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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 1.278 by root, Sun Oct 1 07:24:34 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 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
283 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
276 284
277 IO::AIO::sendfile $ofh, $ifh, $offset, $count 285 IO::AIO::sendfile $ofh, $ifh, $offset, $count
278 IO::AIO::fadvise $fh, $offset, $len, $advice 286 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 287 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar 288 IO::AIO::munmap $scalar
362 370
363 371
364=item aio_open $pathname, $flags, $mode, $callback->($fh) 372=item aio_open $pathname, $flags, $mode, $callback->($fh)
365 373
366Asynchronously open or create a file and call the callback with a newly 374Asynchronously open or create a file and call the callback with a newly
367created filehandle for the file. 375created filehandle for the file (or C<undef> in case of an error).
368 376
369The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 377The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
370for an explanation. 378for an explanation.
371 379
372The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 380The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
395following POSIX and non-POSIX constants are available (missing ones on 403following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 404your system are, as usual, C<0>):
397 405
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 406C<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>, 407C<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>. 408C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
401 409
402 410
403=item aio_close $fh, $callback->($status) 411=item aio_close $fh, $callback->($status)
404 412
405Asynchronously close a file and call the callback with the result 413Asynchronously close a file and call the callback with the result
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 448=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 449
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 450=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 451
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 452Reads 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<$dataoffset> 453C<$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 454calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 455error, just like the syscall).
448 456
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 457C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 458offset plus the actual number of bytes read.
451 459
509As native sendfile syscalls (as practically any non-POSIX interface hacked 517As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 518together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 519on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 520in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 521so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 522fewer bytes than expected might have been transferred.
515 523
516 524
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 525=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 526
519C<aio_readahead> populates the page cache with data from a file so that 527C<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 531whole 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 532and 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 533(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. 534file. The current file offset of the file is left unchanged.
527 535
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 536If 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. 537be emulated by simply reading the data, which would have a similar effect.
530 538
531 539
532=item aio_stat $fh_or_path, $callback->($status) 540=item aio_stat $fh_or_path, $callback->($status)
533 541
534=item aio_lstat $fh, $callback->($status) 542=item aio_lstat $fh, $callback->($status)
603 namemax => 255, 611 namemax => 255,
604 frsize => 1024, 612 frsize => 1024,
605 fsid => 1810 613 fsid => 1810
606 } 614 }
607 615
616Here is a (likely partial - send me updates!) list of fsid values used by
617Linux - it is safe to hardcode these when C<$^O> is C<linux>:
618
619 0x0000adf5 adfs
620 0x0000adff affs
621 0x5346414f afs
622 0x09041934 anon-inode filesystem
623 0x00000187 autofs
624 0x42465331 befs
625 0x1badface bfs
626 0x42494e4d binfmt_misc
627 0x9123683e btrfs
628 0x0027e0eb cgroupfs
629 0xff534d42 cifs
630 0x73757245 coda
631 0x012ff7b7 coh
632 0x28cd3d45 cramfs
633 0x453dcd28 cramfs-wend (wrong endianness)
634 0x64626720 debugfs
635 0x00001373 devfs
636 0x00001cd1 devpts
637 0x0000f15f ecryptfs
638 0x00414a53 efs
639 0x0000137d ext
640 0x0000ef53 ext2/ext3/ext4
641 0x0000ef51 ext2
642 0xf2f52010 f2fs
643 0x00004006 fat
644 0x65735546 fuseblk
645 0x65735543 fusectl
646 0x0bad1dea futexfs
647 0x01161970 gfs2
648 0x47504653 gpfs
649 0x00004244 hfs
650 0xf995e849 hpfs
651 0x00c0ffee hostfs
652 0x958458f6 hugetlbfs
653 0x2bad1dea inotifyfs
654 0x00009660 isofs
655 0x000072b6 jffs2
656 0x3153464a jfs
657 0x6b414653 k-afs
658 0x0bd00bd0 lustre
659 0x0000137f minix
660 0x0000138f minix 30 char names
661 0x00002468 minix v2
662 0x00002478 minix v2 30 char names
663 0x00004d5a minix v3
664 0x19800202 mqueue
665 0x00004d44 msdos
666 0x0000564c novell
667 0x00006969 nfs
668 0x6e667364 nfsd
669 0x00003434 nilfs
670 0x5346544e ntfs
671 0x00009fa1 openprom
672 0x7461636F ocfs2
673 0x00009fa0 proc
674 0x6165676c pstorefs
675 0x0000002f qnx4
676 0x68191122 qnx6
677 0x858458f6 ramfs
678 0x52654973 reiserfs
679 0x00007275 romfs
680 0x67596969 rpc_pipefs
681 0x73636673 securityfs
682 0xf97cff8c selinux
683 0x0000517b smb
684 0x534f434b sockfs
685 0x73717368 squashfs
686 0x62656572 sysfs
687 0x012ff7b6 sysv2
688 0x012ff7b5 sysv4
689 0x01021994 tmpfs
690 0x15013346 udf
691 0x00011954 ufs
692 0x54190100 ufs byteswapped
693 0x00009fa2 usbdevfs
694 0x01021997 v9fs
695 0xa501fcf5 vxfs
696 0xabba1974 xenfs
697 0x012ff7b4 xenix
698 0x58465342 xfs
699 0x012fd16d xia
608 700
609=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 701=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
610 702
611Works like perl's C<utime> function (including the special case of $atime 703Works like perl's C<utime> function (including the special case of $atime
612and $mtime being undef). Fractional times are supported if the underlying 704and $mtime being undef). Fractional times are supported if the underlying
642Works like truncate(2) or ftruncate(2). 734Works like truncate(2) or ftruncate(2).
643 735
644 736
645=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 737=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
646 738
647Allocates or freed disk space according to the C<$mode> argument. See the 739Allocates or frees disk space according to the C<$mode> argument. See the
648linux C<fallocate> docuemntation for details. 740linux C<fallocate> documentation for details.
649 741
650C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 742C<$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 | 743space, 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. 744to deallocate a file range.
745
746IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
747(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
748C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
749to unshare shared blocks (see your L<fallocate(2)> manpage).
653 750
654The file system block size used by C<fallocate> is presumably the 751The file system block size used by C<fallocate> is presumably the
655C<f_bsize> returned by C<statvfs>. 752C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
753can dictate other limitations.
656 754
657If C<fallocate> isn't available or cannot be emulated (currently no 755If C<fallocate> isn't available or cannot be emulated (currently no
658emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 756emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
659 757
660 758
702 800
703 801
704=item aio_realpath $pathname, $callback->($path) 802=item aio_realpath $pathname, $callback->($path)
705 803
706Asynchronously make the path absolute and resolve any symlinks in 804Asynchronously make the path absolute and resolve any symlinks in
707C<$path>. The resulting path only consists of directories (Same as 805C<$path>. The resulting path only consists of directories (same as
708L<Cwd::realpath>). 806L<Cwd::realpath>).
709 807
710This request can be used to get the absolute path of the current working 808This request can be used to get the absolute path of the current working
711directory by passing it a path of F<.> (a single dot). 809directory by passing it a path of F<.> (a single dot).
712 810
713 811
714=item aio_rename $srcpath, $dstpath, $callback->($status) 812=item aio_rename $srcpath, $dstpath, $callback->($status)
715 813
716Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 814Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
717rename(2) and call the callback with the result code. 815rename(2) and call the callback with the result code.
816
817On systems that support the AIO::WD working directory abstraction
818natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
819of failing, C<rename> is called on the absolute path of C<$wd>.
820
821
822=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
823
824Basically a version of C<aio_rename> with an additional C<$flags>
825argument. Calling this with C<$flags=0> is the same as calling
826C<aio_rename>.
827
828Non-zero flags are currently only supported on GNU/Linux systems that
829support renameat2. Other systems fail with C<ENOSYS> in this case.
830
831The following constants are available (missing ones are, as usual C<0>),
832see renameat2(2) for details:
833
834C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
835and C<IO::AIO::RENAME_WHITEOUT>.
718 836
719 837
720=item aio_mkdir $pathname, $mode, $callback->($status) 838=item aio_mkdir $pathname, $mode, $callback->($status)
721 839
722Asynchronously mkdir (create) a directory and call the callback with 840Asynchronously mkdir (create) a directory and call the callback with
726 844
727=item aio_rmdir $pathname, $callback->($status) 845=item aio_rmdir $pathname, $callback->($status)
728 846
729Asynchronously rmdir (delete) a directory and call the callback with the 847Asynchronously rmdir (delete) a directory and call the callback with the
730result code. 848result code.
849
850On systems that support the AIO::WD working directory abstraction
851natively, the case C<[$wd, "."]> is specialcased - instead of failing,
852C<rmdir> is called on the absolute path of C<$wd>.
731 853
732 854
733=item aio_readdir $pathname, $callback->($entries) 855=item aio_readdir $pathname, $callback->($entries)
734 856
735Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 857Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
837=item aio_copy $srcpath, $dstpath, $callback->($status) 959=item aio_copy $srcpath, $dstpath, $callback->($status)
838 960
839Try to copy the I<file> (directories not supported as either source or 961Try to copy the I<file> (directories not supported as either source or
840destination) from C<$srcpath> to C<$dstpath> and call the callback with 962destination) from C<$srcpath> to C<$dstpath> and call the callback with
841a status of C<0> (ok) or C<-1> (error, see C<$!>). 963a status of C<0> (ok) or C<-1> (error, see C<$!>).
964
965Existing destination files will be truncated.
842 966
843This is a composite request that creates the destination file with 967This is a composite request that creates the destination file with
844mode 0200 and copies the contents of the source file into it using 968mode 0200 and copies the contents of the source file into it using
845C<aio_sendfile>, followed by restoring atime, mtime, access mode and 969C<aio_sendfile>, followed by restoring atime, mtime, access mode and
846uid/gid, in that order. 970uid/gid, in that order.
956Scans a directory (similar to C<aio_readdir>) but additionally tries to 1080Scans a directory (similar to C<aio_readdir>) but additionally tries to
957efficiently separate the entries of directory C<$path> into two sets of 1081efficiently separate the entries of directory C<$path> into two sets of
958names, directories you can recurse into (directories), and ones you cannot 1082names, directories you can recurse into (directories), and ones you cannot
959recurse into (everything else, including symlinks to directories). 1083recurse into (everything else, including symlinks to directories).
960 1084
961C<aio_scandir> is a composite request that creates of many sub requests_ 1085C<aio_scandir> is a composite request that generates many sub requests.
962C<$maxreq> specifies the maximum number of outstanding aio requests that 1086C<$maxreq> specifies the maximum number of outstanding aio requests that
963this function generates. If it is C<< <= 0 >>, then a suitable default 1087this function generates. If it is C<< <= 0 >>, then a suitable default
964will be chosen (currently 4). 1088will be chosen (currently 4).
965 1089
966On error, the callback is called without arguments, otherwise it receives 1090On error, the callback is called without arguments, otherwise it receives
1100} 1224}
1101 1225
1102=item aio_rmtree $pathname, $callback->($status) 1226=item aio_rmtree $pathname, $callback->($status)
1103 1227
1104Delete a directory tree starting (and including) C<$path>, return the 1228Delete a directory tree starting (and including) C<$path>, return the
1105status of the final C<rmdir> only. This is a composite request that 1229status of the final C<rmdir> only. This is a composite request that
1106uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1230uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1107everything else. 1231everything else.
1108 1232
1109=cut 1233=cut
1110 1234
1131 add $grp $dirgrp; 1255 add $grp $dirgrp;
1132 }; 1256 };
1133 1257
1134 $grp 1258 $grp
1135} 1259}
1260
1261=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1262
1263=item aio_ioctl $fh, $request, $buf, $callback->($status)
1264
1265These work just like the C<fcntl> and C<ioctl> built-in functions, except
1266they execute asynchronously and pass the return value to the callback.
1267
1268Both calls can be used for a lot of things, some of which make more sense
1269to run asynchronously in their own thread, while some others make less
1270sense. For example, calls that block waiting for external events, such
1271as locking, will also lock down an I/O thread while it is waiting, which
1272can deadlock the whole I/O system. At the same time, there might be no
1273alternative to using a thread to wait.
1274
1275So in general, you should only use these calls for things that do
1276(filesystem) I/O, not for things that wait for other events (network,
1277other processes), although if you are careful and know what you are doing,
1278you still can.
1279
1280The following constants are available (missing ones are, as usual C<0>):
1281
1282C<F_DUPFD_CLOEXEC>,
1283
1284C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1285
1286C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1287
1288C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1289C<FS_IOC_FIEMAP>.
1290
1291C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1292C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1293
1294C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1295C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1296C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1297C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1298C<FS_FL_USER_MODIFIABLE>.
1299
1300C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1301C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1302C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1303C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1136 1304
1137=item aio_sync $callback->($status) 1305=item aio_sync $callback->($status)
1138 1306
1139Asynchronously call sync and call the callback when finished. 1307Asynchronously call sync and call the callback when finished.
1140 1308
1209 }; 1377 };
1210 1378
1211 $grp 1379 $grp
1212} 1380}
1213 1381
1214=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1382=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1215 1383
1216This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1384This 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 1385scalars (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 1386scalars 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 1387scalar must only be modified in-place while an aio operation is pending on
1221 1389
1222It calls the C<msync> function of your OS, if available, with the memory 1390It 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 1391area 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> 1392later. 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 1393is 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 1394either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1227C<IO::AIO::MS_SYNC>. 1395C<IO::AIO::MS_INVALIDATE>.
1228 1396
1229=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1397=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1230 1398
1231This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1399This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1232scalars. 1400scalars.
1233 1401
1234It touches (reads or writes) all memory pages in the specified 1402It touches (reads or writes) all memory pages in the specified
1235range inside the scalar. All caveats and parameters are the same 1403range inside the scalar. All caveats and parameters are the same
1236as for C<aio_msync>, above, except for flags, which must be either 1404as for C<aio_msync>, above, except for flags, which must be either
1237C<0> (which reads all pages and ensures they are instantiated) or 1405C<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 1406C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1239writing an octet from it, which dirties the page). 1407writing an octet from it, which dirties the page).
1240 1408
1241=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1409=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1242 1410
1243This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1411This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1277 1445
1278 aio_mlockall IO::AIO::MCL_FUTURE; 1446 aio_mlockall IO::AIO::MCL_FUTURE;
1279 1447
1280=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) 1448=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1281 1449
1282Queries the extents of the given file (by calling the Linux FIEMAP ioctl, 1450Queries the extents of the given file (by calling the Linux C<FIEMAP>
1283see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the 1451ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1284C<ioctl> is not available on your OS, then this request will fail with 1452the ioctl is not available on your OS, then this request will fail with
1285C<ENOSYS>. 1453C<ENOSYS>.
1286 1454
1287C<$start> is the starting offset to query extents for, C<$length> is the 1455C<$start> is the starting offset to query extents for, C<$length> is the
1288size of the range to query - if it is C<undef>, then the whole file will 1456size of the range to query - if it is C<undef>, then the whole file will
1289be queried. 1457be queried.
1292C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also 1460C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1293exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query 1461exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1294the data portion. 1462the data portion.
1295 1463
1296C<$count> is the maximum number of extent records to return. If it is 1464C<$count> is the maximum number of extent records to return. If it is
1297C<undef>, then IO::AIO queries all extents of the file. As a very special 1465C<undef>, then IO::AIO queries all extents of the range. As a very special
1298case, if it is C<0>, then the callback receives the number of extents 1466case, if it is C<0>, then the callback receives the number of extents
1299instead of the extents themselves. 1467instead of the extents themselves (which is unreliable, see below).
1300 1468
1301If an error occurs, the callback receives no arguments. The special 1469If an error occurs, the callback receives no arguments. The special
1302C<errno> value C<IO::AIO::EBADR> is available to test for flag errors. 1470C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1303 1471
1304Otherwise, the callback receives an array reference with extent 1472Otherwise, the callback receives an array reference with extent
1315C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1483C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1316C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1484C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1317C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1485C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1318C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1486C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1319 1487
1488At the time of this writing (Linux 3.2), this request is unreliable unless
1489C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1490it to return all extents of a range for files with a large number of
1491extents. The code (only) works around all these issues if C<$count> is
1492C<undef>.
1493
1320=item aio_group $callback->(...) 1494=item aio_group $callback->(...)
1321 1495
1322This is a very special aio request: Instead of doing something, it is a 1496This is a very special aio request: Instead of doing something, it is a
1323container for other aio requests, which is useful if you want to bundle 1497container for other aio requests, which is useful if you want to bundle
1324many requests into a single, composite, request with a definite callback 1498many requests into a single, composite, request with a definite callback
1407 aio_stat [$etcdir, "passwd"], sub { 1581 aio_stat [$etcdir, "passwd"], sub {
1408 # yay 1582 # yay
1409 }; 1583 };
1410 }; 1584 };
1411 1585
1412That C<aio_wd> is a request and not a normal function shows that creating 1586The 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 1587creating an IO::AIO::WD object is itself a potentially blocking operation,
1414why it is done asynchronously. 1588which is why it is done asynchronously.
1415 1589
1416To stat the directory obtained with C<aio_wd> above, one could write 1590To stat the directory obtained with C<aio_wd> above, one could write
1417either of the following three request calls: 1591either of the following three request calls:
1418 1592
1419 aio_lstat "/etc" , sub { ... # pathname as normal string 1593 aio_lstat "/etc" , sub { ... # pathname as normal string
1436There are some caveats: when directories get renamed (or deleted), the 1610There are some caveats: when directories get renamed (or deleted), the
1437pathname string doesn't change, so will point to the new directory (or 1611pathname string doesn't change, so will point to the new directory (or
1438nowhere at all), while the directory fd, if available on the system, 1612nowhere at all), while the directory fd, if available on the system,
1439will still point to the original directory. Most functions accepting a 1613will still point to the original directory. Most functions accepting a
1440pathname will use the directory fd on newer systems, and the string on 1614pathname will use the directory fd on newer systems, and the string on
1441older systems. Some functions (such as realpath) will always rely on the 1615older systems. Some functions (such as C<aio_realpath>) will always rely on
1442string form of the pathname. 1616the string form of the pathname.
1443 1617
1444So this fucntionality is mainly useful to get some protection against 1618So 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 1619C<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 1620reference, and to speed up doing many operations in the same directory
1447(e.g. when stat'ing all files in a directory). 1621(e.g. when stat'ing all files in a directory).
1448 1622
1449The following functions implement this working directory abstraction: 1623The following functions implement this working directory abstraction:
1462passing C<undef> as working directory component of a pathname fails the 1636passing 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 1637request 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 1638C<aio_wd> callback, as future requests using the value will fail in the
1465expected way. 1639expected way.
1466 1640
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 1641=item IO::AIO::CWD
1471 1642
1472This is a compiletime constant (object) that represents the process 1643This is a compiletime constant (object) that represents the process
1473current working directory. 1644current working directory.
1474 1645
1475Specifying this object as working directory object for a pathname is as 1646Specifying this object as working directory object for a pathname is as if
1476if the pathname would be specified directly, without a directory object, 1647the pathname would be specified directly, without a directory object. For
1477e.g., these calls are functionally identical: 1648example, these calls are functionally identical:
1478 1649
1479 aio_stat "somefile", sub { ... }; 1650 aio_stat "somefile", sub { ... };
1480 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1651 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1481 1652
1482=back 1653=back
1483 1654
1655To recover the path associated with an IO::AIO::WD object, you can use
1656C<aio_realpath>:
1657
1658 aio_realpath $wd, sub {
1659 warn "path is $_[0]\n";
1660 };
1661
1662Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1663sometimes, fall back to using an absolue path.
1484 1664
1485=head2 IO::AIO::REQ CLASS 1665=head2 IO::AIO::REQ CLASS
1486 1666
1487All non-aggregate C<aio_*> functions return an object of this class when 1667All non-aggregate C<aio_*> functions return an object of this class when
1488called in non-void context. 1668called in non-void context.
1666 1846
1667See C<poll_cb> for an example. 1847See C<poll_cb> for an example.
1668 1848
1669=item IO::AIO::poll_cb 1849=item IO::AIO::poll_cb
1670 1850
1671Process some outstanding events on the result pipe. You have to call 1851Process some requests that have reached the result phase (i.e. they have
1852been executed but the results are not yet reported). You have to call
1853this "regularly" to finish outstanding requests.
1854
1672this regularly. Returns C<0> if all events could be processed (or there 1855Returns 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 1856events to process), or C<-1> if it returned earlier for whatever
1674reason. Returns immediately when no events are outstanding. The amount of 1857reason. Returns immediately when no events are outstanding. The amount
1675events processed depends on the settings of C<IO::AIO::max_poll_req> and 1858of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1676C<IO::AIO::max_poll_time>. 1859C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1677 1860
1678If not all requests were processed for whatever reason, the filehandle 1861If 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 1862descriptor will still be ready when C<poll_cb> returns, so normally you
1680do anything special to have it called later. 1863don't have to do anything special to have it called later.
1681 1864
1682Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1865Apart 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 1866ready, 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 1867a 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 1868available and not just when the loop is finished and the event loop takes
1694 poll => 'r', async => 1, 1877 poll => 'r', async => 1,
1695 cb => \&IO::AIO::poll_cb); 1878 cb => \&IO::AIO::poll_cb);
1696 1879
1697=item IO::AIO::poll_wait 1880=item IO::AIO::poll_wait
1698 1881
1699If there are any outstanding requests and none of them in the result 1882Wait until either at least one request is in the result phase or no
1700phase, wait till the result filehandle becomes ready for reading (simply 1883requests are outstanding anymore.
1701does a C<select> on the filehandle. This is useful if you want to 1884
1702synchronously wait for some requests to finish). 1885This is useful if you want to synchronously wait for some requests to
1886become ready, without actually handling them.
1703 1887
1704See C<nreqs> for an example. 1888See C<nreqs> for an example.
1705 1889
1706=item IO::AIO::poll 1890=item IO::AIO::poll
1707 1891
1828 2012
1829This is a very bad function to use in interactive programs because it 2013This 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 2014blocks, and a bad way to reduce concurrency because it is inexact: Better
1831use an C<aio_group> together with a feed callback. 2015use an C<aio_group> together with a feed callback.
1832 2016
1833It's main use is in scripts without an event loop - when you want to stat 2017Its main use is in scripts without an event loop - when you want to stat
1834a lot of files, you can write somehting like this: 2018a lot of files, you can write something like this:
1835 2019
1836 IO::AIO::max_outstanding 32; 2020 IO::AIO::max_outstanding 32;
1837 2021
1838 for my $path (...) { 2022 for my $path (...) {
1839 aio_stat $path , ...; 2023 aio_stat $path , ...;
1878 2062
1879=back 2063=back
1880 2064
1881=head3 MISCELLANEOUS FUNCTIONS 2065=head3 MISCELLANEOUS FUNCTIONS
1882 2066
1883IO::AIO implements some functions that might be useful, but are not 2067IO::AIO implements some functions that are useful when you want to use
1884asynchronous. 2068some "Advanced I/O" function not available to in Perl, without going the
2069"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2070counterpart.
1885 2071
1886=over 4 2072=over 4
2073
2074=item $numfd = IO::AIO::get_fdlimit
2075
2076This function is I<EXPERIMENTAL> and subject to change.
2077
2078Tries to find the current file descriptor limit and returns it, or
2079C<undef> and sets C<$!> in case of an error. The limit is one larger than
2080the highest valid file descriptor number.
2081
2082=item IO::AIO::min_fdlimit [$numfd]
2083
2084This function is I<EXPERIMENTAL> and subject to change.
2085
2086Try to increase the current file descriptor limit(s) to at least C<$numfd>
2087by changing the soft or hard file descriptor resource limit. If C<$numfd>
2088is missing, it will try to set a very high limit, although this is not
2089recommended when you know the actual minimum that you require.
2090
2091If the limit cannot be raised enough, the function makes a best-effort
2092attempt to increase the limit as much as possible, using various
2093tricks, while still failing. You can query the resulting limit using
2094C<IO::AIO::get_fdlimit>.
2095
2096If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2097true.
1887 2098
1888=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2099=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1889 2100
1890Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2101Calls 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 2102but is blocking (this makes most sense if you know the input data is
1908=item IO::AIO::madvise $scalar, $offset, $len, $advice 2119=item IO::AIO::madvise $scalar, $offset, $len, $advice
1909 2120
1910Simply calls the C<posix_madvise> function (see its 2121Simply calls the C<posix_madvise> function (see its
1911manpage for details). The following advice constants are 2122manpage for details). The following advice constants are
1912available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2123available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1913C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2124C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2125C<IO::AIO::MADV_DONTNEED>.
2126
2127If C<$offset> is negative, counts from the end. If C<$length> is negative,
2128the remaining length of the C<$scalar> is used. If possible, C<$length>
2129will be reduced to fit into the C<$scalar>.
1914 2130
1915On systems that do not implement C<posix_madvise>, this function returns 2131On systems that do not implement C<posix_madvise>, this function returns
1916ENOSYS, otherwise the return value of C<posix_madvise>. 2132ENOSYS, otherwise the return value of C<posix_madvise>.
1917 2133
1918=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2134=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1920Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2136Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1921$scalar (see its manpage for details). The following protect 2137$scalar (see its manpage for details). The following protect
1922constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2138constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1923C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2139C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1924 2140
2141If C<$offset> is negative, counts from the end. If C<$length> is negative,
2142the remaining length of the C<$scalar> is used. If possible, C<$length>
2143will be reduced to fit into the C<$scalar>.
2144
1925On systems that do not implement C<mprotect>, this function returns 2145On systems that do not implement C<mprotect>, this function returns
1926ENOSYS, otherwise the return value of C<mprotect>. 2146ENOSYS, otherwise the return value of C<mprotect>.
1927 2147
1928=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2148=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1929 2149
1930Memory-maps a file (or anonymous memory range) and attaches it to the 2150Memory-maps a file (or anonymous memory range) and attaches it to the
1931given C<$scalar>, which will act like a string scalar. Returns true on 2151given C<$scalar>, which will act like a string scalar. Returns true on
1932success, and false otherwise. 2152success, and false otherwise.
1933 2153
2154The scalar must exist, but its contents do not matter - this means you
2155cannot use a nonexistant array or hash element. When in doubt, C<undef>
2156the scalar first.
2157
1934The only operations allowed on the scalar are C<substr>/C<vec> that don't 2158The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1935change the string length, and most read-only operations such as copying it 2159which don't change the string length, and most read-only operations such
1936or searching it with regexes and so on. 2160as copying it or searching it with regexes and so on.
1937 2161
1938Anything else is unsafe and will, at best, result in memory leaks. 2162Anything else is unsafe and will, at best, result in memory leaks.
1939 2163
1940The memory map associated with the C<$scalar> is automatically removed 2164The memory map associated with the C<$scalar> is automatically removed
1941when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2165when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1942C<IO::AIO::munmap> functions are called. 2166or C<IO::AIO::munmap> functions are called on it.
1943 2167
1944This calls the C<mmap>(2) function internally. See your system's manual 2168This calls the C<mmap>(2) function internally. See your system's manual
1945page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2169page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1946 2170
1947The C<$length> must be larger than zero and smaller than the actual 2171The C<$length> must be larger than zero and smaller than the actual
1948filesize. 2172filesize.
1949 2173
1950C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2174C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1951C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2175C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1952 2176
1953C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2177C<$flags> can be a combination of
1954C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2178C<IO::AIO::MAP_SHARED> or
1955not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2179C<IO::AIO::MAP_PRIVATE>,
2180or a number of system-specific flags (when not available, the are C<0>):
1956(which is set to C<MAP_ANON> if your system only provides this 2181C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1957constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2182C<IO::AIO::MAP_LOCKED>,
1958C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2183C<IO::AIO::MAP_NORESERVE>,
2184C<IO::AIO::MAP_POPULATE>,
1959C<IO::AIO::MAP_NONBLOCK> 2185C<IO::AIO::MAP_NONBLOCK>,
2186C<IO::AIO::MAP_FIXED>,
2187C<IO::AIO::MAP_GROWSDOWN>,
2188C<IO::AIO::MAP_32BIT>,
2189C<IO::AIO::MAP_HUGETLB> or
2190C<IO::AIO::MAP_STACK>.
1960 2191
1961If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2192If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1962 2193
1963C<$offset> is the offset from the start of the file - it generally must be 2194C<$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>. 2195a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
2007 2238
2008See the C<splice(2)> manpage for details. 2239See the C<splice(2)> manpage for details.
2009 2240
2010=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2241=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2011 2242
2012Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2243Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2013description for C<IO::AIO::splice> above for details. 2244description for C<IO::AIO::splice> above for details.
2245
2246=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2247
2248Attempts to query or change the pipe buffer size. Obviously works only
2249on pipes, and currently works only on GNU/Linux systems, and fails with
2250C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2251size on other systems, drop me a note.
2252
2253=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2254
2255This is a direct interface to the Linux L<pipe2(2)> system call. If
2256C<$flags> is missing or C<0>, then this should be the same as a call to
2257perl's built-in C<pipe> function and create a new pipe, and works on
2258systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2259(..., 4096, O_BINARY)>.
2260
2261If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2262the given flags (Linux 2.6.27, glibc 2.9).
2263
2264On success, the read and write file handles are returned.
2265
2266On error, nothing will be returned. If the pipe2 syscall is missing and
2267C<$flags> is non-zero, fails with C<ENOSYS>.
2268
2269Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2270time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2271C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2014 2272
2015=back 2273=back
2016 2274
2017=cut 2275=cut
2018 2276

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