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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.257 by root, Mon Jan 18 11:53:09 2016 UTC vs.
Revision 1.289 by root, Sun Aug 12 05:21:35 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
… …
167use common::sense; 171use common::sense;
168 172
169use base 'Exporter'; 173use base 'Exporter';
170 174
171BEGIN { 175BEGIN {
172 our $VERSION = 4.33; 176 our $VERSION = 4.5;
173 177
174 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
175 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
176 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
177 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
178 aio_pathsync aio_readahead aio_fiemap 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
179 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
180 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
181 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
182 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
183 aio_statvfs 187 aio_statvfs
188 aio_slurp
184 aio_wd); 189 aio_wd);
185 190
186 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
187 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
188 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
189 nreqs nready npending nthreads 194 nreqs nready npending nthreads
190 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
191 sendfile fadvise madvise 196 sendfile fadvise madvise
192 mmap munmap munlock munlockall); 197 mmap munmap mremap munlock munlockall);
193 198
194 push @AIO_REQ, qw(aio_busy); # not exported 199 push @AIO_REQ, qw(aio_busy); # not exported
195 200
196 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
197 202
… …
229 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
230 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
231 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
232 aio_realpath $pathname, $callback->($path) 237 aio_realpath $pathname, $callback->($path)
233 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
234 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
235 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
236 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
237 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
238 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
240 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
241 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
242 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
243 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
244 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)
245 aio_sync $callback->($status) 253 aio_sync $callback->($status)
246 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
247 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
248 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
249 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
250 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
251 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
252 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
253 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
254 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
255 aio_group $callback->(...) 263 aio_group $callback->(...)
256 aio_nop $callback->() 264 aio_nop $callback->()
… …
270 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
271 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
272 IO::AIO::nreqs 280 IO::AIO::nreqs
273 IO::AIO::nready 281 IO::AIO::nready
274 IO::AIO::npending 282 IO::AIO::npending
283 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
284 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
275 285
276 IO::AIO::sendfile $ofh, $ifh, $offset, $count 286 IO::AIO::sendfile $ofh, $ifh, $offset, $count
277 IO::AIO::fadvise $fh, $offset, $len, $advice 287 IO::AIO::fadvise $fh, $offset, $len, $advice
278 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 288 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
279 IO::AIO::munmap $scalar 289 IO::AIO::munmap $scalar
290 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
280 IO::AIO::madvise $scalar, $offset, $length, $advice 291 IO::AIO::madvise $scalar, $offset, $length, $advice
281 IO::AIO::mprotect $scalar, $offset, $length, $protect 292 IO::AIO::mprotect $scalar, $offset, $length, $protect
282 IO::AIO::munlock $scalar, $offset = 0, $length = undef 293 IO::AIO::munlock $scalar, $offset = 0, $length = undef
283 IO::AIO::munlockall 294 IO::AIO::munlockall
284 295
… …
394following POSIX and non-POSIX constants are available (missing ones on 405following POSIX and non-POSIX constants are available (missing ones on
395your system are, as usual, C<0>): 406your system are, as usual, C<0>):
396 407
397C<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>,
398C<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>,
399C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, 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>.
400 411
401 412
402=item aio_close $fh, $callback->($status) 413=item aio_close $fh, $callback->($status)
403 414
404Asynchronously close a file and call the callback with the result 415Asynchronously close a file and call the callback with the result
… …
439=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 450=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
440 451
441=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 452=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
442 453
443Reads 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
444C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 455C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
445and 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
446error, just like the syscall). 457error, just like the syscall).
447 458
448C<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
449offset plus the actual number of bytes read. 460offset plus the actual number of bytes read.
450 461
… …
508As native sendfile syscalls (as practically any non-POSIX interface hacked 519As native sendfile syscalls (as practically any non-POSIX interface hacked
509together 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
510on many systems, this implementation tries to work around some known bugs 521on many systems, this implementation tries to work around some known bugs
511in Linux and FreeBSD kernels (probably others, too), but that might fail, 522in Linux and FreeBSD kernels (probably others, too), but that might fail,
512so 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> -
513fewre bytes than expected might have been transferred. 524fewer bytes than expected might have been transferred.
514 525
515 526
516=item aio_readahead $fh,$offset,$length, $callback->($retval) 527=item aio_readahead $fh,$offset,$length, $callback->($retval)
517 528
518C<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
… …
522whole 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
523and 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
524(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
525file. The current file offset of the file is left unchanged. 536file. The current file offset of the file is left unchanged.
526 537
527If 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
528emulated by simply reading the data, which would have a similar effect. 539be emulated by simply reading the data, which would have a similar effect.
529 540
530 541
531=item aio_stat $fh_or_path, $callback->($status) 542=item aio_stat $fh_or_path, $callback->($status)
532 543
533=item aio_lstat $fh, $callback->($status) 544=item aio_lstat $fh, $callback->($status)
… …
549behaviour). 560behaviour).
550 561
551C<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>,
552C<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>,
553C<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>.
554 568
555Example: Print the length of F</etc/passwd>: 569Example: Print the length of F</etc/passwd>:
556 570
557 aio_stat "/etc/passwd", sub { 571 aio_stat "/etc/passwd", sub {
558 $_[0] and die "stat failed: $!"; 572 $_[0] and die "stat failed: $!";
… …
602 namemax => 255, 616 namemax => 255,
603 frsize => 1024, 617 frsize => 1024,
604 fsid => 1810 618 fsid => 1810
605 } 619 }
606 620
607Here is a (likely partial - send me updates!) list of fsid values used by
608Linux - it is safe to hardcode these when C<$^O> is C<linux>:
609
610 0x0000adf5 adfs
611 0x0000adff affs
612 0x5346414f afs
613 0x09041934 anon-inode filesystem
614 0x00000187 autofs
615 0x42465331 befs
616 0x1badface bfs
617 0x42494e4d binfmt_misc
618 0x9123683e btrfs
619 0x0027e0eb cgroupfs
620 0xff534d42 cifs
621 0x73757245 coda
622 0x012ff7b7 coh
623 0x28cd3d45 cramfs
624 0x453dcd28 cramfs-wend (wrong endianness)
625 0x64626720 debugfs
626 0x00001373 devfs
627 0x00001cd1 devpts
628 0x0000f15f ecryptfs
629 0x00414a53 efs
630 0x0000137d ext
631 0x0000ef53 ext2/ext3/ext4
632 0x0000ef51 ext2
633 0xf2f52010 f2fs
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 0x00c0ffee hostfs
643 0x958458f6 hugetlbfs
644 0x2bad1dea inotifyfs
645 0x00009660 isofs
646 0x000072b6 jffs2
647 0x3153464a jfs
648 0x6b414653 k-afs
649 0x0bd00bd0 lustre
650 0x0000137f minix
651 0x0000138f minix 30 char names
652 0x00002468 minix v2
653 0x00002478 minix v2 30 char names
654 0x00004d5a minix v3
655 0x19800202 mqueue
656 0x00004d44 msdos
657 0x0000564c novell
658 0x00006969 nfs
659 0x6e667364 nfsd
660 0x00003434 nilfs
661 0x5346544e ntfs
662 0x00009fa1 openprom
663 0x7461636F ocfs2
664 0x00009fa0 proc
665 0x6165676c pstorefs
666 0x0000002f qnx4
667 0x68191122 qnx6
668 0x858458f6 ramfs
669 0x52654973 reiserfs
670 0x00007275 romfs
671 0x67596969 rpc_pipefs
672 0x73636673 securityfs
673 0xf97cff8c selinux
674 0x0000517b smb
675 0x534f434b sockfs
676 0x73717368 squashfs
677 0x62656572 sysfs
678 0x012ff7b6 sysv2
679 0x012ff7b5 sysv4
680 0x01021994 tmpfs
681 0x15013346 udf
682 0x00011954 ufs
683 0x54190100 ufs byteswapped
684 0x00009fa2 usbdevfs
685 0x01021997 v9fs
686 0xa501fcf5 vxfs
687 0xabba1974 xenfs
688 0x012ff7b4 xenix
689 0x58465342 xfs
690 0x012fd16d xia
691
692=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 621=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
693 622
694Works 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
695and $mtime being undef). Fractional times are supported if the underlying 624and $mtime being undef). Fractional times are supported if the underlying
696syscalls support them. 625syscalls support them.
… …
733C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate 662C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
734space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>, 663space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
735to deallocate a file range. 664to deallocate a file range.
736 665
737IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range 666IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
738(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see 667(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
739your L<fallocate(2)> manpage). 668C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
669to unshare shared blocks (see your L<fallocate(2)> manpage).
740 670
741The file system block size used by C<fallocate> is presumably the 671The file system block size used by C<fallocate> is presumably the
742C<f_bsize> returned by C<statvfs>. 672C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
673can dictate other limitations.
743 674
744If C<fallocate> isn't available or cannot be emulated (currently no 675If C<fallocate> isn't available or cannot be emulated (currently no
745emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 676emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
746 677
747 678
… …
806On systems that support the AIO::WD working directory abstraction 737On systems that support the AIO::WD working directory abstraction
807natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 738natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
808of failing, C<rename> is called on the absolute path of C<$wd>. 739of failing, C<rename> is called on the absolute path of C<$wd>.
809 740
810 741
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
811=item aio_mkdir $pathname, $mode, $callback->($status) 758=item aio_mkdir $pathname, $mode, $callback->($status)
812 759
813Asynchronously mkdir (create) a directory and call the callback with 760Asynchronously mkdir (create) a directory and call the callback with
814the 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
815request is executed, so do not change your umask. 762request is executed, so do not change your umask.
… …
846 793
847=over 4 794=over 4
848 795
849=item IO::AIO::READDIR_DENTS 796=item IO::AIO::READDIR_DENTS
850 797
851When this flag is off, then the callback gets an arrayref consisting of 798Normally the callback gets an arrayref consisting of names only (as
852names 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
853C<[$name, $type, $inode]> arrayrefs, each describing a single directory 800arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
854entry in more detail. 801single directory entry in more detail:
855 802
856C<$name> is the name of the entry. 803C<$name> is the name of the entry.
857 804
858C<$type> is one of the C<IO::AIO::DT_xxx> constants: 805C<$type> is one of the C<IO::AIO::DT_xxx> constants:
859 806
860C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 807C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
861C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 808C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
862C<IO::AIO::DT_WHT>. 809C<IO::AIO::DT_WHT>.
863 810
864C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 811C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
865know, you have to run stat yourself. Also, for speed reasons, the C<$type> 812to know, you have to run stat yourself. Also, for speed/memory reasons,
866scalars are read-only: you can not modify them. 813the C<$type> scalars are read-only: you must not modify them.
867 814
868C<$inode> is the inode number (which might not be exact on systems with 64 815C<$inode> is the inode number (which might not be exact on systems with 64
869bit inode numbers and 32 bit perls). This field has unspecified content on 816bit inode numbers and 32 bit perls). This field has unspecified content on
870systems that do not deliver the inode information. 817systems that do not deliver the inode information.
871 818
… …
882short names are tried first. 829short names are tried first.
883 830
884=item IO::AIO::READDIR_STAT_ORDER 831=item IO::AIO::READDIR_STAT_ORDER
885 832
886When this flag is set, then the names will be returned in an order 833When this flag is set, then the names will be returned in an order
887suitable for stat()'ing each one. That is, when you plan to stat() 834suitable for stat()'ing each one. That is, when you plan to stat() most or
888all files in the given directory, then the returned order will likely 835all files in the given directory, then the returned order will likely be
889be fastest. 836faster.
890 837
891If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 838If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
892the likely dirs come first, resulting in a less optimal stat order. 839then the likely dirs come first, resulting in a less optimal stat order
840for stat'ing all entries, but likely a more optimal order for finding
841subdirectories.
893 842
894=item IO::AIO::READDIR_FOUND_UNKNOWN 843=item IO::AIO::READDIR_FOUND_UNKNOWN
895 844
896This flag should not be set when calling C<aio_readdirx>. Instead, it 845This flag should not be set when calling C<aio_readdirx>. Instead, it
897is being set by C<aio_readdirx>, when any of the C<$type>'s found were 846is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
899C<$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.
900 849
901=back 850=back
902 851
903 852
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
904=item aio_load $pathname, $data, $callback->($status) 882=item aio_load $pathname, $data, $callback->($status)
905 883
906This 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
907memory. 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.
908 888
909=cut 889=cut
910 890
911sub aio_load($$;$) { 891sub aio_load($$;$) {
912 my ($path, undef, $cb) = @_; 892 my ($path, undef, $cb) = @_;
… …
932=item aio_copy $srcpath, $dstpath, $callback->($status) 912=item aio_copy $srcpath, $dstpath, $callback->($status)
933 913
934Try 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
935destination) from C<$srcpath> to C<$dstpath> and call the callback with 915destination) from C<$srcpath> to C<$dstpath> and call the callback with
936a 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.
937 919
938This is a composite request that creates the destination file with 920This is a composite request that creates the destination file with
939mode 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
940C<aio_sendfile>, followed by restoring atime, mtime, access mode and 922C<aio_sendfile>, followed by restoring atime, mtime, access mode and
941uid/gid, in that order. 923uid/gid, in that order.
… …
1051Scans a directory (similar to C<aio_readdir>) but additionally tries to 1033Scans a directory (similar to C<aio_readdir>) but additionally tries to
1052efficiently separate the entries of directory C<$path> into two sets of 1034efficiently separate the entries of directory C<$path> into two sets of
1053names, directories you can recurse into (directories), and ones you cannot 1035names, directories you can recurse into (directories), and ones you cannot
1054recurse into (everything else, including symlinks to directories). 1036recurse into (everything else, including symlinks to directories).
1055 1037
1056C<aio_scandir> is a composite request that creates of many sub requests_ 1038C<aio_scandir> is a composite request that generates many sub requests.
1057C<$maxreq> specifies the maximum number of outstanding aio requests that 1039C<$maxreq> specifies the maximum number of outstanding aio requests that
1058this function generates. If it is C<< <= 0 >>, then a suitable default 1040this function generates. If it is C<< <= 0 >>, then a suitable default
1059will be chosen (currently 4). 1041will be chosen (currently 4).
1060 1042
1061On error, the callback is called without arguments, otherwise it receives 1043On error, the callback is called without arguments, otherwise it receives
… …
1227 }; 1209 };
1228 1210
1229 $grp 1211 $grp
1230} 1212}
1231 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
1232=item aio_sync $callback->($status) 1258=item aio_sync $callback->($status)
1233 1259
1234Asynchronously call sync and call the callback when finished. 1260Asynchronously call sync and call the callback when finished.
1235 1261
1236=item aio_fsync $fh, $callback->($status) 1262=item aio_fsync $fh, $callback->($status)
… …
1304 }; 1330 };
1305 1331
1306 $grp 1332 $grp
1307} 1333}
1308 1334
1309=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)
1310 1336
1311This 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
1312scalars (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
1313scalars 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
1314scalar 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
… …
1316 1342
1317It 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
1318area 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
1319later. 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>
1320is 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
1321a 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
1322C<IO::AIO::MS_SYNC>. 1348C<IO::AIO::MS_INVALIDATE>.
1323 1349
1324=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)
1325 1351
1326This 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
1327scalars. 1353scalars.
… …
1410C<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>,
1411C<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>,
1412C<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
1413C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1439C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1414 1440
1415At 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
1416C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1442C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1417it 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
1418extents. 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>.
1419 1446
1420=item aio_group $callback->(...) 1447=item aio_group $callback->(...)
1421 1448
1422This 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
1423container 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
… …
1536There are some caveats: when directories get renamed (or deleted), the 1563There are some caveats: when directories get renamed (or deleted), the
1537pathname 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
1538nowhere at all), while the directory fd, if available on the system, 1565nowhere at all), while the directory fd, if available on the system,
1539will still point to the original directory. Most functions accepting a 1566will still point to the original directory. Most functions accepting a
1540pathname 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
1541older systems. Some functions (such as realpath) will always rely on the 1568older systems. Some functions (such as C<aio_realpath>) will always rely on
1542string form of the pathname. 1569the string form of the pathname.
1543 1570
1544So this functionality is mainly useful to get some protection against 1571So this functionality is mainly useful to get some protection against
1545C<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
1546reference, and to speed up doing many operations in the same directory 1573reference, and to speed up doing many operations in the same directory
1547(e.g. when stat'ing all files in a directory). 1574(e.g. when stat'ing all files in a directory).
… …
1939This 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
1940blocks, 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
1941use an C<aio_group> together with a feed callback. 1968use an C<aio_group> together with a feed callback.
1942 1969
1943Its 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
1944a lot of files, you can write somehting like this: 1971a lot of files, you can write something like this:
1945 1972
1946 IO::AIO::max_outstanding 32; 1973 IO::AIO::max_outstanding 32;
1947 1974
1948 for my $path (...) { 1975 for my $path (...) {
1949 aio_stat $path , ...; 1976 aio_stat $path , ...;
… …
1986Returns the number of requests currently in the pending state (executed, 2013Returns the number of requests currently in the pending state (executed,
1987but not yet processed by poll_cb). 2014but not yet processed by poll_cb).
1988 2015
1989=back 2016=back
1990 2017
2018=head3 SUBSECOND STAT TIME ACCESS
2019
2020Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2021generally find access/modification and change times with subsecond time
2022accuracy of the system supports it, but perl's built-in functions only
2023return the integer part.
2024
2025The following functions return the timestamps of the most recent
2026stat with subsecond precision on most systems and work both after
2027C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2028value is only meaningful after a successful C<stat>/C<lstat> call, or
2029during/after a successful C<aio_stat>/C<aio_lstat> callback.
2030
2031This is similar to the L<Time::HiRes> C<stat> functions, but can return
2032full resolution without rounding and work with standard perl C<stat>,
2033alleviating the need to call the special C<Time::HiRes> functions, which
2034do not act like their perl counterparts.
2035
2036On operating systems or file systems where subsecond time resolution is
2037not supported or could not be detected, a fractional part of C<0> is
2038returned, so it is always safe to call these functions.
2039
2040=over 4
2041
2042=item IO::AIO::stat_atime, IO::AIO::stat_mtime, IO::AIO::stat_ctime
2043
2044Return the access, modication or change time, respectively, including
2045fractional part. Due to the limited precision of floating point, the
2046accuracy on most platforms is only a bit better than milliseconds for
2047times around now - see the I<nsec> function family, below, for full
2048accuracy.
2049
2050=item ($atime, $mtime, $ctime, ...) = IO::AIO::stat_xtime
2051
2052Returns access, modification and change time all in one go, and maybe more
2053times in the future version.
2054
2055=item IO::AIO::stat_atimensec, IO::AIO::stat_mtimensec, IO::AIO::stat_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=back
2061
2062Example: print the high resolution modification time of F</etc>, using
2063C<stat>, and C<IO::AIO::aio_stat>.
2064
2065 if (stat "/etc") {
2066 printf "stat(/etc) mtime: %f\n", IO::AIO::stat_mtime;
2067 }
2068
2069 IO::AIO::aio_stat "/etc", sub {
2070 $_[0]
2071 and return;
2072
2073 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::stat_mtimensec;
2074 };
2075
2076 IO::AIO::flush;
2077
2078Output of the awbove on my system, showing reduced and full accuracy:
2079
2080 stat(/etc) mtime: 1534043702.020808
2081 aio_stat(/etc) mtime: 1534043702.020807792
2082
1991=head3 MISCELLANEOUS FUNCTIONS 2083=head3 MISCELLANEOUS FUNCTIONS
1992 2084
1993IO::AIO implements some functions that are useful when you want to use 2085IO::AIO implements some functions that are useful when you want to use
1994some "Advanced I/O" function not available to in Perl, without going the 2086some "Advanced I/O" function not available to in Perl, without going the
1995"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*> 2087"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
1996counterpart. 2088counterpart.
1997 2089
1998=over 4 2090=over 4
2091
2092=item $numfd = IO::AIO::get_fdlimit
2093
2094This function is I<EXPERIMENTAL> and subject to change.
2095
2096Tries to find the current file descriptor limit and returns it, or
2097C<undef> and sets C<$!> in case of an error. The limit is one larger than
2098the highest valid file descriptor number.
2099
2100=item IO::AIO::min_fdlimit [$numfd]
2101
2102This function is I<EXPERIMENTAL> and subject to change.
2103
2104Try to increase the current file descriptor limit(s) to at least C<$numfd>
2105by changing the soft or hard file descriptor resource limit. If C<$numfd>
2106is missing, it will try to set a very high limit, although this is not
2107recommended when you know the actual minimum that you require.
2108
2109If the limit cannot be raised enough, the function makes a best-effort
2110attempt to increase the limit as much as possible, using various
2111tricks, while still failing. You can query the resulting limit using
2112C<IO::AIO::get_fdlimit>.
2113
2114If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2115true.
1999 2116
2000=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2117=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
2001 2118
2002Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2119Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
2003but is blocking (this makes most sense if you know the input data is 2120but is blocking (this makes most sense if you know the input data is
… …
2020=item IO::AIO::madvise $scalar, $offset, $len, $advice 2137=item IO::AIO::madvise $scalar, $offset, $len, $advice
2021 2138
2022Simply calls the C<posix_madvise> function (see its 2139Simply calls the C<posix_madvise> function (see its
2023manpage for details). The following advice constants are 2140manpage for details). The following advice constants are
2024available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2141available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2025C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2142C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2143C<IO::AIO::MADV_DONTNEED>.
2144
2145If C<$offset> is negative, counts from the end. If C<$length> is negative,
2146the remaining length of the C<$scalar> is used. If possible, C<$length>
2147will be reduced to fit into the C<$scalar>.
2026 2148
2027On systems that do not implement C<posix_madvise>, this function returns 2149On systems that do not implement C<posix_madvise>, this function returns
2028ENOSYS, otherwise the return value of C<posix_madvise>. 2150ENOSYS, otherwise the return value of C<posix_madvise>.
2029 2151
2030=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2152=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2032Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2154Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2033$scalar (see its manpage for details). The following protect 2155$scalar (see its manpage for details). The following protect
2034constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2156constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2035C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2157C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2036 2158
2159If C<$offset> is negative, counts from the end. If C<$length> is negative,
2160the remaining length of the C<$scalar> is used. If possible, C<$length>
2161will be reduced to fit into the C<$scalar>.
2162
2037On systems that do not implement C<mprotect>, this function returns 2163On systems that do not implement C<mprotect>, this function returns
2038ENOSYS, otherwise the return value of C<mprotect>. 2164ENOSYS, otherwise the return value of C<mprotect>.
2039 2165
2040=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2166=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2041 2167
2042Memory-maps a file (or anonymous memory range) and attaches it to the 2168Memory-maps a file (or anonymous memory range) and attaches it to the
2043given C<$scalar>, which will act like a string scalar. Returns true on 2169given C<$scalar>, which will act like a string scalar. Returns true on
2044success, and false otherwise. 2170success, and false otherwise.
2045 2171
2172The scalar must exist, but its contents do not matter - this means you
2173cannot use a nonexistant array or hash element. When in doubt, C<undef>
2174the scalar first.
2175
2046The only operations allowed on the scalar are C<substr>/C<vec> that don't 2176The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2047change the string length, and most read-only operations such as copying it 2177which don't change the string length, and most read-only operations such
2048or searching it with regexes and so on. 2178as copying it or searching it with regexes and so on.
2049 2179
2050Anything else is unsafe and will, at best, result in memory leaks. 2180Anything else is unsafe and will, at best, result in memory leaks.
2051 2181
2052The memory map associated with the C<$scalar> is automatically removed 2182The memory map associated with the C<$scalar> is automatically removed
2053when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2183when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2054C<IO::AIO::munmap> functions are called. 2184or C<IO::AIO::munmap> functions are called on it.
2055 2185
2056This calls the C<mmap>(2) function internally. See your system's manual 2186This calls the C<mmap>(2) function internally. See your system's manual
2057page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2187page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2058 2188
2059The C<$length> must be larger than zero and smaller than the actual 2189The C<$length> must be larger than zero and smaller than the actual
… …
2065C<$flags> can be a combination of 2195C<$flags> can be a combination of
2066C<IO::AIO::MAP_SHARED> or 2196C<IO::AIO::MAP_SHARED> or
2067C<IO::AIO::MAP_PRIVATE>, 2197C<IO::AIO::MAP_PRIVATE>,
2068or a number of system-specific flags (when not available, the are C<0>): 2198or a number of system-specific flags (when not available, the are C<0>):
2069C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant), 2199C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2070C<IO::AIO::MAP_HUGETLB>,
2071C<IO::AIO::MAP_LOCKED>, 2200C<IO::AIO::MAP_LOCKED>,
2072C<IO::AIO::MAP_NORESERVE>, 2201C<IO::AIO::MAP_NORESERVE>,
2073C<IO::AIO::MAP_POPULATE>, 2202C<IO::AIO::MAP_POPULATE>,
2074C<IO::AIO::MAP_NONBLOCK>, 2203C<IO::AIO::MAP_NONBLOCK>,
2075C<IO::AIO::MAP_FIXED>, 2204C<IO::AIO::MAP_FIXED>,
… …
2098 2227
2099=item IO::AIO::munmap $scalar 2228=item IO::AIO::munmap $scalar
2100 2229
2101Removes a previous mmap and undefines the C<$scalar>. 2230Removes a previous mmap and undefines the C<$scalar>.
2102 2231
2232=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2233
2234Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2235been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2236C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2237
2238Returns true if successful, and false otherwise. If the underlying mmapped
2239region has changed address, then the true value has the numerical value
2240C<1>, otherwise it has the numerical value C<0>:
2241
2242 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2243 or die "mremap: $!";
2244
2245 if ($success*1) {
2246 warn "scalar has chanegd address in memory\n";
2247 }
2248
2249C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2250implemented, but not supported and might go away in a future version.
2251
2252On systems where this call is not supported or is not emulated, this call
2253returns falls and sets C<$!> to C<ENOSYS>.
2254
2103=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2255=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2104 2256
2105Calls the C<munlock> function, undoing the effects of a previous 2257Calls the C<munlock> function, undoing the effects of a previous
2106C<aio_mlock> call (see its description for details). 2258C<aio_mlock> call (see its description for details).
2107 2259
… …
2156C<$flags> is non-zero, fails with C<ENOSYS>. 2308C<$flags> is non-zero, fails with C<ENOSYS>.
2157 2309
2158Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the 2310Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2159time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and 2311time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2160C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported. 2312C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2313
2314Example: create a pipe race-free w.r.t. threads and fork:
2315
2316 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2317 or die "pipe2: $!\n";
2318
2319=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2320
2321This is a direct interface to the Linux L<eventfd(2)> system call. The
2322(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2323
2324On success, the new eventfd filehandle is returned, otherwise returns
2325C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2326
2327Please refer to L<eventfd(2)> for more info on this call.
2328
2329The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2330C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2331
2332Example: create a new eventfd filehandle:
2333
2334 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2335 or die "eventfd: $!\n";
2336
2337=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2338
2339This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2340(unhelpful) default for C<$flags> is C<0>.
2341
2342On success, the new timerfd filehandle is returned, otherwise returns
2343C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2344
2345Please refer to L<timerfd_create(2)> for more info on this call.
2346
2347The following C<$clockid> values are
2348available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2349C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2350C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2351C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2352
2353The following C<$flags> values are available (Linux
23542.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2355
2356Example: create a new timerfd and set it to one-second repeated alarms,
2357then wait for two alarms:
2358
2359 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2360 or die "timerfd_create: $!\n";
2361
2362 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2363 or die "timerfd_settime: $!\n";
2364
2365 for (1..2) {
2366 8 == sysread $fh, my $buf, 8
2367 or die "timerfd read failure\n";
2368
2369 printf "number of expirations (likely 1): %d\n",
2370 unpack "Q", $buf;
2371 }
2372
2373=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2374
2375This is a direct interface to the Linux L<timerfd_settime(2)> system
2376call. Please refer to its manpage for more info on this call.
2377
2378The new itimerspec is specified using two (possibly fractional) second
2379values, C<$new_interval> and C<$new_value>).
2380
2381On success, the current interval and value are returned (as per
2382C<timerfd_gettime>). On failure, the empty list is returned.
2383
2384The following C<$flags> values are
2385available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2386C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2387
2388See C<IO::AIO::timerfd_create> for a full example.
2389
2390=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2391
2392This is a direct interface to the Linux L<timerfd_gettime(2)> system
2393call. Please refer to its manpage for more info on this call.
2394
2395On success, returns the current values of interval and value for the given
2396timerfd (as potentially fractional second values). On failure, the empty
2397list is returned.
2161 2398
2162=back 2399=back
2163 2400
2164=cut 2401=cut
2165 2402
… …
2231the process will result in undefined behaviour. Calling it at any time 2468the process will result in undefined behaviour. Calling it at any time
2232will also result in any undefined (by POSIX) behaviour. 2469will also result in any undefined (by POSIX) behaviour.
2233 2470
2234=back 2471=back
2235 2472
2473=head2 LINUX-SPECIFIC CALLS
2474
2475When a call is documented as "linux-specific" then this means it
2476originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2477availability and compatibility of such calls regardless of the platform
2478it is compiled on, so platforms such as FreeBSD which often implement
2479these calls will work. When in doubt, call them and see if they fail wth
2480C<ENOSYS>.
2481
2236=head2 MEMORY USAGE 2482=head2 MEMORY USAGE
2237 2483
2238Per-request usage: 2484Per-request usage:
2239 2485
2240Each aio request uses - depending on your architecture - around 100-200 2486Each aio request uses - depending on your architecture - around 100-200
… …
2252temporary buffers, and each thread requires a stack and other data 2498temporary buffers, and each thread requires a stack and other data
2253structures (usually around 16k-128k, depending on the OS). 2499structures (usually around 16k-128k, depending on the OS).
2254 2500
2255=head1 KNOWN BUGS 2501=head1 KNOWN BUGS
2256 2502
2257Known bugs will be fixed in the next release. 2503Known bugs will be fixed in the next release :)
2504
2505=head1 KNOWN ISSUES
2506
2507Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2508or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2509non-created hash slots or other scalars I didn't think of. It's best to
2510avoid such and either use scalar variables or making sure that the scalar
2511exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2512
2513I am not sure anything can be done about this, so this is considered a
2514known issue, rather than a bug.
2258 2515
2259=head1 SEE ALSO 2516=head1 SEE ALSO
2260 2517
2261L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2518L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2262more natural syntax. 2519more natural syntax.

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