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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 1.306 by root, Wed Oct 16 09:11:35 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 = 4.73;
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::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
309 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
310 IO::AIO::tee $r_fh, $w_fh, $length, $flags
311 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
312 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
313 $fh = IO::AIO::memfd_create $pathname[, $flags]
314 $fh = IO::AIO::eventfd [$initval, [$flags]]
315 $fh = IO::AIO::timerfd_create $clockid[, $flags]
316 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
317 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
285 318
286=head2 API NOTES 319=head2 API NOTES
287 320
288All the C<aio_*> calls are more or less thin wrappers around the syscall 321All 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, 322with the same name (sans C<aio_>). The arguments are similar or identical,
… …
395following POSIX and non-POSIX constants are available (missing ones on 428following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 429your system are, as usual, C<0>):
397 430
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 431C<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>, 432C<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>. 433C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
401 434
402 435
403=item aio_close $fh, $callback->($status) 436=item aio_close $fh, $callback->($status)
404 437
405Asynchronously close a file and call the callback with the result 438Asynchronously close a file and call the callback with the result
… …
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 473=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 474
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 475=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 476
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 477Reads 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<$dataoffset> 478C<$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 479calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 480error, just like the syscall).
448 481
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 482C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 483offset plus the actual number of bytes read.
451 484
… …
509As native sendfile syscalls (as practically any non-POSIX interface hacked 542As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 543together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 544on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 545in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 546so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 547fewer bytes than expected might have been transferred.
515 548
516 549
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 550=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 551
519C<aio_readahead> populates the page cache with data from a file so that 552C<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 556whole 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 557and 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 558(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. 559file. The current file offset of the file is left unchanged.
527 560
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 561If 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. 562be emulated by simply reading the data, which would have a similar effect.
530 563
531 564
532=item aio_stat $fh_or_path, $callback->($status) 565=item aio_stat $fh_or_path, $callback->($status)
533 566
534=item aio_lstat $fh, $callback->($status) 567=item aio_lstat $fh, $callback->($status)
535 568
536Works like perl's C<stat> or C<lstat> in void context. The callback will 569Works 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 _> 570callback will be called after the stat and the results will be available
538or C<-s _> etc... 571using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
572and C<-T>).
539 573
540The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 574The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
541for an explanation. 575for an explanation.
542 576
543Currently, the stats are always 64-bit-stats, i.e. instead of returning an 577Currently, the stats are always 64-bit-stats, i.e. instead of returning an
… …
550behaviour). 584behaviour).
551 585
552C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 586C<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>, 587C<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>. 588C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
589
590To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
591ACCESS>.
555 592
556Example: Print the length of F</etc/passwd>: 593Example: Print the length of F</etc/passwd>:
557 594
558 aio_stat "/etc/passwd", sub { 595 aio_stat "/etc/passwd", sub {
559 $_[0] and die "stat failed: $!"; 596 $_[0] and die "stat failed: $!";
… …
603 namemax => 255, 640 namemax => 255,
604 frsize => 1024, 641 frsize => 1024,
605 fsid => 1810 642 fsid => 1810
606 } 643 }
607 644
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) 645=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
691 646
692Works like perl's C<utime> function (including the special case of $atime 647Works like perl's C<utime> function (including the special case of $atime
693and $mtime being undef). Fractional times are supported if the underlying 648and $mtime being undef). Fractional times are supported if the underlying
694syscalls support them. 649syscalls support them.
695 650
696When called with a pathname, uses utimes(2) if available, otherwise 651When 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, 652otherwise utime(2). If called on a file descriptor, uses futimens(2)
698otherwise returns ENOSYS, so this is not portable. 653or futimes(2) if available, otherwise returns ENOSYS, so this is not
654portable.
699 655
700Examples: 656Examples:
701 657
702 # set atime and mtime to current time (basically touch(1)): 658 # set atime and mtime to current time (basically touch(1)):
703 aio_utime "path", undef, undef; 659 aio_utime "path", undef, undef;
… …
723Works like truncate(2) or ftruncate(2). 679Works like truncate(2) or ftruncate(2).
724 680
725 681
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 682=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727 683
728Allocates or freed disk space according to the C<$mode> argument. See the 684Allocates or frees disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details. 685linux C<fallocate> documentation for details.
730 686
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 687C<$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 | 688space, 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. 689to deallocate a file range.
690
691IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
692(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
693C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
694to unshare shared blocks (see your L<fallocate(2)> manpage).
734 695
735The file system block size used by C<fallocate> is presumably the 696The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>. 697C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
698can dictate other limitations.
737 699
738If C<fallocate> isn't available or cannot be emulated (currently no 700If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 701emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740 702
741 703
… …
800On systems that support the AIO::WD working directory abstraction 762On systems that support the AIO::WD working directory abstraction
801natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 763natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
802of failing, C<rename> is called on the absolute path of C<$wd>. 764of failing, C<rename> is called on the absolute path of C<$wd>.
803 765
804 766
767=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
768
769Basically a version of C<aio_rename> with an additional C<$flags>
770argument. Calling this with C<$flags=0> is the same as calling
771C<aio_rename>.
772
773Non-zero flags are currently only supported on GNU/Linux systems that
774support renameat2. Other systems fail with C<ENOSYS> in this case.
775
776The following constants are available (missing ones are, as usual C<0>),
777see renameat2(2) for details:
778
779C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
780and C<IO::AIO::RENAME_WHITEOUT>.
781
782
805=item aio_mkdir $pathname, $mode, $callback->($status) 783=item aio_mkdir $pathname, $mode, $callback->($status)
806 784
807Asynchronously mkdir (create) a directory and call the callback with 785Asynchronously mkdir (create) a directory and call the callback with
808the result code. C<$mode> will be modified by the umask at the time the 786the result code. C<$mode> will be modified by the umask at the time the
809request is executed, so do not change your umask. 787request is executed, so do not change your umask.
… …
840 818
841=over 4 819=over 4
842 820
843=item IO::AIO::READDIR_DENTS 821=item IO::AIO::READDIR_DENTS
844 822
845When this flag is off, then the callback gets an arrayref consisting of 823Normally the callback gets an arrayref consisting of names only (as
846names only (as with C<aio_readdir>), otherwise it gets an arrayref with 824with C<aio_readdir>). If this flag is set, then the callback gets an
847C<[$name, $type, $inode]> arrayrefs, each describing a single directory 825arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
848entry in more detail. 826single directory entry in more detail:
849 827
850C<$name> is the name of the entry. 828C<$name> is the name of the entry.
851 829
852C<$type> is one of the C<IO::AIO::DT_xxx> constants: 830C<$type> is one of the C<IO::AIO::DT_xxx> constants:
853 831
854C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 832C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
855C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 833C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
856C<IO::AIO::DT_WHT>. 834C<IO::AIO::DT_WHT>.
857 835
858C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 836C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
859know, you have to run stat yourself. Also, for speed reasons, the C<$type> 837to know, you have to run stat yourself. Also, for speed/memory reasons,
860scalars are read-only: you can not modify them. 838the C<$type> scalars are read-only: you must not modify them.
861 839
862C<$inode> is the inode number (which might not be exact on systems with 64 840C<$inode> is the inode number (which might not be exact on systems with 64
863bit inode numbers and 32 bit perls). This field has unspecified content on 841bit inode numbers and 32 bit perls). This field has unspecified content on
864systems that do not deliver the inode information. 842systems that do not deliver the inode information.
865 843
… …
876short names are tried first. 854short names are tried first.
877 855
878=item IO::AIO::READDIR_STAT_ORDER 856=item IO::AIO::READDIR_STAT_ORDER
879 857
880When this flag is set, then the names will be returned in an order 858When this flag is set, then the names will be returned in an order
881suitable for stat()'ing each one. That is, when you plan to stat() 859suitable for stat()'ing each one. That is, when you plan to stat() most or
882all files in the given directory, then the returned order will likely 860all files in the given directory, then the returned order will likely be
883be fastest. 861faster.
884 862
885If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 863If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
886the likely dirs come first, resulting in a less optimal stat order. 864then the likely dirs come first, resulting in a less optimal stat order
865for stat'ing all entries, but likely a more optimal order for finding
866subdirectories.
887 867
888=item IO::AIO::READDIR_FOUND_UNKNOWN 868=item IO::AIO::READDIR_FOUND_UNKNOWN
889 869
890This flag should not be set when calling C<aio_readdirx>. Instead, it 870This flag should not be set when calling C<aio_readdirx>. Instead, it
891is being set by C<aio_readdirx>, when any of the C<$type>'s found were 871is 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. 873C<$type>'s are known, which can be used to speed up some algorithms.
894 874
895=back 875=back
896 876
897 877
878=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
879
880Opens, reads and closes the given file. The data is put into C<$data>,
881which is resized as required.
882
883If C<$offset> is negative, then it is counted from the end of the file.
884
885If C<$length> is zero, then the remaining length of the file is
886used. Also, in this case, the same limitations to modifying C<$data> apply
887as when IO::AIO::mmap is used, i.e. it must only be modified in-place
888with C<substr>. If the size of the file is known, specifying a non-zero
889C<$length> results in a performance advantage.
890
891This request is similar to the older C<aio_load> request, but since it is
892a single request, it might be more efficient to use.
893
894Example: load F</etc/passwd> into C<$passwd>.
895
896 my $passwd;
897 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
898 $_[0] >= 0
899 or die "/etc/passwd: $!\n";
900
901 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
902 print $passwd;
903 };
904 IO::AIO::flush;
905
906
898=item aio_load $pathname, $data, $callback->($status) 907=item aio_load $pathname, $data, $callback->($status)
899 908
900This is a composite request that tries to fully load the given file into 909This is a composite request that tries to fully load the given file into
901memory. Status is the same as with aio_read. 910memory. Status is the same as with aio_read.
911
912Using C<aio_slurp> might be more efficient, as it is a single request.
902 913
903=cut 914=cut
904 915
905sub aio_load($$;$) { 916sub aio_load($$;$) {
906 my ($path, undef, $cb) = @_; 917 my ($path, undef, $cb) = @_;
… …
926=item aio_copy $srcpath, $dstpath, $callback->($status) 937=item aio_copy $srcpath, $dstpath, $callback->($status)
927 938
928Try to copy the I<file> (directories not supported as either source or 939Try to copy the I<file> (directories not supported as either source or
929destination) from C<$srcpath> to C<$dstpath> and call the callback with 940destination) from C<$srcpath> to C<$dstpath> and call the callback with
930a status of C<0> (ok) or C<-1> (error, see C<$!>). 941a status of C<0> (ok) or C<-1> (error, see C<$!>).
942
943Existing destination files will be truncated.
931 944
932This is a composite request that creates the destination file with 945This is a composite request that creates the destination file with
933mode 0200 and copies the contents of the source file into it using 946mode 0200 and copies the contents of the source file into it using
934C<aio_sendfile>, followed by restoring atime, mtime, access mode and 947C<aio_sendfile>, followed by restoring atime, mtime, access mode and
935uid/gid, in that order. 948uid/gid, in that order.
… …
1045Scans a directory (similar to C<aio_readdir>) but additionally tries to 1058Scans a directory (similar to C<aio_readdir>) but additionally tries to
1046efficiently separate the entries of directory C<$path> into two sets of 1059efficiently separate the entries of directory C<$path> into two sets of
1047names, directories you can recurse into (directories), and ones you cannot 1060names, directories you can recurse into (directories), and ones you cannot
1048recurse into (everything else, including symlinks to directories). 1061recurse into (everything else, including symlinks to directories).
1049 1062
1050C<aio_scandir> is a composite request that creates of many sub requests_ 1063C<aio_scandir> is a composite request that generates many sub requests.
1051C<$maxreq> specifies the maximum number of outstanding aio requests that 1064C<$maxreq> specifies the maximum number of outstanding aio requests that
1052this function generates. If it is C<< <= 0 >>, then a suitable default 1065this function generates. If it is C<< <= 0 >>, then a suitable default
1053will be chosen (currently 4). 1066will be chosen (currently 4).
1054 1067
1055On error, the callback is called without arguments, otherwise it receives 1068On error, the callback is called without arguments, otherwise it receives
… …
1119 aioreq_pri $pri; 1132 aioreq_pri $pri;
1120 add $grp aio_stat $wd, sub { 1133 add $grp aio_stat $wd, sub {
1121 return $grp->result () if $_[0]; 1134 return $grp->result () if $_[0];
1122 my $now = time; 1135 my $now = time;
1123 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1136 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1137 my $rdxflags = READDIR_DIRS_FIRST;
1138
1139 if ((stat _)[3] < 2) {
1140 # at least one non-POSIX filesystem exists
1141 # that returns useful DT_type values: btrfs,
1142 # so optimise for this here by requesting dents
1143 $rdxflags |= READDIR_DENTS;
1144 }
1124 1145
1125 # read the directory entries 1146 # read the directory entries
1126 aioreq_pri $pri; 1147 aioreq_pri $pri;
1127 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1148 add $grp aio_readdirx $wd, $rdxflags, sub {
1128 my $entries = shift 1149 my ($entries, $flags) = @_
1129 or return $grp->result (); 1150 or return $grp->result ();
1151
1152 if ($rdxflags & READDIR_DENTS) {
1153 # if we requested type values, see if we can use them directly.
1154
1155 # if there were any DT_UNKNOWN entries then we assume we
1156 # don't know. alternatively, we could assume that if we get
1157 # one DT_DIR, then all directories are indeed marked with
1158 # DT_DIR, but this seems not required for btrfs, and this
1159 # is basically the "btrfs can't get it's act together" code
1160 # branch.
1161 unless ($flags & READDIR_FOUND_UNKNOWN) {
1162 # now we have valid DT_ information for all entries,
1163 # so use it as an optimisation without further stat's.
1164 # they must also all be at the beginning of @$entries
1165 # by now.
1166
1167 my $dirs;
1168
1169 if (@$entries) {
1170 for (0 .. $#$entries) {
1171 if ($entries->[$_][1] != DT_DIR) {
1172 # splice out directories
1173 $dirs = [splice @$entries, 0, $_];
1174 last;
1175 }
1176 }
1177
1178 # if we didn't find any non-dir, then all entries are dirs
1179 unless ($dirs) {
1180 ($dirs, $entries) = ($entries, []);
1181 }
1182 } else {
1183 # directory is empty, so there are no sbdirs
1184 $dirs = [];
1185 }
1186
1187 # either splice'd the directories out or the dir was empty.
1188 # convert dents to filenames
1189 $_ = $_->[0] for @$dirs;
1190 $_ = $_->[0] for @$entries;
1191
1192 return $grp->result ($dirs, $entries);
1193 }
1194
1195 # cannot use, so return to our old ways
1196 # by pretending we only scanned for names.
1197 $_ = $_->[0] for @$entries;
1198 }
1130 1199
1131 # stat the dir another time 1200 # stat the dir another time
1132 aioreq_pri $pri; 1201 aioreq_pri $pri;
1133 add $grp aio_stat $wd, sub { 1202 add $grp aio_stat $wd, sub {
1134 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1203 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1221 }; 1290 };
1222 1291
1223 $grp 1292 $grp
1224} 1293}
1225 1294
1295=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1296
1297=item aio_ioctl $fh, $request, $buf, $callback->($status)
1298
1299These work just like the C<fcntl> and C<ioctl> built-in functions, except
1300they execute asynchronously and pass the return value to the callback.
1301
1302Both calls can be used for a lot of things, some of which make more sense
1303to run asynchronously in their own thread, while some others make less
1304sense. For example, calls that block waiting for external events, such
1305as locking, will also lock down an I/O thread while it is waiting, which
1306can deadlock the whole I/O system. At the same time, there might be no
1307alternative to using a thread to wait.
1308
1309So in general, you should only use these calls for things that do
1310(filesystem) I/O, not for things that wait for other events (network,
1311other processes), although if you are careful and know what you are doing,
1312you still can.
1313
1314The following constants are available and can be used for normal C<ioctl>
1315and C<fcntl> as well (missing ones are, as usual C<0>):
1316
1317C<F_DUPFD_CLOEXEC>,
1318
1319C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1320
1321C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1322
1323C<F_ADD_SEALS>, C<F_GET_SEALS>, C<F_SEAL_SEAL>, C<F_SEAL_SHRINK>, C<F_SEAL_GROW> and
1324C<F_SEAL_WRITE>.
1325
1326C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1327C<FS_IOC_FIEMAP>.
1328
1329C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1330C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1331
1332C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1333C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1334C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1335C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1336C<FS_FL_USER_MODIFIABLE>.
1337
1338C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1339C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1340C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1341C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1342
1226=item aio_sync $callback->($status) 1343=item aio_sync $callback->($status)
1227 1344
1228Asynchronously call sync and call the callback when finished. 1345Asynchronously call sync and call the callback when finished.
1229 1346
1230=item aio_fsync $fh, $callback->($status) 1347=item aio_fsync $fh, $callback->($status)
… …
1298 }; 1415 };
1299 1416
1300 $grp 1417 $grp
1301} 1418}
1302 1419
1303=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1420=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1304 1421
1305This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1422This 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 1423scalars (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 1424scalars 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 1425scalar must only be modified in-place while an aio operation is pending on
… …
1310 1427
1311It calls the C<msync> function of your OS, if available, with the memory 1428It 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 1429area 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> 1430later. 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 1431is 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 1432either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1316C<IO::AIO::MS_SYNC>. 1433C<IO::AIO::MS_INVALIDATE>.
1317 1434
1318=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1435=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1319 1436
1320This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1437This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1321scalars. 1438scalars.
… …
1351 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1468 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1352 aio_mlock $data; # mlock in background 1469 aio_mlock $data; # mlock in background
1353 1470
1354=item aio_mlockall $flags, $callback->($status) 1471=item aio_mlockall $flags, $callback->($status)
1355 1472
1356Calls the C<mlockall> function with the given C<$flags> (a combination of 1473Calls the C<mlockall> function with the given C<$flags> (a
1357C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1474combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1475C<IO::AIO::MCL_ONFAULT>).
1358 1476
1359On systems that do not implement C<mlockall>, this function returns C<-1> 1477On systems that do not implement C<mlockall>, this function returns C<-1>
1360and sets errno to C<ENOSYS>. 1478and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1479by the system result in a return value of C<-1> with errno being set to
1480C<EINVAL>.
1361 1481
1362Note that the corresponding C<munlockall> is synchronous and is 1482Note that the corresponding C<munlockall> is synchronous and is
1363documented under L<MISCELLANEOUS FUNCTIONS>. 1483documented under L<MISCELLANEOUS FUNCTIONS>.
1364 1484
1365Example: asynchronously lock all current and future pages into memory. 1485Example: asynchronously lock all current and future pages into memory.
… …
1404C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1524C<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>, 1525C<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 1526C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1407C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1527C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1408 1528
1409At the time of this writing (Linux 3.2), this requets is unreliable unless 1529At the time of this writing (Linux 3.2), this request is unreliable unless
1410C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1530C<$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 1531it to return all extents of a range for files with a large number of
1412extents. The code works around all these issues if C<$count> is undef. 1532extents. The code (only) works around all these issues if C<$count> is
1533C<undef>.
1413 1534
1414=item aio_group $callback->(...) 1535=item aio_group $callback->(...)
1415 1536
1416This is a very special aio request: Instead of doing something, it is a 1537This is a very special aio request: Instead of doing something, it is a
1417container for other aio requests, which is useful if you want to bundle 1538container for other aio requests, which is useful if you want to bundle
… …
1501 aio_stat [$etcdir, "passwd"], sub { 1622 aio_stat [$etcdir, "passwd"], sub {
1502 # yay 1623 # yay
1503 }; 1624 };
1504 }; 1625 };
1505 1626
1506That C<aio_wd> is a request and not a normal function shows that creating 1627The 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 1628creating an IO::AIO::WD object is itself a potentially blocking operation,
1508why it is done asynchronously. 1629which is why it is done asynchronously.
1509 1630
1510To stat the directory obtained with C<aio_wd> above, one could write 1631To stat the directory obtained with C<aio_wd> above, one could write
1511either of the following three request calls: 1632either of the following three request calls:
1512 1633
1513 aio_lstat "/etc" , sub { ... # pathname as normal string 1634 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1530There are some caveats: when directories get renamed (or deleted), the 1651There are some caveats: when directories get renamed (or deleted), the
1531pathname string doesn't change, so will point to the new directory (or 1652pathname string doesn't change, so will point to the new directory (or
1532nowhere at all), while the directory fd, if available on the system, 1653nowhere at all), while the directory fd, if available on the system,
1533will still point to the original directory. Most functions accepting a 1654will still point to the original directory. Most functions accepting a
1534pathname will use the directory fd on newer systems, and the string on 1655pathname will use the directory fd on newer systems, and the string on
1535older systems. Some functions (such as realpath) will always rely on the 1656older systems. Some functions (such as C<aio_realpath>) will always rely on
1536string form of the pathname. 1657the string form of the pathname.
1537 1658
1538So this functionality is mainly useful to get some protection against 1659So 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 1660C<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 1661reference, and to speed up doing many operations in the same directory
1541(e.g. when stat'ing all files in a directory). 1662(e.g. when stat'ing all files in a directory).
… …
1556passing C<undef> as working directory component of a pathname fails the 1677passing 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 1678request 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 1679C<aio_wd> callback, as future requests using the value will fail in the
1559expected way. 1680expected way.
1560 1681
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 1682=item IO::AIO::CWD
1565 1683
1566This is a compiletime constant (object) that represents the process 1684This is a compile time constant (object) that represents the process
1567current working directory. 1685current working directory.
1568 1686
1569Specifying this object as working directory object for a pathname is as if 1687Specifying this object as working directory object for a pathname is as if
1570the pathname would be specified directly, without a directory object. For 1688the pathname would be specified directly, without a directory object. For
1571example, these calls are functionally identical: 1689example, these calls are functionally identical:
… …
1752The default value for the limit is C<0>, but note that setting a feeder 1870The default value for the limit is C<0>, but note that setting a feeder
1753automatically bumps it up to C<2>. 1871automatically bumps it up to C<2>.
1754 1872
1755=back 1873=back
1756 1874
1875
1757=head2 SUPPORT FUNCTIONS 1876=head2 SUPPORT FUNCTIONS
1758 1877
1759=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1878=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1760 1879
1761=over 4 1880=over 4
… …
1826Strictly equivalent to: 1945Strictly equivalent to:
1827 1946
1828 IO::AIO::poll_wait, IO::AIO::poll_cb 1947 IO::AIO::poll_wait, IO::AIO::poll_cb
1829 while IO::AIO::nreqs; 1948 while IO::AIO::nreqs;
1830 1949
1950This function can be useful at program aborts, to make sure outstanding
1951I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1952this function on normal exits), or when you are merely using C<IO::AIO>
1953for its more advanced functions, rather than for async I/O, e.g.:
1954
1955 my ($dirs, $nondirs);
1956 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1957 IO::AIO::flush;
1958 # $dirs, $nondirs are now set
1959
1831=item IO::AIO::max_poll_reqs $nreqs 1960=item IO::AIO::max_poll_reqs $nreqs
1832 1961
1833=item IO::AIO::max_poll_time $seconds 1962=item IO::AIO::max_poll_time $seconds
1834 1963
1835These set the maximum number of requests (default C<0>, meaning infinity) 1964These set the maximum number of requests (default C<0>, meaning infinity)
… …
1861 poll => 'r', nice => 1, 1990 poll => 'r', nice => 1,
1862 cb => &IO::AIO::poll_cb); 1991 cb => &IO::AIO::poll_cb);
1863 1992
1864=back 1993=back
1865 1994
1995
1866=head3 CONTROLLING THE NUMBER OF THREADS 1996=head3 CONTROLLING THE NUMBER OF THREADS
1867 1997
1868=over 1998=over
1869 1999
1870=item IO::AIO::min_parallel $nthreads 2000=item IO::AIO::min_parallel $nthreads
… …
1935 2065
1936This is a very bad function to use in interactive programs because it 2066This 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 2067blocks, and a bad way to reduce concurrency because it is inexact: Better
1938use an C<aio_group> together with a feed callback. 2068use an C<aio_group> together with a feed callback.
1939 2069
1940It's main use is in scripts without an event loop - when you want to stat 2070Its main use is in scripts without an event loop - when you want to stat
1941a lot of files, you can write somehting like this: 2071a lot of files, you can write something like this:
1942 2072
1943 IO::AIO::max_outstanding 32; 2073 IO::AIO::max_outstanding 32;
1944 2074
1945 for my $path (...) { 2075 for my $path (...) {
1946 aio_stat $path , ...; 2076 aio_stat $path , ...;
… …
1957The default value for C<max_outstanding> is very large, so there is no 2087The default value for C<max_outstanding> is very large, so there is no
1958practical limit on the number of outstanding requests. 2088practical limit on the number of outstanding requests.
1959 2089
1960=back 2090=back
1961 2091
2092
1962=head3 STATISTICAL INFORMATION 2093=head3 STATISTICAL INFORMATION
1963 2094
1964=over 2095=over
1965 2096
1966=item IO::AIO::nreqs 2097=item IO::AIO::nreqs
… …
1983Returns the number of requests currently in the pending state (executed, 2114Returns the number of requests currently in the pending state (executed,
1984but not yet processed by poll_cb). 2115but not yet processed by poll_cb).
1985 2116
1986=back 2117=back
1987 2118
2119
2120=head3 SUBSECOND STAT TIME ACCESS
2121
2122Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2123generally find access/modification and change times with subsecond time
2124accuracy of the system supports it, but perl's built-in functions only
2125return the integer part.
2126
2127The following functions return the timestamps of the most recent
2128stat with subsecond precision on most systems and work both after
2129C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2130value is only meaningful after a successful C<stat>/C<lstat> call, or
2131during/after a successful C<aio_stat>/C<aio_lstat> callback.
2132
2133This is similar to the L<Time::HiRes> C<stat> functions, but can return
2134full resolution without rounding and work with standard perl C<stat>,
2135alleviating the need to call the special C<Time::HiRes> functions, which
2136do not act like their perl counterparts.
2137
2138On operating systems or file systems where subsecond time resolution is
2139not supported or could not be detected, a fractional part of C<0> is
2140returned, so it is always safe to call these functions.
2141
2142=over 4
2143
2144=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2145
2146Return the access, modication, change or birth time, respectively,
2147including fractional part. Due to the limited precision of floating point,
2148the accuracy on most platforms is only a bit better than milliseconds
2149for times around now - see the I<nsec> function family, below, for full
2150accuracy.
2151
2152File birth time is only available when the OS and perl support it (on
2153FreeBSD and NetBSD at the time of this writing, although support is
2154adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
2155it). On systems where it isn't available, C<0> is currently returned, but
2156this might change to C<undef> in a future version.
2157
2158=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2159
2160Returns access, modification, change and birth time all in one go, and
2161maybe more times in the future version.
2162
2163=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2164
2165Return the fractional access, modifcation, change or birth time, in nanoseconds,
2166as an integer in the range C<0> to C<999999999>.
2167
2168Note that no accessors are provided for access, modification and
2169change times - you need to get those from C<stat _> if required (C<int
2170IO::AIO::st_atime> and so on will I<not> generally give you the correct
2171value).
2172
2173=item $seconds = IO::AIO::st_btimesec
2174
2175The (integral) seconds part of the file birth time, if available.
2176
2177=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2178
2179Like the functions above, but returns all four times in one go (and maybe
2180more in future versions).
2181
2182=item $counter = IO::AIO::st_gen
2183
2184Returns the generation counter (in practice this is just a random number)
2185of the file. This is only available on platforms which have this member in
2186their C<struct stat> (most BSDs at the time of this writing) and generally
2187only to the root usert. If unsupported, C<0> is returned, but this might
2188change to C<undef> in a future version.
2189
2190=back
2191
2192Example: print the high resolution modification time of F</etc>, using
2193C<stat>, and C<IO::AIO::aio_stat>.
2194
2195 if (stat "/etc") {
2196 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2197 }
2198
2199 IO::AIO::aio_stat "/etc", sub {
2200 $_[0]
2201 and return;
2202
2203 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2204 };
2205
2206 IO::AIO::flush;
2207
2208Output of the awbove on my system, showing reduced and full accuracy:
2209
2210 stat(/etc) mtime: 1534043702.020808
2211 aio_stat(/etc) mtime: 1534043702.020807792
2212
2213
1988=head3 MISCELLANEOUS FUNCTIONS 2214=head3 MISCELLANEOUS FUNCTIONS
1989 2215
1990IO::AIO implements some functions that might be useful, but are not 2216IO::AIO implements some functions that are useful when you want to use
1991asynchronous. 2217some "Advanced I/O" function not available to in Perl, without going the
2218"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2219counterpart.
1992 2220
1993=over 4 2221=over 4
2222
2223=item $numfd = IO::AIO::get_fdlimit
2224
2225This function is I<EXPERIMENTAL> and subject to change.
2226
2227Tries to find the current file descriptor limit and returns it, or
2228C<undef> and sets C<$!> in case of an error. The limit is one larger than
2229the highest valid file descriptor number.
2230
2231=item IO::AIO::min_fdlimit [$numfd]
2232
2233This function is I<EXPERIMENTAL> and subject to change.
2234
2235Try to increase the current file descriptor limit(s) to at least C<$numfd>
2236by changing the soft or hard file descriptor resource limit. If C<$numfd>
2237is missing, it will try to set a very high limit, although this is not
2238recommended when you know the actual minimum that you require.
2239
2240If the limit cannot be raised enough, the function makes a best-effort
2241attempt to increase the limit as much as possible, using various
2242tricks, while still failing. You can query the resulting limit using
2243C<IO::AIO::get_fdlimit>.
2244
2245If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2246true.
1994 2247
1995=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2248=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1996 2249
1997Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2250Calls 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 2251but is blocking (this makes most sense if you know the input data is
… …
2015=item IO::AIO::madvise $scalar, $offset, $len, $advice 2268=item IO::AIO::madvise $scalar, $offset, $len, $advice
2016 2269
2017Simply calls the C<posix_madvise> function (see its 2270Simply calls the C<posix_madvise> function (see its
2018manpage for details). The following advice constants are 2271manpage for details). The following advice constants are
2019available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2272available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2020C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2273C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2274C<IO::AIO::MADV_DONTNEED>.
2275
2276If C<$offset> is negative, counts from the end. If C<$length> is negative,
2277the remaining length of the C<$scalar> is used. If possible, C<$length>
2278will be reduced to fit into the C<$scalar>.
2021 2279
2022On systems that do not implement C<posix_madvise>, this function returns 2280On systems that do not implement C<posix_madvise>, this function returns
2023ENOSYS, otherwise the return value of C<posix_madvise>. 2281ENOSYS, otherwise the return value of C<posix_madvise>.
2024 2282
2025=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2283=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2027Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2285Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2028$scalar (see its manpage for details). The following protect 2286$scalar (see its manpage for details). The following protect
2029constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2287constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2030C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2288C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2031 2289
2290If C<$offset> is negative, counts from the end. If C<$length> is negative,
2291the remaining length of the C<$scalar> is used. If possible, C<$length>
2292will be reduced to fit into the C<$scalar>.
2293
2032On systems that do not implement C<mprotect>, this function returns 2294On systems that do not implement C<mprotect>, this function returns
2033ENOSYS, otherwise the return value of C<mprotect>. 2295ENOSYS, otherwise the return value of C<mprotect>.
2034 2296
2035=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2297=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2036 2298
2037Memory-maps a file (or anonymous memory range) and attaches it to the 2299Memory-maps a file (or anonymous memory range) and attaches it to the
2038given C<$scalar>, which will act like a string scalar. Returns true on 2300given C<$scalar>, which will act like a string scalar. Returns true on
2039success, and false otherwise. 2301success, and false otherwise.
2040 2302
2303The scalar must exist, but its contents do not matter - this means you
2304cannot use a nonexistant array or hash element. When in doubt, C<undef>
2305the scalar first.
2306
2041The only operations allowed on the scalar are C<substr>/C<vec> that don't 2307The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2042change the string length, and most read-only operations such as copying it 2308which don't change the string length, and most read-only operations such
2043or searching it with regexes and so on. 2309as copying it or searching it with regexes and so on.
2044 2310
2045Anything else is unsafe and will, at best, result in memory leaks. 2311Anything else is unsafe and will, at best, result in memory leaks.
2046 2312
2047The memory map associated with the C<$scalar> is automatically removed 2313The memory map associated with the C<$scalar> is automatically removed
2048when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2314when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2049C<IO::AIO::munmap> functions are called. 2315or C<IO::AIO::munmap> functions are called on it.
2050 2316
2051This calls the C<mmap>(2) function internally. See your system's manual 2317This calls the C<mmap>(2) function internally. See your system's manual
2052page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2318page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2053 2319
2054The C<$length> must be larger than zero and smaller than the actual 2320The C<$length> must be larger than zero and smaller than the actual
2055filesize. 2321filesize.
2056 2322
2057C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2323C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2058C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2324C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2059 2325
2060C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2326C<$flags> can be a combination of
2061C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2327C<IO::AIO::MAP_SHARED> or
2062not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2328C<IO::AIO::MAP_PRIVATE>,
2329or a number of system-specific flags (when not available, the are C<0>):
2063(which is set to C<MAP_ANON> if your system only provides this 2330C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2064constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2331C<IO::AIO::MAP_LOCKED>,
2065C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2332C<IO::AIO::MAP_NORESERVE>,
2333C<IO::AIO::MAP_POPULATE>,
2066C<IO::AIO::MAP_NONBLOCK> 2334C<IO::AIO::MAP_NONBLOCK>,
2335C<IO::AIO::MAP_FIXED>,
2336C<IO::AIO::MAP_GROWSDOWN>,
2337C<IO::AIO::MAP_32BIT>,
2338C<IO::AIO::MAP_HUGETLB> or
2339C<IO::AIO::MAP_STACK>.
2067 2340
2068If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2341If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2069 2342
2070C<$offset> is the offset from the start of the file - it generally must be 2343C<$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>. 2344a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2085 2358
2086=item IO::AIO::munmap $scalar 2359=item IO::AIO::munmap $scalar
2087 2360
2088Removes a previous mmap and undefines the C<$scalar>. 2361Removes a previous mmap and undefines the C<$scalar>.
2089 2362
2363=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2364
2365Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2366been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2367C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2368
2369Returns true if successful, and false otherwise. If the underlying mmapped
2370region has changed address, then the true value has the numerical value
2371C<1>, otherwise it has the numerical value C<0>:
2372
2373 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2374 or die "mremap: $!";
2375
2376 if ($success*1) {
2377 warn "scalar has chanegd address in memory\n";
2378 }
2379
2380C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2381implemented, but not supported and might go away in a future version.
2382
2383On systems where this call is not supported or is not emulated, this call
2384returns falls and sets C<$!> to C<ENOSYS>.
2385
2386=item IO::AIO::mlockall $flags
2387
2388Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2389but is blocking.
2390
2090=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2391=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2091 2392
2092Calls the C<munlock> function, undoing the effects of a previous 2393Calls the C<munlock> function, undoing the effects of a previous
2093C<aio_mlock> call (see its description for details). 2394C<aio_mlock> call (see its description for details).
2094 2395
… …
2096 2397
2097Calls the C<munlockall> function. 2398Calls the C<munlockall> function.
2098 2399
2099On systems that do not implement C<munlockall>, this function returns 2400On systems that do not implement C<munlockall>, this function returns
2100ENOSYS, otherwise the return value of C<munlockall>. 2401ENOSYS, otherwise the return value of C<munlockall>.
2402
2403=item $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
2404
2405Uses the GNU/Linux C<accept4(2)> syscall, if available, to accept a socket
2406and return the new file handle on success, or sets C<$!> and returns
2407C<undef> on error.
2408
2409The remote name of the new socket will be stored in C<$sockaddr>, which
2410will be extended to allow for at least C<$sockaddr_maxlen> octets. If the
2411socket name does not fit into C<$sockaddr_maxlen> octets, this is signaled
2412by returning a longer string in C<$sockaddr>, which might or might not be
2413truncated.
2414
2415To accept name-less sockets, use C<undef> for C<$sockaddr> and C<0> for
2416C<$sockaddr_maxlen>.
2417
2418The main reasons to use this syscall rather than portable C«accept(2)>
2419are that you can specify C<SOCK_NONBLOCK> and/or C<SOCK_CLOEXEC>
2420flags and you can accept name-less sockets by specifying C<0> for
2421C<$sockaddr_maxlen>, which is sadly not possible with perl's interface to
2422C<accept>.
2101 2423
2102=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags 2424=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2103 2425
2104Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or 2426Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2105C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they 2427C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
… …
2114 2436
2115See the C<splice(2)> manpage for details. 2437See the C<splice(2)> manpage for details.
2116 2438
2117=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2439=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2118 2440
2119Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2441Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2120description for C<IO::AIO::splice> above for details. 2442description for C<IO::AIO::splice> above for details.
2443
2444=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2445
2446Attempts to query or change the pipe buffer size. Obviously works only
2447on pipes, and currently works only on GNU/Linux systems, and fails with
2448C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2449size on other systems, drop me a note.
2450
2451=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2452
2453This is a direct interface to the Linux L<pipe2(2)> system call. If
2454C<$flags> is missing or C<0>, then this should be the same as a call to
2455perl's built-in C<pipe> function and create a new pipe, and works on
2456systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2457(..., 4096, O_BINARY)>.
2458
2459If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2460the given flags (Linux 2.6.27, glibc 2.9).
2461
2462On success, the read and write file handles are returned.
2463
2464On error, nothing will be returned. If the pipe2 syscall is missing and
2465C<$flags> is non-zero, fails with C<ENOSYS>.
2466
2467Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2468time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2469C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2470
2471Example: create a pipe race-free w.r.t. threads and fork:
2472
2473 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2474 or die "pipe2: $!\n";
2475
2476=item $fh = IO::AIO::memfd_create $pathname[, $flags]
2477
2478This is a direct interface to the Linux L<memfd_create(2)> system
2479call. The (unhelpful) default for C<$flags> is C<0>, but your default
2480should be C<IO::AIO::MFD_CLOEXEC>.
2481
2482On success, the new memfd filehandle is returned, otherwise returns
2483C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
2484
2485Please refer to L<memfd_create(2)> for more info on this call.
2486
2487The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
2488C<IO::AIO::MFD_ALLOW_SEALING> and C<IO::AIO::MFD_HUGETLB>.
2489
2490Example: create a new memfd.
2491
2492 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2493 or die "m,emfd_create: $!\n";
2494=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2495
2496This is a direct interface to the Linux L<eventfd(2)> system call. The
2497(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2498
2499On success, the new eventfd filehandle is returned, otherwise returns
2500C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2501
2502Please refer to L<eventfd(2)> for more info on this call.
2503
2504The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2505C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2506
2507Example: create a new eventfd filehandle:
2508
2509 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2510 or die "eventfd: $!\n";
2511
2512=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2513
2514This is a direct interface to the Linux L<timerfd_create(2)> system
2515call. The (unhelpful) default for C<$flags> is C<0>, but your default
2516should be C<IO::AIO::TFD_CLOEXEC>.
2517
2518On success, the new timerfd filehandle is returned, otherwise returns
2519C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
2520
2521Please refer to L<timerfd_create(2)> for more info on this call.
2522
2523The following C<$clockid> values are
2524available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2525C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2526C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2527C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2528
2529The following C<$flags> values are available (Linux
25302.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2531
2532Example: create a new timerfd and set it to one-second repeated alarms,
2533then wait for two alarms:
2534
2535 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2536 or die "timerfd_create: $!\n";
2537
2538 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2539 or die "timerfd_settime: $!\n";
2540
2541 for (1..2) {
2542 8 == sysread $fh, my $buf, 8
2543 or die "timerfd read failure\n";
2544
2545 printf "number of expirations (likely 1): %d\n",
2546 unpack "Q", $buf;
2547 }
2548
2549=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2550
2551This is a direct interface to the Linux L<timerfd_settime(2)> system
2552call. Please refer to its manpage for more info on this call.
2553
2554The new itimerspec is specified using two (possibly fractional) second
2555values, C<$new_interval> and C<$new_value>).
2556
2557On success, the current interval and value are returned (as per
2558C<timerfd_gettime>). On failure, the empty list is returned.
2559
2560The following C<$flags> values are
2561available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2562C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2563
2564See C<IO::AIO::timerfd_create> for a full example.
2565
2566=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2567
2568This is a direct interface to the Linux L<timerfd_gettime(2)> system
2569call. Please refer to its manpage for more info on this call.
2570
2571On success, returns the current values of interval and value for the given
2572timerfd (as potentially fractional second values). On failure, the empty
2573list is returned.
2121 2574
2122=back 2575=back
2123 2576
2124=cut 2577=cut
2125 2578
… …
2191the process will result in undefined behaviour. Calling it at any time 2644the process will result in undefined behaviour. Calling it at any time
2192will also result in any undefined (by POSIX) behaviour. 2645will also result in any undefined (by POSIX) behaviour.
2193 2646
2194=back 2647=back
2195 2648
2649=head2 LINUX-SPECIFIC CALLS
2650
2651When a call is documented as "linux-specific" then this means it
2652originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2653availability and compatibility of such calls regardless of the platform
2654it is compiled on, so platforms such as FreeBSD which often implement
2655these calls will work. When in doubt, call them and see if they fail wth
2656C<ENOSYS>.
2657
2196=head2 MEMORY USAGE 2658=head2 MEMORY USAGE
2197 2659
2198Per-request usage: 2660Per-request usage:
2199 2661
2200Each aio request uses - depending on your architecture - around 100-200 2662Each aio request uses - depending on your architecture - around 100-200
… …
2212temporary buffers, and each thread requires a stack and other data 2674temporary buffers, and each thread requires a stack and other data
2213structures (usually around 16k-128k, depending on the OS). 2675structures (usually around 16k-128k, depending on the OS).
2214 2676
2215=head1 KNOWN BUGS 2677=head1 KNOWN BUGS
2216 2678
2217Known bugs will be fixed in the next release. 2679Known bugs will be fixed in the next release :)
2680
2681=head1 KNOWN ISSUES
2682
2683Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2684or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2685non-created hash slots or other scalars I didn't think of. It's best to
2686avoid such and either use scalar variables or making sure that the scalar
2687exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2688
2689I am not sure anything can be done about this, so this is considered a
2690known issue, rather than a bug.
2218 2691
2219=head1 SEE ALSO 2692=head1 SEE ALSO
2220 2693
2221L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2694L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2222more natural syntax. 2695more natural syntax and L<IO::FDPass> for file descriptor passing.
2223 2696
2224=head1 AUTHOR 2697=head1 AUTHOR
2225 2698
2226 Marc Lehmann <schmorp@schmorp.de> 2699 Marc Lehmann <schmorp@schmorp.de>
2227 http://home.schmorp.de/ 2700 http://home.schmorp.de/

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