=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 443=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416 444
482As native sendfile syscalls (as practically any non-POSIX interface hacked 510As native sendfile syscalls (as practically any non-POSIX interface hacked
483together in a hurry to improve benchmark numbers) tend to be rather buggy 511together in a hurry to improve benchmark numbers) tend to be rather buggy
484on many systems, this implementation tries to work around some known bugs 512on many systems, this implementation tries to work around some known bugs
485in Linux and FreeBSD kernels (probably others, too), but that might fail, 513in Linux and FreeBSD kernels (probably others, too), but that might fail,
486so you really really should check the return value of C<aio_sendfile> - 514so you really really should check the return value of C<aio_sendfile> -
487fewre bytes than expected might have been transferred. 515fewer bytes than expected might have been transferred.
488 516
489 517
490=item aio_readahead $fh,$offset,$length, $callback->($retval) 518=item aio_readahead $fh,$offset,$length, $callback->($retval)
491 519
492C<aio_readahead> populates the page cache with data from a file so that 520C<aio_readahead> populates the page cache with data from a file so that
496whole pages, so that offset is effectively rounded down to a page boundary 524whole pages, so that offset is effectively rounded down to a page boundary
497and bytes are read up to the next page boundary greater than or equal to 525and bytes are read up to the next page boundary greater than or equal to
498(off-set+length). C<aio_readahead> does not read beyond the end of the 526(off-set+length). C<aio_readahead> does not read beyond the end of the
499file. The current file offset of the file is left unchanged. 527file. The current file offset of the file is left unchanged.
500 528
501If that syscall doesn't exist (likely if your OS isn't Linux) it will be 529If that syscall doesn't exist (likely if your kernel isn't Linux) it will
502emulated by simply reading the data, which would have a similar effect. 530be emulated by simply reading the data, which would have a similar effect.
503 531
504 532
505=item aio_stat $fh_or_path, $callback->($status) 533=item aio_stat $fh_or_path, $callback->($status)
506 534
507=item aio_lstat $fh, $callback->($status) 535=item aio_lstat $fh, $callback->($status)
576 namemax => 255, 604 namemax => 255,
577 frsize => 1024, 605 frsize => 1024,
578 fsid => 1810 606 fsid => 1810
579 } 607 }
580 608
609Here is a (likely partial - send me updates!) list of fsid values used by
610Linux - it is safe to hardcode these when C<$^O> is C<linux>:
611
612 0x0000adf5 adfs
613 0x0000adff affs
614 0x5346414f afs
615 0x09041934 anon-inode filesystem
616 0x00000187 autofs
617 0x42465331 befs
618 0x1badface bfs
619 0x42494e4d binfmt_misc
620 0x9123683e btrfs
621 0x0027e0eb cgroupfs
622 0xff534d42 cifs
623 0x73757245 coda
624 0x012ff7b7 coh
625 0x28cd3d45 cramfs
626 0x453dcd28 cramfs-wend (wrong endianness)
627 0x64626720 debugfs
628 0x00001373 devfs
629 0x00001cd1 devpts
630 0x0000f15f ecryptfs
631 0x00414a53 efs
632 0x0000137d ext
633 0x0000ef53 ext2/ext3/ext4
634 0x0000ef51 ext2
635 0xf2f52010 f2fs
636 0x00004006 fat
637 0x65735546 fuseblk
638 0x65735543 fusectl
639 0x0bad1dea futexfs
640 0x01161970 gfs2
641 0x47504653 gpfs
642 0x00004244 hfs
643 0xf995e849 hpfs
644 0x00c0ffee hostfs
645 0x958458f6 hugetlbfs
646 0x2bad1dea inotifyfs
647 0x00009660 isofs
648 0x000072b6 jffs2
649 0x3153464a jfs
650 0x6b414653 k-afs
651 0x0bd00bd0 lustre
652 0x0000137f minix
653 0x0000138f minix 30 char names
654 0x00002468 minix v2
655 0x00002478 minix v2 30 char names
656 0x00004d5a minix v3
657 0x19800202 mqueue
658 0x00004d44 msdos
659 0x0000564c novell
660 0x00006969 nfs
661 0x6e667364 nfsd
662 0x00003434 nilfs
663 0x5346544e ntfs
664 0x00009fa1 openprom
665 0x7461636F ocfs2
666 0x00009fa0 proc
667 0x6165676c pstorefs
668 0x0000002f qnx4
669 0x68191122 qnx6
670 0x858458f6 ramfs
671 0x52654973 reiserfs
672 0x00007275 romfs
673 0x67596969 rpc_pipefs
674 0x73636673 securityfs
675 0xf97cff8c selinux
676 0x0000517b smb
677 0x534f434b sockfs
678 0x73717368 squashfs
679 0x62656572 sysfs
680 0x012ff7b6 sysv2
681 0x012ff7b5 sysv4
682 0x01021994 tmpfs
683 0x15013346 udf
684 0x00011954 ufs
685 0x54190100 ufs byteswapped
686 0x00009fa2 usbdevfs
687 0x01021997 v9fs
688 0xa501fcf5 vxfs
689 0xabba1974 xenfs
690 0x012ff7b4 xenix
691 0x58465342 xfs
692 0x012fd16d xia
581 693
582=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 694=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
583 695
584Works like perl's C<utime> function (including the special case of $atime 696Works like perl's C<utime> function (including the special case of $atime
585and $mtime being undef). Fractional times are supported if the underlying 697and $mtime being undef). Fractional times are supported if the underlying
613=item aio_truncate $fh_or_path, $offset, $callback->($status) 725=item aio_truncate $fh_or_path, $offset, $callback->($status)
614 726
615Works like truncate(2) or ftruncate(2). 727Works like truncate(2) or ftruncate(2).
616 728
617 729
730=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
731
732Allocates or frees disk space according to the C<$mode> argument. See the
733linux C<fallocate> documentation for details.
734
735C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
736space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
737to deallocate a file range.
738
739IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
740(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
741your L<fallocate(2)> manpage).
742
743The file system block size used by C<fallocate> is presumably the
744C<f_bsize> returned by C<statvfs>.
745
746If C<fallocate> isn't available or cannot be emulated (currently no
747emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
748
749
618=item aio_chmod $fh_or_path, $mode, $callback->($status) 750=item aio_chmod $fh_or_path, $mode, $callback->($status)
619 751
620Works like perl's C<chmod> function. 752Works like perl's C<chmod> function.
621 753
622 754
659 791
660 792
661=item aio_realpath $pathname, $callback->($path) 793=item aio_realpath $pathname, $callback->($path)
662 794
663Asynchronously make the path absolute and resolve any symlinks in 795Asynchronously make the path absolute and resolve any symlinks in
664C<$path>. The resulting path only consists of directories (Same as 796C<$path>. The resulting path only consists of directories (same as
665L<Cwd::realpath>). 797L<Cwd::realpath>).
666 798
667This request can be used to get the absolute path of the current working 799This request can be used to get the absolute path of the current working
668directory by passing it a path of F<.> (a single dot). 800directory by passing it a path of F<.> (a single dot).
669 801
670 802
671=item aio_rename $srcpath, $dstpath, $callback->($status) 803=item aio_rename $srcpath, $dstpath, $callback->($status)
672 804
673Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 805Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
674rename(2) and call the callback with the result code. 806rename(2) and call the callback with the result code.
807
808On systems that support the AIO::WD working directory abstraction
809natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
810of failing, C<rename> is called on the absolute path of C<$wd>.
675 811
676 812
677=item aio_mkdir $pathname, $mode, $callback->($status) 813=item aio_mkdir $pathname, $mode, $callback->($status)
678 814
679Asynchronously mkdir (create) a directory and call the callback with 815Asynchronously mkdir (create) a directory and call the callback with
683 819
684=item aio_rmdir $pathname, $callback->($status) 820=item aio_rmdir $pathname, $callback->($status)
685 821
686Asynchronously rmdir (delete) a directory and call the callback with the 822Asynchronously rmdir (delete) a directory and call the callback with the
687result code. 823result code.
824
825On systems that support the AIO::WD working directory abstraction
826natively, the case C<[$wd, "."]> is specialcased - instead of failing,
827C<rmdir> is called on the absolute path of C<$wd>.
688 828
689 829
690=item aio_readdir $pathname, $callback->($entries) 830=item aio_readdir $pathname, $callback->($entries)
691 831
692Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 832Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
1057} 1197}
1058 1198
1059=item aio_rmtree $pathname, $callback->($status) 1199=item aio_rmtree $pathname, $callback->($status)
1060 1200
1061Delete a directory tree starting (and including) C<$path>, return the 1201Delete a directory tree starting (and including) C<$path>, return the
1062status of the final C<rmdir> only. This is a composite request that 1202status of the final C<rmdir> only. This is a composite request that
1063uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1203uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1064everything else. 1204everything else.
1065 1205
1066=cut 1206=cut
1067 1207
1088 add $grp $dirgrp; 1228 add $grp $dirgrp;
1089 }; 1229 };
1090 1230
1091 $grp 1231 $grp
1092} 1232}
1233
1234=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1235
1236=item aio_ioctl $fh, $request, $buf, $callback->($status)
1237
1238These work just like the C<fcntl> and C<ioctl> built-in functions, except
1239they execute asynchronously and pass the return value to the callback.
1240
1241Both calls can be used for a lot of things, some of which make more sense
1242to run asynchronously in their own thread, while some others make less
1243sense. For example, calls that block waiting for external events, such
1244as locking, will also lock down an I/O thread while it is waiting, which
1245can deadlock the whole I/O system. At the same time, there might be no
1246alternative to using a thread to wait.
1247
1248So in general, you should only use these calls for things that do
1249(filesystem) I/O, not for things that wait for other events (network,
1250other processes), although if you are careful and know what you are doing,
1251you still can.
1252
1253The following constants are available (missing ones are, as usual C<0>):
1254
1255C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1256
1257C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1258C<FS_IOC_FIEMAP>.
1259
1260C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1261C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1262
1263C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1264C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1265C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1266C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1267C<FS_FL_USER_MODIFIABLE>.
1268
1269C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1270C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1271C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1272C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1093 1273
1094=item aio_sync $callback->($status) 1274=item aio_sync $callback->($status)
1095 1275
1096Asynchronously call sync and call the callback when finished. 1276Asynchronously call sync and call the callback when finished.
1097 1277
1187 1367
1188This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1368This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1189scalars. 1369scalars.
1190 1370
1191It touches (reads or writes) all memory pages in the specified 1371It touches (reads or writes) all memory pages in the specified
1192range inside the scalar. All caveats and parameters are the same 1372range inside the scalar. All caveats and parameters are the same
1193as for C<aio_msync>, above, except for flags, which must be either 1373as for C<aio_msync>, above, except for flags, which must be either
1194C<0> (which reads all pages and ensures they are instantiated) or 1374C<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 1375C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1196writing an octet from it, which dirties the page). 1376writing an octet from it, which dirties the page).
1197 1377
1198=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1378=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1199 1379
1200This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1380This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1231documented under L<MISCELLANEOUS FUNCTIONS>. 1411documented under L<MISCELLANEOUS FUNCTIONS>.
1232 1412
1233Example: asynchronously lock all current and future pages into memory. 1413Example: asynchronously lock all current and future pages into memory.
1234 1414
1235 aio_mlockall IO::AIO::MCL_FUTURE; 1415 aio_mlockall IO::AIO::MCL_FUTURE;
1416
1417=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1418
1419Queries the extents of the given file (by calling the Linux C<FIEMAP>
1420ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1421the ioctl is not available on your OS, then this request will fail with
1422C<ENOSYS>.
1423
1424C<$start> is the starting offset to query extents for, C<$length> is the
1425size of the range to query - if it is C<undef>, then the whole file will
1426be queried.
1427
1428C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1429C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1430exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1431the data portion.
1432
1433C<$count> is the maximum number of extent records to return. If it is
1434C<undef>, then IO::AIO queries all extents of the range. As a very special
1435case, if it is C<0>, then the callback receives the number of extents
1436instead of the extents themselves (which is unreliable, see below).
1437
1438If an error occurs, the callback receives no arguments. The special
1439C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1440
1441Otherwise, the callback receives an array reference with extent
1442structures. Each extent structure is an array reference itself, with the
1443following members:
1444
1445 [$logical, $physical, $length, $flags]
1446
1447Flags is any combination of the following flag values (typically either C<0>
1448or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1449
1450C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1451C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1452C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1453C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1454C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1455C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1456
1457At the time of this writing (Linux 3.2), this requets is unreliable unless
1458C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1459it to return all extents of a range for files with large number of
1460extents. The code works around all these issues if C<$count> is undef.
1236 1461
1237=item aio_group $callback->(...) 1462=item aio_group $callback->(...)
1238 1463
1239This is a very special aio request: Instead of doing something, it is a 1464This is a very special aio request: Instead of doing something, it is a
1240container for other aio requests, which is useful if you want to bundle 1465container for other aio requests, which is useful if you want to bundle
1324 aio_stat [$etcdir, "passwd"], sub { 1549 aio_stat [$etcdir, "passwd"], sub {
1325 # yay 1550 # yay
1326 }; 1551 };
1327 }; 1552 };
1328 1553
1329That C<aio_wd> is a request and not a normal function shows that creating 1554The fact that C<aio_wd> is a request and not a normal function shows that
1330an IO::AIO::WD object is itself a potentially blocking operation, which is 1555creating an IO::AIO::WD object is itself a potentially blocking operation,
1331why it is done asynchronously. 1556which is why it is done asynchronously.
1332 1557
1333To stat the directory obtained with C<aio_wd> above, one could write 1558To stat the directory obtained with C<aio_wd> above, one could write
1334either of the following three request calls: 1559either of the following three request calls:
1335 1560
1336 aio_lstat "/etc" , sub { ... # pathname as normal string 1561 aio_lstat "/etc" , sub { ... # pathname as normal string
1356will still point to the original directory. Most functions accepting a 1581will still point to the original directory. Most functions accepting a
1357pathname will use the directory fd on newer systems, and the string on 1582pathname will use the directory fd on newer systems, and the string on
1358older systems. Some functions (such as realpath) will always rely on the 1583older systems. Some functions (such as realpath) will always rely on the
1359string form of the pathname. 1584string form of the pathname.
1360 1585
1361So this fucntionality is mainly useful to get some protection against 1586So this functionality is mainly useful to get some protection against
1362C<chdir>, to easily get an absolute path out of a relative path for future 1587C<chdir>, to easily get an absolute path out of a relative path for future
1363reference, and to speed up doing many operations in the same directory 1588reference, and to speed up doing many operations in the same directory
1364(e.g. when stat'ing all files in a directory). 1589(e.g. when stat'ing all files in a directory).
1365 1590
1366The following functions implement this working directory abstraction: 1591The following functions implement this working directory abstraction:
1379passing C<undef> as working directory component of a pathname fails the 1604passing C<undef> as working directory component of a pathname fails the
1380request with C<ENOENT>, there is often no need for error checking in the 1605request with C<ENOENT>, there is often no need for error checking in the
1381C<aio_wd> callback, as future requests using the value will fail in the 1606C<aio_wd> callback, as future requests using the value will fail in the
1382expected way. 1607expected way.
1383 1608
1384If this call isn't available because your OS lacks it or it couldn't be
1385detected, it will be emulated by calling C<fsync> instead.
1386
1387=item IO::AIO::CWD 1609=item IO::AIO::CWD
1388 1610
1389This is a compiletime constant (object) that represents the process 1611This is a compiletime constant (object) that represents the process
1390current working directory. 1612current working directory.
1391 1613
1392Specifying this object as working directory object for a pathname is as 1614Specifying this object as working directory object for a pathname is as if
1393if the pathname would be specified directly, without a directory object, 1615the pathname would be specified directly, without a directory object. For
1394e.g., these calls are functionally identical: 1616example, these calls are functionally identical:
1395 1617
1396 aio_stat "somefile", sub { ... }; 1618 aio_stat "somefile", sub { ... };
1397 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1619 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1398 1620
1399=back 1621=back
1400 1622
1623To recover the path associated with an IO::AIO::WD object, you can use
1624C<aio_realpath>:
1625
1626 aio_realpath $wd, sub {
1627 warn "path is $_[0]\n";
1628 };
1629
1630Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1631sometimes, fall back to using an absolue path.
1401 1632
1402=head2 IO::AIO::REQ CLASS 1633=head2 IO::AIO::REQ CLASS
1403 1634
1404All non-aggregate C<aio_*> functions return an object of this class when 1635All non-aggregate C<aio_*> functions return an object of this class when
1405called in non-void context. 1636called in non-void context.
1583 1814
1584See C<poll_cb> for an example. 1815See C<poll_cb> for an example.
1585 1816
1586=item IO::AIO::poll_cb 1817=item IO::AIO::poll_cb
1587 1818
1588Process some outstanding events on the result pipe. You have to call 1819Process some requests that have reached the result phase (i.e. they have
1820been executed but the results are not yet reported). You have to call
1821this "regularly" to finish outstanding requests.
1822
1589this regularly. Returns C<0> if all events could be processed (or there 1823Returns C<0> if all events could be processed (or there were no
1590were no events to process), or C<-1> if it returned earlier for whatever 1824events to process), or C<-1> if it returned earlier for whatever
1591reason. Returns immediately when no events are outstanding. The amount of 1825reason. Returns immediately when no events are outstanding. The amount
1592events processed depends on the settings of C<IO::AIO::max_poll_req> and 1826of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1593C<IO::AIO::max_poll_time>. 1827C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1594 1828
1595If not all requests were processed for whatever reason, the filehandle 1829If not all requests were processed for whatever reason, the poll file
1596will still be ready when C<poll_cb> returns, so normally you don't have to 1830descriptor will still be ready when C<poll_cb> returns, so normally you
1597do anything special to have it called later. 1831don't have to do anything special to have it called later.
1598 1832
1599Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1833Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1600ready, it can be beneficial to call this function from loops which submit 1834ready, it can be beneficial to call this function from loops which submit
1601a lot of requests, to make sure the results get processed when they become 1835a lot of requests, to make sure the results get processed when they become
1602available and not just when the loop is finished and the event loop takes 1836available and not just when the loop is finished and the event loop takes
1611 poll => 'r', async => 1, 1845 poll => 'r', async => 1,
1612 cb => \&IO::AIO::poll_cb); 1846 cb => \&IO::AIO::poll_cb);
1613 1847
1614=item IO::AIO::poll_wait 1848=item IO::AIO::poll_wait
1615 1849
1616If there are any outstanding requests and none of them in the result 1850Wait until either at least one request is in the result phase or no
1617phase, wait till the result filehandle becomes ready for reading (simply 1851requests are outstanding anymore.
1618does a C<select> on the filehandle. This is useful if you want to 1852
1619synchronously wait for some requests to finish). 1853This is useful if you want to synchronously wait for some requests to
1854become ready, without actually handling them.
1620 1855
1621See C<nreqs> for an example. 1856See C<nreqs> for an example.
1622 1857
1623=item IO::AIO::poll 1858=item IO::AIO::poll
1624 1859
1745 1980
1746This is a very bad function to use in interactive programs because it 1981This is a very bad function to use in interactive programs because it
1747blocks, and a bad way to reduce concurrency because it is inexact: Better 1982blocks, and a bad way to reduce concurrency because it is inexact: Better
1748use an C<aio_group> together with a feed callback. 1983use an C<aio_group> together with a feed callback.
1749 1984
1750It's main use is in scripts without an event loop - when you want to stat 1985Its main use is in scripts without an event loop - when you want to stat
1751a lot of files, you can write somehting like this: 1986a lot of files, you can write somehting like this:
1752 1987
1753 IO::AIO::max_outstanding 32; 1988 IO::AIO::max_outstanding 32;
1754 1989
1755 for my $path (...) { 1990 for my $path (...) {
1795 2030
1796=back 2031=back
1797 2032
1798=head3 MISCELLANEOUS FUNCTIONS 2033=head3 MISCELLANEOUS FUNCTIONS
1799 2034
1800IO::AIO implements some functions that might be useful, but are not 2035IO::AIO implements some functions that are useful when you want to use
1801asynchronous. 2036some "Advanced I/O" function not available to in Perl, without going the
2037"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2038counterpart.
1802 2039
1803=over 4 2040=over 4
1804 2041
1805=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2042=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1806 2043
1825=item IO::AIO::madvise $scalar, $offset, $len, $advice 2062=item IO::AIO::madvise $scalar, $offset, $len, $advice
1826 2063
1827Simply calls the C<posix_madvise> function (see its 2064Simply calls the C<posix_madvise> function (see its
1828manpage for details). The following advice constants are 2065manpage for details). The following advice constants are
1829available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2066available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1830C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2067C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>,
2068C<IO::AIO::MADV_FREE>.
1831 2069
1832On systems that do not implement C<posix_madvise>, this function returns 2070On systems that do not implement C<posix_madvise>, this function returns
1833ENOSYS, otherwise the return value of C<posix_madvise>. 2071ENOSYS, otherwise the return value of C<posix_madvise>.
1834 2072
1835=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2073=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1843ENOSYS, otherwise the return value of C<mprotect>. 2081ENOSYS, otherwise the return value of C<mprotect>.
1844 2082
1845=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2083=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1846 2084
1847Memory-maps a file (or anonymous memory range) and attaches it to the 2085Memory-maps a file (or anonymous memory range) and attaches it to the
1848given C<$scalar>, which will act like a string scalar. 2086given C<$scalar>, which will act like a string scalar. Returns true on
2087success, and false otherwise.
1849 2088
1850The only operations allowed on the scalar are C<substr>/C<vec> that don't 2089The only operations allowed on the scalar are C<substr>/C<vec> that don't
1851change the string length, and most read-only operations such as copying it 2090change the string length, and most read-only operations such as copying it
1852or searching it with regexes and so on. 2091or searching it with regexes and so on.
1853 2092
1864filesize. 2103filesize.
1865 2104
1866C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2105C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1867C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2106C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1868 2107
1869C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2108C<$flags> can be a combination of
1870C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2109C<IO::AIO::MAP_SHARED> or
1871not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2110C<IO::AIO::MAP_PRIVATE>,
2111or a number of system-specific flags (when not available, the are C<0>):
1872(which is set to C<MAP_ANON> if your system only provides this 2112C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1873constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2113C<IO::AIO::MAP_LOCKED>,
1874C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2114C<IO::AIO::MAP_NORESERVE>,
2115C<IO::AIO::MAP_POPULATE>,
1875C<IO::AIO::MAP_NONBLOCK> 2116C<IO::AIO::MAP_NONBLOCK>,
2117C<IO::AIO::MAP_FIXED>,
2118C<IO::AIO::MAP_GROWSDOWN>,
2119C<IO::AIO::MAP_32BIT>,
2120C<IO::AIO::MAP_HUGETLB> or
2121C<IO::AIO::MAP_STACK>.
1876 2122
1877If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2123If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1878 2124
1879C<$offset> is the offset from the start of the file - it generally must be 2125C<$offset> is the offset from the start of the file - it generally must be
1880a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2126a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1905 2151
1906Calls the C<munlockall> function. 2152Calls the C<munlockall> function.
1907 2153
1908On systems that do not implement C<munlockall>, this function returns 2154On systems that do not implement C<munlockall>, this function returns
1909ENOSYS, otherwise the return value of C<munlockall>. 2155ENOSYS, otherwise the return value of C<munlockall>.
2156
2157=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2158
2159Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2160C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2161should be the file offset.
2162
2163C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2164silently corrupt the data in this case.
2165
2166The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2167C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2168C<IO::AIO::SPLICE_F_GIFT>.
2169
2170See the C<splice(2)> manpage for details.
2171
2172=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2173
2174Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2175description for C<IO::AIO::splice> above for details.
2176
2177=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2178
2179Attempts to query or change the pipe buffer size. Obviously works only
2180on pipes, and currently works only on GNU/Linux systems, and fails with
2181C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2182size on other systems, drop me a note.
2183
2184=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2185
2186This is a direct interface to the Linux L<pipe2(2)> system call. If
2187C<$flags> is missing or C<0>, then this should be the same as a call to
2188perl's built-in C<pipe> function and create a new pipe, and works on
2189systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2190(..., 4096, O_BINARY)>.
2191
2192If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2193the given flags (Linux 2.6.27, glibc 2.9).
2194
2195On success, the read and write file handles are returned.
2196
2197On error, nothing will be returned. If the pipe2 syscall is missing and
2198C<$flags> is non-zero, fails with C<ENOSYS>.
2199
2200Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2201time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2202C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1910 2203
1911=back 2204=back
1912 2205
1913=cut 2206=cut
1914 2207

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