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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.248 by root, Sun Jul 27 22:10:53 2014 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
… …
94 98
95 # file contents now in $contents 99 # file contents now in $contents
96 print $contents; 100 print $contents;
97 101
98 # exit event loop and program 102 # exit event loop and program
99 EV::unloop; 103 EV::break;
100 }; 104 };
101 }; 105 };
102 106
103 # possibly queue up other requests, or open GUI windows, 107 # possibly queue up other requests, or open GUI windows,
104 # check for sockets etc. etc. 108 # check for sockets etc. etc.
105 109
106 # process events as long as there are some: 110 # process events as long as there are some:
107 EV::loop; 111 EV::run;
108 112
109=head1 REQUEST ANATOMY AND LIFETIME 113=head1 REQUEST ANATOMY AND LIFETIME
110 114
111Every 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
112directly visible to Perl. 116directly visible to Perl.
… …
167use common::sense; 171use common::sense;
168 172
169use base 'Exporter'; 173use base 'Exporter';
170 174
171BEGIN { 175BEGIN {
172 our $VERSION = 4.31; 176 our $VERSION = 4.73;
173 177
174 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
175 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
176 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
177 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
178 aio_pathsync aio_readahead aio_fiemap 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
179 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
180 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
181 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
182 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
183 aio_statvfs 187 aio_statvfs
188 aio_slurp
184 aio_wd); 189 aio_wd);
185 190
186 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
187 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
188 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
189 nreqs nready npending nthreads 194 nreqs nready npending nthreads
190 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
191 sendfile fadvise madvise 196 sendfile fadvise madvise
192 mmap munmap munlock munlockall); 197 mmap munmap mremap munlock munlockall);
193 198
194 push @AIO_REQ, qw(aio_busy); # not exported 199 push @AIO_REQ, qw(aio_busy); # not exported
195 200
196 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
197 202
… …
227 aio_unlink $pathname, $callback->($status) 232 aio_unlink $pathname, $callback->($status)
228 aio_mknod $pathname, $mode, $dev, $callback->($status) 233 aio_mknod $pathname, $mode, $dev, $callback->($status)
229 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
230 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
231 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
232 aio_realpath $pathname, $callback->($link) 237 aio_realpath $pathname, $callback->($path)
233 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
234 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
235 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
236 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
237 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
238 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
240 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
241 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
242 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
243 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
244 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)
245 aio_sync $callback->($status) 253 aio_sync $callback->($status)
246 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
247 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
248 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
249 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
250 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
251 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
252 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
253 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
254 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
255 aio_group $callback->(...) 263 aio_group $callback->(...)
256 aio_nop $callback->() 264 aio_nop $callback->()
… …
270 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
271 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
272 IO::AIO::nreqs 280 IO::AIO::nreqs
273 IO::AIO::nready 281 IO::AIO::nready
274 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]
275 287
276 IO::AIO::sendfile $ofh, $ifh, $offset, $count 288 IO::AIO::sendfile $ofh, $ifh, $offset, $count
277 IO::AIO::fadvise $fh, $offset, $len, $advice 289 IO::AIO::fadvise $fh, $offset, $len, $advice
290
278 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 291 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
279 IO::AIO::munmap $scalar 292 IO::AIO::munmap $scalar
293 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
280 IO::AIO::madvise $scalar, $offset, $length, $advice 294 IO::AIO::madvise $scalar, $offset, $length, $advice
281 IO::AIO::mprotect $scalar, $offset, $length, $protect 295 IO::AIO::mprotect $scalar, $offset, $length, $protect
282 IO::AIO::munlock $scalar, $offset = 0, $length = undef 296 IO::AIO::munlock $scalar, $offset = 0, $length = undef
283 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
284 318
285=head2 API NOTES 319=head2 API NOTES
286 320
287All 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
288with 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,
… …
394following POSIX and non-POSIX constants are available (missing ones on 428following POSIX and non-POSIX constants are available (missing ones on
395your system are, as usual, C<0>): 429your system are, as usual, C<0>):
396 430
397C<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>,
398C<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>,
399C<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>.
400 434
401 435
402=item aio_close $fh, $callback->($status) 436=item aio_close $fh, $callback->($status)
403 437
404Asynchronously close a file and call the callback with the result 438Asynchronously close a file and call the callback with the result
… …
439=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 473=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
440 474
441=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 475=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
442 476
443Reads 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
444C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 478C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
445and 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
446error, just like the syscall). 480error, just like the syscall).
447 481
448C<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
449offset plus the actual number of bytes read. 483offset plus the actual number of bytes read.
450 484
… …
508As native sendfile syscalls (as practically any non-POSIX interface hacked 542As native sendfile syscalls (as practically any non-POSIX interface hacked
509together 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
510on many systems, this implementation tries to work around some known bugs 544on many systems, this implementation tries to work around some known bugs
511in Linux and FreeBSD kernels (probably others, too), but that might fail, 545in Linux and FreeBSD kernels (probably others, too), but that might fail,
512so 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> -
513fewre bytes than expected might have been transferred. 547fewer bytes than expected might have been transferred.
514 548
515 549
516=item aio_readahead $fh,$offset,$length, $callback->($retval) 550=item aio_readahead $fh,$offset,$length, $callback->($retval)
517 551
518C<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
… …
522whole 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
523and 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
524(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
525file. The current file offset of the file is left unchanged. 559file. The current file offset of the file is left unchanged.
526 560
527If 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
528emulated by simply reading the data, which would have a similar effect. 562be emulated by simply reading the data, which would have a similar effect.
529 563
530 564
531=item aio_stat $fh_or_path, $callback->($status) 565=item aio_stat $fh_or_path, $callback->($status)
532 566
533=item aio_lstat $fh, $callback->($status) 567=item aio_lstat $fh, $callback->($status)
534 568
535Works 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
536be 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
537or C<-s _> etc... 571using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
572and C<-T>).
538 573
539The 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,
540for an explanation. 575for an explanation.
541 576
542Currently, 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
… …
549behaviour). 584behaviour).
550 585
551C<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>,
552C<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>,
553C<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>.
554 592
555Example: Print the length of F</etc/passwd>: 593Example: Print the length of F</etc/passwd>:
556 594
557 aio_stat "/etc/passwd", sub { 595 aio_stat "/etc/passwd", sub {
558 $_[0] and die "stat failed: $!"; 596 $_[0] and die "stat failed: $!";
… …
602 namemax => 255, 640 namemax => 255,
603 frsize => 1024, 641 frsize => 1024,
604 fsid => 1810 642 fsid => 1810
605 } 643 }
606 644
607Here is a (likely partial - send me updates!) list of fsid values used by
608Linux - it is safe to hardcode these when C<$^O> is C<linux>:
609
610 0x0000adf5 adfs
611 0x0000adff affs
612 0x5346414f afs
613 0x09041934 anon-inode filesystem
614 0x00000187 autofs
615 0x42465331 befs
616 0x1badface bfs
617 0x42494e4d binfmt_misc
618 0x9123683e btrfs
619 0x0027e0eb cgroupfs
620 0xff534d42 cifs
621 0x73757245 coda
622 0x012ff7b7 coh
623 0x28cd3d45 cramfs
624 0x453dcd28 cramfs-wend (wrong endianness)
625 0x64626720 debugfs
626 0x00001373 devfs
627 0x00001cd1 devpts
628 0x0000f15f ecryptfs
629 0x00414a53 efs
630 0x0000137d ext
631 0x0000ef53 ext2/ext3
632 0x0000ef51 ext2
633 0x00004006 fat
634 0x65735546 fuseblk
635 0x65735543 fusectl
636 0x0bad1dea futexfs
637 0x01161970 gfs2
638 0x47504653 gpfs
639 0x00004244 hfs
640 0xf995e849 hpfs
641 0x958458f6 hugetlbfs
642 0x2bad1dea inotifyfs
643 0x00009660 isofs
644 0x000072b6 jffs2
645 0x3153464a jfs
646 0x6b414653 k-afs
647 0x0bd00bd0 lustre
648 0x0000137f minix
649 0x0000138f minix 30 char names
650 0x00002468 minix v2
651 0x00002478 minix v2 30 char names
652 0x00004d5a minix v3
653 0x19800202 mqueue
654 0x00004d44 msdos
655 0x0000564c novell
656 0x00006969 nfs
657 0x6e667364 nfsd
658 0x00003434 nilfs
659 0x5346544e ntfs
660 0x00009fa1 openprom
661 0x7461636F ocfs2
662 0x00009fa0 proc
663 0x6165676c pstorefs
664 0x0000002f qnx4
665 0x858458f6 ramfs
666 0x52654973 reiserfs
667 0x00007275 romfs
668 0x67596969 rpc_pipefs
669 0x73636673 securityfs
670 0xf97cff8c selinux
671 0x0000517b smb
672 0x534f434b sockfs
673 0x73717368 squashfs
674 0x62656572 sysfs
675 0x012ff7b6 sysv2
676 0x012ff7b5 sysv4
677 0x01021994 tmpfs
678 0x15013346 udf
679 0x00011954 ufs
680 0x54190100 ufs byteswapped
681 0x00009fa2 usbdevfs
682 0x01021997 v9fs
683 0xa501fcf5 vxfs
684 0xabba1974 xenfs
685 0x012ff7b4 xenix
686 0x58465342 xfs
687 0x012fd16d xia
688
689=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 645=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
690 646
691Works 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
692and $mtime being undef). Fractional times are supported if the underlying 648and $mtime being undef). Fractional times are supported if the underlying
693syscalls support them. 649syscalls support them.
694 650
695When called with a pathname, uses utimes(2) if available, otherwise 651When called with a pathname, uses utimensat(2) or utimes(2) if available,
696utime(2). If called on a file descriptor, uses futimes(2) if available, 652otherwise utime(2). If called on a file descriptor, uses futimens(2)
697otherwise returns ENOSYS, so this is not portable. 653or futimes(2) if available, otherwise returns ENOSYS, so this is not
654portable.
698 655
699Examples: 656Examples:
700 657
701 # set atime and mtime to current time (basically touch(1)): 658 # set atime and mtime to current time (basically touch(1)):
702 aio_utime "path", undef, undef; 659 aio_utime "path", undef, undef;
… …
722Works like truncate(2) or ftruncate(2). 679Works like truncate(2) or ftruncate(2).
723 680
724 681
725=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 682=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
726 683
727Allocates 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
728linux C<fallocate> docuemntation for details. 685linux C<fallocate> documentation for details.
729 686
730C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 687C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
731to 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>,
732IO::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).
733 695
734The file system block size used by C<fallocate> is presumably the 696The file system block size used by C<fallocate> is presumably the
735C<f_bsize> returned by C<statvfs>. 697C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
698can dictate other limitations.
736 699
737If C<fallocate> isn't available or cannot be emulated (currently no 700If C<fallocate> isn't available or cannot be emulated (currently no
738emulation 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>.
739 702
740 703
… …
799On systems that support the AIO::WD working directory abstraction 762On systems that support the AIO::WD working directory abstraction
800natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead 763natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
801of 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>.
802 765
803 766
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
804=item aio_mkdir $pathname, $mode, $callback->($status) 783=item aio_mkdir $pathname, $mode, $callback->($status)
805 784
806Asynchronously mkdir (create) a directory and call the callback with 785Asynchronously mkdir (create) a directory and call the callback with
807the 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
808request is executed, so do not change your umask. 787request is executed, so do not change your umask.
… …
839 818
840=over 4 819=over 4
841 820
842=item IO::AIO::READDIR_DENTS 821=item IO::AIO::READDIR_DENTS
843 822
844When this flag is off, then the callback gets an arrayref consisting of 823Normally the callback gets an arrayref consisting of names only (as
845names 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
846C<[$name, $type, $inode]> arrayrefs, each describing a single directory 825arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
847entry in more detail. 826single directory entry in more detail:
848 827
849C<$name> is the name of the entry. 828C<$name> is the name of the entry.
850 829
851C<$type> is one of the C<IO::AIO::DT_xxx> constants: 830C<$type> is one of the C<IO::AIO::DT_xxx> constants:
852 831
853C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 832C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
854C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 833C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
855C<IO::AIO::DT_WHT>. 834C<IO::AIO::DT_WHT>.
856 835
857C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 836C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
858know, you have to run stat yourself. Also, for speed reasons, the C<$type> 837to know, you have to run stat yourself. Also, for speed/memory reasons,
859scalars are read-only: you can not modify them. 838the C<$type> scalars are read-only: you must not modify them.
860 839
861C<$inode> is the inode number (which might not be exact on systems with 64 840C<$inode> is the inode number (which might not be exact on systems with 64
862bit inode numbers and 32 bit perls). This field has unspecified content on 841bit inode numbers and 32 bit perls). This field has unspecified content on
863systems that do not deliver the inode information. 842systems that do not deliver the inode information.
864 843
… …
875short names are tried first. 854short names are tried first.
876 855
877=item IO::AIO::READDIR_STAT_ORDER 856=item IO::AIO::READDIR_STAT_ORDER
878 857
879When this flag is set, then the names will be returned in an order 858When this flag is set, then the names will be returned in an order
880suitable for stat()'ing each one. That is, when you plan to stat() 859suitable for stat()'ing each one. That is, when you plan to stat() most or
881all files in the given directory, then the returned order will likely 860all files in the given directory, then the returned order will likely be
882be fastest. 861faster.
883 862
884If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 863If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
885the likely dirs come first, resulting in a less optimal stat order. 864then the likely dirs come first, resulting in a less optimal stat order
865for stat'ing all entries, but likely a more optimal order for finding
866subdirectories.
886 867
887=item IO::AIO::READDIR_FOUND_UNKNOWN 868=item IO::AIO::READDIR_FOUND_UNKNOWN
888 869
889This flag should not be set when calling C<aio_readdirx>. Instead, it 870This flag should not be set when calling C<aio_readdirx>. Instead, it
890is being set by C<aio_readdirx>, when any of the C<$type>'s found were 871is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
892C<$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.
893 874
894=back 875=back
895 876
896 877
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
897=item aio_load $pathname, $data, $callback->($status) 907=item aio_load $pathname, $data, $callback->($status)
898 908
899This 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
900memory. 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.
901 913
902=cut 914=cut
903 915
904sub aio_load($$;$) { 916sub aio_load($$;$) {
905 my ($path, undef, $cb) = @_; 917 my ($path, undef, $cb) = @_;
… …
925=item aio_copy $srcpath, $dstpath, $callback->($status) 937=item aio_copy $srcpath, $dstpath, $callback->($status)
926 938
927Try 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
928destination) from C<$srcpath> to C<$dstpath> and call the callback with 940destination) from C<$srcpath> to C<$dstpath> and call the callback with
929a 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.
930 944
931This is a composite request that creates the destination file with 945This is a composite request that creates the destination file with
932mode 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
933C<aio_sendfile>, followed by restoring atime, mtime, access mode and 947C<aio_sendfile>, followed by restoring atime, mtime, access mode and
934uid/gid, in that order. 948uid/gid, in that order.
… …
1044Scans a directory (similar to C<aio_readdir>) but additionally tries to 1058Scans a directory (similar to C<aio_readdir>) but additionally tries to
1045efficiently separate the entries of directory C<$path> into two sets of 1059efficiently separate the entries of directory C<$path> into two sets of
1046names, directories you can recurse into (directories), and ones you cannot 1060names, directories you can recurse into (directories), and ones you cannot
1047recurse into (everything else, including symlinks to directories). 1061recurse into (everything else, including symlinks to directories).
1048 1062
1049C<aio_scandir> is a composite request that creates of many sub requests_ 1063C<aio_scandir> is a composite request that generates many sub requests.
1050C<$maxreq> specifies the maximum number of outstanding aio requests that 1064C<$maxreq> specifies the maximum number of outstanding aio requests that
1051this function generates. If it is C<< <= 0 >>, then a suitable default 1065this function generates. If it is C<< <= 0 >>, then a suitable default
1052will be chosen (currently 4). 1066will be chosen (currently 4).
1053 1067
1054On error, the callback is called without arguments, otherwise it receives 1068On error, the callback is called without arguments, otherwise it receives
… …
1118 aioreq_pri $pri; 1132 aioreq_pri $pri;
1119 add $grp aio_stat $wd, sub { 1133 add $grp aio_stat $wd, sub {
1120 return $grp->result () if $_[0]; 1134 return $grp->result () if $_[0];
1121 my $now = time; 1135 my $now = time;
1122 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 }
1123 1145
1124 # read the directory entries 1146 # read the directory entries
1125 aioreq_pri $pri; 1147 aioreq_pri $pri;
1126 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1148 add $grp aio_readdirx $wd, $rdxflags, sub {
1127 my $entries = shift 1149 my ($entries, $flags) = @_
1128 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 }
1129 1199
1130 # stat the dir another time 1200 # stat the dir another time
1131 aioreq_pri $pri; 1201 aioreq_pri $pri;
1132 add $grp aio_stat $wd, sub { 1202 add $grp aio_stat $wd, sub {
1133 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1203 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1220 }; 1290 };
1221 1291
1222 $grp 1292 $grp
1223} 1293}
1224 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
1225=item aio_sync $callback->($status) 1343=item aio_sync $callback->($status)
1226 1344
1227Asynchronously call sync and call the callback when finished. 1345Asynchronously call sync and call the callback when finished.
1228 1346
1229=item aio_fsync $fh, $callback->($status) 1347=item aio_fsync $fh, $callback->($status)
… …
1297 }; 1415 };
1298 1416
1299 $grp 1417 $grp
1300} 1418}
1301 1419
1302=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)
1303 1421
1304This 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
1305scalars (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
1306scalars 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
1307scalar 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
… …
1309 1427
1310It 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
1311area 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
1312later. 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>
1313is 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
1314a 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
1315C<IO::AIO::MS_SYNC>. 1433C<IO::AIO::MS_INVALIDATE>.
1316 1434
1317=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)
1318 1436
1319This 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
1320scalars. 1438scalars.
… …
1350 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;
1351 aio_mlock $data; # mlock in background 1469 aio_mlock $data; # mlock in background
1352 1470
1353=item aio_mlockall $flags, $callback->($status) 1471=item aio_mlockall $flags, $callback->($status)
1354 1472
1355Calls the C<mlockall> function with the given C<$flags> (a combination of 1473Calls the C<mlockall> function with the given C<$flags> (a
1356C<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>).
1357 1476
1358On 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>
1359and 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>.
1360 1481
1361Note that the corresponding C<munlockall> is synchronous and is 1482Note that the corresponding C<munlockall> is synchronous and is
1362documented under L<MISCELLANEOUS FUNCTIONS>. 1483documented under L<MISCELLANEOUS FUNCTIONS>.
1363 1484
1364Example: asynchronously lock all current and future pages into memory. 1485Example: asynchronously lock all current and future pages into memory.
… …
1403C<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>,
1404C<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>,
1405C<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
1406C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1527C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1407 1528
1408At 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
1409C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1530C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1410it 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
1411extents. 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>.
1412 1534
1413=item aio_group $callback->(...) 1535=item aio_group $callback->(...)
1414 1536
1415This is a very special aio request: Instead of doing something, it is a 1537This is a very special aio request: Instead of doing something, it is a
1416container for other aio requests, which is useful if you want to bundle 1538container for other aio requests, which is useful if you want to bundle
… …
1500 aio_stat [$etcdir, "passwd"], sub { 1622 aio_stat [$etcdir, "passwd"], sub {
1501 # yay 1623 # yay
1502 }; 1624 };
1503 }; 1625 };
1504 1626
1505That 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
1506an IO::AIO::WD object is itself a potentially blocking operation, which is 1628creating an IO::AIO::WD object is itself a potentially blocking operation,
1507why it is done asynchronously. 1629which is why it is done asynchronously.
1508 1630
1509To 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
1510either of the following three request calls: 1632either of the following three request calls:
1511 1633
1512 aio_lstat "/etc" , sub { ... # pathname as normal string 1634 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1529There are some caveats: when directories get renamed (or deleted), the 1651There are some caveats: when directories get renamed (or deleted), the
1530pathname 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
1531nowhere at all), while the directory fd, if available on the system, 1653nowhere at all), while the directory fd, if available on the system,
1532will still point to the original directory. Most functions accepting a 1654will still point to the original directory. Most functions accepting a
1533pathname 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
1534older systems. Some functions (such as realpath) will always rely on the 1656older systems. Some functions (such as C<aio_realpath>) will always rely on
1535string form of the pathname. 1657the string form of the pathname.
1536 1658
1537So this functionality is mainly useful to get some protection against 1659So this functionality is mainly useful to get some protection against
1538C<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
1539reference, and to speed up doing many operations in the same directory 1661reference, and to speed up doing many operations in the same directory
1540(e.g. when stat'ing all files in a directory). 1662(e.g. when stat'ing all files in a directory).
… …
1557C<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
1558expected way. 1680expected way.
1559 1681
1560=item IO::AIO::CWD 1682=item IO::AIO::CWD
1561 1683
1562This is a compiletime constant (object) that represents the process 1684This is a compile time constant (object) that represents the process
1563current working directory. 1685current working directory.
1564 1686
1565Specifying 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
1566the pathname would be specified directly, without a directory object. For 1688the pathname would be specified directly, without a directory object. For
1567example, these calls are functionally identical: 1689example, these calls are functionally identical:
… …
1748The 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
1749automatically bumps it up to C<2>. 1871automatically bumps it up to C<2>.
1750 1872
1751=back 1873=back
1752 1874
1875
1753=head2 SUPPORT FUNCTIONS 1876=head2 SUPPORT FUNCTIONS
1754 1877
1755=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1878=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1756 1879
1757=over 4 1880=over 4
… …
1822Strictly equivalent to: 1945Strictly equivalent to:
1823 1946
1824 IO::AIO::poll_wait, IO::AIO::poll_cb 1947 IO::AIO::poll_wait, IO::AIO::poll_cb
1825 while IO::AIO::nreqs; 1948 while IO::AIO::nreqs;
1826 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
1827=item IO::AIO::max_poll_reqs $nreqs 1960=item IO::AIO::max_poll_reqs $nreqs
1828 1961
1829=item IO::AIO::max_poll_time $seconds 1962=item IO::AIO::max_poll_time $seconds
1830 1963
1831These set the maximum number of requests (default C<0>, meaning infinity) 1964These set the maximum number of requests (default C<0>, meaning infinity)
… …
1857 poll => 'r', nice => 1, 1990 poll => 'r', nice => 1,
1858 cb => &IO::AIO::poll_cb); 1991 cb => &IO::AIO::poll_cb);
1859 1992
1860=back 1993=back
1861 1994
1995
1862=head3 CONTROLLING THE NUMBER OF THREADS 1996=head3 CONTROLLING THE NUMBER OF THREADS
1863 1997
1864=over 1998=over
1865 1999
1866=item IO::AIO::min_parallel $nthreads 2000=item IO::AIO::min_parallel $nthreads
… …
1932This 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
1933blocks, 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
1934use an C<aio_group> together with a feed callback. 2068use an C<aio_group> together with a feed callback.
1935 2069
1936Its 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
1937a lot of files, you can write somehting like this: 2071a lot of files, you can write something like this:
1938 2072
1939 IO::AIO::max_outstanding 32; 2073 IO::AIO::max_outstanding 32;
1940 2074
1941 for my $path (...) { 2075 for my $path (...) {
1942 aio_stat $path , ...; 2076 aio_stat $path , ...;
… …
1953The 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
1954practical limit on the number of outstanding requests. 2088practical limit on the number of outstanding requests.
1955 2089
1956=back 2090=back
1957 2091
2092
1958=head3 STATISTICAL INFORMATION 2093=head3 STATISTICAL INFORMATION
1959 2094
1960=over 2095=over
1961 2096
1962=item IO::AIO::nreqs 2097=item IO::AIO::nreqs
… …
1978 2113
1979Returns the number of requests currently in the pending state (executed, 2114Returns the number of requests currently in the pending state (executed,
1980but not yet processed by poll_cb). 2115but not yet processed by poll_cb).
1981 2116
1982=back 2117=back
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
1983 2213
1984=head3 MISCELLANEOUS FUNCTIONS 2214=head3 MISCELLANEOUS FUNCTIONS
1985 2215
1986IO::AIO implements some functions that are useful when you want to use 2216IO::AIO implements some functions that are useful when you want to use
1987some "Advanced I/O" function not available to in Perl, without going the 2217some "Advanced I/O" function not available to in Perl, without going the
1988"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*> 2218"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
1989counterpart. 2219counterpart.
1990 2220
1991=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.
1992 2247
1993=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2248=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1994 2249
1995Calls 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>,
1996but 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
… …
2013=item IO::AIO::madvise $scalar, $offset, $len, $advice 2268=item IO::AIO::madvise $scalar, $offset, $len, $advice
2014 2269
2015Simply calls the C<posix_madvise> function (see its 2270Simply calls the C<posix_madvise> function (see its
2016manpage for details). The following advice constants are 2271manpage for details). The following advice constants are
2017available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2272available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2018C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2273C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2274C<IO::AIO::MADV_DONTNEED>.
2275
2276If C<$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>.
2019 2279
2020On systems that do not implement C<posix_madvise>, this function returns 2280On systems that do not implement C<posix_madvise>, this function returns
2021ENOSYS, otherwise the return value of C<posix_madvise>. 2281ENOSYS, otherwise the return value of C<posix_madvise>.
2022 2282
2023=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2283=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2025Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2285Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2026$scalar (see its manpage for details). The following protect 2286$scalar (see its manpage for details). The following protect
2027constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2287constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2028C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2288C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2029 2289
2290If C<$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
2030On systems that do not implement C<mprotect>, this function returns 2294On systems that do not implement C<mprotect>, this function returns
2031ENOSYS, otherwise the return value of C<mprotect>. 2295ENOSYS, otherwise the return value of C<mprotect>.
2032 2296
2033=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2297=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2034 2298
2035Memory-maps a file (or anonymous memory range) and attaches it to the 2299Memory-maps a file (or anonymous memory range) and attaches it to the
2036given C<$scalar>, which will act like a string scalar. Returns true on 2300given C<$scalar>, which will act like a string scalar. Returns true on
2037success, and false otherwise. 2301success, and false otherwise.
2038 2302
2303The scalar must exist, but its contents do not matter - this means you
2304cannot use a nonexistant array or hash element. When in doubt, C<undef>
2305the scalar first.
2306
2039The only operations allowed on the scalar are C<substr>/C<vec> that don't 2307The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2040change the string length, and most read-only operations such as copying it 2308which don't change the string length, and most read-only operations such
2041or searching it with regexes and so on. 2309as copying it or searching it with regexes and so on.
2042 2310
2043Anything else is unsafe and will, at best, result in memory leaks. 2311Anything else is unsafe and will, at best, result in memory leaks.
2044 2312
2045The memory map associated with the C<$scalar> is automatically removed 2313The memory map associated with the C<$scalar> is automatically removed
2046when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2314when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2047C<IO::AIO::munmap> functions are called. 2315or C<IO::AIO::munmap> functions are called on it.
2048 2316
2049This calls the C<mmap>(2) function internally. See your system's manual 2317This calls the C<mmap>(2) function internally. See your system's manual
2050page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2318page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2051 2319
2052The C<$length> must be larger than zero and smaller than the actual 2320The C<$length> must be larger than zero and smaller than the actual
2053filesize. 2321filesize.
2054 2322
2055C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2323C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2056C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2324C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2057 2325
2058C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2326C<$flags> can be a combination of
2059C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2327C<IO::AIO::MAP_SHARED> or
2060not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2328C<IO::AIO::MAP_PRIVATE>,
2329or a number of system-specific flags (when not available, the are C<0>):
2061(which is set to C<MAP_ANON> if your system only provides this 2330C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2062constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2331C<IO::AIO::MAP_LOCKED>,
2063C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2332C<IO::AIO::MAP_NORESERVE>,
2333C<IO::AIO::MAP_POPULATE>,
2064C<IO::AIO::MAP_NONBLOCK> 2334C<IO::AIO::MAP_NONBLOCK>,
2335C<IO::AIO::MAP_FIXED>,
2336C<IO::AIO::MAP_GROWSDOWN>,
2337C<IO::AIO::MAP_32BIT>,
2338C<IO::AIO::MAP_HUGETLB> or
2339C<IO::AIO::MAP_STACK>.
2065 2340
2066If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2341If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2067 2342
2068C<$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
2069a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2344a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2083 2358
2084=item IO::AIO::munmap $scalar 2359=item IO::AIO::munmap $scalar
2085 2360
2086Removes a previous mmap and undefines the C<$scalar>. 2361Removes a previous mmap and undefines the C<$scalar>.
2087 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
2088=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2391=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2089 2392
2090Calls the C<munlock> function, undoing the effects of a previous 2393Calls the C<munlock> function, undoing the effects of a previous
2091C<aio_mlock> call (see its description for details). 2394C<aio_mlock> call (see its description for details).
2092 2395
… …
2094 2397
2095Calls the C<munlockall> function. 2398Calls the C<munlockall> function.
2096 2399
2097On systems that do not implement C<munlockall>, this function returns 2400On systems that do not implement C<munlockall>, this function returns
2098ENOSYS, 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>.
2099 2423
2100=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, $flags
2101 2425
2102Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or 2426Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2103C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they 2427C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
… …
2121 2445
2122Attempts to query or change the pipe buffer size. Obviously works only 2446Attempts to query or change the pipe buffer size. Obviously works only
2123on pipes, and currently works only on GNU/Linux systems, and fails with 2447on pipes, and currently works only on GNU/Linux systems, and fails with
2124C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer 2448C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2125size on other systems, drop me a note. 2449size on other systems, drop me a note.
2450
2451=item ($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.
2126 2574
2127=back 2575=back
2128 2576
2129=cut 2577=cut
2130 2578
… …
2196the process will result in undefined behaviour. Calling it at any time 2644the process will result in undefined behaviour. Calling it at any time
2197will also result in any undefined (by POSIX) behaviour. 2645will also result in any undefined (by POSIX) behaviour.
2198 2646
2199=back 2647=back
2200 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
2201=head2 MEMORY USAGE 2658=head2 MEMORY USAGE
2202 2659
2203Per-request usage: 2660Per-request usage:
2204 2661
2205Each aio request uses - depending on your architecture - around 100-200 2662Each aio request uses - depending on your architecture - around 100-200
… …
2217temporary buffers, and each thread requires a stack and other data 2674temporary buffers, and each thread requires a stack and other data
2218structures (usually around 16k-128k, depending on the OS). 2675structures (usually around 16k-128k, depending on the OS).
2219 2676
2220=head1 KNOWN BUGS 2677=head1 KNOWN BUGS
2221 2678
2222Known 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.
2223 2691
2224=head1 SEE ALSO 2692=head1 SEE ALSO
2225 2693
2226L<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
2227more natural syntax. 2695more natural syntax and L<IO::FDPass> for file descriptor passing.
2228 2696
2229=head1 AUTHOR 2697=head1 AUTHOR
2230 2698
2231 Marc Lehmann <schmorp@schmorp.de> 2699 Marc Lehmann <schmorp@schmorp.de>
2232 http://home.schmorp.de/ 2700 http://home.schmorp.de/

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