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Revision 1.241 by root, Fri Dec 28 07:33:41 2012 UTC vs.
Revision 1.297 by root, Thu Nov 29 19:53:46 2018 UTC

1=head1 NAME 1=head1 NAME
2 2
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous/Advanced Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
… …
58not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
59files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
60aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
61using threads anyway. 61using threads anyway.
62 62
63In addition to asynchronous I/O, this module also exports some rather
64arcane interfaces, such as C<madvise> or linux's C<splice> system call,
65which is why the C<A> in C<AIO> can also mean I<advanced>.
66
63Although the module will work in the presence of other (Perl-) threads, 67Although the module will work in the presence of other (Perl-) threads,
64it is currently not reentrant in any way, so use appropriate locking 68it is currently not reentrant in any way, so use appropriate locking
65yourself, always call C<poll_cb> from within the same thread, or never 69yourself, always call C<poll_cb> from within the same thread, or never
66call C<poll_cb> (or other C<aio_> functions) recursively. 70call C<poll_cb> (or other C<aio_> functions) recursively.
67 71
68=head2 EXAMPLE 72=head2 EXAMPLE
69 73
70This is a simple example that uses the EV module and loads 74This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 75F</etc/passwd> asynchronously:
72 76
73 use Fcntl;
74 use EV; 77 use EV;
75 use IO::AIO; 78 use IO::AIO;
76 79
77 # register the IO::AIO callback with EV 80 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 81 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
… …
95 98
96 # file contents now in $contents 99 # file contents now in $contents
97 print $contents; 100 print $contents;
98 101
99 # exit event loop and program 102 # exit event loop and program
100 EV::unloop; 103 EV::break;
101 }; 104 };
102 }; 105 };
103 106
104 # possibly queue up other requests, or open GUI windows, 107 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 108 # check for sockets etc. etc.
106 109
107 # process events as long as there are some: 110 # process events as long as there are some:
108 EV::loop; 111 EV::run;
109 112
110=head1 REQUEST ANATOMY AND LIFETIME 113=head1 REQUEST ANATOMY AND LIFETIME
111 114
112Every C<aio_*> function creates a request. which is a C data structure not 115Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 116directly visible to Perl.
… …
168use common::sense; 171use common::sense;
169 172
170use base 'Exporter'; 173use base 'Exporter';
171 174
172BEGIN { 175BEGIN {
173 our $VERSION = '4.18'; 176 our $VERSION = 4.6;
174 177
175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close 178 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 179 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead aio_fiemap 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
180 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 184 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 187 aio_statvfs
188 aio_slurp
185 aio_wd); 189 aio_wd);
186 190
187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
190 nreqs nready npending nthreads 194 nreqs nready npending nthreads
191 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
192 sendfile fadvise madvise 196 sendfile fadvise madvise
193 mmap munmap munlock munlockall); 197 mmap munmap mremap munlock munlockall);
194 198
195 push @AIO_REQ, qw(aio_busy); # not exported 199 push @AIO_REQ, qw(aio_busy); # not exported
196 200
197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
198 202
… …
228 aio_unlink $pathname, $callback->($status) 232 aio_unlink $pathname, $callback->($status)
229 aio_mknod $pathname, $mode, $dev, $callback->($status) 233 aio_mknod $pathname, $mode, $dev, $callback->($status)
230 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
231 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
232 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
233 aio_realpath $pathname, $callback->($link) 237 aio_realpath $pathname, $callback->($path)
234 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
235 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
236 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
237 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
238 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
243 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
244 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
245 aio_rmtree $pathname, $callback->($status) 250 aio_rmtree $pathname, $callback->($status)
251 aio_fcntl $fh, $cmd, $arg, $callback->($status)
252 aio_ioctl $fh, $request, $buf, $callback->($status)
246 aio_sync $callback->($status) 253 aio_sync $callback->($status)
247 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
248 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
249 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
250 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
251 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
252 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
253 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
254 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
255 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
256 aio_group $callback->(...) 263 aio_group $callback->(...)
257 aio_nop $callback->() 264 aio_nop $callback->()
… …
271 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
272 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
273 IO::AIO::nreqs 280 IO::AIO::nreqs
274 IO::AIO::nready 281 IO::AIO::nready
275 IO::AIO::npending 282 IO::AIO::npending
283 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
284 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
276 285
277 IO::AIO::sendfile $ofh, $ifh, $offset, $count 286 IO::AIO::sendfile $ofh, $ifh, $offset, $count
278 IO::AIO::fadvise $fh, $offset, $len, $advice 287 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 288 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar 289 IO::AIO::munmap $scalar
290 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
281 IO::AIO::madvise $scalar, $offset, $length, $advice 291 IO::AIO::madvise $scalar, $offset, $length, $advice
282 IO::AIO::mprotect $scalar, $offset, $length, $protect 292 IO::AIO::mprotect $scalar, $offset, $length, $protect
283 IO::AIO::munlock $scalar, $offset = 0, $length = undef 293 IO::AIO::munlock $scalar, $offset = 0, $length = undef
284 IO::AIO::munlockall 294 IO::AIO::munlockall
285 295
… …
395following POSIX and non-POSIX constants are available (missing ones on 405following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 406your system are, as usual, C<0>):
397 407
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 408C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
399C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 409C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
400C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 410C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
401 411
402 412
403=item aio_close $fh, $callback->($status) 413=item aio_close $fh, $callback->($status)
404 414
405Asynchronously close a file and call the callback with the result 415Asynchronously close a file and call the callback with the result
… …
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 450=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 451
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 452=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 453
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 454Reads or writes C<$length> bytes from or to the specified C<$fh> and
445C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 455C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
446and calls the callback without the actual number of bytes read (or -1 on 456calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 457error, just like the syscall).
448 458
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 459C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 460offset plus the actual number of bytes read.
451 461
… …
509As native sendfile syscalls (as practically any non-POSIX interface hacked 519As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 520together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 521on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 522in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 523so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 524fewer bytes than expected might have been transferred.
515 525
516 526
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 527=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 528
519C<aio_readahead> populates the page cache with data from a file so that 529C<aio_readahead> populates the page cache with data from a file so that
… …
523whole pages, so that offset is effectively rounded down to a page boundary 533whole pages, so that offset is effectively rounded down to a page boundary
524and bytes are read up to the next page boundary greater than or equal to 534and bytes are read up to the next page boundary greater than or equal to
525(off-set+length). C<aio_readahead> does not read beyond the end of the 535(off-set+length). C<aio_readahead> does not read beyond the end of the
526file. The current file offset of the file is left unchanged. 536file. The current file offset of the file is left unchanged.
527 537
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 538If that syscall doesn't exist (likely if your kernel isn't Linux) it will
529emulated by simply reading the data, which would have a similar effect. 539be emulated by simply reading the data, which would have a similar effect.
530 540
531 541
532=item aio_stat $fh_or_path, $callback->($status) 542=item aio_stat $fh_or_path, $callback->($status)
533 543
534=item aio_lstat $fh, $callback->($status) 544=item aio_lstat $fh, $callback->($status)
535 545
536Works 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
537be 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
538or C<-s _> etc... 548using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
549and C<-T>).
539 550
540The 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,
541for an explanation. 552for an explanation.
542 553
543Currently, 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
… …
550behaviour). 561behaviour).
551 562
552C<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>,
553C<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>,
554C<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>.
555 569
556Example: Print the length of F</etc/passwd>: 570Example: Print the length of F</etc/passwd>:
557 571
558 aio_stat "/etc/passwd", sub { 572 aio_stat "/etc/passwd", sub {
559 $_[0] and die "stat failed: $!"; 573 $_[0] and die "stat failed: $!";
… …
603 namemax => 255, 617 namemax => 255,
604 frsize => 1024, 618 frsize => 1024,
605 fsid => 1810 619 fsid => 1810
606 } 620 }
607 621
608Here is a (likely partial) list of fsid values used by Linux - it is safe
609to hardcode these when the $^O is C<linux>:
610
611 0x0000adf5 adfs
612 0x0000adff affs
613 0x5346414f afs
614 0x09041934 anon-inode filesystem
615 0x00000187 autofs
616 0x42465331 befs
617 0x1badface bfs
618 0x42494e4d binfmt_misc
619 0x9123683e btrfs
620 0x0027e0eb cgroupfs
621 0xff534d42 cifs
622 0x73757245 coda
623 0x012ff7b7 coh
624 0x28cd3d45 cramfs
625 0x453dcd28 cramfs-wend (wrong endianness)
626 0x64626720 debugfs
627 0x00001373 devfs
628 0x00001cd1 devpts
629 0x0000f15f ecryptfs
630 0x00414a53 efs
631 0x0000137d ext
632 0x0000ef53 ext2/ext3
633 0x0000ef51 ext2
634 0x00004006 fat
635 0x65735546 fuseblk
636 0x65735543 fusectl
637 0x0bad1dea futexfs
638 0x01161970 gfs2
639 0x47504653 gpfs
640 0x00004244 hfs
641 0xf995e849 hpfs
642 0x958458f6 hugetlbfs
643 0x2bad1dea inotifyfs
644 0x00009660 isofs
645 0x000072b6 jffs2
646 0x3153464a jfs
647 0x6b414653 k-afs
648 0x0bd00bd0 lustre
649 0x0000137f minix
650 0x0000138f minix 30 char names
651 0x00002468 minix v2
652 0x00002478 minix v2 30 char names
653 0x00004d5a minix v3
654 0x19800202 mqueue
655 0x00004d44 msdos
656 0x0000564c novell
657 0x00006969 nfs
658 0x6e667364 nfsd
659 0x00003434 nilfs
660 0x5346544e ntfs
661 0x00009fa1 openprom
662 0x7461636F ocfs2
663 0x00009fa0 proc
664 0x6165676c pstorefs
665 0x0000002f qnx4
666 0x858458f6 ramfs
667 0x52654973 reiserfs
668 0x00007275 romfs
669 0x67596969 rpc_pipefs
670 0x73636673 securityfs
671 0xf97cff8c selinux
672 0x0000517b smb
673 0x534f434b sockfs
674 0x73717368 squashfs
675 0x62656572 sysfs
676 0x012ff7b6 sysv2
677 0x012ff7b5 sysv4
678 0x01021994 tmpfs
679 0x15013346 udf
680 0x00011954 ufs
681 0x54190100 ufs byteswapped
682 0x00009fa2 usbdevfs
683 0x01021997 v9fs
684 0xa501fcf5 vxfs
685 0xabba1974 xenfs
686 0x012ff7b4 xenix
687 0x58465342 xfs
688 0x012fd16d xia
689
690=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 622=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
691 623
692Works 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
693and $mtime being undef). Fractional times are supported if the underlying 625and $mtime being undef). Fractional times are supported if the underlying
694syscalls support them. 626syscalls support them.
695 627
696When called with a pathname, uses utimes(2) if available, otherwise 628When called with a pathname, uses utimensat(2) or utimes(2) if available,
697utime(2). If called on a file descriptor, uses futimes(2) if available, 629otherwise utime(2). If called on a file descriptor, uses futimens(2)
698otherwise returns ENOSYS, so this is not portable. 630or futimes(2) if available, otherwise returns ENOSYS, so this is not
631portable.
699 632
700Examples: 633Examples:
701 634
702 # set atime and mtime to current time (basically touch(1)): 635 # set atime and mtime to current time (basically touch(1)):
703 aio_utime "path", undef, undef; 636 aio_utime "path", undef, undef;
… …
723Works like truncate(2) or ftruncate(2). 656Works like truncate(2) or ftruncate(2).
724 657
725 658
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 659=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727 660
728Allocates or freed disk space according to the C<$mode> argument. See the 661Allocates or frees disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details. 662linux C<fallocate> documentation for details.
730 663
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 664C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
732to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | 665space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
733IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range. 666to deallocate a file range.
667
668IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
669(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
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).
734 672
735The file system block size used by C<fallocate> is presumably the 673The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>. 674C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
675can dictate other limitations.
737 676
738If C<fallocate> isn't available or cannot be emulated (currently no 677If C<fallocate> isn't available or cannot be emulated (currently no
739emulation 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>.
740 679
741 680
… …
800On systems that support the AIO::WD working directory abstraction 739On systems that support the AIO::WD working directory abstraction
801natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 740natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
802of 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>.
803 742
804 743
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
805=item aio_mkdir $pathname, $mode, $callback->($status) 760=item aio_mkdir $pathname, $mode, $callback->($status)
806 761
807Asynchronously mkdir (create) a directory and call the callback with 762Asynchronously mkdir (create) a directory and call the callback with
808the 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
809request is executed, so do not change your umask. 764request is executed, so do not change your umask.
… …
840 795
841=over 4 796=over 4
842 797
843=item IO::AIO::READDIR_DENTS 798=item IO::AIO::READDIR_DENTS
844 799
845When this flag is off, then the callback gets an arrayref consisting of 800Normally the callback gets an arrayref consisting of names only (as
846names 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
847C<[$name, $type, $inode]> arrayrefs, each describing a single directory 802arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
848entry in more detail. 803single directory entry in more detail:
849 804
850C<$name> is the name of the entry. 805C<$name> is the name of the entry.
851 806
852C<$type> is one of the C<IO::AIO::DT_xxx> constants: 807C<$type> is one of the C<IO::AIO::DT_xxx> constants:
853 808
854C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 809C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
855C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 810C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
856C<IO::AIO::DT_WHT>. 811C<IO::AIO::DT_WHT>.
857 812
858C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 813C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
859know, you have to run stat yourself. Also, for speed reasons, the C<$type> 814to know, you have to run stat yourself. Also, for speed/memory reasons,
860scalars are read-only: you can not modify them. 815the C<$type> scalars are read-only: you must not modify them.
861 816
862C<$inode> is the inode number (which might not be exact on systems with 64 817C<$inode> is the inode number (which might not be exact on systems with 64
863bit inode numbers and 32 bit perls). This field has unspecified content on 818bit inode numbers and 32 bit perls). This field has unspecified content on
864systems that do not deliver the inode information. 819systems that do not deliver the inode information.
865 820
… …
876short names are tried first. 831short names are tried first.
877 832
878=item IO::AIO::READDIR_STAT_ORDER 833=item IO::AIO::READDIR_STAT_ORDER
879 834
880When this flag is set, then the names will be returned in an order 835When this flag is set, then the names will be returned in an order
881suitable for stat()'ing each one. That is, when you plan to stat() 836suitable for stat()'ing each one. That is, when you plan to stat() most or
882all files in the given directory, then the returned order will likely 837all files in the given directory, then the returned order will likely be
883be fastest. 838faster.
884 839
885If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 840If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
886the likely dirs come first, resulting in a less optimal stat order. 841then the likely dirs come first, resulting in a less optimal stat order
842for stat'ing all entries, but likely a more optimal order for finding
843subdirectories.
887 844
888=item IO::AIO::READDIR_FOUND_UNKNOWN 845=item IO::AIO::READDIR_FOUND_UNKNOWN
889 846
890This flag should not be set when calling C<aio_readdirx>. Instead, it 847This flag should not be set when calling C<aio_readdirx>. Instead, it
891is being set by C<aio_readdirx>, when any of the C<$type>'s found were 848is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
893C<$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.
894 851
895=back 852=back
896 853
897 854
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
898=item aio_load $pathname, $data, $callback->($status) 884=item aio_load $pathname, $data, $callback->($status)
899 885
900This 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
901memory. 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.
902 890
903=cut 891=cut
904 892
905sub aio_load($$;$) { 893sub aio_load($$;$) {
906 my ($path, undef, $cb) = @_; 894 my ($path, undef, $cb) = @_;
… …
926=item aio_copy $srcpath, $dstpath, $callback->($status) 914=item aio_copy $srcpath, $dstpath, $callback->($status)
927 915
928Try 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
929destination) from C<$srcpath> to C<$dstpath> and call the callback with 917destination) from C<$srcpath> to C<$dstpath> and call the callback with
930a 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.
931 921
932This is a composite request that creates the destination file with 922This is a composite request that creates the destination file with
933mode 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
934C<aio_sendfile>, followed by restoring atime, mtime, access mode and 924C<aio_sendfile>, followed by restoring atime, mtime, access mode and
935uid/gid, in that order. 925uid/gid, in that order.
… …
1045Scans a directory (similar to C<aio_readdir>) but additionally tries to 1035Scans a directory (similar to C<aio_readdir>) but additionally tries to
1046efficiently separate the entries of directory C<$path> into two sets of 1036efficiently separate the entries of directory C<$path> into two sets of
1047names, directories you can recurse into (directories), and ones you cannot 1037names, directories you can recurse into (directories), and ones you cannot
1048recurse into (everything else, including symlinks to directories). 1038recurse into (everything else, including symlinks to directories).
1049 1039
1050C<aio_scandir> is a composite request that creates of many sub requests_ 1040C<aio_scandir> is a composite request that generates many sub requests.
1051C<$maxreq> specifies the maximum number of outstanding aio requests that 1041C<$maxreq> specifies the maximum number of outstanding aio requests that
1052this function generates. If it is C<< <= 0 >>, then a suitable default 1042this function generates. If it is C<< <= 0 >>, then a suitable default
1053will be chosen (currently 4). 1043will be chosen (currently 4).
1054 1044
1055On error, the callback is called without arguments, otherwise it receives 1045On error, the callback is called without arguments, otherwise it receives
… …
1221 }; 1211 };
1222 1212
1223 $grp 1213 $grp
1224} 1214}
1225 1215
1216=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1217
1218=item aio_ioctl $fh, $request, $buf, $callback->($status)
1219
1220These work just like the C<fcntl> and C<ioctl> built-in functions, except
1221they execute asynchronously and pass the return value to the callback.
1222
1223Both calls can be used for a lot of things, some of which make more sense
1224to run asynchronously in their own thread, while some others make less
1225sense. For example, calls that block waiting for external events, such
1226as locking, will also lock down an I/O thread while it is waiting, which
1227can deadlock the whole I/O system. At the same time, there might be no
1228alternative to using a thread to wait.
1229
1230So in general, you should only use these calls for things that do
1231(filesystem) I/O, not for things that wait for other events (network,
1232other processes), although if you are careful and know what you are doing,
1233you still can.
1234
1235The following constants are available (missing ones are, as usual C<0>):
1236
1237C<F_DUPFD_CLOEXEC>,
1238
1239C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1240
1241C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1242
1243C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1244C<FS_IOC_FIEMAP>.
1245
1246C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1247C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1248
1249C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1250C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1251C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1252C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1253C<FS_FL_USER_MODIFIABLE>.
1254
1255C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1256C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1257C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1258C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1259
1226=item aio_sync $callback->($status) 1260=item aio_sync $callback->($status)
1227 1261
1228Asynchronously call sync and call the callback when finished. 1262Asynchronously call sync and call the callback when finished.
1229 1263
1230=item aio_fsync $fh, $callback->($status) 1264=item aio_fsync $fh, $callback->($status)
… …
1298 }; 1332 };
1299 1333
1300 $grp 1334 $grp
1301} 1335}
1302 1336
1303=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1337=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1304 1338
1305This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1339This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1306scalars (see the C<IO::AIO::mmap> function, although it also works on data 1340scalars (see the C<IO::AIO::mmap> function, although it also works on data
1307scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1341scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1308scalar must only be modified in-place while an aio operation is pending on 1342scalar must only be modified in-place while an aio operation is pending on
… …
1310 1344
1311It calls the C<msync> function of your OS, if available, with the memory 1345It calls the C<msync> function of your OS, if available, with the memory
1312area starting at C<$offset> in the string and ending C<$length> bytes 1346area starting at C<$offset> in the string and ending C<$length> bytes
1313later. If C<$length> is negative, counts from the end, and if C<$length> 1347later. If C<$length> is negative, counts from the end, and if C<$length>
1314is C<undef>, then it goes till the end of the string. The flags can be 1348is C<undef>, then it goes till the end of the string. The flags can be
1315a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1349either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1316C<IO::AIO::MS_SYNC>. 1350C<IO::AIO::MS_INVALIDATE>.
1317 1351
1318=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1352=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1319 1353
1320This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1354This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1321scalars. 1355scalars.
… …
1351 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1385 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1352 aio_mlock $data; # mlock in background 1386 aio_mlock $data; # mlock in background
1353 1387
1354=item aio_mlockall $flags, $callback->($status) 1388=item aio_mlockall $flags, $callback->($status)
1355 1389
1356Calls the C<mlockall> function with the given C<$flags> (a combination of 1390Calls the C<mlockall> function with the given C<$flags> (a
1357C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1391combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1392C<IO::AIO::MCL_ONFAULT>).
1358 1393
1359On systems that do not implement C<mlockall>, this function returns C<-1> 1394On systems that do not implement C<mlockall>, this function returns C<-1>
1360and sets errno to C<ENOSYS>. 1395and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1396by the system result in a return value of C<-1> with errno being set to
1397C<EINVAL>.
1361 1398
1362Note that the corresponding C<munlockall> is synchronous and is 1399Note that the corresponding C<munlockall> is synchronous and is
1363documented under L<MISCELLANEOUS FUNCTIONS>. 1400documented under L<MISCELLANEOUS FUNCTIONS>.
1364 1401
1365Example: asynchronously lock all current and future pages into memory. 1402Example: asynchronously lock all current and future pages into memory.
… …
1404C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1441C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1405C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1442C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1406C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1443C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1407C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1444C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1408 1445
1409At the time of this writing (Linux 3.2), this requets is unreliable unless 1446At the time of this writing (Linux 3.2), this request is unreliable unless
1410C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1447C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1411it to return all extents of a range for files with large number of 1448it to return all extents of a range for files with a large number of
1412extents. The code works around all these issues if C<$count> is undef. 1449extents. The code (only) works around all these issues if C<$count> is
1450C<undef>.
1413 1451
1414=item aio_group $callback->(...) 1452=item aio_group $callback->(...)
1415 1453
1416This is a very special aio request: Instead of doing something, it is a 1454This is a very special aio request: Instead of doing something, it is a
1417container for other aio requests, which is useful if you want to bundle 1455container for other aio requests, which is useful if you want to bundle
… …
1501 aio_stat [$etcdir, "passwd"], sub { 1539 aio_stat [$etcdir, "passwd"], sub {
1502 # yay 1540 # yay
1503 }; 1541 };
1504 }; 1542 };
1505 1543
1506That C<aio_wd> is a request and not a normal function shows that creating 1544The fact that C<aio_wd> is a request and not a normal function shows that
1507an IO::AIO::WD object is itself a potentially blocking operation, which is 1545creating an IO::AIO::WD object is itself a potentially blocking operation,
1508why it is done asynchronously. 1546which is why it is done asynchronously.
1509 1547
1510To stat the directory obtained with C<aio_wd> above, one could write 1548To stat the directory obtained with C<aio_wd> above, one could write
1511either of the following three request calls: 1549either of the following three request calls:
1512 1550
1513 aio_lstat "/etc" , sub { ... # pathname as normal string 1551 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1530There are some caveats: when directories get renamed (or deleted), the 1568There are some caveats: when directories get renamed (or deleted), the
1531pathname string doesn't change, so will point to the new directory (or 1569pathname string doesn't change, so will point to the new directory (or
1532nowhere at all), while the directory fd, if available on the system, 1570nowhere at all), while the directory fd, if available on the system,
1533will still point to the original directory. Most functions accepting a 1571will still point to the original directory. Most functions accepting a
1534pathname will use the directory fd on newer systems, and the string on 1572pathname will use the directory fd on newer systems, and the string on
1535older systems. Some functions (such as realpath) will always rely on the 1573older systems. Some functions (such as C<aio_realpath>) will always rely on
1536string form of the pathname. 1574the string form of the pathname.
1537 1575
1538So this functionality is mainly useful to get some protection against 1576So this functionality is mainly useful to get some protection against
1539C<chdir>, to easily get an absolute path out of a relative path for future 1577C<chdir>, to easily get an absolute path out of a relative path for future
1540reference, and to speed up doing many operations in the same directory 1578reference, and to speed up doing many operations in the same directory
1541(e.g. when stat'ing all files in a directory). 1579(e.g. when stat'ing all files in a directory).
… …
1556passing C<undef> as working directory component of a pathname fails the 1594passing C<undef> as working directory component of a pathname fails the
1557request with C<ENOENT>, there is often no need for error checking in the 1595request with C<ENOENT>, there is often no need for error checking in the
1558C<aio_wd> callback, as future requests using the value will fail in the 1596C<aio_wd> callback, as future requests using the value will fail in the
1559expected way. 1597expected way.
1560 1598
1561If this call isn't available because your OS lacks it or it couldn't be
1562detected, it will be emulated by calling C<fsync> instead.
1563
1564=item IO::AIO::CWD 1599=item IO::AIO::CWD
1565 1600
1566This is a compiletime constant (object) that represents the process 1601This is a compiletime constant (object) that represents the process
1567current working directory. 1602current working directory.
1568 1603
… …
1752The default value for the limit is C<0>, but note that setting a feeder 1787The default value for the limit is C<0>, but note that setting a feeder
1753automatically bumps it up to C<2>. 1788automatically bumps it up to C<2>.
1754 1789
1755=back 1790=back
1756 1791
1792
1757=head2 SUPPORT FUNCTIONS 1793=head2 SUPPORT FUNCTIONS
1758 1794
1759=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1795=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1760 1796
1761=over 4 1797=over 4
… …
1826Strictly equivalent to: 1862Strictly equivalent to:
1827 1863
1828 IO::AIO::poll_wait, IO::AIO::poll_cb 1864 IO::AIO::poll_wait, IO::AIO::poll_cb
1829 while IO::AIO::nreqs; 1865 while IO::AIO::nreqs;
1830 1866
1867This function can be useful at program aborts, to make sure outstanding
1868I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1869this function on normal exits), or when you are merely using C<IO::AIO>
1870for its more advanced functions, rather than for async I/O, e.g.:
1871
1872 my ($dirs, $nondirs);
1873 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1874 IO::AIO::flush;
1875 # $dirs, $nondirs are now set
1876
1831=item IO::AIO::max_poll_reqs $nreqs 1877=item IO::AIO::max_poll_reqs $nreqs
1832 1878
1833=item IO::AIO::max_poll_time $seconds 1879=item IO::AIO::max_poll_time $seconds
1834 1880
1835These set the maximum number of requests (default C<0>, meaning infinity) 1881These set the maximum number of requests (default C<0>, meaning infinity)
… …
1861 poll => 'r', nice => 1, 1907 poll => 'r', nice => 1,
1862 cb => &IO::AIO::poll_cb); 1908 cb => &IO::AIO::poll_cb);
1863 1909
1864=back 1910=back
1865 1911
1912
1866=head3 CONTROLLING THE NUMBER OF THREADS 1913=head3 CONTROLLING THE NUMBER OF THREADS
1867 1914
1868=over 1915=over
1869 1916
1870=item IO::AIO::min_parallel $nthreads 1917=item IO::AIO::min_parallel $nthreads
… …
1935 1982
1936This is a very bad function to use in interactive programs because it 1983This is a very bad function to use in interactive programs because it
1937blocks, and a bad way to reduce concurrency because it is inexact: Better 1984blocks, and a bad way to reduce concurrency because it is inexact: Better
1938use an C<aio_group> together with a feed callback. 1985use an C<aio_group> together with a feed callback.
1939 1986
1940It's main use is in scripts without an event loop - when you want to stat 1987Its main use is in scripts without an event loop - when you want to stat
1941a lot of files, you can write somehting like this: 1988a lot of files, you can write something like this:
1942 1989
1943 IO::AIO::max_outstanding 32; 1990 IO::AIO::max_outstanding 32;
1944 1991
1945 for my $path (...) { 1992 for my $path (...) {
1946 aio_stat $path , ...; 1993 aio_stat $path , ...;
… …
1957The default value for C<max_outstanding> is very large, so there is no 2004The default value for C<max_outstanding> is very large, so there is no
1958practical limit on the number of outstanding requests. 2005practical limit on the number of outstanding requests.
1959 2006
1960=back 2007=back
1961 2008
2009
1962=head3 STATISTICAL INFORMATION 2010=head3 STATISTICAL INFORMATION
1963 2011
1964=over 2012=over
1965 2013
1966=item IO::AIO::nreqs 2014=item IO::AIO::nreqs
… …
1983Returns the number of requests currently in the pending state (executed, 2031Returns the number of requests currently in the pending state (executed,
1984but not yet processed by poll_cb). 2032but not yet processed by poll_cb).
1985 2033
1986=back 2034=back
1987 2035
2036
2037=head3 SUBSECOND STAT TIME ACCESS
2038
2039Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2040generally find access/modification and change times with subsecond time
2041accuracy of the system supports it, but perl's built-in functions only
2042return the integer part.
2043
2044The following functions return the timestamps of the most recent
2045stat with subsecond precision on most systems and work both after
2046C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2047value is only meaningful after a successful C<stat>/C<lstat> call, or
2048during/after a successful C<aio_stat>/C<aio_lstat> callback.
2049
2050This is similar to the L<Time::HiRes> C<stat> functions, but can return
2051full resolution without rounding and work with standard perl C<stat>,
2052alleviating the need to call the special C<Time::HiRes> functions, which
2053do not act like their perl counterparts.
2054
2055On operating systems or file systems where subsecond time resolution is
2056not supported or could not be detected, a fractional part of C<0> is
2057returned, so it is always safe to call these functions.
2058
2059=over 4
2060
2061=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2062
2063Return the access, modication, change or birth time, respectively,
2064including fractional part. Due to the limited precision of floating point,
2065the accuracy on most platforms is only a bit better than milliseconds
2066for times around now - see the I<nsec> function family, below, for full
2067accuracy.
2068
2069File birth time is only available when the OS and perl support it (on
2070FreeBSD and NetBSD at the time of this writing, although support is
2071adaptive, so if your OS/perl gains support, IO::AIO can take avdantage of
2072it). On systems where it isn't available, C<0> is currently returned, but
2073this might change to C<undef> in a future version.
2074
2075=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2076
2077Returns access, modification, change and birth time all in one go, and
2078maybe more times in the future version.
2079
2080=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2081
2082Return the fractional access, modifcation, change or birth time, in nanoseconds,
2083as an integer in the range C<0> to C<999999999>.
2084
2085Note that no accessors are provided for access, modification and
2086change times - you need to get those from C<stat _> if required (C<int
2087IO::AIO::st_atime> and so on will I<not> generally give you the correct
2088value).
2089
2090=item $seconds = IO::AIO::st_btimesec
2091
2092The (integral) seconds part of the file birth time, if available.
2093
2094=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2095
2096Like the functions above, but returns all four times in one go (and maybe
2097more in future versions).
2098
2099=item $counter = IO::AIO::st_gen
2100
2101Returns the generation counter (in practice this is just a random number)
2102of the file. This is only available on platforms which have this member in
2103their C<struct stat> (most BSDs at the time of this writing) and generally
2104only to the root usert. If unsupported, C<0> is returned, but this might
2105change to C<undef> in a future version.
2106
2107=back
2108
2109Example: print the high resolution modification time of F</etc>, using
2110C<stat>, and C<IO::AIO::aio_stat>.
2111
2112 if (stat "/etc") {
2113 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2114 }
2115
2116 IO::AIO::aio_stat "/etc", sub {
2117 $_[0]
2118 and return;
2119
2120 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2121 };
2122
2123 IO::AIO::flush;
2124
2125Output of the awbove on my system, showing reduced and full accuracy:
2126
2127 stat(/etc) mtime: 1534043702.020808
2128 aio_stat(/etc) mtime: 1534043702.020807792
2129
2130
1988=head3 MISCELLANEOUS FUNCTIONS 2131=head3 MISCELLANEOUS FUNCTIONS
1989 2132
1990IO::AIO implements some functions that might be useful, but are not 2133IO::AIO implements some functions that are useful when you want to use
1991asynchronous. 2134some "Advanced I/O" function not available to in Perl, without going the
2135"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2136counterpart.
1992 2137
1993=over 4 2138=over 4
2139
2140=item $numfd = IO::AIO::get_fdlimit
2141
2142This function is I<EXPERIMENTAL> and subject to change.
2143
2144Tries to find the current file descriptor limit and returns it, or
2145C<undef> and sets C<$!> in case of an error. The limit is one larger than
2146the highest valid file descriptor number.
2147
2148=item IO::AIO::min_fdlimit [$numfd]
2149
2150This function is I<EXPERIMENTAL> and subject to change.
2151
2152Try to increase the current file descriptor limit(s) to at least C<$numfd>
2153by changing the soft or hard file descriptor resource limit. If C<$numfd>
2154is missing, it will try to set a very high limit, although this is not
2155recommended when you know the actual minimum that you require.
2156
2157If the limit cannot be raised enough, the function makes a best-effort
2158attempt to increase the limit as much as possible, using various
2159tricks, while still failing. You can query the resulting limit using
2160C<IO::AIO::get_fdlimit>.
2161
2162If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2163true.
1994 2164
1995=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2165=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1996 2166
1997Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2167Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1998but is blocking (this makes most sense if you know the input data is 2168but is blocking (this makes most sense if you know the input data is
… …
2015=item IO::AIO::madvise $scalar, $offset, $len, $advice 2185=item IO::AIO::madvise $scalar, $offset, $len, $advice
2016 2186
2017Simply calls the C<posix_madvise> function (see its 2187Simply calls the C<posix_madvise> function (see its
2018manpage for details). The following advice constants are 2188manpage for details). The following advice constants are
2019available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2189available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2020C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2190C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2191C<IO::AIO::MADV_DONTNEED>.
2192
2193If C<$offset> is negative, counts from the end. If C<$length> is negative,
2194the remaining length of the C<$scalar> is used. If possible, C<$length>
2195will be reduced to fit into the C<$scalar>.
2021 2196
2022On systems that do not implement C<posix_madvise>, this function returns 2197On systems that do not implement C<posix_madvise>, this function returns
2023ENOSYS, otherwise the return value of C<posix_madvise>. 2198ENOSYS, otherwise the return value of C<posix_madvise>.
2024 2199
2025=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2200=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2027Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2202Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2028$scalar (see its manpage for details). The following protect 2203$scalar (see its manpage for details). The following protect
2029constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2204constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2030C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2205C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2031 2206
2207If C<$offset> is negative, counts from the end. If C<$length> is negative,
2208the remaining length of the C<$scalar> is used. If possible, C<$length>
2209will be reduced to fit into the C<$scalar>.
2210
2032On systems that do not implement C<mprotect>, this function returns 2211On systems that do not implement C<mprotect>, this function returns
2033ENOSYS, otherwise the return value of C<mprotect>. 2212ENOSYS, otherwise the return value of C<mprotect>.
2034 2213
2035=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2214=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2036 2215
2037Memory-maps a file (or anonymous memory range) and attaches it to the 2216Memory-maps a file (or anonymous memory range) and attaches it to the
2038given C<$scalar>, which will act like a string scalar. Returns true on 2217given C<$scalar>, which will act like a string scalar. Returns true on
2039success, and false otherwise. 2218success, and false otherwise.
2040 2219
2220The scalar must exist, but its contents do not matter - this means you
2221cannot use a nonexistant array or hash element. When in doubt, C<undef>
2222the scalar first.
2223
2041The only operations allowed on the scalar are C<substr>/C<vec> that don't 2224The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2042change the string length, and most read-only operations such as copying it 2225which don't change the string length, and most read-only operations such
2043or searching it with regexes and so on. 2226as copying it or searching it with regexes and so on.
2044 2227
2045Anything else is unsafe and will, at best, result in memory leaks. 2228Anything else is unsafe and will, at best, result in memory leaks.
2046 2229
2047The memory map associated with the C<$scalar> is automatically removed 2230The memory map associated with the C<$scalar> is automatically removed
2048when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2231when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2049C<IO::AIO::munmap> functions are called. 2232or C<IO::AIO::munmap> functions are called on it.
2050 2233
2051This calls the C<mmap>(2) function internally. See your system's manual 2234This calls the C<mmap>(2) function internally. See your system's manual
2052page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2235page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2053 2236
2054The C<$length> must be larger than zero and smaller than the actual 2237The C<$length> must be larger than zero and smaller than the actual
2055filesize. 2238filesize.
2056 2239
2057C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2240C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2058C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2241C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2059 2242
2060C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2243C<$flags> can be a combination of
2061C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2244C<IO::AIO::MAP_SHARED> or
2062not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2245C<IO::AIO::MAP_PRIVATE>,
2246or a number of system-specific flags (when not available, the are C<0>):
2063(which is set to C<MAP_ANON> if your system only provides this 2247C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2064constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2248C<IO::AIO::MAP_LOCKED>,
2065C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2249C<IO::AIO::MAP_NORESERVE>,
2250C<IO::AIO::MAP_POPULATE>,
2066C<IO::AIO::MAP_NONBLOCK> 2251C<IO::AIO::MAP_NONBLOCK>,
2252C<IO::AIO::MAP_FIXED>,
2253C<IO::AIO::MAP_GROWSDOWN>,
2254C<IO::AIO::MAP_32BIT>,
2255C<IO::AIO::MAP_HUGETLB> or
2256C<IO::AIO::MAP_STACK>.
2067 2257
2068If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2258If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2069 2259
2070C<$offset> is the offset from the start of the file - it generally must be 2260C<$offset> is the offset from the start of the file - it generally must be
2071a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2261a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2084 my $fast_md5 = md5 $data; 2274 my $fast_md5 = md5 $data;
2085 2275
2086=item IO::AIO::munmap $scalar 2276=item IO::AIO::munmap $scalar
2087 2277
2088Removes a previous mmap and undefines the C<$scalar>. 2278Removes a previous mmap and undefines the C<$scalar>.
2279
2280=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2281
2282Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2283been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2284C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2285
2286Returns true if successful, and false otherwise. If the underlying mmapped
2287region has changed address, then the true value has the numerical value
2288C<1>, otherwise it has the numerical value C<0>:
2289
2290 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2291 or die "mremap: $!";
2292
2293 if ($success*1) {
2294 warn "scalar has chanegd address in memory\n";
2295 }
2296
2297C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2298implemented, but not supported and might go away in a future version.
2299
2300On systems where this call is not supported or is not emulated, this call
2301returns falls and sets C<$!> to C<ENOSYS>.
2089 2302
2090=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2303=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2091 2304
2092Calls the C<munlock> function, undoing the effects of a previous 2305Calls the C<munlock> function, undoing the effects of a previous
2093C<aio_mlock> call (see its description for details). 2306C<aio_mlock> call (see its description for details).
… …
2114 2327
2115See the C<splice(2)> manpage for details. 2328See the C<splice(2)> manpage for details.
2116 2329
2117=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2330=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2118 2331
2119Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2332Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2120description for C<IO::AIO::splice> above for details. 2333description for C<IO::AIO::splice> above for details.
2334
2335=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2336
2337Attempts to query or change the pipe buffer size. Obviously works only
2338on pipes, and currently works only on GNU/Linux systems, and fails with
2339C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2340size on other systems, drop me a note.
2341
2342=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2343
2344This is a direct interface to the Linux L<pipe2(2)> system call. If
2345C<$flags> is missing or C<0>, then this should be the same as a call to
2346perl's built-in C<pipe> function and create a new pipe, and works on
2347systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2348(..., 4096, O_BINARY)>.
2349
2350If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2351the given flags (Linux 2.6.27, glibc 2.9).
2352
2353On success, the read and write file handles are returned.
2354
2355On error, nothing will be returned. If the pipe2 syscall is missing and
2356C<$flags> is non-zero, fails with C<ENOSYS>.
2357
2358Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2359time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2360C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2361
2362Example: create a pipe race-free w.r.t. threads and fork:
2363
2364 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2365 or die "pipe2: $!\n";
2366
2367=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2368
2369This is a direct interface to the Linux L<eventfd(2)> system call. The
2370(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2371
2372On success, the new eventfd filehandle is returned, otherwise returns
2373C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2374
2375Please refer to L<eventfd(2)> for more info on this call.
2376
2377The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2378C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2379
2380Example: create a new eventfd filehandle:
2381
2382 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2383 or die "eventfd: $!\n";
2384
2385=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2386
2387This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2388(unhelpful) default for C<$flags> is C<0>.
2389
2390On success, the new timerfd filehandle is returned, otherwise returns
2391C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2392
2393Please refer to L<timerfd_create(2)> for more info on this call.
2394
2395The following C<$clockid> values are
2396available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2397C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2398C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2399C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2400
2401The following C<$flags> values are available (Linux
24022.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2403
2404Example: create a new timerfd and set it to one-second repeated alarms,
2405then wait for two alarms:
2406
2407 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2408 or die "timerfd_create: $!\n";
2409
2410 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2411 or die "timerfd_settime: $!\n";
2412
2413 for (1..2) {
2414 8 == sysread $fh, my $buf, 8
2415 or die "timerfd read failure\n";
2416
2417 printf "number of expirations (likely 1): %d\n",
2418 unpack "Q", $buf;
2419 }
2420
2421=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2422
2423This is a direct interface to the Linux L<timerfd_settime(2)> system
2424call. Please refer to its manpage for more info on this call.
2425
2426The new itimerspec is specified using two (possibly fractional) second
2427values, C<$new_interval> and C<$new_value>).
2428
2429On success, the current interval and value are returned (as per
2430C<timerfd_gettime>). On failure, the empty list is returned.
2431
2432The following C<$flags> values are
2433available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2434C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2435
2436See C<IO::AIO::timerfd_create> for a full example.
2437
2438=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2439
2440This is a direct interface to the Linux L<timerfd_gettime(2)> system
2441call. Please refer to its manpage for more info on this call.
2442
2443On success, returns the current values of interval and value for the given
2444timerfd (as potentially fractional second values). On failure, the empty
2445list is returned.
2121 2446
2122=back 2447=back
2123 2448
2124=cut 2449=cut
2125 2450
… …
2191the process will result in undefined behaviour. Calling it at any time 2516the process will result in undefined behaviour. Calling it at any time
2192will also result in any undefined (by POSIX) behaviour. 2517will also result in any undefined (by POSIX) behaviour.
2193 2518
2194=back 2519=back
2195 2520
2521=head2 LINUX-SPECIFIC CALLS
2522
2523When a call is documented as "linux-specific" then this means it
2524originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2525availability and compatibility of such calls regardless of the platform
2526it is compiled on, so platforms such as FreeBSD which often implement
2527these calls will work. When in doubt, call them and see if they fail wth
2528C<ENOSYS>.
2529
2196=head2 MEMORY USAGE 2530=head2 MEMORY USAGE
2197 2531
2198Per-request usage: 2532Per-request usage:
2199 2533
2200Each aio request uses - depending on your architecture - around 100-200 2534Each aio request uses - depending on your architecture - around 100-200
… …
2212temporary buffers, and each thread requires a stack and other data 2546temporary buffers, and each thread requires a stack and other data
2213structures (usually around 16k-128k, depending on the OS). 2547structures (usually around 16k-128k, depending on the OS).
2214 2548
2215=head1 KNOWN BUGS 2549=head1 KNOWN BUGS
2216 2550
2217Known bugs will be fixed in the next release. 2551Known bugs will be fixed in the next release :)
2552
2553=head1 KNOWN ISSUES
2554
2555Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2556or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2557non-created hash slots or other scalars I didn't think of. It's best to
2558avoid such and either use scalar variables or making sure that the scalar
2559exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2560
2561I am not sure anything can be done about this, so this is considered a
2562known issue, rather than a bug.
2218 2563
2219=head1 SEE ALSO 2564=head1 SEE ALSO
2220 2565
2221L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2566L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2222more natural syntax. 2567more natural syntax.

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