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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.258 by root, Thu Jan 21 23:04:46 2016 UTC vs.
Revision 1.300 by root, Sun Mar 10 12:11:46 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 = 4.33; 176 our $VERSION = 4.71;
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)
534 545
535Works like perl's C<stat> or C<lstat> in void context. The callback will 546Works almost exactly like perl's C<stat> or C<lstat> in void context. The
536be called after the stat and the results will be available using C<stat _> 547callback will be called after the stat and the results will be available
537or C<-s _> etc... 548using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
549and C<-T>).
538 550
539The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 551The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
540for an explanation. 552for an explanation.
541 553
542Currently, the stats are always 64-bit-stats, i.e. instead of returning an 554Currently, the stats are always 64-bit-stats, i.e. instead of returning an
… …
549behaviour). 561behaviour).
550 562
551C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 563C<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>, 564C<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>. 565C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
566
567To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
568ACCESS>.
554 569
555Example: Print the length of F</etc/passwd>: 570Example: Print the length of F</etc/passwd>:
556 571
557 aio_stat "/etc/passwd", sub { 572 aio_stat "/etc/passwd", sub {
558 $_[0] and die "stat failed: $!"; 573 $_[0] and die "stat failed: $!";
… …
602 namemax => 255, 617 namemax => 255,
603 frsize => 1024, 618 frsize => 1024,
604 fsid => 1810 619 fsid => 1810
605 } 620 }
606 621
607Here is a (likely partial - send me updates!) list of fsid values used by
608Linux - it is safe to hardcode these when C<$^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) 622=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
693 623
694Works like perl's C<utime> function (including the special case of $atime 624Works like perl's C<utime> function (including the special case of $atime
695and $mtime being undef). Fractional times are supported if the underlying 625and $mtime being undef). Fractional times are supported if the underlying
696syscalls support them. 626syscalls support them.
697 627
698When called with a pathname, uses utimes(2) if available, otherwise 628When called with a pathname, uses utimensat(2) or utimes(2) if available,
699utime(2). If called on a file descriptor, uses futimes(2) if available, 629otherwise utime(2). If called on a file descriptor, uses futimens(2)
700otherwise returns ENOSYS, so this is not portable. 630or futimes(2) if available, otherwise returns ENOSYS, so this is not
631portable.
701 632
702Examples: 633Examples:
703 634
704 # set atime and mtime to current time (basically touch(1)): 635 # set atime and mtime to current time (basically touch(1)):
705 aio_utime "path", undef, undef; 636 aio_utime "path", undef, undef;
… …
733C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate 664C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
734space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>, 665space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
735to deallocate a file range. 666to deallocate a file range.
736 667
737IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range 668IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
738(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see 669(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
739your L<fallocate(2)> manpage). 670C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
671to unshare shared blocks (see your L<fallocate(2)> manpage).
740 672
741The file system block size used by C<fallocate> is presumably the 673The file system block size used by C<fallocate> is presumably the
742C<f_bsize> returned by C<statvfs>. 674C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
675can dictate other limitations.
743 676
744If C<fallocate> isn't available or cannot be emulated (currently no 677If C<fallocate> isn't available or cannot be emulated (currently no
745emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 678emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
746 679
747 680
… …
806On systems that support the AIO::WD working directory abstraction 739On systems that support the AIO::WD working directory abstraction
807natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 740natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
808of failing, C<rename> is called on the absolute path of C<$wd>. 741of failing, C<rename> is called on the absolute path of C<$wd>.
809 742
810 743
744=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
745
746Basically a version of C<aio_rename> with an additional C<$flags>
747argument. Calling this with C<$flags=0> is the same as calling
748C<aio_rename>.
749
750Non-zero flags are currently only supported on GNU/Linux systems that
751support renameat2. Other systems fail with C<ENOSYS> in this case.
752
753The following constants are available (missing ones are, as usual C<0>),
754see renameat2(2) for details:
755
756C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
757and C<IO::AIO::RENAME_WHITEOUT>.
758
759
811=item aio_mkdir $pathname, $mode, $callback->($status) 760=item aio_mkdir $pathname, $mode, $callback->($status)
812 761
813Asynchronously mkdir (create) a directory and call the callback with 762Asynchronously mkdir (create) a directory and call the callback with
814the result code. C<$mode> will be modified by the umask at the time the 763the result code. C<$mode> will be modified by the umask at the time the
815request is executed, so do not change your umask. 764request is executed, so do not change your umask.
… …
846 795
847=over 4 796=over 4
848 797
849=item IO::AIO::READDIR_DENTS 798=item IO::AIO::READDIR_DENTS
850 799
851When this flag is off, then the callback gets an arrayref consisting of 800Normally the callback gets an arrayref consisting of names only (as
852names only (as with C<aio_readdir>), otherwise it gets an arrayref with 801with C<aio_readdir>). If this flag is set, then the callback gets an
853C<[$name, $type, $inode]> arrayrefs, each describing a single directory 802arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
854entry in more detail. 803single directory entry in more detail:
855 804
856C<$name> is the name of the entry. 805C<$name> is the name of the entry.
857 806
858C<$type> is one of the C<IO::AIO::DT_xxx> constants: 807C<$type> is one of the C<IO::AIO::DT_xxx> constants:
859 808
860C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 809C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
861C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 810C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
862C<IO::AIO::DT_WHT>. 811C<IO::AIO::DT_WHT>.
863 812
864C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 813C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
865know, you have to run stat yourself. Also, for speed reasons, the C<$type> 814to know, you have to run stat yourself. Also, for speed/memory reasons,
866scalars are read-only: you can not modify them. 815the C<$type> scalars are read-only: you must not modify them.
867 816
868C<$inode> is the inode number (which might not be exact on systems with 64 817C<$inode> is the inode number (which might not be exact on systems with 64
869bit inode numbers and 32 bit perls). This field has unspecified content on 818bit inode numbers and 32 bit perls). This field has unspecified content on
870systems that do not deliver the inode information. 819systems that do not deliver the inode information.
871 820
… …
882short names are tried first. 831short names are tried first.
883 832
884=item IO::AIO::READDIR_STAT_ORDER 833=item IO::AIO::READDIR_STAT_ORDER
885 834
886When this flag is set, then the names will be returned in an order 835When this flag is set, then the names will be returned in an order
887suitable for stat()'ing each one. That is, when you plan to stat() 836suitable for stat()'ing each one. That is, when you plan to stat() most or
888all files in the given directory, then the returned order will likely 837all files in the given directory, then the returned order will likely be
889be fastest. 838faster.
890 839
891If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 840If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
892the likely dirs come first, resulting in a less optimal stat order. 841then the likely dirs come first, resulting in a less optimal stat order
842for stat'ing all entries, but likely a more optimal order for finding
843subdirectories.
893 844
894=item IO::AIO::READDIR_FOUND_UNKNOWN 845=item IO::AIO::READDIR_FOUND_UNKNOWN
895 846
896This flag should not be set when calling C<aio_readdirx>. Instead, it 847This flag should not be set when calling C<aio_readdirx>. Instead, it
897is being set by C<aio_readdirx>, when any of the C<$type>'s found were 848is 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. 850C<$type>'s are known, which can be used to speed up some algorithms.
900 851
901=back 852=back
902 853
903 854
855=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
856
857Opens, reads and closes the given file. The data is put into C<$data>,
858which is resized as required.
859
860If C<$offset> is negative, then it is counted from the end of the file.
861
862If C<$length> is zero, then the remaining length of the file is
863used. Also, in this case, the same limitations to modifying C<$data> apply
864as when IO::AIO::mmap is used, i.e. it must only be modified in-place
865with C<substr>. If the size of the file is known, specifying a non-zero
866C<$length> results in a performance advantage.
867
868This request is similar to the older C<aio_load> request, but since it is
869a single request, it might be more efficient to use.
870
871Example: load F</etc/passwd> into C<$passwd>.
872
873 my $passwd;
874 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
875 $_[0] >= 0
876 or die "/etc/passwd: $!\n";
877
878 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
879 print $passwd;
880 };
881 IO::AIO::flush;
882
883
904=item aio_load $pathname, $data, $callback->($status) 884=item aio_load $pathname, $data, $callback->($status)
905 885
906This is a composite request that tries to fully load the given file into 886This is a composite request that tries to fully load the given file into
907memory. Status is the same as with aio_read. 887memory. Status is the same as with aio_read.
888
889Using C<aio_slurp> might be more efficient, as it is a single request.
908 890
909=cut 891=cut
910 892
911sub aio_load($$;$) { 893sub aio_load($$;$) {
912 my ($path, undef, $cb) = @_; 894 my ($path, undef, $cb) = @_;
… …
932=item aio_copy $srcpath, $dstpath, $callback->($status) 914=item aio_copy $srcpath, $dstpath, $callback->($status)
933 915
934Try to copy the I<file> (directories not supported as either source or 916Try to copy the I<file> (directories not supported as either source or
935destination) from C<$srcpath> to C<$dstpath> and call the callback with 917destination) from C<$srcpath> to C<$dstpath> and call the callback with
936a status of C<0> (ok) or C<-1> (error, see C<$!>). 918a status of C<0> (ok) or C<-1> (error, see C<$!>).
919
920Existing destination files will be truncated.
937 921
938This is a composite request that creates the destination file with 922This is a composite request that creates the destination file with
939mode 0200 and copies the contents of the source file into it using 923mode 0200 and copies the contents of the source file into it using
940C<aio_sendfile>, followed by restoring atime, mtime, access mode and 924C<aio_sendfile>, followed by restoring atime, mtime, access mode and
941uid/gid, in that order. 925uid/gid, in that order.
… …
1051Scans a directory (similar to C<aio_readdir>) but additionally tries to 1035Scans a directory (similar to C<aio_readdir>) but additionally tries to
1052efficiently separate the entries of directory C<$path> into two sets of 1036efficiently separate the entries of directory C<$path> into two sets of
1053names, directories you can recurse into (directories), and ones you cannot 1037names, directories you can recurse into (directories), and ones you cannot
1054recurse into (everything else, including symlinks to directories). 1038recurse into (everything else, including symlinks to directories).
1055 1039
1056C<aio_scandir> is a composite request that creates of many sub requests_ 1040C<aio_scandir> is a composite request that generates many sub requests.
1057C<$maxreq> specifies the maximum number of outstanding aio requests that 1041C<$maxreq> specifies the maximum number of outstanding aio requests that
1058this function generates. If it is C<< <= 0 >>, then a suitable default 1042this function generates. If it is C<< <= 0 >>, then a suitable default
1059will be chosen (currently 4). 1043will be chosen (currently 4).
1060 1044
1061On error, the callback is called without arguments, otherwise it receives 1045On error, the callback is called without arguments, otherwise it receives
… …
1125 aioreq_pri $pri; 1109 aioreq_pri $pri;
1126 add $grp aio_stat $wd, sub { 1110 add $grp aio_stat $wd, sub {
1127 return $grp->result () if $_[0]; 1111 return $grp->result () if $_[0];
1128 my $now = time; 1112 my $now = time;
1129 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1113 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1114 my $rdxflags = READDIR_DIRS_FIRST;
1115
1116 if ((stat _)[3] < 2) {
1117 # at least one non-POSIX filesystem exists
1118 # that returns useful DT_type values: btrfs,
1119 # so optimise for this here by requesting dents
1120 $rdxflags |= READDIR_DENTS;
1121 }
1130 1122
1131 # read the directory entries 1123 # read the directory entries
1132 aioreq_pri $pri; 1124 aioreq_pri $pri;
1133 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1125 add $grp aio_readdirx $wd, $rdxflags, sub {
1134 my $entries = shift 1126 my ($entries, $flags) = @_
1135 or return $grp->result (); 1127 or return $grp->result ();
1128
1129 if ($rdxflags & READDIR_DENTS) {
1130 # if we requested type values, see if we can use them directly.
1131
1132 # if there were any DT_UNKNOWN entries then we assume we
1133 # don't know. alternatively, we could assume that if we get
1134 # one DT_DIR, then all directories are indeed marked with
1135 # DT_DIR, but this seems not required for btrfs, and this
1136 # is basically the "btrfs can't get it's act together" code
1137 # branch.
1138 unless ($flags & READDIR_FOUND_UNKNOWN) {
1139 # now we have valid DT_ information for all entries,
1140 # so use it as an optimisation without further stat's.
1141 # they must also all be at the beginning of @$entries
1142 # by now.
1143
1144 my $dirs;
1145
1146 if (@$entries) {
1147 for (0 .. $#$entries) {
1148 if ($entries->[$_][1] != DT_DIR) {
1149 # splice out directories
1150 $dirs = [splice @$entries, 0, $_];
1151 last;
1152 }
1153 }
1154
1155 # if we didn't find any non-dir, then all entries are dirs
1156 unless ($dirs) {
1157 ($dirs, $entries) = ($entries, []);
1158 }
1159 } else {
1160 # directory is empty, so there are no sbdirs
1161 $dirs = [];
1162 }
1163
1164 # either splice'd the directories out or the dir was empty.
1165 # convert dents to filenames
1166 $_ = $_->[0] for @$dirs;
1167 $_ = $_->[0] for @$entries;
1168
1169 return $grp->result ($dirs, $entries);
1170 }
1171
1172 # cannot use, so return to our old ways
1173 # by pretending we only scanned for names.
1174 $_ = $_->[0] for @$entries;
1175 }
1136 1176
1137 # stat the dir another time 1177 # stat the dir another time
1138 aioreq_pri $pri; 1178 aioreq_pri $pri;
1139 add $grp aio_stat $wd, sub { 1179 add $grp aio_stat $wd, sub {
1140 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1180 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1227 }; 1267 };
1228 1268
1229 $grp 1269 $grp
1230} 1270}
1231 1271
1272=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1273
1274=item aio_ioctl $fh, $request, $buf, $callback->($status)
1275
1276These work just like the C<fcntl> and C<ioctl> built-in functions, except
1277they execute asynchronously and pass the return value to the callback.
1278
1279Both calls can be used for a lot of things, some of which make more sense
1280to run asynchronously in their own thread, while some others make less
1281sense. For example, calls that block waiting for external events, such
1282as locking, will also lock down an I/O thread while it is waiting, which
1283can deadlock the whole I/O system. At the same time, there might be no
1284alternative to using a thread to wait.
1285
1286So in general, you should only use these calls for things that do
1287(filesystem) I/O, not for things that wait for other events (network,
1288other processes), although if you are careful and know what you are doing,
1289you still can.
1290
1291The following constants are available (missing ones are, as usual C<0>):
1292
1293C<F_DUPFD_CLOEXEC>,
1294
1295C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1296
1297C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1298
1299C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1300C<FS_IOC_FIEMAP>.
1301
1302C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1303C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1304
1305C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1306C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1307C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1308C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1309C<FS_FL_USER_MODIFIABLE>.
1310
1311C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1312C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1313C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1314C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1315
1232=item aio_sync $callback->($status) 1316=item aio_sync $callback->($status)
1233 1317
1234Asynchronously call sync and call the callback when finished. 1318Asynchronously call sync and call the callback when finished.
1235 1319
1236=item aio_fsync $fh, $callback->($status) 1320=item aio_fsync $fh, $callback->($status)
… …
1304 }; 1388 };
1305 1389
1306 $grp 1390 $grp
1307} 1391}
1308 1392
1309=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1393=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1310 1394
1311This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1395This 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 1396scalars (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 1397scalars 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 1398scalar must only be modified in-place while an aio operation is pending on
… …
1316 1400
1317It calls the C<msync> function of your OS, if available, with the memory 1401It 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 1402area 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> 1403later. 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 1404is 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 1405either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1322C<IO::AIO::MS_SYNC>. 1406C<IO::AIO::MS_INVALIDATE>.
1323 1407
1324=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1408=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1325 1409
1326This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1410This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1327scalars. 1411scalars.
… …
1357 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1441 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1358 aio_mlock $data; # mlock in background 1442 aio_mlock $data; # mlock in background
1359 1443
1360=item aio_mlockall $flags, $callback->($status) 1444=item aio_mlockall $flags, $callback->($status)
1361 1445
1362Calls the C<mlockall> function with the given C<$flags> (a combination of 1446Calls the C<mlockall> function with the given C<$flags> (a
1363C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1447combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1448C<IO::AIO::MCL_ONFAULT>).
1364 1449
1365On systems that do not implement C<mlockall>, this function returns C<-1> 1450On systems that do not implement C<mlockall>, this function returns C<-1>
1366and sets errno to C<ENOSYS>. 1451and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1452by the system result in a return value of C<-1> with errno being set to
1453C<EINVAL>.
1367 1454
1368Note that the corresponding C<munlockall> is synchronous and is 1455Note that the corresponding C<munlockall> is synchronous and is
1369documented under L<MISCELLANEOUS FUNCTIONS>. 1456documented under L<MISCELLANEOUS FUNCTIONS>.
1370 1457
1371Example: asynchronously lock all current and future pages into memory. 1458Example: asynchronously lock all current and future pages into memory.
… …
1410C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1497C<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>, 1498C<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 1499C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1413C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1500C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1414 1501
1415At the time of this writing (Linux 3.2), this requets is unreliable unless 1502At the time of this writing (Linux 3.2), this request is unreliable unless
1416C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1503C<$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 1504it to return all extents of a range for files with a large number of
1418extents. The code works around all these issues if C<$count> is undef. 1505extents. The code (only) works around all these issues if C<$count> is
1506C<undef>.
1419 1507
1420=item aio_group $callback->(...) 1508=item aio_group $callback->(...)
1421 1509
1422This is a very special aio request: Instead of doing something, it is a 1510This 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 1511container for other aio requests, which is useful if you want to bundle
… …
1536There are some caveats: when directories get renamed (or deleted), the 1624There are some caveats: when directories get renamed (or deleted), the
1537pathname string doesn't change, so will point to the new directory (or 1625pathname string doesn't change, so will point to the new directory (or
1538nowhere at all), while the directory fd, if available on the system, 1626nowhere at all), while the directory fd, if available on the system,
1539will still point to the original directory. Most functions accepting a 1627will still point to the original directory. Most functions accepting a
1540pathname will use the directory fd on newer systems, and the string on 1628pathname will use the directory fd on newer systems, and the string on
1541older systems. Some functions (such as realpath) will always rely on the 1629older systems. Some functions (such as C<aio_realpath>) will always rely on
1542string form of the pathname. 1630the string form of the pathname.
1543 1631
1544So this functionality is mainly useful to get some protection against 1632So 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 1633C<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 1634reference, and to speed up doing many operations in the same directory
1547(e.g. when stat'ing all files in a directory). 1635(e.g. when stat'ing all files in a directory).
… …
1755The default value for the limit is C<0>, but note that setting a feeder 1843The default value for the limit is C<0>, but note that setting a feeder
1756automatically bumps it up to C<2>. 1844automatically bumps it up to C<2>.
1757 1845
1758=back 1846=back
1759 1847
1848
1760=head2 SUPPORT FUNCTIONS 1849=head2 SUPPORT FUNCTIONS
1761 1850
1762=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1851=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1763 1852
1764=over 4 1853=over 4
… …
1829Strictly equivalent to: 1918Strictly equivalent to:
1830 1919
1831 IO::AIO::poll_wait, IO::AIO::poll_cb 1920 IO::AIO::poll_wait, IO::AIO::poll_cb
1832 while IO::AIO::nreqs; 1921 while IO::AIO::nreqs;
1833 1922
1923This function can be useful at program aborts, to make sure outstanding
1924I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1925this function on normal exits), or when you are merely using C<IO::AIO>
1926for its more advanced functions, rather than for async I/O, e.g.:
1927
1928 my ($dirs, $nondirs);
1929 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1930 IO::AIO::flush;
1931 # $dirs, $nondirs are now set
1932
1834=item IO::AIO::max_poll_reqs $nreqs 1933=item IO::AIO::max_poll_reqs $nreqs
1835 1934
1836=item IO::AIO::max_poll_time $seconds 1935=item IO::AIO::max_poll_time $seconds
1837 1936
1838These set the maximum number of requests (default C<0>, meaning infinity) 1937These set the maximum number of requests (default C<0>, meaning infinity)
… …
1864 poll => 'r', nice => 1, 1963 poll => 'r', nice => 1,
1865 cb => &IO::AIO::poll_cb); 1964 cb => &IO::AIO::poll_cb);
1866 1965
1867=back 1966=back
1868 1967
1968
1869=head3 CONTROLLING THE NUMBER OF THREADS 1969=head3 CONTROLLING THE NUMBER OF THREADS
1870 1970
1871=over 1971=over
1872 1972
1873=item IO::AIO::min_parallel $nthreads 1973=item IO::AIO::min_parallel $nthreads
… …
1939This is a very bad function to use in interactive programs because it 2039This 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 2040blocks, and a bad way to reduce concurrency because it is inexact: Better
1941use an C<aio_group> together with a feed callback. 2041use an C<aio_group> together with a feed callback.
1942 2042
1943Its main use is in scripts without an event loop - when you want to stat 2043Its main use is in scripts without an event loop - when you want to stat
1944a lot of files, you can write somehting like this: 2044a lot of files, you can write something like this:
1945 2045
1946 IO::AIO::max_outstanding 32; 2046 IO::AIO::max_outstanding 32;
1947 2047
1948 for my $path (...) { 2048 for my $path (...) {
1949 aio_stat $path , ...; 2049 aio_stat $path , ...;
… …
1960The default value for C<max_outstanding> is very large, so there is no 2060The default value for C<max_outstanding> is very large, so there is no
1961practical limit on the number of outstanding requests. 2061practical limit on the number of outstanding requests.
1962 2062
1963=back 2063=back
1964 2064
2065
1965=head3 STATISTICAL INFORMATION 2066=head3 STATISTICAL INFORMATION
1966 2067
1967=over 2068=over
1968 2069
1969=item IO::AIO::nreqs 2070=item IO::AIO::nreqs
… …
1985 2086
1986Returns the number of requests currently in the pending state (executed, 2087Returns the number of requests currently in the pending state (executed,
1987but not yet processed by poll_cb). 2088but not yet processed by poll_cb).
1988 2089
1989=back 2090=back
2091
2092
2093=head3 SUBSECOND STAT TIME ACCESS
2094
2095Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2096generally find access/modification and change times with subsecond time
2097accuracy of the system supports it, but perl's built-in functions only
2098return the integer part.
2099
2100The following functions return the timestamps of the most recent
2101stat with subsecond precision on most systems and work both after
2102C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2103value is only meaningful after a successful C<stat>/C<lstat> call, or
2104during/after a successful C<aio_stat>/C<aio_lstat> callback.
2105
2106This is similar to the L<Time::HiRes> C<stat> functions, but can return
2107full resolution without rounding and work with standard perl C<stat>,
2108alleviating the need to call the special C<Time::HiRes> functions, which
2109do not act like their perl counterparts.
2110
2111On operating systems or file systems where subsecond time resolution is
2112not supported or could not be detected, a fractional part of C<0> is
2113returned, so it is always safe to call these functions.
2114
2115=over 4
2116
2117=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2118
2119Return the access, modication, change or birth time, respectively,
2120including fractional part. Due to the limited precision of floating point,
2121the accuracy on most platforms is only a bit better than milliseconds
2122for times around now - see the I<nsec> function family, below, for full
2123accuracy.
2124
2125File birth time is only available when the OS and perl support it (on
2126FreeBSD and NetBSD at the time of this writing, although support is
2127adaptive, so if your OS/perl gains support, IO::AIO can take avdantage of
2128it). On systems where it isn't available, C<0> is currently returned, but
2129this might change to C<undef> in a future version.
2130
2131=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2132
2133Returns access, modification, change and birth time all in one go, and
2134maybe more times in the future version.
2135
2136=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2137
2138Return the fractional access, modifcation, change or birth time, in nanoseconds,
2139as an integer in the range C<0> to C<999999999>.
2140
2141Note that no accessors are provided for access, modification and
2142change times - you need to get those from C<stat _> if required (C<int
2143IO::AIO::st_atime> and so on will I<not> generally give you the correct
2144value).
2145
2146=item $seconds = IO::AIO::st_btimesec
2147
2148The (integral) seconds part of the file birth time, if available.
2149
2150=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2151
2152Like the functions above, but returns all four times in one go (and maybe
2153more in future versions).
2154
2155=item $counter = IO::AIO::st_gen
2156
2157Returns the generation counter (in practice this is just a random number)
2158of the file. This is only available on platforms which have this member in
2159their C<struct stat> (most BSDs at the time of this writing) and generally
2160only to the root usert. If unsupported, C<0> is returned, but this might
2161change to C<undef> in a future version.
2162
2163=back
2164
2165Example: print the high resolution modification time of F</etc>, using
2166C<stat>, and C<IO::AIO::aio_stat>.
2167
2168 if (stat "/etc") {
2169 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2170 }
2171
2172 IO::AIO::aio_stat "/etc", sub {
2173 $_[0]
2174 and return;
2175
2176 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2177 };
2178
2179 IO::AIO::flush;
2180
2181Output of the awbove on my system, showing reduced and full accuracy:
2182
2183 stat(/etc) mtime: 1534043702.020808
2184 aio_stat(/etc) mtime: 1534043702.020807792
2185
1990 2186
1991=head3 MISCELLANEOUS FUNCTIONS 2187=head3 MISCELLANEOUS FUNCTIONS
1992 2188
1993IO::AIO implements some functions that are useful when you want to use 2189IO::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 2190some "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_*> 2191"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
1996counterpart. 2192counterpart.
1997 2193
1998=over 4 2194=over 4
2195
2196=item $numfd = IO::AIO::get_fdlimit
2197
2198This function is I<EXPERIMENTAL> and subject to change.
2199
2200Tries to find the current file descriptor limit and returns it, or
2201C<undef> and sets C<$!> in case of an error. The limit is one larger than
2202the highest valid file descriptor number.
2203
2204=item IO::AIO::min_fdlimit [$numfd]
2205
2206This function is I<EXPERIMENTAL> and subject to change.
2207
2208Try to increase the current file descriptor limit(s) to at least C<$numfd>
2209by changing the soft or hard file descriptor resource limit. If C<$numfd>
2210is missing, it will try to set a very high limit, although this is not
2211recommended when you know the actual minimum that you require.
2212
2213If the limit cannot be raised enough, the function makes a best-effort
2214attempt to increase the limit as much as possible, using various
2215tricks, while still failing. You can query the resulting limit using
2216C<IO::AIO::get_fdlimit>.
2217
2218If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2219true.
1999 2220
2000=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2221=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
2001 2222
2002Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2223Calls 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 2224but is blocking (this makes most sense if you know the input data is
… …
2020=item IO::AIO::madvise $scalar, $offset, $len, $advice 2241=item IO::AIO::madvise $scalar, $offset, $len, $advice
2021 2242
2022Simply calls the C<posix_madvise> function (see its 2243Simply calls the C<posix_madvise> function (see its
2023manpage for details). The following advice constants are 2244manpage for details). The following advice constants are
2024available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2245available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2025C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2246C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2247C<IO::AIO::MADV_DONTNEED>.
2248
2249If C<$offset> is negative, counts from the end. If C<$length> is negative,
2250the remaining length of the C<$scalar> is used. If possible, C<$length>
2251will be reduced to fit into the C<$scalar>.
2026 2252
2027On systems that do not implement C<posix_madvise>, this function returns 2253On systems that do not implement C<posix_madvise>, this function returns
2028ENOSYS, otherwise the return value of C<posix_madvise>. 2254ENOSYS, otherwise the return value of C<posix_madvise>.
2029 2255
2030=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2256=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2032Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2258Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2033$scalar (see its manpage for details). The following protect 2259$scalar (see its manpage for details). The following protect
2034constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2260constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2035C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2261C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2036 2262
2263If C<$offset> is negative, counts from the end. If C<$length> is negative,
2264the remaining length of the C<$scalar> is used. If possible, C<$length>
2265will be reduced to fit into the C<$scalar>.
2266
2037On systems that do not implement C<mprotect>, this function returns 2267On systems that do not implement C<mprotect>, this function returns
2038ENOSYS, otherwise the return value of C<mprotect>. 2268ENOSYS, otherwise the return value of C<mprotect>.
2039 2269
2040=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2270=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2041 2271
2042Memory-maps a file (or anonymous memory range) and attaches it to the 2272Memory-maps a file (or anonymous memory range) and attaches it to the
2043given C<$scalar>, which will act like a string scalar. Returns true on 2273given C<$scalar>, which will act like a string scalar. Returns true on
2044success, and false otherwise. 2274success, and false otherwise.
2045 2275
2276The scalar must exist, but its contents do not matter - this means you
2277cannot use a nonexistant array or hash element. When in doubt, C<undef>
2278the scalar first.
2279
2046The only operations allowed on the scalar are C<substr>/C<vec> that don't 2280The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2047change the string length, and most read-only operations such as copying it 2281which don't change the string length, and most read-only operations such
2048or searching it with regexes and so on. 2282as copying it or searching it with regexes and so on.
2049 2283
2050Anything else is unsafe and will, at best, result in memory leaks. 2284Anything else is unsafe and will, at best, result in memory leaks.
2051 2285
2052The memory map associated with the C<$scalar> is automatically removed 2286The memory map associated with the C<$scalar> is automatically removed
2053when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2287when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2054C<IO::AIO::munmap> functions are called. 2288or C<IO::AIO::munmap> functions are called on it.
2055 2289
2056This calls the C<mmap>(2) function internally. See your system's manual 2290This calls the C<mmap>(2) function internally. See your system's manual
2057page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2291page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2058 2292
2059The C<$length> must be larger than zero and smaller than the actual 2293The C<$length> must be larger than zero and smaller than the actual
… …
2097 2331
2098=item IO::AIO::munmap $scalar 2332=item IO::AIO::munmap $scalar
2099 2333
2100Removes a previous mmap and undefines the C<$scalar>. 2334Removes a previous mmap and undefines the C<$scalar>.
2101 2335
2336=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2337
2338Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2339been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2340C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2341
2342Returns true if successful, and false otherwise. If the underlying mmapped
2343region has changed address, then the true value has the numerical value
2344C<1>, otherwise it has the numerical value C<0>:
2345
2346 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2347 or die "mremap: $!";
2348
2349 if ($success*1) {
2350 warn "scalar has chanegd address in memory\n";
2351 }
2352
2353C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2354implemented, but not supported and might go away in a future version.
2355
2356On systems where this call is not supported or is not emulated, this call
2357returns falls and sets C<$!> to C<ENOSYS>.
2358
2359=item IO::AIO::mlockall $flags
2360
2361Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2362but is blocking.
2363
2102=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2364=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2103 2365
2104Calls the C<munlock> function, undoing the effects of a previous 2366Calls the C<munlock> function, undoing the effects of a previous
2105C<aio_mlock> call (see its description for details). 2367C<aio_mlock> call (see its description for details).
2106 2368
… …
2155C<$flags> is non-zero, fails with C<ENOSYS>. 2417C<$flags> is non-zero, fails with C<ENOSYS>.
2156 2418
2157Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the 2419Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2158time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and 2420time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2159C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported. 2421C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2422
2423Example: create a pipe race-free w.r.t. threads and fork:
2424
2425 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2426 or die "pipe2: $!\n";
2427
2428=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2429
2430This is a direct interface to the Linux L<eventfd(2)> system call. The
2431(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2432
2433On success, the new eventfd filehandle is returned, otherwise returns
2434C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2435
2436Please refer to L<eventfd(2)> for more info on this call.
2437
2438The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2439C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2440
2441Example: create a new eventfd filehandle:
2442
2443 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2444 or die "eventfd: $!\n";
2445
2446=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2447
2448This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2449(unhelpful) default for C<$flags> is C<0>.
2450
2451On success, the new timerfd filehandle is returned, otherwise returns
2452C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2453
2454Please refer to L<timerfd_create(2)> for more info on this call.
2455
2456The following C<$clockid> values are
2457available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2458C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2459C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2460C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2461
2462The following C<$flags> values are available (Linux
24632.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2464
2465Example: create a new timerfd and set it to one-second repeated alarms,
2466then wait for two alarms:
2467
2468 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2469 or die "timerfd_create: $!\n";
2470
2471 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2472 or die "timerfd_settime: $!\n";
2473
2474 for (1..2) {
2475 8 == sysread $fh, my $buf, 8
2476 or die "timerfd read failure\n";
2477
2478 printf "number of expirations (likely 1): %d\n",
2479 unpack "Q", $buf;
2480 }
2481
2482=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2483
2484This is a direct interface to the Linux L<timerfd_settime(2)> system
2485call. Please refer to its manpage for more info on this call.
2486
2487The new itimerspec is specified using two (possibly fractional) second
2488values, C<$new_interval> and C<$new_value>).
2489
2490On success, the current interval and value are returned (as per
2491C<timerfd_gettime>). On failure, the empty list is returned.
2492
2493The following C<$flags> values are
2494available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2495C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2496
2497See C<IO::AIO::timerfd_create> for a full example.
2498
2499=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2500
2501This is a direct interface to the Linux L<timerfd_gettime(2)> system
2502call. Please refer to its manpage for more info on this call.
2503
2504On success, returns the current values of interval and value for the given
2505timerfd (as potentially fractional second values). On failure, the empty
2506list is returned.
2160 2507
2161=back 2508=back
2162 2509
2163=cut 2510=cut
2164 2511
… …
2230the process will result in undefined behaviour. Calling it at any time 2577the process will result in undefined behaviour. Calling it at any time
2231will also result in any undefined (by POSIX) behaviour. 2578will also result in any undefined (by POSIX) behaviour.
2232 2579
2233=back 2580=back
2234 2581
2582=head2 LINUX-SPECIFIC CALLS
2583
2584When a call is documented as "linux-specific" then this means it
2585originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2586availability and compatibility of such calls regardless of the platform
2587it is compiled on, so platforms such as FreeBSD which often implement
2588these calls will work. When in doubt, call them and see if they fail wth
2589C<ENOSYS>.
2590
2235=head2 MEMORY USAGE 2591=head2 MEMORY USAGE
2236 2592
2237Per-request usage: 2593Per-request usage:
2238 2594
2239Each aio request uses - depending on your architecture - around 100-200 2595Each aio request uses - depending on your architecture - around 100-200
… …
2251temporary buffers, and each thread requires a stack and other data 2607temporary buffers, and each thread requires a stack and other data
2252structures (usually around 16k-128k, depending on the OS). 2608structures (usually around 16k-128k, depending on the OS).
2253 2609
2254=head1 KNOWN BUGS 2610=head1 KNOWN BUGS
2255 2611
2256Known bugs will be fixed in the next release. 2612Known bugs will be fixed in the next release :)
2613
2614=head1 KNOWN ISSUES
2615
2616Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2617or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2618non-created hash slots or other scalars I didn't think of. It's best to
2619avoid such and either use scalar variables or making sure that the scalar
2620exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2621
2622I am not sure anything can be done about this, so this is considered a
2623known issue, rather than a bug.
2257 2624
2258=head1 SEE ALSO 2625=head1 SEE ALSO
2259 2626
2260L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2627L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2261more natural syntax. 2628more natural syntax.

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