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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.242 by root, Sun Jan 6 11:48:13 2013 UTC vs.
Revision 1.292 by root, Tue Aug 14 09:29:50 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 = '4.19'; 176 our $VERSION = 4.53;
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
190 nreqs nready npending nthreads 194 nreqs nready npending nthreads
191 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
192 sendfile fadvise madvise 196 sendfile fadvise madvise
193 mmap munmap munlock munlockall); 197 mmap munmap mremap munlock munlockall);
194 198
195 push @AIO_REQ, qw(aio_busy); # not exported 199 push @AIO_REQ, qw(aio_busy); # not exported
196 200
197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
198 202
… …
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
290 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
281 IO::AIO::madvise $scalar, $offset, $length, $advice 291 IO::AIO::madvise $scalar, $offset, $length, $advice
282 IO::AIO::mprotect $scalar, $offset, $length, $protect 292 IO::AIO::mprotect $scalar, $offset, $length, $protect
283 IO::AIO::munlock $scalar, $offset = 0, $length = undef 293 IO::AIO::munlock $scalar, $offset = 0, $length = undef
284 IO::AIO::munlockall 294 IO::AIO::munlockall
285 295
… …
395following POSIX and non-POSIX constants are available (missing ones on 405following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 406your system are, as usual, C<0>):
397 407
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 408C<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>, 409C<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>. 410C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
401 411
402 412
403=item aio_close $fh, $callback->($status) 413=item aio_close $fh, $callback->($status)
404 414
405Asynchronously close a file and call the callback with the result 415Asynchronously close a file and call the callback with the result
… …
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 450=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 451
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 452=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 453
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 454Reads 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<$dataoffset> 455C<$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 456calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 457error, just like the syscall).
448 458
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 459C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 460offset plus the actual number of bytes read.
451 461
… …
509As native sendfile syscalls (as practically any non-POSIX interface hacked 519As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 520together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 521on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 522in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 523so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 524fewer bytes than expected might have been transferred.
515 525
516 526
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 527=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 528
519C<aio_readahead> populates the page cache with data from a file so that 529C<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 533whole 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 534and 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 535(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. 536file. The current file offset of the file is left unchanged.
527 537
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 538If 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. 539be emulated by simply reading the data, which would have a similar effect.
530 540
531 541
532=item aio_stat $fh_or_path, $callback->($status) 542=item aio_stat $fh_or_path, $callback->($status)
533 543
534=item aio_lstat $fh, $callback->($status) 544=item aio_lstat $fh, $callback->($status)
… …
550behaviour). 560behaviour).
551 561
552C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 562C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
553C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, 563C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
554C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. 564C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
565
566To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
567ACCESS>.
555 568
556Example: Print the length of F</etc/passwd>: 569Example: Print the length of F</etc/passwd>:
557 570
558 aio_stat "/etc/passwd", sub { 571 aio_stat "/etc/passwd", sub {
559 $_[0] and die "stat failed: $!"; 572 $_[0] and die "stat failed: $!";
… …
603 namemax => 255, 616 namemax => 255,
604 frsize => 1024, 617 frsize => 1024,
605 fsid => 1810 618 fsid => 1810
606 } 619 }
607 620
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) 621=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
691 622
692Works like perl's C<utime> function (including the special case of $atime 623Works like perl's C<utime> function (including the special case of $atime
693and $mtime being undef). Fractional times are supported if the underlying 624and $mtime being undef). Fractional times are supported if the underlying
694syscalls support them. 625syscalls support them.
… …
723Works like truncate(2) or ftruncate(2). 654Works like truncate(2) or ftruncate(2).
724 655
725 656
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 657=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727 658
728Allocates or freed disk space according to the C<$mode> argument. See the 659Allocates or frees disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details. 660linux C<fallocate> documentation for details.
730 661
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 662C<$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 | 663space, 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. 664to deallocate a file range.
665
666IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
667(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
668C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
669to unshare shared blocks (see your L<fallocate(2)> manpage).
734 670
735The file system block size used by C<fallocate> is presumably the 671The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>. 672C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
673can dictate other limitations.
737 674
738If C<fallocate> isn't available or cannot be emulated (currently no 675If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 676emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740 677
741 678
… …
800On systems that support the AIO::WD working directory abstraction 737On systems that support the AIO::WD working directory abstraction
801natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 738natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
802of failing, C<rename> is called on the absolute path of C<$wd>. 739of failing, C<rename> is called on the absolute path of C<$wd>.
803 740
804 741
742=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
743
744Basically a version of C<aio_rename> with an additional C<$flags>
745argument. Calling this with C<$flags=0> is the same as calling
746C<aio_rename>.
747
748Non-zero flags are currently only supported on GNU/Linux systems that
749support renameat2. Other systems fail with C<ENOSYS> in this case.
750
751The following constants are available (missing ones are, as usual C<0>),
752see renameat2(2) for details:
753
754C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
755and C<IO::AIO::RENAME_WHITEOUT>.
756
757
805=item aio_mkdir $pathname, $mode, $callback->($status) 758=item aio_mkdir $pathname, $mode, $callback->($status)
806 759
807Asynchronously mkdir (create) a directory and call the callback with 760Asynchronously mkdir (create) a directory and call the callback with
808the result code. C<$mode> will be modified by the umask at the time the 761the result code. C<$mode> will be modified by the umask at the time the
809request is executed, so do not change your umask. 762request is executed, so do not change your umask.
… …
840 793
841=over 4 794=over 4
842 795
843=item IO::AIO::READDIR_DENTS 796=item IO::AIO::READDIR_DENTS
844 797
845When this flag is off, then the callback gets an arrayref consisting of 798Normally the callback gets an arrayref consisting of names only (as
846names only (as with C<aio_readdir>), otherwise it gets an arrayref with 799with C<aio_readdir>). If this flag is set, then the callback gets an
847C<[$name, $type, $inode]> arrayrefs, each describing a single directory 800arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
848entry in more detail. 801single directory entry in more detail:
849 802
850C<$name> is the name of the entry. 803C<$name> is the name of the entry.
851 804
852C<$type> is one of the C<IO::AIO::DT_xxx> constants: 805C<$type> is one of the C<IO::AIO::DT_xxx> constants:
853 806
854C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 807C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
855C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 808C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
856C<IO::AIO::DT_WHT>. 809C<IO::AIO::DT_WHT>.
857 810
858C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 811C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
859know, you have to run stat yourself. Also, for speed reasons, the C<$type> 812to know, you have to run stat yourself. Also, for speed/memory reasons,
860scalars are read-only: you can not modify them. 813the C<$type> scalars are read-only: you must not modify them.
861 814
862C<$inode> is the inode number (which might not be exact on systems with 64 815C<$inode> is the inode number (which might not be exact on systems with 64
863bit inode numbers and 32 bit perls). This field has unspecified content on 816bit inode numbers and 32 bit perls). This field has unspecified content on
864systems that do not deliver the inode information. 817systems that do not deliver the inode information.
865 818
… …
876short names are tried first. 829short names are tried first.
877 830
878=item IO::AIO::READDIR_STAT_ORDER 831=item IO::AIO::READDIR_STAT_ORDER
879 832
880When this flag is set, then the names will be returned in an order 833When this flag is set, then the names will be returned in an order
881suitable for stat()'ing each one. That is, when you plan to stat() 834suitable for stat()'ing each one. That is, when you plan to stat() most or
882all files in the given directory, then the returned order will likely 835all files in the given directory, then the returned order will likely be
883be fastest. 836faster.
884 837
885If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 838If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
886the likely dirs come first, resulting in a less optimal stat order. 839then the likely dirs come first, resulting in a less optimal stat order
840for stat'ing all entries, but likely a more optimal order for finding
841subdirectories.
887 842
888=item IO::AIO::READDIR_FOUND_UNKNOWN 843=item IO::AIO::READDIR_FOUND_UNKNOWN
889 844
890This flag should not be set when calling C<aio_readdirx>. Instead, it 845This flag should not be set when calling C<aio_readdirx>. Instead, it
891is being set by C<aio_readdirx>, when any of the C<$type>'s found were 846is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
893C<$type>'s are known, which can be used to speed up some algorithms. 848C<$type>'s are known, which can be used to speed up some algorithms.
894 849
895=back 850=back
896 851
897 852
853=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
854
855Opens, reads and closes the given file. The data is put into C<$data>,
856which is resized as required.
857
858If C<$offset> is negative, then it is counted from the end of the file.
859
860If C<$length> is zero, then the remaining length of the file is
861used. Also, in this case, the same limitations to modifying C<$data> apply
862as when IO::AIO::mmap is used, i.e. it must only be modified in-place
863with C<substr>. If the size of the file is known, specifying a non-zero
864C<$length> results in a performance advantage.
865
866This request is similar to the older C<aio_load> request, but since it is
867a single request, it might be more efficient to use.
868
869Example: load F</etc/passwd> into C<$passwd>.
870
871 my $passwd;
872 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
873 $_[0] >= 0
874 or die "/etc/passwd: $!\n";
875
876 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
877 print $passwd;
878 };
879 IO::AIO::flush;
880
881
898=item aio_load $pathname, $data, $callback->($status) 882=item aio_load $pathname, $data, $callback->($status)
899 883
900This is a composite request that tries to fully load the given file into 884This is a composite request that tries to fully load the given file into
901memory. Status is the same as with aio_read. 885memory. Status is the same as with aio_read.
886
887Using C<aio_slurp> might be more efficient, as it is a single request.
902 888
903=cut 889=cut
904 890
905sub aio_load($$;$) { 891sub aio_load($$;$) {
906 my ($path, undef, $cb) = @_; 892 my ($path, undef, $cb) = @_;
… …
926=item aio_copy $srcpath, $dstpath, $callback->($status) 912=item aio_copy $srcpath, $dstpath, $callback->($status)
927 913
928Try to copy the I<file> (directories not supported as either source or 914Try to copy the I<file> (directories not supported as either source or
929destination) from C<$srcpath> to C<$dstpath> and call the callback with 915destination) from C<$srcpath> to C<$dstpath> and call the callback with
930a status of C<0> (ok) or C<-1> (error, see C<$!>). 916a status of C<0> (ok) or C<-1> (error, see C<$!>).
917
918Existing destination files will be truncated.
931 919
932This is a composite request that creates the destination file with 920This is a composite request that creates the destination file with
933mode 0200 and copies the contents of the source file into it using 921mode 0200 and copies the contents of the source file into it using
934C<aio_sendfile>, followed by restoring atime, mtime, access mode and 922C<aio_sendfile>, followed by restoring atime, mtime, access mode and
935uid/gid, in that order. 923uid/gid, in that order.
… …
1045Scans a directory (similar to C<aio_readdir>) but additionally tries to 1033Scans a directory (similar to C<aio_readdir>) but additionally tries to
1046efficiently separate the entries of directory C<$path> into two sets of 1034efficiently separate the entries of directory C<$path> into two sets of
1047names, directories you can recurse into (directories), and ones you cannot 1035names, directories you can recurse into (directories), and ones you cannot
1048recurse into (everything else, including symlinks to directories). 1036recurse into (everything else, including symlinks to directories).
1049 1037
1050C<aio_scandir> is a composite request that creates of many sub requests_ 1038C<aio_scandir> is a composite request that generates many sub requests.
1051C<$maxreq> specifies the maximum number of outstanding aio requests that 1039C<$maxreq> specifies the maximum number of outstanding aio requests that
1052this function generates. If it is C<< <= 0 >>, then a suitable default 1040this function generates. If it is C<< <= 0 >>, then a suitable default
1053will be chosen (currently 4). 1041will be chosen (currently 4).
1054 1042
1055On error, the callback is called without arguments, otherwise it receives 1043On error, the callback is called without arguments, otherwise it receives
… …
1221 }; 1209 };
1222 1210
1223 $grp 1211 $grp
1224} 1212}
1225 1213
1214=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1215
1216=item aio_ioctl $fh, $request, $buf, $callback->($status)
1217
1218These work just like the C<fcntl> and C<ioctl> built-in functions, except
1219they execute asynchronously and pass the return value to the callback.
1220
1221Both calls can be used for a lot of things, some of which make more sense
1222to run asynchronously in their own thread, while some others make less
1223sense. For example, calls that block waiting for external events, such
1224as locking, will also lock down an I/O thread while it is waiting, which
1225can deadlock the whole I/O system. At the same time, there might be no
1226alternative to using a thread to wait.
1227
1228So in general, you should only use these calls for things that do
1229(filesystem) I/O, not for things that wait for other events (network,
1230other processes), although if you are careful and know what you are doing,
1231you still can.
1232
1233The following constants are available (missing ones are, as usual C<0>):
1234
1235C<F_DUPFD_CLOEXEC>,
1236
1237C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1238
1239C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1240
1241C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1242C<FS_IOC_FIEMAP>.
1243
1244C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1245C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1246
1247C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1248C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1249C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1250C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1251C<FS_FL_USER_MODIFIABLE>.
1252
1253C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1254C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1255C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1256C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1257
1226=item aio_sync $callback->($status) 1258=item aio_sync $callback->($status)
1227 1259
1228Asynchronously call sync and call the callback when finished. 1260Asynchronously call sync and call the callback when finished.
1229 1261
1230=item aio_fsync $fh, $callback->($status) 1262=item aio_fsync $fh, $callback->($status)
… …
1298 }; 1330 };
1299 1331
1300 $grp 1332 $grp
1301} 1333}
1302 1334
1303=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1335=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1304 1336
1305This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1337This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1306scalars (see the C<IO::AIO::mmap> function, although it also works on data 1338scalars (see the C<IO::AIO::mmap> function, although it also works on data
1307scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1339scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1308scalar must only be modified in-place while an aio operation is pending on 1340scalar must only be modified in-place while an aio operation is pending on
… …
1310 1342
1311It calls the C<msync> function of your OS, if available, with the memory 1343It calls the C<msync> function of your OS, if available, with the memory
1312area starting at C<$offset> in the string and ending C<$length> bytes 1344area starting at C<$offset> in the string and ending C<$length> bytes
1313later. If C<$length> is negative, counts from the end, and if C<$length> 1345later. If C<$length> is negative, counts from the end, and if C<$length>
1314is C<undef>, then it goes till the end of the string. The flags can be 1346is C<undef>, then it goes till the end of the string. The flags can be
1315a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1347either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1316C<IO::AIO::MS_SYNC>. 1348C<IO::AIO::MS_INVALIDATE>.
1317 1349
1318=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1350=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1319 1351
1320This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1352This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1321scalars. 1353scalars.
… …
1404C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1436C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1405C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1437C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1406C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1438C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1407C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1439C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1408 1440
1409At the time of this writing (Linux 3.2), this requets is unreliable unless 1441At the time of this writing (Linux 3.2), this request is unreliable unless
1410C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1442C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1411it to return all extents of a range for files with large number of 1443it to return all extents of a range for files with a large number of
1412extents. The code works around all these issues if C<$count> is undef. 1444extents. The code (only) works around all these issues if C<$count> is
1445C<undef>.
1413 1446
1414=item aio_group $callback->(...) 1447=item aio_group $callback->(...)
1415 1448
1416This is a very special aio request: Instead of doing something, it is a 1449This is a very special aio request: Instead of doing something, it is a
1417container for other aio requests, which is useful if you want to bundle 1450container for other aio requests, which is useful if you want to bundle
… …
1501 aio_stat [$etcdir, "passwd"], sub { 1534 aio_stat [$etcdir, "passwd"], sub {
1502 # yay 1535 # yay
1503 }; 1536 };
1504 }; 1537 };
1505 1538
1506That C<aio_wd> is a request and not a normal function shows that creating 1539The fact that C<aio_wd> is a request and not a normal function shows that
1507an IO::AIO::WD object is itself a potentially blocking operation, which is 1540creating an IO::AIO::WD object is itself a potentially blocking operation,
1508why it is done asynchronously. 1541which is why it is done asynchronously.
1509 1542
1510To stat the directory obtained with C<aio_wd> above, one could write 1543To stat the directory obtained with C<aio_wd> above, one could write
1511either of the following three request calls: 1544either of the following three request calls:
1512 1545
1513 aio_lstat "/etc" , sub { ... # pathname as normal string 1546 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1530There are some caveats: when directories get renamed (or deleted), the 1563There are some caveats: when directories get renamed (or deleted), the
1531pathname string doesn't change, so will point to the new directory (or 1564pathname string doesn't change, so will point to the new directory (or
1532nowhere at all), while the directory fd, if available on the system, 1565nowhere at all), while the directory fd, if available on the system,
1533will still point to the original directory. Most functions accepting a 1566will still point to the original directory. Most functions accepting a
1534pathname will use the directory fd on newer systems, and the string on 1567pathname will use the directory fd on newer systems, and the string on
1535older systems. Some functions (such as realpath) will always rely on the 1568older systems. Some functions (such as C<aio_realpath>) will always rely on
1536string form of the pathname. 1569the string form of the pathname.
1537 1570
1538So this functionality is mainly useful to get some protection against 1571So this functionality is mainly useful to get some protection against
1539C<chdir>, to easily get an absolute path out of a relative path for future 1572C<chdir>, to easily get an absolute path out of a relative path for future
1540reference, and to speed up doing many operations in the same directory 1573reference, and to speed up doing many operations in the same directory
1541(e.g. when stat'ing all files in a directory). 1574(e.g. when stat'ing all files in a directory).
… …
1556passing C<undef> as working directory component of a pathname fails the 1589passing C<undef> as working directory component of a pathname fails the
1557request with C<ENOENT>, there is often no need for error checking in the 1590request with C<ENOENT>, there is often no need for error checking in the
1558C<aio_wd> callback, as future requests using the value will fail in the 1591C<aio_wd> callback, as future requests using the value will fail in the
1559expected way. 1592expected way.
1560 1593
1561If this call isn't available because your OS lacks it or it couldn't be
1562detected, it will be emulated by calling C<fsync> instead.
1563
1564=item IO::AIO::CWD 1594=item IO::AIO::CWD
1565 1595
1566This is a compiletime constant (object) that represents the process 1596This is a compiletime constant (object) that represents the process
1567current working directory. 1597current working directory.
1568 1598
… …
1935 1965
1936This is a very bad function to use in interactive programs because it 1966This is a very bad function to use in interactive programs because it
1937blocks, and a bad way to reduce concurrency because it is inexact: Better 1967blocks, and a bad way to reduce concurrency because it is inexact: Better
1938use an C<aio_group> together with a feed callback. 1968use an C<aio_group> together with a feed callback.
1939 1969
1940It's main use is in scripts without an event loop - when you want to stat 1970Its main use is in scripts without an event loop - when you want to stat
1941a lot of files, you can write somehting like this: 1971a lot of files, you can write something like this:
1942 1972
1943 IO::AIO::max_outstanding 32; 1973 IO::AIO::max_outstanding 32;
1944 1974
1945 for my $path (...) { 1975 for my $path (...) {
1946 aio_stat $path , ...; 1976 aio_stat $path , ...;
… …
1983Returns the number of requests currently in the pending state (executed, 2013Returns the number of requests currently in the pending state (executed,
1984but not yet processed by poll_cb). 2014but not yet processed by poll_cb).
1985 2015
1986=back 2016=back
1987 2017
2018=head3 SUBSECOND STAT TIME ACCESS
2019
2020Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2021generally find access/modification and change times with subsecond time
2022accuracy of the system supports it, but perl's built-in functions only
2023return the integer part.
2024
2025The following functions return the timestamps of the most recent
2026stat with subsecond precision on most systems and work both after
2027C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2028value is only meaningful after a successful C<stat>/C<lstat> call, or
2029during/after a successful C<aio_stat>/C<aio_lstat> callback.
2030
2031This is similar to the L<Time::HiRes> C<stat> functions, but can return
2032full resolution without rounding and work with standard perl C<stat>,
2033alleviating the need to call the special C<Time::HiRes> functions, which
2034do not act like their perl counterparts.
2035
2036On operating systems or file systems where subsecond time resolution is
2037not supported or could not be detected, a fractional part of C<0> is
2038returned, so it is always safe to call these functions.
2039
2040=over 4
2041
2042=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime
2043
2044Return the access, modication or change time, respectively, including
2045fractional part. Due to the limited precision of floating point, the
2046accuracy on most platforms is only a bit better than milliseconds for
2047times around now - see the I<nsec> function family, below, for full
2048accuracy.
2049
2050=item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtime
2051
2052Returns access, modification and change time all in one go, and maybe more
2053times in the future version.
2054
2055=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec
2056
2057Return the fractional access, modifcation or change time, in nanoseconds,
2058as an integer in the range C<0> to C<999999999>.
2059
2060=item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtimensec
2061
2062Like the functions above, but returns all three times in one go (and maybe
2063more in future versions).
2064
2065=back
2066
2067Example: print the high resolution modification time of F</etc>, using
2068C<stat>, and C<IO::AIO::aio_stat>.
2069
2070 if (stat "/etc") {
2071 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2072 }
2073
2074 IO::AIO::aio_stat "/etc", sub {
2075 $_[0]
2076 and return;
2077
2078 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2079 };
2080
2081 IO::AIO::flush;
2082
2083Output of the awbove on my system, showing reduced and full accuracy:
2084
2085 stat(/etc) mtime: 1534043702.020808
2086 aio_stat(/etc) mtime: 1534043702.020807792
2087
1988=head3 MISCELLANEOUS FUNCTIONS 2088=head3 MISCELLANEOUS FUNCTIONS
1989 2089
1990IO::AIO implements some functions that might be useful, but are not 2090IO::AIO implements some functions that are useful when you want to use
1991asynchronous. 2091some "Advanced I/O" function not available to in Perl, without going the
2092"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2093counterpart.
1992 2094
1993=over 4 2095=over 4
2096
2097=item $numfd = IO::AIO::get_fdlimit
2098
2099This function is I<EXPERIMENTAL> and subject to change.
2100
2101Tries to find the current file descriptor limit and returns it, or
2102C<undef> and sets C<$!> in case of an error. The limit is one larger than
2103the highest valid file descriptor number.
2104
2105=item IO::AIO::min_fdlimit [$numfd]
2106
2107This function is I<EXPERIMENTAL> and subject to change.
2108
2109Try to increase the current file descriptor limit(s) to at least C<$numfd>
2110by changing the soft or hard file descriptor resource limit. If C<$numfd>
2111is missing, it will try to set a very high limit, although this is not
2112recommended when you know the actual minimum that you require.
2113
2114If the limit cannot be raised enough, the function makes a best-effort
2115attempt to increase the limit as much as possible, using various
2116tricks, while still failing. You can query the resulting limit using
2117C<IO::AIO::get_fdlimit>.
2118
2119If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2120true.
1994 2121
1995=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2122=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1996 2123
1997Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2124Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1998but is blocking (this makes most sense if you know the input data is 2125but is blocking (this makes most sense if you know the input data is
… …
2015=item IO::AIO::madvise $scalar, $offset, $len, $advice 2142=item IO::AIO::madvise $scalar, $offset, $len, $advice
2016 2143
2017Simply calls the C<posix_madvise> function (see its 2144Simply calls the C<posix_madvise> function (see its
2018manpage for details). The following advice constants are 2145manpage for details). The following advice constants are
2019available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2146available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2020C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2147C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2148C<IO::AIO::MADV_DONTNEED>.
2149
2150If C<$offset> is negative, counts from the end. If C<$length> is negative,
2151the remaining length of the C<$scalar> is used. If possible, C<$length>
2152will be reduced to fit into the C<$scalar>.
2021 2153
2022On systems that do not implement C<posix_madvise>, this function returns 2154On systems that do not implement C<posix_madvise>, this function returns
2023ENOSYS, otherwise the return value of C<posix_madvise>. 2155ENOSYS, otherwise the return value of C<posix_madvise>.
2024 2156
2025=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2157=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2027Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2159Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2028$scalar (see its manpage for details). The following protect 2160$scalar (see its manpage for details). The following protect
2029constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2161constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2030C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2162C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2031 2163
2164If C<$offset> is negative, counts from the end. If C<$length> is negative,
2165the remaining length of the C<$scalar> is used. If possible, C<$length>
2166will be reduced to fit into the C<$scalar>.
2167
2032On systems that do not implement C<mprotect>, this function returns 2168On systems that do not implement C<mprotect>, this function returns
2033ENOSYS, otherwise the return value of C<mprotect>. 2169ENOSYS, otherwise the return value of C<mprotect>.
2034 2170
2035=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2171=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2036 2172
2037Memory-maps a file (or anonymous memory range) and attaches it to the 2173Memory-maps a file (or anonymous memory range) and attaches it to the
2038given C<$scalar>, which will act like a string scalar. Returns true on 2174given C<$scalar>, which will act like a string scalar. Returns true on
2039success, and false otherwise. 2175success, and false otherwise.
2040 2176
2177The scalar must exist, but its contents do not matter - this means you
2178cannot use a nonexistant array or hash element. When in doubt, C<undef>
2179the scalar first.
2180
2041The only operations allowed on the scalar are C<substr>/C<vec> that don't 2181The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2042change the string length, and most read-only operations such as copying it 2182which don't change the string length, and most read-only operations such
2043or searching it with regexes and so on. 2183as copying it or searching it with regexes and so on.
2044 2184
2045Anything else is unsafe and will, at best, result in memory leaks. 2185Anything else is unsafe and will, at best, result in memory leaks.
2046 2186
2047The memory map associated with the C<$scalar> is automatically removed 2187The memory map associated with the C<$scalar> is automatically removed
2048when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2188when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2049C<IO::AIO::munmap> functions are called. 2189or C<IO::AIO::munmap> functions are called on it.
2050 2190
2051This calls the C<mmap>(2) function internally. See your system's manual 2191This calls the C<mmap>(2) function internally. See your system's manual
2052page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2192page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2053 2193
2054The C<$length> must be larger than zero and smaller than the actual 2194The C<$length> must be larger than zero and smaller than the actual
2055filesize. 2195filesize.
2056 2196
2057C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2197C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2058C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2198C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2059 2199
2060C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2200C<$flags> can be a combination of
2061C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2201C<IO::AIO::MAP_SHARED> or
2062not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2202C<IO::AIO::MAP_PRIVATE>,
2203or a number of system-specific flags (when not available, the are C<0>):
2063(which is set to C<MAP_ANON> if your system only provides this 2204C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2064constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2205C<IO::AIO::MAP_LOCKED>,
2065C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2206C<IO::AIO::MAP_NORESERVE>,
2207C<IO::AIO::MAP_POPULATE>,
2066C<IO::AIO::MAP_NONBLOCK> 2208C<IO::AIO::MAP_NONBLOCK>,
2209C<IO::AIO::MAP_FIXED>,
2210C<IO::AIO::MAP_GROWSDOWN>,
2211C<IO::AIO::MAP_32BIT>,
2212C<IO::AIO::MAP_HUGETLB> or
2213C<IO::AIO::MAP_STACK>.
2067 2214
2068If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2215If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2069 2216
2070C<$offset> is the offset from the start of the file - it generally must be 2217C<$offset> is the offset from the start of the file - it generally must be
2071a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2218a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2084 my $fast_md5 = md5 $data; 2231 my $fast_md5 = md5 $data;
2085 2232
2086=item IO::AIO::munmap $scalar 2233=item IO::AIO::munmap $scalar
2087 2234
2088Removes a previous mmap and undefines the C<$scalar>. 2235Removes a previous mmap and undefines the C<$scalar>.
2236
2237=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2238
2239Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2240been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2241C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2242
2243Returns true if successful, and false otherwise. If the underlying mmapped
2244region has changed address, then the true value has the numerical value
2245C<1>, otherwise it has the numerical value C<0>:
2246
2247 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2248 or die "mremap: $!";
2249
2250 if ($success*1) {
2251 warn "scalar has chanegd address in memory\n";
2252 }
2253
2254C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2255implemented, but not supported and might go away in a future version.
2256
2257On systems where this call is not supported or is not emulated, this call
2258returns falls and sets C<$!> to C<ENOSYS>.
2089 2259
2090=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2260=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2091 2261
2092Calls the C<munlock> function, undoing the effects of a previous 2262Calls the C<munlock> function, undoing the effects of a previous
2093C<aio_mlock> call (see its description for details). 2263C<aio_mlock> call (see its description for details).
… …
2114 2284
2115See the C<splice(2)> manpage for details. 2285See the C<splice(2)> manpage for details.
2116 2286
2117=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2287=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2118 2288
2119Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2289Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2120description for C<IO::AIO::splice> above for details. 2290description for C<IO::AIO::splice> above for details.
2291
2292=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2293
2294Attempts to query or change the pipe buffer size. Obviously works only
2295on pipes, and currently works only on GNU/Linux systems, and fails with
2296C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2297size on other systems, drop me a note.
2298
2299=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2300
2301This is a direct interface to the Linux L<pipe2(2)> system call. If
2302C<$flags> is missing or C<0>, then this should be the same as a call to
2303perl's built-in C<pipe> function and create a new pipe, and works on
2304systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2305(..., 4096, O_BINARY)>.
2306
2307If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2308the given flags (Linux 2.6.27, glibc 2.9).
2309
2310On success, the read and write file handles are returned.
2311
2312On error, nothing will be returned. If the pipe2 syscall is missing and
2313C<$flags> is non-zero, fails with C<ENOSYS>.
2314
2315Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2316time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2317C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2318
2319Example: create a pipe race-free w.r.t. threads and fork:
2320
2321 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2322 or die "pipe2: $!\n";
2323
2324=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2325
2326This is a direct interface to the Linux L<eventfd(2)> system call. The
2327(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2328
2329On success, the new eventfd filehandle is returned, otherwise returns
2330C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2331
2332Please refer to L<eventfd(2)> for more info on this call.
2333
2334The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2335C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2336
2337Example: create a new eventfd filehandle:
2338
2339 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2340 or die "eventfd: $!\n";
2341
2342=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2343
2344This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2345(unhelpful) default for C<$flags> is C<0>.
2346
2347On success, the new timerfd filehandle is returned, otherwise returns
2348C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2349
2350Please refer to L<timerfd_create(2)> for more info on this call.
2351
2352The following C<$clockid> values are
2353available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2354C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2355C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2356C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2357
2358The following C<$flags> values are available (Linux
23592.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2360
2361Example: create a new timerfd and set it to one-second repeated alarms,
2362then wait for two alarms:
2363
2364 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2365 or die "timerfd_create: $!\n";
2366
2367 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2368 or die "timerfd_settime: $!\n";
2369
2370 for (1..2) {
2371 8 == sysread $fh, my $buf, 8
2372 or die "timerfd read failure\n";
2373
2374 printf "number of expirations (likely 1): %d\n",
2375 unpack "Q", $buf;
2376 }
2377
2378=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2379
2380This is a direct interface to the Linux L<timerfd_settime(2)> system
2381call. Please refer to its manpage for more info on this call.
2382
2383The new itimerspec is specified using two (possibly fractional) second
2384values, C<$new_interval> and C<$new_value>).
2385
2386On success, the current interval and value are returned (as per
2387C<timerfd_gettime>). On failure, the empty list is returned.
2388
2389The following C<$flags> values are
2390available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2391C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2392
2393See C<IO::AIO::timerfd_create> for a full example.
2394
2395=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2396
2397This is a direct interface to the Linux L<timerfd_gettime(2)> system
2398call. Please refer to its manpage for more info on this call.
2399
2400On success, returns the current values of interval and value for the given
2401timerfd (as potentially fractional second values). On failure, the empty
2402list is returned.
2121 2403
2122=back 2404=back
2123 2405
2124=cut 2406=cut
2125 2407
… …
2191the process will result in undefined behaviour. Calling it at any time 2473the process will result in undefined behaviour. Calling it at any time
2192will also result in any undefined (by POSIX) behaviour. 2474will also result in any undefined (by POSIX) behaviour.
2193 2475
2194=back 2476=back
2195 2477
2478=head2 LINUX-SPECIFIC CALLS
2479
2480When a call is documented as "linux-specific" then this means it
2481originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2482availability and compatibility of such calls regardless of the platform
2483it is compiled on, so platforms such as FreeBSD which often implement
2484these calls will work. When in doubt, call them and see if they fail wth
2485C<ENOSYS>.
2486
2196=head2 MEMORY USAGE 2487=head2 MEMORY USAGE
2197 2488
2198Per-request usage: 2489Per-request usage:
2199 2490
2200Each aio request uses - depending on your architecture - around 100-200 2491Each aio request uses - depending on your architecture - around 100-200
… …
2212temporary buffers, and each thread requires a stack and other data 2503temporary buffers, and each thread requires a stack and other data
2213structures (usually around 16k-128k, depending on the OS). 2504structures (usually around 16k-128k, depending on the OS).
2214 2505
2215=head1 KNOWN BUGS 2506=head1 KNOWN BUGS
2216 2507
2217Known bugs will be fixed in the next release. 2508Known bugs will be fixed in the next release :)
2509
2510=head1 KNOWN ISSUES
2511
2512Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2513or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2514non-created hash slots or other scalars I didn't think of. It's best to
2515avoid such and either use scalar variables or making sure that the scalar
2516exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2517
2518I am not sure anything can be done about this, so this is considered a
2519known issue, rather than a bug.
2218 2520
2219=head1 SEE ALSO 2521=head1 SEE ALSO
2220 2522
2221L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2523L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2222more natural syntax. 2524more natural syntax.

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