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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.241 by root, Fri Dec 28 07:33:41 2012 UTC vs.
Revision 1.304 by root, Wed Apr 3 03:11:45 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 = 4.72;
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 IO::AIO::reinit
284
285 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
286 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
276 287
277 IO::AIO::sendfile $ofh, $ifh, $offset, $count 288 IO::AIO::sendfile $ofh, $ifh, $offset, $count
278 IO::AIO::fadvise $fh, $offset, $len, $advice 289 IO::AIO::fadvise $fh, $offset, $len, $advice
290
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 291 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar 292 IO::AIO::munmap $scalar
293 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
281 IO::AIO::madvise $scalar, $offset, $length, $advice 294 IO::AIO::madvise $scalar, $offset, $length, $advice
282 IO::AIO::mprotect $scalar, $offset, $length, $protect 295 IO::AIO::mprotect $scalar, $offset, $length, $protect
283 IO::AIO::munlock $scalar, $offset = 0, $length = undef 296 IO::AIO::munlock $scalar, $offset = 0, $length = undef
284 IO::AIO::munlockall 297 IO::AIO::munlockall
298
299 # stat extensions
300 $counter = IO::AIO::st_gen
301 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
302 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
303 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
304 $seconds = IO::AIO::st_btimesec
305 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
306
307 # very much unportable syscalls
308 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
309 IO::AIO::tee $r_fh, $w_fh, $length, $flags
310 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
311 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
312 $fh = IO::AIO::memfd_create $pathname[, $flags]
313 $fh = IO::AIO::eventfd [$initval, [$flags]]
314 $fh = IO::AIO::timerfd_create $clockid[, $flags]
315 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
316 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
285 317
286=head2 API NOTES 318=head2 API NOTES
287 319
288All the C<aio_*> calls are more or less thin wrappers around the syscall 320All the C<aio_*> calls are more or less thin wrappers around the syscall
289with the same name (sans C<aio_>). The arguments are similar or identical, 321with the same name (sans C<aio_>). The arguments are similar or identical,
… …
395following POSIX and non-POSIX constants are available (missing ones on 427following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 428your system are, as usual, C<0>):
397 429
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 430C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
399C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 431C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
400C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 432C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
401 433
402 434
403=item aio_close $fh, $callback->($status) 435=item aio_close $fh, $callback->($status)
404 436
405Asynchronously close a file and call the callback with the result 437Asynchronously close a file and call the callback with the result
… …
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 472=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 473
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 474=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 475
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 476Reads or writes C<$length> bytes from or to the specified C<$fh> and
445C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 477C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
446and calls the callback without the actual number of bytes read (or -1 on 478calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 479error, just like the syscall).
448 480
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 481C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 482offset plus the actual number of bytes read.
451 483
… …
509As native sendfile syscalls (as practically any non-POSIX interface hacked 541As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 542together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 543on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 544in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 545so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 546fewer bytes than expected might have been transferred.
515 547
516 548
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 549=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 550
519C<aio_readahead> populates the page cache with data from a file so that 551C<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 555whole 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 556and 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 557(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. 558file. The current file offset of the file is left unchanged.
527 559
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 560If 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. 561be emulated by simply reading the data, which would have a similar effect.
530 562
531 563
532=item aio_stat $fh_or_path, $callback->($status) 564=item aio_stat $fh_or_path, $callback->($status)
533 565
534=item aio_lstat $fh, $callback->($status) 566=item aio_lstat $fh, $callback->($status)
535 567
536Works like perl's C<stat> or C<lstat> in void context. The callback will 568Works almost exactly like perl's C<stat> or C<lstat> in void context. The
537be called after the stat and the results will be available using C<stat _> 569callback will be called after the stat and the results will be available
538or C<-s _> etc... 570using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
571and C<-T>).
539 572
540The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 573The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
541for an explanation. 574for an explanation.
542 575
543Currently, the stats are always 64-bit-stats, i.e. instead of returning an 576Currently, the stats are always 64-bit-stats, i.e. instead of returning an
… …
550behaviour). 583behaviour).
551 584
552C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 585C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
553C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, 586C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
554C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. 587C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
588
589To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
590ACCESS>.
555 591
556Example: Print the length of F</etc/passwd>: 592Example: Print the length of F</etc/passwd>:
557 593
558 aio_stat "/etc/passwd", sub { 594 aio_stat "/etc/passwd", sub {
559 $_[0] and die "stat failed: $!"; 595 $_[0] and die "stat failed: $!";
… …
603 namemax => 255, 639 namemax => 255,
604 frsize => 1024, 640 frsize => 1024,
605 fsid => 1810 641 fsid => 1810
606 } 642 }
607 643
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) 644=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
691 645
692Works like perl's C<utime> function (including the special case of $atime 646Works like perl's C<utime> function (including the special case of $atime
693and $mtime being undef). Fractional times are supported if the underlying 647and $mtime being undef). Fractional times are supported if the underlying
694syscalls support them. 648syscalls support them.
695 649
696When called with a pathname, uses utimes(2) if available, otherwise 650When 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, 651otherwise utime(2). If called on a file descriptor, uses futimens(2)
698otherwise returns ENOSYS, so this is not portable. 652or futimes(2) if available, otherwise returns ENOSYS, so this is not
653portable.
699 654
700Examples: 655Examples:
701 656
702 # set atime and mtime to current time (basically touch(1)): 657 # set atime and mtime to current time (basically touch(1)):
703 aio_utime "path", undef, undef; 658 aio_utime "path", undef, undef;
… …
723Works like truncate(2) or ftruncate(2). 678Works like truncate(2) or ftruncate(2).
724 679
725 680
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 681=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727 682
728Allocates or freed disk space according to the C<$mode> argument. See the 683Allocates or frees disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details. 684linux C<fallocate> documentation for details.
730 685
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 686C<$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 | 687space, 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. 688to deallocate a file range.
689
690IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
691(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
692C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
693to unshare shared blocks (see your L<fallocate(2)> manpage).
734 694
735The file system block size used by C<fallocate> is presumably the 695The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>. 696C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
697can dictate other limitations.
737 698
738If C<fallocate> isn't available or cannot be emulated (currently no 699If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 700emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740 701
741 702
… …
800On systems that support the AIO::WD working directory abstraction 761On systems that support the AIO::WD working directory abstraction
801natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 762natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
802of failing, C<rename> is called on the absolute path of C<$wd>. 763of failing, C<rename> is called on the absolute path of C<$wd>.
803 764
804 765
766=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
767
768Basically a version of C<aio_rename> with an additional C<$flags>
769argument. Calling this with C<$flags=0> is the same as calling
770C<aio_rename>.
771
772Non-zero flags are currently only supported on GNU/Linux systems that
773support renameat2. Other systems fail with C<ENOSYS> in this case.
774
775The following constants are available (missing ones are, as usual C<0>),
776see renameat2(2) for details:
777
778C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
779and C<IO::AIO::RENAME_WHITEOUT>.
780
781
805=item aio_mkdir $pathname, $mode, $callback->($status) 782=item aio_mkdir $pathname, $mode, $callback->($status)
806 783
807Asynchronously mkdir (create) a directory and call the callback with 784Asynchronously mkdir (create) a directory and call the callback with
808the result code. C<$mode> will be modified by the umask at the time the 785the result code. C<$mode> will be modified by the umask at the time the
809request is executed, so do not change your umask. 786request is executed, so do not change your umask.
… …
840 817
841=over 4 818=over 4
842 819
843=item IO::AIO::READDIR_DENTS 820=item IO::AIO::READDIR_DENTS
844 821
845When this flag is off, then the callback gets an arrayref consisting of 822Normally the callback gets an arrayref consisting of names only (as
846names only (as with C<aio_readdir>), otherwise it gets an arrayref with 823with C<aio_readdir>). If this flag is set, then the callback gets an
847C<[$name, $type, $inode]> arrayrefs, each describing a single directory 824arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
848entry in more detail. 825single directory entry in more detail:
849 826
850C<$name> is the name of the entry. 827C<$name> is the name of the entry.
851 828
852C<$type> is one of the C<IO::AIO::DT_xxx> constants: 829C<$type> is one of the C<IO::AIO::DT_xxx> constants:
853 830
854C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 831C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
855C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 832C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
856C<IO::AIO::DT_WHT>. 833C<IO::AIO::DT_WHT>.
857 834
858C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 835C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
859know, you have to run stat yourself. Also, for speed reasons, the C<$type> 836to know, you have to run stat yourself. Also, for speed/memory reasons,
860scalars are read-only: you can not modify them. 837the C<$type> scalars are read-only: you must not modify them.
861 838
862C<$inode> is the inode number (which might not be exact on systems with 64 839C<$inode> is the inode number (which might not be exact on systems with 64
863bit inode numbers and 32 bit perls). This field has unspecified content on 840bit inode numbers and 32 bit perls). This field has unspecified content on
864systems that do not deliver the inode information. 841systems that do not deliver the inode information.
865 842
… …
876short names are tried first. 853short names are tried first.
877 854
878=item IO::AIO::READDIR_STAT_ORDER 855=item IO::AIO::READDIR_STAT_ORDER
879 856
880When this flag is set, then the names will be returned in an order 857When this flag is set, then the names will be returned in an order
881suitable for stat()'ing each one. That is, when you plan to stat() 858suitable for stat()'ing each one. That is, when you plan to stat() most or
882all files in the given directory, then the returned order will likely 859all files in the given directory, then the returned order will likely be
883be fastest. 860faster.
884 861
885If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 862If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
886the likely dirs come first, resulting in a less optimal stat order. 863then the likely dirs come first, resulting in a less optimal stat order
864for stat'ing all entries, but likely a more optimal order for finding
865subdirectories.
887 866
888=item IO::AIO::READDIR_FOUND_UNKNOWN 867=item IO::AIO::READDIR_FOUND_UNKNOWN
889 868
890This flag should not be set when calling C<aio_readdirx>. Instead, it 869This flag should not be set when calling C<aio_readdirx>. Instead, it
891is being set by C<aio_readdirx>, when any of the C<$type>'s found were 870is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
893C<$type>'s are known, which can be used to speed up some algorithms. 872C<$type>'s are known, which can be used to speed up some algorithms.
894 873
895=back 874=back
896 875
897 876
877=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
878
879Opens, reads and closes the given file. The data is put into C<$data>,
880which is resized as required.
881
882If C<$offset> is negative, then it is counted from the end of the file.
883
884If C<$length> is zero, then the remaining length of the file is
885used. Also, in this case, the same limitations to modifying C<$data> apply
886as when IO::AIO::mmap is used, i.e. it must only be modified in-place
887with C<substr>. If the size of the file is known, specifying a non-zero
888C<$length> results in a performance advantage.
889
890This request is similar to the older C<aio_load> request, but since it is
891a single request, it might be more efficient to use.
892
893Example: load F</etc/passwd> into C<$passwd>.
894
895 my $passwd;
896 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
897 $_[0] >= 0
898 or die "/etc/passwd: $!\n";
899
900 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
901 print $passwd;
902 };
903 IO::AIO::flush;
904
905
898=item aio_load $pathname, $data, $callback->($status) 906=item aio_load $pathname, $data, $callback->($status)
899 907
900This is a composite request that tries to fully load the given file into 908This is a composite request that tries to fully load the given file into
901memory. Status is the same as with aio_read. 909memory. Status is the same as with aio_read.
910
911Using C<aio_slurp> might be more efficient, as it is a single request.
902 912
903=cut 913=cut
904 914
905sub aio_load($$;$) { 915sub aio_load($$;$) {
906 my ($path, undef, $cb) = @_; 916 my ($path, undef, $cb) = @_;
… …
926=item aio_copy $srcpath, $dstpath, $callback->($status) 936=item aio_copy $srcpath, $dstpath, $callback->($status)
927 937
928Try to copy the I<file> (directories not supported as either source or 938Try to copy the I<file> (directories not supported as either source or
929destination) from C<$srcpath> to C<$dstpath> and call the callback with 939destination) from C<$srcpath> to C<$dstpath> and call the callback with
930a status of C<0> (ok) or C<-1> (error, see C<$!>). 940a status of C<0> (ok) or C<-1> (error, see C<$!>).
941
942Existing destination files will be truncated.
931 943
932This is a composite request that creates the destination file with 944This is a composite request that creates the destination file with
933mode 0200 and copies the contents of the source file into it using 945mode 0200 and copies the contents of the source file into it using
934C<aio_sendfile>, followed by restoring atime, mtime, access mode and 946C<aio_sendfile>, followed by restoring atime, mtime, access mode and
935uid/gid, in that order. 947uid/gid, in that order.
… …
1045Scans a directory (similar to C<aio_readdir>) but additionally tries to 1057Scans a directory (similar to C<aio_readdir>) but additionally tries to
1046efficiently separate the entries of directory C<$path> into two sets of 1058efficiently separate the entries of directory C<$path> into two sets of
1047names, directories you can recurse into (directories), and ones you cannot 1059names, directories you can recurse into (directories), and ones you cannot
1048recurse into (everything else, including symlinks to directories). 1060recurse into (everything else, including symlinks to directories).
1049 1061
1050C<aio_scandir> is a composite request that creates of many sub requests_ 1062C<aio_scandir> is a composite request that generates many sub requests.
1051C<$maxreq> specifies the maximum number of outstanding aio requests that 1063C<$maxreq> specifies the maximum number of outstanding aio requests that
1052this function generates. If it is C<< <= 0 >>, then a suitable default 1064this function generates. If it is C<< <= 0 >>, then a suitable default
1053will be chosen (currently 4). 1065will be chosen (currently 4).
1054 1066
1055On error, the callback is called without arguments, otherwise it receives 1067On error, the callback is called without arguments, otherwise it receives
… …
1119 aioreq_pri $pri; 1131 aioreq_pri $pri;
1120 add $grp aio_stat $wd, sub { 1132 add $grp aio_stat $wd, sub {
1121 return $grp->result () if $_[0]; 1133 return $grp->result () if $_[0];
1122 my $now = time; 1134 my $now = time;
1123 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1135 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1136 my $rdxflags = READDIR_DIRS_FIRST;
1137
1138 if ((stat _)[3] < 2) {
1139 # at least one non-POSIX filesystem exists
1140 # that returns useful DT_type values: btrfs,
1141 # so optimise for this here by requesting dents
1142 $rdxflags |= READDIR_DENTS;
1143 }
1124 1144
1125 # read the directory entries 1145 # read the directory entries
1126 aioreq_pri $pri; 1146 aioreq_pri $pri;
1127 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1147 add $grp aio_readdirx $wd, $rdxflags, sub {
1128 my $entries = shift 1148 my ($entries, $flags) = @_
1129 or return $grp->result (); 1149 or return $grp->result ();
1150
1151 if ($rdxflags & READDIR_DENTS) {
1152 # if we requested type values, see if we can use them directly.
1153
1154 # if there were any DT_UNKNOWN entries then we assume we
1155 # don't know. alternatively, we could assume that if we get
1156 # one DT_DIR, then all directories are indeed marked with
1157 # DT_DIR, but this seems not required for btrfs, and this
1158 # is basically the "btrfs can't get it's act together" code
1159 # branch.
1160 unless ($flags & READDIR_FOUND_UNKNOWN) {
1161 # now we have valid DT_ information for all entries,
1162 # so use it as an optimisation without further stat's.
1163 # they must also all be at the beginning of @$entries
1164 # by now.
1165
1166 my $dirs;
1167
1168 if (@$entries) {
1169 for (0 .. $#$entries) {
1170 if ($entries->[$_][1] != DT_DIR) {
1171 # splice out directories
1172 $dirs = [splice @$entries, 0, $_];
1173 last;
1174 }
1175 }
1176
1177 # if we didn't find any non-dir, then all entries are dirs
1178 unless ($dirs) {
1179 ($dirs, $entries) = ($entries, []);
1180 }
1181 } else {
1182 # directory is empty, so there are no sbdirs
1183 $dirs = [];
1184 }
1185
1186 # either splice'd the directories out or the dir was empty.
1187 # convert dents to filenames
1188 $_ = $_->[0] for @$dirs;
1189 $_ = $_->[0] for @$entries;
1190
1191 return $grp->result ($dirs, $entries);
1192 }
1193
1194 # cannot use, so return to our old ways
1195 # by pretending we only scanned for names.
1196 $_ = $_->[0] for @$entries;
1197 }
1130 1198
1131 # stat the dir another time 1199 # stat the dir another time
1132 aioreq_pri $pri; 1200 aioreq_pri $pri;
1133 add $grp aio_stat $wd, sub { 1201 add $grp aio_stat $wd, sub {
1134 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1202 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1221 }; 1289 };
1222 1290
1223 $grp 1291 $grp
1224} 1292}
1225 1293
1294=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1295
1296=item aio_ioctl $fh, $request, $buf, $callback->($status)
1297
1298These work just like the C<fcntl> and C<ioctl> built-in functions, except
1299they execute asynchronously and pass the return value to the callback.
1300
1301Both calls can be used for a lot of things, some of which make more sense
1302to run asynchronously in their own thread, while some others make less
1303sense. For example, calls that block waiting for external events, such
1304as locking, will also lock down an I/O thread while it is waiting, which
1305can deadlock the whole I/O system. At the same time, there might be no
1306alternative to using a thread to wait.
1307
1308So in general, you should only use these calls for things that do
1309(filesystem) I/O, not for things that wait for other events (network,
1310other processes), although if you are careful and know what you are doing,
1311you still can.
1312
1313The following constants are available and can be used for normal C<ioctl>
1314and C<fcntl> as well (missing ones are, as usual C<0>):
1315
1316C<F_DUPFD_CLOEXEC>,
1317
1318C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1319
1320C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1321
1322C<F_ADD_SEALS>, C<F_GET_SEALS>, C<F_SEAL_SEAL>, C<F_SEAL_SHRINK>, C<F_SEAL_GROW> and
1323C<F_SEAL_WRITE>.
1324
1325C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1326C<FS_IOC_FIEMAP>.
1327
1328C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1329C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1330
1331C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1332C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1333C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1334C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1335C<FS_FL_USER_MODIFIABLE>.
1336
1337C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1338C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1339C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1340C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1341
1226=item aio_sync $callback->($status) 1342=item aio_sync $callback->($status)
1227 1343
1228Asynchronously call sync and call the callback when finished. 1344Asynchronously call sync and call the callback when finished.
1229 1345
1230=item aio_fsync $fh, $callback->($status) 1346=item aio_fsync $fh, $callback->($status)
… …
1298 }; 1414 };
1299 1415
1300 $grp 1416 $grp
1301} 1417}
1302 1418
1303=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1419=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1304 1420
1305This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1421This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1306scalars (see the C<IO::AIO::mmap> function, although it also works on data 1422scalars (see the C<IO::AIO::mmap> function, although it also works on data
1307scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1423scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1308scalar must only be modified in-place while an aio operation is pending on 1424scalar must only be modified in-place while an aio operation is pending on
… …
1310 1426
1311It calls the C<msync> function of your OS, if available, with the memory 1427It calls the C<msync> function of your OS, if available, with the memory
1312area starting at C<$offset> in the string and ending C<$length> bytes 1428area starting at C<$offset> in the string and ending C<$length> bytes
1313later. If C<$length> is negative, counts from the end, and if C<$length> 1429later. If C<$length> is negative, counts from the end, and if C<$length>
1314is C<undef>, then it goes till the end of the string. The flags can be 1430is C<undef>, then it goes till the end of the string. The flags can be
1315a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1431either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1316C<IO::AIO::MS_SYNC>. 1432C<IO::AIO::MS_INVALIDATE>.
1317 1433
1318=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1434=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1319 1435
1320This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1436This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1321scalars. 1437scalars.
… …
1351 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1467 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1352 aio_mlock $data; # mlock in background 1468 aio_mlock $data; # mlock in background
1353 1469
1354=item aio_mlockall $flags, $callback->($status) 1470=item aio_mlockall $flags, $callback->($status)
1355 1471
1356Calls the C<mlockall> function with the given C<$flags> (a combination of 1472Calls the C<mlockall> function with the given C<$flags> (a
1357C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1473combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1474C<IO::AIO::MCL_ONFAULT>).
1358 1475
1359On systems that do not implement C<mlockall>, this function returns C<-1> 1476On systems that do not implement C<mlockall>, this function returns C<-1>
1360and sets errno to C<ENOSYS>. 1477and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1478by the system result in a return value of C<-1> with errno being set to
1479C<EINVAL>.
1361 1480
1362Note that the corresponding C<munlockall> is synchronous and is 1481Note that the corresponding C<munlockall> is synchronous and is
1363documented under L<MISCELLANEOUS FUNCTIONS>. 1482documented under L<MISCELLANEOUS FUNCTIONS>.
1364 1483
1365Example: asynchronously lock all current and future pages into memory. 1484Example: asynchronously lock all current and future pages into memory.
… …
1404C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1523C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1405C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1524C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1406C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1525C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1407C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1526C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1408 1527
1409At the time of this writing (Linux 3.2), this requets is unreliable unless 1528At the time of this writing (Linux 3.2), this request is unreliable unless
1410C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1529C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1411it to return all extents of a range for files with large number of 1530it to return all extents of a range for files with a large number of
1412extents. The code works around all these issues if C<$count> is undef. 1531extents. The code (only) works around all these issues if C<$count> is
1532C<undef>.
1413 1533
1414=item aio_group $callback->(...) 1534=item aio_group $callback->(...)
1415 1535
1416This is a very special aio request: Instead of doing something, it is a 1536This is a very special aio request: Instead of doing something, it is a
1417container for other aio requests, which is useful if you want to bundle 1537container for other aio requests, which is useful if you want to bundle
… …
1501 aio_stat [$etcdir, "passwd"], sub { 1621 aio_stat [$etcdir, "passwd"], sub {
1502 # yay 1622 # yay
1503 }; 1623 };
1504 }; 1624 };
1505 1625
1506That C<aio_wd> is a request and not a normal function shows that creating 1626The fact that C<aio_wd> is a request and not a normal function shows that
1507an IO::AIO::WD object is itself a potentially blocking operation, which is 1627creating an IO::AIO::WD object is itself a potentially blocking operation,
1508why it is done asynchronously. 1628which is why it is done asynchronously.
1509 1629
1510To stat the directory obtained with C<aio_wd> above, one could write 1630To stat the directory obtained with C<aio_wd> above, one could write
1511either of the following three request calls: 1631either of the following three request calls:
1512 1632
1513 aio_lstat "/etc" , sub { ... # pathname as normal string 1633 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1530There are some caveats: when directories get renamed (or deleted), the 1650There are some caveats: when directories get renamed (or deleted), the
1531pathname string doesn't change, so will point to the new directory (or 1651pathname string doesn't change, so will point to the new directory (or
1532nowhere at all), while the directory fd, if available on the system, 1652nowhere at all), while the directory fd, if available on the system,
1533will still point to the original directory. Most functions accepting a 1653will still point to the original directory. Most functions accepting a
1534pathname will use the directory fd on newer systems, and the string on 1654pathname will use the directory fd on newer systems, and the string on
1535older systems. Some functions (such as realpath) will always rely on the 1655older systems. Some functions (such as C<aio_realpath>) will always rely on
1536string form of the pathname. 1656the string form of the pathname.
1537 1657
1538So this functionality is mainly useful to get some protection against 1658So this functionality is mainly useful to get some protection against
1539C<chdir>, to easily get an absolute path out of a relative path for future 1659C<chdir>, to easily get an absolute path out of a relative path for future
1540reference, and to speed up doing many operations in the same directory 1660reference, and to speed up doing many operations in the same directory
1541(e.g. when stat'ing all files in a directory). 1661(e.g. when stat'ing all files in a directory).
… …
1556passing C<undef> as working directory component of a pathname fails the 1676passing C<undef> as working directory component of a pathname fails the
1557request with C<ENOENT>, there is often no need for error checking in the 1677request with C<ENOENT>, there is often no need for error checking in the
1558C<aio_wd> callback, as future requests using the value will fail in the 1678C<aio_wd> callback, as future requests using the value will fail in the
1559expected way. 1679expected way.
1560 1680
1561If this call isn't available because your OS lacks it or it couldn't be
1562detected, it will be emulated by calling C<fsync> instead.
1563
1564=item IO::AIO::CWD 1681=item IO::AIO::CWD
1565 1682
1566This is a compiletime constant (object) that represents the process 1683This is a compiletime constant (object) that represents the process
1567current working directory. 1684current working directory.
1568 1685
… …
1752The default value for the limit is C<0>, but note that setting a feeder 1869The default value for the limit is C<0>, but note that setting a feeder
1753automatically bumps it up to C<2>. 1870automatically bumps it up to C<2>.
1754 1871
1755=back 1872=back
1756 1873
1874
1757=head2 SUPPORT FUNCTIONS 1875=head2 SUPPORT FUNCTIONS
1758 1876
1759=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1877=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1760 1878
1761=over 4 1879=over 4
… …
1826Strictly equivalent to: 1944Strictly equivalent to:
1827 1945
1828 IO::AIO::poll_wait, IO::AIO::poll_cb 1946 IO::AIO::poll_wait, IO::AIO::poll_cb
1829 while IO::AIO::nreqs; 1947 while IO::AIO::nreqs;
1830 1948
1949This function can be useful at program aborts, to make sure outstanding
1950I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1951this function on normal exits), or when you are merely using C<IO::AIO>
1952for its more advanced functions, rather than for async I/O, e.g.:
1953
1954 my ($dirs, $nondirs);
1955 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1956 IO::AIO::flush;
1957 # $dirs, $nondirs are now set
1958
1831=item IO::AIO::max_poll_reqs $nreqs 1959=item IO::AIO::max_poll_reqs $nreqs
1832 1960
1833=item IO::AIO::max_poll_time $seconds 1961=item IO::AIO::max_poll_time $seconds
1834 1962
1835These set the maximum number of requests (default C<0>, meaning infinity) 1963These set the maximum number of requests (default C<0>, meaning infinity)
… …
1861 poll => 'r', nice => 1, 1989 poll => 'r', nice => 1,
1862 cb => &IO::AIO::poll_cb); 1990 cb => &IO::AIO::poll_cb);
1863 1991
1864=back 1992=back
1865 1993
1994
1866=head3 CONTROLLING THE NUMBER OF THREADS 1995=head3 CONTROLLING THE NUMBER OF THREADS
1867 1996
1868=over 1997=over
1869 1998
1870=item IO::AIO::min_parallel $nthreads 1999=item IO::AIO::min_parallel $nthreads
… …
1935 2064
1936This is a very bad function to use in interactive programs because it 2065This is a very bad function to use in interactive programs because it
1937blocks, and a bad way to reduce concurrency because it is inexact: Better 2066blocks, and a bad way to reduce concurrency because it is inexact: Better
1938use an C<aio_group> together with a feed callback. 2067use an C<aio_group> together with a feed callback.
1939 2068
1940It's main use is in scripts without an event loop - when you want to stat 2069Its main use is in scripts without an event loop - when you want to stat
1941a lot of files, you can write somehting like this: 2070a lot of files, you can write something like this:
1942 2071
1943 IO::AIO::max_outstanding 32; 2072 IO::AIO::max_outstanding 32;
1944 2073
1945 for my $path (...) { 2074 for my $path (...) {
1946 aio_stat $path , ...; 2075 aio_stat $path , ...;
… …
1957The default value for C<max_outstanding> is very large, so there is no 2086The default value for C<max_outstanding> is very large, so there is no
1958practical limit on the number of outstanding requests. 2087practical limit on the number of outstanding requests.
1959 2088
1960=back 2089=back
1961 2090
2091
1962=head3 STATISTICAL INFORMATION 2092=head3 STATISTICAL INFORMATION
1963 2093
1964=over 2094=over
1965 2095
1966=item IO::AIO::nreqs 2096=item IO::AIO::nreqs
… …
1983Returns the number of requests currently in the pending state (executed, 2113Returns the number of requests currently in the pending state (executed,
1984but not yet processed by poll_cb). 2114but not yet processed by poll_cb).
1985 2115
1986=back 2116=back
1987 2117
2118
2119=head3 SUBSECOND STAT TIME ACCESS
2120
2121Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2122generally find access/modification and change times with subsecond time
2123accuracy of the system supports it, but perl's built-in functions only
2124return the integer part.
2125
2126The following functions return the timestamps of the most recent
2127stat with subsecond precision on most systems and work both after
2128C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2129value is only meaningful after a successful C<stat>/C<lstat> call, or
2130during/after a successful C<aio_stat>/C<aio_lstat> callback.
2131
2132This is similar to the L<Time::HiRes> C<stat> functions, but can return
2133full resolution without rounding and work with standard perl C<stat>,
2134alleviating the need to call the special C<Time::HiRes> functions, which
2135do not act like their perl counterparts.
2136
2137On operating systems or file systems where subsecond time resolution is
2138not supported or could not be detected, a fractional part of C<0> is
2139returned, so it is always safe to call these functions.
2140
2141=over 4
2142
2143=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2144
2145Return the access, modication, change or birth time, respectively,
2146including fractional part. Due to the limited precision of floating point,
2147the accuracy on most platforms is only a bit better than milliseconds
2148for times around now - see the I<nsec> function family, below, for full
2149accuracy.
2150
2151File birth time is only available when the OS and perl support it (on
2152FreeBSD and NetBSD at the time of this writing, although support is
2153adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
2154it). On systems where it isn't available, C<0> is currently returned, but
2155this might change to C<undef> in a future version.
2156
2157=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2158
2159Returns access, modification, change and birth time all in one go, and
2160maybe more times in the future version.
2161
2162=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2163
2164Return the fractional access, modifcation, change or birth time, in nanoseconds,
2165as an integer in the range C<0> to C<999999999>.
2166
2167Note that no accessors are provided for access, modification and
2168change times - you need to get those from C<stat _> if required (C<int
2169IO::AIO::st_atime> and so on will I<not> generally give you the correct
2170value).
2171
2172=item $seconds = IO::AIO::st_btimesec
2173
2174The (integral) seconds part of the file birth time, if available.
2175
2176=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2177
2178Like the functions above, but returns all four times in one go (and maybe
2179more in future versions).
2180
2181=item $counter = IO::AIO::st_gen
2182
2183Returns the generation counter (in practice this is just a random number)
2184of the file. This is only available on platforms which have this member in
2185their C<struct stat> (most BSDs at the time of this writing) and generally
2186only to the root usert. If unsupported, C<0> is returned, but this might
2187change to C<undef> in a future version.
2188
2189=back
2190
2191Example: print the high resolution modification time of F</etc>, using
2192C<stat>, and C<IO::AIO::aio_stat>.
2193
2194 if (stat "/etc") {
2195 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2196 }
2197
2198 IO::AIO::aio_stat "/etc", sub {
2199 $_[0]
2200 and return;
2201
2202 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2203 };
2204
2205 IO::AIO::flush;
2206
2207Output of the awbove on my system, showing reduced and full accuracy:
2208
2209 stat(/etc) mtime: 1534043702.020808
2210 aio_stat(/etc) mtime: 1534043702.020807792
2211
2212
1988=head3 MISCELLANEOUS FUNCTIONS 2213=head3 MISCELLANEOUS FUNCTIONS
1989 2214
1990IO::AIO implements some functions that might be useful, but are not 2215IO::AIO implements some functions that are useful when you want to use
1991asynchronous. 2216some "Advanced I/O" function not available to in Perl, without going the
2217"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2218counterpart.
1992 2219
1993=over 4 2220=over 4
2221
2222=item $numfd = IO::AIO::get_fdlimit
2223
2224This function is I<EXPERIMENTAL> and subject to change.
2225
2226Tries to find the current file descriptor limit and returns it, or
2227C<undef> and sets C<$!> in case of an error. The limit is one larger than
2228the highest valid file descriptor number.
2229
2230=item IO::AIO::min_fdlimit [$numfd]
2231
2232This function is I<EXPERIMENTAL> and subject to change.
2233
2234Try to increase the current file descriptor limit(s) to at least C<$numfd>
2235by changing the soft or hard file descriptor resource limit. If C<$numfd>
2236is missing, it will try to set a very high limit, although this is not
2237recommended when you know the actual minimum that you require.
2238
2239If the limit cannot be raised enough, the function makes a best-effort
2240attempt to increase the limit as much as possible, using various
2241tricks, while still failing. You can query the resulting limit using
2242C<IO::AIO::get_fdlimit>.
2243
2244If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2245true.
1994 2246
1995=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2247=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1996 2248
1997Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2249Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1998but is blocking (this makes most sense if you know the input data is 2250but is blocking (this makes most sense if you know the input data is
… …
2015=item IO::AIO::madvise $scalar, $offset, $len, $advice 2267=item IO::AIO::madvise $scalar, $offset, $len, $advice
2016 2268
2017Simply calls the C<posix_madvise> function (see its 2269Simply calls the C<posix_madvise> function (see its
2018manpage for details). The following advice constants are 2270manpage for details). The following advice constants are
2019available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2271available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2020C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2272C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2273C<IO::AIO::MADV_DONTNEED>.
2274
2275If C<$offset> is negative, counts from the end. If C<$length> is negative,
2276the remaining length of the C<$scalar> is used. If possible, C<$length>
2277will be reduced to fit into the C<$scalar>.
2021 2278
2022On systems that do not implement C<posix_madvise>, this function returns 2279On systems that do not implement C<posix_madvise>, this function returns
2023ENOSYS, otherwise the return value of C<posix_madvise>. 2280ENOSYS, otherwise the return value of C<posix_madvise>.
2024 2281
2025=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2282=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2027Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2284Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2028$scalar (see its manpage for details). The following protect 2285$scalar (see its manpage for details). The following protect
2029constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2286constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2030C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2287C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2031 2288
2289If C<$offset> is negative, counts from the end. If C<$length> is negative,
2290the remaining length of the C<$scalar> is used. If possible, C<$length>
2291will be reduced to fit into the C<$scalar>.
2292
2032On systems that do not implement C<mprotect>, this function returns 2293On systems that do not implement C<mprotect>, this function returns
2033ENOSYS, otherwise the return value of C<mprotect>. 2294ENOSYS, otherwise the return value of C<mprotect>.
2034 2295
2035=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2296=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2036 2297
2037Memory-maps a file (or anonymous memory range) and attaches it to the 2298Memory-maps a file (or anonymous memory range) and attaches it to the
2038given C<$scalar>, which will act like a string scalar. Returns true on 2299given C<$scalar>, which will act like a string scalar. Returns true on
2039success, and false otherwise. 2300success, and false otherwise.
2040 2301
2302The scalar must exist, but its contents do not matter - this means you
2303cannot use a nonexistant array or hash element. When in doubt, C<undef>
2304the scalar first.
2305
2041The only operations allowed on the scalar are C<substr>/C<vec> that don't 2306The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2042change the string length, and most read-only operations such as copying it 2307which don't change the string length, and most read-only operations such
2043or searching it with regexes and so on. 2308as copying it or searching it with regexes and so on.
2044 2309
2045Anything else is unsafe and will, at best, result in memory leaks. 2310Anything else is unsafe and will, at best, result in memory leaks.
2046 2311
2047The memory map associated with the C<$scalar> is automatically removed 2312The memory map associated with the C<$scalar> is automatically removed
2048when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2313when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2049C<IO::AIO::munmap> functions are called. 2314or C<IO::AIO::munmap> functions are called on it.
2050 2315
2051This calls the C<mmap>(2) function internally. See your system's manual 2316This calls the C<mmap>(2) function internally. See your system's manual
2052page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2317page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2053 2318
2054The C<$length> must be larger than zero and smaller than the actual 2319The C<$length> must be larger than zero and smaller than the actual
2055filesize. 2320filesize.
2056 2321
2057C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2322C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2058C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2323C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2059 2324
2060C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2325C<$flags> can be a combination of
2061C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2326C<IO::AIO::MAP_SHARED> or
2062not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2327C<IO::AIO::MAP_PRIVATE>,
2328or a number of system-specific flags (when not available, the are C<0>):
2063(which is set to C<MAP_ANON> if your system only provides this 2329C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2064constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2330C<IO::AIO::MAP_LOCKED>,
2065C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2331C<IO::AIO::MAP_NORESERVE>,
2332C<IO::AIO::MAP_POPULATE>,
2066C<IO::AIO::MAP_NONBLOCK> 2333C<IO::AIO::MAP_NONBLOCK>,
2334C<IO::AIO::MAP_FIXED>,
2335C<IO::AIO::MAP_GROWSDOWN>,
2336C<IO::AIO::MAP_32BIT>,
2337C<IO::AIO::MAP_HUGETLB> or
2338C<IO::AIO::MAP_STACK>.
2067 2339
2068If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2340If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2069 2341
2070C<$offset> is the offset from the start of the file - it generally must be 2342C<$offset> is the offset from the start of the file - it generally must be
2071a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2343a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2084 my $fast_md5 = md5 $data; 2356 my $fast_md5 = md5 $data;
2085 2357
2086=item IO::AIO::munmap $scalar 2358=item IO::AIO::munmap $scalar
2087 2359
2088Removes a previous mmap and undefines the C<$scalar>. 2360Removes a previous mmap and undefines the C<$scalar>.
2361
2362=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2363
2364Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2365been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2366C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2367
2368Returns true if successful, and false otherwise. If the underlying mmapped
2369region has changed address, then the true value has the numerical value
2370C<1>, otherwise it has the numerical value C<0>:
2371
2372 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2373 or die "mremap: $!";
2374
2375 if ($success*1) {
2376 warn "scalar has chanegd address in memory\n";
2377 }
2378
2379C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2380implemented, but not supported and might go away in a future version.
2381
2382On systems where this call is not supported or is not emulated, this call
2383returns falls and sets C<$!> to C<ENOSYS>.
2384
2385=item IO::AIO::mlockall $flags
2386
2387Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2388but is blocking.
2089 2389
2090=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2390=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2091 2391
2092Calls the C<munlock> function, undoing the effects of a previous 2392Calls the C<munlock> function, undoing the effects of a previous
2093C<aio_mlock> call (see its description for details). 2393C<aio_mlock> call (see its description for details).
… …
2114 2414
2115See the C<splice(2)> manpage for details. 2415See the C<splice(2)> manpage for details.
2116 2416
2117=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2417=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2118 2418
2119Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2419Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2120description for C<IO::AIO::splice> above for details. 2420description for C<IO::AIO::splice> above for details.
2421
2422=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2423
2424Attempts to query or change the pipe buffer size. Obviously works only
2425on pipes, and currently works only on GNU/Linux systems, and fails with
2426C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2427size on other systems, drop me a note.
2428
2429=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2430
2431This is a direct interface to the Linux L<pipe2(2)> system call. If
2432C<$flags> is missing or C<0>, then this should be the same as a call to
2433perl's built-in C<pipe> function and create a new pipe, and works on
2434systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2435(..., 4096, O_BINARY)>.
2436
2437If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2438the given flags (Linux 2.6.27, glibc 2.9).
2439
2440On success, the read and write file handles are returned.
2441
2442On error, nothing will be returned. If the pipe2 syscall is missing and
2443C<$flags> is non-zero, fails with C<ENOSYS>.
2444
2445Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2446time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2447C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2448
2449Example: create a pipe race-free w.r.t. threads and fork:
2450
2451 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2452 or die "pipe2: $!\n";
2453
2454=item $fh = IO::AIO::memfd_create $pathname[, $flags]
2455
2456This is a direct interface to the Linux L<memfd_create(2)> system
2457call. The (unhelpful) default for C<$flags> is C<0>, but your default
2458should be C<IO::AIO::MFD_CLOEXEC>.
2459
2460On success, the new memfd filehandle is returned, otherwise returns
2461C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
2462
2463Please refer to L<memfd_create(2)> for more info on this call.
2464
2465The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
2466C<IO::AIO::MFD_ALLOW_SEALING> and C<IO::AIO::MFD_HUGETLB>.
2467
2468Example: create a new memfd.
2469
2470 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2471 or die "m,emfd_create: $!\n";
2472=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2473
2474This is a direct interface to the Linux L<eventfd(2)> system call. The
2475(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2476
2477On success, the new eventfd filehandle is returned, otherwise returns
2478C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2479
2480Please refer to L<eventfd(2)> for more info on this call.
2481
2482The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2483C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2484
2485Example: create a new eventfd filehandle:
2486
2487 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2488 or die "eventfd: $!\n";
2489
2490=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2491
2492This is a direct interface to the Linux L<timerfd_create(2)> system
2493call. The (unhelpful) default for C<$flags> is C<0>, but your default
2494should be C<IO::AIO::TFD_CLOEXEC>.
2495
2496On success, the new timerfd filehandle is returned, otherwise returns
2497C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
2498
2499Please refer to L<timerfd_create(2)> for more info on this call.
2500
2501The following C<$clockid> values are
2502available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2503C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2504C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2505C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2506
2507The following C<$flags> values are available (Linux
25082.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2509
2510Example: create a new timerfd and set it to one-second repeated alarms,
2511then wait for two alarms:
2512
2513 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2514 or die "timerfd_create: $!\n";
2515
2516 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2517 or die "timerfd_settime: $!\n";
2518
2519 for (1..2) {
2520 8 == sysread $fh, my $buf, 8
2521 or die "timerfd read failure\n";
2522
2523 printf "number of expirations (likely 1): %d\n",
2524 unpack "Q", $buf;
2525 }
2526
2527=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2528
2529This is a direct interface to the Linux L<timerfd_settime(2)> system
2530call. Please refer to its manpage for more info on this call.
2531
2532The new itimerspec is specified using two (possibly fractional) second
2533values, C<$new_interval> and C<$new_value>).
2534
2535On success, the current interval and value are returned (as per
2536C<timerfd_gettime>). On failure, the empty list is returned.
2537
2538The following C<$flags> values are
2539available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2540C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2541
2542See C<IO::AIO::timerfd_create> for a full example.
2543
2544=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2545
2546This is a direct interface to the Linux L<timerfd_gettime(2)> system
2547call. Please refer to its manpage for more info on this call.
2548
2549On success, returns the current values of interval and value for the given
2550timerfd (as potentially fractional second values). On failure, the empty
2551list is returned.
2121 2552
2122=back 2553=back
2123 2554
2124=cut 2555=cut
2125 2556
… …
2191the process will result in undefined behaviour. Calling it at any time 2622the process will result in undefined behaviour. Calling it at any time
2192will also result in any undefined (by POSIX) behaviour. 2623will also result in any undefined (by POSIX) behaviour.
2193 2624
2194=back 2625=back
2195 2626
2627=head2 LINUX-SPECIFIC CALLS
2628
2629When a call is documented as "linux-specific" then this means it
2630originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2631availability and compatibility of such calls regardless of the platform
2632it is compiled on, so platforms such as FreeBSD which often implement
2633these calls will work. When in doubt, call them and see if they fail wth
2634C<ENOSYS>.
2635
2196=head2 MEMORY USAGE 2636=head2 MEMORY USAGE
2197 2637
2198Per-request usage: 2638Per-request usage:
2199 2639
2200Each aio request uses - depending on your architecture - around 100-200 2640Each aio request uses - depending on your architecture - around 100-200
… …
2212temporary buffers, and each thread requires a stack and other data 2652temporary buffers, and each thread requires a stack and other data
2213structures (usually around 16k-128k, depending on the OS). 2653structures (usually around 16k-128k, depending on the OS).
2214 2654
2215=head1 KNOWN BUGS 2655=head1 KNOWN BUGS
2216 2656
2217Known bugs will be fixed in the next release. 2657Known bugs will be fixed in the next release :)
2658
2659=head1 KNOWN ISSUES
2660
2661Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2662or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2663non-created hash slots or other scalars I didn't think of. It's best to
2664avoid such and either use scalar variables or making sure that the scalar
2665exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2666
2667I am not sure anything can be done about this, so this is considered a
2668known issue, rather than a bug.
2218 2669
2219=head1 SEE ALSO 2670=head1 SEE ALSO
2220 2671
2221L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2672L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2222more natural syntax. 2673more natural syntax and L<IO::FDPass> for file descriptor passing.
2223 2674
2224=head1 AUTHOR 2675=head1 AUTHOR
2225 2676
2226 Marc Lehmann <schmorp@schmorp.de> 2677 Marc Lehmann <schmorp@schmorp.de>
2227 http://home.schmorp.de/ 2678 http://home.schmorp.de/

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