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Revision 1.57 by root, Mon Jan 18 11:53:09 2016 UTC vs.
Revision 1.69 by root, Tue Sep 6 10:56:12 2022 UTC

1NAME 1NAME
2 IO::AIO - Asynchronous Input/Output 2 IO::AIO - Asynchronous/Advanced Input/Output
3 3
4SYNOPSIS 4SYNOPSIS
5 use IO::AIO; 5 use IO::AIO;
6 6
7 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { 7 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
… …
54 functions available on many operating systems. However, they are often 54 functions available on many operating systems. However, they are often
55 not well-supported or restricted (GNU/Linux doesn't allow them on normal 55 not well-supported or restricted (GNU/Linux doesn't allow them on normal
56 files currently, for example), and they would only support aio_read and 56 files currently, for example), and they would only support aio_read and
57 aio_write, so the remaining functionality would have to be implemented 57 aio_write, so the remaining functionality would have to be implemented
58 using threads anyway. 58 using threads anyway.
59
60 In addition to asynchronous I/O, this module also exports some rather
61 arcane interfaces, such as "madvise" or linux's "splice" system call,
62 which is why the "A" in "AIO" can also mean *advanced*.
59 63
60 Although the module will work in the presence of other (Perl-) threads, 64 Although the module will work in the presence of other (Perl-) threads,
61 it is currently not reentrant in any way, so use appropriate locking 65 it is currently not reentrant in any way, so use appropriate locking
62 yourself, always call "poll_cb" from within the same thread, or never 66 yourself, always call "poll_cb" from within the same thread, or never
63 call "poll_cb" (or other "aio_" functions) recursively. 67 call "poll_cb" (or other "aio_" functions) recursively.
… …
173 aio_link $srcpath, $dstpath, $callback->($status) 177 aio_link $srcpath, $dstpath, $callback->($status)
174 aio_symlink $srcpath, $dstpath, $callback->($status) 178 aio_symlink $srcpath, $dstpath, $callback->($status)
175 aio_readlink $pathname, $callback->($link) 179 aio_readlink $pathname, $callback->($link)
176 aio_realpath $pathname, $callback->($path) 180 aio_realpath $pathname, $callback->($path)
177 aio_rename $srcpath, $dstpath, $callback->($status) 181 aio_rename $srcpath, $dstpath, $callback->($status)
182 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
178 aio_mkdir $pathname, $mode, $callback->($status) 183 aio_mkdir $pathname, $mode, $callback->($status)
179 aio_rmdir $pathname, $callback->($status) 184 aio_rmdir $pathname, $callback->($status)
180 aio_readdir $pathname, $callback->($entries) 185 aio_readdir $pathname, $callback->($entries)
181 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 186 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
182 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 187 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
184 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 189 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
185 aio_load $pathname, $data, $callback->($status) 190 aio_load $pathname, $data, $callback->($status)
186 aio_copy $srcpath, $dstpath, $callback->($status) 191 aio_copy $srcpath, $dstpath, $callback->($status)
187 aio_move $srcpath, $dstpath, $callback->($status) 192 aio_move $srcpath, $dstpath, $callback->($status)
188 aio_rmtree $pathname, $callback->($status) 193 aio_rmtree $pathname, $callback->($status)
194 aio_fcntl $fh, $cmd, $arg, $callback->($status)
195 aio_ioctl $fh, $request, $buf, $callback->($status)
189 aio_sync $callback->($status) 196 aio_sync $callback->($status)
190 aio_syncfs $fh, $callback->($status) 197 aio_syncfs $fh, $callback->($status)
191 aio_fsync $fh, $callback->($status) 198 aio_fsync $fh, $callback->($status)
192 aio_fdatasync $fh, $callback->($status) 199 aio_fdatasync $fh, $callback->($status)
193 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 200 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
194 aio_pathsync $pathname, $callback->($status) 201 aio_pathsync $pathname, $callback->($status)
195 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 202 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
196 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 203 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
197 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 204 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
198 aio_mlockall $flags, $callback->($status) 205 aio_mlockall $flags, $callback->($status)
199 aio_group $callback->(...) 206 aio_group $callback->(...)
200 aio_nop $callback->() 207 aio_nop $callback->()
… …
214 IO::AIO::idle_timeout $seconds 221 IO::AIO::idle_timeout $seconds
215 IO::AIO::max_outstanding $maxreqs 222 IO::AIO::max_outstanding $maxreqs
216 IO::AIO::nreqs 223 IO::AIO::nreqs
217 IO::AIO::nready 224 IO::AIO::nready
218 IO::AIO::npending 225 IO::AIO::npending
226 IO::AIO::reinit
227
228 $nfd = IO::AIO::get_fdlimit
229 IO::AIO::min_fdlimit $nfd
219 230
220 IO::AIO::sendfile $ofh, $ifh, $offset, $count 231 IO::AIO::sendfile $ofh, $ifh, $offset, $count
221 IO::AIO::fadvise $fh, $offset, $len, $advice 232 IO::AIO::fadvise $fh, $offset, $len, $advice
233 IO::AIO::fexecve $fh, $argv, $envp
234
222 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 235 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
223 IO::AIO::munmap $scalar 236 IO::AIO::munmap $scalar
237 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
224 IO::AIO::madvise $scalar, $offset, $length, $advice 238 IO::AIO::madvise $scalar, $offset, $length, $advice
225 IO::AIO::mprotect $scalar, $offset, $length, $protect 239 IO::AIO::mprotect $scalar, $offset, $length, $protect
226 IO::AIO::munlock $scalar, $offset = 0, $length = undef 240 IO::AIO::munlock $scalar, $offset = 0, $length = undef
227 IO::AIO::munlockall 241 IO::AIO::munlockall
242
243 # stat extensions
244 $counter = IO::AIO::st_gen
245 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
246 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
247 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
248 $seconds = IO::AIO::st_btimesec
249 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
250
251 # very much unportable syscalls
252 IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
253 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
254 IO::AIO::tee $r_fh, $w_fh, $length, $flags
255
256 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
257 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
258
259 $fh = IO::AIO::eventfd [$initval, [$flags]]
260 $fh = IO::AIO::memfd_create $pathname[, $flags]
261
262 $fh = IO::AIO::timerfd_create $clockid[, $flags]
263 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
264 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
265
266 $fh = IO::AIO::pidfd_open $pid[, $flags]
267 $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
268 $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
269
270 $retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data = undef
271 $retval = IO::AIO::umount $path, $flags = 0
228 272
229 API NOTES 273 API NOTES
230 All the "aio_*" calls are more or less thin wrappers around the syscall 274 All the "aio_*" calls are more or less thin wrappers around the syscall
231 with the same name (sans "aio_"). The arguments are similar or 275 with the same name (sans "aio_"). The arguments are similar or
232 identical, and they all accept an additional (and optional) $callback 276 identical, and they all accept an additional (and optional) $callback
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330 "O_APPEND"), the following POSIX and non-POSIX constants are 374 "O_APPEND"), the following POSIX and non-POSIX constants are
331 available (missing ones on your system are, as usual, 0): 375 available (missing ones on your system are, as usual, 0):
332 376
333 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 377 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
334 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 378 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
335 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", and 379 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", "O_TTY_INIT"
336 "O_TTY_INIT". 380 and "O_ACCMODE".
337 381
338 aio_close $fh, $callback->($status) 382 aio_close $fh, $callback->($status)
339 Asynchronously close a file and call the callback with the result 383 Asynchronously close a file and call the callback with the result
340 code. 384 code.
341 385
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371 415
372 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 416 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
373 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 417 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
374 Reads or writes $length bytes from or to the specified $fh and 418 Reads or writes $length bytes from or to the specified $fh and
375 $offset into the scalar given by $data and offset $dataoffset and 419 $offset into the scalar given by $data and offset $dataoffset and
376 calls the callback without the actual number of bytes read (or -1 on 420 calls the callback with the actual number of bytes transferred (or
377 error, just like the syscall). 421 -1 on error, just like the syscall).
378 422
379 "aio_read" will, like "sysread", shrink or grow the $data scalar to 423 "aio_read" will, like "sysread", shrink or grow the $data scalar to
380 offset plus the actual number of bytes read. 424 offset plus the actual number of bytes read.
381 425
382 If $offset is undefined, then the current file descriptor offset 426 If $offset is undefined, then the current file descriptor offset
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439 As native sendfile syscalls (as practically any non-POSIX interface 483 As native sendfile syscalls (as practically any non-POSIX interface
440 hacked together in a hurry to improve benchmark numbers) tend to be 484 hacked together in a hurry to improve benchmark numbers) tend to be
441 rather buggy on many systems, this implementation tries to work 485 rather buggy on many systems, this implementation tries to work
442 around some known bugs in Linux and FreeBSD kernels (probably 486 around some known bugs in Linux and FreeBSD kernels (probably
443 others, too), but that might fail, so you really really should check 487 others, too), but that might fail, so you really really should check
444 the return value of "aio_sendfile" - fewre bytes than expected might 488 the return value of "aio_sendfile" - fewer bytes than expected might
445 have been transferred. 489 have been transferred.
446 490
447 aio_readahead $fh,$offset,$length, $callback->($retval) 491 aio_readahead $fh,$offset,$length, $callback->($retval)
448 "aio_readahead" populates the page cache with data from a file so 492 "aio_readahead" populates the page cache with data from a file so
449 that subsequent reads from that file will not block on disk I/O. The 493 that subsequent reads from that file will not block on disk I/O. The
… …
453 to a page boundary and bytes are read up to the next page boundary 497 to a page boundary and bytes are read up to the next page boundary
454 greater than or equal to (off-set+length). "aio_readahead" does not 498 greater than or equal to (off-set+length). "aio_readahead" does not
455 read beyond the end of the file. The current file offset of the file 499 read beyond the end of the file. The current file offset of the file
456 is left unchanged. 500 is left unchanged.
457 501
458 If that syscall doesn't exist (likely if your OS isn't Linux) it 502 If that syscall doesn't exist (likely if your kernel isn't Linux) it
459 will be emulated by simply reading the data, which would have a 503 will be emulated by simply reading the data, which would have a
460 similar effect. 504 similar effect.
461 505
462 aio_stat $fh_or_path, $callback->($status) 506 aio_stat $fh_or_path, $callback->($status)
463 aio_lstat $fh, $callback->($status) 507 aio_lstat $fh, $callback->($status)
464 Works like perl's "stat" or "lstat" in void context. The callback 508 Works almost exactly like perl's "stat" or "lstat" in void context.
465 will be called after the stat and the results will be available 509 The callback will be called after the stat and the results will be
466 using "stat _" or "-s _" etc... 510 available using "stat _" or "-s _" and other tests (with the
511 exception of "-B" and "-T").
467 512
468 The pathname passed to "aio_stat" must be absolute. See API NOTES, 513 The pathname passed to "aio_stat" must be absolute. See API NOTES,
469 above, for an explanation. 514 above, for an explanation.
470 515
471 Currently, the stats are always 64-bit-stats, i.e. instead of 516 Currently, the stats are always 64-bit-stats, i.e. instead of
… …
479 back on traditional behaviour). 524 back on traditional behaviour).
480 525
481 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", 526 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
482 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", 527 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
483 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". 528 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
529
530 To access higher resolution stat timestamps, see "SUBSECOND STAT
531 TIME ACCESS".
484 532
485 Example: Print the length of /etc/passwd: 533 Example: Print the length of /etc/passwd:
486 534
487 aio_stat "/etc/passwd", sub { 535 aio_stat "/etc/passwd", sub {
488 $_[0] and die "stat failed: $!"; 536 $_[0] and die "stat failed: $!";
… …
530 namemax => 255, 578 namemax => 255,
531 frsize => 1024, 579 frsize => 1024,
532 fsid => 1810 580 fsid => 1810
533 } 581 }
534 582
535 Here is a (likely partial - send me updates!) list of fsid values
536 used by Linux - it is safe to hardcode these when $^O is "linux":
537
538 0x0000adf5 adfs
539 0x0000adff affs
540 0x5346414f afs
541 0x09041934 anon-inode filesystem
542 0x00000187 autofs
543 0x42465331 befs
544 0x1badface bfs
545 0x42494e4d binfmt_misc
546 0x9123683e btrfs
547 0x0027e0eb cgroupfs
548 0xff534d42 cifs
549 0x73757245 coda
550 0x012ff7b7 coh
551 0x28cd3d45 cramfs
552 0x453dcd28 cramfs-wend (wrong endianness)
553 0x64626720 debugfs
554 0x00001373 devfs
555 0x00001cd1 devpts
556 0x0000f15f ecryptfs
557 0x00414a53 efs
558 0x0000137d ext
559 0x0000ef53 ext2/ext3/ext4
560 0x0000ef51 ext2
561 0xf2f52010 f2fs
562 0x00004006 fat
563 0x65735546 fuseblk
564 0x65735543 fusectl
565 0x0bad1dea futexfs
566 0x01161970 gfs2
567 0x47504653 gpfs
568 0x00004244 hfs
569 0xf995e849 hpfs
570 0x00c0ffee hostfs
571 0x958458f6 hugetlbfs
572 0x2bad1dea inotifyfs
573 0x00009660 isofs
574 0x000072b6 jffs2
575 0x3153464a jfs
576 0x6b414653 k-afs
577 0x0bd00bd0 lustre
578 0x0000137f minix
579 0x0000138f minix 30 char names
580 0x00002468 minix v2
581 0x00002478 minix v2 30 char names
582 0x00004d5a minix v3
583 0x19800202 mqueue
584 0x00004d44 msdos
585 0x0000564c novell
586 0x00006969 nfs
587 0x6e667364 nfsd
588 0x00003434 nilfs
589 0x5346544e ntfs
590 0x00009fa1 openprom
591 0x7461636F ocfs2
592 0x00009fa0 proc
593 0x6165676c pstorefs
594 0x0000002f qnx4
595 0x68191122 qnx6
596 0x858458f6 ramfs
597 0x52654973 reiserfs
598 0x00007275 romfs
599 0x67596969 rpc_pipefs
600 0x73636673 securityfs
601 0xf97cff8c selinux
602 0x0000517b smb
603 0x534f434b sockfs
604 0x73717368 squashfs
605 0x62656572 sysfs
606 0x012ff7b6 sysv2
607 0x012ff7b5 sysv4
608 0x01021994 tmpfs
609 0x15013346 udf
610 0x00011954 ufs
611 0x54190100 ufs byteswapped
612 0x00009fa2 usbdevfs
613 0x01021997 v9fs
614 0xa501fcf5 vxfs
615 0xabba1974 xenfs
616 0x012ff7b4 xenix
617 0x58465342 xfs
618 0x012fd16d xia
619
620 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 583 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
621 Works like perl's "utime" function (including the special case of 584 Works like perl's "utime" function (including the special case of
622 $atime and $mtime being undef). Fractional times are supported if 585 $atime and $mtime being undef). Fractional times are supported if
623 the underlying syscalls support them. 586 the underlying syscalls support them.
624 587
625 When called with a pathname, uses utimes(2) if available, otherwise 588 When called with a pathname, uses utimensat(2) or utimes(2) if
626 utime(2). If called on a file descriptor, uses futimes(2) if 589 available, otherwise utime(2). If called on a file descriptor, uses
627 available, otherwise returns ENOSYS, so this is not portable. 590 futimens(2) or futimes(2) if available, otherwise returns ENOSYS, so
591 this is not portable.
628 592
629 Examples: 593 Examples:
630 594
631 # set atime and mtime to current time (basically touch(1)): 595 # set atime and mtime to current time (basically touch(1)):
632 aio_utime "path", undef, undef; 596 aio_utime "path", undef, undef;
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655 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate 619 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
656 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE | 620 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
657 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range. 621 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
658 622
659 IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range 623 IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range
660 (without leaving a hole) and "FALLOC_FL_ZERO_RANGE", to zero a range 624 (without leaving a hole), "FALLOC_FL_ZERO_RANGE", to zero a range,
625 "FALLOC_FL_INSERT_RANGE" to insert a range and
626 "FALLOC_FL_UNSHARE_RANGE" to unshare shared blocks (see your
661 (see your fallocate(2) manpage). 627 fallocate(2) manpage).
662 628
663 The file system block size used by "fallocate" is presumably the 629 The file system block size used by "fallocate" is presumably the
664 "f_bsize" returned by "statvfs". 630 "f_bsize" returned by "statvfs", but different filesystems and
631 filetypes can dictate other limitations.
665 632
666 If "fallocate" isn't available or cannot be emulated (currently no 633 If "fallocate" isn't available or cannot be emulated (currently no
667 emulation will be attempted), passes -1 and sets $! to "ENOSYS". 634 emulation will be attempted), passes -1 and sets $! to "ENOSYS".
668 635
669 aio_chmod $fh_or_path, $mode, $callback->($status) 636 aio_chmod $fh_or_path, $mode, $callback->($status)
… …
713 680
714 On systems that support the AIO::WD working directory abstraction 681 On systems that support the AIO::WD working directory abstraction
715 natively, the case "[$wd, "."]" as $srcpath is specialcased - 682 natively, the case "[$wd, "."]" as $srcpath is specialcased -
716 instead of failing, "rename" is called on the absolute path of $wd. 683 instead of failing, "rename" is called on the absolute path of $wd.
717 684
685 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
686 Basically a version of "aio_rename" with an additional $flags
687 argument. Calling this with "$flags=0" is the same as calling
688 "aio_rename".
689
690 Non-zero flags are currently only supported on GNU/Linux systems
691 that support renameat2. Other systems fail with "ENOSYS" in this
692 case.
693
694 The following constants are available (missing ones are, as usual
695 0), see renameat2(2) for details:
696
697 "IO::AIO::RENAME_NOREPLACE", "IO::AIO::RENAME_EXCHANGE" and
698 "IO::AIO::RENAME_WHITEOUT".
699
718 aio_mkdir $pathname, $mode, $callback->($status) 700 aio_mkdir $pathname, $mode, $callback->($status)
719 Asynchronously mkdir (create) a directory and call the callback with 701 Asynchronously mkdir (create) a directory and call the callback with
720 the result code. $mode will be modified by the umask at the time the 702 the result code. $mode will be modified by the umask at the time the
721 request is executed, so do not change your umask. 703 request is executed, so do not change your umask.
722 704
… …
744 The flags are a combination of the following constants, ORed 726 The flags are a combination of the following constants, ORed
745 together (the flags will also be passed to the callback, possibly 727 together (the flags will also be passed to the callback, possibly
746 modified): 728 modified):
747 729
748 IO::AIO::READDIR_DENTS 730 IO::AIO::READDIR_DENTS
749 When this flag is off, then the callback gets an arrayref 731 Normally the callback gets an arrayref consisting of names only
750 consisting of names only (as with "aio_readdir"), otherwise it 732 (as with "aio_readdir"). If this flag is set, then the callback
751 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each 733 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
752 describing a single directory entry in more detail. 734 describing a single directory entry in more detail:
753 735
754 $name is the name of the entry. 736 $name is the name of the entry.
755 737
756 $type is one of the "IO::AIO::DT_xxx" constants: 738 $type is one of the "IO::AIO::DT_xxx" constants:
757 739
758 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", 740 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",
759 "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG", 741 "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",
760 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT". 742 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
761 743
762 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If 744 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If
763 you need to know, you have to run stat yourself. Also, for speed 745 you need to know, you have to run stat yourself. Also, for
764 reasons, the $type scalars are read-only: you can not modify 746 speed/memory reasons, the $type scalars are read-only: you must
765 them. 747 not modify them.
766 748
767 $inode is the inode number (which might not be exact on systems 749 $inode is the inode number (which might not be exact on systems
768 with 64 bit inode numbers and 32 bit perls). This field has 750 with 64 bit inode numbers and 32 bit perls). This field has
769 unspecified content on systems that do not deliver the inode 751 unspecified content on systems that do not deliver the inode
770 information. 752 information.
… …
782 of which names with short names are tried first. 764 of which names with short names are tried first.
783 765
784 IO::AIO::READDIR_STAT_ORDER 766 IO::AIO::READDIR_STAT_ORDER
785 When this flag is set, then the names will be returned in an 767 When this flag is set, then the names will be returned in an
786 order suitable for stat()'ing each one. That is, when you plan 768 order suitable for stat()'ing each one. That is, when you plan
787 to stat() all files in the given directory, then the returned 769 to stat() most or all files in the given directory, then the
788 order will likely be fastest. 770 returned order will likely be faster.
789 771
790 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are 772 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
791 specified, then the likely dirs come first, resulting in a less 773 specified, then the likely dirs come first, resulting in a less
792 optimal stat order. 774 optimal stat order for stat'ing all entries, but likely a more
775 optimal order for finding subdirectories.
793 776
794 IO::AIO::READDIR_FOUND_UNKNOWN 777 IO::AIO::READDIR_FOUND_UNKNOWN
795 This flag should not be set when calling "aio_readdirx". 778 This flag should not be set when calling "aio_readdirx".
796 Instead, it is being set by "aio_readdirx", when any of the 779 Instead, it is being set by "aio_readdirx", when any of the
797 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this 780 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this
798 flag therefore indicates that all $type's are known, which can 781 flag therefore indicates that all $type's are known, which can
799 be used to speed up some algorithms. 782 be used to speed up some algorithms.
800 783
784 aio_slurp $pathname, $offset, $length, $data, $callback->($status)
785 Opens, reads and closes the given file. The data is put into $data,
786 which is resized as required.
787
788 If $offset is negative, then it is counted from the end of the file.
789
790 If $length is zero, then the remaining length of the file is used.
791 Also, in this case, the same limitations to modifying $data apply as
792 when IO::AIO::mmap is used, i.e. it must only be modified in-place
793 with "substr". If the size of the file is known, specifying a
794 non-zero $length results in a performance advantage.
795
796 This request is similar to the older "aio_load" request, but since
797 it is a single request, it might be more efficient to use.
798
799 Example: load /etc/passwd into $passwd.
800
801 my $passwd;
802 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
803 $_[0] >= 0
804 or die "/etc/passwd: $!\n";
805
806 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
807 print $passwd;
808 };
809 IO::AIO::flush;
810
801 aio_load $pathname, $data, $callback->($status) 811 aio_load $pathname, $data, $callback->($status)
802 This is a composite request that tries to fully load the given file 812 This is a composite request that tries to fully load the given file
803 into memory. Status is the same as with aio_read. 813 into memory. Status is the same as with aio_read.
814
815 Using "aio_slurp" might be more efficient, as it is a single
816 request.
804 817
805 aio_copy $srcpath, $dstpath, $callback->($status) 818 aio_copy $srcpath, $dstpath, $callback->($status)
806 Try to copy the *file* (directories not supported as either source 819 Try to copy the *file* (directories not supported as either source
807 or destination) from $srcpath to $dstpath and call the callback with 820 or destination) from $srcpath to $dstpath and call the callback with
808 a status of 0 (ok) or -1 (error, see $!). 821 a status of 0 (ok) or -1 (error, see $!).
822
823 Existing destination files will be truncated.
809 824
810 This is a composite request that creates the destination file with 825 This is a composite request that creates the destination file with
811 mode 0200 and copies the contents of the source file into it using 826 mode 0200 and copies the contents of the source file into it using
812 "aio_sendfile", followed by restoring atime, mtime, access mode and 827 "aio_sendfile", followed by restoring atime, mtime, access mode and
813 uid/gid, in that order. 828 uid/gid, in that order.
… …
830 to efficiently separate the entries of directory $path into two sets 845 to efficiently separate the entries of directory $path into two sets
831 of names, directories you can recurse into (directories), and ones 846 of names, directories you can recurse into (directories), and ones
832 you cannot recurse into (everything else, including symlinks to 847 you cannot recurse into (everything else, including symlinks to
833 directories). 848 directories).
834 849
835 "aio_scandir" is a composite request that creates of many sub 850 "aio_scandir" is a composite request that generates many sub
836 requests_ $maxreq specifies the maximum number of outstanding aio 851 requests. $maxreq specifies the maximum number of outstanding aio
837 requests that this function generates. If it is "<= 0", then a 852 requests that this function generates. If it is "<= 0", then a
838 suitable default will be chosen (currently 4). 853 suitable default will be chosen (currently 4).
839 854
840 On error, the callback is called without arguments, otherwise it 855 On error, the callback is called without arguments, otherwise it
841 receives two array-refs with path-relative entry names. 856 receives two array-refs with path-relative entry names.
… …
888 Delete a directory tree starting (and including) $path, return the 903 Delete a directory tree starting (and including) $path, return the
889 status of the final "rmdir" only. This is a composite request that 904 status of the final "rmdir" only. This is a composite request that
890 uses "aio_scandir" to recurse into and rmdir directories, and unlink 905 uses "aio_scandir" to recurse into and rmdir directories, and unlink
891 everything else. 906 everything else.
892 907
908 aio_fcntl $fh, $cmd, $arg, $callback->($status)
909 aio_ioctl $fh, $request, $buf, $callback->($status)
910 These work just like the "fcntl" and "ioctl" built-in functions,
911 except they execute asynchronously and pass the return value to the
912 callback.
913
914 Both calls can be used for a lot of things, some of which make more
915 sense to run asynchronously in their own thread, while some others
916 make less sense. For example, calls that block waiting for external
917 events, such as locking, will also lock down an I/O thread while it
918 is waiting, which can deadlock the whole I/O system. At the same
919 time, there might be no alternative to using a thread to wait.
920
921 So in general, you should only use these calls for things that do
922 (filesystem) I/O, not for things that wait for other events
923 (network, other processes), although if you are careful and know
924 what you are doing, you still can.
925
926 The following constants are available and can be used for normal
927 "ioctl" and "fcntl" as well (missing ones are, as usual 0):
928
929 "F_DUPFD_CLOEXEC",
930
931 "F_OFD_GETLK", "F_OFD_SETLK", "F_OFD_GETLKW",
932
933 "FIFREEZE", "FITHAW", "FITRIM", "FICLONE", "FICLONERANGE",
934 "FIDEDUPERANGE".
935
936 "F_ADD_SEALS", "F_GET_SEALS", "F_SEAL_SEAL", "F_SEAL_SHRINK",
937 "F_SEAL_GROW" and "F_SEAL_WRITE".
938
939 "FS_IOC_GETFLAGS", "FS_IOC_SETFLAGS", "FS_IOC_GETVERSION",
940 "FS_IOC_SETVERSION", "FS_IOC_FIEMAP".
941
942 "FS_IOC_FSGETXATTR", "FS_IOC_FSSETXATTR",
943 "FS_IOC_SET_ENCRYPTION_POLICY", "FS_IOC_GET_ENCRYPTION_PWSALT",
944 "FS_IOC_GET_ENCRYPTION_POLICY", "FS_KEY_DESCRIPTOR_SIZE".
945
946 "FS_SECRM_FL", "FS_UNRM_FL", "FS_COMPR_FL", "FS_SYNC_FL",
947 "FS_IMMUTABLE_FL", "FS_APPEND_FL", "FS_NODUMP_FL", "FS_NOATIME_FL",
948 "FS_DIRTY_FL", "FS_COMPRBLK_FL", "FS_NOCOMP_FL", "FS_ENCRYPT_FL",
949 "FS_BTREE_FL", "FS_INDEX_FL", "FS_JOURNAL_DATA_FL", "FS_NOTAIL_FL",
950 "FS_DIRSYNC_FL", "FS_TOPDIR_FL", "FS_FL_USER_MODIFIABLE".
951
952 "FS_XFLAG_REALTIME", "FS_XFLAG_PREALLOC", "FS_XFLAG_IMMUTABLE",
953 "FS_XFLAG_APPEND", "FS_XFLAG_SYNC", "FS_XFLAG_NOATIME",
954 "FS_XFLAG_NODUMP", "FS_XFLAG_RTINHERIT", "FS_XFLAG_PROJINHERIT",
955 "FS_XFLAG_NOSYMLINKS", "FS_XFLAG_EXTSIZE", "FS_XFLAG_EXTSZINHERIT",
956 "FS_XFLAG_NODEFRAG", "FS_XFLAG_FILESTREAM", "FS_XFLAG_DAX",
957 "FS_XFLAG_HASATTR",
958
959 "BLKROSET", "BLKROGET", "BLKRRPART", "BLKGETSIZE", "BLKFLSBUF",
960 "BLKRASET", "BLKRAGET", "BLKFRASET", "BLKFRAGET", "BLKSECTSET",
961 "BLKSECTGET", "BLKSSZGET", "BLKBSZGET", "BLKBSZSET", "BLKGETSIZE64",
962
893 aio_sync $callback->($status) 963 aio_sync $callback->($status)
894 Asynchronously call sync and call the callback when finished. 964 Asynchronously call sync and call the callback when finished.
895 965
896 aio_fsync $fh, $callback->($status) 966 aio_fsync $fh, $callback->($status)
897 Asynchronously call fsync on the given filehandle and call the 967 Asynchronously call fsync on the given filehandle and call the
… …
933 Future versions of this function might fall back to other methods 1003 Future versions of this function might fall back to other methods
934 when "fsync" on the directory fails (such as calling "sync"). 1004 when "fsync" on the directory fails (such as calling "sync").
935 1005
936 Passes 0 when everything went ok, and -1 on error. 1006 Passes 0 when everything went ok, and -1 on error.
937 1007
938 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, 1008 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC,
939 $callback->($status) 1009 $callback->($status)
940 This is a rather advanced IO::AIO call, which only works on 1010 This is a rather advanced IO::AIO call, which only works on
941 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it 1011 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
942 also works on data scalars managed by the Sys::Mmap or Mmap modules, 1012 also works on data scalars managed by the Sys::Mmap or Mmap modules,
943 note that the scalar must only be modified in-place while an aio 1013 note that the scalar must only be modified in-place while an aio
… …
945 1015
946 It calls the "msync" function of your OS, if available, with the 1016 It calls the "msync" function of your OS, if available, with the
947 memory area starting at $offset in the string and ending $length 1017 memory area starting at $offset in the string and ending $length
948 bytes later. If $length is negative, counts from the end, and if 1018 bytes later. If $length is negative, counts from the end, and if
949 $length is "undef", then it goes till the end of the string. The 1019 $length is "undef", then it goes till the end of the string. The
950 flags can be a combination of "IO::AIO::MS_ASYNC", 1020 flags can be either "IO::AIO::MS_ASYNC" or "IO::AIO::MS_SYNC", plus
951 "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC". 1021 an optional "IO::AIO::MS_INVALIDATE".
952 1022
953 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, 1023 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
954 $callback->($status) 1024 $callback->($status)
955 This is a rather advanced IO::AIO call, which works best on 1025 This is a rather advanced IO::AIO call, which works best on
956 mmap(2)ed scalars. 1026 mmap(2)ed scalars.
… …
987 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1057 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
988 aio_mlock $data; # mlock in background 1058 aio_mlock $data; # mlock in background
989 1059
990 aio_mlockall $flags, $callback->($status) 1060 aio_mlockall $flags, $callback->($status)
991 Calls the "mlockall" function with the given $flags (a combination 1061 Calls the "mlockall" function with the given $flags (a combination
992 of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE"). 1062 of "IO::AIO::MCL_CURRENT", "IO::AIO::MCL_FUTURE" and
1063 "IO::AIO::MCL_ONFAULT").
993 1064
994 On systems that do not implement "mlockall", this function returns 1065 On systems that do not implement "mlockall", this function returns
995 -1 and sets errno to "ENOSYS". 1066 -1 and sets errno to "ENOSYS". Similarly, flag combinations not
1067 supported by the system result in a return value of -1 with errno
1068 being set to "EINVAL".
996 1069
997 Note that the corresponding "munlockall" is synchronous and is 1070 Note that the corresponding "munlockall" is synchronous and is
998 documented under "MISCELLANEOUS FUNCTIONS". 1071 documented under "MISCELLANEOUS FUNCTIONS".
999 1072
1000 Example: asynchronously lock all current and future pages into 1073 Example: asynchronously lock all current and future pages into
… …
1042 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", 1115 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
1043 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", 1116 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
1044 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" 1117 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
1045 or "IO::AIO::FIEMAP_EXTENT_SHARED". 1118 or "IO::AIO::FIEMAP_EXTENT_SHARED".
1046 1119
1047 At the time of this writing (Linux 3.2), this requets is unreliable 1120 At the time of this writing (Linux 3.2), this request is unreliable
1048 unless $count is "undef", as the kernel has all sorts of bugs 1121 unless $count is "undef", as the kernel has all sorts of bugs
1049 preventing it to return all extents of a range for files with large 1122 preventing it to return all extents of a range for files with a
1050 number of extents. The code works around all these issues if $count 1123 large number of extents. The code (only) works around all these
1051 is undef. 1124 issues if $count is "undef".
1052 1125
1053 aio_group $callback->(...) 1126 aio_group $callback->(...)
1054 This is a very special aio request: Instead of doing something, it 1127 This is a very special aio request: Instead of doing something, it
1055 is a container for other aio requests, which is useful if you want 1128 is a container for other aio requests, which is useful if you want
1056 to bundle many requests into a single, composite, request with a 1129 to bundle many requests into a single, composite, request with a
… …
1165 There are some caveats: when directories get renamed (or deleted), the 1238 There are some caveats: when directories get renamed (or deleted), the
1166 pathname string doesn't change, so will point to the new directory (or 1239 pathname string doesn't change, so will point to the new directory (or
1167 nowhere at all), while the directory fd, if available on the system, 1240 nowhere at all), while the directory fd, if available on the system,
1168 will still point to the original directory. Most functions accepting a 1241 will still point to the original directory. Most functions accepting a
1169 pathname will use the directory fd on newer systems, and the string on 1242 pathname will use the directory fd on newer systems, and the string on
1170 older systems. Some functions (such as realpath) will always rely on the 1243 older systems. Some functions (such as "aio_realpath") will always rely
1171 string form of the pathname. 1244 on the string form of the pathname.
1172 1245
1173 So this functionality is mainly useful to get some protection against 1246 So this functionality is mainly useful to get some protection against
1174 "chdir", to easily get an absolute path out of a relative path for 1247 "chdir", to easily get an absolute path out of a relative path for
1175 future reference, and to speed up doing many operations in the same 1248 future reference, and to speed up doing many operations in the same
1176 directory (e.g. when stat'ing all files in a directory). 1249 directory (e.g. when stat'ing all files in a directory).
… …
1189 fails the request with "ENOENT", there is often no need for error 1262 fails the request with "ENOENT", there is often no need for error
1190 checking in the "aio_wd" callback, as future requests using the 1263 checking in the "aio_wd" callback, as future requests using the
1191 value will fail in the expected way. 1264 value will fail in the expected way.
1192 1265
1193 IO::AIO::CWD 1266 IO::AIO::CWD
1194 This is a compiletime constant (object) that represents the process 1267 This is a compile time constant (object) that represents the process
1195 current working directory. 1268 current working directory.
1196 1269
1197 Specifying this object as working directory object for a pathname is 1270 Specifying this object as working directory object for a pathname is
1198 as if the pathname would be specified directly, without a directory 1271 as if the pathname would be specified directly, without a directory
1199 object. For example, these calls are functionally identical: 1272 object. For example, these calls are functionally identical:
… …
1424 Strictly equivalent to: 1497 Strictly equivalent to:
1425 1498
1426 IO::AIO::poll_wait, IO::AIO::poll_cb 1499 IO::AIO::poll_wait, IO::AIO::poll_cb
1427 while IO::AIO::nreqs; 1500 while IO::AIO::nreqs;
1428 1501
1502 This function can be useful at program aborts, to make sure
1503 outstanding I/O has been done ("IO::AIO" uses an "END" block which
1504 already calls this function on normal exits), or when you are merely
1505 using "IO::AIO" for its more advanced functions, rather than for
1506 async I/O, e.g.:
1507
1508 my ($dirs, $nondirs);
1509 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1510 IO::AIO::flush;
1511 # $dirs, $nondirs are now set
1512
1429 IO::AIO::max_poll_reqs $nreqs 1513 IO::AIO::max_poll_reqs $nreqs
1430 IO::AIO::max_poll_time $seconds 1514 IO::AIO::max_poll_time $seconds
1431 These set the maximum number of requests (default 0, meaning 1515 These set the maximum number of requests (default 0, meaning
1432 infinity) that are being processed by "IO::AIO::poll_cb" in one 1516 infinity) that are being processed by "IO::AIO::poll_cb" in one
1433 call, respectively the maximum amount of time (default 0, meaning 1517 call, respectively the maximum amount of time (default 0, meaning
… …
1522 no longer exceeded. 1606 no longer exceeded.
1523 1607
1524 In other words, this setting does not enforce a queue limit, but can 1608 In other words, this setting does not enforce a queue limit, but can
1525 be used to make poll functions block if the limit is exceeded. 1609 be used to make poll functions block if the limit is exceeded.
1526 1610
1527 This is a very bad function to use in interactive programs because 1611 This is a bad function to use in interactive programs because it
1528 it blocks, and a bad way to reduce concurrency because it is 1612 blocks, and a bad way to reduce concurrency because it is inexact.
1529 inexact: Better use an "aio_group" together with a feed callback. 1613 If you need to issue many requests without being able to call a poll
1614 function on demand, it is better to use an "aio_group" together with
1615 a feed callback.
1530 1616
1531 Its main use is in scripts without an event loop - when you want to 1617 Its main use is in scripts without an event loop - when you want to
1532 stat a lot of files, you can write somehting like this: 1618 stat a lot of files, you can write something like this:
1533 1619
1534 IO::AIO::max_outstanding 32; 1620 IO::AIO::max_outstanding 32;
1535 1621
1536 for my $path (...) { 1622 for my $path (...) {
1537 aio_stat $path , ...; 1623 aio_stat $path , ...;
… …
1539 } 1625 }
1540 1626
1541 IO::AIO::flush; 1627 IO::AIO::flush;
1542 1628
1543 The call to "poll_cb" inside the loop will normally return 1629 The call to "poll_cb" inside the loop will normally return
1544 instantly, but as soon as more thna 32 reqeusts are in-flight, it 1630 instantly, allowing the loop to progress, but as soon as more than
1545 will block until some requests have been handled. This keeps the 1631 32 requests are in-flight, it will block until some requests have
1546 loop from pushing a large number of "aio_stat" requests onto the 1632 been handled. This keeps the loop from pushing a large number of
1547 queue. 1633 "aio_stat" requests onto the queue (which, with many paths to stat,
1634 can use up a lot of memory).
1548 1635
1549 The default value for "max_outstanding" is very large, so there is 1636 The default value for "max_outstanding" is very large, so there is
1550 no practical limit on the number of outstanding requests. 1637 no practical limit on the number of outstanding requests.
1551 1638
1552 STATISTICAL INFORMATION 1639 STATISTICAL INFORMATION
… …
1566 1653
1567 IO::AIO::npending 1654 IO::AIO::npending
1568 Returns the number of requests currently in the pending state 1655 Returns the number of requests currently in the pending state
1569 (executed, but not yet processed by poll_cb). 1656 (executed, but not yet processed by poll_cb).
1570 1657
1658 SUBSECOND STAT TIME ACCESS
1659 Both "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" functions can
1660 generally find access/modification and change times with subsecond time
1661 accuracy of the system supports it, but perl's built-in functions only
1662 return the integer part.
1663
1664 The following functions return the timestamps of the most recent stat
1665 with subsecond precision on most systems and work both after
1666 "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" calls. Their return
1667 value is only meaningful after a successful "stat"/"lstat" call, or
1668 during/after a successful "aio_stat"/"aio_lstat" callback.
1669
1670 This is similar to the Time::HiRes "stat" functions, but can return full
1671 resolution without rounding and work with standard perl "stat",
1672 alleviating the need to call the special "Time::HiRes" functions, which
1673 do not act like their perl counterparts.
1674
1675 On operating systems or file systems where subsecond time resolution is
1676 not supported or could not be detected, a fractional part of 0 is
1677 returned, so it is always safe to call these functions.
1678
1679 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime,
1680 IO::AIO::st_btime
1681 Return the access, modication, change or birth time, respectively,
1682 including fractional part. Due to the limited precision of floating
1683 point, the accuracy on most platforms is only a bit better than
1684 milliseconds for times around now - see the *nsec* function family,
1685 below, for full accuracy.
1686
1687 File birth time is only available when the OS and perl support it
1688 (on FreeBSD and NetBSD at the time of this writing, although support
1689 is adaptive, so if your OS/perl gains support, IO::AIO can take
1690 advantage of it). On systems where it isn't available, 0 is
1691 currently returned, but this might change to "undef" in a future
1692 version.
1693
1694 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
1695 Returns access, modification, change and birth time all in one go,
1696 and maybe more times in the future version.
1697
1698 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec,
1699 IO::AIO::st_ctimensec, IO::AIO::st_btimensec
1700 Return the fractional access, modifcation, change or birth time, in
1701 nanoseconds, as an integer in the range 0 to 999999999.
1702
1703 Note that no accessors are provided for access, modification and
1704 change times - you need to get those from "stat _" if required ("int
1705 IO::AIO::st_atime" and so on will *not* generally give you the
1706 correct value).
1707
1708 $seconds = IO::AIO::st_btimesec
1709 The (integral) seconds part of the file birth time, if available.
1710
1711 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
1712 Like the functions above, but returns all four times in one go (and
1713 maybe more in future versions).
1714
1715 $counter = IO::AIO::st_gen
1716 Returns the generation counter (in practice this is just a random
1717 number) of the file. This is only available on platforms which have
1718 this member in their "struct stat" (most BSDs at the time of this
1719 writing) and generally only to the root usert. If unsupported, 0 is
1720 returned, but this might change to "undef" in a future version.
1721
1722 Example: print the high resolution modification time of /etc, using
1723 "stat", and "IO::AIO::aio_stat".
1724
1725 if (stat "/etc") {
1726 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
1727 }
1728
1729 IO::AIO::aio_stat "/etc", sub {
1730 $_[0]
1731 and return;
1732
1733 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
1734 };
1735
1736 IO::AIO::flush;
1737
1738 Output of the awbove on my system, showing reduced and full accuracy:
1739
1740 stat(/etc) mtime: 1534043702.020808
1741 aio_stat(/etc) mtime: 1534043702.020807792
1742
1571 MISCELLANEOUS FUNCTIONS 1743 MISCELLANEOUS FUNCTIONS
1572 IO::AIO implements some functions that are useful when you want to use 1744 IO::AIO implements some functions that are useful when you want to use
1573 some "Advanced I/O" function not available to in Perl, without going the 1745 some "Advanced I/O" function not available to in Perl, without going the
1574 "Asynchronous I/O" route. Many of these have an asynchronous "aio_*" 1746 "Asynchronous I/O" route. Many of these have an asynchronous "aio_*"
1575 counterpart. 1747 counterpart.
1748
1749 $retval = IO::AIO::fexecve $fh, $argv, $envp
1750 A more-or-less direct equivalent to the POSIX "fexecve" functions,
1751 which allows you to specify the program to be executed via a file
1752 descriptor (or handle). Returns -1 and sets errno to "ENOSYS" if not
1753 available.
1754
1755 $retval = IO::AIO::mount $special, $path, $fstype, $flags = 0, $data =
1756 undef
1757 Calls the GNU/Linux mount syscall with the given arguments. All
1758 except $flags are strings, and if $data is "undef", a "NULL" will be
1759 passed.
1760
1761 The following values for $flags are available:
1762
1763 "IO::AIO::MS_RDONLY", "IO::AIO::MS_NOSUID", "IO::AIO::MS_NODEV",
1764 "IO::AIO::MS_NOEXEC", "IO::AIO::MS_SYNCHRONOUS",
1765 "IO::AIO::MS_REMOUNT", "IO::AIO::MS_MANDLOCK",
1766 "IO::AIO::MS_DIRSYNC", "IO::AIO::MS_NOATIME",
1767 "IO::AIO::MS_NODIRATIME", "IO::AIO::MS_BIND", "IO::AIO::MS_MOVE",
1768 "IO::AIO::MS_REC", "IO::AIO::MS_SILENT", "IO::AIO::MS_POSIXACL",
1769 "IO::AIO::MS_UNBINDABLE", "IO::AIO::MS_PRIVATE",
1770 "IO::AIO::MS_SLAVE", "IO::AIO::MS_SHARED", "IO::AIO::MS_RELATIME",
1771 "IO::AIO::MS_KERNMOUNT", "IO::AIO::MS_I_VERSION",
1772 "IO::AIO::MS_STRICTATIME", "IO::AIO::MS_LAZYTIME",
1773 "IO::AIO::MS_ACTIVE", "IO::AIO::MS_NOUSER", "IO::AIO::MS_RMT_MASK",
1774 "IO::AIO::MS_MGC_VAL" and "IO::AIO::MS_MGC_MSK".
1775
1776 $retval = IO::AIO::umount $path, $flags = 0
1777 Invokes the GNU/Linux "umount" or "umount2" syscalls. Always calls
1778 "umount" if $flags is 0, otherwqise always tries to call "umount2".
1779
1780 The following $flags are available:
1781
1782 "IO::AIO::MNT_FORCE", "IO::AIO::MNT_DETACH", "IO::AIO::MNT_EXPIRE"
1783 and "IO::AIO::UMOUNT_NOFOLLOW".
1784
1785 $numfd = IO::AIO::get_fdlimit
1786 Tries to find the current file descriptor limit and returns it, or
1787 "undef" and sets $! in case of an error. The limit is one larger
1788 than the highest valid file descriptor number.
1789
1790 IO::AIO::min_fdlimit [$numfd]
1791 Try to increase the current file descriptor limit(s) to at least
1792 $numfd by changing the soft or hard file descriptor resource limit.
1793 If $numfd is missing, it will try to set a very high limit, although
1794 this is not recommended when you know the actual minimum that you
1795 require.
1796
1797 If the limit cannot be raised enough, the function makes a
1798 best-effort attempt to increase the limit as much as possible, using
1799 various tricks, while still failing. You can query the resulting
1800 limit using "IO::AIO::get_fdlimit".
1801
1802 If an error occurs, returns "undef" and sets $!, otherwise returns
1803 true.
1576 1804
1577 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1805 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1578 Calls the "eio_sendfile_sync" function, which is like 1806 Calls the "eio_sendfile_sync" function, which is like
1579 "aio_sendfile", but is blocking (this makes most sense if you know 1807 "aio_sendfile", but is blocking (this makes most sense if you know
1580 the input data is likely cached already and the output filehandle is 1808 the input data is likely cached already and the output filehandle is
… …
1597 details). The following advice constants are available: 1825 details). The following advice constants are available:
1598 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", 1826 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1599 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", 1827 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1600 "IO::AIO::MADV_DONTNEED". 1828 "IO::AIO::MADV_DONTNEED".
1601 1829
1830 If $offset is negative, counts from the end. If $length is negative,
1831 the remaining length of the $scalar is used. If possible, $length
1832 will be reduced to fit into the $scalar.
1833
1602 On systems that do not implement "posix_madvise", this function 1834 On systems that do not implement "posix_madvise", this function
1603 returns ENOSYS, otherwise the return value of "posix_madvise". 1835 returns ENOSYS, otherwise the return value of "posix_madvise".
1604 1836
1605 IO::AIO::mprotect $scalar, $offset, $len, $protect 1837 IO::AIO::mprotect $scalar, $offset, $len, $protect
1606 Simply calls the "mprotect" function on the preferably AIO::mmap'ed 1838 Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1607 $scalar (see its manpage for details). The following protect 1839 $scalar (see its manpage for details). The following protect
1608 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", 1840 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1609 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". 1841 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1610 1842
1843 If $offset is negative, counts from the end. If $length is negative,
1844 the remaining length of the $scalar is used. If possible, $length
1845 will be reduced to fit into the $scalar.
1846
1611 On systems that do not implement "mprotect", this function returns 1847 On systems that do not implement "mprotect", this function returns
1612 ENOSYS, otherwise the return value of "mprotect". 1848 ENOSYS, otherwise the return value of "mprotect".
1613 1849
1614 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1850 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1615 Memory-maps a file (or anonymous memory range) and attaches it to 1851 Memory-maps a file (or anonymous memory range) and attaches it to
1616 the given $scalar, which will act like a string scalar. Returns true 1852 the given $scalar, which will act like a string scalar. Returns true
1617 on success, and false otherwise. 1853 on success, and false otherwise.
1618 1854
1855 The scalar must exist, but its contents do not matter - this means
1856 you cannot use a nonexistant array or hash element. When in doubt,
1857 "undef" the scalar first.
1858
1619 The only operations allowed on the scalar are "substr"/"vec" that 1859 The only operations allowed on the mmapped scalar are
1620 don't change the string length, and most read-only operations such 1860 "substr"/"vec", which don't change the string length, and most
1621 as copying it or searching it with regexes and so on. 1861 read-only operations such as copying it or searching it with regexes
1862 and so on.
1622 1863
1623 Anything else is unsafe and will, at best, result in memory leaks. 1864 Anything else is unsafe and will, at best, result in memory leaks.
1624 1865
1625 The memory map associated with the $scalar is automatically removed 1866 The memory map associated with the $scalar is automatically removed
1626 when the $scalar is destroyed, or when the "IO::AIO::mmap" or 1867 when the $scalar is undef'd or destroyed, or when the
1627 "IO::AIO::munmap" functions are called. 1868 "IO::AIO::mmap" or "IO::AIO::munmap" functions are called on it.
1628 1869
1629 This calls the "mmap"(2) function internally. See your system's 1870 This calls the "mmap"(2) function internally. See your system's
1630 manual page for details on the $length, $prot and $flags parameters. 1871 manual page for details on the $length, $prot and $flags parameters.
1631 1872
1632 The $length must be larger than zero and smaller than the actual 1873 The $length must be larger than zero and smaller than the actual
… …
1638 1879
1639 $flags can be a combination of "IO::AIO::MAP_SHARED" or 1880 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1640 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when 1881 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1641 not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to 1882 not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to
1642 "MAP_ANON" if your system only provides this constant), 1883 "MAP_ANON" if your system only provides this constant),
1884 "IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE",
1643 "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", 1885 "IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK",
1644 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE", 1886 "IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN",
1645 "IO::AIO::MAP_NONBLOCK", "IO::AIO::MAP_FIXED",
1646 "IO::AIO::MAP_GROWSDOWN", "IO::AIO::MAP_32BIT",
1647 "IO::AIO::MAP_HUGETLB" or "IO::AIO::MAP_STACK". 1887 "IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_STACK",
1888 "IO::AIO::MAP_FIXED_NOREPLACE", "IO::AIO::MAP_SHARED_VALIDATE",
1889 "IO::AIO::MAP_SYNC" or "IO::AIO::MAP_UNINITIALIZED".
1648 1890
1649 If $fh is "undef", then a file descriptor of -1 is passed. 1891 If $fh is "undef", then a file descriptor of -1 is passed.
1650 1892
1651 $offset is the offset from the start of the file - it generally must 1893 $offset is the offset from the start of the file - it generally must
1652 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. 1894 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
… …
1664 1906
1665 my $fast_md5 = md5 $data; 1907 my $fast_md5 = md5 $data;
1666 1908
1667 IO::AIO::munmap $scalar 1909 IO::AIO::munmap $scalar
1668 Removes a previous mmap and undefines the $scalar. 1910 Removes a previous mmap and undefines the $scalar.
1911
1912 IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[,
1913 $new_address = 0]
1914 Calls the Linux-specific mremap(2) system call. The $scalar must
1915 have been mapped by "IO::AIO::mmap", and $flags must currently
1916 either be 0 or "IO::AIO::MREMAP_MAYMOVE".
1917
1918 Returns true if successful, and false otherwise. If the underlying
1919 mmapped region has changed address, then the true value has the
1920 numerical value 1, otherwise it has the numerical value 0:
1921
1922 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
1923 or die "mremap: $!";
1924
1925 if ($success*1) {
1926 warn "scalar has chanegd address in memory\n";
1927 }
1928
1929 "IO::AIO::MREMAP_FIXED" and the $new_address argument are currently
1930 implemented, but not supported and might go away in a future
1931 version.
1932
1933 On systems where this call is not supported or is not emulated, this
1934 call returns falls and sets $! to "ENOSYS".
1935
1936 IO::AIO::mlockall $flags
1937 Calls the "eio_mlockall_sync" function, which is like
1938 "aio_mlockall", but is blocking.
1669 1939
1670 IO::AIO::munlock $scalar, $offset = 0, $length = undef 1940 IO::AIO::munlock $scalar, $offset = 0, $length = undef
1671 Calls the "munlock" function, undoing the effects of a previous 1941 Calls the "munlock" function, undoing the effects of a previous
1672 "aio_mlock" call (see its description for details). 1942 "aio_mlock" call (see its description for details).
1673 1943
1674 IO::AIO::munlockall 1944 IO::AIO::munlockall
1675 Calls the "munlockall" function. 1945 Calls the "munlockall" function.
1676 1946
1677 On systems that do not implement "munlockall", this function returns 1947 On systems that do not implement "munlockall", this function returns
1678 ENOSYS, otherwise the return value of "munlockall". 1948 ENOSYS, otherwise the return value of "munlockall".
1949
1950 $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
1951 Uses the GNU/Linux accept4(2) syscall, if available, to accept a
1952 socket and return the new file handle on success, or sets $! and
1953 returns "undef" on error.
1954
1955 The remote name of the new socket will be stored in $sockaddr, which
1956 will be extended to allow for at least $sockaddr_maxlen octets. If
1957 the socket name does not fit into $sockaddr_maxlen octets, this is
1958 signaled by returning a longer string in $sockaddr, which might or
1959 might not be truncated.
1960
1961 To accept name-less sockets, use "undef" for $sockaddr and 0 for
1962 $sockaddr_maxlen.
1963
1964 The main reasons to use this syscall rather than portable accept(2)
1965 are that you can specify "SOCK_NONBLOCK" and/or "SOCK_CLOEXEC" flags
1966 and you can accept name-less sockets by specifying 0 for
1967 $sockaddr_maxlen, which is sadly not possible with perl's interface
1968 to "accept".
1679 1969
1680 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags 1970 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1681 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or 1971 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1682 $w_off are "undef", then "NULL" is passed for these, otherwise they 1972 $w_off are "undef", then "NULL" is passed for these, otherwise they
1683 should be the file offset. 1973 should be the file offset.
… …
1718 2008
1719 Please refer to pipe2(2) for more info on the $flags, but at the 2009 Please refer to pipe2(2) for more info on the $flags, but at the
1720 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK" 2010 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"
1721 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were 2011 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
1722 supported. 2012 supported.
2013
2014 Example: create a pipe race-free w.r.t. threads and fork:
2015
2016 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2017 or die "pipe2: $!\n";
2018
2019 $fh = IO::AIO::memfd_create $pathname[, $flags]
2020 This is a direct interface to the Linux memfd_create(2) system call.
2021 The (unhelpful) default for $flags is 0, but your default should be
2022 "IO::AIO::MFD_CLOEXEC".
2023
2024 On success, the new memfd filehandle is returned, otherwise returns
2025 "undef". If the memfd_create syscall is missing, fails with
2026 "ENOSYS".
2027
2028 Please refer to memfd_create(2) for more info on this call.
2029
2030 The following $flags values are available: "IO::AIO::MFD_CLOEXEC",
2031 "IO::AIO::MFD_ALLOW_SEALING", "IO::AIO::MFD_HUGETLB",
2032 "IO::AIO::MFD_HUGETLB_2MB" and "IO::AIO::MFD_HUGETLB_1GB".
2033
2034 Example: create a new memfd.
2035
2036 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2037 or die "memfd_create: $!\n";
2038
2039 $fh = IO::AIO::pidfd_open $pid[, $flags]
2040 This is an interface to the Linux pidfd_open(2) system call. The
2041 default for $flags is 0.
2042
2043 On success, a new pidfd filehandle is returned (that is already set
2044 to close-on-exec), otherwise returns "undef". If the syscall is
2045 missing, fails with "ENOSYS".
2046
2047 Example: open pid 6341 as pidfd.
2048
2049 my $fh = IO::AIO::pidfd_open 6341
2050 or die "pidfd_open: $!\n";
2051
2052 $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[,
2053 $flags]]
2054 This is an interface to the Linux pidfd_send_signal system call. The
2055 default for $siginfo is "undef" and the default for $flags is 0.
2056
2057 Returns the system call status. If the syscall is missing, fails
2058 with "ENOSYS".
2059
2060 When specified, $siginfo must be a reference to a hash with one or
2061 more of the following members:
2062
2063 code - the "si_code" member
2064 pid - the "si_pid" member
2065 uid - the "si_uid" member
2066 value_int - the "si_value.sival_int" member
2067 value_ptr - the "si_value.sival_ptr" member, specified as an integer
2068
2069 Example: send a SIGKILL to the specified process.
2070
2071 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
2072 and die "pidfd_send_signal: $!\n";
2073
2074 Example: send a SIGKILL to the specified process with extra data.
2075
2076 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
2077 and die "pidfd_send_signal: $!\n";
2078
2079 $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
2080 This is an interface to the Linux pidfd_getfd system call. The
2081 default for $flags is 0.
2082
2083 On success, returns a dup'ed copy of the target file descriptor
2084 (specified as an integer) returned (that is already set to
2085 close-on-exec), otherwise returns "undef". If the syscall is
2086 missing, fails with "ENOSYS".
2087
2088 Example: get a copy of standard error of another process and print
2089 soemthing to it.
2090
2091 my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
2092 or die "pidfd_getfd: $!\n";
2093 print $errfh "stderr\n";
2094
2095 $fh = IO::AIO::eventfd [$initval, [$flags]]
2096 This is a direct interface to the Linux eventfd(2) system call. The
2097 (unhelpful) defaults for $initval and $flags are 0 for both.
2098
2099 On success, the new eventfd filehandle is returned, otherwise
2100 returns "undef". If the eventfd syscall is missing, fails with
2101 "ENOSYS".
2102
2103 Please refer to eventfd(2) for more info on this call.
2104
2105 The following symbol flag values are available:
2106 "IO::AIO::EFD_CLOEXEC", "IO::AIO::EFD_NONBLOCK" and
2107 "IO::AIO::EFD_SEMAPHORE" (Linux 2.6.30).
2108
2109 Example: create a new eventfd filehandle:
2110
2111 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2112 or die "eventfd: $!\n";
2113
2114 $fh = IO::AIO::timerfd_create $clockid[, $flags]
2115 This is a direct interface to the Linux timerfd_create(2) system
2116 call. The (unhelpful) default for $flags is 0, but your default
2117 should be "IO::AIO::TFD_CLOEXEC".
2118
2119 On success, the new timerfd filehandle is returned, otherwise
2120 returns "undef". If the timerfd_create syscall is missing, fails
2121 with "ENOSYS".
2122
2123 Please refer to timerfd_create(2) for more info on this call.
2124
2125 The following $clockid values are available:
2126 "IO::AIO::CLOCK_REALTIME", "IO::AIO::CLOCK_MONOTONIC"
2127 "IO::AIO::CLOCK_CLOCK_BOOTTIME" (Linux 3.15)
2128 "IO::AIO::CLOCK_CLOCK_REALTIME_ALARM" (Linux 3.11) and
2129 "IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM" (Linux 3.11).
2130
2131 The following $flags values are available (Linux 2.6.27):
2132 "IO::AIO::TFD_NONBLOCK" and "IO::AIO::TFD_CLOEXEC".
2133
2134 Example: create a new timerfd and set it to one-second repeated
2135 alarms, then wait for two alarms:
2136
2137 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2138 or die "timerfd_create: $!\n";
2139
2140 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2141 or die "timerfd_settime: $!\n";
2142
2143 for (1..2) {
2144 8 == sysread $fh, my $buf, 8
2145 or die "timerfd read failure\n";
2146
2147 printf "number of expirations (likely 1): %d\n",
2148 unpack "Q", $buf;
2149 }
2150
2151 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags,
2152 $new_interval, $nbw_value
2153 This is a direct interface to the Linux timerfd_settime(2) system
2154 call. Please refer to its manpage for more info on this call.
2155
2156 The new itimerspec is specified using two (possibly fractional)
2157 second values, $new_interval and $new_value).
2158
2159 On success, the current interval and value are returned (as per
2160 "timerfd_gettime"). On failure, the empty list is returned.
2161
2162 The following $flags values are available:
2163 "IO::AIO::TFD_TIMER_ABSTIME" and "IO::AIO::TFD_TIMER_CANCEL_ON_SET".
2164
2165 See "IO::AIO::timerfd_create" for a full example.
2166
2167 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2168 This is a direct interface to the Linux timerfd_gettime(2) system
2169 call. Please refer to its manpage for more info on this call.
2170
2171 On success, returns the current values of interval and value for the
2172 given timerfd (as potentially fractional second values). On failure,
2173 the empty list is returned.
1723 2174
1724EVENT LOOP INTEGRATION 2175EVENT LOOP INTEGRATION
1725 It is recommended to use AnyEvent::AIO to integrate IO::AIO 2176 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1726 automatically into many event loops: 2177 automatically into many event loops:
1727 2178
… …
1777 forking, if "IO::AIO" was used in the parent. Calling it while 2228 forking, if "IO::AIO" was used in the parent. Calling it while
1778 IO::AIO is active in the process will result in undefined behaviour. 2229 IO::AIO is active in the process will result in undefined behaviour.
1779 Calling it at any time will also result in any undefined (by POSIX) 2230 Calling it at any time will also result in any undefined (by POSIX)
1780 behaviour. 2231 behaviour.
1781 2232
2233 LINUX-SPECIFIC CALLS
2234 When a call is documented as "linux-specific" then this means it
2235 originated on GNU/Linux. "IO::AIO" will usually try to autodetect the
2236 availability and compatibility of such calls regardless of the platform
2237 it is compiled on, so platforms such as FreeBSD which often implement
2238 these calls will work. When in doubt, call them and see if they fail wth
2239 "ENOSYS".
2240
1782 MEMORY USAGE 2241 MEMORY USAGE
1783 Per-request usage: 2242 Per-request usage:
1784 2243
1785 Each aio request uses - depending on your architecture - around 100-200 2244 Each aio request uses - depending on your architecture - around 100-200
1786 bytes of memory. In addition, stat requests need a stat buffer (possibly 2245 bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
1796 In the execution phase, some aio requests require more memory for 2255 In the execution phase, some aio requests require more memory for
1797 temporary buffers, and each thread requires a stack and other data 2256 temporary buffers, and each thread requires a stack and other data
1798 structures (usually around 16k-128k, depending on the OS). 2257 structures (usually around 16k-128k, depending on the OS).
1799 2258
1800KNOWN BUGS 2259KNOWN BUGS
1801 Known bugs will be fixed in the next release. 2260 Known bugs will be fixed in the next release :)
2261
2262KNOWN ISSUES
2263 Calls that try to "import" foreign memory areas (such as "IO::AIO::mmap"
2264 or "IO::AIO::aio_slurp") do not work with generic lvalues, such as
2265 non-created hash slots or other scalars I didn't think of. It's best to
2266 avoid such and either use scalar variables or making sure that the
2267 scalar exists (e.g. by storing "undef") and isn't "funny" (e.g. tied).
2268
2269 I am not sure anything can be done about this, so this is considered a
2270 known issue, rather than a bug.
1802 2271
1803SEE ALSO 2272SEE ALSO
1804 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a 2273 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
1805 more natural syntax. 2274 more natural syntax and IO::FDPass for file descriptor passing.
1806 2275
1807AUTHOR 2276AUTHOR
1808 Marc Lehmann <schmorp@schmorp.de> 2277 Marc Lehmann <schmorp@schmorp.de>
1809 http://home.schmorp.de/ 2278 http://home.schmorp.de/
1810 2279

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