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Revision 1.58 by root, Sun May 1 17:19:39 2016 UTC vs.
Revision 1.68 by root, Mon Sep 5 00:04:07 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.
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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
… …
192 aio_syncfs $fh, $callback->($status) 197 aio_syncfs $fh, $callback->($status)
193 aio_fsync $fh, $callback->($status) 198 aio_fsync $fh, $callback->($status)
194 aio_fdatasync $fh, $callback->($status) 199 aio_fdatasync $fh, $callback->($status)
195 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 200 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
196 aio_pathsync $pathname, $callback->($status) 201 aio_pathsync $pathname, $callback->($status)
197 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 202 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
198 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 203 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
199 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 204 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
200 aio_mlockall $flags, $callback->($status) 205 aio_mlockall $flags, $callback->($status)
201 aio_group $callback->(...) 206 aio_group $callback->(...)
202 aio_nop $callback->() 207 aio_nop $callback->()
… …
216 IO::AIO::idle_timeout $seconds 221 IO::AIO::idle_timeout $seconds
217 IO::AIO::max_outstanding $maxreqs 222 IO::AIO::max_outstanding $maxreqs
218 IO::AIO::nreqs 223 IO::AIO::nreqs
219 IO::AIO::nready 224 IO::AIO::nready
220 IO::AIO::npending 225 IO::AIO::npending
226 IO::AIO::reinit
227
228 $nfd = IO::AIO::get_fdlimit
229 IO::AIO::min_fdlimit $nfd
221 230
222 IO::AIO::sendfile $ofh, $ifh, $offset, $count 231 IO::AIO::sendfile $ofh, $ifh, $offset, $count
223 IO::AIO::fadvise $fh, $offset, $len, $advice 232 IO::AIO::fadvise $fh, $offset, $len, $advice
233 IO::AIO::fexecve $fh, $argv, $envp
234
224 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 235 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
225 IO::AIO::munmap $scalar 236 IO::AIO::munmap $scalar
237 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
226 IO::AIO::madvise $scalar, $offset, $length, $advice 238 IO::AIO::madvise $scalar, $offset, $length, $advice
227 IO::AIO::mprotect $scalar, $offset, $length, $protect 239 IO::AIO::mprotect $scalar, $offset, $length, $protect
228 IO::AIO::munlock $scalar, $offset = 0, $length = undef 240 IO::AIO::munlock $scalar, $offset = 0, $length = undef
229 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]
230 269
231 API NOTES 270 API NOTES
232 All the "aio_*" calls are more or less thin wrappers around the syscall 271 All the "aio_*" calls are more or less thin wrappers around the syscall
233 with the same name (sans "aio_"). The arguments are similar or 272 with the same name (sans "aio_"). The arguments are similar or
234 identical, and they all accept an additional (and optional) $callback 273 identical, and they all accept an additional (and optional) $callback
… …
332 "O_APPEND"), the following POSIX and non-POSIX constants are 371 "O_APPEND"), the following POSIX and non-POSIX constants are
333 available (missing ones on your system are, as usual, 0): 372 available (missing ones on your system are, as usual, 0):
334 373
335 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 374 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
336 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 375 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
337 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", and 376 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", "O_TTY_INIT"
338 "O_TTY_INIT". 377 and "O_ACCMODE".
339 378
340 aio_close $fh, $callback->($status) 379 aio_close $fh, $callback->($status)
341 Asynchronously close a file and call the callback with the result 380 Asynchronously close a file and call the callback with the result
342 code. 381 code.
343 382
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373 412
374 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 413 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
375 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 414 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
376 Reads or writes $length bytes from or to the specified $fh and 415 Reads or writes $length bytes from or to the specified $fh and
377 $offset into the scalar given by $data and offset $dataoffset and 416 $offset into the scalar given by $data and offset $dataoffset and
378 calls the callback without the actual number of bytes read (or -1 on 417 calls the callback with the actual number of bytes transferred (or
379 error, just like the syscall). 418 -1 on error, just like the syscall).
380 419
381 "aio_read" will, like "sysread", shrink or grow the $data scalar to 420 "aio_read" will, like "sysread", shrink or grow the $data scalar to
382 offset plus the actual number of bytes read. 421 offset plus the actual number of bytes read.
383 422
384 If $offset is undefined, then the current file descriptor offset 423 If $offset is undefined, then the current file descriptor offset
… …
441 As native sendfile syscalls (as practically any non-POSIX interface 480 As native sendfile syscalls (as practically any non-POSIX interface
442 hacked together in a hurry to improve benchmark numbers) tend to be 481 hacked together in a hurry to improve benchmark numbers) tend to be
443 rather buggy on many systems, this implementation tries to work 482 rather buggy on many systems, this implementation tries to work
444 around some known bugs in Linux and FreeBSD kernels (probably 483 around some known bugs in Linux and FreeBSD kernels (probably
445 others, too), but that might fail, so you really really should check 484 others, too), but that might fail, so you really really should check
446 the return value of "aio_sendfile" - fewre bytes than expected might 485 the return value of "aio_sendfile" - fewer bytes than expected might
447 have been transferred. 486 have been transferred.
448 487
449 aio_readahead $fh,$offset,$length, $callback->($retval) 488 aio_readahead $fh,$offset,$length, $callback->($retval)
450 "aio_readahead" populates the page cache with data from a file so 489 "aio_readahead" populates the page cache with data from a file so
451 that subsequent reads from that file will not block on disk I/O. The 490 that subsequent reads from that file will not block on disk I/O. The
… …
455 to a page boundary and bytes are read up to the next page boundary 494 to a page boundary and bytes are read up to the next page boundary
456 greater than or equal to (off-set+length). "aio_readahead" does not 495 greater than or equal to (off-set+length). "aio_readahead" does not
457 read beyond the end of the file. The current file offset of the file 496 read beyond the end of the file. The current file offset of the file
458 is left unchanged. 497 is left unchanged.
459 498
460 If that syscall doesn't exist (likely if your OS isn't Linux) it 499 If that syscall doesn't exist (likely if your kernel isn't Linux) it
461 will be emulated by simply reading the data, which would have a 500 will be emulated by simply reading the data, which would have a
462 similar effect. 501 similar effect.
463 502
464 aio_stat $fh_or_path, $callback->($status) 503 aio_stat $fh_or_path, $callback->($status)
465 aio_lstat $fh, $callback->($status) 504 aio_lstat $fh, $callback->($status)
466 Works like perl's "stat" or "lstat" in void context. The callback 505 Works almost exactly like perl's "stat" or "lstat" in void context.
467 will be called after the stat and the results will be available 506 The callback will be called after the stat and the results will be
468 using "stat _" or "-s _" etc... 507 available using "stat _" or "-s _" and other tests (with the
508 exception of "-B" and "-T").
469 509
470 The pathname passed to "aio_stat" must be absolute. See API NOTES, 510 The pathname passed to "aio_stat" must be absolute. See API NOTES,
471 above, for an explanation. 511 above, for an explanation.
472 512
473 Currently, the stats are always 64-bit-stats, i.e. instead of 513 Currently, the stats are always 64-bit-stats, i.e. instead of
… …
481 back on traditional behaviour). 521 back on traditional behaviour).
482 522
483 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", 523 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
484 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", 524 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
485 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". 525 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
526
527 To access higher resolution stat timestamps, see "SUBSECOND STAT
528 TIME ACCESS".
486 529
487 Example: Print the length of /etc/passwd: 530 Example: Print the length of /etc/passwd:
488 531
489 aio_stat "/etc/passwd", sub { 532 aio_stat "/etc/passwd", sub {
490 $_[0] and die "stat failed: $!"; 533 $_[0] and die "stat failed: $!";
… …
532 namemax => 255, 575 namemax => 255,
533 frsize => 1024, 576 frsize => 1024,
534 fsid => 1810 577 fsid => 1810
535 } 578 }
536 579
537 Here is a (likely partial - send me updates!) list of fsid values
538 used by Linux - it is safe to hardcode these when $^O is "linux":
539
540 0x0000adf5 adfs
541 0x0000adff affs
542 0x5346414f afs
543 0x09041934 anon-inode filesystem
544 0x00000187 autofs
545 0x42465331 befs
546 0x1badface bfs
547 0x42494e4d binfmt_misc
548 0x9123683e btrfs
549 0x0027e0eb cgroupfs
550 0xff534d42 cifs
551 0x73757245 coda
552 0x012ff7b7 coh
553 0x28cd3d45 cramfs
554 0x453dcd28 cramfs-wend (wrong endianness)
555 0x64626720 debugfs
556 0x00001373 devfs
557 0x00001cd1 devpts
558 0x0000f15f ecryptfs
559 0x00414a53 efs
560 0x0000137d ext
561 0x0000ef53 ext2/ext3/ext4
562 0x0000ef51 ext2
563 0xf2f52010 f2fs
564 0x00004006 fat
565 0x65735546 fuseblk
566 0x65735543 fusectl
567 0x0bad1dea futexfs
568 0x01161970 gfs2
569 0x47504653 gpfs
570 0x00004244 hfs
571 0xf995e849 hpfs
572 0x00c0ffee hostfs
573 0x958458f6 hugetlbfs
574 0x2bad1dea inotifyfs
575 0x00009660 isofs
576 0x000072b6 jffs2
577 0x3153464a jfs
578 0x6b414653 k-afs
579 0x0bd00bd0 lustre
580 0x0000137f minix
581 0x0000138f minix 30 char names
582 0x00002468 minix v2
583 0x00002478 minix v2 30 char names
584 0x00004d5a minix v3
585 0x19800202 mqueue
586 0x00004d44 msdos
587 0x0000564c novell
588 0x00006969 nfs
589 0x6e667364 nfsd
590 0x00003434 nilfs
591 0x5346544e ntfs
592 0x00009fa1 openprom
593 0x7461636F ocfs2
594 0x00009fa0 proc
595 0x6165676c pstorefs
596 0x0000002f qnx4
597 0x68191122 qnx6
598 0x858458f6 ramfs
599 0x52654973 reiserfs
600 0x00007275 romfs
601 0x67596969 rpc_pipefs
602 0x73636673 securityfs
603 0xf97cff8c selinux
604 0x0000517b smb
605 0x534f434b sockfs
606 0x73717368 squashfs
607 0x62656572 sysfs
608 0x012ff7b6 sysv2
609 0x012ff7b5 sysv4
610 0x01021994 tmpfs
611 0x15013346 udf
612 0x00011954 ufs
613 0x54190100 ufs byteswapped
614 0x00009fa2 usbdevfs
615 0x01021997 v9fs
616 0xa501fcf5 vxfs
617 0xabba1974 xenfs
618 0x012ff7b4 xenix
619 0x58465342 xfs
620 0x012fd16d xia
621
622 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 580 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
623 Works like perl's "utime" function (including the special case of 581 Works like perl's "utime" function (including the special case of
624 $atime and $mtime being undef). Fractional times are supported if 582 $atime and $mtime being undef). Fractional times are supported if
625 the underlying syscalls support them. 583 the underlying syscalls support them.
626 584
627 When called with a pathname, uses utimes(2) if available, otherwise 585 When called with a pathname, uses utimensat(2) or utimes(2) if
628 utime(2). If called on a file descriptor, uses futimes(2) if 586 available, otherwise utime(2). If called on a file descriptor, uses
629 available, otherwise returns ENOSYS, so this is not portable. 587 futimens(2) or futimes(2) if available, otherwise returns ENOSYS, so
588 this is not portable.
630 589
631 Examples: 590 Examples:
632 591
633 # set atime and mtime to current time (basically touch(1)): 592 # set atime and mtime to current time (basically touch(1)):
634 aio_utime "path", undef, undef; 593 aio_utime "path", undef, undef;
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657 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate 616 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
658 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE | 617 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
659 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range. 618 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
660 619
661 IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range 620 IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range
662 (without leaving a hole) and "FALLOC_FL_ZERO_RANGE", to zero a range 621 (without leaving a hole), "FALLOC_FL_ZERO_RANGE", to zero a range,
622 "FALLOC_FL_INSERT_RANGE" to insert a range and
623 "FALLOC_FL_UNSHARE_RANGE" to unshare shared blocks (see your
663 (see your fallocate(2) manpage). 624 fallocate(2) manpage).
664 625
665 The file system block size used by "fallocate" is presumably the 626 The file system block size used by "fallocate" is presumably the
666 "f_bsize" returned by "statvfs". 627 "f_bsize" returned by "statvfs", but different filesystems and
628 filetypes can dictate other limitations.
667 629
668 If "fallocate" isn't available or cannot be emulated (currently no 630 If "fallocate" isn't available or cannot be emulated (currently no
669 emulation will be attempted), passes -1 and sets $! to "ENOSYS". 631 emulation will be attempted), passes -1 and sets $! to "ENOSYS".
670 632
671 aio_chmod $fh_or_path, $mode, $callback->($status) 633 aio_chmod $fh_or_path, $mode, $callback->($status)
… …
715 677
716 On systems that support the AIO::WD working directory abstraction 678 On systems that support the AIO::WD working directory abstraction
717 natively, the case "[$wd, "."]" as $srcpath is specialcased - 679 natively, the case "[$wd, "."]" as $srcpath is specialcased -
718 instead of failing, "rename" is called on the absolute path of $wd. 680 instead of failing, "rename" is called on the absolute path of $wd.
719 681
682 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
683 Basically a version of "aio_rename" with an additional $flags
684 argument. Calling this with "$flags=0" is the same as calling
685 "aio_rename".
686
687 Non-zero flags are currently only supported on GNU/Linux systems
688 that support renameat2. Other systems fail with "ENOSYS" in this
689 case.
690
691 The following constants are available (missing ones are, as usual
692 0), see renameat2(2) for details:
693
694 "IO::AIO::RENAME_NOREPLACE", "IO::AIO::RENAME_EXCHANGE" and
695 "IO::AIO::RENAME_WHITEOUT".
696
720 aio_mkdir $pathname, $mode, $callback->($status) 697 aio_mkdir $pathname, $mode, $callback->($status)
721 Asynchronously mkdir (create) a directory and call the callback with 698 Asynchronously mkdir (create) a directory and call the callback with
722 the result code. $mode will be modified by the umask at the time the 699 the result code. $mode will be modified by the umask at the time the
723 request is executed, so do not change your umask. 700 request is executed, so do not change your umask.
724 701
… …
746 The flags are a combination of the following constants, ORed 723 The flags are a combination of the following constants, ORed
747 together (the flags will also be passed to the callback, possibly 724 together (the flags will also be passed to the callback, possibly
748 modified): 725 modified):
749 726
750 IO::AIO::READDIR_DENTS 727 IO::AIO::READDIR_DENTS
751 When this flag is off, then the callback gets an arrayref 728 Normally the callback gets an arrayref consisting of names only
752 consisting of names only (as with "aio_readdir"), otherwise it 729 (as with "aio_readdir"). If this flag is set, then the callback
753 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each 730 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
754 describing a single directory entry in more detail. 731 describing a single directory entry in more detail:
755 732
756 $name is the name of the entry. 733 $name is the name of the entry.
757 734
758 $type is one of the "IO::AIO::DT_xxx" constants: 735 $type is one of the "IO::AIO::DT_xxx" constants:
759 736
760 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", 737 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",
761 "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG", 738 "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",
762 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT". 739 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
763 740
764 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If 741 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If
765 you need to know, you have to run stat yourself. Also, for speed 742 you need to know, you have to run stat yourself. Also, for
766 reasons, the $type scalars are read-only: you can not modify 743 speed/memory reasons, the $type scalars are read-only: you must
767 them. 744 not modify them.
768 745
769 $inode is the inode number (which might not be exact on systems 746 $inode is the inode number (which might not be exact on systems
770 with 64 bit inode numbers and 32 bit perls). This field has 747 with 64 bit inode numbers and 32 bit perls). This field has
771 unspecified content on systems that do not deliver the inode 748 unspecified content on systems that do not deliver the inode
772 information. 749 information.
… …
784 of which names with short names are tried first. 761 of which names with short names are tried first.
785 762
786 IO::AIO::READDIR_STAT_ORDER 763 IO::AIO::READDIR_STAT_ORDER
787 When this flag is set, then the names will be returned in an 764 When this flag is set, then the names will be returned in an
788 order suitable for stat()'ing each one. That is, when you plan 765 order suitable for stat()'ing each one. That is, when you plan
789 to stat() all files in the given directory, then the returned 766 to stat() most or all files in the given directory, then the
790 order will likely be fastest. 767 returned order will likely be faster.
791 768
792 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are 769 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
793 specified, then the likely dirs come first, resulting in a less 770 specified, then the likely dirs come first, resulting in a less
794 optimal stat order. 771 optimal stat order for stat'ing all entries, but likely a more
772 optimal order for finding subdirectories.
795 773
796 IO::AIO::READDIR_FOUND_UNKNOWN 774 IO::AIO::READDIR_FOUND_UNKNOWN
797 This flag should not be set when calling "aio_readdirx". 775 This flag should not be set when calling "aio_readdirx".
798 Instead, it is being set by "aio_readdirx", when any of the 776 Instead, it is being set by "aio_readdirx", when any of the
799 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this 777 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this
800 flag therefore indicates that all $type's are known, which can 778 flag therefore indicates that all $type's are known, which can
801 be used to speed up some algorithms. 779 be used to speed up some algorithms.
802 780
781 aio_slurp $pathname, $offset, $length, $data, $callback->($status)
782 Opens, reads and closes the given file. The data is put into $data,
783 which is resized as required.
784
785 If $offset is negative, then it is counted from the end of the file.
786
787 If $length is zero, then the remaining length of the file is used.
788 Also, in this case, the same limitations to modifying $data apply as
789 when IO::AIO::mmap is used, i.e. it must only be modified in-place
790 with "substr". If the size of the file is known, specifying a
791 non-zero $length results in a performance advantage.
792
793 This request is similar to the older "aio_load" request, but since
794 it is a single request, it might be more efficient to use.
795
796 Example: load /etc/passwd into $passwd.
797
798 my $passwd;
799 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
800 $_[0] >= 0
801 or die "/etc/passwd: $!\n";
802
803 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
804 print $passwd;
805 };
806 IO::AIO::flush;
807
803 aio_load $pathname, $data, $callback->($status) 808 aio_load $pathname, $data, $callback->($status)
804 This is a composite request that tries to fully load the given file 809 This is a composite request that tries to fully load the given file
805 into memory. Status is the same as with aio_read. 810 into memory. Status is the same as with aio_read.
811
812 Using "aio_slurp" might be more efficient, as it is a single
813 request.
806 814
807 aio_copy $srcpath, $dstpath, $callback->($status) 815 aio_copy $srcpath, $dstpath, $callback->($status)
808 Try to copy the *file* (directories not supported as either source 816 Try to copy the *file* (directories not supported as either source
809 or destination) from $srcpath to $dstpath and call the callback with 817 or destination) from $srcpath to $dstpath and call the callback with
810 a status of 0 (ok) or -1 (error, see $!). 818 a status of 0 (ok) or -1 (error, see $!).
819
820 Existing destination files will be truncated.
811 821
812 This is a composite request that creates the destination file with 822 This is a composite request that creates the destination file with
813 mode 0200 and copies the contents of the source file into it using 823 mode 0200 and copies the contents of the source file into it using
814 "aio_sendfile", followed by restoring atime, mtime, access mode and 824 "aio_sendfile", followed by restoring atime, mtime, access mode and
815 uid/gid, in that order. 825 uid/gid, in that order.
… …
832 to efficiently separate the entries of directory $path into two sets 842 to efficiently separate the entries of directory $path into two sets
833 of names, directories you can recurse into (directories), and ones 843 of names, directories you can recurse into (directories), and ones
834 you cannot recurse into (everything else, including symlinks to 844 you cannot recurse into (everything else, including symlinks to
835 directories). 845 directories).
836 846
837 "aio_scandir" is a composite request that creates of many sub 847 "aio_scandir" is a composite request that generates many sub
838 requests_ $maxreq specifies the maximum number of outstanding aio 848 requests. $maxreq specifies the maximum number of outstanding aio
839 requests that this function generates. If it is "<= 0", then a 849 requests that this function generates. If it is "<= 0", then a
840 suitable default will be chosen (currently 4). 850 suitable default will be chosen (currently 4).
841 851
842 On error, the callback is called without arguments, otherwise it 852 On error, the callback is called without arguments, otherwise it
843 receives two array-refs with path-relative entry names. 853 receives two array-refs with path-relative entry names.
… …
908 So in general, you should only use these calls for things that do 918 So in general, you should only use these calls for things that do
909 (filesystem) I/O, not for things that wait for other events 919 (filesystem) I/O, not for things that wait for other events
910 (network, other processes), although if you are careful and know 920 (network, other processes), although if you are careful and know
911 what you are doing, you still can. 921 what you are doing, you still can.
912 922
923 The following constants are available and can be used for normal
924 "ioctl" and "fcntl" as well (missing ones are, as usual 0):
925
926 "F_DUPFD_CLOEXEC",
927
928 "F_OFD_GETLK", "F_OFD_SETLK", "F_OFD_GETLKW",
929
930 "FIFREEZE", "FITHAW", "FITRIM", "FICLONE", "FICLONERANGE",
931 "FIDEDUPERANGE".
932
933 "F_ADD_SEALS", "F_GET_SEALS", "F_SEAL_SEAL", "F_SEAL_SHRINK",
934 "F_SEAL_GROW" and "F_SEAL_WRITE".
935
936 "FS_IOC_GETFLAGS", "FS_IOC_SETFLAGS", "FS_IOC_GETVERSION",
937 "FS_IOC_SETVERSION", "FS_IOC_FIEMAP".
938
939 "FS_IOC_FSGETXATTR", "FS_IOC_FSSETXATTR",
940 "FS_IOC_SET_ENCRYPTION_POLICY", "FS_IOC_GET_ENCRYPTION_PWSALT",
941 "FS_IOC_GET_ENCRYPTION_POLICY", "FS_KEY_DESCRIPTOR_SIZE".
942
943 "FS_SECRM_FL", "FS_UNRM_FL", "FS_COMPR_FL", "FS_SYNC_FL",
944 "FS_IMMUTABLE_FL", "FS_APPEND_FL", "FS_NODUMP_FL", "FS_NOATIME_FL",
945 "FS_DIRTY_FL", "FS_COMPRBLK_FL", "FS_NOCOMP_FL", "FS_ENCRYPT_FL",
946 "FS_BTREE_FL", "FS_INDEX_FL", "FS_JOURNAL_DATA_FL", "FS_NOTAIL_FL",
947 "FS_DIRSYNC_FL", "FS_TOPDIR_FL", "FS_FL_USER_MODIFIABLE".
948
949 "FS_XFLAG_REALTIME", "FS_XFLAG_PREALLOC", "FS_XFLAG_IMMUTABLE",
950 "FS_XFLAG_APPEND", "FS_XFLAG_SYNC", "FS_XFLAG_NOATIME",
951 "FS_XFLAG_NODUMP", "FS_XFLAG_RTINHERIT", "FS_XFLAG_PROJINHERIT",
952 "FS_XFLAG_NOSYMLINKS", "FS_XFLAG_EXTSIZE", "FS_XFLAG_EXTSZINHERIT",
953 "FS_XFLAG_NODEFRAG", "FS_XFLAG_FILESTREAM", "FS_XFLAG_DAX",
954 "FS_XFLAG_HASATTR",
955
913 aio_sync $callback->($status) 956 aio_sync $callback->($status)
914 Asynchronously call sync and call the callback when finished. 957 Asynchronously call sync and call the callback when finished.
915 958
916 aio_fsync $fh, $callback->($status) 959 aio_fsync $fh, $callback->($status)
917 Asynchronously call fsync on the given filehandle and call the 960 Asynchronously call fsync on the given filehandle and call the
… …
953 Future versions of this function might fall back to other methods 996 Future versions of this function might fall back to other methods
954 when "fsync" on the directory fails (such as calling "sync"). 997 when "fsync" on the directory fails (such as calling "sync").
955 998
956 Passes 0 when everything went ok, and -1 on error. 999 Passes 0 when everything went ok, and -1 on error.
957 1000
958 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, 1001 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC,
959 $callback->($status) 1002 $callback->($status)
960 This is a rather advanced IO::AIO call, which only works on 1003 This is a rather advanced IO::AIO call, which only works on
961 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it 1004 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
962 also works on data scalars managed by the Sys::Mmap or Mmap modules, 1005 also works on data scalars managed by the Sys::Mmap or Mmap modules,
963 note that the scalar must only be modified in-place while an aio 1006 note that the scalar must only be modified in-place while an aio
… …
965 1008
966 It calls the "msync" function of your OS, if available, with the 1009 It calls the "msync" function of your OS, if available, with the
967 memory area starting at $offset in the string and ending $length 1010 memory area starting at $offset in the string and ending $length
968 bytes later. If $length is negative, counts from the end, and if 1011 bytes later. If $length is negative, counts from the end, and if
969 $length is "undef", then it goes till the end of the string. The 1012 $length is "undef", then it goes till the end of the string. The
970 flags can be a combination of "IO::AIO::MS_ASYNC", 1013 flags can be either "IO::AIO::MS_ASYNC" or "IO::AIO::MS_SYNC", plus
971 "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC". 1014 an optional "IO::AIO::MS_INVALIDATE".
972 1015
973 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, 1016 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
974 $callback->($status) 1017 $callback->($status)
975 This is a rather advanced IO::AIO call, which works best on 1018 This is a rather advanced IO::AIO call, which works best on
976 mmap(2)ed scalars. 1019 mmap(2)ed scalars.
… …
1007 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1050 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1008 aio_mlock $data; # mlock in background 1051 aio_mlock $data; # mlock in background
1009 1052
1010 aio_mlockall $flags, $callback->($status) 1053 aio_mlockall $flags, $callback->($status)
1011 Calls the "mlockall" function with the given $flags (a combination 1054 Calls the "mlockall" function with the given $flags (a combination
1012 of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE"). 1055 of "IO::AIO::MCL_CURRENT", "IO::AIO::MCL_FUTURE" and
1056 "IO::AIO::MCL_ONFAULT").
1013 1057
1014 On systems that do not implement "mlockall", this function returns 1058 On systems that do not implement "mlockall", this function returns
1015 -1 and sets errno to "ENOSYS". 1059 -1 and sets errno to "ENOSYS". Similarly, flag combinations not
1060 supported by the system result in a return value of -1 with errno
1061 being set to "EINVAL".
1016 1062
1017 Note that the corresponding "munlockall" is synchronous and is 1063 Note that the corresponding "munlockall" is synchronous and is
1018 documented under "MISCELLANEOUS FUNCTIONS". 1064 documented under "MISCELLANEOUS FUNCTIONS".
1019 1065
1020 Example: asynchronously lock all current and future pages into 1066 Example: asynchronously lock all current and future pages into
… …
1062 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", 1108 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
1063 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", 1109 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
1064 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" 1110 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
1065 or "IO::AIO::FIEMAP_EXTENT_SHARED". 1111 or "IO::AIO::FIEMAP_EXTENT_SHARED".
1066 1112
1067 At the time of this writing (Linux 3.2), this requets is unreliable 1113 At the time of this writing (Linux 3.2), this request is unreliable
1068 unless $count is "undef", as the kernel has all sorts of bugs 1114 unless $count is "undef", as the kernel has all sorts of bugs
1069 preventing it to return all extents of a range for files with large 1115 preventing it to return all extents of a range for files with a
1070 number of extents. The code works around all these issues if $count 1116 large number of extents. The code (only) works around all these
1071 is undef. 1117 issues if $count is "undef".
1072 1118
1073 aio_group $callback->(...) 1119 aio_group $callback->(...)
1074 This is a very special aio request: Instead of doing something, it 1120 This is a very special aio request: Instead of doing something, it
1075 is a container for other aio requests, which is useful if you want 1121 is a container for other aio requests, which is useful if you want
1076 to bundle many requests into a single, composite, request with a 1122 to bundle many requests into a single, composite, request with a
… …
1185 There are some caveats: when directories get renamed (or deleted), the 1231 There are some caveats: when directories get renamed (or deleted), the
1186 pathname string doesn't change, so will point to the new directory (or 1232 pathname string doesn't change, so will point to the new directory (or
1187 nowhere at all), while the directory fd, if available on the system, 1233 nowhere at all), while the directory fd, if available on the system,
1188 will still point to the original directory. Most functions accepting a 1234 will still point to the original directory. Most functions accepting a
1189 pathname will use the directory fd on newer systems, and the string on 1235 pathname will use the directory fd on newer systems, and the string on
1190 older systems. Some functions (such as realpath) will always rely on the 1236 older systems. Some functions (such as "aio_realpath") will always rely
1191 string form of the pathname. 1237 on the string form of the pathname.
1192 1238
1193 So this functionality is mainly useful to get some protection against 1239 So this functionality is mainly useful to get some protection against
1194 "chdir", to easily get an absolute path out of a relative path for 1240 "chdir", to easily get an absolute path out of a relative path for
1195 future reference, and to speed up doing many operations in the same 1241 future reference, and to speed up doing many operations in the same
1196 directory (e.g. when stat'ing all files in a directory). 1242 directory (e.g. when stat'ing all files in a directory).
… …
1209 fails the request with "ENOENT", there is often no need for error 1255 fails the request with "ENOENT", there is often no need for error
1210 checking in the "aio_wd" callback, as future requests using the 1256 checking in the "aio_wd" callback, as future requests using the
1211 value will fail in the expected way. 1257 value will fail in the expected way.
1212 1258
1213 IO::AIO::CWD 1259 IO::AIO::CWD
1214 This is a compiletime constant (object) that represents the process 1260 This is a compile time constant (object) that represents the process
1215 current working directory. 1261 current working directory.
1216 1262
1217 Specifying this object as working directory object for a pathname is 1263 Specifying this object as working directory object for a pathname is
1218 as if the pathname would be specified directly, without a directory 1264 as if the pathname would be specified directly, without a directory
1219 object. For example, these calls are functionally identical: 1265 object. For example, these calls are functionally identical:
… …
1444 Strictly equivalent to: 1490 Strictly equivalent to:
1445 1491
1446 IO::AIO::poll_wait, IO::AIO::poll_cb 1492 IO::AIO::poll_wait, IO::AIO::poll_cb
1447 while IO::AIO::nreqs; 1493 while IO::AIO::nreqs;
1448 1494
1495 This function can be useful at program aborts, to make sure
1496 outstanding I/O has been done ("IO::AIO" uses an "END" block which
1497 already calls this function on normal exits), or when you are merely
1498 using "IO::AIO" for its more advanced functions, rather than for
1499 async I/O, e.g.:
1500
1501 my ($dirs, $nondirs);
1502 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1503 IO::AIO::flush;
1504 # $dirs, $nondirs are now set
1505
1449 IO::AIO::max_poll_reqs $nreqs 1506 IO::AIO::max_poll_reqs $nreqs
1450 IO::AIO::max_poll_time $seconds 1507 IO::AIO::max_poll_time $seconds
1451 These set the maximum number of requests (default 0, meaning 1508 These set the maximum number of requests (default 0, meaning
1452 infinity) that are being processed by "IO::AIO::poll_cb" in one 1509 infinity) that are being processed by "IO::AIO::poll_cb" in one
1453 call, respectively the maximum amount of time (default 0, meaning 1510 call, respectively the maximum amount of time (default 0, meaning
… …
1542 no longer exceeded. 1599 no longer exceeded.
1543 1600
1544 In other words, this setting does not enforce a queue limit, but can 1601 In other words, this setting does not enforce a queue limit, but can
1545 be used to make poll functions block if the limit is exceeded. 1602 be used to make poll functions block if the limit is exceeded.
1546 1603
1547 This is a very bad function to use in interactive programs because 1604 This is a bad function to use in interactive programs because it
1548 it blocks, and a bad way to reduce concurrency because it is 1605 blocks, and a bad way to reduce concurrency because it is inexact.
1549 inexact: Better use an "aio_group" together with a feed callback. 1606 If you need to issue many requests without being able to call a poll
1607 function on demand, it is better to use an "aio_group" together with
1608 a feed callback.
1550 1609
1551 Its main use is in scripts without an event loop - when you want to 1610 Its main use is in scripts without an event loop - when you want to
1552 stat a lot of files, you can write somehting like this: 1611 stat a lot of files, you can write something like this:
1553 1612
1554 IO::AIO::max_outstanding 32; 1613 IO::AIO::max_outstanding 32;
1555 1614
1556 for my $path (...) { 1615 for my $path (...) {
1557 aio_stat $path , ...; 1616 aio_stat $path , ...;
… …
1559 } 1618 }
1560 1619
1561 IO::AIO::flush; 1620 IO::AIO::flush;
1562 1621
1563 The call to "poll_cb" inside the loop will normally return 1622 The call to "poll_cb" inside the loop will normally return
1564 instantly, but as soon as more thna 32 reqeusts are in-flight, it 1623 instantly, allowing the loop to progress, but as soon as more than
1565 will block until some requests have been handled. This keeps the 1624 32 requests are in-flight, it will block until some requests have
1566 loop from pushing a large number of "aio_stat" requests onto the 1625 been handled. This keeps the loop from pushing a large number of
1567 queue. 1626 "aio_stat" requests onto the queue (which, with many paths to stat,
1627 can use up a lot of memory).
1568 1628
1569 The default value for "max_outstanding" is very large, so there is 1629 The default value for "max_outstanding" is very large, so there is
1570 no practical limit on the number of outstanding requests. 1630 no practical limit on the number of outstanding requests.
1571 1631
1572 STATISTICAL INFORMATION 1632 STATISTICAL INFORMATION
… …
1586 1646
1587 IO::AIO::npending 1647 IO::AIO::npending
1588 Returns the number of requests currently in the pending state 1648 Returns the number of requests currently in the pending state
1589 (executed, but not yet processed by poll_cb). 1649 (executed, but not yet processed by poll_cb).
1590 1650
1651 SUBSECOND STAT TIME ACCESS
1652 Both "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" functions can
1653 generally find access/modification and change times with subsecond time
1654 accuracy of the system supports it, but perl's built-in functions only
1655 return the integer part.
1656
1657 The following functions return the timestamps of the most recent stat
1658 with subsecond precision on most systems and work both after
1659 "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" calls. Their return
1660 value is only meaningful after a successful "stat"/"lstat" call, or
1661 during/after a successful "aio_stat"/"aio_lstat" callback.
1662
1663 This is similar to the Time::HiRes "stat" functions, but can return full
1664 resolution without rounding and work with standard perl "stat",
1665 alleviating the need to call the special "Time::HiRes" functions, which
1666 do not act like their perl counterparts.
1667
1668 On operating systems or file systems where subsecond time resolution is
1669 not supported or could not be detected, a fractional part of 0 is
1670 returned, so it is always safe to call these functions.
1671
1672 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime,
1673 IO::AIO::st_btime
1674 Return the access, modication, change or birth time, respectively,
1675 including fractional part. Due to the limited precision of floating
1676 point, the accuracy on most platforms is only a bit better than
1677 milliseconds for times around now - see the *nsec* function family,
1678 below, for full accuracy.
1679
1680 File birth time is only available when the OS and perl support it
1681 (on FreeBSD and NetBSD at the time of this writing, although support
1682 is adaptive, so if your OS/perl gains support, IO::AIO can take
1683 advantage of it). On systems where it isn't available, 0 is
1684 currently returned, but this might change to "undef" in a future
1685 version.
1686
1687 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
1688 Returns access, modification, change and birth time all in one go,
1689 and maybe more times in the future version.
1690
1691 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec,
1692 IO::AIO::st_ctimensec, IO::AIO::st_btimensec
1693 Return the fractional access, modifcation, change or birth time, in
1694 nanoseconds, as an integer in the range 0 to 999999999.
1695
1696 Note that no accessors are provided for access, modification and
1697 change times - you need to get those from "stat _" if required ("int
1698 IO::AIO::st_atime" and so on will *not* generally give you the
1699 correct value).
1700
1701 $seconds = IO::AIO::st_btimesec
1702 The (integral) seconds part of the file birth time, if available.
1703
1704 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
1705 Like the functions above, but returns all four times in one go (and
1706 maybe more in future versions).
1707
1708 $counter = IO::AIO::st_gen
1709 Returns the generation counter (in practice this is just a random
1710 number) of the file. This is only available on platforms which have
1711 this member in their "struct stat" (most BSDs at the time of this
1712 writing) and generally only to the root usert. If unsupported, 0 is
1713 returned, but this might change to "undef" in a future version.
1714
1715 Example: print the high resolution modification time of /etc, using
1716 "stat", and "IO::AIO::aio_stat".
1717
1718 if (stat "/etc") {
1719 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
1720 }
1721
1722 IO::AIO::aio_stat "/etc", sub {
1723 $_[0]
1724 and return;
1725
1726 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
1727 };
1728
1729 IO::AIO::flush;
1730
1731 Output of the awbove on my system, showing reduced and full accuracy:
1732
1733 stat(/etc) mtime: 1534043702.020808
1734 aio_stat(/etc) mtime: 1534043702.020807792
1735
1591 MISCELLANEOUS FUNCTIONS 1736 MISCELLANEOUS FUNCTIONS
1592 IO::AIO implements some functions that are useful when you want to use 1737 IO::AIO implements some functions that are useful when you want to use
1593 some "Advanced I/O" function not available to in Perl, without going the 1738 some "Advanced I/O" function not available to in Perl, without going the
1594 "Asynchronous I/O" route. Many of these have an asynchronous "aio_*" 1739 "Asynchronous I/O" route. Many of these have an asynchronous "aio_*"
1595 counterpart. 1740 counterpart.
1741
1742 $retval = IO::AIO::fexecve $fh, $argv, $envp
1743 A more-or-less direct equivalent to the POSIX "fexecve" functions,
1744 which allows you to specify the program to be executed via a file
1745 descriptor (or handle). Returns -1 and sets errno to "ENOSYS" if not
1746 available.
1747
1748 $numfd = IO::AIO::get_fdlimit
1749 Tries to find the current file descriptor limit and returns it, or
1750 "undef" and sets $! in case of an error. The limit is one larger
1751 than the highest valid file descriptor number.
1752
1753 IO::AIO::min_fdlimit [$numfd]
1754 Try to increase the current file descriptor limit(s) to at least
1755 $numfd by changing the soft or hard file descriptor resource limit.
1756 If $numfd is missing, it will try to set a very high limit, although
1757 this is not recommended when you know the actual minimum that you
1758 require.
1759
1760 If the limit cannot be raised enough, the function makes a
1761 best-effort attempt to increase the limit as much as possible, using
1762 various tricks, while still failing. You can query the resulting
1763 limit using "IO::AIO::get_fdlimit".
1764
1765 If an error occurs, returns "undef" and sets $!, otherwise returns
1766 true.
1596 1767
1597 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1768 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1598 Calls the "eio_sendfile_sync" function, which is like 1769 Calls the "eio_sendfile_sync" function, which is like
1599 "aio_sendfile", but is blocking (this makes most sense if you know 1770 "aio_sendfile", but is blocking (this makes most sense if you know
1600 the input data is likely cached already and the output filehandle is 1771 the input data is likely cached already and the output filehandle is
… …
1617 details). The following advice constants are available: 1788 details). The following advice constants are available:
1618 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", 1789 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1619 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", 1790 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1620 "IO::AIO::MADV_DONTNEED". 1791 "IO::AIO::MADV_DONTNEED".
1621 1792
1793 If $offset is negative, counts from the end. If $length is negative,
1794 the remaining length of the $scalar is used. If possible, $length
1795 will be reduced to fit into the $scalar.
1796
1622 On systems that do not implement "posix_madvise", this function 1797 On systems that do not implement "posix_madvise", this function
1623 returns ENOSYS, otherwise the return value of "posix_madvise". 1798 returns ENOSYS, otherwise the return value of "posix_madvise".
1624 1799
1625 IO::AIO::mprotect $scalar, $offset, $len, $protect 1800 IO::AIO::mprotect $scalar, $offset, $len, $protect
1626 Simply calls the "mprotect" function on the preferably AIO::mmap'ed 1801 Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1627 $scalar (see its manpage for details). The following protect 1802 $scalar (see its manpage for details). The following protect
1628 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", 1803 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1629 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". 1804 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1630 1805
1806 If $offset is negative, counts from the end. If $length is negative,
1807 the remaining length of the $scalar is used. If possible, $length
1808 will be reduced to fit into the $scalar.
1809
1631 On systems that do not implement "mprotect", this function returns 1810 On systems that do not implement "mprotect", this function returns
1632 ENOSYS, otherwise the return value of "mprotect". 1811 ENOSYS, otherwise the return value of "mprotect".
1633 1812
1634 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1813 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1635 Memory-maps a file (or anonymous memory range) and attaches it to 1814 Memory-maps a file (or anonymous memory range) and attaches it to
1636 the given $scalar, which will act like a string scalar. Returns true 1815 the given $scalar, which will act like a string scalar. Returns true
1637 on success, and false otherwise. 1816 on success, and false otherwise.
1638 1817
1818 The scalar must exist, but its contents do not matter - this means
1819 you cannot use a nonexistant array or hash element. When in doubt,
1820 "undef" the scalar first.
1821
1639 The only operations allowed on the scalar are "substr"/"vec" that 1822 The only operations allowed on the mmapped scalar are
1640 don't change the string length, and most read-only operations such 1823 "substr"/"vec", which don't change the string length, and most
1641 as copying it or searching it with regexes and so on. 1824 read-only operations such as copying it or searching it with regexes
1825 and so on.
1642 1826
1643 Anything else is unsafe and will, at best, result in memory leaks. 1827 Anything else is unsafe and will, at best, result in memory leaks.
1644 1828
1645 The memory map associated with the $scalar is automatically removed 1829 The memory map associated with the $scalar is automatically removed
1646 when the $scalar is destroyed, or when the "IO::AIO::mmap" or 1830 when the $scalar is undef'd or destroyed, or when the
1647 "IO::AIO::munmap" functions are called. 1831 "IO::AIO::mmap" or "IO::AIO::munmap" functions are called on it.
1648 1832
1649 This calls the "mmap"(2) function internally. See your system's 1833 This calls the "mmap"(2) function internally. See your system's
1650 manual page for details on the $length, $prot and $flags parameters. 1834 manual page for details on the $length, $prot and $flags parameters.
1651 1835
1652 The $length must be larger than zero and smaller than the actual 1836 The $length must be larger than zero and smaller than the actual
… …
1661 not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to 1845 not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to
1662 "MAP_ANON" if your system only provides this constant), 1846 "MAP_ANON" if your system only provides this constant),
1663 "IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE", 1847 "IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE",
1664 "IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK", 1848 "IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK",
1665 "IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN", 1849 "IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN",
1666 "IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB" or 1850 "IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_STACK",
1667 "IO::AIO::MAP_STACK". 1851 "IO::AIO::MAP_FIXED_NOREPLACE", "IO::AIO::MAP_SHARED_VALIDATE",
1852 "IO::AIO::MAP_SYNC" or "IO::AIO::MAP_UNINITIALIZED".
1668 1853
1669 If $fh is "undef", then a file descriptor of -1 is passed. 1854 If $fh is "undef", then a file descriptor of -1 is passed.
1670 1855
1671 $offset is the offset from the start of the file - it generally must 1856 $offset is the offset from the start of the file - it generally must
1672 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. 1857 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
… …
1684 1869
1685 my $fast_md5 = md5 $data; 1870 my $fast_md5 = md5 $data;
1686 1871
1687 IO::AIO::munmap $scalar 1872 IO::AIO::munmap $scalar
1688 Removes a previous mmap and undefines the $scalar. 1873 Removes a previous mmap and undefines the $scalar.
1874
1875 IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[,
1876 $new_address = 0]
1877 Calls the Linux-specific mremap(2) system call. The $scalar must
1878 have been mapped by "IO::AIO::mmap", and $flags must currently
1879 either be 0 or "IO::AIO::MREMAP_MAYMOVE".
1880
1881 Returns true if successful, and false otherwise. If the underlying
1882 mmapped region has changed address, then the true value has the
1883 numerical value 1, otherwise it has the numerical value 0:
1884
1885 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
1886 or die "mremap: $!";
1887
1888 if ($success*1) {
1889 warn "scalar has chanegd address in memory\n";
1890 }
1891
1892 "IO::AIO::MREMAP_FIXED" and the $new_address argument are currently
1893 implemented, but not supported and might go away in a future
1894 version.
1895
1896 On systems where this call is not supported or is not emulated, this
1897 call returns falls and sets $! to "ENOSYS".
1898
1899 IO::AIO::mlockall $flags
1900 Calls the "eio_mlockall_sync" function, which is like
1901 "aio_mlockall", but is blocking.
1689 1902
1690 IO::AIO::munlock $scalar, $offset = 0, $length = undef 1903 IO::AIO::munlock $scalar, $offset = 0, $length = undef
1691 Calls the "munlock" function, undoing the effects of a previous 1904 Calls the "munlock" function, undoing the effects of a previous
1692 "aio_mlock" call (see its description for details). 1905 "aio_mlock" call (see its description for details).
1693 1906
1694 IO::AIO::munlockall 1907 IO::AIO::munlockall
1695 Calls the "munlockall" function. 1908 Calls the "munlockall" function.
1696 1909
1697 On systems that do not implement "munlockall", this function returns 1910 On systems that do not implement "munlockall", this function returns
1698 ENOSYS, otherwise the return value of "munlockall". 1911 ENOSYS, otherwise the return value of "munlockall".
1912
1913 $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
1914 Uses the GNU/Linux accept4(2) syscall, if available, to accept a
1915 socket and return the new file handle on success, or sets $! and
1916 returns "undef" on error.
1917
1918 The remote name of the new socket will be stored in $sockaddr, which
1919 will be extended to allow for at least $sockaddr_maxlen octets. If
1920 the socket name does not fit into $sockaddr_maxlen octets, this is
1921 signaled by returning a longer string in $sockaddr, which might or
1922 might not be truncated.
1923
1924 To accept name-less sockets, use "undef" for $sockaddr and 0 for
1925 $sockaddr_maxlen.
1926
1927 The main reasons to use this syscall rather than portable accept(2)
1928 are that you can specify "SOCK_NONBLOCK" and/or "SOCK_CLOEXEC" flags
1929 and you can accept name-less sockets by specifying 0 for
1930 $sockaddr_maxlen, which is sadly not possible with perl's interface
1931 to "accept".
1699 1932
1700 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags 1933 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1701 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or 1934 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1702 $w_off are "undef", then "NULL" is passed for these, otherwise they 1935 $w_off are "undef", then "NULL" is passed for these, otherwise they
1703 should be the file offset. 1936 should be the file offset.
… …
1738 1971
1739 Please refer to pipe2(2) for more info on the $flags, but at the 1972 Please refer to pipe2(2) for more info on the $flags, but at the
1740 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK" 1973 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"
1741 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were 1974 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
1742 supported. 1975 supported.
1976
1977 Example: create a pipe race-free w.r.t. threads and fork:
1978
1979 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
1980 or die "pipe2: $!\n";
1981
1982 $fh = IO::AIO::memfd_create $pathname[, $flags]
1983 This is a direct interface to the Linux memfd_create(2) system call.
1984 The (unhelpful) default for $flags is 0, but your default should be
1985 "IO::AIO::MFD_CLOEXEC".
1986
1987 On success, the new memfd filehandle is returned, otherwise returns
1988 "undef". If the memfd_create syscall is missing, fails with
1989 "ENOSYS".
1990
1991 Please refer to memfd_create(2) for more info on this call.
1992
1993 The following $flags values are available: "IO::AIO::MFD_CLOEXEC",
1994 "IO::AIO::MFD_ALLOW_SEALING", "IO::AIO::MFD_HUGETLB",
1995 "IO::AIO::MFD_HUGETLB_2MB" and "IO::AIO::MFD_HUGETLB_1GB".
1996
1997 Example: create a new memfd.
1998
1999 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2000 or die "memfd_create: $!\n";
2001
2002 $fh = IO::AIO::pidfd_open $pid[, $flags]
2003 This is an interface to the Linux pidfd_open(2) system call. The
2004 default for $flags is 0.
2005
2006 On success, a new pidfd filehandle is returned (that is already set
2007 to close-on-exec), otherwise returns "undef". If the syscall is
2008 missing, fails with "ENOSYS".
2009
2010 Example: open pid 6341 as pidfd.
2011
2012 my $fh = IO::AIO::pidfd_open 6341
2013 or die "pidfd_open: $!\n";
2014
2015 $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[,
2016 $flags]]
2017 This is an interface to the Linux pidfd_send_signal system call. The
2018 default for $siginfo is "undef" and the default for $flags is 0.
2019
2020 Returns the system call status. If the syscall is missing, fails
2021 with "ENOSYS".
2022
2023 When specified, $siginfo must be a reference to a hash with one or
2024 more of the following members:
2025
2026 code - the "si_code" member
2027 pid - the "si_pid" member
2028 uid - the "si_uid" member
2029 value_int - the "si_value.sival_int" member
2030 value_ptr - the "si_value.sival_ptr" member, specified as an integer
2031
2032 Example: send a SIGKILL to the specified process.
2033
2034 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
2035 and die "pidfd_send_signal: $!\n";
2036
2037 Example: send a SIGKILL to the specified process with extra data.
2038
2039 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
2040 and die "pidfd_send_signal: $!\n";
2041
2042 $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
2043 This is an interface to the Linux pidfd_getfd system call. The
2044 default for $flags is 0.
2045
2046 On success, returns a dup'ed copy of the target file descriptor
2047 (specified as an integer) returned (that is already set to
2048 close-on-exec), otherwise returns "undef". If the syscall is
2049 missing, fails with "ENOSYS".
2050
2051 Example: get a copy of standard error of another process and print
2052 soemthing to it.
2053
2054 my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
2055 or die "pidfd_getfd: $!\n";
2056 print $errfh "stderr\n";
2057
2058 $fh = IO::AIO::eventfd [$initval, [$flags]]
2059 This is a direct interface to the Linux eventfd(2) system call. The
2060 (unhelpful) defaults for $initval and $flags are 0 for both.
2061
2062 On success, the new eventfd filehandle is returned, otherwise
2063 returns "undef". If the eventfd syscall is missing, fails with
2064 "ENOSYS".
2065
2066 Please refer to eventfd(2) for more info on this call.
2067
2068 The following symbol flag values are available:
2069 "IO::AIO::EFD_CLOEXEC", "IO::AIO::EFD_NONBLOCK" and
2070 "IO::AIO::EFD_SEMAPHORE" (Linux 2.6.30).
2071
2072 Example: create a new eventfd filehandle:
2073
2074 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2075 or die "eventfd: $!\n";
2076
2077 $fh = IO::AIO::timerfd_create $clockid[, $flags]
2078 This is a direct interface to the Linux timerfd_create(2) system
2079 call. The (unhelpful) default for $flags is 0, but your default
2080 should be "IO::AIO::TFD_CLOEXEC".
2081
2082 On success, the new timerfd filehandle is returned, otherwise
2083 returns "undef". If the timerfd_create syscall is missing, fails
2084 with "ENOSYS".
2085
2086 Please refer to timerfd_create(2) for more info on this call.
2087
2088 The following $clockid values are available:
2089 "IO::AIO::CLOCK_REALTIME", "IO::AIO::CLOCK_MONOTONIC"
2090 "IO::AIO::CLOCK_CLOCK_BOOTTIME" (Linux 3.15)
2091 "IO::AIO::CLOCK_CLOCK_REALTIME_ALARM" (Linux 3.11) and
2092 "IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM" (Linux 3.11).
2093
2094 The following $flags values are available (Linux 2.6.27):
2095 "IO::AIO::TFD_NONBLOCK" and "IO::AIO::TFD_CLOEXEC".
2096
2097 Example: create a new timerfd and set it to one-second repeated
2098 alarms, then wait for two alarms:
2099
2100 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2101 or die "timerfd_create: $!\n";
2102
2103 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2104 or die "timerfd_settime: $!\n";
2105
2106 for (1..2) {
2107 8 == sysread $fh, my $buf, 8
2108 or die "timerfd read failure\n";
2109
2110 printf "number of expirations (likely 1): %d\n",
2111 unpack "Q", $buf;
2112 }
2113
2114 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags,
2115 $new_interval, $nbw_value
2116 This is a direct interface to the Linux timerfd_settime(2) system
2117 call. Please refer to its manpage for more info on this call.
2118
2119 The new itimerspec is specified using two (possibly fractional)
2120 second values, $new_interval and $new_value).
2121
2122 On success, the current interval and value are returned (as per
2123 "timerfd_gettime"). On failure, the empty list is returned.
2124
2125 The following $flags values are available:
2126 "IO::AIO::TFD_TIMER_ABSTIME" and "IO::AIO::TFD_TIMER_CANCEL_ON_SET".
2127
2128 See "IO::AIO::timerfd_create" for a full example.
2129
2130 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2131 This is a direct interface to the Linux timerfd_gettime(2) system
2132 call. Please refer to its manpage for more info on this call.
2133
2134 On success, returns the current values of interval and value for the
2135 given timerfd (as potentially fractional second values). On failure,
2136 the empty list is returned.
1743 2137
1744EVENT LOOP INTEGRATION 2138EVENT LOOP INTEGRATION
1745 It is recommended to use AnyEvent::AIO to integrate IO::AIO 2139 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1746 automatically into many event loops: 2140 automatically into many event loops:
1747 2141
… …
1797 forking, if "IO::AIO" was used in the parent. Calling it while 2191 forking, if "IO::AIO" was used in the parent. Calling it while
1798 IO::AIO is active in the process will result in undefined behaviour. 2192 IO::AIO is active in the process will result in undefined behaviour.
1799 Calling it at any time will also result in any undefined (by POSIX) 2193 Calling it at any time will also result in any undefined (by POSIX)
1800 behaviour. 2194 behaviour.
1801 2195
2196 LINUX-SPECIFIC CALLS
2197 When a call is documented as "linux-specific" then this means it
2198 originated on GNU/Linux. "IO::AIO" will usually try to autodetect the
2199 availability and compatibility of such calls regardless of the platform
2200 it is compiled on, so platforms such as FreeBSD which often implement
2201 these calls will work. When in doubt, call them and see if they fail wth
2202 "ENOSYS".
2203
1802 MEMORY USAGE 2204 MEMORY USAGE
1803 Per-request usage: 2205 Per-request usage:
1804 2206
1805 Each aio request uses - depending on your architecture - around 100-200 2207 Each aio request uses - depending on your architecture - around 100-200
1806 bytes of memory. In addition, stat requests need a stat buffer (possibly 2208 bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
1816 In the execution phase, some aio requests require more memory for 2218 In the execution phase, some aio requests require more memory for
1817 temporary buffers, and each thread requires a stack and other data 2219 temporary buffers, and each thread requires a stack and other data
1818 structures (usually around 16k-128k, depending on the OS). 2220 structures (usually around 16k-128k, depending on the OS).
1819 2221
1820KNOWN BUGS 2222KNOWN BUGS
1821 Known bugs will be fixed in the next release. 2223 Known bugs will be fixed in the next release :)
2224
2225KNOWN ISSUES
2226 Calls that try to "import" foreign memory areas (such as "IO::AIO::mmap"
2227 or "IO::AIO::aio_slurp") do not work with generic lvalues, such as
2228 non-created hash slots or other scalars I didn't think of. It's best to
2229 avoid such and either use scalar variables or making sure that the
2230 scalar exists (e.g. by storing "undef") and isn't "funny" (e.g. tied).
2231
2232 I am not sure anything can be done about this, so this is considered a
2233 known issue, rather than a bug.
1822 2234
1823SEE ALSO 2235SEE ALSO
1824 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a 2236 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
1825 more natural syntax. 2237 more natural syntax and IO::FDPass for file descriptor passing.
1826 2238
1827AUTHOR 2239AUTHOR
1828 Marc Lehmann <schmorp@schmorp.de> 2240 Marc Lehmann <schmorp@schmorp.de>
1829 http://home.schmorp.de/ 2241 http://home.schmorp.de/
1830 2242

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