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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.231 by root, Fri Jul 27 19:03:18 2012 UTC vs.
Revision 1.275 by root, Fri Sep 22 05:20:39 2017 UTC

1=head1 NAME 1=head1 NAME
2 2
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous/Advanced Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
58not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
59files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
60aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
61using threads anyway. 61using threads anyway.
62 62
63In addition to asynchronous I/O, this module also exports some rather
64arcane interfaces, such as C<madvise> or linux's C<splice> system call,
65which is why the C<A> in C<AIO> can also mean I<advanced>.
66
63Although the module will work in the presence of other (Perl-) threads, 67Although the module will work in the presence of other (Perl-) threads,
64it is currently not reentrant in any way, so use appropriate locking 68it is currently not reentrant in any way, so use appropriate locking
65yourself, always call C<poll_cb> from within the same thread, or never 69yourself, always call C<poll_cb> from within the same thread, or never
66call C<poll_cb> (or other C<aio_> functions) recursively. 70call C<poll_cb> (or other C<aio_> functions) recursively.
67 71
68=head2 EXAMPLE 72=head2 EXAMPLE
69 73
70This is a simple example that uses the EV module and loads 74This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 75F</etc/passwd> asynchronously:
72 76
73 use Fcntl;
74 use EV; 77 use EV;
75 use IO::AIO; 78 use IO::AIO;
76 79
77 # register the IO::AIO callback with EV 80 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 81 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
95 98
96 # file contents now in $contents 99 # file contents now in $contents
97 print $contents; 100 print $contents;
98 101
99 # exit event loop and program 102 # exit event loop and program
100 EV::unloop; 103 EV::break;
101 }; 104 };
102 }; 105 };
103 106
104 # possibly queue up other requests, or open GUI windows, 107 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 108 # check for sockets etc. etc.
106 109
107 # process events as long as there are some: 110 # process events as long as there are some:
108 EV::loop; 111 EV::run;
109 112
110=head1 REQUEST ANATOMY AND LIFETIME 113=head1 REQUEST ANATOMY AND LIFETIME
111 114
112Every C<aio_*> function creates a request. which is a C data structure not 115Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 116directly visible to Perl.
168use common::sense; 171use common::sense;
169 172
170use base 'Exporter'; 173use base 'Exporter';
171 174
172BEGIN { 175BEGIN {
173 our $VERSION = '4.15'; 176 our $VERSION = 4.35;
174 177
175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close 178 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 179 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 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 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead aio_fiemap 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
180 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 184 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 187 aio_statvfs
185 aio_wd); 188 aio_wd);
228 aio_unlink $pathname, $callback->($status) 231 aio_unlink $pathname, $callback->($status)
229 aio_mknod $pathname, $mode, $dev, $callback->($status) 232 aio_mknod $pathname, $mode, $dev, $callback->($status)
230 aio_link $srcpath, $dstpath, $callback->($status) 233 aio_link $srcpath, $dstpath, $callback->($status)
231 aio_symlink $srcpath, $dstpath, $callback->($status) 234 aio_symlink $srcpath, $dstpath, $callback->($status)
232 aio_readlink $pathname, $callback->($link) 235 aio_readlink $pathname, $callback->($link)
233 aio_realpath $pathname, $callback->($link) 236 aio_realpath $pathname, $callback->($path)
234 aio_rename $srcpath, $dstpath, $callback->($status) 237 aio_rename $srcpath, $dstpath, $callback->($status)
238 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
235 aio_mkdir $pathname, $mode, $callback->($status) 239 aio_mkdir $pathname, $mode, $callback->($status)
236 aio_rmdir $pathname, $callback->($status) 240 aio_rmdir $pathname, $callback->($status)
237 aio_readdir $pathname, $callback->($entries) 241 aio_readdir $pathname, $callback->($entries)
238 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 242 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 243 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 245 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_load $pathname, $data, $callback->($status) 246 aio_load $pathname, $data, $callback->($status)
243 aio_copy $srcpath, $dstpath, $callback->($status) 247 aio_copy $srcpath, $dstpath, $callback->($status)
244 aio_move $srcpath, $dstpath, $callback->($status) 248 aio_move $srcpath, $dstpath, $callback->($status)
245 aio_rmtree $pathname, $callback->($status) 249 aio_rmtree $pathname, $callback->($status)
250 aio_fcntl $fh, $cmd, $arg, $callback->($status)
251 aio_ioctl $fh, $request, $buf, $callback->($status)
246 aio_sync $callback->($status) 252 aio_sync $callback->($status)
247 aio_syncfs $fh, $callback->($status) 253 aio_syncfs $fh, $callback->($status)
248 aio_fsync $fh, $callback->($status) 254 aio_fsync $fh, $callback->($status)
249 aio_fdatasync $fh, $callback->($status) 255 aio_fdatasync $fh, $callback->($status)
250 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 256 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
251 aio_pathsync $pathname, $callback->($status) 257 aio_pathsync $pathname, $callback->($status)
252 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 258 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
253 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
254 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 260 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
255 aio_mlockall $flags, $callback->($status) 261 aio_mlockall $flags, $callback->($status)
256 aio_group $callback->(...) 262 aio_group $callback->(...)
257 aio_nop $callback->() 263 aio_nop $callback->()
271 IO::AIO::idle_timeout $seconds 277 IO::AIO::idle_timeout $seconds
272 IO::AIO::max_outstanding $maxreqs 278 IO::AIO::max_outstanding $maxreqs
273 IO::AIO::nreqs 279 IO::AIO::nreqs
274 IO::AIO::nready 280 IO::AIO::nready
275 IO::AIO::npending 281 IO::AIO::npending
282 IO::AIO::min_fdlimit $nfd;
276 283
277 IO::AIO::sendfile $ofh, $ifh, $offset, $count 284 IO::AIO::sendfile $ofh, $ifh, $offset, $count
278 IO::AIO::fadvise $fh, $offset, $len, $advice 285 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 286 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar 287 IO::AIO::munmap $scalar
362 369
363 370
364=item aio_open $pathname, $flags, $mode, $callback->($fh) 371=item aio_open $pathname, $flags, $mode, $callback->($fh)
365 372
366Asynchronously open or create a file and call the callback with a newly 373Asynchronously open or create a file and call the callback with a newly
367created filehandle for the file. 374created filehandle for the file (or C<undef> in case of an error).
368 375
369The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 376The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
370for an explanation. 377for an explanation.
371 378
372The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 379The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
395following POSIX and non-POSIX constants are available (missing ones on 402following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 403your system are, as usual, C<0>):
397 404
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 405C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
399C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 406C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
400C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 407C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
401 408
402 409
403=item aio_close $fh, $callback->($status) 410=item aio_close $fh, $callback->($status)
404 411
405Asynchronously close a file and call the callback with the result 412Asynchronously close a file and call the callback with the result
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 447=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 448
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 449=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 450
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 451Reads or writes C<$length> bytes from or to the specified C<$fh> and
445C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 452C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
446and calls the callback without the actual number of bytes read (or -1 on 453calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 454error, just like the syscall).
448 455
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 456C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 457offset plus the actual number of bytes read.
451 458
509As native sendfile syscalls (as practically any non-POSIX interface hacked 516As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 517together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 518on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 519in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 520so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 521fewer bytes than expected might have been transferred.
515 522
516 523
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 524=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 525
519C<aio_readahead> populates the page cache with data from a file so that 526C<aio_readahead> populates the page cache with data from a file so that
523whole pages, so that offset is effectively rounded down to a page boundary 530whole pages, so that offset is effectively rounded down to a page boundary
524and bytes are read up to the next page boundary greater than or equal to 531and bytes are read up to the next page boundary greater than or equal to
525(off-set+length). C<aio_readahead> does not read beyond the end of the 532(off-set+length). C<aio_readahead> does not read beyond the end of the
526file. The current file offset of the file is left unchanged. 533file. The current file offset of the file is left unchanged.
527 534
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 535If that syscall doesn't exist (likely if your kernel isn't Linux) it will
529emulated by simply reading the data, which would have a similar effect. 536be emulated by simply reading the data, which would have a similar effect.
530 537
531 538
532=item aio_stat $fh_or_path, $callback->($status) 539=item aio_stat $fh_or_path, $callback->($status)
533 540
534=item aio_lstat $fh, $callback->($status) 541=item aio_lstat $fh, $callback->($status)
603 namemax => 255, 610 namemax => 255,
604 frsize => 1024, 611 frsize => 1024,
605 fsid => 1810 612 fsid => 1810
606 } 613 }
607 614
615Here is a (likely partial - send me updates!) list of fsid values used by
616Linux - it is safe to hardcode these when C<$^O> is C<linux>:
617
618 0x0000adf5 adfs
619 0x0000adff affs
620 0x5346414f afs
621 0x09041934 anon-inode filesystem
622 0x00000187 autofs
623 0x42465331 befs
624 0x1badface bfs
625 0x42494e4d binfmt_misc
626 0x9123683e btrfs
627 0x0027e0eb cgroupfs
628 0xff534d42 cifs
629 0x73757245 coda
630 0x012ff7b7 coh
631 0x28cd3d45 cramfs
632 0x453dcd28 cramfs-wend (wrong endianness)
633 0x64626720 debugfs
634 0x00001373 devfs
635 0x00001cd1 devpts
636 0x0000f15f ecryptfs
637 0x00414a53 efs
638 0x0000137d ext
639 0x0000ef53 ext2/ext3/ext4
640 0x0000ef51 ext2
641 0xf2f52010 f2fs
642 0x00004006 fat
643 0x65735546 fuseblk
644 0x65735543 fusectl
645 0x0bad1dea futexfs
646 0x01161970 gfs2
647 0x47504653 gpfs
648 0x00004244 hfs
649 0xf995e849 hpfs
650 0x00c0ffee hostfs
651 0x958458f6 hugetlbfs
652 0x2bad1dea inotifyfs
653 0x00009660 isofs
654 0x000072b6 jffs2
655 0x3153464a jfs
656 0x6b414653 k-afs
657 0x0bd00bd0 lustre
658 0x0000137f minix
659 0x0000138f minix 30 char names
660 0x00002468 minix v2
661 0x00002478 minix v2 30 char names
662 0x00004d5a minix v3
663 0x19800202 mqueue
664 0x00004d44 msdos
665 0x0000564c novell
666 0x00006969 nfs
667 0x6e667364 nfsd
668 0x00003434 nilfs
669 0x5346544e ntfs
670 0x00009fa1 openprom
671 0x7461636F ocfs2
672 0x00009fa0 proc
673 0x6165676c pstorefs
674 0x0000002f qnx4
675 0x68191122 qnx6
676 0x858458f6 ramfs
677 0x52654973 reiserfs
678 0x00007275 romfs
679 0x67596969 rpc_pipefs
680 0x73636673 securityfs
681 0xf97cff8c selinux
682 0x0000517b smb
683 0x534f434b sockfs
684 0x73717368 squashfs
685 0x62656572 sysfs
686 0x012ff7b6 sysv2
687 0x012ff7b5 sysv4
688 0x01021994 tmpfs
689 0x15013346 udf
690 0x00011954 ufs
691 0x54190100 ufs byteswapped
692 0x00009fa2 usbdevfs
693 0x01021997 v9fs
694 0xa501fcf5 vxfs
695 0xabba1974 xenfs
696 0x012ff7b4 xenix
697 0x58465342 xfs
698 0x012fd16d xia
608 699
609=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 700=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
610 701
611Works like perl's C<utime> function (including the special case of $atime 702Works like perl's C<utime> function (including the special case of $atime
612and $mtime being undef). Fractional times are supported if the underlying 703and $mtime being undef). Fractional times are supported if the underlying
642Works like truncate(2) or ftruncate(2). 733Works like truncate(2) or ftruncate(2).
643 734
644 735
645=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 736=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
646 737
647Allocates or freed disk space according to the C<$mode> argument. See the 738Allocates or frees disk space according to the C<$mode> argument. See the
648linux C<fallocate> docuemntation for details. 739linux C<fallocate> documentation for details.
649 740
650C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 741C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
651to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | 742space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
652IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range. 743to deallocate a file range.
744
745IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
746(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
747C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
748to unshare shared blocks (see your L<fallocate(2)> manpage).
653 749
654The file system block size used by C<fallocate> is presumably the 750The file system block size used by C<fallocate> is presumably the
655C<f_bsize> returned by C<statvfs>. 751C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
752can dictate other limitations.
656 753
657If C<fallocate> isn't available or cannot be emulated (currently no 754If C<fallocate> isn't available or cannot be emulated (currently no
658emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 755emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
659 756
660 757
702 799
703 800
704=item aio_realpath $pathname, $callback->($path) 801=item aio_realpath $pathname, $callback->($path)
705 802
706Asynchronously make the path absolute and resolve any symlinks in 803Asynchronously make the path absolute and resolve any symlinks in
707C<$path>. The resulting path only consists of directories (Same as 804C<$path>. The resulting path only consists of directories (same as
708L<Cwd::realpath>). 805L<Cwd::realpath>).
709 806
710This request can be used to get the absolute path of the current working 807This request can be used to get the absolute path of the current working
711directory by passing it a path of F<.> (a single dot). 808directory by passing it a path of F<.> (a single dot).
712 809
713 810
714=item aio_rename $srcpath, $dstpath, $callback->($status) 811=item aio_rename $srcpath, $dstpath, $callback->($status)
715 812
716Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 813Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
717rename(2) and call the callback with the result code. 814rename(2) and call the callback with the result code.
815
816On systems that support the AIO::WD working directory abstraction
817natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
818of failing, C<rename> is called on the absolute path of C<$wd>.
819
820
821=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
822
823Basically a version of C<aio_rename> with an additional C<$flags>
824argument. Calling this with C<$flags=0> is the same as calling
825C<aio_rename>.
826
827Non-zero flags are currently only supported on GNU/Linux systems that
828support renameat2. Other systems fail with C<ENOSYS> in this case.
829
830The following constants are available (missing ones are, as usual C<0>),
831see renameat2(2) for details:
832
833C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
834and C<IO::AIO::RENAME_WHITEOUT>.
718 835
719 836
720=item aio_mkdir $pathname, $mode, $callback->($status) 837=item aio_mkdir $pathname, $mode, $callback->($status)
721 838
722Asynchronously mkdir (create) a directory and call the callback with 839Asynchronously mkdir (create) a directory and call the callback with
726 843
727=item aio_rmdir $pathname, $callback->($status) 844=item aio_rmdir $pathname, $callback->($status)
728 845
729Asynchronously rmdir (delete) a directory and call the callback with the 846Asynchronously rmdir (delete) a directory and call the callback with the
730result code. 847result code.
848
849On systems that support the AIO::WD working directory abstraction
850natively, the case C<[$wd, "."]> is specialcased - instead of failing,
851C<rmdir> is called on the absolute path of C<$wd>.
731 852
732 853
733=item aio_readdir $pathname, $callback->($entries) 854=item aio_readdir $pathname, $callback->($entries)
734 855
735Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 856Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
837=item aio_copy $srcpath, $dstpath, $callback->($status) 958=item aio_copy $srcpath, $dstpath, $callback->($status)
838 959
839Try to copy the I<file> (directories not supported as either source or 960Try to copy the I<file> (directories not supported as either source or
840destination) from C<$srcpath> to C<$dstpath> and call the callback with 961destination) from C<$srcpath> to C<$dstpath> and call the callback with
841a status of C<0> (ok) or C<-1> (error, see C<$!>). 962a status of C<0> (ok) or C<-1> (error, see C<$!>).
963
964Existing destination files will be truncated.
842 965
843This is a composite request that creates the destination file with 966This is a composite request that creates the destination file with
844mode 0200 and copies the contents of the source file into it using 967mode 0200 and copies the contents of the source file into it using
845C<aio_sendfile>, followed by restoring atime, mtime, access mode and 968C<aio_sendfile>, followed by restoring atime, mtime, access mode and
846uid/gid, in that order. 969uid/gid, in that order.
1100} 1223}
1101 1224
1102=item aio_rmtree $pathname, $callback->($status) 1225=item aio_rmtree $pathname, $callback->($status)
1103 1226
1104Delete a directory tree starting (and including) C<$path>, return the 1227Delete a directory tree starting (and including) C<$path>, return the
1105status of the final C<rmdir> only. This is a composite request that 1228status of the final C<rmdir> only. This is a composite request that
1106uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1229uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1107everything else. 1230everything else.
1108 1231
1109=cut 1232=cut
1110 1233
1131 add $grp $dirgrp; 1254 add $grp $dirgrp;
1132 }; 1255 };
1133 1256
1134 $grp 1257 $grp
1135} 1258}
1259
1260=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1261
1262=item aio_ioctl $fh, $request, $buf, $callback->($status)
1263
1264These work just like the C<fcntl> and C<ioctl> built-in functions, except
1265they execute asynchronously and pass the return value to the callback.
1266
1267Both calls can be used for a lot of things, some of which make more sense
1268to run asynchronously in their own thread, while some others make less
1269sense. For example, calls that block waiting for external events, such
1270as locking, will also lock down an I/O thread while it is waiting, which
1271can deadlock the whole I/O system. At the same time, there might be no
1272alternative to using a thread to wait.
1273
1274So in general, you should only use these calls for things that do
1275(filesystem) I/O, not for things that wait for other events (network,
1276other processes), although if you are careful and know what you are doing,
1277you still can.
1278
1279The following constants are available (missing ones are, as usual C<0>):
1280
1281C<F_DUPFD_CLOEXEC>,
1282
1283C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1284
1285C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1286
1287C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1288C<FS_IOC_FIEMAP>.
1289
1290C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1291C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1292
1293C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1294C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1295C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1296C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1297C<FS_FL_USER_MODIFIABLE>.
1298
1299C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1300C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1301C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1302C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1136 1303
1137=item aio_sync $callback->($status) 1304=item aio_sync $callback->($status)
1138 1305
1139Asynchronously call sync and call the callback when finished. 1306Asynchronously call sync and call the callback when finished.
1140 1307
1209 }; 1376 };
1210 1377
1211 $grp 1378 $grp
1212} 1379}
1213 1380
1214=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1381=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1215 1382
1216This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1383This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1217scalars (see the C<IO::AIO::mmap> function, although it also works on data 1384scalars (see the C<IO::AIO::mmap> function, although it also works on data
1218scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1385scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1219scalar must only be modified in-place while an aio operation is pending on 1386scalar must only be modified in-place while an aio operation is pending on
1221 1388
1222It calls the C<msync> function of your OS, if available, with the memory 1389It calls the C<msync> function of your OS, if available, with the memory
1223area starting at C<$offset> in the string and ending C<$length> bytes 1390area starting at C<$offset> in the string and ending C<$length> bytes
1224later. If C<$length> is negative, counts from the end, and if C<$length> 1391later. If C<$length> is negative, counts from the end, and if C<$length>
1225is C<undef>, then it goes till the end of the string. The flags can be 1392is C<undef>, then it goes till the end of the string. The flags can be
1226a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1393either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1227C<IO::AIO::MS_SYNC>. 1394C<IO::AIO::MS_INVALIDATE>.
1228 1395
1229=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1396=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1230 1397
1231This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1398This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1232scalars. 1399scalars.
1233 1400
1234It touches (reads or writes) all memory pages in the specified 1401It touches (reads or writes) all memory pages in the specified
1235range inside the scalar. All caveats and parameters are the same 1402range inside the scalar. All caveats and parameters are the same
1236as for C<aio_msync>, above, except for flags, which must be either 1403as for C<aio_msync>, above, except for flags, which must be either
1237C<0> (which reads all pages and ensures they are instantiated) or 1404C<0> (which reads all pages and ensures they are instantiated) or
1238C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1405C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1239writing an octet from it, which dirties the page). 1406writing an octet from it, which dirties the page).
1240 1407
1241=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1408=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1242 1409
1243This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1410This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1277 1444
1278 aio_mlockall IO::AIO::MCL_FUTURE; 1445 aio_mlockall IO::AIO::MCL_FUTURE;
1279 1446
1280=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) 1447=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1281 1448
1282Queries the extents of the given file (by calling the Linux FIEMAP ioctl, 1449Queries the extents of the given file (by calling the Linux C<FIEMAP>
1283see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the 1450ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1284C<ioctl> is not available on your OS, then this request will fail with 1451the ioctl is not available on your OS, then this request will fail with
1285C<ENOSYS>. 1452C<ENOSYS>.
1286 1453
1287C<$start> is the starting offset to query extents for, C<$length> is the 1454C<$start> is the starting offset to query extents for, C<$length> is the
1288size of the range to query - if it is C<undef>, then the whole file will 1455size of the range to query - if it is C<undef>, then the whole file will
1289be queried. 1456be queried.
1292C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also 1459C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1293exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query 1460exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1294the data portion. 1461the data portion.
1295 1462
1296C<$count> is the maximum number of extent records to return. If it is 1463C<$count> is the maximum number of extent records to return. If it is
1297C<undef>, then IO::AIO queries all extents of the file. As a very special 1464C<undef>, then IO::AIO queries all extents of the range. As a very special
1298case, if it is C<0>, then the callback receives the number of extents 1465case, if it is C<0>, then the callback receives the number of extents
1299instead of the extents themselves. 1466instead of the extents themselves (which is unreliable, see below).
1300 1467
1301If an error occurs, the callback receives no arguments. The special 1468If an error occurs, the callback receives no arguments. The special
1302C<errno> value C<IO::AIO::EBADR> is available to test for flag errors. 1469C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1303 1470
1304Otherwise, the callback receives an array reference with extent 1471Otherwise, the callback receives an array reference with extent
1315C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1482C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1316C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1483C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1317C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1484C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1318C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1485C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1319 1486
1487At the time of this writing (Linux 3.2), this requets is unreliable unless
1488C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1489it to return all extents of a range for files with large number of
1490extents. The code works around all these issues if C<$count> is undef.
1491
1320=item aio_group $callback->(...) 1492=item aio_group $callback->(...)
1321 1493
1322This is a very special aio request: Instead of doing something, it is a 1494This is a very special aio request: Instead of doing something, it is a
1323container for other aio requests, which is useful if you want to bundle 1495container for other aio requests, which is useful if you want to bundle
1324many requests into a single, composite, request with a definite callback 1496many requests into a single, composite, request with a definite callback
1407 aio_stat [$etcdir, "passwd"], sub { 1579 aio_stat [$etcdir, "passwd"], sub {
1408 # yay 1580 # yay
1409 }; 1581 };
1410 }; 1582 };
1411 1583
1412That C<aio_wd> is a request and not a normal function shows that creating 1584The fact that C<aio_wd> is a request and not a normal function shows that
1413an IO::AIO::WD object is itself a potentially blocking operation, which is 1585creating an IO::AIO::WD object is itself a potentially blocking operation,
1414why it is done asynchronously. 1586which is why it is done asynchronously.
1415 1587
1416To stat the directory obtained with C<aio_wd> above, one could write 1588To stat the directory obtained with C<aio_wd> above, one could write
1417either of the following three request calls: 1589either of the following three request calls:
1418 1590
1419 aio_lstat "/etc" , sub { ... # pathname as normal string 1591 aio_lstat "/etc" , sub { ... # pathname as normal string
1439will still point to the original directory. Most functions accepting a 1611will still point to the original directory. Most functions accepting a
1440pathname will use the directory fd on newer systems, and the string on 1612pathname will use the directory fd on newer systems, and the string on
1441older systems. Some functions (such as realpath) will always rely on the 1613older systems. Some functions (such as realpath) will always rely on the
1442string form of the pathname. 1614string form of the pathname.
1443 1615
1444So this fucntionality is mainly useful to get some protection against 1616So this functionality is mainly useful to get some protection against
1445C<chdir>, to easily get an absolute path out of a relative path for future 1617C<chdir>, to easily get an absolute path out of a relative path for future
1446reference, and to speed up doing many operations in the same directory 1618reference, and to speed up doing many operations in the same directory
1447(e.g. when stat'ing all files in a directory). 1619(e.g. when stat'ing all files in a directory).
1448 1620
1449The following functions implement this working directory abstraction: 1621The following functions implement this working directory abstraction:
1462passing C<undef> as working directory component of a pathname fails the 1634passing C<undef> as working directory component of a pathname fails the
1463request with C<ENOENT>, there is often no need for error checking in the 1635request with C<ENOENT>, there is often no need for error checking in the
1464C<aio_wd> callback, as future requests using the value will fail in the 1636C<aio_wd> callback, as future requests using the value will fail in the
1465expected way. 1637expected way.
1466 1638
1467If this call isn't available because your OS lacks it or it couldn't be
1468detected, it will be emulated by calling C<fsync> instead.
1469
1470=item IO::AIO::CWD 1639=item IO::AIO::CWD
1471 1640
1472This is a compiletime constant (object) that represents the process 1641This is a compiletime constant (object) that represents the process
1473current working directory. 1642current working directory.
1474 1643
1475Specifying this object as working directory object for a pathname is as 1644Specifying this object as working directory object for a pathname is as if
1476if the pathname would be specified directly, without a directory object, 1645the pathname would be specified directly, without a directory object. For
1477e.g., these calls are functionally identical: 1646example, these calls are functionally identical:
1478 1647
1479 aio_stat "somefile", sub { ... }; 1648 aio_stat "somefile", sub { ... };
1480 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1649 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1481 1650
1482=back 1651=back
1483 1652
1653To recover the path associated with an IO::AIO::WD object, you can use
1654C<aio_realpath>:
1655
1656 aio_realpath $wd, sub {
1657 warn "path is $_[0]\n";
1658 };
1659
1660Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1661sometimes, fall back to using an absolue path.
1484 1662
1485=head2 IO::AIO::REQ CLASS 1663=head2 IO::AIO::REQ CLASS
1486 1664
1487All non-aggregate C<aio_*> functions return an object of this class when 1665All non-aggregate C<aio_*> functions return an object of this class when
1488called in non-void context. 1666called in non-void context.
1666 1844
1667See C<poll_cb> for an example. 1845See C<poll_cb> for an example.
1668 1846
1669=item IO::AIO::poll_cb 1847=item IO::AIO::poll_cb
1670 1848
1671Process some outstanding events on the result pipe. You have to call 1849Process some requests that have reached the result phase (i.e. they have
1850been executed but the results are not yet reported). You have to call
1851this "regularly" to finish outstanding requests.
1852
1672this regularly. Returns C<0> if all events could be processed (or there 1853Returns C<0> if all events could be processed (or there were no
1673were no events to process), or C<-1> if it returned earlier for whatever 1854events to process), or C<-1> if it returned earlier for whatever
1674reason. Returns immediately when no events are outstanding. The amount of 1855reason. Returns immediately when no events are outstanding. The amount
1675events processed depends on the settings of C<IO::AIO::max_poll_req> and 1856of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1676C<IO::AIO::max_poll_time>. 1857C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1677 1858
1678If not all requests were processed for whatever reason, the filehandle 1859If not all requests were processed for whatever reason, the poll file
1679will still be ready when C<poll_cb> returns, so normally you don't have to 1860descriptor will still be ready when C<poll_cb> returns, so normally you
1680do anything special to have it called later. 1861don't have to do anything special to have it called later.
1681 1862
1682Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1863Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1683ready, it can be beneficial to call this function from loops which submit 1864ready, it can be beneficial to call this function from loops which submit
1684a lot of requests, to make sure the results get processed when they become 1865a lot of requests, to make sure the results get processed when they become
1685available and not just when the loop is finished and the event loop takes 1866available and not just when the loop is finished and the event loop takes
1694 poll => 'r', async => 1, 1875 poll => 'r', async => 1,
1695 cb => \&IO::AIO::poll_cb); 1876 cb => \&IO::AIO::poll_cb);
1696 1877
1697=item IO::AIO::poll_wait 1878=item IO::AIO::poll_wait
1698 1879
1699If there are any outstanding requests and none of them in the result 1880Wait until either at least one request is in the result phase or no
1700phase, wait till the result filehandle becomes ready for reading (simply 1881requests are outstanding anymore.
1701does a C<select> on the filehandle. This is useful if you want to 1882
1702synchronously wait for some requests to finish). 1883This is useful if you want to synchronously wait for some requests to
1884become ready, without actually handling them.
1703 1885
1704See C<nreqs> for an example. 1886See C<nreqs> for an example.
1705 1887
1706=item IO::AIO::poll 1888=item IO::AIO::poll
1707 1889
1828 2010
1829This is a very bad function to use in interactive programs because it 2011This is a very bad function to use in interactive programs because it
1830blocks, and a bad way to reduce concurrency because it is inexact: Better 2012blocks, and a bad way to reduce concurrency because it is inexact: Better
1831use an C<aio_group> together with a feed callback. 2013use an C<aio_group> together with a feed callback.
1832 2014
1833It's main use is in scripts without an event loop - when you want to stat 2015Its main use is in scripts without an event loop - when you want to stat
1834a lot of files, you can write somehting like this: 2016a lot of files, you can write something like this:
1835 2017
1836 IO::AIO::max_outstanding 32; 2018 IO::AIO::max_outstanding 32;
1837 2019
1838 for my $path (...) { 2020 for my $path (...) {
1839 aio_stat $path , ...; 2021 aio_stat $path , ...;
1878 2060
1879=back 2061=back
1880 2062
1881=head3 MISCELLANEOUS FUNCTIONS 2063=head3 MISCELLANEOUS FUNCTIONS
1882 2064
1883IO::AIO implements some functions that might be useful, but are not 2065IO::AIO implements some functions that are useful when you want to use
1884asynchronous. 2066some "Advanced I/O" function not available to in Perl, without going the
2067"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2068counterpart.
1885 2069
1886=over 4 2070=over 4
2071
2072=item $numfd = IO::AIO::get_fdlimit
2073
2074Tries to find the current file descriptor limit and returns it, or
2075C<undef> and sets C<$!> in case of an error. The limit is one larger than
2076the highest valid file descriptor number.
2077
2078=item IO::AIO::min_fdlimit [$numfd]
2079
2080Try to increase the current file descriptor limit(s) to at least C<$numfd>
2081by changing the soft or hard file descriptor resource limit. If C<$numfd>
2082is missing, it will try to set a very high limit, although this is not
2083recommended when you know the actual minimum that you require.
2084
2085If the limit cannot be raised enough, the function makes a best-effort
2086attempt to increase the limit as much as possible, using various
2087tricks, while still failing. You can query the resulting limit using
2088C<IO::AIO::get_fdlimit>.
2089
2090If an error occurs, returns C<undef> and sets C<$!>.
1887 2091
1888=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2092=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1889 2093
1890Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2094Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1891but is blocking (this makes most sense if you know the input data is 2095but is blocking (this makes most sense if you know the input data is
1908=item IO::AIO::madvise $scalar, $offset, $len, $advice 2112=item IO::AIO::madvise $scalar, $offset, $len, $advice
1909 2113
1910Simply calls the C<posix_madvise> function (see its 2114Simply calls the C<posix_madvise> function (see its
1911manpage for details). The following advice constants are 2115manpage for details). The following advice constants are
1912available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2116available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1913C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2117C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2118C<IO::AIO::MADV_DONTNEED>.
2119
2120If C<$offset> is negative, counts from the end. If C<$length> is negative,
2121the remaining length of the C<$scalar> is used. If possible, C<$length>
2122will be reduced to fit into the C<$scalar>.
1914 2123
1915On systems that do not implement C<posix_madvise>, this function returns 2124On systems that do not implement C<posix_madvise>, this function returns
1916ENOSYS, otherwise the return value of C<posix_madvise>. 2125ENOSYS, otherwise the return value of C<posix_madvise>.
1917 2126
1918=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2127=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1920Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2129Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1921$scalar (see its manpage for details). The following protect 2130$scalar (see its manpage for details). The following protect
1922constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2131constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1923C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2132C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1924 2133
2134If C<$offset> is negative, counts from the end. If C<$length> is negative,
2135the remaining length of the C<$scalar> is used. If possible, C<$length>
2136will be reduced to fit into the C<$scalar>.
2137
1925On systems that do not implement C<mprotect>, this function returns 2138On systems that do not implement C<mprotect>, this function returns
1926ENOSYS, otherwise the return value of C<mprotect>. 2139ENOSYS, otherwise the return value of C<mprotect>.
1927 2140
1928=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2141=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1929 2142
1930Memory-maps a file (or anonymous memory range) and attaches it to the 2143Memory-maps a file (or anonymous memory range) and attaches it to the
1931given C<$scalar>, which will act like a string scalar. Returns true on 2144given C<$scalar>, which will act like a string scalar. Returns true on
1932success, and false otherwise. 2145success, and false otherwise.
1933 2146
2147The scalar must exist, but its contents do not matter - this means you
2148cannot use a nonexistant array or hash element. When in doubt, C<undef>
2149the scalar first.
2150
1934The only operations allowed on the scalar are C<substr>/C<vec> that don't 2151The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1935change the string length, and most read-only operations such as copying it 2152which don't change the string length, and most read-only operations such
1936or searching it with regexes and so on. 2153as copying it or searching it with regexes and so on.
1937 2154
1938Anything else is unsafe and will, at best, result in memory leaks. 2155Anything else is unsafe and will, at best, result in memory leaks.
1939 2156
1940The memory map associated with the C<$scalar> is automatically removed 2157The memory map associated with the C<$scalar> is automatically removed
1941when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2158when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1942C<IO::AIO::munmap> functions are called. 2159or C<IO::AIO::munmap> functions are called on it.
1943 2160
1944This calls the C<mmap>(2) function internally. See your system's manual 2161This calls the C<mmap>(2) function internally. See your system's manual
1945page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2162page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1946 2163
1947The C<$length> must be larger than zero and smaller than the actual 2164The C<$length> must be larger than zero and smaller than the actual
1948filesize. 2165filesize.
1949 2166
1950C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2167C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1951C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2168C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1952 2169
1953C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2170C<$flags> can be a combination of
1954C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2171C<IO::AIO::MAP_SHARED> or
1955not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2172C<IO::AIO::MAP_PRIVATE>,
2173or a number of system-specific flags (when not available, the are C<0>):
1956(which is set to C<MAP_ANON> if your system only provides this 2174C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1957constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2175C<IO::AIO::MAP_LOCKED>,
1958C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2176C<IO::AIO::MAP_NORESERVE>,
2177C<IO::AIO::MAP_POPULATE>,
1959C<IO::AIO::MAP_NONBLOCK> 2178C<IO::AIO::MAP_NONBLOCK>,
2179C<IO::AIO::MAP_FIXED>,
2180C<IO::AIO::MAP_GROWSDOWN>,
2181C<IO::AIO::MAP_32BIT>,
2182C<IO::AIO::MAP_HUGETLB> or
2183C<IO::AIO::MAP_STACK>.
1960 2184
1961If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2185If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1962 2186
1963C<$offset> is the offset from the start of the file - it generally must be 2187C<$offset> is the offset from the start of the file - it generally must be
1964a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2188a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
2007 2231
2008See the C<splice(2)> manpage for details. 2232See the C<splice(2)> manpage for details.
2009 2233
2010=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2234=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2011 2235
2012Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2236Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2013description for C<IO::AIO::splice> above for details. 2237description for C<IO::AIO::splice> above for details.
2238
2239=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2240
2241Attempts to query or change the pipe buffer size. Obviously works only
2242on pipes, and currently works only on GNU/Linux systems, and fails with
2243C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2244size on other systems, drop me a note.
2245
2246=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2247
2248This is a direct interface to the Linux L<pipe2(2)> system call. If
2249C<$flags> is missing or C<0>, then this should be the same as a call to
2250perl's built-in C<pipe> function and create a new pipe, and works on
2251systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2252(..., 4096, O_BINARY)>.
2253
2254If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2255the given flags (Linux 2.6.27, glibc 2.9).
2256
2257On success, the read and write file handles are returned.
2258
2259On error, nothing will be returned. If the pipe2 syscall is missing and
2260C<$flags> is non-zero, fails with C<ENOSYS>.
2261
2262Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2263time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2264C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2014 2265
2015=back 2266=back
2016 2267
2017=cut 2268=cut
2018 2269

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