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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.264 by root, Mon Jul 18 07:48:01 2016 UTC vs.
Revision 1.302 by root, Wed Apr 3 03:03:53 2019 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 = 4.34; 176 our $VERSION = 4.72;
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_fcntl aio_ioctl 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
177 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
178 aio_pathsync aio_readahead aio_fiemap aio_allocate 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
… …
248 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
249 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
250 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
251 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
252 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
253 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
254 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
255 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
256 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
257 aio_group $callback->(...) 263 aio_group $callback->(...)
258 aio_nop $callback->() 264 aio_nop $callback->()
… …
272 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
273 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
274 IO::AIO::nreqs 280 IO::AIO::nreqs
275 IO::AIO::nready 281 IO::AIO::nready
276 IO::AIO::npending 282 IO::AIO::npending
283 IO::AIO::reinit
284
285 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
286 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
277 287
278 IO::AIO::sendfile $ofh, $ifh, $offset, $count 288 IO::AIO::sendfile $ofh, $ifh, $offset, $count
279 IO::AIO::fadvise $fh, $offset, $len, $advice 289 IO::AIO::fadvise $fh, $offset, $len, $advice
290
280 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 291 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
281 IO::AIO::munmap $scalar 292 IO::AIO::munmap $scalar
293 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
282 IO::AIO::madvise $scalar, $offset, $length, $advice 294 IO::AIO::madvise $scalar, $offset, $length, $advice
283 IO::AIO::mprotect $scalar, $offset, $length, $protect 295 IO::AIO::mprotect $scalar, $offset, $length, $protect
284 IO::AIO::munlock $scalar, $offset = 0, $length = undef 296 IO::AIO::munlock $scalar, $offset = 0, $length = undef
285 IO::AIO::munlockall 297 IO::AIO::munlockall
298
299 # stat extensions
300 $counter = IO::AIO::st_gen
301 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
302 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
303 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
304 $seconds = IO::AIO::st_btimesec
305 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
306
307 # very much unportable syscalls
308 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
309 IO::AIO::tee $r_fh, $w_fh, $length, $flags
310 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
311 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
312 $fh = IO::AIO::memfd_create $pathname[, $flags]
313 $fh = IO::AIO::eventfd [$initval, [$flags]]
314 $fh = IO::AIO::timerfd_create $clockid[, $flags]
315 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
316 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
286 317
287=head2 API NOTES 318=head2 API NOTES
288 319
289All the C<aio_*> calls are more or less thin wrappers around the syscall 320All the C<aio_*> calls are more or less thin wrappers around the syscall
290with the same name (sans C<aio_>). The arguments are similar or identical, 321with the same name (sans C<aio_>). The arguments are similar or identical,
… …
396following POSIX and non-POSIX constants are available (missing ones on 427following POSIX and non-POSIX constants are available (missing ones on
397your system are, as usual, C<0>): 428your system are, as usual, C<0>):
398 429
399C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 430C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
400C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 431C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
401C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>. 432C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
402 433
403 434
404=item aio_close $fh, $callback->($status) 435=item aio_close $fh, $callback->($status)
405 436
406Asynchronously close a file and call the callback with the result 437Asynchronously close a file and call the callback with the result
… …
441=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 472=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
442 473
443=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 474=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
444 475
445Reads or writes C<$length> bytes from or to the specified C<$fh> and 476Reads or writes C<$length> bytes from or to the specified C<$fh> and
446C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 477C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
447and calls the callback without the actual number of bytes read (or -1 on 478calls the callback with the actual number of bytes transferred (or -1 on
448error, just like the syscall). 479error, just like the syscall).
449 480
450C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 481C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
451offset plus the actual number of bytes read. 482offset plus the actual number of bytes read.
452 483
… …
532 563
533=item aio_stat $fh_or_path, $callback->($status) 564=item aio_stat $fh_or_path, $callback->($status)
534 565
535=item aio_lstat $fh, $callback->($status) 566=item aio_lstat $fh, $callback->($status)
536 567
537Works like perl's C<stat> or C<lstat> in void context. The callback will 568Works almost exactly like perl's C<stat> or C<lstat> in void context. The
538be called after the stat and the results will be available using C<stat _> 569callback will be called after the stat and the results will be available
539or C<-s _> etc... 570using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
571and C<-T>).
540 572
541The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 573The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
542for an explanation. 574for an explanation.
543 575
544Currently, the stats are always 64-bit-stats, i.e. instead of returning an 576Currently, the stats are always 64-bit-stats, i.e. instead of returning an
… …
551behaviour). 583behaviour).
552 584
553C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 585C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
554C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, 586C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
555C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. 587C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
588
589To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
590ACCESS>.
556 591
557Example: Print the length of F</etc/passwd>: 592Example: Print the length of F</etc/passwd>:
558 593
559 aio_stat "/etc/passwd", sub { 594 aio_stat "/etc/passwd", sub {
560 $_[0] and die "stat failed: $!"; 595 $_[0] and die "stat failed: $!";
… …
604 namemax => 255, 639 namemax => 255,
605 frsize => 1024, 640 frsize => 1024,
606 fsid => 1810 641 fsid => 1810
607 } 642 }
608 643
609Here is a (likely partial - send me updates!) list of fsid values used by
610Linux - it is safe to hardcode these when C<$^O> is C<linux>:
611
612 0x0000adf5 adfs
613 0x0000adff affs
614 0x5346414f afs
615 0x09041934 anon-inode filesystem
616 0x00000187 autofs
617 0x42465331 befs
618 0x1badface bfs
619 0x42494e4d binfmt_misc
620 0x9123683e btrfs
621 0x0027e0eb cgroupfs
622 0xff534d42 cifs
623 0x73757245 coda
624 0x012ff7b7 coh
625 0x28cd3d45 cramfs
626 0x453dcd28 cramfs-wend (wrong endianness)
627 0x64626720 debugfs
628 0x00001373 devfs
629 0x00001cd1 devpts
630 0x0000f15f ecryptfs
631 0x00414a53 efs
632 0x0000137d ext
633 0x0000ef53 ext2/ext3/ext4
634 0x0000ef51 ext2
635 0xf2f52010 f2fs
636 0x00004006 fat
637 0x65735546 fuseblk
638 0x65735543 fusectl
639 0x0bad1dea futexfs
640 0x01161970 gfs2
641 0x47504653 gpfs
642 0x00004244 hfs
643 0xf995e849 hpfs
644 0x00c0ffee hostfs
645 0x958458f6 hugetlbfs
646 0x2bad1dea inotifyfs
647 0x00009660 isofs
648 0x000072b6 jffs2
649 0x3153464a jfs
650 0x6b414653 k-afs
651 0x0bd00bd0 lustre
652 0x0000137f minix
653 0x0000138f minix 30 char names
654 0x00002468 minix v2
655 0x00002478 minix v2 30 char names
656 0x00004d5a minix v3
657 0x19800202 mqueue
658 0x00004d44 msdos
659 0x0000564c novell
660 0x00006969 nfs
661 0x6e667364 nfsd
662 0x00003434 nilfs
663 0x5346544e ntfs
664 0x00009fa1 openprom
665 0x7461636F ocfs2
666 0x00009fa0 proc
667 0x6165676c pstorefs
668 0x0000002f qnx4
669 0x68191122 qnx6
670 0x858458f6 ramfs
671 0x52654973 reiserfs
672 0x00007275 romfs
673 0x67596969 rpc_pipefs
674 0x73636673 securityfs
675 0xf97cff8c selinux
676 0x0000517b smb
677 0x534f434b sockfs
678 0x73717368 squashfs
679 0x62656572 sysfs
680 0x012ff7b6 sysv2
681 0x012ff7b5 sysv4
682 0x01021994 tmpfs
683 0x15013346 udf
684 0x00011954 ufs
685 0x54190100 ufs byteswapped
686 0x00009fa2 usbdevfs
687 0x01021997 v9fs
688 0xa501fcf5 vxfs
689 0xabba1974 xenfs
690 0x012ff7b4 xenix
691 0x58465342 xfs
692 0x012fd16d xia
693
694=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 644=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
695 645
696Works like perl's C<utime> function (including the special case of $atime 646Works like perl's C<utime> function (including the special case of $atime
697and $mtime being undef). Fractional times are supported if the underlying 647and $mtime being undef). Fractional times are supported if the underlying
698syscalls support them. 648syscalls support them.
699 649
700When called with a pathname, uses utimes(2) if available, otherwise 650When called with a pathname, uses utimensat(2) or utimes(2) if available,
701utime(2). If called on a file descriptor, uses futimes(2) if available, 651otherwise utime(2). If called on a file descriptor, uses futimens(2)
702otherwise returns ENOSYS, so this is not portable. 652or futimes(2) if available, otherwise returns ENOSYS, so this is not
653portable.
703 654
704Examples: 655Examples:
705 656
706 # set atime and mtime to current time (basically touch(1)): 657 # set atime and mtime to current time (basically touch(1)):
707 aio_utime "path", undef, undef; 658 aio_utime "path", undef, undef;
… …
735C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate 686C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
736space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>, 687space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
737to deallocate a file range. 688to deallocate a file range.
738 689
739IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range 690IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
740(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see 691(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
741your L<fallocate(2)> manpage). 692C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
693to unshare shared blocks (see your L<fallocate(2)> manpage).
742 694
743The file system block size used by C<fallocate> is presumably the 695The file system block size used by C<fallocate> is presumably the
744C<f_bsize> returned by C<statvfs>. 696C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
697can dictate other limitations.
745 698
746If C<fallocate> isn't available or cannot be emulated (currently no 699If C<fallocate> isn't available or cannot be emulated (currently no
747emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 700emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
748 701
749 702
… …
808On systems that support the AIO::WD working directory abstraction 761On systems that support the AIO::WD working directory abstraction
809natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 762natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
810of failing, C<rename> is called on the absolute path of C<$wd>. 763of failing, C<rename> is called on the absolute path of C<$wd>.
811 764
812 765
766=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
767
768Basically a version of C<aio_rename> with an additional C<$flags>
769argument. Calling this with C<$flags=0> is the same as calling
770C<aio_rename>.
771
772Non-zero flags are currently only supported on GNU/Linux systems that
773support renameat2. Other systems fail with C<ENOSYS> in this case.
774
775The following constants are available (missing ones are, as usual C<0>),
776see renameat2(2) for details:
777
778C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
779and C<IO::AIO::RENAME_WHITEOUT>.
780
781
813=item aio_mkdir $pathname, $mode, $callback->($status) 782=item aio_mkdir $pathname, $mode, $callback->($status)
814 783
815Asynchronously mkdir (create) a directory and call the callback with 784Asynchronously mkdir (create) a directory and call the callback with
816the result code. C<$mode> will be modified by the umask at the time the 785the result code. C<$mode> will be modified by the umask at the time the
817request is executed, so do not change your umask. 786request is executed, so do not change your umask.
… …
848 817
849=over 4 818=over 4
850 819
851=item IO::AIO::READDIR_DENTS 820=item IO::AIO::READDIR_DENTS
852 821
853When this flag is off, then the callback gets an arrayref consisting of 822Normally the callback gets an arrayref consisting of names only (as
854names only (as with C<aio_readdir>), otherwise it gets an arrayref with 823with C<aio_readdir>). If this flag is set, then the callback gets an
855C<[$name, $type, $inode]> arrayrefs, each describing a single directory 824arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
856entry in more detail. 825single directory entry in more detail:
857 826
858C<$name> is the name of the entry. 827C<$name> is the name of the entry.
859 828
860C<$type> is one of the C<IO::AIO::DT_xxx> constants: 829C<$type> is one of the C<IO::AIO::DT_xxx> constants:
861 830
862C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 831C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
863C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 832C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
864C<IO::AIO::DT_WHT>. 833C<IO::AIO::DT_WHT>.
865 834
866C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 835C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
867know, you have to run stat yourself. Also, for speed reasons, the C<$type> 836to know, you have to run stat yourself. Also, for speed/memory reasons,
868scalars are read-only: you can not modify them. 837the C<$type> scalars are read-only: you must not modify them.
869 838
870C<$inode> is the inode number (which might not be exact on systems with 64 839C<$inode> is the inode number (which might not be exact on systems with 64
871bit inode numbers and 32 bit perls). This field has unspecified content on 840bit inode numbers and 32 bit perls). This field has unspecified content on
872systems that do not deliver the inode information. 841systems that do not deliver the inode information.
873 842
… …
884short names are tried first. 853short names are tried first.
885 854
886=item IO::AIO::READDIR_STAT_ORDER 855=item IO::AIO::READDIR_STAT_ORDER
887 856
888When this flag is set, then the names will be returned in an order 857When this flag is set, then the names will be returned in an order
889suitable for stat()'ing each one. That is, when you plan to stat() 858suitable for stat()'ing each one. That is, when you plan to stat() most or
890all files in the given directory, then the returned order will likely 859all files in the given directory, then the returned order will likely be
891be fastest. 860faster.
892 861
893If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 862If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
894the likely dirs come first, resulting in a less optimal stat order. 863then the likely dirs come first, resulting in a less optimal stat order
864for stat'ing all entries, but likely a more optimal order for finding
865subdirectories.
895 866
896=item IO::AIO::READDIR_FOUND_UNKNOWN 867=item IO::AIO::READDIR_FOUND_UNKNOWN
897 868
898This flag should not be set when calling C<aio_readdirx>. Instead, it 869This flag should not be set when calling C<aio_readdirx>. Instead, it
899is being set by C<aio_readdirx>, when any of the C<$type>'s found were 870is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
901C<$type>'s are known, which can be used to speed up some algorithms. 872C<$type>'s are known, which can be used to speed up some algorithms.
902 873
903=back 874=back
904 875
905 876
877=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
878
879Opens, reads and closes the given file. The data is put into C<$data>,
880which is resized as required.
881
882If C<$offset> is negative, then it is counted from the end of the file.
883
884If C<$length> is zero, then the remaining length of the file is
885used. Also, in this case, the same limitations to modifying C<$data> apply
886as when IO::AIO::mmap is used, i.e. it must only be modified in-place
887with C<substr>. If the size of the file is known, specifying a non-zero
888C<$length> results in a performance advantage.
889
890This request is similar to the older C<aio_load> request, but since it is
891a single request, it might be more efficient to use.
892
893Example: load F</etc/passwd> into C<$passwd>.
894
895 my $passwd;
896 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
897 $_[0] >= 0
898 or die "/etc/passwd: $!\n";
899
900 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
901 print $passwd;
902 };
903 IO::AIO::flush;
904
905
906=item aio_load $pathname, $data, $callback->($status) 906=item aio_load $pathname, $data, $callback->($status)
907 907
908This is a composite request that tries to fully load the given file into 908This is a composite request that tries to fully load the given file into
909memory. Status is the same as with aio_read. 909memory. Status is the same as with aio_read.
910
911Using C<aio_slurp> might be more efficient, as it is a single request.
910 912
911=cut 913=cut
912 914
913sub aio_load($$;$) { 915sub aio_load($$;$) {
914 my ($path, undef, $cb) = @_; 916 my ($path, undef, $cb) = @_;
… …
934=item aio_copy $srcpath, $dstpath, $callback->($status) 936=item aio_copy $srcpath, $dstpath, $callback->($status)
935 937
936Try to copy the I<file> (directories not supported as either source or 938Try to copy the I<file> (directories not supported as either source or
937destination) from C<$srcpath> to C<$dstpath> and call the callback with 939destination) from C<$srcpath> to C<$dstpath> and call the callback with
938a status of C<0> (ok) or C<-1> (error, see C<$!>). 940a status of C<0> (ok) or C<-1> (error, see C<$!>).
941
942Existing destination files will be truncated.
939 943
940This is a composite request that creates the destination file with 944This is a composite request that creates the destination file with
941mode 0200 and copies the contents of the source file into it using 945mode 0200 and copies the contents of the source file into it using
942C<aio_sendfile>, followed by restoring atime, mtime, access mode and 946C<aio_sendfile>, followed by restoring atime, mtime, access mode and
943uid/gid, in that order. 947uid/gid, in that order.
… …
1053Scans a directory (similar to C<aio_readdir>) but additionally tries to 1057Scans a directory (similar to C<aio_readdir>) but additionally tries to
1054efficiently separate the entries of directory C<$path> into two sets of 1058efficiently separate the entries of directory C<$path> into two sets of
1055names, directories you can recurse into (directories), and ones you cannot 1059names, directories you can recurse into (directories), and ones you cannot
1056recurse into (everything else, including symlinks to directories). 1060recurse into (everything else, including symlinks to directories).
1057 1061
1058C<aio_scandir> is a composite request that creates of many sub requests_ 1062C<aio_scandir> is a composite request that generates many sub requests.
1059C<$maxreq> specifies the maximum number of outstanding aio requests that 1063C<$maxreq> specifies the maximum number of outstanding aio requests that
1060this function generates. If it is C<< <= 0 >>, then a suitable default 1064this function generates. If it is C<< <= 0 >>, then a suitable default
1061will be chosen (currently 4). 1065will be chosen (currently 4).
1062 1066
1063On error, the callback is called without arguments, otherwise it receives 1067On error, the callback is called without arguments, otherwise it receives
… …
1127 aioreq_pri $pri; 1131 aioreq_pri $pri;
1128 add $grp aio_stat $wd, sub { 1132 add $grp aio_stat $wd, sub {
1129 return $grp->result () if $_[0]; 1133 return $grp->result () if $_[0];
1130 my $now = time; 1134 my $now = time;
1131 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1135 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1136 my $rdxflags = READDIR_DIRS_FIRST;
1137
1138 if ((stat _)[3] < 2) {
1139 # at least one non-POSIX filesystem exists
1140 # that returns useful DT_type values: btrfs,
1141 # so optimise for this here by requesting dents
1142 $rdxflags |= READDIR_DENTS;
1143 }
1132 1144
1133 # read the directory entries 1145 # read the directory entries
1134 aioreq_pri $pri; 1146 aioreq_pri $pri;
1135 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1147 add $grp aio_readdirx $wd, $rdxflags, sub {
1136 my $entries = shift 1148 my ($entries, $flags) = @_
1137 or return $grp->result (); 1149 or return $grp->result ();
1150
1151 if ($rdxflags & READDIR_DENTS) {
1152 # if we requested type values, see if we can use them directly.
1153
1154 # if there were any DT_UNKNOWN entries then we assume we
1155 # don't know. alternatively, we could assume that if we get
1156 # one DT_DIR, then all directories are indeed marked with
1157 # DT_DIR, but this seems not required for btrfs, and this
1158 # is basically the "btrfs can't get it's act together" code
1159 # branch.
1160 unless ($flags & READDIR_FOUND_UNKNOWN) {
1161 # now we have valid DT_ information for all entries,
1162 # so use it as an optimisation without further stat's.
1163 # they must also all be at the beginning of @$entries
1164 # by now.
1165
1166 my $dirs;
1167
1168 if (@$entries) {
1169 for (0 .. $#$entries) {
1170 if ($entries->[$_][1] != DT_DIR) {
1171 # splice out directories
1172 $dirs = [splice @$entries, 0, $_];
1173 last;
1174 }
1175 }
1176
1177 # if we didn't find any non-dir, then all entries are dirs
1178 unless ($dirs) {
1179 ($dirs, $entries) = ($entries, []);
1180 }
1181 } else {
1182 # directory is empty, so there are no sbdirs
1183 $dirs = [];
1184 }
1185
1186 # either splice'd the directories out or the dir was empty.
1187 # convert dents to filenames
1188 $_ = $_->[0] for @$dirs;
1189 $_ = $_->[0] for @$entries;
1190
1191 return $grp->result ($dirs, $entries);
1192 }
1193
1194 # cannot use, so return to our old ways
1195 # by pretending we only scanned for names.
1196 $_ = $_->[0] for @$entries;
1197 }
1138 1198
1139 # stat the dir another time 1199 # stat the dir another time
1140 aioreq_pri $pri; 1200 aioreq_pri $pri;
1141 add $grp aio_stat $wd, sub { 1201 add $grp aio_stat $wd, sub {
1142 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1202 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1250other processes), although if you are careful and know what you are doing, 1310other processes), although if you are careful and know what you are doing,
1251you still can. 1311you still can.
1252 1312
1253The following constants are available (missing ones are, as usual C<0>): 1313The following constants are available (missing ones are, as usual C<0>):
1254 1314
1315C<F_DUPFD_CLOEXEC>,
1316
1317C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1318
1255C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>. 1319C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1256 1320
1257C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>, 1321C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1258C<FS_IOC_FIEMAP>. 1322C<FS_IOC_FIEMAP>.
1259 1323
… …
1346 }; 1410 };
1347 1411
1348 $grp 1412 $grp
1349} 1413}
1350 1414
1351=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1415=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1352 1416
1353This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1417This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1354scalars (see the C<IO::AIO::mmap> function, although it also works on data 1418scalars (see the C<IO::AIO::mmap> function, although it also works on data
1355scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1419scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1356scalar must only be modified in-place while an aio operation is pending on 1420scalar must only be modified in-place while an aio operation is pending on
… …
1358 1422
1359It calls the C<msync> function of your OS, if available, with the memory 1423It calls the C<msync> function of your OS, if available, with the memory
1360area starting at C<$offset> in the string and ending C<$length> bytes 1424area starting at C<$offset> in the string and ending C<$length> bytes
1361later. If C<$length> is negative, counts from the end, and if C<$length> 1425later. If C<$length> is negative, counts from the end, and if C<$length>
1362is C<undef>, then it goes till the end of the string. The flags can be 1426is C<undef>, then it goes till the end of the string. The flags can be
1363a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1427either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1364C<IO::AIO::MS_SYNC>. 1428C<IO::AIO::MS_INVALIDATE>.
1365 1429
1366=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1430=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1367 1431
1368This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1432This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1369scalars. 1433scalars.
… …
1399 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1463 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1400 aio_mlock $data; # mlock in background 1464 aio_mlock $data; # mlock in background
1401 1465
1402=item aio_mlockall $flags, $callback->($status) 1466=item aio_mlockall $flags, $callback->($status)
1403 1467
1404Calls the C<mlockall> function with the given C<$flags> (a combination of 1468Calls the C<mlockall> function with the given C<$flags> (a
1405C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1469combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1470C<IO::AIO::MCL_ONFAULT>).
1406 1471
1407On systems that do not implement C<mlockall>, this function returns C<-1> 1472On systems that do not implement C<mlockall>, this function returns C<-1>
1408and sets errno to C<ENOSYS>. 1473and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1474by the system result in a return value of C<-1> with errno being set to
1475C<EINVAL>.
1409 1476
1410Note that the corresponding C<munlockall> is synchronous and is 1477Note that the corresponding C<munlockall> is synchronous and is
1411documented under L<MISCELLANEOUS FUNCTIONS>. 1478documented under L<MISCELLANEOUS FUNCTIONS>.
1412 1479
1413Example: asynchronously lock all current and future pages into memory. 1480Example: asynchronously lock all current and future pages into memory.
… …
1452C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1519C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1453C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1520C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1454C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1521C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1455C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1522C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1456 1523
1457At the time of this writing (Linux 3.2), this requets is unreliable unless 1524At the time of this writing (Linux 3.2), this request is unreliable unless
1458C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1525C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1459it to return all extents of a range for files with large number of 1526it to return all extents of a range for files with a large number of
1460extents. The code works around all these issues if C<$count> is undef. 1527extents. The code (only) works around all these issues if C<$count> is
1528C<undef>.
1461 1529
1462=item aio_group $callback->(...) 1530=item aio_group $callback->(...)
1463 1531
1464This is a very special aio request: Instead of doing something, it is a 1532This is a very special aio request: Instead of doing something, it is a
1465container for other aio requests, which is useful if you want to bundle 1533container for other aio requests, which is useful if you want to bundle
… …
1578There are some caveats: when directories get renamed (or deleted), the 1646There are some caveats: when directories get renamed (or deleted), the
1579pathname string doesn't change, so will point to the new directory (or 1647pathname string doesn't change, so will point to the new directory (or
1580nowhere at all), while the directory fd, if available on the system, 1648nowhere at all), while the directory fd, if available on the system,
1581will still point to the original directory. Most functions accepting a 1649will still point to the original directory. Most functions accepting a
1582pathname will use the directory fd on newer systems, and the string on 1650pathname will use the directory fd on newer systems, and the string on
1583older systems. Some functions (such as realpath) will always rely on the 1651older systems. Some functions (such as C<aio_realpath>) will always rely on
1584string form of the pathname. 1652the string form of the pathname.
1585 1653
1586So this functionality is mainly useful to get some protection against 1654So this functionality is mainly useful to get some protection against
1587C<chdir>, to easily get an absolute path out of a relative path for future 1655C<chdir>, to easily get an absolute path out of a relative path for future
1588reference, and to speed up doing many operations in the same directory 1656reference, and to speed up doing many operations in the same directory
1589(e.g. when stat'ing all files in a directory). 1657(e.g. when stat'ing all files in a directory).
… …
1797The default value for the limit is C<0>, but note that setting a feeder 1865The default value for the limit is C<0>, but note that setting a feeder
1798automatically bumps it up to C<2>. 1866automatically bumps it up to C<2>.
1799 1867
1800=back 1868=back
1801 1869
1870
1802=head2 SUPPORT FUNCTIONS 1871=head2 SUPPORT FUNCTIONS
1803 1872
1804=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1873=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1805 1874
1806=over 4 1875=over 4
… …
1871Strictly equivalent to: 1940Strictly equivalent to:
1872 1941
1873 IO::AIO::poll_wait, IO::AIO::poll_cb 1942 IO::AIO::poll_wait, IO::AIO::poll_cb
1874 while IO::AIO::nreqs; 1943 while IO::AIO::nreqs;
1875 1944
1945This function can be useful at program aborts, to make sure outstanding
1946I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1947this function on normal exits), or when you are merely using C<IO::AIO>
1948for its more advanced functions, rather than for async I/O, e.g.:
1949
1950 my ($dirs, $nondirs);
1951 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1952 IO::AIO::flush;
1953 # $dirs, $nondirs are now set
1954
1876=item IO::AIO::max_poll_reqs $nreqs 1955=item IO::AIO::max_poll_reqs $nreqs
1877 1956
1878=item IO::AIO::max_poll_time $seconds 1957=item IO::AIO::max_poll_time $seconds
1879 1958
1880These set the maximum number of requests (default C<0>, meaning infinity) 1959These set the maximum number of requests (default C<0>, meaning infinity)
… …
1906 poll => 'r', nice => 1, 1985 poll => 'r', nice => 1,
1907 cb => &IO::AIO::poll_cb); 1986 cb => &IO::AIO::poll_cb);
1908 1987
1909=back 1988=back
1910 1989
1990
1911=head3 CONTROLLING THE NUMBER OF THREADS 1991=head3 CONTROLLING THE NUMBER OF THREADS
1912 1992
1913=over 1993=over
1914 1994
1915=item IO::AIO::min_parallel $nthreads 1995=item IO::AIO::min_parallel $nthreads
… …
1981This is a very bad function to use in interactive programs because it 2061This is a very bad function to use in interactive programs because it
1982blocks, and a bad way to reduce concurrency because it is inexact: Better 2062blocks, and a bad way to reduce concurrency because it is inexact: Better
1983use an C<aio_group> together with a feed callback. 2063use an C<aio_group> together with a feed callback.
1984 2064
1985Its main use is in scripts without an event loop - when you want to stat 2065Its main use is in scripts without an event loop - when you want to stat
1986a lot of files, you can write somehting like this: 2066a lot of files, you can write something like this:
1987 2067
1988 IO::AIO::max_outstanding 32; 2068 IO::AIO::max_outstanding 32;
1989 2069
1990 for my $path (...) { 2070 for my $path (...) {
1991 aio_stat $path , ...; 2071 aio_stat $path , ...;
… …
2002The default value for C<max_outstanding> is very large, so there is no 2082The default value for C<max_outstanding> is very large, so there is no
2003practical limit on the number of outstanding requests. 2083practical limit on the number of outstanding requests.
2004 2084
2005=back 2085=back
2006 2086
2087
2007=head3 STATISTICAL INFORMATION 2088=head3 STATISTICAL INFORMATION
2008 2089
2009=over 2090=over
2010 2091
2011=item IO::AIO::nreqs 2092=item IO::AIO::nreqs
… …
2027 2108
2028Returns the number of requests currently in the pending state (executed, 2109Returns the number of requests currently in the pending state (executed,
2029but not yet processed by poll_cb). 2110but not yet processed by poll_cb).
2030 2111
2031=back 2112=back
2113
2114
2115=head3 SUBSECOND STAT TIME ACCESS
2116
2117Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2118generally find access/modification and change times with subsecond time
2119accuracy of the system supports it, but perl's built-in functions only
2120return the integer part.
2121
2122The following functions return the timestamps of the most recent
2123stat with subsecond precision on most systems and work both after
2124C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2125value is only meaningful after a successful C<stat>/C<lstat> call, or
2126during/after a successful C<aio_stat>/C<aio_lstat> callback.
2127
2128This is similar to the L<Time::HiRes> C<stat> functions, but can return
2129full resolution without rounding and work with standard perl C<stat>,
2130alleviating the need to call the special C<Time::HiRes> functions, which
2131do not act like their perl counterparts.
2132
2133On operating systems or file systems where subsecond time resolution is
2134not supported or could not be detected, a fractional part of C<0> is
2135returned, so it is always safe to call these functions.
2136
2137=over 4
2138
2139=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2140
2141Return the access, modication, change or birth time, respectively,
2142including fractional part. Due to the limited precision of floating point,
2143the accuracy on most platforms is only a bit better than milliseconds
2144for times around now - see the I<nsec> function family, below, for full
2145accuracy.
2146
2147File birth time is only available when the OS and perl support it (on
2148FreeBSD and NetBSD at the time of this writing, although support is
2149adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
2150it). On systems where it isn't available, C<0> is currently returned, but
2151this might change to C<undef> in a future version.
2152
2153=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2154
2155Returns access, modification, change and birth time all in one go, and
2156maybe more times in the future version.
2157
2158=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2159
2160Return the fractional access, modifcation, change or birth time, in nanoseconds,
2161as an integer in the range C<0> to C<999999999>.
2162
2163Note that no accessors are provided for access, modification and
2164change times - you need to get those from C<stat _> if required (C<int
2165IO::AIO::st_atime> and so on will I<not> generally give you the correct
2166value).
2167
2168=item $seconds = IO::AIO::st_btimesec
2169
2170The (integral) seconds part of the file birth time, if available.
2171
2172=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2173
2174Like the functions above, but returns all four times in one go (and maybe
2175more in future versions).
2176
2177=item $counter = IO::AIO::st_gen
2178
2179Returns the generation counter (in practice this is just a random number)
2180of the file. This is only available on platforms which have this member in
2181their C<struct stat> (most BSDs at the time of this writing) and generally
2182only to the root usert. If unsupported, C<0> is returned, but this might
2183change to C<undef> in a future version.
2184
2185=back
2186
2187Example: print the high resolution modification time of F</etc>, using
2188C<stat>, and C<IO::AIO::aio_stat>.
2189
2190 if (stat "/etc") {
2191 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2192 }
2193
2194 IO::AIO::aio_stat "/etc", sub {
2195 $_[0]
2196 and return;
2197
2198 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2199 };
2200
2201 IO::AIO::flush;
2202
2203Output of the awbove on my system, showing reduced and full accuracy:
2204
2205 stat(/etc) mtime: 1534043702.020808
2206 aio_stat(/etc) mtime: 1534043702.020807792
2207
2032 2208
2033=head3 MISCELLANEOUS FUNCTIONS 2209=head3 MISCELLANEOUS FUNCTIONS
2034 2210
2035IO::AIO implements some functions that are useful when you want to use 2211IO::AIO implements some functions that are useful when you want to use
2036some "Advanced I/O" function not available to in Perl, without going the 2212some "Advanced I/O" function not available to in Perl, without going the
2037"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*> 2213"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2038counterpart. 2214counterpart.
2039 2215
2040=over 4 2216=over 4
2217
2218=item $numfd = IO::AIO::get_fdlimit
2219
2220This function is I<EXPERIMENTAL> and subject to change.
2221
2222Tries to find the current file descriptor limit and returns it, or
2223C<undef> and sets C<$!> in case of an error. The limit is one larger than
2224the highest valid file descriptor number.
2225
2226=item IO::AIO::min_fdlimit [$numfd]
2227
2228This function is I<EXPERIMENTAL> and subject to change.
2229
2230Try to increase the current file descriptor limit(s) to at least C<$numfd>
2231by changing the soft or hard file descriptor resource limit. If C<$numfd>
2232is missing, it will try to set a very high limit, although this is not
2233recommended when you know the actual minimum that you require.
2234
2235If the limit cannot be raised enough, the function makes a best-effort
2236attempt to increase the limit as much as possible, using various
2237tricks, while still failing. You can query the resulting limit using
2238C<IO::AIO::get_fdlimit>.
2239
2240If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2241true.
2041 2242
2042=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2243=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
2043 2244
2044Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2245Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
2045but is blocking (this makes most sense if you know the input data is 2246but is blocking (this makes most sense if you know the input data is
… …
2062=item IO::AIO::madvise $scalar, $offset, $len, $advice 2263=item IO::AIO::madvise $scalar, $offset, $len, $advice
2063 2264
2064Simply calls the C<posix_madvise> function (see its 2265Simply calls the C<posix_madvise> function (see its
2065manpage for details). The following advice constants are 2266manpage for details). The following advice constants are
2066available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2267available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2067C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>, 2268C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2068C<IO::AIO::MADV_FREE>. 2269C<IO::AIO::MADV_DONTNEED>.
2270
2271If C<$offset> is negative, counts from the end. If C<$length> is negative,
2272the remaining length of the C<$scalar> is used. If possible, C<$length>
2273will be reduced to fit into the C<$scalar>.
2069 2274
2070On systems that do not implement C<posix_madvise>, this function returns 2275On systems that do not implement C<posix_madvise>, this function returns
2071ENOSYS, otherwise the return value of C<posix_madvise>. 2276ENOSYS, otherwise the return value of C<posix_madvise>.
2072 2277
2073=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2278=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2075Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2280Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2076$scalar (see its manpage for details). The following protect 2281$scalar (see its manpage for details). The following protect
2077constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2282constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2078C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2283C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2079 2284
2285If C<$offset> is negative, counts from the end. If C<$length> is negative,
2286the remaining length of the C<$scalar> is used. If possible, C<$length>
2287will be reduced to fit into the C<$scalar>.
2288
2080On systems that do not implement C<mprotect>, this function returns 2289On systems that do not implement C<mprotect>, this function returns
2081ENOSYS, otherwise the return value of C<mprotect>. 2290ENOSYS, otherwise the return value of C<mprotect>.
2082 2291
2083=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2292=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2084 2293
2085Memory-maps a file (or anonymous memory range) and attaches it to the 2294Memory-maps a file (or anonymous memory range) and attaches it to the
2086given C<$scalar>, which will act like a string scalar. Returns true on 2295given C<$scalar>, which will act like a string scalar. Returns true on
2087success, and false otherwise. 2296success, and false otherwise.
2088 2297
2298The scalar must exist, but its contents do not matter - this means you
2299cannot use a nonexistant array or hash element. When in doubt, C<undef>
2300the scalar first.
2301
2089The only operations allowed on the scalar are C<substr>/C<vec> that don't 2302The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2090change the string length, and most read-only operations such as copying it 2303which don't change the string length, and most read-only operations such
2091or searching it with regexes and so on. 2304as copying it or searching it with regexes and so on.
2092 2305
2093Anything else is unsafe and will, at best, result in memory leaks. 2306Anything else is unsafe and will, at best, result in memory leaks.
2094 2307
2095The memory map associated with the C<$scalar> is automatically removed 2308The memory map associated with the C<$scalar> is automatically removed
2096when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2309when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2097C<IO::AIO::munmap> functions are called. 2310or C<IO::AIO::munmap> functions are called on it.
2098 2311
2099This calls the C<mmap>(2) function internally. See your system's manual 2312This calls the C<mmap>(2) function internally. See your system's manual
2100page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2313page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2101 2314
2102The C<$length> must be larger than zero and smaller than the actual 2315The C<$length> must be larger than zero and smaller than the actual
… …
2140 2353
2141=item IO::AIO::munmap $scalar 2354=item IO::AIO::munmap $scalar
2142 2355
2143Removes a previous mmap and undefines the C<$scalar>. 2356Removes a previous mmap and undefines the C<$scalar>.
2144 2357
2358=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2359
2360Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2361been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2362C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2363
2364Returns true if successful, and false otherwise. If the underlying mmapped
2365region has changed address, then the true value has the numerical value
2366C<1>, otherwise it has the numerical value C<0>:
2367
2368 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2369 or die "mremap: $!";
2370
2371 if ($success*1) {
2372 warn "scalar has chanegd address in memory\n";
2373 }
2374
2375C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2376implemented, but not supported and might go away in a future version.
2377
2378On systems where this call is not supported or is not emulated, this call
2379returns falls and sets C<$!> to C<ENOSYS>.
2380
2381=item IO::AIO::mlockall $flags
2382
2383Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2384but is blocking.
2385
2145=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2386=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2146 2387
2147Calls the C<munlock> function, undoing the effects of a previous 2388Calls the C<munlock> function, undoing the effects of a previous
2148C<aio_mlock> call (see its description for details). 2389C<aio_mlock> call (see its description for details).
2149 2390
… …
2198C<$flags> is non-zero, fails with C<ENOSYS>. 2439C<$flags> is non-zero, fails with C<ENOSYS>.
2199 2440
2200Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the 2441Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2201time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and 2442time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2202C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported. 2443C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2444
2445Example: create a pipe race-free w.r.t. threads and fork:
2446
2447 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2448 or die "pipe2: $!\n";
2449
2450=item $fh = IO::AIO::memfd_create $pathname[, $flags]
2451
2452This is a direct interface to the Linux L<memfd_create(2)> system
2453call. The (unhelpful) default for C<$flags> is C<0>, but your default
2454should be C<IO::AIO::MFD_CLOEXEC>.
2455
2456On success, the new memfd filehandle is returned, otherwise returns
2457C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
2458
2459Please refer to L<memfd_create(2)> for more info on this call.
2460
2461The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
2462C<IO::AIO::MFD_ALLOW_SEALING> and C<IO::AIO::MFD_HUGETLB>.
2463
2464Example: create a new memfd.
2465
2466 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2467 or die "m,emfd_create: $!\n";
2468=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2469
2470This is a direct interface to the Linux L<eventfd(2)> system call. The
2471(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2472
2473On success, the new eventfd filehandle is returned, otherwise returns
2474C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2475
2476Please refer to L<eventfd(2)> for more info on this call.
2477
2478The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2479C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2480
2481Example: create a new eventfd filehandle:
2482
2483 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2484 or die "eventfd: $!\n";
2485
2486=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2487
2488This is a direct interface to the Linux L<timerfd_create(2)> system
2489call. The (unhelpful) default for C<$flags> is C<0>, but your default
2490should be C<IO::AIO::TFD_CLOEXEC>.
2491
2492On success, the new timerfd filehandle is returned, otherwise returns
2493C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
2494
2495Please refer to L<timerfd_create(2)> for more info on this call.
2496
2497The following C<$clockid> values are
2498available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2499C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2500C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2501C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2502
2503The following C<$flags> values are available (Linux
25042.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2505
2506Example: create a new timerfd and set it to one-second repeated alarms,
2507then wait for two alarms:
2508
2509 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2510 or die "timerfd_create: $!\n";
2511
2512 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2513 or die "timerfd_settime: $!\n";
2514
2515 for (1..2) {
2516 8 == sysread $fh, my $buf, 8
2517 or die "timerfd read failure\n";
2518
2519 printf "number of expirations (likely 1): %d\n",
2520 unpack "Q", $buf;
2521 }
2522
2523=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2524
2525This is a direct interface to the Linux L<timerfd_settime(2)> system
2526call. Please refer to its manpage for more info on this call.
2527
2528The new itimerspec is specified using two (possibly fractional) second
2529values, C<$new_interval> and C<$new_value>).
2530
2531On success, the current interval and value are returned (as per
2532C<timerfd_gettime>). On failure, the empty list is returned.
2533
2534The following C<$flags> values are
2535available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2536C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2537
2538See C<IO::AIO::timerfd_create> for a full example.
2539
2540=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2541
2542This is a direct interface to the Linux L<timerfd_gettime(2)> system
2543call. Please refer to its manpage for more info on this call.
2544
2545On success, returns the current values of interval and value for the given
2546timerfd (as potentially fractional second values). On failure, the empty
2547list is returned.
2203 2548
2204=back 2549=back
2205 2550
2206=cut 2551=cut
2207 2552
… …
2273the process will result in undefined behaviour. Calling it at any time 2618the process will result in undefined behaviour. Calling it at any time
2274will also result in any undefined (by POSIX) behaviour. 2619will also result in any undefined (by POSIX) behaviour.
2275 2620
2276=back 2621=back
2277 2622
2623=head2 LINUX-SPECIFIC CALLS
2624
2625When a call is documented as "linux-specific" then this means it
2626originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2627availability and compatibility of such calls regardless of the platform
2628it is compiled on, so platforms such as FreeBSD which often implement
2629these calls will work. When in doubt, call them and see if they fail wth
2630C<ENOSYS>.
2631
2278=head2 MEMORY USAGE 2632=head2 MEMORY USAGE
2279 2633
2280Per-request usage: 2634Per-request usage:
2281 2635
2282Each aio request uses - depending on your architecture - around 100-200 2636Each aio request uses - depending on your architecture - around 100-200
… …
2294temporary buffers, and each thread requires a stack and other data 2648temporary buffers, and each thread requires a stack and other data
2295structures (usually around 16k-128k, depending on the OS). 2649structures (usually around 16k-128k, depending on the OS).
2296 2650
2297=head1 KNOWN BUGS 2651=head1 KNOWN BUGS
2298 2652
2299Known bugs will be fixed in the next release. 2653Known bugs will be fixed in the next release :)
2654
2655=head1 KNOWN ISSUES
2656
2657Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2658or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2659non-created hash slots or other scalars I didn't think of. It's best to
2660avoid such and either use scalar variables or making sure that the scalar
2661exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2662
2663I am not sure anything can be done about this, so this is considered a
2664known issue, rather than a bug.
2300 2665
2301=head1 SEE ALSO 2666=head1 SEE ALSO
2302 2667
2303L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2668L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2304more natural syntax. 2669more natural syntax.

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