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Revision 1.240 by root, Mon Dec 17 06:18:39 2012 UTC vs.
Revision 1.284 by root, Fri Mar 23 01:14:08 2018 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 = '4.18'; 176 our $VERSION = 4.4;
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_allocate 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
188 aio_slurp
185 aio_wd); 189 aio_wd);
186 190
187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
… …
228 aio_unlink $pathname, $callback->($status) 232 aio_unlink $pathname, $callback->($status)
229 aio_mknod $pathname, $mode, $dev, $callback->($status) 233 aio_mknod $pathname, $mode, $dev, $callback->($status)
230 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
231 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
232 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
233 aio_realpath $pathname, $callback->($link) 237 aio_realpath $pathname, $callback->($path)
234 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
235 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
236 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
237 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
238 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
243 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
244 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
245 aio_rmtree $pathname, $callback->($status) 250 aio_rmtree $pathname, $callback->($status)
251 aio_fcntl $fh, $cmd, $arg, $callback->($status)
252 aio_ioctl $fh, $request, $buf, $callback->($status)
246 aio_sync $callback->($status) 253 aio_sync $callback->($status)
247 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
248 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
249 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
250 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
251 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
252 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
253 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
254 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
255 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
256 aio_group $callback->(...) 263 aio_group $callback->(...)
257 aio_nop $callback->() 264 aio_nop $callback->()
… …
271 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
272 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
273 IO::AIO::nreqs 280 IO::AIO::nreqs
274 IO::AIO::nready 281 IO::AIO::nready
275 IO::AIO::npending 282 IO::AIO::npending
283 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
284 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
276 285
277 IO::AIO::sendfile $ofh, $ifh, $offset, $count 286 IO::AIO::sendfile $ofh, $ifh, $offset, $count
278 IO::AIO::fadvise $fh, $offset, $len, $advice 287 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 288 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar 289 IO::AIO::munmap $scalar
… …
395following POSIX and non-POSIX constants are available (missing ones on 404following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 405your system are, as usual, C<0>):
397 406
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 407C<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>, 408C<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>. 409C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
401 410
402 411
403=item aio_close $fh, $callback->($status) 412=item aio_close $fh, $callback->($status)
404 413
405Asynchronously close a file and call the callback with the result 414Asynchronously close a file and call the callback with the result
… …
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 449=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 450
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 451=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 452
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 453Reads 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<$dataoffset> 454C<$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 455calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 456error, just like the syscall).
448 457
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 458C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 459offset plus the actual number of bytes read.
451 460
… …
509As native sendfile syscalls (as practically any non-POSIX interface hacked 518As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 519together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 520on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 521in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 522so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 523fewer bytes than expected might have been transferred.
515 524
516 525
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 526=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 527
519C<aio_readahead> populates the page cache with data from a file so that 528C<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 532whole 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 533and 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 534(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. 535file. The current file offset of the file is left unchanged.
527 536
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 537If 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. 538be emulated by simply reading the data, which would have a similar effect.
530 539
531 540
532=item aio_stat $fh_or_path, $callback->($status) 541=item aio_stat $fh_or_path, $callback->($status)
533 542
534=item aio_lstat $fh, $callback->($status) 543=item aio_lstat $fh, $callback->($status)
… …
603 namemax => 255, 612 namemax => 255,
604 frsize => 1024, 613 frsize => 1024,
605 fsid => 1810 614 fsid => 1810
606 } 615 }
607 616
608Here is a (likely partial) list of fsid values used by Linux - it is safe
609to hardcode these when the $^O is C<linux>:
610
611 0x0000adf5 adfs
612 0x0000adff affs
613 0x5346414f afs
614 0x09041934 anon-inode filesystem
615 0x00000187 autofs
616 0x42465331 befs
617 0x1badface bfs
618 0x42494e4d binfmt_misc
619 0x9123683e btrfs
620 0x0027e0eb cgroupfs
621 0xff534d42 cifs
622 0x73757245 coda
623 0x012ff7b7 coh
624 0x28cd3d45 cramfs
625 0x453dcd28 cramfs-wend (wrong endianness)
626 0x64626720 debugfs
627 0x00001373 devfs
628 0x00001cd1 devpts
629 0x0000f15f ecryptfs
630 0x00414a53 efs
631 0x0000137d ext
632 0x0000ef53 ext2/ext3
633 0x0000ef51 ext2
634 0x00004006 fat
635 0x65735546 fuseblk
636 0x65735543 fusectl
637 0x0bad1dea futexfs
638 0x01161970 gfs2
639 0x47504653 gpfs
640 0x00004244 hfs
641 0xf995e849 hpfs
642 0x958458f6 hugetlbfs
643 0x2bad1dea inotifyfs
644 0x00009660 isofs
645 0x000072b6 jffs2
646 0x3153464a jfs
647 0x6b414653 k-afs
648 0x0bd00bd0 lustre
649 0x0000137f minix
650 0x0000138f minix 30 char names
651 0x00002468 minix v2
652 0x00002478 minix v2 30 char names
653 0x00004d5a minix v3
654 0x19800202 mqueue
655 0x00004d44 msdos
656 0x0000564c novell
657 0x00006969 nfs
658 0x6e667364 nfsd
659 0x00003434 nilfs
660 0x5346544e ntfs
661 0x00009fa1 openprom
662 0x7461636F ocfs2
663 0x00009fa0 proc
664 0x6165676c pstorefs
665 0x0000002f qnx4
666 0x858458f6 ramfs
667 0x52654973 reiserfs
668 0x00007275 romfs
669 0x67596969 rpc_pipefs
670 0x73636673 securityfs
671 0xf97cff8c selinux
672 0x0000517b smb
673 0x534f434b sockfs
674 0x73717368 squashfs
675 0x62656572 sysfs
676 0x012ff7b6 sysv2
677 0x012ff7b5 sysv4
678 0x01021994 tmpfs
679 0x15013346 udf
680 0x00011954 ufs
681 0x54190100 ufs byteswapped
682 0x00009fa2 usbdevfs
683 0x01021997 v9fs
684 0xa501fcf5 vxfs
685 0xabba1974 xenfs
686 0x012ff7b4 xenix
687 0x58465342 xfs
688 0x012fd16d xia
689
690=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 617=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
691 618
692Works like perl's C<utime> function (including the special case of $atime 619Works like perl's C<utime> function (including the special case of $atime
693and $mtime being undef). Fractional times are supported if the underlying 620and $mtime being undef). Fractional times are supported if the underlying
694syscalls support them. 621syscalls support them.
… …
723Works like truncate(2) or ftruncate(2). 650Works like truncate(2) or ftruncate(2).
724 651
725 652
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 653=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727 654
728Allocates or freed disk space according to the C<$mode> argument. See the 655Allocates or frees disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details. 656linux C<fallocate> documentation for details.
730 657
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 658C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
732to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | 659space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
733IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range. 660to deallocate a file range.
661
662IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
663(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
664C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
665to unshare shared blocks (see your L<fallocate(2)> manpage).
734 666
735The file system block size used by C<fallocate> is presumably the 667The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>. 668C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
669can dictate other limitations.
737 670
738If C<fallocate> isn't available or cannot be emulated (currently no 671If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 672emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740 673
741 674
… …
795=item aio_rename $srcpath, $dstpath, $callback->($status) 728=item aio_rename $srcpath, $dstpath, $callback->($status)
796 729
797Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 730Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
798rename(2) and call the callback with the result code. 731rename(2) and call the callback with the result code.
799 732
733On systems that support the AIO::WD working directory abstraction
734natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
735of failing, C<rename> is called on the absolute path of C<$wd>.
736
737
738=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
739
740Basically a version of C<aio_rename> with an additional C<$flags>
741argument. Calling this with C<$flags=0> is the same as calling
742C<aio_rename>.
743
744Non-zero flags are currently only supported on GNU/Linux systems that
745support renameat2. Other systems fail with C<ENOSYS> in this case.
746
747The following constants are available (missing ones are, as usual C<0>),
748see renameat2(2) for details:
749
750C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
751and C<IO::AIO::RENAME_WHITEOUT>.
752
800 753
801=item aio_mkdir $pathname, $mode, $callback->($status) 754=item aio_mkdir $pathname, $mode, $callback->($status)
802 755
803Asynchronously mkdir (create) a directory and call the callback with 756Asynchronously mkdir (create) a directory and call the callback with
804the result code. C<$mode> will be modified by the umask at the time the 757the result code. C<$mode> will be modified by the umask at the time the
… …
808=item aio_rmdir $pathname, $callback->($status) 761=item aio_rmdir $pathname, $callback->($status)
809 762
810Asynchronously rmdir (delete) a directory and call the callback with the 763Asynchronously rmdir (delete) a directory and call the callback with the
811result code. 764result code.
812 765
766On systems that support the AIO::WD working directory abstraction
767natively, the case C<[$wd, "."]> is specialcased - instead of failing,
768C<rmdir> is called on the absolute path of C<$wd>.
769
813 770
814=item aio_readdir $pathname, $callback->($entries) 771=item aio_readdir $pathname, $callback->($entries)
815 772
816Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 773Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
817directory (i.e. opendir + readdir + closedir). The entries will not be 774directory (i.e. opendir + readdir + closedir). The entries will not be
… …
832 789
833=over 4 790=over 4
834 791
835=item IO::AIO::READDIR_DENTS 792=item IO::AIO::READDIR_DENTS
836 793
837When this flag is off, then the callback gets an arrayref consisting of 794Normally the callback gets an arrayref consisting of names only (as
838names only (as with C<aio_readdir>), otherwise it gets an arrayref with 795with C<aio_readdir>). If this flag is set, then the callback gets an
839C<[$name, $type, $inode]> arrayrefs, each describing a single directory 796arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
840entry in more detail. 797single directory entry in more detail:
841 798
842C<$name> is the name of the entry. 799C<$name> is the name of the entry.
843 800
844C<$type> is one of the C<IO::AIO::DT_xxx> constants: 801C<$type> is one of the C<IO::AIO::DT_xxx> constants:
845 802
846C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 803C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
847C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 804C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
848C<IO::AIO::DT_WHT>. 805C<IO::AIO::DT_WHT>.
849 806
850C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 807C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
851know, you have to run stat yourself. Also, for speed reasons, the C<$type> 808to know, you have to run stat yourself. Also, for speed/memory reasons,
852scalars are read-only: you can not modify them. 809the C<$type> scalars are read-only: you must not modify them.
853 810
854C<$inode> is the inode number (which might not be exact on systems with 64 811C<$inode> is the inode number (which might not be exact on systems with 64
855bit inode numbers and 32 bit perls). This field has unspecified content on 812bit inode numbers and 32 bit perls). This field has unspecified content on
856systems that do not deliver the inode information. 813systems that do not deliver the inode information.
857 814
… …
868short names are tried first. 825short names are tried first.
869 826
870=item IO::AIO::READDIR_STAT_ORDER 827=item IO::AIO::READDIR_STAT_ORDER
871 828
872When this flag is set, then the names will be returned in an order 829When this flag is set, then the names will be returned in an order
873suitable for stat()'ing each one. That is, when you plan to stat() 830suitable for stat()'ing each one. That is, when you plan to stat() most or
874all files in the given directory, then the returned order will likely 831all files in the given directory, then the returned order will likely be
875be fastest. 832faster.
876 833
877If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 834If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
878the likely dirs come first, resulting in a less optimal stat order. 835then the likely dirs come first, resulting in a less optimal stat order
836for stat'ing all entries, but likely a more optimal order for finding
837subdirectories.
879 838
880=item IO::AIO::READDIR_FOUND_UNKNOWN 839=item IO::AIO::READDIR_FOUND_UNKNOWN
881 840
882This flag should not be set when calling C<aio_readdirx>. Instead, it 841This flag should not be set when calling C<aio_readdirx>. Instead, it
883is being set by C<aio_readdirx>, when any of the C<$type>'s found were 842is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
885C<$type>'s are known, which can be used to speed up some algorithms. 844C<$type>'s are known, which can be used to speed up some algorithms.
886 845
887=back 846=back
888 847
889 848
849=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
850
851Opens, reads and closes the given file. The data is put into C<$data>,
852which is resized as required.
853
854If C<$offset> is negative, then it is counted from the end of the file.
855
856If C<$length> is zero, then the remaining length of the file is
857used. Also, in this case, the same limitations to modifying C<$data> apply
858as when IO::AIO::mmap is used, i.e. it must only be modified in-place
859with C<substr>. If the size of the file is known, specifying a non-zero
860C<$length> results in a performance advantage.
861
862This request is similar to the older C<aio_load> request, but since it is
863a single request, it might be more efficient to use.
864
865Example: load F</etc/passwd> into C<$passwd>.
866
867 my $passwd;
868 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
869 $_[0] >= 0
870 or die "/etc/passwd: $!\n";
871
872 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
873 print $passwd;
874 };
875 IO::AIO::flush;
876
877
890=item aio_load $pathname, $data, $callback->($status) 878=item aio_load $pathname, $data, $callback->($status)
891 879
892This is a composite request that tries to fully load the given file into 880This is a composite request that tries to fully load the given file into
893memory. Status is the same as with aio_read. 881memory. Status is the same as with aio_read.
882
883Using C<aio_slurp> might be more efficient, as it is a single request.
894 884
895=cut 885=cut
896 886
897sub aio_load($$;$) { 887sub aio_load($$;$) {
898 my ($path, undef, $cb) = @_; 888 my ($path, undef, $cb) = @_;
… …
918=item aio_copy $srcpath, $dstpath, $callback->($status) 908=item aio_copy $srcpath, $dstpath, $callback->($status)
919 909
920Try to copy the I<file> (directories not supported as either source or 910Try to copy the I<file> (directories not supported as either source or
921destination) from C<$srcpath> to C<$dstpath> and call the callback with 911destination) from C<$srcpath> to C<$dstpath> and call the callback with
922a status of C<0> (ok) or C<-1> (error, see C<$!>). 912a status of C<0> (ok) or C<-1> (error, see C<$!>).
913
914Existing destination files will be truncated.
923 915
924This is a composite request that creates the destination file with 916This is a composite request that creates the destination file with
925mode 0200 and copies the contents of the source file into it using 917mode 0200 and copies the contents of the source file into it using
926C<aio_sendfile>, followed by restoring atime, mtime, access mode and 918C<aio_sendfile>, followed by restoring atime, mtime, access mode and
927uid/gid, in that order. 919uid/gid, in that order.
… …
1037Scans a directory (similar to C<aio_readdir>) but additionally tries to 1029Scans a directory (similar to C<aio_readdir>) but additionally tries to
1038efficiently separate the entries of directory C<$path> into two sets of 1030efficiently separate the entries of directory C<$path> into two sets of
1039names, directories you can recurse into (directories), and ones you cannot 1031names, directories you can recurse into (directories), and ones you cannot
1040recurse into (everything else, including symlinks to directories). 1032recurse into (everything else, including symlinks to directories).
1041 1033
1042C<aio_scandir> is a composite request that creates of many sub requests_ 1034C<aio_scandir> is a composite request that generates many sub requests.
1043C<$maxreq> specifies the maximum number of outstanding aio requests that 1035C<$maxreq> specifies the maximum number of outstanding aio requests that
1044this function generates. If it is C<< <= 0 >>, then a suitable default 1036this function generates. If it is C<< <= 0 >>, then a suitable default
1045will be chosen (currently 4). 1037will be chosen (currently 4).
1046 1038
1047On error, the callback is called without arguments, otherwise it receives 1039On error, the callback is called without arguments, otherwise it receives
… …
1213 }; 1205 };
1214 1206
1215 $grp 1207 $grp
1216} 1208}
1217 1209
1210=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1211
1212=item aio_ioctl $fh, $request, $buf, $callback->($status)
1213
1214These work just like the C<fcntl> and C<ioctl> built-in functions, except
1215they execute asynchronously and pass the return value to the callback.
1216
1217Both calls can be used for a lot of things, some of which make more sense
1218to run asynchronously in their own thread, while some others make less
1219sense. For example, calls that block waiting for external events, such
1220as locking, will also lock down an I/O thread while it is waiting, which
1221can deadlock the whole I/O system. At the same time, there might be no
1222alternative to using a thread to wait.
1223
1224So in general, you should only use these calls for things that do
1225(filesystem) I/O, not for things that wait for other events (network,
1226other processes), although if you are careful and know what you are doing,
1227you still can.
1228
1229The following constants are available (missing ones are, as usual C<0>):
1230
1231C<F_DUPFD_CLOEXEC>,
1232
1233C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1234
1235C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1236
1237C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1238C<FS_IOC_FIEMAP>.
1239
1240C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1241C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1242
1243C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1244C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1245C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1246C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1247C<FS_FL_USER_MODIFIABLE>.
1248
1249C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1250C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1251C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1252C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1253
1218=item aio_sync $callback->($status) 1254=item aio_sync $callback->($status)
1219 1255
1220Asynchronously call sync and call the callback when finished. 1256Asynchronously call sync and call the callback when finished.
1221 1257
1222=item aio_fsync $fh, $callback->($status) 1258=item aio_fsync $fh, $callback->($status)
… …
1290 }; 1326 };
1291 1327
1292 $grp 1328 $grp
1293} 1329}
1294 1330
1295=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1331=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1296 1332
1297This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1333This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1298scalars (see the C<IO::AIO::mmap> function, although it also works on data 1334scalars (see the C<IO::AIO::mmap> function, although it also works on data
1299scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1335scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1300scalar must only be modified in-place while an aio operation is pending on 1336scalar must only be modified in-place while an aio operation is pending on
… …
1302 1338
1303It calls the C<msync> function of your OS, if available, with the memory 1339It calls the C<msync> function of your OS, if available, with the memory
1304area starting at C<$offset> in the string and ending C<$length> bytes 1340area starting at C<$offset> in the string and ending C<$length> bytes
1305later. If C<$length> is negative, counts from the end, and if C<$length> 1341later. If C<$length> is negative, counts from the end, and if C<$length>
1306is C<undef>, then it goes till the end of the string. The flags can be 1342is C<undef>, then it goes till the end of the string. The flags can be
1307a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1343either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1308C<IO::AIO::MS_SYNC>. 1344C<IO::AIO::MS_INVALIDATE>.
1309 1345
1310=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1346=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1311 1347
1312This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1348This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1313scalars. 1349scalars.
… …
1396C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1432C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1397C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1433C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1398C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1434C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1399C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1435C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1400 1436
1401At the time of this writing (Linux 3.2), this requets is unreliable unless 1437At the time of this writing (Linux 3.2), this request is unreliable unless
1402C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1438C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1403it to return all extents of a range for files with large number of 1439it to return all extents of a range for files with a large number of
1404extents. The code works around all these issues if C<$count> is undef. 1440extents. The code (only) works around all these issues if C<$count> is
1441C<undef>.
1405 1442
1406=item aio_group $callback->(...) 1443=item aio_group $callback->(...)
1407 1444
1408This is a very special aio request: Instead of doing something, it is a 1445This is a very special aio request: Instead of doing something, it is a
1409container for other aio requests, which is useful if you want to bundle 1446container for other aio requests, which is useful if you want to bundle
… …
1493 aio_stat [$etcdir, "passwd"], sub { 1530 aio_stat [$etcdir, "passwd"], sub {
1494 # yay 1531 # yay
1495 }; 1532 };
1496 }; 1533 };
1497 1534
1498That C<aio_wd> is a request and not a normal function shows that creating 1535The fact that C<aio_wd> is a request and not a normal function shows that
1499an IO::AIO::WD object is itself a potentially blocking operation, which is 1536creating an IO::AIO::WD object is itself a potentially blocking operation,
1500why it is done asynchronously. 1537which is why it is done asynchronously.
1501 1538
1502To stat the directory obtained with C<aio_wd> above, one could write 1539To stat the directory obtained with C<aio_wd> above, one could write
1503either of the following three request calls: 1540either of the following three request calls:
1504 1541
1505 aio_lstat "/etc" , sub { ... # pathname as normal string 1542 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1522There are some caveats: when directories get renamed (or deleted), the 1559There are some caveats: when directories get renamed (or deleted), the
1523pathname string doesn't change, so will point to the new directory (or 1560pathname string doesn't change, so will point to the new directory (or
1524nowhere at all), while the directory fd, if available on the system, 1561nowhere at all), while the directory fd, if available on the system,
1525will still point to the original directory. Most functions accepting a 1562will still point to the original directory. Most functions accepting a
1526pathname will use the directory fd on newer systems, and the string on 1563pathname will use the directory fd on newer systems, and the string on
1527older systems. Some functions (such as realpath) will always rely on the 1564older systems. Some functions (such as C<aio_realpath>) will always rely on
1528string form of the pathname. 1565the string form of the pathname.
1529 1566
1530So this functionality is mainly useful to get some protection against 1567So this functionality is mainly useful to get some protection against
1531C<chdir>, to easily get an absolute path out of a relative path for future 1568C<chdir>, to easily get an absolute path out of a relative path for future
1532reference, and to speed up doing many operations in the same directory 1569reference, and to speed up doing many operations in the same directory
1533(e.g. when stat'ing all files in a directory). 1570(e.g. when stat'ing all files in a directory).
… …
1548passing C<undef> as working directory component of a pathname fails the 1585passing C<undef> as working directory component of a pathname fails the
1549request with C<ENOENT>, there is often no need for error checking in the 1586request with C<ENOENT>, there is often no need for error checking in the
1550C<aio_wd> callback, as future requests using the value will fail in the 1587C<aio_wd> callback, as future requests using the value will fail in the
1551expected way. 1588expected way.
1552 1589
1553If this call isn't available because your OS lacks it or it couldn't be
1554detected, it will be emulated by calling C<fsync> instead.
1555
1556=item IO::AIO::CWD 1590=item IO::AIO::CWD
1557 1591
1558This is a compiletime constant (object) that represents the process 1592This is a compiletime constant (object) that represents the process
1559current working directory. 1593current working directory.
1560 1594
… …
1572 1606
1573 aio_realpath $wd, sub { 1607 aio_realpath $wd, sub {
1574 warn "path is $_[0]\n"; 1608 warn "path is $_[0]\n";
1575 }; 1609 };
1576 1610
1611Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1612sometimes, fall back to using an absolue path.
1577 1613
1578=head2 IO::AIO::REQ CLASS 1614=head2 IO::AIO::REQ CLASS
1579 1615
1580All non-aggregate C<aio_*> functions return an object of this class when 1616All non-aggregate C<aio_*> functions return an object of this class when
1581called in non-void context. 1617called in non-void context.
… …
1925 1961
1926This is a very bad function to use in interactive programs because it 1962This is a very bad function to use in interactive programs because it
1927blocks, and a bad way to reduce concurrency because it is inexact: Better 1963blocks, and a bad way to reduce concurrency because it is inexact: Better
1928use an C<aio_group> together with a feed callback. 1964use an C<aio_group> together with a feed callback.
1929 1965
1930It's main use is in scripts without an event loop - when you want to stat 1966Its main use is in scripts without an event loop - when you want to stat
1931a lot of files, you can write somehting like this: 1967a lot of files, you can write something like this:
1932 1968
1933 IO::AIO::max_outstanding 32; 1969 IO::AIO::max_outstanding 32;
1934 1970
1935 for my $path (...) { 1971 for my $path (...) {
1936 aio_stat $path , ...; 1972 aio_stat $path , ...;
… …
1975 2011
1976=back 2012=back
1977 2013
1978=head3 MISCELLANEOUS FUNCTIONS 2014=head3 MISCELLANEOUS FUNCTIONS
1979 2015
1980IO::AIO implements some functions that might be useful, but are not 2016IO::AIO implements some functions that are useful when you want to use
1981asynchronous. 2017some "Advanced I/O" function not available to in Perl, without going the
2018"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2019counterpart.
1982 2020
1983=over 4 2021=over 4
2022
2023=item $numfd = IO::AIO::get_fdlimit
2024
2025This function is I<EXPERIMENTAL> and subject to change.
2026
2027Tries to find the current file descriptor limit and returns it, or
2028C<undef> and sets C<$!> in case of an error. The limit is one larger than
2029the highest valid file descriptor number.
2030
2031=item IO::AIO::min_fdlimit [$numfd]
2032
2033This function is I<EXPERIMENTAL> and subject to change.
2034
2035Try to increase the current file descriptor limit(s) to at least C<$numfd>
2036by changing the soft or hard file descriptor resource limit. If C<$numfd>
2037is missing, it will try to set a very high limit, although this is not
2038recommended when you know the actual minimum that you require.
2039
2040If the limit cannot be raised enough, the function makes a best-effort
2041attempt to increase the limit as much as possible, using various
2042tricks, while still failing. You can query the resulting limit using
2043C<IO::AIO::get_fdlimit>.
2044
2045If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2046true.
1984 2047
1985=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2048=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1986 2049
1987Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2050Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1988but is blocking (this makes most sense if you know the input data is 2051but is blocking (this makes most sense if you know the input data is
… …
2005=item IO::AIO::madvise $scalar, $offset, $len, $advice 2068=item IO::AIO::madvise $scalar, $offset, $len, $advice
2006 2069
2007Simply calls the C<posix_madvise> function (see its 2070Simply calls the C<posix_madvise> function (see its
2008manpage for details). The following advice constants are 2071manpage for details). The following advice constants are
2009available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2072available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2010C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2073C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2074C<IO::AIO::MADV_DONTNEED>.
2075
2076If C<$offset> is negative, counts from the end. If C<$length> is negative,
2077the remaining length of the C<$scalar> is used. If possible, C<$length>
2078will be reduced to fit into the C<$scalar>.
2011 2079
2012On systems that do not implement C<posix_madvise>, this function returns 2080On systems that do not implement C<posix_madvise>, this function returns
2013ENOSYS, otherwise the return value of C<posix_madvise>. 2081ENOSYS, otherwise the return value of C<posix_madvise>.
2014 2082
2015=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2083=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2017Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2085Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2018$scalar (see its manpage for details). The following protect 2086$scalar (see its manpage for details). The following protect
2019constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2087constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2020C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2088C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2021 2089
2090If C<$offset> is negative, counts from the end. If C<$length> is negative,
2091the remaining length of the C<$scalar> is used. If possible, C<$length>
2092will be reduced to fit into the C<$scalar>.
2093
2022On systems that do not implement C<mprotect>, this function returns 2094On systems that do not implement C<mprotect>, this function returns
2023ENOSYS, otherwise the return value of C<mprotect>. 2095ENOSYS, otherwise the return value of C<mprotect>.
2024 2096
2025=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2097=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2026 2098
2027Memory-maps a file (or anonymous memory range) and attaches it to the 2099Memory-maps a file (or anonymous memory range) and attaches it to the
2028given C<$scalar>, which will act like a string scalar. Returns true on 2100given C<$scalar>, which will act like a string scalar. Returns true on
2029success, and false otherwise. 2101success, and false otherwise.
2030 2102
2103The scalar must exist, but its contents do not matter - this means you
2104cannot use a nonexistant array or hash element. When in doubt, C<undef>
2105the scalar first.
2106
2031The only operations allowed on the scalar are C<substr>/C<vec> that don't 2107The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2032change the string length, and most read-only operations such as copying it 2108which don't change the string length, and most read-only operations such
2033or searching it with regexes and so on. 2109as copying it or searching it with regexes and so on.
2034 2110
2035Anything else is unsafe and will, at best, result in memory leaks. 2111Anything else is unsafe and will, at best, result in memory leaks.
2036 2112
2037The memory map associated with the C<$scalar> is automatically removed 2113The memory map associated with the C<$scalar> is automatically removed
2038when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2114when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2039C<IO::AIO::munmap> functions are called. 2115or C<IO::AIO::munmap> functions are called on it.
2040 2116
2041This calls the C<mmap>(2) function internally. See your system's manual 2117This calls the C<mmap>(2) function internally. See your system's manual
2042page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2118page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2043 2119
2044The C<$length> must be larger than zero and smaller than the actual 2120The C<$length> must be larger than zero and smaller than the actual
2045filesize. 2121filesize.
2046 2122
2047C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2123C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2048C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2124C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2049 2125
2050C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2126C<$flags> can be a combination of
2051C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2127C<IO::AIO::MAP_SHARED> or
2052not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2128C<IO::AIO::MAP_PRIVATE>,
2129or a number of system-specific flags (when not available, the are C<0>):
2053(which is set to C<MAP_ANON> if your system only provides this 2130C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2054constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2131C<IO::AIO::MAP_LOCKED>,
2055C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2132C<IO::AIO::MAP_NORESERVE>,
2133C<IO::AIO::MAP_POPULATE>,
2056C<IO::AIO::MAP_NONBLOCK> 2134C<IO::AIO::MAP_NONBLOCK>,
2135C<IO::AIO::MAP_FIXED>,
2136C<IO::AIO::MAP_GROWSDOWN>,
2137C<IO::AIO::MAP_32BIT>,
2138C<IO::AIO::MAP_HUGETLB> or
2139C<IO::AIO::MAP_STACK>.
2057 2140
2058If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2141If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2059 2142
2060C<$offset> is the offset from the start of the file - it generally must be 2143C<$offset> is the offset from the start of the file - it generally must be
2061a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2144a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2104 2187
2105See the C<splice(2)> manpage for details. 2188See the C<splice(2)> manpage for details.
2106 2189
2107=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2190=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2108 2191
2109Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2192Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2110description for C<IO::AIO::splice> above for details. 2193description for C<IO::AIO::splice> above for details.
2194
2195=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2196
2197Attempts to query or change the pipe buffer size. Obviously works only
2198on pipes, and currently works only on GNU/Linux systems, and fails with
2199C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2200size on other systems, drop me a note.
2201
2202=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2203
2204This is a direct interface to the Linux L<pipe2(2)> system call. If
2205C<$flags> is missing or C<0>, then this should be the same as a call to
2206perl's built-in C<pipe> function and create a new pipe, and works on
2207systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2208(..., 4096, O_BINARY)>.
2209
2210If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2211the given flags (Linux 2.6.27, glibc 2.9).
2212
2213On success, the read and write file handles are returned.
2214
2215On error, nothing will be returned. If the pipe2 syscall is missing and
2216C<$flags> is non-zero, fails with C<ENOSYS>.
2217
2218Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2219time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2220C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2221
2222Example: create a pipe race-free w.r.t. threads and fork:
2223
2224 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2225 or die "pipe2: $!\n";
2226
2227=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2228
2229This is a direct interface to the Linux L<eventfd(2)> system call. The
2230(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2231
2232On success, the new eventfd filehandle is returned, otherwise returns
2233C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2234
2235Please refer to L<eventfd(2)> for more info on this call.
2236
2237The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2238C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2239
2240Example: create a new eventfd filehandle:
2241
2242 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2243 or die "eventfd: $!\n";
2244
2245=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2246
2247This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2248(unhelpful) default for C<$flags> is C<0>.
2249
2250On success, the new timerfd filehandle is returned, otherwise returns
2251C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2252
2253Please refer to L<timerfd_create(2)> for more info on this call.
2254
2255The following C<$clockid> values are
2256available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2257C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2258C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2259C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2260
2261The following C<$flags> values are available (Linux
22622.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2263
2264Example: create a new timerfd and set it to one-second repeated alarms,
2265then wait for two alarms:
2266
2267 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2268 or die "timerfd_create: $!\n";
2269
2270 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2271 or die "timerfd_settime: $!\n";
2272
2273 for (1..2) {
2274 8 == sysread $fh, my $buf, 8
2275 or die "timerfd read failure\n";
2276
2277 printf "number of expirations (likely 1): %d\n",
2278 unpack "Q", $buf;
2279 }
2280
2281=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2282
2283This is a direct interface to the Linux L<timerfd_settime(2)> system
2284call. Please refer to its manpage for more info on this call.
2285
2286The new itimerspec is specified using two (possibly fractional) second
2287values, C<$new_interval> and C<$new_value>).
2288
2289On success, the current interval and value are returned (as per
2290C<timerfd_gettime>). On failure, the empty list is returned.
2291
2292The following C<$flags> values are
2293available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2294C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2295
2296See C<IO::AIO::timerfd_create> for a full example.
2297
2298=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2299
2300This is a direct interface to the Linux L<timerfd_gettime(2)> system
2301call. Please refer to its manpage for more info on this call.
2302
2303On success, returns the current values of interval and value for the given
2304timerfd (as potentially fractional second values). On failure, the empty
2305list is returned.
2111 2306
2112=back 2307=back
2113 2308
2114=cut 2309=cut
2115 2310
… …
2181the process will result in undefined behaviour. Calling it at any time 2376the process will result in undefined behaviour. Calling it at any time
2182will also result in any undefined (by POSIX) behaviour. 2377will also result in any undefined (by POSIX) behaviour.
2183 2378
2184=back 2379=back
2185 2380
2381=head2 LINUX-SPECIFIC CALLS
2382
2383When a call is documented as "linux-specific" then this means it
2384originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2385availability and compatibility of such calls regardless of the platform
2386it is compiled on, so platforms such as FreeBSD which often implement
2387these calls will work. When in doubt, call them and see if they fail wth
2388C<ENOSYS>.
2389
2186=head2 MEMORY USAGE 2390=head2 MEMORY USAGE
2187 2391
2188Per-request usage: 2392Per-request usage:
2189 2393
2190Each aio request uses - depending on your architecture - around 100-200 2394Each aio request uses - depending on your architecture - around 100-200
… …
2202temporary buffers, and each thread requires a stack and other data 2406temporary buffers, and each thread requires a stack and other data
2203structures (usually around 16k-128k, depending on the OS). 2407structures (usually around 16k-128k, depending on the OS).
2204 2408
2205=head1 KNOWN BUGS 2409=head1 KNOWN BUGS
2206 2410
2207Known bugs will be fixed in the next release. 2411Known bugs will be fixed in the next release :)
2412
2413=head1 KNOWN ISSUES
2414
2415Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2416or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2417non-created hash slots or other scalars I didn't think of. It's best to
2418avoid such and either use scalar variables or making sure that the scalar
2419exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2420
2421I am not sure anything can be done about this, so this is considered a
2422known issue, rather than a bug.
2208 2423
2209=head1 SEE ALSO 2424=head1 SEE ALSO
2210 2425
2211L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2426L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2212more natural syntax. 2427more natural syntax.

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