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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.240 by root, Mon Dec 17 06:18:39 2012 UTC vs.
Revision 1.287 by root, Tue Jul 24 04:58:59 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 = 4.42;
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)
… …
603 namemax => 255, 613 namemax => 255,
604 frsize => 1024, 614 frsize => 1024,
605 fsid => 1810 615 fsid => 1810
606 } 616 }
607 617
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) 618=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
691 619
692Works like perl's C<utime> function (including the special case of $atime 620Works like perl's C<utime> function (including the special case of $atime
693and $mtime being undef). Fractional times are supported if the underlying 621and $mtime being undef). Fractional times are supported if the underlying
694syscalls support them. 622syscalls support them.
… …
723Works like truncate(2) or ftruncate(2). 651Works like truncate(2) or ftruncate(2).
724 652
725 653
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 654=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727 655
728Allocates or freed disk space according to the C<$mode> argument. See the 656Allocates or frees disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details. 657linux C<fallocate> documentation for details.
730 658
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 659C<$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 | 660space, 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. 661to deallocate a file range.
662
663IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
664(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
665C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
666to unshare shared blocks (see your L<fallocate(2)> manpage).
734 667
735The file system block size used by C<fallocate> is presumably the 668The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>. 669C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
670can dictate other limitations.
737 671
738If C<fallocate> isn't available or cannot be emulated (currently no 672If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 673emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740 674
741 675
… …
795=item aio_rename $srcpath, $dstpath, $callback->($status) 729=item aio_rename $srcpath, $dstpath, $callback->($status)
796 730
797Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 731Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
798rename(2) and call the callback with the result code. 732rename(2) and call the callback with the result code.
799 733
734On systems that support the AIO::WD working directory abstraction
735natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
736of failing, C<rename> is called on the absolute path of C<$wd>.
737
738
739=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
740
741Basically a version of C<aio_rename> with an additional C<$flags>
742argument. Calling this with C<$flags=0> is the same as calling
743C<aio_rename>.
744
745Non-zero flags are currently only supported on GNU/Linux systems that
746support renameat2. Other systems fail with C<ENOSYS> in this case.
747
748The following constants are available (missing ones are, as usual C<0>),
749see renameat2(2) for details:
750
751C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
752and C<IO::AIO::RENAME_WHITEOUT>.
753
800 754
801=item aio_mkdir $pathname, $mode, $callback->($status) 755=item aio_mkdir $pathname, $mode, $callback->($status)
802 756
803Asynchronously mkdir (create) a directory and call the callback with 757Asynchronously mkdir (create) a directory and call the callback with
804the result code. C<$mode> will be modified by the umask at the time the 758the result code. C<$mode> will be modified by the umask at the time the
… …
808=item aio_rmdir $pathname, $callback->($status) 762=item aio_rmdir $pathname, $callback->($status)
809 763
810Asynchronously rmdir (delete) a directory and call the callback with the 764Asynchronously rmdir (delete) a directory and call the callback with the
811result code. 765result code.
812 766
767On systems that support the AIO::WD working directory abstraction
768natively, the case C<[$wd, "."]> is specialcased - instead of failing,
769C<rmdir> is called on the absolute path of C<$wd>.
770
813 771
814=item aio_readdir $pathname, $callback->($entries) 772=item aio_readdir $pathname, $callback->($entries)
815 773
816Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 774Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
817directory (i.e. opendir + readdir + closedir). The entries will not be 775directory (i.e. opendir + readdir + closedir). The entries will not be
… …
832 790
833=over 4 791=over 4
834 792
835=item IO::AIO::READDIR_DENTS 793=item IO::AIO::READDIR_DENTS
836 794
837When this flag is off, then the callback gets an arrayref consisting of 795Normally the callback gets an arrayref consisting of names only (as
838names only (as with C<aio_readdir>), otherwise it gets an arrayref with 796with C<aio_readdir>). If this flag is set, then the callback gets an
839C<[$name, $type, $inode]> arrayrefs, each describing a single directory 797arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
840entry in more detail. 798single directory entry in more detail:
841 799
842C<$name> is the name of the entry. 800C<$name> is the name of the entry.
843 801
844C<$type> is one of the C<IO::AIO::DT_xxx> constants: 802C<$type> is one of the C<IO::AIO::DT_xxx> constants:
845 803
846C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 804C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
847C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 805C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
848C<IO::AIO::DT_WHT>. 806C<IO::AIO::DT_WHT>.
849 807
850C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 808C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
851know, you have to run stat yourself. Also, for speed reasons, the C<$type> 809to know, you have to run stat yourself. Also, for speed/memory reasons,
852scalars are read-only: you can not modify them. 810the C<$type> scalars are read-only: you must not modify them.
853 811
854C<$inode> is the inode number (which might not be exact on systems with 64 812C<$inode> is the inode number (which might not be exact on systems with 64
855bit inode numbers and 32 bit perls). This field has unspecified content on 813bit inode numbers and 32 bit perls). This field has unspecified content on
856systems that do not deliver the inode information. 814systems that do not deliver the inode information.
857 815
… …
868short names are tried first. 826short names are tried first.
869 827
870=item IO::AIO::READDIR_STAT_ORDER 828=item IO::AIO::READDIR_STAT_ORDER
871 829
872When this flag is set, then the names will be returned in an order 830When this flag is set, then the names will be returned in an order
873suitable for stat()'ing each one. That is, when you plan to stat() 831suitable for stat()'ing each one. That is, when you plan to stat() most or
874all files in the given directory, then the returned order will likely 832all files in the given directory, then the returned order will likely be
875be fastest. 833faster.
876 834
877If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 835If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
878the likely dirs come first, resulting in a less optimal stat order. 836then the likely dirs come first, resulting in a less optimal stat order
837for stat'ing all entries, but likely a more optimal order for finding
838subdirectories.
879 839
880=item IO::AIO::READDIR_FOUND_UNKNOWN 840=item IO::AIO::READDIR_FOUND_UNKNOWN
881 841
882This flag should not be set when calling C<aio_readdirx>. Instead, it 842This flag should not be set when calling C<aio_readdirx>. Instead, it
883is being set by C<aio_readdirx>, when any of the C<$type>'s found were 843is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
885C<$type>'s are known, which can be used to speed up some algorithms. 845C<$type>'s are known, which can be used to speed up some algorithms.
886 846
887=back 847=back
888 848
889 849
850=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
851
852Opens, reads and closes the given file. The data is put into C<$data>,
853which is resized as required.
854
855If C<$offset> is negative, then it is counted from the end of the file.
856
857If C<$length> is zero, then the remaining length of the file is
858used. Also, in this case, the same limitations to modifying C<$data> apply
859as when IO::AIO::mmap is used, i.e. it must only be modified in-place
860with C<substr>. If the size of the file is known, specifying a non-zero
861C<$length> results in a performance advantage.
862
863This request is similar to the older C<aio_load> request, but since it is
864a single request, it might be more efficient to use.
865
866Example: load F</etc/passwd> into C<$passwd>.
867
868 my $passwd;
869 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
870 $_[0] >= 0
871 or die "/etc/passwd: $!\n";
872
873 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
874 print $passwd;
875 };
876 IO::AIO::flush;
877
878
890=item aio_load $pathname, $data, $callback->($status) 879=item aio_load $pathname, $data, $callback->($status)
891 880
892This is a composite request that tries to fully load the given file into 881This is a composite request that tries to fully load the given file into
893memory. Status is the same as with aio_read. 882memory. Status is the same as with aio_read.
883
884Using C<aio_slurp> might be more efficient, as it is a single request.
894 885
895=cut 886=cut
896 887
897sub aio_load($$;$) { 888sub aio_load($$;$) {
898 my ($path, undef, $cb) = @_; 889 my ($path, undef, $cb) = @_;
… …
918=item aio_copy $srcpath, $dstpath, $callback->($status) 909=item aio_copy $srcpath, $dstpath, $callback->($status)
919 910
920Try to copy the I<file> (directories not supported as either source or 911Try to copy the I<file> (directories not supported as either source or
921destination) from C<$srcpath> to C<$dstpath> and call the callback with 912destination) from C<$srcpath> to C<$dstpath> and call the callback with
922a status of C<0> (ok) or C<-1> (error, see C<$!>). 913a status of C<0> (ok) or C<-1> (error, see C<$!>).
914
915Existing destination files will be truncated.
923 916
924This is a composite request that creates the destination file with 917This is a composite request that creates the destination file with
925mode 0200 and copies the contents of the source file into it using 918mode 0200 and copies the contents of the source file into it using
926C<aio_sendfile>, followed by restoring atime, mtime, access mode and 919C<aio_sendfile>, followed by restoring atime, mtime, access mode and
927uid/gid, in that order. 920uid/gid, in that order.
… …
1037Scans a directory (similar to C<aio_readdir>) but additionally tries to 1030Scans a directory (similar to C<aio_readdir>) but additionally tries to
1038efficiently separate the entries of directory C<$path> into two sets of 1031efficiently separate the entries of directory C<$path> into two sets of
1039names, directories you can recurse into (directories), and ones you cannot 1032names, directories you can recurse into (directories), and ones you cannot
1040recurse into (everything else, including symlinks to directories). 1033recurse into (everything else, including symlinks to directories).
1041 1034
1042C<aio_scandir> is a composite request that creates of many sub requests_ 1035C<aio_scandir> is a composite request that generates many sub requests.
1043C<$maxreq> specifies the maximum number of outstanding aio requests that 1036C<$maxreq> specifies the maximum number of outstanding aio requests that
1044this function generates. If it is C<< <= 0 >>, then a suitable default 1037this function generates. If it is C<< <= 0 >>, then a suitable default
1045will be chosen (currently 4). 1038will be chosen (currently 4).
1046 1039
1047On error, the callback is called without arguments, otherwise it receives 1040On error, the callback is called without arguments, otherwise it receives
… …
1213 }; 1206 };
1214 1207
1215 $grp 1208 $grp
1216} 1209}
1217 1210
1211=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1212
1213=item aio_ioctl $fh, $request, $buf, $callback->($status)
1214
1215These work just like the C<fcntl> and C<ioctl> built-in functions, except
1216they execute asynchronously and pass the return value to the callback.
1217
1218Both calls can be used for a lot of things, some of which make more sense
1219to run asynchronously in their own thread, while some others make less
1220sense. For example, calls that block waiting for external events, such
1221as locking, will also lock down an I/O thread while it is waiting, which
1222can deadlock the whole I/O system. At the same time, there might be no
1223alternative to using a thread to wait.
1224
1225So in general, you should only use these calls for things that do
1226(filesystem) I/O, not for things that wait for other events (network,
1227other processes), although if you are careful and know what you are doing,
1228you still can.
1229
1230The following constants are available (missing ones are, as usual C<0>):
1231
1232C<F_DUPFD_CLOEXEC>,
1233
1234C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1235
1236C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1237
1238C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1239C<FS_IOC_FIEMAP>.
1240
1241C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1242C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1243
1244C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1245C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1246C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1247C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1248C<FS_FL_USER_MODIFIABLE>.
1249
1250C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1251C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1252C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1253C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1254
1218=item aio_sync $callback->($status) 1255=item aio_sync $callback->($status)
1219 1256
1220Asynchronously call sync and call the callback when finished. 1257Asynchronously call sync and call the callback when finished.
1221 1258
1222=item aio_fsync $fh, $callback->($status) 1259=item aio_fsync $fh, $callback->($status)
… …
1290 }; 1327 };
1291 1328
1292 $grp 1329 $grp
1293} 1330}
1294 1331
1295=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1332=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1296 1333
1297This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1334This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1298scalars (see the C<IO::AIO::mmap> function, although it also works on data 1335scalars (see the C<IO::AIO::mmap> function, although it also works on data
1299scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1336scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1300scalar must only be modified in-place while an aio operation is pending on 1337scalar must only be modified in-place while an aio operation is pending on
… …
1302 1339
1303It calls the C<msync> function of your OS, if available, with the memory 1340It calls the C<msync> function of your OS, if available, with the memory
1304area starting at C<$offset> in the string and ending C<$length> bytes 1341area starting at C<$offset> in the string and ending C<$length> bytes
1305later. If C<$length> is negative, counts from the end, and if C<$length> 1342later. If C<$length> is negative, counts from the end, and if C<$length>
1306is C<undef>, then it goes till the end of the string. The flags can be 1343is C<undef>, then it goes till the end of the string. The flags can be
1307a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1344either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1308C<IO::AIO::MS_SYNC>. 1345C<IO::AIO::MS_INVALIDATE>.
1309 1346
1310=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1347=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1311 1348
1312This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1349This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1313scalars. 1350scalars.
… …
1396C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1433C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1397C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1434C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1398C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1435C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1399C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1436C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1400 1437
1401At the time of this writing (Linux 3.2), this requets is unreliable unless 1438At the time of this writing (Linux 3.2), this request is unreliable unless
1402C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1439C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1403it to return all extents of a range for files with large number of 1440it to return all extents of a range for files with a large number of
1404extents. The code works around all these issues if C<$count> is undef. 1441extents. The code (only) works around all these issues if C<$count> is
1442C<undef>.
1405 1443
1406=item aio_group $callback->(...) 1444=item aio_group $callback->(...)
1407 1445
1408This is a very special aio request: Instead of doing something, it is a 1446This is a very special aio request: Instead of doing something, it is a
1409container for other aio requests, which is useful if you want to bundle 1447container for other aio requests, which is useful if you want to bundle
… …
1493 aio_stat [$etcdir, "passwd"], sub { 1531 aio_stat [$etcdir, "passwd"], sub {
1494 # yay 1532 # yay
1495 }; 1533 };
1496 }; 1534 };
1497 1535
1498That C<aio_wd> is a request and not a normal function shows that creating 1536The fact that C<aio_wd> is a request and not a normal function shows that
1499an IO::AIO::WD object is itself a potentially blocking operation, which is 1537creating an IO::AIO::WD object is itself a potentially blocking operation,
1500why it is done asynchronously. 1538which is why it is done asynchronously.
1501 1539
1502To stat the directory obtained with C<aio_wd> above, one could write 1540To stat the directory obtained with C<aio_wd> above, one could write
1503either of the following three request calls: 1541either of the following three request calls:
1504 1542
1505 aio_lstat "/etc" , sub { ... # pathname as normal string 1543 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1522There are some caveats: when directories get renamed (or deleted), the 1560There are some caveats: when directories get renamed (or deleted), the
1523pathname string doesn't change, so will point to the new directory (or 1561pathname string doesn't change, so will point to the new directory (or
1524nowhere at all), while the directory fd, if available on the system, 1562nowhere at all), while the directory fd, if available on the system,
1525will still point to the original directory. Most functions accepting a 1563will still point to the original directory. Most functions accepting a
1526pathname will use the directory fd on newer systems, and the string on 1564pathname will use the directory fd on newer systems, and the string on
1527older systems. Some functions (such as realpath) will always rely on the 1565older systems. Some functions (such as C<aio_realpath>) will always rely on
1528string form of the pathname. 1566the string form of the pathname.
1529 1567
1530So this functionality is mainly useful to get some protection against 1568So this functionality is mainly useful to get some protection against
1531C<chdir>, to easily get an absolute path out of a relative path for future 1569C<chdir>, to easily get an absolute path out of a relative path for future
1532reference, and to speed up doing many operations in the same directory 1570reference, and to speed up doing many operations in the same directory
1533(e.g. when stat'ing all files in a directory). 1571(e.g. when stat'ing all files in a directory).
… …
1548passing C<undef> as working directory component of a pathname fails the 1586passing C<undef> as working directory component of a pathname fails the
1549request with C<ENOENT>, there is often no need for error checking in the 1587request with C<ENOENT>, there is often no need for error checking in the
1550C<aio_wd> callback, as future requests using the value will fail in the 1588C<aio_wd> callback, as future requests using the value will fail in the
1551expected way. 1589expected way.
1552 1590
1553If this call isn't available because your OS lacks it or it couldn't be
1554detected, it will be emulated by calling C<fsync> instead.
1555
1556=item IO::AIO::CWD 1591=item IO::AIO::CWD
1557 1592
1558This is a compiletime constant (object) that represents the process 1593This is a compiletime constant (object) that represents the process
1559current working directory. 1594current working directory.
1560 1595
… …
1572 1607
1573 aio_realpath $wd, sub { 1608 aio_realpath $wd, sub {
1574 warn "path is $_[0]\n"; 1609 warn "path is $_[0]\n";
1575 }; 1610 };
1576 1611
1612Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1613sometimes, fall back to using an absolue path.
1577 1614
1578=head2 IO::AIO::REQ CLASS 1615=head2 IO::AIO::REQ CLASS
1579 1616
1580All non-aggregate C<aio_*> functions return an object of this class when 1617All non-aggregate C<aio_*> functions return an object of this class when
1581called in non-void context. 1618called in non-void context.
… …
1925 1962
1926This is a very bad function to use in interactive programs because it 1963This is a very bad function to use in interactive programs because it
1927blocks, and a bad way to reduce concurrency because it is inexact: Better 1964blocks, and a bad way to reduce concurrency because it is inexact: Better
1928use an C<aio_group> together with a feed callback. 1965use an C<aio_group> together with a feed callback.
1929 1966
1930It's main use is in scripts without an event loop - when you want to stat 1967Its main use is in scripts without an event loop - when you want to stat
1931a lot of files, you can write somehting like this: 1968a lot of files, you can write something like this:
1932 1969
1933 IO::AIO::max_outstanding 32; 1970 IO::AIO::max_outstanding 32;
1934 1971
1935 for my $path (...) { 1972 for my $path (...) {
1936 aio_stat $path , ...; 1973 aio_stat $path , ...;
… …
1975 2012
1976=back 2013=back
1977 2014
1978=head3 MISCELLANEOUS FUNCTIONS 2015=head3 MISCELLANEOUS FUNCTIONS
1979 2016
1980IO::AIO implements some functions that might be useful, but are not 2017IO::AIO implements some functions that are useful when you want to use
1981asynchronous. 2018some "Advanced I/O" function not available to in Perl, without going the
2019"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2020counterpart.
1982 2021
1983=over 4 2022=over 4
2023
2024=item $numfd = IO::AIO::get_fdlimit
2025
2026This function is I<EXPERIMENTAL> and subject to change.
2027
2028Tries to find the current file descriptor limit and returns it, or
2029C<undef> and sets C<$!> in case of an error. The limit is one larger than
2030the highest valid file descriptor number.
2031
2032=item IO::AIO::min_fdlimit [$numfd]
2033
2034This function is I<EXPERIMENTAL> and subject to change.
2035
2036Try to increase the current file descriptor limit(s) to at least C<$numfd>
2037by changing the soft or hard file descriptor resource limit. If C<$numfd>
2038is missing, it will try to set a very high limit, although this is not
2039recommended when you know the actual minimum that you require.
2040
2041If the limit cannot be raised enough, the function makes a best-effort
2042attempt to increase the limit as much as possible, using various
2043tricks, while still failing. You can query the resulting limit using
2044C<IO::AIO::get_fdlimit>.
2045
2046If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2047true.
1984 2048
1985=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2049=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1986 2050
1987Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2051Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1988but is blocking (this makes most sense if you know the input data is 2052but is blocking (this makes most sense if you know the input data is
… …
2005=item IO::AIO::madvise $scalar, $offset, $len, $advice 2069=item IO::AIO::madvise $scalar, $offset, $len, $advice
2006 2070
2007Simply calls the C<posix_madvise> function (see its 2071Simply calls the C<posix_madvise> function (see its
2008manpage for details). The following advice constants are 2072manpage for details). The following advice constants are
2009available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2073available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2010C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2074C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2075C<IO::AIO::MADV_DONTNEED>.
2076
2077If C<$offset> is negative, counts from the end. If C<$length> is negative,
2078the remaining length of the C<$scalar> is used. If possible, C<$length>
2079will be reduced to fit into the C<$scalar>.
2011 2080
2012On systems that do not implement C<posix_madvise>, this function returns 2081On systems that do not implement C<posix_madvise>, this function returns
2013ENOSYS, otherwise the return value of C<posix_madvise>. 2082ENOSYS, otherwise the return value of C<posix_madvise>.
2014 2083
2015=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2084=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2017Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2086Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2018$scalar (see its manpage for details). The following protect 2087$scalar (see its manpage for details). The following protect
2019constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2088constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2020C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2089C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2021 2090
2091If C<$offset> is negative, counts from the end. If C<$length> is negative,
2092the remaining length of the C<$scalar> is used. If possible, C<$length>
2093will be reduced to fit into the C<$scalar>.
2094
2022On systems that do not implement C<mprotect>, this function returns 2095On systems that do not implement C<mprotect>, this function returns
2023ENOSYS, otherwise the return value of C<mprotect>. 2096ENOSYS, otherwise the return value of C<mprotect>.
2024 2097
2025=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2098=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2026 2099
2027Memory-maps a file (or anonymous memory range) and attaches it to the 2100Memory-maps a file (or anonymous memory range) and attaches it to the
2028given C<$scalar>, which will act like a string scalar. Returns true on 2101given C<$scalar>, which will act like a string scalar. Returns true on
2029success, and false otherwise. 2102success, and false otherwise.
2030 2103
2104The scalar must exist, but its contents do not matter - this means you
2105cannot use a nonexistant array or hash element. When in doubt, C<undef>
2106the scalar first.
2107
2031The only operations allowed on the scalar are C<substr>/C<vec> that don't 2108The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2032change the string length, and most read-only operations such as copying it 2109which don't change the string length, and most read-only operations such
2033or searching it with regexes and so on. 2110as copying it or searching it with regexes and so on.
2034 2111
2035Anything else is unsafe and will, at best, result in memory leaks. 2112Anything else is unsafe and will, at best, result in memory leaks.
2036 2113
2037The memory map associated with the C<$scalar> is automatically removed 2114The memory map associated with the C<$scalar> is automatically removed
2038when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2115when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2039C<IO::AIO::munmap> functions are called. 2116or C<IO::AIO::munmap> functions are called on it.
2040 2117
2041This calls the C<mmap>(2) function internally. See your system's manual 2118This calls the C<mmap>(2) function internally. See your system's manual
2042page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2119page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2043 2120
2044The C<$length> must be larger than zero and smaller than the actual 2121The C<$length> must be larger than zero and smaller than the actual
2045filesize. 2122filesize.
2046 2123
2047C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2124C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2048C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2125C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2049 2126
2050C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2127C<$flags> can be a combination of
2051C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2128C<IO::AIO::MAP_SHARED> or
2052not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2129C<IO::AIO::MAP_PRIVATE>,
2130or a number of system-specific flags (when not available, the are C<0>):
2053(which is set to C<MAP_ANON> if your system only provides this 2131C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2054constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2132C<IO::AIO::MAP_LOCKED>,
2055C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2133C<IO::AIO::MAP_NORESERVE>,
2134C<IO::AIO::MAP_POPULATE>,
2056C<IO::AIO::MAP_NONBLOCK> 2135C<IO::AIO::MAP_NONBLOCK>,
2136C<IO::AIO::MAP_FIXED>,
2137C<IO::AIO::MAP_GROWSDOWN>,
2138C<IO::AIO::MAP_32BIT>,
2139C<IO::AIO::MAP_HUGETLB> or
2140C<IO::AIO::MAP_STACK>.
2057 2141
2058If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2142If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2059 2143
2060C<$offset> is the offset from the start of the file - it generally must be 2144C<$offset> is the offset from the start of the file - it generally must be
2061a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2145a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2074 my $fast_md5 = md5 $data; 2158 my $fast_md5 = md5 $data;
2075 2159
2076=item IO::AIO::munmap $scalar 2160=item IO::AIO::munmap $scalar
2077 2161
2078Removes a previous mmap and undefines the C<$scalar>. 2162Removes a previous mmap and undefines the C<$scalar>.
2163
2164=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2165
2166Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2167been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2168C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2169
2170Returns true if successful, and false otherwise. If the underlying mmapped
2171region has changed address, then the true value has the numerical value
2172C<1>, otherwise it has the numerical value C<0>:
2173
2174 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2175 or die "mremap: $!";
2176
2177 if ($success*1) {
2178 warn "scalar has chanegd address in memory\n";
2179 }
2180
2181C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2182implemented, but not supported and might go away in a future version.
2183
2184On systems where this call is not supported or is not emulated, this call
2185returns falls and sets C<$!> to C<ENOSYS>.
2079 2186
2080=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2187=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2081 2188
2082Calls the C<munlock> function, undoing the effects of a previous 2189Calls the C<munlock> function, undoing the effects of a previous
2083C<aio_mlock> call (see its description for details). 2190C<aio_mlock> call (see its description for details).
… …
2104 2211
2105See the C<splice(2)> manpage for details. 2212See the C<splice(2)> manpage for details.
2106 2213
2107=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2214=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2108 2215
2109Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2216Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2110description for C<IO::AIO::splice> above for details. 2217description for C<IO::AIO::splice> above for details.
2218
2219=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2220
2221Attempts to query or change the pipe buffer size. Obviously works only
2222on pipes, and currently works only on GNU/Linux systems, and fails with
2223C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2224size on other systems, drop me a note.
2225
2226=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2227
2228This is a direct interface to the Linux L<pipe2(2)> system call. If
2229C<$flags> is missing or C<0>, then this should be the same as a call to
2230perl's built-in C<pipe> function and create a new pipe, and works on
2231systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2232(..., 4096, O_BINARY)>.
2233
2234If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2235the given flags (Linux 2.6.27, glibc 2.9).
2236
2237On success, the read and write file handles are returned.
2238
2239On error, nothing will be returned. If the pipe2 syscall is missing and
2240C<$flags> is non-zero, fails with C<ENOSYS>.
2241
2242Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2243time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2244C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2245
2246Example: create a pipe race-free w.r.t. threads and fork:
2247
2248 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2249 or die "pipe2: $!\n";
2250
2251=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2252
2253This is a direct interface to the Linux L<eventfd(2)> system call. The
2254(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2255
2256On success, the new eventfd filehandle is returned, otherwise returns
2257C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2258
2259Please refer to L<eventfd(2)> for more info on this call.
2260
2261The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2262C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2263
2264Example: create a new eventfd filehandle:
2265
2266 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2267 or die "eventfd: $!\n";
2268
2269=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2270
2271This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2272(unhelpful) default for C<$flags> is C<0>.
2273
2274On success, the new timerfd filehandle is returned, otherwise returns
2275C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2276
2277Please refer to L<timerfd_create(2)> for more info on this call.
2278
2279The following C<$clockid> values are
2280available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2281C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2282C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2283C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2284
2285The following C<$flags> values are available (Linux
22862.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2287
2288Example: create a new timerfd and set it to one-second repeated alarms,
2289then wait for two alarms:
2290
2291 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2292 or die "timerfd_create: $!\n";
2293
2294 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2295 or die "timerfd_settime: $!\n";
2296
2297 for (1..2) {
2298 8 == sysread $fh, my $buf, 8
2299 or die "timerfd read failure\n";
2300
2301 printf "number of expirations (likely 1): %d\n",
2302 unpack "Q", $buf;
2303 }
2304
2305=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2306
2307This is a direct interface to the Linux L<timerfd_settime(2)> system
2308call. Please refer to its manpage for more info on this call.
2309
2310The new itimerspec is specified using two (possibly fractional) second
2311values, C<$new_interval> and C<$new_value>).
2312
2313On success, the current interval and value are returned (as per
2314C<timerfd_gettime>). On failure, the empty list is returned.
2315
2316The following C<$flags> values are
2317available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2318C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2319
2320See C<IO::AIO::timerfd_create> for a full example.
2321
2322=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2323
2324This is a direct interface to the Linux L<timerfd_gettime(2)> system
2325call. Please refer to its manpage for more info on this call.
2326
2327On success, returns the current values of interval and value for the given
2328timerfd (as potentially fractional second values). On failure, the empty
2329list is returned.
2111 2330
2112=back 2331=back
2113 2332
2114=cut 2333=cut
2115 2334
… …
2181the process will result in undefined behaviour. Calling it at any time 2400the process will result in undefined behaviour. Calling it at any time
2182will also result in any undefined (by POSIX) behaviour. 2401will also result in any undefined (by POSIX) behaviour.
2183 2402
2184=back 2403=back
2185 2404
2405=head2 LINUX-SPECIFIC CALLS
2406
2407When a call is documented as "linux-specific" then this means it
2408originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2409availability and compatibility of such calls regardless of the platform
2410it is compiled on, so platforms such as FreeBSD which often implement
2411these calls will work. When in doubt, call them and see if they fail wth
2412C<ENOSYS>.
2413
2186=head2 MEMORY USAGE 2414=head2 MEMORY USAGE
2187 2415
2188Per-request usage: 2416Per-request usage:
2189 2417
2190Each aio request uses - depending on your architecture - around 100-200 2418Each aio request uses - depending on your architecture - around 100-200
… …
2202temporary buffers, and each thread requires a stack and other data 2430temporary buffers, and each thread requires a stack and other data
2203structures (usually around 16k-128k, depending on the OS). 2431structures (usually around 16k-128k, depending on the OS).
2204 2432
2205=head1 KNOWN BUGS 2433=head1 KNOWN BUGS
2206 2434
2207Known bugs will be fixed in the next release. 2435Known bugs will be fixed in the next release :)
2436
2437=head1 KNOWN ISSUES
2438
2439Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2440or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2441non-created hash slots or other scalars I didn't think of. It's best to
2442avoid such and either use scalar variables or making sure that the scalar
2443exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2444
2445I am not sure anything can be done about this, so this is considered a
2446known issue, rather than a bug.
2208 2447
2209=head1 SEE ALSO 2448=head1 SEE ALSO
2210 2449
2211L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2450L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2212more natural syntax. 2451more natural syntax.

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