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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 1.301 by root, Mon Mar 18 23:52:09 2019 UTC

1=head1 NAME 1=head1 NAME
2 2
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous/Advanced Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
… …
58not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
59files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
60aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
61using threads anyway. 61using threads anyway.
62 62
63In addition to asynchronous I/O, this module also exports some rather
64arcane interfaces, such as C<madvise> or linux's C<splice> system call,
65which is why the C<A> in C<AIO> can also mean I<advanced>.
66
63Although the module will work in the presence of other (Perl-) threads, 67Although the module will work in the presence of other (Perl-) threads,
64it is currently not reentrant in any way, so use appropriate locking 68it is currently not reentrant in any way, so use appropriate locking
65yourself, always call C<poll_cb> from within the same thread, or never 69yourself, always call C<poll_cb> from within the same thread, or never
66call C<poll_cb> (or other C<aio_> functions) recursively. 70call C<poll_cb> (or other C<aio_> functions) recursively.
67 71
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 = 4.71;
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
… …
795=item aio_rename $srcpath, $dstpath, $callback->($status) 734=item aio_rename $srcpath, $dstpath, $callback->($status)
796 735
797Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 736Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
798rename(2) and call the callback with the result code. 737rename(2) and call the callback with the result code.
799 738
739On systems that support the AIO::WD working directory abstraction
740natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
741of failing, C<rename> is called on the absolute path of C<$wd>.
742
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
800 759
801=item aio_mkdir $pathname, $mode, $callback->($status) 760=item aio_mkdir $pathname, $mode, $callback->($status)
802 761
803Asynchronously mkdir (create) a directory and call the callback with 762Asynchronously mkdir (create) a directory and call the callback with
804the 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
… …
808=item aio_rmdir $pathname, $callback->($status) 767=item aio_rmdir $pathname, $callback->($status)
809 768
810Asynchronously rmdir (delete) a directory and call the callback with the 769Asynchronously rmdir (delete) a directory and call the callback with the
811result code. 770result code.
812 771
772On systems that support the AIO::WD working directory abstraction
773natively, the case C<[$wd, "."]> is specialcased - instead of failing,
774C<rmdir> is called on the absolute path of C<$wd>.
775
813 776
814=item aio_readdir $pathname, $callback->($entries) 777=item aio_readdir $pathname, $callback->($entries)
815 778
816Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 779Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
817directory (i.e. opendir + readdir + closedir). The entries will not be 780directory (i.e. opendir + readdir + closedir). The entries will not be
… …
832 795
833=over 4 796=over 4
834 797
835=item IO::AIO::READDIR_DENTS 798=item IO::AIO::READDIR_DENTS
836 799
837When this flag is off, then the callback gets an arrayref consisting of 800Normally the callback gets an arrayref consisting of names only (as
838names 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
839C<[$name, $type, $inode]> arrayrefs, each describing a single directory 802arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
840entry in more detail. 803single directory entry in more detail:
841 804
842C<$name> is the name of the entry. 805C<$name> is the name of the entry.
843 806
844C<$type> is one of the C<IO::AIO::DT_xxx> constants: 807C<$type> is one of the C<IO::AIO::DT_xxx> constants:
845 808
846C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 809C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
847C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 810C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
848C<IO::AIO::DT_WHT>. 811C<IO::AIO::DT_WHT>.
849 812
850C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 813C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
851know, you have to run stat yourself. Also, for speed reasons, the C<$type> 814to know, you have to run stat yourself. Also, for speed/memory reasons,
852scalars are read-only: you can not modify them. 815the C<$type> scalars are read-only: you must not modify them.
853 816
854C<$inode> is the inode number (which might not be exact on systems with 64 817C<$inode> is the inode number (which might not be exact on systems with 64
855bit inode numbers and 32 bit perls). This field has unspecified content on 818bit inode numbers and 32 bit perls). This field has unspecified content on
856systems that do not deliver the inode information. 819systems that do not deliver the inode information.
857 820
… …
868short names are tried first. 831short names are tried first.
869 832
870=item IO::AIO::READDIR_STAT_ORDER 833=item IO::AIO::READDIR_STAT_ORDER
871 834
872When this flag is set, then the names will be returned in an order 835When this flag is set, then the names will be returned in an order
873suitable for stat()'ing each one. That is, when you plan to stat() 836suitable for stat()'ing each one. That is, when you plan to stat() most or
874all files in the given directory, then the returned order will likely 837all files in the given directory, then the returned order will likely be
875be fastest. 838faster.
876 839
877If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 840If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
878the likely dirs come first, resulting in a less optimal stat order. 841then the likely dirs come first, resulting in a less optimal stat order
842for stat'ing all entries, but likely a more optimal order for finding
843subdirectories.
879 844
880=item IO::AIO::READDIR_FOUND_UNKNOWN 845=item IO::AIO::READDIR_FOUND_UNKNOWN
881 846
882This flag should not be set when calling C<aio_readdirx>. Instead, it 847This flag should not be set when calling C<aio_readdirx>. Instead, it
883is being set by C<aio_readdirx>, when any of the C<$type>'s found were 848is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
885C<$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.
886 851
887=back 852=back
888 853
889 854
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
890=item aio_load $pathname, $data, $callback->($status) 884=item aio_load $pathname, $data, $callback->($status)
891 885
892This 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
893memory. 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.
894 890
895=cut 891=cut
896 892
897sub aio_load($$;$) { 893sub aio_load($$;$) {
898 my ($path, undef, $cb) = @_; 894 my ($path, undef, $cb) = @_;
… …
918=item aio_copy $srcpath, $dstpath, $callback->($status) 914=item aio_copy $srcpath, $dstpath, $callback->($status)
919 915
920Try 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
921destination) from C<$srcpath> to C<$dstpath> and call the callback with 917destination) from C<$srcpath> to C<$dstpath> and call the callback with
922a 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.
923 921
924This is a composite request that creates the destination file with 922This is a composite request that creates the destination file with
925mode 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
926C<aio_sendfile>, followed by restoring atime, mtime, access mode and 924C<aio_sendfile>, followed by restoring atime, mtime, access mode and
927uid/gid, in that order. 925uid/gid, in that order.
… …
1037Scans a directory (similar to C<aio_readdir>) but additionally tries to 1035Scans a directory (similar to C<aio_readdir>) but additionally tries to
1038efficiently separate the entries of directory C<$path> into two sets of 1036efficiently separate the entries of directory C<$path> into two sets of
1039names, directories you can recurse into (directories), and ones you cannot 1037names, directories you can recurse into (directories), and ones you cannot
1040recurse into (everything else, including symlinks to directories). 1038recurse into (everything else, including symlinks to directories).
1041 1039
1042C<aio_scandir> is a composite request that creates of many sub requests_ 1040C<aio_scandir> is a composite request that generates many sub requests.
1043C<$maxreq> specifies the maximum number of outstanding aio requests that 1041C<$maxreq> specifies the maximum number of outstanding aio requests that
1044this function generates. If it is C<< <= 0 >>, then a suitable default 1042this function generates. If it is C<< <= 0 >>, then a suitable default
1045will be chosen (currently 4). 1043will be chosen (currently 4).
1046 1044
1047On error, the callback is called without arguments, otherwise it receives 1045On error, the callback is called without arguments, otherwise it receives
… …
1111 aioreq_pri $pri; 1109 aioreq_pri $pri;
1112 add $grp aio_stat $wd, sub { 1110 add $grp aio_stat $wd, sub {
1113 return $grp->result () if $_[0]; 1111 return $grp->result () if $_[0];
1114 my $now = time; 1112 my $now = time;
1115 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1113 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1114 my $rdxflags = READDIR_DIRS_FIRST;
1115
1116 if ((stat _)[3] < 2) {
1117 # at least one non-POSIX filesystem exists
1118 # that returns useful DT_type values: btrfs,
1119 # so optimise for this here by requesting dents
1120 $rdxflags |= READDIR_DENTS;
1121 }
1116 1122
1117 # read the directory entries 1123 # read the directory entries
1118 aioreq_pri $pri; 1124 aioreq_pri $pri;
1119 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1125 add $grp aio_readdirx $wd, $rdxflags, sub {
1120 my $entries = shift 1126 my ($entries, $flags) = @_
1121 or return $grp->result (); 1127 or return $grp->result ();
1128
1129 if ($rdxflags & READDIR_DENTS) {
1130 # if we requested type values, see if we can use them directly.
1131
1132 # if there were any DT_UNKNOWN entries then we assume we
1133 # don't know. alternatively, we could assume that if we get
1134 # one DT_DIR, then all directories are indeed marked with
1135 # DT_DIR, but this seems not required for btrfs, and this
1136 # is basically the "btrfs can't get it's act together" code
1137 # branch.
1138 unless ($flags & READDIR_FOUND_UNKNOWN) {
1139 # now we have valid DT_ information for all entries,
1140 # so use it as an optimisation without further stat's.
1141 # they must also all be at the beginning of @$entries
1142 # by now.
1143
1144 my $dirs;
1145
1146 if (@$entries) {
1147 for (0 .. $#$entries) {
1148 if ($entries->[$_][1] != DT_DIR) {
1149 # splice out directories
1150 $dirs = [splice @$entries, 0, $_];
1151 last;
1152 }
1153 }
1154
1155 # if we didn't find any non-dir, then all entries are dirs
1156 unless ($dirs) {
1157 ($dirs, $entries) = ($entries, []);
1158 }
1159 } else {
1160 # directory is empty, so there are no sbdirs
1161 $dirs = [];
1162 }
1163
1164 # either splice'd the directories out or the dir was empty.
1165 # convert dents to filenames
1166 $_ = $_->[0] for @$dirs;
1167 $_ = $_->[0] for @$entries;
1168
1169 return $grp->result ($dirs, $entries);
1170 }
1171
1172 # cannot use, so return to our old ways
1173 # by pretending we only scanned for names.
1174 $_ = $_->[0] for @$entries;
1175 }
1122 1176
1123 # stat the dir another time 1177 # stat the dir another time
1124 aioreq_pri $pri; 1178 aioreq_pri $pri;
1125 add $grp aio_stat $wd, sub { 1179 add $grp aio_stat $wd, sub {
1126 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1180 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1213 }; 1267 };
1214 1268
1215 $grp 1269 $grp
1216} 1270}
1217 1271
1272=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1273
1274=item aio_ioctl $fh, $request, $buf, $callback->($status)
1275
1276These work just like the C<fcntl> and C<ioctl> built-in functions, except
1277they execute asynchronously and pass the return value to the callback.
1278
1279Both calls can be used for a lot of things, some of which make more sense
1280to run asynchronously in their own thread, while some others make less
1281sense. For example, calls that block waiting for external events, such
1282as locking, will also lock down an I/O thread while it is waiting, which
1283can deadlock the whole I/O system. At the same time, there might be no
1284alternative to using a thread to wait.
1285
1286So in general, you should only use these calls for things that do
1287(filesystem) I/O, not for things that wait for other events (network,
1288other processes), although if you are careful and know what you are doing,
1289you still can.
1290
1291The following constants are available (missing ones are, as usual C<0>):
1292
1293C<F_DUPFD_CLOEXEC>,
1294
1295C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1296
1297C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1298
1299C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1300C<FS_IOC_FIEMAP>.
1301
1302C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1303C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1304
1305C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1306C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1307C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1308C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1309C<FS_FL_USER_MODIFIABLE>.
1310
1311C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1312C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1313C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1314C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1315
1218=item aio_sync $callback->($status) 1316=item aio_sync $callback->($status)
1219 1317
1220Asynchronously call sync and call the callback when finished. 1318Asynchronously call sync and call the callback when finished.
1221 1319
1222=item aio_fsync $fh, $callback->($status) 1320=item aio_fsync $fh, $callback->($status)
… …
1290 }; 1388 };
1291 1389
1292 $grp 1390 $grp
1293} 1391}
1294 1392
1295=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1393=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1296 1394
1297This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1395This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1298scalars (see the C<IO::AIO::mmap> function, although it also works on data 1396scalars (see the C<IO::AIO::mmap> function, although it also works on data
1299scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1397scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1300scalar must only be modified in-place while an aio operation is pending on 1398scalar must only be modified in-place while an aio operation is pending on
… …
1302 1400
1303It calls the C<msync> function of your OS, if available, with the memory 1401It calls the C<msync> function of your OS, if available, with the memory
1304area starting at C<$offset> in the string and ending C<$length> bytes 1402area starting at C<$offset> in the string and ending C<$length> bytes
1305later. If C<$length> is negative, counts from the end, and if C<$length> 1403later. If C<$length> is negative, counts from the end, and if C<$length>
1306is C<undef>, then it goes till the end of the string. The flags can be 1404is C<undef>, then it goes till the end of the string. The flags can be
1307a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1405either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1308C<IO::AIO::MS_SYNC>. 1406C<IO::AIO::MS_INVALIDATE>.
1309 1407
1310=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1408=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1311 1409
1312This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1410This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1313scalars. 1411scalars.
… …
1343 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1441 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1344 aio_mlock $data; # mlock in background 1442 aio_mlock $data; # mlock in background
1345 1443
1346=item aio_mlockall $flags, $callback->($status) 1444=item aio_mlockall $flags, $callback->($status)
1347 1445
1348Calls the C<mlockall> function with the given C<$flags> (a combination of 1446Calls the C<mlockall> function with the given C<$flags> (a
1349C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1447combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1448C<IO::AIO::MCL_ONFAULT>).
1350 1449
1351On systems that do not implement C<mlockall>, this function returns C<-1> 1450On systems that do not implement C<mlockall>, this function returns C<-1>
1352and sets errno to C<ENOSYS>. 1451and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1452by the system result in a return value of C<-1> with errno being set to
1453C<EINVAL>.
1353 1454
1354Note that the corresponding C<munlockall> is synchronous and is 1455Note that the corresponding C<munlockall> is synchronous and is
1355documented under L<MISCELLANEOUS FUNCTIONS>. 1456documented under L<MISCELLANEOUS FUNCTIONS>.
1356 1457
1357Example: asynchronously lock all current and future pages into memory. 1458Example: asynchronously lock all current and future pages into memory.
… …
1396C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1497C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1397C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1498C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1398C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1499C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1399C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1500C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1400 1501
1401At the time of this writing (Linux 3.2), this requets is unreliable unless 1502At the time of this writing (Linux 3.2), this request is unreliable unless
1402C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1503C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1403it to return all extents of a range for files with large number of 1504it to return all extents of a range for files with a large number of
1404extents. The code works around all these issues if C<$count> is undef. 1505extents. The code (only) works around all these issues if C<$count> is
1506C<undef>.
1405 1507
1406=item aio_group $callback->(...) 1508=item aio_group $callback->(...)
1407 1509
1408This is a very special aio request: Instead of doing something, it is a 1510This is a very special aio request: Instead of doing something, it is a
1409container for other aio requests, which is useful if you want to bundle 1511container for other aio requests, which is useful if you want to bundle
… …
1493 aio_stat [$etcdir, "passwd"], sub { 1595 aio_stat [$etcdir, "passwd"], sub {
1494 # yay 1596 # yay
1495 }; 1597 };
1496 }; 1598 };
1497 1599
1498That C<aio_wd> is a request and not a normal function shows that creating 1600The 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 1601creating an IO::AIO::WD object is itself a potentially blocking operation,
1500why it is done asynchronously. 1602which is why it is done asynchronously.
1501 1603
1502To stat the directory obtained with C<aio_wd> above, one could write 1604To stat the directory obtained with C<aio_wd> above, one could write
1503either of the following three request calls: 1605either of the following three request calls:
1504 1606
1505 aio_lstat "/etc" , sub { ... # pathname as normal string 1607 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1522There are some caveats: when directories get renamed (or deleted), the 1624There are some caveats: when directories get renamed (or deleted), the
1523pathname string doesn't change, so will point to the new directory (or 1625pathname string doesn't change, so will point to the new directory (or
1524nowhere at all), while the directory fd, if available on the system, 1626nowhere at all), while the directory fd, if available on the system,
1525will still point to the original directory. Most functions accepting a 1627will still point to the original directory. Most functions accepting a
1526pathname will use the directory fd on newer systems, and the string on 1628pathname will use the directory fd on newer systems, and the string on
1527older systems. Some functions (such as realpath) will always rely on the 1629older systems. Some functions (such as C<aio_realpath>) will always rely on
1528string form of the pathname. 1630the string form of the pathname.
1529 1631
1530So this functionality is mainly useful to get some protection against 1632So 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 1633C<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 1634reference, and to speed up doing many operations in the same directory
1533(e.g. when stat'ing all files in a directory). 1635(e.g. when stat'ing all files in a directory).
… …
1548passing C<undef> as working directory component of a pathname fails the 1650passing 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 1651request 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 1652C<aio_wd> callback, as future requests using the value will fail in the
1551expected way. 1653expected way.
1552 1654
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 1655=item IO::AIO::CWD
1557 1656
1558This is a compiletime constant (object) that represents the process 1657This is a compiletime constant (object) that represents the process
1559current working directory. 1658current working directory.
1560 1659
… …
1572 1671
1573 aio_realpath $wd, sub { 1672 aio_realpath $wd, sub {
1574 warn "path is $_[0]\n"; 1673 warn "path is $_[0]\n";
1575 }; 1674 };
1576 1675
1676Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1677sometimes, fall back to using an absolue path.
1577 1678
1578=head2 IO::AIO::REQ CLASS 1679=head2 IO::AIO::REQ CLASS
1579 1680
1580All non-aggregate C<aio_*> functions return an object of this class when 1681All non-aggregate C<aio_*> functions return an object of this class when
1581called in non-void context. 1682called in non-void context.
… …
1742The default value for the limit is C<0>, but note that setting a feeder 1843The default value for the limit is C<0>, but note that setting a feeder
1743automatically bumps it up to C<2>. 1844automatically bumps it up to C<2>.
1744 1845
1745=back 1846=back
1746 1847
1848
1747=head2 SUPPORT FUNCTIONS 1849=head2 SUPPORT FUNCTIONS
1748 1850
1749=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1851=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1750 1852
1751=over 4 1853=over 4
… …
1816Strictly equivalent to: 1918Strictly equivalent to:
1817 1919
1818 IO::AIO::poll_wait, IO::AIO::poll_cb 1920 IO::AIO::poll_wait, IO::AIO::poll_cb
1819 while IO::AIO::nreqs; 1921 while IO::AIO::nreqs;
1820 1922
1923This function can be useful at program aborts, to make sure outstanding
1924I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1925this function on normal exits), or when you are merely using C<IO::AIO>
1926for its more advanced functions, rather than for async I/O, e.g.:
1927
1928 my ($dirs, $nondirs);
1929 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1930 IO::AIO::flush;
1931 # $dirs, $nondirs are now set
1932
1821=item IO::AIO::max_poll_reqs $nreqs 1933=item IO::AIO::max_poll_reqs $nreqs
1822 1934
1823=item IO::AIO::max_poll_time $seconds 1935=item IO::AIO::max_poll_time $seconds
1824 1936
1825These set the maximum number of requests (default C<0>, meaning infinity) 1937These set the maximum number of requests (default C<0>, meaning infinity)
… …
1851 poll => 'r', nice => 1, 1963 poll => 'r', nice => 1,
1852 cb => &IO::AIO::poll_cb); 1964 cb => &IO::AIO::poll_cb);
1853 1965
1854=back 1966=back
1855 1967
1968
1856=head3 CONTROLLING THE NUMBER OF THREADS 1969=head3 CONTROLLING THE NUMBER OF THREADS
1857 1970
1858=over 1971=over
1859 1972
1860=item IO::AIO::min_parallel $nthreads 1973=item IO::AIO::min_parallel $nthreads
… …
1925 2038
1926This is a very bad function to use in interactive programs because it 2039This is a very bad function to use in interactive programs because it
1927blocks, and a bad way to reduce concurrency because it is inexact: Better 2040blocks, and a bad way to reduce concurrency because it is inexact: Better
1928use an C<aio_group> together with a feed callback. 2041use an C<aio_group> together with a feed callback.
1929 2042
1930It's main use is in scripts without an event loop - when you want to stat 2043Its main use is in scripts without an event loop - when you want to stat
1931a lot of files, you can write somehting like this: 2044a lot of files, you can write something like this:
1932 2045
1933 IO::AIO::max_outstanding 32; 2046 IO::AIO::max_outstanding 32;
1934 2047
1935 for my $path (...) { 2048 for my $path (...) {
1936 aio_stat $path , ...; 2049 aio_stat $path , ...;
… …
1947The default value for C<max_outstanding> is very large, so there is no 2060The default value for C<max_outstanding> is very large, so there is no
1948practical limit on the number of outstanding requests. 2061practical limit on the number of outstanding requests.
1949 2062
1950=back 2063=back
1951 2064
2065
1952=head3 STATISTICAL INFORMATION 2066=head3 STATISTICAL INFORMATION
1953 2067
1954=over 2068=over
1955 2069
1956=item IO::AIO::nreqs 2070=item IO::AIO::nreqs
… …
1973Returns the number of requests currently in the pending state (executed, 2087Returns the number of requests currently in the pending state (executed,
1974but not yet processed by poll_cb). 2088but not yet processed by poll_cb).
1975 2089
1976=back 2090=back
1977 2091
2092
2093=head3 SUBSECOND STAT TIME ACCESS
2094
2095Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2096generally find access/modification and change times with subsecond time
2097accuracy of the system supports it, but perl's built-in functions only
2098return the integer part.
2099
2100The following functions return the timestamps of the most recent
2101stat with subsecond precision on most systems and work both after
2102C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2103value is only meaningful after a successful C<stat>/C<lstat> call, or
2104during/after a successful C<aio_stat>/C<aio_lstat> callback.
2105
2106This is similar to the L<Time::HiRes> C<stat> functions, but can return
2107full resolution without rounding and work with standard perl C<stat>,
2108alleviating the need to call the special C<Time::HiRes> functions, which
2109do not act like their perl counterparts.
2110
2111On operating systems or file systems where subsecond time resolution is
2112not supported or could not be detected, a fractional part of C<0> is
2113returned, so it is always safe to call these functions.
2114
2115=over 4
2116
2117=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2118
2119Return the access, modication, change or birth time, respectively,
2120including fractional part. Due to the limited precision of floating point,
2121the accuracy on most platforms is only a bit better than milliseconds
2122for times around now - see the I<nsec> function family, below, for full
2123accuracy.
2124
2125File birth time is only available when the OS and perl support it (on
2126FreeBSD and NetBSD at the time of this writing, although support is
2127adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
2128it). On systems where it isn't available, C<0> is currently returned, but
2129this might change to C<undef> in a future version.
2130
2131=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2132
2133Returns access, modification, change and birth time all in one go, and
2134maybe more times in the future version.
2135
2136=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2137
2138Return the fractional access, modifcation, change or birth time, in nanoseconds,
2139as an integer in the range C<0> to C<999999999>.
2140
2141Note that no accessors are provided for access, modification and
2142change times - you need to get those from C<stat _> if required (C<int
2143IO::AIO::st_atime> and so on will I<not> generally give you the correct
2144value).
2145
2146=item $seconds = IO::AIO::st_btimesec
2147
2148The (integral) seconds part of the file birth time, if available.
2149
2150=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2151
2152Like the functions above, but returns all four times in one go (and maybe
2153more in future versions).
2154
2155=item $counter = IO::AIO::st_gen
2156
2157Returns the generation counter (in practice this is just a random number)
2158of the file. This is only available on platforms which have this member in
2159their C<struct stat> (most BSDs at the time of this writing) and generally
2160only to the root usert. If unsupported, C<0> is returned, but this might
2161change to C<undef> in a future version.
2162
2163=back
2164
2165Example: print the high resolution modification time of F</etc>, using
2166C<stat>, and C<IO::AIO::aio_stat>.
2167
2168 if (stat "/etc") {
2169 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2170 }
2171
2172 IO::AIO::aio_stat "/etc", sub {
2173 $_[0]
2174 and return;
2175
2176 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2177 };
2178
2179 IO::AIO::flush;
2180
2181Output of the awbove on my system, showing reduced and full accuracy:
2182
2183 stat(/etc) mtime: 1534043702.020808
2184 aio_stat(/etc) mtime: 1534043702.020807792
2185
2186
1978=head3 MISCELLANEOUS FUNCTIONS 2187=head3 MISCELLANEOUS FUNCTIONS
1979 2188
1980IO::AIO implements some functions that might be useful, but are not 2189IO::AIO implements some functions that are useful when you want to use
1981asynchronous. 2190some "Advanced I/O" function not available to in Perl, without going the
2191"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2192counterpart.
1982 2193
1983=over 4 2194=over 4
2195
2196=item $numfd = IO::AIO::get_fdlimit
2197
2198This function is I<EXPERIMENTAL> and subject to change.
2199
2200Tries to find the current file descriptor limit and returns it, or
2201C<undef> and sets C<$!> in case of an error. The limit is one larger than
2202the highest valid file descriptor number.
2203
2204=item IO::AIO::min_fdlimit [$numfd]
2205
2206This function is I<EXPERIMENTAL> and subject to change.
2207
2208Try to increase the current file descriptor limit(s) to at least C<$numfd>
2209by changing the soft or hard file descriptor resource limit. If C<$numfd>
2210is missing, it will try to set a very high limit, although this is not
2211recommended when you know the actual minimum that you require.
2212
2213If the limit cannot be raised enough, the function makes a best-effort
2214attempt to increase the limit as much as possible, using various
2215tricks, while still failing. You can query the resulting limit using
2216C<IO::AIO::get_fdlimit>.
2217
2218If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2219true.
1984 2220
1985=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2221=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1986 2222
1987Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2223Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1988but is blocking (this makes most sense if you know the input data is 2224but is blocking (this makes most sense if you know the input data is
… …
2005=item IO::AIO::madvise $scalar, $offset, $len, $advice 2241=item IO::AIO::madvise $scalar, $offset, $len, $advice
2006 2242
2007Simply calls the C<posix_madvise> function (see its 2243Simply calls the C<posix_madvise> function (see its
2008manpage for details). The following advice constants are 2244manpage for details). The following advice constants are
2009available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2245available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2010C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2246C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2247C<IO::AIO::MADV_DONTNEED>.
2248
2249If C<$offset> is negative, counts from the end. If C<$length> is negative,
2250the remaining length of the C<$scalar> is used. If possible, C<$length>
2251will be reduced to fit into the C<$scalar>.
2011 2252
2012On systems that do not implement C<posix_madvise>, this function returns 2253On systems that do not implement C<posix_madvise>, this function returns
2013ENOSYS, otherwise the return value of C<posix_madvise>. 2254ENOSYS, otherwise the return value of C<posix_madvise>.
2014 2255
2015=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2256=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2017Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2258Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2018$scalar (see its manpage for details). The following protect 2259$scalar (see its manpage for details). The following protect
2019constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2260constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2020C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2261C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2021 2262
2263If C<$offset> is negative, counts from the end. If C<$length> is negative,
2264the remaining length of the C<$scalar> is used. If possible, C<$length>
2265will be reduced to fit into the C<$scalar>.
2266
2022On systems that do not implement C<mprotect>, this function returns 2267On systems that do not implement C<mprotect>, this function returns
2023ENOSYS, otherwise the return value of C<mprotect>. 2268ENOSYS, otherwise the return value of C<mprotect>.
2024 2269
2025=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2270=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2026 2271
2027Memory-maps a file (or anonymous memory range) and attaches it to the 2272Memory-maps a file (or anonymous memory range) and attaches it to the
2028given C<$scalar>, which will act like a string scalar. Returns true on 2273given C<$scalar>, which will act like a string scalar. Returns true on
2029success, and false otherwise. 2274success, and false otherwise.
2030 2275
2276The scalar must exist, but its contents do not matter - this means you
2277cannot use a nonexistant array or hash element. When in doubt, C<undef>
2278the scalar first.
2279
2031The only operations allowed on the scalar are C<substr>/C<vec> that don't 2280The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2032change the string length, and most read-only operations such as copying it 2281which don't change the string length, and most read-only operations such
2033or searching it with regexes and so on. 2282as copying it or searching it with regexes and so on.
2034 2283
2035Anything else is unsafe and will, at best, result in memory leaks. 2284Anything else is unsafe and will, at best, result in memory leaks.
2036 2285
2037The memory map associated with the C<$scalar> is automatically removed 2286The memory map associated with the C<$scalar> is automatically removed
2038when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2287when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2039C<IO::AIO::munmap> functions are called. 2288or C<IO::AIO::munmap> functions are called on it.
2040 2289
2041This calls the C<mmap>(2) function internally. See your system's manual 2290This calls the C<mmap>(2) function internally. See your system's manual
2042page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2291page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2043 2292
2044The C<$length> must be larger than zero and smaller than the actual 2293The C<$length> must be larger than zero and smaller than the actual
2045filesize. 2294filesize.
2046 2295
2047C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2296C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2048C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2297C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2049 2298
2050C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2299C<$flags> can be a combination of
2051C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2300C<IO::AIO::MAP_SHARED> or
2052not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2301C<IO::AIO::MAP_PRIVATE>,
2302or a number of system-specific flags (when not available, the are C<0>):
2053(which is set to C<MAP_ANON> if your system only provides this 2303C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2054constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2304C<IO::AIO::MAP_LOCKED>,
2055C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2305C<IO::AIO::MAP_NORESERVE>,
2306C<IO::AIO::MAP_POPULATE>,
2056C<IO::AIO::MAP_NONBLOCK> 2307C<IO::AIO::MAP_NONBLOCK>,
2308C<IO::AIO::MAP_FIXED>,
2309C<IO::AIO::MAP_GROWSDOWN>,
2310C<IO::AIO::MAP_32BIT>,
2311C<IO::AIO::MAP_HUGETLB> or
2312C<IO::AIO::MAP_STACK>.
2057 2313
2058If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2314If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2059 2315
2060C<$offset> is the offset from the start of the file - it generally must be 2316C<$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>. 2317a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2074 my $fast_md5 = md5 $data; 2330 my $fast_md5 = md5 $data;
2075 2331
2076=item IO::AIO::munmap $scalar 2332=item IO::AIO::munmap $scalar
2077 2333
2078Removes a previous mmap and undefines the C<$scalar>. 2334Removes a previous mmap and undefines the C<$scalar>.
2335
2336=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2337
2338Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2339been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2340C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2341
2342Returns true if successful, and false otherwise. If the underlying mmapped
2343region has changed address, then the true value has the numerical value
2344C<1>, otherwise it has the numerical value C<0>:
2345
2346 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2347 or die "mremap: $!";
2348
2349 if ($success*1) {
2350 warn "scalar has chanegd address in memory\n";
2351 }
2352
2353C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2354implemented, but not supported and might go away in a future version.
2355
2356On systems where this call is not supported or is not emulated, this call
2357returns falls and sets C<$!> to C<ENOSYS>.
2358
2359=item IO::AIO::mlockall $flags
2360
2361Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2362but is blocking.
2079 2363
2080=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2364=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2081 2365
2082Calls the C<munlock> function, undoing the effects of a previous 2366Calls the C<munlock> function, undoing the effects of a previous
2083C<aio_mlock> call (see its description for details). 2367C<aio_mlock> call (see its description for details).
… …
2104 2388
2105See the C<splice(2)> manpage for details. 2389See the C<splice(2)> manpage for details.
2106 2390
2107=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2391=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2108 2392
2109Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2393Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2110description for C<IO::AIO::splice> above for details. 2394description for C<IO::AIO::splice> above for details.
2395
2396=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2397
2398Attempts to query or change the pipe buffer size. Obviously works only
2399on pipes, and currently works only on GNU/Linux systems, and fails with
2400C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2401size on other systems, drop me a note.
2402
2403=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2404
2405This is a direct interface to the Linux L<pipe2(2)> system call. If
2406C<$flags> is missing or C<0>, then this should be the same as a call to
2407perl's built-in C<pipe> function and create a new pipe, and works on
2408systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2409(..., 4096, O_BINARY)>.
2410
2411If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2412the given flags (Linux 2.6.27, glibc 2.9).
2413
2414On success, the read and write file handles are returned.
2415
2416On error, nothing will be returned. If the pipe2 syscall is missing and
2417C<$flags> is non-zero, fails with C<ENOSYS>.
2418
2419Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2420time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2421C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2422
2423Example: create a pipe race-free w.r.t. threads and fork:
2424
2425 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2426 or die "pipe2: $!\n";
2427
2428=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2429
2430This is a direct interface to the Linux L<eventfd(2)> system call. The
2431(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2432
2433On success, the new eventfd filehandle is returned, otherwise returns
2434C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2435
2436Please refer to L<eventfd(2)> for more info on this call.
2437
2438The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2439C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2440
2441Example: create a new eventfd filehandle:
2442
2443 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2444 or die "eventfd: $!\n";
2445
2446=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2447
2448This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2449(unhelpful) default for C<$flags> is C<0>.
2450
2451On success, the new timerfd filehandle is returned, otherwise returns
2452C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2453
2454Please refer to L<timerfd_create(2)> for more info on this call.
2455
2456The following C<$clockid> values are
2457available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2458C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2459C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2460C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2461
2462The following C<$flags> values are available (Linux
24632.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2464
2465Example: create a new timerfd and set it to one-second repeated alarms,
2466then wait for two alarms:
2467
2468 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2469 or die "timerfd_create: $!\n";
2470
2471 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2472 or die "timerfd_settime: $!\n";
2473
2474 for (1..2) {
2475 8 == sysread $fh, my $buf, 8
2476 or die "timerfd read failure\n";
2477
2478 printf "number of expirations (likely 1): %d\n",
2479 unpack "Q", $buf;
2480 }
2481
2482=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2483
2484This is a direct interface to the Linux L<timerfd_settime(2)> system
2485call. Please refer to its manpage for more info on this call.
2486
2487The new itimerspec is specified using two (possibly fractional) second
2488values, C<$new_interval> and C<$new_value>).
2489
2490On success, the current interval and value are returned (as per
2491C<timerfd_gettime>). On failure, the empty list is returned.
2492
2493The following C<$flags> values are
2494available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2495C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2496
2497See C<IO::AIO::timerfd_create> for a full example.
2498
2499=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2500
2501This is a direct interface to the Linux L<timerfd_gettime(2)> system
2502call. Please refer to its manpage for more info on this call.
2503
2504On success, returns the current values of interval and value for the given
2505timerfd (as potentially fractional second values). On failure, the empty
2506list is returned.
2111 2507
2112=back 2508=back
2113 2509
2114=cut 2510=cut
2115 2511
… …
2181the process will result in undefined behaviour. Calling it at any time 2577the process will result in undefined behaviour. Calling it at any time
2182will also result in any undefined (by POSIX) behaviour. 2578will also result in any undefined (by POSIX) behaviour.
2183 2579
2184=back 2580=back
2185 2581
2582=head2 LINUX-SPECIFIC CALLS
2583
2584When a call is documented as "linux-specific" then this means it
2585originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2586availability and compatibility of such calls regardless of the platform
2587it is compiled on, so platforms such as FreeBSD which often implement
2588these calls will work. When in doubt, call them and see if they fail wth
2589C<ENOSYS>.
2590
2186=head2 MEMORY USAGE 2591=head2 MEMORY USAGE
2187 2592
2188Per-request usage: 2593Per-request usage:
2189 2594
2190Each aio request uses - depending on your architecture - around 100-200 2595Each aio request uses - depending on your architecture - around 100-200
… …
2202temporary buffers, and each thread requires a stack and other data 2607temporary buffers, and each thread requires a stack and other data
2203structures (usually around 16k-128k, depending on the OS). 2608structures (usually around 16k-128k, depending on the OS).
2204 2609
2205=head1 KNOWN BUGS 2610=head1 KNOWN BUGS
2206 2611
2207Known bugs will be fixed in the next release. 2612Known bugs will be fixed in the next release :)
2613
2614=head1 KNOWN ISSUES
2615
2616Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2617or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2618non-created hash slots or other scalars I didn't think of. It's best to
2619avoid such and either use scalar variables or making sure that the scalar
2620exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2621
2622I am not sure anything can be done about this, so this is considered a
2623known issue, rather than a bug.
2208 2624
2209=head1 SEE ALSO 2625=head1 SEE ALSO
2210 2626
2211L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2627L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2212more natural syntax. 2628more natural syntax.

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